Subarachnoid Hemorrhage From Ruptured Aneurysms at the Internal Carotid Artery-Posterior Communicating Artery Bifurcation Not Detectable on Preoperative Imaging Studies

Since subarachnoid hemorrhage (SAH) due to the re-rupture of cerebral aneurysms severely worsens the prognosis, an accurate initial diagnosis is essential. Computed tomography (CT) and magnetic resonance imaging (MRI) usually detect aneurysmal subarachnoid hemorrhage (aSAH). However, in rare cases, its identification on CT- and MRI scans is difficult, and a cerebrospinal fluid (CSF) examination is required. We present preoperative imaging and intraoperative findings in patients whose aSAH detection necessitated a CSF examination. Of 225 aSAH patients who underwent preoperative imaging studies at our institution between April 2010 and August 2019, 3 females (1.3%, mean age 57.3 years) harbored undetectable aSAH due to the rupture of an internal carotid artery-posterior communicating artery (ICA-PcomA) aneurysm. The aneurysmal orientation was inferolateral. Intraoperatively, the anterior petroclinoid ligament hampered the detection of the aneurysms that firmly adhered to the surrounding arachnoid membrane. Sustained arterial pulsation and successive minor hemorrhage can lead to the gradual adhesion of an ICA-PcomA aneurysm to the surrounding arachnoid membrane and explain their atypical rupture undetectable on imaging studies and the development of acute subdural hematoma without SAH.

Impact of branch arteries on efficacy of endoluminal flow diverters: Insights from posterior communicating artery aneurysms

BACKGROUND

Flow diverter treatment may inevitably require jailing of the branch vessels. While the patency of covered branch arteries and associated safety risks have been a topic of substantial interest, the question of whether the characteristics of branch vessels affect flow diversion's efficacy remains unanswered. In this study, we aimed to assess the impact of branch arteries on the efficacy of endoluminal flow diverters, specifically focusing on posterior communicating artery (Pcomm) aneurysms.

METHODS

Following PRISMA guidelines, we systematically searched the MEDLINE, EMBASE, Scopus, Web of Science, and Cochrane databases with predefined keywords. Studies providing data for flow diversion outcomes in Pcomm aneurysms were included. Outcomes of interest included complete and adequate aneurysm obliteration, ischemic and hemorrhagic complications, and Pcomm occlusion in the follow-up period. A random or fixed effects model was used to calculate the odds ratios (ORs) and pooled event rates with their corresponding confidence intervals (CI).

RESULTS

The overall complete and adequate aneurysm occlusion rates were 72.25% (95% CI: 64.46-78.88%) and 88.37% (95% CI: 84.33-92.6), respectively. Fetal-type Pcomm aneurysms had significantly lower complete aneurysm occlusion rates than the nonfetal-type Pcomm aneurysms (OR: 0.12, 95% CI: 0.05-0.29). Overall ischemic and hemorrhagic complication rates were 2.62% (95% CI = 0.71-5.32) and 0.71% (95% CI: 0-2.24), respectively. There were no significant associations between Pcomm morphology and complications (OR: 3.61, 95% CI = 0.42-31.06 for ischemic complications and OR: 2.31, 95% CI = 0.36-14.6 for hemorrhage). Overall Pcomm occlusion rate was 32.04% (95% CI = 19.96-47.13), and the Pcomm patency was significantly lower in nonfetal-type Pcomm aneurysms (OR: 0.10, 95% CI = 0.02-0.44).

CONCLUSION

Our meta-analysis suggests that flow diversion is a safe treatment option for Pcomm aneurysms, regardless of fetal-type Pcomm morphology. However, on the other hand, our findings indicate that Pcomm anatomy or the presence of jailed large branches can affect the efficacy of flow diverter treatment.

Treatment of an infundibular aneurysm by posterior communicating origin disconnection, induced flow reversal and flow diversion after attempted surgical clipping: Case report

Infundibular aneurysms are rare lesions that present unique challenges for both surgical and endovascular approaches. We present a case of a 58-year old man with an incidental 7.5 × 3 mm infundibular aneurysm that incorporated the origin of the posterior communicating artery (PCoA). The fusiform aneurysm incorporated the supraclinoid ICA to the terminus. An attempt at surgical clip reconstruction of the aneurysm to preserve the PCoA was not technically possible due to atherosclerosis at the aneurysm neck. The aneurysm was treated with disconnection of the PCoA origin, induced flow reversal and placement of a flow diverter, after confirmation of adequate collateral flow to the PCoA perforators from the posterior circulation. The case illustrates important concepts in the evaluation and management of infundibular aneurysms, including both reconstructive and deconstructive strategies.

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.

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.

Predictive value of neurophysiological monitoring during posterior communicating artery aneurysm clipping for postoperative neurological deficits

Objective

This study aimed to evaluate the diagnostic effect of intraoperative neurophysiological monitoring in identifying intraoperative ischemic events and predicting postoperative neurological dysfunction during PCoA aneurysm clipping, as well as to explore the safe duration of intraoperative temporary clipping of the parent artery.

Methods

All 71 patients with PCoA aneurysm underwent craniotomy and aneurysm clipping. MEP and SSEP were used for monitoring during operation to evaluate the influence of MEP/SSEP changes on postoperative neurological function. Receiver operating characteristic (ROC) curve analysis was used to calculate optimal duration of intraoperative temporary clipping.

Results

Patients with intraoperative MEP/SSEP changes were more likely to develop short-term and long-term neurological deficits than those without MEP/SSEP changes (P < 0.05). From the ROC curve analysis, the safe time from the initiation of temporary clipping during the operation to the early warning of neurophysiological monitoring was 4.5 min (AUC = 0.735, 95%CI 0.5558-0.912). Taking 4.5 min as the dividing line, the incidence of short-term and long-term neurological dysfunction in patients with temporary clipping >4.5 min was significantly higher than that in patients with temporary clipping ≤4.5 min (P = 0.015, P = 0.018).

Conclusion

Intraoperative MEP/SSEP changes are significantly associated with postoperative neurological dysfunction in patients with PCoA aneurysms. The optimal duration of temporary clipping of the parent artery during posterior communicating aneurysm clipping was 4.5 min under neurophysiological monitoring.

Selection bias in patients proposed for neurosurgical versus endovascular treatment of aneurysms of the posterior communicating artery

BACKGROUND

Microsurgical clipping and endovascular coiling are viable treatment options for posterior communicating artery (PComA) aneurysms, but there are still major limitations to evidence-based decisions regarding standard-of-care treatment. In this study, we aimed at assessing potential selection biases that may influence our ability to extract conclusions about the comparative effectiveness or efficacy of the aneurysm treatment.

OBJECTIVE

To study the patient/aneurysm characteristics as possible biases in the option for endovascular or neurosurgical treatment of PComA aneurysms.

METHODS

A single-center, retrospective cohort study was performed, including all patients with treated PComA aneurysms with neurosurgical clipping or endovascular coiling between January 2010 and January 2021. Clinical and morphological data were collected from electronic records, and statistical analysis was performed.

RESULTS

A total of 64 patients was eligible for inclusion; 24 (37.5%) patients were proposed for neurosurgical treatment, while 40 (62.5%) for endovascular treatment; 10 patients (25%) crossed over to the clipping group whereas none crossed over to the coiling side. Actual treatment analysis showed significantly higher diameters of mother vessel (t-test, p = 0.034) and aneurysm neck (Mann-Whitney, p = 0.029) in the clipping group and higher aspect and dome-to-neck ratios in the endovascular group (Mann-Whitney, p = 0.008). A significantly higher vasospasm frequency was found in the clipping group but only in the intention-to-treat analysis (Chi-square, p = 0.032).

CONCLUSION

Significant morphological differences between effective endovascular and surgical groups and differences in intention-to-treat analysis may limit the validity of a direct comparison between treatment options and suggest the presence of a possible selection bias.

Nomogram model for predicting oculomotor nerve palsy in patients with intracranial aneurysm

AIM

To explore the risk factors of oculomotor nerve palsy (ONP) in patients with intracranial aneurysm (IA) and develop a nomogram model for predicting ONP of IA patients.

METHODS

A total of 329 IA patients were included. Logistic regression analysis was applied to identify independent factors, which were then integrated into the nomogram model. The performance of the nomogram model was evaluated by calibration curve, receiver operating curve (ROC), and decision curve analysis.

RESULTS

Univariate and multivariate logistic regression analysis indicated posterior communicating artery (PCoA) aneurysm [hazard ratio (HR)=17.13, P<0.001] and aneurysm diameter (HR=1.31, P<0.001) were independent risk factors of ONP in IA patients. Based on the results of logistic regression analysis, a nomogram model for predicting the ONP in IA patients was constructed. The calibration curve indicated the nomogram had a good agreement between the predictions and observations. The nomogram showed a high predictive accuracy and discriminative ability with an area under the curve (AUC) of 0.863. The decision curve analysis showed that the nomogram was powerful in the clinical decision. PCoA aneurysm (HR=3.38, P=0.015) was identified to be the only independent risk factor for ONP severity.

CONCLUSION

PCoA aneurysm and aneurysm diameter are independent risk factors of ONP in IA patients. The nomogram established is performed reliably and accurately for predicting ONP. PCoA aneurysm is the only independent risk factor for ONP severity.

Efficacy and long-term results of endovascular embolization and surgical clipping for posterior communicating artery unruptured aneurysms complicated with oculomotor nerve palsy

to investigate the efficacy and long-term outcomes of endovascular embolization and surgical clipping for patients with posterior communicating artery unruptured aneurysms (PcomAs) concomitant with oculomotor nerve palsy (ONP). No significant (P > .05) difference existed in the age, gender, proportion of complete ONP, and size of eye fissure and pupil before treatment between 2 groups. After compared with before treatment, the eye fissure was widened significantly (P < .05) and the pupil narrowed significantly (P < .05), but no significant (P > .05) differences existed between the 2 groups. Complete ONP recovery was observed in 32 (80%) patients in the embolization group and 31 (77.5%) in the microsurgical group, partial ONP recovery occurred in 6 (15%) in the embolization group and 8 (20%) in the microsurgical group. The recovery rate was 95% in the embolization group and 97.5% in the microsurgical group, with no significant (P > .05) difference between 2 groups. The recovery rate of the ONP was significantly (P < .01) greater in the microsurgical group than that in the embolization group at follow-up of 1 month, 3 months, six and 12 months, respectively. At 18 months, the ONP recovery rate was not significantly different between 2 groups (95% vs 97.5%) Surgical clipping may have a faster effect on the recovery of oculomotor nerve palsy than endovascular embolization for patients with posterior communicating artery unruptured aneurysms complicated with oculomotor nerve palsy, but both approaches may result in a similar effect on the nerve recovery in the long run.Eighty patients treated with endovascular embolization or surgical clipping were retrospectively enrolled into the endovascular embolization group or surgical clipping and analyzed.

Internal Trapping of an Acutely Ruptured Dissecting Aneurysm of a Dominant Vertebral Artery Following Balloon Test Occlusion: A Case Report

Objective

To report a case of an acutely ruptured vertebral artery dissecting aneurysm (VADA) with a hypoplastic contralateral vertebral artery (VA) successfully treated with internal trapping following the estimation of the collateral flow from anterior circulation.

Case Presentation

A 46-year-old woman was diagnosed with subarachnoid hemorrhage and acute hydrocephalus. Ventriculostomy was performed under general anesthesia. CTA revealed a left VADA distal to the origin of the left posterior inferior cerebellar artery (PICA). The right VA was hypoplastic, and the right posterior communicating artery (Pcom) was fetal type. We performed balloon test occlusion (BTO) of the VA proximal to the origin of the left PICA and estimated sufficient collateral blood flow via the right Pcom and basilar artery (BA) to the anterior spinal artery (ASA) and the left PICA. Internal trapping of the left VADA was then performed. The angiograms after internal trapping revealed collateral flow from the right Pcom to the BA, and the hypoplastic right VA perfused the proximal BA and ASA. She recovered without any neurological deficits following antiplatelet therapy and vasospasm treatment. She was followed up for 6 years without any neurological events occurring.

Conclusion

When BTO indicates sufficient collateral flow, internal trapping could be a useful treatment for acutely ruptured VADAs on the dominant side, given a complete understanding of the angioarchitecture and the risk of vasospasm due to subarachnoid hemorrhage.

Radiologic assessment of rupture risk in small (<5 mm) posterior communicating artery aneurysms

Although previous studies have investigated the predictors of posterior communicating artery (PCoA) aneurysm rupture with clinical and radiologic parameters, the accessibility of "small PCoA aneurysms (<5 mm)" has rarely been reported. Here, we designed a study to identify the factors which are thought to be risky and prone to rupture in small PCoA aneurysms (<5 mm).A total of 114 patients diagnosed with PCoA aneurysm under 5 mm in size on digital subtraction angiography were retrospectively enrolled and divided into ruptured (n = 51) and unruptured (n = 63) groups. Clinical variables were reviewed, and 10 radiologic parameters were obtained, including maximum diameter, height, width, neck width, aspect ratio, dome-to-neck ratio, bleb formation, size ratio, presence of fetal-type PCoA, and inflow angle. Statistical analyses were conducted to compare the groups (ruptured vs unruptured) and identify the risk factors for rupture.High rupture rate of small PCoA aneurysm is noted (51/114, 44.7%). In the comparison analysis, parameters of size ratio (P = .045), aspect ratio (P = .001), and bleb formation (P = .015) were significantly different between the 2 groups. In the regression model, the aspect ratio (P = .045) and bleb formation (P = .004) were significantly associated with the rupture of aneurysm.In respect of small (<5 mm) PCoA aneurysms of our cohort, morphologic parameters of "bleb formation" and "a high aspect ratio" are present more often in ruptured aneurysms as compared to unruptured aneurysms.

Hemodynamic and Morphological Parameters of Ruptured Mirror Posterior Communicating Artery Aneurysms

Objective: Morphological and hemodynamic parameters might predict rupture of intracranial aneurysms (IAs). A practical model for the study is patients with ruptured mirror IAs in which one is ruptured and the other is unruptured. Although there have been analyses of the morphology and hemodynamics of ruptured mirror posterior communicating artery aneurysms (PComAAs), the sample sizes in these studies were small and only considered hemodynamics or morphological characters. Therefore, this study aimed to investigate the morphological and hemodynamic parameters associated with ruptured mirror PComAAs. Methods: We considered 72 patients with ruptured mirror PComAAs using computational fluid dynamics (CFDs). Ruptured mirror PComAAs were divided into ruptured and unruptured groups. Fourteen morphological and eight hemodynamic parameters were calculated and compared. Significant parameters were analyzed by the multivariate logistic regression to identify independent risk factors. Receiver operating characteristic (ROC) analysis was performed, and the area under the ROC curve (AUC) was calculated for all independent risk factors to determine the predictability and identify the optimal threshold. Results: Four hemodynamic and three morphological parameters were significantly different between ruptured and unruptured groups: normalized wall shear stress (NWSS), mean WSS, low wall shear WSS area (LSA%), size, aspect ratio (AR), size ratio (SR), and inflow angle (IA). Multivariate logistic regression analysis showed that AR, SR, NWSS, mean WSS, and LSA% were all independent factors significantly associated with PComAAs rupture. The ROC analysis for independent risk factors indicated that AR (0.751), NWSS (0.755), mean WSS (0.69), and LSA (0.778) had merely acceptable AUC values. Only SR (0.803) had a high acceptable AUC value. The threshold value of SR was 1.96. Conclusions: SR (>1.96) was the most significant parameter associated with IA rupture, whereas AR, NWSS, mean WSS, and LSA independently characterized the status of IA rupture.

Distribution of variations in anatomy of the circle of Willis: results of a cadaveric study of the Malawian population and review of literature

Introduction

the circle of Willis is an anatomical structure of clinical importance particularly in the evaluation of neurovascular diseases. Individuals show considerable variations in the anatomical configuration of the circle of Willis. A cross-sectional study was conducted to determine the distribution of morphological variations of the circle of Willis in Malawians and compare with other ethnic groups.

Methods

brains were collected from twenty-four recently deceased black Malawians during autopsy at Queen Elizabeth Central Hospital, a referral teaching hospital in Blantyre, Malawi and fixed in 10% buffered formalin. Digital images of the interpeduncular region (exposing the circle of Willis) were taken with an 18.4 megapixels camera from the base of the brain. Whole-circle and segmental parameters of the circle of Willis were assessed using the Osiris computer programme and classified based on a 22-type classification scheme.

Results

the following morphological variations were observed: hypoplasia, aplasia, asymmetry and accessory vessels. Typical circle of Willis was seen in 26% of the cases. Only six of the original twenty-two types were observed. Consistent with most previous studies, types 1, 3, 4, 6, 8 and 9 were common while types 10-22 were rare. Three variants not previously described in the original scheme (unilateral PcoA aplasia, AcoA duplication, and PcoA aplasia with contralateral PcoA hypoplasia) were observed in this study.

Conclusion

anatomical variations of the circle of Willis in Malawians seem to be distributed in similar frequencies and patterns as in other more-diverse populations. Circle of Willis variants with potential predilection for atherogenesis and aneurysm formation exist in the Malawian population. These should be considered in clinical practice.

Endovascular Treatment Using a Small Amount of Contrast Medium in a Patient with a Posterior Communicating Artery Ruptured Dissecting Aneurysm and Chronic Kidney Disease: A Case Report

Objective

We report a rare case of a patient with a ruptured posterior communicating artery (P-com A) dissecting aneurysm and chronic kidney disease (CKD) treated by endovascular embolization using a small amount of contrast medium.

Case Presentation

An 88-year-old female patient had sudden onset of headache and vomit due to subarachnoid hemorrhage. MRI revealed a ruptured dissecting aneurysm of the right P-com A. The patient had CKD of severity grade 4. Endovascular treatment was performed using only 10 mL of diluted contrast medium with injection through a microcatheter. The postoperative course was uneventful, and no deterioration of renal function occurred.

Conclusion

With minimal amount of contrast medium, endovascular treatment could be safely and effectively performed for patients with P-com A dissecting aneurysms and severe CKD.

Common origin of the anterior choroidal artery and posterior communicating artery with a concomitant aneurysm at the internal carotid artery-posterior communicating artery junction: A case report

The anterior choroidal artery (AChA) is one of the main arteries, and it can exhibit several anomalies, among which is the common origin of the AChA and posterior communicating artery (PcomA); however, this is relatively rare. In the case that the AChA originates from the PcomA, it is highly uncommon for a concomitant aneurysm to develop at the internal carotid artery (ICA)-PcomA junction. The present study reports such a case. A 58-year-old female developed a headache with nausea and vomiting. Computed tomography (CT) revealed a subarachnoid hemorrhage. CT angiography and digital subtraction angiography (DSA) revealed a right ICA-PcomA aneurysm, with the AChA arising from the proximal segment of the PcomA. The aneurysm was clipped in the hybrid operating room. DSA confirmed that the aneurysm had been clipped completely, and that the PcomA and AChA had been retained. Following surgery, the patient recovered well without any sequelae. CT angiography revealed no recurrence of the aneurysm at the 3-month follow-up. On the whole, as demonstrated by the case presented herein, when the AChA and PcomA have a common origin, the AChA and PcomA should be retained during concomitant aneurysm clipping at the ICA-PcomA to prevent severe infarction complications. Surgical clipping during hybrid surgery is a suitable choice.

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.

Geometric parameters on MRA source images to differentiate small Proximal Posterior communicating artery aneurysms from Infundibular dilation

BACKGROUND AND PURPOSE

We aimed to assess the accuracy of magnetic resonance angiography (MRA) in the differentiation of small aneurysms versus infundibular dilations (IDs) at the internal carotid artery-posterior communicating artery (ICA-PComA) junction, emphasizing the role of MRA axial source images.

METHODS

This retrospective study consisted of 83 focal arterial protrusions at ICA-PComA junction in 76 patients who underwent both MRA and digital subtraction angiography (DSA)/3-dimensional rotational angiography (3DRA). The diagnostic performance of MRA for differential diagnosis of aneurysm from ID was calculated using DSA/3DRA interpretation as the standard of reference. In addition, long-axis diameter, short-axis diameter, long-axis diameter/short-axis diameter (L/S) ratio, and angle of lesion (angle of the long-axis of lesion with respect to the x-axis) measured on MRA source images were compared between aneurysms and IDs.

RESULTS

Sensitivity, specificity, and accuracy of MRA for distinguishing aneurysms from IDs were 74.4% (57.9-87.0%) to 76.9% (60.7-88.9%), 93.2% (81.3-98.6%) to 95.5% (84.5-99.4%), and 85.5% (76.1-92.3%), respectively. Significant differences were found for the long-axis diameter (P < .001), short-axis diameter (P < .001), L/S ratio (P < .05), and angle of the lesion (P < .001) on MRA axial source images between aneurysms and IDs. The angle of the lesion had the highest discriminatory ability (area under the curve = .966 [.902-.994]) to differentiate aneurysms from IDs. An angle of lesion >60° was 89.7% (75.8-97.1%) sensitive and 100% (92.0-100.0%) specific for diagnosis of aneurysm.

CONCLUSIONS

MRA is a useful imaging modality for distinguishing between aneurysm and ID at the ICA-PComA junction. Furthermore, geometric parameters on MRA axial source images can provide added value in their differentiation.

Limitations of Flow Diverters in Posterior Communicating Artery Aneurysms

Background: Treatment of intracranial aneurysms with flow diverters (FDs) showed promising results. However, a subset of patients treated for posterior communicating artery (PComA) aneurysms has variable occlusion rates. Especially the fetal type-associated PComA aneurysms seemed to respond differently to treatment. We analyze our series of fetal type PComA aneurysms treated with a FD. The literature on this subject is reviewed. Methods: Data from patients treated with FD for all PComA aneurysms at the RadboudUMC Nijmegen were retrospectively analysed. Primary end-point was complete aneurysm occlusion at six months. Secondary end-points were clinical outcome, treatment safety, and results of secondary treatment after non-closure. The results for the fetal PComA aneurysms were compared to the literature. Results: Nineteen consecutive patients harboring 21 PComA aneurysms were treated. Three aneurysms had ipsilateral fetal type PCA (14.3%). Overall, none of the fetal type PcomA aneurysm showed complete occlusion versus 77.8% of the others (p = 0.03). Mortality and permanent morbidity rates were respectively 5.3% and 0%. Conclusions: FD treatment for PComA aneurysm with fetal type circulation seemed to be less effective compared to other types of PComA aneurysms. Flow characteristics at the PComA bifurcation are thought to be causative Alternative strategies should be considered as first line treatment.

Decompression surgery for pure arterial malformations in a 15 year old with acute, progressive visual impairment: illustrative case

BACKGROUND

The authors document the first case of pure arterial malformations (PAMs) of the posterior communicating artery (PCoA), which were successfully treated with microsurgical clipping of the main body of the PAMs. PAMs are defined as dilated, overlapping, and tortuous arteries with a coil-like appearance and/or a mass of arterial loops without any associated venous component. Although PAMs usually have a benign history and are often incidental findings, this case presented with acute progression of visual field impairment.

OBSERVATIONS

Because the patient's right optic tract was affected by the loop of PAMs of the PCoA, the authors performed microsurgical clipping of the main body of the PAMs using endoscopy, which ceased the progression of symptoms without any complications.

LESSONS

There have been several reports of PAMs receiving surgical treatment for accompanying lesions. However, in this case, the lesion to the main body of PAMs was the cause of visual field impairment and was successfully treated with microsurgical clipping.

Anatomical variations and morphometric properties of the circulus arteriosus cerebri in a cadaveric Malawian population

BACKGROUND

Knowledge of the anatomy of the circulus arteriosus cerebri (CAC) is important in understanding its role as an arterial anastomotic structure involved in collateral perfusion and equalisation of pressure, and may explain observed variations in neurovascular disease prevalences across populations. This study was aimed at understanding the anatomical configuration and morphometric properties of the CAC in Malawian population.

MATERIALS AND METHODS

Brains were collected from 24 recently-deceased black Malawian human cadavers during medico-legal autopsies. Photographs of the CACs were taken using a camera placed at a 30 cm height from the base of the brain. Whole-circle properties and segmental vessel parameters were analysed using the OSIRIS computer programme, paying attention to completeness, typicality, symmetry, and segmental vessel diameters and lengths.

RESULTS

The complete-circle configuration was found in 69.57% of the CACs. Of these, 37.5% were typical, representing an overall typicality prevalence of 26.09%. Vessel asymmetry was observed in 30.43% of cases. There were 7 cases of vessel aplasia and 12 cases of vessel hypoplasia. The posterior communicating artery (PcoA) was the most variable (with 12 variations), widest (7.67 mm) and longest (27.7 mm) vessel while the anterior communicating artery (AcoA) was the shortest (0.78 mm). Both the AcoA and the PcoA were the narrowest vessels (0.67 mm) in this study. CAC variations in Malawian populations appeared to be similar to those observed in diverse populations.

CONCLUSIONS

Anatomical variations of the CAC exist in Malawian population and should be taken into consideration in clinical practice.

Brainstem Stroke Presenting as Wake-Up Diplopia in a Patient With an Incomplete Circle of Willis

We present the case of a 65-year-old patient who suffered a wake-up brainstem stroke. The only symptom reported by the patient was double vision. Upon examination, she was found to have left internuclear ophthalmoplegia and ipsilateral downbeat nystagmus. Magnetic resonance angiography revealed a unilateral partial fetal posterior cerebral artery and unilateral posterior communicating artery hypoplasia. The patient was ineligible for intravenous thrombolysis: she evolved favorably with anti-platelet medication and was discharged after five days. We put forth a discussion on the clinical significance of these physical exams and magnetic resonance imaging findings.

A Semiquantitative Non-invasive Measurement of PcomA Patency in C57BL/6 Mice Explains Variance in Ischemic Brain Damage in Filament MCAo

Numerous studies on experimental ischemic stroke use the filament middle cerebral artery occlusion (fMCAo) model in C57BL/6 mice, but lesion sizes in this strain are highly variable. A known contributor is variation in the posterior communicating artery (PcomA) patency. We therefore aimed to provide a semiquantitative non-invasive in vivo method to routinely assess PcomA patency. We included 43 male C57BL/6 mice from four independent studies using a transient 45 min fMCAo model. Edema-corrected lesion sizes were measured by magnetic resonance (MR) imaging 24 h after reperfusion. Time-of-flight MR angiography was performed 7 days before and 24 h after fMCAo. Scores of PcomA size measured 24 h after, but not scores measured 7 days before fMCAo were negatively correlated with lesion size. Variability in PcomA patency explained 30% of the variance in our cohort (p < 0.0001, coefficient of determination r² = 0.3). In a simulation using parameters typical for experimental stroke research, the power to detect a true effect of d = 1 between two groups increased by 15% when an according covariate was included in the statistical model. We have demonstrated that in vivo measurement of PcomA size is feasible and can lead to increased accuracy in assessing the effect of treatments.

Superior ophthalmic vein thrombosis following coil embolization of posterior communicating artery aneurysm: Report of two cases

INTRODUCTION

The purpose was to present two patients with superior ophthalmic vein thrombosis following coil embolization of posterior communicating artery aneurysm, that have not been reported after this particular procedure yet.

METHODS

We present two patients with subarachnoid hemorrhage due to posterior communicating artery aneurysms, who were treated with stent-assisted coil embolization. Shortly after the procedure, both cases demonstrated painful proptosis, ophthalmoplegia, increased intraocular pressure, intraretinal hemorrhage and macular edema on the ipsilateral side, with congestion of intraorbital tissues and thickened and dilated superior ophthalmic vein in neuroimaging investigation. The occlusion was confirmed by digital subtraction angiography.

RESULTS

Patients were treated with anticoagulant agents and systemic corticosteroids immediately and then received medical treatment by an ophthalmologist for ocular complications of superior ophthalmic vein thrombosis.

CONCLUSION

Isolated superior ophthalmic vein thrombosis (SOVT) is rare, but may be associated with sight-threatening complications. After intracranial interventions on cerebral vessels, clinical features of SOVT including choroidal effusion syndrome should be investigated, and the patients should receive prompt and proper care including ophthalmic medications and systemic anticoagulants to restrict the ocular and systemic complications.

Traumatic Subarachnoid Hemorrhage Resulting from Posterior Communicating Artery Rupture

Traumatic subarachnoid hemorrhage (SAH), a common finding following head trauma, is usually a benign condition with a favorable outcome, seldom requiring surgical intervention. Unlike nontraumatic aneurysmal SAH, most cases of traumatic SAH occur in the sulci of the cerebral convexities, and only rarely arise at the base of the brain. Basal traumatic SAH can be life-threatening and is primarily associated with rupture of vertebrobasilar arteries. We herein present a rare case of basal traumatic SAH resulting from rupture of the posterior communicating artery (PCoA). A 77-year-old male was taken to the emergency department in a semicomatose state. Upon arrival at emergency room, the patient had a Glasgow coma scale (GCS) score of 6 (E1M3V2), and the neurologic examination demonstrated no focal neurologic deficit. Although the trauma history was evident from abrasions and bruising on the face and chest, brain computed tomography (CT) demonstrated basal SAH, which is typical for nontraumatic aneurysmal SAH. Subsequent digital subtraction angiography (DSA) disclosed a traumatic rupture at the mid-portion of right PCoA and ongoing extravasation of contrast media. Despite emergent trapping of the right PCoA by endovascular surgery, the patient’s clinical condition only minimally improved. The patient remained bed-ridden with stuporous mentality and persistent hydrocephalus. To the best of our knowledge, this is the first reported case of basal traumatic SAH originating from rupture of the PCoA. This case demonstrates that a meticulous vascular workup is mandatory for every patient with basal SAH, even though a trauma history is clear.

Prediction of the difficulty of proximal vascular control using 3D-CTA for the surgical clipping of internal carotid artery-posterior communicating artery aneurysms

OBJECTIVE

During surgical clipping of internal carotid artery (ICA)-posterior communicating artery (PCoA) aneurysms, proximal vascular control (PVC) is difficult to achieve in some cases because of variations in the anatomy of this type of aneurysm and its parent arteries. The authors investigated morphometric features that may be predictive for the necessity of anterior clinoidectomy (ACL) or cervical ICA exposure for PVC.

METHODS

The authors retrospectively reviewed 65 patients with an ICA-PCoA aneurysm treated with clipping during the previous 3 years. The factors considered for assessing the difficulty of attaining PVC included the following: the maximum diameter of the aneurysm; the distance between the tip of the anterior clinoid process (ACP) and the proximal aneurysmal neck; the presence of calcification at the ophthalmic segment of the ICA; and the angles between the communicating segment of the ICA and the ophthalmic segment of the ICA and a line perpendicular to the cranial base, which reflect the tortuosity of the ICA. These parameters were measured based on preoperative CTA results.

RESULTS

In a total of 21 patients (32.3%), PVC was difficult to perform with the usual pterional approach. In 6 patients, temporary artery occlusions (TAOs) were difficult to achieve because of severe atherosclerotic wall changes in the ophthalmic segment of the ICA. For 15 patients, the ACPs overhanging the ophthalmic segment of the ICA obstructed the ability to secure a space for TAO. In the 21 patients with PVC difficulty, ACL alone, cervical ICA exposure alone, and both ACL and cervical ICA exposure were conducted in 6, 8, and 7 patients, respectively. Multivariate analysis with binary logistic regression revealed that the maximum diameter of the aneurysm (p = 0.041), the distance between the proximal neck of the aneurysm and the ACP tip (p = 0.002), and calcification of the ICA ophthalmic segment (p = 0.001) were significant predictive factors for difficulties with PVC. A receiver operating characteristic curve analysis revealed that a distance between the proximal aneurysmal neck and the ACP tip of ≤ 5.4 mm was the best cutoff value for predicting the difficulty of attaining PVC (area under the curve 0.800, sensitivity 80.0%, specificity 80.0%).

CONCLUSIONS

A short distance between the proximal aneurysmal neck and the ACP tip and the presence of calcification at the ophthalmic segment of the ICA on preoperative CTA are helpful for predicting the difficulty of achieving PVC.

Imaging Classification of Internal Carotid Artery Hypoplasia Based on Distal Ophthalmic Segment Occlusion

BACKGROUND

Internal carotid artery (ICA) hypoplasia (ICAH) is rare. The classification of ICAH is largely unclear. The aim of the study is to propose a new imaging classification for ICAH based on the occlusion of the distal ophthalmic segment and discuss the clinical and radiological differences between the different types.

MATERIALS AND METHODS

This was a retrospective study of patients with congenital ICAH diagnosed at the Department of Neurology of the China-Japan Friendship Hospital between June 2011 and June 2016. The patients underwent temporal bone computed tomography (CT), brain CT, cranial magnetic resonance imaging, transcranial Doppler, and head and neck CT angiography.

RESULTS

A total of 20 ICAH patients were divided into the distal occlusion (12 cases; 60%) and nondistal occlusion (8 cases; 40%) types based on whether the distal ophthalmic segment was occluded. The frequencies of collateral circulation from the circle of Willis (P = .01) and dilated cerebrovascular lesions (P = .001) in the distal occlusion type was higher than in the nondistal occlusion type. Five (25%) patients developed adverse cerebrovascular events during followup: 3 ischemic cases were of the nondistal occlusion type, and 2 cases with subarachnoid hemorrhage were of the distal occlusion type.

CONCLUSIONS

A novel classification of ICAH was revealed based on the occlusion of the distal ophthalmic segment. The 2 types may show differences in collateral circulation patterns, coexisting cerebrovascular abnormalities, and potential clinical outcomes.

Retrograde stenting through anterior communicating artery in coil embolization of the posterior communicating artery aneurysm: contralateral approach

During coil embolization of wide-necked posterior communicating artery (PcomA) aneurysms, stent assistance is sometimes limited if PcomA is acutely angled at its origins from saccular neck. Herein, we present two instances where retrograde stenting was used for coil embolization of PcomA aneurysms. Both procedures involved a contralateral approach via anterior communicating artery (AcomA). To achieve this, the stent-delivery microcatheter was inserted retrograde from contralateral to ipsilateral internal carotid artery (ICA) across AcomA, arriving at ipsilateral PcomA. A separate microcatheter, passed through ipsilateral ICA, was then used to select the aneurysm sac for coil delivery. Coil embolization ultimately took place under protection of a horizontally placed stent extending from PcomA to terminal ICA. Each aneurysm was properly coiled and occluded, without procedural complications. This stenting technique is a reasonable option, offering a means of strategic coil embolization in wide-necked PcomA aneurysms and providing complete neck coverage through contralateral access.

De novo Aneurysm Formation on Internal Carotid Artery at Origin of Thick Posterior Communicating Artery: 7 Years after Transient Occlusion of Contralateral Internal Carotid Artery

The incidence of de novo intracranial aneurysm formation has been reported to be 0.84% per year. It is rare for de novo aneurysm formation to be observed on serial radiological examinations. A 64-year-old male with a history of right internal carotid artery (ICA) occlusion 7 years ago had subarachnoid hemorrhage (SAH) due to a ruptured left ICA aneurysm at the bifurcation of the posterior communicating artery (PComA). At the time of ICA occlusion, the left PComA was thick, about 3.0 mm in diameter, and no aneurysm was detected on radiological examinations. Thirty-eight months later, a small aneurysm was detected on the left ICA on magnetic resonance angiography (MRA). At the onset of SAH, the aneurysm was larger than that observed on the previous MRA. Left frontotemporal craniotomy was performed, and the aneurysm was clipped. A thick PComA might contribute to the development of an aneurysm at its origin due to hemodynamic stress. Persistent hemodynamic stress may cause enlargement of an aneurysm in 4 years and its subsequent rupture. In patient with a thick PComA, close observation is necessary to screen for de novo formation of a cerebral aneurysm.

Substrain- and sex-dependent differences in stroke vulnerability in C57BL/6 mice

The C57BL/6 mouse strain is represented by distinct substrains, increasingly recognized to differ genetically and phenotypically. The current study compared stroke vulnerability among C57BL/6 J (J), C57BL/6JEiJ (JEiJ), C57BL/6ByJ (ByJ), C57BL/6NCrl (NCrl), C57BL/6NJ (NJ) and C57BL/6NTac (NTac) substrains, using a model of permanent distal middle cerebral artery and common carotid artery occlusion. Mean infarct volume was nearly two-fold smaller in J, JEiJ and ByJ substrains relative to NCrl, NJ and NTac (N-lineage) mice. This identifies a previously unrecognized confound in stroke studies involving genetically modified strain comparisons if control substrain background were not rigorously matched. Mean infarct size was smaller in females of J and ByJ substrains than in the corresponding males, but there was no sex difference for NCrl and NJ mice. A higher proportion of small infarcts in J and ByJ substrains was largely responsible for both substrain- and sex-dependent differences. These could not be straightforwardly explained by variations in posterior communicating artery patency, MCA anatomy or acute penumbral blood flow deficits. Their larger and more homogeneously distributed infarcts, together with their established use as the common background for many genetically modified strains, may make N-lineage C57BL/6 substrains the preferred choice for future studies in experimental stroke.

Acute Oculomotor Nerve Palsy Caused by Compression from an Aberrant Posterior Communicating Artery

Oculomotor nerve palsy (ONP) is a rare neurological deficit associated with numerous underlying pathologies. Of these, aneurysm of the posterior communicating artery (PCOM) has been described due to the intimate association with the third cranial nerve in the basal cistern. Less described are other vascular abnormalities and their contribution to ONP. We describe a case of ONP thought to result from a PCOM aneurysm, per the associated magnetic resonance imaging (MRI) scan, yet found intraoperatively to be caused by a congenital vascular aberrancy. This is the first case, to our knowledge, of this presentation.

Functional posterior communicating artery of patients with posterior circulation ischemia using phase contrast magnetic resonance angiography

Posterior communicating artery (PCoA) in patients with posterior circulation ischemia (PCI) was quantitatively studied using phase contrast magnetic resonance angiography (PC-MRA). Fifty-one cases who received PC-MRA were included in the study, and divided into the research and control groups. The mean flow volume, mean flow velocity, minimum flow volume, maximum flow volume, minimum flow velocity and maximum flow velocity of the basal artery (BA), bilateral vertebral arteries, internal carotid arteries and functional posterior communicating artery (F-PCoA) were recorded, the peak heights of flow volume and flow velocity were calculated, and the typing of F-PCoA was analyzed, followed by statistical analysis. Fifty-two F-PCoAs were detected, and the median values of mean flow volume, mean flow velocity, cross-sectional area and lumen diameter were 20.31 ml/min, 4.01 cm/sec, 0.08 cm² and 0.16 cm, respectively. The blood flow curve of F-PCoA showed the sawtooth-like changes, and there could be either unidirectional blood flow or bidirectional blood flow in one cardiac cycle. F-PCoA was divided into the following 3 types: F-PCoA was consistent with anatomical PCoA (A-PCoA), F-PCoA was inconsistent with A-PCoA, and mixed type. In the presence of F-PCoA, both the diameter and cross-sectional area of BA were small, and the maximum flow velocity and peak height of flow volume were reduced, but there was no necessary correlation with the occurrence of PCI. Both flow volume and flow velocity of BA in the research group were reduced, and the forward posterior shunt flow of F-PCoA was increased. Hemodynamic characteristics of F-PCoA can be analyzed via PC-MRA. The forward posterior shunt flow of F-PCoA can provide references for the clinical auxiliary diagnosis.

The Impact of Variational Primary Collaterals on Cerebral Autoregulation

The influence of the anterior and posterior communicating artery (ACoA and PCoA) on dynamic cerebral autoregulation (dCA) is largely unknown. In this study, we aimed to test whether substantial differences in collateral anatomy were associated with differences in dCA in two common types of stenosis according to digital subtraction angiography (DSA): either isolated basal artery and/or bilateral vertebral arteries severe stenosis/occlusion (group 1; group 1A: with bilateral PCoAs; and group 1B: without bilateral PCoAs), or isolated unilateral internal carotid artery severe stenosis/occlusion (group 2; group 2A: without ACoA and with PCoA; group 2B: with ACoA and without PCoAs; and group 2C: without both ACoA and PCoA). The dCA was calculated by transfer function analysis (a mathematical model), and was evaluated in middle cerebral artery (MCA) and/or posterior cerebral artery (PCA). Of a total of 231 non-acute phase ischemic stroke patients who received both dCA assessment and DSA in our lab between 2014 and 2017, 51 patients met inclusion criteria based on the presence or absence of ACoA or PCoA, including 21 patients in the group 1, and 30 patients in the group 2. There were no significant differences in gender, age, and mean blood pressure between group 1A and group 1B, and among group 2A, group 2B, and group 2C. In group 1, the PCA phase difference values (autoregulatory parameter) were significantly higher in the subgroup with patent PCoAs, compared to those without. In group 2, the MCA phase difference values were higher in the subgroup with patent ACoA, compared to those without. This pilot study found that the cross-flow of the ACoA/PCoA to the affected area compensates for compromised dCA in the affected area, which suggests an important role of the ACoA/PCoA in stabilizing cerebral blood flow.

Anatomical Variability of the Posterior Communicating Artery

OBJECTIVE

Although posterior communicating artery (PCoA) is a smaller branch of the internal carotid artery, it gives the main contribution in the formation of circle of Willis (CW) by communicating with the internal carotid arterial system and the vertebro-basilar arterial system. The size of PCoA varies frequently. The present work aims to study the PCoA regarding its morphology, morphometry, and symmetry.

MATERIALS AND METHODS

This study was conducted on 170 human cadaveric brains. Brains were dissected carefully and delicately to expose all components of CW, especially PCoA. Morphological variations of PCoA were noted along with its morphometry and symmetry.

RESULTS

Morphological variations of PCoA were aplasia (3.52%), hypoplasia (25.29%), fenestration (0.58%), and persistent fetal pattern (16.47%). In the present study, we found the five different types of terminations of PCoA. Type I termination was the most common type, seen in 92.94% of cases, Type II termination was seen in 1.17%, Type III and Type IV terminations both were seen in 0.58%, and Type V was seen in 1.17%. The mean length of PCoA was 15.9 mm and 15.3 mm on the right and left sides, respectively. The mean diameter of PCoA was 2.1 mm and 1.9 mm on the right and left sides, respectively. Symmetry of PCoA was seen in 65.29% and asymmetric PCoA was seen in 34.70% of cases.

CONCLUSION

The present study provides the complete description of PCoA regarding its morphology, symmetry, and morphometry. Awareness of these anatomical variations is important in neurovascular procedures.

Ruptured posterior cerebral artery aneurysm presenting with a contralateral cranial nerve III palsy: A case report

Background:

Posterior cerebral artery aneurysms can frequently present with an ipsilateral cranial nerve III palsy.

Case Description:

We report the first case of a posterior cerebral artery aneurysm associated with a contralateral cranial nerve III palsy. A 64-year-old male presented with acute subarachnoid hemorrhage, Hunt and Hess grade 3, and a left-sided fixed and dilated pupil. Computed tomography scan showed hemorrhage, mainly within the left basal cisterns. Digital subtraction angiography revealed a right-sided P1–P2 junction aneurysm.

Conclusions:

This case demonstrates that, although the neurological exam can help pinpoint the location of a lesion, false localizing signs should be recognized.

Evaluation of an ischemic model in ischemia prone and general Mongolian gerbils by neurological symptom, injury, and sex difference

BACKGROUND

In the previous study, we established an ischemia-prone gerbil population (IG), which was selectively bred to increase the incidence of unilateral carotid arterial occlusion (UCO)-induced ischemia in Mongolian gerbils. However, if the characteristics of ischemia model in IG are the same as those in general gerbils (GG), and if the neurological symptoms are associated with the neurological insults in IG is still unclear.

METHODS

In the present study, we evaluated the UCO model in IG by analyzing neurological symptoms, neurological injury in the hippocampal CA1 region and compared with GG.

RESULTS

The data showed that the ratios of neurological symptom scores ≥ 2 in the IG and GG groups were 65.0% vs 30.0%, respectively, and were significantly different (P < .01).The neuronal damage following a UCO ischemic insult in the IG group was more severe compared to the GG group. There was a high correlation between the neurological insults' scale and the neurological symptom score in the IG and GG groups (r = .979 and .943 in the IG and GG groups, respectively). In animals with mild neurological symptom scores (2 and 3), the neuronal insults were significantly different between female and male gerbils in both IG and GG.

CONCLUSION

Our findings suggest that IG population would likely be more advantageous to establish an ischemic model.

Flow-diverter stents for endovascular management of non-fetal posterior communicating artery aneurysms-analysis on aneurysm occlusion, vessel patency, and patient outcome

Background Use of flow-diversion technology in the treatment of incidental and recanalized posterior communicating artery (PComA) aneurysms. Methods Patients treated with the Pipeline embolization device (PED) for PComA aneurysms were identified and included in our retrospective analysis. We evaluated aneurysm characteristics, modified Rankin Scale score (mRS) on admission, angiography follow-up, and patient clinical outcome at discharge, at three to nine months, and at 12-18 months. Results We included 56 patients with a mean age of 56 years. Median mRS on admission was 0. All aneurysms involved the PComA and were either new findings or found to have shown recanalization at angiography follow-up from previous coil embolization or surgical clipping. Intraprocedural device foreshortening was observed in one case requiring additional placement of a self-expanding stent. One intraprocedural aneurysm rupture occurred because of a broken distal wire. This patient had an mRS of 4 after the procedure. Three- to nine-month and 12- to 18-month follow-up angiography showed near complete or complete aneurysm occlusion in most cases. Minimal to mild intimal hyperplasia was seen in five cases at three to nine months. PComA patency over time showed 29 of 46 initially patent vessels still patent at six months. Thirteen and seven PComAs showed progressive decrease in flow at three to nine months and 12-18 months, respectively. Median mRS remained 0 for all patients at three- to nine-month and 12- to 18-month follow-up. Conclusions Our preliminary results show that flow-diversion technology is an effective and safe treatment option. Larger studies with long-term follow-up are needed to validate our promising results.

The Microsurgical Relationships between Internal Carotid-Posterior Communicating Artery Aneurysms and the Skull Base

Objective  This study aimed to review the anatomical and clinical characteristics of internal carotid-posterior communicating artery (IC-PC) aneurysms, especially those located close to the skull base. Methods  The microsurgical anatomy around the posterior communicating artery (PComA) was examined in a dry skull and five formalin-fixed human cadaveric heads. The clinical characteristics of 37 patients with 39 IC-PC aneurysms, who were treated microsurgically between April 2008 and July 2016, were retrospectively reviewed. Results  The anterior clinoid process (ACP), as well as the anterior petroclinoidal dural fold (APF), which forms part of the oculomotor triangle, are closely related to the origin of the PComA. Among the 39 IC-PC aneurysms, anterior clinoidectomy was performed on 4 (10.3%) and a partial resection of the APF was performed on 2 (5.1%). Both of these aneurysms projected inferior to the tentorium, or at least part of the aneurysm's dome was inferior to the tentorium. Conclusion  Proximally located IC-PC aneurysms have an especially close relationship with the ACP and APF. We should be familiar with the anatomical relationship between IC-PC aneurysms and the structures of the skull base to avoid hazardous complications.

Isolated massive intraventricular haemorrhage without subarachnoid haemorrhage due to rupture of a posterior communicating artery aneurysm

The classical presentation of a ruptured intracranial aneurysm is subarachnoid haemorrhage (SAH). We present a rare case of a ruptured posterior communicating artery (PcomA) aneurysm presented solely with massive intraventricular haemorrhage (IVH) in a 53-year-old female. The aneurysm was coiled successfully and the outcome of the patient was excellent.

Aerobic exercise prevents rarefaction of pial collaterals and increased stroke severity that occur with aging

Variation in extent of the brain's collateral circulation is an important determinant of variation in the severity of stroke and efficacy of revascularization therapies. However, the number and diameter of pial collateral "arterioles" decrease with aging in associated with reduced eNOS and increased oxidative stress. We tested whether exercise reduces this aging-induced rarefaction. Twelve-month-old mice were randomized to sedentary or voluntary wheel-running. At 26 months' age, permanent MCA occlusion was followed 72 h later by determination of infarct volume and vascular casting after maximal dilation. The decline in collateral number and diameter and 2.4-fold increase in infarct volume evident in 26-versus 3-month-old sedentary mice were prevented by exercise-training. In contrast, number and diameter of the posterior communicating collateral "arteries" were unaffected by aging or exercise. Interestingly, diameter of the primary intracranial arteries increased with aging. Mechanistically, genetic overexpression of eNOS inhibited age-induced collateral rarefaction, and exercise increased eNOS and SOD2 and decreased the inflammatory marker NFkB assessed in hindlimb arteries. In conclusion, exercise prevented age-induced rarefaction of pial collaterals and reduced infarct volume. Aging also promoted outward remodeling of intracranial arteries. These effects were associated with increased eNOS and reduced markers of inflammation and aging in the vascular wall.

sacrifice of posterior communication artery

We report ischemic complications related to obstruction of the posterior communicating artery (PcomA) and suggest treatment strategies according to the angiographic characteristics of the PcomA and the posterior cerebral artery (PCA). Twenty-one patients with PcomA aneurysm who had initially undergone endovascular treatment and had an identifiable PcomA occlusion on immediate or follow-up angiography were enrolled. We classified PcomA aneurysm according to the characteristics of the PcomA and PCA (P1) on baseline angiography, as follows: type I was defined as PcomA aneurysm with an absent PcomA and a normal-sized P1. Type II was defined as a hypoplastic PcomA and a normal-sized P1. Type III was defined as a normal-sized PcomA and an absent P1. Type IV was defined as a normal-sized PcomA and a hypoplastic P1. Type V was a normal-sized PcomA and a normal-sized P1. Among all cases of PcomA obstruction, 15 (71.4%) were type II PcomA aneurysms, four were type IV, one was type III, and one was type V. Ischemic events related to PcomA obstruction occurred in three cases (type II, III and VI), which included two tuberothalamic infarctions (type III and IV) and one cortical infarction in the territory of the PCA (type II). Follow-up angiographies showed flow change in the PcomA in 14 cases. It is relatively safe to sacrifice type II PcomA if necessary. However, physicians should pay attention to unexpected flow changes, such as recanalization or occlusion of the PcomA, which are possible after treatment.

Super-selective Balloon Test Occlusion of the Posterior Communicating Artery in the Treatment of a Posterior Cerebral Artery Fusiform Aneurysm: a Case Report

We report the case of a 49-year-old man with underlying hypertension who developed diplopia lasting 2 months. Magnetic resonance imaging and digital subtraction angiography showed multi-lobular unruptured aneurysms in the P2 portion of the posterior cerebral artery (PCA) migrating into the interpeduncular cistern of the midbrain. Because the shapes of the aneurysms were serpentine fusiform and the posterior communicating artery (PCoA) was the fetal type, we planned anastomosis of the occipital artery to the P4 portion of the PCA followed by endovascular obliteration of the parent artery including the aneurysms. Endovascular treatment was performed via a femoral approach one week after the anastomosis. Super-selective balloon test occlusion (BTO) of the PCoA was performed by using an occlusion balloon microcatheter before endovascular treatment. Occlusion of the proximal segment of the PCoA induced disturbance of consciousness of the patient. Occlusion of the distal segment other than the first point of the PCoA did not induce any neurological symptoms. The information from this super-selective BTO helped us to perform precise endovascular obliteration. The aneurysm was successfully obliterated, and the diplopia almost disappeared in a few months. Super-selective BTO of the PCoA might be a useful method for preventing ischemic complications due to occlusion of invisible perforators.

Association between patency of the circle of Willis and diabetes mellitus in patients with cerebral ischaemic stroke

Objective To examine patency of the cerebral anterior and posterior communicating arteries in patients with ischaemic stroke with or without diabetes mellitus. Methods This retrospective study included patients with acute ischaemic stroke treated between July 2011 and May 2016. Cerebral infarction was evaluated by magnetic resonance imaging. Anterior and posterior communicating-artery patency was determined using magnetic resonance angiography. Vessels were defined as patent or occluded. Results Out of 1 406 patients, incidence of vertebral basilar artery brain infarction and posterior cerebral artery brain infarction were significantly higher in patients with diabetes versus those without diabetes (35.5% versus 22.3% and 11.7% versus 6.8%, respectively). Among patients with posterior cerebral artery brain infarction, anterior and posterior communicating-artery patency rates were higher in patients with diabetes versus those without diabetes (66.7 versus 23.5% and 33.3% versus 5.9% [bilateral], respectively). Among patients with vertebral basilar artery infarction and posterior cerebral artery P1 segment infarction, patency rate of the anterior communicating artery was higher in patients with diabetes versus those without diabetes (55.7% versus 45.9%). Conclusion Among patients with ischaemic stroke, patency rate of the circle of Willis may be higher in patients with diabetes than those without diabetes.

Bilateral common carotid artery stenosis in normotensive rats impairs endothelium-dependent dilation of parenchymal arterioles

Chronic cerebral hypoperfusion is a risk factor for cognitive impairment. Reduced blood flow through the common carotid arteries induced by bilateral carotid artery stenosis (BCAS) is a physiologically relevant model of chronic cerebral hypoperfusion. We hypothesized that BCAS in 20-wk-old Wistar-Kyoto (WKY) rats would impair cognitive function and lead to reduced endothelium-dependent dilation and outward remodeling in the parenchymal arterioles (PAs). After 8 wk of BCAS, both short-term memory and spatial discrimination abilities were impaired. In vivo assessment of cerebrovascular reserve capacity showed a severe impairment after BCAS. PA endothelial function and structure were assessed by pressure myography. BCAS impaired endothelial function in PAs, as evidenced by reduced dilation to carbachol. Addition of nitric oxide synthase and cyclooxygenase inhibitors did not change carbachol-mediated dilation in either group. Inhibiting CYP epoxygenase, the enzyme that produces epoxyeicosatrienoic acid (EETs), a key determinant of endothelium-derived hyperpolarizing factor (EDHF)-mediated dilation, abolished dilation in PAs from Sham rats, but had no effect in PAs from BCAS rats. Expression of TRPV4 channels, a target for EETs, was decreased and maximal dilation to a TRPV4 agonist was attenuated after BCAS. Together these data suggest that EET-mediated dilation is impaired in PAs after BCAS. Thus impaired endothelium-dependent dilation in the PAs may be one of the contributing factors to the cognitive impairment observed after BCAS.

A Rare Cause of Sudden Ptosis: Posterior Communicating Artery Aneurysm

A forty-seven-year-old female patient was admitted to our clinic with sudden ptosis and diplopia without pain. She had no trauma or systemic disease history. Ptosis and mydriasis were observed in her left eye. Eye movement was restricted all directions without lateral. Isolated oculomotor nerve paralysis was diagnosed based on clinical findings, and posterior communicating artery aneurysm was observed in magnetic resonance angiography.

Traumatic posterior communicating artery-cavernous fistula, angioarchitecture, and possible pathogenesis: a case report and literature review

Carotid-cavernous fistulas (CCFs) are an abnormal vascular shunt between the carotid artery and the cavernous sinus, and were traditionally classified into four subtypes based on the detailed fistulas anatomy and arterial supply. CCFs are frequently encountered in patients with traumatic skull base fractures. In this report, we present one such case caused by two head traumas. Computed tomography and digital subtraction angiography confirmed that this CCF arose from posterior communicating artery of the internal carotid artery, which is not included in the traditional Barrow et al's categorization. The possible mechanisms include laceration of dural mater of posterior clinoid process and laceration or pseudoaneurysm formation of posterior communicating artery. This case was successfully treated with endovascular coil embolization.

Progress in treating ruptured infundibular dilatation at the origin of the intracranial posterior communicating artery

Infundibular dilatation (ID) can occur at the origin of the intracranial posterior communicating artery. When this type of widening is less than 3 mm in diameter and the ID reaches the posterior communicating artery, it can be called posterior communicating artery infundibular dilatation (Pcom-ID). Currently, Pcom-ID is considered a normal anatomic variation, and the majority of Pcom-IDs are stable. However, in some cases, rupture occurs in a Pcom-ID; furthermore, Pcom-IDs can evolve into aneurysms. There are not many studies on Pcom-ID rupture hemorrhage; therefore, we performed a retrospective evaluation of published studies on Pcom-ID rupture hemorrhage and conducted a classification analysis for this condition. It is reasonable to classify Pcom-ID into three types: Type 1, direct rupture of the Pcom-ID; Type 2, bleb rupture of Pcom-ID; and Type 3, Pcom-ID rupture caused by an aneurysm. This type of classification can provide meaningful guidance for treating ruptured Pcom-ID. In addition, the present study also included a systematic review and summarization of the literature on each type. This investigation was aimed to improve the understanding of Pcom-ID rupture hemorrhage.

Microsurgical confirmation of perforating arteries arising from the fundus of a posterior communicating artery aneurysm

Perforating arteries rarely project from the fundus of an aneurysm. We present the case of a 35-year-old woman who was found to have a right posterior communicating artery (PCOM) aneurysm via catheter angiography. Superselective microcatheter angiography revealed that perforating arteries arose from the aneurysm fundus that supplied the anterolateral thalamus. Microsurgical exploration confirmed several small perforating arteries arising from the aneurysm dome as well as an atretic distal PCOM artery. Given the complex anatomy, the lesion was unsuitable for clipping. We propose that this aneurysm represents a developmental variant whereby the proximal PCOM artery becomes atretic and terminates in PCOM perforators. The video can be found here: http://youtu.be/iDcp9fsDjq4.

Endovascular treatment of posterior communicating artery aneurysms in the presence of the fetal variant of posterior cerebral artery

Posterior communicating artery (PcomA) aneurysms in the presence of the fetal variant of posterior cerebral artery (PCA) often pose technical challenges for endovascular treatment because of a greater potential for ischemic injury with the fetal PCA compromise. The purpose of this study was to assess the feasibility and results of endovascular treatment for these lesions. We retrospectively reviewed our experience and results of endovascular treatments for a series of nine consecutive patients with PcomA aneurysms occurring at the origin of fetal PCAs at the Department of Neurosurgery of Southwest Hospital, Chongqing, China, between June 2011 and June 2014. Depending on the angiographic findings, location and shape of the aneurysms, various therapeutic strategies were used including coiling by single or double microcatheter, balloon remodeling technique, and single or Y-stenting technique. Overall, fetal PCA was preserved patent in all cases, and complete or near complete occlusion was achieved in 8/9 cases. There was no procedure-related morbidity or mortality. With the exception of one patient who died of pneumonia 6 weeks after treatment, no clinical evidence of neurologic deterioration and hemorrhagic complication was seen during the follow-up period in the remaining 8 patients. Our experience suggests that endovascular treatment is relatively safe and technically feasible in most patients with PcomA aneurysms in the presence of fetal PCA using multiple strategies.

Lateral supraorbital approach to ipsilateral PCA-P1 and ICA-PCoA aneurysms

Background:

Aneurysms of the posterior cerebral artery (PCA) are rare and often associated with anterior circulation aneurysms. The lateral supraorbital approach allows for a very fast and safe approach to the ipsilateral lesions Circle of Willis. A technical note on the successful clip occlusion of two aneurysms in the anterior and posterior Circle of Willis via this less invasive approach has not been published before. The objective of this technical note is to describe the simultaneous microsurgical clip occlusion of an ipsilateral PCA-P1 and an internal carotid artery - posterior communicating artery (ICA-PCoA) aneurysm via the lateral supraorbital approach.

Case Description:

The authors present a technical report of successful clip occlusions of ipsilateral located PCA-P1 and ICA-PCoA aneurysms. A 59-year-old female patient was diagnosed with a PCA-P1 and an ipsilateral ICA-PCoA aneurysm by computed tomography angiography (CTA) after an ischemic stroke secondary to a contralateral ICA dissection. The patient underwent microsurgical clipping after a lateral supraorbital craniotomy. The intraoperative indocyanine green (ICG) videoangiography and the postoperative CTA showed a complete occlusion of both aneurysms; the parent vessels (ICA and PCA) were patent. The patient presents postoperative no new neurologic deficit.

Conclusion:

The lateral supraorbital approach is suitable for the simultaneous microsurgical treatment of proximal anterior circulation and ipsilateral proximal PCA aneurysms. Compared to endovascular treatment, direct visual control of brainstem perforators is possible.

Endovascular repair of posterior communicating artery aneurysms, associated with oculomotor nerve palsy: A review of nerve recovery

PURPOSE

Oculomotor nerve palsy (ONP) is often the presenting symptom in patients with posterior communicating artery (PCOMM) aneurysms with variable recovery of oculomotor nerve function following treatment. In this study we report the ophthalmologic outcome of 20 patients treated by endovascular coiling for PCOMM aneurysm-induced ONP.

METHODS

We performed 230 PCOMM aneurysm endovascular coilings between the years 2006 and 2011, of which 20 cases presented with ONP. We recorded the degree of nerve recovery - complete, partial or none - while also documenting other predictive factors, such as degree of pre-intervention nerve deficit, presence of subarachnoid haemorrhage (SAH), size and location of the PCOMM aneurysm and length of follow-up.

RESULTS

Of the 20 patients, 9 (45%) presented with complete ONP and 11 (55%) with partial ONP. After an average follow-up period of 16 months, all patients achieved oculomotor nerve recovery; 9 (45%) patients had complete recovery and 11 (55%) patients had partial recovery. Of the 9 patients who presented with complete ONP, 5 (56%) patients made a complete recovery and 4 (44%) made a partial recovery. Of the 11 patients who initially presented with partial ONP, 4 (36%) made a complete recovery and 7 (64%) made a partial recovery. 7 (35%) patients also had a SAH, of whom 3 (43%) made a complete recovery with 4 (57%) making a partial recovery.

CONCLUSIONS

ONP can occur with PCOMM aneurysm with or without SAH. Endovascular coiling is an effective treatment for ONP due to PCOMM aneurysms.