Angiography is presently felt to be the most accurate means of evaluat
ing the carotid artery bifurcation, and is required preoperatively by
most vascular surgeons. Arterial digital subtraction angiography (DSA)
is the method commonly used. Angiography, however, is expensive and i
nvasive, with significant morbidity and mortality. Duplex scanning (DS
) has gained acceptance as a screening technique and has recently been
advocated as the sole preoperative study in several centers because i
t is non-invasive and has an accuracy that is equal to or better than
angiography. This study preoperatively evaluated 41 carotid arteries i
n 38 patients by arterial digital subtraction angiography and duplex s
canning, and the results were compared to the surgical specimen. One a
rtery was excluded because of an inadequate duplex scan, leaving 40 ar
teries studied by both techniques. Forty arteries (100%) studied by du
plex scans corresponded with the surgical specimen, whereas only 31 ar
teries (77.5%) studied by DSA corresponded with the surgical specimen.
Nine arteries (22.5%) studied by DSA had stenosis at the time of surg
ery significantly greater than predicted by DSA. Three arteries (7%) w
ere felt to be normal by DSA, but had approximately 80 per cent stenos
is by DS and at surgery. Our findings. indicate that duplex scanning a
t our institution is more accurate than arterial DSA in determining pe
rcent diameter stenosis and plaque morphology of carotid arteries.