Abstract 5131: Prediction of Silent Ischemic Lesions After Carotid Artery Stenting Using Integrated Backscatter Ultrasound and Magnetic Resonance Imaging

Abstract

Background: The purpose of this study was to determine whether integrated backscatter (IBS) ultrasound and black-blood magnetic resonance imaging (BB-MRI) can predict the risk of cerebral embolism after carotid artery stenting (CAS). Methods: We performed quantitative analysis of plaque characteristics in carotid arteries using IBS ultrasound (SONOS 7500) and BB-MRI before CAS in 50 patients. We measured IBS values and the signal intensity ratio (SIR) of carotid plaques to that of adjacent sternocleidomastoid muscle from T1-weighted images. We performed diffusion-weighted MRI of the brain before and after CAS. Results: In the patient group that was positive (n =19) for newly appearing ipsilateral silent ischemic lesions (NISIL), relative lipid and intra-plaque hemorrhage area (%LHA) evaluated by IBS analysis (60.2±23.4% and 35.3±19.2%, p<0.001) and SIR (1.40±0.19 and 1.18±0.25, p<0.01) in most stenotic lesions were higher than in the NISIL-negative group (n =31). From the analysis of ROC curves, 50% of the %LHA and an SIR of 1.25 were the most reliable cutoff values for predicting NISIL with the sensitivity of 68% and the specificity of 87% in the IBS analysis and 84% and 68% in the BB-MRI analysis. In multivariate logistic regression analysis, the independent predictors of NISIL were SIR (p = 0.03), the serum CRP level (p = 0.04) and the %LHA (p = 0.05). Conclusions: Quantitative tissue characterization of carotid plaques using IBS ultrasound and BB-MRI was useful to predict NISIL after CAS. It is recommended that plaque components be evaluated by SIR or IBS before CAS, and carotid endarterectomy should be selected to prevent distal embolism when the %LHA is > 50% or the SIR is > 1.25.