AbstractWe hypothesized a difference in the spatial distribution of intracranial vessel wall enhancement between CNS vasculitis and risk factors for intracranial atherosclerotic disease (ICAD). Fifty-five vessel wall MR imaging (VWI) exams were included in this retrospective observational study. Intracranial arteries were evaluated for vessel wall enhancement by branching pattern (e.g., primary, secondary, and tertiary segments). Demographic and laboratory data as well as ICAD risk factors, including a diagnosis of hypertension, were collected. A diagnosis of primary angiitis of the CNS (PACNS) was confirmed by biopsy or clinical assessment by a stroke neurologist. Univariate and multivariate Poisson regression models were fit for the outcomes. In multivariate analyses, hypertension showed significant associations with primary (β = 1.31, 95% CI 0.78–1.88, p < 0.0001) and secondary (β = 1.15, 95% CI 0.29–2.18, p = 0.05) segments, contrasting with PACNS which showed a distal spatial distribution with significant associations with secondary (β = 0.77, 95% CI 0.14–1.39, p = 0.05) and tertiary (β = 1.34, 95% CI 0.68–2.01, p < 0.0001) segments. Our results suggest the spatial distribution of vessel wall enhancement is an important consideration when interpreting VWI exams, particularly in patients with a comorbid diagnosis of hypertension. Given the global prevalence of hypertension, these results are impactful and may improve image interpretation of VWI in stroke patients.