Download Radiologic Technology, March/April 2016, Volume 87, Number 4

RADIOLOGIC
Journal of the American Society of Radiologic Technologists
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Volume 87, Number 4  March/April 2016
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DIRECTED READING ARTICLES
Medical Imaging of Neglected
Tropical Diseases of the Americas
PAGE 393
The Pediatric Urinary Tract and
Medical Imaging
PAGE 425
PEER-REVIEWED ARTICLES
Radiography Students' Learning:
A Literature Review
PAGE 371
Optimizing the Exposure Indicator
as a Dose Management Strategy
in Computed Radiography
PAGE 380
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Errata
In quiz question number 9 of the “Adverse Effects of Iodine-derived
Intravenous Radiopaque Contrast Media” Directed Reading, which
appeared in the July/August 2015 issue, the question stem used
the term degeneration. The correct term is degranulation. This
question will not be used for grading. Our thanks to the attentive
reader who alerted us to the error.
In the January/February 2016 issue, the link to the Eat Smart
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and Imaging Implications” Directed Reading should be
www.asrt.org/as.rt?wCu9zh.
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
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Radiologic Technology Editorial Review Board
Chairman
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Members
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Christina A Truluck, PhD, R.T.(N), CNMT
Daniel DeMaio, MEd, R.T.(R)(CT)
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Kelli Haynes, MSRS, R.T.(R)
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Contents
Volume 87, Number 4  March/April 2016
PEER-REVIEWED ARTICLES
Radiography Students’ Learning: A Literature Review
Anneli Holmström, Sanna-Mari Ahonen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 371
Optimizing the Exposure Indicator as a Dose Management Strategy in Computed Radiography
Euclid Seeram, Robert Davidson, Stewart Bushong, Hans Swan. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .380
DIRECTED READING ARTICLES
Medical Imaging of Neglected Tropical Diseases of the Americas
Patrick Jones, Jonathan Mazal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 393
The Pediatric Urinary Tract and Medical Imaging
Steven M Penny. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 425
COLUMNS
Editor’s Note
Registry Changes Make Life Easier. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 370
JRCERT Update
My Journey: Serving on the JRCERT Board of Directors . . . . . . . . . . . . . . . . . . . . . . . 447
In the Clinic
Radiographic Techniques in the 45° Posteroanterior
Oblique Projection of the Hand. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 449
Professional Review
Advantages and Disadvantages of Screening Breast Ultrasonography. . . . . . . . 455
Focus on Safety
Occupational Exposure and Adverse Effects in the
Radiologic Interventional Setting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 460
Teaching Techniques
Just-in-Time Teaching. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 465
Writing & Research
Writing With Style. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 468
My Perspective
Expect the Unexpected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 472
Technical Query
Increased Filtration and Image Receptor Exposure. . . . . . . . . . . . . . . . . . . . . . . . . . . . 474
Open Forum
In the Interest of Clarity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 477
Backscatter
Narrow-minded. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 480
ON THE COVER
This photograph of a paper quilling
piece created by Chad Schock, R.T.(R)
(MR)(CT), of Norfolk, Nebraska, was
inspired by a scan he saw during his CT
clinical rotation. The piece highlights
a lumbar vertebra, the kidneys, and
various muscles. Schock began working
on the project during his senior year of
radiography school and completed it 5
months later.
This symbol indicates expanded content.
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
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Editor’s Note
Registry Changes Make Life Easier
Lisa Kisner, BA, CQIA, ELS
T
he American Registry of Radiologic
Technologists (ARRT) recently announced
some changes, and astute readers will notice the
results of those changes on the Directed
Reading post-tests beginning with this issue. The first
change is an extension of the expiration date. Now,
Directed Readings are available for 3 years and will be
eligible for an additional 3-year renewal, making them
potentially available for 6 years. Previously, the posttests were available for 2 years, so members will have
more flexibility to take the quizzes when it is most convenient or beneficial to them.
The second change will surely brighten the day of
many journal readers. Under previous ARRT requirements, 20 post-test questions were needed for 1
Category A or A credit, 25 were needed for 1.5 credits, 30 for 3 credits, and so on. The latest ruling simplifies the post-tests for continuing education providers
and readers: 8 questions per credit. This change virtually cuts the number of questions you have to answer by
half, without reducing the credit amount.
The third change is another fairly significant one:
The ARRT now allows registered technologists to
repeat educational activities for credit, as long as they
are not repeated in the same biennium. That means you
may access your favorite Directed Reading articles—or
perhaps ones you struggled with—and earn credits
again. To do so, simply choose an article from your
list at www.asrt.org/drquiz, and purchase a new quiz
370
at 15% off the original cost of the course, or $8.50 per
credit. Of course, all Directed Reading quizzes published during your current membership period are still
free the first time you take them.
These 3 changes should help you get more from your
membership and make meeting ARRT requirements
easier than ever. Happy reading and credit earning!
For additional information, check out the ASRT
Scanner story at asrt.org/as.rt?BvrzKx or contact
[email protected].
Lisa Kisner, BA, CQIA, ELS, is the scientific publications
manager for the American Society of Radiologic
Technologists. She also serves as the staff liaison for the
Radiologic Technology and Radiation Therapist Editorial
Review Boards.
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
Peer Review
Radiography Students’ Learning:
A Literature Review
Anneli Holmström, PhD
Sanna-Mari Ahonen, PhD
Purpose To describe research methodology and findings concerning radiography students’ learning.
Methods Health sciences databases were searched to perform a traditional narrative literature review. Thirty-five peerreviewed articles published between 2000 and 2014 were analyzed using thematic analysis.
Results Specific methods of learning were found to be of the most interest. The studies focused primarily on the use and
usability of a method or the students’ general experiences of it. The most commonly studied methods were e-learning
and interprofessional learning, which students perceived as positive methods for theoretical studies and clinical training. Students’ learning regarding research was the focus of only one article reporting a wide variety of students’ research
interests. Most studies reported quantitative research gathered from questionnaires and surveys.
Conclusions Additional research, especially from a qualitative point of view, is needed to deepen the evidence-based
knowledge of radiography student learning.
Keywords learning, education, radiography, student, radiologic technologist, radiography education
T
he education of radiography students has become
more student-centered, with the focus of instruction moving from the teacher to the student.1-4
Educational goals are expressed as students’ learning outcomes and competencies, both in European and in
North American institutions.2-4 The students’ responsibility for their own learning has increased. Students are obligated to show progression in their studies and are expected to study more independently than previously.1,4
In the European Qualifications Framework (EQF),
learning outcomes are defined as knowledge, skills, and
competence. Knowledge refers to a radiography graduate’s
ability to demonstrate a critical understanding of the theory and principles of the profession (eg, radiation physics,
radiation protection regulations, positioning, immobilization, and beam-shielding devices). Skills include the ability to demonstrate mastery of equipment and technique
and innovation by solving complex and unpredictable
problems presented in a clinical setting (eg, the ability
to use appropriate imaging, medical, and nonmedical
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
devices in an effective, safe, and efficient manner, and to
assess patients and their conditions to justify and optimize
examinations or treatment procedures). Competence
means making responsible decisions in unpredictable
work contexts and managing the professional development of individuals and groups.2,3
Along with the movement toward using learning outcomes, the level of radiography instruction has changed
from vocational education to university-based education.1,2 In Europe, the Bologna process, a reform process
aimed at creating the European Higher Education Area,
has guided radiography education on a general level
toward harmonized qualification at a higher level.5
Along with the change to higher education, the connection between theory and practice is emphasized
more than before.1,4,5 In addition to memorizing facts,
students also must build upon that knowledge and
apply it in the laboratory setting and the clinical environment. 4 The theory-practice connection is evidenced
in EQF learning outcomes as each radiography graduate
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Radiography Students’ Learning: A Literature Review
demonstrates an ability to responsibly carry out work in
a safe manner when ionizing radiation is in use and take
into account current safety standards, guidelines, and
regulations so that she or he can act as an autonomous
professional.2,3
This literature review describes research methods
and findings releated to radiography student learning.
These findings can be used in planning curriculum,
evaluating learning, developing teaching methods, and
conducting further research. The research questions
were:
1. What is known about the radiography students’
learning in light of the research?
2. What kind of research methods have been used in
studies concerning radiography students’ learning?
In this article, the term radiography student refers to
a radiologic technologist student whose studies prepare
her or him to work in the medical imaging profession
including radiography, magnetic resonance imaging,
computed tomography, sonography, and nuclear medicine. The term radiography graduate refers to a radiologic technologist program graduate who is educationally
prepared to work in diagnostic radiography. The term
radiographer refers to a radiologic technologist whose
primary practice area is diagnostic radiography.
Methods
A literature review was conducted to gain an overview
of the existing research about radiography students’
learning in radiography education because it is a suitable
method for outlining what is known about a phenomenon under study.6,7 Peer-reviewed research articles that
met a specific selection criteria were collected from the
CINAHL, Medline, and PubMed databases (see Box
1). In addition, the Radiography journal archives were
searched manually to complete the data collection. The
search terms used were radiography, student, and learning. Both researchers collected data individually, but
neither had access to full text for all the articles. Both
authors read the abstracts to assess the articles’ relevance.
Abstracts that lacked the student point of view, were not
original research, were not written in English, or that
concerned graduate or radiation therapy students were
rejected. Thirty-five articles met the selection criteria.
Most (n  22) were from the United Kingdom and
372
focused on diagnostic radiography students’ learning and
on students’ theoretical studies. The data were organized
using literature review matrices including the phenomena and purpose of the study, methods, and central findings.7 The data were analyzed with thematic analysis
according to the themes chosen in the matrices.
Results
The most common phenomenon under study concerns a learning method in theoretical or clinical studies as experienced by the students. Learning methods,
such as the use of learning technologies, online studies
and e-learning, multiprofessional or interprofessional
learning, inquiry-based or research-based learning, peer
assessment, and clinical evaluation, were studied, with
a focus on student-orientation and student attitudes
toward the method used.
Studies also focused on assessing students’ learning
of skills and competencies (eg, communication skills,
critical thinking skills, radiographic interpretation skills,
and knowledge of anatomy). Students’ research interest
regarding their own thesis also was studied (see Figure 1).
Primary findings about radiography students’ learning in theoretical studies provided evidence on students’ positive or negative experiences of or attitudes
toward a particular learning method. Methods students
considered as positive and beneficial included:
¡ Peer assessment.8
¡ Group work and teamwork.8-11
¡ Research-based or inquiry-based learning.9-11
¡ Multiprofessional or interprofessional learning.12-15
¡Workshops.16
¡ Blended learning.16-19
¡ e-learning (online studies or technology
enhanced learning).18-24
Box 1
Literature Review Selection Criteria
Articles must be:
■ Published between January 2000 and April 2014.
■ Available in full text.
■ Focused on radiography students’ learning in diagnostic
radiography in a bachelor’s degree program.
■ Inclusive of the student perspective in the research question
and results.
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Holmström, Ahonen
Students reported that peer
Learning Methods
assessment enhanced their abilPeer-assessment
e-learning
ity to contribute during a group
Group work/teamwork
Short message texting
8
project, and that working in
Research-based learning
OSCE
Interprofessional learning
SOLAR
groups toward a common goal
Workshop
Site of clinical training
had a beneficial and supportive
Blended learning
Role models
e-learning
Community training & PBL
effect on learning,11,22 increasing
Audit of clinics
their knowledge and understanding.10 Workshops were considered
beneficial for developing commuResearch,
nication skills.16 Teamwork was
Research
Theoretical
Clinical
academic
identified as a key responsibility
studies
studies
interest
interests
of a radiographer.9
Some negative experiences and
barriers to learning in theoretical
Anatomy knowlege
Radiographic interpretation
studies were reported in blended
Group work
Figure 1. The phenomena in
18
learning and interprofessional
Communication skills
research concerning the learnIntegration of professional
learning.12,13,15 Despite the flexibiling of radiography students.
and academic skills
ity of online or other technologyAbbreviations: OSCE, objective
Academic performance
Critical thinking skills
structured clinical examination;
assisted methods, some students
Information literacy skills
PBL, problem-based learning;
in a blended learning setting pre18,22
SOLAR, student oriented learning
ferred lectures. In interprofesSkills and Competencies
about radiography.
sional settings, student learning
was found to be hindered by the
size15 and diversity12 of the groups and by the students’
skills were reported as challenges to student learning
Learning Methods
preconceived ideas of other professions.13
in clinical studies.25
In clinical training, students reported positive
The factors that students said helped them avoid
experiences with e-learning methods such as online
unsafe practices included the clinical training site itself
case discussion19 and online supported clinical studand having clinical radiographers as role models.29,30,31
20,25
ies. In addition, students considered technology,
Students in clinical training also reported that comsuch as short message texting, 26 objective structured
munity training32 combined with problem-based learn27
clinical examination (OSCE), and student oriented
ing33 was beneficial and positive. Price et al measured
28
learning about radiography (SOLAR), to be benefistudents’ satisfaction in clinical placements with a tool
cial. In the OSCE study, the students’ clinical skills
developed from the audit of clinical placements, which
were examined according to checklists and grades in
was found to promote the evaluation of radiography stu2 OSCE sessions with simulated patients and several
dents’ learning.34 However, clinical placement providers
stations. Each student’s scores were then collated
should address the lack of using radiographic research
station by station and compared with other marks
findings because, according to students, research findachieved by the same student in other aspects of his or
ings usually were not used in clinical practice.30
27
her degree profile. SOLAR is a computer-based, caseLearning skills and competencies were studied by
oriented program in which the student constructs a
assessing students’ theoretical and cognitive perforclinical action plan in response to a scenario and then
mance. Students’ retention of anatomy knowledge
compares that plan with one prepared by an expert.28
depended on the assessment methods employed and
However, problems with online access and students’
time elapsed, thus supporting the use of a variety of
lack of information and communications technology
assessment methods. 35 The portfolio was identified as
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
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Radiography Students’ Learning: A Literature Review
a capable assessment tool integrating academic and
professional skills throughout a radiography program.
However, a multidimensional assessment approach
would help to gauge students’ individual progress and
ability to meet expectations.36
Studies evaluating students’ critical thinking skills
indicated a need for reassessment of teaching methods,
student support, and a difference between the students’
self-assessment regarding development of these skills
and actual written assessment. 37,38 Substantial development in accessing scholarly information was demonstrated after an online electronic information skills
(OEIS) intervention, demonstrating its success in information literacy development and in preparing students
to be independent learners.39
According to final year students’ opinions, poor academic performance is connected to poor preparation,
lack of independent study, difficulty in understanding
learning content, misinterpretation of assessment questions, and inefficient studying techniques. Students
reported a preference for assessment-oriented teaching
as an improvement strategy, yet the strategies they identified were learner centered—studying in advance of an
assessment, triangulating information, and increasing
the frequency of independent study.40
Accuracy of students’ skills in radiographic interpretation also was studied. A comparison of radiography
students’ and radiologists’ performance in analyzing
thorax radiographs found no correlation between diagnostic performance and either field-dependency or
visual search.41
Only one article discussed radiography students’
learning and their research or academic interests.
Dempsey et al gave students a free hand in choosing the research topic for a group work project.
Statistically significant differences between students’
interests were found among students of diagnostic
radiography, nuclear medicine, and radiation therapy,
whereas students in a degree program shared a strong
unifying common interest. It is suggested that the
domains of interest are highly descriptive of the given
clinical worlds. 42
Research Methods Used
Most studies (n  20) concerning radiography
students’ learning applied quantitative data collection methods such as surveys, questionnaires, student
grades, or test score recordings.* Methodological triangulation (n  10) was used including open-ended questions in a questionnaire or combining a survey with a
focus group interview.† Out of 28 questionnaire studies,
6 used an online questionnaire.10,21-23,26,31 A qualitative
approach (n  5) was applied by using interviews, focus
groups, open-ended questions, or grounded theory
method.9,12,25,40,42 Most of the studies were cross-sectional
studies, but some longitudinal studies also were used
that included collecting students’ experiences at the
beginning and at the end of the module or academic
year.13,17,18,39 The data were collected from radiography
students alone‡ (n  19) or together with other students
or professionals such as radiographers, instructors, and
medical and nursing students (n  16).§
The studies had descriptive, evaluative, and reporting purposes aiming to survey,13,28 determine,12 identify, 31 assess,15,17,30,32 evaluate,24 analyze, 42 investigate,18,26,29,40
test,16 evidence, 35 compare, 37 provide evidence, 39 or
explore14,41 radiography students’ learning. The goals
also were to discuss,9,10 describe, 8,11,23 demonstrate,22 consider,27 ascertain,25 report, 34 reflect,21 produce,20 incorporate,19 devise, 38 establish, 36 and implement33 radiography
students’ learning. Studies aimed to describe students’
experiences and the implementation of a particular
method, to provide guidelines for the use of a particular
method, or to provide evidence on the method’s usefulness and influences on students’ learning experiences
and learning outcomes.
*References 8, 10, 13, 15-18, 22-24, 27-31, 34, 35 ,37, 38, 40
†References 11, 14, 19-21, 26, 32, 33, 36, 39
‡References 9-11, 16, 19-22, 24, 27, 28, 30, 31, 34, 35, 37-40
§References 8, 12-15, 17, 18, 23, 25, 26, 29, 32, 33, 36, 41, 42
374
Discussion
Some articles concerned radiography students’
knowledge,15,35 skills,16,36-39,41 and competence27 during
their education—the very elements of learning outcomes defined by the EQF. 3 The research topics usually originated from the curriculum and the practices
used in radiography education. Analyzing First Cycle
radiography programs in Europe and Japan, Akimoto
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
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Holmström, Ahonen
et al found wide variability in the curricula and learning outcomes between and within states despite efforts
to unify radiography education.1 Differences in curricula and in the emphasis on learning outcomes might
be a reason for the research topics to have a different
focus, and radiography students’ learning in accordance with outcomes has not been at the center of the
research. Some authors point out that radiographers’
professional expertise is in the technological aspects of
radiography, which radiography students learn under
the supervision of academic educators and clinical
supervisors.1,43,44 Conducting research in accordance
with radiography students’ learning outcomes on
knowledge, skills, and competency in imaging and
technology will ensure that standards of expertise are
maintained in the profession.
Most of the articles in this review focused on learning
methods in radiography education in theoretical studies or in clinical training.8-28 These articles focused on
radiography students’ orientation and attitudes toward
the learning methods. Many of the learning methods
studied were new, and radiography students were experimenting with them for the first time. Understandably,
the researchers wanted to gather information about
the students’ opinions and experiences on the methods
applied. However, the findings did not show how the
learning methods promoted learning in accordance
with learning outcomes. In the future, research should
be focused more on the adequacy of different learning
methods in accordance with learning outcomes.
Many of the articles on learning methods focused
on radiography students’ learning by using e-learning
methods,19-28 which might reflect the fast development
of information and communications technology in
education. According to the results, e-learning methods
such as podcasts, Flash presentations, wikis, SOLAR,
OEIS, or short text messages were reported to improve
students’ learning in theoretical studies and in clinical
training.18,20,21,26-28 These positive findings might reflect
the improvement of students’ information and communication technology skills in everyday life. Texting facilities and networks also were found to support communication between the clinical placement facility and the
university.25 However, there were research findings contradictory to those.18,22,25 There is a strong tendency to
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
develop e-learning methods instead of on-site instruction in classrooms. This tendency shifts the responsibility of learning onto the student and requires more
self-direction and independence than the traditional
method. Therefore, a need exists to identify the content and topics that can best be learned via e-learning
and to determine whether e-learning slows learning.
Learning in a multidisciplinary group,15 interprofessional education,12 interprofessional working,13 and
multiprofessional learning14 also were studied. An interprofessional course is in accordance with multiprofessional collaboration and teamwork in real-life health
care, and researchers report that this is a successful,
albeit challenging, method. Thus, learning that happens
in interprofessional courses must be planned carefully
so that the students understand the connection between
the radiography content and the critical points of cooperation while studying with other health education students. Group work typically was an effective and wellliked method of learning among radiography students.
Learning in clinical training regarding the importance of the learning context as a promoting factor
of learning was demonstrated in some articles.29,32-33,41
Health care learning contexts, such as community
training32 or a specific diagnostic radiography context, 33,41 give students the possibility to experience real
patient situations in which they learn problem solving
and link theoretical knowledge with practice.32,33 In
ultrasonography, for example, students learned to apply
their skills in real-life scenarios while offering a service
to patients.33 Radiography students also considered staff
radiographers as role models when working with actual
patients. 30 Mifsud et al highlighted the importance
of the learning context, presenting research findings
about learning to work with claustrophobic and anxious
patients in clinical training for magnetic resonance
imaging. 45 Learning in a variety of diagnostic radiography contexts or modalities offers students experiences
they will not get anywhere else.
In the radiography profession, learning occurs in
practice with others and in real-life situations. By participating in clinical practice, the student gradually changes
his or her role from newcomer to full member of a profession.46 Learning in genuine situations allows the student
to understand and use radiography knowledge.47-49
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Radiography Students’ Learning: A Literature Review
However, learning in the clinical context does not
automatically promote radiography students’ learning.
The studies in this literature review showed that learning during clinical training is dependent on many factors, including the students, curriculum, supervision,
and clinical practice, and that mere clinical placement
does not always promote learning. According to students, one factor preventing learning in the clinical setting is a lack of using research findings because radiography students’ clinical instruction should be based on
research-based practice. 30 Brown et al found significant
differences between the students’ perception of their
actual and their ideal clinical learning environments.
The study emphasized the importance of a supportive
clinical learning environment, in which effective 2-way
communication is practiced among students, teachers, and others responsible for supervising students.29
In a study by Mifsud et al, students described their
experiences as lacking hands-on practice and reported
feeling uncomfortable, unsupervised, and unwelcome.
Interestingly, students’ learning was found to be based
primarily on competencies and tasks described by and
expected from the university, and students had no motivation to learn more than was required. However, the
students observed that radiographers’ work in magnetic
resonance imaging was versatile and facilitative for their
learning more than the university assumed. 45
Students’ skills and competencies were considered
in articles regarding students’ theoretical and cognitive
performance. According to Ng et al, students’ progress
should be based on a multidimensional assessment.36
This finding was confirmed by Castle, who found a
difference between the students’ own report on their
development of critical-thinking skills and actual written assessment that required demonstration of these
skills. 37 These findings highlight an important question
of how radiography students are empowered to become
reflective and critical practitioners. 50
To complete their radiography studies successfully,
students must possess sufficient learning abilities. Finalyear students’ report that poor academic performance is
connected to individual performance, learning content,
and study techniques. In clinical and theoretical studies, special attention should be paid to students’ study
techniques. 40 This also was evident in an assessment of
376
students’ retention of anatomy knowledge.35 Students
with inefficient studying habits and skills need more
supervision, and they should be given more attention at
the beginning of the program to ensure they have the
skills required for successful learning.
Students’ opinions of learning are invaluable for
gaining a student-centered approach, and decisions
on improvement should be made with all stakeholders
including students. Good examples of improvement
methods are cooperative learning methods such as
workshops8,16,39 and group work.8 Studies reported that
students’ communication skills progressed16 and peer
assessment encouraged them to participate in group
work.8 The students’ information literacy skills also
developed, and those skills prepared them to be independent learners. 39
Manning and Leach studied students’ clinical skills
in accurate radiographic interpretation of thorax radiographs.41 In Europe, there has been debate over extending the role of radiographers to interpret radiographs.51,52
For example, in the United Kingdom there are examples
of image interpretation studies within both preregistration and postregistration radiography programs. 53
Akimoto et al questioned whether expanding the technologist’s role to diagnostic reporting in Europe would
be at the expense of the more technological aspects
of radiography and whether this kind of progress is a
threat to the profession. Radiography education should
be carried out in ways that enable radiographers to
enhance their role without sacrificing their technological competencies.1
In this literature review, only one article was found
to discuss learning pertaining to research or academic
interests. 42 According to the EQF, a bachelor’s degree
program in radiography includes carrying out shortterm and practice-oriented research while presenting
and publishing results and applying national and international findings in professional practice. 3 This goal
has become more important with the change in radiography education from vocational to higher education.
The goal might be new to some fields of education and
might require that curricula be modified. In addition,
instructors should be able to justify conducting research
to radiography students in relation to their professional
practice and personal development.
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Holmström, Ahonen
In terms of the research methods used in studies
concerning the learning of radiography students, nearly
2 out of 3 articles were quantitative in nature, and in
28 studies the information was gathered through the
use of a questionnaire. The knowledge base of quantitative studies about radiography students’ learning is
important because quantitative instruments are based
on previous research findings. However, the qualitative approach is the starting point of studying poorly
known phenomena. 6,7 Because few qualitative studies
about radiography education exist, quantitative studies often apply the results from other fields of research,
mainly education and nursing sciences. However, the
significance of qualitative, theory-developing research
conducted by radiography scholars and researchers
ought to be emphasized because it provides radiography educators with deep, individual-based, qualitative
knowledge and completes the evidence base along with
the quantitative findings.
In this literature review, subjectivity was minimized
by selecting the data according to the criteria agreed
upon beforehand with both researchers’ consent. The
authors’ own opinions did not revise the data selection. Subjectivity also was avoided when analyzing the
articles’ content in relation to the research questions
proposed by both authors of this review. The authors
formulated the research questions and performed the
literature review according to research ethics proper
for a literature review.54 Leaving the research questions
open-ended made it possible to describe radiography students’ learning broadly as in the articles.
One shortcoming of this literature review was the
possibility of biased results because relevant articles
were not considered as a result of the researchers’ limited access to full texts. In addition, it is possible that
the search strategies and data selection criteria biased
the data and findings. Although the included articles
were peer reviewed, their quality varied in relation to
how the study was conducted and reported. The findings of this literature review might not be generalized,
especially because of the cultural variety of educational systems and differences in curricula, radiography
practices, and health care systems. The geographical
and global diversity of the study authors and study
subjects might be a challenge when comparing results
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
conducted in different circumstances. However,
these findings might be considered a brief qualitative
description on the current knowledge and research
conducted on radiography students’ learning, based
mainly on European research reports.
Conclusion
Research concerning radiography students’ learning focus on learning methods such as e-learning and
interprofessional learning in theoretical studies and
in clinical training. Learning also is studied from the
viewpoint of student skills, yet research on learning outcomes from the student point of view has been of lesser
interest. Research on learning in relation to research or
academic interests also is rare.
Most research methods used in studies concerning
radiography student learning are quantitative. More
qualitative research is needed to deepen the evidencebased knowledge of radiography students’ learning.
Additional research, with a focus on learning in a variety of contexts and modalities, would help instructors
understand and develop curricula in different imaging contexts. Future research on learning practices as
related to outcomes in radiography education also could
benefit instructors and students.
Anneli Holmström, PhD, is head of the radiography
and radiation therapy degree program for Oulu University
of Applied Sciences School of Health and Social Care in
Finland. She can be reached at [email protected].
Sanna-Mari Ahonen, PhD, is a postdoctoral researcher
for University of Oulu Institute of Health Sciences in Finland.
Received June 22, 2015; accepted after revision
September 10, 2015.
Reprint requests may be mailed to the American Society
of Radiologic Technologists, Communications Department,
at 15000 Central Ave SE, Albuquerque, NM 87123-3909,
or emailed to [email protected].
© 2016 American Society of Radiologic Technologists
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33. Kiguli-Malwadde E, Mubuuke AG, Businge F, Nakatudde
R, Bule S. Evaluation of ultrasound training in the problem based learning radiography curriculum at Makerere
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34. Price R, Hopwood N, Pearce V. Auditing the clinical
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35. Hall AS, Durward BR. Retention of anatomy knowledge by
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Peer Review
Optimizing the Exposure Indicator
as a Dose Management Strategy
in Computed Radiography
Euclid Seeram, PhD, FCAMRT
Robert Davidson, PhD, FIR
Stewart Bushong, ScD, FAAPM, FACR
Hans Swan, PhD
Purpose To investigate a technique for optimizing radiation dose and image quality for a computed radiography system.
Methods Entrance skin doses were measured for phantom models of the pelvis and lumbar spine imaged using the
vendor’s recommended exposure settings (ie, the reference doses) as well as doses above and below the vendor’s
recommended settings for both body parts. Images were assessed using visual grading analysis (VGA).
Results The phantom dosimetry results revealed strong positive linear relationships between dose and milliampere
seconds (mAs), mAs and inverse exposure indicator (EI), and dose and inverse EI for both body parts. The VGA showed
that optimized values of 16 mAs/EI  136 for the anteroposterior (AP) pelvis and 32 mAs/EI  139 for the AP lumbar
spine did not compromise image quality.
Discussion Selecting optimized mAs reduced dose by 36% compared with the vendor’s recommended mAs (dose)
values.
Conclusion Optimizing the mAs and associated EIs can be an effective dose management strategy.
Keywords dose optimization, exposure indicator, visual grading analysis, entrance skin dose
T
he exposure indicator (EI) is a numerical
parameter used in computed radiography (CR)
to inform operators about the amount of exposure to the imaging plate. The EI indicates
whether appropriate radiographic techniques were used
for an examination,1 and can help radiologic technologists control and manage radiation dose. In fact, EI can
be “used as a surrogate for dose management.”2 Furthermore, EI is “the key to controlling exposure levels” in
CR, 3 and optimizing the EI is closely linked with optimizing kilovoltage (kV) and milliampere seconds
(mAs).4 A few years ago, a standardized EI was proposed5; however, many existing digital radiography systems still use different EI systems. In this study, EI is
used as a general exposure term, as opposed to the S
(sensitivity) number used by Fuji CR systems.
Two significant and fundamental problems in CR
imaging are exposure creep (ie, using exposures greater
than required to produce diagnostic-quality images)
380
and the wide exposure latitude, or dynamic range, of
the digital detector. The potential harm associated with
exposure creep is unnecessarily high radiation doses to
patients, 6 whereas wide exposure latitude can result in
images with high noise levels caused by low exposure
or increased radiation doses to patients caused by high
exposure. 4,7
Literature Review
The literature is sparse regarding the use of EI as part
of an optimization strategy in digital radiography, and further research is needed to understand its relationship to
exposure techniques and patient exposure.1,6,7
With respect to exposure techniques, “manipulation of the operating kVp cannot stand alone even with
digital systems, and concomitant compensation of the
applied mAs, together with adequate scatter control
are necessary.”7 One concern in digital imaging is the
inverse relationship between mAs and image noise. As a
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
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Seeram, Davidson, Bushong, Swan
result, optimization must consider image quality along
with the dose per image. Increasing the dose per image
decreases noise, thus improving image quality.8
The purpose of this study was to investigate optimization of the EI of a CR imaging system as a radiation
dose management strategy, in keeping with the ALARA
(as low as reasonably achievable) principle and to compare the optimized EI with the manufacturer’s recommended values for the anteroposterior (AP) pelvis and
AP lumbar spine projections.
Methods
The imaging equipment used in this study was a
BuckyDiagnost Optimus 50 (Philips Healthcare). To
ensure that the x-ray generator performance was within
acceptable limits, 3 quality control tests were performed, as outlined by Papp: radiation output, exposure
linearity, and exposure reproducibility.9
The anthropomorphic phantom used in this study
was a transparent pelvis and lumbar spine (L1 to L5)
phantom designed to represent an average-sized man
approximately 5 ft 9 in (175 cm) tall and weighing
162 lb (73.6 kg) (Radiology Support Devices). The
phantom contained human skeletal pelvis and lumbar
spine parts embedded in anatomically accurate, tissueequivalent materials with the same radiation absorption
characteristics as living tissue.
Exposure Technique Selection
The pelvis phantom was 20 cm thick, and the lumbar
spine was 25 cm thick. For a 20-cm thickness, the manufacturer suggests using exposure factors of 25 mAs and
80 kVp to produce an acceptable AP image of the pelvis.
However, the control panel did not allow an operator to
select 80 kVp; it defaulted to a setting of 81 kVp when pelvis and lumbar spine were selected on the control panel.
Therefore, all entrance surface dose (ESD) measurements
for the AP pelvis reflect imaging with 25 mAs and 81
kVp. This is referred to as the reference exposure technique.
For the AP lumbar spine exposure, technique factors
were selected from the manufacturer’s technique chart.
These factors were listed as 50 mAs and 80 kVp. Again,
the kVp setting on the control panel defaulted to 81 kVp.
Therefore, 50 mAs and 81 kVp was used as the reference
exposure technique for the AP lumbar spine.
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
Dose Measurement
The ESD measurements were obtained using
a ThinX RAD calibrated dosimeter (Unfors
Instruments) free-in-air for both the AP pelvis and the
AP lumbar spine. These measurements were recorded
based on the protocol established by the American
Association of Physicists in Medicine and described in
its Report No. 31.10 For the AP pelvis, 4 ESD measurements were recorded for each of the following mAs
values: 6.3, 8, 12.5, 16, 20, 25 (the reference mAs), 32,
40, and 50, all with a fixed kVp of 81. For the AP lumbar
spine, 4 measurements were recorded for each of the following mAs values: 16, 20, 25, 32, 40, 50 (the reference
mAs), 63, 80, and 100. Thirty-six dose measurements
were recorded for the AP pelvis (4 measurements for
each of the 9 mAs settings) and 36 for the AP lumbar
spine (4 measurements for each of the 9 mAs settings
for the lumbar spine). The mean milligray per mAs setting was calculated for each of the 9 settings for both
the AP pelvis and AP lumbar spine.
Image Acquisition
The images were acquired using a Fuji CR system
(FCR XG5000) including a review workstation. The
imaging plate used for image acquisition was the Fuji
standard 35-cm  43-cm ST-VI imaging plate for general-purpose radiography. Before acquiring the images
used in this study, the EI (ie, the S number) was first
calibrated using the calibration procedures outlined
by Fuji.11 For the AP pelvis, 3 images were acquired
for each of the following mAs technique settings at
81 kVp: 6.3, 8, 12.5, 16, 20, and 25 mAs (reference
mAs) Three images also were acquired using each
setting of 81 kVp and mAs of 32, 40, and 50. A total
of 27 images were acquired. For the AP lumbar spine,
3 images were then acquired for each of the following mAs technique settings at 81 kVp: 16, 20, 25, 32,
40, and 50 (reference mAs). Three images also were
acquired using each setting of 81 kVp and mAs of 63,
80, and 100. A total of 27 images were acquired and
processed by the CR reader.
Image Quality Evaluation
Seven volunteer observers independently evaluated
54 images of the AP pelvis and AP lumbar spine. All
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Optimizing the Exposure Indicator as a Dose Management Strategy in Computed Radiography
of the observers were radiologic technologists with
at least 10 years of experience teaching radiographic
technique and positioning in classrooms, laboratories,
and hospitals. No time limit was imposed for assessment, and observers could pause during the assessments as needed to reduce the potential effects of
fatigue on their ability to evaluate the images.
Twenty-seven images of the AP pelvis and 27 images
of the AP lumbar spine were displayed for assessment.
Each image was obtained with a different ESD. To
establish the optimized mAs and EIs for the AP pelvis
and AP lumbar spine, observers were asked to indicate
whether the image displayed on a computer monitor
was acceptable or unacceptable in terms of image mottle (noise). This method of establishing an optimized
mAs/EI was described by Peters and Brennan.12
To determine the dose-image quality optimization,
all observers evaluated all images by comparing the test
images with the reference images. Observers used criteria that define the degree of visibility of certain anatomical structures and a visual grading analysis (VGA)
method to assess image quality.
Table 1 defines 4 key terms that describe the degree
of visibility as established by the Commission of
European Communities.13 The anatomical criteria for
evaluating image quality based on the reproduction and
visualization of defined structures on AP pelvis and
AP lumbar spine images are listed in Table 2. VGA is a
simple method of subjectively assessing image quality
based on the visibility and reproduction of anatomical
structures and characterized by “powerful discriminating properties” and applied in a “controlled scientific
manner.”14-18 Sund et al noted that an assumption of
visual grading is that “the visibility of normal anatomy
is strongly correlated to the detectability of pathological structures.”14 VGA is a well-established, valid, and
popular tool for image assessment.
Statistical Analysis
Descriptive statistics, such as sample size, mean,
standard deviation, and range, were computed for the
dosimetry data, the EI data, and the VGA image quality
scores. In addition, the Pearson correlation was applied
to examine the correlation between the ESD and the
EI and dose and mAs.15,16 The VGA study results for
382
Table 1
The Commission of European Communities
Definitions of the Degree of Visibility for
Anatomical Structures in an Image13
Term
Definition
Visualization
Characteristic features are detectable but
details are not fully reproduced; features are
just visible.
Reproduction
Details of anatomical structures are visible
but not necessarily clearly defined; detail is
emerging.
Visually sharp
reproduction
Anatomical details are clearly defined; details
are clear.
Important
image details
These define the minimum limiting dimensions
in the image at which specific or abnormal
anatomical details should be recognized.
Table 2
Commission of European Communities
Anatomical Criteria for Images13
Part and
Projection
Image Criteria
AP pelvis
Visually sharp reproduction of the:
 Sacrum and its intervertebral foramina.
 Pubic and ischial rami.
 Sacroiliac joints.
 Necks of the femora (no foreshortening or
rotation).
Greater trochanters.
 Cortex/trabecular patterns.
AP lumbar
spine
Visually sharp reproduction of the:
 Upper and lower end plate surfaces.
Pedicles.
 Intervertebral joints.
 Spinous and transverse processes.
 Cortex/trabecular patterns.
Abbreviation: AP, anteroposterior.
visualization of anatomical structures in the images,
specifically the mean criteria and the mean total image
scores, were examined with the hypothesis that images
produced with the different mAs values could not show
differences with respect to image quality. Statistical
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
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Seeram, Davidson, Bushong, Swan
significance was assessed using analysis of variance.17,18
Interobserver agreement in the VGA study was assessed
using Cohen kappa analysis.17,19 Furthermore, a P value
of less than 5% (P  .05) was used to determine statistical significance.20,21 All statistical analysis was performed using the Statistical Analysis Software (SAS)
system (SAS Institute).22
Table 3
Dose Measurement Resultsa
Pelvis
mAs
Lumbar Spine
Mean mGyb
mAs
Mean mGyb
50
6.45
100
13
40
5.17
80
10
32
4.14
63
7.98
25
3.24
50
6.36
20
2.60
40
5.09
16
2.09
32
4.07
12.5
1.63
25
3.19
8
1.06
20
2.56
6.3
0.83
16
2.05
c
c
Results
Dosimetry
The results of dosimetric measurements for the AP
pelvis and the AP lumbar spine are shown in Table 3.
Graphs of the mean dose in milligray for the AP pelvis
and the AP lumbar spine were plotted as a function of
mAs, the inverse EI and the mAs, and the dose and the
inverse EI (see Figure 1). This shows a strong positive
linear relationship (r  0.999) for both the AP pelvis
and the AP lumbar spine.
Image Acquisition
Images of both phantoms were acquired at the reference mAs settings as well as mAs settings above and
below the reference values, which are referred to as test
Abbreviations: mAs, milliampere seconds; mGy, milligray.
a
All images were obtained at 81 kVp.
b
Free-in-air measurements.
c
Reference exposure techniques.
Dose and mAs
Inverse EI and mAs
Dose and inverse EI
Mean dose (mGy)
0.02
5
1/mean EI
AP Pelvis
Mean dose (mGy)
6
4
3
0.01
6
5
4
3
2
2
1
1
20
10
30
mAs setting
40
20
10
50
30
mAs setting
40
0.01
50
1/mean EI
0.02
Mean dose (mGy)
0.02
12
1/mean EI
AP Lumbar Spine
Mean dose (mGy)
14
14
10
8
6
0.01
12
10
8
6
4
4
2
2
20
30
40
50
60
70
80
90
100
mAs setting
20
30
40
50
60
70
mAs setting
80
90
100
0.01
0.02
1/mean EI
Figure 1. Graphs of the mean dose in mGy plotted as a function of mAs, the inverse exposure index (EI) and the mAs, and the dose and the inverse
EI for the AP pelvis and the AP lumbar spine.
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
383
Peer Review
Optimizing the Exposure Indicator as a Dose Management Strategy in Computed Radiography
mAs values. The EIs associated with the mAs settings
the pelvis images are shown in Table 7, and a graph of
are reported as well. Image acquisition results for the
the VGA scores plotted as a function of mean dose is
shown in Figure 4, which demonstrates that the VGA
AP pelvis and AP lumbar spine are shown in Table 4.
scores increase (ie, image quality increases) as the dose
For each mAs setting, 3 images were obtained and the
increases. Furthermore, a positive linear relationship
associated EIs recorded. The images produced with the
appears as the dose increases from 1.63 mGy to 6.45
lowest mAs and selected as acceptable by all observers
mGy (12.5-50 mAs, respectively). There also is a sharp
were chosen as the optimum mAs (see Table 5). Image
decrease in the VGA scores as the dose decreases from
number 3 for the AP pelvis (obtained with 16 mAs)
and image number 23
Table 4
for the AP lumbar spine
(obtained with 20 mAs)
AP Pelvis and AP Lumbar Spine Image Acquisition Resultsa
were identified as the
AP Pelvis
AP Lumbar Spine
optimized mAs setting.
Mean EIs
Mean mGy Inverse
Mean EIs
Mean EI Inverse
The optimized mAs and
mAs mGy
(S No.) (S No.)
Mean EIb mAs mGy (S No.) (S No.)
Mean EIb
corresponding optimized
50
6.45
43
43
0.023
100
13
45
45
0.022
EI, together with refer44
45
ence mAs and the manu44
45
facturer’s recommended
40
5.17
54
54
0.018
80
10
57
55
0.018
EI range for the AP pelvis
55
55
and AP lumbar spine, are
54
55
shown in Table 6.
32
4.14
71
69
0.014
63
7.98
71
70
0.014
The manufacturer’s
68
71
recommended EI ranges
68
70
do not provide mAs setc
c
25
3.24
88
86
0.011
50
6.36
88
88
0.011
tings for the body parts
86
90
studied. The manufac84
88
turer’s mAs used in this
20
2.60
108
108
0.009
40
5.09
110
110
0.009
study for the AP pelvis
108
110
(25 mAs for a thickness
108
110
of 20 cm) and for the AP
lumbar spine (50 mAs
16
2.09
136
136
0.007
32
4.07
139
139
0.007
for a thickness of 25 cm)
136
139
136
139
were provided in a
separate document from
12.5 1.63
175
175
0.005
25
3.19
179
179
0.005
Fuji. The images for the
175
179
reference mAs and the
175
179
optimized mAs for the
8
1.06
277
277
0.003
20
2.56
220
220
0.004
AP pelvis and the AP
277
220
lumbar spine are shown
277
220
in Figures 2 and 3.
6.3 0.83
357
357
0.002
16
2.05
277
277
0.003
Image Quality
Assessment
The overall results
of the VGA study for
384
357
357
277
277
a
All images were obtained at 81 kVp.
The mean exposure index (EI) for 3 images obtained at each mAs setting.
c
Reference exposure techniques.
b
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
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Seeram, Davidson, Bushong, Swan
A
VGA scores as the dose decreases from 2.56 mGy
to 2.05 mGy (20-16 mAs). Figure 7 shows the mean
VGA scores plotted as a function of the mean EI. As the
EI increases, the VGA scores decrease. Again, this is to
be expected because for the Fuji CR system, the EI is
inversely proportional to the dose, meaning that as the
EI increases, the dose decreases.
B
Reference mAs (25)
Optimized mAs (16)
Figure 2. A comparison of image quality between the reference
image of the AP pelvis obtained at 25 mAs (A) and the optimized
image recorded at 16 mAs, or approximately one-third the reference dose (B). Images courtesy of the authors.
A
B
Reference mAs (50)
Optimized mAs (20)
Figure 3. A comparison of the image quality between the reference
image of the AP lumbar spine obtained at 50 mAs (A) and the
optimized image recorded at 20 mAs, or approximately one-third
the reference dose (B). Images courtesy of the authors.
1.63 mGy to 0.83 mGy (12.5-6.3 mAs, respectively).
Figure 5 shows the VGA scores plotted as a function of
the mean EI and demonstrates that as the EI increases,
the VGA scores decrease. This is to be expected
because for the Fuji CR system, the EI is inversely proportional to the dose, meaning that the EI increases as
the dose decreases.
The overall results of the VGA study for the lumbar
spine images are shown in Table 8, and Figure 6 shows
the VGA scores plotted as a function of the mean dose,
which demonstrates that the VGA scores increase
as the dose increases. There is a sharp decrease in
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
Discussion
The overall goal of this study was to determine the
lowest possible dose to the pelvis and lumbar spine of an
anthropomorphic phantom without compromising the
diagnostic quality of the images. To accomplish this goal,
3 sets of data were collected: dosimetry data, images, and
image quality assessments.
Dose is directly proportional to the mAs, meaning
that if the mAs is doubled, the dose doubles. For the
Fuji CR system, the EI (ie, the S number) is inversely
proportional to the dose1: as the dose increases, the EI
decreases proportionally. Thus, at 5 Gy, 10 Gy, and
20 Gy, the Fuji CR EIs are 400, 200, and 100, respectively.1 When the inverse EI is plotted as a function of
mAs and the dose is plotted as a function of the inverse
EI, the results show a strong positive linear relationship
in both cases (r  0.999).
The notion of an inverse EI (1/S for the Fuji CR system) is interesting, and perhaps instead of displaying the
S number on an image, the inverse S number should be
displayed. If this were the case, technologists might better
understand the relationship between dose to the patient
(as opposed to the image plate) and the S number because
as dose increases, the inverse S number (1/S) increases
proportionally.
To establish an optimum mAs and associated EI for
the pelvis and lumbar spine, it was important to first
produce images using the vendor’s recommended mAs
values. For a 20-cm thick AP pelvis, the recommended
or reference mAs was 25, which produced an EI of 86.
The mAs recommended by the vendor for a 25-cm
thick AP lumbar spine was 50, and this produced an EI
of 88. The optimized mAs selected by 7 expert observers for the AP pelvis was 16 mAs and 20 mAs for the
AP lumbar spine. These 2 mAs settings, the reference
and the optimized mAs, produced EI values of 136 for
the AP pelvis and 220 for the AP lumbar spine (see
Table 4). Unlike the vendor’s EI recommended ranges,
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Optimizing the Exposure Indicator as a Dose Management Strategy in Computed Radiography
AP Pelvis: Mean VGA Score vs EI
Lumbar Spine: Mean VGA Score vs Dose
Table
0.5 5
AP Pelvis and AP Lumbar Spine Image Acquisition Results
0.4
0.4
Observers
0.3
2
3
4
5
0.2
Pelvis
Image number selected
0.1
(reference mAs  25)
3
3
3
3
Mean VGA Score
1
Mean VGA Score
0.3
Body Part
0 Spine
Lumbar
43 54
69
Image number
selected
-0.1
(reference mAs  50)
0.2
3
86 23
108 136
23 175 23277 357
23
23
0.1
0.0
6
7
3
3
23
0
223
-0.1
Mean EI
-0.2
Table 6
-0.2
-0.3
AP Pelvis and AP Lumbar Spine Dose Measurement Results
-0.3
-0.4
4
Optimized
mAs
Dose
Reduction (%)
16
36
20
6
60
10
8
Mean Dose (mGy)
12
14
-0.5Part
Body
Reference mAs
(AP diameter)
EI for
Reference mAs
Optimized mAs
EI for
Optimized mAs
y 0.0377x 0.0821
R2 0.9576
Manufacturer’s
Recommended EI Range
Pelvis
25 mAs (20 cm)
86
16
136
250-600
20
220
250-600
Lumbar spine
50 mAs (25 cm)
88
AP Lumbar Spine: Mean VGA Score vs EI
0.4
Table 7
0.3 Grading Analysis (VGA) Scores for Images
Visual
Mean Dose
(mGy)
Mean EI
Mean VGA
Score
50
6.45
43
0.5
Mean VGA Score
0.1Setting
mAs
40
0
45
555.1770
32-0.1
4.14
25
b
88
54 139 1790.4220 277
110
0.4
Mean VGA Score
of an Anthropomorphic AP Pelvis Phantom
0.2
Compared
With a Reference Image at 25 mAsa
0.2
0.0
0.3
3.24
0.2
-0.4
20-0.2
2.60
108
0.2
-0.6
16
2.09
136
0
12.5
1.63
175
0
8
1.06
277
–0.2
6.3
0.83
357
–0.5
a
There were 7 observers, and 3 images were obtained for each mAs
setting at 81 kVp.
b
Reference exposure technique.
the optimized EI values do not fall within the range
of 250 to 600. To fall within this range, the mAs (and
associated EI values) would have to be 8 mAs (277) for
the pelvis or as low as 6.3 mAs (357) and 16 mAs (277)
for the AP lumbar spine.
386
0
1
-0.2
69 EI)
(Mean
86
-0.3
Pelvis: Mean VGA Score vs Dose (mGy)
0.6
2
3
4
Mean Dose (mGy)
5
6
7
y 0.1054x 0.1528
R2 0.9426
Figure 4. Visual grading analysis (VGA) scores plotted as a func-
tion of mean dose.
The optimized mAs values and optimized EI values
mean that all observers rated these 2 images as acceptable based on the lowest exposure used to produce
them. Images obtained with less than 16 mAs for the
pelvis and 20 mAs for the lumbar spine were deemed
unacceptable for diagnosis by all observers based on
the appearance of image mottle. These findings are
consistent with the results of the VGA study findings
that image quality is inferior (ie, negative VGA scores)
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
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Seeram, Davidson, Bushong, Swan
AP Pelvis: Mean VGA Score vs EI
0.5
Table 8
Lumbar Spine: Mean VGA Score vs Dose
0.4
VGA Scores for Images of an Anthropomorphic AP
0.4
Lumbar SpineAP
Compared
With
a Reference
Pelvis: Mean
VGA
Score vs EI Image
0.3
at0.5
50 mAsa
0.1
0
43
-0.1
54
69
86
108 136 175 277 357
0.3
1000.1
800.2
0.0
630.1 0
50-0.1
0
Mean EI
45
0.4
10
55
0.3
2 7.98 4
54
6.36
69
86
88
0.2
110
0.1
-0.5
2.56
220
–0.3
16-0.4
2.05
277
–0.3
3.19
55
2
70
4
88 110 139 179 220 277
6
8
10
12
14
(Mean
EI)
Mean Dose (mGy)
-0.2
-0.2
y 0.0377x 0.0821
R2 0.9576
-0.3
-0.3
Figure 6. The VGA scores plotted as a function the mean dose.
Mean VGA Score
Mean VGA Score
0.0
-0.1 0
-0.1
45
Mean VGA Score
277
0.0
-0.2
0
1
2
3
4
5
6
7
-0.2
Pelvis: Mean VGA Score vs Dose (mGy)
AP Lumbar Spine: Mean VGA Score vs EI
0.4
0.3
0.6
0.2
0.2
0.0
0.4
0.1
-0.2
0
0
-0.4
45
-0.1
-0.6
1
55
2
70
3
4
Mean Dose (mGy)
5
6
7
88
110 139 179 220 277
y 0.1054x 0.1528
(Mean EI) R2 0.9426
-0.2
0.2
0.0
-0.2
-0.4
-0.6
-0.3
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
Mean Dose (mGy)
-0.1
-0.3
Figure 7. Graphical display of the VGA scores plotted as a func-
for images of the AP pelvis obtained at 8 mAs and 6.3
mAs compared with the reference mAs of 25 (EI  86).
Image quality also
is inferior
forScore
the image
of(mGy)
the AP
Pelvis:
Mean VGA
vs Dose
0.6
lumbar spine obtained at 16 mAs compared with the
reference mAs of 50 (EI  88).
0.4 reference EI values obtained in this study for
The
the AP pelvis and AP lumbar spine and the optimized
0.2
EI values of 136 for the AP pelvis and 220 for the AP
0.0
There
-0.5 were 7 observers, and 3 images were obtained for each mAs
setting at 81 kVp.
b
Reference exposure technique.
0.3
0.2
0.1
0
0.1
a
0.6
0.4
0.2
0.1
Mean
139 EI y 0.0377x
0.1 0.0821
2
R 0.9576
179
0
4.07
Lumbar Spine: Mean VGA Score vs Dose
0.3
0.4
14
108 136 175 277 357
20-0.3
tion of the mean EI for the AP pelvis. As the EI increases, the VGA
scores (image quality)
decrease.
AP Lumbar
Spine: Mean VGA Score vs EI
0.4
0.3
0.2
10 0.2 12
-0.4
Figure 5. Graphical display of the VGA scores plotted as a func-
5.09
6 70 8
Mean Dose (mGy)
40
-0.1
-0.2
32
-0.2
25-0.3
-0.3
Mean
MeanVGA
VGAScore
Score
13
b
43
Mean EI
Mean VGA Score
mAs Setting
0.4
Mean VGA
Score
Mean VGA Score
0.2
-0.2
357
Mean Dose
(mGy)
0.4
0.2
VGA Score
Mean VGAMean
Score
Mean VGA Score
0.3
tion of the mean EI for the AP lumbar spine. As the EI increases,
the VGA scores (image quality) decrease.
lumbar spine do not fall within the vendor’s recommended values. One possible explanation might be
that the vendor’s recommended values were based on
patient exposures rather than on anthropomorphic
phantom exposures.
387
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Optimizing the Exposure Indicator as a Dose Management Strategy in Computed Radiography
However, the differences in the optimized EI values
found in this study and the vendor’s recommended EI
ranges for the pelvis and lumbar spine are not drastic.
Furthermore, Fuji states that the accuracy of EI values
falls within  20%.12 With this tolerance limit for the
optimized EI value for the AP lumbar spine, that is
 20% of 220 (176-264), only the upper limit of 264
falls within the vendor’s recommended range for the
lumbar spine of 250 to 600. Applying this tolerance
limit to the optimized EI (136) for the pelvis ( 20% of
136  110-163) would mean that the upper limit of 163
does not fall within the vendor’s recommended EI range
for the pelvis of 250 to 600.
However, these upper tolerance limits of EI values
for the pelvis and lumbar spine fall within the recommended limits for general adult imaging described by
Seibert based on the Fuji 5000 CR imaging system at
the University of California Davis Medical Center.23
Seibert reported that, assuming proper positioning and
using the correct processing algorithm matched to the
anatomy being imaged, the recommended S number
limits for an acceptable range are 150 to 300. The current study also used the Fuji 5000 CR imaging system,
and the optimized EI values obtained for the AP pelvis
and AP lumbar spine are closer to those reported by
Seibert.23 Furthermore, the optimized mAs of 16 for the
AP pelvis and 20 mAs for the AP lumbar spine resulted
in a dose reduction of 36% and 60%, respectively, compared with the doses obtained with the reference mAs.
Several points regarding the expert image assessment using the VGA procedure warrant further discussion. First, the overall VGA scores for the AP pelvis and
the AP lumbar spine showed the same general trend:
image quality improved with increasing dose (mAs)
and increasing inverse EI, using the fixed kVp and variable mAs exposure technique settings. This finding
also was more noticeable for the AP pelvis than for the
AP lumbar spine, with substantial to almost perfect
inter-rater reliability for the criteria numbers at specified mAs settings ranging from low to high. The goal
of the image quality assessment was to determine the
dose-image quality optimization using the mAs settings
and the visualization of specific structures at each of the
mAs settings in the range of settings used in this study.
Another important finding in the overall VGA scores is
clearly demonstrated in Figures 4 and 6, which show that:
388
 A threshold dose exists at which the VGA score
equals zero and visualization of anatomic structures
on test images is equal to visualization of the same
structures on the reference images. For the AP pelvis, this threshold dose is 1.63 mGy (12.5 mAs); for
the AP lumbar spine, it is 3.19 mGy (25 mAs).
 Below these threshold doses, VGA scores
decrease dramatically, meaning that visualization
of structures on the test images became more difficult and worsened compared with the visualization of structures on the reference images.
The second outcome of the image quality assessment was related to the VGA scores for the reference
and optimized mAs values. For the pelvis, the reference
and optimized mAs were 25 and 16, respectively; for
the AP lumbar spine, the reference mAs was 50 and the
optimized mAs was 20. The reference and optimized
VGA scores for the AP pelvis were 0.2 and zero, respectively, and they were 0.2 and 0.3, respectively, for the
AP lumbar spine. A positive VGA score meant that the
structures on the test images were better visualized
and reproduced compared with those on the reference
images, whereas a zero and a negative VGA score meant
that the structures visualized and reproduced on the
test images were equal to and worse than those on the
reference images, respectively.
For the AP pelvis, the optimized mAs of 16 resulted
in a VGA score of zero, signifying that the visualization
and reproduction of structures on an image obtained
at 16 mAs were equal to those on the reference image
obtained at 25 mAs. The result was a dose reduction
that upheld the ALARA principle (ie, image quality
was not compromised, and the dose to the patient was
reduced by 36%.)
For the AP lumbar spine, the optimized mAs of 20
resulted in a VGA score of 0.3. This meant the visualization and reproduction of anatomical structures on
an image obtained at 20 mAs were worse than those on
the reference image obtained at 50 mAs. This finding
suggests that the optimized 20 mAs is not acceptable
for dose-image quality optimization of the AP lumbar
spine. Table 8 shows that the dose-image quality in CR
imaging of the AP lumbar spine can be optimized and
the dose reduced to one-half the reference mAs (25 mAs)
because the VGA score at 25 mAs is zero. The dose for
the AP lumbar spine reference image obtained at 50 mAs
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
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Seeram, Davidson, Bushong, Swan
was 6.36 mGy, whereas it was 3.19 mGy for the image
obtained at 25 mAs. A score of zero indicated that visualization and reproduction of the structures on a test image
were equal to those seen on the reference image. Negative
and positive scores indicated that visualization and reproduction of structures on test images were worse or better
compared with those seen on the reference images. At
25 mAs, however, the cortex and trabecular patterns were
not reproduced and visualized clearly (ie, visualization
and reproduction were compromised).
Therefore, it is reasonable to examine visualization and
reproduction of structures at the next higher mAs setting
(32 mAs) and compare them with the reference 50 mAs
setting. All structures visualized and reproduced on the
32 mAs image were equal to those seen on the 50 mAs
reference image. No structure was compromised in terms
of visualization and reproduction. Therefore, it is logical
to select 32 mAs as the lowest mAs setting in the doseimage quality optimization strategy for the AP lumbar
spine. This would result in a dose reduction of 36% without compromising image quality.
The dose can be optimized at 16 mAs for the AP pelvis and at 32 mAs for the AP lumbar spine, resulting in
a dose reduction of 36% without compromising image
quality. The null hypothesis that there is no difference
between the main effects of mAs settings and criteria
number on criteria scores was rejected: image quality
improves as the dose increases, and a threshold dose
was found in which the structures on the test images
were equal in visualization and reproduction to the
same structures seen on the reference images. Finally,
below the threshold dose, image quality degrades.
The explanation for these findings is based on the
physics of quantum noise. Bushberg et al noted that imaging in the radiology department with ionizing radiation
“uses relatively few quanta to form the image—indeed
the numbers of quanta are so low that for most medical
images involving x rays…appreciable noise in the image
results, and this noise is quantum noise.”24 Noise affects
the visualization and reproduction of structures on an
image, and the “presence of noise reduces our ability to
extract information from an image.” 25
In dose optimization, the relationship between noise
in an image and radiation dose to the patient is a significant contributing factor. 4,24-26 In this study, the dose to
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
the patient was influenced by the range of low to high
mAs settings. By increasing the mAs, more photons are
distributed more uniformly at the detector, resulting in
a reduction of image noise.24,25 This reduction of image
noise resulted in better visualization and reproduction
of the anatomical structures assessed in the study.
The findings of this study show that the mAs and
its associated EI can be used as a radiation dose management strategy in CR imaging. The mAs can be
adjusted to an optimum value, resulting in a clinically
acceptable noise level that does not compromise image
quality. The user must understand how optimum mAs
levels can be established for various examinations.
Figures 8 and 9 summarize the main findings of the
VGA studies of the AP pelvis and AP lumbar spine.
The results of this study show it is feasible to optimize the dose and image quality in CR imaging using
the mAs exposure technique factor and associated
EIs for the Fuji CR system. Specifically, the dosimetry
phase of this investigation showed a strong positive
linear relationship (r  0.999) between mAs and dose,
mAs and the inverse EI, and the inverse EI and dose
for both the AP pelvis and AP lumbar spine. Under the
controlled conditions used in this study for dose optimization, the EI values were stable, unlike the results
reported by Butler et al.1
Furthermore, reference values of the manufacturer
of 25 mAs (EI  86) for the AP pelvis and 50 mAs
(EI  88) for the AP lumbar spine were optimized to
16 mAs for the AP pelvis (EI  136) and 32 mAs for
the AP lumbar spine (EI  139).
The third major finding determined by the image
quality assessment of 7 expert observers was that the
manufacturer’s recommended dose can be reduced by
36% for both the AP pelvis and AP lumbar spine without compromising image quality.
Conclusion
This study focused on dose optimization using a relatively new digital imaging technology in clinical practice.
This topic warrants continual scholarly inquiry as science
and technology for digital imaging systems advance.
Based on this study, an important future investigation
could be performed on the use of a standardized EI. The
wide range of EIs and detector exposures used by different
389
Peer Review
Optimizing the Exposure Indicator as a Dose Management Strategy in Computed Radiography
Figure 8. The main
findings of the VGA
study demonstrating
that the optimum mAs/
EI for the AP pelvis is
16 mAs/136 compared
with the manufacturer’s reference image
obtained at 25 mAs
and an EI value of 86.
Reprinted with permission from Seeram
E. The new exposure
indicator for digital
radiography. J Med
Imaging Radiat Sci.
2014;45(2):144-158.
Computed Radiography (CR) Image Noise and Image Quality
HIGH
ACCEPTABLE
LOW
LOW
OPTIMUM
HIGH
mAs/EI and Dose
CR Image Noise and Image Quality
Euclid Seeram, PhD, FCAMRT, is
honorary senior lecturer for the University of
Sydney, adjunct associate professor for Monash
University, adjunct professor for Charles Sturt
University, and adjunct associate professorFaculty of Health for the University of Canberra
in Australia. A founding member of the Journal
of Medical Imaging and Radiation Sciences,
he serves on editorial boards for Radiography,
Biomedical Imaging and Intervention Journal,
Open Journal of Radiology, International
Journal of Radiology and Medical Imaging,
LOW
OPTIMUM
HIGH
and Journal of Allied Health. He also
mAs/EI and Dose
serves on the international advisory panel for
Journal of Medical Radiation Sciences. His
Figure 9. The main findings of the VGA study demonstrating that the optimum
research interests are related to radiation dose
mAs/EI for the AP lumbar spine is 25 mAs/179 compared with the manufacturer’s
optimization in computed tomography and
reference image obtained at 50 mAs and an EI value of 88. Reprinted with permisdigital radiography imaging systems. He can be
sion from Seeram E. The new exposure indicator for digital radiography. J Med
reached at [email protected].
Imaging Radiat Sci. 2014;45(2):144-158.
Robert Davidson, PhD, FIR, is professor in
medical imaging for the University of Canberra
manufacturers of digital radiography imaging systems
in Canberra, Australia.
causes confusion among technologists.3 Therefore, a
Stewart Bushong, ScD, FAAPM, FACR, is professor
standardized EI is needed. Today, all digital radiography
of radiologic science for Baylor College of Medicine in
vendors offer the standardized EI; however, Seibert and
Houston, Texas.
Morin noted that “the nuances of this new exposure index
Hans Swan, PhD, is senior lecturer for Charles Sturt
standard are now at the beginning of clinical implementaUniversity, School of Dentistry and Health Sciences in
tion and testing.”27 Keeping this in mind, the logical next
Wagga Wagga, Australia.
step would be to extend this study to explore how radioReceived June 22, 2015; accepted after revision
logic technologists should implement the standardized EI.
September 10, 2015.
HIGH
390
ACCEPTABLE
LOW
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
Peer Review
Seeram, Davidson, Bushong, Swan
Reprint requests may be mailed to the American Society
of Radiologic Technologists, Communications Department,
at 15000 Central Ave SE, Albuquerque, NM 87123-3909,
or emailed to [email protected].
© 2016 American Society of Radiologic Technologists
References
1. Butler ML, Rainford L, Last J, Brennan PC. Are exposure
index values consistent in clinical practice? A multimanufacturer investigation. Radiat Prot Dosimetry. 2010;
139(1-3):371-374.
2. Uffmann M, Schaefer-Prokop C. Digital radiography: the balance between image quality and required radiation
dose. Eur J Radiol. 2009;72(2):202-208. doi:10.1016/j
.ejrad.2009.05.060.
3. Willis CE. Optimizing digital radiography of children. Eur J
Radiol. 2009;72(2):266-273.
4. Seeram E, Davidson R, Bushong S, Swan H. Radiation dose
optimization research: exposure technique approaches in CR
imaging: a literature review. Radiography. 2013;19(4):331338. doi:10.1016/j.radi.2013.07.005.
5. American Association of Physicists in Medicine. AAPM
Report No. 116: an exposure indicator for digital radiography. https://www.aapm.org/pubs/reports/RPT_116.pdf.
Published July 2009. Accessed November 24, 2015.
6. Fauber TL, Cohen TF, Dempsey MC. High kilovoltage
digital exposure techniques and patient dosimetry. Radiol
Technol. 2011;82(6):501-510.
7. Matthews K, Brennan PC. Justification of x-ray examinations:
general principles and an Irish perspective. Radiography.
2008;14(4):349-355. doi:10.1016/j.radi.2008.01.004.
8. Marshall NW. Optimisation of dose per image in digital
imaging. Radiat Prot Dosimetry. 2001;94(1-2):83-87.
9. Papp J. Quality Management in the Imaging Sciences. 4th ed.
St Louis, MO: Mosby; 2011.
10. American Association of Physicists in Medicine. AAPM
Report No. 31: standardized methods for measuring diagnostic
x-ray exposure. https://www.aapm.org/pubs/reports/RPT
_31.pdf. Published July 1990. Accessed November 24, 2015.
11. Sensitivity Testing [computer program]. Version V1.0 (B00).
Tokyo, Japan: Fujifilm Corporation; 2004.
12. Peters SE, Brennan PC. Digital radiography: are the manufacturers’ settings too high? Optimisation of the Kodak digital
radiography system with the aid of the computed radiography
dose index. Eur Radiol. 2002;12(9):2381-2387.
13. European Commission. European guidelines on quality
criteria for diagnostic radiographic images. EUR 16260 EN.
http://www.sprmn.pt/legislacao/ficheiros/European
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Guidelineseur16260.pdf. Published 1996. Accessed
November 24, 2015.
14. Sund P, Båth M, Kheddache S, Månsson LG. Comparison of
visual grading analysis and determination of detective quantum efficiency for evaluating system performance in digital
chest radiography. Eur Radiol. 2004;14(1):48-58.
15. Månsson LG. Methods for the evaluation of image quality: a
review. Radiat Prot Dosimetry. 2000;90(1-2):89-99.
16. Tingberg AM. Quantifying the Quality of Medical X-Ray
Images: An Evaluation Based on Normal Anatomy for Lumbar
Spine and Chest Radiography [dissertation]. Lund, Sweden:
Lund University; 2000.
17. Tingberg A, Sjöström D. Optimisation of image plate radiography with respect to tube voltage. Radiat Prot Dosimetry.
2005;114(1-3):286-293.
18. Geijer H, Persliden J. Varied tube potential with constant
effective dose at lumbar spine radiography using a flat-panel
digital detector. Radiat Prot Dosimetry. 2005;114(1-3):240-245.
19. Gorham S, Brennan PC. Impact of focal spot size on radiologic image quality: a visual grading analysis. Radiography.
2010;16(4):304-313. doi:http://dx.doi.org/10.1016/j.radi
.2010.02.007.
20. Båth M, Månsson LG. Visual grading characteristic (VGC)
analysis: a non-parametric rank invariant statistical method
for image quality evaluation. Br J Radiol. 2007;80(951):169176.
21. Båth M. Evaluating imaging systems: practical applications.
Radiat Prot Dosimetry. 2010;139(1-3):26-36. doi:10.1093
/rpd/ncq007.
22. Statistical Analysis System [computer program]. University
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23. Seibert JA. Computed radiography technology. In: Goldman
LW, Yester MV, eds. Specifications, Performance Evaluation,
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Publishing; 2004:153-174.
24. Bushberg JT, Seibert JA, Leidholdt EM, Boone JM. The
Essential Physics of Medical Imaging. 3rd ed. Philadelphia, PA:
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391
CE
Directed Reading
Medical Imaging of Neglected
Tropical Diseases of the Americas
Patrick Jones, BS, R.T.(R)
Jonathan Mazal, MS, R.R.A., R.T.(R)(MR)
Neglected tropical diseases
are a group of protozoan,
parasitic, bacterial, and
viral diseases endemic in 149
countries causing substantial
illness globally. Extreme
poverty and warm tropical
climates are the 2 most potent
forces promoting the spread
of neglected tropical diseases.
These forces are prevalent in
Central and South America,
as well as the U.S. Gulf Coast.
Advanced cases often require
specialized medical imaging
for diagnosis, disease staging,
and follow-up. This article
offers a review of epidemiology,
pathophysiology, clinical
manifestations, diagnosis (with
special attention to medical
imaging), and treatment of
neglected tropical diseases
specific to the Americas.
This article is a Directed
Reading. Your access to
Directed Reading quizzes
for continuing education
credit is determined by
your membership status
and CE preference.
After completing this article, the reader should be able to:

Define the term neglected tropical disease and discuss international interest in these
conditions.

Discuss neglected tropical diseases affecting the Americas including their pathophysiology, clinical manifestations, radiologic signs, diagnosis, and treatment.

Describe the need for the medical community to actively prevent continued spread of
neglected tropical diseases within resource-limited communities.
N
eglected tropical diseases
(NTDs) are a group of protozoan, parasitic, bacterial, and viral
diseases that are endemic in 149
countries and cause substantial illness for
more than 1.4 billion people globally.1
They are called neglected diseases
because they have been largely eradicated
in more developed parts of the world and
persist only in the poorest, most marginalized communities and conflict areas.
These diseases are contrasted with
HIV/AIDS, tuberculosis, and malaria,
which generally receive greater treatment
and research funding. One hundred percent of low-income countries are affected
by at least 5 NTDs simultaneously.1
In endemic countries, NTDs cause
impaired physical and cognitive development as well as illness and death,
killing an estimated 534 000 people
worldwide every year.1 Furthermore,
individuals often are afflicted with
more than one parasite or infection at
a time. Subsequently, related morbidity
and mortality, as well as contamination of potential farmland, results in
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
difficulty earning a living and limited
productivity in the workplace. These
conditions trap the poor in a cycle of
poverty and disease and cost developing economies billions of dollars annually. It is especially difficult to rationalize neglecting these conditions considering that the treatment cost for most
NTDs mass drug administration programs is estimated at less than $0.50
per person per year. The World Health
Organization (WHO) has prioritized
17 NTDs, and in May 2013, the 66th
World Health Assembly adopted resolution WHA66.12 that calls for intensified, integrated measures and planned
investments to improve the health
and social well-being of populations
affected by NTDs. WHO also has been
working with member states to ensure
implementation of the resolution.2
Impact in the Americas
The Americas comprise North
America, Central America, and South
America. The phrase “Latin American
and Caribbean region” can be used to
393
CE
Directed Reading
Medical Imaging of Neglected Tropical Diseases of the Americas
identify all countries within the Western Hemisphere
and south of the United States (see Figure 1).
The Latin American and Caribbean region has a
population of almost 600 million people, 3 of whom
an estimated 99 million live on less than $2 per day. 4
Approximately 10% of the region’s extremely poor live
in Bolivia, Ecuador, Nicaragua, and Venezuela.5 NTDs
are common wherever poverty is pervasive, and these 4
countries carry approximately 14% to 15% of regional
cases of Chagas disease, cutaneous leishmaniasis, dengue, and intestinal helminth infections. 6-10 Bolivia leads
in the number of Chagas disease cases (620 000) and
the number of children who require deworming for
intestinal helminth infections (3.4 million), whereas
Nicaragua leads in cutaneous leishmaniasis cases
(9000-14 800), and Venezuela has the largest number
of dengue cases (3.5 million). 6-8 Although Cuba is better off economically, it also has many cases of dengue
and intestinal helminth infections. 8-10 NTDs also are
widespread along the Gulf Coast states of Mexico
Figure 1. Map of the Western Hemisphere with Latin American
and Caribbean regions in blue. Image courtesy of Heraldry via
Wikimedia Commons. Licensed under the Creative Commons
Attribution-Share Alike 3.0 Unported license.
394
(Tamaulipas, Veracruz, Tabasco, Campeche, Yucatan,
and Quintana Roo) and in Chiapas and Oaxaca
on the southern Pacific coast. Mosquito-borne diseases are especially prominent with dengue incidence
rates increasing approximately 8-fold from 2000 to
2011, with peaks occurring in 2002, 2007, and 2009
(see Table 1).11
Extreme poverty and warm tropical climates are
the 2 most potent forces promoting the endemicity
of NTDs, and these same forces are widely prevalent
in the 5 states bordering the U.S. Gulf Coast: Texas,
Louisiana, Mississippi, Alabama, and Florida, with
10 million Gulf Coast residents living below the U.S.
poverty line.13 Thus, today the Gulf Coast is considered
North America’s most vulnerable and impoverished
region14,15 with high rates of NTDs emerging there
(see Table 2).15 In fact, the term emerging should be
used with caution because many of these NTDs are
not new to the region.16 Outbreaks of dengue were
reported in Texas from 2003-2005, with a return of the
disease in late 2013 affecting the poorest communities.17-19 In addition, dengue was reported in Florida in
2009 and 2010.20 The U.S. Gulf Coast also is considered vulnerable to the introduction of chikungunya, a
virus transmitted by Aedes mosquitoes that clinically
resembles dengue, with the possibility of year-round
transmission in the warm Gulf climate.21 Chagas disease transmission also has been confirmed in Texas and
Louisiana, 6,15,22 and a recent economic analysis revealed
that Chagas disease already incurs nearly $900 million
in costs in the United States.23
Some urgent needs in addressing NTDs include specific recommendations for greatly expanded disease surveillance and understanding of disease transmission.15,24,25
For many NTDs, diagnostic tests are cumbersome or not
widely available. One example is the lack of access to radiology services. Many advanced cases require specialized
medical imaging, and affected individuals must travel to
specialty clinics situated in more affluent communities, a
journey that often is not feasible.26 As of 1997, when data
was last collected, more than half of rural hospitals in
Latin America did not offer radiology services.27 For this
reason, a lack of awareness exists among health professionals regarding tropical disease management including
identification of radiologic manifestations.
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Table 1
Ranking of Neglected Tropical Diseases in Latin American Countries by Prevalence and Distribution12
Percentage of
LAC Population
Infected (% Poor
People Infected)
Disease
Population Currently
Infected in LAC
Main Vulnerable
Population at Populations or
Risk in LAC
Geographic Areas
No. of LAC
Countries
Infected
Trichuriasis
100 million
523 million
Poor rural &
urban slums
27
17.8 (46.9)
16.6
Ascariasis
84 million
514 million
Poor rural &
urban slums
27
15.0 (39.4)
10.4
Hookworm
50 million
346 million
Poor rural
26
8.9 (23.5)
8.7
Chagas disease
8 million-9 million
25 million90 million
Poor rural &
urban slums
13
1.6 (4.1)
99.8
Schistosomiasis
1.8 million
36 million
Poor rural
4 with  1000
cases
0.3 (0.8)
0.9
Blinding
trachoma
1.1 million
ND
Poor rural
3
0.2 (0.5)
1.3
Lymphatic
filariasis
720 000
8.9 million
Poor rural &
urban slums
7
0.1 (0.3)
0.6
Dengue
552 141 reported in
2006
ND
Urban slums
23
0.1 (0.2)
ND
Cysticercosis
400 000
75 million
Poor rural
15
 0.1 (0.2)
ND
Cutaneous (CL)
and visceral (VL)
leishmaniasis
62 000 CL
5000 VL
ND
Poor rural &
urban slums
18
Leprosy
47 612 new cases
ND
Poor rural &
urban slums
22
 0.1 ( 0.1)
11.4
Onchocerciasis
64 new cases in 2004
515 675
Poor rural
6
 0.1 ( 0.1)
0.3
Jungle yellow
fever
86 new cases in 2004
ND
Jungle &
urban slums
4
 0.1 ( 0.1)
 0.1
ND
Percent Global
Disease
Burden in LAC
ND
Abbreviation: LAC, Latin American Countries; ND, not determined.
Chagas Disease
Epidemiology
Chagas disease is caused by the parasite
Trypanosoma cruzi and is transmitted by triatomine
bugs.28 Chagas disease is recognized as one of the major
health problems in almost every Central and South
American country. Once a rural disease, Chagas disease
has become an urban phenomenon as a result of socioeconomic changes, rural exodus, deforestation, and
urbanization. Increases in immigration have resulted
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
in Chagas disease becoming a health care concern in
Europe and the United States as well. Furthermore,
2015 estimates from WHO indicate that 6 million to
7 million people are infected worldwide.28
Pathophysiology
The pathophysiology of Chagas disease is not entirely known. Sometimes referred to as the kissing bug, triatomine bugs transmit the T cruzi parasite when insect
feces enter an individual through an insect bite or skin
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Table 2
Main NTDs Affecting the Gulf of Mexico
16
Current
Status in
United Statesa
Current
Status in
Mexicoa
Vivax malaria
Nonendemic
Endemic
Dengue
Emerging
Endemic
West Nile virus infection
Endemic
Emerging
Chagas disease
Endemic
Endemic
Cutaneous leishmaniasis
Emerging
Endemic
Rickettsial infections
Endemic
Endemic
Soil-transmitted
helminth infections
Not determined
Endemic
Cysticercosis
Endemic
Endemic
Toxocariasis
Endemic
Endemic
Fascioliasis
Nonendemic
Endemic
Intestinal protozoan
infections
Endemic
Endemic
Leptospirosis
Sporadic or emerging
Emerging
Disease
Vector-borne NTDs
Helminthic NTDs
Other NTDs
a
Endemic is defined as being regularly found among a particular
people or in a certain area.
defect. Body parts particularly vulnerable to parasitic
transmission are the mucous membranes of the eyes or
mouth. Other routes of infection include consumption
of contaminated water or food, blood transfusions, and
organ transplantation.
Clinical Manifestations
Patients with acute Chagas disease usually have
characteristic inflammatory lesions at the site of T cruzi
entry called chagomas. Other early signs of the disease
include fever, headache, enlarged lymph glands, pallor,
muscle pain, difficulty breathing, abdominal or chest
pain, and purplish swelling of one eyelid called Romaña
sign (see Figure 2).28 As the disease progresses, the
3 organs predominantly affected are the esophagus,
colon, and heart. Dysphagia is the most common digestive symptom and results from abnormalities of esophageal motility with esophageal muscle contractions and
396
partial or absent relaxation of the lower esophageal
sphincter occuring simultaneously.29 In the late stages of
the disease, patients begin to experience megaesophagus and megacolon involving damage to submucosal
layers and the mesenteric nerve plexus. As a result,
megacolon patients can present with severe constipation for periods of 60 days or longer.30 Chagas disease
often affects the heart, resulting in epicardial ventricular tachycardia, 31 which can lead to sudden death.
Diagnosis
Gastrointestinal and cardiac symptoms accompanied with recent travel to Latin America would be suggestive of Chagas disease. Physical examination should
identify one of the following disease phases32:
■ Acute, nonspecific symptoms.
■ Asymptomatic and a significant chronic cardiac
disease.
■ Formation of digestive megaesophagus or megacolon.
To confirm diagnosis, laboratory tests might include
enzyme-linked immunosorbent assay (ELISA) serology
testing, a technique that uses the absorption of antibodies by insoluble preparations of antigens. Another option
for infectious disease diagnosis is polymerase chain reaction assays that amplify a few copies of a piece of DNA
across several orders of magnitude.33 In addition, histologic studies show that when host cells within parasitized
Figure 2. Romaña sign. Reprinted from Parasites – American
Trypanosomiasis (also known as Chagas disease). Centers for
Disease Control and Prevention Web site. http://www.cdc.gov
/parasites/chagas/. Updated July 19, 2013. Accessed April 9,
2015. Image courtesy of WHO/TDR.
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tissue rupture, trypomastigotes (a developmental stage of
T cruzi) are released and often can be detected by microscopic examination of anticoagulated blood.34
Dysphagia studies using fluoroscopy can exhibit a
measurable delay in digestive and swallowing movements as compared to normal esophageal motility.
These delays can affect the upper esophageal sphincter
and various stages of the swallowing process including
oropharyngeal transit, pharyngeal transit, and pharyngeal clearance. 34 Approximately 7% of Chagas disease
patients with megaesophagus develop esophageal
cancer (see Figure 3). Computed tomography (CT)
can demonstrate the extent of such tumors, detecting
mediastinal and nodal involvement, and it can be used
to confirm cases of mediastinitis and esophageal perforation. 35
Chest radiography is an important and inexpensive
tool used to identify patients with dilated cardiomyopathy secondary to Chagas disease. Calcifications in the
apical vasculature often are a radiologic manifestation
of this condition. 33 CT, as well as ultrasonography, magnetic resonance (MR) imaging, scintigraphy, and angiography, enable evaluation of infarcts resulting from
chronic Chagas heart disease. 35 When advanced imaging capabilities are available, noncontrast multidetector
electrocardiography-gated CT scanning for calcium
scoring is the protocol of choice, followed by contrastenhanced CT coronary angiography for examining
Chagas disease–associated infectious myocarditis. 36
Cardiac MR imaging studies have shown that both
myocardial fibrosis and segmental cardiac wall motion
abnormalities were associated with ventricular arrhythmia in patients with chronic Chagas heart disease. Even
in patients with this condition who have preserved or
minimally impaired ventricular function, the arrhythmogenic substrate can be present. Myocardial fibrosis
detected on cardiac MR is the most important variable
associated with ventricular arrhythmia.37
Treatment
Chagas disease is curable if treated in the acute
phase.32 Surgery is a treatment option for megacolon
secondary to the disease and can consist of either the
Duhamel-Haddad or the Habr-Gama procedures,
which result in similar final configurations involving
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A
B
Figure 3. Anterolateral (A) and lateral (B) chest projections
showing megaesophagus as a result of Chagas disease in a man
with development of cancer in the distal third of the esophagus
with perforation forming a large abscess that extends into the right
lower lobe and pleural space. Reprinted from Palmer P, Reeder M.
The Imaging of Tropical Diseases [DVD]. The International
Society of Radiology Web site. http://www.isradiology.org/
tropical_deseases/tmcr/chapter4/esopha gus6.htm. Accessed
December 17, 2015.
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rectalsigmoidectomies of all, or almost all, of the dyskinetic rectum.38 Most patients with Chagas disease have
some form of heart disease, and this must be considered
when determining the level of risk in surgical intervention.32
To cure patients of parasitemia from Chagas disease,
the prescribed medication is either benznidazole or
nifurtimox. These 2 medications destroy the T cruzi parasite.39 In the United States, these antiprotozoal agents
are not U.S. Food and Drug Administration approved
and are available only from the Centers for Disease
Control and Prevention (CDC) under investigational
protocols.40 The main contraindications to these treatment options are pregnancy, neurologic and psychiatric
conditions, and existing kidney or liver failure.
Preventive measures involve spraying insecticides
and improving housing to increase hygienic living conditions because no vaccination solutions are available
for Chagas disease. 41
Cysticercosis
Epidemiology
Cysticercosis is an infection caused by a helminth (parasitic worm), specifically the tapeworm, Taenia solium. It is
found worldwide and is endemic in most Latin American
countries, most often in rural areas where hygiene practices are poor. As a result of increasing immigration, numbers of patients with cysticercosis are rising in countries
where local transmission typically is low. The prevalence
of neurocysticercosis, which occurs when larvae reach
the brain, is 0.2 to 0.6 per 100 000 inhabitants in some
western states of the United States, and it is diagnosed in
more than 2% of patients visiting emergency departments
for seizures.42
Pathophysiology
Taenia solium has a 2-host life cycle between
humans and pigs. Only humans can serve as a host
for adult tapeworms, whereas both pigs and humans
can serve as intermediate hosts for the larval form.
Oncospheres, or tapeworm embryos, are passed to
the environment in human feces, which in settings
of poor sanitation and free-roaming animals can
be ingested by pigs. After ingestion, the embryos
hatch and actively cross the intestinal mucosa to the
398
bloodstream, providing access to the liver, eyes, central nervous system, and striated muscle, where they
develop into cysticerci, larval tapeworms enclosed
within a sac. Pigs with cysticercosis become intermediate hosts, and the disease lifecycle is completed
when undercooked pork infected with cysts is consumed by humans. 43,44 After cysts are ingested by
humans, the scolex, or tapeworm head, turns inside
out, attaches to the intestinal wall, and in 2 months
matures into a 2-m to 4-m ribbon-like tapeworm.
Cysticercosis infections usually cluster around tapeworm carriers, meaning person-to-person spreading
of the disease is likely to be the predominant means of
human contamination vs contamination through environmental sources. 45-47 Individuals infected with tapeworms spread T solium eggs indirectly through poor
hygiene practices such as lack of hand washing and contaminated food, water, or surfaces. Affected individuals
can be reinfected with larvae produced by tapeworms
already in the body.
Clinical Manifestations
Acute cysticercosis outside of the central nervous
system usually is not associated with clinical manifestations, with the exceptions of ocular involvement and
rare cases of massive muscular involvement. It can be
months or years after initial infection before symptoms
of chronic infection manifest, and these symptoms are
dependent on the location and number of cysts in the
body. When the cysts die, the surrounding tissue swells,
increasing pressure and inducing symptoms. Cysts in
muscle tissue might develop into palpable, sometimes
tender, subcutaneous masses. Cysts in the eyes can float
in the vitreous humor, disturbing vision and potentially
swelling, causing detachment of the retina. Recurrent
seizures occur in approximately 80% of symptomatic
cases of neurocysticercosis, making epilepsy the most
common neurologic manifestation48 and neurocysticercosis one of the most important causes of seizures in
the world. 49 Other neurologic symptoms include focal
deficits (16%), increased intracranial pressure (12%),
and cognitive decline (5%).48 In fact, neurocysticercosis
is regarded as “the great imitator” because it can mimic
almost any neurological disorder including isolated
headaches, stroke, or involuntary movement. 43,50-52
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Diagnosis
Histological confirmation of the parasite is not
possible in most neurocysticercosis cases because of
complications from inflammatory response or effects
of prior medications. Diagnosis usually is based on
neuroimaging and confirmed by serological testing
via enzyme-linked immunoelectrotransfer blot assays,
which use lentil-lectin purified glycoprotein antigens
to detect T solium antibodies. Enzyme-linked immunoelectrotransfer blot sensitivity is approximately 98%,
meaning patients with more than one viable cyst will
have a positive serology, and a negative serology result
should lead to investigation of alternative diagnoses.53
Detection of anticysticercal antibodies in the cerebral
spinal fluid by ELISA is 89% sensitive and 93% specific
in patients with viable neurocysticercosis infections and
is used when enzyme-linked immunoelectrotransfer
blot is not available.54 Antibodies to T solium frequently
are reported in the asymptomatic general population in
endemic regions, suggesting prior or current exposure
to the parasite.
Radiologic confirmation of cysticercosis can be completed with radiography or ultrasonography, although
it typically is limited to late disease identification when
cysticerci are more distinguishable. Soft tissue radiography commonly demonstrates multiple (often several
hundred) calcifications. These calcifications appear
either linear or oval and measure 4 mm to 10 mm or
more in length and 2 mm to 5 mm in width. Moreover,
calcified cysts have their long axes in the plane of the
surrounding muscle bundle (see Figure 4).
On chest radiography, cysticerci might be seen in
the lungs with measurements of about 3 mm to 6 mm
in diameter. The outer shells of the lesions are calcified,
with somewhat lighter and softer centers, and remain
more rounded when compared with the oval calcified
cysts found in muscle.35
Ultrasonography is particularly useful in examining cysticercosis of the eye and extraocular muscles. In
examinations of the orbit, as well as other soft tissue
and musculoskeletal structures, the primary diagnostic
features are oval or round well-defined cystic lesions
with an eccentric echogenic scolex within them. In
cases of calcified cysticercosis, ultrasonography demonstrates multiple calcifications in soft tissue similar to the
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Figure 4. Cysticercosis of the lower extremity. Reprinted from
Palmer P, Reeder M. The Imaging of Tropical Diseases [DVD].
The International Society of Radiology Web site. http://www
.isradiology.org/tropical_deseases/tmcr/chapter7/clinical2a.htm.
Accessed December 17, 2015.
pathognomonic millet seed-shaped elliptical calcifications in soft tissue described on radiography.55
In regions where CT and MR are available, these
scans can provide information on the morphology and
localization of cysticercosis cysts, burden of infection,
stage of the cysts, and surrounding inflammation. The
appearance of parenchymal brain lesions on neuroimaging indicates their stage of shrinkage and can be used to
monitor the effectiveness of treatment regimens. Live
vesicular cysts are small, rounded lesions with little or
no pericystic edema; they do not enhance with contrast. The cysts frequently show the tapeworm scolex
as an internal asymmetric nodule (ie, a hole-with-dot),
and several viable cysts showing scolices confirm the
diagnosis. Calcified cysticerci are clearly visible on CT
as nonenhancing hyperdense nodules, also without
peripheral edema. The degenerative process becomes
apparent when colloid cysts with poorly defined borders
are surrounded by edema and show a marked ring or
nodular contrast enhancement. MR diffusion-weighted
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imaging and apparent diffusion coefficient maps might
allow visualization of the scolex in colloidal cysticerci,
which are seldom visible on CT or conventional MR
sequences. 56,57 In rare cases in which a solitary degenerating cyst is present, misleading differential diagnoses
can lead to unnecessary biopsies. For example, neurocysticercosis and tuberculosis often are encountered in
low-income regions of the world and have some similar
clinical and radiological features. Thus, diagnostic criteria have been validated to differentiate these entities
in patients with one brain nodule on the basis of size,
edema, and clinical presentation (see Figure 5). 58
Treatment
Therapy can include symptomatic therapy, antiparasitic treatment, or surgery (eg, lesion resection or shunt
placement) and often requires a combination of these
options. Advantages of medical therapy include treating surgically unreachable and multifocal cysticercosis.
Therapy planning depends on proper characterization
of the neurocysticercosis type, location, and level of
brain involvement. Surgery is considered only when a
diagnosis is in doubt or the infection is clinically progressive. 43
The International Task Force for Disease
Eradication has targeted T solium infection for focal
elimination and eventual eradication. 59 Furthermore,
field control efforts have been attempted since 1987 in
Latin American countries including Ecuador, Mexico,
Peru, Guatemala, and Honduras. 60,61 Preventive measures recommended by the CDC include good hand
washing hygiene using soap and warm water after bathroom use and changing diapers and before handling
food. Proper food and water consumption practices
involve washing and peeling all raw vegetables and
fruits before eating, drinking only bottled or boiled
water and bottled drinks, and filtering and dissolving
iodine tablets into water when traveling within developing countries. 44
Echinococcosis
Epidemiology
One of the oldest known diseases is hydatid disease,
also called human cystic echinococcosis. 62 Today, this parasitic disease is the most serious and widespread human
400
A
B
C
D
E
F
Figure 5. Magnetic resonance imaging of human neurocysticer-
cosis. A. Viable cysts. B. Enhancing nodule. C. Brain calcifications. D. Parenchymal neurocysticercosis. E. Basal subarachnoid
neurocysticercosis. F. Intraventricular cysticercosis. Reprinted
from The Lancet Neurology, Vol. 13. Garcia HH, Nash, TE,
Del Brutto OH. Clinical symptoms, diagnosis, and treatment of
neurocysticercosis. 12012-1215.Copyright 2014, with permission
from Elsevier.
flatworm infection in the world, 63 affecting more than
1 million people and costing $3 billion annually in
clinical treatments and livestock compensation. 64 The
disease has 2 predominant forms: alveolar and cystic.
Alveolar echinococcosis is not commonly found in the
Americas, whereas cystic echinococcosis can be found
in Central America, South America, and in rare cases,
North America.
Pathophysiology
Cystic echinococcosis is zoonotic (ie, transmissible
from vertebrate animals to humans), 65 and the transmission cycle begins when dogs eat meat infected with
cysts that grow into adult tapeworms (Echinococcus
granulosus). The dogs eventually shed tapeworm eggs
in their feces, contaminating the soil. Sheep subsequently consume the eggs and develop parasitic larva
in their viscera. The cycle affects humans when they
consume water or food that has been contaminated by
dog fecal matter, 64 thus sheep farmers are more likely
to develop hydatidosis because their flock often acts as
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an intermediate host. The risk of farm animal infection is high in these environments
because E granulosus eggs can remain viable
for up to a year. 66 Once ingested by humans,
the eggs enter a larval stage resulting in hydatid, or larval, cyst formation (see Figure 6).
6
1
4
5
2
Clinical Manifestations
2
4
Infected individuals often are asymp4
tomatic until the hydatid cysts grow large
4
enough to cause discomfort, pain, nausea,
4
4
and vomiting. The cysts will grow for several
4
years before reaching maturity, and symptom
3
3
development depends on the cysts’ location.
65
A majority (50%-70%) develop in the liver,
but they also can occur in the lungs, spleen,
kidneys, heart, eyes, and skeletal and central
nervous systems. Trauma to an infected
Figure 6. Life cycle of Echinococcus granulosus. Public domain image
person can result in cyst rupture causing cystic
courtesy of the Centers for Disease Control and Prevention.
fluid and daughter cysts to be released into surrounding tissues, potentially exerting pressure
Ultrasonography can provide multiple imaging
on adjacent organs. When this happens, patients
planes for optimized diagnosis of hydatid cysts. Used
might have a high fever and become severely ill.
exclusively or in combination with laboratory tests,
They might also experience anaphylaxis, demonstratradiography and ultrasonography can allow for an
ed by a range of complications from urticaria (hives)
almost 100% positive diagnosis of hydatid disease in
to life-threatening circulatory shock. 67
the majority of cases.35 Using ultrasonography, cysts
Diagnosis
initially were categorized via the Gharbi classification in
A patient presenting with a cyst-like mass and a his1981, a system widely used but in modified forms. The
tory of recent exposure to sheepdogs while in an area in
Gharbi classification is as follows35,65,69:
which E granulosus is endemic is suggestive of cystic echi Type I – pure fluid collection.
nococcosis. Laboratory tests such as indirect fluorescent
 Type II – fluid collection with a split wall.
antibody, immunoelectrophoresis, ELISA serology, and
 Type III – fluid collection with septa.
radioallergosorbent tests can confirm diagnosis.35,68
 Type IV – heterogeneous echo patterns.
In most instances, radiography is used for initial
 Type V – reflecting thick walls.
screening. In positive cases, an unruptured hydatid cyst in
The cyst classification process also was dependent on
the lung presents as a homogenous round or oval-shaped
information related to the size, number, and localization
mass with smooth borders surrounded by healthy lung
of the cysts and any associated complications. 65 In 2003,
tissue. Many times this will be an incidental finding,
WHO proposed a standardized classification based on
with the radiography ordered for an unrelated condition.
the active-transitional-inactive cyst status as indicated
Ruptured cysts are more common in lung tissue than liver
by ultrasonography (see Table 3).70
tissue because of a higher incidence of bronchial rather
Contrast-enhanced CT (CECT) also is an effecthan biliary patency through the cyst.35 If a cyst ruptures
tive modality for diagnosing cystic echinococcosis.
in the lungs, radiologic signs include the “double arch” or
The “air bubble” sign, caused by air trapped within a
“cumbo” sign, and the “air bubble.” 68
cyst, can provide significant statistical results (85.7%
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Table 3
World Health Organization Classification of Cystic Echinococcosis Cysts and Imaging Features71
Classification
Clinical Group
Ultrasonography Imaging Features
Cystic lesion
Group 1: Active group: cysts developing and are
usually fertile
Unilocular, with uniform content, cyst wall not visible
CE1
Unilocular, simple cyst with visible cyst wall
CE2
Multivesicular, multiseptated cysts; cyst septations produce
“wheel-like” structures, and the prescence of daughter cysts
is indicated by “rosette-like” or “honeycomb-like” structures
CE3
Group 2: Transition group: cysts starting to degenerate, but usually contain viable protoscoleces
Unilocular cyst that might contain daughter cysts; detachment of laminated membrane; “water-lily” sign
CE4
Group 3: Inactive group: degenerated or partially
or totally calcified cysts; very unlikely to be fertile
Heterogeneous content, “ball of wool” sign, which is
indicative of degenerating membranes
CE5
Thick calcified wall
Abbreviation: CE, cystic echinococcosis.
sensitivity and 96.6% specificity). A hydatid cyst is
viewed optimally in the mediastinal window as a
single or multiple small, rounded radiolucent area
with specific margins in the outer portion of a solid
mass lesion. An infected cyst also will produce higher
attenuation values ( 20 HU), appearing brighter
when compared with unruptured cysts. The density
of an infected cyst can be problematic when differentiating it from an abscess or neoplasm. However,
follow-up CECT scans can be useful in determining
the presence of an “empty cyst” sign, an indication
that contents were completely expectorated. 68 Unless
infection produces gas, premature death of the cyst
and infection have the same appearances on CT and
ultrasonography. In both cases, the fluid component
becomes echogenic on ultrasonography and denser on
CT, and there is an overall loss of clarity of the lesion’s
internal detail. 35
Treatment
Cystic echinococcosis can be expensive and complicated to treat, sometimes requiring extensive surgery,
prolonged drug therapy, or both. 64 Today, the accepted
form of treatment is an image-based and stage-specific
approach.71 Options for management are64:
■ Percutaneous treatment of the cysts with puncture, aspiration, injection, and re-aspiration
(PAIR technique).
402
■Surgery.
■ Anti-infective drug regimen.
■ Expectant management, or watching and waiting
with medical imaging surveillance.
Surgery remains the preferred treatment for liver
cystic echinococcosis65 and often can lead to a cured
status, whereas treatment with a drug therapy of albendazole or mebendazole decreases the risk of disease
recurrence and intraperitoneal seeding of infection that
might develop with cyst rupture.72 Some cysts can be
asymptomatic and remain inactive. These often disappear without treatment; therefore, watching and waiting can be beneficial. 65
Foodborne Trematodiases
Epidemiology
Foodborne trematodes (flatworms or “flukes”) in the
larval stage enter a host when they are ingested as part of
a contaminated meal. These infections are particularly
prevalent in East and Southeast Asia, and in Central and
South America. The WHO estimates that 40 million
people have these types of infections.73 Most of these
infections are mildly pathogenic, but several are severe
including clonorchiasis, opisthorchiasis, paragonimiasis,
and fascioliasis. Of these, only paragonimiasis and fascioliasis are known to affect people in the Americas.74
Paragonimiasis infections are transmitted by freshwater shellfish within the Western Hemisphere.74
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Various species, including Paragonimus mexicanus, Paragonimus ecuadoriensis, and Paragonimus
kellicotti, have affected humans in Canada
and Central and South America, especially
Colombia, Ecuador, Peru, Venezuela, and parts
of Brazil, as well as Costa Rica, Honduras, and
Mexico. 35 In contrast, fascioliasis, which is
caused by the parasite Fasciola hepatica, is prevalent in sheep- and cattle-raising areas of South
America,74 with worldwide infection estimated
to exceed 2 million.1
5
4a
4b
4c
6
4
7
3
8
Pathophysiology
The life cycle of Paragonimus strains begins
when the unembryonated eggs are released into
fresh water by infected humans via unsanitary
practices regarding their mucus or stool.1 While
2
in the fresh water, the eggs become embryo1
nated and hatch into miracidia (larvae) that
infect snails, their primary host. Within the
Figure 7. Life cycle of Paragonimus strains. Public domain image courtesy of
snail, the miracadia undergo several changes
the Centers for Disease Control and Prevention.
and leave the snail as cercariae that then infect
a secondary host of crustacean crabs and crayfish, enclosing themselves within metacercariae
intestines, peritoneal cavity, and liver to reach the biliary
(soft tissue cysts). Humans become infected following
ducts where they become adult flukes.1
consumption of raw, undercooked, or pickled freshwaClinical Manifestations
ter shellfish containing the metacercariae. The parasite
Clinical signs of paragonimiasis are from mechanithen exits its cystic stage to penetrate the human host’s
cal damage caused by the migration of the worm from
peritoneum and lungs. Once settled, the trematodes
the gut to the lungs. In some instances, the flukes can
develop into adult flukes in 2 months (see Figure 7).74
migrate in the host ectopically to the brain or subcuIn contrast, fascioliasis involves development of
taneous sites of the extremities.5 When the parasite
F hepatica following consumption by sheep and cattle
reaches the lung, the most common site of infection, it
where they grow into adult flukes, specifically in the
causes hemorrhaging, inflammatory response, necrosis
bile ducts of the infected mammals. These animals then
of lung parenchyma, and fibrotic encapsulation. Acute
introduce immature F hepatica eggs in their feces to a
paragonimiasis is demonstrated by a cough, abdominal
freshwater environment. Similar to Paragonimus strains,
pain, discomfort, and low-grade fever that can occur 2
the eggs embryonate and hatch in the water after several
to 15 days after infection.1 A person with chronic pulweeks as the miracidium that infects a snail host. After
monary paragonimiasis has a cough producing brown
several more weeks, the parasites emerge from the snail
and blood-streaked pneumonia-like sputum. The
as cercariae; however, they select water plants to encyst as
hemoptysis typically is induced by strenuous work, and
metacercariae. Humans become infected following conthe coughing often can be confused with chronic bronsumption of contaminated plants, especially watercress.
chitis or bronchial asthma.75
The maturation of the parasite in the human host can take
In contrast, symptoms in the acute phase of fascioapproximately 3 to 4 months. During this time, the metaliasis can correspond with the parasite’s migration from
cercariae exist in the duodenum and travel through the
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the intestine to and through the liver. Symptoms can
include nausea, vomiting, and abdominal pain or tenderness. In addition, fever, rash, and difficulty breathing can occur in acute cases.1 When the fluke reaches
the liver, hepatomegaly occurs as the migratory flukes
destroy liver parenchyma. Chronic fascioliasis is associated with the presence of adult worms in the bile ducts
of the host. At this stage, symptoms can be difficult to
distinguish from other hepatic diseases such as cholangitis, cholecystitis, and cholelithiasis.75
Diagnosis
Diagnosing paragonimiasis involves analysis of patient
sputum, stool, and biopsies, as well as medical imaging.74
To overcome the low sensitivity of egg detection tests
and low specificity of intradermal tests, serological testing, such as ELISA, is used to measure the serum levels
of antibodies and has been found by the CDC to have a
sensitivity and specificity greater than 95%.74
In people suspected of having a paragonimiasis
infection, chest radiographs show abnormalities of the
lungs or pleura similar to tuberculosis including infiltrates, nodules, cavities, and fibrosis. Evaluation of the
radiographs is based on the migration of the flukes.
Once the flukes penetrate the lung, hemorrhagic and
exudative pneumonia occurs around them, and 2-mm
to 4-mm thick and 2-cm to 7-cm long band-like opacities adjacent to the pleura representing worm migration tracts or peripheral atelectasis are commonly
seen. 35
Better-defined nodules or thin-walled cysts appear
on medical imaging if flukes remain in the same position because surrounding airspace consolidation can
occur. In patients with airspace consolidation without
visible cysts on radiographs, a CT scan with intravenous
contrast can highlight cysts within the consolidated
lung because of the difference of the darker (lower
attenuation) fluid-filled cysts compared with brighter
adjacent consolidated lung. Once lytic cysts extrude
intracystic fluid, a CT scan might show them as airfilled cysts within the consolidated lung. 35 The most
characteristic radiographic feature of the mature stage
of paragonimiasis is the “solar eclipse” sign, which has
been seen in up to 82% of patients in chest radiography
and chest CT scans. These ring shadows represent the
404
thin-walled borders of cystic cavities, with a crescentshaped opacity along one side of the border appearing
like the corona of a solar eclipse. This feature represents
worms attached to the wall of a cyst (see Figure 8).35
Similarly, in fascioliasis-endemic areas, examining
stool samples for evidence of parasitic eggs can be performed; however, serologic diagnosis using F hepatica
excretion-secretion antigens and ELISA testing has
been more effective. The indirect hemaglutination test,
a suspension that binds red blood cells, has a 100%
diagnostic sensitivity and 97% specificity, if the metabolic antigen is used.35 In addition, testing the blood for
high eosinophil levels has been effective in up to 68% of
individuals with severe fascioliasis infections. Although
laboratory tests help with diagnosis, serologic assays are
limited because they cannot distinguish between past
and current infection.74
CT and ultrasonography have become widely available in endemic areas to assist with diagnosing fascioliasism.35 When using CT to assess an infected liver,
imaging shows hypodense migratory lesions.74 These
nodular intrahepatic lesions present with diminished
attenuation, ranging in size from 4 mm to 10 mm
but sometimes as large as 2 cm. Intravenous contrast
medium might allow definition of these lesions on
dynamic and delayed scans (see Figure 9). These
Figure 8. Pulmonary paragonimiasis. High resolution CT image
showing the “solar eclipse” effect indicating worm cysts (arrow). A
right-sided pneumothorax and worm cyst appear in the posterior
right lung. Reprinted from Palmer P, Reeder M. The Imaging of
Tropical Diseases [DVD]. The International Society of Radiology
Web site. http://www.isradiology.org/tropical_deseases/tmcr
/chapter22/radiological4b.htm. Accessed December 17, 2015.
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A
B
Figure 9. A computed tomography (CT) scan of a patient with fascioliasis. A. Hypodense nodular lesions in the right lobe of the liver
(arrows). B. CT scan at lower level shows hypodense tortuous channels and nodular lesions in the periphery of the right lobe and slight ectasia of bile ducts. Contrast enhancement of a thickened liver capsule is seen (arrowhead). Reprinted from Palmer P, Reeder M. The Imaging
of Tropical Diseases [DVD]. The International Society of Radiology Web site. http://www.isradiology.org/tropical_deseases
/tmcr/chapter21/otherfas4.htm. Accessed December 17, 2015.
nodular lesions, which correspond to microabscess
formation and can occur in clusters, are difficult to differentiate from necrotic neoplasms or other abscesses.
If peripheral, convoluted lesions or channels are present
in a patient from an endemic region, hepatic fascioliasis
becomes the primary consideration. These convoluted
channels can be seen during surgery and laparoscopy
and in many instances are identified as migratory tracts
left by the flukes. 35
Often, the small cystic lesions calcify after treatment. Performing CT scans to follow up with fascioliasis
patients helps document response to treatment. Biliary
duct dilatation and irregular wall thickening are thought
to be better demonstrated on ultrasonography. The nonspecific round nodular lesions of hepatic fascioliasis can be
viewed with ultrasonography as lesions of variable echogenicity. However, the characteristic convoluted channels
of fascioliasis are less identifiable on ultrasonography,
and therefore CT is the preferred cross-sectional imaging
modality for the hepatic form of this disease.35
Treatment
Treatment for paragonimiasis entails a short course
of oral praziquantel 3 times a day for 3 days,73 which
has an efficacy rate of at least 90%.76 Praziquantel is
an anthelmintic, meaning it is used to treat worm
infections, and works by inducing severe spasms and
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
paralysis of the worm’s musculature. The worm is then
either destroyed in the intestines or passed whole in
the stool.77 When treating cerebral paragonimiasis, praziquantel should be administered in combination with
corticosteroids.74
Fascioliasis differs from other fluke infections in that
it does not respond well to treatment with praziquantel.
The most effective treatment is triclabendazole, another
anthelmintic. This medication can be difficult to access
in the United States; it is available only through the
CDC under a special (investigational) protocol.1 The
cure rate for the disease is approximately 80% after
taking 1 or 2 oral doses of the drug. Repeat dosing is
required if abnormal radiologic findings or eosinophilia
do not resolve.74
Onchocerciasis
Epidemiology
Onchocerciasis, often referred to as river blindness,
is a parasitic disease caused by the filarial worm,
Onchocerca volvulus. Onchocerciasis is an eye and skin
disease transmitted to humans through the bites of
infected black flies in the family Simuliidae, which
breed in environments that have fast-flowing rivers
and streams.78 Onchocerciasis is the world’s fourth
leading cause of preventable blindness, with the parasitic disease threatening the health of approximately
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25 million to 125 million people worldwide. Although
99% of those affected by onchocerciasis live in Africa,
approximately 500 000 people in the Americas also are
at risk.78-80 It is believed that onchocerciasis was brought
to the Western Hemisphere through slave trade in the
Americas and spread through migration.80 The greatest risks within the Americas region have been isolated
to 13 foci of infection throughout Brazil, Colombia,
Ecuador, Guatemala, Mexico, and Venezuela.80
Pathophysiology
People who live in remote villages near rivers have the
greatest susceptibility for black fly bites. Once the O volvulus parasite is transmitted to the human host, the infectivestage larvae molt twice and mature into adult worms
within nodules under the skin. These nodules are referred
to as onchocercomas. At this point, the adult worms begin
to reproduce, creating millions of larvae (microfilariae).80
Clinical Manifestations
The infective activity of onchoceriasis can be differentiated by that of microfilariae and of adult worms.
The most significant activity pertains to the wandering microfilariae, which can result in groups as high as
2000 larvae/mg of skin. In the infected host, microfilariae are found in all layers of skin, but are most concentrated within the dermal papillae.35 Histopathology of
onchocercomas demonstrate that the nodules are firm
and have 3 separate layers4:
■ An outer fibrous layer of granulation and scar tissue.
■ A middle layer of inflammatory cells.
■ A central soft core that contains adult nematodes
surrounded by an amorphous, eosinophilic, hyaline material named Splendore-Hoeppli material.
Symptoms of an onchoceriasis infection are caused
by the migration of the microfilariae and include
intense itching, rashes, disfiguring skin lesions
(referred to as leopard or lizard skin), and eye disease
that can result in blindness.79 Although the most
severe infections occur in the skin and eyes, lymph
nodes also are commonly affected.79 Onchocercal
dermatitis is inflammatory and progressive, leading
to fibrosis and replacement of healthy skin. Changes
in skin thickness, pigmentation, edema, and scarring
of the epidermis are key indicators of this disease.
406
Dermal elastic fibers are lost gradually, resulting in
abnormally wrinkled skin. 35
Evaluation of visually impaired patients involves
assessing the amount of microfilaria in the cornea and
the anterior chamber of each eye. Assessment also is
performed for other conditions that might result from
onchocerciasis such as limbitis, iridocyclitis, sclerosing
keratitis, chorioretinitis, and papillitis. 81
Diagnosis
Physical examination and diagnosis begins with skin
biopsies. Biopsy sites in people from South America
suspected of having the onchocerciasis infection are
more commonly collected from the upper body because
the black fly endemic to the Americas is the Simulium
ochraceum, a high-biting species. This differs from
Simulium damnosum, which is endemic to Africa and a
low-biting species.82
Radiography demonstrates filamentous calcification
within nodules, particularly on soft tissue extremity
images or mammograms, although the pattern in many
cases is nonspecific. Even with the anatomic regions of
interest biopsied, the diagnosis still might be difficult
to confirm because of microcalcification occurring late
in the inflammatory process, long after the worms are
dead and fragmented.35
Ultrasonography increasingly is used in the developing
world to diagnose onchocerciasis and identify associated
skin nodules. With improvements in 2-D grayscale imaging and use of higher frequency transducers, onchocercomas can be categorized and differentiated from other
nodules and lymph nodes. A typical pattern demonstrates
a lateral acoustic (refractive) shadow, a hypoechoic rim
or layer, and a central zone of intermediate echogenicity
in which numerous tiny, highly echogenic foci are
seen. These foci are referred to as a worm center. Single
and conglomerate nodules also can be distinguished
(see Figure 10). The conglomerate can be evaluated
based on the presence of multiple worm centers.35 After
images are obtained, nodules can be removed surgically.
Comparisons then can be made between sonograms and
pathological sections (see Figure 11).
Advances are being made with the use of MR
imaging in regard to associations between onchocerciasis and epilepsy.83 T1-weighted and T2-weighted,
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Figure 10. Characteristic sonographic appearance of a solitary
onchocercal nodule. Worm center (small arrows). Lateral acoustic shadows (large arrows) and echo-poor capsule (arrowhead).
Reprinted from Palmer P, Reeder M. The Imaging of Tropical
Diseases [DVD]. The International Society of Radiology Web
site. http://www.isradiology.org/tropical_deseases/tmcr/chapter
26/clinical8.htm. Accessed December 17, 2015.
fluid-attenuated inversion recovery imaging and 3-D
spoiled gradient recall imaging sequences to examine
hippocampus anatomy have shown an association of
intraparenchymal brain pathologies and O volvulus
infection that might indicate a cause of nodding syndrome in young people in areas endemic for onchocerciasis. Symptoms of nodding syndrome are repetitive
dropping forward of the head and other seizure-like
activity.83
A diagnostic test reserved for cases in which all
other tests prove negative is the Mazzotti test. This
test involves 5 mg diethylcarbamazine administered
orally to the patient to inhibit neuromuscular transmission in nematodes. The test is considered positive for
onchocerciasis if an intense skin rash and itching results
within 2 hours; these symptoms are caused by dying
microfilariae. Corticosteroids can be administered
postexamination to relieve pruritus for a few days, but
severe systemic reactions and ocular complications are
risks with this diagnostic method.74
Treatment
The treatment of choice for onchocerciasis is ivermectin, which has been shown to reduce the occurrence
of blindness and to reduce the occurrence and severity
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B
Figure 11. A. Excision of an oncheroma under local anesthesia.
B. Open nodule showing coiled adult worms in a central soft core
with fibrotic outer layer. Reprinted from Palmer P, Reeder M. The
Imaging of Tropical Diseases [DVD]. The International Society of
Radiology Web site. http://www.isradiology.org/tropical_deseases
/tmcr/chapter26/clinical6.htm. Accessed December 17, 2015.
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and the Caribbean is S mansoni. The various strains of
schistosomes have different egg-laying capacities, which
have been estimated to be as high as 3500 eggs per day in
the case of S japonicum and 300 eggs per day in the case
of S mansoni.35 Schistosomes can survive in the water
without a host for 48 hours. People become infected
when their skin comes in contact with the contaminated
water and the cercariae penetrate the human host’s skin.
While the egg matures into an adult worm, it can travel
to and invade the intestines, liver, or bladder. Schistosoma
mansoni causes intestinal schistosomiasis, dwelling
within the blood vessels surrounding the intestines, in
contrast to other strains that can cause urogenital schistosomiasis.85 The next generation of schistosome eggs
undergoes asexual multiplication and is deposited within
the rectum or large intestine. From there, the eggs are
reintroduced to the environment via poor sanitation practices and contamination of fresh water with infected feces
(see Figure 12).35
of skin symptoms. Another preventive measure involves
using environmentally safe insecticides to spray areas
where black flies lay their eggs.79
Pan American Health Organization resolution
CD48.R12 was established in 2008 to interrupt transmission of onchocerciasis in Latin America.80 This
public health program has been effective in eliminating
the disease in Colombia and Ecuador. Such programmatic success is attributed to robust public-private
partnerships involving national governments, local
communities, donor organizations, intergovernmental
bodies, academic institutions, nonprofit organizations,
and the pharmaceutical industry. The accomplishment
of disease control in these Latin American countries is
informing the program about ways to control and eliminate onchocerciasis in Africa.80
Schistosomiasis
Epidemiology
Schistosomiasis, also known as bilharzia, 84 ranks
second only to malaria in prevalence, affecting approximately 240 million people worldwide.85 It is considered
the most lethal of all NTDs, leaving many chronically
ill and causing 100 000 deaths annually.74,84,86 More than
76 countries are affected, with Brazil, Suriname,
Venezuela, the Dominican Republic, Guadeloupe,
Martinique, and Saint Lucia experiencing the
greatest impact within South America and the
Caribbean.84 These regions have a tropical and
sub-tropical climate and consist of limited-resource
communities without potable water and adequate
sanitation.
Pathophysiology
Disease transmission occurs when infectious
forms of the parasite (cercariae) living in certain
types of freshwater snails emerge and contaminate the surrounding environment. Human hosts
become infected when they come into contact with
fresh water infested with blood trematodes, known
as schistosomes. Most human infections are caused
by the larval forms of parasitic blood fluke strains
including Schistosoma mansoni, Schistosoma haematobium, or Schistosoma japonicum84; however,
the most common variety within South America
408
Clinical Manifestations
In the first days of infection, a rash or uticaria might
develop. Fever, chills, cough, and muscle aches can
4
5
7
6
8
3
9
2
10
1
Figure 12. Life cycle of Schistosoma haematobium, Schistosoma japoni-
cum, and Schistosoma mansoni. Public domain image courtesy of the
Centers for Disease Control and Prevention.
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manifest within 1 to 2 months postinfection. The
majority of human hosts remain asymptomatic during
this early phase. Eggs dwelling within the intestine,
liver, or bladder can induce inflammation and scarring,
which are caused by the body’s reaction to the eggs produced and not by the worms themselves.84 In endemic
areas, children with schistosomiasis can manifest anemia, stunted growth, decreased physical activity, and
decreased general level of intelligence, although typically not until the condition has progressed to significant cirrhosis. 35,74,85 In children who avoid early death,
infections can become chronic.
Diagnosis
Identifying the parasite in stool and urine samples
often is the first step when schistosomiasis is among the
differential diagnoses. Evidence of infection also can be
established through blood samples. However, the accuracy of blood tests requires deferring sample collection
until 6 to 8 weeks following the most recent exposure to
contaminated water.1 The most reliable serological tests
are indirect immunofluorescence, using 2 antibodies
to label a specific target antigen with a fluorescent dye,
and ELISA. 35
Chest radiography typically displays normal lung
markings or shows increased vascular and interstitial
markings and minimal enlargement of the hilar lymph
nodes. 35 Radiography of the abdomen is of little assistance unless bladder or ureteric calcifications are present, in which cases they can be useful for investigation.
Rectal and colonic calcification might be seen, most
commonly in the right side of the colon. The radiologic
manifestation varies with bowel distention and can
therefore change frequently. Calcification might appear
laminar (formed in a lumen), amorphous (formed in a
solid organ), or corrugated (grooved) (see Figure 13).
Nonspecific hepatosplenomegaly also might be identified, with splenomegaly being particularly recognized
in patients from Brazil. Myelography can be useful to
diagnose spinal schistosomiasis but is not as accurate as
CT or MR imaging.35
Schistosoma mansoni and S japonicum infections are
investigated with barium-assisted examinations of the
bowel, as well as colonoscopy. These studies can exhibit
clusters of small, yellow, nodular pseudotubercles or
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Figure 13. Radiograph showing schistosomal calcification of the
right colon. The sigmoid colon is shortened, narrowed, and rigid.
A polyp found on sigmoidscopy at 15 cm showed schistosome eggs.
Reprinted from Palmer P, Reeder M. The Imaging of Tropical
Diseases [DVD]. The International Society of Radiology Web
site. http://www.isradiology.org/tropical_deseases/tmcr/chapter
2/mansoni3.htm. Accessed December 17, 2015.
plaques beneath the normal mucosa of the rectum. In
some cases, the bowel wall might be limited to glistening granulation tissue, whereas in others, evidence of
immune reaction might be related to polyp formation,
with polyps potentially large enough to be mistaken
for neoplasms. A biopsy of the lesions will determine
whether they contain parasitic eggs, but some patients
could have a normal examination, despite presence of
an active infection.35
Sonographic examinations can show liver enlargement, more prevalent in the left lobe than in the right.
Multiple small nodules throughout the liver parenchyma also might be identified as having a hypoechoic
character. These nodules can be 4 mm to 5 mm in
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diameter and are typically well demonstrated on CT
imaging as hypodense lesions with delayed contrast
enhancement. Diagnosis is reliable only when imaging
findings are correlated with the clinical findings, with
marked eosinophilia, and with eggs found in feces or on
biopsy.35
MR imaging previously was limited to evaluation
of the central nervous system, particularly for imaging
the brain or spinal cord when infected with S mansoni.
In addition, it was thought that MR imaging of intraabdominal schistosomiasis had little advantage over
ultrasonography or CT. 35 However, abdominal MR
imaging reveals related focal or diffuse liver disease
and vascular territories. MR can show heterogeneity of hepatic parenchyma, the presence of peripheral
perihepatic vessels, periportal fibrosis, splenomegaly,
siderotic nodules (pigmented by iron), and the presence
of venous collateral pathways. Furthermore, when compared with ultrasonography and CT, MR imaging also
might be more sensitive, showing disease progression,
stage, and response to therapy.87
Treatment
The WHO strategy on using anthelmintic drugs
makes it possible to control schistosomiasis in poor
and marginalized communities.85 Efforts to control
the disease have involved education on the appropriate
disposal of feces and urine and treatment with praziquantel.86 Although treatment with praziquantel is fairly
effective in reducing or eliminating active infection, it
is not a cure for everyone. Reinfection continues to be
a problem in high-risk communities. A repeat dose of
praziquantel, given 2 to 8 weeks after the first dose, can
improve cure rates and reduce the intensity of remaining infections in population-based programs. Repeated
dosing has demonstrated particular advantages in the
treatment of S mansoni, but less consistent improvement
was seen after double-dosing for S haematobium, the
cause of urogenital schistosomiasis.88
Soil-transmitted Helminths
Epidemiology
Soil-transmitted helminth infections are some of
the most common infections worldwide and affect
the poorest and most deprived communities. Among
410
these communities, children are most often infected.
Furthermore, because these infections are linked to
populations with poor hygiene and a lack of sanitation,
they occur wherever poverty exists. More than 4 billion
people are at high risk throughout the world, with more
than 1 billion already infected.89
Transmitted by contact with contaminated soil,
the most infectious of these parasitic worms are the
roundworm ascaris (Ascaris lumbricoides), affecting
approximately 807 million to 1.12 billion people; the
whipworm causing trichuriasis (Trichuris trichiura),
which affects approximately 604 million to 795 million
people; and hookworms (Anclostoma duodenale and
Necator americanus), affecting approximately 576 million to 740 million people.90 These diseases are distributed widely in tropical and subtropical areas where they
proliferate but also can be found in temperate zones
during warmer months.
Pathophysiology
Soil-transmitted helminths live in the human intestine,
and their eggs are passed to the environment through
the host’s feces when defecation occurs near bushes, in a
garden or field, or when used as fertilizer. After the eggs
mature in the soil, they become infectious and infect new
human hosts when the eggs are ingested, often when vegetables and fruits have not been carefully cooked, washed,
or peeled before consumption.
Ascariasis develops when larvae hatch in the small
intestine, penetrate the bloodstream, travel to the lungs,
and return to the intestines via the airway. Once Ascaris
is transmitted to a host, the adult form can live in the
body for 1 to 2 years, and grow as long as 40 cm with
the thickness of a pencil (see Figure 14).74
As with ascariasis, humans are infected with whipworm when eggs are ingested. Whipworm larvae
hatch in the small intestine, but rather than penetrating tissue and traveling throughout the host, they
mature and remain in the large intestine. The adult
whipworm grows to 4 cm and can live in a person’s
bowel for 1 to 3 years.74
Hookworm eggs are not infectious in the egg form.
They hatch while still in the soil and larvae mature
into a form that can penetrate the skin of humans.
One exception is the Anclostoma duodenale hookworm,
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vomited, or emerge through the nose or anus.
When the worms migrate to the common bile
duct, pancreatic duct, appendix, and other
7
sites, secondary conditions might develop
1
including cholangitis, cholecystitis, pyogenic
liver abscess, pancreatitis, obstructive jaun3
dice, or appendicitis. With heavy infestations
of Ascaris, masses of worms can cause intestinal obstruction, volvulus, intussusception, or
6
death.74
Heavy infections of whipworm can be
5
accompanied by abdominal cramps, tenesmus (recurrent feeling of needing to evacuate the bowels), diarrhea, distention, nausea,
and vomiting. Trichuris dysentery syndrome
might develop, particularly in malnourished
younger children, with findings resembling
inflammatory bowel disease including bloody
diarrhea and rectal prolapse. Children who
2
2
have become chronically ill might present with
iron deficiency anemia, growth retardation,
and clubbing of the fingers.74 Furthermore, a
patient with heavy infestation can lose subFigure 14. Life cycle of Ascaris lumbricoides. Public domain image courtesy of
stantial amounts of blood. For example, a
the Centers for Disease Control and Prevention.
patient with 800 worms can lose approximately 4 cc of blood per day. 35
90
which can be transmitted by ingesting its larvae.
Symptoms unique to hookworm disease include74:
Humans are at risk for hookworm infections when
■ Transient pruritic skin rash.
walking barefoot on contaminated soil. The worm
■ Pulmonary symptoms.
travels through the bloodstream to the lungs where it
■Anorexia.
spreads to the bronchi, trachea, and mouth. Once in
■Diarrhea.
the mouth, hookworms travel the alimentary canal
■ Abdominal discomfort.
and attach to the mucosa of the upper small bowel and
■ Iron deficiency.
mature into adult worms. Hookworms attached to the
Many of these symptoms result from chronic infection
mucosa begin to suck blood from the host; the amount
with large worm burdens and severe effects on the cirof blood loss is dependent on the number of adult
culatory system. Patients can experience pallor, weakworms involved in the infection.74
ness, dyspnea, and heart failure caused by anemia. In
addition, protein loss during hookworm infections can
Clinical Manifestations
lead to hypoalbuminemia, edema, and ascites. This disPeople with ascariasis typically are asymptomatic,
ease also can impair growth and cognitive development
although some patients present with fever, nonproin children.74
ductive cough, chest pain, dyspnea, eosinophilia,
and eosinophilic pneumonia when worm migration
Diagnosis
involves the lungs. During migration, adult worms
Analyzing stool samples and examining patients
can be identified as they migrate and are coughed up,
for adult worms emerging from the mouth, nose, or
4
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anus are the primary tests for ascariasis, whipworm, or
hookworm infections. Other useful tests in acute stages
include skin tests, fecal smear techniques, and medical
imaging. Serological tests, including ELISA, have been
used experimentally to measure antibodies but are not
used for routine diagnosis of ascariasis, whipworm, or
hookworm. 35
Radiologic findings of intestinal worms often are
secondary to investigation of rectal bleeding or other
colonic disease. In contrast-enhanced studies, worms
are identified as filling defects and as intestinal or biliary obstructions.74 This is true especially when imaging children with severe ascariasis. The collection of
worms contrasted against gas in the bowel (usually a
distended portion) looks like a tangled group of thick
cords and sometimes produces a “whirlpool” effect
(see Figure 15).35
Figure 15. An upper gastrointestinal series reveals multiple
ascarids in the stomach and proximal small bowel. Reprinted
from Palmer P, Reeder M. The Imaging of Tropical Diseases
[DVD]. The International Society of Radiology Web site.
http://www.isradiology.org/tropical_deseases/tmcr/chapter10
/imaging4.htm. Accessed December 17, 2015.
412
Identifying whipworm in the colon using an aircontrast barium enema examination enables visualization of wavy radiolucent outlines of numerous small
worms against the air-barium background of the colon
and rectum. Furthermore, characteristic uncurled
curvilinear patterns or S-shaped configurations of the
female worms and the tightly coiled “pinwheel” or “target” pattern of the male worm might be recognizable.
The posterior portions of the worms become outlined
and are approximately 1 cm long, with the longer, slender anterior two-thirds of the worms lying uncoated by
barium within the colonic mucosa (see Figure 16).35
In patients with chronic and severe cases of hookworm
disease, chest radiographs show a mild to moderate generalized cardiac enlargement caused by profound anemia
and hypoproteinemia. General radiography also can be
used to identify initial migration patterns of hookworms,
with radiographs of the feet and ankles demonstrating
evidence of hookworm infection (see Figure 17).35 Most
patients with hookworm infection do not demonstrate
radiographic abnormality on barium examination of the
upper gastrointestinal tract; however, small bowel abnormalities can be found in 60% of hosts, with changes being
proportional to the disease burden. For example, irregularities have been observed in the mucosal folds of the
jejunum resulting in 2 to 3 times the thickness of healthy
tissue. More advanced infections show increased tone in
several loops, narrowing of the lumen, and vigorous peristalsis appearing to be in constant motion.35
Treatment
Soil-transmitted helminths can be controlled and eliminated by drugs called benzimidazoles, which interfere
with the worm’s cellular energy metabolism. The 2 main
drugs used to treat ascariasis, whipworm, and hookworm
infections are mebendazole and albendazole. Using these
drugs is known as deworming and is not limited to treating
symptomatic infections; it also is part of large-scale prevention effort in children in endemic areas, often paired
with immunization campaigns for added effectiveness.
Dengue
Epidemiology
Dengue is the second most common vector-borne
disease in humans after malaria. A member of the genus
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A
B
Figure 16. Trichuriasis in a 7-year-
old boy with profuse rectal bleeding and innumerable whipworms
attached to the rectal mucosa.
A. Postevacuation image from
barium enema shows flocculation
of barium and poor mucosal coating. B. Air contrast study reveals
the radiolucent outlines of many
small trichurids. Reprinted from
Palmer P, Reeder M. The Imaging
of Tropical Diseases [DVD]. The
International Society of Radiology
Web site. http://www.isradiology
.org/tropical_deseases/tmcr/
chapter17/imaging.htm. Accessed
December 17, 2015.
dengue hemorrhagic fever occur each year. The disease
prevalence is attributed to climatic factors, travel, and
urbanization.74 In the past 20 years, severe epidemics
of dengue hemorrhagic fever have occurred in East
Africa, Sri Lanka, and Latin America. Despite having
this knowledge, it has been difficult to pinpoint specific
locations at greatest risk considering that the virus has
been detected in 128 countries in endemic regions.28
Chikungunya is another virus recognized as an
NTD, but it is primarily endemic to Asia and Africa.
Although it has spread to much of the Americas region
as recently as 2013, relatively speaking, it has a low
impact in Latin America.92
Figure 17. Radiograph showing a lytic lesion of the left ankle.
Subsequent histological examination confirmed that the lesion
contained calcified larvae of Necator americanus. Reprinted
from Palmer P, Reeder M. The Imaging of Tropical Diseases
[DVD]. The International Society of Radiology Web site. http://
www.isradiology.org/tropical_deseases/tmcr/chapter12/radio
logical2.htm. Accessed December 17, 2015.
Flavivirus, it is transmitted by the bite of the Aedes
aegypti mosquito, which also transmits yellow fever and
chikungunya viruses. An estimated 400 million cases
of dengue 91 and several hundred thousand cases of
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
Pathophysiology
During the rainy season in endemic regions, the breeding of Aedes mosquitoes is abundant. Poor water management in these areas often is coupled with a population
uneducated about mosquitoes’ breeding and mosquito
bite protection.93 Aedes mosquitoes spend their lifetime
near a single location, traveling an average of 400 meters.
This means that infected humans, rather than the mosquitoes, are the primary reason the virus spreads between
communities.94
The virus has 4 distinct serotypes (DEN-1, DEN-2,
DEN-3, and DEN-4), and the severity of the dengue
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burden is dependent on the number of serotypes with
which an individual becomes infected.94 The virus circulates in the blood of an infected host for 2 to 7 days
over which time the host might begin to develop symptoms. For the disease to spread among people, the mosquito must feed on a person during this period. Then
it must bite another person after an 8-day to 12-day
incubation period.
Clinical Manifestations
Dengue infection can range from being asymptomatic to causing severe hemorrhagic fever or fatal shock
(dengue shock syndrome). More than half of infected
children are asymptomatic, whereas in adults the illness
is more severe and begins more suddenly. After an incubation period of 4 to 5 days, infected individuals experience a sudden onset of “breakbone” fever including
chills, aching of the head, back, and extremities accompanied by sore throat, prostration, and malaise.94 After 3
to 4 days of infection, a maculopapular rash sparing the
palms and soles appears in more than 50% of cases.74
Dengue hemorrhagic fever typically occurs in secondary infections and in infections with DEN-2. Signs
of hemorrhage appear in the first few days of infection and include ecchymoses (nontraumatic bruises),
gastrointestinal bleeding, and epistaxis. Dengue shock
syndrome is indicated when acute fever, hemorrhagic
manifestations, pleural effusions, and ascites occur.
Other indicators of dengue shock syndrome include
continuous abdominal pain with vomiting, mucosal
bleeding, a decrease in consciousness, rash, conjunctival congestion, and hypothermia.74
Diagnosis
Serological findings can be useful in dengue
diagnosis including the nonstructural protein-1
antigen test, measurement of glycoprotein levels,
and immunoglobulin G and M tests. During the
fifth and sixth day of febrile illness from this disease,
hemagglutination inhibition antibodies begin to
appear at detectable levels.95
Medical imaging of mild dengue syndromes does
not reveal specific abnormalities. In severe cases, however, abdominal imaging might display the presence
of associated hepatomegaly, and chest radiographs can
414
show pleural effusions within the first week of infection.96 When advanced imaging is available to providers, CT scans without contrast can detect intracranial
bleeding or cerebral edema from dengue hemorrhagic
fever.
Ultrasonography can show thickening of the gallbladder wall and, in some patients, ascites. A correlation
exists between the severity of the illness and increasing
thickness of the gallbladder wall, with 93% of patients
with severe cases of dengue displaying gallbladder
wall thickness exceeding 3 mm. When there is ascites,
the gallbladder wall is significantly thicker than in
patients without intraperitoneal fluid (see Figure 18).35
Sonographic findings of fluid collection typically can
occur in the perirenal and pararenal, hepatic and splenic
subcapsular, and pericardial regions. In addition, ultrasonography can demonstrate evidence of pancreatic
enlargement and hepatosplenomegaly, with an alteration in the normal liver echo texture caused by intraparenchymal and subcapsular hemorrhages.
Although serology is used to confirm dengue fever,
ultrasonography can be used to assess the infection’s
Figure 18. A 32-year-old patient with a history of fever and thrombocy-
topenia was diagnosed with dengue. This abdominal sonogram shows
a thickened, edematous gallbladder wall. Reprinted with permission
from Santhosh VR, Patil PG, Srinath MG, Kumar A, Jain A, Archana
M. Sonography in the diagnosis and assessment of dengue fever. J Clin
Imaging Sci. 2014;4:14. doi:10.4103/2156-7514.129260.
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severity and often serves as a catalyst to disease management when serology testing is unavailable. The
severity of dengue infection is linked directly to platelet
count, with patients demonstrating all sonographic
features associated with dengue likely having platelet
counts less than 40 000/L and potentially requiring
blood transfusion. In addition, sonographic features
also have a direct relationship with the degree of thrombocytopenia affecting dengue patients.95
Treatment
No pharmaceutical treatment for dengue infections
is available. A person experiencing associated symptoms should use analgesics with acetaminophen and
avoid use of aspirin-based medications because they
can compound bleeding issues. Rest and hydration
are recommended until a physician can be consulted,
but worsening symptoms, such as vomiting and severe
abdominal pain within 24 hours of fever decline,
require emergent evaluation. In-hospital treatment
involves fluid volume support, blood products, vasopressor agents, acetaminophen, and endoscopic therapy
to assist in managing gastrointestinal hemorrhage.91
Recovery from infection by a dengue virus results
in lifelong immunity against that particular virus serotype; however this immunity provides only partial and
transient protection against subsequent infection by
the 3 other serotypes. In addition, studies show that
sequential infection increases the risk of developing a
severe dengue infection.97
Conclusion
With WHO’s official recognition of the 17 global
NTDs and the 66th World Health Assembly’s 2013
adoption of resolution WHA66.12 calling for intensified, integrated measures and planned investments to
improve the health and social well-being of populations affected by NTDs, member states are focusing
increased attention on these diseases. Although the
majority of countries endemic for NTDs within the
Americas are in Central and South America, these
conditions exist in the Caribbean and the southern portions of North America including the states bordering
the U.S. Gulf Coast. For this reason, it is important for
radiologic technologists to understand the role medical
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
imaging plays in initial disease diagnosis and confirmation, as well as recognize the radiologic manifestations
of the NTDs specific to the Americas region.
Reviewing a patient’s history for recent travel to an
endemic country can provide insight into symptoms
that initially might seem to be benign. Performing a
basic physical examination for signs of disease can trigger a need for laboratory analyses and imaging assessment. Immunosorbent assays, such as ELISA, as well as
stool sample testing often can lead directly to diagnosis
when an NTD is being considered. When such technology is unavailable, an understanding of the basic modes
of transmission for each NTD, related pathophysiology,
and common clinical manifestations can aid in selecting the appropriate imaging modality and technical
parameters necessary to make an accurate diagnosis.
In Latin America and the Caribbean, ultrasonography has been the most widely used imaging
modality given its low cost, noninvasiveness, and
portability; however, this modality can be limited by
user-dependency and considerable interobserver variability. Ultrasonography generally is used for screening
purposes to identify nonspecific evidence of parasitic
presence and invasion. In urban settings, CT and MR
technology are more likely to be available. These highresolution imaging techniques, often with the aid of
contrast enhancement, can help characterize parasitic
lesions and offer advanced assessment of organ involvement and damage.
It also is important to recognize the need for greater
investment into radiology outreach initiatives98-103
within endemic regions of the Americas to control and
reverse the spread of diseases at their points of origin.
Although an “imaging gap” continues to exist between
developed and developing countries with regard to
access to reliable imaging services and radiologyspecific training, the presence of NTDs in endemic
regions of the Americas remains a persistent risk to the
resource-rich countries that border them.
The ASRT Foundation in partnership with RAD-AID
International provides medical relief efforts to
communities around the world. Learn how you can
get involved at asrtfoundation.org/outreach.
415
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Patrick Jones, BS, R.T.(R), is a radiologic technologist in
Tulsa, Oklahoma.
Jonathan Mazal, MS, R.R.A., R.T.(R)(MR), is a radiologic technologist in Bethesda, Maryland. He is a board
member for the International Society of Radiographers &
Radiologic Technologists and also serves as the organization’s regional director for the Americas.
Reprint requests may be mailed to the American Society
of Radiologic Technologists, Communications Department,
at 15000 Central Ave SE, Albuquerque, NM 87123-3909,
or emailed to [email protected].
© 2016 American Society of Radiologic Technologists
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_trematode_infections/en/. Accessed May 31, 2015.
74. Papadakis M, McPhee SJ, Rabow MW. Current Medical
Diagnosis and Treatment 2015. 54th ed. Columbus, OH:
McGraw-Hill Education; 2015:1374-1376.
75. Toledo R, Esteban JG, Fried B. Current status of foodborne trematode infections. Eur J Clin Microbiol Infect Dis.
2012;31(8):1705-1718. doi:10.1007/s10096-011-1515-4.
76. Chai JY. Praziquantel treatment in trematode and cestode
infections: an update. Infect Chemother. 2013;45(1):32-43.
doi:10.3947/ic.2013.45.1.32.
77. Praziquantel (oral route). Mayo Clinic Web site. http://www
.mayoclinic.org/drugs-supplements/praziquantel-oral-route
/description/drg-20065610. Accessed June 1, 2015.
78. Onchocerciasis – or “river blindness” – is a parasitic disease.
World Health Organization Web site. http://www.who.int
/onchocerciasis/en/. Accessed May 1, 2015.
79. Parasites – onchocerciasis (also known as river blindness).
Centers for Disease Control and Prevention Web site.
http://www.cdc.gov/parasites/onchocerciasis/index.html.
Updated August 10, 2015. Accessed May 1, 2015.
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
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Jones, Mazal
80. Gustavsen K, Hopkins A, Sauerbrey M. Onchocerciasis in
the Americas: from arrival to (near) elimination. Parasites &
Vectors. 2011;4:205. doi:10.1186/1756-3305-4-205.
81. Banla M, Tchalim S, Karabou PK, et al. Sustainable control of onchocerciasis: ocular pathology in onchocerciasis
patients treated annually with ivermectin for 23 years: a
cohort study. PLoS One. 2014;9(6):e98411. doi:10.1371/jour
nal.pone.0098411.
82. Young RM, Burkett-Cadena ND, McGaha TW Jr, et al.
Identification of human semiochemicals attractive to
the major vectors of onchocerciasis. PLoS Negl Trop Dis.
2015;9(1):e3450. doi:10.1371/journal.pntd.0003450.
83. Winkler AS, Friedrich K, Velicheti S, et al. MRI findings
in people with epilepsy and nodding syndrome in an area
endemic for onchocerciasis: an observational study. Afr
Health Sci. 2013;13(2):529-540. doi:10.4314/ahs.v13i2.51.
84. Parasites – schistosomiasis. Centers for Disease Control and
Prevention Web site. http://www.cdc.gov/parasites/schisto
somiasis/index.html. Accessed May 18, 2015.
85. Schistosomiasis: a major health problem. The World Health
Organization Web site. http://www.who.int/schistosomiasis
/en/. Accessed April 9, 2015.
86. The burden of schistosomiasis (schisto, bilharzia, snail fever).
Centers for Disease Control and Prevention Web site.
http://www.cdc.gov/globalhealth/ntd/diseases/schisto_bur
den.html. Updatead June 6, 2011. Accessed May 18, 2015.
87. Bezerra AS, D’Ippolito G, Caldana RP, Cecin AO, Ahmed
M, Szejnfeld J. Chronic hepatosplenic schistosomiasis mansoni: magnetic resonance imaging and magnetic resonance
angiography findings. Acta Radiol. 2007;48(2):125-134.
88. King CH, Olbrych SK, Soon M, Singer ME, Carter J, Colley
DG. Utility of repeated praziquantel dosing in the treatment of schistosomiasis in high-risk communities in Africa:
a systematic review. PLoS Negl Trop Dis. 2011;5(9):e1321.
doi:10.1371/journal.pntd.0001321.
89. Intestinal worms. The World Health Organization Web site.
http://www.who.int/intestinal_worms/en/. Accessed June
15, 2015.
90. Parasites – soil-transmitted helminths. http://www.cdc.gov
/parasites/sth/. Updated January 20, 2013. Accessed June
15, 2015.
91. Dengue. Frequently asked questions. Centers for Disease
Control and Prevention Web site. http://www.cdc.gov
/dengue/fAQFacts/index.html. Updated June, 15 2015.
Accessed Janaury 8, 2016.
92. Weaver SC, Forrester NL. Chikungunya: evolutionary history and recent epidemic spread. Antiviral Res. 2015;120:3239. doi:10.1016/j.antiviral.2015.04.016.
93. Singh B. Dengue outbreak in 2006: failure of public health
system? Indian J Community Med. 2007;32(2):99.
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
94. Thongcharoen P. Monograph on Dengue/Dengue
Haemorrhagic Fever. Geneva, Switzerland: World Health
Organization; 1983:22.
95. Santhosh VR, Patil PG, Srinath MG, Kumar A, Jain A,
Archana M. Sonography in the diagnosis and assessment of dengue fever. J Clin Imaging Sci. 2014;4:14.
doi:10.4103/2156-7514.129260.
96. Wang CC, Wu CC, Liu JW, et al. Chest radiographic presentation in patients with dengue hemorrhagic fever. Am J Trop
Med Hyg. 2007;77(2):291-296.
97. Dengue control. The World Health Organization Web site.
http://www.who.int/denguecontrol/human/en/. Accessed
June 15, 2015.
98. Culp M, Mollura DJ, Mazal J; RAD-AID Conference
Writing Group. 2014 RAD-AID Conference on
International Radiology for Developing Countries: the
road ahead for global health radiology. J Am Coll Radiol.
2015;12(5):475-480.
99. Welling RD, Azene EM, Kalia V, et al. White Paper Report of
the 2010 RAD-AID Conference on International Radiology
for Developing Countries: identifying sustainable strategies for imaging services in the developing world. J Am Coll
Radiol. 2011;8(8):556-562. doi:10.1016/j.jacr.2011.01.011.
100.Everton KL, Mazal J, Mollura DJ; RAD-AID Conference
Writing Group. White Paper Report of the 2011 RAD-AID
Conference on International Radiology for Developing
Countries: integrating multidisciplinary strategies for
imaging services in the developing world. J Am Coll Radiol.
2012;9(7):488-494.
101.Mollura DJ, Mazal J, Everton KL, et al. White Paper Report
of the 2012 RAD-AID Conference on International
Radiology for Developing Countries: planning the
implementation of global radiology. J Am Coll Radiol.
2013;10(8):618-624. doi:10.1016/j.jacr.2013.01.019.
102.Mollura DJ, Shah N, Mazal J; RAD-AID Conference
Writing Group. White Paper Report of the 2013 RAD-AID
Conference: improving radiology in resource-limited regions
and developing countries. J Am Coll Radiol. 2014;11(9):913919. doi:10.1016/j.jacr.2014.03.026.
103.Mollura DJ, Azene EM, Starikovsky A, et al. White Paper
Report of the RAD-AID Conference on International
Radiology for Developing Countries: identifying challenges, opportunities, and strategies for imaging services in
the developing world. J Am Coll Radiol. 2010;7(7):495-500.
doi:10.1016/j.jacr.2010.01.018.
419
Directed Reading Quiz
16802-01
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Expires April 30, 2019*
Medical Imaging of Neglected
Tropical Diseases of the Americas
To earn continuing education credit:
 Take this Directed Reading quiz online at www.asrt.org/drquiz.
 Or, transfer your responses to the answer sheet on Page 424
410M
and
and
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*Your answer sheet for this Directed Reading must be received in the ASRT office on or before this date.
Read the preceding Directed Reading and choose the answer that is most correct based on the article.
1. Chagas disease is caused by the parasite ______
and is transmitted by triatomine bugs.
a. Giardia lamblia
b. Trypanosoma cruzi
c. Entamoeba histolytica
d. Plasmodium knowlesi
4.The predominant means of spreading cysticercosis
infections is:
a. person to person.
b. via environmental sources.
c. animal to person.
d. insect to person.
2. Medical imaging of Chagas disease can reveal:
1. cardiomyopathy.
2. calcifications in the apical vasculature.
3. delayed esophageal motility.
5. In regions where computed tomography (CT) and
magnetic resonance (MR) imaging are available,
these scans can provide information on:
1. morphology and localization of
cysticercosis cysts.
2. stage of cysts.
3. inflammation.
a.
b.
c.
d.
1 and 2
1 and 3
2 and 3
1, 2, and 3
3. Cysticercosis infections are caused by:
a.helminths.
b. filarial worms.
c.flatworms.
d.mosquitoes.
a.
b.
c.
d.
1 and 2
1 and 3
2 and 3
1, 2, and 3
continued on next page
420
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
Directed Reading Quiz
6. The majority (50%-70%) of echinococcosis cysts
develop in the liver.
a.true
b.false
7. A patient presenting with a cyst-like mass and a
history of recent exposure to sheepdogs while in an
area in which Echinococcus granulosus is endemic is
suggestive of:
a. Chagas disease.
b. cystic echinococcosis.
c.neurocysticercosis.
d.paragonimiasis.
8. All of the following are descriptions of Gharbi
classification type for echinococcosis cysts, except:
a. pure fluid collection in the cyst.
b. fluid collection with septa.
c. reflecting thick walls.
d. multiple cysts with calcified walls .
9.The most common site of a paragonimiasis infection
is the:
a.heart.
b.lung.
c.brain.
d.extremities.
10. Chest radiographs of people suspected of having a
paragonimiasis infection show abnormalities of the
lungs or pleura similar to tuberculosis including all of
the following except:
a.cavities.
b.fibrosis.
c.infiltrates.
d. “air bubble” sign.
11. Which is the most characteristic radiologic sign of
the mature stage of paragonimiasis and represents
worms attached to the wall of a cyst?
a. air bubble
b.Cumbo
c. solar eclipse
d.double-arch
12. The characteristic convoluted channels of
fascioliasis are less identifiable on ultrasonography,
and therefore, ______ is the preferred imaging
modality for the hepatic form of this disease.
a.CT
b.MR
c. positron emission tomography
d.radiography
13. Changes in skin thickness, pigmentation, edema,
and scarring of the epidermis are key indicators of:
a.dengue.
b.fascioliasis.
c.onchoceriasis.
d.schistosomiasis.
14. Which modality is being used increasingly in the
developing world to diagnose onchocerciasis?
a.ultrasonography
b.radiography
c.CT
d.MR
15. This disease is considered the most lethal of
all neglected tropical diseases leaving many
chronically ill and causing 100 000 deaths annually.
a.onchocerciasis
b.schistosomiasis
c.dengue
d.chorioretinitis
continued on next page
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
421
Directed Reading Quiz
16. Which imaging modality might be more sensitive
to show disease progression, stage, and response to
therapy for Schistosoma mansoni infections?
a.CT
b.MR
c.radiography
d.ultrasonography
17. Once ______ is transmitted to a host, the adult
form can live in the body for 1 to 2 years, and grow
as long as 40 cm with the thickness of a pencil.
a. Ascaris
b. Schistosoma mansoni
c. Simulium damnosum
d. Trypanosoma cruzi
18. Heavy infestations of ______ can involve masses
of worms that can cause intestinal obstruction,
volvulus, intussusception, or death.
a. Ascaris
b. Fasciola hepaticus
c. Onchocera volvulus
d. Schistosoma japonicum
19. Identifying whipworm in the colon using an aircontrast barium enema enables visualization of
which of the following?
1. radiolucent outlines of small worms
2. S-shaped configurations of female worms
3. tightly coiled male worms
a.
b.
c.
d.
422
1 and 2
1 and 3
2 and 3
1, 2, and 3
20. Aedes aegypti mosquitoes transmit all of the
following viruses except:
a.malaria.
b.dengue.
c.chikungunya.
d. yellow fever.
21. Ultrasonography can show which signs of dengue
fever?
1. thickening of the wall of the gallbladder
2.ascites
3. kidney stones
a.
b.
c.
d.
1 and 2
1 and 3
2 and 3
1, 2, and 3
22. Recommendations to treat dengue symptoms
include:
1. aspirin-based medications.
2.rest.
3.hydration.
a.
b.
c.
d.
!
1 and 2
1 and 3
2 and 3
1, 2, and 3
Your post-test is now complete.
The ARRT now requires only 8 questions per CE credit.
For additional information, read the recent ASRT Scanner
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RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
✁
Carefully cut or tear here.
CE
Directed Reading
The Pediatric Urinary Tract and
Medical Imaging
Steven M Penny, MA, R.T.(R), RDMS
The pediatric urinary tract
often is assessed with medical
imaging. Consequently, it is
essential for medical imaging
professionals to have a
fundamental understanding
of pediatric anatomy,
physiology, and common
pathology of the urinary tract
to provide optimal patient
care. This article provides an
overview of fetal development,
pediatric urinary anatomy
and physiology, and common
diseases and conditions of the
pediatric urinary tract.
This article is a Directed
Reading. Your access to
Directed Reading quizzes
for continuing education
credit is determined by
your membership status
and CE preference.
After completing this article, the reader should be able to:

Describe the anatomy and physiology of the urinary tract.
 Discuss typical fetal development and congenital malformations of the urinary tract.
 Describe the various solid tumors that can be discovered when imaging the pediatric
urinary tract.
 Describe the etiology and treatment of urinary tract infections and vesicoureteral reflux
disease.
 Explain the role of medical imaging in diagnosing pediatric urinary tract conditions.
R
enal diseases are a primary
cause of morbidity and mortality in children, and urinary
tract infections (UTIs) are
second only to respiratory infections
as the most common bacterial infections in young children.1 In addition,
many pediatric conditions and diseases arise during fetal development, and
urinary tract conditions in children
can require accurate medical history
and laboratory and imaging studies for
diagnosis.1 It is estimated that a child
in the United States will receive 7
diagnostic imaging examinations by
the age of 18, and the most common
type of examinations involve conventional radiography (84.7%) and computed tomography (CT, 11.9%).2
Radiologic technologists should
understand urinary tract health and
diseases so they can optimize medical
imaging and as low as reasonably
achievable (ALARA) principles. 3
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
Anatomy and Physiology
The urinary tract is divided into
upper and lower portions. The upper
urinary tract consists of the paired kidneys and ureters, and the lower urinary
tract includes the urinary bladder and
urethra (see Figure 1).
The comma-shaped kidneys are concave medially and convex laterally. Each
kidney consists of an upper or superior
pole, midportion, and lower or inferior
pole. They are retroperitoneal organs,
located toward the posterior aspect of
the body and adjacent to the spine bilaterally. The bulky liver occupies most of
the body’s right upper quadrant, leading to the right kidney’s slightly lower
position in the body compared with
the left kidney. The right kidney is bordered anteriorly and inferiorly by the
right lobe of the liver.
Atop the right kidney is the right
suprarenal gland, also referred to as the
adrenal gland. The hepatic flexure of
425
CE
Directed Reading
The Pediatric Urinary Tract and Medical Imaging
Adrenal gland
Kidney
Renal
pelvis
Calyces
Gerota
fascia
Renal
hilum
Fat
Inferior
vena cava
Abdominal
aorta
Ureter
Bladder
Urethra
Figure 1. Urinary tract anatomy.
the colon is located anterior to the right kidney. On the
other side of the body, within the left upper quadrant,
the left kidney is capped by the left adrenal gland, which
rests slightly anterosuperiorly and medial to the upper
pole of the left kidney.5 Also anterior to the left kidney
are the spleen, splenic flexure of the colon, and tail of
the pancreas.5
The kidneys are vital organs, and several surrounding soft and hard tissue structures protect them from
injury. In some individuals, the lower ribs partly guard
the kidneys, which typically are situated between the
12th thoracic and 4th lumbar vertebrae.5 The kidneys’
posterior location within the body further protects the
organs by proximity of several muscles, specifically the
psoas, transversus abdominis, and quadratus lumborum.5 The kidneys also are surrounded by several layers
of fat and a layer of connective tissue called the renal
fascia or Gerota fascia. 4 The bilateral adrenal glands also
are covered by Gerota fascia.
Each kidney comprises 2 primary parts, the renal
parenchyma and the renal sinus. The parenchyma is the
functional portion of the kidney, and the sinus houses
the collecting system. The fundamental roles of the
kidneys are to filter blood, excrete metabolic waste, and
426
dynamically reabsorb amino acids, ions, glucose, and
water. 6 The functional unit of the kidney is the nephron,
a complicated group of microscopic pipes and sieves
composed of specialized cells that help sustain homeostasis by filtering blood (see Figure 2).4 At birth, each
kidney is made up of more than 1 million nephrons. 6,7
Each nephron moves filtration products from an area
of high concentration to an area of low concentration, a
function that leads to the creation of urine.5 Nephrons
work so efficiently that by the time filtration is complete, urine comprises elements that are essentially toxic
or of no physiological use to the body, such as urea,
ammonia, bilirubin, and drug components.5,8 The kidneys filter the body’s entire blood volume approximately every 40 minutes, returning 99% of the blood volume
to systemic circulation and excreting only 1% of the volume.5 Of the 1% excreted, the evacuated urine consists
of 95% water and 5% nitrogenous waste and inorganic
salts.5 The management of blood volume, paired with
the production of the enzyme renin by the kidneys, acts
as the body’s blood pressure regulator as well. Other
hormones are produced by the posterior pituitary gland,
adrenal cortex, and the kidneys to maintain homeostasis (see Table 1).5 Their production is stimulated by
blood volume or oxygen levels.
Afferent
arteriole
Proximal nephron
tubule
Glomerulus
Distal
nephron
tubule
Bowman
capsule
Collecting
tubule
Loop of Henle
Figure 2. Nephron anatomy.
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
CE
Directed Reading
Penny
Blood pressure regulates the glomerular filtration
rate (GFR) within the nephron.8 The glomerulus, which
is surrounded by the Bowman capsule, is a group of
capillaries that forms the basic filtration unit of the kidney.9 Tubular reabsorption, a function of the nephron
in which solutes useful for the body are reabsorbed into
the bloodstream, requires 6% of the body’s total at-rest
calorie consumption.5 GFR is a helpful index to evaluate kidney function because it measures the amount
of plasma filtered across the glomerular capillaries and
then correlates the information with the kidneys’ ability
to filter fluids and other substances.10
The inner portion of the kidney, called the sinus,
accommodates the collecting system, renal vasculature, and lymphatics. Before completely exiting the
kidney, urine passes into several channels and temporary storage areas within the sinus. After it moves
from the nephron, the fluid passes through the minor
calyces. The term calyx, singular for calyces, has a
Greek origin that means “seed pod, husk, or outer
covering.” 4 The minor calyces give rise to the major
calyces and then the renal pelvis. The minor calyces
and renal pelvis are located within the renal hilum.
The hilum also is the location of the chief renal vein
and the renal artery.
Gravity pulls the urine into the bilateral ureters,
which are tubular structures 2 mm to 8 mm in diameter and measuring between 8 inches and 10 inches
(20.3 cm and 25.4 cm) in length in adults.5 The ureter
and renal pelvis join at the ureteropelvic junction. Urine
moves into the bladder through gravity and peristalsis, a
series of involuntary contractions. 4 The ureter narrows
Hormone
Produced by
Effect
slightly in 3 areas, which can be susceptible to obstruction. These areas include the11:
¡ Ureteropelvic junction.
¡ Ureters’ entrance to the bladder.
¡ Point at which the ureters cross the iliac blood
vessels.
The ureter meets the bladder at the ureterovesical
junction. At this intersection, the ureterovesical valves,
which help regulate urine flow, control the release of
urine into the bladder and prevent retrograde flow of
urine from the bladder to the ureter.
Positioned in the pelvis posterior to the pubic
bone, the urinary bladder is a hollow, muscular organ
that provides temporary storage for more than 2 cups
of urine in adults. The bladder’s muscular wall acts
much like a balloon; when the organ is empty, the wall
is thick, and as the bladder fills with urine, the wall
becomes distended and thinner. Bladder emptying is
controlled by the somatic, or voluntary, nervous system
in concert with both the sympathetic and parasympathetic parts of the visceral nervous system.12
The paired ureters, which ordinarily connect inferior
and posterior to the bladder, help to form an area at the
level of the bladder neck referred to as the trigone. The
third component of the trigone is the urethra, through
which urine exits. The internal urethral sphincter
relaxes and allows urine to exit the bladder and enter
the urethra. The urethra is a cylindrical structure that
varies in length according to sex and the individual. The
male urethra, which passes through the center of the
prostate, can be 16 cm longer than the female urethra. 5
Because the male urethra is so much longer, men are
less likely to complain of lower UTIs than are women.
At the distal end of the urethra, the external urethral
sphincter facilitates the final evacuation of urine from
the body.5
Antidiuretic
hormone
Posterior
pituitary gland
Increases water
reabsorption
Embryology and Fetal Development
Aldosterone
Adrenal cortex
Increases salt and water
reabsorption
Renin
Kidney
Increases systemic blood
pressure
Erythropoietin
Kidney
Increases red blood cell
production
Table 1
Hormones That Influence Renal Function5
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
The genitals and the urinary tract develop at the
same time in the fetus; these 2 systems often are
grouped and referred to as the genitourinary or urogenital system. The embryonic period, which lasts from
the point of fertilization through the eighth week of
gestation, is a crucial and dynamic period of human
development. By the eighth week, most organ systems,
427
CE
Directed Reading
The Pediatric Urinary Tract and Medical Imaging
Fourth Week
Pronephros
Mesonephros and
mesonephric tubules
Undifferentiated
mesonephric tissue
Cloaca
Ureteric bud
Sixth Week
Metanephric
blastema
Ureteric bud
Eighth Week
Undifferentiated
gonad
Degenerating
mesonephros
Differentiating
metanephric tissue
Urachus
Rectum
Müllerian duct
Urogenital sinus
Figure 3. Gestational development of the urinary system.
428
including the urinary system, are in place and somewhat functional (see Figure 3). 6
The urogenital system develops in 3 stages: pronephros, mesonephros, and metanephros. A group of
cells referred to as the urogenital ridge lies adjacent to
the primitive aorta of the embryo and has 2 parts: the
nephrogenic cord and the gonadal ridge. 6 The cells that
make up this ridge develop the pronephros, which is the
primordial nonfunctional kidney, along with the mesonephros and metanephros.
The first functional kidney unit, the mesonephros, is
present as early as the fourth week of gestation. 6 By the
end of the fifth week, the metanephros is in place, and
the structure eventually evolves into the fully formed
adult kidney. 5 However, the metanephros is not fully
functional until the end of 8 weeks of gestation, and
begins producing urine between 11 and 13 weeks.5,6,13 As
they develop, the metanephric kidneys lie deep in the
pelvis of the embryo, but as the embryonic abdomen
grows, the kidneys ascend to their correct position by
12 weeks gestation.13 Each kidney initially begins as a
separate body of tissue referred to as a renunculus, but
the renunculi progressively fuse over the course of gestation.14 The paired ureters form from the metanephric
ducts around the same time as the kidneys. 6
Draining of the embryonic kidneys is performed by
the mesonephric ducts, also referred to as the Wolffian
ducts.5 Lateral to the mesonephric ducts are the paramesonephric or Müllerian ducts. At this point in gestation,
the sex of the fetus plays a vital role in the appropriate development of the urogenital tract. In the male
fetus, the mesonephric ducts eventually form most of
the male genital tract, and the paramesonephric ducts
degenerate. In the female fetus, the paramesonephric
ducts form most of the female genital tract, and the
mesonephric ducts degenerate. In either situation, remnants of the degenerated ducts can persist. 6
Early in development, the embryo has a solitary
opening shared by the urinary and alimentary tracts, a
structure referred to as the cloaca. The ventral portion
of the cloaca is the urogenital sinus. The urinary bladder, which is formed by the allantois, the fetal yolk sac,
and the upper part of the urogenital sinus, develop early
in the fourth week of gestation. 6 The lower parts of the
urogenital sinus develop into the urethra. 6
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
CE
Directed Reading
Penny
Visit asrt.org/as.rt?XQmWMF to see a urogenital
development animation from Duke University Medical
School.
In childhood and adulthood, the kidneys are
dynamic organs that help sustain life. For the fetus,
kidney development and function is even more crucial.
From the end of the first trimester, the fetal kidneys
continually produce urine. Urine is primarily an excretory by-product of renal function in postnatal life, but
the formation and excretion of urine is vital for the
developing fetus. For example, most amniotic fluid is
made up of fetal urine, and the fluid is essential for the
developing fetus. Amniotic fluid helps protect the fetus
from trauma, permits symmetric and regular growth
of the musculoskeletal system, and is important for
gastrointestinal and pulmonary system expansion.14
Specifically, ingestion of amniotic fluid is essential for
human growth and development.15 Swallowing allows
the fetus to absorb the fluid, which is filtered in the fetal
kidneys.
The process of fetal swallowing and voiding
provides a balance that is necessary for appropriate
fetal growth. About midway through the pregnancy,
the fetus swallows amniotic fluid at a rate of 4 mL
to 11 mL and excretes 7 mL to 14 mL of urine in
24 hours.15 Consequently, the assessment of kidney
function in utero is based partly on amniotic fluid
volume. Oligohydramnios, a state of amniotic fluid
volume lower than expected for gestation period, can
occur because of congenital anomalies of the fetal
urinary system.
Congenital Anomalies
Congenital anomalies of the urinary system have
been observed in up to 10% of the population.1 Use of
medical imaging can help clinicians discover a congenital anomaly of the urinary tract at birth or even before
birth. Anomalies typically begin as maldevelopment
of the fetal kidneys in number, position, or fusion.14
Urinary system anomalies constitute 25% of all malformations diagnosed in utero with sonography. This
makes the urinary tract the third most common system
subject to congenital anomalies; most diagnosed anomalies occur in the central nervous system, followed by
the cardiovascular system.1,16
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
Several forms of renal cystic disease, some of which
are inherited, can be diagnosed in a fetus or with postnatal imaging (see Table 2). Inherited renal cystic
disease can be autosomal dominant or autosomal recessive. Autosomal dominant disorders can occur in a child
when one parent has the genetic alteration, regardless of
whether the other parent carries it. An autosomal recessive disorder occurs in offspring only if both parents
carry the genetic alteration.22 A relationship between
some forms of renal cystic disease and anomalies of
other body systems is referred to as the VACTERL
association, for vertebral, anal atresia, cardiac anomalies, tracheoesophageal fistula or esophageal atresia,
renal anomalies, and limb anomalies. The VACTERL
association demonstrates the link between the associated abnormal development found in these systems.22
Examples of anomalies that might be present with renal
cystic disease include cardiac ventricular septal defects,
hemivertebra, and radial hypoplasia.22
Congenital malformations should not be confused
with inherited renal cystic disorders and anatomic
anomalies, the latter of which typically are of little
clinical significance (see Box 1). Some congenital
malformations of the urinary tract are fatal in nearly
all cases.
Renal Agenesis
The most severe form of kidney maldevelopment is
failure to form both kidneys, a disorder referred to as
bilateral renal agenesis. Bilateral renal agenesis occurs
in 0.02% to 0.04% of live births.14 Because the kidneys
create most of the amniotic fluid, the absence of fetal
kidneys dramatically affects amniotic fluid production,
causing the fetus to experience complications such as
underdevelopment of the lungs and neonatal renal failure, both of which are impairments that lead to fetal or
neonatal death.14
Fetuses affected by bilateral renal agenesis have
abnormal facial features secondary to compression
within the nondistended amniotic sac, a condition
known as Potter syndrome.23 In 2013, a newborn who
initially received a diagnosis of renal agenesis survived
birth. Once the fetal diagnosis was established using
sonography, physicians began to inject fluids around
the fetus. The fluids simulated amniotic fluid so that
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Table 2
Renal Cystic Disease17-21
Disease
Incidence
Cause
Appearance
Result
Multicystic
dysplastic kidney
1:2200-1:4300
Likely an obstruction to
the urinary tract during
fetal development
Multiple cysts of various sizes in
the renal fossa
Affected kidney is nonfunctional
and will most likely involute;
bilateral disease is fatal
Autosomal
dominant
polycystic kidney
1:400-1:1000
Hereditary abnormality
Bilateral renal enlargement with
multiple bilateral renal cysts;
cysts might be found in other
organs including liver and spleen
End-stage renal disease and
dialysis by age 50-60
Autosomal
recessive polycystic
kidney
1:20 000
Hereditary abnormality
Bilateral enlarged kidneys
Death from portal hypertension
or renal failure
Box 1
Anatomic Variants of the Kidney5,14
Fetal lobulation:
Normal renal lobulation is observed during fetal life. However,
these undulations in the renal parenchyma can persist in postnatal life, leading to a lobulated appearance of the kidney.
Hypertrophic column
of Bertin:
A prominent layer of cortex is seen between the renal
pyramids and can mimic a renal mass.
Junctional
parenchymal defect:
The defect results from the incomplete embryonic fusion of
the renunculi and is noted as a triangular band of bright tissue,
most likely in the upper pole of the kidney.
Dromedary hump:
A bulge arises or forms in the lateral margin of the middle
portion of the left kidney that can mimic a mass.
Extrarenal pelvis:
A renal pelvis develops outside of the renal hilum instead of
within it. It also can mimic a renal mass or cyst.
the fetus could survive until birth. The newborn
became a candidate for renal transplantation immediately upon birth.24
Unilateral renal agenesis, in which the fetus develops
only one kidney, typically is not fatal (see Figure 4).
Unilateral renal agenesis likely is caused by the arrested
development of the Wolffian duct.23 In this situation, if
the solitary kidney is healthy, it eventually will enlarge
and compensate for the absent kidney, producing
amniotic fluid within a typical range and allowing fetal
growth and development to progress.15 Postnatal complications can occur, however, because other urological
anomalies often accompany unilateral renal agenesis,
430
increasing the likelihood of renal
failure.25
One retrospective study found
that of 51 patients with unilateral
renal agenesis, 24% had other urological anomalies including ureterovesical junction obstruction,
vesicoureteral reflux, and bladder
dysfunction.25 Unilateral renal
agenesis also has been associated
with anomalies of the heart, vertebral column, long bones, hands,
genitalia, and anus.23
Congenital Hydronephrosis
Congenital hydronephrosis
is the dilatation of the renal collecting system at birth and accumulation of fluid
(see Figure 5). Hydronephrosis has been described as
pelviectasis, caliectasis, and pelvocaliectasis, depending
on the location of the obstruction or residual fluid.
Pelviectasis, or pyelectasis, refers to the dilatation of
the renal pelvis, and caliectasis refers to the dilatation
of the renal calyces. Pelvocaliectasis is the dilatation
of both the renal pelvis and calyces. Pelviectasis is one
of the most common fetal kidney abnormalities, with
an incidence rate of up to 5%.21 The condition leads
to repeat obstetric sonograms and often to postnatal
follow-up imaging in newborns. 21 Because pelviectasis
is a common fetal abnormality found on sonography,
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evidence of a UTI.14 A ureteropelvic junction obstruction is noted on imaging by dilatation of the renal pelvis.
More substantial obstruction can result in pelvocaliectasis and possible renal rupture with resultant dysplasia.
Ureteropelvic obstruction most often affects the left kidney.11 Treatment of congenital hydronephrosis includes
pyeloplasty or endourological repair.14
Adrenal
gland
Figure 4. Unilateral renal agenesis.
it can be an indicator for other chromosomal anomalies.26
The most common cause of congenital hydronephrosis is a ureteropelvic junction obstruction.14 The disorder
likely is caused by abnormal smooth muscle development in the area of the ureteropelvic junction, although
other causes, such as adhesions and bands, have been
suspected.14 Most congenital hydronephrosis is diagnosed prenatally, but occasionally a pediatric patient has
a palpable abdominal mass, flank pain, hematuria, or
Healthy kidney
Mild
Other Congenital Anomalies
Other congenital anomalies of the kidneys include
renal ectopia, horseshoe kidney, renal hypoplasia,
supernumerary kidney, and duplication anomalies.
An ectopic kidney, or renal ectopia, typically results
from the arrested ascension of the kidney as it moves
from the pelvis to the renal fossa. The failure of the
developing kidney to ascend to its final location in the
upper quadrant sometimes is referred to as a pelvic
kidney. Ectopic kidneys also have been discovered in
the thorax, however.14 Ectopic kidneys located in the
pelvis typically lead to increased incidence of vesicoureteral reflux, infection, obstruction, and stone
formation.9 In crossed ectopia, both kidneys are on the
same side of the body. In nearly 90% of cases, these
kidneys also are fused; this condition is called crossed
fused ectopia.14
Renal fusion, also known as horseshoe kidney, occurs
in nearly 1 of every 400 live births.9 In this condition,
the lower poles of the kidneys are fused, resulting in
a bridge of renal tissue, or an isthmus, that traverses
the midline of the body connecting the 2 kidneys (see
Figure 6). The horseshoe kidney has been associated
with an increased risk of stone formation, hydronephrosis, and infection, as well as aberrations of other
Moderate
Severe
Fluid
Ureteropelvic
junction obstruction
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
Figure 5. Congenital
hydronephrosis.
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systems, such as the cardiovascular, skeletal, and gastrointestinal systems, in one-third of affected individuals.9,14 Horseshoe kidney also increases the risk for the
development of childhood renal cancers.14 A rare type
of horseshoe kidney, in which both the upper and lower
poles are fused, is called the pancake kidney.
Renal hypoplasia is underdevelopment of the kidney,
resulting in a kidney at birth that is smaller than expected and has functional constraints (see Figure 7).23
Renal hypoplasia has been linked with fetal alcohol
syndrome and intrauterine cocaine exposure. However,
renal hypoplasia also can occur as the result of complicated vesicoureteral reflux disease in children.23 Renal
hypoplasia should be distinguished from the rare circumstance of a supernumerary kidney, in which a third,
or even fourth, underdeveloped kidney is present.23
Duplication of the renal collecting system is the most
common congenital anomaly of the urinary tract, with
an incidence of 0.8% to 5%.14 Duplication can be partial
or complete, but partial duplication is more common,
accounting for more than 95% of duplication anomalies.14 Partial duplication also is referred to as incomplete
duplication. In this situation, there are 2 separate renal
collecting systems and 2 ureters situated one on top
Figure 6. A horseshoe kidney typically is connected in the midline
by a band of renal tissue referred to as an isthmus.
432
of the other, separated by a band of renal parenchyma.
The 2 ureters exiting the systems unite somewhere
along their route toward the bladder before entering
the trigone. Thus, partial duplication results in a bifid
ureter, or fissus, that drains classically, producing no
clinical complaints.27
Complete duplication of the collecting system also
can be referred to as a duplex kidney, and it typically consists of separate upper and lower pole collecting systems
(see Figure 8). Often, these poles are referred to as the
upper moiety and lower moiety.4 A duplex kidney typically
is unilateral and found most often in women.16
The Weigert-Meyer law is used to predict the draining
patterns of the coexisting ureters in complete duplication.28 The law states that the ureter that drains the upper
moiety commonly is prone to obstruction, whereas the
lower moiety is prone to reflux. The upper moiety is
prone to obstruction because of the irregular insertion
of the ureter into the bladder, a condition known as an
ectopic ureter. This obstructed ureter frequently results in
a ureterocele, a dilatation of the ureter into the bladder.28
Furthermore, with complete duplication, the ureter that
drains the lower moiety inserts into the trigone, although
it is located lateral and superior to the upper ectopic ureter
and runs more perpendicular at the insertion point rather
than at the typical oblique angle. This type of insertion
predisposes the ureter to reflux.14,16,28
Congenital variants of the ureters, bladder, and urethra also occur. The congenital megaureter is a ureter
Figure 7. Renal hypoplasia.
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A
B
in childhood.30 Vesicoureteral reflux also is discovered
in 72% of boys with posterior urethral valves.30 These
valves typically are surgically corrected when discovered and can be treated with vesicotomy or valve
ablation, but long-term renal impairment remains a
persistent concern for most patients and routine clinical
assessment is warranted. 31
Solid Tumors
Figure 8. Partial (A) and complete (B) duplication of the ureters.
that is dilatated, possibly as the result of obstruction
or because of a neurological deformity in the smooth
muscle of the ureter.11,14 A congenital bladder diverticulum is a bulging of the urinary bladder. Congenital
diverticuli do not always lead to clinical complications.
A large diverticulum can cause urinary stasis to occur,
predisposing a child to UTIs.11
Although bladder duplication is rare, approximately
50 cases have been reported in the literature.29 One
case described a newborn who had been born with 2
external penises, a bifid scrotum containing only one
testicle, and no anal orifice.29 This child also had unilateral renal agenesis, spina bifida, scoliosis, and dislocation of the pubic symphysis, as seen in VACTERL
association between anomalies of the urinary system
and other body systems.29
The urinary bladder also can develop on the outside
of the pelvis, a condition referred to as bladder extrophy.
Surgical repair of this abnormality is possible and can
be successful, although the affected child faces future
complications including infection and an increased risk
for urinary tract carcinoma.11
With an incidence of 1:5000 to 1:8000 live male
births, posterior urethral valves are the most common cause of bladder outlet obstruction in newborn
and infant boys.30 Posterior urethral valves are not
actual valves, but rather redundant tissue folds found
within the posterior male urethra that disrupt urine
flow through the urethra, resulting in a bladder outlet
obstruction.31 Complications include bladder dysfunction, chronic renal failure, and end-stage renal disease
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
Several solid tumors in the pediatric urinary tract
can be discovered by imaging. These include angiomyolipoma, Wilms tumor, and neuroblastoma. Although
angiomyolipomas are benign, both Wilms tumors and
neuroblastomas are malignant lesions.
Angiomyolipoma
An angiomyolipoma also is referred to as a renal
hamartoma. It is a benign renal tumor that comprises
blood vessels, muscle, and fat. An angiomyolipoma is
rarely a solitary lesion in the pediatric patient.14 When
multiple angiomyolipomas are identified in infants and
children, they most often are associated with tuberous
sclerosis.14 In fact, 80% of patients with tuberous sclerosis have bilateral angiomyolipomas.19
Tuberous sclerosis is an autosomal dominant disease
characterized by the manifestation of benign tumors in
multiple organs including the brain, skin, and kidneys.32
Tumors found in the brain can result in seizures.32 On CT
scans, an angiomyolipoma appears as a hypodense lesion,
and on ultrasonography, the lesion appears hyperechoic
(see Figure 9).19 On T1-weighted magnetic resonance
(MR) scans, an angiomyolipoma appears hyperintense.19
Typically, no clinical treatment is necessary for these
small renal tumors, but angiomyolipomas larger than
4 cm might require embolization to reduce the likelihood
of complications such as rupture and hemorrhage.32
Wilms Tumor
A nephroblastoma, or Wilms tumor, is the most
common renal malignancy in children.14 It accounts
for nearly 90% of all pediatric renal malignancies, and
constitutes 8% to 10% of all neoplasms in children.33
Wilms tumor most often is discovered before a child
is 5 years old.14 Patients typically have a large, palpable mass averaging 12 cm at the time of diagnosis,
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Figure 10. Computed tomography image of a nephroblastoma
(Wilms tumor). Image courtesy of the author.
Figure 9. Sonogram of an angiomyolipoma on the right kidney
(between calipers). Image courtesy of the author.
hematuria, hypertension, and possibly fever.14,19 Because
of the fever, these patients often present to the imaging department for urinary tract ultrasonography, or a
voiding cystourethrogram (VCUG) to be evaluated for
possible vesicoureteral reflux. A Wilms tumor often is
discovered as a result of imaging for suspected vesicoureteral reflux.
Several syndromes predispose a patient to Wilms
tumor. Among them is Beckwith-Wiedemann syndrome, a multiorgan pediatric disorder that includes
findings such as gigantism, macroglossia (enlarged
tongue), and omphalocele. 34 These children also are
predisposed to malignant hepatic tumors. 34 Routine
screening of high-risk pediatric patients, especially
with ultrasonography and CT (see Figure 10), often
is warranted to identify tumors early; however,
sonography is the modality of choice for screening.14,19
There is a 95% 2-year survival rate for children who
have masses confined to the kidney, although distant metastasis produces a much poorer prognosis.19
The imaging features of the mass are unique. On a
sonogram, the mass appears large and echogenic with
distinct borders demarcated well with color Doppler
(see Figure 11).14 MR images of Wilms tumors reveal
low signal intensity on T1-weighted images and high
434
signal intensity on T2-weighted images.19 Treatment
for Wilms tumor might include surgical resection and
chemotherapy.
Neuroblastoma
A neuroblastoma is the most common abdominal
malignancy in newborns. 35 A common abdominal location for a neuroblastoma is the pediatric adrenal glands.
As with a nephroblastoma, a neuroblastoma might
be discovered incidentally during investigation of the
urinary tract for other disorders such as vesicoureteral
reflux. Patients might present with a palpable mass or
pain, but some masses secrete hormones that contribute
to varying clinical manifestations.36
Metastasis is seen in approximately 65% of cases
at initial diagnosis; the most common locations for
metastasis are the bone, lymph nodes, and possibly the
liver or lungs.19 Sonographically, a neuroblastoma typically appears hyperechoic, and on CT shows evidence
of calcification in approximately 85% of cases with
attenuation similar to or less than that of muscle.36 MR
images demonstrate low T1-weighted signal intensity
with markedly elevated T2-weighted signal intensity.36
The primary treatment for neuroblastoma is surgical
excision and chemotherapy, although in as many as 10%
of children, the tumor can regress spontaneously with
minimal therapeutic intervention. 35
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Figure 11. Sonogram of a large nephroblastoma (Wilms tumor)
noted in the left upper quadrant of this pediatric patient. Image courtesy of the author.
Urinary Tract Infections and
Vesicoureteral Reflux
Urinary tract infections are common in children, particularly when a child has an underlying anomaly such as
vesicoureteral reflux or a voiding problem. Typical renal
function is vital for homeostasis and overall quality of
life. Consequently, the assessment of renal function must
be quantifiable and accurate because early recognition
and treatment of obstruction or infection can prevent
long-term sequelae. Renal imaging can be necessary to
the diagnosis for children with chronic infections and
underlying conditions that cause serious complications.37
Laboratory tests for pediatric patients primarily are
concerned with the discovery of significant bacteriuria
or evidence of white blood cells in the urine, definitive signs of a UTI.38 A urinalysis can provide a global
assessment of overall renal function if other renal diseases are suspected.39
Obtaining a sterile urine sample in infants younger
than 24 months typically requires catheterizing the infant
or performing bladder puncture.39 Catheterization results
in a false-positive rate of less than 2% and appears to be
the most effective means to obtain a urine sample in
children who are not toilet trained.38 Conversely, bladder
puncture, also referred to as suprapubic aspiration, avoids
perineal contamination and is highly accurate, although
surgical competence is required and imaging assistance
typically is warranted.38 The clean-catch method is
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
recommended for older children who are toilet trained.37
In the clean-catch collection method, steps are taken to
sterilize the hands, skin folds, and any other possible contaminants to ensure a clean urine specimen. The patient
also places the specimen collection cup into a well-established urine stream.40
Urine samples can be tested quickly and effectively
in the outpatient setting with a dipstick. The dipstick
urinalysis provides evidence of leukocyte esterase or
nitrite, which indicate infection. 37 Microscopic evaluation of urine cultures also can be performed. The
culture is evaluated for bacteria and white blood cells in
the sample, both of which are signs of infection.37
UTIs are common in the United States, accounting for
8 million office visits and 1.5 million hospitalizations.41
The urinary tract is considered a sterile environment, and
regular voiding defends against invading and accumulating microorganisms.42 Children who have kidney malformations, such as a duplex collecting system, can have
abnormal urine flow, retained urine after voiding, reflux,
or a combination of problems.41 Nearly 8% of girls and 2%
of boys have a UTI before the age of 8 years.43 The risk
of recurrent UTI in children in the first 6 to 12 months
following an initial UTI has been estimated to be as high
as 30%.37 The overwhelming majority of these infections
in girls are the result of bacteria from the perineum that
migrate into the bladder via the urethra.44 The risk is 10
times higher for UTI in boys who have not been circumcised compared with boys who have and is secondary to
the entrapment of bacteria in the foreskin.41
Although other bacteria can cause UTIs in the
pediatric patient, Escherichia coli is implicated in nearly
80% of cases.38 Other infectious organisms known to
cause UTIs include Streptococcus, Enterococcus, and
Klebsiella.37 Most UTIs are considered ascending,
meaning that the infection begins in the lower urinary
tract with a propensity to move to the upper urinary
tract if not treated. Therefore, the bacteria irritate
the urethra initially, resulting in urethritis. From the
urethra, the bacteria can move into the urinary bladder, subsequently inflaming the bladder and resulting
in cystitis. Pediatric patients with cystitis complain of
decreased bladder capacity and an urgency to void.44 If
recommended treatment is ignored or ineffective, the
infection can move from the bladder to the ureters or
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Table 3
lymphatic channels and then to the kidneys. Once in
the kidneys, the infection can cause acute or chronic
International Reflux Study in Children Grading System44,51
pyelonephritis. 45
Spontaneous
In the early 20th century, before the advent of
Resolution
effective antibiotic treatment for febrile pediatric
Grade
Image
Description
Rate (%)
Grade I
Grade II
UTIs, the risk for death in children from acute pyelo- Normal
Grade I
Reflux into a
92-100
nephritis was approximately 20%. 43 The primary
nondilatated
complication of a febrile pediatric UTI is renal scardistal ureter
ring, occurring in 15% to 30% of children younger
than 4 years. The presence of fever increases the
Normal
Grade I
Grade II
probability of kidney involvement and the risk for
43
renal scarring.
Up to 10% of children have scarring in one or
Normal
Grade I
Grade II
both kidneys following their first symptomatic
Grade
II
Reflux into
63-76
UTI. 46 One study using intravenous pyelography
the upper
concluded that scarring in boys is caused mostly Grade III
collecting
Grade IV
Grade V
by congenital dyplasia; in two-thirds of girls with
system
scarring, the cause was considered to be a UTI. 47 Normal
without
Grade I
Grade II
Scarring of the renal parenchyma can lead to adult
dilatation
hypertension (23%), end-stage renal disease (10%),
and toxemia during pregnancy (13%). 48 Therefore,
Grade III
Grade IV
Grade V
treatment for children with a UTI typically is
Grade III
Reflux into
53-62
an aggressive medical or surgical approach that
a dilatated
includes an investigation of possible
of
ureter or
Gradesources
III
Grade IV
Grade V
infection such as ruling out vesicoureteral reflux. 43
blunting
Vesicoureteral reflux is diagnosed
with
relative
of calyceal
Normal
Grade I
Grade II
frequency and is the most common heritable disease
fornices
of the genitourinary system. 49 The retrograde flow
Grade IV
Grade V
of urine disrupts the typical flow but does so in the Grade III
14,50
usually sterile environment of the urinary tract.
Grade IV
Reflux into
32-33
However, reflux can cause infectious bacteria in
a grossly
urine to ascend from the bladder to the kidney.
dilatated
ureter and
Vesicoureteral reflux can be graded based on the
calyces
International Reflux Study in Children grading system (see Table 3).44 Two common procedures used to
assess vesicoureteral reflux are the voiding cystoureGrade
III
Grade IV
Grade V
throgram VCUG and radionuclide
cystogram.
Grade V
Massive reflux No data
Children with known vesicoureteral reflux and
with urethral
a history of UTIs have long had their conditions
dilatation and
managed with prophylactic antibiotic medications
tortuosity and
to prevent UTIs. However, some concern has been
effacement of
raised over the risk of adverse effects from this
the calyceal
treatment and the increased risk for antibiotic resisdetails
tance that can result from the medications’ overuse. 46 In addition, vesicoureteral reflux can resolve
436
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spontaneously by age 10. Most children outgrow
reflux, depending on the severity of the disorder.19
Spontaneous resolution is thought to be the result of
the normal ureteral growth in length that decreases
the likelihood of reflux and occurs in as many as 80%
of children with this condition. 50
Physicians and researchers have sought the optimal
method for treating patients with suspected vesicoureteral reflux resulting in UTIs. Some clinicians believe
that vesicoureteral reflux might not play the fundamental
role in the pathophysiology of renal damage that was
once believed.52 One author suggests instead of imaging
for evidence of vesicoureteral reflux, the trend is to more
aggressively manage UTIs.52 Accordingly, the American
Academy of Pediatrics recently sought to answer several
questions regarding testing and management of UTIs in
young children (see Box 2).53
According to the 2011 recommendations of the
American Academy of Pediatrics, the diagnosis of
UTI in a child between 2 months and 2 years of age
is based on the presence of both pyuria and at least
50 000 colonies per mL of a single uropathogenic
organism. 54 Clinical practice guidelines suggest that
once the diagnosis is made, the child should undergo
appropriate antibiotic treatment for 7 to 14 days with
close clinical follow-up. 54 The guidelines also suggest
ultrasonography of the urinary tract to detect potential anatomic abnormalities such as hydronephrosis.
Although a VCUG is not recommended after the first
UTI, if a sonogram indicates hydronephrosis or other
findings suggestive of obstruction or vesicoureteral
reflux, a VCUG is recommended. 54 A VCUG also is
recommended for recurrent febrile UTIs. 54
Although antibiotic prophylaxis remains a core
management strategy for UTIs associated with vesicoureteral reflux, surgical intervention is favored for
children with higher grades of reflux or apparent renal
scarring. 43 Vesicoureteral reflux also can be treated with
surgical intervention in which the ureter is reimplanted
and repositioned or a synthetic bulking agent is injected
endoscopically.43
The endoscopic management of vesicoureteral reflux
with injection of synthetic or natural materials into
the vesicoureteric orifices was introduced into clinical practice more than 25 years ago.55 This procedure
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
Box 2
American Academy of Pediatrics 2011 Guidelines
on Urinary Tract Infections53,54
In 2011, a committee revising the American Academy of
Pediatrics clinical guidelines on diagnosis and management
of urinary tract infections (UTIs) in infants and children aged
2 months to 24 months considered the following questions:
1. Which children should have their urine tested?
2. How should the urine sample be obtained?
3. How should UTIs be treated?
4. What imaging and follow-up are recommended after the
diagnosis of a UTI?
5. How should children be followed after a UTI has been
diagnosed?
is called a subureteral Teflon injection, or STING.56
Materials used in the procedure now include Teflon,
silicone, and bovine collagen. 55 Dextranomer/hyaluronic acid copolymer (Deflux, Salix Pharmaceutical
Inc) is the most recent synthetic material used. The
material has been considered successful in most cases,
although complications have been reported and include
transient infections, transient obstruction, the formation of granulomas, and pseudocysts around the injection site.55 Success rates for STING procedures have
been described as lower than those for open surgery.56
Ultrasonography and fluoroscopy can be used postsurgically to assess the material’s proficiency at preventing
reflux and the durability of the synthetic materials used.
Role of Medical Imaging
Pediatric patients present unique challenges, including distinctive pediatric pathologies, for health care
practitioners. Imaging has become critical for the
detection and diagnosis of congenital anomalies and
the development of a treatment plan for many pediatric
urinary tract conditions.2
Radiography and Fluoroscopy
Conventional abdominal radiography can help physicians with general assessment of some urinary tract
pathologies, especially those such as renal tumors that
distort healthy anatomy. The VCUG, also referred to
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as a micturating cystourethrogram, is the most frequently
performed pediatric fluoroscopic examination in the
radiology department for investigating lower urinary
tract disease.57 The VCUG allows the physician to
see the configuration of a child’s urinary bladder and
urethra while simultaneously looking for evidence of
functional and congenital abnormalities that underlie
symptoms (see Figures 12-13).47
A child must be catheterized for a VCUG. A 5F to 8F
Foley catheter is placed through the urethra to administer
iodinated contrast media to the bladder.58 Once the bladder is filled, images are obtained of the distended bladder,
and then the patient must void on command under direct
fluoroscopic imaging while the physician evaluates for
evidence of vesicoureteral reflux, dysfunction, congenital
anomaly, or other diseases or disorders.57 VCUG helps
identify the presence of reflux in association with ureteropelvic junction obstruction, ureteroceles, and posterior
urethral valves, as well as delineating both bladder and
other urethral anomalies.59 For the best examination
results, the pediatric patient must be cooperative and the
fluoroscopic instruments optimized for obtaining rapid
images.57 Personnel involved in the procedure, including
the radiographer or radiologist assistant, radiologist, and
parents, must adhere to radiation safety guidelines and
work together to promote both patient safety and comfort.
VCUG has been shown to carry a high risk for
inducing patient anxiety and distress, which can
amplify reluctance to undergo similar procedures in
the future. 60 Several studies have shown that long-term
effects of VCUG include behavioral changes, clinginess to parents, and disruption in toilet training and
sleep. 61 Preoperative anxiety in young children is associated with additional postoperative complications. 60
Consequently, researchers have focused on strategies
that help reduce the psychological trauma associated
with VCUG for pediatric patients. Some researchers have proposed that sedation is a
safe, compassionate, and effective means for preventing
emotional stress in most pediatric patients. 60 Typically,
conscious sedation is accomplished using intravenous
or injected midazolam or inhaled nitrous oxide. 60
Conversely, other researchers have proposed that the
child’s and parent’s psychological preparation is equally
important and possibly just as effective at reducing
438
Figure 12. Voiding cystourethrogram (VCUG) of a contrast-filled,
distended urinary bladder (arrow). Image courtesy of the author.
Figure 13.
Bilateral reflux
is noted on this
VCUG image.
Greater reflux is
noted dilating the
right ureter (blue
arrow), although
some reflux also
can be seen on the
left (white arrow).
Image courtesy of
the author.
anxiety. One study found that providing the patient
with information before the examination successfully
reduced distress compared with children who had no
preparation. The study presented the information in
the form of a cartoon and storybook with a photograph
montage explaining the procedure. 61 Regardless of the
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
CE
Directed Reading
Penny
type of psychological intervention, everyone involved in
the procedure should be fully informed about the process and reasons for the examination. Parents should be
encouraged to discuss the components of the examination with their child and should be involved and present
in the examination room when possible. 57 Although highly specific and accurate, the VCUG
also can introduce bacteria into the bladder and exposes the patient to radiation. 47 One Taiwanese national
cohort study claimed that the effective radiation dose
for a VCUG is estimated to be 0.1 mSv to 0.5 mSv. 49
This same study revealed that the overall cancer risk
for a child following VCUG is 1.92 times higher than
for children who have not had a VCUG. The increased
risk includes a 6.19 times higher risk for ovarian and
testicular cancer and a 5.8 times higher risk for lower
urinary tract cancers. 49 Because of this risk, health care
practitioners have tried to reduce radiation exposure to
pediatric patients by using urine sensor devices, pulsed
fluoroscopy, last image-hold technology, automatic
anatomical programming, and decreased total fluoroscopy time. 49
Ultrasonography
Ultrasonography transducers typically emit
high-frequency sound waves between 3.0 MHz and
7.5 MHz. Higher frequency transducers yield higher
resolution images but compromise sound wave penetration. Therefore, the transducer for renal imaging
is chosen partly based on the patient’s body habitus.
In larger patients, a 3.0 MHz to 3.5 MHz transducer might be required, whereas in thin adolescents,
5.0 MHz to 7.5 MHz is preferred.14 With the help of an
acoustic coupling agent, or ultrasound gel, the sonographer manipulates a curved or linear array transducer
on the surface of the child’s abdomen or pelvis to obtain
specific diagnostic images to represent urinary tract
anatomy. The images also can help detect variances,
parenchymal changes, and sonographically identifiable
pathology.14
Ultrasonography delivers no ionizing radiation and
requires no sedation; therefore, this modality often is
appropriate for pediatric imaging and can be the first
choice for many urinary tract indications. It also is
less expensive than other imaging modalities, such as
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
CT and MR imaging, and is performed easily at the
bedside, which can be invaluable in the diagnosis of
pediatric renal disease. Ultrasonography is useful for
identifying anatomical variants of the urinary tract,
congenital malformation, congenital hydronephrosis,
acquired renal obstruction, renal cystic disease, and
tumors. It also is helpful for evaluating children for
signs of infection and vascular compromise, dilatation
of the ureters, abnormalities of the urinary bladder
and urethra, and for assessment of renal transplants
(see Figure 14).14
Although ultrasonography is useful, it has limitations. For example, ultrasonography is not particularly
helpful in evaluating overall renal function, although
the use of Doppler flow pattern assessment can provide
some beneficial information related to obstructive uropathy and transplant assessment.11 However, a typical
urinary tract sonogram has a sensitivity ranging from
11% to 91% and a specificity ranging from 15% to 94%
for diagnosing vesicoureteral reflux.14 Ultrasonography
cannot rule out vesicoureteral reflux and only detects
the condition indirectly. 43 It also is operator dependent,
especially with pediatric patients. In one study of 864
children, ultrasonography performed following an initial urinary tract infection failed to detect changes associated with vesicoureteral reflux and renal damage. 43
Voiding urosonography is similar to the VCUG but
without ionizing radiation exposure. Voiding urosonography uses a sonographic contrast agent (SonoVue, Bracco),
along with saline, injected into the bladder via catheterization.47,62 Sonographic results typically are not considered
dependable; thus, the technique commonly is not used for
routine clinical investigation of reflux.14
Nuclear Medicine
Many radiopharmaceutical agents used in nuclear
medicine that are detected by scintillation or a gamma
camera target specific organs or structures for diagnostic purposes, and others can be used to treat disease. The discharge of ionizing radiation exposes the
patient’s vital organs to radiation, and consequently
can lead to detrimental health effects.2
For pediatric urology patients, nuclear medicine is useful for evaluating renal function in 3 regards: excretion
by glomerular filtration, excretion by tubular secretion,
439
CE
Directed Reading
The Pediatric Urinary Tract and Medical Imaging
radionuclide cystogram also can help detect sporadic
reflux, which might be missed with intermittent fluoroscopy. 64 In addition, the radionuclide cystogram
exposes children to less radiation than does a VCUG. 64
A potential drawback of the radionuclide cystogram
compared with VCUG is poorer spatial resolution. The
physician cannot readily identify bladder and urethral
morphology because of poor spatial resolution, and an
alternate examination might be required. Thus, the
nuclear medicine examination often is seen as a less
cost-effective procedure. 51,64 The use of the bladder
volume-graded direct radionuclide cystogram appears
to be highly sensitive and specific for assessing bladder
function and detecting reflux at various bladder volumes during filling and voiding phases.51
Figure 14. Sonogram revealing evidence of hydronephrosis, which
is indicated by the urine-filled, dilatated renal pelvis (arrow).
Image courtesy of the author.
and renal cortical assessment.63 Technetium Tc 99m
dimercaptosuccinic acid (DMSA) is the most common
radiopharmaceutical used for evaluating the renal cortex for signs of scarring and masses.63 Tc 99m DMSA is
administered to the patient intravenously, and imaging
typically is performed after a 2- to 3-hour delay to allow
the radiopharmaceutical to be absorbed by the cortex.50
Tc 99m DMSA is the agent of choice for diagnosing congenital dysplasia and acute pyelonephritis.37,47
The combination of renal scintigraphy with Tc 99m
DMSA along with urinary tract ultrasonography yields
a negative predictive value of 92%.52 A limitation of Tc
99m DMSA scintigraphy is that the images cannot help
distinguish between long-term scarring and lesions that
will spontaneously resolve. As a result, the examination
is not recommended for evaluating pediatric patients for
vesicoureteral reflux because of a high percentage of falsenegative studies.37,64 Renal scar delineation with scintigraphy cannot be seen for up to 6 months following a case
of acute pyelonephritis as well.7 Although Tc 99m DMSA
can be effective, the radiation dose for the examination is
high, at approximately 1 mSv.43
The radionuclide cystogram is a nuclear medicine
examination used to diagnose vesicoureteral reflux
and is considered more sensitive than VCUG. 64 A
440
Conclusion
Medical diagnostic imaging is invaluable in the diagnosis and treatment of various urinary tract conditions.
Pediatric patients have special needs, and it is incumbent upon imaging professionals to strive to learn more
about the unique diseases of the pediatric patient and to
offer each patient optimal care.
Steven M Penny, MA, R.T.(R), RDMS, is lead instructor
of the medical sonography program for Johnston Community
College in Smithfield, North Carolina. Mr Penny specializes
in abdominal, obstetric and gynecological, and pediatric
sonography.
Reprint requests may be mailed to the American Society
of Radiologic Technologists, Communications Department,
at 15000 Central Ave SE, Albuquerque, NM 87123-3909,
or emailed to [email protected].
© 2016 American Society of Radiologic Technologists
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Clin Pediatr Emerg Med. 2008;9(4):233-237.
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Dewitt T, First L, Zenel J. Pediatrics. Philadelphia, PA: Mosby;
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Philadelphia, PA: Lippincott Williams & Wilkins; 2005:58-78.
42. Alpers C. The kidney. In: Kumar V, Abbas, AK, Fausto N,
eds. Robbins and Cotran Pathologic Basis of Disease. 7th ed.
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43. Montini G, Tullus K, Hewitt I. Medical progress: febrile
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44. Heuther SE. Sturcture and function of the renal and urologic systems. In: Heuther SE, McCance KL. Understanding
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45. Akbar SA, Jafri SZ, Amendola M, Wiater B. Renal infections:
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46.Ansari M. Prophylactic antibiotics in vesicoureteric reflux:
evidence-based analysis. Indian J Uro. 2009;25(2):276-277.
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47. Tullus K. Vesicoureteric reflux in children. Lancet. 2015;385
(9965):371-379. doi:10.1016/S0140-6736(14)60383-4.
48. Bachur R. Pediatric urinary tract infection. Clin Pediatr Emerg
Med. 2004;5(1):28-36.
49. Liao Y, Lin C, Wei C, et al. Subsequent cancer risk of children
receiving post voiding cystourethrography: a nationwide
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56. Callewaert PR. What is new in surgical treatment of vesicoureteric reflux? Eur J Pediatr. 2007;166(8):763-768.
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Kelleher KJ, eds. American Academy of Pediatrics Textbook of
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60. Blumberg K. Sedation and the VCUG. Pediatr Radiol.
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61. Gebarski KS, Daley J, Gebarski MW, et al. Efficacy of a
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62. Sjöberg RL, Lindholm T. A systematic review of age-related
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(VCUG). Eur Child Adolesc Psychiatry. 2005;14(2):104-105.
63. Lai KN. A Practical Manual of Renal Medicine: Nephrology,
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2006;36(suppl 2):185-191.
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
Directed Reading Quiz
16802-02
13802-03
1.5
2.0 Category A+ credits
Expires April 30, 2019*
2015*
The Pediatric Urinary Tract and
Medical Imaging
To earn continuing education credit:
 Take this Directed Reading quiz online at www.asrt.org/drquiz.
 Or, transfer your responses to the answer sheet on Page 446
410Mand
andmail
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POBox
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New and rejoining members are ineligible to take DRs from journal issues published prior to their most recent join date unless
they have purchased access to the quiz from the ASRT. To purchase access to other quizzes, go to www.asrt.org/store.
*Your answer sheet for this Directed Reading must be received in the ASRT office on or before this date.
Read the preceding Directed Reading and choose the answer that is most correct based on the article.
1. The kidneys filter the body’s entire blood volume
approximately every______ minutes.
a.2
b.10
c.40
d.90
4. ______ is likely caused by a urinary tract obstruction during fetal development.
a. Autosomal dominant polycystic kidney disease
b. Medullary nephrocalcinosis
c. Autosomal recessive polycystic kidney disease
d. Multicystic dysplastic kidney disease
2. The site at which the ureter meets the bladder is
called the ______ junction.
a.ureterovesical
b.ureteropelvic
c.ureterourethral
d.trigonalvesicular
5. Which is the most common congenital anomaly of
the urinary tract?
a. vesicoureteral reflux
b. duplication of the renal collecting system
c. horseshoe kidney
d. ureteropelvic junction obstruction
3. The metanephric kidneys initially develop within
the:
a. fetal chest.
b. fetal pelvis.
c. base of the umbilical cord.
d.cloaca.
6. Which is the most common cause of bladder outlet
obstruction in newborn boys?
a. vesicoureteral reflux
b. horseshoe kidney
c. posterior urethral valves
d. Beckwith-Wiedemann syndrome
continued on next page
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
443
Directed Reading Quiz
7. Which of the following renal tumors is the most
common renal malignancy in children?
a. nephroblastoma (Wilms tumor)
b.neuroblastoma
c.angiomyolipoma
d.hemangioma
8. Which is the most common abdominal malignancy
in newborns?
a. Wilms tumor
b.angiomyolipoma
c.neuroblastoma
d. tuberous sclerosis
12. A voiding cystourethrogram is the most frequently
performed fluoroscopic examination in the
pediatric radiology department for investigating
lower urinary tract disease.
a.true
b.false
!
Your post-test is now complete.
The ARRT now requires only 8 questions per CE credit.
For additional information, read the recent ASRT Scanner
story at asrt.org/as.rt?BvrzKx.
9. Which bacteria is implicated in nearly 80% of
urinary tract infections (UTIs)?
a. Enterococcus
b. Klebsiella
c. Streptococcus
d. Escherichia coli
10. Scarring of the renal parenchyma from conditions,
such as congenital dysplasia, ultimately can lead to:
1. adult hypertension.
2. end-stage renal disease.
3. toxemia during pregnancy.
a.
b.
c.
d.
1 and 2
1 and 3
2 and 3
1, 2, and 3
11. To prevent UTIs, children with known vesicoureteral reflux disease and a history of UTIs have been
managed mostly with:
a. renal transplant.
b. prophylactic antibiotic medications.
c. surgical resection.
d. behavioral modification therapy.
444
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
✁
Carefully cut or tear here.
JRCERT Update
My Journey: Serving on the
JRCERT Board of Directors
Debra Poelhuis, MS, R.T.(R)(M)
T
he Joint Review Committee on Education in
Radiologic Technology staff asked me to write
about my time on the JRCERT Board of
Directors, 2009 through 2015. I am honored to
share my recollections of what was a tremendously
rewarding experience for me.
An Opportunity to Give Back
As I advanced through my career, which spans nearly
44 years, I always looked for something to keep me
captivated and engaged in the profession I so love. I
learned multiple imaging modalities, earned a master’s
degree, coauthored 2 textbooks, and held positions in
professional organizations. Maybe most importantly, I
met some wonderful colleagues and guided numerous
students into this career, with many of them becoming
great friends.
When the call went out from the American Society
of Radiologic Technologists (ASRT) in 2008 seeking
candidates for nomination to the JRCERT Board of
Directors, I decided to throw my hat into the ring. I
was well aware of the JRCERT, as I had been a program
director for 18 years. I knew many of the JRCERT staff
as well as its chief executive officer. Being active in the
ASRT, I also knew individuals who had served on the
JRCERT board. I felt as if I had something more to offer
my profession, and it was the right time in my career to
serve in this capacity. So, needless to say, when I ultimately was selected by the JRCERT for appointment as
a director, I was excited, albeit a little nervous.
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
Baptism by Fire
When I first joined the board, the process for reviewing accreditation documents was not as automated
or technologically enhanced as it is now. Before my
first meeting, I received 2 boxes filled with self-study
reports, interim reports, progress reports, and substantive changes. My instructions were to read them all,
make notes, mail them back, and be ready to discuss
them at the board meeting in Chicago—a real baptism
by fire! Eventually, we started receiving reports on flash
drives, then on our tablets and computers via links to
the JRCERT Web site.
The board also moved from having 2 meetings a
year, both of which were face-to-face in Chicago, to
augmenting them with monthly meetings held via
webinar. The meetings in Chicago entailed interacting with JRCERT staff, dealing with the business and
financial aspects of the JRCERT, evaluating the chief
executive officer, assisting with personnel issues, conducting strategic planning, interviewing prospective
board members, reviewing program documents, and
determining final accreditation awards.
My Experiences on the Board
Board appointments are for 3 years, with a possible extension for an additional 3 years. I served
6 years, moving from first vice chair to chair my
final year. My predecessor, Deborah Gay Utz, MEd,
R.T.(R), radiography program director at Gadsden
State Community College, Gadsden, Alabama, was
447
JRCERT Update
My Journey: Serving on the JRCERT Board of Directors
a terrific mentor who prepared me well for the chair
position.
It was a busy and exciting time for me. As chair I
conducted board meetings, of course, but I also represented the board at national and state professional
meetings across the country, meetings that included
the Association of Collegiate Educators in Radiologic
Technology, the Association of Educators in Imaging
and Radiologic Sciences Inc, and the ASRT. In addition, I defended the JRCERT’s petition for reaccreditation to the Council for Higher Education Accreditation
Committee on Recognition in Washington, DC.
During this presentation, it was comforting to have
the support of Leslie Winter, MS, R.T.(R), JRCERT
chief executive officer, and Darcy Wolfman, MD, current board treasurer. As needed, I assisted with unannounced site visits.
I completed my term in April 2015. Those were 6 of
the most precious and rewarding years for me in this
profession. I always felt a sense of pride with each class
I graduated during my tenure as a program director, but
this achievement felt different. This was something I
did for the profession and for myself. Throughout my
term, I had terrific support from my JRCERT family,
my husband, my program faculty, my students, and
most importantly my employer, Montgomery County
Community College, in Pottstown, Pennsylvania. They
all encouraged and praised my participation on the
JRCERT board and allowed me the freedom to commit
the time and travel required for board activities.
Looking back, I feel we were the hardest working
and most professional board I have ever served on. We
worked hard, we laughed even harder, and we always
respected one another’s opinions. I made friends for a
lifetime.
My advice to others thinking of giving back to the
profession? Go for it! You will not be disappointed.
Debra Poelhuis, MS, R.T.(R)(M), is a former chair of
the board of directors for the Joint Review Committee on
Education in Radiologic Technology. She also is clinical
coordinator for Montgomery County Community College in
Pottstown, Pennsylvania.
448
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
In the Clinic
Radiographic Techniques in the 45°
Posteroanterior Oblique Projection
of the Hand
Carol Rose, MBA, BSc, DCR(R), DipEd
Jannet McIntosh, MSc, BSc, CDDR
A
pplying disparate radiographic positioning
techniques for any body part affects the accuracy, comprehensiveness, and consistency of
patient diagnosis and treatment. Lack of standardization in positioning reduces diagnostic efficiency
and is not in patients’ best interest.1 Radiologists in
Jamaica have expressed concern about the lack of standardization of imaging techniques among radiologic
technologists in local practice. Students in the local
diagnostic imaging program also have raised concerns
regarding differences in positioning techniques among
clinical placement sites, imaging technologists within a
single site, laboratory instructors, and lecturers of radiographic positioning. This disparity affects students’
learning as well as clinical and classroom assessment.
One such disparity in the basic techniques is the 45°
posteroanterior (PA) oblique projection of the hand.
Basic positioning techniques in the oblique projection
vary between having the digits slightly flexed with
their tips placed in contact with the image receptor
or curled over nonopaque support2-6 and having them
fully extended and parallel to the image receptor.7-13
One proponent of the extended digits position as the
basic technique has cited the disadvantage of using the
fingers as props, in that this action closes the interphalangeal joints and foreshortens the phalanges, and is to
be applied when the metacarpals only are of interest.7
Alternately, an advocate of the slightly flexed position
of the digits as the basic technique suggests the use of
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
foam support for the digits when joint spaces are to be
imaged. 5
Implicit in the justification of a practice and optimization of patient protection is that diagnostic
images produced in a radiology department should be
of high quality and provide the necessary diagnostic
information. Image quality varies according to the
technique used, from exposure factors and filtration,
to positioning.1
Disparities also exist in the beam-centering practices
employed for the projection, which include the use of a
central ray directed perpendicular to the image receptor
and centered to the head of the fifth metacarpal bone or
fifth metacarpophalangeal joint,2,14 or to the head of the
third metacarpal bone or third metacarpophalangeal
joint. 3-8,10-13 Accuracy in the direction and centering of
the central ray is one factor that determines whether
the anatomy is aligned properly and that an open joint
space or fracture line is demonstrated. The central ray
or divergent rays must be parallel with the fracture
line or joint space of interest. Failure to accomplish
this alignment results in a closed joint or poor fracture
visualization because the surrounding structures are
projected into the space or over the fracture.11 Tube
angulation causes a shift in the projection of anatomical
structures on the image and can be used to advantage in
specific examinations. 5,15,16
The variations in practice appear to have their genesis in radiographic positioning texts and should be
449
In the Clinic
Radiographic Techniques in the 45° Posteroanterior Oblique Projection of the Hand
investigated. Understanding the reasons for the variations helps determine stakeholder perceptions of their
effect on patient diagnosis and facilitates the need for
standardization of imaging practice.
Literature Review
Despite the proliferation of advanced imaging technologies, routine radiography remains the modality
of choice to evaluate conditions of the extremities,
including the hand and wrist,17,18 and it should be the
initial study obtained (in conjunction with clinical
presentations) to direct further imaging when necessary.16 As with radiography of any body part, multiple
projections are necessary to delineate the anatomy.
Hand radiographs at right angle projections (PA and
lateral) are not always useful if structures are superimposed in the lateral view. Thus, the oblique view often
is used, but when a certain portion of the hand needs
to be examined, specific views should be obtained.
For example, the anteroposterior (AP), oblique, and
lateral projections of the fingers can be obtained when
they are of interest.19 The oblique projection has the
advantage over the lateral projection because it shows
the individual bones separately. It is used to show
details of injuries observed in the lateral projection, to
demonstrate minor cracks in the bones, and to show
pathological conditions.2
DeSmet et al confirmed the importance of the
oblique projection of the extremities through prospective studies of consecutive radiographic examinations
of the distal extremities (foot, toes, wrist, hand, fingers,
and thumb) in trauma patients in which each examination was interpreted and given a diagnostic certainty
score using the lateral and PA or AP views only, and
then scored again with the oblique view added. The
addition of the oblique view changed the interpretation
in 70 (4.8%) of the 1461 examinations and increased
diagnostic confidence.20
Incidental findings in radiographic imaging also
raise patient care concerns.21 Incidental findings are
any abnormality not related to the illness or injury
that prompted the diagnostic imaging test, and a high
percentage of such findings have been identified in
imaging tests, especially for patients with nonspecific
initial diagnoses.22 Oblique views are considered useful
450
when further clarifications are required 23 and other
findings,17 such as the identification of small erosions,
appear.24 Most of the common skeletal dysplasias have
manifestations in the hand, and hand bones also are
affected in many systemic hematological and metabolic conditions. In addition, some conditions have
characteristic findings that lead to a diagnosis that can
be confirmed on a single hand radiograph when those
findings are present.25
Basic Positioning
Disparities in basic positioning of the 45° PA oblique
projection of the hand vary in the literature between
having the digits slightly flexed with their tips placed in
contact with the image receptor2-6 and having the digits
fully extended and parallel to the image receptor.7-10,11,13,28
Some texts have described a single basic positioning
method,2,8,10,11,28 and others have alternated between
both positions of the fingers as the basic and the
history-dependent alternative. 3-7,9,12,13 For example, the
technique employing slightly flexed fingers in contact
with the image receptor is justified under conditions for
which the digits are not of concern.2,5 Other texts have
supported positioning with the digits extended as the
basic position for reasons of demonstrating interphalangeal joints, metacarpophalangeal joints, phalanges,
carpals, joints of the wrist, and pathological processes
such as osteoporosis and osteoarthritis.7,8,11-13
Beam Direction and Centering
Centering points for the oblique hand also vary
among texts. Examples include employing a combination of a central ray directed perpendicular to the
image receptor and centered to the head of the fifth
metacarpal bone.2,14 The disadvantage of this technique is that it requires a wide beam aperture to cover
the entire hand, leaving a significant portion of unused
beam extending beyond the anatomic medial border
of the hand, with implications for radiation protection. However, this combination of beam direction
and centering point is thought to take advantage of the
geometry of the divergent beam to project structures
elevated from the image receptor with as little overlap
as possible, especially in the demonstration of joint
spaces.
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
In the Clinic
Rose, McIntosh
Clark recommended the use of a vertical beam
centered on the head of the fifth metacarpal or alternatively angling the vertical beam from this original
centering point (ie, the head of the fifth metacarpal)
toward the head of the third metacarpal, thus reducing
the covering aperture of the beam by 50%.2 This alternative becomes the basic beam-centering technique
in subsequent publications of the same text, 27 indicating that positioning techniques undergo revision over
time. Central ray angulation sometimes is required
to eliminate superimposition of objects that typically
obstruct visualization of the area of interest15 and,
when necessary, to avoid stacking a curved structure
on itself, to project angled joints, or to project angled
structures without foreshortening or elongation, with
the aim to have the principal beam of x-rays at a right
angle to the structure, projecting it with the least
amount of distortion.16
The most common combinations of beam direction
and centering point in recent literature are the use of a
beam directed perpendicular to the image receptor and
centered on the head of the third metacarpal or third
metacarpophalangeal joint.3-8,10-13 This combination also
has the effect of significantly reducing the beam aperture.
Another combination offered in the literature includes a
perpendicular beam centered midway between the second and third metacarpophalangeal joints.9
Methods
Survey instruments were distributed at 2 medical
imaging sites to 55 respondents comprising 45 diagnostic
imaging technologists and 10 consultant radiologists
with a total of 36 instruments returned (a 66% response
rate). Technologists accounted for 33 (92%) returned
instruments and radiologists for 3 (8%). Nonprobability
purposive sampling technique was used to obtain the
sample. This type of sampling is judgmental and falls
under the broad category of nonrandom sampling.28 The
researchers’ experience in the field and knowledge of the
population and its characteristics influenced this choice.
The survey instrument for radiologists varied slightly
from the instrument for imaging technologists with a few
questions common to both. Because of the low response
rate from radiologists, only questions common to both
groups were reported.
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
The 2 sites were selected because they provide sufficient exposure of the respondents to diagnostic imaging
of the hand. Statistics provided by the chief radiographer
for one radiology department indicated that for the period 2010 to 2012, the department performed, on average,
20 609 routine radiographic examinations of the extremities annually, representing approximately 30% of the
average annual total of 69 319 radiographic examinations.
Similarly, statistics provided by the chief radiographer of
the second department indicated that in the same 3-year
period, the department performed, on average, 8429 routine radiographic examinations of the extremities, representing approximately 16.4% of its average annual total of
51 402 radiographic examinations.
The records obtained from both departments did
not provide a breakdown of the specific examinations
of the extremities, but anecdotal evidence suggested
that radiographic examinations of the hand would constitute a significant portion of the studies. Both sites
have quality control processes in which all radiographs
are checked by a senior radiographer before dispatch to
radiologists. Descriptive statistics method using SPSS
software (IBM) was used to analyze the data.
Results
Salient findings of the survey indicated disparities
in techniques employed in positioning for the oblique
projection of the hand, the influences determining the
imaging technique used, and opinions on the need for
standardization of practice among imaging technologists at both sites.
The most common position employed for the 45°
oblique projection of the hand was the slight curling of
the digits, followed by extending the digits, alternating
between those positions, and employing other techniques such as the “fan” positioning of the digits when
they are of interest (see Figure 1).
Open-ended responses regarding reasons for
employing the curled fingers included:
■ Maintaining stability of the hand.
■ Maintaining the position as a natural resting
position and natural obliquity of the hand.
■ Preserving patient comfort.
■ Preventing superimposition of the digits.
■ Opening joint spaces.
451
In the Clinic
Radiographic Techniques in the 45° Posteroanterior Oblique Projection of the Hand
■ Separating the phalanges and metacarpals.
■ Obtaining a projection almost at right angles to
the PA projection to demonstrate all bones without superimposition.
■ Demonstrating spiral fractures of the metacarpals
and phalanges.
■ Visualizing anatomy without soft tissue overlap.
■ Doing what they were taught.
Although some of the reasons were logical, all are not supported in the literature and might have been derived from
technologists’ accumulated experience with positioning
the hand over time. Slightly curling the digits is supported
in the literature only when the digits are not of interest.7
Reasons given by respondents in support of extending the digits were more congruent with the literature
and included demonstrating the interphalangeal joints,
preventing foreshortening of bones, and that the position brought structures closer to the image receptor.
Respondents indicated that their choice of alternating between the curled and extended position of the
digits was not linked to one position or another of the
digits. Rather, they supported their choice with considerations of patient care and technical factors. Patient
care considerations included facilitating the patient’s
condition and ability to assume the required position,
patient comfort, and patient age. Technical factors
included avoiding superimposition of the heads of the
third through fifth metacarpals and visualizing the
metacarpals and metacarpophalangeal and interphalangeal joints. The literature supports alternating between
both positions of the digits for reasons of demonstrating
specific areas of interest.
The choice of a central ray directed perpendicular
to the image receptor was found to be consistent across
all imaging technologists. Most technologists (66%)
chose to center the beam at the region of the head of the
third metacarpophalangeal joint/metacarpal head for
reasons of effective collimation. Centering between the
heads of the second and third metacarpals accounted
for 21% of responses. A significant variation (9%) from
these 2 most common centering points is centering the
beam at the region of the fifth metacarpophalangeal
joint/metacarpal to capitalize on the divergent rays to
separate the metacarpals and demonstrate joint spaces.
Ninety-seven percent of respondents indicated that the
452
Where the PA oblique projection is employed,
what position of the fingers do you employ?
3%
12%
18%
67%
Slightly curled with
fingers in contact with
the image receptor
Alternate between
extended and curled
Fully extended
Other
Figure 1. Percentages of technologists who employ varying
positioning techniques for the 45° posteroanterior (PA) oblique
projection of the hand.
positioning of the digits was important to diagnosis to
How important
is the
position
of the
varying degrees
(see Figure
2). When
asked
to select
digits
in
the
diagnosis
of
the
oblique
hand?
the structures of interest in the PA oblique projection
of the hand, 81% of respondents
(technologists and
3% 3%
radiologists) agreed that all structures of the hand are
important in the imaging process.
The greatest influences on the positioning techniques used by technologists were derived from department routine and8%
clinical practicum (see Figure 3).
Twenty-four percent of respondents indicated combinations of influences on their practice, and 15% reported
being influenced by laboratory simulation
47%and classroom lectures.
On the question of the need for standardization
of practice, 72%39%
of all respondents agreed that there
is a need to standardize positioning for the oblique
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
Slightly curled with
fingers in contact with
the image receptor
Alternate between
extended and curled
Fully extended
Other
Department routine
Simulations
Clinical practicum
Lectures
Combinations
response
In No
the
Clinic
Rose, McIntosh
important
the position
of the
WhereHow
the PA
oblique is
projection
is employed,
digits
in the of
diagnosis
of the
hand?
what
position
the fingers
do oblique
you employ?
3%
3% 3%
Which of the following was the most influential
in guiding your practice in positioning and
beam centering for the hand?
3% 3%
12%
8%
12%
30%
47%
18%
39%
67%
24%
27%
Important
Slightly
curled with
fingers in contact with
the Most
imageImportant
receptor
Of little
importance
Alternate
between
extended and curled
No response
Department routine
Simulations
Clinical practicum
Lectures
Fully
extended important
Moderately
Other
Combinations
No response
Figure 2. Respondents’ opinions about the importance of the
Figure 3. Influences that guide positioning and beam centering
projection of the hand, whereas 25% disagreed (3%
important
is the position
of thecommon
did notHow
respond
to the question).
The most
digitsprovided
in the diagnosis
of support
the oblique
hand?
reasons
by those in
of standardization included:
3%
3%
■ Positioning’s
impact on diagnosis.
■ Uniformity and consistency of practice.
■ Setting protocol and standards for teaching.
■ Preventing variations in the presentation of
anatomy.8%
Most respondents who supported standardization were
in favor of all stakeholders guiding the standardization
process including radiologists, referring
physicians, imag47%
ing technologists, lecturers of radiographic positioning,
and authors of radiographic texts. Opponents of standardizing practice cited
39%varied patient conditions, the anatomy
of interest, and varied patient body types as reasons in
support of nonstandardization. Some also noted that
departments should decide their own protocol.
position of the digits in diagnosis of the hand.
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
practice among technologists.
Conclusion
In the absence of department protocols for conducting the 45° PA oblique projection of the hand, technologists employ disparate positioning and beam-centering
techniques. Addressing this issue requires collaboration
by all stakeholders in the process.
In-depth laboratory experiments and image analysis
are needed to determine the extent to which current
practices in positioning techniques employed in the
45° PA oblique projection of the hand affect diagnosis.
However, this study, although limited by sample size
and not generalizable, breaks ground for the investigation of disparities in practices in this and other imaging
453
In the Clinic
Radiographic Techniques in the 45° Posteroanterior Oblique Projection of the Hand
examinations with the goal of moving toward standardization in teaching and clinical practice.
Carol Rose, MBA, BSc, DCR(R), DipEd, and Jannet
McIntosh, MSc, BSc, CDDR, are assistant lecturers for
the School of Medical Radiation Technology in the Faculty
of Medical Sciences, University of the West Indies, Mona,
Jamaica, West Indies.
References
1. Rainford LA, Al-Qattan E, McFadden S, Brennan PC. CEC
analysis of radiological images produced in Europe and Asia.
Radiography. 2007;13(3):202-209.
2. Clark KC. Positioning in Radiography. Vol 1. 9th ed. London,
England: Ilford; 1973:4-5.
3. Merrill V. Atlas of Roentgenographic Positions and Standard
Radiologic Procedures. 4th ed. St Louis, MO: Mosby; 1975:33.
4. Bontrager KL, Anthony BT. Textbook of Radiographic
Positioning and Related Anatomy. 2nd ed. St Louis, MO:
Mosby; 1987:96.
5. Cullinan AM. Optimizing Radiographic Positioning. New York,
NY: Lippincott Williams & Wilkins; 1992:26, 58.
6. Dowd SB, Wilson BG. Encyclopedia of Radiographic
Positioning. Philadelphia, PA: Saunders; 1995:132.
7. Bontrager KL, Lampignano JP. Textbook of Radiographic
Positioning and Related Anatomy. 7th ed. St Louis, MO:
Mosby Elsevier; 2009:148.
8. Greathouse JS. Delmar’s Radiographic Positioning and
Procedures. Vol 1. Albany, NY: Thomson Delmar Learning;
1997:110-111.
9. Cornuelle AG. Competency Manual for Radiographic Anatomy
and Positioning. Stamford, Connecticut: Appleton and Lange;
1998:39.
10. Eisenberg RL, Dennis CA, May CR. Radiographic Positioning.
Boston, MA: Little, Brown & Company; 1995:51.
11. McQuillen-Martensen KM. Radiographic Image Analysis. 3rd
ed. St Louis, MO: Saunders; 2011:180-183.
12. Ballinger PW, Frank ED. Merrill’s Atlas of Radiographic
Positioning and Radiologic Procedures. Vol 1. 9th ed. St Louis,
MO: Mosby; 1999:106-107.
13. Ballinger PW. Merrill’s Atlas of Radiographic Positions and
Radiologic Procedures. Vol 1. St Louis, MO: Mosby; 1982:122125.
14. Bryan G. Diagnostic Radiography. 3rd ed. London, England:
Churchill Livingstone; 1979.
454
15. Fauber T. Radiographic Imaging and Exposure. 3rd ed.
St Louis, MO: Mosby; 2009:126.
16. Levine SM, Lambiase RE. Ancillary radiographic projections
of the hand and wrist. J Am Soc Surg Hand. 2002;2(1):1-13.
17. Peterson JJ, Bancroft LW, Kransdorf MJ. Principles of bone
and soft tissue imaging. Hand Clin. 2004;20(2):147-166.
18. Guermazi A, Burstein D, Conaghan P, et al. Imaging in osteoarthritis. Rheum Dis Clin North Am. 2008;34(3):645-687.
doi:10.1016/j.rdc.2008.04.006.
19. Poznanski AK. The Hand in Radiologic Diagnosis With
Gamuts and Pattern Profiles. Vol 1. Philadelphia, PA:
Saunders; 1984:6.
20. DeSmet AA, Doherty MP, Norris MA, Hollister C, Smith
DL. Are oblique views needed for trauma radiography of the
distal extremities? AJR Am J Roentgenol. 1999;172(6):15611565.
21. Sperry JL, Massaro MS, Collage RD, et al. Incidental radiographic findings after injury: dedicated attention results in
improved capture, documentation and management. Surgery.
2010;148(4):618-624. doi:10.1016/j.surg.2010.07.017.
22. Lumbreras B, Donat L, Hernandez-Aguado I. Incidental
findings in imaging diagnostic tests: a systematic review. Br J
Radiol. 2010;83(988):276-289. doi:10.1259/bjr/98067945.
23. Yoong P, Goodwin RW, Chojnowski A. Phalangeal fractures
of the hand. Clin Radiol. 2010;65(10):773-780. doi:10.1016/j
.crad.2010.04.008.
24. Perez-Ruiz F, Dalbeth N, Urresola A, de Miguel E,
Schlesinger N. Imaging of gout: findings and utility. Arthritis
Res Ther. 2009;11(3):232. doi:10.1186/ar2687.
25. Chavhan GB, Miller E, Mann EH, Miller SF. Twenty classic hand radiographs that lead to diagnosis. Pediatr Radiol.
2010;40(5):747-761. doi:10.1007/s00247-009-1520-2.
26. Bostock S. Fractures of the carpus and hand. Surgery.
2010;28(2):70-74. doi:10.1016/j.mpsur.2009.10.021.
27. Whitley A, Sloane C, Hoadley G, Moore A, Alsop C. Clark’s
Positioning in Radiography. 12th ed. London, England: CRC
Press; 2005.
28. Babbie E. Survey Research Methods. 2nd ed. Belmont, CA:
Wadsworth; 1990:193.
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
Professional Review
Advantages and Disadvantages of
Screening Breast Ultrasonography
Lisa Warner, BS, R.T.(R)(M)
F
orty percent of women who have an annual mammogram are found to have dense breast tissue.
Increased breast density has the potential to mask
small abnormalities, but screening breast ultrasonography is effective in finding even small tumors.1
Berg et al evaluated screening methods for effectiveness in finding occult breast cancers in a study in which
2662 women with a minimum of 50% dense breast tissue underwent a series of randomized testing with mammography, ultrasonography, and magnetic resonance
(MR) screenings each year. According to the study, the
combination of annual mammography with screening
breast ultrasonography resulted in a 76% sensitivity rate
vs 52% with screening mammography alone.2
Furthermore, this study indicated that earlier
detection of node-negative breast cancers is linked to
using supplemental screening breast ultrasonography.
Discovering breast cancer before it reaches the lymph
nodes can decrease mortality rates significantly in
women with dense breast tissue.2 Of the 32 cases discovered on screening breast ultrasonography alone,
94% had a pathological confirmation of invasive carcinoma with an estimated tumor size of less than 1 cm.
More importantly, of those 32 participants, 96% were
determined to have no pathological node involvement.2
Another study from the American College of
Radiology Imaging Network evaluated nearly 7000 mammography studies of participants who had either a previous history of breast cancer or an intermediate risk for
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
developing breast cancer.2 A final imaging review of those
with a history of breast cancer determined that if screening breast ultrasonography had been employed in combination with yearly mammography, the results could have
limited the disease’s extent and reduced treatment costs.2
However, collaborative initiatives from researchers
in the Netherlands and the United States revealed disadvantages of screening breast ultrasonography. 3 The
purpose of their study was to provide data to support
cost efficiency, earlier diagnosis, and biopsies suggested
because of false-positive occurrences. Out of 1000 participants who met the breast density criteria, only 0.36
incidences were prevented because of incorporating
adjunct screening ultrasonography. Of those 0.36 incidences, only 1.7 quality-adjusted life years were added,
leaving the supplementary cost for testing much higher
than the benefit believed.3 The cost of complementary
screening of those 1000 participants equated to the
ratio of $325 000 per quality-adjusted life years extended. This was viewed as a tremendous cost of care vs the
realistic value achieved. 3
Researchers determined that employing supplemental breast ultrasonography within this patient population
can increase biopsy prevalence, added costs for treatment, and a higher rate of false-positive examinations.3
According to Kuehn, women with dense breast tissue
do not have an increased risk of breast cancer–related
deaths.4 A National Cancer Institute study comparing
outcomes of 9232 women with breast cancer based on
455
Professional Review
Advantages and Disadvantages of Screening Breast Ultrasonography
breast density and other factors found that 889 deaths
occurred within 6.6 years after diagnosis. Of those
deaths, breast density was not an associated factor in
relation to their mortality.4
Traditionally, diagnostic breast ultrasonography is used
to evaluate abnormal imaging results or a palpable lesion.
However, on September 18, 2012, the U.S. Food and
Drug Administration (FDA) approved the first screening breast ultrasound machine, the somo-v automated
breast ultrasound system (ABUS, GE Healthcare) for
nonsymptomatic high-risk patients who demonstrate
heterogeneously dense fibroglandular breast tissue, Breast
Imaging-Reporting and Data System (BI-RADS) category 1 or 2.5 The ABUS helps radiologists detect small hidden lesions in dense breast tissue,6 providing a secondary
imaging modality to complement the traditional screening mammogram for these patients.7
Risk Factors
The purpose of the FDA’s approval of screening
breast ultrasonography is to foster a reduction of disease
prevalence in patients at higher risk of developing a
breast cancer. Women with dense breast tissue should
discuss their medical history with their primary care
provider, in particular, their personal or family history
of genetic mutations such as BRCA1, BRCA2, Cowden
disease, or Li-Fraumeni syndrome.8 BRCA1 and BRCA2
suppress tumor growth, and those with a mutation in
these genes have a greater than 80% chance for breast
and ovarian cancer.8 Cowden disease is a genetic disorder that increases the risk of breast and thyroid cancer.8 Li-Fraumeni syndrome is a rare genetic condition
that causes multiple types of malignancies as a result
of an alteration in the p53 tumor suppressor gene.8
Hereditary breast cancers account for 5% to 10% of all
breast cancer diagnoses.8
Other risk factors are age, ethnicity, multiple benign
breast biopsies, and dense breast tissue.8 As a woman
ages, her risk of breast cancer increases. Women of
Asian, Hispanic, and Native American decent have
an overall lower risk of acquiring breast cancer. White
women have a higher risk of developing breast cancer
than any other ethnicity; however, African American
women have a greater incidence of breast cancer-related
deaths.8 Benign breast conditions indicate proliferative
456
cellular growth and can increase a woman’s risk of
developing breast cancer. More often these benign
breast conditions possess only a slightly increased risk.
Even so, it is important to maintain proper imaging
protocols following biopsy procedures.8 According to
the American Cancer Society, women with dense breast
tissue are 1.2 to 2 times more likely to develop breast
cancer than those with moderately fatty breasts.8
Indications
Reporting breast tissue density in every mammography report and patient result letter provides clear indication to ordering physicians and patients about effective
screening measures.9 More than half of U.S. states have
introduced legislation for mandatory breast density
notification to inform patients who are at higher risk
of breast cancer, and 24 states have passed it. 4 Sharing
the complete assessment of a woman’s risk allows her to
make an informed decision about what type of breast
screening she should choose.10
A description of a patient’s breast tissue pattern can
indicate the potential for abnormalities hidden by dense
tissue.9 The Figure shows the 4 categories (a, b, c, d)
of breast tissue composition defined by the American
College of Radiology. These descriptions are included in
the mammography report and should not be confused
with BI-RADS numbers 1 through 6. The BI-RADS
numbers are the radiologist’s final assessment of the
examination.9
Typically, additional imaging other than screening
mammograms is required because of dense breast tissue. Patients with fatty breasts have a lower incidence of
returning for further imaging assessment.5,7 If a radiologist determines a suggestive finding is present, but no
abnormality is detected after additional imaging, this
is considered a false-positive result.9 Most false-positive
results occur in patients with extremely dense breast
tissue, a personal or family history of breast cancer, or
prior multiple breast biopsies. False-negative results
also occur when an occult tumor is missed on a screening mammogram.11 Twenty percent of all diagnosed
breast cancers are missed at the time of screening.
Consequently, patients with dense breast tissue or who
are genetically at higher risk should be screened routinely and follow-up on any abnormal findings.11
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
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A
B
C
D
Figure. Four categories of breast composition. A. The breasts are almost entirely fatty. B. Scattered areas of fibroglandular tissue are
present. C. Tissue is heterogeneously dense and might obscure masses. D. The breast tissue is extremely dense, which lowers the sensitivity
of mammography. Reprinted from BI-RADS Atlas 5th edition with permission of the American College of Radiology (ACR). No other
representation of this material is authorized without expressed, written permission from the ACR.
Using ABUS as a screening method could reduce the
incidence of node-positive tumors, potentially increase
survival rates, and reduce the use of ionizing radiation
for follow-up imaging. In combination with yearly mammography, this screening tool can increase the rate of
breast cancer detection by 35.7% in women with dense
breast tissue.7 ABUS use is indicated in asymptomatic
patients whose previous mammography findings were
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
normal or benign resulting in a BI-RADS category 1
or 2 classification.5 The somo-v ABUS with advanced
3-D technology can provide a detailed assessment
of the breast in less time than the traditional 2-D
handheld unit.5 In patients with prior breast biopsies,
screening breast ultrasonography is not recommended
because their tissue is somewhat distorted and reduces
the competency of the test.
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Professional Review
Advantages and Disadvantages of Screening Breast Ultrasonography
The ABUS system enhances imaging metrics and
is equipped with a transducer that has a higher frequency value, which decreases the time needed to scan
a patient. A standard application of gel together with
a disposable mesh covering against the patient’s skin
helps maintain a uniform seal between the breast and
the transducer for increased image quality.10 The images
display a visualization of the patient’s anatomy from the
skin’s surface to the chest wall.5
Consistent positioning and scanning techniques are
essential to optimize reliable interpretation, duplication, and uniformity of every examination. The use of
the ABUS system can improve the sensitivity of annual
imaging in patients with dense breast tissue. Used in
combination with mammography, this screening device
can assess dense breasts effectively and provide an additional benefit to those in this high-risk population.2,5-7
Consumer Perceptions
Public opinion regarding FDA approval of the ABUS
machine for screening breast ultrasonography has had
mixed reactions. Many patients are unaware of their
breast tissue type and the effectiveness of their screening
mammogram.12 Although more women with dense breast
tissue now understand their increased risk, it seems many
are not informed about mammography’s limitations in
imaging this tissue type.12 Even though supplemental
imaging, such as digital breast tomosynthesis, has
become more acceptable, public awareness of screening
breast ultrasonography still is limited.
Some believe that any medical device approved by
the FDA should be accessible to all.13 However, the
availability of screening breast ultrasonography is lacking even though the FDA studies were clear that women
with breast density category types c and d could benefit
from this added test.5 Once breast density awareness
becomes common knowledge, more women might
advocate for such testing as a means to decrease mortality rates by finding disease much earlier.13
Advantages and Disadvantages
The most obvious advantage associated with the
FDA approval of the ABUS system is decreasing mortality rates in high-risk patients. This is noteworthy
because most patients in this population have a 4 to 6
458
times greater calculated risk than women with minimal dense tissue.13 Typically, women with dense breast
parenchyma have a rigorous treatment plan because
most tumors have a high incidence of a cancer reoccurrence. Therefore, it is essential to diagnose these patients
before their tumor size becomes larger than 2 cm.5
Another advantage is the decrease in follow-up
imaging after screening mammography or a BI-RADS
0 result. Incorporating supplemental breast ultrasonography as a same-day option could decrease patient
anxiety, increase patient compliance, and reduce falsepositive or false-negative outcomes. Additional screening protocols can reduce subsequent treatment costs
as well.5,7,13 When alternative screening measures are
part of a comprehensive annual checkup, the cost more
than justifies the savings of earlier detection.13 However,
insurance approval and designated reimbursements
must take place before added screening examinations
can become routine for these patients.13
Several concerns associated with the FDA approval
have limited the number of patients screened. Lack of
insurance coverage for routine screening, longer examination times, and inconsistent scanning methods are
associated with the modality’s limited use. Most insurance companies view screening breast ultrasonography
as experimental, and reimbursement remains minimal.13
Only a small percentage of medical insurers cover ultrasonographic screening in asymptomatic patients despite
its demonstrated efficacy in breast cancer detection.12 If
the examination is ordered to diagnose a problem, it typically is covered by insurance, but in the United States, the
average cost for patients not covered by health insurance
is $360.14 The Centers for Medicare & Medicaid Services
has yet to recognize this screening method as providing added value to overall patient outcomes and does
not cover expenses for supplemental testing,11 and most
third-party insurers will not reimburse for an examination until they do. Therefore, even though screening
breast ultrasonography is FDA approved, for many
patients the current cost outweighs the benefits.
Conclusion
As breast density notification becomes commonplace,
this high-risk patient population will become more educated about screening breast ultrasonography. Even though
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
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Warner
data supports the prevelance of breast cancer in this group,
studies show conflicting evidence for improved outcomes
with the use of this technology.2,4 In addition, some data
suggest that mortality rates decline insignificantly with
this supplementary examination.3,4 Until more clinical
studies support screening breast ultrasonography, the use
of this test will remain sporadic and limited.
The choice to employ screening breast ultrasonography in combination with annual mammography begins
with assessing a patient’s personal or family history.1,11,12
Health care providers should encourage patients to maintain monthly breast self-examinations and annual screening mammography with digital breast tomosynthesis if
available. It is important to increase breast density awareness among this high-risk population and to promote
preemptive action if breast abnormalities arise. All of
these elements can effectively aid earlier diagnoses equal
to that of screening breast ultrasonography.3,4,13,15-17
Lisa Warner, BS, R.T.(R)(M), is a certified breast health
navigator for TriStar StoneCrest Medical Center in Smyrna,
Tennesssee.
References
1. Clemow C. Automated breast ultrasound (ABUS): adjunct to
mammography breast cancer screening. MDNEWS Web site.
http://www.mdnews.com/news/2014_11/automated-breast
-ultrasound-(abus)-adjunct-to-mammography-.aspx.
Published November 28, 2014. Accessed January 16, 2015.
2. Berg WA, Zhang Z, Lehrer D, et al. Detection of breast
cancer with addition of annual screening ultrasound or a
single screening MRI to mammography in women with
elevated breast cancer risk. JAMA. 2012;307(13):1394-1404.
doi:10.1001/jama.2012.388.
3. Supplemental ultrasound more costly than effective. Diagnostic Imaging Web site. http://www.diagnosticimaging.com
/breast-imaging/supplemental-ultrasound-more-costly-effec
tive. Published December 17, 2014. Accessed January 19, 2015.
4. Kuehn BM. Breast density and cancer. JAMA. 2012;308(16)
:1621. doi:10.1001/jama.2012.13639.
5. U.S. Food and Drug Administration. Proposed summary of
safety and effectiveness data (§814.44): somo•v automated
breast ultrasound system. http://www.fda.gov/downloads/Advi
soryCommittees/CommitteesMeetingMaterials/Medical
Devices/MedicalDevicesAdvisoryCommittee/Radiological
DevicesPanel/UCM299402.pdf. Accessed January 19, 2015.
6. FDA approves first breast ultrasound imaging system for dense
breast tissue [news release]. Silver Spring, MD. U.S. Food and
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
Drug Administration; September 18, 2012. http://www.fda
.gov/NewsEvents/Newsroom/PressAnnouncements/ucm
319867.htm. Accessed January 21, 2015.
7. GE healthcare announces FDA approval of Invenia
Automated Breast Ultrasound System (ABUS) for enhanced
patient experience and more accurate diagnosis than mammography alone in women with dense breasts [news release].
Milwaukee, WI. PRNewswire; June 3, 2014. http://www
.prnewswire.com/news-releases/ge-healthcare-announces
-fda-approval-of-invenia-automated-breast-ultrasound-system
-abus-for-enhanced-patient-experience-and-more-accurate
-diagnosis-than-mammography-alone-in-women-with-dense
-breasts-261647211.html. Accessed January 21, 2015.
8. What are the risk factors for breast cancer? American Cancer
Society Web site. http://www.cancer.org/cancer/breastcancer
/detailedguide/breast-cancer-risk-factors. Updated August 19,
2015. Accessed January 23, 2015.
9. American College of Radiology. ACR BI-RADS ATLAS—
Mammography: reporting system. http://www.acr.org/~
/media/ACR/Documents/PDF/QualitySafety/Resources
/BIRADS/01%20Mammography/02%20%20BIRADS%20
Mammography%20Reporting.pdf. Published 2013. Accessed
January 16, 2015.
10. Federal legislation to standardize density reporting introduced.
Are you dense? Advocacy Web site. http://www.areyoudensead
vocacy.org/efforts/. Published 2015. Accessed January 27, 2015.
11. Breast cancer screening – for health professionals (PDQ).
National Cancer Institute Web site. http://www.cancer.gov
/cancertopics/pdq/screening/breast/healthprofessional
/page8. Updated February 6, 2015. Accessed January 23, 2015.
12. Brem RF, Lenihan M, Lieberman J, Torrente J. Screening
breast ultrasound: past, present and future. AJR Am J
Roentgenol. 2015;204(2):234-240. doi:10.2214/AJR.13.12072.
13. Hardy, K. Ultrasound screening — establishing its role in
women with dense breast tissue. Radiology Today Web site.
http://www.radiologytoday.net/archive/rt0314p10.shtml.
Published March 2014. Accessed January 27, 2015.
14. Breast ultrasound cost. Costhelper Health Web site. http://
health.costhelper.com/breast-ultrasounds.html. Published
2015. Accessed December 22, 2015.
15. Bolen C. Breast density changes the breast-imaging landscape.
Appl Radiol. 2013:42(3):20-25.
16. Gartlehner G, Thaler K, Chapman A, et al. Mammography in
combination with breast ultrasonography versus mammography for breast cancer screening in women at average risk.
Cochrane Database Syst Rev. 2013;30(4):CD009632.
doi:10.1002/14651858.CD009632.pub2.
17. Azvolinsky A. Digital mammography plus tomosynthesis
improves breast cancer screening. Cancer Network Web site.
http://www.cancernetwork.com/breast-cancer/digital-mam
mography-plus-tomosynthesis-improves-breast-cancer-screen
ing. Publsihed August 6, 2013. Accessed January 27, 2015.
459
Focus on Safety
Occupational Exposure and Adverse Effects
in the Radiologic Interventional Setting
Cannon Walden, BS, R.T.(R)(VI)
P
rofessionals who work in an occupation involving radiological procedures can be at risk for
exceeding annual radiation dose limits and the
resulting long-term adverse health effects it
causes.1-18 However, overexposure to radiation and the
resulting adverse effects might be avoided with proper
radiation protection, increased radiation knowledge, and
adherence to safety practices. The literature supports
this approach, suggesting ways for those most at risk for
radiation-related health illnesses to prevent them.
Radiologists Receive Higher Doses
With the potential for protracted fluoroscopy use during an interventional procedure, all staff in the suite are
at risk for radiation exposure. However, because of the
minimal distance between a physician and the patient,
the physician’s unintended dose is the highest.2,5,7,8 Nurses
are second closest to the source of scatter radiation and
receive the next highest dose, and radiologic technologists receive the third highest unintended dose.2,5,7,8
In a 2013 study, Chida et al acquired the annual
occupational dose for all workers in an interventional
cardiology setting with the use of the effective dose
formula and dose equivalent (see Box).2 Each worker
in the study wore 2 dosimetry badges: one under the
personal lead apron (0.35-mm lead equivalent) at the
chest or waist, and one outside the personal lead apron
at the neck. Dc1.0 was the chest or waist badge dose
under the lead apron at 1-cm dose equivalent, Dn1.0
was the neck badge dose outside the lead apron at 1-cm
460
Box
Effective Dose and Dose Equivalent Formulas2
Effective dose  0.89  Dc1.0  0.11  Dn1.0
Dose equivalent  1.00  Dn0.07
dose equivalent, and Dn0.07 was the neck badge dose
outside the apron at 70 µm dose equivalent.2 The results
showed that physicians received the highest doses, and
technologists received the lowest dose (see Table).2
The International Commission on Radiological
Protection and the National Council on Radiation
Protection and Measurements established a standard
annual occupational exposure limit of 50 mSv per year
for the whole body (stochastic); the groups also set
150 mSv for the lens of the eye and 500 mSv for the
skin, hands, and feet (nonstochastic).2,5-8 The established lifetime effective dose limit—age in years 
10 mSv—is intended to be proportional to the risk of
radiation-induced cancers and associated diseases. A
busy interventional radiologist who takes all appropriate radiation safety precautions is unlikely to reach the
set standards for occupational dose limits.5-8
Radiation-related Health Risks
According to some studies, even radiation dose levels
below established occupational limits can present risk for
adverse health effects.1-18 An increased incidence of cataracts, cancer, and diseases, such as nonmalignant thyroid
nodular disease and parathyroid adenoma, correlate with
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
Focus on Safety
Walden
Table
Annual Occupational Dose in millisieverts per year2
Annual Mean  SD Effective Dose (Range)
Annual Mean  SD Dose Equivalent (Range)
Physicians
3.00  1.50 (0.84-6.17)
19.84  12.45 (7.0-48.5)
Nurses
1.34  0.55 (0.70-2.20)
4.73  0.72 (3.9-6.2)
Radiologic Technologists
0.60  0.48 (0.02-1.43)
1.30  1.00 (0.2-2.7)
Abbreviation: SD, standard deviation.
long-term radiation exposure.8,16 Klein et al reported that
the biological effects of radiation reaffirm the utility of
the linear no-threshold model of radiation risk for solid
cancers. This hypothesis states that any radiation dose
carries with it an associated risk of cancer induction and
that the risk increases with higher doses.8 Radiation dose
for occupational workers, for example, varies depending
on the caseload and length of procedures.
Fluoroscopy-guided diagnostic procedures have
become lengthier and more complex, require the use of
additional radiation, and frequently require the use of
imaging views that are unfavorable for the operator with
regard to occupational exposure. 4,8,16 Unfavorable imaging views result when the fluoroscopy tube angles away
from the typical vertical position and generates scatter
from the patient directing it toward a nearby worker.1
Procedures that might result in high exposure to workers include anything that lasts a substantial amount of
time and encompasses examinations that involve intervention (eg, embolization, thrombolysis, angioplasty).1
Conclusive findings have not been established for
determining radiation-induced cancers, although evidence has been reported in radiation-induced settings.
The U.S. Radiologic Technologist Study, underway
since 1982, is the largest study incorporating medical
professionals who are exposed to ionizing radiation. The
study’s goal is to understand the link between repeated
low-dose radiation exposure and cancer and other health
conditions. Along these lines, Preston et al reviewed cancers in atomic bomb survivors and found that an exposure greater than 1 Sv was associated with an increased
risk of tumors in the brain and central nervous system.8
When radiation protection tools are absent, workers
in the interventional radiology setting are at risk for lens
opacity, otherwise known as cataracts.3,5,14,15 Lens opacities, which cause visual impairment, are classified into
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
3 forms according to their anatomical location: nuclear,
cortical, and posterior subscapular.3 Posterior subscapular, the least common form, is most notably associated
with ionizing radiation exposure.3 Other factors can
cause cataracts, but radiation cataract severity and latency specifically are related to higher radiation dose.3,14,15
Evidence suggests that the current 150 mSv per
year dose limit to the lens of the eye is too high
and the limit is under review by an International
Commission on Radiological Protection task
group. 3,4,8,14,15 Ciraj-Bjelac et al indicated that the
threshold for cataract development is likely lower than
the current guidelines of 2 Gy to 5 Gy, and might be
even less than 0.5 mGy. 3 Radiation-induced cataracts
also might be more accurately described in a linear
fashion and not by a threshold model. 3,14,15 Other evidence suggests that lens opacities occur within a few
years at low doses (dose rates similar to those seen in
the occupational setting) and that visibly disabling
cataracts occur after 25 years or more. 3 Chida et al
cited a study that determined 37% of the 59 interventional radiology physicians who were screened had
small opacities, an early sign of cataracts.19
Causes of Increased Exposure
Continuous direct exposure will result in a worker
exceeding his or her annual radiation dose limits quickly.
Although avoiding all radiation scatter to the hands during some procedures is impossible, physicians should keep
their hands as far from the primary x-ray beam as possible
without negatively affecting the procedure’s outcome.5
Shielding devices for hands are available but lack
sufficient radiation protection. Disposable surgical
gloves incorporate .02 mm of lead and provide a dose
reduction of only 15% to 20%.5 Efstathopoulos et al
conducted research analyzing physicians who wore
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Focus on Safety
Occupational Exposure and Adverse Effects in the Radiologic Interventional Setting
8 thermoluminescent dosimeters next to their eyes,
wrists, fingers, and legs during 25 interventional procedures. The physicians’ left wrists received the highest
radiation dose, although limits were not exceeded.5
Because the annual dose received depends on the number of procedures performed annually, as well as the
length of time required for those procedures, physicians
should keep in mind that poor safety practices can lead
to exceeding annual radiation dose limits.
In addition, workers might exceed radiation dose limits
if they do not practice radiation protection techniques
including wearing lens protection and a lead apron when
stepping into a suite to monitor a procedure.5,9,14,15 Vano
et al presented a 2010 study completed in South America
in which 72% of interventional cardiologists reported
no use of ceiling-suspended protection screens or ocular
radiation protection during the recorded procedures, and
44% reported no use of ceiling screens for previous procedures.15 Studies have shown that the use of a table curtain
can reduce doses to the lower extremities by 64%, whereas
a similar dose reduction at the upper body is achievable by
the use of ceiling-mounted screens.5 For nurses, recorded
doses were low (maximum dose to the extremities 41 Sv
and maximum dose to the eyes 16 Sv) indicating that
their position and the protective shields they used during
intervention effectively reduced irradiation.5 Protection
tools should be used routinely with fluoroscopy so staff
can remain below established exposure limits.
Radiation Protection Recommendations
The greatest source of secondary radiation for occupational workers is scatter radiation. One method for
reducing occupational dose is to follow the as low as
reasonably achievable (ALARA) principle when imaging patients.1 Other ways are to reduce the amount of
radiation time, increase the distance from the source
when possible, and use lead-equivalent protection.
These practices greatly reduce dose to both the patient
and the worker.
Educating workers about radiation safety is essential
for ensuring overall safe practice in the interventional
setting. Niklason et al reported that 20% to 30% of
cardiologists did not use their dosimeters routinely.15
This failure interferes with radiation dose recordings
and results in inaccurate rates of exposure to workers.
462
Workers have the right to know their dose, and they
need to keep track of the exposures they have received.
Dose reports should be posted for employee review.
Wearing dosimeters correctly and at all times when
using fluoroscopy is the only way dose-received data
will be accurate. The monitoring device should be worn
outside of clothing on the anterior surface of the body,
between chest and waist level.1 When a lead apron is
worn, the dosimeter should be worn outside the apron
at collar level (see Figure).1 Other ways to reduce overall dose include5,6,18:
 Minimizing the use of fluoroscopy.
 Using collimation.
 Using appropriate positioning techniques.
 Using available patient dose reduction technology.
 Minimizing the number of acquired images.
 Using quality-assured radiation equipment.
Training programs that include initial training and regular retraining for all involved staff should be available
at imaging facilities. To ensure safe operating practices,
all staff members should be certified in their area and be
knowledgeable about procedures and radiation use.
Shielding
Generally, 3 types of shielding are used: structural
shielding, equipment-mounted shields, and personal
protective devices.4-6,18 Structural shielding is built into
the ceiling, floor, walls, windows, and doors of the
interventional suite and protects anyone outside the
room because the scatter radiation is contained in the
procedure space. Equipment-mounted shielding includes
protective drapes suspended from the fluoroscopy tube
or procedure table that generally contain 0.25-mm lead
equivalency.1 The table-suspended drapes reduce operator dose substantially but lose their effect when a steep
oblique or lateral projection is required.1,4-6,18
Personal protective devices include lead equivalent
aprons, thyroid shields, eyewear, and gloves. The principle radiation protective device is the wraparound leadequivalent apron with attached thyroid shield.1 Properly
fitted aprons provide adequate radiation protection and
reduce ergonomic hazards to the individual.4-6,18 Protective
aprons are to be worn at all times when fluoroscopy is used
and are required to possess a minimum of 0.5-mm lead
equivalent if the peak energy of the x-ray beam is 100 kV.1
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
Focus on Safety
Walden
TLD badge
Figure. A thermoluminescence dosimeter (TLD) badge should be
worn outside of clothing on the anterior surface of the body, between
the chest and waist level. When a lead apron is worn, the dosimeter
should be worn outside the apron at the collar level.
Some interventional suites have rolling and
stationary shields made of lead-equivalent plastic. These, along with ceiling-suspended shields,
should be used for procedures of significant length.
Lightweight, sterile, disposable shields that protect
the operator from scatter radiation also are available. This type of shielding device lies directly on the
patient, just outside the primary x-ray beam. Simons
et al conducted a study in which 40 interventional
radiology procedures were performed, 20 with and 20
without sterile, disposable, radiation absorbing surgical drapes containing x-ray attenuation material. The
results showed an 80% reduction in radiation dose
(0.09 Sv/s with shielding vs 0.47 Sv/s without
shielding, P  .05) to the physician performing the
procedures when the drapes were used.12 This study
demonstrated that a sterile, disposable, radiationabsorbing drape provides a practical means of augmenting conventional radiation shielding.12
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
Improved Technology
Advances in technology have helped to reduce radiation dose. Today, there are a variety of built-in and
manual features available on equipment that reduce
the radiation dose to the patient and to surrounding
workers. A majority of fluoroscopy equipment comes
with settings such as low dose-rate mode, low pulse-rate
option, low dose-per-frame settings for image acquisition, and low frame-rate options for image acquisition. 4
These user selection options reduce patient dose and
reduce scatter to workers. Advances in image processing
technology compensate for a majority of reduced image
quality and reduced radiation to workers. In addition,
built-in equipment configurations involve spectral
beam filtration and the use of increased x-ray beam
energy, which also reduces radiation to workers. 4 The
fluoroscopy operator (whether this is the radiologist
or technologist) might consider consulting a qualified
medical physicist to gain complete understanding of the
operator modes available and other equipment features.
Conclusion
Interventional radiologic procedures carry the risk
of causing adverse health effects in workers because
of the continuous exposure they receive from ionizing
radiation. The most concerning adverse effect of radiation exposure to workers is to the lens of the eye, and
this exposure is most likely to affect the interventional
radiologist or cardiologist because of his or her proximity to the radiation source. However, radiologic science
professionals and clinicians can protect themselves and
minimize health risks associated with radiation exposure by wearing appropriate radiation protection and
following the ALARA principle.
Cannon Walden, BS, R.T.(R)(VI), is a special
procedures technologist for Wake Forest Baptist Medical
Center in Winston-Salem, North Carolina.
References
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2013;200(1):138-141. doi:10.2214/AJR.11.8455.
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Focus on Safety
Occupational Exposure and Adverse Effects in the Radiologic Interventional Setting
3. Ciraj‐Bjelac O, Rehani MM, Sim KH, Liew HB, Vañó E,
Kleiman NJ. Risk for radiation‐induced cataract for staff
in interventional cardiology: is there reason for concern?
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9. Papierz S, Kamiński Z, Adamowicz M, Zmyślony M.
Assessment of individual dose equivalents Hp(0.07) of medical staff occupationally exposed to ionizing radiation in 2012.
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10. Servomaa A, Karppinen J. The dose-area product and assessment of the occupational dose in interventional radiology.
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11. Siiskonen T, Tapiovaara M, Kosunen A, Lehtinen M,
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13. Vañó E, Gonzalez L, Fernandez J, Alfonso F, Macaya C.
Occupational radiation doses in interventional cardiology:
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14. Vañó E, Gonzalez L, Fernández JM, Haskal ZJ. Eye lens
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15. Vañó E, Kleiman NJ, Duran A, Rehani MM, Echeverri D,
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Radiation exposure to medical staff in interventional and
cardiac radiology. Br J Radiol. 1998;71(849):954-960.
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19. Haskal ZJ, Worgul BV. Interventional radiology carries
occupational risk for cataracts. RSNA News. 2004;14:5-6.
Cited by: Chida K, Kaga Y, Haga Y, et al. Occupational dose
in interventional radiology procedures. AJR Am J Roentgenol.
2013;200(1):138-141. doi:10.2214/AJR.11.8455.
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
Teaching Techniques
Just-in-Time Teaching
Kevin R Clark, EdD, R.T.(R)
J
ust-in-Time Teaching (JiTT) is an instructional
strategy that combines online study assignments
with interactive classroom environments to
improve student learning and understanding.1-3
Before class, students answer a small set of Web-based
questions involving upcoming course materials and submit their responses online via a learning management system (LMS).1-2 These questions are referred to as JiTT exercises.1-3 Once submitted, the instructor reviews the students’ responses and develops in-class activities that target
learning gaps or areas of confusion.1-2 Connecting out-ofclass and in-class learning allows the instructor to read the
students’ submission “just in time” to adjust the upcoming
classroom lesson to address misconceptions, faulty or
incomplete reasoning, and potential knowledge gaps.1-3
Consider the following exercise authored by
Kathleen Marrs, PhD, professor of biology for Indiana
University-Purdue University Indianapolis:
Allison is driving her parents when they get in a serious
car accident. At the emergency room, the doctor tells
Allison her mother is fine, but her father, Bob, has lost
a lot of blood and will need a blood transfusion. Allison
volunteers to donate blood. The doctor informs Allison
her blood type is AB, and Bob is type O.3
This scenario, used to prepare introductory biology students for an upcoming lesson on genetics, was posted
within the LMS, and students were required to answer
the following questions3:
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
 Can Allison donate blood to Bob? Why or why not?
 Allison, who is a biology student, begins to wonder
if she is adopted. What would you tell her and why?
Marrs reviewed the students’ responses and adjusted
the upcoming lesson based on what those responses
revealed.
Implementation
Because of its flexibility, this strategy can be applied
to a variety of content, courses, curriculum, and disciplines.2 It can be combined with other innovative, studentcentered teaching practices including flipped classrooms,
cooperative learning strategies, peer instruction practices,
and interactive lecture demonstrations.2 Before implementing the JiTT strategy, the instructor must consider
his or her own teaching style, classroom setting, and use
of technology.1-2 The instructor must decide which courses will use the strategy, how often to assign the exercises,
which technology tools will be used, and what activities
and teaching methods will be used to conduct the lesson.
Before implementing the JiTT strategy, the instructor must first develop effective questions the students
will answer before class.1-3 These questions should
require students to apply new concepts or ideas in ways
that cannot simply be looked up in a textbook. They
should be relatively brief, requiring 15 to 30 minutes to
complete.2 Ultimately, the questions should focus on
the key ideas planned for the upcoming class and align
with learning goals and objectives.1-3
465
Teaching Techniques
Just-in-Time Teaching
Once the instructor develops the questions, he
or she posts them on the LMS for the students.
Instructors should set the due dates for students’
responses to allow themselves enough time for review
and assessment.2 The due date is dependent on the
complexity of the questions, how many students are
in the class, and how quickly the instructor can review
and process the responses. In addition, the instructor should consider whether students are allowed to
view other students’ responses before posting their
response. Most LMSs have features that require students to post before viewing other responses. When
reviewing the responses, the instructor should look
for misconceptions and other gaps in understanding.2 While reviewing, it is common to find clusters of
responses that highlight similar learning challenges.2
These challenges help the instructor develop activities
for the upcoming class that address the students’ misunderstandings.
The final step with the JiTT strategy is implementing the in-class, follow-up activities.2-3 These activities
can be as simple as displaying anonymous student
responses and conducting a discussion asking students
to point out incomplete or incorrect thought processes,
expand on the submitted responses, or even extend
the highlighted concept.2 This can be achieved by
displaying 2 contrasting answers and asking students
to analyze them. This exercise can sharpen learning
and communication skills as students support and
defend their responses. More importantly, this strategy
is most effective when students’ responses are used to
develop interactive, collaborative activities that target
those learning gaps.2 Depending on the content, those
in-class activities could include problem-based learning and role-playing scenarios. Specifically, hands-on,
interactive, collaborative activities that address the
challenges and areas of confusion work best.2
Radiography Curriculum Examples
The JiTT strategy can be used in a variety of courses
within a radiography curriculum. In a basic positioning
course, students can be presented with a trauma scenario
in which the emergency department doctor orders a variety of complex examinations. Students then can submit
their responses within the LMS detailing the order to
466
perform the examinations and justifying their choices.
After reviewing the students’ responses, the instructor
can lead a class discussion on the correct order. Then,
the instructor can add examinations and let the students
work together to see where the new examinations best
fit. In an advanced radiographic procedures course, the
instructor can present a scenario in which the radiologist
cannot clearly visualize the hepatic flexure during a barium enema examination and requests an additional view
to better demonstrate the anatomy. The students must
decide which oblique to perform, how much to angle the
patient, and whether to perform the examination with the
patient in the prone or supine position.
Multiple scenarios involving imaging can be used
with the JiTT strategy. The instructor can upload a
grainy or dark image to the LMS and ask the students
how they would improve the quality of the image given
the original technique. Before submitting a response in
the LMS, the students would have to decide whether
to change kVp, mAs, or both; show how much they
would adjust the exposure factors; and explain why they
selected the new technique. After reviewing the students’ responses, the instructor can have the students
make the exposures using their new techniques in the
laboratory setting and view the resulting image.
Another exercise can involve determining why a
supine abdominal image using the table Bucky resulted
with grid lines. The students can respond by speculating what caused the grid lines and stating how to correct it. After reviewing the responses, the instructor can
use lab time to allow students to test their theories by
making various exposures and adjustments. A group
discussion can follow.
Other JiTT exercises that can be implemented easily
in other radiography courses include:
■ Health law – describe ethical issues.
■ Patient care – detail vital signs with critical
patients.
■ Physics – describe x-ray production within the
tube.
Current Research
One study assessed the acceptability of the JiTT
strategy compared with traditional lecture teaching
among medical students. 4 The students completed a
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
Teaching Techniques
Clark
questionnaire after being taught traditionally and via
the JiTT approach. The students perceived the JiTT
strategy as superior to traditional teaching with statistically significant outcomes. 4 Students indicated that this
strategy was less monotonous and increased their alertness during class when compared with a traditional lecture course.4 The researchers identified the JiTT strategy as more interactive, shifting the nature of teaching
to a student-centered approach.
Another study involving 94 higher education
students also acknowledged the increase in interaction when using the JiTT strategy; however, several
potential problem areas also were identified.5 Students
struggled with the exercises and expressed difficulties answering questions they did not completely
understand even after reading the required textbook
assignments. Some students described the exercises as
daunting and not very useful. Many students preferred
hearing the instructor lecture rather than listening to
student contributions during class. Another problem
area noted in this study was the lack of attendance. Low
attendance undermined the JiTT strategy.5
Comparison With Flipped Classrooms
Initially, it might appear that the JiTT strategy is similar to the flipped classroom; however, with a flipped classroom students engage in interactive lessons and activities
during class that reinforce new concepts introduced
before class.6 With the JiTT strategy, only areas of misconception, faulty or incomplete reasoning, and potential
knowledge gaps are addressed.1-3 Several instructors have
begun to use a combination of the JiTT strategy and the
flipped classroom called the Flip-JiTT, in which content is
introduced to students before class via Web-based media,
and students actively participate in an in-class activity
based on that content.6 Depending on the level of difficulty, the content might be reinforced by the in-class
activity, as in the flipped classroom, or the instructor
might address only the identified areas of weakness with
an interactive activity, which is the JiTT strategy.
for class; therefore, this strategy can enhance student
engagement and improve student learning. Despite the
simplicity of its structure, when implemented effectively, the JiTT strategy provides valuable feedback on
student learning processes to help instructors develop
in-class activities and use class time more productively. Kevin R Clark, EdD, R.T.(R), is assistant professor and
graduate faculty in the Department of Radiologic Sciences
for Midwestern State University, in Wichita Falls, Texas. He
can be reached at [email protected].
References
1. Novak G. Just-in-Time Teaching. Just-in-Time Teaching Web
site. http://jittdl.physics.iupui.edu/jitt/what.html. Accessed
September 30, 2015.
2. Just-in-Time Teaching (JiTT). Starting Point Web site.
http://serc.carleton.edu/introgeo/justintime/index.html.
Accessed September 30, 2015.
3. Novak G. Just-in-Time Teaching: an interactive engagement
pedagogy. Edutopia Web site. http://www.edutopia.org/blog
/just-in-time-teaching-gregor-novak. Published March 6,
2014. Accessed September 30, 2015.
4. De S, Kavitha N, Kanagasabai S. Acceptability of Just-in-Time
Teaching amongst medical students: a pilot study. Educ Med J.
2014;6(1):11-19. doi:10.5959/eimj.v6i1.186.
5. Wanner T. Enhancing student engagement and active
learning through Just-in-Time Teaching and the use of
PowerPoint. Int J Teach Learn High Educ. 2015;27(1):154-163.
6. Lasry N, Dugdale M, Charles E. Just in time to flip your classroom. http://arxiv.org/ftp/arxiv/papers/1309/1309.0852.pdf.
Accessed September 30, 2015.
Conclusion
Because of its flexibility, the JiTT strategy can be
implemented easily in the radiologic science curriculum. Students are required to improve their preparation
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
467
Writing & Research
Writing With Style
Richard J Merschen, EdS, R.T.(R)(CV), RCIS
Bruce W Long, MS, R.T.(R)(CV), FASRT, FAEIRS
W
hen writing a scholarly article for a journal,
many prospective authors want to know
why the writing style is so important and
why many radiologic science journals use
the AMA Manual of Style rather than another style
guide with which they might be familiar.
All professional writing styles provide important
advantages. They have specific rules for content, structure, style, and substance that mark manuscripts as professional high-quality, scholarly work with a consistent
format (see Box 1).1,2
Several style manuals are available and each is
developed to best present the material related to a
profession or area of study. For example, the Modern
Language Association (MLA) style is used for publication in the humanities, 3 whereas the American
Psychological Association (APA) style was developed
for publication in the behavioral sciences. 2 Life sciences publications commonly use the Council of Science
Editors (CSE) style 4 or American Medical Association
(AMA) style. All writing styles offer significant
advantages for authors and their audience.
When a journal publishes dozens of articles per year, a
professional writing style is advantageous for the authors,
audience, reviewers, and other vested parties. A writing
style allows authors and readers to focus on the content
of an article because it guides consistent formatting to
create an organized and professional presentation. This
consistency makes it easier for professionals to read the
468
article and efficiently glean the critical data presented.
Consistent formatting also helps readers grasp the central
theme and purpose of an article and allows them to find
the reference materials used.
AMA writing style in particular promotes an exceptional level of scholarship and professionalism for the
highly specialized field of the radiologic sciences. AMA
writing style has a track record of use in the medical
field and is recognized as a format that promotes highcaliber scholarship. It is used in all of the primary publications in the radiologic sciences including Radiologic
Technology.
Key AMA Style Components
AMA writing style provides a standard for professional, quality articles. A peer-reviewed article that
follows AMA style should include a title, abstract, body
text, references, and supporting materials. The title
should directly align with the substance of the article.
It should state the central idea of the paper, stimulate
an interest for readers, and convey a concise point. The
abstract summarizes the main points of the article in a
well-developed paragraph and usually is followed by a
list of keywords.
The abstract and keywords provide distinct advantages for professionals conducting research and are
important elements in professional publications. An
abstract is a condensed version of the article that
researchers read to determine whether the article will
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
Writing & Research
Merschen, Long
Box 1
Elements of a Well-Styled Paper
1,2
Concise and Clear
Get to the point of an article in as few words as possible. Be
selective when choosing words and phrases, and use words
that are easy to understand. Avoid vagueness and generalities
and concentrate on the theme of the text. In the radiologic
sciences, use terms accepted universally in the profession.
Clearly explain uncommon terms and highlight them in the
abstract.
Error-free
Proper sentence structure, correct spelling, and appropriate
word selection are essential for professional writing. Use short
sentences and easily understood words to reduce errors. Most
computers have software that checks spelling and sentence
structure to minimize errors.
Readable
The theme and purpose of the article should be easy to
understand. The article should have smooth transitions
between concepts, and it should be organized logically. Even if
some terms are new to the reader, a well-written article should
be informative and enjoyable to read. When drafting a scholarly article, ask peers to read and critique it; they are excellent
resources to help determine whether an article is readable.
Avoids Plagiarism
Ensure all sources are referenced properly. Use quotation
marks for direct quotes, and ensure that paraphrased
sections also are referenced. Do not rely on a single source
for an entire article. An article should use high-quality, peerreviewed sources but also should contribute original knowledge to the profession.
Organized
An article should have a well-defined structure including a
title, abstract, body, and reference list. Smooth transitional
sentences should connect paragraphs. New sections in an
article should be identified with proper headings. If possible,
the article also should include visual aids that support the text.
Uses Scholarly References
Scholarly references include articles from medical journals,
publications from professional organizations, such as the
American Society of Radiologic Technologists, and government Web sites. References also should contain the most
current information available, except when providing historical
context to a subject.
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
benefit the specific investigation they are conducting.
A researcher might have to pore over dozens of articles
to find material for research, and a well-constructed
abstract is highly valued by professional readers and
researchers. The abstract allows readers to immediately
identify key concepts covered in an article. Creating
an abstract can be demanding because it must be brief;
however, when authors become accustomed to developing robust abstracts, they improve the quality and professional image of their work.
The use of keywords, which is unique to AMA style,
allows readers to quickly see words that are central to
understanding the article and that might not be familiar
to them before reading an article. Keywords improve the
readability of the article by letting readers know important terms and phrases that need to be understood when
reading the article. In addition, these keywords are the
basis for searches of electronic article databases.
The body text should be well organized and fully
present all the key points introduced in the abstract.
Articles should have proper headings, fluid transitional
sentences, and error-free writing. Scientific papers, for
example, should contain introduction, methods, results,
and discussion sections, which also is known as the
IMRAD format. 4,5 Research should be supported with
images, graphs, tables, charts, and other visual elements
that add value to the article.
AMA style specifically places tables, charts, graphs,
images, and other visual aids in the text of the article.3 In
contrast, APA style places all appendices at the end of the
text.2 In medical writing, these visual aids help readers
interpret the article. Graphs, charts, and tables are data
rich, condense large amounts of material, clarify and summarize complex concepts, and organize key data into a
crisp, tightly worded format. In the radiologic sciences,
including medical images enhances an article’s quality
and readability.
All writing styles include a format for citing references within the text. AMA style requires the use of superscript numbers to cite reference articles in the body
text.1 Each reference is given a number corresponding
to the order that it was first cited in the text. This citation style saves valuable space in an article while allowing readers to easily find the associated references at the
end of the article. This economy of space is extremely
469
Writing & Research
Writing With Style
important when an article might be restricted to 1000
to 3000 words. In contrast, the APA format requires
that the name of the author, as well as the year and
pages cited, be included within parentheses for each
citation throughout the article.2 All of this consumes
space, and a large number of references can consume
50 or more words in an article. Most importantly, using
superscript numbers to indicate references produces a
cleaner, easier-to-read article (see Box 2).
The final, essential element of citation is a highquality reference list that demonstrates peer-reviewed
research methods to support the text. The reference
list appears at the end of the article, and the first reference used in the text will have the number 1 next to it.
The next reference cited will be indicated by the number 2, and each subsequent reference will be numbered
sequentially. AMA style follows the suggested format
developed for uniformity by the U.S. National Library
of Medicine and helps authors to remain consistent in
their citations.1
Additional Benefits of Style
Besides creating an organized and professionally formatted article, professional writing styles help authors
avoid plagiarism by providing a detailed format for citation. Plagiarism is a serious issue in professional writing,
and it is important to avoid because it deprives original
authors of recognition for their work. When original
authors are not cited, readers cannot find articles the
author used to collect additional data that might be essential for their own research.1,2 Most importantly, plagiarism
is intellectual theft, unprofessional, and tarnishes the
image of the author and the publication to which it is submitted. Because professional writing styles have rigorous
methods for referencing material, they minimize the possibility of plagiarism. Although citation rules might seem
Box 2
Example of American Medical Association
In-text Citation Style6
Some recommend development of a comprehensive marketing plan.1,2 However, others recommend conducting a needs
assessment first.3-8 Meyers has performed significant research
in the area.4,6,9-12 He found that an adequate needs assessment
can prevent improper allocation of resources.12
470
tedious and mundane, they are designed to help authors
avoid plagiarism, give proper credit to previous authors,
and aid further research.
Another advantage of using professional writing
styles is for the professional reviewers who read dozens of
articles each year, and who need to focus on the content
of the article. A consistent, organized structure with logical headings and subheadings allows reviewers to read
and review articles more quickly. When the title, abstract,
body text, references, and supporting materials are organized and formatted consistently, this task becomes easier.
The finished product looks professional and the content
can be critiqued efficiently.
In addition, the 10th edition of the AMA Manual of
Style has an excellent section focusing on medical ethics
and conflicts of interest. Although all life-sciences style
guides include information about these issues to some
extent, the AMA style guide has placed strong emphasis on these topics so researchers can avoid conflicts of
interest and ethical lapses in their professional writing.1
Medical writing is designed to protect human subjects
and scientific inquiry and avoid conflicts of interest.
This is a particular strength of the AMA writing style,
and the 10th edition is the gold standard for addressing
these critical issues in medical publishing.
Conclusion
All professional writing styles provide a system for
creating a quality manuscript; the American Society of
Radiologic Technologists (ASRT), in particular, has chosen AMA style because of its many advantages. Authors
used to writing in another style should not be deterred
from publishing an article requiring the use of AMA style.
The ASRT provides helpful resources to guide authors
through the writing process in its online author guide. In
addition, continuing education materials that further prepare prospective authors are available from the ASRT.
The ASRT editorial staff wants medical imaging professionals to be successful authors and encourages readers
to contribute to the journals by sharing clinical and professional insights with their peers. They welcome submissions of original research, case studies, literature reviews,
and manuscripts for a variety of column types that offer
radiologic technologists’ perspectives on a variety of
issues.
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
Writing & Research
Merschen, Long
To learn more about writing professionally, visit the
ASRT author guide at asrt.org/authorguide.
Richard J Merschen, EdS, R.T.(R)(CV), RCIS, is senior
staff technologist for the cardiac catheterization and cardiac
electrophysiology laboratories at Pennsylvania Hospital and
adjunct professor for Thomas Jefferson College of Health
Professions in Philadelphia, Pennsylvania. He also serves on
the Radiologic Technology Editorial Review Board. He
may be reached at [email protected].
Bruce W Long, MS, R.T.(R)(CV), FASRT, FAEIRS,
is director and associate professor for the radiologic and
imaging sciences programs at Indiana University School of
Medicine in Indianapolis, Indiana.
References
1. Iverson C, Christiansen S, Flanagin A, et al, eds. AMA
Manual of Style: A Guide for Authors and Editors. 10th ed. New
York, NY: Oxford University Press; 2007.
2. American Psychological Association. The Publication Manual
of the American Psychological Association. 6th ed. Washington,
DC: American Psychological Association; 2011.
3. Modern Language Association. MLA Style Manual and
Guide to Scholarly Publishing. 3rd ed. New York, NY: Modern
Language Association of America; 2008.
4. Council of Science Editors. Scientific Style and Format: The
CSE Manual for Authors, Editors, and Publishers. 8th ed.
Chicago, IL: University of Chicago Press; 2014.
5. Matthews JR, Matthews RW. Successful Scientific Writing: A
Step-by-Step Guide for the Biological and Medical Sciences. 3rd
ed. Cambridge, UK: Cambridge University Press; 2007.
6. Citing your references. American Society of Radiologic
Technologists Web site. http://www.asrt.org/main/news
-research/asrt-journals-magazines/authorguide/resources
/citing-your-references. Accessed January 14, 2016.
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
471
My Perspective
Expect the Unexpected
Mariela Constantino Mazariegos, R.T.(R)
D
eciding what career to pursue is an important
decision. When I decided to register for a radiography program, I couldn’t imagine the work and
dedication involved in achieving this degree—a
degree that offers me the opportunity to be part of a team,
build my confidence, and finish something important. In
the classroom, I learned by reading the textbook, completing anatomy illustrations, and taking notes from lectures.
However, the clinical setting is where all that information
came together as I performed radiographic examinations
on actual patients.
Every day I wondered what new and exciting experience the day would bring. Going to the clinical setting
gave me courage, enthusiasm, and hope knowing that
my goals would be accomplished by having hands-on,
real-life experience to add to lessons learned in the
classroom. The laboratory is the first step in learning,
and it provides an understanding of what to expect
when assisting patients in the workplace. Even though
time in the laboratory is an important part of the
course, students do not get the same type of practice or
patient interaction there as they do in the clinic, and I
learned that performing a skull series is one example in
which theory and practice are not equal.
When I began my clinical rotation, I had little experience with positioning the skull or facial bones. My
clinical sites were not trauma centers, and on the one
occasion I had seen the procedure, a patient was having
a bone survey examination and had no visible fracture or
noticeable disease. The technologist performed a series
472
of radiographs to detect fractures, tumors, or other conditions that might have caused the patient’s health problems.
The series included several images of upper and lower
extremities; the cervical, thoracic, and lumbar spine; ribs;
chest; and skull. I completed some of the images under the
technologist’s supervision, but the technologist performed
the basic projections of the skull including anteroposterior
(AP) and lateral views.
The technologist carried out the examination without using sponges or restriction devices to maintain the
patient’s posture. He made sure the patient’s head was
not rotated or tilted by going to the head of the radiographic table and checking the facial landmarks. To
include the entire skull in the AP projection, the central
ray was directed perpendicular to the nasion (the point
at the nose between the eyes). For the second image, the
patient lay prone and rotated his head laterally with the
right side of his face in contact with the table. The central ray for this projection was directed perpendicular
and above the ear to include the front and back of the
skull. While both images were acquired, the patient was
asked not to breathe and to tuck his chin. The technologist inserted the image receptor, used a grid to improve
the image quality, and used a source-to-image receptor
distance of 40 inches. The images were determined to
be of diagnostic quality, and the patient was discharged
from the department. That experience taught me that
the skull series consists of multiple projections, positions, and central ray angulations to capture the anatomy of interest.
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
My Perspective
Mazariegos
Figure. Phantom skull
positioned with sponges.
Images courtesy of Ann
Verschuuren, MEd,
R.T.(R)(M).
Using a Phantom Skull in the Laboratory
Phantoms allow students to obtain images, make corrections, and improve images without exposing patients
to radiation. The instructor labeled landmarks to provide
students with a guideline for positioning. During a laboratory course before my clinical rotation, I used the phantom skull for the first time, and the experience was not
what I expected. The phantom enabled me to learn more
about the anatomy by seeing through it, and it meant I
could take several radiographs, examine them, and reposition if necessary; however, it was not as easy to position the phantom as I thought it would be. Because the
phantom has no body attached to it, having to use several
sponges or supports makes the positioning more difficult
and time consuming (see Figure). Even when following
the instructions in the textbook regarding the central ray
angulations, some students did not always obtain all the
anatomy of interest.
A patient who is capable of cooperating and comprehending instructions can maintain proper posture during
a procedure, allowing the technologist to obtain better
images. Technologists also should consider the different
types of skull morphologies because the patient’s type will
determine the central ray angulations. Skull shapes are
divided into 3 groups1:
■ Mesocephalic – medium length and breadth.
■ Brachycephalic – short from front to back and
broad from side to side.
■ Dolichocephalic – long from front to back and
narrow from side to side.
A patient’s body habitus will determine where sponges
are required to obtain lines and planes of the skull parallel or perpendicular to the image receptor.
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
The skull, facial bones, and sinuses chapters in
Merrill’s Atlas of Radiographic Positioning and Procedures
offer straightforward and simple instructions, and some
of the positions are similar. However, the actual process
of performing the examination is more complicated
than it seems. Until I was required to do a skull series,
my performance and improvement were based on repetition, but in this case, I did not have the opportunity
to develop a consistent routine to perform the examinations without error. With practice, students gain expertise, but it can take a long time because of the limited
number of examinations they perform.
Today, computed tomography and magnetic resonance imaging are more frequently used than radiography for skull and facial imaging, so it is less likely I will
have the opportunity to perform the skull and facial
views I learned. Even so, I am pleased I chose this gratifying career in which the fundamental practices are the
same, but the variety of situations, patients, and hospital settings are a constant challenge. Some situations
require that I “think outside the box” to obtain a good
image, and I am confident that many more exciting circumstances will arise to challenge me.
Mariela Constantino Mazariegos, R.T.(R), lives in
Riverdale, New Jersey.
Reference
1. Frank ED, Long BW, Smith BJ. Skull. In: Merrill’s Atlas of
Radiographic Positioning and Procedures. 12th ed. St Louis,
MO: Elsevier Mosby; 2012:287.
473
Technical Query
Increased Filtration and
Image Receptor Exposure
Thomas G Sandridge, MS, MEd, R.T.(R)
T
he goal in radiography is to obtain diagnosticquality images with the lowest possible radiation dose to patients. Multiple factors contribute to patient exposure, including total beam
filtration. Beam filtration reduces patient exposure by
attenuating a number of lower-frequency photons
emerging from the tube. Removal of the lower-energy
photons is important, as they would otherwise be
absorbed by the patient’s superficial tissues, contributing nothing to image formation.1
The National Council on Radiation Protection recommends a total beam filtration of 2.5 mm aluminum
equivalence for generators capable of operating above
70 kVp.2 Total filtration is a combination of inherent
and added filtration. Inherent filtration consists of
objects within the tube and tube housing, specifically
the glass of the x-ray tube and the oil surrounding
it. Although not filters, per se, these objects provide
approximately 0.5 mm aluminum equivalence of filtration to the beam as it passes through.2,3 There are 2
sources of added filtration: a thin piece of aluminum
inserted into the path of the beam and the collimator
mirror that reflects light corresponding to the exposure
field. Added filtration for a diagnostic x-ray machine
is approximately 2.0 mm of aluminum equivalence,2,3
resulting in a total beam filtration of 2.5 mm aluminum
equivalence.
In addition to reducing patient exposure, filtration
enhances beam quality and decreases beam quantity
474
by attenuating weaker photons, resulting in an increase
in the beam’s average energy.2,3 Technique charts and
preprogrammed generator settings are based on a total
beam filtration of 2.5 mm aluminum equivalence.
Case Summary
A 28-year-old male presented to the outpatient department for a wrist radiograph. A routine wrist series was performed using a Carestream 7500 unit (Carestream Health
Inc). Although the technologist used the preprogrammed
settings, the resulting exposure index was extremely low.
The images demonstrated some quantum mottle, which
reduces image quality (see Figure 1). The technologist
inadvertently pressed the button for increasing beam
filtration located on the collimator without increasing
technique to compensate. This accounted for the low
exposure index. A rubber cap usually is placed over the
additional filtration button on all collimators at the facility
to prevent this error. The rubber cap was missing when
the exposure was made. The control panel displays filtration options (see Figure 2). Figure 3 is a wrist radiograph
performed on another patient without selecting additional
filtration, resulting in an exposure index within the appropriate range.
Increasing total beam filtration by adding copper or
additional aluminum filters might reduce entrance skin
exposure by as much as 50%; however, an increase in
tube output is required to compensate for the decrease
in beam quantity. 4 To avoid inadequate image receptor
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
Technical Query
Sandridge
A
A
45
45
40
45
40
30
35
25
30
20
15 25
10 20
0
0
40
35
15
5
10
35
25
30
20
25
20
15
10
15
5
B
45
40
30
35
10
45
30
35
25
30
20
15 25
10 20
0
0
15
5
10
5
0
5
0
5
0
40
35
40
0
45
40
45
5
5
35
45
40
30
35
25
30
20
25
20
15
10
15
10
C
B
Figure 2. A. Collimator showing the light button and button for
increasing filtration (arrow). B. Collimator showing rubber cap
mounted over the filtration button to prevent inadvertent pressing.
C. Control panel showing the amount of filtration. When “None” is
selected, the beam has 2.5 mm aluminum equivalence of filtration.
Additional filtration options are below the filter button. Images
courtesy of the author.
Figure 1. A. Posteroanterior (PA) wrist radiograph exposed with
55 kVp and 2 mAs, an appropriate technique for this department.
The exposure index number was 1061 but should be at least 1600.
B. The magnified image demonstrates quantum mottle resulting
from image receptor underexposure. Images courtesy of the author.
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
exposure, technologists should verify the filtration
amount indicated on the control panel before exposing.
Doing so will reduce the need for repeat exposures due
to inadequate image receptor exposure.
475
Technical Query
Increased Filtration and Image Receptor Exposure
Figure 3. PA wrist radiograph of a different patient exposed with
55 kVp and 2 mAs, resulting in an exposure index number of 1743.
Image courtesy of the author.
Thomas G Sandridge, MS, MEd, R.T.(R), is a regular
contributor to Radiologic Technology’s Technical
Query column and is program director for the School of
Radiography at Northwestern Memorial Hospital in
Chicago, Illinois.
References
1. Bushong SC. X-ray production. In: Radiologic Science for
Technologists: Physics, Biology, and Protection. 10th ed. St
Louis, MO: Elsevier Mosby; 2013:123-135.
2. Carlton RR, Adler AM. Filtration. In: Principles of
Radiographic Imaging: An Art and a Science. 5th ed. Clifton
Park, NY: Delmar, Cengage Learning; 2015:170-177.
3. Bushong SC. X-ray emmission. In: Radiologic Science for
Technologists: Physics, Biology, and Protection. 10th ed. St
Louis, MO: Elsevier Mosby; 2013:136-146.
4. Martin C. Optimisation in general radiography. Biomed
Imaging Interv J. 2007;3(2):e18. doi:10.2349/biij.3.2.e18.
476
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
Open Forum
In the Interest of Clarity
DBT Reimbursement
In the Directed Reading “Digital Breast Imaging
Workflow,” published in Radiologic Technology (Vol.
87, No. 3), the author states, “Technologists must be
sure to document that the DBT was done in conjunction with a conventional digital mammogram and
radiologists must include that in the report.” The
author cites an article by Carin Carlson published on
AuntMinnie.com titled “How to Maximize Your Breast
Imaging Reimbursement.” Carlson’s article does not
state the technologist should document this information. I have also researched this online with Medicare
and haven’t found that this needs to be documented by
the technologist. The radiologist needs to dictate it in
the patient’s report.
It is my understanding that technologists are
included in the phrase “their staff,” and that technologists document technical factors, positions, and examinations as part of the imaging process (eg, RIS, EHR).
I was not suggesting that technologists fill out reports
or billing paperwork, only that their documentation
supports the record of the study and report.
Teresa Odle, BA, ELS
Ruidoso Downs, New Mexico
Artful Insight
The author responds:
Carlson did not precisely say the technologist
should document, but that “Without the proper documentation, radiologists will lose this added revenue
from Medicare for breast ultrasound and DBT services. Radiology practices should ensure that their
staff and outsourced billing vendors are current on
these issues in order to maximize reimbursements
today and into the future.”
This letter is in response to an article by Mark
Hom, MD, titled “The Art and Science of Light: An
Illustrated Retrospective” that appeared in Radiologic
Technology (Vol. 86, No. 6).
I was an art major in high school, and found my convoluted way into the world of radiologic technology as
a result of an unlikely career “intervention” by a family
friend who was an orthopedic surgeon. As an artist, I
was skeptical that science would hold my interest, but
believed it to be a more viable means to my life as an
independent adult. Almost 40 years ago, as I waited
for that first image to come out of the processor, I was
already on my way to a serious addiction. The darkroom, the view box lights, my communication skills and
knowledge of anatomy, the buttons, knobs, and dials on
the control panel and tube housing were now my new
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
477
Yvonne Balzano, BS, R.T.(R)(M)
Saco, Maine
Open Forum
In the Interest of Clarity
artist’s palette. I had already known the beauty of creating something, but by the time that first radiograph
came out, I had a new medium, and I was hooked.
This is why I was so entertained and enlightened
by Dr Hom’s article. Although we freely toss about the
phrase, I have not seen anyone make a solid connection
between the art and science of radiologic technology
until I read his article. I am grateful for Dr Hom’s artful
insight into our technology and thank him for giving
me one of the best little moments of my adult life as
I curled up on my couch to read my journal and connected with a profession that I will always treasure. It
has brought beauty and comfort into my life in the form
of colleagues, patients, and images. Thanks to Dr Hom
for reminding me of my personal connections with my
profession.
Ann T Verschuuren, MEd, R.T.(R)(M)
Highland Lakes, New Jersey
478
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
An R.T.’s Best
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Backscatter
If you have an interesting image
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Narrow-minded
Archive
Coronal MIP
Axial MIP
The vertebral arteries supply oxygenated blood to the posterior part of the brain. Stenosis is
the constriction or narrowing of the arterial lumen, most often the result of atherosclerosis.
Symptoms vary according to the degree of stenosis. Patients might present with stroke or
transient ischemic attack symptoms such as visual changes, dizziness, speech difficulty, or
numbness or weakness in an arm or leg. A 48-year-old woman presented to the emergency
department with a sudden onset severe headache, visual changes, and extreme sensitivity to light.
The magnetic resonance (MR) image on the left is a coronal maximum-intensity projection
(MIP) from an MR angiography (MRA) scan showing stenosis of the left vertebral artery
(arrow). On the right is an axial MIP from the same MRA scan showing the severity of the
stenosis more visibly (arrow). These images appear in MR Basics: Module 11 – Pathology Part
1. For more information, visit www.asrt.org/mrbasics.
Radium: Its
Discovery
and Its
Discoverers.
The X-Ray
Technician,
March 1961.
Marie Curie’s
name will
be immortal
as long as the human race exists, not
only because her discovery of radium
marked the beginning of modern
atomic physics as we know it today,
but also because radium, as a tool in
the hands of the medical profession
has become a powerful instrument of
healing.
Read the full story at
www.asrt.org/archive.
You Might Have Missed…
“The U.S. Radiologic Technologist Study, underway
since 1982, is the largest study incorporating medical
professionals who are exposed to ionizing radiation.”
Turn to Page 460 for the full story.
What new technology or equipment do you use to reduce exposure to ionizing radiation? Share with your Community at
www.asrt.org/myasrt.
480
RADIOLOGIC TECHNOLOGY, March/April 2016, Volume 87, Number 4
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Earn up to 14 CE credits and receive a document recognizing your achievement once you successfully complete all 10 modules.
We also offer individual credit modules and an institutional/educator series for classroom use or training.
Focuses on quality patient care and prevention of medical errors as outlined in The Joint Commission
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