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The artery of Percheron is a rare anatomic variation in the brain vascularization, in which a single arterial trunk arises from the posterior cerebral artery to supply both sides of brain structures, i.e., the thalamus and midbrain. Occlusion of this uncommon vessel results in a characteristic pattern of bilateral paramedian thalamic infarcts with or without mesencephalic infarctions. We report the case of a Caucasian woman who completely recovers after transient coma due to Percheron artery infarction.

Artery of Percheron (AOP) is a rare anatomical variant, which supplies bilateral paramedian thalami and the rostral mesencephalon via a single dominant thalamic perforating artery arising from the P1 segment of a posterior cerebral artery. AOP infarcts can present with a plethora of neurological symptoms: altered mental status, memory impairment, hypersomnolence, coma, aphasia, and vertical gaze palsy. Given the lack of classic stroke signs, majority of AOP infarcts are not diagnosed in the emergency setting. Timely diagnosis of an acute bilateral thalamic infarct can be challenging, and this case report highlights the uncommon neurological presentation of AOP infarction. The therapeutic time window to administer IV tPA can be missed due to this delay in diagnosis, resulting in poor clinical outcomes. To initiate appropriate acute ischemic stroke management, we propose a comprehensive radiological evaluation in the emergency room for patients with a high suspicion of an AOP infarction.

Bithalamic infarction resulting from occlusion of the artery of Percheron after cervical spine surgery is a rare pathological entity. Diagnosis and early detection are challenging. Prompt management may help to improve the outcome. We present a case of a 39-year-old male patient, smoker, diagnosed with multiple cervical disc herniations, who underwent Anterior Cervical Discectomy and Fusion (ACDF) for C3-C4, C4-C5, and C5-C6. During the 2-hour and 50-minute surgery, the patient was lying supine with his neck hyperextended. The intraoperative procedure was uneventful. During surgery, blood pressure ranged around 110 mmHg∖50 mmHg. At the end of surgery, the patient’s recovery from general anesthesia was normal with no delaying or complication; on next the day, patient developed a sudden loss of consciousness. Urgent brain computed tomography (CT) was normal; two days later, follow-up CT and CT Angiography (CTA) revealed bilateral thalamic infarction with right vertebral artery occlusion from its origin. Intraoperative surgical manipulation, hypotensive anesthesia, and prolonged neck hyperextension might have contributed to stroke in this patient. ACDF carries a potential risk for posterior circulation stroke. Artery of Percheron infarction should be considered in the differential diagnosis of patients developing a sudden loss of consciousness after ACDF. Vertebral artery thrombosis should be taken into account as an important possible cause of embolism.

Pediatric ischemic stroke is a rare and devastating disease. A patient presenting with acute neurological deficit should raise suspicion of a possible stroke. However, stroke “mimics” account for a majority of suspected stroke cases in childhood. We present three cases of pediatric acute is-chemic stroke, two of which are arterial, and one caused by thrombosis of venous sinuses. In the first case, we present a 16-year old male patient was admitted to our hospital due to a rare Artery of Percheron occlusion. The second case represents a 17-year old female patient with thrombosis of multiple cerebral venous sinuses, venous infarctions and secondary hemorrhages. As the third case, we present 6-year old male patient with a herpes simplex infec-tion and a vertebrobasilar stroke. All three patients had experienced an altered mental status and other nonspecific symptoms. Due to its rarity, diverse clinical presenta-tion, and lack of randomized control trials regarding treatment, ischemic stroke poses a great challenge to pediatricians.

This is an elderly patient who was found unconscious at home. CT of the head without contrast was unremarkable, while CT angiography of the head and neck revealed a subocclusive thrombus on the precommunicating (P1) segment of the left posterior cerebral artery (PCA). MRI brain revealed bilateral regions of diffusion restriction in the paramedian thalami and bilateral medial mesencephalon. Initial angiography confirmed the presence of a subocclusive thrombus in the P1 segment of the left PCA. Thrombectomy was performed achieving recanalisation of the left PCA and reperfusion of bilateral thalami via a visualised artery of Percheron. Postoperatively, the patient was kept on a daily dose of 325 mg of aspirin. The patient did not improve neurologically. A follow-up MRI brain showed diffusion restriction in the left occipital lobe and petechial haemorrhages in the bilateral thalami. The family eventually opted for palliative measures, and the patient expired on day 14 of admission due to acute respiratory failure from palliative extubating.

The artery of Percheron is a rare anatomical variation that supplies thalamus and the midbrain. A stroke in this area is a rare event. The presentation varies widely, with some bizarre disturbances, like transient episodic loss of consciousness similar to coma, somnolence, cognition and memory impairment and psychosis. We report a case of a patient who presented at the emergency department with a sudden change of consciousness. During the observation, she oscillated reactive state of consciousness with obnubilation similar to coma. The first exams were normal, which include a cranial CT of the brain, and so the patient was kept under observation. The final diagnosis was only possible 24 hours later with cranial CT where an ischaemic lesion on the Percheron territory was identified. This case highlights an unusual clinic and a difficult neuroimaging stroke diagnosis of a rare condition, that is unknown to most of the physicians.

An occlusion of the artery of Percheron (AOP) is a rare clinical condition that remains a diagnostic challenge for physicians given its variable presentation. This infarction is a result of an anatomical variant of a single vessel arising from the posterior cerebral artery. Occlusion of the AOP results in variable levels of alteration of consciousness, vertical gaze palsy, and memory impairment. Unfortunately, due to this variable presentation these strokes are often missed. We report a case of a 71 year-old-female who presented with sudden onset of unresponsiveness who was subsequently diagnosed with bilateral thalamic infarction with midbrain involvement secondary to AOP occlusion. Delayed diagnosis can result in poor neurologic outcomes as demonstrated in this case making it imperative to bring further awareness to this clinical syndrome.

We present a unique case of a patient who suffered two rare events affecting the supranuclear control, first of the vertical and second of the horizontal eye movements. The first event involved bilateral thalamic infarcts that resulted in double depressor palsy. The second event occurred 1 year later and it involved supranuclear control of horizontal eye movements creating pursuit deficit. A 47-year-old male presented with complaints of diplopia upon awakening. He had atrial fibrillation, mitral valve regurgitation, aortic valve regurgitation, and a history of spleen infarction 1 year ago. His right eye was hypertrophic and right eye downgaze was limited unilaterally of equal degree in adduction and abduction. The patient was diagnosed with double depressor palsy of the right eye. Magnetic resonance imaging (MRI) of the brain showed an old infarction of the left thalamus, and diffusion MRI showed acute infarction of the right thalamus. The patient’s daily warfarin dose was 2 mg and it was increased to 5 mg with cilostazol 75 mg twice a day. Seven weeks later, the patient’s ocular movement revealed near normal muscle action, and subjectively, the patient was diplopia free. At follow-up 12 months later, the patient revisited the hospital because of sudden onset of blurred vision on right gaze. He was observed to have smooth pursuit deficit to the right side, and orthophoric position of the eyes in primary gaze. MRI of the brain showed an acute infarction in the right medial superior temporal area. The patient experienced very rare abnormal eyeball movements twice. This case highlights the importance of evaluating vertical movement of the eyes and vascular supplies when patients present with depressor deficit and supports the theory of a supranuclear function in patients who present with pursuit deficit.

Aim: The aim of this study is to analyze the incidence, etiology, symptoms, diagnostic process and treatment of bilateral thalamic infarct on the basis of our own experience. Case series: Five cases of bilateral paramedian thalamic stroke with different clinical manifestations are presented. In two patients the presence of artery of Percheron was detected. Comment: The bilateral thalamic infarct is an unusual and rare type of ischemic stroke. Due to the variety of symptoms, it may be difficult to diagnose without MR imaging. Symptoms may be transient, but frequently a persistent neurological deficit is observed. The thalamus is the “centre” for all impulses reaching the brain. It is involved in cognitive functions, emotional and motor responses. Therefore, impaired consciousness and behavioral changes are the main symptoms of thalamic stroke.

The artery of percheron is a rare vascular variant, occlusion of which is uncommon and associated with bilateral paramedian thalamic infarcts with or without mesencephalic infarctions. We report a case of a 50 year-old male patient with acute bilateral thalamic infarcts. Patient presented with history of sudden onset of altered sensorium with episodes of restlessness, agitation and loss of consciousness. Non-contrast CT scan of head was suggestive of bilateral paramedian thalamic infarcts.

The artery of Percheron (AOP) is a rare vascular variant in which a single dominant thalamoperforating artery arises from the P1 segment and bifurcates to supply both paramedian thalami. Occlusion of this uncommon vessel results in a characteristic pattern of bilateral paramedian thalamic infarcts with or without mesencephalic infarctions. We report a case of a 37-year-old man with acute bilateral thalamic infarcts. The scans revealed symmetric bilateral hyperintense paramedian thalamic lesions consistent with an acute ischemic event. The posterior circulation was patent including the tip of the basilar artery and both posterior cerebral arteries, making the case compatible with occlusion of the AOP. This type of infarct is associated with embolic phenomena, and further evaluation revealed a patent foramen ovale as the source of emboli in the cerebrovascular circulation. The occlusion of the AOP is a rare cause of coma in young patients, and early recognition of this rare disease entity may lead to more favorable outcomes.

The artery of Percheron is a single dominant vessel of posterior cerebral artery which supplies the thalamus bilaterally. It is a rare variant of arterial supply to the paramedian thalami. The classical triad of presentation of artery of Percheron occlusion is vertical gaze palsy, memory impairment, and alteration of mental status. Here we report a case of artery of Percheron occlusion where the patient presents with classic features of thalamic infarction associated with the midbrain involvement evidenced by the presence of bilateral hemiparesis. When compared to the typical thalamic infarction alone, the prognosis is worse when midbrain is also affected.

The thalamus and the mesencephalon have a complex blood supply. The artery of Percheron (AOP) is a rare anatomical variant. Occlusion of this artery may lead to bithalamic stroke with or without midbrain involvement. Given its broad spectrum of clinical features, AOP stroke is often misdiagnosed. Usually, it manifests with the triad of vertical gaze palsy, memory impairment, and coma. In this article, we report three cases of bilateral thalamic strokes whose clinical presentations were dominated by a sudden onset of hypersomnia. We also reviewed last 5 years’ publications related to the AOP strokes in males presenting sleepiness or equivalent terms as a delayed complication. The AOP stroke may present a diagnostic challenge for clinicians which should be considered in the differential diagnosis of hypersomnia.

The artery of Percheron (AOP) is a variant of the paramedian thalamic vasculature that supplies blood to the medial aspect of the thalamus and the rostral midbrain. The presentation of an infarct in this territory varies widely and is often characterized by nonspecific neurological deficits, with altered mental status, decreased level of consciousness, and memory impairment being among the most common. AOP infarcts are often missed on initial computed tomography (CT) scan, and additional imaging is usually not done due to low suspicion for stroke in most cases. There have been an increasing number of reports of AOP infarction, illustrating the diversity of clinical presentations and the challenge this presents to clinicians in the acute setting. Lacking the classic signs of stroke, many of these patients experience a delay in recognition and treatment, with the majority of diagnoses occurring outside the tissue plasminogen activator (tPA) window. This case highlights the unusual presentation and diagnostic difficulty of a patient with an AOP infarct, and serves as a reminder to include thalamic pathology in patients presenting with vague neurological symptoms and no obvious signs of stroke.

Improvements in techniques, contrast agents, and catheter design have significantly decreased angiography-related neurological deficits and complications. This article reports a case involving an angiographic total obliteration arteriovenous malformation (AVM) in a patient with an acute infarction in the artery of Percheron (AOP) distribution following angiography. Furthermore, imaging of an AOP acute infarction in cerebral angiography is presented.

Artery of Percheron (AOP) occlusion is a rare cause of ischemic stroke characterized by bilateral para-median thalamic infarcts. It usually presents with altered mental status, hyper-somnolence and ocular movement disorders. Here, we report a case of cardio-embolic AOP infarction in a 72-year-old man with sepsis and new-onset atrial fibrillation. Early diagnosis is challenging, but diffuse-weighted magnetic resonance imaging demonstrates the lesion in the acute setting. Anticoagulation therapy was started and patient’s mental status gradually improved.

Introduction The artery of Percheron is a rare anatomic variant supplying bilateral medial thalamic nuclei and a variable portion of the rostral part of midbrain. Case report A 48-year-old female with massive subarachnoid hemorrhage due to a ruptured aneurysm of the paramedian artery of Percheron presented to the emergency room. Because of significant risk of recurrent intracranial hemorrhage, it was decided to proceed with endovascular embolization of the aneurysm. The patient was ultimately sent to a rehabilitation center and her presenting neurologic deficits showed significant improvements in the weeks following endovascular embolization treatment. Discussion The paramedian artery of Percheron is a rare anatomic variant and subarachnoid hemorrhage due to aneurysm of this artery is exceedingly rare. This case underlines the importance of a correct evaluation of cerebral arterial anatomy in order to choose the best endovascular therapeutic approach, reduce complications, and optimize patient outcome.

A 59-yr-old woman presented with a sudden onset of headache with neck pain and stiffness, Hunt and Hess grade 2. Brain computed tomography (CT) showed subarachnoid hemorrhage, Fisher Grade 2. Intra-arterial digital subtraction angiography (IADSA) showed a basilar artery apex aneurysm, dome size 9 mm and neck 3 mm, leaning towards the right, and a dominant right artery of Percheron. Endovascular treatment and microsurgical clipping were both explained to the patient, but she decided to undergo microsurgery due to the durability of treatment. She underwent a right frontotemporal craniotomy and orbital osteotomy. We performed optic nerve decompression and intradural anterior clinoidectomy to enhance the exposure. Working through the carotid-oculomotor space, the posterior communicating artery was traced back to the posterior cerebral artery. The basilar artery was temporarily occluded for aneurysm dissection after burst suppression to protect the brain. The aneurysm was irregular, multilobulated, and projecting upward. The dominant thalamoperforate artery (artery of Percheron) was arising from the right P1, and densely adherent to the sac of the aneurysm. After dissection of the artery of Percheron away from the aneurysm, it was completely occluded by a side-curved titanium clip. The patient had right oculomotor nerve paresis and headache postoperatively, but at discharge 2 wk later the headache and paresis had completely resolved. The postoperative IADSA showed total occlusion of the aneurysm with patency of the artery of Percheron. This 3-dimensional video shows the technical nuances of microsurgical clipping of a ruptured basilar apex aneurysm and intraoperative dissection of the artery of Percheron. Informed consent was obtained from the patient prior to the surgery that included videotaping of the procedure and its distribution for educational purposes. All relevant patient identifiers have also been removed from the video and accompanying radiology slides.

The occlusion of the artery of Percheron (AOP) is a rare condition that causes bilateral thalamic ischemic stroke with or without midbrain involvement. It happens as a result of an anatomical variant of the diencephalic irrigation, in which the thalamic paramedian arteries arise from a common trunk from the posterior cerebral artery (PCA), which generates a clinical syndrome characterized by bilateral vertical gaze palsy, memory impairment and hypersomnia. In this case, we report a 62-year-old woman admitted to the emergency room with altered mental status, mainly somnolence. On physical examination, she was somnolent, apathetic and with no motor deficit. Magnetic resonance imaging (MRI) of the brain demonstrated bilateral thalamic hyperintensities and midbrain involvement in diffusion-weighted imaging (DWI) and T2 sequences, suggesting occlusion of the AOP. Bilateral thalamic infarction due to this anatomical variant is an entity with a low prevalence, and its diagnosis can be delayed because of the wide spectrum of clinical signs.

Bilateral thalamic infarcts are uncommon posterior circulation strokes. The artery of Percheron (AOP) is a rare anatomical variant involving a singular arterial supply to both thalami and occlusion leads to bilateral thalamic infarction.We report the case of a 71-year-old man who presented with decreased consciousness (fluctuating Glasgow Coma Scale score of 5-7). He had a background of atrial fibrillation and was anticoagulated with dabigatran, a novel oral anticoagulant. Computed tomography (CT) scan showed a mildly reduced attenuation in the region of the left thamalus.Subsequent diffusion-weighted magnetic resonance imaging (MRI) showed acute brainstem infarction, extending into the thalamus bilaterally, likely due to AOP occlusion. Bilateral thalamic infarcts due to AOP occlusion may not be recognised on initial CT scan and are more readily seen using diffusion-weighted MRI, which is the most beneficial imaging modality to aid in early diagnosis and treatment.

An 86-year-old woman was admitted with multiple episodes of transient loss of consciousness. She was initially treated for seizures, and stroke was not considered likely. MRI on the same day of admission showed acute bilateral medial thalamic infarcts in keeping with the Artery of Percheron (AOP) territory infarcts. Investigation for polycythaemia and thrombocytosis showed JAK2 positive myeloproliferative neoplasm. A diagnosis of AOP infarction is often missed or delayed because it is rare and presents with variable neurological symptoms. Initial imaging in the form of CT is often negative, and some report that initial MRI findings may also be normal. An awareness of a wide range of differential diagnoses alongside a multi-modality imaging approach is required to reach a diagnosis. Although there are several other case reports of AOP infarction in the literature, this is the first to present with transient symptoms initially mistaken for seizure activity.

Background Coma is not a common symptom of stroke. Case Report We present a patient with a stroke to the artery of Percheron, which infarcted the bilateral paramedian thalami and resulted in coma. Why Should an Emergency Physician Be Aware of This? Identifying strokes in comatose patients is important for therapeutic management. The bilateral thalami are involved in maintaining consciousness. The artery of Percheron is an anatomic variant in the posterior circulation whereby the bilateral paramedian thalami are perfused by it solely. This is an atypical stroke syndrome that emergency physicians need to be able to identify.

Rarely, both paramedian thalami receive arterial blood flow from a single unilateral vessel arising from the first segment of 1 posterior cerebral artery. This artery has received the name of artery of Percheron (AP). There is no consensus regarding the true prevalence of this anatomical variant. Bilateral paramedian thalamic infarcts are uncommon (0.1% to 2% of ischemic strokes). The main cause is the occlusion of the AP due to cardioembolism. Diffusion-weighted magnetic resonance imaging demonstrates the lesion in the acute setting.From September 2004 to October 2011, we identified 5 patients who had bilateral paramedian thalamic infarcts. We describe clinical findings and diagnostic imaging patterns observed in these cases and review the literature.Three men and 2 women with bilateral paramedian thalamic infarction probably due to occlusion of AP are described. Mean age at presentation was 58±24 years. Magnetic resonance imaging showed the lesion in all patients. Four patients presented loss of consciousness as initial symptom. Only 1 patient evidenced mesencephalic extension of the infarct on magnetic resonance imaging, although 4 presented abnormal ocular signs. No patients received intravenous thrombolisis because of delayed diagnosis. All patients were discharged home. A 90-year-old woman recovered completely and the other 4 subjects persisted with cognitive symptoms and gaze abnormalities.Clinical presentation and imaging patterns described in this group of patients were similar to published data. High level of suspicion based on clinical and imaging findings is essential for early diagnosis of this rare condition. None of our patients had an early diagnosis of acute ischemic stroke and received proper thrombolytic treatment.

Blood supply to the thalamus and brainstem have frequent anatomic variations. One of these is where all the perforators to the above areas arise from a single branch of the posterior cerebral artery commonly known as the artery of Percheron. Infarction involving this artery leading to bilateral thalamic and midbrain lesions is not uncommon, but can cause diagnostic difficulties due to the varying clinical presentations possible and the wide differentials. Early brain imaging and diagnosis is important for initiating appropriate treatment. In this case report, we discuss a patient who presented with an artery of Percheron related stroke affecting the mid brain and paramedian thalamic areas. We also discuss the differentials of presentations with similar symptoms.

INTRODUCTON: Bilateral thalamic infarcts are rare presentations of stroke. They are the result of a complex combination of risk factors and a predisposing vessel distribution. An Artery of Percheron is a rare anatomic variation in the brain vascularization seen in one third of population. It was described by French medical scientist Gerard Percheron in 1973. The artery of Percheron, characterized by a single arterial trunk that irrigates both paramedian thalamic regions, can be occluded as a result of thrombo embolic diseases leading to bilateral paramedian thalamic infarcts. The main symptoms are vertical gaze palsy (65%), memory impairment (58%), confusion (53%), and coma (42%). Clinical and image findings of this uncommon form of posterior circulation infarct are presented along with their anatomic and pathophysiologic correlates. CASE PRESENTATION: A 75yrs old right handed female, known diabetic and hypertensive presented with sudden loss of consiousness 6 hrs prior to admission. MRI Brain showed restricted diffusion involving bilateral thalamus and midbrain-Artery of percheron infarct and chronic lacunar infarcts.MR-AngiogramSubacute infarcts in bilateral thalamic region and periaqueductal region of midbrain. The posterior circulation was patent including the tip of the basilar artery and both posterior cerebral arteries, making the case compatible with occlusion of the artery of Percheron. CONCLUSION: Bilateral thalamic infarcts are unusual presentations of posterior circulation stroke. In patients presenting with loss of consciousness, neuropsychiatric involvement bilateral paramedian thalamic infarction, the possibility of artery of percheron infarct should be considered. In addition, periaqueductal grey matter of midbrain can also be involved.

Coronary angiography is the golden choice for coronary artery disease evaluation and management. However, as with any invasive procedures, there is a risk of complications. We are reporting a case of 69-year-old male with past medical history of cardiac bypass surgery, CHF, hypertension, and hyperlipidemia who was admitted to the hospital to evaluate his chest pain. He had treadmill stress test that showed ischemic induced exercise. Patient underwent coronary angiography that showed proximal complete occlusion of the RCA with a patent graft. At the end of the procedure, the patient did not wake up and remained minimally responsive. An urgent brain MRI was ordered and showed infarctions consistent with an artery of Percheron infarction. Later, patient has improved slowly and was discharged home. We briefly here discuss this rare complication including the risk factor, clinical presentation, and the management.

Background: Simultaneous bilateral thalamic infarctions are rare and in most cases associated with typical clinical pattern which, beside other things, include neuropsychological changes. Case report: We report a case of a 37- year-old woman with acute onset ofdiplopia from skew deviation, right-sided central facial nerve palsy, left hemihypesthesia, ataxia, with normal level of consciousness and without any neuropsychological disturbances except minor memory deficit. She was diagnosed with bilateral thalamic infarction due to the cardioembolisation via patent foramen ovale. Conclusion: In cases of bilateral thalamic infarction one can presume the existence of rare anatomic variant of thalamic perfusion commonly known as the artery of Percheron, single artery trunk that branches to irrigate both paramedian territories of thalamus. The cause of infarction can be cardioembolism trough the patent foramen ovale, especially in young adults. Our case represents a combination of two specific pathological conditions - patent foramen ovale and bilateral thalamic infarction. Clinical presentation in this case was unusual for the bithalamic paramedian infarction.

A 71-year-old Caucasian female patient presented with acute onset of visual disturbance, gait difficulties and fluctuation of consciousness. Her medical history included artery hypertension, previous cardiac valve replacement with mechanical prosthesis, in treatment with oral anticoagulant. An emergency CT scan resulted negative for acute lesions, haematological exams were normal, international normalised ratio (INR) was >2.5. The EKG revealed high-frequency atrial fibrillation, not previously known. At the neurological examination, the patient presented drowsiness, easily resolved by verbal stimulus, bilateral divergent diplopia, with eye movements possible only horizontally and severe postural instability with retropulsion. On the day after the onset of neurological symptoms, the patient underwent brain MRI without gadolinium. Axial fluid attenuation inversion recovery (FLAIR) sequences revealed diffuse cerebral vasculopathy in the bilateral white matter without evidence of acute …

A bilateral thalamic ischemic stroke is a rare clinical manifestation resulting mainly from cardioembolism or small vessel disease. The ischemic stroke affecting the thalamus bilaterally may lead to memory and executive dysfunction, dis o rientation, oculomotor and conjugated gaze disturbances, motor deficit, cerebellar symptoms, apathy, stupor, somnolence and a coma. There have only been a few descriptions of the neuropsychological condition prevalent in this group of patients. The aim of the study was to present a detailed neuropsychological manifestation and follow-up with systematic rehabilitation. We present a 57-year-old female patient suffering from a bilateral thalamic ischemic stroke due to cardiogenic embolism of the artery of Percheron. The presented case summarizes the dynamics of the changes in cognitive and executive functions in the patient over the course of six months from the onset. We conclude that all bilateral stroke patients should undergo a detailed neuropsychological assess ment, an early, intensive rehabilitation process and a full cardiac investigation to unearth the potential causes.

Background The artery of Percheron is a rare anatomic variant of arterial supply to the paramedian thalamus and rostral midbrain, and occlusion of the artery of Percheron results in bilateral paramedian thalamic infarcts with or without midbrain involvement. Acute artery of Percheron infarcts represent 0.1 to 2% of total ischemic stroke. However, of thalamic strokes, occlusion of artery of Percheron is the cause in 4 to 35% of cases. Early diagnosis of artery of Percheron infarction can be challenging because it is infrequent and early computed tomography or magnetic resonance imaging may be negative. Thus, it can be confused with other neurological conditions such as tumors and infections. Case presentation This is a retrospective case study of a 56-year-old white man admitted to Umeå University Hospital and diagnosed with an artery of Percheron infarction. Medical records and the neuroradiological database were reviewed, and the diagnosis was made based on typical symptoms and radiological findings of artery of Percheron infarction. We report the case of a 56-year-old man with a history of overconsumption of alcohol who was found in his home unconscious and hypothermic. He had a Reaction Level Scale-85 score of 4. He developed ventricular fibrillation on arrival at our emergency department, and cardiopulmonary resuscitation successfully restored sinus rhythm within an estimated 2 minutes of onset. He was then put on cardiopulmonary bypass for rewarming. The initial head computed tomography performed on admission was wrongly assessed as unremarkable. Bilateral ischemia in the paramedian thalamic nuclei and pons were first documented on a follow-up computed tomography on day 24 after hospitalization. He died on day 35 after hospitalization. Conclusions Artery of Percheron infarcts are rare. The radiological diagnosis can initially often be judged as normal and in combination with variability in the neurological symptoms it is a rather difficult condition to diagnose. For these reasons few clinicians have much experience with this type of infarct, which may delay diagnosis and initiation of appropriate treatment.

Objective We aimed to report a novel case of hyperacute computed tomography (CT) perfusion imaging abnormalities in artery of Percheron infarction. Methods We described a case of a 74-year-old man who presented acutely to the emergency room with witnessed sudden onset altered level of consciousness. Results Although initial hyperacute CT brain imaging was reported as normal, subsequent magnetic resonance imaging revealed bilateral paramedian thalamic infarction. A retrospective review of CT perfusion imaging revealed perfusion mismatch in the bilateral thalami, which was not recognized in the hyperacute setting. Conclusion Artery of Percheron occlusion is a well-described cause of bilateral paramedian thalamic infarction, but to date, we have not identified any reports of perfusion imaging abnormalities in the hyperacute setting. This case emphasizes the important role of perfusion imaging when clinical presentation is not typical for ischemic stroke, but is suspected, given an acute onset; its recognition may have led to the consideration of thrombolysis acutely in this case (stroke chameleon).

The artery of Percheron is a rare anatomical variant where a single thalamic perforating artery arises from the proximal posterior cerebral artery (P1 segment) between the basilar artery and the posterior communicating artery and supplies the rostral mesencephalon and both paramedian territories of the thalami. Almost one-third of human brains present this variant. Occlusion of the artery of Percheron mostly results in a bilateral medial thalamic infarction, which usually manifests with altered consciousness (including coma), vertical gaze paresis, and cognitive disturbance. The presentation is similar to the "top of the basilar syndrome", and early recognition should be prompted. We describe the case of a young female with this vessel variant who experienced a bilateral thalamic stroke. Magnetic resonance angiography demonstrated bilateral thalamic infarcts and a truncated artery of Percheron. Occlusion of the vessel was presumably due to embolism from a patent foramen ovale. Thrombolysis was performed, with incomplete symptom remission, cognitive impairment, and persistence of speech disorders. Early recognition and treatment of posterior circulation strokes is mandatory, and further investigation for underlying stroke etiologies is needed.

1. A 54-year-oldmale presents to the emergency department with altered mental status and lethargy after being found down by his family. He is ultimately intubated for airway protection, and is now in the ICU. A non-contrast head CT is performed (see Image 1). Occlusion of which of the following vessels could explain this patient’s clinical presentation and CT findings? A. Artery of Adamkiewicz B. Artery of Drummond C. Artery of Heubner D. Artery of Percheron E. Artery of Samson

Introduction/Objectives: The artery of Percheron (AOP) is a rare anatomic variation in the brain vascularization characterized by a single arterial trunk arising from the posterior cerebral artery (PCA) to supply both sides of the thalamus and midbrain. The incidence of AOP infarction is rare (varied from 0.1 to 2%) in all ischemic strokes. The aim of this report is to describe a rare case of stroke caused by occlusion of the AOP due to cardioembolism from a patent foramen ovale (PFO). Participants, Materials/Methods: A case report. Results: A 47-year-old man presented in our emergency department with sudden onset of vertigo, gait instability and rapid deterioration in consciousness. Initial brain computed tomography (CT) performed on admission was normal. Magnetic resonance imaging (MRI) showed ischemic lesions in bilateral thalami and mesencephalon. A magnetic resonance angiography (MRA) was performed and demonstrated an absent P1 segment of the right PCA, indicating type II variation of the artery of Percheron. The patient was admitted to the stroke unit where he was treated with acetylsalicylic acid and gradually regained consciousness. Upon hospital discharge, mild ataxia and vertical gaze palsy was present. In further evaluation of stroke etiology a patent foramen ovale (PFO) was confirmed. Conclusions: Occlusion of the AOP is uncommon which makes early diagnosis very challenging. A comprehensive radiologic examination, including MRI is necessary when severity of clinical features does not correlate with the standard imaging findings. Early diagnosis may lead to timely and adequate treatment and therefore more favorable outcomes.