Monochrome versus color softcopy displays for teleradiology: observer performance and visual search efficiency

[Objective evaluation of visual fatigue for reading of radiographs displayed on medical-grade liquid-crystal displays]

The aim of this study was to evaluate visual fatigue objectively by measuring accommodation time and critical fusion frequency (CFF) before and after reading posteroanterior chest radiographs displayed on medical-grade liquid-crystal displays (LCDs) under different monitor conditions. A color LCD (500, 170 cd/m²) and a monochrome LCD (500 cd/m²) were used in this study. Six observers independently kept reading the radiographs for two hours to understand various lung nodules in the "Fatigue Session". Objective visual fatigue was measured by using the accommodation device and the CFF meter before and after the Fatigue Session. The ambient lighting of the laboratory was set at 35 lux. Both the accommodation time and the CFF between before and after the Fatigue Session indicated statistically significant differences (p<0.05). Our results on accommodation time and CFF before and after reading the radiographs on medical-grade LCDs indicated that visual fatigue could be evaluated objectively.

Medical grade vs off-the-shelf color displays: influence on observer performance and visual search

The goal of this study was to compare diagnostic accuracy of radiologists viewing clinical images on a top-of-the-line medical-grade vs a top-of-the-line commercial off-the-shelf (COTS) color display with the luminance values set to simulate a display that had been in use for 1 year. A set of 50 digital radiography chest images was selected for use in the study, half containing a solitary pulmonary nodule and half nodule-free. The images were displayed twice to each of six observers, once on each display. Eye position was recorded on a subset of the images. Overall, there was a statistically significant difference (F = 4.1496, p = 0.0471) between the medical-grade color display and the COTS color display in terms of receiver operating characteristic area under the curve values, with the medical-grade display yielding higher diagnostic accuracy. Total viewing time did not differ significantly, but eye position data revealed differences, suggesting better search and decision-making efficiency with the medical-grade display. Medical-grade color displays at 1 year old yield better diagnostic and search efficiency than COTS color displays and thus are recommended for primary reading if color displays are to be used.