Bilateral Hypoperfusion and Normal Diffusion MR Images in a Case of Acute Embolic Stroke

Abstract

Christina Iosif a , C. Oppenheim a , C. Lamy b , J.L. Mas b , J.F. Meder a Universite Paris Descartes, Departments of a Neuroradiology and b Neurology, Sainte-Anne Hospital, Paris , France bleeding was seen, apart from a left parietal microbleed. DWI was normal while apparent diffusion coefficient (ADC) maps revealed a small region of ADC restriction (20%) in the left deep MCA territory. Bolus tracking perfusion-weighted images (PWI) showed bilateral large abnormally perfused areas: (1) in the left MCA territory (mean transit time = 133%, cerebral blood flow = 56% of normal-appearing right frontal area), corroborating the neurological deficit, and (2) in the right temporo-occipital region (mean transit time = 126%, cerebral blood flow = 54%) ( fig. 1 ). After MRI completion, global aphasia persisted (National Institute of Health Stroke Scale score = 5) and the heart rate was irregular. The laboratory tests were normal. Based on the expected language handicap in case of infarct completion and on the presence of at-risk tissue in the contralateral hemisphere, intravenous thrombolysis (6 mg of rt-PA bolus followed by infusion of 52 mg of rt-PA in 1 h) was initiated 160 min after onset. Follow-up MRI showed recanalization of the left MCA and bilateral regression of early vessel signs on FLAIR. The carotid occlusion persisted. A left deep MCA infarct and a right small insular infarct were visible, without cerebral bleeding. The language deficit progressiveA 56-year-old man with a history of paroxysmal atrial fibrillation was referred for sudden mutism and right hemiplegia. Improvement of the motor deficit occurred during transportation. Brain MRI 100 min after onset showed hyperintense middle cerebral artery (MCA) branches bilaterally on FLAIR sequence, and T 2 * hypointensities in the M1 segment of the left MCA and in a right insular branch corresponding to fresh thrombi. MR angiography revealed a left carotid and M1 occlusion. No parenchymal