Objective--Ethnicity-based research may identify new clues to the pathogenesis of atherosclerotic disease. Therefore, we sought to determine whether carotid lesions differ between 20 Chinese and 20 Caucasian Americans by MRI.

Methods and Results--Inclusion criteria were >50% stenosis as measured by duplex ultrasound and recent symptoms attributed to carotid artery disease. The patients were imaged in 2 centers (Beijing, China and Seattle, Wash) using a standardized protocol. Both carotid arteries were reviewed quantitatively (lumen, wall, outer wall, tissue components) and morphologically (lesion types, fibrous cap status). Significant differences between the Chinese and Americans were found for the mean size of the lipid/necrotic core (13.6 versus 7.8 mm²; P=0.002), percentage of slices with calcified type VII lesions (1.6 versus 12.4%; P=0.03), and percentage of slices with early type III lesions (19.3 versus 9.3%; P=0.02). Furthermore, the mean outer wall area in the common carotid artery was larger in the Chinese population (P=0.007).

Conclusions--This pilot study suggests that composition and morphology of atherosclerotic lesions in symptomatic carotid disease differ between ethno-racial groups. Quantitative MRI-based review of carotid atherosclerosis comparing plaque morphology and composition between ethno-racial groups is feasible, and future MRI studies may improve our understanding of the pathophysiology of this disease.