Arjen Lindenholz

125 Intracranial Atherosclerosis Assessed with 7T MRI 5 Discussion We investigated the association between the intracranial vessel wall lesion burden assessed by using 7T MRI with dedicated intracranial vessel wall sequences and established vascular risk factors in participants with ischemic stroke or transient ischemic attack of the anterior cerebral circulation. Current data is mainly based on the assessment of luminal narrowing rather than abnormalities in the vessel wall. Our main results are threefold. First, we found that increasing age (RR, 1.02), hypertension (RR, 1.46), diabetes mellitus (RR, 1.67), and higher multivariable vascular risk score (RR, 1.01) were associated with a higher vessel wall lesion burden in the anterior circulation, and that increasing age (RR, 1.03) was associated with a higher number of enhancing lesions. Second, we found that increasing age (RR, 1.02), hypertension (RR, 1.49), higher systolic blood pressure (RR, 1.15), diabetes mellitus (RR, 1.78) and lower estimated glomerular filtration rate (RR, 1.01) were associated with vessel wall lesion burden when both anterior and posterior circulation lesions were combined. Finally, we did not find an association between smoking (RR, 1.00) and the intracranial vessel wall lesion burden. Because of heterogeneity in study populations and diagnostic methods as well as varying definitions of ICAS in previous studies, our results are difficult to compare with the literature. In these previous studies, increasing age, hypertension, and diabetes mellitus were the most consistent risk factors associated with the presence and severity of ICAS (defined as presence or degree of stenosis). 4,8 This was confirmed in our study. In previous studies, the ‘metabolic syndrome’, defined as a constellation of risk factors, was associated with strokes caused by ICAS. 8 In our study, the more elaborate composite SMART risk score was also associated with anterior circulation vessel wall lesion burden. Although smoking, dyslipidemia, and male sex have been reported as independent risk factors for ICAS in lumenography- based studies, 4,8,33 no statistically significant association between these risk factors and vessel wall lesion burden was observed in our study. A recent study that has assessed the relation between vascular risk factors and ICAS using dedicated 3T intracranial vessel wall MRI sequences was performed in a community-based population in the United States that consisted of African American and white subpopulations (with oversampling of participants with cognitive impairment and previous brain MRI). 20 Vascular risk factors were assessed at baseline in midlife and during follow-up, when intracranial vessel wall MRI was performed. In accordance with our study, the number of vessel wall lesions was only associated with hypertension and age in the white subpopulation. Smoking was associated with prevalence – not with lesion burden – of ICAS in the African American population and not in thewhitepopulation, which is consistentwith the results of our study. In contrast to our study, diabetes mellitus was associated with the prevalence of ICAS – but only