Cerebral arterial fenestration

Duplication of the internal maxillary artery: Anatomical and clinical considerations

Duplication of the internal maxillary artery (IMAX) results from a failed regression of either the embryological superficial or deep ring and is reported to be exceedingly rare. We present a patient with this rare anatomical variant who was treated by endovascular technique in the clinical context of an acute oropharyngeal hemorrhage.

Intracranial arterial fenestrations associated with arteriovenous malformations diagnosed by CT angiography

BACKGROUND

Fenestrations involving aneurysms have been well documented. Only sporadic papers have been reported on fenestrations associated with AVMs (arteriovenous malformations) with few cases. Our study is to determine the rate of co-occurrence of fenestrations and AVMs and to analyze the possible relationship between them by CTA.

METHODS

Between January 2006 and February 2012, the CTA data of 5,657 consecutive patients were retrospectively reviewed.

RESULTS

A total of 12 cases (.21%) of fenestrations associated with AVMs were found. Of these, single-fenestrations were identified in 9 cases, and multifenestrations were found in 3 cases. Among 349 fenestrations, there were 15 cases of multifenestrations. The frequency of multifenestrations among fenestrated patients without AVMs was 3.6%. There was no significant difference in the incidence of AVMs in cases with and without fenestrations (3.4% and 2.7%), and there was no significant difference in the incidence of fenestration in cases with and without AVMs (7.7% and 6.1%, χ(2) = .643, P = .423).

CONCLUSIONS

CTA may play a vital role in assessing the anomalies of co-occurring AVM and fenestration, with an incidence of .21%. The frequency of multifenestrations in fenestrated cases with AVMs was higher than those without AVMs, though there is no significant association between fenestrations and AVMs.

Fenestrated vertebral artery

Fenestrations of the vertebral arteries (VAs) are usually identified angiographically. A left fenestrated vertebral artery (fVA) is reported here, identified in an adult specimen by microdissection. The distal segment of this VA was fenestrated and it consisted of two arms, the caudal one being larger than the cranial one. The caudal end of the rostral arm and the left posterior inferior cerebellar artery (PICA) were inserted at the same point. The anterior spinal artery was leaving the caudal arm of the fVA. On that side the anterior inferior cerebellar artery (AICA) was rudimentary, its cerebellar hemispheric territory being supplied by the PICA. The rostral arm of the fVA and the AICA were united by an anastomosis coursing on the ventral side of the olive. The AICA-to-fVA anastomosis, as well as the PICA, were supplying perforator arteries of the retro-olivary sulcus. Anatomical details of various arterial morphologies are important during specific surgical and interventional procedures.

Basilar artery hypoplasia

A rare case of segmental hypoplasia of the basilar artery is described in a 49-year-old man with transient vertebrobasilar ischemia, explored by magnetic resonance imaging (MRI) and digital angiography (DA). The embryology, clinical relevance and magnetic resonance findings of this arterial anomaly are discussed, with a review of six previously reported cases. Segmental aplasia was suggested in our case by magnetic resonance, and subsequently confirmed not only by time-of-flight magnetic resonance, but also by DA. Only ultrathin-slice T2-weighted images revealed the real finding of basilar artery hypoplasia. This sequence, not employed in previously reported cases, is mandatory to allow a clear differential diagnosis between basilar artery aplasia and hypoplasia.

Detection of cerebral artery fenestrations by computed tomography angiography

BACKGROUND AND PURPOSE

Cerebral 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 METHODS

All 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.

RESULTS

Forty 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.

CONCLUSIONS

Basilar 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.

Cerebral aneurysm in the long fenestration at the middle portion of m1 segment

We report a unique case of bilateral mirror image M1 aneurysms, one of which was an unruptured aneurysm arising from the proximal end of right middle cerebral artery fenestration with long loop and the other ruptured aneurysm from the contralateral side. We clipped ruptured aneurysm first and unruptured one in three months after the first operation. The difficulties of identifying this unusual vascular anomaly and possible problems during the surgery of an aneurysm at the site of fenestration are discussed with a review of the literature.

Concomitant dual origin and fenestration of the left vertebral artery resembling dissection

Dual origin and fenestration of the vertebral artery (VA) are very rare anomalies. Understanding of these variations, however, is important because they can be misdiagnosed as a VA dissection. A 42-year-old woman presented with motor weakness and sensory disturbance of the right upper extremity. Radiologic evaluations showed ectatic change in the right VA and an arteriovenous fistula between the right VA and the vertebral vein. We decided on endovascular occlusion of the proximal right VA and its fistulous portion. During the endovascular procedure, we had misunderstood the dual origin and fenestration of the VA as a dissection. Thus, failure to recognize these anomalies might result in unnecessary anticoagulation or therapeutic intervention. Clinicians should be alert to such VA variations when making a diagnosis and when planning any intervention or surgery involving the proximal VA.

Vertebrobasilar junction fenestration with dumbbell-shaped aneurysms formation: computational fluid dynamics analysis

BACKGROUND

We report 8 rare cases of paired ANs involving fenestrated vertebrobasilar junction and demonstrate the flow patterns of the paired ANs by qualitative CFD analysis in 5 cases.

METHODS

Two-dimensional and 3-dimensional angiographic features of 8 cases were reviewed. Nine patient-specific geometries of CFD models in 5 cases were created for flow analysis.

RESULTS

All 8 cases had 2 ANs, one large and the other small, projecting to the opposite sides at the proximal end of fenestrated vertebrobasilar junction. The different angiographic findings between right VA and left VA suggested the different hemodynamic characteristics of the respective VAs. Computational fluid dynamics analysis also demonstrated that the inflows of these paired ANs were different between right VA and left VA. Flow simulations by CFD were consistent with angiographic findings.

CONCLUSION

Intrinsic wall defects at fenestrated vertebrobasilar junction and specific hemodynamic stresses from 2 inflows may contribute to the formation of a pair of dumbbell-shaped ANs.

Endovascular treatment of basilar artery aneurysms associated with distal fenestration. A case report

SUMMARY

Segmental non-fusion of the basilar artery results from failed fusion of the neural arteries and from regression of the bridging arteries that connect the longitudinal arteries. This condition is associated with aneurysm formation in 7% of cases. Distally unfused arteries with associated aneurysms are very rare. We report on a case of successful endovascular treatment of an aneurysm of the distally unfused basilar trunk.

Three-dimensional visualization of vertebrobasilar system aneurysms in a vertigo patient

Cerebral artery fenestration refers to a division in the lumen of an artery leading to two distinct endothelium-lined channels. At the site of turbulent flow, fenestration may predispose to an aneurysm formation. In this study, a 45-year-old woman suffered an acute vertiginous attack after cervical manipulation. The MRI scan demonstrated basilar artery duplication and tortuous left distal vertebral artery impinging on the cisternal segment of the cochleovestibular nerve. Subsequent three-dimensional (3D) reconstruction by MR imaging showed vertebrobasilar artery fenestrations with aneurysms. Unfortunately, subarachnoid hemorrhage occurred 6 days later, and the patient became comatose one year after presentation. In summary, subarachnoid hemorrhage caused by vertebrobasilar system aneurysms is a life-threatening event. Delineating the configuration by 3D-reconstruction of MR images allows more accurate diagnosis and more effective management.

Segmental unfused basilar artery with kissing aneurysms: report of three cases and literature review

Basilar artery "fenestration" is the result of a failed fusion of the bilateral longitudinal neural arteries and can be associated with a saccular aneurysm, which typically arises at the proximal juncture of the unfused segment. "Kissing" aneurysms at this site, i.e. two aneurysms arising from the proximal junction of the unfused segment of the basilar artery pointing anteriorly and posteriorly are reported to be exceedingly rare. We present three patients with this rare condition, all of them being treated by endovascular techniques.

Neuroradiological Analysis of 23 Cases of Basilar Artery Fenestration Based on 2280 Cases of MR Angiographies

SUMMARY

Basilar artery (BA) fenestrations are the most frequently observed variant of the cerebral arteries. We examined the magnetic resonance (MR) angiographic incidence, location, characteristic configuration of BA fenestration and associated vascular disease. From April 2004 to September 2004, a total of 2280 cranial MR angiographies were performed at our institution. Twenty-three BA fenestrations (1.0%) were detected on MRA. There were 13 males and ten females in this group and mean age was 57.6 years old. Three cases of these fenestration group are suffered with atherothrombic infarction in the territory of vertebro-basilar system. Seven of 23 cases (30%) were associated with intracranial aneurysm. Of those four cases, aneurysms were located at anterior circulation. Of those three cases, the aneurysms were associated with BA fenestration. Since saccular aneurysms are reported to arise frequently at BA fenestration, knowledge and recognition of fenestration are useful and important in the interpretation of cerebral MR angiography.

Ruptured saccular aneurysm of distal vertebral artery fenestration managed with Guglielmi detachable coils and intraventricular tissue plasminogen activator

BACKGROUND

Aneurysms associated with vertebrobasilar fenestrations are uncommon. We report on an unusual presentation of such aneurysm with a dedicated arterial pedicle, manifesting with significant intraventricular hemorrhage. Equally important, the aneurysm was managed in a multidisciplinary fashion, which, we think, greatly contributed to a good outcome.

CASE DESCRIPTION

A 55-year-old man presented in good condition after subarachnoid and massive intraventricular hemorrhage. The aneurysm location and the extent of intraventricular hemorrhage both presented concerns regarding treatment approach. The aneurysm was first treated with transarterial coil obliteration, and intraventricular tissue plasminogen activator (tPA) infusion was given, with rapid resolution of evolving hydrocephalus. The patient had an excellent outcome.

CONCLUSION

To our knowledge, this is the first report of a vertebrobasilar fenestration saccular aneurysm with a dedicated pedicle projecting toward the foramen of Magendie with significant intraventricular hemorrhage. In addition, this patient was successfully managed with endovascular obliteration and intraventricular tPA infusion.

Vertebrobasilar junction aneurysms associated with fenestration: experience of five cases treated with Guglielmi detachable coils

BACKGROUND

Fenestration of vertebrobasilar junction is a rare congenital anomaly and often associated with aneurysm formation. We describe five cases of vertebrobasilar junction aneurysms in four patients associated with fenestration, which were treated with endovascular coil occlusion using Guglielmi detachable coils (GDCs). The importance of preoperative computed tomography (CT) angiography to understand the complex anatomy of fenestration and aneurysm is emphasized.

CASE REPORTS

Three patients presented with subarachnoid hemorrhage and one patient presented with headache only. Among 3 patients with subarachnoid hemorrhage, 1 patient was referred for endovascular coil occlusion after clipping of ruptured distal ACA aneurysm. A six-French guiding catheter was placed in the left vertebral artery via right femoral artery, except for 1 patient who had two vertebrobasilar junction aneurysms with complex anatomic relationship, accessed bilaterally. Five vertebrobasilar junction aneurysms with fenestration were treated with endovascular coil occlusion using GDCs. Postoperative angiography demonstrated successful occlusion of aneurysmal sac with preservation of basilar artery.

CONCLUSIONS

Vertebrobasilar junction aneurysms are frequently associated with fenestrations. In addition to vertebral angiography on both sides, CT angiography may be a valuable tool for better understanding of complex anatomy of aneurysms associated with fenestration. The surgically difficult aneurysms such as vertebrobasilar junction aneurysm with fenestration can be successfully treated with GDCs.

Aneurysm originating from the fenestration of the posterior cerebral artery: case report

OBJECTIVE AND IMPORTANCE

A rare case of an aneurysm arising at the fenestration of the P2 segment of the posterior cerebral artery is reported.

CLINICAL PRESENTATION

A 37-year-old man presented with severe headache and disturbance of consciousness. Computed tomographic scanning showed diffuse subarachnoid hemorrhage. Cerebral angiography revealed an aneurysm at the fenestration of the P2 segment of the right posterior cerebral artery. The aneurysm was located at the middle portion of the lower trunk of the fenestration. An unruptured arteriovenous malformation was incidentally found in the right thalamus.

INTERVENTION

A right frontotemporal craniotomy with orbitozygomatic osteotomy was made, and the aneurysm was successfully clipped. One year after the operation, gamma knife surgery was performed for the right thalamic arteriovenous malformation.

CONCLUSION

This is the first reported case of an aneurysm originating from the middle portion of a fenestrated posterior cerebral artery.

Ruptured vertebrobasilar junction aneurysm associated with basilar artery fenestration

A case of a ruptured saccular aneurysm arising from the proximal portion of a partially duplicated basilar artery in a 36-year-old woman is reported. CT and lumbar puncture confirmed subarachnoid haemorrhage. Cerebral angiography detected a vertebrobasilar junction aneurysm associated with basilar artery fenestration. The patient underwent successful clipping and coating of the aneurysm by a right lateral suboccipital osteoclastic approach. Embryological development, pathogenesis, diagnostic and therapeutic difficulties of this vascular malformation are discussed in this report.

A ruptured aneurysm at the distal end of the basilar artery fenestration associated with multiple fenestrations of the vertebrobasilar system: case report

BACKGROUND

An aneurysm at the fenestrated basilar artery usually arises at the proximal end of the fenestration, with few exceptions. We failed to reveal any case of aneurysm at this site associated with multiple fenestrations of the vertebrobasilar system.

CASE REPORT

This 62-year-old male was admitted to our hospital 1 day after a sudden onset of headache. CT scan showed subarachnoid hemorrhage, and angiogram revealed an aneurysm at the distal end of the fenestrated basilar artery in association with two other fenestrations of the vertebrobasilar system. The limb of the basilar artery fenestration was trapped tightly with one clip through the transcondylar approach. Postoperative course was uneventful, and postoperative angiogram showed complete disappearance of the aneurysm.

CONCLUSION

An extremely rare case of an aneurysm at the distal end of the fenestrated basilar artery in association with multiple fenestrations of the vertebrobasilar system is reported. The coexistence of vertebral artery fenestration and the fenestration of the vertebrobasilar junction may give a clue to the mechanism of occurrence of basilar artery fenestration.

The layered fabric of cerebral artery fenestrations

BACKGROUND AND PURPOSE

Intravascular bridges, resulting from developmental anomalies of brain arteries, are now better known as arterial fenestrations. Their tendency to develop aneurysms, similar to arterial bifurcations, makes their anatomy and microstructure important for study.

METHODS

Six segments of artery, each including a fenestration (five from the vertebrobasilar junction and one from the middle cerebral artery), were pressure distended, fixed, and sectioned. We made three-dimensional orientation measurements of smooth muscle and collagen, stained to enhance their birefringence, using the polarized light microscope.

RESULTS

The general contour of the fenestrations is streamlined with a thickened layered subendothelium at the trailing or distal edge, structurally similar to the region of convergence of major brain arteries. Defects of the medial layer were found at both proximal and distal edges of all the fenestrations. Results included regional mean orientations of individual layers, with circular SDs. The medial layer was found to be coherently aligned perpendicular to the direction of blood flow, with a mean circular SD of 12 degrees. The adventitia was less coherent (mean circular SD, 16 degrees) with the same average orientation, and the multilayered subendothelium had layers of obliquely oriented fibers with a wide range of coherence for individual fiber groups. Layers of the side regions were analogous to those in segments of brain artery and differed significantly from the proximal and distal edges of the fenestration structure.

CONCLUSIONS

The plasticity of form of the fenestrations at both the proximal and distal edges is in response to hemodynamic forces and is analogous to branching regions of brain arteries. Medial defects, a common feature in both brain arteries and fenestrations, may predispose the arterial fenestration to aneurysm formation.

Ectasia and fenestration of the anterior cerebral artery associated with persistent trigeminal artery: case report

Multiple vascular anomalies in a 22-year-old patient who had signs and symptoms of vestibulocochlear dysfunction are reported. Angiography revealed a fenestration of the proximal segment of the left anterior cerebral artery, an ectasia of the left anterior and posterior cerebral arteries, and a persistence of the right trigeminal artery. The rarity of the association is documented, and the clinical significance is discussed.

Fenestration of the supraclinoid internal carotid artery associated with carotid bifurcation aneurysm

Fenestration of the internal carotid artery is extremely rare. The authors describe a fenestration at the supraclinoid portion of the left internal carotid artery revealed after subarachnoid hemorrhage from an ipsilateral carotid bifurcation aneurysm. This is the third reported case of fenestration of the intracranial internal carotid artery. Fenestrated cerebral vessels and their possible genesis and surgical management are discussed.

A partially thrombosed, fenestrated basilar artery mimicking an aneurysm of the vertebrobasilar junction: case report

We report a patient with a subarachnoid hemorrhage in whom a partially thrombosed, fenestrated basilar artery mimicked an aneurysm of the vertebrobasilar junction on preoperative angiography. Intraoperatively, no aneurysm was detected; instead, the patient was found to have partial thrombosis of one limb of the fenestrated basilar artery. The nodular appearance of the residual lumen of the vessel corresponded exactly to the angiographic findings. To our knowledge, no similar case has been reported.

Cerebral arterial fenestrations associated with intracranial saccular aneurysms

Fenestrations of cerebral arteries other than the anterior communicating artery are rare congenital anomalies, which may be associated with saccular aneurysms. In such cases, the aneurysms may be located at the fenestration itself or may involve other intracranial vessels. This kind of association is not infrequently the cause of angiographic diagnostic problems, as well as surgical difficulties, and consequently needs to be well known to physicians. Four recent cases of rare fenestrations of cerebral arteries associated with intracranial aneurysms are reported in this study and discussed together with a review of the literature.

Multiple arterial fenestrations, multiple aneurysms, and an arteriovenous malformation in a patient with subarachnoid hemorrhage

We report the case of a 49-year-old, right-handed man with multiple vascular pathologies, including a fenestrated anterior communicating artery and middle cerebral artery, an aneurysm of the anterior communicating artery, multiple aneurysms of the middle cerebral artery, and an arteriovenous malformation. Diagnoses were made through computed tomography, cerebral angiography, magnetic resonance imaging, and intraoperative dissection. The lesions were managed surgically in stages with satisfactory results. Congenital and hemodynamic factors may have combined to manifest in the anomalies present in this unique case. We believe that no similar combination of vascular pathology has been reported previously.