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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. 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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. 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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