Fetal Posterior Cerebral Artery Research Articles

Application of 3D-PCASL combined with t-ASL and MRA in the diagnosis of patients with isolated vertigo induced by posterior circulation ischemia

ObjectivesIsolated 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. Methods28 PCIVs (11 males, 17 females, aged from 55 to 83 years, mean age: 69.68 ± 9.01 years) and 28 healthy controls (HCs, 12 male, 16 female, aged from 56 to 87 years, mean age: 66.75 ± 9.86 years) underwent conventional magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI), MRA, 3D-PCASL, and t-ASL. We compared the incidence of anatomic variants of the posterior circle of Willis in MRA, cerebral blood flow (CBF) and anterior collateral blood flow on postprocessing maps obtained from 3D-PCASL and t-ASL sequence between PCIVs and HCs. Chi-square test and paired t-test were analyzed statistically with SPSS 24.0 software. Results7 PCIVs (7/28, 25%) and 6 HCs (6/28, 21%) showed fetal posterior cerebral artery (FPCA) on MRA, including 1 HC, and 6 PCIVs with FPCA appeared hypoperfusion. 18 PCIVs (64%) and 2 HCs (7%) showed hypoperfusion in the posterior circulation (PC), including 1 HC and 7 PCIVs displayed anterior circulation collateral flow. Chi-square analyses demonstrated a difference in PC hypoperfusion between PCIVs and HCs, whether in the whole or FPCA-positive group assessment (P < 0.05). Paired t-test showed that the CBF values were significant difference for the bilateral PC asymmetrical perfusion in the PCIVs (P < 0.01). When compared to the bilateral PC symmetrical non-hypoperfusion area in the PCIVs and HCs, the CBF values were not significant (P > 0.05). The CBF values of the PC in PCIVs were lower than in HCs (P < 0.05). The reduction rate in the hypoperfusion side of the bilateral PC asymmetrical perfusion of the PCIVs ranged from 4% to 37%, while the HCs reduction rate was 7.7%. The average PC symmetrical perfusion average reduction rate of the PCIVs was 52.25%, while the HCs reduction rate was 42.75%. Conclusion3D-PCASL is a non-invasive and susceptible method for detecting hypoperfusion in PC, serving as a potential biomarker of PCIV. The suspected hypoperfusion in PC may be attributed to the emergence of FPCA and the manifestation of anterior collateral flow when combining t-ASL and MRA sequences. These findings demonstrated that 3D-PCASL combined with t-ASL and MRA sequences are the potential method to identify PCIV, leading to early diagnosis of PCIV and reducing the risk of progressing into infarction.

Abstract TP178: Impact of Fetal PCA on Ipsilateral Carotid Artery Stiffness: Results From Northern Manhattan Stroke Study (NOMAS)

Introduction: The wall stress is the major contributor of arterial stiffness, which is well-known risk factor for cardiovascular diseases. The interindividual variability of the Circle of Willis affects blood flow redistribution intracranially. The fetal posterior cerebral artery (fPCA) is associated with larger carotid arteries due to increased brain territory supplied by the anterior circulation. Thus, an fPCA increases blood flow in the ipsilateral carotid artery and could plausibly increase ipsilateral carotid artery stiffness. Methods: We included participants from the multi-ethnic community-based Northern Manhattan Stroke Study (NOMAS) cohort with available time-of-flight MRA. High-resolution B-mode ultrasound of the right common carotid artery (CCA) evaluated markers of arterial stiffness, including diastolic diameter (DD), strain (systolic diameter - DD/DD), cIMT (carotid intima-media thickness), and stiffness (systolic blood pressure - diastolic blood pressure/strain). We used multivariable regression analyses to calculate odds ratios and beta values, examining the association of fPCA and markers of stiffness. Results: Among 1,210 NOMAS (mean age 70 ± 9 years, 61% women, 66% Hispanic) participants with available MRA, 151 (12.5%) participants had a right fPCA, and 129 (10.7%) had a left fPCA. In models adjusted for demographics, vascular risk factors, and height, right fPCA was associated with a higher ipsilateral CCA diastolic diameter (B = 0.31, p=0.001) and strain (B=0.04, p=0.02). Notably, no similar association was found between the left fPCA and contralateral carotid measures (Table 1). Conclusion: A fetal PCA associated with ipsilateral markers of cervical carotid stiffness. This research provides valuable insight into the changes in demands resulting from the variability of the circle of Willis and the extracranial correspondence of such demand.

Circulus Willis Anomalies Diagnosed with CT Angiography and Evaluation of Their Relations with Ischemic Stroke

Our aim in this study is examining the frequency of posterior communicating artery (PCoM), Anterior Cerebral Artery A1 segment (ACA AI) and Fetal type posterior cerebral artery (FPCA) anomalies and their effects on ischemic stroke by retrospectively analyzing examinations of Computerized Tomography Angiography (CTA) taken in our hospital within 2017. 22 cases (26.5%) diagnosed with bilateral hypoplastic / aplastic PCoA anomaly, were diagnosed with anterior circulation infarct, 24 cases (28.9%) were diagnosed with posterior circulation infarct, but 37 cases (44.6%) were not diagnosed with ischemic stroke. 17 (37.8%) of the cases who have unilateral hypoplastic / aplastic PCoA anomaly, were diagnosed with anterior circulation infarct, 14 cases (31.1%) were diagnosed with posterior circulation infarct. 13 (26%) of 50 cases diagnosed with unilateral hypoplastic / aplastic ACA A1 segment, were diagnosed with anterior circulation infarct, 10 cases (20%) were diagnosed with posterior circulation infarct. 27 cases (54%) were not diagnosed with ischemic stroke. Both of 2 cases diagnosed with bilateral hypoplastic / aplastic ACA A1 segment, had anterior circulation infarct. 4 (30.8%) of 13 cases diagnosed with unilateral FPCA anomaly, were diagnosed with anterior circulation infarct, 3 cases (23.1%) were diagnosed with posterior circulation infarct, 6 cases (46.2%) did not have ischemic stroke symptoms. In conclusion, even though these variations’ role in optimum stroke prophylaxis in individuals having one or more stroke risk factors, has not determined yet, there is no doubt that clinical researcher will eliminate these uncertainties in future studies.

Association of brain arterial diameters with demographic and anatomical factors in a multi-national pooled analysis of cohort studies.

Brain arterial diameters are markers of cerebrovascular disease. Demographic and anatomical factors may influence arterial diameters. We hypothesize that age, sex, height, total cranial volume (TCV), and persistent fetal posterior cerebral artery (fPCA) correlate with brain arterial diameters across populations. Participants had a time-of-flight MRA from nine international cohorts. Arterial diameters of the cavernous internal carotid arteries (ICA), middle cerebral arteries (MCA), and basilar artery (BA) were measured using LAVA software. Regression models assessed the association between exposures and brain arterial diameters. We included 6,518 participants (mean age: 70 ± 9 years; 41% men). Unilateral fPCA was present in 13.2% and bilateral in 3.2%. Larger ICA, MCA, and BA diameters correlated with older age (Weighted average [WA] per 10years: 0.18mm, 0.11mm, and 0.12mm), male sex (WA: 0.24mm, 0.13mm, and 0.21mm), and TCV (WA: for one TCV standard deviation: 0.24mm, 0.29mm, and 0.18mm). Unilateral and bilateral fPCAs showed a positive correlation with ICA diameters (WA: 0.39mm and 0.73mm) and negative correlation with BA diameters (WA: -0.88mm and -1.73mm). Regression models including age, sex, TCV, and fPCA explained on average 15%, 13%, and 25% of the ICA, MCA, and BA diameter interindividual variation, respectively. Using height instead of TCV as a surrogate of head size decreased the R-squared by 3% on average. Brain arterial diameters correlated with age, sex, TCV, and fPCA. These factors should be considered when defining abnormal diameter cutoffs across populations.

Abstract 104: Fetal Posterior Cerebral Artery (PCA) Occlusion from Occluded Cavernous ICA Stent

Introduction Posterior Cerebral Artery (PCA) is a medium vessel occlusion (MVO) which is 5‐10% of all acute ischemic events. Safety and efficacy of mechanical thrombectomy in posterior circulation MVO is unclear compared to medical treatment only (1). There is concern that fragility of distal, smaller vessels may have an increased risk of procedural complications (e.g., arterial dissection and or perforations). More people are getting flow divertors over the years and rate of flow diverter of ICA occlusion is 0.05%‐0.08% (2). Here we present a case of embolic fetal PCA stroke with ICA stent occlusion. Methods We report a case of fetal origin posterior cerebral artery occlusion from ICA with literature search of Pubmed. Results 77 years old female with left cavernous‐ICA stent presented from a rehab facility with complaints of word finding difficulty, confusion, right hemiparesis, right sided neglect, and visual disturbance. In the emergency department (ED), her NIHSS was 28. ED presentation was 2.5 hrs after the last known well (LKW). Of note, patient had a with left cavernous‐ICA stent placement a month before the presentation and was noncompliant to antiplatelets. CT head was negative for intracranial bleeding and ASPECT score was 7. CT angiography head and neck was obtained, showing new complete interval occlusion of the intracranial extradural left ICA with reconstitution of distal branches through anterior communicating artery. Patient received IV thrombolytics, intubated for airway protection and was transferred to a comprehensive stroke center for possible mechanical thrombectomy. Time of the arrival was approximately 6 hours after the LKW, reexamination was hindered by the sedation and intubation but was concerning for possible PCA occlusion rather than ICA occlusion. As the localization of ischemic area was unclear, CT perfusion (CTP) was obtained. CTP showed 27 ml penumbra without core infarct in left PCA territory. As fetal origin of left PCA from ICA is occluded, without ability to access through occluded stent, noted risk of left ICA complications with attempts to recanalize stent for noted PCA hypoperfusion outweigh the benefits. With the exam improvement post thrombolytics administration and small penumbra, mechanical thrombectomy was not indicated. Conclusion In acute large vessel occlusion, utility of CT perfusion (CTP) usually recommended after 6 hours from last well known. In this case, patient presented within the 6 hours but the reexamination post thrombolytics was not localizing to suggest large vessel occlusion (LVO) and the territory at risk was unclear. We described a left intracranial ICA flow diversion occlusion without anterior circulation ischemia and left PCA ischemia demonstrated. In this case, CTP was employed to differentiate the territory at risk for triage to appropriate intervention, to differentiate the LVO vs MVO.

Abstract 197: Mechanical Thrombectomy Of Basilar Artery Occlusion On A Hypoplastic Vertebrobasilar Circulation

Introduction Basilar artery occlusion (BAO) is one of the most severe acute ischemic strokes which carries high mortality and morbidity risk. Mechanical thrombectomy (MT) has been used as a promising treatment for BAO. However, the vertebral‐basilar anatomy is more challenging for MT compared to the anterior circulation due to several congenital variants such as hypoplastic vertebral artery, fenestration on the vertebrobasilar junction, or chronic asymptomatic occlusions of vertebral arteries, and tortuous subclavian arteries and vertebral arteries (VAs). Here, we described a BAO case with hypoplastic vertebrobasilar arteries, which was successfully treated with thrombectomy using the direct aspiration technique. Methods Electronic Medical Records review of a patient with acute basilar artery occlusion stroke. Results 55‐year‐old healthy gentleman presented to ER with acute onset with confusion, dysarthria, left‐sided weakness, and right facial droop. Initial NIHSS was 12. CT angiography (CTA) head and neck showed basilar artery was occluded in the distal one third segment. Because of the right fetal posterior cerebral artery and prominent left posterior communicating artery, his bilateral VAs and basilar artery were underdeveloped. The left VA appeared to be slightly bigger than the right one. After the patient received IV tPA, he was taken for mechanical thrombectomy. A Ballast catheter was placed in the left subclavian artery near the left VA origin. The conventional angiography showed the left VA was 2.8 mm and proximal basilar was about 2.1 mm. The Zoom 35 aspiration catheter was then used for mechanical thrombectomy. A complete basilar recanalization was achieved on the first pass. The patient improved after the MT. His NIHSS on discharge was 0. Conclusion The benefits of MT on BAO remain unknown despite several clinical trials. One of the reasons is due to more challenged vascular anatomy compared to anterior circulation. Underdevelopment of unilateral VA was commonly seen in posterior circulation ischemic strokes. But the underdevelopment of bilateral VAs with basilar arteries in BAO cases was rare and more difficult to treat. The Zoom 35 aspiration catheter provided a great advantage for this case with its smaller outer diameter, good navigation ability, and great aspiration efficacy. Our experience suggested a direct aspiration first pass technique (ADAPT) has an advantage on BAO, especially in the congenitally underdeveloped vertebrobasilar arteries.

How I do it? Preoperative Microsoft HoloLens 2 planning-assisted surgical clipping of a fetal posterior cerebral artery aneurysm.

The treatment of intracranial aneurysms has predominantly shifted towards endovascular strategies, but complex cases still necessitate microsurgery. Preoperative stimulation can be beneficial for inexperienced young neurosurgeons in preparing for safe microsurgery. A 72-year-old female with a left irregular fetal posterior cerebral artery (PCA) aneurysm underwent clipping repair. Microsoft HoloLens 2, utilizing mixed reality technology, was employed for preoperative stimulation and anatomical study. During the operation, we successfully identified the planned relationship between the aneurysm and the fetal PCA. The patient was cured without any complications. We hope that this report will highlight the significance of Microsoft HoloLens 2 in microsurgical planning and education.

Bilateral duplicated hypoplastic superior cerebellar arteries one of which originates from a full-type fetal posterior cerebral artery.

The association of bilateral duplication of the superior cerebellar artery with an origin from the posterior cerebral artery is rare but of great interest to anatomists, radiologists, and surgeons. This article reports bilateral duplicated hypoplastic superior cerebellar arteries, one of which arises from a full-type fetal cerebral artery. A 59-year-old woman admitted to the neurosurgery department for a subarachnoid hemorrhage underwent a brain CTA with 3D reconstruction using «3D slicer 4.11» software. Brain CTA and the 3D model were used to analyze the configuration of the posterior circulation. CTA images and the 3D model showed an unusual configuration of the posterior circulation. The basilar artery prolonged the left vertebral artery, while the right vertebral artery ended in the right posterior inferior cerebellar artery. On both sides, a full-type fetal posterior cerebral artery and duplicated hypoplastic superior cerebellar artery were observed. Three cerebellar arteries arose from the basilar artery, while the fourth one emerged from the right fetal posterior cerebral artery. Knowledge of such a configuration of the posterior circulation and others is necessary before radiological and surgical procedures. It helps to understand hemodynamic events, and neurovascular conflicts, improve revascularization procedures, and avoid surgical arterial and nervous injuries.

Efficacy and safety of fetal posterior cerebral artery stented coil embolization for fetal posterior cerebral aneurysms.

Aneurysms at the origin of the fetal posterior cerebral artery (fPCA) often show fPCA bifurcation from the aneurysm dome, impeding complete embolization and dense coil packing. The recanalization rate for fPCA aneurysms is therefore high. This study aimed to evaluate the efficacy and safety of stenting into fPCA for aneurysms with fPCA incorporated into the aneurysm to determine whether stenting can provide effective embolization results and prevent recanalization. A total of 19 consecutive coil embolization procedures between February 2012 and June 2022 for unruptured fPCA aneurysms with fPCA branching from the dome of the aneurysm were divided into two groups: non-stenting (NS) group (n = 11) and stenting into fPCA (PS) group (n = 8). Data were obtained retrospectively and compared regarding embolization results, complications, and recanalization. Compared with the NS group, the PS group achieved significantly higher complete occlusion rate and packing density (p < 0.001, p = 0.01, respectively). No symptomatic complications were observed in the PS group. Both immediately after stenting and at the 1-year follow-up, no stent kinking, stenosis, occlusion, or malposition were observed in any patients in the PS group. During 1-year follow-up, the cumulative minor and major recanalization-free rate after coil embolization for fPCA aneurysms were significantly higher in the PS group compared with the NS group (p = 0.022, 0.0024, respectively). Stenting into fPCA for aneurysms with fPCA incorporated into the aneurysm achieved high-density complete embolization without increasing complications, and prevented recanalization. The fPCA stent-assisted coil embolization can offer an alternative treatment for fPCA aneurysms.

Anatomical differences of intracranial arteries according to sex: a systematic review and meta-analysis

Background and PurposeIntracranial aneurysms are more common in women than in men. Some anatomical variants of the circle of Willis (CoW) are associated with a higher risk of developing intracranial aneurysms. We hypothesized that variations of the CoW are sex dependent which may partly explain why intracranial aneurysms are more common in women. We systematically reviewed and meta-analyzed the literature to compare the presence of anatomical variations of the CoW between women and men in the general population. Material and MethodsA systematic search in Pubmed and EMBASE using predefined criteria, following the PRISMA guidelines was performed. The presence of different CoW anatomical variants and a complete CoW was compared between women and men using an inverse variance weighted random effects meta-analysis to calculate relative risks (RR) with 95% confidence intervals (95% CIs). ResultsFourteen studies were included reporting on 5478 healthy participants (2511 women, 2967 men). Bilateral fetal type posterior cerebral arteries (RR 2.79; 95%CI 1.65–4.72, I2=0%), and a complete CoW (RR 1.24, 95%CI 1.13–1.36; I2=0%) were more prevalent in women than in men. The variants absence or hypoplasia of one of the anterior cerebral arteries (RR 0.58, 95%CI 0.38–0.88, I2=57%) and hypoplasia or absence of both posterior communicating arteries (RR 0.79, 95%CI 0.71–0.87, I2=0%) were more prevalent in men. ConclusionsSeveral anatomical variations of the CoW are sex dependent, with some variants being more common in women while others in men. Future research should assess how these sex-specific CoW variants relate to the sex-specific occurrence of intracranial aneurysms.

Fetal posterior cerebral artery in pediatric and adult moyamoya disease: A single-center experience of 480 patients

PurposeIn past pediatric and adult cohort studies of moyamoya disease, the fetal posterior cerebral artery has received less attention. Its relationship with the clinical manifestations and collateral circulation of moyamoya disease or ipsilateral cerebral hemispheres remains unclear. MethodWe summarize the clinical features of patients with and without fetal posterior cerebral artery moyamoya disease from consecutive cases.We explored the relationship between fetal posterior cerebral arteries and collateral circulation in the ipsilateral cerebral hemispheres, as well as differences among different subgroups of patients.According to the morphology, the fetal posterior cerebral artery is divided into complete fetal posterior cerebral artery and partial fetal posterior cerebral artery. Clinical features were classified as: infarction,hemorrhage,and non-stroke in unilateral/bilateral cerebral hemispheres. Collateral circulation is divided into extracranial vascular compensation and leptomeningeal collateral circulation. Digital subtraction angiography and CT/MR were used to evaluate the blood flow status and clinical characteristics of patients with moyamoya disease. ResultA total of 960 cerebral hemispheres from 142 pediatric patients and 338 adult patients were included in the study. A total of 273 (56.9%) patients had 399 cerebral hemispheres (41.6%) with fetal posterior cerebral arteries. Adults with fetal posterior cerebral arteries had lower rates of infarction (24.6%vs37.3%, P =0.005) and were less likely to have bilateral stroke (8.4%vs11.5%, P =0.038). Cerebral hemispheres with fetal posterior cerebral artery were more likely to have anterior cerebral artery and middle cerebral artery stenosis and less likely to have occlusion (P =0.002, 0.001), and less likely to involve the posterior circulation (P < 0.001). The cerebral hemispheres of the fetal posterior cerebral artery had higher leptomeningeal collateral circulation scores. There are significant differences in extracranial vascular compensation between cerebral hemispheres with and without fetal posterior cerebral artery. Adult patients with fetal posterior cerebral artery were more advanced in Suzuki stage (P =0.017). ConclusionsOur results suggest that fetal posterior cerebral artery is associated with infarct manifestations in pediatric and adult moyamoya disease. In the cerebral hemispheres, the fetal posterior cerebral artery is associated with ipsilateral hemispheric anterior and posterior circulation artery injury, extracranial vascular compensation, leptomeningeal collateral circulation compensation, and infarction. Adult patients with fetal posterior cerebral artery were more advanced in Suzuki stage.

Abstract Number ‐ 223: Spontaneous Revascularization of Completely Occluded Internal Carotid Artery: Case Report

Introduction Occlusion of the internal carotid artery (ICA), caused by atherosclerotic thrombosis, arterial embolism, or dissection, is associated with high morbidity and mortality of acute stroke. Commonly, these lesions are managed with aggressive medical treatment due to their chronic and usually irreversible nature. Spontaneous recanalization of the occluded ICA has been described in rare instances. Methods We present a report here on three cases with spontaneous recanalization of complete occluded carotid arteries. Results Our first patient was a 62‐year‐old male with a history of hypertension, who presented with transient left eye vision loss. CT angiography of the head and neck (CTA HN) demonstrated left ICA complete occlusion while the left middle cerebral artery (MCA) and anterior cerebral arteries (ACA) were patent. He was treated with apixaban. At the two‐month follow‐up, the repeat CTA HN demonstrated complete recanalization of the left ICA. The etiology of the occlusion remained cryptogenic. Our second patient was a 71‐year‐old male with a prior history of right carotid endarterectomy, peripheral vascular disease, coronary artery disease, hypertension, and dyslipidemia, who presented with acute right MCA stroke. Work‐up with CTA HN demonstrated right ICA complete occlusion. He was treated medically with aspirin and clopidogrel. Six months later, he presented with a two‐week history of intermittent confusion and left‐sided weakness. His MRI brain was negative foracute stroke. Interestingly, CTA HN demonstrated that the right ICA had complete recanalization. The cause of carotid thrombosis remained cryptogenic. Our third patient was a 46‐year‐old female with a history of hypertension, hyperlipidemia, remote low‐speed vehicle collision, and cervical spine chiropractic treatment (the last neck manipulation was about two years prior), presenting with sudden onset dizziness, right‐sided neck pain, and left homonymous hemianopia. Brain MRI showed acute right posterior cerebral artery (PCA) stroke. CTA HN revealed occlusion of the right ICA with a flare‐up appearance suggestive of a carotid dissection. She also had a right fetal PCA. She was treated medically with rivaroxaban. Four months later, a follow‐up MR angiogramof the neck showed a fully revascularized right ICA. Her hypercoagulable workup revealed that she had a rare form of breast cancer. Conclusions Although ICA occlusion is generally considered chronic and irreversible, our case series suggests that the lesion can have spontaneous recanalization with medical treatment. Further studies of characterizing carotid occlusion to predict recanalization are warranted.

Abstract TMP64: Association Of Brain Arterial Diameters With Demographic And Anatomical Factors In A Multi-national Pooled Analysis Of Cohort Studies

Objectives: Brain arterial dilation is an increasingly recognized cerebrovascular disease marker. However, demographic and anatomical factors may influence brain arterial diameters within the normal spectrum. We hypothesize that age, sex, height, total cranial volume (TCV) and fetal posterior cerebral arteries (fPCA) presence correlate with brain arterial diameters across diverse populations. Methods: We included participants with available time-of-flight MRA from 9 cohort studies across the United States (4), Ecuador (1), Venezuela (1), South Africa (1) and Singapore (2). Arterial diameters of the basilar artery (BA), cavernous internal carotid arteries (ICAs) and middle cerebral arteries (MCAs) were measured using LKEB Automated Vessel Analysis (LAVA) software. Linear regression models were fitted to assess the association between brain arterial diameters and exposures. The R-squared was calculated to assess the extent of brain arterial diameter variation explained by the variables studied. Results: The sample included 6,269 participants (mean age 68 years; 42% men). Unilateral fPCA was found in 12.6% and bilateral fPCAs in 3.0%. Older age, male sex and TCV were uniformly correlated with larger BA, ICA and MCA diameters (Table). Unilateral and bilateral fPCAs showed a negative correlation with BA diameter and a positive correlation with ICA diameters in a dose-dependent manner. Models fitted for age, sex, TCV, and fPCA presence explained on average 24, 16 and 12 % of the BA, ICAs and MCA diameter interindividual variation, respectively. Using height instead of TCV decreased the R-squared by 2% on average. Conclusions: In this pooled analysis of cohort studies, we found brain arterial diameters consistently correlate with age, sex, TCV and fPCA presence. These factors should be considered to define abnormal arterial diameter cut-offs across populations. If resources are limited or if bedside applicability is desired, height could be used instead of TCV.

The Fetal Type of Posterior Cerebral Artery.

Background and Objectives: Anatomical variations of the arterial circle of Willis (cW) are common. A posterior cerebral artery (PCA) fed mostly or exclusively from the internal carotid artery is a fetal PCA (FPCA), partial (p-FPCA), or full/complete (f-FPCA), respectively. Because FPCA occurs in different anatomical configurations of the cW sides, we aimed to document in detail these morphological possibilities of FPCA within the cW. Materials and Methods: FPCAs were documented on a retrospective set of 139 computed tomography angiograms. Results: FPCAs were found in thirteen cases, nine males and four females. In 7/13 cases there were two modified sides of the cW. In 5/13 cases there were three altered sides of the cW. Another case with FPCA showed four altered sides of the cW. In 10/13 cases, FPCA was unilateral and in the other three cases it was bilateral. Compared to the overall group, unilateral p-FPCAs were found in 1.43%, while unilateral f-FPCAs were found in 5.75%. A bilateral p-FPCA-f-FPCA combination was found in 0.71% and a bilateral f-FPCA-f-FPCA combination occurred in 1.43%. An anatomically isolated ICA was found in just one case with bilateral f-FPCA (0.71%). In 7/13 FPCA cases there were arterial variants exclusively in the posterior cW. In the other 6/13 FPCA cases, there were variants in both anterior and posterior circulation. There were no statistically significant associations of FPCA with sex or age. The higher prevalence of right-sided FPCA was not statistically significant. Conclusions: Anatomical assessments of cW should be performed on a case-by-case basis, as they may correspond to different cW morphologies.

Morphological evaluation of the risk of posterior communicating artery aneurysm rupture: a mirror aneurysm model.

The aim of this study was to use morphological parameters of mirror posterior communicating artery (PCoA) aneurysms to evaluate aneurysm rupture risk. The morphological parameters of 45 pairs of ruptured mirror PCoA aneurysms were analyzed. Conditional univariate and multivariate logistic regression of the following paired morphological parameters was performed: aneurysm with a daughter sac, aneurysm height, aneurysm width, neck width, internal carotid artery diameter, PCoA diameter, flow angle, PCoA angle, aspect ratio, bottleneck factor, size ratio, height/width ratio, fetal posterior cerebral artery, and aneurysm with height > width. A scoring system was established according to the odds ratios (ORs). The receiver operating characteristic was used to test the prediction accuracy of this scoring system in the authors' database of 523 PCoA aneurysms and the threshold value was used to define higher risk. Aneurysm width (OR 1.676, p = 0.014), aneurysm with daughter sac (OR 7.775, p = 0.016), and aneurysm with height > width (OR 9.067, p = 0.012) were independent risk factors for rupture. The scoring system consisted of aneurysm width (1 point per mm), aneurysm with a daughter sac (5 points), and aneurysm with height > width (5 points). The area under the curve (AUC) of the scoring system was 0.842, and its threshold value was 7.97. A score ≥ 8 points was defined as higher risk. The AUC using this definition was 0.802. Aneurysm width, aneurysms with height > width, and aneurysms with a daughter sac were independent risk factors for PCoA aneurysm rupture. The scoring system devised in this study accurately predicts rupture risk.

Reperfusion Therapy in Patients with Acute Stroke with the Willis Polygon Variant – A Fetal Posterior Cerebral Artery

ABSTRACT Aim: The Willis polygon variant, specifically the presence of a fetal posterior cerebral artery (fPCA), can have implications for the treatment and prognosis of patients with acute stroke. This study aimed to investigate the effect of fPCA variations on treatment, follow-up, and prognosis in patients with acute stroke who underwent reperfusion therapies. Materials and Methods: The study analyzed a total of 62 patients, including 33 without any posterior system variant (normal group) and 29 with only the fPCA variant (variant group). Demographic characteristics, clinical features, and computed tomography (CT) findings were compared between the two groups. Treatment methods, acute stroke therapies, and clinical outcomes were evaluated. Results: No significant differences were observed in age, sex, smoking status, or comorbidities between the normal and fPCA groups. Cardiac parameters were similar between the groups. Treatment approaches, artery territories, acute stroke therapies, and time intervals did not differ significantly between the two groups. The National Institutes of Health Stroke Scale scores, modified Rankin Scale scores, and CT findings were also similar between the groups. A significant difference was observed in the presence of hemorrhage at 24 h, with higher rates in the normal group. Conclusion: The presence of fPCA does not significantly influence age-related risk factors or comorbidities in patients with acute stroke. Treatment approaches and clinical outcomes were similar regardless of the presence of fPCA, except for a higher risk of hemorrhage in the normal group. The lateral status of the variants did not significantly impact the distribution of risk scores and CT findings.

Duplicated fetal posterior cerebral artery in a patient with a ruptured fetal posterior cerebral artery aneurysm: a cerebrovascular variant.

The most common neurovascular variant is the fetal posterior cerebral artery (FPCA), in which the P1 branch is absent or hypoplastic, and the majority of P2 supply is derived from the anterior circulation. While there are reports of hyperplastic anterior choroidal arteries (AChA) with supply to the temporo-occipital and calcarine regions, no reports of a duplicated FPCA exist. This case report describes a patient with a ruptured right FPCA aneurysm. Digital subtraction angiogram (DSA) revealed an artery with origin distal to the FPCA associated with the aneurysm. This was not consistent with a typical AChA. The FPCA associated with the aneurysm had the typical origin, course, and supply of a FPCA. The distal FPCA had a similar course of a typical FPCA with significant supply to the typical PCA territory. The patient underwent successful clipping of the aneurysm, and the duplicated FPCA was identified during the craniotomy. The features of this duplicate FPCA, which has not been previously described, are discussed in comparison to another variant, the hyperplastic, anomalous AChA. The artery described in this report does not fit the typical criteria of this AChA variant. Therefore, the authors outline this variant as a duplicated FPCA. Recognition of variant cerebrovascular anatomy is vital to neurosurgeons and interventional neuroradiology specialists. FPCA aneurysms require special management considerations and are often more challenging to treat. This report discusses a duplicated FPCA. To our knowledge, this is the first description of this variant. A duplicated FPCA carries important management considerations in the management of neurovascular pathology.

Association between Anatomical Variations of the Circle of Willis and Covert Vascular Brain Injury in the General Population

Background and Purpose: The circle of Willis (COW) is a circulatory anastomosis located at the base of the brain. Little is known about the association between covert vascular brain injury and COW configurations in the general population. We explored this relationship in a community-based Chinese sample. Methods: A total of 1,055 patients (mean age, 54.8 ± 8.9 years; 36.0% men) without intracranial arterial stenosis were included in the analysis. Magnetic resonance imaging was performed to evaluate the presence of imaging markers of covert vascular brain injury, including white matter hyperintensities (WMHs), lacunes, cerebral microbleeds (CMBs), enlarged perivascular spaces, and brain atrophy. Magnetic resonance angiography was used to classify the COW configurations according to the completeness, symmetry, and presence of the fetal posterior cerebral artery (FTP). The association between vascular lesions and variations in COW was analyzed. Results: Among the 1,055 patients, 104 (9.9%) had a complete COW. Completeness correlated with age (p = 0.001). Incomplete COW was positively associated with WMH severity (OR = 2.071; 95% CI, 1.004–4.270) and CMB presence (OR = 1.542; 95% CI, 1.012–2.348), independent of age and sex. The presence of FTP was associated with lacunes (OR = 1.878; 95% CI, 1.069–3.298), more severe WMHs (OR = 1.739; 95% CI, 1.064–2.842), and less severe enlarged perivascular spaces (OR = 0.562; 95% CI, 0.346–0.915). Conclusions: COW configuration was significantly related to various covert vascular brain injuries.

FRED flow diversion with LVIS protection of large posterior communicating artery aneurysm: the "FRELVIS" technique.

Treatment of wide-necked posterior communicating artery (PCoA) aneurysms is extremely challenging, especially in fetal posterior cerebral artery (PCA) configurations. This technical video demonstrates the nuances of an innovative use of flow diversion to treat a recurrent wide-necked PCoA aneurysm. This middle-aged patient presented with recurrence of a previously ruptured, coil-embolized PCoA aneurysm. Initial attempts at Comaneci-assisted coiling were unsuccessful because the coil herniated into the middle cerebral artery (MCA). Therefore, a low-profile visualized intraluminal support (LVIS) was placed in the fetal PCA across the aneurysm ostium and a flow diverter was placed in the internal carotid artery and MCA to constitute a Y-construct. The video can be found here: https://stream.cadmore.media/r10.3171/2022.7.FOCVID2262.

Inverted stent deployment technique for stent assisted coiling of wide-necked posterior communicating artery aneurysm: Technical report.

Wide-necked aneurysms of the posterior communicating artery associated with a fetal posterior cerebral artery that arises from the neck or dome of the aneurysm is a clinical scenario that poses a challenge to endovascular methods. A patient presented with spontaneous subarachnoid hemorrhage and was found to have a 4 × 3 × 3 mm posterior communicating artery aneurysm. Of note the aneurysm projected superiorly and a fetal posterior communicating artery aneurysm arose from the neck of the aneurysm. After multidisciplinary discussion a treatment strategy of endovascular stent-assisted coiling was chosen. Given the unique morphology of the aneurysm a novel stent-inversion maneuver was used, in which the stent was deployed from the posterior communicating artery into the distal supra-clinoid internal carotid artery. The patient tolerated the procedure well and complete aneurysm occlusion was achieved. This case demonstrates a novel stent inversion technique that can be used for stent-assisted coiling of certain challenging aneurysms.