Abstract 95: MRI Description of an Adult Primary Angiitis of the Central Nervous System in the French COVAC Cohort

Abstract

Introduction: Primary angiitis of the central nervous system (PACNS) is a potentially severe inflammatory disease of central nervous system vessels and despite its extreme sparsity, knowledge has improved within past decades. PACNS diagnosis, however, remains challenging, mainly because of the multiple mimickers and possible differential diagnoses. Previous MRI/MR Angiography descriptions of PACNS adult patients might have become outdated Hypothesis: To report an updated overview and pictural review of MR/MRA findings in adult PACNS, determine type/distribution of parenchymal, meningeal and vascular lesions in an independent multicentric inception cohort. Methods: Patients from the French mutlicentric COVAC cohort, adults with biopsy/angiographically proven PACNS were included if they had MRI/MRA available imaging upon diagnosis for retrospective review. Systematic imaging review was performed blinded to clinical data. Results: Among the 91 enrolled patients in cohort, 60 met inclusion criteria for this study. Mean age was 45yo (±12.9). Patients presented initially with focal deficit(s) (83%), headaches (53%), cognitive disorder (40%) or seizures (38.3%). MRI was abnormal in all patients, most common finding being ischemic stroke following a small arteries distribution with multi-territorial lesions (50% of evaluated patients), with a predominant anterior distribution. 57% of parenchymal hemorrhagic lesions were hemorrhagic transformation of ischemic strokes. 26% of patients had otherwise subarachnoid hemorrhage. 42% of patients demonstrated preeminent leptomeningeal enhancement. Seven had tumor like presentation. 77% of MRA studies were abnormal revealing proximal/distal stenoses in respectively 57% and 61% of patients. Only 11 patients demonstrated a typical beading aspect on MRA. DSA unmasked distal stenotic lesions in <10% of patients with normal MRA. Discussion: We present the largest to date MRI/MRA systematically assessed cohort of adult PACNS patients, extend our current knowledge of this rare and heterogeneous disease and present an extensive analysis of MRI and MR Angiography characteristics of PACNS in adults.