Abstract 2244: Noncontrast T1-Weighted Cardiovascular Magnetic Resonance Coronary Plaque Imaging: Comparison with Multi-Slice Computed Tomography and Intravascular Ultrasound
The properties of hyperintense plaque (HIP) on noncontrast T1-weighted (T1W) CMR were examined by using both multi-slice computed tomography (MSCT) and intravascular ultrasound (IVUS). Vulnerable carotid plaques contained either lipid-rich necrotic cores or intra-plaque hemorrhaging are usually visualized as hyperintense signal on T1W magnetic resonance imaging (MRI). Recently, such vulnerable coronary plaques also have been successfully visualized as hyperintense signal on noncontrast T1W cardiovascular magnetic resonance (CMR). Of thirty-eight patients with angina pectoris who had been detected ≥75% stenosis on MSCT underwent noncontrast T1W CMR, 25 patients who were observed by IVUS (18 showed HIP, 7 showed non-HIP) were enrolled. The PMR (signal intensity of plaque-to-muscle ratio) was significantly higher in HIP than in non-HIP (1.70±0.71 vs. 0.90±0.08, p=0.0081). HIP had a significantly higher frequency of positive remodeling on both MSCT (88.9% vs. 0%, p<0.0001) and IVUS (94.4% vs. 14.3%, p<0.0001), spotty calcification (88.9% vs. 50.0%, p=0.0422) and ultrasound attenuation (100% vs. 14.3%, p<0.0001), while significantly lower CT density (−23.2±20.7 HU vs. 9.6±20.5 HU, p=0.0016) than non-HIP. As a result, the frequency of transient slow flow phenomenon was significantly higher in HIP than in non-HIP (83.3% vs. 14.3%, p=0.0012). In HIP, the typical pattern was ultrasound attenuation, associated with a remarkable negative CT density and positive remodeling. These results suggest that the HIP as generated by noncontrast T1W CMR may therefore represent particularly vulnerable plaque. Therefore, CMR may allow for the noninvasive identification of high-risk coronary atherosclerotic lesions before the development of catastrophic events.