Abstract 140: High Intensity Signals on Mip Images of Carotid Atherosclerotic Plaques Detected by Routine Three Dimensional Magnetic Resonance Angiography Are Associated With Ischemic Strokes

Abstract

Background: Carotid artery stenosis is one of the major causes of ischemic strokes. Carotid intraplaque hemorrhage (IPH) has been associated with accelerated plaque growth, luminal narrowing and development of symptomatic events. Maximum intensity projection images are easily reformatted from four to five minute, routine, clinical TOF sequences. The aim of this study was to evaluate the relationships between high intensity signal (HIS) in carotid plaques on MIP images detected by routine three dimensional magnetic resonance imaging (3D-TOF MRA) and ischemic strokes. Materials and Methods: Sixty patients with carotid stenosis ≥ 50% (North American Symptomatic Carotid Endarterectomy Trial criteria) were included. Carotid IPH was defined as the presence of HIS in carotid plaques on MIP images detected by 3DTOF MRA using the criteria previously we reported. We analyzed the relation between the presence of HIS in the plaques and prior ischemic strokes defined as ischemic lesions on diffusion weighed images of the brain. Results: HISs in carotid plaque were present in 27 (44%) of 61 carotid arteries in 60 patients. Prior ipsilateral ischemic strokes occurred more frequently in HIS positive group (17 of 27, 63%) than HIS negative group (3 of 34; 9%) [p<0.001]. In multivariate logistic regression analysis, HIS was the only independent predictor of prior ischemic strokes after being adjusted by age, cardiovascular risk factors, degree of stenosis and history of ischemic heart disease [Odds ratio: 23.0 (95%CI: 5.1 - 103.1), p<0.001]. Conclusions: HISs in carotid plaques on 3DTOF-MRA MIP images are the only independent determinant of prior ischemic strokes, and they can potentially provide a reliable risk stratification of carotid plaques.