Noninvasive assessment of carotid artery disease.

Noninvasive methods of detecting carotid disease were developed to avoid the morbidity and occasional mortality associated with cerebral angiography. The tests developed are of the following two types: direct, which uses imaging or the detection of flow disturbances to identify disease at the bifurcation, and indirect, which infers the presence of bifurcation disease by detecting changes at a remote site. The initial goal of only detecting disease has now been broadened, with this technology being used to address important clinical and epidemiologic questions such as the natural history of carotid bifurcation disease. The recognition of these important contributions has been compounded, however, by the large number of tests that are available, producing the problem of deciding which test or tests should be used for a particular patient. The use of multiple tests avoids the deficiencies of single tests but compounds medical costs. For a cost-effective single form of testing for all circumstances, duplex scanning methods offer the greatest possibility of detecting all degrees of disease.