Abstract 48: High-Resolution Vessel Wall Imaging of Cryptogenic Stroke: A 7T MRI Study

Abstract

Background: High-resolution vessel wall imaging (HR-VWI) has emerged as a useful tool for characterization of intracranial vasculopathic processes. HR-VWI allows better characterization of the arterial wall and may aid in the identification of atherosclerotic plaques, intra-arterial hemorrhages such as in the case of dissections and/or increased contrast enhancement such as in vasculitis. 7T HR-VWI may provide additional information in the identification of stroke mechanism in patients with cryptogenic stroke. Methods: Patients with cryptogenic stroke were prospectively imaged with a 7T scan. Strokes were determined to be cryptogenic after an extensive diagnostic work-up was completed. T1-weighted (pre- and post-contrast), T2-weighted, TOF and SWAN sequences were obtained. Demographic and clinical information was gathered from electronic medical charts. Results: Seventeen patients were included. Mean age was 57.8 ± 16.3 years-old, and 10 (58.8%) were women. HR-VWI determined the etiology of AIS in all subjects: 12 (70.6%) intracranial atherosclerotic disease (ICAD), 3 small-vessel disease and 2 arterial dissections. Inter-observer agreement was κ = 0.92. Plaque enhancement was identified in 14 cases, and intraplaque hemorrhage in 1 case of arterial dissection. In a patient with angiography suggestive of Moyamoya disease, HR-VWI determined the presence of diffuse ICAD as the underlying cause of stroke. Conclusion: HR-VWI may be used in patients with cryptogenic stroke to identify the etiologic mechanism and guide treatment. Figure: Axial-DWI (A) shows an acute right-medullary infarct (arrow). (B) Right-VA stenosis (arrow) on CTA. 7T axial-SWAN (C) reveals focal-susceptibility (arrowhead) and intra-vessel hemosiderin (arrow) suggestive of IPH. Axial-T1 pre-contrast (D), post-contrast (E) and sagittal MPR (F) images show eccentric thickening/enhancement of right-VA (arrowheads), compared to normal-appearing left-VA (arrows D-E).