Diagnostic utility of delayed cerebral angiography in suspected artery of Percheron infarction presenting as bilateral paramedian thalamic infarction: A case report

The artery of Percheron (AOP) is a rare anatomical variant in which a solitary perforating artery arising from a unilateral posterior cerebral artery supplies both paramedian thalami, with or without the rostral midbrain. Occlusion of the AOP results in a characteristic pattern of bilateral paramedian thalamic infarction; however, diagnosis is often challenging because the responsible vessel is rarely visualized on routine vascular imaging. A 68-year-old man was admitted to our hospital with severe disturbance of consciousness. On admission, his Glasgow Coma Scale score was E1V1M4 and his National Institutes of Health Stroke Scale score was 40. Magnetic resonance imaging demonstrated acute bilateral paramedian thalamic infarctions. Magnetic resonance angiography (MRA) did not clearly visualize the artery of Percheron; a small perforating branch arising from the left P1 segment appeared poorly visualized or interrupted, although this finding could reflect the spatial-resolution limitations of MRA. Given the characteristic bilateral paramedian thalamic infarct pattern, artery of Percheron infarction was suspected. The patient was treated conservatively with dual antiplatelet therapy and rehabilitation. After his systemic condition had stabilized and his level of consciousness had improved, digital subtraction angiography (DSA) was performed on hospital day 30 to reassess the posterior circulation and perforating arterial anatomy. DSA demonstrated a perforating artery arising from the left P1 segment and coursing toward the bilateral paramedian thalami, anatomically consistent with the artery of Percheron. Based on the characteristic infarct distribution together with the angiographic anatomy, artery of Percheron infarction was considered highly likely, although the angiographic finding did not directly prove that this vessel had been the acute culprit. After 45 days of hospitalization, the patient was transferred to a rehabilitation hospital; he was able to communicate verbally but remained wheelchair dependent, with a modified Rankin Scale score of 4. This case highlights the potential diagnostic value of delayed DSA in selected patients with suspected artery of Percheron infarction. Delayed angiography may provide useful anatomical information after the patient’s clinical condition has stabilized; however, the angiographic findings should be interpreted together with the characteristic infarct distribution rather than as direct proof of the acute culprit vessel.