willis circle

OBJECTIVES: Isolated vertigo induced by posterior circulation ischemia (PCIV) can further progress into posterior circulation infarction. This study aimed to explore the diagnostic values of three-dimensional pseudo-continuous arterial spin labeling (3D-PCASL) combined with territorial arterial spin labeling (t-ASL) and magnetic resonance angiography (MRA) in visualizing and evaluating PCIV, seeking improved diagnostic tools for clinical guidance. METHODS: 28 PCIVs (11 males, 17 females, aged from 55 to 83 years, mean age: 69...

Moyamoya disease (MMD) is characterized by idiopathic, progressive stenosis of the circle of Willis and the terminal portion of the internal carotid arteries with the development of prominent small collateral vessels and a characteristic moyamoya or puff-of-smoke radiographic appearance. The incidence and prevalence of MMD varies by region, age, and sex, with higher rates in Asian and East Asian populations compared to North American or European populations. There is a bimodal distribution of patients diagnosed with MMD...

Changes in cerebral blood flow are often associated with the initiation and development of different life-threatening medical conditions including aneurysm rupture and ischemic stroke. Nevertheless, it is not fully clear how haemodynamic changes in time across the Circle of Willis (CoW) are related with intracranial aneurysm (IA) growth. In this work, we introduced a novel reduced-order modelling strategy for the systematic quantification of longitudinal blood flow changes across the whole CoW in patients with stable and unstable/growing aneurysm...

Computational fluid dynamics (CFD) has been utilized to calculate hemodynamic parameters in anterior communicating artery aneurysm (AComA), which is located at a junction between left and right A1 and A2 segments. However, complete or half circle of Willis (CoW) models are used indiscriminately. This study aims to suggest recommendations for determining suitable CoW model. Five patient-specific CoW models with AComA were used, and each model was divided into complete, left-half, and right-half models. After validating the CFD using a flow experiment, the hemodynamic parameters and flow patterns in five AComAs were compared...

PURPOSE: The aim of this registry was to assess technical success, procedural safety and mid- to long-term follow-up results of the Silk Vista "Mama" (SVM) flow diverter (BALT, Montmorency, France) for the treatment of proximal intracranial aneurysms. METHODS: Between August 2020 and March 2022, data from nine Italian neurovascular centres were collected. Data included patients' clinical presentation, aneurysms' size, location and status, technical details, overall complications and mid- to long-term angiographic follow-up...

INTRODUCTION: An anatomical structure that resembles the circle of Willis, the circle of Trolard is generated in the basal cistern and travels around the midbrain in a roundabout manner, passing adjacent to the lateral side of the cerebral peduncle. RESEARCH QUESTION: The primary objective of this article is to provide neurosurgeons with a comprehensive understanding of Trolard's circle, emphasizing its anatomical features and clinical significance. MATERIAL AND METHODS: A comprehensive evaluation of the available literature pertaining to the venous circle of Trolard was conducted by conducting searches in the PubMed, Web of Science, and Scopus databases...

BACKGROUND AND PURPOSE: Balloon test occlusion (BTO) evaluates cerebral ischemic tolerance before internal carotid artery (ICA) sacrifice but carries risks like dissection and thrombosis. This study introduces a new approach using a patient-specific circle of Willis (COW) blood flow model, based on non-invasive quantitative MR angiography (qMRA) measurements, to predict the outcomes of BTO. METHODS: We developed individualized COW blood flow models for 43 patients undergoing BTO...

PURPOSE: To evaluate the phenomenological significance of cerebral blood pulsatility imaging in aging research. METHODS: N = 38 subjects from 20 to 72 years of age (24 females) were imaged with ultrafast MRI with a sampling rate of 100 ms and simultaneous acquisition of pulse oximetry data. Of these, 28 subjects had acceptable MRI and pulse data, with 16 subjects between 20 and 28 years of age, and 12 subjects between 61 and 72 years of age...

INTRODUCTION: Traditional large craniotomies have been the standard for aneurysm surgery. However, minimally invasive "keyhole" approaches have gained popularity for aneurysm clipping in recent years. This study focuses on Supra-Orbital Keyhole Approach (SOKHA),its use in clipping of aneurysms of the anterior Circle of Willis. Here we share the experiences of a tertiary care center regarding aneurysm clipping using SOKHA. MATERIALS AND METHODS: We retrospectively reviewed 166 cases involving aneurysm clipping, with 62 patients undergoing SOKHA and 104 patients undergoing the pterional approach...

The cerebral arteries, specifically the anterior cerebral artery (ACA) and posterior cerebral artery (PCA), work together with the smaller calibre arteries to provide effective communication between the anterior and posterior circuits of the brain via the circle of Willis (CoW). Morphologic variations of the cerebral arteries and the CoW may alter blood flow to the brain, resulting in intracranial vascular disorders associated with stroke, and aneurysms. This study aimed to document the morphology of the cerebral arteries and the CoW in the South African population...

Vascular occlusive events are notable adverse effects of tyrosine kinase inhibitors (TKIs), which are promising treatments for chronic myeloid leukemia (CML). We herein report the case of a patient with CML who developed cerebrovascular occlusion of the circle of Willis during TKI treatment. Our patient did not meet the diagnostic criteria for moyamoya disease due to the insignificant development of moyamoya vessels. The lack of moyamoya vessel development may be explained by the suppression of tyrosine kinases that are responsible for angiogenesis...

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Moyamoya disease is a progressive nonatherosclerotic stenosis of the terminal segments of the arteries of the Circle of Willis. Hemorrhagic presentation is a life-threatening condition, associated with an increased risk of rebleeding and ischemic events.1-7 We present the case of a 65-year-old woman with a right intracerebral hemorrhage who underwent emergency hematoma evacuation without bone flap replacement. The investigation confirmed the diagnosis of Moyamoya disease and demonstrated hypoperfusion of the right cerebral hemisphere...

The anterior communicating artery (ACoA) plays a pivotal role in maintaining cerebral hemodynamics, as its diameter is a major determinant of blood collateralization through the circle of Willis following internal carotid artery occlusion. While variations of this artery are not uncommon, data on their clinicopathologic relevance are limited. In this report, we present our observation from a fresh cadaver of a male individual who had succumbed to cardiac causes. The circle of Willis displayed a duplicated ACoA with atherosclerosis that predominantly affected the posterior horn while sparing the anterior horn...

This case report details the pathological findings of a vessel wall identified as the bleeding point for intracranial hemorrhage associated with Moyamoya disease. A 29-year-old woman experienced intracranial hemorrhage unrelated to hyperperfusion following superficial temporal artery-middle cerebral artery bypass surgery. A pseudoaneurysm on the lenticulostriate artery (LSA) was identified as the causative vessel and subsequently excised. Examination of the excised pseudoaneurysm revealed a fragment of the LSA, with a disrupted internal elastic lamina and media degeneration...

RATIONALE: Hodgkin lymphoma, a lymphatic system cancer, is treated by chemotherapy, radiation therapy, and hematopoietic stem cell transplantation. Posterior reversible encephalopathy syndrome (PRES) is a rare neurotoxic effect associated with several drugs and systemic conditions. This case study emphasizes the potential risks of intensive chemotherapy regimens and postulates the impact of the circle of Willis variants on the heterogeneity of hemispheric lesions in PRES. PATIENT CONCERNS: A 42-year-old woman diagnosed with stage IIA nodular sclerosing Hodgkin lymphoma and chronic thrombocytopenia presented after 6 years of initial diagnosis and 4 years post-haploidentical transplant...

BACKGROUND AND PURPOSE: In-stent stenosis is commonly observed after stent implantation. There is no consensus on the contributing factors for in-stent stenosis, especially for aneurysms located at or beyond the circle of Willis in the anterior circulation. This study aimed to investigate the morbidity and determinants of in-stent stenosis in distal anterior circulation aneurysms following the implantation of Pipeline Embolization Devices. MATERIALS AND METHODS: Patients who underwent Pipeline Embolization Device treatment at our center between January 1, 2018, and June 15, 2023, were enrolled...

BACKGROUND: The Mongolian gerbil is an excellent laboratory animal for preparing the cerebral ischemia model due to its inherent deficiency in the circle of Willis. However, the low incidence and unpredictability of symptoms are caused by numerous complex variant types of the circle. Additionally, the lack of an evaluation system for the cerebral ischemia/reperfusion (I/R) model of gerbils has shackled the application of this model. METHODS: We created a symptom-oriented principle and detailed neurobehavioral scoring criteria...

PURPOSE: Unruptured intracranial aneurysms (UIAs) can cause aneurysmal subarachnoid hemorrhage, a severe and often lethal type of stroke. Automated labeling of intracranial arteries can facilitate the identification of risk factors associated with UIAs. This study aims to improve intracranial artery labeling using atlas-based features in graph convolutional networks. APPROACH: We included three-dimensional time-of-flight magnetic resonance angiography scans from 150 individuals...

Magnetic resonance angiography (MRA) contrast agents are extensively utilized in clinical practice due to their capability of improving the image resolution and sensitivity. However, the clinically approved MRA contrast agents have the disadvantages of a limited acquisition time window and high dose administration for effective imaging. Herein, albumin-coated gadolinium-based nanoparticles (BSA-Gd) were meticulously developed for in vivo ultrahigh-resolution MRA. Compared to Gd-DTPA, BSA-Gd exhibits a significantly higher longitudinal relaxivity ( r 1 = 76...