Proximal hyper-intense vessel sign on initial FLAIR MRI in hyper-acute middle cerebral artery ischemic stroke: a retrospective observational study

Background A hyper-intense vessel sign on fluid attenuated inversion recovery magnetic resonance imaging (FHV) represents slow blood flow in the cerebral arteries. Purpose To investigate the relationship between the proximal FHV (pFHV) on initial magnetic resonance imaging (MRI) and the status of the culprit vessel (stenosis, obstruction) in hyper-acute strokes affecting the territory of the middle cerebral artery (MCA). Material and Methods The study participants consisted of 105 patients presenting to the emergency department (ED) with acute MCA infarction within 4.5 h of onset of symptoms. Patients underwent brain MRI within 45 min of arrival at the ED and angiography within 2 h of arrival. Culprit vessel status and presence of a pFHV on initial MRI were investigated retrospectively. Results The pFHV was observed in 71/105 (67.6%) patients who presented with a hyper-acute MCA infarction. All patients with hyper-acute MCA infarction caused by internal carotid artery (90.6% caused by M1 occlusion, 92.9% caused by M2 occlusion) showed a pFHV on initial MRI. After logistic regression analysis, the presence of a pFHV showed significant positive correlation with large vessel occlusion (adjusted odds ratio OR 34.533, 95% confidence interval CI 9.781–121.926; P < 0.001). A pFHV was not associated with severe large vessel stenosis. Conclusion A pFHV is independently representative of the acute occlusion of intervention-eligible proximal arteries within the territory of the MCA. If a patient with a hyper-acute MCA infarction shows a pFHV, aggressive flow augmentation strategies and early activation of intervention team should be warranted for best patient outcome.