Is fetal-type posterior cerebral artery a risk factor for intracranial aneurysm as analyzed by multislice CT angiography?

Rare simultaneous fetal posterior cerebral artery and conventional posterior cerebral artery duplication in a patient with a ruptured posterior communicating artery aneurysm: illustrative case

BACKGROUND

The fetal-type posterior cerebral artery (PCA) is defined as a variant anatomy in which the posterior communicating artery (PCOM) is larger than the hypoplastic or aplastic P1 segment of the PCA. The authors present the novel case of a patient with a duplicated right PCA in parallel with fetal-type and conventional PCAs supplying adjacent components of the PCA cerebral territory.

OBSERVATIONS

A 59-year-old woman presented with a modified Fisher Scale score 4 subarachnoid hemorrhage. A right irregular PCOM aneurysm that measured 9.5 mm × 4.5 mm × 4.5 mm arose from the base of a variant branch supplying a portion of the PCA, rather than a conventional PCOM, and was found on digital subtraction angiography. Following endovascular coil embolization, the patient was discharged home.

LESSONS

The fetal-type variant has implications for thromboembolic events. If an embolism occludes the anterior circulation in a patient with a fetal-type PCA, it may result in an infarct in the PCA territory. Awareness of cerebral arterial anatomy, including an atypical collateral supply, informs a treating team's latitude in tolerance of which sites must be preserved and which can be safely sacrificed. https://thejns.org/doi/10.3171/CASE23735.

Hemodynamic differences of posterior communicating artery aneurysms between adult and fetal types of posterior cerebral artery

BACKGROUND

The recanalization of posterior communicating artery (PCoA) aneurysms after endovascular treatment has been analyzed by various factors. However, the differences between adult and fetal types of posterior cerebral artery (PCA) have not been fully investigated. The main aim of this study was to investigate hemodynamic differences of PCoA aneurysms between adult and fetal types using computational fluid dynamics (CFD).

METHODS

Fifty-five PCoA aneurysms were evaluated by 3D CT angiography and divided into unruptured aneurysms with adult-type or fetal-type PCAs (19 cases, UA group; 9 cases, UF group) and ruptured aneurysms with adult-type or fetal-type PCAs (17 cases, RA group; 10 cases, RF group). These native aneurysms were analyzed by CFD regarding morphological and hemodynamic characteristics. To evaluate simulated endovascular treatment of aneurysms, CFD was performed using porous media modeling.

RESULTS

Morphologically, the RA group had significantly smaller parent artery diameter (2.91 mm vs. 3.49 mm, p=0.005) and higher size ratio (2.54 vs. 1.78, p=0.023) than the RF group. CFD revealed that the UA group had significantly lower oscillatory shear index (OSI) (0.0032 vs. 0.0078, p=0.004) than the UF group and that the RA group had lower WSS (3.09 vs. 11.10, p=0.001) and higher OSI (0.014 vs. 0.006, p=0.031) than the RF group, while the RF group presented significantly higher intra-aneurysmal flow velocity (0.19 m/s vs. 0.061 m/s, p=0.002) than the RA group. Porous media modeling of simulated treatment revealed higher residual flow volume in the fetal-type groups.

CONCLUSIONS

These results suggested that PCoA aneurysms with fetal-type PCAs had different morphological features and hemodynamic characteristics compared with those with adult-type PCAs, leading to high risks of recanalization.

Anatomical variations in the Circle of Willis and the formation and rupture of intracranial aneurysms: A systematic review and meta-analysis

Background

The anterior (AcomA) and posterior communicating arteries (PcomA) are two of the most frequent sites for intracranial aneurysms. Anatomical variations in the Circle of Willis (COW) are frequently observed in patients with AcomA and PcomA aneurysms. Strong evidence is needed to determine the pooled estimate of the effect of COW variations on the formation and rupture of these aneurysms.

Aim

This systematic review and meta-analysis aimed to establish the effect of COW variations on the formation and rupture of AcomA and PcomA aneurysms using available studies.

Summary of review

PubMed, Embase, and Web of Science databases were systematically searched for studies published in English before September 21, 2022. Studies investigating AcomA aneurysms and the hypoplastic/aplastic A1 segment of the anterior cerebral artery and PcomA aneurysms and hypoplastic/aplastic PcomA or fetal-type posterior cerebral artery (FTP) were included. The heterogeneity of the studies was assessed using Cochran Q-test and I² statistic. Pooled estimate was assessed using either a random- or fixed-effects model based on the heterogeneity of the studies. Among the 4,932 studies, 21 were eligible and included in the analysis. The presence of hypoplastic/aplastic A1 was significantly correlated with the formation [OR (95% confidence interval [CI]) = 7.97 (5.58, 11.39), P < 0.001] and rupture [OR (95%CI) = 1.87 (1.29, 2.72), P < 0.001] of AcomA aneurysms. Significant associations between FTP and both the formation [OR (95%CI) = 2.15 (1.41, 3.30), P < 0.001] and rupture [OR (95%CI) = 1.72 (1.26, 2.36), P < 0.001] of PcomA aneurysms were observed.

Conclusions

Significant associations were observed between COW variations and both the formation and rupture of AcomA and PcomA aneurysms. This can help in determining interventions for patients with aneurysms.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=225149, identifier: CRD42021225149.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Clinical characteristics of intracranial aneurysms in elderly patents over 70 years old: a retrospective observational study

Background

Although the characteristics of intracranial aneurysms (IAs) in different age groups have been well documented, they remain relatively unclear in elderly patients due to a lack of large sample studies.

Methods

Data from IA patients aged more than 70 years who were treated in our centre from January 2016 to January 2020 were retrospectively collected.

Results

A total of 290 elderly patients (75.9% female) with a mean age of 74.0 ± 4.7 years were analysed. Rupture occurred in 60.7% of patients, 38.6% of whom presented with meningeal irritation, and seizures were noted in 2.3%. A total of 48.9% of the patients with ruptured IAs had initial symptoms presenting with slow development, and the mean delay from ictus was prolonged to 264.2 ± 914.0 hours. In addition, 61.9% of the patients with ruptured IAs had lesions with a maximum diameter of less than 5 mm. A total of 30.3% of the patients had multiple aneurysms, 35.5% had aneurysms with irregular shapes and 54.8% had cerebrovascular atherosclerotic stenosis (CAS). Pulmonary infection (n = 138, 47.6%), hydrocephalus (n = 72, 24.8%), and thrombosis (n = 35, 12.1%) were common complications during hospitalization. By the end of the 1-year follow-up, 22.1% of the patients had unfavourable clinical outcomes, and the mortality rate was 23.4%.

Conclusions

Several characteristics regarding IAs in elderly patients were reported, including an obvious female predominance; mild, slow initial symptom development causing prolonged admission delay; a low incidence of meningeal irritation and seizures due to decreased electrophysiological activity of the neurons; increased percentages of CAS, multiple aneurysms, and aneurysms with daughter sacs causing a high risk of rupture even for small lesions; a high risk of complications during hospitalization; and relatively poor clinical outcomes.

Higher oscillatory shear index is related to aneurysm recanalization after coil embolization in posterior communicating artery aneurysms

BACKGROUND

The recurrence rate of posterior communicating artery (Pcom) aneurysms after endovascular treatment (EVT) is higher than that for aneurysms located in other sites. However, it is still unclear what mechanisms are responsible for the recanalization of cerebral aneurysms. In this investigation, we compared hemodynamic factors related with recanalization of Pcom aneurysms treated by endoluminal coiling using computational fluid dynamics (CFD) with high-resolution three-dimensional digital subtraction angiography images.

METHODS

Twenty patients were enrolled. A double-sinogram acquisition was performed with and without contrast injection after coil embolization to get true blood vessel lumen by relatively complementing the first sinogram with the second. Adaptive Cartesian meshing was performed to produce vascular wall objects for CFD simulation. The boundary condition for inlet (ICA) was set for dynamic velocity according to the cardiac cycle (0.8 s). Hemodynamic parameters were recorded at two specific points (branching point of Pcom and residual sac). The peak pressure, peak WSS, and oscillatory shear index (OSI) were recorded and analyzed.

RESULTS

The median age was 61.0 years, and 18 patients (90%) were female. During a median follow-up of 12 months, seven (35%) treated aneurysms showed recanalization. The median aneurysm volume was significantly higher, and aneurysm height and neck sizes were significantly longer in the recanalization group than those in the stable group. At the branching point of the Pcom, the peak pressure, peak WSS, or OSI did not significantly differ between the two groups. The only statistically significant hemodynamic parameter related with recanalization was the OSI at the aneurysm point. Multivariate logistic regression showed that with an increase of 0.01 OSI at the aneurysm point, the odds ratio for the aneurysm recanalization was 1.19.

CONCLUSIONS

A higher OSI is related with recanalization after coil embolization for a Pcom aneurysm.

Clinical and Morphological Characteristics of Ruptured Small (<5 mm) Posterior Communicating Artery Aneurysms

Context:

Small intracranial aneurysms (IAs) are considered to have a low risk of rupture; however, in clinical practice, we often encounter patients with subarachnoid hemorrhage (SAH) due to rupture of small IAs.

Aims:

This study aims to clarify the clinical and morphological characteristics of ruptured small IA, focusing on posterior communicating artery (PCoA) aneurysms as a prone site.

Settings and Design:

We retrospectively reviewed 102 consecutive patients with SAH due to ruptured PCoA aneurysm who underwent microsurgical or endovascular aneurysm repair between April 2013 and March 2018.

Subjects and Methods:

All PCoA aneurysms were diagnosed using three-dimensional rotation angiography or three-dimensional computed tomography angiography. Information regarding the following clinical characteristics was collected: age, sex, past medical history, current smoking, antithrombotic therapy, multiplicity, hydrocephalus, intracerebral hemorrhage, intraventricular hemorrhage, and World Federation of Neurosurgical Societies (WFNS) Grade on admission.

Statistical Analysis Used:

We analyzed factors of ruptured small IA, focusing on PCoA aneurysms using univariate and multivariate regression analyses.

Results:

Univariate and multivariate analyses revealed that low aspect ratio (AR) (odds ratio [OR] = 0.33, P = 0.01) and nonfetal type of PCoA (OR = 0.31, P = 0.02) might be independent characteristics of ruptured small PCoA aneurysms. However, age, sex, past medical history, WFNS grade, and treatment outcome were not different between the small and nonsmall PCoA aneurysms. The aneurysm size was not associated to the selection of treatment, proportion of complications, and treatment outcome.

Conclusions:

In cases of ruptured PCoA aneurysms, low AR and nonfetal type of PCoA might be associated with rupture of small aneurysms.

Application of three dimensional (3D) curved multi-planar reconstruction images in 3D printing mold assisted eyebrow arch keyhole microsurgery

OBJECTIVE

The application of multi-planar reconstruction of three dimensional (3D) curved surface in microsurgery of 3D printing mold assisted eyebrow arch keyhole approach was studied.

METHODS

Eighty patients with intracranial aneurysms who underwent treatment at our hospital were enrolled. The patients were divided into two groups: the traditional eyebrow keyhole approach microsurgery group (38 cases in the conventional treatment group) and the three-dimensional curved surface multi-plane reconstruction image combined with 3D printing technology assisted eyebrow keyhole approach microsurgery group (42 cases in the 3D printing assisted treatment group). The Hunt-Hess classification was used to make a preliminary estimation of the patient's condition. The 3D curved multi-planar reconstruction method was used to assist the surgical plan; CT scan was used to establish a 3D printing mold, and the patient's condition and surgical plan were accurately analyzed before surgery. The operative time and the size of the incision area were recorded; postoperative GOS score and postoperative complications were statistically investigated.

RESULTS

The 3D printing assisted treatment group (70.13 ± 15.56), (411.26 ± 10.38) mm² , the operative time and incision area were significantly shorter than the conventional treatment group (120.35 ± 20.46), (663.55 ± 13.54) mm² , p < .05); the GOS score showed that the 3D printing-assisted treatment group was significantly higher than the conventional treatment group (p < .05). The postoperative complication rate was significantly lower in the 3D print-assisted treatment group (9.52%) than in the conventional treatment group (47.36%, p < .05); the cure of intracranial aneurysms in the 3D printing assisted treatment group was more thorough than that in the conventional treatment group, and the difference was significant (p < .05).

CONCLUSION

Compared with the conventional eyebrow arch-hole approach microsurgery, the 3D surface multi-planar reconstruction image combined 3D printing assisted technology was safer and more effective, and the postoperative recovery was better and the incidence of complications was lower.

Sex differences in aneurysmal subarachnoid haemorrhage (aSAH): aneurysm characteristics, neurological complications, and outcome

BACKGROUND

Women are over-represented in aSAH cohorts, but whether their outcomes differ to men remains unclear. We examined if sex differences in neurological complications and aneurysm characteristics contributed to aSAH outcomes.

METHODS

In a retrospective cohort (2010-2016) of all aSAH cases across two hospital networks in Australia, information on severity, aneurysm characteristics and neurological complications (rebleed before/after treatment, postoperative stroke < 48 h, neurological infections, hydrocephalus, seizures, delayed cerebral ischemia [DCI], cerebral infarction) were extracted. We estimated sex differences in (1) complications and aneurysm characteristics using chi square/t-tests and (2) outcome at discharge (home, rehabilitation or death) using multinomial regression with and without propensity score matching on prestroke confounders.

RESULTS

Among 577 cases (69% women, 84% treated) aneurysm size was greater in men than women and DCI more common in women than men. In unadjusted log multinomial regression, women had marginally greater discharge to rehabilitation (RRR 1.15 95% CI 0.90-1.48) and similar likelihood of in-hospital death (RRR 1.02 95% CI 0.76-1.36) versus discharge home. Prestroke confounders (age, hypertension, smoking status) explained greater risk of death in women (rehabilitation RRR 1.13 95% CI 0.87-1.48; death RRR 0.75 95% CI 0.51-1.10). Neurological complications (DCI and hydrocephalus) were covariates explaining some of the greater risk for poor outcomes in women (rehabilitation RRR 0.87 95% CI 0.69-1.11; death RRR 0.80 95% CI 0.52-1.23). Results were consistent in propensity score matched models.

CONCLUSION

The marginally poorer outcome in women at discharge was partially attributable to prestroke confounders and complications. Improvements in managing complications could improve outcomes.

Clinical features and outcomes of PComA aneurysms originating from fetal posterior communicating arteries in a single institution

Background

The aim of this study was to retrospectively analyze our experience with the patients who underwent surgical treatment of posterior communicating artery (PComA) aneurysms originating from fetal posterior cerebral artery (fPCA) and analyze the risk factors for the postoperative radiological infarction and outcome.

Methods

From 2011 to 2020, we retrospectively reviewed 74 PComA aneurysms originating from fPCA in terms of the clinical and radiological features and obtained the follow-up data from the Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University. The relationships between these features and follow-up data were assessed with the univariate and multivariate analysis.

Results

In this series, 74 aneurysms were occurring at the origin of fPCAs. All the patients showed complete obliteration of their aneurysms. Full fPCA type tends to be a predictive factor for radiological infarction (univariate χ² = 5.873, P = 0.027; multivariate OR = 0.264, P = 0.060). Postoperative radiological infarction (univariate χ² = 12.611, P = 0.001; multivariate OR = 6.033, P = 0.043), rupture (univariate χ² = 4.514, P = 0.047; multivariate OR = 57.966, P = 0.044), and hypertension (univariate χ² = 5.301, P = 0.024; multivariate OR = 24.462, P = 0.029) tend to be the independent predictive factors for poor prognosis at 3 months after discharge.

Conclusions

In conclusion, we report a series of patients harboring aneurysms originating from the fPCA. Surgical clipping is a reliable strategy. Full fPCA type is related to postsurgical infarction. Postoperative radiological infarction, rupture, and hypertension tend to be the independent predictive factor for poor prognosis at 3 months after discharge.

Anomalous Origin of the Anterior Choroidal Artery Proximal to an Ipsilateral Fetal Posterior Cerebral Artery: Case Report of an Extremely Rare Anatomic Variant and Discussion of its Clinical Implications

The anterior choroidal artery (AChA) supplies important cerebral structures such as the internal capsule, optic tract, and lateral geniculate body. It is normally a branch of the communicating segment of the internal carotid artery (ICA) with significant neurological symptomatology if injured. Typically, the AChA originates distal to the posterior communicating artery (PCoA), but rare variants have previously been described. Such anatomical differences are particularly important entities, especially in the context of neuroendovascular procedures, as inadvertent damage to these arteries can have devastating consequences. In this case report, we present an unusual anatomical pattern of the right AChA arising proximal to an ipsilateral fetal PCA.

Morphological and clinical risk factors for the rupture of posterior communicating artery aneurysms: significance of fetal-type posterior cerebral artery

BACKGROUND

Posterior communicating artery (PcomA) aneurysm can be classified into sidewall or bifurcation types based on the anatomical variation of fetal-type posterior cerebral artery (fPCA). The aims of this study were to investigate the significance of fPCA as an independent risk factor for the rupture of PcomA aneurysm and to evaluate other associated morphological and clinical risk factors.

METHODS

We retrospectively reviewed clinical and radiological findings of 255 patients with PcomA aneurysms, which were treated in a single tertiary institute between January 2009 and December 2016. Univariate and multivariate analyses were performed to evaluate the associations between morphological and clinical variables and rupture status. Subgroup analysis was also performed based on the aneurysms with and without fPCA.

RESULTS

Fifty-five out of 255 PcomA aneurysms (21.6%) were associated with fPCA. Multivariate logistic regression analysis showed that the superior direction of aneurysm dome (OR 9.106, p = 0.007), the presence of a bleb (OR 4.780, p < 0.001), a high aspect ratio (OR 1.878, p = 0.045), and fPCA (2.101, p = 0.040) were significantly associated with PcomA aneurysm rupture. In the fPCA group, only the presence of a bleb varied significantly between ruptured and unruptured PcomA aneurysms. However, in the non-fPCA group, larger aneurysms, the superior direction of dome, the presence of a bleb, and a high aspect and dome-to-neck ratio were significantly higher in the ruptured aneurysm group than in the unruptured aneurysm group.

CONCLUSIONS

The results demonstrate that fPCA may be an independent risk factor for rupture, especially together with the presence of a bleb.

Proportion of Variant Anatomy of the Circle of Willis and Association with Vascular Anomalies on Cerebral CT Angiography

Background and Purpose

There is a wide variation in the anatomy of the CW in different individuals and population groups. The purpose of this study was to determine the proportion of variant anatomy of the circle of Willis (CW) and associated anomalies in patients with suspected cerebrovascular disease referred for cerebral computed tomography angiography (CTA) in two tertiary hospitals in Kenya.

Methodology

This was a cross-sectional descriptive study conducted on 94 patients referred for cerebral CTA at the Kenyatta and Nairobi hospitals from August 2017 to February 2018. MIP and 3D reformatted images were analyzed by two senior radiologists to determine the final configuration of the CW and presence of vascular pathology. Vessels with diameters <0.8 mm were considered to be absent or hypoplastic. Chen et al. classification was used to determine the final configuration of CW.

Results

Complete CW was seen in 37.2% (37.7% vs. 36.6% in males and females, respectively, p=0.909). Type A variant was the commonest anterior variant at 78.7%. Type E variant was the dominant posterior variant at 41.5%. Fetal PCA was demonstrated in 25.5%, unilateral > bilateral fetal PCA. Aneurysms were seen in 24.5% of patients. ACoA aneurysms were commonest at 43.6%. AVMs were seen in 8.5% of patients. Azygous ACA, fenestration, and duplication of vessels and persistent TA were not demonstrated. There is no significant association between aneurysms/AVMs and CW configuration.

Conclusion

The findings in this study demonstrate slight differences in the CW configuration. A higher proportion of complete anterior CW was seen in female patients. Type A anterior and type E posterior circulation variants were the commonest in both males and females. No significant association was demonstrated between CW configuration and occurrence of aneurysms/AVMs in this study. Various methods of classification of CW configuration have been proposed with no standardized method to date, thus the need for consensus building between neuroanatomists, neurologists, neurosurgeons, and neuroradiologists for ease of comparison between similar future studies on the CW.