Practices and attitudes about cathode-ray tube-based and film-based image interpretation

Performance of film, desktop monitor and laptop displays in caries detection

OBJECTIVES

To compare film, desktop monitor and laptop displays of digitized film images for accuracy of caries detection.

METHODS

Sixty-four extracted teeth were mounted in eight models and radiographed with E-speed bitewing film. Films were digitized and displayed on a desktop monitor and a laptop display. Six observers scored the presence or absence of enamel and dentinal caries for each proximal surface for film, desktop and laptop displays. Results were compared with the histology of ground sections. ROC curve areas for each display mode and observer were assessed for significant differences with ANOVA.

RESULTS

Diagnostic accuracy for proximal surface caries detection was not significantly different for conventional film or desktop monitor and laptop displays for detection of enamel caries (P = 0.9112) or dentin caries (P = 0.2796).

CONCLUSIONS

Current laptop active matrix liquid crystal displays provide diagnostic quality for caries detection comparable with conventional film and desktop monitor displays.

Enhanced displays of medical images: evaluation of the effectiveness of color, motion, and contour for detecting and localizing liver lesions

RATIONALE AND OBJECTIVES

Many perceptual studies have shown that the detection of large, low-contrast targets is better either in color or in contrast-reversing presentations than in standard gray scale. We determined the value of several new display techniques for viewing liver computed tomography (CT) scans.

METHODS

Eight observers (four radiologists and four nonradiologists) viewed sets of 100 liver CT images (50 with lesions and 50 without) under five display conditions on a Macintosh computer: (1) color (equiluminant color contrast); (2) color-luminance (combined luminance and chromatic contrast); (3) flicker (luminance contrast that reversed polarity at 2 Hz); (4) contour (shaded intensity mapping); and (5) control (conventional gray scale). Receiver operating characteristics (ROC) techniques were used for analysis.

RESULTS

The measured ROC curve areas for the different viewing conditions were as follows: control = 0.77 +/- 0.01 (mean +/- standard error of the mean); color = 0.78 +/- 0.01; color-luminance = 0.82 +/- 0.01; flicker = 0.78 +/- 0.01; and contour = 0.76 +/- 0.01. The percentage of lesions correctly located ranged from 0.82 (color-luminance) to 0.75 (flicker). Performance under the color-luminance condition was significantly better than in the control condition (p = .01), whereas the other experimental conditions were not significantly different from the control condition (p > .21).

CONCLUSION

The use of mixed color and luminance displays may have perceptual advantages for radiologists and can improve performance over that of gray-scale viewing.