Search

Blood supply to the human thalami is complex and multiple variants exist. The artery of Percheron is one of those variants and is characterized by a solitary arterial trunk that branches from one of the proximal segments of either posterior cerebral artery and sup- plies blood to the paramedian thalami. Its occlusion results in bilateral paramedian thalamic infarction sometimes extending to the midbrain. We report a case of bithalamic infarction secondary to occlusion of the artery of Percheron. We will illustrate the complex clinical symptomatology and underscore the role of imaging, especially MRI, for diagnosis., (© 2023 The Authors. Published by Elsevier Inc. on behalf of University of Washington.)

Isolated downgaze paralysis is the most infrequent expression of vertical gaze abnormalities. Vertical eye movements are controlled by nuclei and circuits located in the thalamic-mesencephalon region, and more particularly the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF). The Artery of Percheron (AP) is a rare vascular anatomic variation that supplies the paramedian region of the thalami and the rostral portion of the mesencephalon. We present a unique case of isolated downgaze paralysis caused by AP ischemia., (© 2023 The Authors. Published by Elsevier Inc. on behalf of University of Washington.)

The thalamus is predominantly supplied by multiple small vessels originating from the posterior communicating artery and the P1 and P2 segments of the posterior cerebral artery (PCA). The artery of Percheron (AOP) is a rare anatomical variant of arterial supply to the thalamus. This single thalamic perforating branch supplies the bilateral thalamus so that occlusion results in a characteristic cerebral infarction. Herein, we report a case of posterior cerebral artery occlusion that developed into an AOP infarction. A 74-year-old man, who had undergone coronary artery bypass grafting 5 days previously presented with sudden consciousness disorder and tetraplegia, and was admitted to our hospital. Magnetic resonance imaging (MRI) revealed a hyper-intense area in the bilateral paramedian thalamus on diffusion-weighted imaging and a deficit of the left PCA on MR angiography (MRA). The patient was diagnosed with cardiogenic cerebral embolism, and immediately underwent mechanical thrombectomy (MT), thereby complete recanalization was obtained. Post-procedural MRI showed no new lesions, and the left PCA could keep patency. His consciousness disorder and tetraplegia improved; however, cognitive impairment and vertical gaze palsy persisted as sequelae. To the best of our knowledge, such cases have not been previously reported. Additionally, in this case, we were able to identify an AOP on digital subtraction angiography, which was considered to be the responsible artery., (© 2022 The Authors. Published by Elsevier Inc. on behalf of University of Washington.)

The Artery of Percheron (AOP) is an uncommon anatomic variant that provides arterial supply to the paramedian region of the thalami and bilaterally to the rostral part of the midbrain; it is a solitary arterial trunk that branches from a proximal segment of the posterior cerebral artery (PCA). Although AOP infarction results in a characteristic pattern of ischemia, namely bilateral paramedian thalamic infarct with or without midbrain involvement, it may cause diagnostic difficulties due to the variety of its clinical presentations and wide differentials, as well as its small diameter and the difficulty of obtaining visualization through diagnostic imaging. Early neuroimaging of AOP infarction and correct diagnosis are mandatory for early initiation of the appropriate treatment and better patient outcomes. This study discusses the imaging patterns and imaging differentials of AOP infarction and its clinical presentation. A 55-year-old man presented to the emergency department unconscious with Glasgow Coma Scale score of 4. Pupillary light reflex on both eyes was poorly reactive with dilatated right pupil. The patient flexed his arm and extended his leg on painful stimulus. Laboratory tests and electrocardiogram were unremarkable. Emergency cerebral CT scan and transcranial Doppler ultrasound were normal. He gradually regained consciousness with residual somnolence, ptosis, and vertical gaze palsy. Second CT scan showed bilateral paramedian thalamic areas of hypodensity, CT angiography (CTA) was unremarkable. MRI showed bilateral high-signal intensity on paramedian thalami fast spin echo T2, FLAIR, and diffusion-weighted sequences, low signal on apparent diffusion coefficient sequence. MR angiography (MRA) revealed an abnormal tiny vessel arising from the P1 segment of the left posterior cerebral artery. Imaging findings were consistent with AOP infarction. Aspirin was started, 4 hours after admission the patient regained consciousness, and gradually improved on the following days till he was discharged on the 15th day, with mild neurologic deficit. AOP must be considered whenever paramedian thalamic infarction is noted in neuroimaging. The difficulty in visualizing the AOP using diagnostic imaging is due to its small diameter, leading to the limited abilities of MRA and CTA to diagnose AOP infarction. An absence of evidence of AOP infarction in MRA or even CTA does not exclude its diagnosis. Good knowledge of the imaging characteristics of AOP infarction will help in early diagnosis and the achievement of good patient outcomes., (© 2020 The Authors. Published by Elsevier Inc. on behalf of University of Washington.)