Complementary roles of a noninvasive test battery and DSA in evaluating carotid artery disease

Initial comparisons of the results of digital subtraction angiography (DSA) and a battery of tests for noninvasive diagnosis of carotid artery disease indicate the two techniques are complementary, rather than competitive. DSA provides important morphologic information at the carotid bifurcation and siphon, but the images are sometimes difficult to interpret with precision. Noninvasive testing gives discrete physiologic information related to hemodynamics, but the findings are less specific for the level of the lesion in the carotid/ophthalmic system. Noninvasive tests may be more useful than DSA for determining if a lesion is hemodynamically significant and whether advanced disease shows evidence of progression on sequential studies. The noninvasive tests are not definitive procedures, but are useful in selecting patients for a contrast study. They are the initial procedure of choice for the patient with asymptomatic bruit. Depending on the clinical situation and quality of the study, DSA can sometimes be a definitive procedure, but in some situations correlative noninvasive test results are necessary to assess whether the patient is a candidate for arteriography and/or surgery.