New techniques in the evaluation of cerebrovascular disease.

Numerous reports in the literature indicate that various noninvasive vascular techniques can now be used to evaluate atherosclerosis at the carotid bifurcation. This article reviews noninvasive screening techniques currently available and being developed. Particular emphasis has been placed on the practicality of these techniques as well as their limitations. Our conclusions are that noninvasive techniques cannot be used as definitive screening tests for cerebrovascular disease. Although these tests are frequently useful when positive, the false negative rate of these tests would appear to be significant and variable in different hands. Nonstenotic ulcers are usually not detected and total occlusion often not differentiated from stenosis. These tests should be viewed as the beginning rather than the end result of a developing field. At present, contrast arteriography remains the definitive test to evaluate the presence and significance of extracranial cerebrovascular disease.