Coronary artery plaque imaging: Comparison of black-blood MRI and 64-multidetector computed tomography

OBJECTIVE To comparatively evaluate black-blood coronary arterial wall MRI and 64-multidetector computed tomography (64-MDCT) for detection and classification of coronary artery plaques. METHODS We included 15 patients with confirmed coronary artery plaques in the proximal or middle segments of coronary arteries by 64-MDCT, who underwent black-blood coronary wall MRI at 1.5 T within 10 days. Cross-sectional coronary wall images were acquired using a 2D double-inversion-recovery, electrocardiograph-triggered, navigator-gated, fat-suppressed, turbo-spin-echo sequence on the coronary arteries with lesions from the ostium to the middle segment continuously without gap. The vessel cross-sectional area (CSA), luminal CSA, maximal wall thickness, plaque burden, contrast-to-noise ratio (CNR), and signal-to-noise ratio (SNR) were measured in each slice and subsequently compared with computed tomography angiography (CTA) images. CTA images were divided into 5-mm segments for side-by-side comparison with MRI. RESULTS Of the 15 patients, 12 were enrolled in the study. Coronary plaques were found in 46 slices on both CTA and MRI. Plaques were classified to 3 groups based on CTA: calcified plaques (n = 11), soft plaques (n = 23), and mixed plaques (n = 12). In MRI, the plaque burden, maximal wall thickness, SNR, and CNR in the coronary walls containing plaques were greater than in the normal coronary walls (0.83 ± 0.08 vs. 0.73 ± 0.08, 1.88 ± 0.51 vs. 1.51 ± 0.26 mm, 12.95 ± 2.78 vs. 9.93 ± 2.31, and 6.76 ± 2.52 vs. 3.89 ± 1.54, respectively; P < 0.05). The luminal CSA at the plaque was smaller than in normal coronary walls (2.50 ± 1.50 vs. 4.72 ± 2.28 mm2; P < 0.05). The SNR in the soft plaque was significantly greater than in calcified and mixed plaques (P < 0.05). CONCLUSIONS Coronary wall MRI can identify coronary plaques in the proximal and middle segments and has the potential to differentiate plaque types based on signal intensity.