Basilar artery dolichoectasia. Review of the literature and six patients studied with magnetic resonance angiography

Role of a Tortuous Vertebrobasilar Artery and Anchoring Perforators in the Etiology of Hemifacial Spasm

BACKGROUND

In >70% of patients with hemifacial spasm (HFS), the offending artery is either the anterior inferior cerebellar artery (AICA) or posterior inferior cerebellar artery (PICA), without a tortuous vertebrobasilar artery (VBA). We hypothesized that anchoring perforators around the root exit zone (REZ) of the AICA or PICA might induce vascular deviation and compression. We investigated the occurrence of these perforators from the AICA or PICA and the extent of VBA tortuosity to reveal the pathology of vascular compression.

METHODS

This retrospective review included 110 patients after excluding those with vertebral artery (VA) compression alone. The occurrence of perforators was determined according to operative findings within 5 mm of the REZ, and VBA tortuosity was evaluated using MATLAB. We analyzed the association between perforators, VBA tortuosity, and the surgical implications.

RESULTS

The occurrence of perforators from the offending AICA or PICA around the REZ was significantly higher in the group without VA compression (Group A) than in the group with VA compression (Group B). VBA tortuosity was significantly lower in Group A. VBA tortuosity was inversely correlated with the presence of AICA or PICA perforators in all 110 patients. Operative results were similar between the groups, although patients with low VBA tortuosity tended to require interposition in decompression procedures.

CONCLUSIONS

Anchoring perforators around the REZ play a crucial role in vascular compression for patients with less tortuous VBAs. Moreover, surgeons should be prepared to deal with multiple perforators in a more complicated surgery in cases of less tortuous VBA.

Congenital and acquired anomalies of the basilar artery: A pictorial essay

INTRODUCTION

The basilar artery is one of the two cases in our body where an arterial vessel is formed by the union of two others - the vertebral arteries. It provides vascular supply to essential structures for the main vital functions; the posterior cerebral arteries originate from it as terminal branches, and form part of the anastomotic circle of Willis.

IMAGING FINDINGS

Congenital and acquired anomalies of the basilar trunk are described. We provide a schematic and detailed representation of normal anatomical variants - mainly represented by the fenestrated basilar artery or the persistence of carotid-basilar anastomosis; course anomalies are also illustrated, with reference to neuro-vascular conflicts and dolichoectasia. Among congenital anomalies, this pictorial review also shows the variants of the basilar origin, such as in the case of basilar trunk arising from only one of the two vertebral arteries, and the calibre changes - which are represented by aneurysm and hypoplasia. The latter appears to be a risk factor for posterior circulation stroke, when associated with a bilateral posterior foetal variant.Among the acquired forms, this pictorial essay describes some clinical cases of dissections, non-congenital aneurysms, thrombosis and tumour with vascular encasing or compression of basilar artery.

CONCLUSION

CT angiography and MRI allow us to study the posterior intracranial circulation in detail, providing useful pre-treatment information. Therefore, knowledge of congenital or acquired anomalies of the basilar artery is essential for radiologists, neuroradiologists and neurosurgeons.

Usefulness of vertebrobasilar artery radiological finding as a predictive and prognostic factor for sudden sensorineural hearing loss

OBJECTIVE

The association between sudden sensorineural hearing loss (SSNHL) and radiological findings of the vertebrobasilar artery is not well-known and little research has been done. We hypothesized that the radiological features of the vertebrobasilar artery contribute to the incidence and prognosis of SSNHL.

METHODS

We retrospectively enrolled patients diagnosed with unilateral SSNHL (SSNHL group) and those with acute vestibular neuritis (AVN; control group) in our hospital. All patients underwent magnetic resonance imaging and computed tomography. We measured the following parameters on the radiological images: basilar artery diameter, direction and distance of basilar artery deviation, direction and distance of vertebral artery deviation, and incidence of vertebral artery obstruction. Pure tone audiometry (PTA) was performed in all patients. Follow up PTA between 1 week and 1 month after treatment was performed in the SSNHL group.

RESULTS

A total of 244 SSNHL patients and 62 AVN patients were included in the analysis. Age, body mass index, and basilar artery diameter were found to be significantly associated with SSNHL. In the SSNHL group, patients were divided into three subgroups based on the consistency between the basilar artery deviation site and disease site. No significant difference was noted in initial PTA, final PTA, PTA recovery, and symptom improvement among the three groups. In case of the basilar artery, when the deviation and disease sites were in the opposite direction and the basilar artery diameter was >3.5 mm, diameter of basilar artery was positively correlated with PTA recovery.

CONCLUSIONS

The strength of this study is that radiological evaluation of the vertebrobasilar artery was performed. Further research on the association between SSNHL and radiological features of the vertebrobasilar artery should be conducted to emphasize the importance of vascular assessment in SSNHL.

Severe vertebrobasilar dolichoectasia as a cause of obstructive hydrocephalus: A case report

RATIONALE

Dolichoectasia of the vertebrobasilar artery is a vascular anomaly characterized by marked elongating, widening, and tortuosity of the arteries. Although this anomaly is usually asymptomatic, it may present with ischemic symptoms or mass effect involving brainstem or cranial nerves.

PATIENT CONCERNS

A 52-year-old male was admitted with headache and visual field defect.

DIAGNOSES

Computed tomography and magnetic resonance imaging showed noncommunicating hydrocephalus due to vertebrobasilar dolichoectasia.

INTERVENTIONS

The patient underwent right-side ventriculoperitoneal shunt.

OUTCOMES

The patient's symptoms improved gradually, although visual symptoms persisted.

LESSONS

Neurosurgeons need to keep in mind vertebrobasilar dolichoectasia as a rare cause of obstructive hydrocephalus for accurate diagnosis and swift treatment.

Fatal subarachnoid hemorrhage following ischemia in vertebrobasilar dolichoectasia

Vertebrobasilar dolichoectasia (VBD) is a chronic disorder with various cerebrovascular and compressive manifestations, involving subarachnoid hemorrhage (SAH). Occurrence of SAH shortly after worsening of clinical VBD symptoms has occasionally been reported. The goal of the study was to examine this association, in particular its pathophysiology, clinical precursor signs, time course, and outcome.To this end, in a retrospective multicenter study, we analyzed 20 patients with VBD and SAH in regard to preceding clinical symptoms, presence of vertebrobasilar thrombosis and ischemia, outcome and neuropathological correlates.Median age of the 7 female and 13 male patients was 70 years (interquartile range [IQR] 18.3 years). Fourteen patients (70%) presented with new or acutely worsening posterior fossa signs at a median of 3 days prior to SAH (IQR 2, range 0.5-14). A thrombus within the VBD was detected in 12 patients (60%). Thrombus formation was associated with clinical deterioration (χ = 4.38, P = 0.04) and ponto-cerebellar ischemia (χ = 8.09, P = 0.005). During follow-up after SAH, 13 patients (65%) died, after a median survival time of 24 hours (IQR 66.2, range 2-264 hours), with a significant association between proven ponto-cerebellar ischemia and case fatality (χ = 6.24, P = 0.01).The data establish an association between clinical deterioration in patients with VBD, vertebrobasilar ischemia, and subsequent SAH. Antithrombotic treatment after deterioration appears controversial and SAH outcome is frequently fatal. Our data also indicate a short window of 3 days that may allow for evaluating interventional treatment, preferably within randomized trials.

Multimodality Imaging of Vertebrobasilar Dolichoectasia: Clinical Presentations and Imaging Spectrum

Vertebrobasilar dolichoectasia (VBD) is characterized by ectasia, elongation, and tortuosity of the vertebrobasilar arteries, with a high degree of variability in clinical presentation. The disease origin is believed to involve degeneration of the internal elastic lamina, thinning of the media secondary to reticular fiber deficiency, and smooth muscle atrophy. The prevalence of VBD is variable, ranging from 0.05% to 18%. Most patients with VBD are asymptomatic and their VBD is detected incidentally; however, it is important to recognize that the presence of symptoms, which can lead to clinically significant morbidity and sometimes mortality, may influence clinical management. The most important clinical presentations of VBD are vascular events, such as ischemic stroke and catastrophic intracranial hemorrhage, or progressive compressive symptoms related to compression of adjacent structures, including the cranial nerves, brainstem, or third ventricle, causing hydrocephalus. The imaging diagnostic criteria for computed tomography and magnetic resonance (MR) imaging include three quantitative measures of basilar artery morphology: laterality score, height of bifurcation, and basilar artery diameter. The authors review the relevant anatomy and disease origin of VBD; pertinent imaging findings, including intraluminal thrombus and relation to the cranial nerves; and imaging pitfalls, such as the hyperintense vessel sign on MR images and artifacts related to slow flow in the dolichoectatic vessel. In addition, clinical manifestations, the role of radiology in diagnosis and management of this condition, and available management options are reviewed. (©)RSNA, 2016.

Dolichoectasia of the circle of Willis arteries and fusiform aneurysm of basilar artery - case report and review of the literature

Background:

Dolichoectasia of intracranial arteries is a rare arteriopathy characterized by elongation and widening of the arteries and disturbance of the laminar blood flow. It involves mostly vertebral and basilar arteries. In advanced cases, formation of a fusiform aneurysm is possible.

Case Report:

A sixty-four-year-old female with hypertension was admitted to the hospital with severe non-systemic vertigo and dysarthria, which had lasted for a couple of weeks. Imaging of the brain revealed dolichoectasia of arteries of the circle of Willis coexisting with a fusiform aneurysm of the basilar artery.

Conclusions:

Intracranial arterial dolichoectasia may be asymptomatic for a long time. However, in many cases it leads to neurological symptoms associated with haemodynamic disturbance (due to unstable wall clots) and mass effect caused by the widened vessel.

Vertebrobasilar dilatative arteriopathy (dolichoectasia)

Dolichoectasia (dilatative arteriopathy) describes marked elongation, widening, and tortuosity of arteries. The intracranial vertebral and basilar arteries are preferentially involved. Dolichoectatic arteries usually have an abnormally large external diameter and a thin arterial wall, with degeneration of the internal elastic lamina, multiple gaps in the internal elastica, thinning of the media secondary to reticular fiber deficiency, and smooth muscle atrophy. The most important clinical presentations of dilatative arteriopathy include acute brain ischemia; a progressive course related to compression of cranial nerves, the brain stem, or the third ventricle; and catastrophic outcome caused by vascular rupture. Flow in dilated arteries can become bidirectional, resulting in reduced antegrade flow and thrombus formation. Elongation and angulation of arteries can stretch and distort the orifices of arterial branches, leading to decreased blood flow, especially in penetrating branches.

Pulsatile tinnitus in cerebrovascular arterial diseases

In a prospective study of 100 patients evaluated at the University of Wisconsin Stroke Program, we sought to document cases of incidental pulsatile tinnitus that could be ascribed to stenotic, occluded, ectatic, tortuous, or dissected craniocerebral arteries. Angiographic detail, magnetic resonance angiography, catheter-generated x-ray angiography, or both were necessary for inclusion into either Group 1 (n=29), those with pulsatile tinnitus, or Group 2 (n=71), those without pulsatile tinnitus. Patients did not appear to have head/neck tumors, aneurysms, arteriovenous malformations, transmitted cardiac murmurs, or venous etiologies for their tinnitus. Age, sex, and stroke risk factor profiles did not separate the two groups. Factors that were significantly more common in Group 1 included (1) severe, > or =70% stenosis through complete occlusion, internal carotid artery disease (59% for Group 1 v 21% for Group 2, P<.05); (2) severe, > or =50% stenosis through occlusion, vertebral or basilar disease (38% v 18%, P<.05); (3) tortuosity of at least one carotid, vertebral, or basilar artery (31% v 18%, P<.05); and (4) basilar artery dolichoectasia (14% v 0%, P=.006). We also noted when pulsatile tinnitus was either "objective" (11 of 100, 11%) or "subjective" (18 of 100, 18%), duration of tinnitus, transient versus permanent nature of tinnitus, and reasons seen in consultation by one of us.

Basilar artery dolichoectasia in a boy with a combination of partial monosomy 18p and partial trisomy 20q

We describe an 11-year-old boy with facial dysmorphism consisting of a round and flat face, hypertelorism, short nose, and down turned corners of the mouth. In addition, he had severe mental retardation, short stature, imperforate anus, and basilar artery dolichoectasia. Cytogenetic evaluation revealed an unbalanced paternally inherited translocation t(18;20)(p11.2q13.3), resulting in partial monosomy 18p and partial trisomy 20q. The combination of deletion 18pduplication 20q has not been previously described and we suggest that the unusual finding of basilar artery dolichoectasia may be a feature of one of the imbalances.

The mechanism of ischemic stroke in patients with dolichoectatic basilar artery

Basilar artery dolichoectesia (BD) may cause brainstem ischemia by multiple mechanisms, including thrombosis, embolism, occlusion of deep penetrating arteries. The objective of this study was to determine and characterize clinical, imaging findings and hemodynamic mechanisms in patients with cerebrovascular event associated with BD and compare these data with those for patients with BD who did not have stroke. We studied 29 consecutive stroke, two transient ischemic attack (TIA) patients with BD who have been admitted to our stroke unit. We sought the diameter of ectasia, height of the bifurcation, lateral displacement, shape deformities, and blood flow velocity of the basilar artery (BA) by transcranial Doppler. Imaging and hemodynamic findings were compared with those found in a group of 18 patients without stroke or TIA. The main infarct localization was pons, eight (28%) with restricted single lesion, 10 (32%) with multiple lesions involving thalamus, midbrain, posterior cerebral artery (PCA) territory. Patients with BD were more probably to have had stroke fitting a clinical and imaging patterns of multiple infarcts than those with restricted infarct in territories supplied by branches of the BA (60% vs. 40%). Hypertension and atherosclerotic changes of the posterior circulation were more frequent in patients with stroke than those without (P = 0.004 and P = 0.028, respectively), whilst the incidence of other vascular risk factors were not significantly different in two groups. Patients with stroke/TIA had more often low blood flow velocity but not significant in the BA when compared with those for BD patients without cerebrovascular event (71% vs. 39%; P = 0.1). Reduced blood flow velocity in the BA was correlated significantly with distal lesions involving thalamus, midbrain and PCA territory rather than those located in the territory supplied by branches of the BA (P = 0.02). In conclusion, it seems probably that BD may cause vertebrobasilar system ischemia by multiple mechanisms, especially reduced blood flow in the BA and atheromatous changes in the vertebrobasilar system may precipitate thromboembolic stroke.

Cochlear vertebral entrapment syndrome: a case report

The authors describe a patient with isolated involvement of vestibulocochlear nerve by a huge vascular loop from vertebral dolichoectasia. No other neurological deficit was found except for unilateral hearing loss. Abnormal brainstem auditory evoked potential study indicated a retrocochlear lesion. The brain computed tomography (CT) and magnetic resonance imaging (MRI) studies demonstrated an abnormally enhanced vascular lesion impinged on the left porus acusticus with a displacement of the brainstem to the right. There was no infarction in the brainstem. A cerebral angiography demonstrated a megadolichoectatic horizontal loop at the intracranial portion of the left vertebral artery. There was no thrombus or atherosclerosis in the vertebrobasilar system. A mechanical compression by a vascular loop is the only possible pathogenesis for hearing loss. The authors diagnose this condition as cochlear vertebral entrapment syndrome.

Catastrophic subarachnoid hemorrhage resulting from ruptured vertebrobasilar dolichoectasia: case report

OBJECTIVE AND IMPORTANCE

Two patients with vertebrobasilar dolichoectasia sustained massive fatal subarachnoid hemorrhage from rupture of the basilar artery wall. Hemorrhage from this entity is not widely known to occur during its natural history and may be exacerbated by systemic anticoagulation.

CLINICAL PRESENTATION

Two patients presented with ischemic events of the brain stem, which were attributed to vertebrobasilar dolichoectasia. The diagnosis was made on the basis of computed tomography and subsequent angiography.

INTERVENTION

Both patients were treated with systemic anticoagulation with heparin and subsequently experienced massive fatal subarachnoid hemorrhage. Autopsy results confirmed the cause of hemorrhage to be frank rupture of the basilar artery wall.

CONCLUSION

Vertebrobasilar dolichoectasia is a formidable structural entity afflicting the posterior circulation, which is generally thought to cause symptoms as a result of either compression of the adjacent brain stem and/or cranial nerves or ischemic events caused by thrombosis and perforator occlusion. Our experience with these two patients indicates that some lesions can hemorrhage, which is a factor that must be weighed when considering treatment alternatives.