Purpose: To prospectively compare high-, mid-, and low-resolution off-the-shelf displays currently employed by commercial testing centers, in terms of visibility of lesion features needed to render a diagnostic decision when possible diagnoses are provided in a multiple-choice format during a maintenance of certification (MOC) examination.
Materials and methods: The Psychometrics Division of the American Board of Radiology (ABR) approved the studies (human subjects and HIPAA compliant). One study compared 1280 x 1024 displays with 1024 x 768 displays; the second, 1600 x 1200 with 1280 x 1024 displays. Images from nine subspecialties were used. In each study, observers viewed images twice-once on each display. Diagnoses were provided, and observers rated visibility of diagnostic features.
Results: Of 7977 data pairs analyzed in study 1, the 1024 and 1280 displays received the same ratings for 5726 data pairs (72% of the time), with the 1024 display receiving a higher rating for 679 data pairs (9% of the time) and the 1280 receiving a higher rating for 1572 data pairs (19% of the time) (P < .0001). When rating differences existed, all subspecialties except nuclear medicine had significantly more high-visibility ratings with the 1280 display. Of 1090 data pairs analyzed in study 2, the 1280 and 1600 displays received the same ratings for 689 data pairs (63% of the time), with the 1280 receiving a higher rating for 162 data pairs (15% of the time) and the 1600 receiving a higher rating for 239 data pairs (22% of the time) (P = .0001). When rating differences existed, only cardiopulmonary and musculoskeletal images had significantly more high-visibility ratings with the 1600 display.
Conclusion: For the ABR MOC examinations, 1280 x 1024 displays should be used, compared to 1024 x 768 displays; 1600 x 1200 displays may be necessary for some images. Good-quality images must be used on the examinations, so digital rather than digitized film images should be used to ensure high-quality images.
RSNA, 2009