Characterization of plaque components with intracoronary ultrasound imaging: an in vitro quantitative study with videodensitometry.
We investigated whether videodensitometry provides a possibility of objective plaque characterization by intracoronary ultrasound imaging. Histologically matched 30 MHz ultrasound images of characteristic atherosclerotic lesions in saline solution and blood-perfused human coronary arteries in vitro were digitized, and regions of interest were analyzed by calibrated videodensitometry. Pixel gray-level distributions were represented as frequency histograms, and mean pixel gray level, skewness, and kurtosis were calculated. Similarly, images of flowing blood in vitro (n = 9; hematocrit 40%) were analyzed. Mean pixel gray levels differed between the three lesion types (lipid rich [n = 6], 71 to 92 [mean 80]; fibromuscular plaque [n = 14], 94 to 162 [mean 124]; and calcified plaques [n = 8]; 161 to 196 [mean 178]) (all comparisons p < 0.001). Ranges of mean pixel gray levels for flowing blood in vitro were within the range of those for fibromuscular plaque (86 to 103; mean 98). During blood perfusion in nine specimens, pixel gray levels were 85% +/- 7% of those during saline perfusion but with similar differences between plaque types. We conclude that homogeneous plaque types can be distinguished in vitro by videodensitometry on intracoronary ultrasound images.
Department of Cardiology, Academic Medical Center, Amsterdam, The Netherlands.
R J
RJ
Peters
W E
WE
Kok
H
H
Bot
C A
CA
Visser
D000368:Aged; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D003720:Densitometry / Q000379:methods; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D066298:In Vitro Techniques; D008297:Male; D018084:Ultrasonography, Interventional / Q000379:methods*; D014743:Videotape Recording