Bitalamic acute stroke: artery of Percheron

A 44-year-old man without medical history was admitted to the emergency room in a coma. He had not reported work and was discovered lying on the ground of his home in the evening by his brother. The initial Glasgow Coma Scale score was a 5. Head CT study without contrast agent injection was performed and revealed well delimited bithalamic central hypodensities (Fig. A1, axial view, stars in the paramedian thalami), suggestive for sub-acute ischemic lesions. MRI series showed high diffusion and FLAIRweighted signal of the two paramedian thalami and of the internal side of the left occipital lobe confirming recent ischemic lesion (Fig. A2, FLAIR-weighted frontal view, Fig. B1, Diffusion-weighted axial view). Time-of-flight (TOF) magnetic resonance angiography well demonstrated distal amputation of the left posterior cerebral artery (PCA), due to acute thrombosis or embolic occlusion (Fig. B2, arrow on the normal right PCA, arrowheads on the amputated left PCA). Bithalamic infarction was attributed to an anatomic variation: a common trunk for the two thalamic paramedian arteries, concerned by the PCA obstruction