A case of brain infarction showing recanalization of an occluded extracranial internal carotid artery detected by carotid ultrasonography during intravenous t-PA therapy

We report an 81-year-old man who suddenly felt weakness of the right upper and lower extremities. He was admitted to our hospital within 1 hour after onset Neurological examination revealed consciousness disturbance and right hemiparesis. The National Institutes of Health Stroke Scale (hflHSS) score in the emergency room was 7. As the neurological impairment was completely resolved in the emergency room, we diagnosed the patient as having a transient ischemic attack. However, 5 hours after admission, aphasia and right hemiparesis recurred with a NIHSS score of 5, and MR angiography demonstrated occlusion of the left internal carotid artery (ICA) corresponding to hyper-intense lesions in the left frontal lobe on diffiasion-weighted imaging. We treated the patient with intravenous tissue plasminogen activator (IV t-PA) while monitoring the left ICA using carotid ultrasonography. Initially, the blood flow velocity in the left ICA showed an occluded pattern, and then 30 minutes after starting IV t-PA, the left ICA demonstrated diastolic flow velocity. After several minutes, the flow pattern in the left ICA changed to a normal one. The neurological manifestations showed dramatic improvement, with a NfflSS score of 1. Carotid duplex ultrasonography appears to be a promising tool for observation of recanalization after ICA occlusion.