Download Radiography Students` Clinical Learning Styles Bleeding Risks in

RADIOLOGIC
®
Journal of the American Society of Radiologic Technologists
Vol. 81, No. 6
July/August 2010
Radiography Students’ Clinical Learning Styles
Bleeding Risks in Interventional Radiology
Factors Related to Radiation Safety Practices in California
Diagnosis and Treatment of Ocular Disorders
American Society of
Radiologic Technologists
Update Your
Professional
Skill Set
Earn CE credit with these popular and animated
courses and keep up with the expanding influence
of computed tomography.
Get started at www.asrt.org/CTBasics.
CT Basics :
Module 1 – Fundamentals
Module 2 – Equipment
and Instrumentation
Module 3 – Data Acquisition
Module 4 – Image Processing
and Reconstruction
Module 5 – Patient Safety
Module 6 – Image Quality
Module 7 – Procedures
Module 8 – Cross-sectional Anatomy
of the Head and Neck
Module 9 – Cross-sectional Anatomy
of the Chest, Abdomen and Pelvis
Module 10 – Additional Applications
Successfully complete all 10 for-credit modules and receive a diploma from the ASRT!
Also available: Institutional version licensed for education and staff trainings.
CT Basics
A New Interactive Series
essentialeducation
©2009 ASRT. All rights reserved.
A wide new window of opportunity
1,2
Introducing ABLAVAR®: the first and only blood-pool contrast agent for MRA1,2
A low-dose MRA contrast agent with the unique benefits of albumin binding3
• Time to acquire high-resolution first-pass and steady-state images3
• Imaging window up to 1 hour with a single, low-dose (0.12 mL/kg body
weight [0.03 mmol/kg]) IV bolus1,3
• Diagnostic accuracy comparable to conventional X-ray angiography4,5
• Documented safety and tolerability with no reported cases of NSF* 6
*No reported cases of nephrogenic systemic fibrosis (NSF) to date in clinical use with nearly 90,000 patients outside of the United States.
References: 1. ABLAVAR® [package insert]. North Billerica, MA: Lantheus Medical Imaging, Inc.; 2009. 2. U.S. Food and Drug Administration Web site. http://www.fda.gov/
drugs. Accessed February 1, 2010. 3. Goyen M. Gadofosveset-enhanced magnetic resonance angiography. Vasc Health Risk Manag. 2008;4(1):1-9. 4. Goyen M, Edelman
M, Perreault P, et al. MR angiography of aortoiliac occlusive disease: a phase III study of the safety and effectiveness of the blood-pool contrast agent MS-325. Radiology.
2005;236(3):825-833. 5. Rapp JH, Wolff SD, Quinn SF, et al. Aortoiliac occlusive disease in patients with known or suspected peripheral vascular disease: safety and efficacy
of gadofosveset-enhanced MR angiography–multicenter comparative phase III study. Radiology. 2005;236(1):71-78. 6. Data on file, Lantheus Medical Imaging, Inc.
INDICATIONS: ABLAVAR® is indicated for use as a contrast
agent in magnetic resonance angiography (MRA) to evaluate
aortoiliac occlusive disease (AIOD) in adults with known or
suspected peripheral vascular disease.
CONTRAINDICATIONS: History of a prior allergic
reaction to a gadolinium-based contrast agent.
IMPORTANT SAFETY INFORMATION:
WARNING: NEPHROGENIC SYSTEMIC FIBROSIS
(NSF) Gadolinium-based contrast agents
increase the risk of nephrogenic systemic
fibrosis (NSF) in patients with:
• acute or chronic severe renal insufficiency
(glomerular filtration rate <30 mL/
min/1.73m2), or
• acute renal insufficiency of any severity due
to the hepato-renal syndrome or in the
perioperative liver transplantation period.
In these patients, avoid use of
gadolinium-based contrast agents
unless the diagnostic information is
essential and not available with noncontrast enhanced magnetic resonance
imaging (MRI). NSF may result in
fatal or debilitating systemic fibrosis
affecting the skin, muscle, and internal
organs. Screen all patients for renal
dysfunction by obtaining a history and/
or laboratory tests. When administering
a gadolinium-based contrast agent, do
not exceed the recommended dose and
allow a sufficient period of time for
elimination of the agent from the body
prior to any re-administration.
To order, call 1-800-299-3431
www.ABLAVAR.com
ABLAVAR® is a registered trademark of
Lantheus Medical Imaging, Inc.
© 2010 Lantheus Medical Imaging, Inc.
All rights reserved. Printed in USA. AB-JA-May 2010
ABLAVAR® Injection: As with other contrast
media: the possibility of serious or life-threatening
anaphylactic or anaphylactoid reactions, including
cardiovascular, respiratory and/or cutaneous
manifestations, should always be considered. As with
other paramagnetic contrast agents, caution should be
exercised in patients with renal insufficiency due to the
possibility of further deterioration in renal function.
In clinical trials, a small increase (2.8 msec) in the average
change from baseline in QTc was observed at 45 minutes.
These QTc prolongations were not associated with arrhythmias
or symptoms. Caution should be used in patients at high risk
for arrhythmias due to baseline QTc prolongation.
Have emergency resuscitative equipment available prior to and
during ABLAVAR® administration.
Please see brief summary, including boxed WARNING regarding
Nephrogenic Systemic Fibrosis (NSF), on the following page.
An Official Journal
Radiologic Technology (ISSN 0033-8397) is the
official scholarly/professional journal of the
American Society of Radiologic Technologists. It
is published bimonthly at 15000 Central Ave SE,
Albuquerque, NM 87123-3909. Months of issue are
January/February, March/April, May/June, July/
August, September/October and November/December. Periodical class postage paid at Albuquerque, NM, and at additional mailing offices. Printed
in the United States. ©2010 American Society of
Radiologic Technologists.
The research and information in Radiologic
Technology are generally accepted as factual at
the time of publication. However, the ASRT and
authors disclaim responsibility for any new or
contradictory data that may become available after
publication. Opinions expressed in the Journal are
those of the authors and do not necessarily reflect
the views or policies of the ASRT.
Postmaster
Postmaster: Send change of address to
Radiologic Technology, c/o the American Society of
Radiologic Technologists, 15000 Central Ave SE,
Albuquerque, NM 87123-3909.
Editorial
Radiologic Technology is a peer-reviewed journal
produced by the American Society of Radiologic
Technologists for the benefit and advancement of
all technological disciplines within medical imaging
and radiation therapy. Editorial correspondence
should be addressed to Radiologic Technology Editor,
15000 Central Ave SE, Albuquerque, NM 871233909. Phone 505-298-4500, 8 a.m. to 4:30 p.m.
Mountain time; e-mail [email protected].
Letters of inquiry prior to finished manuscript
production are encouraged and frequently will be
reviewed by both the editor and the chairman of the
Editorial Review Board.
The initials “R.T.” following proper names in
this journal refer to individuals certified by the
American Registry of Radiologic Technologists.
Subscriptions, Change of Address
ASRT member change of address: Address
correspondence to the American Society of
Radiologic Technologists, Attention: Member
Services, 15000 Central Ave SE, Albuquerque, NM
87123-3909. Call the ASRT office from 8 a.m. to
4:30 p.m. Mountain time at 800-444-2778; fax 505298-5063. ASRT members also can submit changes
of address online at www.asrt.org/myinfo.
Nonmember subscriber change of address:
Send an old mailing label and the new address,
including ZIP code, at least 6 weeks in advance
to ASRT, Attention: Member Services, 15000
Central Ave SE, Albuquerque, NM 87123-3909.
Claims are not allowed for issues lost as a result
of insufficient notice of change of address. The
publisher cannot accept responsibility for undelivered copies.
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
Subscription rates and order processing:
Member subscription is $7.03 per year, included
in ASRT member dues. Nonmember subscription
of one volume of 6 issues is $70 within the United
States for individuals; foreign, $105, including
Canada. Institutional rates also are available. Discounted rates apply to 2- and 3-year subscriptions
and subscription agencies. Single issues, both current and back, exist in limited quantities and are
offered for sale. For prices and availability, phone
ASRT Member Services at 800-444-2778. Journal
orders must be paid in advance by check, money
order or credit card drawn on a U.S. bank in U.S.
funds only. Send payment to ASRT, PO Box 27447,
Albuquerque, NM 87125-7447. Prices are subject
to change.
Advertising
All commercial display advertising and classified
advertising is handled by the ASRT Corporate Relations Department, 15000 Central Ave SE, Albuquerque, NM 87123-3909. For information on rates and
deadlines, contact JoAnne Quirindongo at 800-4442778, Ext. 1317, or e-mail [email protected].
Radiologic Technology reserves the right to reject
or revise any advertising copy that it considers
objectionable, either because said copy is not
consistent with usual professional standards of
propriety or for any other reason deemed material.
In any event, the advertiser assumes full liability for
the content of all advertising copy printed.
All advertising materials submitted become
the property of ASRT. Advertisements submitted
beyond the deadline for proof service are done so
at the advertiser’s risk. Publication of an advertisement in Radiologic Technology does not imply endorsement of its claims by the editor or publisher.
For advertising specifically related to educational
programs, ASRT does not guarantee, warrant,
claim or in any way express an opinion relative to
the accreditation status of said program.
Rights Reserved
All articles, illustrations and other materials
carried herein are pending copyright under U.S.
copyright laws, and all rights thereto are reserved by
the publisher, the American Society of Radiologic
Technologists. Any and all copying or reproduction
of the contents herein for general distribution, for
advertising or promotion, for creating new collective
works or for resale is expressly forbidden without
prior written approval by the publisher and, in some
cases, the authors.
Copying for personal use only through application and payment of a per-copy fee as required
by the Copyright Clearance Center Inc, under
permission of Sections 107 and 108 of the U.S.
copyright laws. Violators will be prosecuted.
Member of
BPA International
517
Radiologic
Technology
Editorial
Review Board
Chairman
Laura Carwile Aaron, PhD, R.T.(R)(M)(QM)
Northwestern State University
Shreveport, Louisiana
Vice Chairman
Nina K Kowalczyk, PhD, R.T.(R)(CT)(QM), FASRT
The Ohio State University
Columbus, Ohio
Members
Sarah S Baker, EdD, R.T.(R), FASRT
Indiana University School of Medicine
Indianapolis, Indiana
Melissa B Jackowski, EdD, R.T.(R)(M)
University of North Carolina
Chapel Hill, North Carolina
James Johnston, PhD, R.T.(R)(CV)
Midwestern State University
Wichita Falls, Texas
James Kilmartin, R.T.(R), FACHE, FAHRA
Stormont-Vail HealthCare
Topeka, Kansas
Tricia Leggett, DHEd, R.T.(R)(QM)
Zane State College
Zanesville, Ohio
Michael E Madden, PhD, R.T.(R)(CT)(MR)
Fort Hays State University
Hays, Kansas
Kimberly Metcalf, EdD, R.T.(R)(T)
Massachusetts General Hospital
Institute of Health Professions
Boston, Massachusetts
Bette Schans, PhD, R.T.(R), FASRT
Mesa State College
Grand Junction, Colorado
Diane Scutt, PhD
University of Liverpool
Liverpool, United Kingdom
Bettye G Wilson, MEd, R.T.(R)(CT),
RDMS, FASRT
University of Alabama at Birmingham
Birmingham, Alabama
Jeffrey S Legg, PhD, R.T.(R)(CT)(QM)
Virginia Commonwealth University
Richmond, Virginia
ASRT Journal Staff
Kathryn Faguy, ELS, publications manager
Ellen Lipman, director of professional development
Julie James-Griego, art director
Marge Montreuil, graphic designer
Laura Reed, graphic designer
Loren Stacks, graphic designer
JoAnne Quirindongo, advertising and
sponsorship manager
ASRT Office
15000 Central Ave SE
Albuquerque, NM 87123-3909
Phone: 800-444-2778; Fax: 505-298-5063
For advertising information, phone
JoAnne Quirindongo, advertising and
sponsorship manager, at Ext. 1317, or
e-mail [email protected].
For questions regarding subscriptions or
missing issues, phone Member Services at
800-444-2778 or e-mail [email protected].
518
For questions about submitting an article,
e-mail [email protected].
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
Dynamic phase information
Hepatocyte-specific
functional information
Redefining liver imaging
See more with EOVIST—
As compared to pre-contrast MRI, EOVIST-enhanced MRI provides:
QImproved lesion detection, localization, and characterization (p<0.001)1
QMore information for treatment decisions
– In a clinical study of 131 patients previously scheduled for surgery, EOVIST-enhanced
MRI led to a change in surgical therapy in 13.0% of cases versus 6.9% for pre-contrast MRI2
Indications and Usage
EOVIST® (gadoxetate disodium) Injection is a gadolinium-based contrast agent indicated for intravenous use in
T1-weighted magnetic resonance imaging (MRI) of the liver to detect and characterize lesions in adults with known or
suspected focal liver disease.
BAYER, the Bayer Cross, and Eovist are registered trademarks of Bayer.
© 2010, Bayer HealthCare Pharmaceuticals Inc., Wayne, NJ 07470.
All rights reserved. May 2010. 320-10-0006-10b
Important Safety Information
WARNING: NEPHROGENIC SYSTEMIC FIBROSIS
Gadolinium-based contrast agents increase the risk for nephrogenic systemic fibrosis (NSF) in patients with:
• acute or chronic severe renal insufficiency (glomerular filtration rate <30 mL/min/1.73m2), or
• acute renal insufficiency of any severity due to the hepato-renal syndrome or in the perioperative liver
transplantation period.
In these patients, avoid use of gadolinium-based contrast agents unless the diagnostic information is essential and
not available with non-contrast enhanced magnetic resonance imaging (MRI). NSF may result in fatal or debilitating
systemic fibrosis affecting the skin, muscle and internal organs. Screen all patients for renal dysfunction by
obtaining a history and/or laboratory tests. When administering a gadolinium-based contrast agent, do not exceed
the recommended dose and allow a sufficient period of time for elimination of the agent from the body prior to
any readministration.
The possibility of serious or life-threatening anaphylactoid/hypersensitivity
reactions with cardiovascular, respiratory and/or cutaneous manifestations
should always be considered. The most common adverse reactions observed
in clinical trials at the recommended dose included feeling hot, nausea
and headache.
Please see Brief Summary on adjacent page.
For more information and full prescribing information, please contact
your Bayer Imaging Sales Consultant or call 1-888-84-BAYER.
1. Huppertz A, Balzer T, Blakeborough A, et al. Improved detection of focal liver lesions at MR imaging:
multicenter comparison of gadoxetic acid-enhanced MR images with intraoperative findings. Radiology.
2004;230:266-275. 2. Data on file. Bayer HealthCare Pharmaceuticals.
www.eovist.com
...................................................................
GUIDE FOR AUTHORS
Peer-review Submissions Sought
Guide for Authors is
presented as an aid to writers
who want to contribute articles
to Radiologic Technology.
Please direct any questions
via correspondence to
[email protected].
Radiologic Technology welcomes written
contributions from the profession. Peerreviewed articles should reflect original
research or thought and be previously
unpublished. Manuscripts should not be
under consideration by other publishers
at the time of submission.
Typically, peer-reviewed manuscripts
focus on quantitative research or technical or literature review. An author
conducting quantitative research poses a
question or hypothesis and then collects
and analyzes data to answer the question or prove the hypothesis. Technical
manuscripts describe a new practice
technique, including historical background and implications for practice.
Literature review manuscripts analyze
previously published material on a specific topic, summarizing the research
and drawing original conclusions.
Preparing and Submitting
A Manuscript
The ASRT website (www.asrt.org)
provides a Guide for Authors. Go to
Publications > Publication Resources
> Guide for Authors. Potential authors
can choose several links, including a
page on the Peer-reviewed Manuscript
and Submitting a Peer-reviewed Article.
Authors must submit manuscripts
electronically. The Guide for Authors
explains the process and provides a
link to the submission site (www.editorialmanager.com/radt).
The Peer-review Process
These manuscripts are forwarded
to the chairman of the ERB, who then
assigns them to reviewers. The review
process normally takes approximately
8 weeks. A manuscript can be accepted
as submitted, returned for revisions or
rejected. Manuscripts may be edited
to conform to Journal style and space
restrictions. ◆
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
Now an 80% dose
reduction can mean...
.................................................................................. . . . . . . . . . . . . . . . . . . .
CONTENTS
July/August 2010
Volume 81/Number 6
P E E R- RE VIE WE D ARTICL E S
Radiography Students’ Clinical Learning Styles
Patti Ward, Carole Makela. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 527
On the Cover: This
issue’s cover image, by
Earl Keleny of Madison,
Wisconsin, was inspired by
the Directed Reading article
“Diagnosis and Treatment
of Ocular Disorders.”
Factors Related to Radiation Safety Practices
In California
Janet Thompson Reagan, Anita Marie Slechta. . . . . . . . . . . . . . . . . . . . . . . . 538
D I R ECTE D RE ADIN G ARTICL E S
Bleeding Risks in Interventional Radiology
Amy Morris. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 548
Diagnosis and Treatment of Ocular Disorders
Janet Yagoda Shagam. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 565
C OL U MN S & DE PARTME N TS
Technical Query . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 523
On the Job 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 597
My Perspective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 599
Teaching Techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 602
On the Job 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 606
Writing & Research. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 610
Patient Page. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 615
522
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
...................................................................
TECHNICAL QUERY
Making Waves
Olive Peart, MS, R.T.(R)(M),
is a clinical instructor at the
Stamford Hospital School of
Radiography in Connecticut.
Ms Peart is the author of
Spanish for Professionals in
Radiography, Lange Q & A:
Mammography Examination
(editions 1 and 2) and
Mammography and Breast
Imaging: Just the Facts.
“Technical Query” is a
troubleshooting column that
covers image acquisition and
processing.
Sometimes even radiolucent objects
can create imaging artifacts. Although
this is more common in the lower kV
range, occasionally we can be surprised.
In this case, the patient was an
80-year-old woman who had a chest
x-ray exam that had been ordered for
chest pain. The anteroposterior projection showed no abnormality but the
lateral projection demonstrated what
appeared to be a soft-tissue mass directly
posterior to the heart (see Figure).
Imaging was performed in the emergency department. The patient was
unsteady, so both projections were taken
with her seated on a stretcher (cart).
The “mass” actually was created by
the wedging of a 45º sponge and blanket
behind the patient. The sponge and
blanket pushed up the patient’s skin,
which created the soft tissue-like density. The wavy lines actually are artifacts
from the blanket.
With the objects removed, a repeat lateral radiograph showed no wavy lines and
that the patient did not have a mass. ◆
Thanks to Patty Sorensen, R.T.(R)
(BD), retired clinical facilitator at Century
College in St Paul,
Minnesota, for this
month’s technical
query.
Figure. Lateral projection of the chest in an 80-year-old
woman shows what appears to be a soft-tissue mass (arrows).
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
…a cleaner image with
the patient in mind.
Associated Sciences Program at RSNA 2010
Refresher Courses
Sponsored by the Associated Sciences Consortium
(Each refresher course is approved for 1.5 AMA PRA Category 1 Credits™
and Category A+ credit for technologists)
Monday, November 29
AS21 8:30 AM – 10:00 AM
Ethical Dilemmas: Regulatory and
Business Ethics in Medicine Today
Karen J. Finnegan, MS, RT(R)(CV), FAVIR
Moderator
Richard Duszak Jr, MD
Frank J. Lexa, MD
Michael Delvecchio, BS, RT(R), (ARRT)
AS22 10:30 AM – 12:00 PM
Ethical Dilemmas: The Vital Role
of Ethics in Clinical Excellence
Karen L. Green, RN, BSN, MHA, CRN
Moderator
Nabile M. Safdar, MD
Richard B. Gunderman, MD, PhD
AS23 1:30 PM -3:00 PM
Picking Up the Pieces: Forensic
Radiography Following Mass
Disasters
Susan Crowley, BAppSc(MI), MRT(R) MA (Ed)
Moderator
Mark Viner, FCR, MSc, HDCR(R)
AS24 3:30 PM – 5:00 PM
Imaging Facility Design in an Age
of Diminishing Resources
Morris A. Stein, FAIA, FACHA , B. Arch
Moderator
Morris A. Stein, FAIA, FACHA , B. Arch
Ronald L. Arenson, MD
Bill Rostenberg, FAIA, FACHA
Steven C. Horii, MD
Tuesday, November 30
AS31 8:30 AM –10:00 AM
Who’s Driving Radiology:
Trends in Hospital/Radiologist
Alignment
Donna Blakely, MS, RT(R)(M)(CRA), Moderator
Shay Pratt
AS32 10:30 AM –12:00 PM
The Clinical Impact of Molecular
Imaging
Charles Stanley, RT(R)(CT)(MR), Co-Moderator
David Gilmore, MS, CNMT, NCT, RT(R)(N)
Co-Moderator
A) The Growing Influence of PET/CT
Clinical Decision-Making
Nancy M. Swanston, CNMT, RT(N), PET
B) Clinical Trials Network: The Impact
Today
Kathy Hunt, MS, CNMT
AS33 1:30 PM – 3:00 PM
New Regulations and Their
Impact on Radiology Practice
Claudia A. Murray, Moderator
William A. Sarraille, JD
James P. Borgstede, MD
AS42 10:30 AM – 12:00 PM
Imaging Through Cross-cultural
Lens: A Global Perspective on
Ethics, Standards, and Human
Resource Issues
Arlene M. Adler, MEd, RT(R), FAEIRS, Moderator
Cynthia Cowling, ACR, B.Sc, M.Ed
Lori Boyd, MRT(R), BA, MA
AAPM/RSNA Basic Physics Lecture
for the Radiologic Technologist
(Approved for 1.25 AMA PRA Category 1 Credits
and Category A+ credit for technologists)
Monday, November 29, 1:30 PM – 2:45 PM
Hybrid Imaging
Douglas E. Pfeiffer, MS, Moderator
AS34 3:30 PM – 5:00 PM
Gary Sayed
A) SPECT/CT
Randell L. Kruger, PhD
B) PET/CT
Managing Risk for Optimal
Patient Safety
Ellen Lipman, MS, RT(R)(MR), CAE, Moderator
A) Practical Methods for Creating a
Culture of Safety in the Workplace
B) Patient Safety: A Clinical Perspective
Karen L. Green, RN, BSN, MHA, CRN
Registration Information
Sponsoring Organizations
Advance discounted registration
for the RSNA annual meeting ends
November 5, 2010. Register now to get
the hotel of your choice.
• AHRA: The Association for Medical Imaging
Management
• American Institute of Architects – Academy on
Architecture for Health (AIA-AAH)
• Association for Radiologic & Imaging Nursing
(ARIN)
• American Society of Radiologic Technologists
(ASRT)
• Association of Educators in Imaging and
Radiologic Sciences, Inc (AEIRS)
• Association of Vascular and Interventional
Radiographers (AVIR)
If you would like a copy of the published Associated Sciences Proceedings, please call 1-877-776-2227.
Radiology’s Changing Dynamics
Donna Blakely, MS, RT(R)(M)(CRA), Moderator
Melody W. Mulaik, MSHS
Thomas W. Greeson, JD
Barbara Rubel, MBA
Charles Stanley, RT(R)(CT)(MR)
Registration is required to attend the
Associated Sciences programs at
RSNA2010.RSNA.org.
Wednesday, December 1
AS41 8:30 AM – 10:00 AM
RSNA is an ARRT®-approved Recognized Continuing
Education Evaluation Mechanism Plus (RCEEM+) and
will provide Category A+ continuing education credits
for technologists and radiologist assistants.
• Canadian Association of Medical Radiation
Technologists (CAMRT)
• International Society of Radiographers and
Radiological Technologists (ISRRT)
• Radiology Business Management Association
(RBMA)
• Section for Magnetic Resonance Technologists
(SMRT-ISMRM)
• Society of Nuclear Medicine Technologists
Section (SNMTS)
What inspired our high-quality, low-dose Ct innovation?
exposing less and revealing more.
Lower radiation dose levels don’t have to mean lower image quality. The Philips iDose feature reduces the noise
and artifacts that result from a lower radiation dose. Now, you can reduce the dose by up to 80% and still maintain
diagnostic image quality. It is our latest evolution of DoseWise radiation management, our
commitment to high image quality at a low dose. To see
for yourself, take the challenge at www.philips.com/iDoseAd.
*Because our innovations are inspired by you.
ASRT Congratulates
Winners
the 2009-2010
of the
Jean I. Widger Distinguished Author Award and the Harold Silverman Distinguished Author Award,
honoring the best peer-reviewed articles published in the ASRT journals during the past year.
Nina Kowalczyk,
Elizabeth Comer,
Ph.D., R.T.(R)(QM)(CT), FASRT, and
B.S., R.T.(R),
are the winners of the Widger award for their article “Exposure Indicator Degradation From
CR Plate Processing Delays,” which appeared in the May/June 2009 issue of Radiologic
Technology.
Craig Opie,
Kelly Elsner
BAppSc(MR), Grad Dip AEd(VET), MVET, and
, BAppSc(MRS),
received the Silverman award for their article “Using Simulations To Train Students in Treatment Planning,” published in the spring 2010 issue of Radiation Therapist.
©2010 ASRT. All rights reserved.
............................................................................. . . . . . . . . . . . . . . . . . . . . . .
PEER REVIEW
Radiography Students’
Clinical Learning Styles
PATTI WARD, PhD, R.T.(R)
CAROLE MAKELA, PhD
Purpose To examine the common learning styles of radiography students during clinical practice.
Methods Descriptive research methodology, using a single self-report questionnaire, helped to identify common learning styles of radiog-
raphy students during clinical practice.
Results The results indicated that 3 learning styles predominate among radiography students during clinical practice: task oriented,
purposeful and tentative.
Conclusion Insight into clinical practice learning styles can help students understand how they learn and allow them to recognize ways
to maximize learning. It also heightens awareness among clinical instructors and technologists of the different learning styles and their
relevance to clinical practice education.
C
linical practice is an important aspect of
the radiologic science curriculum. To
earn recognition by the American
Registry of Radiologic Technologists
(ARRT), candidates must meet requirements that demonstrate competency in general patient
care activities and radiologic procedures.1 The foundation for clinical practice is authentic and direct experience in a medical facility. Radiographers, as well as
other health care professionals, depend on practical
experiences to demonstrate and develop knowledge
and skills from academic and laboratory experiences.
Students gain academic knowledge of fundamental
concepts and theories in the classroom and laboratory
and through related homework before and during their
participation in clinical experiences.
In a recent qualitative study, Fortsch examined
clinical instructors’ and students’ learning perceptions
in the clinical setting.2 Results indicated that clinical
instructors observed different treatment of students
based on aspects of their learning style behavior. For
example, clinical instructors noticed that students who
were seen as “more capable and aggressive in their
learning style received more positive attention from
instructors and technologists,” yet “students with passive, but effective learning styles, were judged to be lazy,
lacking initiative or unmotivated.”2 Students indicated
preferences for practical, authentic learning experiences, and for technologists or clinical instructors
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
who accommodated their learning styles. Variations in
students’ and instructors’ perceptions suggest that students, clinical instructors and technologists would benefit from understanding how learning styles shape the
learning process and help develop higher-performing
radiographers.
In education, the academic classroom has been the
venue for research in learning styles.3-7 Educational
theory about learning styles has favored learning in
classroom conditions rather than in work-based situations. 8 There has been limited research that addresses
learning styles in a work environment such as clinical
practice.
Literature Review
Background on Learning Style Theory
The desire to understand and improve the way individuals learn has created widespread interest in learning
style theory and assessment. Coffield et al identified
71 models of learning styles, published between 1909
and 2002, that reflected the theoretical and practical
complexity associated with developing learning style
theories and assessments.9 Because of this complexity,
several researchers developed conceptual frameworks of
learning style theories as a way to understand how the
styles described different aspects of learning.9-14 Each
conceptual framework explicitly or implicitly recognized
that different learning style models represented stable or
changeable characteristics. It is important to understand
527
...........................................................................................................
CLINICAL LEARNING STYLES
whether a researcher
Table 1
considers learning
Perspectives of Learning Styles
styles as stable traits
Perspective
Stable Trait
Flexibly Stable
Changeable
we inherit or shifting
Preference
Approach
states that can change
over time.
Transformation of
Remains stable
Adaptable but retains Changes with each
Coffield et al’s
style over time
style structure
experience or task
conceptualization
Modified learning
Implications for the Matching educational Styles can fluctuorganized learning
situations can promote
way learning styles intervention with stu- ate moderately to
style theories into 5
dent’s style can meet meet demands of the change to compenaffect learning
families of styles based
sate for or strengthen
learning situation
individual needs
on aspects of learning
weaknesses
that ranged from easily changed to more
and the purpose for using it. Assessments from the staresistant to change.9 Table 1 is based on a modification
ble trait group of learning styles might not be suitable
of Coffield et al’s categorization of learning styles, and
for clinical environments because of impracticality.5,15
shows the perspectives of learning styles as stable traits,
Authentic learning environments, such as clinical pracflexibly stable preferences and changeable approaches
tice, do not provide the flexibility necessary to modify
with implications for the way style affects learning. This
learning situations recommended by theorists from the
conceptualization provides a way to examine how difstable trait perspective of learning styles. Because cliniferent learning style theories potentially relate to differcal education differs from the classroom and laboraent learning environments and influence educational
tory learning environments and related homework, an
interventions.
assessment appropriate for examining learning styles
When viewed as a stable trait, learning style is stable
should include the objectives of learning found in cliniover time for an individual. From this standpoint, theocal experience (see Table 2).
rists promote customized learning situations to meet
Educators and researchers associated with profesindividual needs based on a student’s learning style.
sions that include practical experience as part of
For example, group work would be an educational
preparation often turn to Kolb’s experiential learning
intervention for a student with a known preference for
theory that recognizes learning by experience.16 Kolb
learning with peers.
defined learning as “the process whereby knowledge is
When viewed as a flexibly stable learning prefercreated through the transformation of experience.”16
ence, styles are adaptable, but retain style structure
Experiential learning centers on an assumption that peoover time. Theorists with this point of view believe
ple learn differently and one of the ways people learn is
styles fluctuate moderately according to the learning
from experience. Coffield et al categorized Kolb’s model
situation. For example, individuals with a preference
as a flexibly stable learning style.9 This means the assessfor abstract learning can adapt somewhat to a variety of
ment characteristics of learning are fairly stable, yet flexlearning situations, but will still have the same preferible enough to allow educational interventions to
ence years later.
be effective.
Viewed as a changeable strategy or approach, style
Kolb identified 2 dimensions of learning: percepcan change with each experience or task. Theorists
tion and process (see Figure 1).16 Perception concerns
with this perspective examine aspects of learning
the way an individual grasps knowledge. The coninvolved in the way individuals prefer to strategize.
tinuum extends from concrete experience to abstract
For example, a deep learning approach is encouraged
conceptualization. Concrete experience describes an
when the clinical environment for students is supportinvolved approach where learning takes place through
ive and challenging.
direct experiences such as sensations, feelings and
intuition. Abstract conceptualization describes an anaLearning Style Models Pertinent to Clinical Practice
lytical approach where learning takes place through
To capitalize on what learning style models contribmental conceptualizations and symbolic representaute to the educational process, there must be linkage
tions of experience.
among a particular learning style theory, its assessment
528
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
...........................................................................................................
WARD, MAKELA
depend on others
to give him or her
guidance on how
to begin a difficult
Academic Environment
Clinical Practice Environment
learning task, and an
(Classroom, Laboratory, Related
internally regulated
Homework)
student would proceed independently.
Gain knowledge of fundamental concepts
Develop skills
Development of the
Gain knowledge of fundamental theories
Demonstrate skills
questionnaire includIntegrate theoretical knowledge
ed renaming Kolb’s
4 modes and the
Process relates to the way an individual deals with
addition of the regulation subscale (see Table 3). An
an experience along a continuum of reflection and
adaptation of a work by Hermanussen et al compares
active experimentation. Reflection describes an imparKolb’s 4 experiential learning modes to the identified 5
tial approach where learning is by means of internal
subscales of Hermanussen et al’s assessment.8
processes, such as observation and purposeful reflection on previous learning. In active experimentation,
Related Research
learning takes place through external processes such as
No reported research has specifically examined the
acting on or testing previous learning. Kolb conceptuallearning styles of radiography students during clinical
ized learning style as the characteristic ways individuals
practice. The few studies that have investigated learnresolve conflict between the 2 dimensions of perceping styles of radiography students were in the context
tion and process.16
of the academic classroom.17-19 A study in the United
Hermanussen et al integrated aspects of Kolb’s
Kingdom investigated learning styles of radiologic techmodel that suited work-based education and discarded
nologists.20 The learning context was continuing pro8,16
aspects that were not pertinent. The Hermanussen
fessional development, which typically takes the form
team accepted Kolb’s 4 learning modes
of concrete experience, reflective observation, abstract conceptualization and
active experimentation, and used them
as a starting point for describing styles
in work-based learning. Hermanussen et
al criticized the dimensionality of Kolb’s
perception and process dimensions, citing “insufficient empirical evidence of
the existence of the two dimensions.”8
In response to criticism that the
model failed to acknowledge external
social influences, Hermanussen et al
added regulation as a fifth subscale.8
Regulation concerns strategies students use to manage or organize their
learning process. Internal regulation
describes the style of an individual who
initiates learning strategies independently. External regulation describes
the style of an individual who depends
on outside resources, such as instrucFigure 1. Kolb’s Learning Dimensions and 4 Modes. Adapted from Kolb,
tors, to regulate learning. For example,
DA. Experiential Learning: Experience as the Source of Learning and
Development. Upper Saddle River, NJ: Prentice Hall; 1984.
an externally regulated student would
Table 2
Comparison of Learning Objectives in Academic and Clinical
Practice Environments
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
529
...........................................................................................................
CLINICAL LEARNING STYLES
community college
programs. Because
the population
was geographically
diverse and access to
Kolb’s Experiential
Hermanussen et al’s Bipolar Subscale
Learning Mode
students depended
Subscale
Left Pole
Right Pole
on program affiliaConcrete experience
Immersion
Immersed
Detached
tion, recruitment of
the participants was
Reflective observation
Reflection
Insight oriented
Results oriented
through individual
Abstract
Conceptualization
Strategic
Pragmatic
program directors.
Conceptualization
Directors from 100
Active experimentation
Experimentation
Inquiring
Prescription oriented
programs were asked
to provide students
Regulation
External
Internal
the opportunity to
participate in the study. Students who had not comof formal presentations or home study, rather than
pleted a minimum of 30 hours of clinical practice were
clinical practice. Studies in other health care profesexcluded because they would be unable to draw on
sions have used Kolb’s learning style inventory to assess
current experiences to respond appropriately to the
students.21-27 However, none of these studies examined
questionnaire.
learning styles during clinical practice.
The need for a learning style assessment, specifiInstrumentation
cally for clinical practice, is clear. Evidence supports a
The LSCPQ, adapted from the QPL,8 assessed
need to examine clinical and academic learning styles
self-reported learning styles of radiography students.
separately. Kolb’s model is attractive for use in assessing
Based on Kolb’s 1985 Learning Styles Inventory (LSI),
learning styles,16 but several weaknesses hinder it from
the QPL was developed to assess styles vocational stubeing a good option for evaluating learning styles in
dents use to learn during work-based experiences. The
clinical practice. The Questionnaire Practice-Oriented
QPL reported Cronbach’s alphas between 0.62 and
Learning (QPL) 8 developed specifically to evaluate
0.70 for subscales when studying senior secondary stulearning in work-based situations was the best choice
dents from health care and engineering departments
for the purpose of this study.
in a Dutch vocational school. Generally, minimum correlation coefficients of approximately +0.70 are acceptMethods
able for group comparison.28 The QPL was appropriate
Descriptive research methodology that used a
as a model for this study because it incorporated theosingle self-report questionnaire identified common
retical concepts of experiential learning and addressed
learning styles of radiography students during clinical
unique aspects related to learning in a work-based
practice. The Learning Styles during Clinical Practice
environment.
Questionnaire (LSCPQ), so named for this study, was
The LSCPQ included 55 paired statements that
adapted from the QPL.8 Associate degree radiography
flanked a response scale. The type of response was
students completed the questionnaire electronically.
a 1 to 5 scale. The selection of 1 indicated agreement with the left statement, while the selection
Participants
of 5 indicated agreement with the right statement.
The target population was radiography students
Modifications to the original questionnaire (QPL)
enrolled in Joint Review Committee on Education in
included substitution of terms more appropriate for
Radiologic Technology (JRCERT) associate degree
student radiographers. For example, “procedure”
college/university and community college programs in
replaced “tasks in the workbook.” Table 4 presents 3
the United States and Puerto Rico. JRCERT-accredited
sample LSCPQ statements.
programs were selected because they share similar
Demographic questions included students’ level in
standards of practice. Programs were selected based
the program, highest level of education completed,
on a simple random sampling from a sampling frame
hours in clinical practice during the most recent week,
of all JRCERT associate degree college/university and
Table 3
Hermanussen et al’s Bipolar Subscales Related to Kolb’s Experiential
Learning Modes8
530
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
...........................................................................................................
WARD, MAKELA
Table 4
Sample Pairs From Learning Styles in Clinical Practice Questionnaire
(LSCPQ)
the most recent week
(see Table 5).
Six Subscales of the
LSCPQ
Confirmatory
facLeft Pole
Right Pole
tor analysis of the origI try to discover why tasks have a specific
As I perform tasks, I do not bother about
inal 5 subscales found
sequence.
understanding the specific sequence.
lower-than-desired facI enjoy trying out things, even if I do not
I would rather work according to a welltor loadings and reliknow how they will turn out.
tested procedure.
abilities (immersion,
0.56; reflection, 0.70;
After finishing a task, I expect my instructor
After finishing a task, I check whether I
conceptualization,
or a technologist to tell me whether I
understood things well or not.
0.63; experimentation,
understood things well.
0.64; and regulation,
0.64). Further analysis
sex and age. Descriptive analyses of student demoof subscales determined 6 new subscales for the LSCPQ.
graphic data included frequencies, means and standard
Exploratory factor analysis of the 55 paired LSCPQ
deviations for level in program (2 levels), level of edustatements, based on initial eigen values > 1.5, found
cation (5 levels), time in clinical practice (4 levels), sex
that 40% of the variance was explained by 7 factors.
(2 levels) and age in years (7 levels).
Following varimax rotation, statements loading ⱖ0.40
(±) were maintained. A statement was removed if it
Data Collection, Procedures and Analyses
demonstrated low loading (< 0.40) on the relevant factor
Thirty-eight program directors (38% response rate)
or showed low reliability. Seventeen statements, includagreed to provide their students with a hard copy or
ing all statements from one subscale, were removed.
e-mail cover letter that explained the purpose of the
Factor analysis of the remaining 38 paired LSCPQ
study and provided the URL to the LSCPQ. The potenstatements found 45% of variance explained by 6 new
tial number of student participants (1441) was estifactors, more than the 34% of variance explained by the
mated based on the program directors’ responses to
5 original factors. Cronbach’s alphas of the 6 subscales
the number of eligible students in their programs. Raw
(subscale score = average of statements scores) were caldata collected from the questionnaire were stored elecculated. Table 6 presents the number of statements and
tronically in numerical form in a data file. Data analyCronbach’s alpha reliability for the 6 subscales.
ses consisted of descriptive and inferential statistics.
Evaluating common themes within subscales produced the following labels and descriptions for the
Results
resulting clinical learning styles:
Descriptive and inferential statistical analyses were
■ Structure (plan–improvise) addresses the method
conducted on 38 statements of the LSCPQ with the
used to structure the learning process. Learners
sample of radiography students (N = 349; data for 1
who prefer to develop a plan tend to ask quesstudent were missing).29
tions before, during and after a learning situation.
Reflection on prior learning and experiences of
Profile of Radiography Students
others is helpful. Because these learners have a
Data were collected from 350 radiography students
plan and think about standards to meet, they are
(24% response rate) in spring 2009. Of the responable to judge their performance. On the other
dents, 75.1% were women and 24.9% were men. The
hand, learners who improvise tend to focus on a
majority of students (51.1%) were 25 years old or
task as it relates to the immediate environment.
younger. There were more second-year (53.3%) than
Viewing each experience as unconnected to prior
first-year (46.7%) students. Most students (57.6%) had
experiences, they do little to sequence tasks, quescompleted some college, and 34.9% had completed
tion or learn from experiences of others. Learners
an associate degree or higher. The majority (98.4%)
who improvise depend on others to evaluate their
spent more than 11 hours in clinical practice during
performance.
Statement
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
531
...........................................................................................................
CLINICAL LEARNING STYLES
Table 5
Profile of Radiography Students
Variable
No.
%
Sex
Male
84
24.9
Female
254
75.1
Traditional (25 years and younger)
177
51.1
Nontraditional (26 years and older)
169
48.9
Nondegree
218
65.1
Degree
117
Age
Highest education level completed
Level in program (year)
First
163
Second
186
Clinical hours during prior week
10 or fewer
11-20
142
21-30
113
31-40
85
■ Integration (active–passive) relates to efforts to
make sense of theory and practice. Active integration identifies learners who pursue cognitive
understanding of connections between theory
and practice. Those with a passive style seem to
be more interested in the practicality of a learning situation and are less concerned with making sense of the connection between theory
and practice.
■ Experimentation (investigative–conventional)
concerns tendencies to experiment during a
learning experience. Learners with an investigative inclination explore and test ideas.
Conventional-style learners prefer reliable,
detailed instructions and well-tested procedures.
■ Authority (expert–self) examines regulation of
learning. Learners with preferences for experts
depend on specialists to provide direction and evaluation as opposed to those who prefer self-reliance.
■ Orientation (results–process) involves a frame of
reference for an experience or a task. Learners
who are more results oriented prefer to focus on
532
9
outcome rather than process.
Process-oriented learners are
interested in the course of
action involved in a task.
■ Approach (insight–theory)
considers students’ bases of
reactions. Learners with a
preference for insight trust
feelings and intuition for
guidance. Those with a theoretical preference rely on
ideas, facts and principles
typically presented earlier
in the classroom.
Common Learning Styles of
Radiography Students
During Clinical Practice
46.7
Cluster analysis, a method
to identify clusters with pat53.3
terns of similar responses,
served to identify groups
2.6
of students with similar
learning styles and char40.5
acteristics. Three clusters
32.4
provided the best solution
24.4
based on discrimination and
interpretation of K-means
cluster analysis. The 3 groups were labeled as having
task-oriented (101 students), purposeful (134) and
tentative (114) learning styles. Figure 2 demonstrates
profiles of the 3 learning-style groups based on the
6 subscales.
Table 7 shows means and standard deviations of the
6 subscales by the 3 groups with highest subscale mean
scores in bold type. The task-oriented learning style
34.9
Table 6
Number of Items and Measurement
Reliabilities for LSCPQ Subscales
Subscale
Structure
Integration
No. of Items
Cronbach’s ␣
10
0.79
6
0.72
Experimentation
7
0.71
Authority
6
0.64
Orientation
3
0.62
Approach
6
0.62
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
...........................................................................................................
WARD, MAKELA
group had the highest mean scores for experimentation and approach. The purposeful learning style group
demonstrated the highest mean scores for structure,
integration and orientation; the highest mean scores for
authority were in the tentative learning style group.
Evaluation of mean subscale scores in each group
resulted in descriptions for 3 common clinical learning styles:
■ Task-oriented learners (n = 101). This clinical
learning style is characterized by preferences for
structure rather than improvising in learning
experiences. Integration of theory with practice
is modest. Learners were likely to test ideas during practical learning experiences and were
somewhat more likely to oversee their own learning experiences than depend on experts. They
focused more on results than process. During
practical learning experiences, reliance on feelings and intuition were preferred to theory for
problem solving.
■ Purposeful learners (n = 134). This clinical learning style is characterized by preferences for structured learning experiences integrating theory
with practice persistently. Reflecting and asking
questions before, during and after a task seemed
to be an integral part of efforts to integrate theory with practice. There was a balance between
testing ideas and dependence on well-defined,
well-tested procedures. These learners were somewhat more likely to prefer to manage their own
performance and more likely to focus on results
than process. During practical learning experiences, they preferred using theoretical principles
to guide decision making.
■ Tentative learners (n = 114). Learners with this
clinical learning style are slightly more likely
to plan a learning experience than they are to
improvise. Integration of theory with practice
is modest. Tentative learners in the study were
somewhat more likely to prefer explicit instructions and well-established strategies during practical learning experiences. They were as likely
to depend on experts as to rely on themselves.
Learners with the tentative style focused more on
results than process and slightly favored practice
over theory.
Similarities Among Learning Style Groups
Figure 3 demonstrates learning-style components of
radiography students as a group. In the study, radiography students tended to plan more than improvise. They
also actively, rather than passively, integrated theory
and practice. During clinical learning experiences, they
were inclined to focus on results more than process. As
a group, they were apt to rely on themselves rather than
depend on experts for guidance.
Figure 2. Profiles of LSCPQ Learning Styles.
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
533
...........................................................................................................
CLINICAL LEARNING STYLES
style differences and
relevance to clinical
practice education
may broaden the
understanding of
Task-oriented
Purposeful
Tentative
(N = 101)
(N = 134)
(N = 114)
learning style differences by clinical
Subscale
M
SD
M
SD
M
SD
instructors and tech4.35
Structure
3.76
0.45
0.32
3.36
0.55
nologists.
4.13
In clinical pracIntegration
3.43
0.71
0.50
3.24
0.65
tice,
task-oriented
3.70
Experimentation
0.44
2.87
0.63
2.45
0.58
learners preferred
2.96
Authority
2.50
0.69
2.65
0.66
0.59
to learn through
self-discovery. TaskOrientation
3.96
0.80
4.25
0.65
3.79
0.79
oriented learners
Approach
3.41
0.58
2.70
0.59
3.13
0.51
typically dealt with
practical experiDifferences Among Learning Style Groups
ences based on feelings and intuition, which likely
One-way analysis of variance (ANOVA) determined
explains a preference for practical experiences. These
whether subscale mean scores differed across the 3
learners planned moderately and focused more on
groups. F distribution ratios were significant for every
results, probably because they are most interested in
subscale. A statistically significant difference was found
the task. Hermanussen et al found a similar learning
among the groups of learning styles for structure, F2,
style in which students focused primarily on task per346 = 160.55, P = .001; integration F2, 346 = 73.32,
formance based on intuition and feeling. However, in
P = .001; experimentation, F2, 346 = 137.02, P = .001;
Hermanussen et al’s study, learning seemed to be inciauthority, F2, 346 = 14.64, P = .001; orientation, F2,
dental8 ; the present study showed there was moderate
346 = 12.33, P = .001; and approach, F2, 346 = 46.53,
integration of theory and practice.
P = .001.
It appears the intention of purposeful learners during
An appropriate post hoc test investigated group pairclinical practice was to integrate theory and practice by
wise differences. There were statistically significant differplanning the learning experience, focusing on desired
ences among the 3 learning style groups related to strucresults and using theory as a guide. Preferences to create
ture, experimentation and approach, and significant difand follow a plan, think about standards and theories
ferences between 2 of the 3 groups related to integration,
and understand how tasks relate to theory indicated
authority and orientation. Table 8 demonstrates differpatterns of abstract thinking. A slight preference for wellences in each of the learning style components among the
defined tasks and detailed instructions further supported
3 groups. Each high, mid- and low designation indicates a
the idea that purposeful learners structured their learnsignificant difference when comparing subscale scores.
ing experience based on theoretical principles. However,
because the preference was not strong, it suggests they
Discussion
might be comfortable prudently testing ideas in practice.
The results revealed there were 3 groups of common
A preference to depend on theoretical principles rather
learning styles among radiography students during
than feelings added support to purposeful learners’
clinical practice based on 6 subscales: structure, inteinterest in taking what they learned in the classroom and
gration, experimentation, authority, orientation and
applying it to skills learned during clinical experiences.
approach. Familiarity with differences in learning style
Purposeful learners tended to self-monitor their perprovides a platform for students, clinical faculty and techformance, which may indicate self-confidence based on
nologists to discuss how learning during clinical practice
prior planning, benefits of a theoretical foundation and
involves more than demonstrating and observing skills.
prerecognition of desired results.
Insight into clinical practice learning styles can help stuIn clinical practice tentative learners were conserdents understand how they learn and recognize ways to
vative in nearly every aspect of their learning style.
maximize learning. Heightened awareness of learning
They showed a modest preference to plan learning
Table 7
Means and Standard Deviations of LSCPQ Subscales for 3 Learning
Style Groups
534
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
...........................................................................................................
WARD, MAKELA
Figure 3. Similarities among radiography students.
experiences and to trust their feelings. However, they
wanted well-defined tasks, well-tested procedures and
to know what to expect in advance. These preferences
may explain why tentative learners, more than students in the other groups, were more likely to depend
on an instructor or technologist to monitor their performance. It is unclear why tentative learners reported
moderate rather than high levels of integration of
theory and practice. Could it be a perception of being
overwhelmed with the learning experience and distracted from relating theory and practice? Or might
it be a lack of motivation or lack of confidence to pursue connections between theory and practice?
insight more than theory. Task-oriented learners could
benefit from situations that help them draw out the
nuances of prior experiences. And the task-oriented
learners could help the more reticent students. For
example, efforts that incorporate students sharing
their experiences with each other allow task-oriented
learners to dissect a learning task and tentative students to discuss their experiences.
Table 8
Subscale Differences Among Groups of
Learning Styles
Subscale
Implications for Practice
There are practical implications for students, clinical instructors and technologists involved with students
during clinical practice. Findings suggest radiography
students would achieve more if they were able to ask
questions before, during and after a learning experience, as well as create a plan of action and recognize
the sequence of tasks. Clinical faculty and technologists
could aid in the learning process by being available to
answer questions, prompting students to determine
a strategy before beginning a task and helping apply
theoretical concepts to clinical practices.
Students who identified with the task-oriented learning style were absorbed in learning tasks and trusted
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
Structure
Learning Style
Taskoriented
Purposeful
Tentative
Ma
Hb
Lc
Integration
L
H
L
Experimentation
H
M
L
Authority
L
L
H
Orientation
L
H
L
Approach
H
L
M
a
M = mid
b
H = high
c
L = low
535
...........................................................................................................
CLINICAL LEARNING STYLES
This study showed that radiography students in general integrate theory and practice, and that students who
identified with the purposeful learning style are significantly more likely to do so. Planning and focusing on
results correlated with integration of theory and practice.
These findings suggest that educational interventions
that encourage planning and focus on desired results
and use of theory as a guide may improve the integration of foundational knowledge taught in the classroom
with skills learned during clinical practice. To facilitate
planning, students from each learning style group could
benefit from the use of pocket handbooks, checklists and
other materials before becoming directly involved in a
task. The availability of clinical instructors or technologists to answer questions also is part of planning.
Recommendations for clinical instructors of students who identified with the tentative learning style
are to provide clearly written policies, including expectations, assessment criteria and timelines, to facilitate
learning for these students. The data demonstrated
tentative learners depended on expert opinion more
than other learning style groups. It is important for
clinical instructors or other clinical faculty to be available to provide the support necessary to maximize
learning opportunities for these students. Clinical
faculty can provide more informal prompting to help
students apply theoretical basis to clinical practices.
Knowledge of clinical practice learning styles can
serve as a springboard for enhancing learning opportunities to improve teaching effectiveness and student
achievement. For example, clinical instructors and technologists can help students understand how to integrate
theory and practice. Students can be encouraged to
reflect on prior experiences, relate theoretical principles
to clinical situations and relate clinical experiences to
theoretical principles. Prompted journaling can teach
students how to reflect on experiences and relate them
to knowledge they have gained in the classroom. Clinical
instructors and technologists can encourage students to
recall and explain theoretical principles when evaluating
patient care experiences, images or imaging procedures.
Conclusion
This study presents valuable information regarding
learning styles of radiography students during clinical
practice and provides a useful platform for students,
clinical instructors and technologists to discuss learning behavior in the context of the clinical practice
setting. An awareness of learning styles used during
536
clinical practice can enhance student success and
teacher efficacy.
References
1. American Registry of Radiologic Technologists. Appendix
C: radiography didactic and clinical competency requirements. 2008 Certification Handbook for Radiography. St Paul,
MN: American Registry of Radiologic Technologists;
2007:31-35.
2. Fortsch P. How the Clinical Settings of Radiography Programs
Affect Learning Perceptions [dissertation]. Cedar Falls, IA:
University of Northern Iowa; 2007:212.
3. Dunn R. Bibliography of research. New York: St. John’s
University’s Center for the Study of Learning and
Teaching Styles. www.learningstyles.net. Accessed July 8,
2008.
4. Gregorc AF. An Adult’s Guide to Style. Columbia, CT:
Gregorc Associates; 1982.
5. Kolb AY, Kolb DA. Experiential learning theory bibliography: Volume 1, 1971-2005. Experience Based Learning
Systems website. www.learningfromexperience.com
/research-library. Accessed May 23, 2008.
6. Kolb AY, Kolb DA. Experiential learning theory bibliography: Volume 2, 2006-2008. Experience Based Learning
Systems website. www.learningfromexperience.com
/research-library. Accessed May 23, 2008.
7. Witkin HA, Moore CA, Goodenough DR, Cox PW. Fielddependent and field-independent cognitive styles and their
educational implications. Rev Educ Res. 1977;47(1):1-64.
8. Hermanussen J, Wierstra RF, de Jong JA, Thijssen JG.
Learning styles in vocational work experience. J Vocat Edu
Res. 2000;25(4):445-471.
9. Coffield F, Moseley D, Hall E, Ecclestone K. Learning
styles and pedagogy in post-16 learning: a systematic and
critical review. www.crm.lsnlearning.org.uk/user/order
.aspx?code=041543. Accessed July 23, 2008.
10. Curry L. An organization of learning styles theory
and constructs. Paper presented at: 67th American
Educational Research Association Annual Meeting; April
1983; Montreal, Quebec. ED235185.
11. Miller A. Cognitive styles: an integrated model. Educ
Psychol. 1987;7(4):251-268.
12. Riding R, Cheema I. Cognitive styles — an overview and
integration. Educ Psychol. 1991;11(3/4):193-216.
13. Sadler-Smith E. Learning style: frameworks and instruments. Educ Psychol. 1997;17(1/2):51-64.
14. Zhang LF, Sternberg R J. A threefold model of intellectual
styles. Educ Psychol Rev. 2005;17(1):1-53.
15. Dunn R, Dunn K. Teaching Students Through Their
Individual Learning Styles: a Practical Approach. Reston, VA:
Prentice Hall; 1978.
16. Kolb DA. Experiential Learning: Experience as the Source of
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
...........................................................................................................
WARD, MAKELA
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
Learning and Development. Upper Saddle River, NJ: Prentice
Hall; 1984:38.
Davis L. The Effects of Learning Style on Academic Achievement
in an Allied Health Radiography Program [dissertation].
Houston, TX: University of Houston; 2001.
Shaver VE. Learning Styles and Student Success in Radiography
Education [dissertation]. Boca Raton, FL: Florida Atlantic
University; 2000.
Wright DL. Radiography Student Learning Style Preferences
and Computer Readiness [dissertation]. Raleigh, NC: North
Carolina University; 1998.
Fowler P. Learning styles of radiographers. Radiography.
2002;8(1):3-11.
Cavanagh SJ, Hogan K, Ramgopal T. The assessment of
student nurse learning styles using the Kolb learning styles
inventory. Nurs Educ Today. 1995;15(3):177–183.
DeCoux VM. Kolb’s learning style inventory: a review
of its applications in nursing research. J Nurs Educ.
1990;29(5):202–207.
Hauer P, Straub C, Wolf S. Learning styles of allied
health students using Kolb’s LSI-IIa. J Allied Health.
2005;34(3):177-182.
Hodges S. Individual learning styles of student
nurses, their teachers, and ward sisters. J Adv Nurs.
1988;13(3):341-344.
Katz N, Heimann N. Learning style of students and practitioners in five health professions. Occupational Therapy
Journal of Research. 1991;11(4):238-244.
Laschinger HK, Boss MW. Learning styles of nursing students and career choices. J Adv Nurs. 1984;9(4):375-380.
Suliman WA. Critical thinking and learning styles of students in conventional and accelerated programmes. Int
Nurs Rev. 2006;53(1):73-79.
Polit DF, Beck CT. Nursing Research: Generating and Assessing
Evidence for Nursing Practice. 8th ed. Philadelphia, PA:
Lippincott Williams & Wilkins; 2008.
Ward LP. Learning Styles of Radiography Students During
Clinical Practice [dissertation]. Ft Collins, CO: Colorado
State University; 2009.
Patti Ward, PhD, R.T.(R), is a professor and clinical coordinator for the radiologic technology program at Mesa State
College in Grand Junction, Colorado. Carole Makela, PhD,
is a professor in the School of Education at Colorado State
University in Ft Collins, Colorado.
Reprint requests may be sent to the American Society of
Radiologic Technologists, Communications Department,
15000 Central Ave SE, Albuquerque, NM 87123-3909, or
e-mail [email protected].
©2010 by the American Society of Radiologic Technologists.
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
537
. . . . . . . . . . . . . . . . . . . . . . . . ...........................................................................
PEER REVIEW
Factors Related to Radiation
Safety Practices in California
JANET THOMPSON REAGAN, PhD
ANITA MARIE SLECHTA, MS, R.T.(R)(M), FASRT
Background A national study of radiologic technologists’ radiation safety practices in 2003 documented poor compliance. In addition,
the 2003 study found that years of work experience and length of employment at a work site were significantly related to adherence with
safety practices. The current study is a refinement and extension of the 2003 study.
Purpose To determine the degree of compliance with personnel radiation safety practices and patient radiation safety practices as
correlated with initial professional education, highest level of education, years of employment in the radiologic sciences and type of
work site.
Method A 33-item questionnaire was mailed to a random sample of 1500 California radiologic technologists certified by the American
Registry of Radiologic Technologists. The return rate was 32%.
Results Mean scores were 77.1% for compliance with patient safety practices and 70.5% for compliance with personnel safety practices.
Performance on individual items ranged from 95.6% to 27.4% compliance. Two independent variables, years of employment in the radiologic sciences and work site, were significantly related to adherence with safety practices (P < .05).
Conclusion The results of this study corroborated those of the national study and indicated the need for educational and organizational
interventions to increase compliance with safety practices for patients and personnel.
A
national study of factors related to radiologic technologists’ knowledge of and
compliance with radiation safety practices documented poor compliance.1 The
study found that 2 independent variables
— years in practice as a radiologic technologist and
length of employment at the work site — were significantly related to safety practices. Compliance with safety practices was higher in large hospitals and, as years
of practice increased, initial compliance increased and
then later declined.
Contrary to the researchers’ expectations, the type
of initial education was not significantly related to compliance with safety practices. Although the study did
not intend to investigate differences between personnel
safety practices and patient safety practices, an examination of performance on individual items revealed
consistently better compliance with patient safety practices than with personnel safety practices.
Literature Review
Because compliance with safety practices was consistently lower for personnel safety than patient safety,
an extensive review of the literature on health risks
538
to the radiologic technologist due to long-term occupational exposure to low-dose ionizing radiation was
conducted. Of the articles identified, most were reports
of research conducted using the data generated by the
U.S. Radiologic Technologists Study initiated in 1982.
Several articles2-4 provide an overview of the purpose
and methods of this study.
Early studies found cumulative exposure to ionizing
radiation increased with length of employment,2 but
the risk of breast cancer was not related to length of
employment as a radiologic technologist.3 Although the
results of later studies were mixed and often difficult to
interpret, they identified health risks to radiologic technologists and some challenged current assumptions
regarding safe levels of exposure.5
Results of a study published in 2002 showed an
increased risk for breast cancer for technologists
employed prior to 1950.4 A 2003 article reported an
increased risk for solid tumors, breast cancer and
thyroid cancers for female technologists, and an
increased risk for melanoma and thyroid cancer in
male technologists. For both sexes, the risks of certain
other cancers (eg, lung cancer) were less than would
be expected,6 complicating the interpretation of the
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
...........................................................................................................
REAGAN, SLECHTA
findings. Increased risks for nonmelanoma skin cancer7
and cataracts also have been found.5 Although results
are not always consistent, research in general supports
the need to establish and observe safety practices to
minimize the exposure of radiologic technologists.
No recent articles on methods of improving compliance with personnel safety practices were found. Most
literature focuses on compliance with patient safety
practices, which are of primary concern for radiologic
technologists. Compliance with patient safety for
diagnostic radiography, computed tomography (CT)
and mammography, the primary focus of this study, is
rarely addressed in the literature. Notable exceptions
are the 2007 review of the literature on patient dose
from CT and the 2006 review of radiation protection practices.8,9 The focus of these reviews was the
increased use of CT and the actual procedural patient
dose, documentation of the patient dose and pediatric
procedural dose adjustments. No literature other than
the national study1 focused on either patient or personnel radiation protection practices in a broader sense.
Study Objectives, Variables and
Limitations
The current study had 2 primary objectives:
■ To ascertain whether key findings of the national
study would be replicated with a revised instrument and with the California-based population
of American Registry of Radiologic Technologists
(ARRT) registrants.
■ To determine whether there was a significant difference between compliance with personnel safety practices and compliance with patient safety
practices.
In the national study, the 2 dependent variables were
knowledge of safety practices and compliance with safety
practices. Knowledge of safety practices was higher
(82%) than compliance (72%), and there was a significant, positive correlation between them. Although knowledge is not unimportant, for this study the focus was on
compliance and whether the level of compliance was
different for personnel safety vs patient safety. Thus, the 2
dependent variables were compliance with patient safety
practices and compliance with personnel safety practices.
The independent variables in the national study
were initial education, years in practice, participation
in continuing education (CE) and type of work site.
Almost all (98.9%) of the respondents in the national
study had completed CE in the past year. Thus the
relationship between CE and the dependent variables
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
could not be examined. For this study, participation
in CE was dropped from the independent variables
and highest level of education was added. The 4 independent variables were initial education, highest level
of education, years in practice and type of work site.
Based on the previous study, the following predictions
were made: compliance with patient safety practices
would be significantly higher than compliance with
personnel safety practices; compliance with personnel
and patient safety practices would be correlated with
type of work site and years in practice; compliance with
personnel and patient safety practices would not be correlated with type of initial education; and compliance
with personnel and patient safety practices would be
correlated with highest level of education.
The assumptions underlying the study were as follows:
■ Respondents would give accurate responses
regarding safety practices.
■ Any bias in responses would result in an overestimate of compliance.
■ The questionnaire provides a valid assessment of
compliance with patient safety practices and personnel safety practices.
■ The predicted results are reasonable based on
the results reported in the Tilson,10 Lemley11 and
Slechta and Reagan1 studies.
The limitations of the study are the following:
■ Although the 32% return rate is not uncommon
for a mailed survey, it limits the ability to generalize the results to the population sampled, even
though the characteristics of the respondents
were similar to those of the population of ARRT
registrants in terms of sex distribution, years
of practice as an ARRT registrant and site of
employment.
■ The questionnaire was a revised, refined version
of an instrument used in a previous study.
■ Experts in the field reviewed the instrument for
relevancy to the field of practice and content
validity. However, test-retest reliability has not
been established.
■ Respondents were asked to indicate their primary
area of practice and instructed to complete items
pertaining to their own activities. Results indicated that many respondents engaged in activities outside their primary area of practice. For
example, 62 respondents indicated their primary
area of practice as CT, yet the number responding to the items assessing compliance with CT
safety practices ranged from 152 for item 17 to
539
...........................................................................................................
RADIATION SAFETY PRACTICES
Table 1
Study Design
Personnel
Radiation
Protection
11 Questions
Portable/
Mobile
Radiography
Fluoroscopy
Questions No.
6, 7, 8
Questions No.
9, 10, 11, 12, 13
Patient
Radiation
Protection
15 questions
Total Number
of Questions
CT
General
Radiography
Questions No.
20, 21, 22
Question No. 14
Questions No.
15, 16, 17
Questions No.
18, 19, 23, 24,
25, 26, 27, 28,
29, 30, 31
6
3
14
3
Table 2
Summary Statistics for Dependent Variables
95% Confidence Interval of Mean
Dependent
Variable
n
Mean
Standard
Deviation
Standard
Error of Mean
Personnel
Safety
317
70.5
17.6
.99
Patient
Safety
420
77.1
13.1
.64
170 for item 15, indicating that many ARRT registrants engage in CT activities even though CT is
not their primary area of practice. Therefore, one
cannot draw conclusions about the compliance
with safety practices by individuals whose primary
area of practice is CT by reviewing performance
on the CT items.
Methods
A survey of 1500 ARRT- certified radiologic technologists in California was conducted. Questionnaires were
mailed September 19, 2005, with a requested return date
of October 21, 2005. All responses were anonymous.
Sample Design
The sample frame was the database of the ARRT,
which supplied a simple random sample and summary
data on the characteristics of the California registrants. Registrants who had advanced certification in
magnetic resonance (MR) imaging, radiation therapy
540
Lower
Boundary
and ultrasound were
excluded from the
sampling frame.
A sample of 1500
was drawn from the
study population
of 7301 because
response rates to
mailed surveys are
usually low. With
an estimated 20%
response rate (based
on the return rate of
the previous study), a
sample of 1500 would
yield 300 responses,
sufficient for a 95%
confidence level with
a 6% margin of error
and, therefore, sufficient for the planned
statistical analyses.12
Upper
Boundary
Questionnaire Design
The question68.6
72.4
naire was a modified version of the
76.5
77.7
questionnaire used
in the national
study.1 Response
categories to items soliciting demographic information were modified to match those used by the ARRT.
This allowed for a better comparison of respondent
demographic characteristics with those of the ARRT
registrants than was possible in the national study.
In addition, because this study examined compliance
with personnel safety practices and patient safety practices separately and did not examine knowledge of
safety practices, all items assessing knowledge of safety
practices were excluded from the questionnaire and
the number of items assessing compliance with safety
practices was increased to ensure content validity.
The resulting 33-item instrument solicited basic
demographic information, information on the 4
dependent variables (ie, type of initial professional
education, highest level of education, years in professional practice and type of work site) and information on the 2 dependent variables (ie, compliance
with personnel safety practices and compliance with
patient safety practices) (see Tables 1, 2 and 3). Of
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
...........................................................................................................
REAGAN, SLECHTA
the 33 items, 7 solicitTable 3
ed information about
Study Analysis
respondent characteristics, including
Independent Variables
Dependent Variables
sex, age, years in
Personnel Safety Practice Patient Safety Practice
practice, primary
Initial radiologic science education
Spearman = .053
Spearman = −.025
area of practice, work
Kendal = −.021
Kendal = .042
site, initial radiologic
technology education
Highest level of education
Spearman = −.038
Spearman = −.006
Kendal = −.030
Kendal = −.002
and highest level of
a
education (see Tables
Years as a radiologic technologist
Spearman = −.05
Spearman = −.130
4 and 5). Compliance
Kendal = −.077
Kendal = −.088a
with patient safety
b
Primary work site
Spearman =.100
Spearman = .114
practices was assessed
a
Kendal = .073
Kendal
=
.084
through 15 items
a
Significant at P < .05.
and compliance with
b
Spearman .114 is a weak correlation but P < .05 means we have confidence in this finding and it is
personnel safety
not likely due to chance.
practices was assessed
through 11 items (see
and scopes of practice. When the highest possible
Tables 6-14). Survey questions focused on portable/
score for a respondent was less than 11 for personnel
mobile imaging (3 questions), fluoroscopy (6 items),
safety or less than 19 for patient safety, no compliance
CT (3 items) and general radiography (14 items) (see
score was calculated. Even though the N for this study
Table 1).
was 431, the n for patient safety was 420 and the n for
personnel safety was 317. The number of responses to
Data Analysis
individual items ranged from a low of 131 for item 13
Scoring guides were developed for calculating the
to a high of 412 for item 16. Data were analyzed using
scores for compliance with personnel and patient safeSPSS (SPSS Inc, Chicago, Illinois) to provide descripty practices. The highest possible score was 22 for pertive statistics and tests for associations among the
sonnel safety and 37 for patient safety. Not all respondependent and independent variables.
dents completed all items because of different areas
Table 4
Initial Radiologic Technology Education and Compliance With Radiation Safety Practice
California Study
(N = 431)
Initial R.T. Education
Personnel Safety
National
(N = 451)
Patient Safety
Combined Personnel
and Patient Safety
Mean
SDa
Mean
SD
Mean
SD
Hospital-based program/certificate
program
69.1
19.6
76.4
11.7
74.3
23.2
Associate degree
71.8
16.8
77.7
13.4
71.6
22.9
Bachelor’s degree in radiologic
technology/science
66.3
17.7
78.8
12.6
69.9
29.1
Military program
64.5
17.4
74.9
15.6
70.2
17.1
Other
81.8
54.5
NA
64.0
29.0
a
Standard deviation
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
541
...........................................................................................................
RADIATION SAFETY PRACTICES
work history; 46.1%
had been in practice for 16 or more
California Study
years. The primary
area of practice for
Highest Education
Personnel Safety
Patient Safety
most respondents
(n = 317)
(n = 385)
was diagnostic/
a
a
Mean
SD
Mean
SD
general (67%), folHospital-based program/certificate program
71.0
19.3
77.2
10.6
lowed by CT (14.4%)
and mammograAssociate degree
70.8
17.0
77.5
13.5
phy (11.1%). Most
Bachelor’s degree
68.8
18.8
76.1
14.9
respondents worked
Master’s degree
75.1
2.8
71.9
5.1
in hospitals (64%),
followed by clinics
Other
74.8
21.6
72.6
8.9
(20.9%). Of those
a
Standard deviation
working in hospitals
(n = 276), 16.3% were
Results
in small hospitals (1 to 99 beds), 48.6% were in mediOf the 1500 questionnaires, 480 were returned for a
um hospitals (100 to 299 beds) and 35.1% were in large
response rate of 32%, which was higher than the anticihospitals (300 or more beds). Sex distribution, average
pated return rate of 20%. Only 431 questionnaires
years of practice as an ARRT registrant and place of
(28.7%) were usable for analysis; 49 were excluded
employment were similar for the respondents and the
because of insufficient responses.
California ARRT registrant population.
Most of the respondents received their initial
Characteristics of Respondents
radiologic technology education through associate
Forty-nine percent of the respondents were women
degree programs (61.7%) or hospital-based certificate
and 41% were men. Most respondents had a long
programs (28.8%). Few had completed bachelor’s programs (3%), military programs (6.3%) or other types
Table 6
of programs (0.2%). For most respondents, the highest
Table 5
Highest Level of Education and Compliance with Radiation Safety Practice
Personnel Radiation Safety Practice Questions
6. When performing portable exams, how often do
you wear a lead apron if you cannot stand 6 feet
from the patient?
Table 7
Personnel Radiation Safety Practice Questions
(Continued)
n = 319
60.2
8. How often do you hold patients during portable
radiography?
Sometimes
29.8
California Study
Never
10.0
n = 284
Always
a
%
7. When setting up a C-arm procedure and when
room size and patient bed allows, how often do
you place the x-ray tube above the image intensifier tube for the procedure?
n = 248
%
Alwaysa
27.4
Sometimes
45.2
Never
27.4
a
Best practice
542
National Study Comparable
%
n = 318
%
Daily
4.7
Once a
week
22.3
27.0
28.2 Once a
month
24.5
24.5
Once a
year
26.7
At least once a week 17.6
At least once a
month
Once a year or lessa 54.2 Never
21.7
%
48.5
a
Best practice
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
...........................................................................................................
REAGAN, SLECHTA
Table 8
Personnel Radiation Safety Practice Questions
(Continued)
Table 9
Personnel Radiation Safety Practice Questions
(Continued)
9. Where do you stand during a typical upper GI
fluoroscopic procedure?
11. Where do you wear your personnel
monitoring device?
California Study (n = 315)
%
California Study
(n = 284)
By the patient’s head
Behind the doctor
a
In the control room
a
At the foot of the table
%
National Study
(n = 264)
%
At waist level outside apron
88.3
5.6
10.6
At collar level outside apron
75.1
70.4
At collar level inside apron
9.5
15.4
11.7
Other
1.9
3.9
2.6
Other
NA
4.5
10. Where do you stand during a typical lower GI
fluoroscopic procedure?
%
California Study
%
National Study
By the patient’s head
0.3
a
0.4
3.4
Behind the doctor a
68.7
61.7
In the control rooma
11.6
7.6
At the foot of the table
19.4
22.4
Other
NA
5.3
12. During a fluoroscopic procedure, how often do
you wear a thyroid shield?
National Study %
California Study
%
(n = 270)
(n = 301)
Alwaysa
49.8
Sometimes
33.6
37.4
Never
16.6
28.5
34.1
a
Best practice
level of education was an associate degree (59.6%) or
certificate program (19.5%). A bachelor’s degree was
held by 18.3%, followed by 2.4 % with a master’s or
higher degree.
Compliance With Personnel and Patient Safety Practices
Compliance with safety practices was evaluated by
calculating 2 scores, one for personnel safety practices
and one for patient safety practices. The mean score for
personnel safety practice (N = 317) was 70.5% with a SD
of 17.6; the mean score for patient safety practice (N =
385) was 77.1% with a SD of 13.1. With 95% confidence,
the mean for personnel safety falls between 68.6% and
72.4%. The mean for patient safety falls between 76.5%
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
13. How often do you hold patients during
fluoroscopic procedures?
California Study (n = 273)
%
At least once a week
6.6
At least once a month
In the control room
a
Once a year or less
26.0
11.6
a
67.4
a
Best practice
and 77.7% (see Table 2). The 2 means are significantly
different, t = 5.60, P < .005, two-tailed test. Although the
distributions for the compliance scores were skewed to
the right, the skewness value was within the acceptable
range of ±2. Because the distributions of the compliance
scores were not normal, the relationship between them
was evaluated using Kendall rank correlation and
Spearman correlation. For both tests, the relationship
between the scores was weak, positive and significant: =
.172, P < .01 level, and = .251,
P < .01, indicating that respondents who complied with
patient safety practices were only slightly more likely to
comply with personnel safety practices.
Relationships Among Independent and Dependent Variables
Relationships among independent and dependent
variables were tested using Spearman rank correlation () and Kendal rank correlation for categorical
variables (see Table 3). A weak, positive relationship
was found for primary work site and personnel safety
practices ( = .114, P < .05), and a weak, negative relationship was found for years in practice and personnel safety practices ( = .100, P < .05). No significant
relationships were found between initial education and
compliance or highest level of education and compliance (see Tables 3, 4 and 5).
543
...........................................................................................................
RADIATION SAFETY PRACTICES
Table 10
Personnel Radiation Safety Practice Questions
(Continued)
California
Study Only
At least
At least
Once a
once a
once a
year or
week (%) month (%) lessa (%)
20. How often do you hold adult patients during
routine radiography?
360
10.3
22.5
67.2
n
21. How often do you hold pediatric patients during
routine radiography?
356
15.4
32.3
52.2
22. How often do you hold patients during trauma
radiography?
386
8.4
30.4
61.2
a
Best practice
Although both the California and the national
studies found a significant relationship between the
type of work site and compliance with safety practices, the site with best practice was different in the 2
studies (see Table 4). For the national study, compliance was highest in large hospitals; for the California
study, compliance was highest for outpatient facilities,
imaging centers and private offices. Although the
absolute difference was not great in either study, it was
a significant difference (P < .05) and not likely due
to chance. For the California study, compliance with
safety practices declined with years in practice and the
decline in the mean compliance score was greater for
personnel safety (6.6 points) than for patient safety
(3.6 points). This difference was weak and significant
for personnel safety, = −.130 and P < .05, weak and
not significant for patient safety (see Table 3). For the
national study, there was a curvilinear relationship:
Initial compliance was low (68%), then increased to
76% compliance by 16 to 25 years and then declined
to 73% after 26 years.
Scores on individual items ranged from a high of
95.6% best practice on question 25 (see Table 13), to
a low of 27.4% best practice for question 7 (see Table
6). ARRT registrants in the California study scored
consistently higher than those in the national study —
from 3.1% to 21.9% higher on the 8 items common to
both studies (see Tables 7, 8 and 11). Using 85% best
practice (in educational terminology a grade of “B”) as
544
the desired level of performance, ARRT registrants met
the standard for best practice on only 6 of the 26 items.
Clearly, compliance levels should be higher to protect
the technologist and patient.
Conclusion and Recommendations
The results of this study corroborate some of the
findings of the national study and support the predictions that compliance would be higher for patient
safety practices than for personnel safety practices, and
that years in practice and type of work site would be
related to safety compliance. This study, in combination
with the national study, has increased our understanding of knowledge of and compliance with radiologic
safety practices and has raised several questions that
merit additional research.
Major findings from the national and the current
study are as follows:
National
■ Participation in CE was high, 98.9%, yet compliance with safety practices was low, 72.2%.
■ Knowledge of safety practices was higher than
compliance with safety practices, 82.2% and
72.2%, respectively.
National and California Study
■ Compliance was higher for patient safety practices than for personnel safety practices,
77.1% and 70.5%, respectively. Although compliance may have increased since the current
study was completed, there was no notable
improvement in compliance scores in the 3
years between the national study and the current study.
■ Type of initial education and highest level of
education were not related to level of
compliance.
■ The relationships between type of work site
and years in practice to compliance are complex and inconsistent.
Additional research is needed to address the
following questions:
■ Considering that CE is required and there is
almost universal participation, why is compliance with safety practices low? Areas for investigation include topics covered in CE, methods
most often employed (eg, Directed Readings,
conferences, etc) and the incentives or disincentives for transferring learning to practice.
■ Why is compliance with safety practices greater for patients than for personnel? With poor
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
...........................................................................................................
REAGAN, SLECHTA
Table 11
Patient Radiation Safety Practice Questions
(Continued)
Table 12
Patient Radiation Safety Practice Questions
(Continued)
14. During fluoroscopy with an under-the-table x-ray
tube, where do you place the image intensifier?
17. How often do you alter the manufacturer’s
recommended technique (mA & kVp) for a chest
or abdomen CT when you are imaging a pediatric
patient?
California Study
(n = 212)
%
As far away from the
patient as possible
6.8
15.3
91.9
80.9
As close to the
patient as possiblea
The distance or position does not matter
National Study
(n = 130)
%
0.0
3.8
%
National Study
( n = 136)
%
Alwaysa
47.4
Sometimes
37.5
Never
13.2
19. For which of the following patients would you use
gonadal shielding for a foot x-ray?
15. Do you use gonadal shielding on a woman of
child-bearing age during a CT of the chest?
California Study
(n = 170)
California Study Only
(n = 152)
California Study Only
(n= 431)
%
%
2-day-old baby
95.4
Always
45.9
40.4
15-year-old girl
94.9
Sometimes
27.6
36.8
85-year-old man
18.3
Never
26.5
22.8
50-year-old man
52.2
33-year-old man
86.3
24-year-old woman
95.1
7-year-old girl
96.3
16. Where do you place gonadal shielding during a
CT exam of the chest?
California Study
(n = 168)
%
On top of the patient
11.3
9.2
Around the entire
pelvisa
67.3
70.4
Under the patient
0.6
2.1
20.8
18.3
No gonadal shielding
is necessary
National Study
(n = 142)
%
18. Have you compared radiation from the sun to
radiation from diagnostic x-rays when talking to
patients who are nervous about the dose for their
diagnostic procedure?
California Study
(n = 426)
%
National Study
(n = 413)
%
Always
20.0
9.9
Sometimes
62.0
50.1
Nevera
18.1
40.0
a
Best practice
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
24. How have you attempted to decrease your
patient’s dose in the last year? (Select all that
apply.)
California Study Only
(n = 431)
%
Decrease mAs
65.9
Use lead shielding
85.2
Increase kVp
62.9
Unable to manipulate dose
3.7
a
Best practice
safety practice, both will be at risk for unnecessary exposure to radiation. Yet, the risk for
excessive exposure may be greater for staff,
considering they may have 20- to 30-year
careers.
■ What can be done to increase compliance
with safety practice? A multipronged approach
involving professional associations and health
care organizations is required.
545
...........................................................................................................
RADIATION SAFETY PRACTICES
Table 13
Patient Radiation Safety Practice Questions
(Continued)
California
Study Only
n
Alwaysa
%
Sometimes
%
Never
%
Table 14
Summary of Poor Personnel Radiation Safety
Practicea — California Study Only
Question No.
6. (apron usage)
60.2
7. (C-arm/II position)
27.4
8. (hold patient for portable)
54.2
10. (where R.T. stands for BE)
80.3
12. (wear thyroid shield)
49.8
13. (hold patient for fluoro)
67.4
20. (hold patient for radiography)
67.2
21. (hold pediatric patient)
52.2
22. (hold trauma patient)
61.2
25. How often do you ask females that are in their
reproductive years if they are pregnant before
diagnostic exams?
427
95.6
4.2
0.2
26. How often do you use gonadal shielding on a
3-year-old boy who needs a chest x-ray?
395
92.4
6.3
1.3
How often do you use gonadal shielding on a
__________ who needs a __________ x-ray?
n
Always
%
Sometimes
%
Never
%
27. 16-year-old boy/L-spine
395
92.4
6.3
62.3
26
1.3
28. 37-year-old man/knee
408
407
84.3
11.1
4.7
39.8
28.5
31.8
31. 19-year-old man/esophagram
322
61.8
18.6
19.6
a
Best practice
■ What impact will changing technology have
on risk of and levels of unnecessary exposure
for patients and personnel? Future research
on radiation protection practices will not only
have to focus on personnel and patient safety,
but will need to address new technologies such
as digital radiography and CT that have the
potential to increase patient dose.13,14,15 Because
the majority of technologists using these newer
technologies were educated initially in analog
technology, they may not understand how best
to decrease patient dose using digital radiography and CT systems.
Because radiation protection practice was consistently poor in both the national and California studies, we
546
Defined as less than 85%.
Summary of Poor Patient Radiation Safety
Practicea — California Study Only
Question No.
30. 10-year-old boy/pelvis
400
a
11.8
29. 21-year-old woman/finger
% Best
Practice
% Best
Practice
15. Gonad shield on CT female
45.9
16. Location of gonad shield CT female
67.3
17. Vary technique on pediatric CT
47.4
18. Compare sunlight to x-ray
18.1
24. Decrease dose with technique
(mAs, kVp)
65.9,
62.9
28. Shield 37-year-old male knee
62.3
30. Shield 10-year-old male pelvis
39.8
31. Shield 19-year-old male
esophagram
61.8
a
Defined as less than 85%.
need to evaluate current CE practices as remediation
for these poor practices. These are most timely questions, since the ARRT is considering different systems
of recertification for individuals certified after 2011.
Will the recertification system address the poor radiation protection practices identified in these research
projects? Radiation protection practice for both
patients and personnel is fundamental to every aspect
of the radiologic technologist’s role. Further research
may identify how to improve protection practices.
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
...........................................................................................................
REAGAN, SLECHTA
References
1. Slechta AM, Reagan JT. An examination of factors
related to radiation protection practices. Radiol Technol.
2008;79(4):297-305.
2. Boice JD Jr, Mandel JS, Doody MM, Yoder CY, McGowan
R. A health survey of radiologic technologists. Cancer.
1992;69(2):586-598.
3. Boice JD Jr, Mandel JS, Doody MM. Breast cancer among
radiologic technologists. JAMA. 1995:274(5):394-401.
4. Mohan AK, Hauptman M, Freedman DM, et al. Cancer
and other causes of mortality among radiologic technologists in the United States. Int J Cancer. 2003;103(2):
259-267.
5. Chodick G, Bekirogiu N, Hauptmann M, et al. Risk of
cataract after exposure to low doses of ionizing radiation:
a 20-year prospective cohort study among US radiologic
technologists. Am J Epidemiol. 2008;168(6):620-631.
6. Sigurdson AJ, Doody MM, Roa RS, et al. Cancer incidence in the US radiologic technologists. Cancer.
2003;97(12):3080-3089.
7. Yoshinaga S, Hauptmann M, Sigurdson AJ, et al.
Nonmelanoma skin cancer in relation to ionizing radiation exposure among US radiologic technologists. Int J
Cancer. 2005;115(5):828-834.
8. Colang JE, Killion JB, Vano E. Patient dose from CT: a literature review. Radiol Technol. 2007;79(1):17-26.
9. Engel-Hills P. Radiation protection in medical imaging.
Radiography. 2006;12(2):153-160.
10. Tilson E. Educational and experiential effects on
radiographers’ radiation safety behavior. Radiol Technol.
1982;53(4):321-325.
11. Lemley AA, Hedl JJ Jr, Griffin EE. A study of radiation
safety education practices in acute care Texas hospitals.
Radiol Technol. 1987;58(4):323-331.
12. Shi L. Sampling in health services research. In: Health
Services Research Methods. Albany, NY: Delmar Publishers.
1997;226-242.
13. Bushong S. Digital radiography. In: Bushong S. Radiologic
Science for Technologists. 8th ed. St. Louis, MO: Elsevier.
2004;403.
14. Compagnone G, Casadio Baleni M, Pagen L. Comparison
of radiation doses to patients undergoing standard
radiographic examinations with conventional screen-film
radiography, computed radiography and direct digital
radiography. Br J Radiol. 2006(79):899-904.
15. Neofotistou V, Isapaki V, Kottou S, et al. Does digital imaging decrease patient dose? A pilot study and review of the
literature. Radiat Prot Dosimetry. 2005;117(1-3):204-210.
of the graduate health administration program. She has served
as chairman of the board of directors of the Association of
University Programs in Health Administration, as well as chairman of the Committee on Education of the American College of
Healthcare Executives. Her research interests and publications
are primarily in the areas of human resource management and
quality improvement.
Anita Slechta, MS, R.T.(R)(M), FASRT, is a full professor
of health science at California State University, Northridge,
and program director of the bachelor’s degree program in
radiologic technology. She served as chairman of the ASRT’s
Task Force on Baccalaureate Curriculum, was a delegate for
ASRT’s Education Chapter and has been chairman of the
ASRT Commission on Education. Her interests include licensure and education, with the purpose of protecting the public
from unnecessary radiation.
The authors wish to acknowledge the Department of Health
Sciences at California State University, Northridge, for providing support for this research.
Reprint requests may be sent to the American Society of
Radiologic Technologists, Communications Department,
15000 Central Ave SE, Albuquerque, NM 87123-3909, or
e-mail [email protected].
©2010 by the American Society of Radiologic Technologists.
Janet T Reagan, PhD, is a full professor of health administration at California State University, Northridge, and director
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
547
..CE
. . . . . . . . . . . . . . . . . . . . . . . . . . .......................................................................
DIRECTED READING
Bleeding Risks in
Interventional Radiology
AMY MORRIS, AA, R.T.(R)
Bleeding complications are
a concern for patients who
have interventional radiology
procedures. This article discusses reasons for abnormal
coagulation, conditions that
increase patients’ risk for
bleeding from interventional
procedures, coagulation
parameters and common
methods to modify the hemostatic system.
This article is a Directed
Reading. Your access to
Directed Reading quizzes for
continuing education credit
is determined by your area of
interest. For access to other
quizzes, go to www.asrt.org
/store.
548
After completing this article, readers should be able to:
■ List some hereditary and acquired conditions that cause coagulation disorders.
■ Discuss the laboratory studies and parameters used to assess coagulation.
■ Describe how anticoagulant and antiplatelet medications are used and the problems they can cause
for patients having invasive procedures.
■ Understand the need to consider risks vs benefits for patients on anticoagulation therapy who need
interventional procedures.
■ List the methods used for modifying overanticoagulation.
A
s interventional radiology
procedures have become
more complex, so too have
the needs of patients who
undergo these procedures,
including millions who receive anticoagulant therapy to prevent or treat thromboembolism. These medications are
associated with a risk of bleeding and,
along with antiplatelet agents, can complicate management of patients in the
interventional radiology suite.1,2
Blood coagulation and physiologic
hemostasis are complex processes that
are meant to defend the circulatory system.3 When something goes wrong with
hemostasis, either because of a disease
or condition, or as a side effect of medication, the normal defense mechanism
is altered and the patient can bleed
severely. The key to preventing severe
bleeding from interventional procedures is periprocedural management.4
Managing these patients requires
understanding clinical laboratory values
and their significance for postprocedure
bleeding, the reasons why lab values are
abnormal and the methods that may be
used to bring them back into acceptable range to help minimize a patient’s
bleeding risk.
Blood Coagulation
Coagulation begins at the cellular
level. When endothelial cells are damaged, protein factors in membranes
are exposed that trigger the coagulation process, which activates platelets,
the cells primarily involved. 5,6 The
platelets, endothelial cells and proteins
involved in coagulation make up the
hemostatic system. 3
The blood coagulation cascade that
begins with injury to the closed circulatory system may seem minor when
bleeding stops after a paper cut or even
after an interventional procedure with
percutaneous venous access. However,
clot formation is a major biologic event.
The coagulation cascade involves the
merging of intrinsic and extrinsic pathways. The intrinsic pathway includes
enzymes and protein cofactors, more
specifically, factors V, VIII, IX, X, XI
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .CE
...
DIRECTED READING
and XII and prothrombin and fibrinogen. The same
types of glycoproteins make up the extrinsic pathway
but are more specifically factors V, VII and X, and prothrombin and fibrinogen.
When certain tissue factors come into contact with
blood plasma, the process begins. Eventually, through
binding, feedback and acceleration mechanisms, the
coagulation cascade ends with generation of fibrin and
clot formation. The cascade proceeds on membrane
surfaces; it is only on the membrane surfaces of certain
stimulated cells that the reactions involved in formation of blood clots can occur.3,5
The coagulation system leads to formation of thrombin, which is the enzyme that helps convert fibrinogen
to fibrin. The fibrinolytic system helps to break up the
clot formed by the fibrin after tissue repair is completed and the anticoagulation system should regulate
all of the enzymes in the coagulation and fibrinolytic
system to ensure that no excess bleeding or clotting
occurs. Clinicians refer to the sum of these systems and
elements as the hemostatic plug.7
Coagulation Factor Deficiency
There are hereditary and acquired causes of coagulation deficiency. Some of these have long been recognized; others were discovered only after the advent of
invasive surgeries. Liver disease, lupus, malnutrition,
von Willebrand disease and other conditions can cause
clotting disorders. Cancer also can affect coagulation
factors.8 Patients who have a malignancy are at a greater risk for venous thromboemboli. As a result, some
may require oral anticoagulation therapy.9
Hereditary Bleeding Disorders
Severe hemophilia A and B are examples of inherited disorders that can cause serious bleeding from
only minor trauma. Along with severe F11 deficiency,
these disorders prolong a patient’s activated partial
thromboplastin time. Researchers currently are testing
gene therapies to treat the disease. Other rare factor
deficiencies also can cause severe bleeding and some
patients have combined factor deficiencies that are
more difficult to identify in typical screening tests.10
Acquired Factor Deficiencies
Acquired coagulation factor deficiencies are common.
They may be secondary to other conditions that accelerate clearance of coagulation factors from the circulation;
liver diseases, such as some that decrease factor production; impaired synthesis of factors such as in vitamin K
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
deficiency; or conditions that increase destruction of
coagulation factors, such as thrombolytic therapy.
Some patients acquire hemophilia A although they
have no history of a bleeding disorder. Many of these
patients, who are older than the typical person with
hemophilia, have underlying automimmune disorders
or a history of other disorders and drug treatments
that have caused the development of alloantibody factor inhibitors.10
Other underlying factors that may affect a patient’s
coagulation status include cirrhosis, hepatitis and
hepatocellular carcinoma.11 In a study by Hylek et al,
patients who had diarrhea or decreased oral intake
(less nutrition overall), or who were taking more
warfarin than prescribed had increased risks of anticoagulation above therapeutic ranges.12 Patients who
are pregnant or who have a viral infection may experience altered coagulation status. Surgery can affect
coagulation, as can hepatic failure in patients who may
have inherited or acquired antithrombin deficiency.9
Hyperthyroidism and malnutrition or malabsorption
disease also affect coagulation.13
A simple change in diet can increase risk for thromboembolism.9 Vitamin K deficiency can cause clotting
problems and dietary or supplemental intake of vitamin K has a complex relationship with coagulation and
anticoagulation therapy.1 Dietary sources of vitamin
K include dark-green leafy vegetables, such as spinach
and broccoli, the viscera of animals (eg, beef liver),
green tea and soy.13,14
Supplements such as ginseng, garlic and St John’s
wort also are rich in vitamin K. High intake of these
supplements can increase bleeding risk for patients
on warfarin therapy.15 Some medications may increase
platelet levels; these include oral contraceptives and
estrogen.1 Treating physicians must work closely with
patients to understand, monitor and help control diet’s
effect on coagulation.15 This includes encouraging
patients to moderate intake of foods rich in vitamin K
and certain supplements.
Laboratory Studies
Many radiologic technologists are familiar with the
importance of laboratory values for blood-urea-nitrogen
(BUN) and creatinine. These results are important
because intravenous (IV) contrast media administration
potentially can affect kidney function. Interventional
radiology staff also should consider the results of certain
laboratory studies that may indicate postprocedure bleeding problems before beginning a procedure.
549
.CE
. . . . . . . . . . . . . . . . . . . . . . . . . . .......................................................................
BLEEDING RISKS
Radiographers who work in interventional radiology quickly learn the significance of certain laboratory
exam results and the role these exams have in ensuring the safety of interventional procedures. Although
interventional radiology procedures have increased
steadily in recent years, there is little in the way of
data or guidelines specifically on periprocedural
management of patients who have abnormal coagulation parameters as measured by laboratory studies.1
Interventional radiologists assess these parameters
when considering whether to perform or modify various interventional procedures.
For example, many patients are prescribed anticoagulant medications by their treating physicians,
usually to thin the blood and prevent clots that result
in thromboses or emboli. However, the use of anticoagulant medication delays a patient’s clotting times following an interventional procedure. When coagulation
parameter results are outside the normal range, the
risks of bleeding vs the benefits of the procedure must
be considered.16
It is important to note that the laboratory assays used
to measure the coagulation system do not represent actual coagulation function, but are based on measurement
of factors identified in the coagulation cascade. A physician must understand the distinction among the various
systems involved in hemostasis to effectively use coagulation parameters to assess a patient for bleeding risk.7
Common laboratory studies for coagulation are prothrombin time (PT) or international normalized ratio
(INR), activated partial thromboplastin times (aPTT)
and platelet count. If the platelet count is below normal
or any of the other lab values are elevated, the patient
may experience longer bleeding times following an
interventional procedure. These are the most common
laboratory tests requested by interventional radiologists
before they perform procedures.
Each physician has individual preferences regarding which lab tests to consider. For example, an interventional radiologist may use the PT and strictly limit
the time range to 1 second above the normal range.
Another radiologist may be comfortable performing any
procedure as long as the INR is less than 2.0. Yet another
physician may base the decision more heavily on the
patient’s medical history. Most of the studies concerning clotting problems and interventional procedures are
based on procedures that are conducted percutaneously.1 Regardless of the type of procedure to be completed,
coagulation lab values should be determined prior to
completing an interventional procedure.1
550
Prothrombin Time
PT is one of the coagulation parameters an interventional radiologist may assess before proceeding with a
procedure. Determining the mechanism for reporting
PT was developed through a trial and error process
that started toward the end of the 1800s. PT measures
thromboplastin components in the blood specimen.
Different thromboplastins can produce varying ranges
of PT values, and in 1983, the test was standardized
using the INR for reporting.1,5,17 Some physicians still
prefer PT; however, INR is the more acceptable measure. PT studies have helped maintain patient safety in
cardiovascular-interventional suites by assessing coagulation parameters and thus preventing patient complications such as hemorrhage and thrombosis.18
Prothrombin times vary based on a patient’s
comorbidities and underlying conditions. For example,
patients who have had chronic antibiotic treatment
are candidates for PT assessment because the treatment can cause decreased absorption of vitamin K,
which leads to clotting factor deficiency. Normal PT
values in a healthy adult range from 11 to 14 seconds.1
Anticoagulant medications affect PT results. A prolonged PT also may be caused by liver disease, lupus or
other conditions.11
PT usually is used to monitor the effectiveness of warfarin. Again, the patient’s medical history is important in
evaluating values because the interventional radiologist
must know the type of warfarin therapy the patient is
receiving. Prothrombin test results may not be reliable
for patients on low doses of warfarin or other anticoagulant medications. Despite normal test results, these
patients may be at increased risk for bleeding.
The INR is becoming the universal means of determining a patient’s clotting factors by monitoring the
use of oral anticoagulant therapy, as well as the standard measure for PTs.1 The INR value is calculated
based on an international standard that corrects for
variation among laboratories.19 Introduction of the
INR has helped to lower the frequency of bleeding incidents.20 The INR is calculated by dividing the patient’s
PT by a mean control PT.19
The normal INR range for adults is 0.9 to 1.1; however, some patients on medication are at a therapeutic value of 2.2 to 2.8.1 When a patient who is being
monitored has target ranges of 2.0 to 3.0, moderateintensity therapy usually is indicated.9 When a patient
is placed on medication, it is important that therapeutic INR levels be maintained. If a patient reaches an
INR > 4.0 and does not show any signs of bleeding, the
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .CE
...
DIRECTED READING
overanticoagulation may be corrected by withholding
some doses from the patient.15 Monitoring is particularly important when anticoagulant therapy begins, in
particular because some patients are more sensitive to
anticoagulant medications than others.18
Guidelines for INR assays suggest that INR levels
< 2.0 indicate an increased risk of thromboembolism,
whereas an INR value > 4.0 represents overanticoagulation and increased risk of bleeding.11,21 An INR > 4.0
could result in cranial hemorrhage.12 When monitoring
coagulation with INR levels, physicians also must monitor a patient’s diet. A diet high in vitamin K can cause
fluctuations in INR results.13
Patients may be placed on continuous anticoagulation for many weeks or months at a time. Even patients
whose assays repeatedly indicate therapeutic levels of
anticoagulation require INR monitoring every 4 weeks
to ensure that the values are within a therapeutic
range.2,15 Constant monitoring of these values is necessary, but can be expensive.15
Activated Partial Thromboplastin Time
Physicians treating patients with heparin use aPTT
values to monitor the heparin dosage to ensure the
patient remains within therapeutic ranges of anticoagulation.22 Unfractionated heparin inhibits clotting factors
that belong to the intrisic pathway.23 The aPTT laboratory assay is used to determine clotting times after activation of the intrinsic coagulation pathways. The normal
range of aPTT for an adult is 25 to 35 seconds.1
The aPTT is not useful for monitoring warfarin
therapy.1,5 If aPTT results in a time of > 60 seconds, the
measure may need to be repeated to ensure accuracy. If
the results are high on the repeat aPTT, the patient will
need fresh frozen plasma (FFP) to return coagulation
to normal levels.23 When assessing aPTT, knowledge of
the patient’s medical history helps the interventional
radiologist understand the reason for abnormal results.
For example, a patient may have been placed on IV heparin therapy; this anticoagulant medicine can be rapidly
discontinued and restarted to accommodate an interventional procedure. Or a patient may have a disease,
such as lupus, that prolongs the aPTT but does not cause
excessive bleeding.5
Platelet Count
An increase in the previously discussed coagulation
parameter values indicates risk of bleeding; on the other
hand, a decreased platelet count indicates increased risk
of bleeding from an interventional procedure. A platelet
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
count usually is performed as part of a complete blood
count.1 Platelets are cells in the blood that are required
for hemostasis and endothelial repair.23,24 Platelets appear
to play more of a role in arterial thrombosis than in
venous thrombosis.22 Platelets have a life span of about 10
days,24 after which they regenerate themselves.1 The relatively long life of platelets helps explain why physicians
may require a patient to halt aspirin therapy or use of
other antiplatelet medications for 7 to 10 days prior to an
interventional procedure.5
A normal platelet count is 150 000 to 450 000/µL.1
Platelet counts usually are used to diagnose or monitor bleeding disorders, thrombocytopenia, neoplastic
disorders or disseminated intravascular coagulation.
Platelet counts of < 20 000/µL can be life threatening.1
Coagulation-altering Medications
Several prescription medications are used to alter
coagulation, along with some over-the-counter and
alternative methods. Anticoagulant medications are
designed to affect the body in different ways; each
has a different chemical composition and binding
elements. The most commonly prescribed are warfarin and heparin. These medications disrupt normal
protein pathways of coagulation.22 Antiplatelet agents,
such as aspirin and clopidogrel, irreversibly inhibit
platelets.5,22 Aspirin is the most commonly used antiplatelet medication.1 Some other medications and
alternative medicines have antiplatelet or anticoagulant
effects and are discussed elsewhere.5
Anticoagulant Therapy
Use of oral anticoagulant medication to prevent
thromboembolism has been in practice for more than
50 years.14 Patients often are placed on anticoagulant
medications based on a current medical condition,
such as a recently diagnosed thrombus or atrial fibrillation. Many patients may be at an increased risk for
thromboembolism immediately following surgery and
may receive anticoagulant medication to prevent clots.
Each of these medications has different effects on the
body and alters lab results differently.25
Some anticoagulant medications are administered by IV infusion. Graded infusion is used when
it is necessary for the patient’s dosage to be tapered.
As a result, the patient receives the highest doses of
anticoagulant medication at the onset of therapy and
reduced doses later. Continuous infusion is used when
the patient is better served by a steady rate of anticoagulant medication.26
551
.CE
. . . . . . . . . . . . . . . . . . . . . . . . . . .......................................................................
BLEEDING RISKS
The treating physician should learn as much as
possible about a patient’s medical history before
administering oral anticoagulation. Some medical
conditions may cause oral anticoagulant medications
to affect a patient differently. For example, a patient
who has some forms of malignancy is at higher risk
for venous thromboembolic episodes.9 When patients
are monitored in a hospital setting, the treating physician will order a repeat set of coagulation lab assessments to keep a close watch on the patient who is
receiving anticoagulation medications for prevention
of thromboembolism.25
When a patient begins oral anticoagulation therapy
because of a thromboembolic event, the course of
therapy may run approximately 3 to 6 months.9 Elderly
patients often benefit the most from anticoagulant
therapy; frequent monitoring with INR values helps
prevent adverse events and improves outcomes in this
population.13 Many anticoagulant medications can be
prescribed for home use and monitored in a clinical
setting. For example, patients take oral anticoagulants
at home and return to their physician’s office or a
clinic for regular follow-up visits and monitoring with
laboratory studies. If the coagulation parameters are
outside the normal range, the physician works with
the patient to determine why and to adjust factors that
may alter its effectiveness. At times, the patient may be
told to halt oral anticoagulants for a limited time until
results show that anticoagulation has returned to the
normal range.21
The choice of medication is based on patient safety,
projected effectiveness and treatment and monitoring costs.25 Use of anticoagulant medication increases
the risk of hemorrhage, regardless of the medication
chosen. Risk of hemorrhage increases with duration of
treatment and intensity of anticoagulation.15 Treating
physicians carefully consider the risks vs benefits of
anticoagulant therapy for individual patients before
ordering the treatment.9
Monitoring and maintaining therapeutic values
in patients with cancer can be complicated. Cancer
patients on anticoagulation therapy have been shown
to require more frequent monitoring than cardiology
patients. In addition, cancer patients have higher rates
of underanticoagulation and overanticoagulation and
more frequent thromboembolic and major hemorrhagic complications.9
Oral anticoagulants such as warfarin antagonize
production of vitamin K-dependent clotting factors
in the liver. Some physicians have referred to oral
552
anticoagulants as vitamin K-antagonist medications.1,15
Not all patients react the same way to medication
prescribed for thromboembolism prevention. Some
patients may require a higher dosage to achieve
therapeutic reference levels. Other patients may be
more sensitive to medication and can reach appropriate coagulation sooner than expected. This is why
constant monitoring of response to anticoagulant
medications is extremely important. Without monitoring, a patient is at a risk of hemorrhage. Overdosage
increases the chance of hemorrhaging.
Heparin
The active agent in the anticoagulant medication
heparin is obtained from bovine lung or porcine intestinal mucosa.22 Heparin is used to prevent or treat venous
thromboemboli.1,27 Prompt initiation of heparin decreases chance of further clot formation.26 Fractionated
heparin has some clinical use, such as IV administration
for patients who need an invasive procedure in an emergency. However, unfractionated, or low-molecular-weight
heparin (LMWH) is used more often.27,28
Fractionated heparin is delivered with an IV bolus.
Delivery continues until the desired therapeutic range,
approximately 1.5 to 2.5 times normal aPTT value, is
achieved.1,27 LMWH is administered subcutaneously
and has a longer half-life than the unfractionated
form.1,5 Dosage for both forms of heparin is based on a
patient’s weight.1
LMWH usually is administered every 12 hours.
When heparin is used for prophylaxis, it may be given
every 24 hours. Prophylactic use may follow a surgical procedure.1 Recurrent thromboemboli usually
require 4 to 5 days of treatment.15 Careful monitoring
of heparin with aPTT values is essential.1 Presence of
heparin in a patient’s blood can affect coagulation
assay results, and any PT time > 18 seconds should be
repeated to determine whether the patient’s blood
was completely cleared of heparin. If the results still
are higher than normal, the patient may need to be
treated for altered coagulation.23
Warfarin
Warfarin also is a form of anticoagulant medication used to treat and prevent thromboemboli.22 It is
one of the most frequently prescribed anticoagulation medications in the United States, although its
use in the elderly population is less frequent than in
the general population because of the comorbidities
many elderly patients have that can affect warfarin’s
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .CE
...
DIRECTED READING
effectiveness.1,13 Warfarin most frequently is used to
help prevent thromboses in patients with systemic
thromboembolic disorders or history of venous or arterial thrombosis, including patients with chronic, recurrent thromboemboli.11,20 Patients who have congestive
heart failure or who are at risk for stroke may receive
warfarin therapy.1
Warfarin may not take full effect until a patient has
received the medication for 3 to 4 days. This is because
warfarin has a longer half-life than heparin, about 37
hours, and its anticoagulant effect depends on clotting
factors that have a half-life of 96 hours.5,13 Treating
physicians may overlap heparin with the first few days
of warfarin therapy until the warfarin takes effect.13
Although effective at thrombosis prevention, warfarin can cause hemorrhaging.12 The medication must
be given in small doses and carefully monitored to
decrease risk of bleeding upon initiation of therapy.9
Warfarin is a competitive vitamin K antagonist. It
inhibits the ability of vitamin K-dependent coagulation
proteins to form.18 These proteins include factors II, VII,
IX and X and proteins C and S.5,11 Diets rich in vitamin
K can interfere with the anticoagulation response of
warfarin.13 Patients on warfarin therapy who drink excessive alcohol may have altered hemostasis.29 Their INR
value may increase to 6.0 or higher while on the medication. It is recommended that patients on anticoagulation
therapy moderate alcohol use.12
Patients receiving warfarin treatment require
close monitoring of INR values because of individual
patient response and the fact that many medications,
comorbidities and dietary factors can affect anticoagulation response during warfarin therapy.21,27 Patients
may have to report to their physicians use of certain
over-the-counter or prescription medications, dietary
supplements that contain vitamin K and other alternative medications. Poor compliance with instructions
regarding warfarin dosage also can affect coagulation
response.27 Even at low doses, a patient on warfarin
needs to be monitored closely for increased risk of
bleeding.18 The treating physician must balance dosage
to keep a patient’s hemostatic system balanced between
overanticoagulation and underanticoagulation.18
Antiplatelet Medications
Aspirin is an antiplatelet medication and aspirin
therapy is commonly used to prevent cardiovascular
events.5,29 However, the use of aspirin may make the
difference between major and minor bleeding events
following a procedure.29 Aspirin has been shown in
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
the past to prolong bleeding in patients because of
its inhibition of the prostaglandin endoperoxides in
platelets.30 However, other studies have shown that use
of aspirin therapy increases intraoperative bleeding
only in neurologic surgery.1 Aspirin doses vary widely
in practice, from 75 mg/day to 325 mg/day. As little as
30 mg/day can inhibit platelet production. A report by
Steinhubl et al suggested that doses of 100 mg/day or
higher offered no significant benefit compared with
lower doses and could harm patients by causing gastrointestinal toxicity or severe bleeding.31
Clopidogrel bisulfate and similar prescription antiplatelet medications have been prescribed to help thin
the blood and prevent clots and strokes. Standard dosing for clopidogrel is 75 mg/day in oral tablet form.
Like aspirin, clopidogrel irreversibly inhibits platelets,
but only 50% to 60% of a patient’s platelets at the standard dose. Patients should reach a steady state in about
7 days and normal platelet function should return 7
days after the last clopidogrel dose.4,5
Clopidogrel has a mixed safety record. In 2010, the
U.S. Food and Drug Administration issued a boxed
warning because clopidogrel metabolizes poorly in
some patients and is therefore less effective. The warning advised health care professionals to consider using
other antiplatelet medications or adjust dosing strategies for patients who do not metabolize the drug well.32
The Table summarizes anticoagulant and antiplatelet medication laboratory parameters.
Coagulation in Interventional Radiology
For patients at higher risk for bleeding complications following surgery or interventional procedures,
planning the use of anticoagulant medications before
the procedure is critical.25 There are risks involved
when starting a patient on anticoagulant medication
and the risk of excessive bleeding may be higher during the first month of use.15 These patients must be
carefully monitored when undergoing interventional
procedures.1 The risk of bleeding is higher at the site of
pre-existing lesions.15
Some interventional procedures have a higher risk
of bleeding than others. Consensus guidelines from
the Society of Interventional Radiology have placed
many procedures into 3 categories1:
■ Category 1: procedures with low risk of bleeding,
easily detected and controllable. This category
includes vascular procedures such as peripherally
inserted central catheter (PICC) line placement
and nonvascular procedures, such as thoracentesis.
553
.CE
. . . . . . . . . . . . . . . . . . . . . . . . . . .......................................................................
BLEEDING RISKS
forming but the
interventional radiologist is reluctant
Anticoagulant Medication
Bleeding Risk
Precautions
to complete a proParameters
cedure on a patient
who is taking these
Heparin
aPTT 1.5-2.5 times mean
If aPTT times are very long
medications because
normal range
postoperatively, this sugof increased risk
gests heparin as the cause.
of bleeding. These
Protamine can help rapidly
physicians must
reverse heparin effects.
evaluate the patient’s
Warfarin
INR > 4.0
Absolute risk is greatest early
history and laborain therapy; cumulative risk
tory results to reach
increases with therapy duration.
a compromise that is
Antiplatelet Medication
best for the patient.
Communication,
Platelet count and withholding
Aspirin
Platelet counta approx.
institutional proto50 000/µL
of aspirin therapy for 5 days
cols and following
only recommended for highconsensus guidelines
risk procedures.
can help avoid disa
Clopidogrel
Platelet count approx.
Research is limited on clopiagreements among
50 000/µL
dogrel. Platelet count and
physicians and guide
withholding of therapy for 5
decisions concerning
days recommended for highperiprocedural antirisk procedures.
coagulation managea
Platelet count generally is not a good predictor of bleeding complications.
ment. The physician
aPTT = activated partial thromboplastin time; INR = international normalized ratio.
responsible for regular maintenance of
the patient’s therapy and the interventional radiologist
■ Category 2: procedures with moderate risk of
should come to agreement regarding the anticoagulableeding. Vascular procedures in category 2
tion therapy plan before the procedure begins.2
include transjugular liver biopsy and uterine
An increased PT usually indicates increased potenfibroid embolization. Nonvascular interventions
tial for bleeding complications.18 It is not uncommon
include lung biopsy and initial placement of a
for an interventional radiologist to consider a PT of up
gastrostomy tube.
to 3 seconds greater than the normal range a safe zone
■ Category 3: procedures with significant bleeding
for going ahead with a procedure.19
risk, difficult to detect or control. Transjugular
intrahepatic portosystemic shunt placement is
Medication Considerations
the vascular procedure in this high-risk category.
Surgery usually must be delayed until at least 12
Nonvascular procedures include renal biopsy, bilhours after a patient’s last dose of LMWH. Some practiiary interventions (new tract), nephrostomy tube
tioners believe it is safe to begin an interventional proplacement and complex radiofrequency ablation.
cedure within 5 hours of the last dose of heparin.22
The guidelines also list the preprocedure laboratory
Heparin sometimes is administered by nurses durtesting generally recommended for the particular intering interventional procedures involving the vascular
ventional procedure and recommended management.1
system, such as angioplasty. Heparin has a half-life
of 30 to 90 minutes.22 This short half-life is an advanPeriprocedural Planning
tage for use in interventional radiology procedures.27
Sometimes removing a patient from anticoagulant
Anticoagulation effects of fractionated heparin cease
medication causes a conflict between physicians. The
within about 3 hours following the discontinuation of
referring physician is reluctant to remove a patient
IV infusion.27
from the medications because of risk of blood clots
Table
Summary of Bleeding Risk Indicators for Medications1,5,27
554
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .CE
...
DIRECTED READING
Physicians may request the administration of
protamine sulfate to neutralize the effects of heparin
if necessary. Protamine can lead to an allergic reaction if infused too quickly; therefore, patients usually
receive protamine through a slow IV infusion1 over 1
to 3 minutes.22 In addition to allergic and anaphylactic reaction, patients may experience hypotension or
bradycardia when protamine is infused too quickly.
Protamine dosage is based on length of heparin infusion time. For an infusion time of < 30 minutes, 1 mg
of protamine per 100 units of heparin is recommended. The dosage amount decreases as the length of
infusion time increases.22 An example of protamine
use is when vascular surgeons treat patients for
peripheral arterial disease.
Patients on warfarin may need to have warfarin
anticoagulation reversed before a procedure can be
performed. Exceptions may be emergency procedures.23 In these cases, the physician must consider
risks and benefits of reversal.
Vitamin K sensitivity can cause varying results and
makes it difficult for interventional radiologists to
set a static threshold for a procedure based on PT
values alone; medical history also is important. 5,18
Foods such as broccoli and spinach that are rich
in vitamin K can affect the anticoagulation factors
reflected by PT and INR values, but only if eaten in
high amounts.15
Consensus guidelines generally recommend that
patients on aspirin therapy continue its use for all
interventional procedures except those with the most
significant bleeding risk. When this decision is made,
patients usually stop their aspirin therapy 5 days
before the procedure.1 Many interventional radiologists suggest that aspirin therapy be stopped before a
scheduled procedure, but O’Connor et al reported in
2009 that many studies have shown that continuation
of aspirin therapy is safe for a number of interventional procedures. 5 Consensus guidelines generally
recommend withholding aspirin for 5 days only for
procedures with significant bleeding risk, such as
renal biopsies and biliary interventions.1 The effects
of clopidogrel on bleeding during interventional
procedures have not been studied extensively. If a
patient can safely stop the drug, this should be done
3 to 5 days before an interventional procedure. Not
all of the inhibited platelets return, but about 50% of
platelets will have normal function by the time of the
procedure and the timing keeps the patient within a
safety window for therapy disruption.1,5
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
Correcting Coagulation Problems During
Interventional Procedures
Professionals who perform interventional radiology
procedures must recognize that patients’ coagulation
systems can be affected by several factors in addition to
anticoagulation therapies.
The patient’s medical history can help to differentiate the underlying reasons for his or her altered coagulation. If a patient has a normal aPTT but a prolonged
PT, the patient may be on warfarin therapy, have liver
disease, a deficiency in vitamin K or factor VII, or an
inhibitor of factor VII.8 A prolonged PT and elevated
INR also may indicate lupus, bile duct obstruction or
malabsorption.1 Liver disease also may be indicated by
a prolonged aPTT and a prolonged PT.8
Interventional radiologists may have to order platelet
transfusions for patients with severe thrombocytopenia,
a persistent and severe decrease in the number of platelets. Physicians probably would do so only after consideration of many variables, including platelet count and
function, type of procedure, the operator’s expertise
and the patient’s comorbidities. Studies have shown that
patients who have a platelet count < 100 000 µL have a
higher incidence of hematoma following angiography
procedures with groin entry.1
Anticoagulation Reversal
Monitoring laboratory values and withholding
anticoagulant medications as needed are among the
strategies used to reverse anticoagulation for invasive
procedures.5,27 At times, patients receive too much anticoagulant medication and additional intervention is
required before an interventional radiologist can safely
proceed with a procedure. Bleeding, surgery, trauma
and other conditions that can alter coagulation also
might lead to overcoagulation.
Several interventions can be used to treat altered
coagulation. They may be used alone or together and
may not always be effective. These interventions also
are accompanied by risks.5
Fresh Frozen Plasma
FFP is a blood product that has been separated
from the red blood cells and platelets and contains
plasma proteins.5,23 FFP has an expiration date of 1 year
from donation and must be stored at a temperature of
–18°C.23
Each year more than 3 million units of FFP are
transfused in the United States alone and many of these
transfusions are unnecessary.1,33 The guidelines for use
555
.CE
. . . . . . . . . . . . . . . . . . . . . . . . . . .......................................................................
BLEEDING RISKS
of FFP are vague and physicians may administer the
product to patients with varying INR values, depending
on the physician’s individual policies, comfort level with
a procedure and medical-legal concerns 1,5 Guidelines
and procedures for administration of FFP also may vary
among and within institutions. Prophylactic use of FFP
for patients who are not bleeding before an invasive
procedure has not been proven to lower bleeding risk.5
FFP may be administered before an invasive procedure for critically ill patients with elevated INR values
and high bleeding risk.33 On some occasions FFP may
be administered following a procedure, regardless of
whether the patient’s coagulation is impaired.33 There is
no guarantee that transfusing FFP will prevent bleeding
in a patient after a procedure is completed.33
Physicians also determine the amount of FFP needed
to help return a patient’s coagulation status to an acceptable level.23 Patients often receive 1 to 2 units of FFP to
increase clotting factors, but this is arbitrary and insufficient in some patients. Dose commonly ranges from 15
to 30 mL/kg.1,5 More FFP may be may be required if INR
values do not return to a normal level. Vitamin K may be
added to FFP administration.1
FFP introduces infection risk and can cause allergic or
anaphylactic reactions.5 A patient must have a blood type
and screen completed to match the type before receiving FFP. Use of FFP transfusion includes risk of human
immunodeficiency virus (HIV) infection.16
Too much FFP can lead to risks such as volume
overload. 5 An emerging concern with use of FFP
is the risk of transfusion-related acute lung injury
(TRALI). Of all blood components, FFP is responsible for more deaths from TRALI than any other. A
retrospective review of deaths from TRALI during
the 5-year period from 1997-2002 found that FFP
administration was implicated in 50% of 58 deaths
reported to the FDA. 34
Aside from concerns regarding effectiveness and
risks, use of FFP can complicate scheduling of procedures. The FFP unit can be frozen for up to 1 year but
must be thawed before infusion. This can take up to
20 minutes and requires careful attention to infection
control, which takes time and money.34,35 Radiology
departments may experience waiting times for the
product that affect timeliness of the procedure and
can make it difficult for those performing procedures
to schedule precisely. After thawing, FFP must be
refrigerated and transfused within no more than 24
hours. FFP is thought to progressively lose hemostatic
effect the longer it has been in a thawed state.35
556
Cryoprecipitate
Blood banks can manufacture cryoprecipitate by
thawing FFP at 4°C and removing the layer that separates out, or precipitates, in this state. The resulting
product is rich in factors VIII, XIII, fibronectin, fibrinogen and von Willebrand factor. The factors are suspended in a smaller amount of plasma (20 to 40 mL)
than FFP, which makes them more concentrated than
in a typical whole-blood unit. Cryoprecipitate may be
used to help correct overanticoagulation by increasing
the blood’s fibrinogen level. Blood type compatibility is
not required for cryoprecipitate use, but is preferred.1,35
In the review of TRALI reported to the FDA, only 2%
of cases were caused by cryoprecipitate.34
Desmopressin
The synthetic agent desmopressin promotes release
of von Willebrand factor from the endothelium,
increases density of glycoprotein receptors that help
improve platelet adhesiveness and increases plasma
activity of factor VIII. Desmopressin may be indicated
in patients with hemophilia, von Willebrand disease,
acquired platelet disorders or those with bleeding
caused by nonsteroidal anti-inflammatory drugs or
aspirin. It is administered in 0.3 µg/kg IV infusion over
20 to 30 minutes and is diluted in 100 mL of saline.
Desmopressin can cause water retention, facial flushing, headache and small decreases in blood pressure. It
can increase risk of seizure, particularly in infants and
children, and can cause acute coronary syndrome in
patients with pre-existing coronary artery disease.1,35
Vitamin K
Vitamin K, or phytonadione, can help normalize
a patient’s coagulation. The choice to use vitamin K
vs FFP transfusion is made by the treating physician
based on the patient’s medical history. Vitamin K can
be administered orally, subcutaneously or intravenously. The means of administration depends on the
desired time frame for reversal of overanticoagulation.
For example, vitamin K takes effect more quickly when
administered subcutaneously, although rates of absorption vary among patients.1,15 Intravenous dosage usually
is 0.5 mg to prevent overcorrection of anticoagulation.15
Vitamin K may be given to patients before a procedure as a prophylactic, but this probably is not effective because vitamin K does not reach full effect for
12 to 24 hours following administration.15 Vitamin K is
administered alone or in conjunction with FFP. As with
other means of reversal, a patient still may bleed after
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .CE
...
DIRECTED READING
the administration of vitamin K. A more rapid correction of overanticoagulation is achieved if vitamin K is
administered in small oral dosage (1 mg) increments.15
Other Hemostatic Agents
Sometimes pharmacological agents are used to prevent or control severe bleeding, particularly if there is
no surgical cause of coagulation abnormality identified
as the cause of severe bleeding. These include antifibrinolytic agents and recombinant activated factor VIIa.
When the cause is hemostatic function, the physician
usually can treat the problem by replacing the defective
component. Physicians also should plan how they will
monitor medication dosage before beginning a procedure with high bleeding risk.25 A physician may need to
correct altered coagulation during a procedure. This
may involve changing medications. The use of these
agents increases the risk for thrombosis, particularly for
patients who have atherosclerosis or already are at risk
for thrombosis.25 There are some medical conditions
patients have in which pharmacologic treatment may
actually increase the risk of hemorrhage following a
procedure.26 Some patients may experience major hemorrhaging, which can lead to death. Other patients may
have only minor hemorrhaging, which is corrected with
minor intervention.15
Risk vs Benefit
Every time a referring physician orders a procedure,
the risks vs benefits must be deliberated for the individual patient. Whatever choice is made, the patient must be
made aware of the benefits and risks involved. Informed
consent should be obtained for all invasive procedures
that involve incisions or insertion of needles or catheters.
This includes explaining significant risks and benefits of
the procedure and alternatives available to the patient.
According to the American College of Radiology (ACR),
informed consent “is a process and not the simple act of
signing a formal document.” However, the form signed
by the patient documents the discussions held.36
There is an increased risk of bleeding for patients
during the first 28 days after the initiation of warfarin
treatment. Older patients (median 71 years old) are particularly at increased risk of bleeding postprocedure,21
largely because of medication interactions. Patients who
have cerebrovascular disease or peripheral vascular
disease also are at increased risk of bleeding.15 Careful
attention to coagulation parameters aids the physician in
minimizing the possibility of postprocedural bleeding or
hematoma. Unfortunately, there are still times when the
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
bleeding cannot be stopped. Up to 20% of patients may
still have prolonged bleeding following an invasive procedure regardless of careful monitoring.18
Many factors must be considered regarding a patient’s
coagulation status before performing an interventional
procedure. Patient safety is of utmost concern.1 However,
emergency cases do not always allow time for full weighing of risks vs benefits. Emergency procedures sometimes must be completed with the hope that the procedure will help to save the patient’s life. For example, a
patient with acute limb ischemia may need to be treated
immediately with no time to attempt to correct coagulation function.26 Interventional radiology departments
should follow guidelines such as those from the ACR, as
well as institutional policies, regarding informed consent
in emergency situations.36
Nonemergency procedures allow more time to consider the risks involved.1 Considerations may include
any reason the patient is at increased risk for failure to
clot following a procedure. In addition, physicians must
consider whether the patient can withstand a procedure regardless of bleeding risk.26
Use of image guidance can help reduce bleeding
during the procedure as the interventional radiologist
can see the area of interest and thus be more accurate
in targeting the area (eg, in needle biopsy). However,
use of image guidance during procedures can limit the
operator’s ability to directly visualize postprocedural
bleeding, as is possible in open surgical procedures.1,14
Observing bleeding following a procedure can be
difficult in some situations. When the entry site is in a
partially hidden area of the body, there may be a delay
in the detection of bleeding.1 Once it is determined that
there is excessive or prolonged bleeding, the decision
must be made whether to continue a patient on anticoagulation therapy. The location of the bleeding may hinder the continuation of anticoagulation medication.26
Role of the Radiologic Technologist and
Radiologist Assistant
The wide variation among interventional radiologist preferences and practice regarding interpretation
of coagulation parameters and when to proceed with
a planned interventional procedure presents special
challenges for radiologic technologists, radiologist
assistants and other supporting staff. Staff must remain
aware of the concerns and treatments that can be used
to normalize anticoagulation. Radiologist assistants
may assess and manage patients before and following
procedures, according to ACR guidelines. This can
557
.CE
. . . . . . . . . . . . . . . . . . . . . . . . . . .......................................................................
BLEEDING RISKS
include monitoring anticoagulation conditions before
and after a procedure. The radiologist assistant transmits observations to the interventional radiologists that
will have a bearing on diagnosis and follows the directions of the supervising interventional radiologist.37
Conclusion
Use of laboratory assays that measure coagulation
parameters can help physicians determine whether a
patient is at risk for severe bleeding following an interventional procedure. Lab results such as prolonged
prothrombin time, measured as INR, or elevated aPTT
can indicate increased risk of bleeding. A platelet count
below normal range also is an important indicator of
increased risk of bleeding.
Coagulation can be measured according to laboratory parameters and adjusted by transfusing platelets,
FFP or administering vitamin K or pharmacologic
agents. Some medications alter a patient’s coagulation
status. Usually a person is given anticoagulant medication to help prevent thrombosis or another medical
condition. When patients are using these medications,
their coagulation parameters must be monitored routinely to maintain the patient’s coagulation within
therapeutic ranges. However, use of these medications
can limit the ability to perform certain interventional
procedures because of increased risk of bleeding.
When treating patients with altered coagulation, the
physician must be aware of the underlying reason. It is
important for interventional radiologists and their staffs
to be aware of their patients’ medical histories and work
closely with referring physicians in monitoring patients
before, during and after interventional procedures.
References
1. Malloy PC, Grassi CJ, Kundu S, et al. Standards of practice committee with cardiovascular and interventional
radiological society of Europe (CIRSE) endorsement.
Consensus guidelines for periprocedural management of
coagulation status and hemostasis risk in percutaneous
image-guided interventions. J Vasc Interv Radiol. 2009;
20(suppl 7):S240-S249.
2. Garcia DA, Witt DM, Hylek E, et al. Delivery of optimized
anticoagulant therapy: a consensus statement from the
anticoagulant forum. Ann Pharmacother. 2008;42(7):979988. www.medscape.com/viewarticle/578389. Accessed
April 22, 2010.
3. Furie B, Furie BC. Molecular basis of blood coagulation.
In: Hoffman R, Benz EJ Jr, Shattil SJ, et al, eds. Hematology:
Basic Principles and Practice. 5th ed. Philadelphia, PA:
Churchill Livingstone Elsevier; 2009:1818-1836.
558
4. Gaines KK. Management of anticoagulation therapy for
invasive procedures. Medscape Today Web site. www
.medscape.com/viewarticle/514535. Published November
28, 2005. Accessed April 22, 2010.
5. O’Connor SD, Taylor AJ, Williams EC, Winter TC.
Coagulation concepts update. AJR Am J Roentgenol.
2009;193(6):1656-1664.
6. Dahlback B, Stenflo J. Regulatory mechanisms in hemostasis: natural anticoagulants. In: Hoffman R, Benz EJ
Jr, Shattil SJ, et al, eds. Hematology: Basic Principles and
Practice. 5th ed. Philadelphia, PA: Churchill Livingstone
Elsevier; 2009:1843-1850.
7. Schmaier AH. Laboratory evaluation of hemostatic and
thrombotic disorders. In: Hoffman R, Benz EJ Jr, Shattil
SJ, et al, eds. Hematology: Basic Principles and Practice. 5th
ed. Philadelphia, PA: Churchill Livingstone Elsevier;
2009:1877-1884.
8. Cuker A, Connors JM, Katz JT, et al. Clinical
problem-solving: a bloody mystery. N Engl J Med.
2009;361(19):1887-1894.
9. Wittkowsky AK. Anticoagulation in hypercoagulable
conditions: special considerations in the treatment and
prevention of venous thromboembolism. J Pharm Pract.
2004;17(5):308-316.
10. Wagenman BL, Townsend KT, Mathew P, Crookston KP.
The laboratory approach to inherited and acquired coagulation factor deficiencies. Clin Lab Med. 2009;29(2):229-252.
11. Furie B, Liebman HA, Blanchard RA, Coleman MS,
Kruger SF, Furie BC. Comparison of the native prothrombin antigen and the prothrombin time for monitoring oral
anticoagulant therapy. Blood. 1984;64(2):445-451.
12. Hyleck EM, Heiman H, Skates S, Sheehan MA, Singer DE.
Acetaminophen and other risk factors for excessive warfarin anticoagulation. JAMA. 1998;279(9):657-662.
13. Dowd MB. Anticoagulation in the elderly. J Pharm Pract.
2004;17(2):94-102.
14. de Assis MC, Rabelo ER, Avila CW, Polanczyk CA, Rohde
LE. Improved oral anticoagulation after a dietary vitamin K-guided strategy: a randomized controlled trial.
Circulation. 2009;120(12):1115-1122.
15. Schulman S. Care of patients receiving long-term anticoagulant therapy. N Engl J Med. 2003;349(7):675-683.
16. Stecker MS, Johnson MS, Ying J, et al. Time to hemostasis
after traction removal of tunneled cuffed central venous
catheters. J Vasc Interv Radiol. 2007;18(10):1232-1239.
17. Quick AJ. The development and use of the prothrombin
tests. Circulation. 1959;19(1):92-96.
18. Kornberg A, Francis CW, Pellegrini VD Jr, Gabriel KR,
Marder VJ. Comparison of native prothrombin antigen
with the prothrombin time for monitoring oral anticoagulant prophylaxis. Circulation. 1993;88(2):454-460.
19. Smith DC, Westengard JC, Bull BS. The international
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .CE
...
DIRECTED READING
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
normalized ratio (INR): hope for an uncertain result. J
Vasc Interv Radiol. 1996;7(1):3-4.
Brummel KE, Paradis SG, Branda RF, Mann KG. Oral anticoagulation thresholds. Circulation. 2001;104(19):2311-2317.
Schwarz UI, Ritchie MD, Bradford Y, et al. Genetic determinants of response to warfarin during initial anticoagulation. N Engl J Med. 2008;358(10):999-1008.
Mehta RP, Johnson MS. Update on anticoagulant medications for the interventional radiologist. J Vasc Interv Radiol.
2006;17(4):597-612.
Lundberg GD. Practice parameter for the use of freshfrozen plasma, cryoprecipitate, and platelets. JAMA.
1994;271(10):777-781.
Davi G, Patrono C. Platelet activation and atherothombosis. N Engl J Med. 2007;357(24):2482-2494.
Mannuci PM, Levi M. Prevention and treatment of major
blood loss. N Engl J Med. 2007;356(22):2301-2311.
Rajan DK, Patel NH, Valji K, et al. Quality improvement
guidelines for percutaneous management of acute limb
ischemia. J Vasc Interv Radiol. 2005;16(5):585-595.
Francis CW. Antithrombotic agents. In: Kitchens CS, Alving
BM, Kessler CM. Consultative Hemostasis and Thrombosis. 2nd
ed. Philadelphia, PA: Saunders; 2007:452-454.
Baglin T, Barrowcliffe TW, Cohen A, Greaves M. British
Committee for Standards in Haematology. Guidelines
on the use and monitoring of heparin. Br J Haemotol.
2006;133(1):19-34.
Walker AM, Jick H. Predictors of bleeding during heparin
therapy. JAMA. 1980; 244(11):1209-1212.
Amrein PC, Ellman L, Harris WH. Asprin-induced prolongation of bleeding time and perioperative blood loss.
JAMA. 1981;245(18):1825-1828.
Steinhubl SR, Bhatt DL, Brennan DM, et al. Aspirin to
prevent cardiovascular disease: the association of aspirin
dose and clopidogrel with thrombosis and bleeding. Ann
Intern Med. 2009;150(6):379-386.
Clopidogrel. Medline Plus. National Library of Medicine
and National Institutes of Health website. www.nlm.nih
.gov/medlineplus/druginfo/meds/a601040.html. Revised
January 1, 2010. Accessed April 19, 2010.
Lauzier F, Cook D, Griffith L, Upton J, Crowther M. Fresh
frozen plasma transfusion in critically ill patients. Crit Care
Med. 2007;35(7):1655-1659.
Spiess BD. Treating heparin resistance with antithrombin or
fresh frozen plasma. Ann Thorac Surg. 2008;85(6):2153-2160.
Ridley S. Medical management of bleeding in critically ill
patients. Medscape Today website. www.medscape.com
/viewarticle/563820. Published October 8, 2007. Accessed
April 23, 2010.
American College of Radiology. ACR Practice Guideline
on Informed Consent for Image-guided Procedures. www
.acr.org/SecondaryMainMenuCategories/quality_safety
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
/guidelines/iv/informed_consent_image_guided.aspx.
Revised 2006. Accessed April 23, 2010.
37. American College of Radiology. ACR Practice Guideline
for Interventional Clinical Practice. www.acr.org
/SecondaryMainMenuCategories/quality_safety/guide
lines/iv/interventional_clinical_practice.aspx. Revised
2009. Accessed May 4, 2010.
Amy Morris, AA, R.T.(R), is an interventional radiology
technologist at the Veterans Administration Medical Center in
Jacksonville, Mississippi. She has worked at the VA Medical
Center for 9 years and in interventional radiology for 3 years.
She also is a busy mother of 2 children.
Teresa G Odle, ELS, contributed to this Directed Reading.
Reprint requests may be sent to the American Society of
Radiologic Technologists, Communications Department,
15000 Central Ave SE, Albuquerque, NM 87123-3909, or
e-mail [email protected].
©2010 by the American Society of Radiologic Technologists.
559
Directed Reading Continuing Education Quiz
#10804-02
Expiration Date:
August 31, 2012*
Approved for 1.0
Cat. A+ CE credit
Bleeding Risks in
Interventional Radiology
To receive Category A+ continuing education credit for this Directed Reading, read the preceding article and circle
the correct response to each statement. Choose the answer that is most correct based on the text. Transfer your
responses to the answer sheet on Page 564 and then follow the directions for submitting the answer sheet to the
American Society of Radiologic Technologists. You also may take Directed Reading quizzes online at www.asrt.org.
Effective October 1, 2002, new and reinstated members are ineligible to take DRs from journals published prior to
their most recent join date unless they have purchased a back issue from ASRT. Your access to Directed Reading
quizzes for Continuing Education credit is detemined by your area of interest. For 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.
1.
2.
3.
According to the Directed Reading, the key to
preventing severe bleeding from interventional
procedures is _______ .
a. use of fresh frozen plasma (FFP)
b. control of the patient’s diet
c. postprocedural management
d. periprocedural management
The coagulation cascade can occur:
a. anywhere in the blood system.
b. anywhere on a cell surface.
c. only on malignant cells.
d. only on the membrane surfaces of certain
stimulated cells.
Clinicians refer to the sum of the systems and
elements that make up the fibrinolytic and
coagulation systems to control bleeding and
clotting as the hemostatic _______ .
a. regulator
b. plug
c. ring
d. value
4.
Dietary sources of vitamin K include which of the
following?
1. spinach
2. green tea
3. soy
a.
b.
c.
d.
1 and 2
1 and 3
2 and 3
1, 2 and 3
5.
The use of anticoagulant medication _______ a
patient’s clotting times following an interventional
procedure.
a. delays
b. speeds up
c. makes sporadic
d. does not affect
6.
Normal prothrombin time (PT) values in a
healthy adult range from _______ to _______
seconds.
a. 5; 8
b. 11; 14
c. 15; 18
d. 21; 24
Continued on next page
560
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
Directed Reading Continuing Education Quiz
7.
8.
9.
The _______ is becoming the universal means
of determining a patient’s clotting factors by
monitoring the use of oral anticoagulant therapy,
as well as the standard measure for prothrombin
times.
a. activated partial thromboplastin time (aPTT)
b. platelet count
c. international normalized ratio (INR)
d. red blood cell count
Guidelines for INR assays suggest that INR
levels < _______ indicate an increased risk of
thromboembolism.
a. 1.0
b. 2.0
c. 3.0
d. 4.0
Physicians treating patients with heparin use
_______ values to monitor the heparin dosage.
a. INR
b. platelet count
c. aPTT
d. creatinine
10. The aPTT is useful for monitoring warfarin
therapy.
a. true
b. false
11. A normal platelet count is _______ to _______ /µL.
a. 20 000; 40 000
b. 50 000; 75 000
c. 100 000; 125 000
d. 150 000; 450 000
12. When patients are prescribed anticoagulant
medication, the risk of hemorrhage increases
with:
1. duration of treatment.
2. intensity of anticoagulation.
3. cost of the medication chosen.
a.
b.
c.
d.
1 and 2
1 and 3
2 and 3
1, 2 and 3
13. When using low-molecular-weight heparin to treat
recurrent thromboemboli, treatment usually lasts:
a. 24 hours.
b. 4 to 5 days.
c. 1 to 2 weeks.
d. indefinitely.
14. Which of the following statements are true
regarding warfarin?
1. Warfarin takes effect in 24 hours.
2. Warfarin has a longer half-life than heparin.
3. Treating physicians may have to overlap warfarin and heparin therapy.
a.
b.
c.
d.
1 and 2
1 and 3
2 and 3
1, 2 and 3
15. As little as _______ mg/day of aspirin can inhibit
platelet production.
a. 10
b. 30
c. 50
d. 100
Continued on next page
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
561
Directed Reading Continuing Education Quiz
16. In 2010, the U.S. Food and Drug Administration
issued a boxed warning for the medication
_______, which metabolizes poorly in some
patients.
a. clopidogrel
b. warfarin
c. heparin
d. protamine
17. The risk of excessive bleeding for patients on
anticoagulant medication may be higher:
a. only after the first dose.
b. only when coagulation parameters indicate
risk.
c. during the first week of use.
d. during the first month of use.
18. If infused too quickly protamine can
cause _______ .
1. allergic reaction
2. hypotension
3. bradycardia
a.
b.
c.
d.
1 and 2
1 and 3
2 and 3
1, 2 and 3
21. A more rapid correction of overanticoagulation is
achieved if vitamin K is administered in:
a. intravenous bolus injection.
b. slow infusion with sterile saline.
c. large oral doses (10 mg).
d. small oral doses (1 mg increments).
22. The following statements are true concerning
informed consent for interventional radiology
procedures except that informed consent:
a. should be obtained for all invasive procedures
that involve incisions or insertion of needles
or catheters.
b. should include explanations of significant
risks and benefits.
c. is the simple act of signing a formal document.
d. documents discussions held with the patient.
23. _______ may assess and manage patients before
and following procedures, according to American
College of Radiology guidelines.
a. Patient transportation aides
b. Limited x-ray machine operators
c. Radiologic technologists
d. Radiologist assistants
19. Interventional radiologists may have to order
platelet transfusions for patients with severe
thrombocytopenia.
a. true
b. false
20. Of all blood components, _______ is responsible
for the most deaths from transfusion-related acute
lung injury.
a. red blood cells
b. platelets
c. FFP
d. cryoprecipitate
562
For your convenience, the evaluation and answer
sheet for this Directed Reading now immediately
follow the quiz. Just turn to Pages 563 and 564.
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
✁
Carefully cut or tear here.
CE
....................................................................... . . . . . . . . . . . . . . . . . . . . . . . . . . .
DIRECTED READING
Diagnosis and Treatment
Of Ocular Disorders
JANET YAGODA SHAGAM, PhD
Although by no means
comprehensive, this article
reviews some of the common
diseases, disorders and injuries to the eye that may occur
in patients seen by radiologic
technologists. Diagnosis and
treatment also are discussed.
This article is a Directed
Reading. Your access to
Directed Reading quizzes for
continuing education credit
is determined by your area of
interest. For access to other
quizzes, go to www.asrt.org
/store.
After completing this article, readers should be able to:
■
■
■
■
■
■
■
■
■
■
Describe the eye’s anatomy and functions.
Differentiate between visual acuity and visual field.
List and describe types of visual impairments.
Discuss and describe the cause, treatment and prevention of retinopathy of prematurity.
Describe and differentiate between causes of childhood vision impairment.
List common causes of sports, workplace and combat eye injuries.
Discuss and describe the cause, symptoms and treatment of retinal detachment.
Discuss and describe age-related ophthalmic diseases and their treatments.
Understand the effect of new imaging modalities on vision care.
Apply patient management skills to patients with vision impairments.
P
hysiologically, sight occurs
when the eyes and brain
work together to detect,
translate and interpret
incoming visible spectrum
electromagnetic radiation. Emotionally,
sight means much more to us. Along
with touch, sound and smell, sight connects us to our external surroundings.
Sight gives us the awe-inspiring pleasure
of experiencing the vastness and grandeur of the Grand Canyon and allows us
to stand safely by the rim’s edge.
All animals use body language to
communicate. Flattened ears, an arched
back and raised hackles are unmistakable signs of a cat’s anger and aggression. Humans smile and make eye
contact as a nonverbal way to tell others
that we are friendly and interested.
Adequate vision is fundamental to
quality of life. We rely on this sense to
read, work with our hands, respond to
smiles or quiet tears and to navigate.
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
For those of us who see, with or without
glasses, it is hard to imagine all the ways
our lives would change if we were blind.
An interview with Arthur Schreiber
enriched this author’s perception of
sight and blindness. He is chairman of
the New Mexico Commission for the
Blind in Albuquerque, New Mexico,
and he was interviewed to obtain suggestions for techniques radiologic technologists can use to help their patients
who are visually impaired or blind.
In 1969, Mr Schreiber, a longtime
leader of the radio and television
broadcast industries, had the first of 16
surgical procedures to repair bilateral
detached retinas. Blind since 1982,
Mr Schreiber now relies on adaptive
computer technology to read, write,
keep up with e-mail correspondence
and interact with websites. He is looking forward to getting a PenFriend
audio labeler (Royal Institute of Blind
People, London, England) so he can
565
.CE
. . . . . . . . . . . . . . . . . . . . . . . . . . .......................................................................
OCULAR DISORDERS
identify the contents of his kitchen cabinets
and refrigerator.
Mr Schreiber stated that it is important to
“learn how to live as a blind man” before getting the technology. To that end, he spent 6
months at the New Mexico Commission for
the Blind Orientation Center in Alamogordo,
New Mexico, where he learned independent
living skills. Later, he graduated from an assistive technologies program at the Veterans
Administration Rehabilitation Center for the
Blind in Tucson, Arizona. Now aged in his
early 80s, Mr Schreiber laments that older people with sight impairments give up too easily.
“Going blind is a nuisance, but it isn’t the end
of the world,” he said (oral communication,
February, 15, 2009).
Anatomy of the Eye
Figure 1. Eye anatomy.
The eye often is compared to a camera.
Both the eye and the camera have a pupil or
aperture that controls the amount of light entering
the internal area. A lens focuses the light onto a photosensitive surface. In the case of a digital camera, this
is a light-sensitive coupling device. For the eye, it’s the
retina. Both types of light-sensitive surfaces convert
incoming light into electrical code.
However, the eye is smarter than a camera. Unlike
special camera settings, which take into account the
amount of available light, motion and distance, the eye
automatically accommodates for these variables. Once
received and translated in the retina, encoded input
travels through the optic nerve to the brain where it is
converted into the image that we see.
Although small, the eye is a complex organ (see
Figure 1). The average human eye is approximately
2.54 cm wide and deep and 2.3 cm high.1 The sclera, a
tough outer covering, both maintains the shape of the
eye and, along with facial bones and fat, provides protection. Six muscles attached to the sclera move the eye
and allow us to see in different directions without having to move our head. The choroid, a distinct vascular
layer located between the sclera and the retina, delivers
oxygen and other nutrients to the retina. Changes in
this layer can affect retinal integrity and compromise
vision. The cornea, a transparent portion of the sclera,
allows light to enter the eye.
The iris, the colored portion of the eye, is a musclecontrolled diaphragm that opens and closes around the
pupil. Pupil diameter can range from approximately
566
2 mm in very bright light to 8 mm under dim conditions.1 The ciliary body is attached to the lens and contracts and relaxes, thus changing the lens shape so that
it can focus incoming light onto the retina.
Two fluid-filled spaces within the eye provide additional protection and maintain the internal pressure.
The aqueous humor, located between the cornea and
the lens, helps inflate the eye, moves nutrients and
waste products in and out of the eye and contributes
to corneal optical properties. The vitreous body is
the large part of the eye behind the lens. It contains a
gelatinous material (the vitreous humor) that both fills
space and holds the retina in place. Unlike the aqueous
humor, which is constantly replenished, the contents of
the vitreous chamber remain constant.1
The retina is a multilayered tissue that covers the
back of the eye. The outermost layer, the retinal pigment epithelium, protects and covers a layer of lightsensitive cells just beneath it. These specialized photoreceptor cells, the rods and cones, detect light energy
and convert it into electrical impulses that travel along
the optic nerve to the brain.
The rods, located primarily along the retinal periphery, are sensitive to low-intensity light and permit vision
under dimly lit conditions. Rod cells do not respond to
or distinguish between colors. The cone cells produce
sharp images and color vision. However, cone cells,
less light sensitive than rod cells, require more intense
light. This is why we see less detail and do not perceive
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .CE
...
DIRECTED READING
color at twilight. The cone cells are located within the
macula or the central portion of the retina. A shallow
depression located in the center of the macula, the
fovea, contains the highest concentration of cone cells.2
Therefore, it is especially important that retinal treatments conserve macular integrity.
The bottom retinal layers connect the rods and
cones to specialized nerve cells that facilitate intercellular communication, fine-tune retinal sensitivity and act
as a conduit between the retina and the optic nerve.
Located just medial to the fovea is the optic disc.
Here, millions of retinal nerve cells converge at the optic
nerve origin. Because the optic disc does not contain
photoreceptors or other retinal structures, it is a “blind
spot” in the visual field. We usually are not aware of a
visual hole because continuous eye movements allow the
brain to fill in the missing information.2
eye and focus it onto the retina. However, a combination
of factors such as eye length and physical and chemical
changes to the cornea, lens and the internal fluids can
cause light to miss the retina.4 When this happens, the
patient has a refractive error and requires corrective
glasses or contact lenses to see clearly.
When the eye is too long, light focuses before it
reaches the retina. This condition is myopia. People
with myopia, or nearsightedness, have difficulty seeing distant objects and words. In the reverse situation,
when the eye is too short, light does not focus by the
time it reaches the retina. This is called hyperopia or
farsightedness and impairs near vision.4
Astigmatism, an irregularly shaped cornea, produces blurred vision at any distance. People who have
astigmatism also may be nearsighted or farsighted.
Corrective lenses to adjust focus or surgery to improve
the corneal contour can correct astigmatic vision.5
Types of Vision Impairment
Vision impairment involves loss of visual acuity or
loss of visual field not restored with corrective lenses,
medical treatment or surgery.
Visual acuity refers to the ability to see objects clearly. Trauma, infections, amblyopia, retinopathy, nearsightedness and farsightedness are a few of the many
causes for visual acuity loss.3
The World Health Organization defines impaired
vision as a visual acuity between 20/70 and 20/200 with
the use of corrective lenses. A person who has 20/70
vision can resolve at 20 ft what a person with 20/20
vision can resolve at 70 ft. The threshold for blindness
or “legally blind” status is a central vision acuity of
20/200 in the better eye following the best possible correction.3
Visual field, the ability or inability to see from side to
side or up and down without moving the eyes or turning
the head, is another way to describe vision and vision
impairment. A normal visual field is approximately 160°
to 170° in the horizontal plane. People who have a visual
field of 20° or less also are considered legally blind.
Trauma and conditions such as multiple sclerosis and
optic nerve compression can cause visual field loss.3
Refraction and Refractive Errors
Refraction refers to changes in the velocity and
direction of light as it travels through one medium and
contacts another. When the eye is the medium through
which light travels, anatomical structures such as the tear
film, cornea, lens and the liquids contained within the
aqueous and vitreous humors direct light through the
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
The Lens and Vision Impairment
Biochemical changes to the lens and associated
structures cause 2 commonly encountered vision
impairments. Presbyopia, the inability to focus on small
and close objects, is the result of age-related changes to
the lens and associated muscles. Corrective lenses help
improve close-up vision.
Cataracts, another type of age-related visual impairment, are caused by opacities that develop within the
crystalline structure of the lens. Replacing a patient’s
lens with an artificial lens restores clear vision. A fixedfocus intraocular lens is the most common type of lens
transplant. Wearers of fixed-focused lenses may still
require glasses or contacts to have clear distance or
near vision. Multivision intraocular lenses, although
available, are an option most patients do not choose
because the results might not be as good (Robert
Avery, MD, University of New Mexico Hospital ophthalmologist, oral communication, February 8, 2010).
Aqueous and Vitreous Humors and Vision Impairment
The aqueous and vitreous humors serve different
functions. The aqueous humor, which fills the volume
between the cornea and lens, contains protein, glucose
and lactic and ascorbic acids dissolved in water. An
equilibrium between aqueous humor production by the
ciliary processes and outflow through the trabecular network maintains a balanced flow of nutrients, oxygen and
waste products in areas that lack a direct blood supply.
A balance between aqueous humor production and outflow maintains normal intraocular pressure. Glaucoma
567
.CE
. . . . . . . . . . . . . . . . . . . . . . . . . . .......................................................................
OCULAR DISORDERS
occurs when there is increased production or decreased
outflow of aqueous humor. Untreated, high intraocular
pressure damages the optic nerve and causes blindness.
The vitreous humor fills the space between the
lens and the retina. Unlike the aqueous humor, the
vitreous humor is static and does not move in and
out of the eye. Salts, sugars, collagen, collagen fibers
and hyaluronic acid make up the vitreous humor,
which positions the retina and presses it against the
choroid layer. Problems such as retinal detachment
occur when the vitreous humor liquefies or pulls away
from the retina. Age-related changes to the vitreous
humor produce floaters. These roaming spots and
fibers are usually more of an annoyance than a source
of impaired vision (Dr Avery, oral communication,
February 8, 2010).
Retinopathy
Retinopathy is a nonspecific term associated with
noninflammatory retinal pathology. There are 2 retinopathy categories: simple or nonproliferative retinopathies and proliferative retinopathies.6 Presence of
cotton wool spots — identified by white patches in the
retina and bleeding into the eye — is an example of a
simple retinopathy. Nonproliferative retinopathy may
resolve without treatment.7
Proliferative retinopathies, the more serious
form of the disease, involve the growth of new and
abnormal blood vessels that may bleed into the vitreous humor or tug on the retina and cause a retinal
detachment. Diabetes and being born before 27
weeks’ gestation are 2 proliferative retinopathy
risk factors.7
In the United States, the rate of premature births
is nearly 13%, or more than 540 000 premature births
per year.9 Of these, 48 000 infants will die and nearly
100 000 of the surviving babies will have lifelong disabilities.10 In European countries and other developed
nations, the preterm rate ranges from 5% to 9%.
The reasons for the higher incidence of premature
births in the United States are unclear, but infertility
treatments that increase the odds of twins or higher
multiple births are implicated. Other causes may
include the use of labor-inducing medications and
cesarean deliveries before fetuses reach term.9
Recently, the American College of Obstetricians and
Gynecologists (ACOG) revised its guidelines on when to
induce labor. According to the ACOG report, conditions
such as gestational or chronic hypertension, preeclampsia, eclampsia, diabetes, early rupture of membranes,
severe fetal growth restriction and post-term pregnancy
are acceptable reasons to induce labor. However, some
conditions, such as a transverse fetal position and placenta previa, make labor induction too risky.11
Infants born after 24 to 25 weeks of gestation often are
mature enough to survive outside the womb (see Table 1).
However, these small babies require prolonged and intensive care in specialized neonatal units. Infants < 30 to 33
weeks’ gestation face a myriad of medical challenges that
range from persistent ductus arteriosus and intracranial
hemorrhage to infections, intestinal inflammation and
the apnea and bradycardia associated with having immature respiratory and nervous systems (see Table 2).
Nearly one-half of all extremely premature infants
develop lifelong cognitive and physical disabilities that
range from cerebral palsy and hearing loss to learning
disabilities, asthma, poor vision and blindness.13
Premature Birth and Vision
Premature birth puts infants at added risk for mortality throughout childhood, as well as at risk for many
lifelong conditions, such as behavioral and learning
disorders. Premature infants are also more likely to
have vision problems such as strabismus, amblyopia,
myopia and retinopathy of prematurity (ROP).
Premature infants are those who are born before 37
weeks’ gestation. There is no identifiable cause for most
premature births. However, there are many risk factors associated with having a premature birth. Mothers
who have had a premature infant have a 20% to 40%
increased risk for having another premature birth.
Other risks associated with a premature birth include
multiple gestation pregnancies, preeclampsia, diabetes
and maternal malnutrition.8
568
Retinopathy of Prematurity
When an infant has ROP, abnormal vasculature
tugs and pulls on the retina and ultimately may cause
the retina to detach from the underlying vascular bed
(Allison Livingston, MD, neonatologist, University of
New Mexico Hospitals, Albuquerque, New Mexico, oral
communication, January 6, 2010).
ROP usually develops in both eyes and primarily affects newborns weighing < 1250 g or those born
before 31 weeks’ gestation.14
The disorder affects more than 70% of newborns
who are born before 27 weeks’ gestation and decreases
in incidence and severity as gestational age increases.15
ROP is one of the most common causes of childhood
visual impairment and blindness.
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .CE
...
DIRECTED READING
Table 1
Prematurity and Outcome12
Weeks of Gestation
Likelihood of Survival (%)
23
17
24
39
25
50
26
80
27
90
28-31
90-95
32-33
95
34+
Almost as likely as full-term
introduction of antibiotics and incubators began
helping save the lives of very small premature babies.
During the 1940s and 1950s, retrolental fibroplasia, or end-stage ROP, became the single largest
cause for infant vision impairment and blindness.17
Researchers estimate that more than 12 000 infants
who may not have otherwise survived became
blind as a consequence of the oxygen therapy they
received (Chantal Boisvert, OD, MD, pediatric ophthalmologist, University of New Mexico Hospitals,
Albuquerque, New Mexico, oral communication,
January 19, 2009). It took many years of concerted
effort before researchers around the world connected
and confirmed the link between the oxygen therapy
that preterm babies received and abnormal retinal
vascularization.17
Increased incidence of ROP is directly related to
the enhanced ability to save the lives of younger newborns. Recent research findings show that in addition
to prematurity, low birth weight and high oxygen concentration, the following risk factors also contribute
to ROP:
■ Poor postnatal weight gain.
■ Decreases in maternally derived insulin-like
growth factors.
■ Ethnicity.18
Newborns are not born with ROP; the condition
develops during the first few weeks following an early
birth. For reasons that are not yet completely understood, early exposure to the environment outside the
womb causes the immature vessels that supply blood
to the retina to grow in a tangled and disorganized
fashion. Abnormal vascularization often resolves without treatment or affecting vision. However, for some
babies, ROP progresses and can cause the retina to
detach from its supporting layers.16
Approximately 28 000 of the nearly 4 million
infants born each
year in the United
Table 2
States weigh less than
Premature Infant Characteristics
1250 g. Of these,
Weeks
Observations
Physiologic Characteristics
14 000 to 16 000
Gestation
will have ROP.
24
Eyes fused, thin translucent skin,
Lungs – no air sacs
Fortunately, 90%
high water loss, poor muscle tone,
Brain – gyrus and sulcus beginning to
of these infants
ears floppy, weight 700-1000 g
form
have mild ROP that
Nervous system – little myelination
resolves without treatVascular system – fragile vasculature
ment. However, some
Immune system – immature
infants require interventional treatment
28
Eyes open, skin less translucent,
Lungs beginning to mature, low surfacand about 500 of
high water loss, poor muscle tone,
tant
those with ROP severe
ears floppy, weight 1000 g
More brain development
enough for treatment
Better myelination and vascularization
have some degree of
Immature immune system
visual impairment
32
Fine hairs covering skin, better
Better lung function
or become legally
muscle
tone,
weight
1500-1600
g
Better nerve-muscle coordination
blind.14
Improved immunologic responses
ROP did not exist
Source:
oral
communication,
Allison
Livingston,
MD,
neonatologist,
University of New Mexico,
until the mid-20th
Albuquerque, NM, January 6, 2009.
century when the
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
569
.CE
. . . . . . . . . . . . . . . . . . . . . . . . . . .......................................................................
OCULAR DISORDERS
the baby cannot respond to directions, the
ophthalmologist uses a sterile probe to move
the eye. According to Dr Boisvert (January
2009), “screening makes the biggest impact
on preventing vision loss and blindness.”
Observing the location, amount and progression of abnormal retinal blood vessel
growth determines ROP severity (see Figure
3 and Table 3).20 In addition to abnormal
vascular growth, the presence of dilated
veins and tortuous arteries or “plus disease” increases risk for retinal scarring and
detachment. Plus disease can occur as early
as stage 2 ROP.21
Treatment
Cryosurgery was the first surgical method
available to physicians to slow or stop the
progression of ROP. Touching an ultracooled
probe along prescribed areas of the sclera
Figure 2. A pediatric ophthalmologist uses an indirect hand-held ophthalmodestroys the vessels growing along the outer
scope (1.15 X) to evaluate retinopathy of prematurity (ROP) progression in an
edge of the retina.22 Although this technique
infant born at 24 weeks of gestation. The baby, now 42 weeks gestational age, has
stage II ROP that is beginning to resolve without treatment. Photo by the author.
has been shown to reduce peripheral vision,
it spared the central portion of the retina and
preserved the vision of nearly 53% of infants
Diagnosis
who underwent cryotherapy.23
Because ROP takes several weeks to develop, infants
Peripheral laser ablation is the current method used
who have a birth weight of less than 1500 g, a gestato treat stage 2 and 3 ROP or stage 1 ROP accompational age of less than 30 weeks or both receive ROP
nied by plus disease (Dr Boisvert, oral communication,
screening at 31 weeks
or 4 weeks after
Table 3
birth — whichever is
Description of Retinopathy of Prematurity by Location and Stage14
19
later (Dr Boisvert,
Location
Stage
Description
oral communication, January 12 and
Zone I – center of the retina
1
Mildly abnormal blood vessel growth, resolves
19, 2009). To screen
without treatment or causing visual impairment
infants for ROP, the
Zone II – midregion of retina
2
Moderate abnormal blood vessel growth, most
ophthalmologist first
cases resolve without treatment or causing
uses eye drops to
visual impairment
anesthetize the baby’s
Zone
III
–
retina
periphery
3
Abnormal blood vessel growth toward the ceneyes. A binocular
ter
of the eye; many babies require treatment
indirect ophthalmoto prevent retinal detachment
scope, consisting of
a light attached to
4
Partially detached retina; babies require treata headband and a
ment
hand-held lens, per5
Completely detached retina; babies require
mits visualization of
treatment to preserve vision
the vitreous humor
Adapted
from:
Retinopathy
of
prematurity.
www.nei.nih.gov/health/rop/rop/asp.
Accessed October
and the retina (see
31, 2009.
Figure 2). Because
570
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .CE
...
DIRECTED READING
Figure 3. To record ROP progression, the ophthalmologist draws and describes examination observations.
January 12, 2009). Laser damage lowers the localized
oxygen requirement and thereby inhibits the synthesis
of vascular endothelial growth factor (VEGF), which
stops abnormal vascular proliferation (Dr Boisvert, oral
communication, January 12 and 19, 2009). Some rare
ROP laser ablation side effects include corneal burns,
abnormal eye pressure, bleeding into the eye and cataracts. However, this procedure preserves vision for most
infants who require ROP treatment.
Clinicians are now investigating the use of anti-VEGF
compounds to treat ROP. VEGF usually orchestrates
normal vascular development, responds to injuries by
stimulating new vascular growth and creates collateral
circulation to bypass blocked vessels. Because certain
cancers also stimulate VEGF production to support
tumor growth, anti-VEGF drugs are an important cancer treatment strategy.24 Clinical trials are underway to
determine whether the off-label use of anti-VEGF drugs
such as pegaptanib sodium, ranibizumab and bevacizumab are effective and safe ROP treatments.25
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
Childhood Ophthalmic Diseases
According to the Vision 2020 report, the prevalence
of childhood blindness in affluent countries such as
the United States is 3 per 10 000 children aged 0 to
15 years. In developing nations, the number of blind
children is 15 per 10 000 children aged 0 to 15 years.26
Compared with the frequency and impact of other
childhood diseases, the number of blind children is
relatively low. However, these children face a lifetime
of blindness, along with the associated developmental,
social and economic effects of their disability. Vision
2020 states that up to 80% of the world’s causes of
blindness are avoidable. The main causes of preventable or treatable blindness are26 :
■ Corneal scarring – Africa and some parts of Asia.
■ Cataracts – worldwide.
■ Glaucoma – worldwide.
■ Retinopathy of prematurity – affluent nations.
■ Congenital abnormalities – worldwide.
■ Refractive errors – worldwide.
571
.CE
. . . . . . . . . . . . . . . . . . . . . . . . . . .......................................................................
OCULAR DISORDERS
The diagnosis and treatment of childhood ocular
diseases often requires the attention not only of pediatricians, but of specialists such as ophthalmologists,
occupational therapists and pediatric ophthalmologic
surgeons accustomed to working with infants and children. Radiologic technologists also play an important
role when very young children require medical imaging
procedures to diagnose retinal cancer and to monitor
treatment. Infants and children are not simply small
adults. Therefore, the equipment and techniques used
to diagnose and treat pediatric vision problems must
accommodate differences in body type and size and
the child’s ability to follow directions and cooperate.
Timely treatment is another important factor. Many
clinicians describe a “window of opportunity” in treating pediatric ocular diseases. For some diseases, such
as strabismus and amblyopia, missing the window of
opportunity, or period in which it is still possible to
reestablish brain-eye communication pathways, may
result in permanently impaired vision or blindness.
Strabismus
Strabismus is a common childhood vision problem, affecting nearly 4% of children younger than 6
years old. Strabismus is a neuromuscular condition
that causes the eyes to align in different directions.27
Sometimes called “crossed eyes” and “wall eyes,” strabismus occurs when the parts of the brain that influence eye movement or the muscles that control ocular
motion do not work properly.28
Strabismus is not just a cosmetic issue. Strabismus
impairs 3-D vision and depth perception and affects the
child’s physical and cognitive development. The brain
ignores the distorted information received from the misaligned eye and eventually the brain permanently loses
the ability to respond to optic nerve information.28 To
prevent loss of sight in the weaker eye, it is important to
diagnose and treat strabismus while the brain still can
recognize and respond to visual stimuli. In most cases,
children should receive treatment before age 6 years.
A strabismus diagnosis usually is made during a
well-child checkup, when the pediatrician observes that
light reflected from the pupil is not in the same location in each eye. Friends and family also may notice the
child’s eyes do not appear straight.
Strabismus treatment depends on numerous factors, such as the child’s age, medical condition, ability
to follow directions and tolerance for medical procedures.28 Treatment may include one or more of the
following strategies28 :
572
■ Corrective glasses with or without prisms to help
with focusing.
■ Atropine eyedrops to blur vision in the good eye
and thereby strengthen the weaker eye.
■ An eye patch to cover the dominant eye and force
use of the weaker eye.
■ Eye exercises to strengthen and improve eye muscle flexibility.
■ Surgery to realign the eyes.
Amblyopia
When a child has amblyopia, the brain does not recognize information received from the eye.29 “Lazy eye”
is another name used to describe amblyopia. However,
many clinicians say “lazy brain” is a more accurate
description of this condition.
Approximately 1% to 3% of healthy children and
more than 5% of children who have other vision
problems, such as ROP, also may have amblyopia. All
newborns have poor eyesight at first, but during the
course of normal growth and development, vision
matures and improves. However, if vision quality is not
well balanced, such as when one eye is notably more
farsighted than the other, the brain suppresses distorted signals and vision pathways to the brain do not
develop normally. If not treated in time, the child will
become functionally blind in that eye. Other eye conditions can promote the amblyopic condition29 :
■ Strabismus.
■ Cataracts.
■ Extreme differences in refractive errors.
■ Drooping eyelid.
Unlike strabismus, amblyopia is not accompanied by
easily observed signs, such as the eyes pointing in different directions. Because the child is not aware of having a weak eye, there is no way for the parents to know
there is something wrong. The possibility of undetected
amblyopia emphasizes the importance of having regular vision evaluations.
Evaluating differences in refractive index, or retinoscopy, can reveal whether one eye is extremely farsighted or nearsighted compared with the other eye.
Although retinoscopy does not confirm a diagnosis of
amblyopia, it can raise the possibility that the brain is
suppressing vision in the weaker eye.29 For children old
enough to reliably follow directions, an examination
using a simple eye chart may reveal vision supression.
Treatment may include prescription glasses to correct and reestablish balanced vision. Other treatments
include wearing a patch over the stronger eye and
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .CE
...
DIRECTED READING
orthoptic treatment, in which the child performs eye
exercises to force activity in the amblyopic eye.
Improvement in vision depends on the severity and
type of amblyopia, as well as the child’s ability to comply
with treatment. Amblyopia treatment is most effective
when treatment begins before a child is 7 years old.29
Retinoblastoma
With only 300 to 350 new cases in the United States
each year, retinal cancer, or retinoblastoma, is a rare
disease that affects 1 in every 15 000 to 30 000 infants.
Although retinoblastoma most often is diagnosed during
infancy, children up to 6 years old also can develop retinal cancer.30 Most retinoblastoma cases are spontaneous
and do not appear to have genetic origins. Spontaneous
retinoblastoma tends to affect one eye and has a cure
rate approaching 95%.31 Although the reasons are
unclear, subtle sequence changes in chromosome 13 are
an associated retinoblastoma risk factor.
One in 10 children who have retinoblastoma has a
relative who also had the disease. Inheritance is autosomal dominant, which means if only one parent has
the disease, a couple’s offspring have a 25% risk of
inheriting retinal cancer. Retinoblastoma of genetic
origin tends to affect both eyes, has a somewhat lower
cure rate, and increases risk for developing other cancers later in life.
People who have hereditary retinoblastoma do not
make a protein that regulates normal retinal cell division.32 Unlike sporadic forms of the disease in which
there is a single retinal tumor, the retinas of children
who have the familial cancer contain many tumors.33
Sporadic retinoblastoma also increases retinal
cancer risk for the next generation. Every time an
adult with sporadic retinoblastoma has a child, the
chance of that child also having retinal cancer is 7%
to 15%. 32 Genetic testing and genetic counseling are
available for families who are concerned about the
likelihood of passing this cancer on to their children. Infants and children who have a family history
of retinoblastoma should receive regular screening
examinations by an ophthalmologist. Starting shortly
after birth, these evaluations involve using eyedrops
to anesthetize and dilate the eye to assess the eye
using an indirect ophthalmoscope. For more detailed
information, the ophthalmologist may request that
the patient undergo an ultrasound, magnetic resonance (MR), or computed tomography (CT) procedure. Each of these medical imaging techniques
can help confirm the presence of retinal tumors and
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
reveal whether there is a tumor outside of the eye or
in the brain. 32
Parents are sometimes the first to notice the most
important sign of retinoblastoma — family photographs show a white pupil rather than the “red eye”
reflection that the camera flash normally produces.
Looking similar to a cat’s eye at night, the reflection
of light off the tumor surface is a sign called leukocoria. Other signs may indicate retinoblastoma as well as
many less serious and more common eye conditions32 :
■ Strabismus.
■ Eye pain or redness.
■ Eye swelling.
■ Different colored irises.
Children who have inherited retinoblastoma
are also at risk for developing pineal gland tumors.
Therefore, regular follow-up MR or CT exams until
the child is 5 or 6 years old play an important role in
providing patients with early detection and lifesaving
treatment options.34
Staging to determine whether the cancer has spread
within the eye or to other parts of the body helps assess
the likelihood of retaining vision while still providing
effective tumor treatment. The simplest staging system
divides retinoblastoma into 3 groups35 :
■ Intraocular – tumor contained within the eye.
■ Extraocular or orbital – tumor present in the eye
socket.
■ Metastatic – tumor has spread to other parts of
the body.
The International Classification for Intraocular
Retinoblastoma, another cancer staging rubric, takes
into account the likelihood of preserving vision (see
Table 4). Regardless of stage and the potential for preserving vision, current treatments cure almost all children who have intraocular retinoblastoma.35
Retinoblastoma treatments can range from laser
photocoagulation for small tumors to various types
of radiation therapy to treat more extensive cancers.
Examples of radiation treatment strategies include:
■ Intensity-modulated radiation therapy.
■ Stereotactic radiation therapy.
■ Proton beam radiation therapy.
■ Plaque brachytherapy.
Many patients also receive chemotherapy. Highintensity heat and cold are other commonly used treatment methods.34 Enucleation, a treatment for the most
severe cases, removes the eye and part of the optic
nerve and does not preserve vision. It can, however, cure
children who have large or many intraocular tumors.32
573
.CE
. . . . . . . . . . . . . . . . . . . . . . . . . . .......................................................................
OCULAR DISORDERS
Table 4
International Classification for Intraocular
Retinoblastoma35
Group
Description
A
Tumors < 3 mm, confined to retina and distant
from central region
B
Other tumors, < or > 3 mm, confined to retina,
close to center of vision
C
Well defined tumors, some spread to areas
under the retina or to the vitreous humor
D
Large, poorly defined tumors, considerable
spread to areas under the retina or vitreous
humor, retinal detachment
E
Tumor size, location, or spread indicates low
chance of preserving vision
Adapted from: How is Retinoblastoma Staged? www.cancer
.org/docroot/CRI/content/CRI_2_4_3X_How_is_retinoblastoma
_staged_37.asp. Accessed January 20, 2010.
Left untreated, retinoblastoma is almost always fatal.
However, survival is more than 90% for patients whose
disease was detected and treated early and most of these
children retain vision in one or both eyes.33
Ophthalmic Trauma
Every year in the United States, eye injuries cause
nearly 1 million people to go to hospital emergency
departments for care.36 Sports and workplace-related
accidents are the leading cause of monocular blindness
and visual impairment. Most eye injuries are preventable and occur in people younger than 30 years old.37
Combat-related injuries are another cause of vision
impairment among this age group.
Blunt impacts, chemical burns, corneal abrasions,
penetrating foreign bodies, lacerations, orbital fractures
and traumatic brain injury can cause problems that
range from a black eye to significant visual impairment
and blindness. Signs and symptoms of a potentially serious eye injury include38 :
■ Vision loss.
■ Bleeding.
■ Lacerations.
■ A foreign body inside the eye.
Sports Injuries
According to the American Academy of Ophthalmology, sports and other recreational activities cause
574
more than 40 000 eye injuries each year.39 Basketball
and baseball, followed by racket and water sports, cause
the majority of eye injuries when a ball, racket or an
elbow hits the face.
Mild blunt trauma often produces a black eye and
bleeding from the small veins located near the surface of the eye. These injuries are not serious, and
usually do not cause permanent damage. However,
forceful blunt trauma can cause bleeding between
the cornea and the iris, fracture the orbital bone
and also may damage the retina and optic nerve.38
Injuries from shattered glass and BB pellets, although
less common, are examples of sports-related penetrating injuries.
Workplace Injuries
The Occupational Safety and Health Administration
(OSHA) estimates that 1000 work-related eye injuries
occur each day. In addition to the personal toll on workers and their families, work-related accidents produce
more than $300 million per year in lost productivity,
medical expenses and worker compensation.40
A Bureau of Labor Statistics study showed that flying or falling objects cause nearly 70% of workplace
accidents. Chemical burns and impact with swinging objects, such as tree limbs, chains and ropes, are
other frequent causes of workplace eye injuries.40
To prevent workplace eye injuries, OSHA requires
that employers provide workers with appropriate eye
protection equipment. However, studies show that
many workers do not receive the training and information needed to match the working condition with
the eyewear that provides sufficient protection.40
Combat-related Injuries
Eye injuries and traumatic brain injuries (TBIs)
that can affect vision are taking an unexpectedly
high toll on U.S. troops serving in Afghanistan
and Iraq. According to a study reported at a recent
joint meeting between the American Academy of
Ophthalmology and the Pan-American Association of
Ophthalmology, eye damage constitutes 10% to 13%
of all serious wounds that require evacuation from
the war zone.41 Brain injuries and injuries that require
limb amputations have long been the focus of wartime
medical care. However, the U.S. Army reports that
at times serious eye wounds occur at nearly twice the
rate of injuries that require amputation.
Army physicians have stated that roadside bombs,
grenades and other mortar attacks that send hundreds
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .CE
...
DIRECTED READING
of flying shrapnel
Table 5
fragments into the air
Ultrasound and Ocular Trauma42
often are the cause
Ocular Condition
Ultrasound Finding
of penetrating eye
wounds. Although all
Normal eye
Circular hypoechoic structure
Army and Marine perGlobe rupture
Decreased globe size, anterior chamber collapse, sclera bucksonnel wear eye proling
tection, blast impact
Intraocular foreign body
Bright echogenic acoustic profile, shadowing/reverberation vitrecan shatter protective
ous artifacts
eyewear, strip it from
the head, or even
Dislocated lens
Dislocated from its normal anterior position
implode it into the
Retinal detachment
Hyperechoic undulation
face. The army reports
Elevated intracranial
Average optic nerve sheath diameter > 5 mm
that blast effects, such
pressure
as changes in atmospheric pressure and
Vitreous hemorrhage
Echogenic material in posterior chamber
the secondary shock
Adapted from: Ultrasound Guide for Emergency Physicians. www.sonoguide.com/smparts_ocular.html.
wave that harm soft tis- Accessed April 20, 2010.
sues, cause 80% of all
eye injuries.37,40
lens dislocation and retinal detachment to intraocular
A recent Rand Corporation study showed that 320
foreign bodies (see Table 5).36
000, or nearly 30% of U.S. combat troops, received
Because changes in the eye may indicate changes in
some degree of TBI caused by blast exposure.
other parts of the body, optic nerve sheath swelling and
Research is just beginning to show the relationship
edema also can indicate elevated intracranial pressure.
between subtle blast-related TBIs and post-traumatic
Therefore, an ED ultrasound assessment can provide
stress disorder. However, the relationships between
evidence that indicates a brain injury or a spontaneous
blast exposure, TBI and impaired vision are largely
brain bleed and the need for emergency imaging with
unknown. 37
other modalities and appropriate care.36,42
Early study results indicate blast injury, in addition
Using portable ultrasound equipment with a
to causing easily observed penetration and rupture
high-frequency (7.5 to 10 MHz or higher) linear
damage, also can affect binocular vision, visual acuarray transducer and a water-soluble conducting gel
ity and visual field. Research currently is underway to
enables radiologic technologists to conduct an eye
determine the best method to screen, treat and rehaexamination on ED patients. Although patients can
bilitate soldiers who have compromised vision from a
be examined in nearly any position, supine positionblast-related injury.37
ing makes for easier scanning. Usually patients do not
require anesthesia. 36
Ultrasound and Ocular Trauma
Before scanning, the sonographer should remove any
In the emergency department (ED), medical imagbandages or other eye coverings and instruct the patient
ing for ocular trauma presents several challenges:
to close the eyes and imagine looking at a distant point
■ Difficulty in getting ophthalmologic consultation.
to minimize eye movement. To reduce corneal distortion
■ Diagnosis and treatment delays caused by overand the potential for injuring the eye further, it is imporscheduled CT scanners.
tant to limit the pressure on the eye.37
■ Ferrous metal wound contamination and
36
Using sufficient ultrasound gel eliminates an air
MR safety.
interface and improves image quality. Patients com■ Inability to directly visualize intraocular structures
plain when gel seeps into their eyes. However, using less
due to swelling, bleeding and lens opacification.36
gel may necessitate using more pressure to maintain
Acute care providers have found that use of bedside
image quality. Some health care providers find that
ultrasonography can overcome many of these ED chalplacing a thin transparent dressing over the eyelid
lenges. Bedside ultrasonography is an efficient and
maintains patient comfort and image quality.43
cost-effective way to diagnose eye injuries ranging from
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
575
.CE
. . . . . . . . . . . . . . . . . . . . . . . . . . .......................................................................
OCULAR DISORDERS
A
B
Figure 4. A. Color fundus photograph of a 35-year-old man who has type 1 diabetes and early-stage diabetic eye disease. Cotton wool
spots (large white areas) and bleeding (small red spots) can be observed. B. OCT retinal thickness and macular mapping of the same
patient. Note areas of macular edema. Image courtesy of Robert Avery, MD, Department of Ophthalmology, University of New Mexico
Hospital, Albuquerque, NM.
Retinal Detachment
Retinal detachment occurs when a tear or break
in the retina allows vitreous humor fluid to collect
under the retina and separate it from underlying
blood vessels. As a result, detached areas lose their
blood and nutrient supply and no longer function.44
Retinal detachment also can occur without a tear or
a break. Aging and diseases such as macular
degeneration can cause retinal thinning and the
formation of small holes that permit the movement
of fluid behind the retina (see Figure 4 ).44 People at
risk for a detached retina are those who are extremely nearsighted or who have45 :
■ Experienced a previous detachment.
■ A familial history of retinal detachment.
■ Had cataract surgery.
576
■ Inflammatory eye diseases.
■ Had an eye or head injury.
Having diabetes and diabetic retinopathy is
another significant risk factor for a detached retina.
According to a University of Washington study, more
than 7 million people have diabetic retinopathy and
each year 65 000 of them develop sight-threatening
proliferative diabetic retinopathy.46
Over time, the high glucose blood levels and high
blood pressure that often accompany diabetes damage
the small blood vessels that support the retina. At first
some vessels swell, weaken and may leak blood serum
proteins. Other vessels may clog and limit blood flow.
Eventually, new vessels grow, but similar to those that
form as a result of ROP, they are weak, break easily and
bleed. Eventually, these abnormal blood vessels become
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .CE
...
DIRECTED READING
scar-like and pull the retina away from the back of the
eye. Diabetic retinal detachments cause approximately
25 000 people each year to lose their sight.46
Early retinal detachment symptoms include the sudden appearance of:
■ Debris in the field of vision.
■ Flashes of light in one or both eyes.
■ A curtain or shadow over a portion of the visual
field.
■ Blurred vision.
Immediate treatment is necessary. Once the
detachment has progressed, it may not be possible to
restore vision.44
Although patient-reported symptoms are important
for diagnosis, ophthalmologists use various imaging
modalities to see inside the eye and locate detached
areas. An ophthalmoscope, an instrument with a
bright light and a magnifying lens, is a traditional
tool. Ultrasound is another method that is especially
useful when blood in the vitreous humor blocks light
from illuminating the retina. Optical coherence
tomography (OCT), a relatively new imaging modality, is another source of detailed retinal images.
The surgical repair method chosen depends on
the type, location and size of the detachment and the
presence of tears and holes. Laser photocoagulation
and cryopexy are surgical options used when the retinal tear or hole has not yet progressed to the detachment stage. Photocoagulation involves using a lens to
direct laser light to the damaged area. Making small
burns around the hole or tear welds the retina to the
underlying tissue.44
Cryopexy involves anesthetizing the eye and touching an ultracold probe to a location on the sclera
just above the retinal tear or hole. Similar to laser
photocoagulation, cryopexy produces a scar that reattaches the retina to the underlying tissue. Cryopexy is
usually the best option for tears located on the retinal
periphery. Both photocoagulation and cryopexy are
outpatient procedures.44
A common retinal detachment surgery is a scleral
buckle. In this procedure, the surgeon first performs a
cryopexy to repair retinal tears. Stitching a small piece
of silicon sponge or silicon rubber to the sclera creates
a dimple that reduces the tension the vitreous humor
exerts on the retina. When patients have many tears,
the surgeon may opt to make a scleral buckle that
encircles the eye.
Pneumatic retinoplexy, the injection of an expandable gas bubble to push and seal the retina to the back
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
of the eye, is a method used to repair detachments
located in the upper half of the retina. The surgeon
also may perform a photocoagulation or cryopexy procedure to close any retinal tears or holes.43
Age-related Ophthalmic Diseases
Differentiating normal aging processes from conditions in which advancing age combines with genetics,
lifestyle and environmental exposures to increase risk for
vision problems is subtle. Examples of truly age-related
changes are thinning and graying hair, sagging skin and
some alterations in hearing, taste and vision. For other
age-related changes, such as increased incidence of cardiovascular disease and cancer, age is an associated risk
factor, rather than the causal element.
The Special Report on Aging and Vision Loss stated
that “a rapidly increasing proportion of the aging population experience eye problems that make simple daily
tasks difficult or impossible even when wearing glasses
or contact lenses.”47 In the United States, approximately
1.3 million people older than 65 years are legally blind.48
According to a report funded by Prevent Blindness
America, the overall economic impact of age-related
causes of visual impairment and blindness on the individual, caregivers and other health care providers is
approximately $51.4 billion per year. Of this amount,
$35.4 billion reflects the direct and indirect costs of
diabetic retinopathy, cataracts, glaucoma and macular
degeneration.49
Presbyopia
In the United States, 1 of every 11 people self-reports
having blurred near vision or presbyopia. Usually beginning around age 40, this inability to see small print or to
do tasks like threading a needle is caused by age-related
changes that reduce the elasticity and flexibility of the
ciliary muscle and lens. As a consequence, the lens loses
the ability to change from a flat to a roundish shape and
thereby increase the optical power and magnification
needed to focus on near objects. Presbyopia, or poor
accommodation, is nearly universal in people more than
65 years old.50
Presbyopia develops gradually. Some of the first
signs include holding printed material farther away to
improve clarity and blurred vision at normal reading
distance. Although age is the direct cause of presbyopia
for most people, having diabetes, multiple sclerosis, or
cardiovascular disease can make it occur earlier in life.
Use of antidepressants, antihistamines, diuretics and
alcohol also can lead to premature presbyopia.51
577
.CE
. . . . . . . . . . . . . . . . . . . . . . . . . . .......................................................................
OCULAR DISORDERS
A complete eye exam can confirm a presbyopia
diagnosis. Treatments include the recommendation to
purchase over-the-counter reading glasses, or prescription bifocals and gradient lenses. Multifocal intraocular
lenses are an option for some people undergoing cataract surgery.52
There are several types of cataracts. Nuclear cataracts, the most common type of cataract, are the result
of the aging process. These cataracts form in the center
of the lens. Subcapsular cataracts, which begin at the
back of the lens, and cortical cataracts, which form in
the cortex (outer rim), are indirectly related to aging.
People who have diabetes or who take high doses of
steroids are at higher risk for these types of cataracts.56
Cataracts also can form as a result of55 :
■ Eye surgery or having diseases such as glaucoma
and diabetes.
■ Trauma to the eye and head.
■ Congenital cataracts present at birth or those
that develop during childhood.
■ Exposure to infrared light, and electromagnetic
and ionizing radiation.
Radiation-induced cataracts are of particular concern
to radiologic technologists. A 20-year National Institutes
of Health (NIH) cohort study showed that radiologic
technologists, even when taking other risk factors such
as diabetes and smoking into consideration, are at
increased risk for developing cataracts. The authors concluded that ionizing radiation exposures, even those less
than the recommended threshold of 2 Gy, affect the lens
and increase long-term cataract risk.57
Cataracts
An Eye Disease Prevalence Research Group study estimated that more than 20 million people older than 40
years, or nearly 1 in every 5 people living in the United
States, have a cataract in one or both eyes.53 This same study
projected that by 2020, more than 30 million people living
in the United States will have cataracts (see Figure 5).
The expenses associated with cataract treatment
already constitute 60% of all vision-related Medicare
costs. With approximately 1.5 million procedures performed each year in the United States, cataract surgery
is the no. 1 surgical procedure.53 Therefore, demographics on cataracts are an important measure of the
effects of an aging population on medical care and the
Medicare system.
Cataracts form as the result of age-related lens
changes that make the lens less transparent to light.
The lens consists of 3 parts:
■ Capsule.
■ Epithelium.
■ Fibers.
The capsule is a smooth and transparent membrane that surrounds the
lens and helps maintain lens shape and
curvature. The epithelium regulates the
movement of ions, nutrients and water in
and out of the lens. The epithelium also
makes the lens protein fibers that contribute bulk, and because of their crystalline
arrangement, make the lens transparent.54
It is uncertain exactly why the aging
process causes lens fibers to clump and
produce small cloudy areas within the
lens. Some studies indicated that a lifetime of exposure to ultraviolet light may
be the culprit. Other studies showed
that exposure to infrared radiation and
cosmic radiation also may play a role.
Smoking, air pollution, exposure to lead,
diabetes and heavy alcohol consumption
Figure 5. Diagnosing many eye diseases, including cataracts, involves standard
are examples of other lifestyle and envitesting for visual acuity and looking into the patient’s dilated eye with a slit lamp and
ronmental risk factors associated with
hand-held lens. Photo by the author.
increased risk for age-related cataracts.55
578
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .CE
...
DIRECTED READING
Age-related cataracts usually
develop slowly. At first, the cataracts are small and the patient
may not notice changes in image
sharpness. But as the cataracts
develop, clouding reduces the
amount of light that reaches
the retina. Patients may report
having dull or blurry vision and
glare from oncoming headlights
that makes driving at night
difficult. 56 Eventually, as the
cataracts become denser and
the lens increasingly discolored,
the patient finds it difficult or
impossible to read, navigate
safely and differentiate among
colors. 55
Diagnosing cataracts involves
taking the patient’s medical
history, standard testing for
visual acuity and looking into
the patient’s dilated eye with a
Figure 6. To determine the most appropriate intraocular lens implant, an ophthalmologist or
slit lamp and hand-held lens.
ocular technician measures the curvature of the patient’s cornea, anterior chamber depth and
Tonometry measures the intraoc- the distance from the corneal vertex to the retinal pigment epithelium. Photo by the author.
ular pressure to determine
whether the patient also has
glaucoma. Patients also may receive tests to evaluate
Glaucoma
contrast and glare sensitivity, macular function and
Glaucoma usually is caused by abnormally high
specialized examinations to determine whether the
intraocular pressure due to disturbances in either
corneal epithelium can withstand the surgical
the flow or production of aqueous humor. Normal
procedure. 58
intraocular pressure should be < 21 mm Hg. Although
Cataracts are treated with surgery to remove the
researchers have yet to determine the reasons, high
lens and to replace it with an intraocular implant.
intraocular pressure damages the optic nerve and
Because most patients receive fixed-focus intraocular
causes visual impairment and blindness. However, glauimplants, the ophthalmologist will ask the patient
coma may occur with normal or even less than normal
about his or her near and distance vision habits.
intraocular pressure.59
Patients may opt for a distance lens in one eye and
In the United States, more than 2 million people
a close-up lens in the other. Some patients prefer to
aged 40 years and older have glaucoma, and of these,
have distance implants in both eyes and to use readnearly 120 000 are blind. Another 2 million people are
ing glasses for near vision (Dr Avery, oral communicaunaware that they have the disease.60
tion, February 8, 2010).
The economic impact of glaucoma is significant. In
The ophthalmologist then measures the curvature
the United States, glaucoma is the reason for more than
of the patient’s cornea, anterior chamber depth and
7 million physician visits each year. The annual costs of
the distance from the corneal vertex to the retinal
Social Security benefits, lost income tax revenues and
pigment epithelium (see Figure 6). These measuregovernment-funded health care expenses are more than
ments represent the unique optical characteristics of
$1.5 billion.60
the patient’s eye and define the intraocular implant
In addition to age, risk factors associated with havprescription and placement (Dr Avery, oral communiing glaucoma include61:
cation, February 8, 2010).
■ African-American race.
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
579
.CE
. . . . . . . . . . . . . . . . . . . . . . . . . . .......................................................................
OCULAR DISORDERS
■ Other family members who have the disease.
■ Farsightedness or nearsightedness.
■ Diabetes.
■ Long-term use of corticosteroids.
■ Previous eye injury.
Because there are no early symptoms, most people
do not know they have glaucoma until the disease
already has caused damage. Therefore, the annual
eye exam plays an important role in detecting earlystage glaucoma and giving patients the opportunity
to receive timely medical or surgical treatment.
Although it is not possible to regain lost vision, treatment slows disease progression.62 Open-angle glaucoma and angle-closure glaucoma are the 2 most common forms of the disease.63
Open-angle glaucoma is the most common form. As
the name suggests, when people have open-angle glaucoma, the drainage angle formed by the cornea and
the iris remains open. However, as the eye ages, the
microscopic drainage channels within the angle may
become clogged or the eye may overproduce aqueous
fluid. In either case, changes in aqueous humor drainage and production increase pressure within the eye.64
Early symptoms of the disease are uncommon, but
some patients report changes in their peripheral vision.
Patients often state that portions of words are missing
or they have difficulty navigating stairs. Unfortunately,
open-angle glaucoma, also called “a thief in the night”
usually does not produce noticeable vision changes
until there is marked optic nerve damage.
Treatment includes medications such as prostaglandin analogues to reduce aqueous humor production
and laser surgery to open the trabecular meshwork
within the angle.65
In angle-closure glaucoma, the small angle that
remains from the pressure between the cornea and
lens junction does not permit sufficient flow of aqueous humor out of the eye.66 The causes of angle-closure
glaucoma include63 :
■ Congenital defects and the aging process.
■ Head or eye trauma and forward displacement of
the lens.
■ Diabetes and abnormal blood vessel growth.
When the intraocular pressure increases rapidly, it
causes acute angle-closure glaucoma. When this happens, patients experience severe eye pain, nausea and
vomiting, blurred vision, halos around lights and reddening of the eye.66 Acute angle-closure glaucoma is a
medical emergency and without immediate treatment
can cause permanent blindness within a few hours.63
580
There are medical and surgical treatments for
angle-closure glaucoma. Eyedrops containing betablockers, cholinergic drugs or prostaglandin-like
compounds can help reduce the pressure. During an
acute angle-closure emergency, diuretics can quickly
reduce the intraocular pressure. However, surgery is
the standard treatment for angle-closure glaucoma.61
Other types of glaucoma include low-tension or
normal-tension glaucoma, congenital glaucoma and
glaucoma caused by medication side effects or trauma. Low-tension glaucoma causes optic nerve damage
and reduced peripheral vision. Medication can reduce
eye pressure by an additional 30% and slow the disease’s progression for some patients.67
Congenital glaucoma occurs when infants are born
with an eye defect that slows normal fluid drainage.
Symptoms of congenital glaucoma include cloudy eyes,
light sensitivity and excessive tearing. Surgery is the usual
treatment, and if done promptly, prevents vision loss.67
Macular Degeneration
The breakdown of the central part of the retina,
or macular degeneration, is a chronic eye disease that
usually affects people aged 50 years and older.68 The
macula, composed primarily of cone cells, permits
fine detail and color vision. People who have macular
degeneration rely on their peripheral vision for sight.
Although deterioration of the central part of the retina does not cause total blindness, it affects quality of
life by reducing central vision, which makes it impossible to drive and difficult to read, recognize faces
and perform any kind of activity that requires seeing
small details. The deteriorating tissue may or may not
cause bleeding.68
In the United States, more than 13 million people
have early signs of macular degeneration. Of these,
more than 6 million eventually develop the disease.46
Dry macular degeneration involves no bleeding and
is the most common form of the disease. Wet macular
degeneration occurs when new blood vessels grow,
bleed and leak fluid under the macula. Dry macular
degeneration often develops into wet macular degeneration.69 Macular degeneration symptoms include68 :
■ Needing bright light to read or do close work.
■ Difficulty adapting to low-light environments.
■ Blurriness of printed words.
■ Decreased color brightness or intensity.
■ Difficulty seeing faces.
■ Haziness of overall vision.
■ Straight lines appearing wavy.
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .CE
...
DIRECTED READING
Symptoms progress more rapidly with accompanying
Noncontact Ocular Biometric
vascular growth and bleeding.
Technologies
Age is the primary risk factor associated with
Improvements in imaging techniques and computdeveloping macular degeneration. Other risk factors
er
processing
have made it more likely that patients
include68 :
will undergo a medical imaging procedure as part
■ Family history of macular degeneration.
of a routine eye examination or during their course
■ Caucasian race.
of diagnosis and treatment. Noncontact ocular
■ Light-colored eyes.
biometry is the current term used to describe ocular
■ Exposure to sunlight.
imaging modalities that do not require probes or
■ Female sex.
sensors that touch the eye (see Figure 7). In addition
■ Smoking.
to reducing patient anxiety and discomfort, noncon■ Obesity.
tact ocular biometry reduces corneal abrasion and
■ Low blood levels of zinc and antioxidant vitamins.
infection risks and improves anterior ocular meaMacular degeneration may affect one or both eyes.
surements by:
However, the disease usually doesn’t affect lifestyle
■ Eliminating the physical distortion that contact
until dry macular degeneration affects both eyes.
methods may cause.
The deterioration of the retinal pigment epithe■ Using objective assessment standards.
lium and the deposition of resulting byproducts in the
Noncontact ocular biometry technology is office
retina causes macular degeneration.68 The appearance
based,
and designed so that ocular technicians are
of drusen (small, yellowish cellular deposits) in the
often
responsible
for this portion of the patient’s eye
macula on ophthalmoscopic examination is a sign of
68
examination.
Patients’
eyes may or may not require
retinal pigment epithelium breakdown. Angiography
dilation before undergoing a noncontact ocular biomand optical coherence tomography are medical imagetry procedure.
ing procedures used to determine the extent of macular damage.
As vision falters, many people experience hallucinations that include unusual
patterns, geometric shapes and sometimes animals and faces. This is called
Charles Bonnet syndrome. Many patients
do not report these symptoms because
they fear the hallucinations will be associated with mental illness.
There are no treatments to reverse
dry macular degeneration. Stopping or
slowing the progression of vascular proliferation and bleeding are the goals of
wet macular degeneration treatments.
Intraocular injections of antivascular
endothelia growth factor can stop the
growth of new blood vessels, similar to
treatments used to control proliferative retinopathy. Laser photocoagulation is another treatment option for
diseased areas outside of the fovea.
Photodynamic therapy — cold laser
light combined with the light-sensitizing
drug verteporfin — can seal leaking
Figure 7. OCT, technology that is more comfortable for patients than direct conblood vessels and at the same time
tact methods, provides high-resolution images of the retinal layers and other antepreserve foveal rod and cone cells. 69
rior anatomical landmarks. Photo by the author.
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
581
.CE
. . . . . . . . . . . . . . . . . . . . . . . . . . .......................................................................
OCULAR DISORDERS
Ophthalmoscopy and Funduscopy
Ophthalmoscopy, also called funduscopy, involves
focusing light through the patient’s dilated iris to
observe various landmark structures in the patient’s
eye. This part of the eye examination can reveal signs
of many eye diseases, such as cataracts and retinopathy. Fundus photography both improves the level of
observable detail and provides a permanent record of
observed clinical findings.
The fundus camera is a combination light source,
low-powered microscope and camera. Some fundus
cameras require pupil dilation and other models,
called nonmydriatic fundus cameras, do not require
that patients receive eyedrops to relax pupil muscles.
Providing the “bird’s-eye” or en face view of the eye
interior, fundus photography allows the health care
provider to70 :
■ Observe the retina under white light and in full
color.
■ Observe the retina under red-free light to
improve contrast between vessels and other retinal structures.
■ Combine intravenous contrast media with the
visual examination to see circulation abnormalities.
In addition to screening patients for the retinal
changes that precede or accompany disease such as
diabetes and hypertension, fundus photography is a
fast and practical way to document70 :
■ Surgical repair history.
■ Abusive trauma such as shaken baby syndrome.
■ First indications of retinal disease such as drusen
deposits.
Assessment of Intraocular Lens Implants
Because of the high demand for cataract surgery,
patients must be evaluated and treated efficiently
without compromising quality of care. A recent innovation in noncontact ocular biometry now makes it
possible for ocular technicians to quickly determine
patient intraocular implant measurements. The
IOLMaster (Zeiss Medical Solutions, Dublin, Ireland),
can replace several instruments and imaging modalities and measures axial length, anterior chamber
depth and corneal radius in 2 minutes, according to
company literature.
The IOLMaster uses partial coherent interferometry to measure axial length and image analysis
techniques to measure anterior chamber depth and
582
corneal radius.71 Previously, the patient would have
had an ultrasound examination to determine axial
length and anterior chamber depth and either keratometry, videokeratometry or peripheral refraction
to measure the corneal curvature for intraocular
implant measurement.71
The technique does not use dilation. The patient
positions his or her face on the IOLMaster chin rest.
Once the patient focuses on a fixed point, the technician runs the console and uses a joy stick to align the
machine. It takes less than 0.5 seconds to perform
each measurement. The technician aligns the machine
against internal standards, rather than visually determined anatomical landmarks, meaning the values are
objective rather than subjective. Studies have shown
that the technique provides high resolution and repeatable data.71 However, when the laser cannot adequately
penetrate through a large and dense cataract, it is
necessary to use ultrasonography to measure the axial
length and anterior chamber depth (see Figure 8)
(author observation, UNMH ophthalmology clinic,
February 8, 2010).
Optical Coherence Tomography
Optical coherence tomography (OCT) is an interferometric technique that uses near-infrared light to
penetrate light-scattering tissues. Based on differential backscattering of low-coherence laser light (850
nanometers), OCT can resolve individual retinal layers. OCT already has had a considerable effect on the
diagnosis, treatment and monitoring of retinal diseases
such as diabetic retinopathy and macular degeneration72 (see Figure 9).
Many describe OCT as an “optical biopsy” that
provides clinicians with in situ and real-time tissue
cross-sections. Evaluating patients with diabetes for
the first signs of diabetic retinopathy is one of many
important OCT applications. In the case of macular
degeneration, it is now possible to monitor the choroid layer and treat the patient with anti-VEGF before
vessels “sprout through” the retina and cause permanent damage (Dr Robert Avery, oral communication,
February, 2010).
In a recent study involving more than 2000 macular
degeneration patients, researchers at the New England
Eye Center of the Tufts Medical Center in Boston,
Massachusetts Institute of Technology in Cambridge
and the Eye Center at the Pittsburgh School of
Medicine in Pennsylvania compared the diagnostic
and monitoring capabilities of various en face imaging
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .CE
...
DIRECTED READING
Functional Magnetic Resonance
Functional magnetic resonance (fMR) is
primarily a research tool in ophthalmology,
but is beginning to show promise in diagnosis. Similar to positron emission tomography
(PET), fMR is a physiologically based method often described as revealing the brain at
work. Differences in how oxygenated and
deoxygenated blood hemoglobin behave in a
strong magnetic field form the physiological
basis for fMR imaging. Hemoglobin is the
blood protein that carries and deposits oxygen in tissues. Tissues use oxygen to make
the metabolic energy needed to support
physiologic activity. The process of depositing oxygen in metabolically active tissues
produces deoxygenated hemoglobin (dHb)
and changes the molecular shape. Thus,
differences in Hb and dHb become a physiologic surrogate for brain activity.75
As a research tool, fMR provides important
insight into the neurobiology of cognition,
Figure 8. Ultrasonography is used to measure ocular axial length and anterior
memory, emotion, creativity, intelligence and
chamber depth. It is necessary to use ultrasonography to measure the axial length
vision. As a clinical practice tool, clinicians
and anterior chamber depth when the laser cannot penetrate through a large and
are beginning to use fMR to identify epileptic
dense cataract. Photo by the author.
foci and to differentiate schizophrenia from
manic-depressive disorders. Functional MR
technologies, such as color fundus photography, with
studies are an important aspect of mapping the visual
OCT. Using a research prototype ultrahigh-resolution
cortex and other parts of the brain responsible for
OCT machine (3.5 µm axial image resolution operatreceiving and processing visual input. The outcomes of
ing at 25 000 axial scans per second), the researchers
these research efforts are an increasingly refined underwere able to73 :
standing of vision neurophysiology and new ways to help
■ Resolve intraretinal layers.
clinicians preserve or restore sight.
■ Create comprehensive 3-D retinal images.
The use of fMR studies is improving our understand■ Identify early-stage soft drusen deposits associing of how unbalanced vision or untreated strabismus
ated with advanced macular degeneration.
causes amblyopia. Preliminary studies have shown that
■ Identify the small, hard drusen deposits not assoalthough both types of amblyopia reduce the ability
ciated with macular degeneration.
of the visual cortex to respond to stimuli, the reasons
■ Describe the physical distortion drusen deposits
are not the same. Few neurons are active when unbalcause to the contour of the photoreceptor and
anced vision causes brain suppression and blindness.
retinal pigment epithelial layers.
However, when strabismus is the cause of vision loss,
Early glaucoma diagnosis is another important
researchers have not found a close relationship between
application of OCT technology. Glaucoma is charfMR response and vision deficits. This indicates that the
acterized by retinal ganglion cell death and nerve
physiology of blindness caused by unbalanced vision is
fiber layer thinning. Clinicians use OCT to detect
not the same as blindness caused by strabismus.76,77
and monitor changes in the retinal nerve fiber layer
Other vision-related uses of fMR include77,78 :
and to create macular thickness maps. Newer com■ Noninvasive mapping of visual borders within
mercially available OCT models can make 3-D reconthe retina.
structions of the optic nerve head and can resolve 7
■ Presurgical visual cortex mapping.
to 8 µm or better.74
■ Location of deep brain lesions.
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
583
.CE
. . . . . . . . . . . . . . . . . . . . . . . . . . .......................................................................
OCULAR DISORDERS
A
B
Figure 9. A. Optical coherence tomography (OCT), a noncontact ocular biometry method, is used to observe retinal layers and map
macular thickness. The patient is a 60-year-old woman who has normal results. B. OCT also can reveal a spectrum of retinal pathologies, such as the macular holes that compromise vision and increase risk for retinal detachment. Image courtesy of Robert Avery, MD,
Department of Ophthalmology, University of New Mexico Hospital, Albuquerque, NM.
■ Dissecting the physiology of hallucinations, auras
and blind sight, in which people who are functionally blind may perceive color or shapes.
Visually Impaired and Blind Patients in
The Medical Imaging Facility
According to Mr Schreiber of the New Mexico
Commission for the Blind, “blindness is a characteristic and not a medical problem” (oral communication,
February, 15, 2009). It takes a moment to fully appreciate
the subtle implications of his statement. However, upon
further reflection, one quickly understands that for many
patients, the route to visual impairment and blindness is
the medical condition. The outcome, when medical or
surgical treatments are not available or fail, loses much
of its medical significance for both the patient and the
584
patient’s eye doctor (Mr Schreiber, oral communication,
February 15, 2010). He said that “many people don’t get
that” and they also “don’t understand how to help people
who are vision impaired or are blind.”
Like all patients who enter a medical imaging
facility, people who have vision impairment need to
feel comfortable and safe. Helping patients navigate
a new and different environment, providing instructions concerning clothing and jewelry removal, as
well as instructing the patient on positioning for the
exam and what sounds or sensations to expect, is
something radiologic technologists do for all patients.
However, when a patient cannot see, clear and understandable oral instructions are especially important.
It is also important to add touch to patient communication and management.
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .CE
...
DIRECTED READING
A
B
C
Figure 10. A. Locking arms can
make navigating through doors and
other narrow passageways difficult.
B. A light touch allows the blind
person to follow and anticipate movements. C. A light shoulder touch
accommodates differences in height.
Photos by the author.
Mr Schreiber suggested that a health care provider or a family member accompany the patient from
the waiting room to the imaging area. When doing
so, the escort should ask the patient whether help is
needed. Because of a complexity of issues pertaining to stigma and denial, many patients, particularly
those who are older, will not ask for assistance. Mr
Schreiber also stated that touching or grabbing the
patient without warning can be disorienting and
frightening.
Once introduced, it is helpful to ask the patient
to take your arm. The best way to present your arm
is by bending it across your abdomen so the patient
can touch your elbow. If you are considerably shorter
than the patient, ask him or her to place a hand on
your shoulder (see Figure 10).
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
This light-touch method
allows the patient to follow
your path and anticipate
your movements, and prevents navigation problems
when making turns or
passing through a narrow
door. Provide warning of
an upcoming turn, stairway or door by announcing
the approaching hazard.
Dropping your bent arm is
the signal for a narrow passageway. If the patient uses a
cane, position yourself so the
patient’s free hand is next
to you.
Once the patient is ready
to undergo the procedure,
you should carefully explain
what the patient:
■ Needs to do.
■ May feel or hear.
■ Can do if feeling ill or
frightened.
Mr Schreiber suggested
that allowing patients to run
their hands over the equipment can improve orientation
and make it easier for you to
position them.
Balance, especially in
unfamiliar surroundings,
can pose extra challenges for
people who are visually impaired or blind. Therefore,
to prevent falls, it is important that the radiologic
technologist give clear place and placement clues to
orient the patient. It is also helpful to provide the
patient with something to hold on to, or to act as a
referencing touch.
The Eyes — A Window to Your Health
People have long believed that the eyes can reveal
personality attributes, such as honesty, kindness and
maternal attentiveness. Although the truth of these
beliefs is not testable, researchers are finding compelling scientific evidence that a thorough eye examination can uncover a patient’s risk for stroke and cardiovascular disease or determine whether a diagnosis of
Alzheimer disease is in the patient’s future.79
585
.CE
. . . . . . . . . . . . . . . . . . . . . . . . . . .......................................................................
OCULAR DISORDERS
Research clinician Professor Tien Wong of the Centre
for Eye Research, University of Melbourne in Australia,
uses ophthalmoscopy and fundus photography to screen
patients for early signs of cardiovascular disease. Wong
has stated that changes in retinal blood vessels represent
what is happening in the rest of the body, particularly in
the brain, kidneys and heart.
After collecting fundus photography data from
more than 20 000 patients, Wong and his research
team found a correlation between observable abnormalities in retinal vasculature and the patient’s risk
of eventually having a stroke or heart attack. Some
of the abnormalities include arteries that cross over,
compress and nick veins, dilated and swollen veins
and the presence of cotton wool spots. Wong attributed minute cholesterol deposits and inflammation
as the causal factor in vascular compression, dilation
and swelling. Loss of blood flow within the retina
produces white cotton wool spots. According to Wong,
people who have cotton wool spots are 8 to 10 times
more likely to have a stroke.79
Devising ways to identify the subtle signs of early
Alzheimer disease and other dementias is another
topic of active research. Currently, a brain biopsy and
a postmortem histological evaluation are the only ways
to confirm a diagnosis and differentiate between types
of dementia. The benefits of an early diagnosis are
controversial because of issues pertaining to treatment,
long-term care and insurance coverage. However, having this information gives patients the opportunity to
take medications to slow disease progression and to
arrange for future needs.
Professor M Francesca Cordeiro of the Department
of Ophthalmology, University College London, in
England, uses a fluorescent tag and a laser ophthalmoscope to observe Alzheimer-related retinal damage. Dr
Cordeiro’s research involving specially bred Alzheimer
mice showed a direct correlation between retinal cell
death and brain cell death. She hopes these findings
will lead to simple screening tests for Alzheimer and
other neurodegenerative diseases.80
Dr Lee Goldstein, a Boston University researcher
and clinician, is taking a different tack in developing an
early Alzheimer disease diagnostic. Taking clues from
the observation that mice with Alzheimer disease often
develop bilateral cataracts, Goldstein delved further
and discovered that Alzheimer cataracts are different
— both in location and composition — from typical
age-related cataracts. Located in the lens periphery,
Alzheimer cataracts do not interfere with vision. Unlike
586
age-related cataracts, Alzheimer cataracts are composed
of ␤-amyloid protein, the same material that composes
Alzheimer brain tangles.81
Goldstein and colleagues already have developed a
noninvasive way to detect ␤-amyloid protein buildup in
the lens that precedes cataract formation. Goldstein,
a psychiatrist and neurologist, cites the importance of
patients receiving medication well before the emergence of obvious cognitive decline to slow disease progression and preserve quality of life.81
References
1. Bianco C. How vision works. Howstuffworks.com. http
://health.howstuffworks.com/eye1.htm. Accessed January
26, 2010.
2. Martini FH. Fundamentals of Anatomy and Physiology. 4th ed.
Upper Saddle River, NJ: Prentice Hall; 1998.
3. Vision impairment. Centers for Disease Control and
Prevention. www.cdc.gov/ncbddd/dd/ddvi.htm. Published
October 29, 2004. Accessed February 1, 2010.
4. Haddrill M. Refractive errors and refraction: how the eye
sees. All About Vision website. www.allaboutvision.com
/eye-exam/refraction.htm. Accessed January 31, 2010.
5. Astigmatism. American Optometric Association. www.aoa
.org/Astigmatism.xml. Accessed January 31, 2010.
6. Fishman FA. Retinopathy. Answers.com. www.answers
.com/topic/retinopathy. Accessed November 11, 2009.
7. Fishman FA. Retinopathies health article. www.healthline
.com/galecontent/retinopathies. Published 2002. Accessed
November 16, 2009.
8. Premature Babies. Keepkidshealthy.com. www.keepkid
shealthy.com/Newborn/premature_babies.html. Updated
November 10, 2001. Accessed November 18, 2009.
9. Grady D. Premature births are fueling higher rates of infant
mortality in U.S., report says. The New York Times website.
www.nytimes.com/2009/11/04/health/04infant.html.
Published November 3, 2009. Accessed November 5, 2009.
10. Fight for preemies [video online]. March of Dimes website. www.marchofdimes.com/prematurity/. Accessed
November 19, 2009.
11. ACOG issues revision of labor induction guidelines [press
release]. www.acog.org/from_home/publications/press_
releases/nr07-21-09.cfm. Released July 21, 2009. Accessed
November 5, 2009.
12. March of Dimes releases premature birth report card for
U.S.: nation gets a “D” [article adapted from press release].
www.medicalnewstoday.com/articles/129225.php. Published
November 13, 2008. Accessed November 19, 2009.
13. Dennison JA. Extremely premature babies often face a lifetime of disability. Daily News Central website. http
://health.dailynewscentral.com/content/view/270/63.
Published January 7, 2005. Accessed November 19, 2009.
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .CE
...
DIRECTED READING
14. Retinopathy of prematurity. National Eye Institute website. www.nei.nih.gov/health/rop/index.asp. Accessed
October 31, 2009.
15. Preidt R. Eye problems increasing in preemies. www
.medicinenet.com/script/main/art.asp?articlekey=115251.
Accessed May 12, 2010.
16. Video of Dr Thomas Lee from The Vision Center at
Children’s Hospital Los Angeles using Bioptigen handheld
OCT scanner to treat retinopathy in premature babies
[online video]. Optical Coherence Tomography News
website. www.octnews.org/articles/1150915/video-of-drthomas-lee-from-the-vision-center-at-c/. Published May 10,
2009. Accessed January 4, 2010.
17. Patz A. The role of oxygen in retrolental fibroplasia. Trans
Am Ophthalmol Soc. 1968;66:940-985.
18. Heidary G, Lofqvist C, Mantagos I, et al. Retinopathy
of prematurity: clinical insights from molecular studies.
Neoreviews. 2009;10:550-557.
19. Screening examination of premature infants for
retinopathy of prematurity. National Guideline
Clearinghouse. www.guideline.gov/summary/summary
.aspx?ss=15&doc_id=8713&nbr=4846. Published 2006.
Accessed January 4, 2010.
20. Diagnosis of retinopathy of prematurity. Aboutkidshealth
.com. www.aboutkidshealth.ca/PrematureBabiesDiagnosis
-of-Retinopathy-of-Prematurity-ROP.aspx?articleID=7782&
categoryID=PI-nh2-05e. Reviewed July 12, 2006. Accessed
December 15, 2009.
21. Eye conditions: retinopathy of prematurity. University of
Michigan Kellogg Eye Center wesbite. www.kellogg.umich
.edu/patientcare/conditions/retinopathy.prematurity
.html. Accessed January 12, 2009.
22. Freeze treatment reduces blindness in premature infants
[press release]. National Eye Institute website. www.nei
.nih.gov/news/pressreleases/roppressrelease.asp. Released
March 29, 1988. Accessed January 11, 2009.
23. Study confirms value of treatment to prevent blindness in
premature babies [press release]. National Eye Institute
website. www.nei.nih.gov/news/pressreleases/041496.asp.
Released April 14, 1996. Accessed January 11, 2009.
24. What is Avastin? Genentech USA website. www.avastin
.com/avastin/patient/crc/avastin/what/index.m. Accessed
January 12, 2009.
25. Pan-VEGF blockade for the treatment of retinopathy of
prematurity (BLOCK-ROP). ClinicalTrials.gov. http
://clinicaltrials.gov/ct2/show/NCT00702819. Received
June 19, 2008. Accessed January 12, 2009.
26. Vision 2020 – the right to sight. www.vision2020.org/main
.cfm?type=IDX. Accessed January 25, 2010.
27. My child has strabismus and amblyopia. Children’s
Hospital Boston website. www.childrenshospital.org/az
/Site1644/mainpageS1644P0.html. Accessed January
24, 2010.
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
28. Davidson T, Haggerty M. Strabismus. Encyclopedia of
Children’s Health website. www.healthofchildren.com/S
/Strabismus.html. Accessed January 23, 2010.
29. Swartout-Corbeil DM, Steefel L. Amblyopia. Encyclopedia
of Children’s Health. www.healthofchildren.com/A
/Amblyopia.html. Accessed January 24, 2010.
30. What are the key statistics for retinoblastoma? American
Cancer Society website. www.cancer.org/docroot/CRI
/content/CRI_2_4_1X_What_are_the_key_statistics_for_
retinoblastoma_37.asp?sitearea=. Revised October 26,
2009. Accessed January 13, 2010.
31. Isidro M, Roque MR, Aaberg TM. Retinoblastoma.
eMedicine website. http://emedicine.medscape.com
/article/1222849-overview. Updated January 21, 2009.
Accessed January 20, 2010.
32. Abramson DH, Servodidio C. A parent’s guide to understanding retinoblastoma. Retinoblastoma.com. http
://retinoblastoma.com/retinoblastoma/frameset1.htm.
Accessed January 19, 2009.
33. Genes and disease: retinoblastoma. National Center for
Biotechnology Information website. www.ncbi.nlm.nih
.gov/bookshelf/br.fcgi?book=gnd&part=retinoblastoma.
Accessed January 4, 2010.
34. Retinoblastoma treatment. National Cancer Institute
website. www.cancer.gov/cancertopics/pdq/treatment
/retinoblastoma/patient/allpages/print. Accessed January
20, 2010.
35. How is retinoblastoma staged? American Cancer
Society website. www.cancer.org/docroot/CRI/content
/CRI_2_4_3X_How_is_retinoblastoma_staged_37.asp.
Updated October 26, 2009. Accessed January 20, 2010.
36. Grimm L, Carmody KA. Bedside ultrasonography, ocular
evaluation. eMedicine website. http://emedicine.med
scape.com/article/1401982-overview. Updated March 6,
2009. Accessed April 20, 2010.
37. Cockerman GC, Goodrick GL, Weichel ED, et al. Eye and
visual function in traumatic brain injury. J Rehabil R D.
2009;46(6):811-818. www.rehab.research.va.gov
/jour/09/46/6/cockerham.html. Accessed February
5, 2010.
38. Sports eye injuries. University of Illinois at Chicago
department of ophthalmology and visual sciences website.
www.uic.edu/com/eye/LearningAboutVision/EyeFacts
/SportsEyeInjuries.shtml. Updated August 31, 2005.
Accessed February 5, 2010.
39. Eye injuries in sports. American Academy of Family
Physicians website. http://familydoctor.org/online/famdo
cen/home/healthy/physical/injuries/794.html. Updated
December 2009. Accessed February 5, 2010.
40. Eye Protection in the workplace. Oklahoma State
University Environment Health and Safety website. http
://ehs.okstate.edu/training/oshaeye.htm. Accessed
February 5, 2010.
587
.CE
. . . . . . . . . . . . . . . . . . . . . . . . . . .......................................................................
OCULAR DISORDERS
41. Zoroya G. House focusing on eye injuries in combat
bill. USA Today website. www.usatoday.com/news
/washington/2007-10-03-eyes_N.htm. Updated October 4,
2007. Accessed February 5, 2010.
42. Adhikari SR. Ultrasound guide for emergency physicians.
American College of Emergency Physicians Section on
Emergency Ultrasound. www.sonoguide.com/smparts_
ocular.html. Accessed April 20, 2010.
43. Roth KR, Gafni-Pappas G. Unique method of ocular
ultrasound using transparent dressings [published online
ahead of print January 23, 2010]. J Emerg Med. www.jemjournal.com/article/S0736-4679(09)00899-3/abstract.
Accessed April 20, 2010.
44. Retinal detachment. Mayo Clinic website. www.mayoclinic
.com/health/retinal-detachment/DS00254. Published
November 6, 2008. Accessed February 13, 2010.
45. Retinal detachment. National Eye Institute website. www
.nei.nih.gov/health/retinaldetach/retinaldetach.asp.
Reviewed October 2009. Accessed February 13, 2010.
46. Statistics on blindness and blinding diseases in the
United States. University of Washington department of
ophthalmology website. http://depts.washington.edu/oph
thweb/statistics.html. Updated January 1, 2004. Accessed
February 13, 2010.
47. Special report on aging and vision loss. American
Foundation for the Blind website. www.afb.org/Section
.asp?SectionID=15&DocumentID=4423. Published
September 2008. Accessed November 1, 2009.
48. Legally blind. Health and Wellness. www.associatedcon
tent.com/article/2964196/legally_blind.html?cat=5.
Accessed May 12, 2010.
49. Vision problems in the United States. Prevent Blindness
America. www.preventblindness.net/site/DocServer
/VPUS_report_web.pdf?docID=1322. Published 2002.
Accessed December 2, 2009.
50. Presbyopia may affect more than 1 billion worldwide.
The Medical News website. www.news-medical.net
/news/2008/12/08/43896.aspx. Published December
2008. Accessed February 7, 2010.
51. Presbyopia. Mayo Clinic website. www.mayoclinic.com
/health/presbyopia/DS00589. Published May 8, 2009.
Accessed February 7, 2010.
52. Haddrill M. Crystalens and accommodating intraocular
lenses for cataract surgery. All About Vision website. www
.allaboutvision.com/conditions/accommodating-iols.htm.
Accessed February 7, 2010.
53. Carpenter J. Daunting demographics. Cataract
Outsourcing website. www.cataractoutsourcing.com
/featured-healthcare-articles/daunting-demographics
/. Published July 29, 2008. Accessed February 8, 2010.
54. Andley UP. Crystallins in the eye: function and pathology.
Prog Retin Eye Res. 2006;26(1):78-98.
55. Cataract. National Eye Institute website. www.nei.nih.gov
588
56.
57.
58.
59.
60.
61.
62.
63.
64.
65.
66.
67.
68.
69.
70.
71.
/health/cataract/cataract_facts.asp. Reviewed September
2009. Accessed September 22, 2009.
Lee J, Bailey G. Cataracts. All About Vision website. www
.allaboutvision.com/conditions/cataracts.htm. Accessed
February 2, 2010.
Chodick G, Bekiroglu N, Hauptmann M, et al. Risk of
cataract after exposure to low doses of ionizing radiation:
a 20-year prospective cohort study of US radiologic technologists. Am J Epidemiol. 2008;168(6):620-631.
Diagnosing cataracts. Lighthouse International website.
www.lighthouse.org/about-low-vision-blindness/vision
-disorders/cataract/diagnosing-cataracts/. Accessed
February 9, 2010.
Heiting G, Haddrill M. Glaucoma. All About Vision website. www.allaboutvision.com/conditions/glaucoma.htm.
Accessed October 10, 2009.
Glaucoma Research Foundation. Learn about glaucoma.
Glaucoma Research Foundation website. www
.glaucoma.org/learn/. Accessed December 22, 2009.
Glaucoma. The Merck Manuals online Medical Library
website. www.merck.com/mmhe/sec20/ch233/ch233a
.html#. Reviewed August 2008. Accessed February
4, 2010.
About glaucoma. National Glaucoma Research website. www
.ahaf.org/glaucoma/about/. Accessed December 22, 2009.
Spaeth GL. What is angle-closure glaucoma? Glaucoma
Service Foundation to Prevent Blindness website. www
.willsglaucoma.org/aclose.htm. Accessed October 10, 2009.
Open angle glaucoma. Vision Rx website. www.visionrx
.com/library/enc/enc_oaglaucoma.asp. Accessed
December 22, 2009.
Primary open-angle glaucoma. www.merck.com/mmpe
/sec09/ch103/ch103b.html. Reviewed August 2008.
Accessed December 22, 2009.
Glaucoma. Mayo Clinic website. www.mayoclinic.com
/health/glaucoma/DS00283. Published July 17, 2008.
Accessed December 12, 2009.
Facts about glaucoma. National Eye Institute website.
www.nei.nih.gov/health/glaucoma/glaucoma_facts.asp.
Reviewed September 2009. Accessed October 10, 2009.
Dry macular degeneration. Mayo Clinic website. www
.mayoclinic.com/health/macular-degeneration/DS00284.
Published August 26, 2008. Accessed February 16, 2010.
Wet macular degeneration. Mayo Clinic website. www
.mayoclinic.com/health/wet-macular-degeneration
/DS01086. Published August 26, 2008. Accessed February
16, 2010.
Fundus camera. Wikipedia. http://en.wikipedia.org
/wiki/Fundus_camera. Accessed February 21, 2010.
Santodomingo-Rubido J, Mallen EAH, Gillmartin B,
Wolffsohn JS. A new non-contact optical device for ocular
biometry. Br J Ophthlamol. 2002;86(4):458-462. www
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .CE
...
DIRECTED READING
72.
73.
74.
75.
76.
77.
78.
79.
80.
81.
.ncbi.nlm.nih.gov/pmc/articles/PMC1771084/. Accessed
February 23, 2010.
Wolffsohn JS, Peterson RC. Anterior ophthalmic imaging.
Clinical and Experimental Optometry. 2006;89(4):205-214.
Chen Y, Vuong LN, Liu J, et al. Three-dimensional ultrahigh
resolution optical coherence tomography of age-related
macular degeneration. Opt Express. 2009;17(5):4046-4060.
Lin SC, Singh K, Jampel HD, et al. Optic nerve head
and retinal nerve fiber layer analysis: a report by the
American Academy of Ophthalmology. Ophthalmology.
2007;114(10):1937-1949.
Shagam JY. Functional magnetic resonance imaging.
Radiol Technol. 2007;78(6):476MR-489MR.
Choi MY, Lee KM, Hwang JM, et al. Comparison between
anisometropic and strabismic amblyopia using functional magnetic resonance imaging. Br J Ophthalmology.
2001;85(9):1052-1056.
Miki A, Haselgrove JC, Liu GT. Functional magnetic resonance imaging and its clinical utility in patients with visual
disturbances. Surv Ophthalmology. 2002;47(6):562-579.
Miki A, Liu GT, Modestino EJ, et al. Functional magnetic resonance imaging of the visual system. Curr Opin
Ophthalmol. 2001;12(6):423-431.
Eyes: windows to your health. Australian Broadcasting
Corporation website. www.abc.net.au/catalyst/stories
/s1790185.htm. Published November 16, 2006. Accessed
February 21, 2010.
Scientists can spot retinal cell death, predict Alzheimers.
www.tgdaily.com/general-sciences-features/45498-eye-testfor-alzheimers-on-the-way. Accessed May 12, 2010.
Goldstein L. The eyes have it. American Federation for
Aging Research website. http://websites.afar.org/site
/PageServer?pagename=IA_feat47. Published December
2006. Accessed February, 21, 2010.
for answering even more questions and their willingness to
add a few minutes to their busy day to perform some of the
procedures mentioned in the article on the author as part of
her research. Finally, the author wishes to thank the patients
who graciously accepted her intrusion.
Reprint requests may be sent to the American Society of
Radiologic Technologists, Communications Department,
15000 Central Ave SE, Albuquerque, NM 87123-3909, or
e-mail [email protected].
©2010 by the American Society of Radiologic Technologists.
Janet Yagoda Shagam, PhD, is a medical and science
writer and a regular contributor to Radiologic Technology.
In addition to freelance writing, she teaches writing workshops at the University of New Mexico, the University of New
Mexico School of Medicine and the Max Planck Institute
in Göttingen, Germany. Dr Shagam is a member of the
National Association of Science Writers and the Association of
Healthcare Journalists.
The author wishes to acknowledge University of New
Mexico Hospitals (UNMH) ophthalmologists Robert Avery,
MD, and Chantal Boisvert, MD, and neonatologist Allison
Livingston, MD, for the opportunity to meet with patients and
watch procedures and for their patience in answering innumerable questions. The author also wishes to thank UNMH ophthalmology technicians Sharon Romero and Laura Sanchez
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
589
Directed Reading Continuing Education Quiz
#10804-01
Expiration Date:
August 31, 2012*
Approved for 1.5
Cat. A CE credits
Diagnosis and Treatment
Of Ocular Disorders
To receive Category A continuing education credit for this Directed Reading, read the preceding article and circle
the correct response to each statement. Choose the answer that is most correct based on the text. Transfer your
responses to the answer sheet on Page 596 and then follow the directions for submitting the answer sheet to the
American Society of Radiologic Technologists. You also may take Directed Reading quizzes online at www.asrt.org.
Effective October 1, 2002, new and reinstated members are ineligible to take DRs from journals published prior to
their most recent join date unless they have purchased a back issue from ASRT. Your access to Directed Reading
quizzes for Continuing Education credit is detemined by your area of interest. For 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.
1.
The _______ delivers oxygen and other nutrients
to the retina.
a. choroid
b. pigment epithelium
c. lens
d. vitreous humor
2.
Which photoreceptor cells are sensitive to lowintensity light?
a. cone
b. blind spot
c. rods
d. macular
3.
The area of the retina that contains the highest
concentration of cone cells is the:
a. optic disc.
b. periphery.
c. blind spot.
d. fovea.
4.
A person who has 20/60 vision:
a. can resolve at 20 feet what a person who has
20/20 vision can resolve at 60 feet.
b. can resolve at 60 feet what a person who has
20/20 vision can resolve at 20 feet.
c. has reduced vision field.
d. is legally blind.
5.
When the eye is too long:
a. light focuses on the back side of the retina.
b. the patient has an astigmatism.
c. the patient has hyperopia.
d. the patient has myopia.
6.
The role of the aqueous humor is to:
a. cushion the retina.
b. maintain a balanced flow of nutrients and
waste products in areas that lack a direct
blood supply.
c. focus light on the appropriate location in the
retina.
d. reduce intraocular pressure.
Continued on next page
590
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
Directed Reading Continuing Education Quiz
7.
8.
9.
In the most general sense, what is retinopathy?
a. deposits of drusen
b. opacities in the lens
c. retinal diseases that do not involve inflammatory processes
d. floating fibers
The rate of premature births in the United States
is lower than in Europe.
a. true
b. false
Retinopathy of prematurity (ROP) primarily
affects newborns weighing < _______ g or those
born before _______ weeks’ gestation.
a. 1000; 36
b. 1250; 36
c. 1000; 31
d. 1250; 31
10. Which of the following statements is true
concerning ROP?
a. Newborns have ROP at birth.
b. ROP is caused by low oxygen therapy.
c. ROP develops during the first few weeks
following birth.
d. Even as the disease progresses, the retina
remains intact.
11. _______ is the presence of dilated veins and
tortuous arteries.
a. Astigmatism
b. Vitreous humor
c. Diabetic retinopathy
d. Plus disease
12. Rare side effects of ROP laser ablation include:
1. cataracts.
2. corneal burns.
3. bleeding into the eye.
a.
b.
c.
d.
1 and 2
1 and 3
2 and 3
1, 2 and 3
13. A white reflection in a child’s eye in a photograph
may indicate:
a. amblyopia.
b. retinoblastoma.
c. strabismus.
d. a sports-related injury.
14. The most common cause of workplace eye
injuries is:
a. flying or falling objects.
b. chemical burns.
c. impact from an elbow or other body part.
d. imploded protective eyewear.
15. Early study results indicate that blast injury may
affect:
1. peripheral vision.
2. visual acuity.
3. visual field.
a.
b.
c.
d.
1 and 2
1 and 3
2 and 3
1, 2 and 3
Continued on next page
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
591
Directed Reading Continuing Education Quiz
16. On ultrasonography, a bright, echogenic profile
indicates that the patient has a(n) _______ .
a. globe rupture
b. retinal detachment
c. displaced lens
d. intraocular foreign body
17. During ultrasonography for ocular injury, the
sonographer can reduce corneal distortion and
potential for further eye injury by:
a. limiting pressure on the eye.
b. using less gel than normal.
c. speeding up the exam.
d. adding a thick dressing over the eye.
18. The collection of vitreous humor fluid under the
retina causes _______ .
a. glaucoma
b. retinal holes
c. retinal detachment
d. amblyopia
19. According to a University of Washington study,
more than _______ million people have diabetic
retinopathy.
a. 1
b. 4
c. 7
d. 10
20. Seeing flashes of light in one or both eyes is a
symptom of _______ .
a. retinal detachment
b. glaucoma
c. presbyopia
d. retinoblastoma
21. What causes presbyopia?
a. opacities in the lens
b. age-related changes that reduce the flexibility
of the ciliary muscle and lens
c. a retina that is too far away from the lens
d. the brain’s inability to respond to visual
stimulation
22. _______ surgery is the surgical procedure
performed most each year in the United States.
a. Corneal contour
b. Cryo
c. Cataract
d. Eye alignment
23. Radiologic technologists are at added risk for
cataracts.
a. true
b. false
24. Open-angle glaucoma usually does not produce
noticeable vision changes until there is marked
_______ .
a. optic nerve damage
b. blurred close-up vision
c. reduced intraocular pressure
d. amblyopia
25. Acute angle-closure glaucoma is:
a. painless.
b. a condition in which there is insufficient flow
of aqueous humor.
c. usually resolved without treatment.
d. not a medical emergency.
Continued on next page
592
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
Directed Reading Continuing Education Quiz
26. Which of the following is true concerning macular
degeneration?
a. It causes total blindness.
b. It severely reduces central vision.
c. The lens deteriorates in patients with the
disease.
d. Incidence is rare.
27. The appearance of drusen in the macula signifies:
a. retinal pigment epithelial breakdown.
b. bleeding.
c. proliferative retinopathy.
d. nutrient deficiencies.
28. Which of the following is true concerning
treatment of dry macular degeneration?
a. Surgery is the preferred treatment.
b. Most physicians prescribe special eyedrops.
c. Laser ablation can restore most of a patient’s
sight.
d. There are no treatments to reverse dry macular degeneration.
30. The axial length, anterior chamber depth and
corneal radius are measurements needed to:
a. fit patients with intraocular lens implants.
b. diagnose cataracts.
c. monitor macular degeneration.
d. determine retinoblastoma stage.
31. _______ is an interferometric technique that uses
near-infrared light to penetrate light-scattering
tissues.
a. Optical ultrasonography
b. Optical coherence tomography (OCT)
c. Ophthalmoscopic examination
d. Fundus photography
32. The physiological basis for functional magnetic
resonance imaging is:
a. how sound waves resonate through tissues.
b. differences in how oxygenated and deoxygenated hemoglobin behave in a strong magnetic
field.
c. the deposition of radioactive tracers.
d. the relative number of voxels per slice.
29. Advantages of noncontact ocular biometry
include:
1. reduced patient anxiety.
2. reduced risk of infection.
3. no risk of physical distortion of the eye.
a.
b.
c.
d.
1 and 2
1 and 3
2 and 3
1, 2 and 3
For your convenience, the evaluation and answer
sheet for this Directed Reading now immediately
follow the quiz. Just turn to Pages 595 and 596.
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
593
Log on.
Take Quiz.
Score!
Take Your Directed Reading Quizzes Online Anytime!
www.asrt.org/myasrt
It’s Easy To Start:
 Visit www.asrt.org/myasrt.
 Log in.
 Select My Directed Readings.
 Select the answer sheet.
essentialeducation
Printed answer sheets are now located after the quiz questions.
These can be mailed to ASRT at the address on the answer sheet.
See Pages 564 and 596.
©2010 ASRT. All rights reserved.
✁
Carefully cut or tear here.
...........................................................................................................
ON THE JOB
Pathogens on Image Receptors
Hospital-acquired infections or
R.T.(R), is an assistant profesnosocomial infections cause major illsor in the radiologic sciences
ness and death in our inpatient populaprogram at Northwestern State
tion. Not only do these infections take
University in Shreveport,
a toll on patients’ health and increase
Louisiana.
their hospital stays, but they also take a
Becky Britt, MSRS,
serious economic toll on patients and
R.T.(R)(M), is an assistant
hospitals. Although the bacteria that
professor and coclinical coorcause these infections vary, the leading
dinator for the radiologic scicause of hospital-acquired infections is
ences program at Northwestern
Staphylococcus aureus. Historically,
State University in Shreveport,
penicillin-based antimicrobial drugs
Louisiana.
have been used to combat these infections, but bacteria have become resisThe authors thank Matthew
tant to these drugs over time.
Britt, M.T., for performing the
Resistance to penicillin and newer
laboratory tests for this study.
narrow-spectrum ␤-lactamase-resistant
penicillin antimicrobial drugs (eg,
methicillin, oxacillin) appeared soon
after they were introduced into clinical
practice in the 1940s and 1960s.1 By the
late 1960s, > 80% of community- and
hospital-aquired S aureus were resistant
to penicillin. Recent reports suggest that
the evolution and spread of methicillinresistant S aureus (MRSA) seem to follow
a similar wavelike emergence pattern.2
Contact contamination with MRSA
and other infection-causing bacteria
presents a significant problem in the
radiology department. Image receptors
or x-ray cassettes
are handled by
multiple technologists daily.
Without proper
hand sanitizing
and cleaning of
the cassettes,
bacteria that
cause infections
can live on inanimate objects for
days depending
on the type of
bacteria. Several
studies have demonstrated how
Figure 1. At hospital No. 1, MRSA was isolated from the
contaminated
operating room image receptor. The image receptor from the
emergency department contained several other types of bacteria. equipment in the
Ben D Wood, MSRS,
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
hospital causes infections in patients.3-5
The Centers for Disease Control’s handwashing guidelines recommend that
hands be washed after every patient;
unfortunately, health care workers have
demonstrated a low compliance rate.6
The same recommendation of cleaning
after each patient should apply to image
receptors or radiographic cassettes in
radiology. Some of the clinically relevant pathogens that can live on dry
inanimate surfaces include the following
organisms7 :
■ Haemophilus influenzae. Life span:
12 days.
■ MRSA. Life span: 7 days to 7
months.
■ Escherichia coli. Life span: 1.5 hours
to 16 months.
■ Streptococcus pyogenes. Life span: 3
days to 6.5 months.
■ Salmonella typhimurium. Life span:
10 days to 4.5 years.
Methods
This study examined the presence of
nosocomial-infection causing bacteria on
image receptors in the radiology departments of 4 major hospitals in northwest
Louisiana. Samples were gathered using
a random sampling technique from 4
different image receptors at 4 health care
institutions, for a total of 16 samples.
The image receptors were swabbed using
Amies transport medium. The specimens
then were cultured to routine, nonselective microbiology isolation media as well
as MRSA-selective media. The cultures
were allowed to grow for 48 hours.
Results
All 4 health care institutions sampled
had imaging receptors containing bacteria that can cause nosocomial infections, including MRSA, bacillus species,
coagulase-negative staphylococci, grampositive diptheroid bacilli, Enterococcus
species and gram-negative bacilli (see
Figures 1-4). Of the 4 facilities, 1 had
an imaging receptor that contained the
597
...........................................................................................................
ON THE JOB
Figure 2. At hospital No. 2, various gram-negative bacilli,
such as Pseudomonas, were isolated. No MRSA was isolated
in this sample.
Figure 4. At hospital No. 4, the isolated organisms were
coagulase-negative staphylococci, gram-negative bacilli and
gram-positive diptheroid bacilli. No MRSA was identified.
References
Figure 3. At hospital No. 3, coagulase-negative staphylococci
were isolated on all 4 image receptors. No MRSA was isolated.
MRSA pathogen. That image receptor was being used
in the operating room.
Conclusion
Most nosocomial pathogens can persist on inanimate surfaces for weeks or even months, and can
thereby be a continuous source of transmission if no
regular preventive surface disinfection is performed.
Preventing nosocomial infections by hand washing and
cleaning image receptors can reduce patient morbidity
and mortality, decrease the perpetuation of antibioticresistant strains of bacteria and ultimately lead to
decreased health care costs. ◆
598
1. Lowy FD. Antimicrobial resistance: the example of
Staphylococcus aureus. J Clin Invest. 2003;111(9):1265-1273.
2. Klein E, Smith D, Laxminarayan R. Hospitalizations
and deaths caused by methicillin-resistant Staphylococcus
aureus, United States, 1999-2005. Emerg Infect Dis.
2007;13(12):1840-1846.
3. Boyce JM, Potter-Bynoe G, Chenevert C, King T.
Environmental contamination due to methicillin-resistant
Staphylococcus aureus: possible infection control implications. Infect Control Hosp Epidemiol. 1997;18(9):622-627.
4. French GL, Otter JA, Shannon KP, Adams NM, Watling D,
Parks MJ. Tackling contamination of the hospital environment by methicillin-resistant Staphylococcus aureus (MRSA):
a comparison between conventional terminal cleaning
and hydrogen peroxide vapour decontamination. J Hosp
Infect. 2004;57(1):31-37.
5. Wilson AP, Hayman S, Folan P, et al. Computer keyboards
and the spread of MRSA. J Hosp Infect. 2006;62(3):390-392.
6. National MRSA education initiative: preventing
MRSA skin infections. Centers for Disease Control
and Prevention website. www.cdc.gov/mrsa/. Reviewed
September 8, 2008. Updated September 11, 2008.
Accessed May 24, 2010.
7. Kramer A, Schwebke I, Kampf G. How long do nosocomial
pathogens persist on inanimate surfaces? A systematic
review. BMC Infect Diseases. 2006;6:1186-1192.
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
...........................................................................................................
MY PERSPECTIVE
The Fate of Certificate Programs
Richard Bower, MEd,
R.T.(R), is radiography
program director at the
Hendrick Medical Center
School of Radiography in
Abilene, Texas.
“My Perspective” features guest
editorials on topics in the
radiologic sciences. Opinions
expressed by writers do not
necessarily reflect those of the
ASRT. Those interested in writing an editorial should e-mail
[email protected].
It is important to recognize that the
fate of certificate programs is in the
hands of a political process. Decisions
cannot be implemented or changed
by any other means. Many of those
who are embracing the move toward
a 2-year degree as a minimum educational requirement today will be complaining about change in the future
when their program is threatened.
There is reason to believe that the next
step in the process is to require a baccalaureate degree. By adding computed
tomography (CT) to the basic curriculum, the door is opened to the argument that there is simply not enough
time to include the entire curriculum
in an associate degree program.
Moving from certificate programs
to degree programs has been occurring naturally over time without
the need for a board decision. It is
insensitive for us not to consider that
some who have given their lives to
our profession are losing their jobs
because of a vote. This happened to
some program directors when the
master’s degree was required without
grandfathering. Proponents argued
that it “shouldn’t be an impossible burden.” Still, there were those who felt
betrayed by the profession for having
to make a decision to spend thousands
of dollars for a degree or retire.
The American Registry of Radiologic
Technologists (ARRT) requirement to
have a degree for eligibility is forcing
some programs to reduce the number
of hours that they can offer to students
in both didactic and clinical aspects
of the program. This is compounded
by the American Society of Radiologic
Technologists (ASRT) curriculum
requirement (vs recommendation) to
add nonprofessional general education
hours.1 General education hours are a
good idea but unless the total number
of program hours is increased, hours
for professional course work must be
reduced to accommodate the general
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
education courses. For example, an associate degree program may be limited
to 72 semester hours by the state coordinating board. I believe if a certificate
program has 72 hours, those hours must
be reduced to include the additional
general education hours if the program
transfers sponsorship to a college. A
certificate program can add these hours
without a reduction.
Adding CT skills to the professional
curriculum results in even less time
spent on the basics for an entry-level
radiographer. CT currently is covered
by an advanced examination. Unless the
long-range goal is to combine the CT
and radiography registries, it does not
seem expedient to require radiography
programs to teach the supporting curriculum for CT.
Is CT an advanced modality or not?
We should insist that CT certification
require additional formal training and
an advanced exam for evaluation. We
send a mixed message when we require
CT as an entry-level skill and as an
advanced exam.
The ARRT practice analysis is used
by the Registry to describe the job
responsibilities of those employed in
the profession. Clinical competency
requirements of the ARRT are based
on the task inventory, which requires
that an activity be performed by at least
40% of technologists to be included.2
If the task analysis indicates that 40%
of entry-level radiographers are performing CT prior to its inclusion in the
curriculum, does that not indicate that
additional postgraduate training was
required for those radiographers to
perform CT? In my opinion, to include
competency in CT within the 24-month
radiography program, hours must be
taken from teaching the basics.
We now are at the point at which the
majority cannot see any advantage to
certificate programs. Please consider that
these programs provide a service to the
students they graduate and the public
599
...........................................................................................................
MY PERSPECTIVE
they serve. Their advantages include:
Flexibility. Certificate programs have greater
flexibility in content inclusion and scheduling.
Standards are in place for the content of the
professional curriculum that must be followed to
maintain programmatic accreditation. When a
degree is required, hours spent in the professional
curriculum may have to be reduced to include topics such as state history. Another area of flexibility
is the fact that certificate program hours do not
have to adhere to a university schedule. Programspecific scheduling can accommodate unique
opportunities with advantages for students.
Access to infrastructure. In the hospital setting,
instructors often have immediate access to available infrastructure, including imaging equipment,
picture archiving and communication systems and
radiology information systems. Access to this technology by the university may require scheduling.
To furnish this equipment on campus is possible
but represents a tremendous expense.
Cost to the student. The cost to the student of a
radiologic science education can increase from
a few thousand dollars to tens of thousands of
dollars when that cost is moved from the hospital
certificate setting to the academic setting. The
more advanced the degree, the greater the cost
to the student.
Rural education initiative. The rural education
initiative involves training students in their local
community. In this model, training occurs closer
to home so that students do not have to leave jobs
and family while attending training. Certificate
programs often are ideal for meeting this employment need at reasonable cost. Sometimes communities without higher education opportunities
have medical facilities that are up-to-date and
progressive. These facilities can effectively train
radiographers who are more likely to stay in the
community and meet local staffing needs. Once
local positions are filled, graduates move to find
work elsewhere.
Emphasis on application of learning. In my opinion, the profession is becoming more academic.
That said, certificate programs traditionally have
emphasized application over scholarly study.
Some would argue that this is a problem. On the
other hand, do you want a surgeon to operate on
you who is a scholar or one who is good with his
hands? Balance is what’s needed. One aspect does
600
not have to exclude the other and it is not going to
hurt the profession to allow students a choice.
Less bureaucracy. College programs must deal with
the college administrative structure, state and federal regulatory agencies and hospital clinical site
administrations. Certificate programs work within
a single administrative structure, which reduces
the number of bureaucracies with which they deal.
To me, this allows the program director to spend
more time with students and less on bureaucratic
duties. A disconnect can occur between our training and the real world if educators are too far
removed from the clinical environment.
There are advantages and disadvantages to all types
of programs. Some battles can’t be won; you can only
swim against the tide for so long. Such is the plight
of certificate programs. For years they have often
required more training hours than their associate
degree counterparts. Registry exam pass rates have
been indistinguishable between the types of programs.
ARRT has found some evidence that graduates from
programs with programmatic accreditation have higher
scores. Programmatic accreditation is required of all
certificate programs, but is not required of regionally
accredited colleges and universities.3 Certificate programs that require the associate degree prerequisite
will require students to complete the equivalent of baccalaureate hours without the ability to grant a degree.
Often, there is still a waiting list to get into certificate
programs even when there is local competition for students with a college or university.
Now is the time for certificate programs to lead the
way to the next step in our profession’s advancement.
All certificate programs should skip the associate
degree stepping stone and become baccalaureate programs. Instead of trying to justify the existence of certificate programs, we need universities to provide the
affiliation necessary to take full advantage of the benefits that certificate programs have to offer. Universities
often are reluctant to offer credit for certificate programs until after the registry exam has been passed.
This will no longer be acceptable. Distance learning
opportunities are beginning to fill this need but they
need to be expanded. University programs with the
vision to make these affiliations will expand their student base and tap into a population demographic that
is presently unreachable.
Such a proposal will meet with much disapproval;
however, I believe the next logical step in the political
process will be the baccalaureate degree requirement.
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
...........................................................................................................
To think otherwise is short sighted. Those making the
decisions say that it is not their intent to close programs,
but actions speak louder than words. If we were serious
about requiring a baccalaureate degree as a professional
standard it could be done in short order without closing
any types of programs. One approach to support the
baccalaureate degree as the professional level is to make
proficiency in 2 or more disciplines a requirement for
earning a bachelor’s degree. ARRT can simply create
combination exams.
Professional excellence is a reflection on individuals,
rather than the type of program they graduated from.
Those students who excel in our programs would excel
regardless of the type of program they graduated from.
There is something in our nature that causes us to feel
comfortable about others following in our footsteps.
Consequently, those who graduate from a particular
type of program naturally feel obligated to defend it
as best. We need leaders with real vision who can see
beyond their own prejudice and into the future.
The number of certificate programs has been declining. The Joint Review Committee on Education in
Radiologic Technology reported 202 hospital certificate
programs in 20004 and 176 in 2008.5 Even so, some consider it necessary to eliminate them to advance the profession. The fate of certificate programs now lies in the
hands of the colleges and universities. Will they accept
the challenge? Will they come up with a model that will
make use of the unique advantages that certificate programs have to offer, or will they simply assimilate? In any
case, resistance is futile. ◆
References
1. American Society of Radiologic Technologists. Radiography
Curriculum. www.asrt.org/media/pdf/foreducators
/ED07_Curr_RadFinalApproved032307.pdf. Published
2007. Accessed March 31, 2010.
2. American Registry of Radiologic Technologists. Practice
analysis. www.arrt.org/examinations/practiceanalysis
/practiceanalysis.htm. Accessed March 31, 2010.
3. American Registry of Radiologic Technologists.
Radiography Certification Handbook 2008. http://arrt
pdf2.s3.amazonaws.com/publications/2008-HandbookRAD.pdf. Accessed April 9, 2010.
4. Joint Review Committee on Education in Radiologic
Technology 2000 Annual Report. www.jrcert.org
/pdfs/2000AnnualReport.pdf. Accessed April 9, 2010.
5. Joint Review Committee on Education in Radiologic
Technology 2008 Annual Report. www.jrcert.org/pdfs
/2008_annual_report.pdf. Accessed April 9, 2010.
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
601
...........................................................................................................
TEACHING TECHNIQUES
Reporting Academic Misconduct
Tess Calhoun, MSRS,
R.T.(R), is a diagnostic radiographer at Mid
State Orthopaedics &
Sports Medicine Center in
Alexandria, Louisiana.
Ben D Wood, MSRS,
R.T.(R), is an assistant professor in the radiologic sciences
program at Northwestern State
University in Shreveport,
Louisiana.
“Teaching Techniques” discusses issues of concern to
educators. The primary focus of
the column is innovative and
interesting approaches to teaching. Comments and suggestions
should be sent to
[email protected].
602
Academic integrity is the foundation
of a scholarly community. The loss of
this integrity threatens the reputation
of the educational institution and the
character of everyone involved.1-4 Some
researchers believe faculty and students
have a moral responsibility to monitor
academic misconduct.5 Perhaps it is difficult to monitor such behavior from the
student perspective because the definition is so varied.
Academic misconduct encompasses a
wide array of offenses, but the most comprehensive definition that can be gleaned
from the research states that academic
misconduct is an offense committed by
cheating in the form of copying or sharing test answers, lab reports or homework; using published material without
proper citations; paying for a paper;
impersonating another student in online
classrooms; using papers more than once
for 2 or more different classes; unauthorized collaboration with classmates;
and finally, witnessing any of the above
behaviors and failing to report the misconduct to the appropriate authority.1,2,6,7
According to several studies, dishonest
behavior is on the rise in institutions of
higher education.1,7-9
A study conducted by Rennie and
Rudland found medical students became
desensitized to the occurrence of academic misconduct as they progressed
through the program, and they were
more accepting of various forms of cheating as normal behavior.7 One theory,
presented by Petress, is that faculty and
students do not take active roles in the
education process and campus culture,
and this results in an atmosphere of not
caring.2 Education is an active experience that requires trust and honesty.
It is an “investment” in the future. It is
more than just a diploma and includes
“inherent values, long term dedication
and commitment, and invested effort
toward noble goals.”2 Allowing academic
misconduct by not taking responsibility
for it devalues the entire experience and
diminishes the worth of an education.
Upholding the integrity of educational
institutions requires a combined effort
between faculty and students.2
Method
Articles for this review were located
using the Academic Search Complete
database and Google Scholar search
engine. The search parameters of the
database were set for peer reviewed
articles published within the past 5 years.
Using the words “academic dishonesty”
yielded 74 results, “students and cheating” resulted in 134 articles and 51
results were returned when “students and
cheating” were combined with the word
“ethics.” Only articles pertaining to academic misconduct and its prevalence and
student and faculty responsibility were
used for this review.
Faculty Responsibility
Traditionally, academic misconduct
penalizes only the person who committed the dishonest act. This is usually the
student and never the faculty member.
However, an instructor who does not
monitor carefully or provides opportunity to cheat is as guilty as the student
in question.5,6,9 It is the responsibility
of university administration to provide
students with “a high quality education,
to develop moral and engaged citizens,
and to uphold the highest standards
of integrity.”6 Faculty members have a
responsibility to set the example. If they
display a nonchalant attitude toward
cheating, students can hardly be expected to take an active role in monitoring
academic misconduct.3,9
Faculty members sometimes overlook
academic indiscretions for various reasons. Most of the time it is because the
process of reporting and disciplining is
too time consuming and cumbersome.
They also may feel uncomfortable confronting the student.5,6,9 According to
Hughes and McCabe, some faculty members fail to follow established policies and
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
...........................................................................................................
report dishonest behavior.6 Instructors have an obligation to promote learning through an environment of
trust and prevent academic dishonesty as much as possible. Faculty must develop the moral character of their
students and hold them to a high standard. Anything
less would produce substandard, incompetent citizens
and could jeopardize students’ futures.2,9
Another responsibility of the instructor includes
reviewing the honor policies with students. This helps by
letting students know what is expected of them. McCabe
found that 47% of students he surveyed whose school
did not have an honor code reported witnessing academic misconduct.9 This is almost twice as many students as
schools that did have an honor code. While the codes
are useful in preventing misconduct and giving students
guidelines for what to do when they observe dishonest
behavior, it is not the code but the campus culture that
has the greatest effect on academic behavior.2,3,5,6,9
An environment must be created where dishonesty
is seen as unacceptable. Faculty members have a role
in influencing this.2,3,9 It is the instructor’s responsibility to follow university procedures when dealing with
dishonest behavior. It is important that the entire faculty handles student dishonesty uniformly. Otherwise,
some students may be reprimanded more than others or not at all.5 Following the policies consistently
ensures the process is fair. If students believe the
process is fair, they are more likely to follow the guidelines and become active in the process.3
Instructors who neglect to report incidents of misconduct are doing an injustice to honest students. Failure
to follow policies and report students may cause honest
students to resort to cheating to stay competitive. This
could cause otherwise honest students to feel pressured
to cheat to “level the playing field.”5,6,9 If instructors
do not take the matter seriously, there is no reason for
students to be concerned with the issue. By not taking
an active stance in discouraging dishonesty or by ignoring obvious infractions, faculty members are essentially
allowing misconduct.
Faculty members are responsible not only for preventing dishonest behavior, but also for educating students
about why it is wrong.6,9,10 McCabe suggested faculty
members who catch a student being dishonest use the
incident as a learning tool.9 Perhaps it would be an
opportune time to stress the importance of doing individual, honest work. It could be an opportunity for faculty to explain the purpose of the specific class.
Faculty members are responsible for helping students understand the ethical ramifications of academic
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
behavior. Turning a negative experience for one student into a learning experience for the whole class may
be beneficial in deterring future misconduct and gives
students a sense of responsibility for their education.
It is the instructor’s job to mold students who accept
responsibility for their actions. This requires instructors
to stop looking the other way and confront individuals
who engage in misconduct. Faculty members succeed
in their responsibility when students refrain from misconduct not out of fear of punishment, but because
they understand the value of integrity.9
Student Responsibility
Responsibility for monitoring academic misconduct
does not fall totally on faculty members. Students are
ultimately responsible for their own actions and using
moral judgment to ensure the integrity of their education. In an informal survey, however, Petress found that
80% of his students believed that monitoring their classmates was not their responsibility and that the instructor
should monitor students.2 Students do not believe it is
their business whether their peers cheat. There are several reasons why students feel this way.
Many students do not report their peers because they
fear retribution. They do not want to become the class
outcast or be criticized.3 They also excuse the behavior
as “not a big deal.” Staats et al explained a student’s
rationalization methods using the neutralization theory.4
They believed students minimized the seriousness of the
offense to dismiss it and not feel guilt. Students deny that
any harm is being done; therefore, they see no need to
get involved and escalate the situation.
Another reason students deny their responsibility to help monitor academic behavior is that they
believe everyone is cheating. If everyone is doing it
and instructors are not stopping it, then it must not be
that serious.4 Hughes and McCabe found that students
who believed academic misconduct was prevalent on
campus were more accepting of the behavior and more
likely to participate in it.6
Students have become more accepting of dishonest
behaviors because of the increasing pressures to succeed. Their attitude is that it is OK to do whatever it
takes to finish the class and move to the next one. This
can be seen in Rennie and Rudland’s study, in which
medical students became more accepting of various
dishonest behaviors as their work load increased and as
graduation approached.7
In larger classes, where the instructor may be overwhelmed, it is necessary for students to monitor and
603
...........................................................................................................
TEACHING TECHNIQUES
report peers who cheat. This also crosses over into
the online classroom. With the increase in technology
and use of online classes, it is even more important for
students to monitor their peers.3 It is not practical to
assume instructors can efficiently monitor their online
classes for academic dishonesty. In this case, it is more
likely that students will be aware of dishonest behavior
before the instructor. Students must report incidents
such as receiving a copy of the test through e-mail or
knowledge of groups of students completing assignments together.
Reporting peers who participate in academic dishonesty is not a vague responsibility. Some honor codes
require students to report suspected academic misconduct. Failure to do so is “passive acceptance,” which
makes the witness guilty too.2,5 Some research has suggested that students accept their responsibility in monitoring their peers when they could face consequences
for not reporting.8
Research also has shown that students were more likely to adhere to honor policies when they were allowed to
participate in making the policy. Students need to feel a
connection to the university and an ownership in their
education. When students participate in developing
honor codes, there is a mutual agreement between faculty and students about upholding academic integrity.3,6,8,9
Students who actively participate in upholding academic
integrity are more likely to report misconduct by their
peers when they believe that the problem is getting out
of control and threatening their education.3
Honor codes also help by clearly defining the responsibilities of the honest student. Firmin et al conducted an
experiment in which several students were questioned
about their reaction to witnessing a classmate cheat on
an exam.8 The authors found that many students were
confused about what they should do. Without clear
guidelines, many students were inclined to ignore the
incident. Having honor policies that outline what steps
should be taken when misconduct is observed helps students make the right decision and take responsibility for
monitoring peers.8
Ethical Considerations
Active and passive participation in academic misconduct has severe consequences for all involved.
These consequences go far beyond failing the class or
being expelled from the institution. The integrity of
the academic institution is threatened when students
and faculty choose to accept academic misconduct as a
normal occurrence that cannot be stopped. Dishonest
604
students rarely learn everything they are supposed
to, which can have a detrimental impact on everyone
around them.1,2,5,6,9 One area of concern addressed
by the literature is what happens when the unethical
behavior exhibited by academic dishonesty carries
over to the work environment.1,7 Many students choose
not to monitor peer behavior because they rationalize
that the other student is only hurting himself or herself. However, the consequences do not stop with the
dishonest student. Harding et al stated, “the behaviors
that result in low academic integrity could well extend
into professional practice — resulting in significant
consequences for the individual, the employer, its customers, and society in general.”1
Dishonest students are awarded credit based on the
instructor’s assumption that the work is original and an
accurate reflection of their knowledge, skills and abilities. Degrees are awarded on the same basis. This gives
future employers an incorrect idea of what the student
is capable of doing.1 Depending on the students’ field,
their performance and the people depending on them
could suffer as a result of their academic misconduct.1,9
When students enter the work force, they are expected
to be competent and to have learned the basics to perform the job correctly and efficiently. This is especially
true in the medical field.
The health care professions depend on the integrity
and honesty of practitioners.7 Students who continue
to practice unethical behavior in their health care
careers could put the lives of their patients at risk. This
is true for medical research as well. Medicine cannot
thrive unless research is valid and trustworthy. Rennie
and Rudland demonstrated with their survey the wide
acceptance of unethical behavior by fifth-year medical
students.7 Research by Simon et al presented the same
results regarding advanced students’ lack of ethical
concern with academic dishonesty.3 They suggested that
integrity should be consistently reinforced throughout a
student’s education.
Conclusion
Without integrity and trust, the value of an education is greatly decreased and the reputation of the
institution is tarnished. Monitoring academic behavior
is an important component of upholding integrity
within the academic community, but whose responsibility is it? The literature concludes that faculty and
students must both acknowledge their roles in monitoring academic dishonesty. The burden cannot fall
completely on one or the other. Faculty members may
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
...........................................................................................................
have the greater responsibility, but it is still an active,
collaborative effort.
If students do not understand the effect their silence
has on their academic and professional careers they will
continue to think that what their peers do is none of
their business. It is the instructor’s responsibility to help
students understand that it is not the punishment, but
the loss of integrity and reputation that should drive
them to do the right thing in reporting academic misconduct. ◆
References
1. Harding T, Carpenter D, Finelli C, Passow H. Does
academic dishonesty relate to unethical behavior in professional practice? An exploratory study. Sci Eng Ethics.
2004;10(2):311-324.
2. Petress K. What is a scholarly community and what are
our individual and collective responsibilities? Education.
2008;128(4):686-690.
3. Simon C, Carr J, McCullough S, et al. Gender, student perceptions, institutional commitments and academic dishonesty: who reports in academic dishonesty cases? Assessment
and Evaluation in Higher Education. 2004;20:75-90.
4. Staats S, Hupp J, Hagley A. Honesty and heroes: a positive psychology view of heroism and academic honesty. J
Psychol. 2008;142(4):357-372.
5. Parameswaran A. Student dishonesty and faculty responsibility. Teaching in Higher Education. 2007;12(2):263-274.
6. Hughes J, McCabe D. Understanding academic misconduct. The Canadian Journal of Higher Education.
2006;36(1):49-63.
7. Rennie S, Rudland J. Differences in medical students’
attitudes to academic misconduct and reported behaviour
across the years — a questionnaire study. J Med Ethics.
2003;29(2):97-102.
8. Firmin M, Burger A, Blosser M. Cognitive responses
of students who witness classroom cheating. Journal of
Instructional Psychology. 2007;34(2):110-116.
9. McCabe D. It takes a village: academic dishonesty. Liberal
Education. 2005;9:26-31.
10. Christe B. Designing online courses to discourage
dishonesty. Educause Quarterly. 2003;4:54-58.
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
605
...........................................................................................................
ON THE JOB
A Review of Thermal MR Injuries
Paul T Hardy II, BS, is
a medical device reviewer
for the U.S. Food and Drug
Administration (FDA) Center
for Devices and Radiologic
Health (CDRH), Office of
Surveillance and Biometrics,
Division of Postmarket
Surveillance, in Silver Spring,
Maryland.
Kathleen M Weil, BS, RN,
is a medical device reviewer for
the U.S. FDA CDRH, Office of
Surveillance and Biometrics,
Division of Postmarket
Surveillance, in Silver Spring,
Maryland.
Since its introduction into the clinical arena in the mid-1980s, magnetic
resonance (MR) imaging has become
an important diagnostic tool, not only
because it is noninvasive and relatively
safe, but also because it has shown
increasing clinical applicability. The
technology for MR imaging procedures
has evolved considerably, resulting in
systems with stronger static magnetic
fields, faster switching of gradient magnetic fields and higher radiofrequency
(RF) power.
Although MR imaging has proven to
be a safe and effective modality when
properly used, clinicians and regulators have become increasingly aware of
the risks associated with this device, as
well as the physical phenomena responsible for these risks. The number of
MR imaging-related adverse events has
increased steadily since the first years
of clinical use (see Figure 1), which
may be due to the increase in the number of MR procedures.1 Skin injuries
are the primary type of adverse events
reported to the U.S. Food and Drug
Administration (FDA). It is part of the
FDA’s mission to convey the risks of
MR imaging by providing guidance
Figure 1. Thermal injuries by year. Source: the U.S. Food and Drug
Administration’s Manufacturer and User Facility Device Experience database.
606
documents for safer use of MR and
releasing public health notifications
describing specific risks and actions for
avoiding or reducing risks.2,3
Health care and independent scientific organizations, such as The Joint
Commission and the ECRI Institute,
also have cited a heightened awareness
of skin injuries related to MR imaging
use and have called for greater caution during scanning. On February
15, 2008, The Joint Commission
highlighted increasing patient safety
issues with MR imaging by releasing a
Sentinel Event Alert. This alert urged
hospitals and ambulatory care centers
to “pay special attention to preventing accidents and injuries during MRI
procedures.”4 The ECRI Institute cited
MR imaging-related thermal injuries
among its 2010 top 10 list of technology
hazards. According to ECRI, these hazards are among the top safety issues in
health care overall. 5
Most of the adverse events that
occur in practice are not due to system
malfunctions, but to improper patient
management (eg, positioning or considerations related to body size, weight
and medical history) or improper use
of the equipment before or during the
imaging procedure. All members of the
clinical team play an important role in
preventing these adverse events.
This article presents a 12-year
retrospective review of thermal injuries reported to the FDA’s Center
for Devices and Radiologic Health
(CDRH) through its MedWatch program, including a summary of possible mechanisms responsible for MR
imaging-related skin injuries. Although
symptoms of most thermal-related injuries are not immediately noticeable by
either the patient or clinician during
or after the MR imaging, steps can be
taken during the procedure to prevent
them. This review also provides a list of
guidelines to help clinicians minimize
MR imaging-related adverse events.
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
...........................................................................................................
Mechanisms of Thermal
MR Injury
In general, safety concerns related to MR-imaging
systems arise from its high-power RF pulses that are
emitted by the body coil and magnetic gradient field
pulses. The RF pulses can induce currents in specific
situations that are believed to be the origin of thermal injuries.
Interactions with metallic implants, pacemakers
and external devices, such as pulse oximetry leads
and electrocardiogram (ECG) cables, have been
associated with MR imaging-related thermal injuries
(see Box). However, even in the absence of metallic
implants, the body can act as a conductor of current that may induce heating when parts of the body
come into contact with each other and form a closed
loop. For example, a patient lying supine with clasped
hands, or a thumb touching the side of his or her leg
during a scan, can form a closed loop that acts as a
pathway for induced currents.
Box
In October 2009, a 20-year-old man underwent a head
and cervical spine magnetic resonance (MR) imaging
scan following a car accident. During this scan, the
patient was connected to a pulse oximeter for continuous monitoring. Immediately following the scan,
he complained of burns on his hand where the pulse
oximeter’s finger grip was attached. Upon examination, the patient was diagnosed with second- and
third-degrees burns on his hand and fingers and had to
undergo surgery for skin grafting to the burned areas.
location of injury was determined by the first body part
mentioned as incurring a thermal injury. General anatomical terms were used to group similar reports (eg,
torso, leg and feet). The reported cause of injury also
was captured using simple terms such as “bore contact,”
“coil contact,” “RF” and “burn” when it was available in
the report narrative.
Review of Reported Adverse Events
Founded in 1993, MedWatch is the FDA’s reporting system for adverse events. An adverse event is
any undesirable experience associated with the use
of a medical product. 6 The MedWatch system collects adverse event reports primarily related to drugs
and medical devices. Hospitals, consumers and
patients can voluntarily report adverse events using
FDA’s 3500 form; manufacturers are required to
report adverse events using FDA form 3500A. These
reports are submitted to a database known as the
Manufacturer and User Facility Device Experience
Database System (MAUDE) and are subsequently
reviewed by FDA analysts.7
Methods
We searched MAUDE data for reports received
between January 1, 1997, and December 10, 2009, using
MR imaging manufacturers’ names and the FDA product codes for MR imaging systems. A keyword search was
then used to locate events specific to thermal injuries.
Keywords used included “burns,” “blisters,” “pain,” “redness” and “erythema.” The final subset of reports was
exported to a spreadsheet for closer review. Reports not
associated with thermal injuries obtained during MR
imaging procedures were excluded.
The reports were then categorized by the primary
location of the injury, the secondary location of the
injury and the reported cause of the injury. The primary
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
Results
The results of the MAUDE search produced 760
reports, which were narrowed to 468 reports after the
keyword search was performed. Of the 468 reports, 419
were related to thermal injuries and are the focus of
the following results.
Number of Thermal Injuries per Year
In spite of the increased awareness of thermal
injuries related to MR imaging and the increasing
numbers of studies and publications on the subject,
the number of adverse events reported to the FDA
grew steadily from 1997 to 2008. This increase may
be partly due to a rising number of MR imaging
procedures globally, as well as better reporting of
MR imaging adverse events. In 2009, the number
of thermal injuries reported actually decreased to
almost 2007 levels. We hope this is due to heightened
awareness of the causes of these injuries and not to
underreporting.
Primary Location of Injury
Most thermal injuries involved the extremities
(58%), including the arms, elbows and hands. This was
followed by areas on the torso (19%), including the
shoulder, back and hips (see Figure 2). Only 6% of the
adverse events reported did not identify the primary
location of the injury.
607
...........................................................................................................
ON THE JOB
Guidelines for Reducing
Thermal Injuries
608
Hip
Back
Feet
Butto
cks
Wris
t
Pelv
is
Ankl
e
Leg
Not r
epor
ted
Shou
lder
Head
Face
Knee
Arm
Elbo
w
Thig
h
Hand
Tors
o
Fore
arm
The following information for
clinical staff using MR equipment
was derived from a variety of guidelines and articles. This information
may help clinicians take precautions
to avoid adverse outcomes.
■ Provide formal training for
those who work near the
MR imaging control room
or equipment to ensure the
safety of patients from all MR
imaging-related injuries.8,9
■ Read the instruction manual
before operating MR imaging equipment and performing scans on patients.9
Manufacturers of the MR
Figure 2. Primary location of injury. Source: the U.S. Food and Drug Administration’s
Manufacturer and User Facility Device Experience database.
imaging systems, as well
as the coils, provide good
information about the inner
workings of their systems (eg, acceptable specific
Reported Cause of the Injury
absorption rates, timely servicing of equipment
The majority of thermal injury reports also identiand correct patient positioning).
fied the cause of the injury (72%) compared with
■ Regularly review and update facility policies and
reports in which the cause was not identified (28%)
procedures on the safe use of MR equipment.8
(see Figure 3). The top 4 reported causes of thermal
■ Before initiating a scan, ensure that the scanner
injuries included contact with either the MR bore
has been properly maintained and is in working
(25%) or coil (14%), followed by contact with a fororder, and the insulation, RF coils and other comeign object (14%) or skin-to-skin contact (11%).
ponents are intact and well maintained.9,10
■ Thoroughly question patients about their medical history, particularly implanted
devices. Documentation should
note the device type and date
implanted. 8 Most implanted
devices have undergone MR imaging safety testing. However, technologists also should follow their
facility’s policies and procedures
to ensure that patients can safely
undergo MR scanning.
■ Thoroughly examine the patient’s
skin prior to MR imaging for permanent cosmetics or decorative
tattoos and objects such as drug
delivery patches, superficial metallic
sutures, surgical scars and piercings.
Figure 3. Reported cause of injury. Source: the U.S. Food and Drug Administration’s
Examining surgical scars may help
Manufacturer and User Facility Device Experience database.
identify implanted devices.8,9
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
...........................................................................................................
■ Instruct patients to avoid crossing their arms,
legs, fingers or hands because these can form a
large conductive loop and lead to thermal injury. Be aware that skin folds, such as those in the
abdominal area and thighs, also may be prone
to thermal injury. 8
■ Provide thermal insulation (eg, padding or air)
to areas of the patient that are most likely to
experience skin injuries (eg, areas of skin-toskin or skin-to-machine contact). Use only the
manufacturer-recommended insulation material
at the recommended thickness. Place insulation
material between the patient’s skin and the local
RF coils and pad the RF coils. 8-10
■ Communicate with clinicians caring for the
patient and find out what electrical equipment can
be removed during the scanning.8
■ Only allow devices that are cleared for use
with MR imaging to be attached to the patient
during scanning, such as ECG cables and electrodes. If electrical equipment must remain
in place during the scan, make sure that the
electrical equipment contacts the patient’s skin
as little as possible and there aren’t any loops
in the device, such as those that can occur with
cables. If contact between the cables or leads
and the patient’s skin cannot be avoided, cold
compresses and ice packs have been recommended as a method for preventing thermal
injury. However, caution should be taken with
this method as well. 8,9
■ Continually monitor the patient during the
scan. If the patient experiences any sensations
of overheating, such as discomfort, tingling or
burning, stop the scan immediately. 8 Although
there may be no immediate sign of skin injury,
delayed signs have been reported to the FDA up
to 24 hours following the scan.
■ Patients who are sedated, anesthetized or unconscious are at even greater risk of injury and should
be examined carefully. Leads or cables should be
repositioned after each imaging sequence.8
■ If a skin injury occurs, follow the necessary
steps to submit a medical device report.8 There
are simple instructions on the FDA’s website.6
Provide as much information as possible in the
report, including the scan’s duration, types of
pulse sequences involved, the machine’s field
strength (eg, 1.5T or 3T) and the patient’s
distance from the bore and the coil. Accurate
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
tracking of adverse events is important because it
ultimately improves patient safety.
Conclusion
Most thermal injuries caused by MR imaging
occur in the extremities as a result of direct contact
with the machine’s components or from a closed
loop formed by equipment or parts of the body.
With increased awareness and ongoing education,
the number of thermal injuries can be dramatically
reduced. It is essential that MR technologists play a
prominent role in maintaining a safe and effective
MR imaging environment. ◆
References
1. Harris C. MRI procedure growth rate slows, study shows.
AuntMinnie.com. www.auntminnie.com/index.asp?Sec=s
up&Sub=mri&Pag=dis&ItemId=81355. Published June 5,
2008. Accessed May 27, 2010.
2. U.S. Food and Drug Administration. A primer on
medical device interactions with magnetic resonance
imaging systems. www.fda.gov/MedicalDevices
/DeviceRegulationandGuidance/GuidanceDocuments
/ucm107721.htm. Draft released for comment on February
7, 1997. Updated June 18, 2009. Accessed October 30, 2009.
3. U.S. Food and Drug Administration. MRI safety. www
.fda.gov/MedicalDevices/Safety/AlertsandNotices
/ucm135362.htm. Updated October 8, 2009. Accessed
October 30, 2009.
4. Sentinel Event Alert: The Joint Commission. Preventing
MRI Accident and Injuries. February 14, 2008.
5. ECRI: 2010 top 10 technology hazards. Health Devices.
2009;38(11):1-10.
6. U.S. Food and Drug Administration. What is a serious
adverse event? www.fda.gov/Safety/MedWatch
/HowToReport/ucm053087.htm. Updated June 25, 2009.
Accessed October 30, 2009.
7. U.S. Food and Drug Administration. How to report a
problem (medical devices). www.fda.gov/MedicalDevices
/Safety/ReportaProblem/default.htm. Updated June 18,
2009. Accessed October 30, 2009.
8. Kanal E, Barkovich AJ, Bell C, et al. ACR guidance document for safe MR practices: 2007. AJR Am J Roentgenol.
2007;188(6):1447-1474.
9. Shellock FG, Crues JV. MR procedures: biologic effects,
safety, and patient care. Radiology. 2004;232(3):635-652.
10. Dempsey MF, Condon B. Thermal injuries associated with
MRI. Clin Radiol. 2001;56(6):457-465.
609
...........................................................................................................
WRITING & RESEARCH
Choosing the Right Sample
Julie Gill, PhD, R.T.(R)
(QM), is secretary-treasurer
of the ASRT and a former
member of the Radiologic
Technology Editorial Review
Board. Dr Gill is chairperson of the Allied Health
Department and an associate
professor at the University of
Cincinnati Raymond Walters
College.
“Writing & Research” discusses issues of concern to writers
and researchers and is written
by members of the Editorial
Review Board. Comments and
suggestions should be sent to
[email protected].
The best research studies are carefully
planned. They have a clearly defined
problem and hypothesis, appropriate
research methods, reliable survey instrument and a sufficient sample size. The
sample is the portion of the surveyed
population that participates in or is
included in the study. The population is
everyone who has one or more characteristics in common that are of interest to
the researcher. The sample, or portion of
the population that the researcher selects
to study and analyze, must be large
enough to be statistically significant, but
not so large that the results carry no statistical importance. Choosing the sample
is a delicate balance.
What Factors Influence
Sample Size?
A common misconception is that
researchers should include as many subjects as they can afford. However, a large
sample size is not always the best policy
and is often unnecessary. The sample
size helps to determine data collection
techniques, can influence the way participants are recruited and may affect the
study’s costs.
The 3 primary questions related to
sample size are:
1. How accurate do you wish your
results to be?
2. How confident do you wish to be in
your results?
3. What is your budget for the study?1
Although the quick response might be
that all 3 should be as high as possible,
the problem is that these 3 questions
are interconnected. If accuracy or confidence (or both) increase, then a larger
sample size will be necessary and perhaps
a larger budget. Therefore, a compromise between accuracy and confidence
is usually best when determining sample
size. A 95% confidence level is most frequently used and accepted.1 This means
that 95 times out of 100, the survey
results would be within a certain range.
It means that the sample (a portion of
610
the population of interest) generally represents the population (those with characteristics of interest to the researcher)
within a certain margin of error.
Along with confidence level, confidence interval also must be considered.
The confidence interval is the range that
likely includes the true value. The confidence interval can be viewed as a margin
of error for a certain value. The wider
the confidence interval, the more likely
an error has been made in interpreting
the data, so more data are needed.2 With
a 95% confidence level and a ⫾5 confidence interval, if 67% of a sample chooses the same response, then a researcher
can be relatively certain that if the same
question were posed to the entire population, between 62% and 72% would
choose the same answer.
Approaches to Determining
Sample Size
If the population for a study is small,
the entire population could be used as
the sample. With extremely small populations (50 or fewer), nearly the entire
population would have to be sampled to
achieve accurate results.3
Another approach for determining
sample size is to use the same size as
was used in a similar study. It is helpful
to note the sample sizes used for similar research while conducting the literature review for the new study. In addition to helping determine appropriate
sample size, reading the procedures
and methods used for similar studies
helps researchers avoid repeating others’ errors.
The type of study also influences
sample size. Most research studies
involve a cross-section of the population.3 For instance, if the research’s
purpose is to study the extent to which
perceptions regarding personal health
influence the intended year of retirement for radiology administrators, the
ideal population and sample would
represent the continuum from excellent
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
...........................................................................................................
health to poor health and a range of possible retirement years. A sample size for this study might include
a large number of radiology administrators. However,
if the research aims to determine whether meditating
for 15 minutes immediately before work influences
the number of work years, then a smaller population
and sample size could be used. This longitudinal study
would necessitate prolonged contact with the sample
subjects to collect data over a period of time.4
There are also plenty of websites that will calculate
sample size at no cost. If the researcher knows the
desired confidence level and confidence interval and
the population size, the formula will indicate how large
the sample size should be. For example, the Creative
Research Systems5 site calculated that for a 95% confidence level, a confidence interval of 3 and a population
of 500, the sample size should be 341. This means that if
500 technologists are asked to complete an online survey, but only 300 complete the survey, they may have to
be asked again until the sample size reaches at least 341.
If the thought of mathematical formulas is keeping
you from conducting research on your profession, fear
not! There are many expert statisticians who can do the
work for you. Many colleges and universities have faculty
or graduate students who can help with statistical analysis and most teaching hospitals and clinical facilities also
employ at least one statistician who might be helpful.
The ASRT Editorial Review Board members also may
be able to point you in the direction of someone in your
area who can help you. ◆
References
1. DePoy E, Gitlin LN. Introduction to Research: Understanding
and Applying Multiple Strategies. 2nd ed. St. Louis, MO:
Elsevier; 2005.
2. Best JW, Kahn JV. Research in Education. 10th ed. Boston,
MA: Pearson Education; 2005.
3. Israel GD. Determining sample size. University of Florida
IFAS Extension website. https://edis.ifas.ufl.edu/pd006.
Accessed November 25, 2009.
4. Allison PD. Multiple Regression: a Primer. Thousand Oaks,
CA: Pine Forge Press, 1999.
5. Creative Research Systems. Sample size calculator website.
www.surveysystem.com/sscalc.htm. Accessed November
25, 2009.
......................................................................................... . . . . . . . . . . . . . . . . . . . . . . . . . .
PATIENT PAGE
Magnetic Resonance Safety
Unlike x-ray exams, which use ionizing radiation, magnetic resonance
(MR) images are created with magnetic
fields and radio waves. MR scanning is
a very safe and effective technique for
examining the body’s soft tissues, such as
organs, muscles, ligaments and tendons.
However, because MR scanning uses a
powerful magnet, patients need to know
about some special precautions and
check-in procedures.
No metal is allowed in the room
where MR scans are performed because
metal objects are attracted to the magnet. The magnet is always “on,” whether
or not scanning is going on. On rare
occasions, patients and health care
professionals have been injured
when an object suddenly was
drawn to the magnet. Also,
metal objects can create “artifacts” on MR scans, making it
difficult or impossible to see the
patient’s anatomy. For your own
safety and comfort, for the safety
of the staff who will care for you,
and to ensure a high-quality
diagnostic exam, please follow
these guidelines.
You will not be allowed to
wear a watch or any jewelry,
including body piercings, during
the exam. It may be best to leave
these items at home, although
some facilities provide a safe
This MR image of a spine shows
place to store your valuables
permanent metal hardware used to repair
during your exam. Barrettes,
damage (arrows).
hairpins, eyeglasses, dentures
and hearing aids also must be
removed. Some types of cosmetics contain small amounts of metal, so avoid
wearing any makeup the day of your
exam. Also avoid clothing with metal
zippers, rivets, buttons or metallic fabric.
For more information,
Empty your pockets of all metal items,
contact the American Society
including coins, money clips, credit
of Radiologic Technologists,
cards, pens, pocketknives, keys, safety
15000 Central Ave SE,
pins and paper clips. Permanent metal
Albuquerque, NM
dental work, such as crowns, fillings and
87123-3909,
nonremovable braces, do not normally
or visit us online at
cause a problem during MR scans.
www.asrt.org.
This patient education page
provides general information
concerning the radiologic sciences. The ASRT suggests that
you consult your physician for
specific information concerning your imaging exam and
medical condition. Health care
professionals may reproduce
these pages for noncommercial educational purposes.
Reproduction for other reasons
is subject to ASRT approval.
RADIOLOGIC TECHNOLOGY July/August 2010, Vol. 81/No. 6
Metal wheelchairs and oxygen tanks
are not permitted near the MR magnet. However, special MR-safe versions
may be available. If you have questions
about any medical equipment you use,
ask the MR technologist who will perform your exam. He or she is a skilled
professional educated in anatomy, positioning and the safe use of magnetic
resonance technology.
The technologist will screen you
before your exam. He or she will check
you for metal objects and ask you a series
of questions about metal that might be in
or on your body. Think carefully about
these questions, answer them truthfully
and ask the technologist if there is anything you don’t understand.
Be sure to tell the technologist if you
have any of the following:
■ A pacemaker or artificial valve in
your heart.
■ Metal pins, plates, rods, screws or
nails anywhere in your body.
■ Wire sutures or surgical staples.
■ An intrauterine device (IUD) or
diaphragm.
■ An insulin pump.
■ An aneurysm clip.
■ A joint replacement.
■ An ear implant.
■ A stent, filter or coil in any blood
vessel.
■ Any type of prosthesis, including a
penile implant or artificial eye.
■ Permanent (tattooed) makeup,
such as eyeliner or lip coloring.
It also is important to tell the technologist if you ever have suffered a gunshot
wound or any type of accident that may
have left metallic particles in your body.
Depending on the type of metal and
where it is located, you may not be able
to have an MR exam. A radiologist, a
physician trained in interpreting medical
images, will decide whether you should
have the exam.
By knowing these important precautions and cooperating fully with the MR
technologist, patients can help ensure
that they have a safe and useful exam. ◆
615
Español
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . En
................
PATIENT PAGE
Seguridad de la Resonancia Magnética
Esta página educacional del
paciente provée información
general en cuanto a la ciencia
radiológica. ASRT sugiere que
usted consulte con su doctor
para obtener información específica concerniente a su examen
de imagen y condiciones
medicas. Los profesionales del
cuidado de la salud pueden
reproducir estas páginas para
ser usadas sin recibir lucro
económico. La reproducción de
estos documentos para ser usadas para otros objetivos necesita
la autorización del ASRT.
Para más información,
contáctese con la
Sociedad Americana de
Tecnólogos Radiológicos,
15000 Central Ave SE,
Albuquerque, NM 871233909, o visítenos en la web
electrónica: www.asrt.org.
616
A diferencia de los exámenes de rayos
X, que utilizan radiación ionizante, las
imágenes de resonancia magnética (RM)
se crean con campos magnéticos y ondas
de radio. La exploración por RM es una
técnica muy segura y eficaz para examinar los tejidos blandos corporales, tales
como órganos, músculos, ligamentos y
tendones. Sin embargo, dado que la RM
utiliza un potente imán, es necesario que
los pacientes conozcan ciertas precauciones y procedimientos antes de realizar
la práctica.
No se permite ingresar elementos
metálicos en la sala donde se realizan
exploraciones de RM porque éstos son
atraídos por el imán. El imán siempre
está en posición “encendido”, esté o no
tomando imágenes. Los pacientes y profesionales resultaron lesionados cuando
un objeto fue atraído repentinamente
hacia el imán. Además, los objetos metálicos pueden crear “artefactos” en las
exploraciones de RM, lo que dificulta o
imposibilita ver la anatomía del paciente.
Para garantizar un examen diagnóstico
de alta calidad, siga estas instrucciones.
Durante el examen no se permite
usar relojes ni alhajas, ni siquiera piercings. Lo mejor es dejar estos elementos
en casa, si bien ciertos establecimientos
disponen de un lugar seguro donde
puede guardar los objetos de valor.
También hay que sacarse pasadores,
horquillas, anteojos, dentaduras y
audífonos. Algunos tipos de cosméticos
contienen pequeñas cantidades de
metal, por eso evite ponerse cualquier
clase de maquillaje el día del examen.
Además, trate de no usar prendas que
tengan cremalleras, remaches, botones
o telas metálicas. Vacíe sus bolsillos de
todos los elementos metálicos, como
ser monedas, sujetadores de dinero,
tarjetas de crédito, lapiceras, cortaplumas, llaves, sujetapapeles y pasadores
de seguridad. Las piezas dentales de
metal permanentes, tal como coronas,
empastes y aparatos de ortodoncia fijos
normalmente no causan problemas
durante la RM.
No se permiten sillas de rueda ni tubos
de oxígeno de metal cerca del imán de la
RM. Sin embargo, exista algún tipo de estos
elementos que sea seguro para usar en casos
de RM. Si tiene dudas sobre el equipo
médico que pueda utilizar, consulte
con el tecnólogo de RM que le hará el
examen.
El tecnólogo controlará que no tenga
objetos metálicos y le hará una serie de
preguntas sobre los metales que pueda
tener dentro o sobre el cuerpo. Piense cuidadosamente en estas preguntas, respóndalas con la verdad y pregunte al tecnólogo todo aquello que no comprenda.
Asegúrese de decirle al tecnólogo si
tiene alguno de los siguientes elementos:
■ Marcapasos o válvula cardiaca
artificial.
■ Alfileres, placas, varillas, tornillos o
clavos metálicos en cualquier parte
del cuerpo.
■ Suturas de alambre o grapas
quirúrgicas.
■ Dispositivo intrauterino (DIU) o
diafragma.
■ Bomba de insulina.
■ Clip para aneurisma.
■ Reemplazo de articulaciones.
■ Implante auditivo.
■ Stent, filtro o espiral en un vaso
sanguíneo.
■ Cualquier tipo de prótesis, incluso
implantes peneanos u ojos artificiales.
■ Maquillaje permanente (tatuajes),
tal como delineador de ojos o de
labios.
También es importante comentar
al tecnólogo si alguna vez sufrió heridas por armas de fuego o algún tipo
de accidente que pueda haber dejado
partículas metálicas en el cuerpo. De
acuerdo con el tipo de metal y el lugar
donde se encuentra, tal vez no sea
posible realizarle una tomografía computada. Será el radiólogo quien decida
si debe someterse o no al examen.
Si cooperan plenamente con el tecnólogo en RM, los pacientes pueden ayudar a
que su examen sea seguro y provechoso. ◆
July/August 2010, Vol. 81/No. 6 RADIOLOGIC TECHNOLOGY
www.asrt.org/store
Most Requested!
■
Digital Mammography:
An Update
■
Breast Specimen Imaging
■
Multiple Sclerosis
■
Improving Communication
For Better Patient Care
Just Added!
■
Marfan Syndrome
■
Contrast Studies
■
Inflammatory Bowel
Disease
Stay Tuned!
More Classics will be coming your way.
essential
education
©2008 ASRT. All rights reserved.
© Carestream Health, Inc. 2010.
CONVERT YOUR
MOBILE TO
ELESS DR
WIRELESS
INTRODUCING THE DRX-MOBILE RETROFIT KIT
POWERED BY THE WIRELESS DRX1 DETECTOR.
Experience all the benefits of digital radiography and more by adding a
DRX-Mobile Retrofit Kit to your existing mobile system. By incorporating the
wireless DRX-1 detector you get instant images, streamlined workflow and
improved productivity at an affordable cost. All this with a wireless detector.
The DRX-Mobile Retrofit Kit. SIMPLE. GENIUS.
www.carestreamhealth.com/DRXmobile2
1-877-865-6325, ext. 413