Selective coronary angiograms were obtained using a real-time high-pass temporal filtration digital subtraction technique with videotape storage and display and compared to simultaneously recorded 35-mm cineangiograms for 32 stenotic lesions in 15 patients. Both methods were evaluated by three independent observers using caliper measurement of percent diameter reduction for each lesion. There was a good correlation between the two imaging methods for individual observers, though considerable variability was seen, r = .73, standard error of estimate (SEE) = 9.1%.
The average severity of stenosis and the interobserver variability were similar between methods. This digital subtraction technique for selective coronary angiography compares favorably with a conventional film-based technique for evaluation of coronary stenoses and offers advantages of real-time image processing, limited tolerance to patient motion, and relatively small digital memory requirements. In addition to further improvements in image quality, more objective computer-aided scoring methods are needed to reduce the variability in lesion analysis.