Hard-copy versus soft-copy image reading for detection of ureteral stones on abdominal radiography

The purpose of this study was to compare the usefulness of soft-copy images displayed on a cathode ray tube (CRT) with hard-copy images (film images) for detecting ureteral stones on abdominal radiography.

Five radiologists read images from 50 cases of ureteral stones and 50 normal cases diagnosed on the basis of intravenous urography and CT. For hard-copy reading, 10-bit images at 3,520x4,280 pixels obtained by computed radiography were printed on 14x17-inch films. For soft-copy reading, 8-bit images were displayed on a 17-inch monochrome monitor at 1,024x1,280 pixels. The study items were area under receiver operating characteristics (ROC) curve (Az), ureteral stone detection sensitivity and specificity, and reading time.

For soft-copy and hard-copy images, the average Az values were 0.855 and 0.851, sensitivity was 62.8% and 62%, and specificity was 70.8% and 62.4%, respectively. There were no statistically significant differences between these values. Reading time was 106.6 min for soft-copy images, significantly longer than the 71.2 min for hard-copy images (p<0.05).

Although soft-copy image reading time was longer than hard-copy image reading time, the ability to diagnose ureteral stones on abdominal radiography did not differ for soft- and hard-copy images.