Plaque-to-artery signal intensity ratio on time-of-flight magnetic resonance angiography (TOF-MRA) as a predictor of postoperative ischemic lesions after carotid artery stenting.

Abstract

<h4>Background</h4>New ischemic lesions, which may occur after carotid artery stenting (CAS), are often clinically silent; however, they are associated with long-term functional and cognitive decline. Reliable predictors are therefore needed. We investigated whether the plaque-to-contralateral internal carotid artery (ICA) signal intensity ratio on preprocedural time-of-flight magnetic resonance angiography (TOF-MRA) predicts new ischemic lesions after CAS.<h4>Methods</h4>We retrospectively analyzed consecutive CAS procedures performed with closed-cell or mesh-covered stents between January 2014 and April 2025. The plaque-to-contralateral ICA ratio, defined as plaque signal intensity divided by the contralateral normal ICA signal intensity, was measured on axial TOF-MRA. New ischemic lesions after CAS were assessed using diffusion-weighted imaging (DWI). Associations between the plaque-to-contralateral ICA ratio and the occurrence of new DWI-positive lesions were evaluated using multivariate logistic regression and receiver operating characteristic (ROC) curve analyses.<h4>Results</h4>A total of 123 CAS procedures were performed in 116 patients (mean age, 74.3 ± 6.0 years; 84.6% male). Postprocedural DWI-positive lesions occurred in 61 procedures (48.8%). Compared with DWI-negative procedures, the DWI-positive group had a higher plaque-to-contralateral ICA ratio (0.38 ± 0.16 vs. 0.29 ± 0.15, p = 0.001), a higher rate of symptomatic stenosis (68.9% vs. 41.9%, p = 0.002), a lower prevalence of prior coronary artery disease (24.6% vs. 42.2%, p = 0.029), and older age (75.6 ± 5.7 vs. 73.0 ± 6.0 years, p = 0.012). Multivariate logistic regression analysis identified the plaque-to-contralateral ICA ratio (odds ratio [OR] per 0.1 increase, 1.48; 95% confidence interval [CI], 1.14-1.91; p = 0.003), age (OR, 1.11; 95% CI, 1.03-1.19; p = 0.006), symptomatic stenosis (OR, 3.17; 95% CI, 1.40-7.20; p = 0.006), and previous coronary artery disease (OR, 0.38; 95% CI, 0.15-0.92; p = 0.032) as independent predictors of new DWI-positive lesions. The plaque-to-contralateral ICA ratio (cutoff, 0.296) and age (cutoff, 75 years) yielded areas under the ROC curve of 0.661 and 0.646, respectively.<h4>Conclusions</h4>The plaque-to-contralateral ICA signal intensity ratio on preoperative TOF-MRA independently predicted new ischemic lesions after CAS, supporting its value for perioperative risk stratification. Because increased TOF-MRA signal is associated with intraplaque hemorrhage and inflammation, a higher ratio likely reflects greater plaque vulnerability. This objective imaging measure may help identify patients at high risk for postprocedural ischemic lesions and guide individualized interventional planning.