BILATERAL INFARCTION IN THE ANTERIOR CEREBRAL-ARTERY VASCULAR TERRITORY DUE TO AN UNUSUAL ANOMALY OF THE CIRCLE OF WILLIS

Background Bilateral infarction in the anterior cerebral artery vascul ar territory is rare and usually results from rupture of an aneurysm o f the anterior communicating artery. In the case of an anomaly of the anterior part of the circle of Willis, thrombosis also may lead to bil ateral infarction. Case Description A 73-year-olh right-handed man pre sented with a complete loss of communicative behavior and an almost co mplete quadriplegia. Tc-99m-hexamethylpropylene-amine oxime single-pho ton emission-computed tomography (HMPAO SPECT) of the brain showed a ' 'horseshoe'' image, reflecting bilateral perfusion defects in areas su pplied by the anterior cerebral arteries. Postmortem examination of th e brain revealed an unusual anomaly of the circle of Willis in which t he postcommunicating part of the right anterior cerebral artery was ab sent.Conclusions In our patient a unique developmental anomaly of the circle of Willis indirectly contributed to bilateral infarction in the territory of the anterior cerebral artery. The patient's neuropsychol ogical profile, dominated by akinetic mutism, was highly suggestive of involvement of the receptive language modalities. For the first time, Tc-99m-HMPAO SPECT of the brain revealed a horseshoe image in bilater al infarction in the territory of the anterior cerebral artery.