Stroke is a major cause of disability and death each year in the Unite
d States. Most cases result from atherosclerotic disease at the caroti
d bifurcations. The risk of such events can be reduced by carotid enda
rterectomy in both symptomatic and asymptomatic patients with severe o
cclusive disease documented by imaging studies. A noninvasive means of
determining the degree of stenosis is desirable due to the morbidity,
mortality and cost associated with catheter angiography. At the prese
nt lime the main role of MRA is as a screening test to determine who s
hould undergo catheter angiography. (C) 1997 WiIey-Liss, Inc.