Basilar Artery Fenestration Research Articles

Imaging and blood flow characteristics of cerebrovascular fenestration malformation and its relationship with the occurrence of ischemic cerebrovascular disease

ObjectiveTo explore the imaging and transcranial Doppler cerebral blood flow characteristics of cerebrovascular fenestration malformation and its relationship with the occurrence of ischemic cerebrovascular disease.MethodsA retrospective analysis was conducted on the imaging data of 194 patients with cerebrovascular fenestration malformation who visited the Heyuan People’s Hospital from July 2021 to July 2023. The location and morphology of the fenestration malformation blood vessels as well as the presence of other cerebrovascular diseases were analyzed. Transcranial Doppler cerebral blood flow detection data of patients with cerebral infarction and those with basilar artery fenestration malformation were also analyzed.ResultsA total of 194 patients with cerebral vascular fenestration malformation were found. Among the artery fenestration malformation, basilar artery fenestration was the most common, accounting for 46.08% (94/194). 61 patients (31.44%) had other vascular malformations, 97 patients (50%) had cerebral infarction, of which 30 were cerebral infarction in the fenestrated artery supply area. 28 patients with cerebral infarction in the fenestrated artery supply area received standardized antiplatelet, lipid-lowering and plaque-stabilizing medication treatment. During the follow-up period, these patients did not experience any symptoms of cerebral infarction or transient ischemic attack again. There were no differences in peak systolic flow velocity and end diastolic flow velocity, pulsatility index and resistance index between the ischemic stroke group and the no ischemic stroke group in patients with basal artery fenestration malformation (P > 0.05).ConclusionCerebrovascular fenestration malformation is most common in the basilar artery. Cerebrovascular fenestration malformation may also be associated with other cerebrovascular malformations. Standardized antiplatelet and statin lipid-lowering and plaque-stabilizing drugs are suitable for patients with cerebral infarction complicated with fenestration malformation. The relationship between cerebral blood flow changes in basilar artery fenestration malformation and the occurrence of ischemic stroke may not be significant.

Basilar Artery, Anterior Inferior Cerebellar Artery, Superior Cerebellar Artery

The basilar artery(BA)is formed by the fusion of two longitudinal arteries, and incomplete development may lead to BA fenestration. The BA provides many short perforating arteries and long lateral pontine arteries to the brain stem. The anterior inferior cerebellar artery(AICA)usually branches from the proximal third of the BA and primarily perfuses the ventral, inferior and lateral aspect of the cerebellum and inner ear organ. However, there are many variations to the AICA that depend on the degree of posterior inferior cerebellar artery development. The superior cerebellar artery(SCA)branches into not only to the rostral, ventral aspect of the cerebellar hemisphere, but also to the deeper cerebellar nucleus and brain stem. Duplications within this vessel are frequently identified, but it is not missing.

Successful treatment of a basilar artery fenestration aneurysm using a kissing flow diverter stent.

Successful treatment of a basilar artery fenestration aneurysm using a kissing flow diverter stent.

Bihemispheric Right Anterior Cerebral Artery, Fenestrated Origin of the Left Pericallosal Artery, Fenestrated Basilar Artery, Double Right Posterior Cerebral Artery.

Anatomical variations of the cerebral vasculature are frequently encountered. The archived magnetic resonance angiogram of a 62-year-old male patient was studied anatomically on planar slices and 3-dimensional volume renderings. Numerous anatomical variants were found in that single case. In the vertebrobasilar system were found: the proximal basilar artery fenestration, with a unilateral origin from that fenestration of an anterior inferior cerebellar artery, and the unilateral origin of the superior cerebellar artery from the P1 segment of the main posterior cerebral artery (PCA). There were also unilateral variants of the right internal carotid artery (ICA): a subvariant of an accessory PCA leaving the ICA as a hyperplastic anterior choroidal artery and united to the main PCA by a short communicating branch, distinctive of the posterior communicating artery in that side (unilateral double PCA); a right bihemispheric anterior cerebral artery (ACA) but with complete agenesis of the contralateral A1 ACA segment; from the right ACA continued an anatomically normal ipsilateral A2 segment and a short transverse contralateral A2 that, in turn, sent off long pericallosal and callosomarginal arteries; and fenestrated origin of the left pericallosal artery. Therefore, an arterial variant in one of the main cerebral circulations could not exclude anatomical variants in the other cerebral circulatory beds.

Extremely long posterior cerebral artery P1 segment.

Excluding aplasia and hypoplasia of the P1 segment of the posterior cerebral artery (PCA), anatomical variations in the PCA are rare. To our best knowledge, there are few reports of an extremely long P1 segment of the PCA. Herein, we report a rare case of an extremely long P1 segment of the PCA, which was diagnosed by 1.5-T magnetic resonance angiography (MRA). A 96-year-old woman was transferred by ambulance to our hospital with impaired consciousness. Her symptom improved, and magnetic resonance imaging showed no significant findings. MRA revealed an extremely long P1 segment of the left PCA. The length of the P1 segment of the left PCA was 27.3mm. The left posterior communicating artery (PCoA) was 20.9mm, which is not considered long. The left anterior choroidal artery branched from the internal carotid artery distal to the PCoA branching position. Basilar artery fenestration was also incidentally identified. Careful imaging assessment was important for identifying the extremely long P1 segment of the PCA in the present case. This rare anatomical variation can also be confirmed by 1.5-T MRA.

Retrospective analysis of image characteristics of 76 cases of cerebral vascular fenestrations.

This study aims to summarize the clinical and imaging features of cerebral vascular fenestration and to explore the association between cerebral vascular fenestration and cerebral infarction and aneurysm. The computed tomography angiography (CTA), magnetic resonance angiography (MRA), and digital subtraction angiography (DSA) imaging data of 76 cases of cerebral vascular fenestration from January 2021 and December 2021 in the Yantai Yuhuangding Hospital Affiliated to Qingdao University were analyzed. The general information was described. The location, morphology, and size of cerebral vascular fenestration were described. The association between cerebral vascular fenestration and infarction and aneurysm was analyzed. Among 76 patients, a total of 80 fenestrations were detected (two patients had three fenestrations), and basilar artery fenestration was the most common (28/80). The fenestration <5 mm was 43/80, 5-10 mm was 12/80, and ≥10 mm was 25/80. Moreover, 19 patients had other vascular diseases: 10 with aneurysms, 5 with moyamoya diseases, and 4 with cerebral artery dissections. Except for one aneurysm at the site of the fenestration, other aneurysms were separate from the fenestrations. In addition, 37 patients had cerebral infarctions, of which 16 had cerebral infarctions in the blood supply area of the arterial fenestration. Among these 16 patients, there was more cerebral infarction in posterior circulation than in anterior circulation. However, no statistically significant differences were detected in the risk factors between the fenestration-relevant cerebral infarctions group and the non-fenestration-relevant cerebral infarctions group. In our study, cerebral vascular fenestration occurred most frequently in the basilar artery and may be combined with other vascular diseases. Fenestration in posterior circulation may be related to cerebrovascular diseases. Nonetheless, no clear clinical relevance was observed between fenestration and cerebral infarction. Also, we did not find a definite association between fenestration and aneurysm. For fenestration patients with cerebral infarctions, long-term antiplatelet and statin therapy may be safe and effective.

Hemodynamic Differences Between Basilar Artery Fenestration and Normal Vertebrobasilar Artery: A Pilot Study.

Background: Basilar artery fenestration has been proposed as a contributor to ischemic stroke, as unique flow patterns induced by fenestration may be related to thrombus formation or insufficiency. This study aimed to evaluate the hemodynamics of basilar artery fenestration (BAF) using computational fluid dynamics (CFD).Methods: Patients with BAF and normal vertebrobasilar system were recruited and separately evaluated using CFD. Specific geometric vascular models were reconstructed based on 3D-rotational angiography (3D-RA). Patients were divided into the BAF group and control group (i.e., patients with the normal vertebrobasilar system). Hemodynamic and geometric variables were calculated and compared between groups using Student's t-test or Wilcoxon rank-sum test.Results: Overall, 24 patients were included, with 12 patients each in the BAF group and the control group. The BAF group had a significantly smaller basilar artery diameter than the control group (3.1 ± 0.51 vs. 3.76 ± 0.4, p = 0.002). Compared to the control group, the BAF group had higher values of maxOSI (median, 0.3 vs. 0.09, p = 0.028), TAWSSG (median, 983.42 vs. 565.39, p = 0.038) in the flow confluence, higher SAR-TAWSSG in bifurcation (median, 70.22 vs. 27.65, p = 0.002) and higher SAR-TAWSSG in basilar artery (median, 48.75 vs. 16.17, p < 0.001) of the vertebrobasilar artery.Conclusions: This pilot study suggested that hemodynamic differences between BAF and normal vertebrobasilar artery across multiple shear flow parameters. The disturbed flow in the BAF may increase the risk of thrombus formation, plaque instability, and subsequent ischemic cerebrovascular events. These should be confirmed by future studies.

Incidental Finding of a Fenestrated Vertebrobasilar Junction Aneurysm

Basilar artery fenestration is a rare anatomical variation resulting from the failed fusion of the two vertebral arteries during embryonic life. In order of frequency, it is the second most common location of vascular fenestrations after the anterior communicating artery. Vertebrobasilar junction aneurysms are uncommon but often associated with basilar artery fenestration. We report the case of a fenestrated vertebrobasilar junction saccular aneurysm in a 57-year-old woman. The diagnosis was incidentally made on CT angiography which found the anatomical variant and the aneurysm. The radiological features illustrating this association are detailed here and a brief discussion of its pathogenesis and management was made. Vertebrobasilar junction aneurysms are rare and their presence should suggest an associated basilar fenestration.

Anatomical Variability in the Origin, Length and Termination of Basilar Artery and its Clinical Implications

Introduction: Basilar artery is one of the frequent locations for cerebrovascular lesions like aneurysm, thrombosis and haemorrhage. Hence,an intricate knowledge of its variant anatomy is essential for diagnostic procedures like Computed Tomography (CT) brain and Magnetic Resonance (MR) angiography. An accurate interpretation of the arterial pattern will help in performing surgeries of brain stem precisely. Any misinterpretation of arterial pattern may affect the diagnosis, treatment and prognosis of the disease. Aim: To elucidate the anatomical variability in the origin, length and termination of basilar artery. Materials and Methods: This cross-sectional study was conducted from May 2019 to April 2020, on 100 human cadaveric brain specimens available in the Department of Anatomy at Government Medical College Pudukkottai, Tamil Nadu, India. The morphology of the basilar artery was studied with respect to the level of the origin, length, level and mode of termination of the basilar artery. Results: Among the 100 human cadaveric brain specimens dissected and examined (mean age of 63.4 years), the mean length of basilar arteries was 2.792±0.32 cm. In all 100 specimens, the basilar artery was formed by the union of right and left vertebral arteries. The basilar artery was found to originate at the level of pontomedullary junction in 84%, below the pontomedullary junction in 14% and above the pontomedullary junction in 2% of specimens. The termination of basilar artery was at the level of upper border of pons in 90%, below the upper border of pons in 7% and above in the interpeduncular fossa in 3% of specimens. The mode of termination was 'V’ shaped in 83%, 'T' shaped in 10%, trifurcation in 3%, quadrifurcation in 3% and pentafurcation in 1% of specimens. Fenestration of basilar artery was seen in 1%. Other variations of basilar artery like duplication were not detected. Conclusion: The level and mode of origin and termination of basilar artery are important with regard to surgical procedures in the lower basilar region. Variations in the basilar artery should be identified preoperatively so that neurosurgeons can modify the surgical approaches.

Multiple intracranial vessel fenestrations: A report of two cases from a tertiary care center

Intracranial vascular fenestrations are unique anatomical anomalies, consequential to developmental perturbations in vessel embryology. The importance of identification rests on its frequent association with disturbed cerebral flow dynamics and intracranial pathologies. Herein, we report two cases from the same institute of such an association. One presented with an isolated intraventricular hemorrhage, found to have basilar artery fenestrations, whereas the other presented with subarachnoid hemorrhage, with fenestrations involving both the anterior and posterior circulations. Neither of the two patients had any evidence of aneurysms, arteriovenous malformations, or dissections and were managed conservatively. Being acquainted with the anatomy and pathophysiology of these vascular aberrations are paramount in achieving optimal patient outcomes in certain vascular catastrophes.

Internal trapping for ruptured vertebral artery dissecting aneurysm proximal to the posterior inferior cerebellar artery results in infarctions associated with basilar artery fenestration

Internal trapping for ruptured vertebral artery dissecting aneurysm proximal to the posterior inferior cerebellar artery results in infarctions associated with basilar artery fenestration

A Case of Ruptured Aneurysm Arising from Basilar Artery Fenestration Accompanied by Persistent Primitive Hypoglossal Artery

A Case of Ruptured Aneurysm Arising from Basilar Artery Fenestration Accompanied by Persistent Primitive Hypoglossal Artery

Reconstructive endovascular treatment of basilar artery fenestration aneurysms: A multi-centre experience and literature review.

Data on outcome after endovascular treatment of basilar artery fenestration aneurysms (BAFAs) is limited. This study presents our multi-centre experience of BAFAs treated by different reconstructive techniques including coils, stent-assisted coiling (SAC), flow diversion and intra-saccular flow disruption with the Woven Endobridge (WEB). Retrospective analysis of 38 BAFAs treated endovascularly between 2003 and 2020. The primary endpoint was complete aneurysm obliteration defined as Raymond-Roy occlusion classification (RROC) I on immediate and follow-up (FU) angiography. The secondary endpoints were procedure-related complications, rate of re-treatment, and clinical outcome. Endovascular treatment was feasible in 36/38 aneurysms (95%). The most frequent strategy was coiling (21/36, 58%), followed by SAC (7/36, 19%), WEB embolization (6/36, 17%) and flow diversion (2/36, 6%). A successful aneurysm occlusion (defined as RROC 1 and 2) on the final angiogram was achieved in 30/36 (83%) aneurysms including all patients presenting with baseline subarachnoid haemorrhage and 25/36 (69%) were occluded completely. Complete occlusion (RROC 1) was more frequently achieved in ruptured BAFAs (15/25, 60% v. 2/11, 18%; p = 0.031). Procedure-related complications occurred in 3/36 (8%) aneurysms. Re-treatment was executed in 12/36 (33%) aneurysms. After a median angiography FU of 38 months, 30/31 (97%) BAFAs were occluded successfully and 25/31 (81%) showed complete occlusion. Reconstructive endovascular treatment of BAFAs is technically feasible with a good safety profile. Although in some cases re-treatment was necessary, a high rate of final aneurysm occlusion was achieved.

Hemodynamic effects of size and location of basilar artery fenestrations associated to pathological implications.

Fenestration is a rare congenital abnormality that refers to a segmental duplication of arteries. It is still not clear about the role of fenestrations in the etiology and pathological evolution of vascular diseases. This study aims to investigate the hemodynamic influence brought by various sizes and locations of fenestration in basilar artery models. A series presumptive fenestration models were established based on a normal basilar artery model with various sizes and locations. Identical boundary conditions were utilized in the computational fluid dynamics simulations and different flow patterns in the fenestration and bifurcation regions were comprehensively analyzed. Wall shear stress (WSS)-related parameters such as oscillatory shear index (OSI) and aneurysm formation index (AFI) were computed and compared. The value of WSS on fenestration increased by the fenestration's tortuosity, and nearly-circular fenestration suffered higher WSS than narrow-strips one. Also, high OSI and low AFI value mainly occurred in the bifurcation region, indicating a high level of turbulence and high risk of aneurysm formation. The location of fenestration mainly changed the impact force of blood flow on the bifurcation and the disorder characteristics of blood flow, while the size of fenestration changed the WSS distribution on the proximal inner wall and bifurcation region of fenestration. In summary, the nearly-circular fenestration should be stratified carefully which may results in a high risk inducing unfavorable vascular wall remodeling.

Endovascular treatment modalities for basilar artery fenestration aneurysms: experience of two centers and literature review

Background/aim The aim of this study is to present our experience on various endovascular treatment modalities of basilar fenestration aneurysms and reviewing our findings together with literature data.Materials and methods A total of 26 basilar artery fenestration (BAF) aneurysms in 24 patients were endovascularly treated in two different neurointerventional radiology clinics. All patients had been evaluated with computed tomography (CT), CT angiography, and digital subtraction angiography before the procedure. ResultsAneurysms of all patients were successfully occluded (technical success rate 100%). Procedure-related complications were seen in two patients. Our comprehensive literature research revealed that studies related with the topic are composed mostly of case reports. In the literature, a total of 113 BAF aneurysms of 101 patients had been treated endovascularly in 46 studies between 1993 and 2019. Success rate of the treatment was reported as 97%, clinical success rate as 91%, and complication rate as 8.8%, while these rates are 100%, 92%, and 7.6% in our study, respectively.ConclusionAlthough the number of cases is low in our study, to our knowledge, it is the widest series in the literature until today. Our results demonstrate that BAF aneurysms can be treated successfully and safely with different endovascular techniques, with more stent use in recent years.

Ruptured Bilobed Basilar Artery Fenestration Aneurysm Treated with a WEB Device.

To describe the technique of using a Woven Endo Bridge (WEB) device to treat a ruptured bilobed blister-like aneurysm (BLA) at the basilar artery (BA) fenestration. A previously healthy 66-year-old female presented at the emergency room with subarachnoid hemorrhage (SAH), centered around the brainstem. Unenhanced CT and CT angiography showed a BLA of a basilar fenestration limb. The angiogram confirmed the diagnosis. A WEB device was chosen to treat this rare and challenging aneurysm. In this article, we describe the successful endovascular treatment of a SAH patient with a ruptured BLA at the basilar artery fenestration using a WEB device. And an overview of treatment options is provided.

Double adjacent basilar artery fenestration with cerebellar infarct: Case report and new classification of double basilar fenestrations

Basilar artery (BA) fenestration is an uncommon congenital variant associated with aneurysms and posterior circulation infarcts. We present a 42-year-old male, smoker and hypertensive who came with acute onset vertigo and gait ataxia. Cerebellar signs were positive on the left side. Diffusion-weighted brain magnetic resonance imaging showed acute infarct in the left anterior inferior cerebellar artery (AICA) territory. Computed tomography angiography showed BA double adjacent fenestration of proximal segment of BA, without thrombus, dissection/aneurysm. To the best of our knowledge, only three cases of double adjacent BA fenestration have been described so far. The association between vertebro-BA fenestrations and posterior circulation stroke is controversial. It has been suggested that turbulent flow at the site of fenestration predisposes to thrombus formation, which may be cause of stroke. This rare anatomic variant of the posterior circulation is important to recognize and may have associated neurologic consequences (double BA fenestrations are rare yet known congenital variants associated with aneurysms and associated neurological implications) (double adjacent BA fenestration presenting with AICA infarct are still rarer with only three cases reported across the world).

Surgical treatment of vertebral artery confluence aneurysms

Aneurysms of vertebral artery confluence and proximal parts of basilar artery are extremely rare. They are usually combined with proximal fenestration of basilar artery. No timely surgical treatment of these aneurysms is associated with high risk of adverse outcomes, and their treatment is a challenge for neurosurgeons. We analyzed postoperative outcomes in 17 patients with 21 aneurysms of vertebral artery confluence and proximal parts of basilar artery. Six patients with 10 aneurysms underwent microsurgical resection, 11 patients with 11 aneurysms - endovascular procedure. Persistent postoperative deterioration was observed in 5 (29.4%) patients: severe neurological symptoms (GOS grade 3) in 1 case (5.9%), minor bulbar disorders in 4 cases (23.53%). There were no lethal outcomes. According to our own and literature data, aneurysms of vertebral artery confluence are extremely rare. The risk of rupture of these aneurysms is extremely high. Endovascular approach is preferred in these patients. Microsurgical procedure is an acceptable alternative if endovascular surgery is impossible.

Basilar artery fenestration aneurysm treated with the Woven EndoBridge device

Arterial fenestrations are anomalies in embryonic vascular development and considered rare congenital variations. The management of fenestration aneurysms of the lower third of the basilar artery is challenging because of complex morphology. Given its relationship with the skull base and critical neurovascular structures, endovascular treatment is preferred over microsurgery, and allows the use of a range of different endovascular devices and techniques. The Woven EndoBridge (WEB) device was specifically developed for treating wide-neck aneurysms in arterial bifurcations and is a self-expanding braided mesh of nitinol with platinum core. The devicés dense metal mesh disrupts intra-aneurysmal blood flow and promotes intrassacular thrombosis, while the mesh and neck together create a surface favorable to neo-endothelialization. The WEB allows solely endosaccular treatment, without the need for further implants in the lumen of parent vessels, thereby reducing the risk of complications and dispensing with the need for antiplatelet therapy. The present study reports the successful treatment of a basilar artery fenestration aneurysm using the WEB device.

International abstracts

Basilar artery fenestration is the second most commonly observed fenestration of the cerebral arteries. In addition to our case, we reviewed the clinical, imaging findings, treatment, and prognosis of 9 other reported cases. Patients’ mean age was 45.1 years. Half of them had cardiovascular risk factors. Mean time to diagnosis was 9.4 days. The main symptoms were right hemiparesis and dysarthria. Basilar artery fenestration was found in all patients, as well as ours, in addition to a thrombus, found in 2 cases. One patient was treated by IV thrombolysis and thrombectomy. In other cases, antiplatelet drugs or anticoagulants were used. A favorable outcome was observed in most cases with one reported death.