Whole-Plaque Adventitial Enhancement on Contrast-Enhanced MRI DANTE T1-SPACE as a Marker of Carotid Plaque Vulnerability

BACKGROUND: Neovascularization contributes to plaque vulnerability in carotid artery stenosis. We aimed to assess the association between adventitial enhancement, which reflects neovascularization, on contrast-enhanced magnetic resonance imaging (MRI), and carotid plaque volume and clinical outcomes. METHODS: We retrospectively analyzed 72 patients with 75 carotid plaques who underwent preoperative contrast-enhanced MRI using a delay alternating with nutation for tailored excitation-prepared T1-weighted turbo spin echo (DANTE T1-SPACE) sequence at Kyoto University Hospital (April 2019-March 2025). Adventitial enhancement was visually graded across the entire lesion on postcontrast DANTE T1-SPACE as category 0 (no enhancement), category 1 (<50% of outer wall circumference), or category 2 (≥50%). Plaque volume was measured from precontrast DANTE T1-SPACE. Clinical outcomes included symptomatic events and ipsilateral cerebral ischemic lesions. Intraplaque hemorrhage (IPH) presence and volume were also evaluated. RESULTS: Of the 75 plaques, 9 were category 0, 40 category 1, and 26 category 2. The proportion of either symptomatic plaques or plaques with cerebral ischemic lesions increased across categories: 11% (n = 1), 50% (n = 20), and 62% (n = 16) (P = 0.018). Mean plaque volumes were 0.59, 0.67, and 0.88 mL, respectively (P = 0.004). No significant trend was seen in IPH frequency or volume. Among plaques without IxPH, volume still increased across categories: 0.27, 0.60, and 0.92 mL (P = 0.005). CONCLUSIONS: Whole-lesion adventitial enhancement on DANTE T1-SPACE MRI may serve as a noninvasive imaging biomarker of plaque burden and vulnerability for risk stratification in carotid artery stenosis.