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Lowe J.M.,University College Dublin | Brennan P.C.,University of Sydney | Evanoff M.G.,American Board of Radiology | McEntee M.F.,University College Dublin
American Journal of Roentgenology | Year: 2010

OBJECTIVE. Quality assurance in medical imaging is directly beneficial to image quality. Diagnostic images are frequently displayed on secondary-class displays that have minimal or no regular quality assurance programs, and treatment decisions are being made from these display types. The purpose of this study is to identify the impact of calibration on physical and psychophysical performance of liquid crystal displays (LCDs) and the extent of potential variance across various types of LCDs. MATERIALS AND METHODS. Three display types were evaluated from Hewlett Packard, Viewsonic, and NEC, which totalled 36 LCDs. These displays were calibrated to the DICOM gray scale standard display function using a VeriLum photometer and associated software under the same ambient room conditions. The American Association of Physicists in Medicine Task Group 18 test patterns were used to measure minimum and maximum luminance, contrast ratios, luminance response, veiling glare (physical and psychophysical), psychophysical noise, spatial resolution, and display uniformity. RESULTS. Improvements after calibration were noted in all display types for luminance response and psychophysical evaluations of veiling glare. Minimum luminance, contrast ratios, and display uniformity improvements were noted in two separate display types. The only significant reduction in performance was noted for physical evaluations of veiling glare. CONCLUSION. The data presented show that calibration has a significant impact on the brightness and contrast of displays, and other display parameters are influenced by this. The amount of variation in performance that was still evident after calibration is of concern. © American Roentgen Ray Society.

Hendee W.R.,Medical College of Wisconsin | Becker G.J.,American Board of Radiology | Borgstede J.P.,University of Colorado at Denver | Bosma J.,American Board of Radiology Foundation | And 4 more authors.
Radiology | Year: 2010

The growth in medical imaging over the past 2 decades has yielded unarguable benefits to patients in terms of longer lives of higher quality. This growth reflects new technologies and applications, including high-tech services such as multisection computed tomography (CT), magnetic resonance (MR) imaging, and positron emission tomography (PET). Some part of the growth, however, can be attributed to the overutilization of imaging services. This report examines the causes of the over-utilization of imaging and identifies ways of addressing the causes so that overutilization can be reduced. In August 2009, the American Board of Radiology Foundation hosted a 2-day summit to discuss the causes and effects of the overutilization of imaging. More than 60 organizations were represented at the meeting, including health care accreditation and certification entities, foundations, government agencies, hospital and health systems, insurers, medical societies, health care quality consortia, and standards and regulatory agencies. Key forces influencing overutilization were identified. These include the payment mechanisms and financial incentives in the U.S. health care system; the practice behavior of referring physicians; self-referral, including referral for additional radiologic examinations; defensive medicine; missed educational opportunities when inappropriate procedures are requested; patient expectations; and duplicate imaging studies. Summit participants suggested several areas for improvement to reduce overutilization, including a national collaborative effort to develop evidence-based appropriateness criteria for imaging; greater use of practice guidelines in requesting and conducting imaging studies; decision support at point of care; education of referring physicians, patients, and the public; accreditation of imaging facilities; management of self-referral and defensive medicine; and payment reform. © RSNA, 2010.

Reed W.M.,University of Sydney | Ryan J.T.,University of Sydney | McEntee M.F.,University College Dublin | Evanoff M.G.,American Board of Radiology | Brennan P.C.,University of Sydney
Radiology | Year: 2011

Purpose: To measure the effect of abnormality-prevalence expectation on experienced radiologists' performance during pulmonary nodular lesion detection on a chest radiograph. Materials and Methods: A multiobserver receiver operating characteristic (ROC) and eye-position analysis study was performed to assess the effect of prevalence expectation on observer performance. Twenty-two experienced radiologists were divided into three groups and each was asked to interpret 30 (15 abnormal) identical posteroanterior chest images twice and decide if pulmonary lesions were present. Before each viewing, the radiologists were told that the images contained a specific number of abnormal images:group 1: 9 and 15; group 2: 15 and 22; and group 3: 15 and not told. Results:ROC analysis demonstrated that no significant effect could be measured as a function of prevalence expectation (P > .05). However, eye-position analysis showed significant increases in eye movements at higher prevalence expectation rates in terms of the number of fixations per image (group 1: P = .0001; group 2: P = .0001; group 3: P = .001) and the total scrutiny time of each image (group 1: P = .0001; group 2: P = .0283; group 3: P = .028). Conclusion: Overall, findings of this study showed no evidence that the accuracy of expert radiologists is altered due to changing prevalence expectation rates. However, the time spent interpreting each image and the number of fixations increased at higher prevalence rates. Maintenance of diagnostic efficacy has been shown even when circumstances challenge normal observer behavior. © RSNA, 2011.

McEntee M.F.,University of Sydney | Nikolovski I.,Royal North Shore Hospital | Bourne R.,University of Sydney | Pietrzyk M.W.,University of Sydney | And 3 more authors.
Academic Radiology | Year: 2013

Rational and Objectives: To investigate the effect of the Joint Photographic Experts Group (JPEG2000) 30:1 and 60:1 lossy compression on the detection of cranial vault fractures when compared to JPEG2000 lossless compression. Materials and Methods: Fifty cranial computed tomography (CT) images were processed with three different level of JPEG2000 compression (lossless, 30:1 lossy, and 60:1 lossy) creating three sets of images. These were presented to five musculoskeletal specialists and five neuroradiologists. Each reader read at two of the three compression levels. Twenty-two cases contained a single fracture; the remaining 28 cases contained no fractures. Observers were asked to identify the presence or absence of a fracture, to locate its site, and rate their degree of confidence. Receiver operating characteristic (ROC), jackknife free-response receiver operating characteristic (JAFROC) and the Dorfman-Berbaum-Metz multiple reader multiple case (DBM-MRMC) analyses were used to explore differences between the lossless and lossy compressed images. Results: JPEG2000 lossless and 30:1 lossy compression demonstrated no significant difference in their performance with JAFROC and DBM-MRMC analysis (P < .416); however, JPEG2000 30:1 lossy compression demonstrated significantly better performance than 60:1 lossy compression (P < .016). A significant increase in misplaced confidence ratings was also seen with 60:1 (P < .037) over 30:1 lossy and lossless compression. Conclusion: JPEG2000 60:1 compression degrades the detection of skull fractures significantly while increasing the confidence with which readers rate fractures compared with 30:1 lossy and lossless compression. JPEG2000 30:1 lossy compression does not significantly change performance when compared to JPEG2000 lossless for the detection of skull fractures on CT. © 2013 AUR.

Hirsch J.A.,Harvard University | Becker G.J.,American Board of Radiology | Derdeyn C.P.,University of Washington | Jayaraman M.V.,Brown University | And 2 more authors.
Journal of NeuroInterventional Surgery | Year: 2014

The ABNS, ABR, and ABPN have all embraced MOC as a core part of their ethos and practice. The vast majority of Society of NeuroInterventional Surgery members are certified by one of these three organizations. Depending on the year of primary certification, the parent board, and decisions regarding subspecialization such as the neuroradiology CAQs, many members are likely already participating in MOC programs. While some may argue with the desirability of the four core competencies of MOC generally, MOC nonetheless represents a new challenge for non-time limited certificate holders of the parent organizations. The future likely includes further expansion of MOC programs as hospitals, state licensure boards, and other organizations make participations in MOC a requirement of practice.

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