A 75-year old woman with atrial fibrillation presented with the acute onset of a global aphasia and right hemiplegia.

CT Scan of the brain (day 2). Note the large hypodensity involving the entire middle cerebral artery territory as well as the deeper basal ganglia. The fact that the basal ganglia are involved denotes that the infarction involved the proximal middle cerebral artery stem, before the take off of the small perforating vessels which supply the basal ganglia. Lastly, note that the left occipital lobe (posterior cerebral artery territory) is also infarcted. Although this could represent a separate embolus to the PCA, the more likely explanation is that the patient had a persistent fetal circulation on the left. In this normal anatomic anomaly, the posterior cerebral artery arises directly from the internal carotid artery.

Revised 04/22/06.
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