Bilateral thalamic infarcts

Case Discussion

Thalamic infarcts are generally asymmetric and due to multiple emboli or small vessel ischemia. Bilateral thalamic infarction is uncommon ¹. Prognosis is thought to be poor, especially if associated with midbrain infarction ². This relates to persistent cognitive and psychiatric manifestations rather than mortality and recovery from motor deficit ³. Causes include:

• artery of Percheron occlusion ¹
• cerebral venous thrombosis ⁴ 
• top of the basilar syndrome

The blood supply of the thalamus is predominantly from the posterior cerebral artery. There are 4 major vascular territories of the thalamus supplied by the tuberothalamic, inferolateral, paramedian, and posterior choroidal vessels ⁵. There is wide variability among individuals. Vascular anatomical variations are documented and include the "artery of Percheron". This uncommon anatomical variant describes a single dominant thalamomesencephalic artery supplying the bilateral medial thalami ⁶.

Venous drainage of the thalamus is via the thalamo-striate veins draining into the internal cerebral vein and perforating veins draining into basal veins. Both eventually drain into the great cerebral vein prior to drainage into the venous sinuses ⁷. 

It was unclear whether an artery of Percheron was present in this individual as they did not proceed to MRA to further characterize the cerebral vasculature.