Imaging the artery of Percheron: a pictorial review of associated pathology with important mimics of bithalamic abnormalities.

BACKGROUND AND PURPOSE: The Artery of Percheron (AoP) supplying bilateral paramedian thalami and rostral midbrain is a rare anatomical variant. In the event of occlusion of AoP, a characteristic pattern of ischaemia is seen, presenting as bithalamic signal abnormality on magnetic resonance imaging (MRI). However, this particular imaging finding has significant radiological and clinical overlap with other conditions, necessitating a comprehensive understanding of the imaging characteristics and potential differential diagnosis. The aim of this pictorial essay is to provide a visual documentation of varying appearances of AoP infarction on imaging and highlighting other important pathologies that may cause similar appearance.

METHODS

Retrospective collection and review of imaging from patients with confirmed AoP infarction and other pathologies causing bithalamic signal abnormalities and identify crucial imaging caveats for differentiation.

RESULTS

We present a comprehensive visual spectrum of AoP infarction patterns, including bithalamic involvement (paramedian thalamic lesions) with or without midbrain involvement. Additionally, the "V" sign, observed on FLAIR and DWI sequences, is fairly characteristic of AoP infarction. Other important vascular causes seen include top of basilar artery syndrome, internal cerebral vein thrombosis as well as neoplastic lesions including diffuse midline glioma (DMG) H3 K27-altered. Additionally various inflammatory, metabolic and infective etiologies including viral encephalitis like Japanese encephalitis can cause a similar appearance.

CONCLUSIONS

This pictorial essay demonstrates the diverse patterns of AoP infarction and emphasizes the significance of recognizing important mimics of this condition, highlighting the need for a meticulous evaluation. Improved awareness and understanding of these imaging characteristics will contribute to more effective management of patients with thalamic strokes.