Identifying clinically relevant carotid disease.

With the advent of magnetic resonance angiography (MRA) the diagnosis of carotid artery disease has clearly become a polymodal process, one that can be done by several methods. Twentyfive years ago x-ray arteriography (XRA) was the only practical test for carotid stenosis, and it was performed primarily by direct carotid puncture. Today not only can we also assess the carotid artery using noninvasive ultrasound and magnetic resonance techniques, but each modality can be applied in several different ways. In addition, preliminary studies suggest that spiral computed tomography for carotid evaluation is a promising addition to the noninvasive armamentarium. The North American Symptomatic Carotid Endarterectomy Trial (NASCET) has convinced skeptics that identifying and operating on appropriately severe common carotid bifurcation lesions can lead to a risk reduction for stroke. Attention now focuses on which methodologies are the best for identifying clinically relevant carotid artery disease. This investigative process is necessary, for one cannot — nor will the health-care system in the future —allow multiple costly diagnostic studies to select a patient for carotid endarterectomy. In this issue of Stroke a neuroradiological and vascular surgical research team from the Hospital of the University of Pennsylvania (HUP) reports its blinded-reader comparison of MRA and duplex ultrasonography (DUS) in the diagnosis of carotid artery luminal diameter stenosis in the range of 70% to 99%. The investigators report that the sensitivity and specificity of MRA and DUS, relative to XRA, are not significantly different for distinguishing surgical and nonsurgical degrees of stenosis, but MRA has some advantages as a "screening" test.