Background and purpose: Transient ischemic attack may rarely reveal an intracranial artery occlusion. We analyzed acute magnetic resonance imaging (MRI) patterns and early outcome after reperfusion therapy in these cases.
Method: Clinical and imaging data were taken retrospectively from our comprehensive stroke center registry. Two MRI patterns were determined. Pattern A: full mismatch with negative diffusion-weighted imaging (DWI) and perfusion defect. Pattern B: large mismatch with positive DWI and perfusion defect. MRI-derived collateral flow maps were automatically generated from the raw of dynamic susceptibility contrast MRI. Patients were treated either by recombinant tissue plasminogen activator (rtPA) alone or in combination with mechanical thrombectomy.
Results: From October 1, 2010 to May 15, 2016, 1,019 patients were admitted and treated by t-PA within 4.5 hours of stroke onset of them; 14 had a transient ischemic attack (TIA) within the 6 hours preceding MRI. Perfusion imaging was performed in 11 patients. An arterial occlusion was found in all of them, 11 patients had a distal anterior circulation occlusion, whereas 3 patients (21%) had a proximal occlusion. According to MRI, 6 patients showed pattern A, whereas 5 patients had pattern B. Good collaterals were observed in 10 patients (6 patients with grade 3 and 4 patients with grade 4), whereas 1 patient had poor collaterals (grade 2). The day 1 National Institutes of Health Stroke Scale median was 0. Modified Rankin Scale median at 3 months was 0.
Conclusion: TIAs may reveal acute intracranial artery occlusion. Acute MRI may able to assist in therapeutic decision.
Keywords: MRI; TIAs; arterial occlusion; collateral flow.
© 2018 by the American Society of Neuroimaging.