Acute bilateral thalamic infarction and the artery of Percheron

What is it about?

The thalami of the human brain obtain their blood supply from many perforating arteries, which exhibit complex distribution and many variations. One rare variation is the artery of Percheron that supplies the paramedian thalami bilaterally. This artery arises from the first segment of the posterior cerebral artery and gives rise to bilateral medial thalamic perforants. Occlusion of the artery of Percheron none rarely results in bilateral thalamic and mesencephalic infarctions. We describe the case of a 38-year-old male patient with a presumed occlusion of this artery in which MR imaging revealed characteristic symmetrical bilateral paramedian thalamic infarctions. The unique characteristics of this case are based on the young age of the patient, the absence of any risk factors or other diseases and even more on the rare clinical manifestations consisted of hypophonia, memory dysfunction, time disorientation and apathy.

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Why is it important?

Acute simultaneous bilateral thalamic infarcts in various vascular territories are uncommon as they represent over 0.6% of first ever acute ischemic stroke. The paramedian thalamic region is the most commonly affected location and usually the infarcts are asymmetrical . Occlusion of the artery of Percheron results in bilateral medial thalamic and rostral mesencephalic infarctions with a relatively symmetrical distribution. So when bilateral medial thalamic infarcts are found, occlusion of the artery of Percheron should be considered as the main causative factor. Castaigne et al. stated that when the artery of Percheron is occluded, the thalamic infarcts are always bilateral and medial [6]. Performing conventional angiography may not be indicated because lack of visualization of the artery does not exclude its patency as well as its occlusion. The cause of stroke in patients suffering from bilateral thalamic infarction is mainly a small artery disease and secondly an embolism from various emboligenic sources. The unique characteristics of this case were the young age of the patient, the absence of any risk factors and the inability to detect any obvious causative factor .

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