Urinary calculi on computed radiography: Comparison of observer performance with hard-copy versus soft-copy images on different viewer systems

OBJECTIVE. The purpose of this study was to compare observer performance fo r detecting urinary calculi using abdominal computed radiography with hard- copy versus soft-copy images and with a high-resolution video monitor versu s a liquid-crystal-display (LCD) monitor MATERIALS AND METHODS. We compared observer performance for detecting urina ry calculi using three sets of radiographs-hard-copy images, soft-copy imag es displayed on a LCD monitor (1280 x 1024 bits), and soft-copy images disp layed on a high-resolution video monitor using receiver operating character istic curve analysis with a continuous rating scale. Computed radiography w as archived with a 2140 x 1760 pixel resolution and a 10-bit depth. The sel ected data set included 62 images: 27 images showing proven urinary calculi smaller than 6 mm and three in number, and 35 images containing no proven abnormalities. Eleven radiologists (three genitourinary radiologists and ei ght general radiologists) participated in the study. Interpretations of thr ee sets of randomly distributed radiographs were performed individually in three separate sessions at I-week intervals. RESULTS, No statistically significant differences were found in the area un der the receiver operating characteristic curve for detecting urinary calcu li or in the interpreting times between soft-copy and hard-copy images; the mean areas under the receiver operating characteristic curve of hard-copy images, soft-copy images displayed on an LCD monitor, and soft-copy images displayed on a high-resolution video monitor were 0.579, 0.610, and 0.732, respectively. However, soft-copy images showed relatively improved diagnost ic accuracy among less experienced radiologists (p < 0.05). CONCLUSION. For detecting urinary calculi, soft-copy images offered a diagn ostic accuracy similar to or slightly more accurate than that of hard-copy images obtained in a laser-printed film-based environment. The diagnostic p erformance with soft-copy images viewed on an LCD monitor was comparable to that of soft-copy images viewed on a high-resolution video monitor.