Influence of 8-bit vs. 11-bit digital displays on observer performance and visual search:: A multi-center evaluation

Medical-grade monochrome monitors typically display 8 bits of data. This study determined if 11-bit displays could improve observer performance and decrease use of window/level. 8- and 11-bit displays from three manufacturers were used at three sites. Six radiologists at each site viewed 100 DR chest images (half with a pulmonary nodule) on both displays. Decisions, confidence, nodule location, viewing time, and window/level use were recorded. There was no significant difference in ROC Az as a function of bit depth. The average Az with 8 bits was 0.8284 and with 11 bits was 0.8253. There was a significant difference in viewing time favoring the 11-bit displays. Window/ level use did not differ. Eye position was recorded on a subset of images at one site. Cumulative dwell times for each decision category were lower with the 11-bit than with the 8- bit display. When tested with t-tests for paired observations, the TP (t = 1.452, p = 0.1507), FN (t = 0.050, p = 0.9609), and FP (t = 0.042, p = 0.9676) were not statistically significant. The difference in the TN decisions was statistically significant (t = 1.926, p = 0.05). 8-bit displays will not impact negatively diagnostic accuracy, but using 11-bit displays may improve workflow efficiency.