Characterization of Restenosis following Carotid Endarterectomy Using Contrast-Enhanced Vessel Wall MR Imaging.

Abstract

Restenosis is an important determinant of the long-term efficacy of carotid endarterectomy. Our aim was to assess the role of high-resolution vessel wall MR imaging for characterizing restenosis after carotid endarterectomy. Patients who underwent vessel wall MR imaging after carotid endarterectomy were included in this study. Restenotic lesions were classified as myointimal hyperplasia or recurrent atherosclerotic plaques based on MR imaging features of lesion compositions. Imaging characteristics of myointimal hyperplasia were compared with those of normal post-carotid endarterectomy and recurrent plaque groups. Recurrent plaques were matched with primary plaques by categories of stenosis, and differences in plaque features were compared between the 2 groups. Twenty-two recurrent lesions from 18 patients (14 unilateral and 4 bilateral) were classified as myointimal hyperplasia or recurrent plaque. Myointimal hyperplasia showed no difference in enhancement compared with normal post-carotid endarterectomy vessels (5 unilateral) but showed stronger enhancement than recurrent plaques (80.10% [SD, 42.42%] versus 56.74% [SD, 46.54%], P = .042). A multivariate logistic regression model of plaque-feature detection in recurrent plaques compared with primary plaques adjusted for maximum wall thickness revealed that recurrent plaques were longer (OR, 4.27; 95% CI, 1.32-13.85; P = .015) and more likely to involve a flow divider and side walls (OR, 6.96; 95% CI, 1.37-35.28; P = .019). Recurrent plaques had a higher prevalence of intraplaque hemorrhage (61.5% versus 30.8%, P = .048) by a χ2 test, but compositional differences were not significant in the multivariate model. Vessel wall MR imaging can distinguish recurrent plaques from myointimal hyperplasia and reveal features that may differ between primary and recurrent plaques, highlighting its value for evaluating patients with carotid restenosis.