Abstract WP162: Impact of Carotid Artery Remodeling by T1 weighted MR Imaging for the Assessment of Plaque Vulnerability in High-grade Carotid Stenosis

Abstract

Background- The relationship between coronary artery remodeling and plaque vulnerability has been described on the basis of symptomatology and histology. However, the association with carotid artery remodeling has not been explored in detail. The aim of this study was to validate the relationship between carotid artery remodeling and plaque vulnerability by comparing the degree of outward remodeling calculated using 3D inversion-recovery-based T1-weighted imaging (magnetization-prepared rapid acquisition gradient-echo [MPRAGE]) with the symptomatology and histology of plaques extracted during carotid endarterectomy (CEA). Methods and Results- Sixty-one patients with high-grade carotid stenosis who underwent CEA and whose plaque could be examined were included. The average rate of stenosis as per the NASCET criteria was 79.8%. The carotid remodeling index (CRI) was determined by measuring the external cross-sectional vessel area (CSVA) of the maximum stenosis of the internal carotid artery (ICA) and dividing it by the external CSVA of the distal ICA unaffected by atherosclerosis using MPRAGE imaging. The relationship between the CRI and plaque vulnerability was evaluated on the basis of symptomatology and histology. The CRI was significantly higher in symptomatic patients than in asymptomatic patients (1.98 ± 0.26 vs. 1.68 ± 0.24, p < 0.0001). A higher CRI was positively correlated with the necrotic core area (r = 0.568, p < 0.0001) as well as significantly associated with severe intraplaque hemorrhage (p < 0.0001) and the prevalence of cap inflammation with macrophage (p = 0.03) and lymphocyte (p = 0.01) infiltration. Conclusion- These results validate the relationship between carotid artery remodeling and plaque vulnerability in high-grade carotid stenosis. MPRAGE imaging is effective to assess plaque vulnerability in terms of the CRI in addition to the signal intensity of carotid plaques.