Comparison of the Commercial Color LCD and the Medical Monochrome LCD Using Randomized Object Test Patterns

Workstations and electronic display devices in a picture archiving and communication system (PACS) provide a convenient and efficient platform for medical diagnosis. The performance of display devices has to be verified to ensure that image quality is not degraded. In this study, we designed a set of randomized object test patterns (ROTPs) consisting of randomly located spheres with various image characteristics to evaluate the performance of a 2.5 mega-pixel (MP) commercial color LCD and a 3 MP diagnostic monochrome LCD in several aspects, including the contrast, resolution, point spread effect, and noise. The ROTPs were then merged into 120 abdominal CT images. Five radiologists were invited to review the CT images, and receiver operating characteristic (ROC) analysis was carried out using a five-point rating scale. In the high background patterns of ROTPs, the sensitivity performance was comparable between both monitors in terms of contrast and resolution, whereas, in the low background patterns, the performance of the commercial color LCD was significantly poorer than that of the diagnostic monochrome LCD in all aspects. The average area under the ROC curve (AUC) for reviewing abdominal CT images was 0.717±0.0200 and 0.740±0.0195 for the color monitor and the diagnostic monitor, respectively. The observation time (OT) was 145±27.6 min and 127±19.3 min, respectively. No significant differences appeared in AUC (p = 0.265) and OT (p = 0.07). The overall results indicate that ROTPs can be implemented as a quality control tool to evaluate the intrinsic characteristics of display devices. Although there is still a gap in technology between different types of LCDs, commercial color LCDs could replace diagnostic monochrome LCDs as a platform for reviewing abdominal CT images after monitor calibration

Track D Social Science, Human Rights and Political Science

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138414/1/jia218442.pd

The ROC curves of five individual reviewers for (a) the medical monochrome LCD and (b) the commercial color LCD.

<p>(c) The average AUC was 0.717 and 0.740 for the color and monochrome LCDs, respectively. No statistical significance can be found (<i>p</i> = 0.265).</p

Physical specifications of the diagnostic monochrome LCD and the commercial color LCD.

*<p>Displayed in the portrait shaped mode throughout this study.</p

The noise-sensitivity relationship for different LCDs.

<p>(a) Salt noise was added to the low background pattern, and (b) pepper noise was added in the high background pattern.</p

The average sensitivity curves for the point spread test under (a) the low background and (b) the high background conditions.

<p>As the <i>σ</i> increased, the curve slope of the commercial color LCD dropped more dramatically than the medical monochrome LCD.</p

Parametric combinations showing significant differences between the monochrome and color LCDs using Chi-square analysis.

<p>Parametric combinations showing significant differences between the monochrome and color LCDs using Chi-square analysis.</p

Examples of various ROTPs.

<p>The image patterns showed in the display devices for (a) the contrast test in the low background condition, (b) the resolution test in the high background condition, (c) the point spread test in the low background with <i>σ</i> of 5, and (d) the noise test with noise density of 0.1 in the high background.</p

The average contrast-sensitivity curves for different LCDs.

<p>(a) Under the low background, the grayscale at the threshold of 80% sensitivity was 188 and 113 for the color and monochrome LCDs, respectively. (b) Under the high background, the sensitivities for both monitors reached 100% when the grayscale difference between the background and the sphere exceeded 150. In <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0037769#pone-0037769-g003" target="_blank">Figs. 3</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0037769#pone-0037769-g004" target="_blank"></a><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0037769#pone-0037769-g005" target="_blank"></a><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0037769#pone-0037769-g006" target="_blank">6</a>, error bars show standard error, n = [100].</p

The average resolution-sensitivity curves for different LCDs.

<p>(a) Under the low background, the diameter corresponding to 80% sensitivity was 1.485 mm and 0.725 mm for the color and monochrome LCDs, respectively. (b) Under the high background, when the diameter exceeded 1 mm, no errors can be found with both monitors.</p