Quantitative digital subtraction coronary angiography using videodensitometry. An in vivo analysis.

A videodensitometric method for measuring absolute cross-sectional area and diameter has been tested in living dogs with coronary artery stenoses created surgically by placement of small Silastic cuffs. Coronary arteriograms were performed using a circular tomographic unit to provide multiple views of each lesion, and measurements were made from logarithmically subtracted digital images. Dimensions of 13 stenoses of cross section 1 to 5 mm2 and adjacent reference segments (2 to 9 mm2) were determined by histologic sectioning of the segments after injection with a rapidly hardening plastic fixative under physiologic pressure. Two different methods were tested for calculating cross-sectional area. On 238 measurements, 102 of normal vessel segments and 135 of stenoses, both methods showed good correlation with histologic measurements, with slopes of 0.929 + (SD) 0.037 (r = 0.8563) and 0.948 + (SD) 0.037 (r = 0.8554). Multiple measurements of each segment produced values within 30% of the true absolute cross sectional area in most cases. The method shows promise as a means for quantitating absolute dimensions of vessels in clinical arteriography.