The patient arrived at the ER with a loss of consciousness. She had multiple old left MCA and right ACA territory old infarcts and known SLE and antiphospholipid syndrome. This patient has a higher risk of ischemic stroke. Cardiogenic (atrial fibrillation) or atherosclerotic embolus could also be in the background.

Bilateral thalamic and mesencephalic infarcts are typical for Percheron territory infarct. Basilar artery occlusion ( top of the basilar syndrome) could be in the differential. Still, there was no basilar artery occlusion on the CTA, and the lack of PCA involvement also supports the Percheron territory infarction.

Artery of Percheron is a rare anatomical variant when a solitary artery supplies both thalami and the midbrain bilaterally.