Artery of Percheron infarct

Pathophysiology

• Artery of Percheron: anatomical variant of posterior cerebral circulation
  • Single, azygos, arterial trunk arising from P1 segment of one posterior cerebral artery
  • Supplies bilateral paramedian thalami and midbrain
• Occlusion leads to:
  • Bilateral thalamic infarction
  • Possible midbrain involvement

Diagnosis

• Clinical presentation:
  • Altered mental status (ranging from confusion to coma)
  • Vertical gaze palsy
  • Memory impairment
  • Possible oculomotor disturbances
• Differential diagnosis:
  • Top of the basilar syndrome
  • Wernicke encephalopathy
  • Viral encephalitis
  • Deep cerebral venous thrombosis

Imaging

• CT:
  • Early: may be normal or show subtle hypodensity in bilateral thalami
  • Late: bilateral paramedian thalamic hypodensities ± midbrain involvement
  • May see hyperdense thrombus within PCA. Hyperdense thrombus within the Artery of Percheron is unlikely to be seen as it is so small
• MRI:
  • DWI/ADC: early detection of acute infarction
  • T2/FLAIR: hyperintense signal in affected areas after ~4 hours
  • Characteristic "V-sign" on axial images (paramedian thalamic involvement)
• CT/MR angiography:
  • May show occlusion or absence of artery of Percheron
  • Often challenging due to small vessel size

Treatment

• Acute management:
  • Thrombolysis if within time window and no contraindications
  • Mechanical thrombectomy in select cases where thrombus is present in larger artery (PCA or basilar artery)
• Secondary prevention:
  • Antiplatelet therapy or anticoagulation based on etiology
  • Risk factor modification (hypertension, diabetes, hyperlipidaemia)

Differential diagnosis