Percheron artery infarction: A case that developed during coronary angiography with a normal initial diffusion study

Introduction: The artery of Percheron is a variant, seen in 4–12% of cases, in which a single trunk supplies both paramedian thalami and often the rostral midbrain. Its occlusion causes bilateral thalamic infarction and presents with acute impairment of consciousness, ophthalmoparesis, and cognitive impairment. Its rarity, and the fact that it is often undetectable on computed tomography (CT), can delay diagnosis. We report a patient who developed altered consciousness during elective coronary angiography (CAG) and had normal initial imaging.Case: A 49-year-old man with a history of hypertension was evaluated after his level of consciousness declined during elective CAG. Heparin had been given during the procedure and no stent was placed; he had been taking acetylsalicylic acid for one week. Diffusion MRI, brain CT, and cerebral angiography obtained in the acute phase showed no pathology. In the intensive care unit, while he was alert, his level of consciousness suddenly declined. On examination he was confused and partially cooperative; the pupils were isocoric but the light reflex could not be elicited bilaterally, and there were no lateralizing signs. Repeat diffusion-weighted MRI showed diffusion restriction consistent with acute infarction in the medial portions of both thalami, and Percheron artery infarction was diagnosed. Dual antiplatelet therapy was started. Over the following two days, his consciousness cleared and the light reflex returned bilaterally, and he was discharged with neurological improvement. The patient’s clinical course, neurological examination findings, and neuroradiological studies (diffusion-weighted magnetic resonance imaging (MRI), apparent diffusion coefficient (ADC) map, FLAIR, brain CT, and CT angiography) were evaluated retrospectively (Figure 1).Discussion/Conclusion: Percheron artery infarction is a rare but critically important ischemic stroke subtype that can present with acute altered consciousness. In this case, the diffusion MRI, brain CT, and cerebral angiography obtained at symptom onset were read as normal, and the diagnosis could be made only with repeat diffusion MRI. Normal early imaging does not exclude the diagnosis; the study should be repeated when clinical suspicion persists. Percheron artery infarction should be considered in the differential diagnosis of sudden altered consciousness, particularly after invasive vascular procedures.Keywords: