Fenestration Of Vertebral Artery Research Articles

Vertebrobasilar system variations; Analysis with multi-detector CT angiography

Objective: The vertebrobasilar system provides vascular nutrition to the posterior part of the brain, medulla spinalis, medulla oblongata, and cerebellum. Anatomical variations in these vascular structures increase the incidence of thrombus and aneurysms in patients. This study examines the presence of anatomical anomalies in the vertebrobasilar system. Material and Methods: Retrospective CT angiogram images of 93 adult cases over 18 years of age who were examined for any reason in KSU, Training and Research Hospital Radiology Unit. Results: Vertebral artery hypoplasia was observed in 15% of the cases. Left dominance was observed in 64.2% of the cases, right dominance in 28.6%, and co-dominance in 7.2%. Vertebral artery duplication was not observed. Vertebral artery fenestration was observed in 2.1% of cases. Vertebral artery of flexible origin was detected in 7.5%. In 57% of cases with a variable origin, the vertebral artery originated as the second branch of the subclavian artery. The right vertebral artery originating from the brachiocephalic artery was seen in 14.2%, the left vertebral artery originating from the arcus aorta was seen in 14.2%, and the left aberrant vertebral artery was seen in 14.2%. Fenestration of the basilar artery was observed in 2.1%, and hypoplasia of the basilar artery in 1.1%. Fetal type PCA variation was observed in 35.4% of cases, bilateral fetal PCA in 3.2%, right fetal PCA in 17.2%, and left fetal PCA in 15%. PCA duplication was observed in 3.2%, SCA duplication in 16.1%, unpaired single SCA in 2.1%, and SCA fenestration in 1.1%. An unpaired single AICA was observed in 15%, duplication of AICA in 2.1%, hypoplastic AICA in 6.4%, and AICA originating from SCA in 1.1%. An unpaired single PICA was observed in 12.9%, hypoplastic PICA in 2.1%, basilar artery originating PICA in 9.6%, AICA originating PICA in 4.3%, and PICA duplication in 1.1%. Conclusion: This study provides a detailed analysis of anatomical variations in the vertebrobasilar system using multi-detector CT angiography. The findings highlight the prevalence and diversity of these variations, such as vertebral artery hypoplasia, dominance patterns, fenestrations, and origin variations. These variations have significant clinical implications, particularly in the context of interventional and surgical procedures, as well as in the diagnosis and management of cerebrovascular diseases. Recognizing and understanding these anatomical differences can aid clinicians in planning more effective treatment strategies, potentially reducing the risk of complications associated with thrombus and aneurysm formation. Further research with larger and more diverse populations is recommended to validate these findings and to explore the impact of these variations on clinical outcomes. Ultimately, this study contributes to the existing body of knowledge and underscores the importance of personalized approaches in the management of vertebrobasilar system anomalies.

Early and midterm outcomes of in situ fenestration via adjustable puncture needle for Ankura aortic stent graft: A single-center experience.

An analysis was conducted to demonstrate early and midterm outcomes of using adjustable puncture needle-based in situ fenestration (ISF) technique for Ankura aortic stent graft to reconstruct the supra-arch branch in thoracic endovascular aortic repair (TEVAR). A retrospective analysis of 68 cases of aortic lesions with insufficient proximal anchoring area admitted to our department from March 2017 to December 2021 was performed. In situ fenestration thoracic endovascular repair (TEVAR) was performed at the same time during the operation. Among them, there were fifty-eight cases of thoracic aortic dissection, seven cases of thoracic aortic aneurysm, and three cases of thoracic aortic ulcer. Intraoperative adjustable puncture with needle was used for the Ankura aorta stent graft to perform ISF and reconstruction of the supra-arch branch. The success rate of ISF was 94.1% (64/68). Only in four cases, attempts were made to create ISF in the left subclavian artery (LSA), and all the four were unsuccessful because of sharp and tortuosity angle. Among them, forty-four cases were only LSA fenestration, and one case was left common carotid artery (LCCA) fenestration + LSA embolism. LSA + left vertebral artery (LVA) fenestration was performed in two cases, LSA fenestration +LCCA chimney was performed in fourteen cases, LCCA + LSA fenestration + innominate artery (INA) chimney was performed in one case, and LCCA fenestration + INA chimney + LSA embolism was performed in two cases. The overall neurologic event rate was 3.1% (spinal cord ischemia 0, with stroke observed in two cases). Postoperatively, one patient (1.6%) died on the third day after TEVAR due to the retrograde dissections. There were four cases of endoleak (6.3%; three type I and one type II). The average follow-up was 29.2 ± 14.4months, and no patient died during the follow-up period. Three cases of endoleak disappeared, and one case did not increase further. In addition, other two cases of retrograde dissections were observed at 3 and 5months after TEVAR. Fortunately, they were scheduled for emergency surgery with ascending aorta replacement and improved well. There was only one case of LSA occlusion after ISF which was reconstructed by endovascular treatment. Two patients were found with distal stent graft-induced new entries (dSINE), and TEVAR was performed again during the follow-up period. Early and midterm outcomes demonstrated that ISF via the adjustable puncture needle device for the Ankura aorta stent graft is a feasible and effective treatment method, which can achieve high technical success and satisfactory short-term results.

Differential diagnosis of vertebral artery fenestration and dissection: case report

Arterial fenestration is a rare anatomical variant characterised by the presence of a congenital segmental duplication of an artery. In certain imaging modalities it may resemble arterial dissection, which, unlike arterial fenestration, is potentially lethal and requires treatment. The use of diagnostic methods that ensure a comprehensive visualisation of the vascular system, such as computed tomography angiography (CTA), may complete inconclusive results of exams performed with other modalities and enable the differential diagnosis of arterial fenestration and dissection.

Acute Cerebral Infarction of Posterior Circulation in a Patient with Vertebral Artery Fenestration Deformity: A Case Report

Acute Cerebral Infarction of Posterior Circulation in a Patient with Vertebral Artery Fenestration Deformity: A Case Report

Dissection of both limbs of a fenestrated vertebral artery: Case report and review of literatures

AbstractBackgroundDissection of a fenestration of the vertebral artery is extremely rare.CASE REPORTSA 55‐year‐old man presented with severe headache. Radiological examinations revealed a fenestration of the intracranial vertebral artery, and both limbs of the fenestration showed stenosis and dilatation. Three‐dimensional‐T1 fat suppression‐weighted images of magnetic resonance imaging (MRI) showed an intramural thrombus. These findings indicated that dissection occurred in both limbs of the fenestrated vertebral artery. Since no hemorrhage or infarction was observed, the patient was conservatively treated with an anti‐hypertensive drug. His symptom gradually improved and finally disappeared. Follow‐up MRI in the 2nd month showed a decreased intramural thrombus and smoothened vertebral artery.DiscussionDetection of an intramural thrombus on MRI is useful for the diagnosis of dissection of a vertebral artery fenestration. Treatment of this rare condition might be the same as that for a non‐fenestrated vertebral artery.

A case of multiple Vertebrobasilar artery fenestration misdiagnosed as vertebral artery dissection

BackgroundFenestration of vertebra-basilar artery is an uncommon congenital vascular anomaly, which is identified by incidental findings on imaging in patients presented without related symptoms or in patients with intracerebral hemorrhage secondary to concomitant artery aneurysm or arteriovenous malformations. Yet, cases of fenestration being misdiagnosed as cerebral artery dissection have never been reported.Case presentationWe present a patient of 66-year-old female with acute onset of dizziness after chiropractic manipulation of the neck. Neck computed tomography angiography (CTA) showed ‘double lumen’ sign and ‘intimal flap’ of the V1 segment of the vertebral artery, which led to the initial diagnosis of vertebral artery dissection (VAD). However, vertebral artery fenestration at V1 segment was eventually identified by multi-directional digital subtraction angiography (DSA). Interestingly, concomitant vertebral fenestration at V3 segment, basilar fenestration and basilar artery tip aneurysm was also revealed by DSA.ConclusionThe triple fenestration at vertebrobasilar artery with basilar tip artery aneurysm is extremely rare, and the fenestration at the V1 segment of vertebral artery was easily misdiagnosed as VAD due to the similar imaging morphology.

Imaging features of vertebral artery fenestration.

Vertebral artery fenestration (VAF) is a rare congenital vascular anomaly which has been associated with intracranial aneurysm. VAF can share some similar imaging features with vertebral artery dissection (VAD), which may confound diagnosis of the latter on CT and MR angiography. The purpose of this investigation is to assess the prevalence of VAF, evaluate its association with other vascular anomalies, and identify imaging features to help in distinguishing VAF and VAD. Using keyword search on CTA and MRA head and neck imaging reports from 2010 to 2017, cases of VAF and VAD were retrospectively identified and imaging was reviewed. Imaging features including laterality; vertebral segment; length of affected segment; presence, number, and caliber of lumen(s); and presence of other vascular abnormalities were recorded for all cases and subsequently compared using Pearson's chi-squared test to assess for significant differences between the groups. Patient age, gender, and clinical presentations were also recorded. Of 64,888 CT and MR angiographic examinations performed, VAF was identified in 67 (0.1%) and VAD in 54 (0.1%) patients. Compared with VADs, VAFs were shorter in length (p< 0.001), wider in luminal diameter (p< 0.001), more likely to occur at the V4 segment (p< 0.01), more likely to have two distinct lumens rather than one (p< 0.01), and less likely to present post-trauma (p< 0.01). Coexisting intracranial aneurysms were identified in 9% of patients with VAF. VAFs, although rare, can be readily distinguished from VADs on angiographic imaging. Diagnosis of VAF should prompt review for intracranial aneurysm.

Nonaneurysmal cerebrovascular conditions associated with intracranial arterial fenestrations

Background: Cerebral arteries have been identified with multiple anatomical variations, including a concomitant fenestration with aneurysms, but no association is proven. Aim: to investigate non aneurysmal disorders associated with intracranial arterial fenestration. Methods: A thorough and detailed analysis of the available literature from 1970 to 2020 in PubMed were contemplated to identify and address all the disorders associated with arterial fenestration with exclusion of intracranial aneurysms. Results: While segmental vulnerability may induce invisible anatomical histological and hemodynamic changes, cadaveric studies showed that the frequency of fenestration is up to 40% higher than the clinical reports, and the cadaveric reports also showed a higher occurrence of such fenestrations as compared to radiological studies. The vertebrobasilar system, the most common site of fenestration. Fused vertebrae and other vascular defects of up to 7% are previously associated with the vertebral artery fenestration. Conclusion: intracranial fenestration is a critical anatomical variant. Thus, A comprehensive angiographical examination can enhance overall prognosis in presurgical planning in association with other vascular abnormalities.

FENESTRATION OF THE VERTEBRAL ARTERY PRESENTED BY CT ANGIOGRAPHY OF THE NECK'S BLOOD VESSELLS: CASE STUDY

Vertebral artery fenestration is a rare vascular anomaly. It most commonly occurs in extracranial segments of the vertebral artery. This congenital anomaly can occur during the various stages of embryonic development of the vertebral artery. This usually does not have clinical significance, but the possibility of associated anomalies such as saccular aneurysms and arteriovenous malformations should be noted. Awareness of vascular anomalies is key to avoiding iatrogenic injury during endovascular diagnostic and therapeutic interventions. Here, we present incidental findings of vertebral artery fenestration in a 46-year-old woman evidenced by CT angiography of the neck's blood vessells after I .V. contrast medium applications.

Posterior inferior cerebellar artery with an extradural origin from the V3 segment: higher incidence on the nondominant vertebral artery.

OBJECTIVE The posterior inferior cerebellar artery (PICA) and the vertebral artery (VA) often exhibit anatomical variations at the craniovertebral junction (CVJ). An example of this is the PICA originating extradurally from the V3 segment of the VA. To date, some cadaveric investigations have been reported, but the incidence and relationship of this variation to the VA and the atlas as observed on clinical imaging have not been discussed. This study evaluated the prevalence of PICAs originating from the V3 on CT scanning. Other variations of the atlas and VA were also analyzed. METHODS CT images from a series of 153 patients who underwent 3D CT angiography (CTA) were analyzed, and variations of the PICA, VA, and atlas were investigated. RESULTS A total of 142 patients (284 sides) were analyzed; 11 patients (7.2%) were excluded due to poor image quality. The most common VA variation was the PICA originating from V3 (9.5% of 284 sides), which was more frequently observed on the nondominant VA than the dominant VA (22.5% vs 6.25%, p = 0.0005). A VA with a PICA end was identified in 4 sides (1.4%), which is the same incidence as observed in the persistent first intersegmental VA (1.4%). VA fenestration was only found in 1 side (0.35%). Regarding the atlas, ponticulus posticus was observed in 24 sides (8.5%). There was no relationship between the incidence of ponticulus posticus and the variations of the VA. CONCLUSIONS A PICA originating from V3 was the most common VA variation at the CVJ and was more common on the nondominant VA. Three-dimensional CTA is useful for the evaluation of this variance. Surgeons should be mindful of this variation during operations.

Understanding the Course of Vertebral Artery at Craniovertebral Junction in Occipital Assimilation of Atlas: Made Simplified Using Conventional Angiography.

Introduction Preoperative assessment of vertebral artery (VA) is important to avoid its injury during surgery at craniovertebral junction (CVJ). The main concern is the course of third segment of VA (V3) while performing instrumentation at CVJ, that is, segment of VA from its course through transverse foramen of C2 to its course along the posterior arch of C1. This segment of VA includes its passage through C1 transverse foramen as well. This observational study was done to analyze the course, curvature, and termination of VA in patients with occipital assimilation of atlas at CVJ, a complex congenital anomaly, and compared with the normal course for better understanding especially by young neurosurgeons and spine surgeons. Materials and Method This is an observational study that included patients with occipitalized C1 with or without associated anomalies. Out of 30 patients of CVJ anomalies, 16 patients had occipitalized atlas. Digital subtraction angiography was done in all cases. It was done by selectively catheterizing the VA using standard Seldinger's technique and both anteroposterior and lateral projections were taken. Results The course of VA was not identical on either side in any individual. It was lengthened and tortuous in all patients. Different types of anomalous course were encountered like bypassing transverse foramen of C1, close relation with C1-2 facet joints, variable course along the posterior arch of C1, abnormal termination and fenestration of VA. Conclusion Craniovertebral junction anomalies are not only bony or neural, but are vascular too. Complex CVJ anomalies are associated with higher incidence of anomalous course of the VA, an important surgical consideration.

Management strategy for bilateral complex vertebral artery aneurysms.

Bilateral complex vertebral artery aneurysms (BCoVAAns) have no established strategy of management. We retrospectively reviewed five consecutive patients with unruptured BCoVAAns between January 2006 and December 2012. Considering surgical risks of lower cranial nerve (LCN) injuries and eventual growth of an opposite side lesion after unilateral vertebral artery (VA) occlusion, we proposed a strategy of combined open and interventional treatment using revascularization. We applied the following several specific techniques: (1) proximal clipping and occipital artery-posterior inferior cerebellar artery (OA-PICA) and/or superficial temporary artery (STA)-superior cerebellar artery (SCA) bypasses; (2) Distal blood pressure, motor evoked potentials (MEPs), and somatosensory evoked potentials (SEPs) monitoring after parent artery temporary occlusion for safe permanent occlusion of the proximal portions of VA and PICA; (3) V3 to V4 bypass using radial artery (RA) graft with proximal clipping or trapping, two of them combined with OA-PICA bypass; (4) VA fenestration as an opportunity to preserve the flow of the parent artery. Two patients were treated bilaterally and 3 unilaterally, with modified Rankin scale assessed at 39 months postoperatively in average 0 in 2, 1 in 2, and 2 in 1, respectively, and the untreated opposite side lesions without regrowth or bleeding. Two patients with patent V3-RA-V4 bypass complained of dysphagia due to LCN palsies. One of them however suffered a cerebellar infarction due to occlusion of the OA-PICA bypass. When BCoVAAns require surgical treatment, revascularization or preservation of the VA should be considered at the first operation. By doing so, the opposite aneurysm can be effectively occluded by coil embolization, even with VA sacrifice if required.

Abstract W P81: Intracranial Aneurysms and Their Relationship to Circle of Willis Variations: A Retrospective Analysis of Patients in a University Hospital

Background: Cerebral aneurysms, their rupture and resultant neurological sequelae are a major cause of morbidity and mortality. Multiple studies have analyzed the etiology of cerebral aneurysms including hemodynamic and congenital factors. Since the arterial supply of the brain develops entirely from the third pharyngeal arch and the dorsal aorta, any insult to the developing vascular system increases the probability of development of variations, including aneurysms. Purpose: To identify the association of arterial variations with aneurysms. Methods: A total of 83 patients with 106 intracranial aneurysms diagnosed by cerebral angiography from January 2011 to July 2014 were analyzed for variations in the intracranial vasculature. The type and laterality of the vascular variants in relation to the aneurysms were also examined. Results: On evaluation of the aneurysms, 65 (61.3 %) had associated variations in the intracranial vasculature. Among these, 51 (78.5 %) had variations ipsilateral to the aneurysm. 90 (84.9%) were in the anterior circulation. 52 patients (62.7%) were female. Various vascular variations including hypoplasia of posterior communicating (P-Comm) artery (56.5 %), variant anterior cerebral (ACA) artery (17.39%), fetal type posterior cerebral (PCA) artery (21.7%), fenestration of vertebral artery (1.4%), superior cerebellar artery duplication (1.4%) and arteriovenous malformations were noted. Fetal type PCAs were significantly more common in patients with anterior communicating (A-comm) (p-value &lt;0.0115) and P-Comm A aneurysms (p-value &lt;0.0131). Also, variations of A1 segment of ACA were significantly more common in A-Comm aneurysms (p-value &lt;0.0013). Conclusions: The distribution of aneurysms in the intracranial vasculature in our study is comparable to previous literature. Among the arterial variations we found that fetal type PCAs are significantly common among A-Comm and P-Comm aneurysms. Also, variations in the A1 segment of ACAs were commonly associated with A-Comm aneurysms. Although further conformation of these associations is required with a prospective randomized control trial, if established, screening for these variations could help in primary prevention and early treatment of these aneurysms.

Bow Hunter’s Stroke Due to Stretching of the Vertebral Artery Fenestration: A Case Report

Bow Hunter’s syndrome is an unusual symptomatic vertebrobasilar insufficiency resulting from intermittent mechanical compression of the vertebral artery, and is rarely a trigger for cerebral infarction following thrombus formation on the damaged endothelial vessels (Bow Hunter’s stroke). The authors present an extremely rare case of a 45-year-old man showing Bow Hunter’s stroke due to congenital vertebral artery fenestration stretching and sliding between C1 and C2 after head rotation to the right. Congenital vertebral artery anomaly rarely causes cerebral infarction, but could cause embolic strokes by mechanical stretching without bony abnormalities.

Operative nuances to safeguard anomalous vertebral artery without compromising the surgery for congenital atlantoaxial dislocation: untying a tough knot between vessel and bone

Stabilization of the craniovertebral junction (CVJ) by using lateral masses requires extensive dissection. The vertebral artery (VA) is commonly anomalous in patients with congenital CVJ anomaly. Such a vessel is likely to be injured during dissection or screw placement. In this study the authors discuss the importance of preoperative evaluation and certain intraoperative steps that reduce the chances of injury to such vessels. A 3D CT angiogram was obtained in 15 consecutive patients undergoing surgery for congenital atlantoaxial dislocation. The course of the VA and its relationship to the C1-2 facets was studied in these patients. The anomalous VA was exposed intraoperatively, facet surfaces were drilled in all, and the screws were placed according to the disposition of the vessel. A skeletal anomaly was found in all 10 patients who had an anomalous VA. Four types of variations were noted: 1) the first intersegmental artery in 5 patients (bilateral in 1); 2) fenestration of VA in 1 patient; 3) anomalous posterior inferior cerebellar artery crossing the C1-2 joint in 1 patient; and 4) medial loop of VA in 5 patients. The anomalous vessel was dissected and the facet surfaces were drilled in all. The C-1 lateral mass screw was placed under vision, taking care not to compromise the anomalous vessel, although occipital screws or sublaminar wires were used in the initial cases. A medial loop of the VA necessitated placement of transpedicular or C-2 lateral mass screws instead of pars interarticularis screws. The anomalous vessel was injured in none. Preoperative 3D CT angiography is a highly useful method of imaging the artery in patients with CVJ anomaly. It helps in identifying the anomalous VA or its branch and its relationship to the C1-2 facets. The normal side should be surgically treated and distracted first because this helps in opening the abnormal side, aiding in dissection. In the posterior approach the C-2 nerve root is always encountered before the anomalous vessel. The defined vascular anatomy helps in choosing the type of screw. The vessel should be mobilized so as to aid the drilling of facets and the placement of screws and spacers under vision, avoiding its injury (direct or indirect) or compression. With these steps, C1-2 (short segment) rigid fusion can be achieved despite the presence of anomalous VA.

Fenestration and duplication of the vertebral artery

The vertebral artery (VA) acts as a foundation for the posterior circulation of the head and neck. It presents a number of anomalies that can be easily visualized thanks to modern imaging techniques, such as MR and CT angiography or color Doppler ulrasonography. Determining the appropriate terminology for those anomalies can be sometimes more challenging than their recognition. One particular challenge concerns the differentiation between VA fenestration and duplication. Because of the different clinical prognoses associated with those anomalies, confusion should be avoided. Knowledge of the morphological anomalies associated with the VA is important for both radiologists and head and neck surgeons, because any injury to the VA can result in a threat to the vascular supply of the brain stem, the cerebral or cerebellar hemispheres, the thalamus, cervical nerve roots and particularly the lateral medulla (Wallenberg's syndrome). This article analyses world literature concerning the issue of VA fenestration and duplication to facilitate a differential diagnosis.

Azygos anterior cerebral artery aneurysm with concomittant vascular anomaly: Case report

A 51-year-old man presented with subarachnoid haemorrhage with mild hydrocephaly. Digital substraction angiography and 3-D Computerised Angiogram (CT) revealed a saccular aneurysm at bifurcation of azygos anterior cerebral artery (ACA) and other vascular variations such as vertebral artery fenestration and hypoplasia in one anterior cerebral artery. We performed aneurysmal neck clipping with good outcome and postoperative 3-D CT angiogram showed complet obliteration of aneurysm. Although azygos arteries are rare in healthy population, aneurysms of azygos ASA are not rare due to increased haemodynamic stress. We wanted to point out to better visualisation of anatomical variations at 3-D CT angiogram comparing DSA in patients with intracranial aneurysm.

頭蓋内椎骨動脈の窓形成に伴う未破裂嚢状脳動脈瘤に対し血管内治療を行った1例

【目的】未破裂で発見された頭蓋内椎骨動脈の窓形成に伴う脳動脈瘤に対して，破裂予防を目的としたコイル塞栓術を行った症例を経験したので報告する．【症例】症例は70歳女性．近医脳神経外科で偶然に左椎骨動脈V4の未破裂脳動脈瘤を指摘された．3年間フォローアップされたが，増大傾向であったために当科に紹介された．3D-DSAでは椎骨動脈にfenestrationを認め，その近位端に動脈瘤のネックが位置していた．椎骨動脈窓形成部脳動脈瘤と診断した．これに対してバルーンアシスト下にコイル塞栓術を行った（volume embolization ratio 23.8%）．【結語】椎骨動脈の窓形成を伴う脳動脈瘤は，原因となる窓形成部の同定が困難で，高空間分解能のモダリティーが必要である．また，自然歴が不明で，治療を慎重に検討すべきである．

Review of vertebral artery fenestration and novel extracranial fenestration

Although anomalies of the vasculature of the head and neck are ot particularly common, vertebral artery abnormalities have been ell described in the literature. Anatomical variations of the verebral arteries can pose significant risk for vascular injury during urgical and endovascular interventions [1]. Therefore it is imporant to understand and recognize these anomalies. The classic anatomic course of the vertebral artery has its oriin from the subclavian or innominate artery, enters the foramen ransversarium of C6–C2 where it courses around C1 to enter the oramen magnum and join the contralateral vertebral forming the asilar artery. There are some important variations of the usual natomy. The vertebral artery enters at the C6 foramen in 93% of atients; alternatively, the vertebral artery may enter at C4, C5, or 7 at the respective frequency of 1, 5, and 0.8% [1]. An aberrant verebral artery course may lead to iatrogenic injury during surgical pproaches to the cervical spine. Understandably, it has been proosed that the course of the vertebral artery should be noted in the nterpretation of all routine cervical spine MRIs. In addition to an berrant arterial route, various authors have previously described everal anomalous origins. The vessel itself may randomly divide nd reconstitute as seen in arterial fenestrations and duplications.

Detection of cerebral artery fenestrations by computed tomography angiography

Background and purposeCerebral artery fenestrations (CAF) are rare congenital variations usually diagnosed by digital subtraction angiography (DSA). The aim of this study was to examine the frequency of occurrence of fenestrations in cerebral arteries and their coexistence with cerebral aneurysms in computed tomography angiography (CTA). Material and methodsAll reports of cerebral CTA (1140) performed in one institution from March 2005 to December 2007 were analysed. We found 40 patients with single fenestrations of the intracranial arteries. All 40 examinations were retrospectively reviewed for location of vascular malformations and presence of aneurysms or subarachnoid haemorrhage (SAH). Medical histories of those patients were then analysed for evidence of SAH and referral reasons for CTA. ResultsForty fenestrated arteries were found in CTA: 18 basilar arteries (45%), 16 anterior cerebral arteries (40%), 4 anterior communicating arteries (10%) and one middle cerebral artery (2.5%). Only one vertebral artery fenestration was found due to the technique of the examination. Six patients (15%) with fenestrated arteries had a total of 8 aneurysms, although only one aneurysm was ipsilateral to the fenestration. In 8 cases of SAH, two were with no evidence of vascular malformation. The coexistence of CAF and aneurysms in CTA amounted to 15% (6/40), but the incidence of ipsilateral aneurysm was only 2.5% (1/40) and it affected the anterior cerebral artery. ConclusionsBasilar artery fenestration is the most frequent observed fenestration in CTA, followed by anterior cerebral artery and anterior communicating artery fenestrations. Coexistence of fenestration and aneurysm is uncommon in CTA examination.