Basilar artery thrombosis diagnosed by MR imaging.

Dysarthria, headache, and numbness on the left side developed suddenly in a 70-year-old woman with a history of hypertension , diabetes, and posterior fossa transient ischemic attacks. In 48 hours, the patient became stuporous and had left hemiparesis. On arrival , she was comatose, with pupils in midposition and light-fixed; oculocephalic responses were unobtainable. CT was negative. MR showed lesions in the occipital lobes and in the lower part of the basilaris pontes , hypointense to the normal brain on T1-weighted images and hyperintense on T2-weighted images. Increased signal on T1weighted images was observed in the basilar artery in axial and sagittal views, compatible with thrombosis or slow blood flow (Fig. 1 ). The patient died 5 days later. At autopsy, the basilar artery had an organized thrombus and atheroma within its lumen.