Radionuclide angiography in graded carotid stenosis. An experimental study with angiographic correlation.

Radionuclide and contrast angiographies were performed in 10 dogs. In 6 dogs unilateral or bilateral (partial or total) carotid occlusions were produced by silk ligatures. Follow-up angiographies were carried out at intervals up to 6 months following surgery. Visual assessment of the radionuclide carotid angiogram was compared to quantitative analysis of the time-activity curves over these areas. Several parameters of these curves were reviewed. The ratio of the slopes, was the most sensitive parameter of the assessment of carotid artery stenosis. The ratio of the slopes of the curves in normal dogs (mean 96 plus or minus 5.2 S.D.) was significantly different from that in animals with stenosis greater than 80% (mean 67.3 plus or minus 16.9 S.D.).