Abstract

Lossless compression achieves only modest data reduction in noisy medical image sequences such as digital coronary angiograms. Lossy compression achieves greater reductions, but diagnostic performance criteria for use of lossy compression in dynamically displayed image sequences have yet to be established. We performed a quantitative perception study to measure low contrast feature detectability within moving simulated arterial segments inserted frame by frame into actual human cardiac cine radiographs to produce dynamic displays with realistic quantum and structure noise. Thirty-frame angiograms were displayed in loop format at 15 fps. Three subjects made 200 observations of the original images and at each of three levels of JPEG compression in a four-alternative forced-choice experiment. Compressions of 6:1, 12:1, and 18:1 resulted in average relative detectability of 102%, 95%, and 64%, respectively, compared to the original images. Only the detectability loss at 18:1 reached statistical significance at the p<0.05 confidence level in this study. We conclude that observer performance techniques are able to quantify specific changes in actual diagnostic information. Our preliminary data suggest that detection of low contrast objects in coronary angiograms is not degraded for JPEG compression ratios of 12:1 or less.

© 1992 Optical Society of America