Determination of Carotid Artery Atherosclerotic Lesion Type and Distribution in Hypercholesterolemic Patients With Moderate Carotid Stenosis Using Noninvasive Magnetic Resonance Imaging

Abstract

Background and Purpose— The aims of this study were to noninvasively determine carotid atherosclerotic lesion type and distribution and to evaluate the reproducibility of determining lesion types in asymptomatic patients with moderate hypercholesterolemia and moderate carotid artery (CA) stenosis using MRI. Methods— Forty-two asymptomatic patients with moderate CA stenosis underwent bilateral carotid MRI in a 1.5-T scanner using a protocol that generated 4 contrast weightings (T1, T2, proton density, and 3D time of flight). MRI-modified American Heart Association criteria were used to evaluate lesion types at 3 locations (common and internal CA [CCA and ICA, respectively] and CA bifurcation) and at the minimum lumen area. Two identical MR scans were conducted to evaluate reproducibility of lesion types. Results— Lesion types were obtained from 230 locations. Type III (39%) occurred most commonly, followed by types IV–V (25%), I–II (20%), VI (12%), and VII (4%). Type III was more commonly distributed in the CCA (n=35, 39%) and ICA (n=32, 36%). Type IV–V was more commonly distributed in the CCA (n=24, 41%) and at the bifurcation (n=21, 36%). Forty-two lesions were available at the site of minimum lumen area: type III (33%), IV–V (33%), VI (29%), and VII (5%). There was good agreement of lesion types between both MRI scans (Cohen’s κ=0.73; 95% CI: 0.65 to 0.81). Conclusions— MRI can determine lesion types reproducibly as well as the distribution of lesions in hypercholesterolemic patients with moderate CA stenosis. A wide range of lesion types, including advanced lesions, were found in these patients.