MRI showing DWI-FLAIR mismatch in acute ischemic stroke due to left middle cerebral artery occlusion

A 49-year-old woman presented with right hemiplegia and dysarthria. The patient arrived at the emergency department 72 minutes after symptom detection. Her initial NIHSS score was 13. Brain MRI showed an acute ischemic lesion in the left MCA territory on DWI (A and B) without parenchymal signal changes on FLAIR (C and D). MRA showed occlusion of the M1 segment of the left MCA with collateral blood flow in the distal cerebral artery territory (E). Intravenous thrombolysis was started 140 minutes after symptom detection. On DSA, the left MCA was still occluded on the M1 segment (F) and was recanalized after mechanical thrombectomy with a TICI score of 3 (G). Time from symptom detection to recanalization was 189 minutes (3 hours and 9 minutes). The mRS score at three months was 0.