High-resolution MRI may be used to monitor the progression of human carotid atherosclerosis by measuring the lumen and wall area changes over time. The purpose of this study was to analyze the precision of quantitative measurements of lumen and wall areas. Two independent MR scans near the carotid bifurcation were conducted on eight patients within 2 weeks. The error of lumen area measurement was 6. 2%, 9.2%, and 9.7% for T(1), proton density, and T(2)-weighted images, respectively, and the error of wall area measurement was 10. 8%, 10.9%, and 12.0%. The precision of area measurement correlates strongly with image quality.