Bilateral Symmetrical Thalamic Lesions: An Infarction Involving the Artery of Percheron

Abstract

The artery of Percheron is a rare anatomical variant artery that supplies the bilateral thalami and midbrain. An acute occlusion of the vessel will lead to the presentation of a bilateral thalamic stroke syndrome. The classical presentation includes somnolence and a reduced level of consciousness. Therefore, this clinical entity often goes unrecognized and diagnoses are usually delayed due to the ambiguity of presenting symptoms. We report a case of a man presenting with an acute onset of drowsiness, later diagnosed with a bilateral thalamic infarct only days later due to the vague clinical symptoms. We also highlighted several key learning points from this case and emphasized the importance of recognizing this syndrome.

Keywords: Artery of Percheron; Bilateral Thalamic Stroke; Confusion; Magnetic Resonance Imaging.

Figure 1

Plain CT brain showing no evidence of any acute infarction.

Figure 2

MRI brain images. (a) Hyperintensities at bilateral thalami on T2WI. (b) Hyperintensities at bilateral thalami on axial fluid-attenuated inversion recovery. (c) Hyperintensities at bilateral thalami diffusion-weighted imaging. (d) Apparent diffusion coefficient showing hypointensities at bilateral thalami, suggesting an acute ischemic infarct.

Figure 3

Schematic diagram illustrating the normal anatomical arterial supply to the bilateral thalami (left) versus the variant anatomy (right).