Quantitative evaluation using the plaque/muscle ratio index panels predicts plaque type and risk of embolism in patients undergoing carotid artery stenting

Abstract

Objective: We sought to use a magnetic resonance (MR) plaque imaging technique to establish the plaque/muscle ratio (PMR) index panel to identify vulnerable plaques in subjects undergoing carotid artery stenting (CAS).

Methods: Between 2008 and 2010 we treated 69 patients (71 lesions) by elective carotid endarterectomy (CEA) and 35 patients (36 lesions) by CAS. All patients underwent preoperative MR plaque imaging and the ratio of plaque signal intensity to the sternocleidomastoid muscle was calculated. In the CEA group, we categorized the histopathological findings made on the surgical specimens. In the CAS group, we assessed the post-procedure diffusion-weighted images.

Results: PMR index panels for each plaque type were created using the cut-off value obtained from the receiver operating characteristic (ROC) curves of each plaque type. The probability of each of the four plaque types on each panel was assessed by Fisher's exact test. Multinomial logistic regression analysis of the DWI-positive findings determined significant probability (p=0.042).

Conclusion: The results of this study suggest quantitative evaluation using the PMR index panel has a probability to predict both the plaque type and risk of embolism in patients being considered for treatment with CAS.

Keywords: Atherosclerosis; Carotid artery stenting; Carotid endarterectomy; MR plaque image; Pathology; Plaque/muscle ratio.