Vessel wall magnetic resonance imaging in acute ischemic stroke: effects of embolism and mechanical thrombectomy on the arterial wall.

BACKGROUND AND PURPOSE: The aim of the study was to determine the effects of thromboembolism and mechanical thrombectomy on the vessel wall magnetic resonance imaging (VW-MRI) appearance of the intracranial arterial wall. METHODS: This was a cross-sectional study of consecutive patients with acute intracranial arterial occlusion who underwent high-resolution contrast-enhanced VW-MRI within days of stroke presentation. For each patient, we categorized arterial wall thickening and enhancement as definite, possible, or none using contralateral arteries as a reference standard. We performed χ(2) tests to compare the effects of medical therapy and mechanical thrombectomy. RESULTS: Sixteen patients satisfied inclusion criteria. Median time from symptom onset to VW-MRI was 3 days (interquartile range, 2 days). Among 6 patients treated with mechanical thrombectomy using a stent retriever, VW-MRI demonstrated definite arterial wall thickening in 5 (83%) and possible thickening in 1 (17%); there was definite wall enhancement in 4 (67%) and possible enhancement in 2 (33%). Among 10 patients treated with medical therapy alone, VW-MRI demonstrated definite arterial wall thickening in 3 (30%) and possible thickening in 2 (20%); there was definite wall enhancement in 2 (20%) and possible enhancement in 2 (20%). Arterial wall thickening and enhancement were more common in patients treated with mechanical thrombectomy than with medical therapy alone (P=0.037 and P=0.016, respectively). CONCLUSIONS: Mechanical thrombectomy results in intracranial arterial wall thickening and enhancement, potentially mimicking the VW-MRI appearance of primary arteritis. This arterial wall abnormality is less common in patients with arterial occlusion who have been treated with medical therapy alone.