Figure 2: MIPs of 1.5T (a) and 7T (b) PC MRA of the vasculature superior to the circle of Willis of a 39 year old, male volunteer. The acquisitions times for both sequences were about 5 minutes. Axial images were acquired with slices thickness of 0.75 mm. The 7T images depict third order branches of the circle of Willis, e.g. the paracentral artery. Ultrahigh Field (>7T) Time-of-Flight and Phas...

We studied the distribution pattern of serotonin-like immunoreactive nerve fibers in the major cerebral vessels of rabbit by an indirect immunofluorescence technique using whole-mount stretch preparations. The density of serotonin-like immunoreactive nerve fibers was greater in vessels of the posterior part of the circle of Willis compared with that in the anterior part. This is in contrast to ...

Results In this retrospective study, we analyzed 175 patients who presented at our outpatient stroke clinic between January, 2013 and June, 2015 with either unilateral symptomatic or asymptomatic carotid artery disease, and who had had CT angiography imaging performed. Demographic properties, carotid artery stenosis and the anomaly of the circle of Willis was recorded. Conclusion There was no...

INTRODUCTION The forming of the blood vessels network configuration at the base of the brain and interconnecting of blood vessels during the embryogenesis is directly related to the phylogenetic development of the brain and brain structures. A blood vessel configuration at the brain base, in the form of a ring or a hexagon, stands in direct relation to the perfusion needs of certain parts of th...

In a fetal variation of circle of Willis (CoW) there is an embryological defect of the primary collateral circulation. Besides the fact that collateral flow cannot develop between anterior and posterior circulation, the tentorium namely prevents cerebellar vessels from connecting to the supra-tentorium territory. Therefore patients with a fetal variation of circle of Willis could be more prone ...

BACKGROUND The circle of Willis is a major collateral pathway important in ischemic conditions. The aim of our study was to assess the structural characteristics of the circle of Willis within the Turkish adult population, along with variations and arteries involved in the measurement of diameters and lengths on cranial computed tomography angiography (CTA). MATERIAL AND METHODS One hundred a...

BACKGROUND AND PURPOSE Volume flow rates in the feeding arteries of the brain are measured to evaluate blood flow dynamics in vascular disease. Although these flow values are thought to be effected by anatomic variations in the circle of Willis, few reports have described the effect. This study reports on the relationship between variations in the circle of Willis and volume flow rates in the b...

BACKGROUND AND PURPOSE Flow Diverters (FD) are a new emerging therapy for intracranial aneurysms. Initial reports focused on the treatment of proximally located aneurysms. We report our experience with FDs in the treatment of aneurysms at and beyond the circle of Willis. METHODS We treated 30 aneurysms at and beyond the circle of Willis with FDs (silk and pipeline). Aneurysms were treated wit...

In 24 patients with cerebrovascular disease and 6 without organic brain lesions, the increased velocity of blood flow in both the internal carotid and vertebral arteries during a contralateral carotid compression was compared with the angiographic appearance of the circle of Willis. The flow velocity was measured using ultrasonic Doppler flowmetry. It was not possible to investigate fully the r...