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INTRODUCTION The artery of Percheron (AOP) is a rare anatomical variant in which bilateral paramedian thalami are supplied by a single vascular branch arising from the P1 segment of the posterior cerebral artery. We present a case of AOP occlusion presenting as loss of consciousness and summarize the literature in Chinese to find the clinical characteristics. CASE REPORT An 83-year-old woman was found unconscious for 1 day at home and was sent to the hospital the next day. Cerebral magnetic resonance imaging on day 1 of the patient showed a recent bilateral paramedian thalamic infarction. Simultaneously, magnetic resonance angiography found evident artery stenosis of the right P1 segment of the posterior cerebral artery, suggesting that the patient was diagnosed with AOP occlusion. Since the patient has missed the best time for thrombolytic therapy, anticoagulant therapy was given immediately; as the patient was then found to have pulmonary infections, antibiotic therapy was also initiated. The neurological status of this patient improved very slow. In about 2 weeks, the patient becomes more conscious but still could not speak or move. CONCLUSION Our report suggests that unusual mood disorder and language disorder of aged patients might indicate the AOP occlusion, and cerebral imaging of magnetic resonance imaging (better with magnetic resonance angiography) should be performed to establish the diagnosis of AOP occlusion. The fast and accurate diagnosis of stroke because of AOP occlusion could best benefit the patients.

RESUMEN El tálamo posee una irrigación vascular compleja, llena de variantes anatómicas de relevancia para los estudiantes de la medicina. La presencia y el infarto producido por la oclusión de la arteria de Percherón es caracterizado por un cuadro clínico raro, poco conocido por los médicos del Servicio de Urgencias. Generalmente está asociado a la triada de alteración de la consciencia, parálisis de la mirada vertical y alteraciones de la memoria. Presentamos el caso de un varón de 54 años que se presenta con alteración del sensorio, somnolencia y alteraciones de la memoria, en el que no se pudo realizar terapia adecuada debido al desconocimiento de dicha entidad. ABSTRACT The thalamus has a complex vascular supply, full of anatomical variants of relevance to medical students. The presence of the Percheron artery is one of these anatomical variants, and the infarction produced by its occlusion is characterized by a rare clinical picture, little known by doctors in the Emergency Department. It is generally associated with the triad of impaired consciousness, vertical gaze palsy, and memory disturbance. We present the case of a 54-year-old man who presented with altered sensorium, drowsiness and memory alterations, in whom adequate therapy could not be carried out due to ignorance of this entity.

The circle of Willis is a very important vascular mechanism of protecting against cerebral ischemia, especially when circulation within the main arteries irrigating the brain is somehow impeded. As result of congenital malformation arising early in embryonic development, the fetal-type posterior circle of Willis remains as such during the rest of one's life. Consequently, the posterior cerebral artery (PCA) becomes a branch of the internal carotid artery (ICA), rather than of the basilar artery (BA). Furthermore, the rest of collateral circulation, between the anterior and the posterior regions of the brain, is also negatively affected (e.g., leptomeningeal vessels). The anatomical variant represented by the artery of Percheron (AOP) has its origin on one of the PCAs, supplying singlehandedly both paramedian areas of the thalamus (right and left) and posterior regions of the midbrain. In the present study, we report a case of bilateral thalamic infarction with midbrain involvement, where the correct diagnosis was made retrospectively using computed tomography (CT) scan, magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI) and three-dimensional time-of-flight magnetic resonance angiography (3D TOF MRA).

The artery of Percheron (AOP) represents a rare anatomic variant of the posterior circulation. It is a solitary trunk that provides bilateral arterial supply to the rostral midbrain and paramedian thalamus. AOP infarction presentation varies, most often presents with altered mental status, memory impairment, and supranuclear vertical gaze palsy. Diagnosis of the AOP infarct is most often missed in the initial CT scan. A majority of these diagnoses are made outside the window of thrombolytic treatment for ischemic stroke. We report a case of a 67-year old male with a history of well-managed diabetes mellitus type 2 and hypertension, presented in the ER sudden onset severe drowsiness. On a physical exam, we found left pupil dilation and left eye deviation. Initial CT scan showed no pathological changes. The diagnosis was made on the third day of hospitalization via an MRI. Our case highlights the unusual presentation and that an absence of evidence of AOP infarction in CT scan does not exclude its diagnosis. The artery of the Percheron infarct requires a comprehensive clinical and radiological examination.

Radiological imaging is important in the diagnosis of the artery of Percheron (AOP) infarction. This study aimed to discuss the magnetic resonance imaging (MRI) findings of this abnormal variant of arterial supply. Patients who presented to our hospital with stroke symptoms between 2010 and 2019 and underwent brain MRI were evaluated retrospectively. Eleven patients with AOP infarction were included in the study. The mean age of the patients was 67.4 ± 9.6 years. Seven (63.6%) of the patients were male and four (36.4%) were female. Accompanying diseases were hypertension in eight patients (72.7%) and coronary artery disease in five (45.4%). In eight patients (72.3%), the infarction of AOP extended under the third ventricle wall, and 90.9% of the patients had an asymmetrical radiographic pattern of ischemic damage. With the widespread use of endovascular stroke treatment, it has become critical to establish a rapid and accurate diagnosis of stroke to achieve recovery without sequela. Therefore, although the infarction of AOP is rare, a rapid and accurate diagnosis is important due to possible morbidity and mortality and can be undertaken using MRI.

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. In this study, we discuss imaging the patterns of AOP infarction and its differentials and clinical presentation.

Introduction: Pseudobulbar palsy (PBP) is characterized by supranuclear lesions in the corticobulbar pathway. Neoplasia, inflammatory, demyelinating, and stroke are possible etiologies of this disorder. Case report: We report an elderly female who presented with dysarthria. She was dysarthric with a hypernasal voice, no apraxia or aphasia was observed. Tongue movements were slow with limited amplitude. Her soft palate dropped bilaterally; gag reflex was present. Also, she reported swallowing difficulty and choking with her saliva. Bilateral vertical and horizontal gaze were intact to either voluntary or oculocephalic movements. A cranial CT scan was suggestive of artery of Percheron (AOP) infarction. Brain magnetic resonance imaging showed hypersignal on diffusion-weighted and T2-weighted images and hyposignal on apparent diffusion coefficient in both thalami. CT angiography scan revealed an AOP originating from the left posterior cerebral artery. The swallowing study with a videofluoroscopic demonstrated oral and pharyngeal phases with severe dysfunction. Conclusion: To the authors’ knowledge, there are two cases of individuals with artery of Percheron infarction who devel- oped PBP associated with other clinical syndromes. Still, isolated PBP following infarction of Percheron’s artery was not reported. We hypothesized that the PBP may have occurred because of the existence of vascular territory variations in the perforating arteries that arise from the AOP. Keywords: Pseudobulbar palsy; thalamus; infarction.

Vertical one-and-a-half syndrome (VOHS) is an uncommon presentation resulting from a unilateral thalamomesencephalic stroke with involvement of the rostral interstitial nucleus of the medial longitudinal fasciculus and posterior commissure. The artery of Percheron (aPe) is a branch of the posterior cerebral artery (PCA) and it is a variant that arises as a solitary trunk supplying both medial thalami and upper midbrain. A 78-year-old female patient, presented at the hospital emergency with approximately 12 hours of sudden onset of diplopia, associated with dizziness. Neurological exam revealed torsional nystagmus associated with bilateral upgaze palsy with limitation of infraduction on the left. We describe a rare case of VOHS associated with ischemic alterations at the MRI suggesting an aPe impairment. The conjugate gaze control lies anatomically at the midbrain at the central nervous system (CNS). This report describes a rare type of VOHS and brings a new insight on a possible aPe topography possibly causing this clinical presentation.

The artery of Percheron is a small vessel whose occlusion causes bilateral paramedian thalamic and rostral midbrain stroke. COVID-19 is an independent risk factor for acute small vessel ischemic stroke. We presented the case of a young adult patient with infarction in the artery of Percheron territory as a presenting feature of COVID-19. Artery of Percheron infarction is a neurodiagnostic challenge in emergency during COVID-19 pandemic.

Bilateral thalamic infarction is a rare entity (it occurs in 0.6% of ischemic strokes) and can be confused with other vascular etiologies such as basilar syndrome and deep cerebral venous thrombosis, as well as neoplasms, infections, or toxins. It is typically characterized by the triad of altered mental status, vertical gaze paralysis, and memory impairment, although their symptoms can be highly variable. We describe the case of a young man who came to the emergency department presenting diplopia, speech alteration, and decreased level of consciousness with frequent fluctuations. Baseline computerized tomography was normal, and because of the clinical findings, thrombolysis was performed. Subsequently made magnetic resonance showed a bilateral acute thalamic infarction caused by an obstruction of the Percheron artery. Although Percheron syndrome has been previously described in medical journals, our case is an unusual case in which we could perform an acute intravenous thrombolytic treatment. Besides, it is important for emergency physicians to enclose the Percheron syndrome in the differential diagnosis of coma in young people so that emergent treatments such as thrombolysis can be employed.

An 80-year-old woman with history of hypertension presented to the emergency department following a fall. Her mental status quickly deteriorated and became obtunded. She was stuporous, and unresponsive to verbal stimuli. She had minimally reactive pupils and was moving extremities to painful stimuli. An MRI scan was performed following an unrevealing CT brain.

Management of pituitary apoplexy is multimodal. The surgical intervention followed by endocrinological management is the standard of care. Various vascular complications have been described in the literature after pituitary adenoma surgery. Artery of Percheron (AOP) infract is a rare finding. Few cases were reported in the English literature after the endoscopic approach for pituitary adenoma. We present a 55-year-old lady presented with sudden-onset headache followed by vision loss. She was evaluated with imaging and diagnosed pituitary adenoma with apoplexy. She underwent an endoscopic transnasal approach and decompression of the tumor. In the postoperative period, she developed bilateral ptosis with altered sensorium. Imaging showed infarction of bilateral paramedian thalamus and rostral midbrain, suggestive of AOP infarct. Gradually, the patient improved, and at 3 months of follow-up, she was conscious and obeying with partial improvement of ptosis.

Arteriovenous malformation (AVM) fed by the artery of Percheron (AOP) is extremely rare, with only one case described in the literature to date. We herein present a case of a 43-year-old female with hemorrhagic thalamic AVM mainly supplied by the AOP, who subsequently underwent conservative management and recovered well except for mild right hemiparesis. This case highlights that the AOP is a rarely recognized but clinically significant entity and should be identified when dealing with AOP-associated neurovascular disorder as described.

Artery of Percheron (AOP) is an abnormal variant of the arterial supply of the thalamus. AOP occlusion can lead to bilateral thalamic and rostral midbrain infarct presenting as memory loss, fluctuating levels of consciousness, and altered mental status. A 43-year-old woman with a history of antiphospholipid syndrome (APS), managed on dabigatran, presented with acute confusion and drowsiness. She had slurred and slowed speech, disorientation in time and place, left-sided facial droop, decreased power of the left side (4/5), and was unable to walk due to generalized weakness. Labs showed a prolonged prothrombin time and activated partial thromboplastin time, positive lupus anticoagulant, anti-cardiolipin, beta-2 glycoprotein, anti-nuclear and anti-dsDNA antibodies. Contrast-enhanced CT perfusion showed ischemic changes in the bilateral thalami, suggesting infarct along the AOP territory. AOP infarcts are scarce and the presenting complaints are unusual of cerebrovascular accidents. It requires a high index of suspicion to detect. There are no other reports in the literature of patients with APS presenting with an AOP infarct. Considering the lack of evidence, we recommend against the use of newer oral anticoagulants (NOACs) for secondary prevention of vascular events in patients with triple-positive APS.

Artery of Percheron (AOP) is a rare anatomical variant in which a single perforating artery arising from the P1 segment of the posterior cerebral artery supplies paramedian thalami and rostral midbrain. The occlusion of AOP produces bilateral thalamic ischemia and may be a rare complication in relation to an extended endoscopic endonasal approach. We report the case of a patient who developed AOP damage during endoscopic endonasal surgery (EES); to our knowledge, this complication has been previously reported only in one case, in relation to a second surgery. We also review the anatomical variants in thalamic vascularization and the factors that may be involved in this complication. A 52-year-old female underwent an extended endoscopic endonasal approach with intraoperative neurophysiological monitoring. In the postoperative period, she presented with a decreased level of consciousness and bilateral mydriasis. Magnetic resonance imaging showed rostral midbrain and paramedian thalami ischemia congruent with AOP infarction. AOP infarction may be associated with extended EES when treating lesions with retrosellar extension. Every effort should be made to preserve the small perforating arteries. Intraoperative neurophysiological monitoring of the motor and sensory pathways may not detect damage to the AOP.

Introduction: Extensive tattooing co-occurring with other lifestyle risk factors (cannabis and tobacco smoking) represents unhealthy behavior trends in some groups of teenagers and young adults. Case report: This case study synthetically presents a 2 years evolution of a 37-year-old man, with 20-year history of progressive and regular cannabis exposure and tobacco smoking. In January 2017 he suffered a severe paramedian thalamo-mesencephalic embolic stroke of undetermined source and coma, preceded by laborious tattooing maneuvers. Uncommon anatomical variants of cerebral circulation (a right-sided fetal type posterior cerebral artery and an inferred artery of Percheron) were detected. The rehabilitation program and abstinence from smoking tobacco and marijuana led to significant neurologic improvement, with no vascular recurrence until September 2018, when he suddenly suffered from a transient ischemic attack in the vertebrobasilar arterial territory. Recurrence of the cerebral ischemic event during a disciplined program of abstinence imposed clinical re-examination, blood analysis, peripheral venous Doppler, 24-hours ECG Holter. Finally transesophageal echocardiography has revealed the embolic source, and detected patent foramen ovale (PFO) with minimal shunt. He was informed that he should undergo PFO closure. His first option was for conservatory management, using a dual antiplatelet medication (75 mg clopidogrelum, 75 mg aspirin). In October 2019 his cardiac congenital malformation was successfully operated. Case closed. Discussion: Stroke was triggered by extensive tattooing maneuvers that induced bleeding, local and systemic inflammatory reactions, in a young person predisposed to cerebral infarction. The complex physiopathological picture included a "puzzle" of harmful xenobiotics (contained in cannabis and tobacco smoke, respectively in tattooing ink), overlapping with the unknown pre-existing asymptomatic cardiac malformation, and neurovascular uncommon anatomic variant. Prevention of stroke in young adults is the primary treatment strategy, as Hippocratic Oath postulates: "I will prevent disease whenever I can, for prevention is preferable to cure". Healthcare professionals must educate people and promote prophylactic interventions against modifiable risk factors. Secondary prevention of recurrent strokes must be directed towards etiology, and mechanisms responsible for the incident, and a rigorous management of additional risk factors.

The artery of Percheron (AOP) is a single dominant thalamo-perforating artery that supplies bilaterally the medial thalami with variable contribution to the rostral midbrain. Occlusion of the AOP causes indeed variable and unspecific clinical symptoms due to this complex anatomy, and very often this diagnosis is delayed with the impossibility of recurring to intravenous thrombolysis (rTPA). Here, we report a case of AOP stroke that received a prompt diagnosis and therapy, owing to the availability of MR brain scan, showing a DWI/FLAIR mismatch typical of hyperacute infarctions. This case points out the importance of a high level of suspicion of AOP stroke, together with the correct implementation of imaging studies.

Objective:Survivors of patients with artery of Percheron infarction (API) often have a prolonged and disabling form of cognitive impairment that remains insufficiently characterized. We aimed to examine the clinical and cognitive features of API in the short and long term after stroke.Methods:We reviewed 6400 patients with a first-ever stroke included in the Stroke Registry between 2011 and 2021. The diagnosis of API was based on clinical diagnosis and imaging confirmation. All patients underwent neuropsychological assessment at hospital stay and 1 year after stroke. A z-score of each patients’ cognitive test point was calculated, and a z-score inferior to 2 was considered as pathological.Results:Of the 10 patients enrolled, all had cognitive impairment, consciousness, and behavioral disorders at stroke onset. Six patients had pure bilateral thalamic involvement while four had bilateral thalamic and rostral midbrain involvement. At 12 months, 50% of patients had global mental state scores 2 SD below the population mean (z-score mean ± SD, −2.17 ± 0.4). Most of the prefrontal cortex cognitive processes including executive functions such as planning and cognitive control (z-score mean ± SD, −3.92 ± 0.3), processing speed (−4.42 ± 0.5), working memory (−3.97 ± 0.3) were severely impaired at stroke onset. Especially in patients with thalamic and rostral midbrain involvement, deficiencies in executive function (z-score mean ± SD, −2.60 ± 0.4), processing speed (−2.22 ± 0.5), working (−3.76 ± 0.4), and episodic memory (−2.23 ± 0.3) continued 12 months after stroke.Conclusions:The occlusion of the artery of Percheron results in severe behavioral and cognitive disorders in the short and long term after stroke.

Acute cerebral infarction due to occlusion of the artery of Percheron (AOP) is rare and poses a diagnostic challenge due to unspecific clinical symptoms. A prompt diagnosis and treatment is vital due to a potentially very serious outcome. Here we represent a healthy young woman who developed sudden headache and loss of consciousness. At admission she was unconscious with GCS of 4, pupils were unevenly dilated and poorly reactive and the plantar reflex was upward bilaterally. She had seizure like movements in all limbs. CT of brain and CT angiography were normal but acute MRI showed bilateral paramedian thalamic diffusion restriction. The patient was treated with i.v. thrombolysis (tPA) 70 minutes after hospital arrival and recovered fully.

The artery of Percheron (AoP) is a rare anatomic variant, where the paramedian thalami and the rostral midbrain are supplied by an artery emerging from the P1 segment of the posterior cerebral artery. Ischaemic infarction of the artery of Percheron occurs rarely, accounting for 0.1 to 2% of all ischaemic strokes. AoP occlusion can lead to an infarction of the paramedian thalami and mesencephalon, resulting in a triad of clinical features; namely, altered mental status, vertical gaze palsy and memory impairment. A larger mesencephalon infarction can also feature oculomotor disturbances. We describe here the case of an 88-year-old patient, presenting with this triad of features. LEARNING POINTS Neurological events such as ischaemic strokes can have a wide clinical presentation. Artery of Percheron infarction is characterized by memory impairment, vertical gaze palsy and altered mental status. Pattern recognition is fundamental for early diagnosis and optimal care.

A 90-year-old male patient presented with excessive somnolence, right-sided weakness, and left facial droop. CT and MRI scans of the head, taken several days after initial head CT proved to be non-revealing, demonstrated a bilateral thalamic stroke, a rare phenomenon. The infarct arose in the territory of the artery of Percheron, an anatomic variant in which a single artery supplies both sides of the thalamus and midbrain. When this artery becomes occluded, it results in severely dysregulated consciousness and alertness. This type of stroke proved challenging for the medical team, due to poor resolution of initial imaging, as well as the therapy teams, due to the constant need for sleep. This case report outlines how barriers in diagnosis and management make knowledge of the artery of Percheron and its occlusion crucial to patient care and recovery.

This chapter includes (1) P1 aplasia and hypoplasia of the PCA (Fetal-type PCA), (2) Extremely long PCoA and P1 segment of the PCA, (3) Duplicate origin of the PCoA, (4) PCA branch arising from the PCoA, (5) Hyperplastic AChA (Accessory PCA, Replaced PCA), (6) Duplication of the PCA, (7) Duplicate origin of the PCA, (8) Fenestration of the PCA, (9) Early bifurcation of the PCA, (10) Artery of Percheron, and (11) Infundibular dilatation of the PCoA, AChA and hypoplastic P1 segment of the PCA. There are 21 figures and 2 illustrations.

Artery of Percheron occlusion is a rare cause of ischaemic stroke characterized by bilateral thalamus infarction. Presentation is varied and non-specific, with the most frequent manifestations being altered level of consciousness, hypersomnolence or altered oculomotor movements. We describe the case of a 37-year-old man hospitalized for hypersomnia and hypomnesia with 3 days of evolution, who was diagnosed with a bilateral thalamus stroke due to artery of Percheron occlusion. LEARNING POINTS Stroke is frequently encountered but can present a diagnostic challenge when presentation is non-specific or a lesion is not identified. Artery of Percheron stenosis has a varied and often non-specific presentation, which can lead to delayed diagnosis and treatment of these patients. It is important that doctors recognize this entity for timely diagnosis and treatment, and for the best prognosis.

Midbrain infarction rarely causes partial fascicular oculomotor palsy, which is characterised by bilateral midriasis and loss of vertical gaze movements. We describe a patient with acute ischemic infarcts involving both uppermost part of the midbrain, presenting with marked vertical gaze palsy and mydriasis bilaterally as the only neurological abnormality. These features are suggestive of partial fascicular oculomotor palsies involving the pupil, inferior rectus, superior rectus, inferior oblique muscles and sparing medial rectus, levator palpebrae muscles. These neuro-ophthalmological and radiological findings in our case support the model that the fibers to medial rectus and levator palpebrae muscles might be located in the more caudal portion of the oculomotor fascicles.

A 54-year-old woman presented to the emergency department with fluctuating consciousness without localising signs and non-specific neurology. Urgent computed tomography (CT) was unremarkable and differentials of opioid overdose or post-ictal state were considered. Magnetic resonance imaging of the brain demonstrated an artery of Percheron (AOP) infarct; resulting from occlusion of an uncommon anatomical variant in the thalamic and midbrain circulation. This should be considered in patients presenting with fluctuating consciousness and normal CT.

Bilateral thalamic infarctions are uncommon and often lead to more severe and long-lasting symptoms than unilateral thalamic infarctions. This article describes a patient with bilateral thalamic infarction caused by occlusion in the artery of Percheron, an anatomic variant thought to be present in 4% to 12% of the population.

Artery of Percheron is a rare anatomical variant of thalamic vascular supply. Stroke involving this vasculature is an uncommon event. Occlusion of this vessel produces a peculiar pattern in the form of bilateral thalamic infarcts with or without midbrain infarction. This results in variable clinical features ranging from somnolence or altered sensorium to coma in affected individuals, accompanied by characteristic neurological manifestations. Diagnosis of artery of Percheron infarction at the initial presentation may be difficult as it is infrequent and early neuroimaging studies may be negative. Here we report a patient, a case of AOP infarct whose MRI brain and clinical picture demonstrated the characteristic features. Keywords: Artery of Percheron, Ischemic stroke, Thalamus, Magnetic resonance Imaging.

The bithalamic ischemic stroke secondary to percheron artery occlusion occupies a small place in the large ischemic stroke family, but its clinical polymorphism arouses patrician curiosity. We thus report 3 observations that explain the richness of this affection.

In this review, our intension is to present imaging features of several categories of uncommon cases of brain infarctions including infarctions associated with neurovascular variants, infarctions along small arterial territories, and brainstem stroke syndromes. Infarctions associated with neurovascular variants include azygos anterior cerebral artery territory infarction and artery of Percheron infarction. In the second group, we discuss anterior choroidal artery infarction and artery of Heubner infarction. The third group highlights brainstem stroke syndromes, including Claude and Benedikt syndromes due to midbrain infarction; Foville, Marie Foix, and locked-in syndromes due to pontine infarction; and Dejerine (medial medullary), bilateral medial medullary, and Wallenberg (lateral medullary) syndromes.