Dynamic Behavior of Carotid Arteries Determined by Black-Blood Cine MR Imaging: Potential Plaque Vulnerability Indicators

BACKGROUND: Plaque rupture is influenced by both plaque components and the dynamic behavior of the arterial wall. This study aimed to characterize dynamic changes in carotid lumen and wall using magnetic resonance black blood cine imaging and to determine their value in discriminating plaque vulnerability. METHODS: Patients with symptomatic carotid atherosclerotic stenosis scheduled for carotid endarterectomy were recruited and underwent black blood cine imaging. Histological slices were used to identify intraplaque hemorrhage, lipid-rich necrotic core, calcification, loose matrix, and fibrous cap rupture, and were matched with magnetic resonance images. Dynamic changes in lumen area, wall area, normalized wall index (NWI), and maximum wall thickness were calculated, while static measurements were derived by averaging these parameters over cardiac phases. These measurements were compared using independent t test or Mann-Whitney U test, depending on data normality. Logistic regression and receiver operating characteristic analyses were conducted to discriminate fibrous cap rupture and to distinguish symptomatic status. RESULTS: Eighty magnetic resonance cine slices from 29 patients (mean age, 64.9±7.6 years; 22 males) were matched with histology. Slices with intraplaque hemorrhage ( P =0.019) or lipid-rich necrotic core ( P =0.016) exhibited lower NWI changes. Maximum wall thickness changes were higher in slices with loose matric ( P =0.032) but reduced in slices with calcification ( P =0.036). Maximum wall thickness changes were protective against fibrous cap rupture (odds ratio, 0.871; P =0.008; area under the receiver operating characteristic curve, 0.765). Symptomatic arteries showed lower maximum wall thickness, wall area, and NWI changes, but higher lumen area changes ( P <0.05). Static lumen area and NWI were significantly altered in slices with intraplaque hemorrhage, lipid-rich necrotic core, or loose matrix ( P <0.05), but static measurements showed no significant association with fibrous cap rupture. In discriminating symptomatic from asymptomatic arteries, combining NWI and lumen area changes achieved an area under the receiver operating characteristic curve of 0.946, whereas static NWI reached an area under the receiver operating characteristic curve of 0.971. CONCLUSIONS: Dynamic changes assessed by magnetic resonance black blood cine imaging are associated with plaque components, fibrous cap rupture, and symptomatic status, suggesting their potential as quantitative markers of plaque vulnerability.