Comparison of gadolinium-enhanced cardiovascular magnetic resonance angiography with high-resolution black blood cardiovascular magnetic resonance for assessing carotid artery stenosis

Purpose: Carotid angiography is used to assess stroke risk, but it cannot reliably characterize plaque burden because the vessel remodels during plaque formation. High-resolution black blood cardiovascular magnetic resonance (BBCMR) depicts the outer wall thereby providing a truer estimate of plaque size. We compared carotid stenosis by gadolinium enhancement cardiovascular magnetic resonance angiography (CMRA) versus high-resolution BBCMR. Methods: Twenty-four subjects (M:F = 20:4; ages 57-83 years) with carotid atherosclerosis underwent CMRA and transaxial BBCMR through the stenosis. Area and diameter stenosis measurements by NASCET criteria using CMRA images were compared to area stenosis measurements based on outer wall and lumen contours drawn on corresponding BBCMR images. Results: Area stenosis by CMRA correlated with area stenosis by BBCMR (r = 0.77; 95% CI: 0.58, 0.89). BBCMR values exceeded corresponding CMRA area measurements in 20 of 24 cases, with the remainder being highly stenotic (> 90%). Conclusion: CMRA yields lower estimates of luminal narrowing compared to BBCMR, which delineates the outer wall and accounts for vascular remodeling. BBCMR could serve as a new measure of narrowing to guide management, but prospective studies are needed to better understand the clinical implications of this new scale of disease.