Origin Of Posterior Cerebral Artery Research Articles

Anatomical variations in posterior part of the circle of Willis and their associations with brain infarct in different vascular territories

BackgroundThe relationship between anatomical variations in circle of Willis and brain infarction is controversial. The purpose of this study was to evaluate the relationship between anatomical variations in posterior portion of the circle of Willis assessed by MR angiography (MRA) and ischemic infarction in different brain territories.MethodsThis cross-sectional study was conducted on consecutive patients who underwent brain MRI and MRA for suspected cerebrovascular accident. The frequency of anatomical variations including persistent fetal origin of posterior cerebral artery (fPCA) and hypoplastic/aplastic posterior communicating artery (PCoA) and their association with infarction in different intracranial vascular territories was assessed.ResultsIn total, 298 patients (155 male/143 female with mean age ± SD of 57 ± 15) were enrolled in the study and categorized into two groups with infarction (n = 142) and without infarction (n = 156). Sixty-three patients (21/1%) had fPCA and 231 (77.5%) had PCoA hypoplasia/aplasia. No significant correlation was identified between fPCA or PCoA hypoplasia/aplasia and presence of infarction. However, regarding the territories involved by infarction, the frequency of thalamus infarction was higher in subgroup with PCoA hypoplasia/aplasia, 17/101 (16.8%) compared to 1/41(2.4%) in the subgroup without ipsilateral PCoA hypoplasia/aplasia (p = 0.024). In two subgroups with and without ipsilateral fPCA variation, frequency of infarction in brain territories was not different significantly.ConclusionsIn patients with brain infarction, aplastic/hypoplastic ipsilateral PCoA is associated with higher incidence of thalamic territory infarction.

Influence of Foetal Origin of Posterior Cerebral Artery on Ischaemic Stroke

Introduction: Foetal origin of posterior cerebral artery is one among the common variants in the circle of willis. In case of cerebral injury due to thromboembolic stroke, the presence of foetal type of PCA may modify its severity and the territory involved. The purpose of this study is to review and to evaluate the potential clinical significance of foetal type PCA in ischaemic stroke. Aim: To analyse whether foetal PCA and its types are associated with ischaemic stroke. Materials and Methods: This is an analytical cross-sectional study conducted from January 2019 to January 2020 to assess the PCA in the 174 patients referred to Magnetic Resonance Imaging (MRI) Brain and diagnosed as ischaemic stroke. Data was entered using Excel sheet and analysed using R v.3. 5.1. Descriptive analysis was performed followed by bivariate analysis. Results: There is no statistically significant relationship between the presence of foetal PCA and ischaemic stroke and the p-value is 0.936. Conclusion: There is no significant association of presence or absence of partial or complete type of foetal PCA with ischaemic stroke. No significant association was also found between the presence of foetal PCA and vascular territory of infarct and laterality of ischaemic stroke.

Intracranial arterial variations and their relation with cerebral aneurysms: Analysis of 640 patients

Aim: To evaluate prevalence of cerebral arterial variations in Turkish population and association of the variations with cerebral aneurysmsMaterials and Methods: Digital subtraction angiography of 640 consecutive patients between January 2011-December 2013 were evaluated retrospectively. Patients with aneurysms were compared with patients without aneurysm to determine the effect of variations. Comparisons were made using Chi square or Fisher exact test for categorical variables and Student's t test or Mann Whitney U test for continuous variables.Results: The most common variation in the anterior circulation was hypoplasia of anterior cerebral artery A1 segment and the most common variation in the posterior circulation was fetal origin of the posterior cerebral artery. Hypoplasia and aplasia of the anterior cerebral artery A1 segment was significantly more frequent in patients with anterior communicating artery aneurysms than the control group (p:0.001). Prevalence of azygos anterior cerebral artery variation was higher in distal anterior cerebral artery aneurysms than the control group (p 0.001). There was no association between bihemispheric anterior cerebral artery and anterior communicating artery aneurysms (p = 0.453). Similarly, no significant association of fetal origin of posterior cerebral artery with posterior communicating artery aneurysms was found (p = 0.133). Conclusion: Prevalence of cerebral arterial variations in this study were compatible with literature. Some variations may play a role in development of aneurysms by alterations in hemodynamics and increasing shear wall stress. Further larger studies are needed to clarify the relation between variations in cerebrovascular structure and aneurysm formation.

Fetal origin of posterior cerebral artery related to poor collaterals in patients with acute ischemic stroke

The anatomic variation of Circle of Willis (CW) has been shown to have a great impact on its compensatory capacity during acute ischemic stroke. The purpose of the study was to evaluate the effect of variations in CW on collateral circulation in patients with acute ischemic stroke who had major artery occlusion. Patients with acute ischemic stroke within 4.5 h of stroke onset who had at least moderate severity of stroke (NIHSS ≥ 6), caused by major artery occlusion were included. Multiphase computed tomography angiography (CTA) was performed. Variations in CW on each patient were recorded and compared between those with poor collateral and intermediate-good collateral circulation. There were 66 patients. Mean NIHSS was 15. Forty patients had poor collateral circulation and 26 patients had intermediate-good collateral circulation. There were variations in CW: no visualized posterior communicating artery (PCOM) (31/66, 47%), fetal origin of posterior cerebral artery (25/66, 38%), one anterior cerebral artery, segment A1 (A1) hypoplasia or atresia (16/66, 24%), one PCOM (8/66, 12%), and complete CW (3/66, 5%). Fetal origin of posterior cerebral artery (PCA) was associated with poor collateral circulation (48% vs 23%, p-value = 0.046). This pilot study showed that the presence of fetal origin of PCA was associated with poor collateral circulation in patients with acute ischemic stroke caused by major artery occlusion.

A Cadaveric Study of Bilateral Configuration of Posterior Bifurcation of Posterior Communicating Artery in Indian Population

Various studies have been done regarding variations of circle of Willis, but few literatures are available about the detail configurations on Indian population. Posterior communicating artery is the main collateral channel between the vertebrobasilar and carotid system. It may act as a main source of blood flow via posterior cerebral artery if fetal configuration is present. Aim of the study is to see the bilateral configurations to compare the blood supply of both cerebral hemispheres via posterior cerebral artery in human cadavers. Fifty six formalin fixed brains were used for study. The specimens were classified into 3 types and 21 subtypes according to the configuration of the vessel of both hemispheres. As hemodynamic balance is dependent on the calibre of the vessel, the diameter of the arteries were also taken into consideration. Pearson's correlation had been done. In present study type I is 57.2%, type II is 37.5% and type III is 5.4%. Incidence of unilateral fetal type posterior cerebral artery is in high percentage (33.9%). Greatest diameter of posterior communicating artery is 3.8mm on right and 3.6mm on left side. Significant correlations also have been found between arterial segments of different types. It is expected that the study will help to enrich the knowledge about the arterial predominance of origin of posterior cerebral artery of both cerebral hemispheres in normal or variant cases and its effect on perfusion images.

Incomplete circle of Willis due to the bilateral abnormal origin of posterior cerebral arteries and bilateral absence of posterior communicating arteries

Variations in the circle of Willis are common. However, incomplete formation of circle of Willis due to bilateral abnormal origin of posterior cerebral arteries and bilateral absence of posterior communicating arteries is very rare. We report an unusual case of abnormal origin of the right posterior cerebral artery from the right internal carotid artery and continuation of basilar artery as left posterior cerebral artery in a 60-year-old male cadaver. The posterior communicating arteries were absent on both sides; hence, the arterial circle of Willis was incomplete. Furthermore, clinical and surgical importance of this case and relevant literature is discussed. The case of bilateral abnormal origin of posterior cerebral arteries, bilateral absence of posterior communicating arteries, and incomplete formation of posterior segment of circle of Willis is very rare. Precise knowledge of such variations in the cerebral vasculature is essential for anatomists, clinicians, and neurosurgeons.