Basilar Artery Hypoplasia Research Articles

Basilar artery hypoplasia with persistent fetal circulations misinterpreted as basilar artery occlusion in a non-invasive angiography

Basilar artery hypoplasia with persistent fetal circulations misinterpreted as basilar artery occlusion in a non-invasive angiography

Persistent trigeminal artery in a patient with posterior circulation stroke treated with rt-PA: case report

BackgroundA persistent trigeminal artery (PTA) is a non-involuted embryonic vessel that connects the cavernous part of the internal carotid artery with the posterior circulation. In the adult it is associated with multiple pathological conditions including trigeminal neuralgia, ophthalmoplegia, hypopituitarism, intracavernous fistula, brain aneurysms and posterior circulation strokes. The latter may occur through steal phenomena or thrombosis in the anterior circulation. PTA associated vertebrobasilar hypoplasia has yet to be associated to TIA like events, however, in the reported case, that seems to be the case with reported vertigo being probably linked to vertebrobasilar insufficiency.Case reportWe present a case of an 82-year-old man with sudden onset neurological deficits, including left hemiparesis with crural predominance, vertical nystagmus, right internuclear ophthalmoplegia, dysarthria and dysmetria on the left arm. CT angiography disclosed basilar artery hypoplasia in the proximal two thirds and a persistent trigeminal artery. He was diagnosed with acute ischemic stroke. He was submitted to rt-PA with partial reversion of deficits.ConclusionThe ischemic events related to PTA remain a rare cause of stroke with specific pathophysiological mechanisms and implications. They may occur through steal phenomena or thrombosis in the anterior circulation. Upon literature review, in the described case both mechanisms seem possible, however the transient episodes of vertigo could have been the first sign of vertebrobasilar insufficiency.

Prevalence and Clinical Implications of the Primitive Trigeminal Artery and its Variants: A Meta-Analysis

The primitive trigeminal artery (PTA) is the most common and the largest persistent carotid-basilar anastomosis. Primitive trigeminal artery variants (PTAVs) are anastomoses between the internal carotid artery and cerebellar arteries. These vessels pose a risk of hemorrhagic or ischemic complications during neurosurgical procedures in the parasellar and intrasellar regions. The aim of this study was to determine the prevalence of both PTA and PTAVs and their clinically important anatomic features. Major electronic databases were thoroughly searched for studies on PTA and PTAV. References in the included articles were also evaluated. Data regarding prevalence, laterality, origin, course patterns, and associated anomalies were extracted and pooled into a meta-analysis. A total of 39 studies (110,866 patients) were included in the meta-analysis. The total pooled prevalence estimate of PTA and PTAVs combined was 0.4% (95% confidence interval [CI], 0.3-0.5). Individually, PTA was present in 0.3% of patients and PTAV in 0.2%. Both arteries most often originated from the C4 internal carotid artery and took a course lateral to the dorsum sellae. The anterior inferior cerebellar artery type was the predominant PTAV (72.1%). Basilar artery hypoplasia was found in 42.5% of patients with a PTA. PTA and PTAVs are rare vessels, but they are clinically important because they can contribute to trigeminal neuralgia. Knowledge of the potential course of these arteries is essential in neuroradiology and neurosurgery, especially in minimally invasive procedures such as the endoscopic endonasal transsphenoidal approach to the pituitary gland and the percutaneous gasserian ganglion procedure.

Basilar Artery Hypoplasia with Embryonic Origin of Anterior Cerebral Arteries: A Radiological Gamut

Aims and Objectives: This article aims to determine the most frequent cause of basilar hypoplasia and evaluate the potential impact of associated pathological findings simultaneously. Material and Methods: We have retrospectively reviewed the patients in our archive with basilar hypoplasia and embryonic origin of ACPs. These patients have been studied using 3D TOF with 3D-VR reconstruction. The studies have been carried out using MRI of 1.5 and 3T. Several of them have also undergone cerebral angiography by digital subtraction. Results: The most frequent cause of basilar hypoplasia has been associated with the embryonic origin of both bilateral ACPs with 27 cases. In 3 cases, the basilar artery hypoplasia has been associated with persistent trigeminal artery. In 25 patients studied the basilar hypoplasia was an incidental finding in the context of a routine MRI study including angio MRI sequences. Of the patients studied only 5 had allegedly clinical history that could be related to hypoplastic basilar artery. Conclusion: Hypoplasia of basilar artery is a related variant, in most cases, with both embryonic origins of ACPs. In most of the patients studied, this was an incidental finding. However the said variant may be a predisposing factor to cause any grade of vascular insufficiency in the territory of vertebro-basilar artery. With respect to the aneurysm, associated described persistent trigeminal artery is thought likely may have a causal relationship with this variant.

Basilar artery hypoplasia associated with changes of brainstem potential, transcranial Doppler and perfusion-weighted imaging

Objective: The aim of this study was to observe brainstem hemodynamic alterations associated with basilar artery hypoplasia (BAH). Methods: Nine hundred and fifty-two consecutive patients received emergency multimodal computed tomography; magnetic resonance imaging and magnetic resonance angiogram during the period of January 2011 to December 2014 were included. The vascular risk factors, brainstem auditory evoked potential (BAEP), blink reflex (BR), transcranial Doppler (TCD) and dynamic susceptibility contrast-enhanced perfusion-weighted imaging were completed. Results: There was significant difference in the abnormal rates of TCD and BAEP between BAH and non-BAH patients. A positive correlation between basilar artery diameter and systolic velocity among BAH patients was suggested. V-wave value was used to predict posterior circulation infarction (PCI) with the sensitivity of 0.933 and specificity of 0.50 with the cutoff value of 5.97 s. Abnormal BR rate was also significantly different in BAH and non-BAH patients. The latency of R2 was used to predict PCI with the sensitivity of 0.933 and specificity of 0.50 with the cutoff value of 46.4 ms. The incidence of hypoperfusion was higher in BAH than non-BAH group and it was significant difference. Conclusion: BAH is closely associated with hemodynamic alterations within the pons, which might contribute to vascular vertigo due to regional hypoperfusion.

Cerebrovascular and Brain Abnormalities in Autosomal- Dominant Polycystic Kidney Disease: Role of 3d Time-of-Flight Magnetic Resonance Angiography

Introduction: The association of intracranial aneurysms and autosomal-dominant polycystic kidney disease (ADPKD) is well recognized. The aim of this study was to assess the prevalence of asymptomatic intracranial aneurysms and to verify the presence of other cerebral abnormalities in patients with ADPKD by Magnetic Resonance Angiography screening. Materials and methods: From January 2009 to September 2013, 56 patients with ADPKD (25 M, 31 F; mean age 40 years, range 24- 63 years) underwent brain Magnetic Resonance Imaging including 3D time-of-flight MR angiography and T2-weighted Turbo-Spin-Echo axial sequences. Magnetic Resonance studies were examined by two experienced neuroradiologists (20 years). If an intracranial aneurysm was detected, cerebral Computed Tomography Angiography was recommended and further action were discussed with the interventional neuroradiologist. Results: Nine saccular intracranial aneurysms were detected in 56 patients, located in the anterior circulation (5 internal carotid arteries, 1 anterior communicating artery and 3 middle cerebral arteries). Four patients underwent endovascular treatment with flow-diverter devices. We additionally found internal carotid artery abnormal diameter and course (6), basilar artery hypoplasia (1), basilar artery dolichoectasia (1), asymmetric anterior cerebral (4) and vertebral (14) arteries, vascular anatomic variants (3), venous drainage anomaly (1), arachnoid cysts (6), large bilateral choroid plexus cysts (1) and mega cisterna magna (2). Conclusions: The prevalence of asymptomatic intracranial aneurysms (16.1%), higher compared to the general population (1%) and similar to literature reports in autosomal dominant polycystic kidney disease (6-16%), confirmed the importance of the Magnetic Resonance Angiography screening in these patients.

Association between basilar artery hypoplasia and posterior circulation infarction

To explore the relationship between basal artery hypoplasia (BAH) and posterior circulation ischemic stroke and its clinical characteristics to improve the understanding of BAH. A total of 328 hospitalized patients from April 2012 to April 2014 were enrolled retrospectively. With normal course and regular shape of basilar artery on brain magnetic resonance angiography (MRA), other causes of posterior circulation ischemic stroke were excluded. They were divided into BAH (n = 48) and non-BAH (n = 280) groups according to the morphology and diameter of basilar artery on head MRA. We compared the general information and intracranial vascular variations between two groups, especially the incidence rate of posterior circulation infarction and mean blood flow velocity (Vm) of basal artery by analyzing clinical information and MRI findings. Meantime, their clinical outcomes were observed through follow-ups. And detailed clinical features were discussed for the patients with posterior circulation infarction in the BAH group. (1) The concurrent lesions included vertebral artery intracranial segment hypoplasia (n = 24, VAH), fetal type posterior artery (n = 18, FTPA), persistent trigeminal artery (n = 1) and giant fenestration variation on vertebral artery (n = 1) in the BAH group. In comparison, it was more liable to cranial vascular variations in the BAH group (P < 0.05). (2) The incidence rates of posterior circulation infarction for two groups were 35.4% (17/48) and 8.6% (24/280) respectively. In comparison, these cases in the BAH group were more likely to suffer from posterior circulation ischemic stroke (P < 0.05) and the Vm of basal artery in the BAH group was obviously lower than that in the non-BAH group (P < 0.05). (3) these cases with stroke in two groups had no mortality during a follow-up period of 4-28 months. There were 3 cases with recurrent posterior circulation stroke in the non-BAH group. The number of cases with mRS scoring 2 points or less in the BAH group was more than that in the non-BAH group at discharge, 30 or 90 days after discharge (P < 0.05). (4) these cases with posterior circulation stroke in the BAH group often presented as lacunar syndrome (9/17), paramedian infarction in pons (9/17) and bilateral VAH plus unilateral FTPA (8/17). As a relatively rare disease, BAH often has other intracranial vascular variants. Posterior circulation stroke occurs due to reduced blood supply of vertebrobasilar system, especially pons infarction. Though with relatively good clinical outcomes, we still need to make an early diagnosis and strengthen stroke prevention.

Imaging characteristics of basilar artery hypoplasia

To determine the imaging characteristics of basilar artery hypoplasia (BAH). From October 2009 to August 2013, 10 193 magnetic resonance angiogram (MRA) and 31 716 magnetic resonance imaging (MRI) consecutive cases were retrospectively retrieved from our institutional Picture Archiving and Communication System (PACS) database. BAH was defined as a continuous diameter reduction all over artery and a basilar artery diameter ≤ 2 mm. The same cut-off value was applied for vertebral artery hypoplasia (VAH). We measured the diameters of basilar and vertebral arteries with PACS in all patients according to source imaging and IMP construction of MRA. The carotid arterial computed tomography angiogram (CTA) profiles were reviewed in 50 patients. The fetal-type posterior circle of Willis (FTP) was assessed. The diagnosis of acute cerebral infarction was based on clinical symptoms, signs and a high signal on diffusion-weighted imaging (DWI). Acute cerebral infarction was divided into anterior circulation stroke (ACS) and posterior circulation stroke (PCS). A total of 210 BAH were identified among 10 193 consecutive patients. BAH was more common in females (56.7%) than males (43.3%) in the patient group. They had a fetal-type of posterior cerebral artery (FTP) (175 bilateral (83.3%), 35 unilateral (16.7%)). 99.5% patients had V4 VAH and 56.0% (28/50) V1-V3 VAH. Among 210 BAH, there are 74 patients (mean age 64 years, average 25-91 years, 44 males) with a diagnosis of acute cerebral infarction (ACI). The males were predominant in ACI (59.5% in males vs 40.5% in females, P = 0.021). The frequency of BAH was detected in 74 (2.2%) among 3 294 ACI patients. As a relatively rare vascular abnormality, BAH has always unilateral or bilateral FTP and V4 VAH.

Persistent primitive trigeminal artery: analysis of anatomical characteristics and clinical significances

The purpose of this study was to evaluate the classification of persistent primitive trigeminal artery (PPTA) based on computed tomography (CT) angiography, magnetic resonance (MR) angiography, and cerebral angiography and to review the clinical significance. Images obtained by CT angiography performed between January 2011 and August 2013, MR angiography between January 2005 and January 2013, and cerebral angiography between January 2003 and November 2012 were analyzed for the presence of a PPTA. The diagnostic criterion for a PPTA was an artery that arises from the cavernous internal carotid artery and then joins the basilar artery (BA). We classified each PPTA by two different methods. First, the PPTA was classified as type 1, 2, 3, or 4 according to Weon et al.'s classification. Second, the classification of the PPTA was also made according to Salas et al.'s proposal, as a medial or lateral type. Eighteen of 8,900 patients (0.2%) had a PPTA. Of all 18 patients with a PPTA, nine were classified as type 1, two as type 2, six as type 3, and one as type 4. Seventeen PPTAs were a lateral type, and one was a medial type. Regarding the degree of BA hypoplasia, no hypoplasia was seen in six cases, moderate hypoplasia was identified in six cases, and severe hypoplasia was seen in six cases. This study revealed four types of PPTA according to Weon et al.'s classification. The presence of a PPTA should be considered by both the clinician and the radiologist who interprets the CT angiography, MR angiography, and conventional angiograms.

Anatomical Variations in the Posterior Part of the Circle of Willis and Vascular Pathology in Bilateral Thalamic Infarction

Bilateral paramedian thalamic infarction is a rare subtype of stroke the etiology of which still remains undetermined in many patients. From a computed tomography (CT)/magnetic resonance imaging report database, we identified and analyzed 48 patients with bilateral paramedian thalamic infarction on diffusion-weighted imaging. Vascular pathologies were noted on CT angiography (CTA)/magnetic resonance angiography (MRA) and the P1 segments of the posterior cerebral artery (PCA) described as normal, hypoplastic, or absent. Vascular imaging revealed top of the basilar artery (BA) occlusion in 6 (12.5%), BA occlusion in 4 (8.3%), BA stenosis in 1 (2.1%), and BA hypoplasia in 3 (6.3%), PCA occlusion in 4 (8.3%), and PCA stenosis in 4 (8.3%) patients. In 18 (37.5%) patients, one or both P1 segments of the PCA were hypoplastic or absent. Patients with hypoplastic/absent P1 segments were more likely to have exclusively bilateral paramedian thalamic lesions (P < .001). An embolic source could be identified in 25 (55.6%) patients; there were no significant differences between both groups. Vascular imaging is useful to determine underlying vascular pathologies and may support the diagnosis of small vessel disease in those patients with isolated bilateral paramedian thalamic infarction, hypoplastic/absent P1 segment of the PCA, and lack of vascular pathology.

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.

Posterior circulation ischemia in patients with fetal-type circle of Willis and hypoplastic vertebrobasilar system

Little attention has been given to the fetal-type posterior circle of Willis (FTP) in the literature; also symptomatic basilar artery (BA) hypoplasia has been rarely reported. We aimed to illustrate that the association of a hypoplastic vertebrobasilar system (VBS) with the FTP may lead to posterior circulation ischemia. Magnetic resonance imaging and three-dimensional time-of-flight magnetic resonance angiography were performed in 88 consecutive patients with ischemic stroke or TIA in the VBS. Thirteen patients were identified with either stroke or TIA in the context of a hypoplastic VBS and a fetal origin of the posterior cerebral arteries. All patients had unilateral or bilateral FTP, hypoplastic BA and at least one hypoplastic vertebral artery. Transcranial color-coded duplex revealed decreased flow velocity and increased pulsatility index along the BA. A hypoplastic VBS may be accompanied by the FTP and its simultaneous occurrence can predispose to ischemic events in the posterior circulation.

A case report of intracranial vertebral-basilar artery hypoplasia presenting with episodic dizziness

Basilar artery hypoplasia (BAH) is usually accompanied with unilateral vertebral artery hypoplasia (VAH); however, BAH with bilateral VAHs composing vertebral-basilar artery hypoplasia (VBAH) is indeed a rare curiosity. A 61-year-old woman presented with episodic dizziness for ten years. It accompanied with headache, bilateral tinnitus and blurred vision. Time-of-flight magnetic resonance angiogram with T2 true fast imaging in steady state precession confirmed the VBAH, rather than a stenosis. Symptoms subsided after daily oral aspirin and life-style change has been recommended for three months. The following one year was uneventful, and hearing improved. Finally, we conclude that the episodic dizziness with sensori-neural hearing impairment might attribute to the VBAH. It appears that life-style change was the main therapy and the antiplatelet was simply a supplementary one.

Segmental hypoplasia of the basilar artery: a case report and review of literature

The anomalies of the basilar artery are rare when compared with those ones pertaining to the circle of Willis vessels. Partial duplication or fenestration is rather common (0.6% to 1.8% in the angiographic descriptions); on the other hand, other anomalies, including complete duplication, hypoplasia and aplasia are exceptional. A rare case of segmental hypoplasia of the basilar artery in a 49-year-old man with transient vertebrobasilar (VB) ischemia, explored by magnetic resonance imaging (MRI) and digital angiography (DA), is reported. The embryology, the clinical relevance and the magnetic resonance findings of this arterial anomaly are discussed, with a review of other six reported cases. The appearance of a segmental aplasia was suggested in our case by MRI, and successively confirmed not only by time-of-flight MR-angiography (TOF-MRA) but also by DA. Only ultrathin-slice T2-weighted (w) images revealed the real finding of basilar artery (BA) hypoplasia; this sequence, not employed in previously reported cases, is mandatory to allowing a clear differential diagnosis between BA aplasia and hypoplasia. In conclusion, segmental hypo-aplasia of the BA is an exceptional embryological anomaly. This anomaly may be of clinical importance, and it should be considered among the potential causes of vertebrobasilar insufficiency in young adults. These cases should be investigated by MR and MRA; we stress the importance of ultrathin slice T2-weighted sequences in order to discriminate between aplasia and hypoplasia.

Association Between Basilar Artery Hypoplasia and Undetermined or Lacunar Posterior Circulation Ischemic Stroke

The aim of the current study was to determine the prevalence of basilar artery hypoplasia (BAH) and to evaluate whether BAH is a possible risk factor for posterior circulation stroke (PCS). Basilar artery diameter was assessed by MRI in 685 consecutive ischemic stroke patients. BAH frequency, defined as a diameter <2 mm, was measured and compared between anterior circulation stroke and PCS groups. Thirty-seven patients had BAH (5.2%): 15 of 195 (7.7%) in PCS and 22 of 490 (4.5%) in anterior circulation stroke (P=0.2). In undetermined or lacunar stroke patients, BAH frequency was higher in PCS than in anterior circulation stroke (14/97, 14.4% vs 10/216, 4.6%; P=0.005). National Institutes of Health Stroke Scale score was <4 in 65%. Localization of stroke was predominant in pons or cerebellar territories (71.4%). Half of PCS and BAH patients showed small pontic-penetrating arteries infarcts. Our study suggests that BAH is associated with PCS in lacunar or undetermined stroke. Patients often had minor stroke and infarctions that were usually small and frequently located in pontine-penetrating artery territories.

Radiologic Importance of a High-Resistive Vertebral Artery Doppler Waveform on Carotid Duplex Ultrasonography

The appearance of the vertebral artery (VA) waveform on a pulsed Doppler examination performed during standard carotid duplex ultrasonography (CDU) may suggest vertebrobasilar disease. We sought to determine the radiographic importance of high-resistive (HR) pulsed Doppler VA waveforms seen on CDU. The Noninvasive Vascular Laboratory database was queried for CDU studies noting the HR VA Doppler signal. Studies with unilateral or bilateral HR and antegrade VA waveforms with correlative neuroimaging studies within 60 days were included. Imaging reports were reviewed to determine the following: (1) a normal VA; (2) at least moderate distal VA or basilar artery (BA) stenosis, occlusion, or dissection; (3) a congenitally diminutive VA; or (4) other abnormalities. Of 1338 studies with 1 or more HR VA waveforms, 79 studies met all inclusion criteria (n = 157 arteries) and had adequate correlative neuroimaging. There were 90 HR VAs, and HR waveforms were equally distributed between right and left sides. The mean peak systolic velocity of HR versus low-resistive (LR) VAs was 51.7 versus 63.6 cm/s (P = .04); the mean end-diastolic velocity of HR versus LR VAs was 4.6 versus 17.3 cm/s (P < .001); and the resistive index of HR versus LR VAs was 0.92 versus 0.73 (P < .001). Of all HR VAs, 18.9% were normal; 38.9% had distal vertebrobasilar stenosis or occlusion; 35.6% were congenitally diminutive; and 6.7% had other abnormalities (proximal stenosis, excessive tortuosity, fibromuscular dysplasia, and BA hypoplasia). The finding of an HR spectral Doppler signal in the VA was associated with major vertebrobasilar disease (46% of cases) and should prompt additional neuroimaging in the appropriate clinical situation.

Epilepsy in Ehlers-Danlos syndrome.

Ehlers-Danlos syndrome (EDS) is a complex hereditary connective tissue disorder infrequently reported in association with epilepsy. Seven patients with ages ranging from 28 to 70 years with EDS and epilepsy are described. Case review of clinical and diagnostic data. Two patients had occipital horn syndrome (EDS type IX) and partial seizures of probable supplementary motor area origin. Of these two, one had an area of frontal gliosis and was able to abate his seizures by hyperextending his neck; the other had a Dandy Walker malformation and also had pseudoseizures. The third patient of the series had complex partial seizures, pain asymbolia, and basilar artery hypoplasia. The fourth had ictal aphasia, left hemispheric hypotrophy, and distal right arm and left leg atrophy. The fifth patient had focal seizures, a venous parietal angioma, hyperekplexia, nocturnal head oscillations (jactatio capitis nocturna), monoclonal gammopathy-associated neuropathy, and Tourette syndrome. The sixth had affective illness, chronic fatigue, and complex partial seizures with autoscopic phenomena after intracranial bleed. The seventh patient had a previous stroke, peripheral neuropathy, and grand mal seizures. EDS may be accompanied by congenital or acquired central nervous system disorders and epilepsy. Additional neurologic conditions that are unrelated to EDS may be present.

MRI of basilar artery hypoplasia associated with persistent primitive trigeminal artery

We report three patients with persistent trigeminal arteries, in all of whom the proximal basilar artery was hypoplastic. We draw attention to this common observation, which should not be mistaken for acquired narrowing.

MRI of basilar artery hypoplasia associated with persistent primitive trigeminal artery

MRI of basilar artery hypoplasia associated with persistent primitive trigeminal artery