MRI-plaqueimaging detects carotid plaques with a high risk for future cerebrovascular events

Background: High-Resolution Magnetic Resonance Imaging (MRI) represents a new technique for risk classification of carotid plaque features. MRI-Plaqueimaging allows categorization of carotid artery stenosis (CS) in distinct lesion types (I-VIII) according to a modified histological scheme based on American Heart Association (AHA) criteria. Lesion types IV-V and VI are regarded as high risk, rupture prone plaques.

The aim of this study was to prospectivly investigate wether MRI-plaque imaging can identify patients with initially asymptomatic, high-risk CS who have an increased risk for future cerebral events.

Methods: 118 patients (74 male) presenting with an initially asymptomatic high-grade CS were enrolled. Patients were imaged with a 1.5 T scanner using bilateral phased-array carotid coils. T1-, T2-, time-of-flight (TOF) and proton-density (PD)-weighted studies were obtained at baseline. The carotid plaques were classified as lesion types I-VIII according to the MRI-modified AHA criteria.

Results: Over a mean-follow-up period of 44.1 months, 15 ipsilateral ischemic cerebrovascular events occurred. Cox regression analysis revealed the presence of lesion type IV-V (95% CI, 1.21 to 9.24; P=0.02) or lesion type VI (95% CI, 1.19 to 11.77; P=0.02) to be associated with the development of subsequent cerebrovascular ischemia during follow-up. Among all other analysed cerebrovascular risk factors, only diabetes was related to the development of ipsilateral cerebrovascular events (95% CI, 1.62 to 14.12; P=0.005).

Discussion: MRI-plaqueimaging has the potential to identify patients with asymptomatic carotid stenosis who are particular at risk of developing future cerebral ischemia. MRI-based plaque imaging could improve risk stratification and selection criteria for invasive therapy in the future.