Vertebral Artery Hypoplasia 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.

Anatomy of vertebral artery hypoplasia and its relationship with clinical implications: a systematic review and meta-analysis of prevalence.

The vertebral artery (VA) is a vital branch of the subclavian artery, coursing through the transverse foramina of the cervical vertebrae, and playing a crucial role in irrigating the posterior region of the arterial cerebral circle, also known as the Polygon of Willis. Among the various possible alterations that can affect the VA, vertebral artery hypoplasia (HAV) emerges as a significant variant. This study aims to discern the anatomical features of HAV and its correlation with the clinical conditions of the posterior cerebral circulation. The databases Medline, Scopus, Web of Science, Google Scholar, CINAHL, and LILACS were searched until January 2024. Two authors independently performed the search, study selection, and data extraction. Methodological quality was evaluated with an assurance tool for anatomical studies (AQUA). Pooled prevalence was estimated using a random effects model. A total of 24 studies met the established selection criteria, with a total of 8847 subjects. In this study, 6 articles were included for the meta-analysis with a total of subjects. The average prevalence of VAH reported in each study was 11% (95% CI 10-12%); the studies had a heterogeneity of 41% based on the funnel plot and a low risk of bias. The prevalence of VAH is low, but in the presence of this condition, the changes are mainly in diameter rather than morphological. If it is present, some clinical safeguards must be taken to avoid complications such as stroke.

Vertebral artery hypoplasia and hemodynamic impairment in transient global amnesia: a case control study.

The aetiology of transient global amnesia (TGA) is still a matter of debate. Besides ischemia of the mesial temporal lobe including the hippocampus, migraine-like mechanisms, epileptic seizures affecting mnestic structures, or venous congestion in the (para) hippocampal area due to jugular vein insufficiency have been discussed. We assessed the diameters of the intracranial arteries of TGA patients compared to controls to identify differences that support the hypothesis of reduced hippocampal perfusion as a pivotal factor in the pathophysiology of TGA. We reviewed magnetic resonance imaging time of flight angiographies (TOF-MRA) that were acquired during in-patient treatment of 206 patients with acute TGA. The diameters of the vertebral artery (VA) in the V4 segment, the proximal basilar artery, and the internal carotid arteries were measured manually. We compared the findings with TOF-MRA images of an age and sex matched control group of neurological patients without known cerebrovascular pathology. In TGA patients the diameter of the right VA was significantly (p < 0.01) smaller compared to controls (2.09 mm vs. 2.35 mm). There were no significant differences in the diameters of the other vessels. Only the fetal variant of the posterior cerebral artery was slightly more common in TGA. The smaller diameter (hypoplasia) of the right VA supports the hypothesis of a contribution of hemodynamic factors to the pathophysiology of TGA. The fact that hypoplasia represents a congenital condition might be the explanation why previous studies failed to find an increased rate of the classical (acquired) vascular risk factors.

Study on the Correlation Between Cerebral Vascular Variation and Hypertension

Abstract OBJECTIVE To investigate the association between cerebral vascular variation and hypertension in adults. METHODS Using a cross-sectional study, the current and retired employees of Kailuan Group who participated in the physical examination of Kailuan General Hospital and underwent magnetic resonance examination in 2020–2022 were taken as the observation objects, and a total of 1,029 people finally met the inclusion and exclusion criteria. The observation objects were divided into 4 groups: no cerebral vascular variation, only vertebral artery hypoplasia (VAH), only incomplete posterior Circle of Willis (ipCoW), and combined variations (VAH + ipCoW). Binary logistic regression models were used to explore the effects of different types of cerebral vascular variation on hypertension. RESULTS The mean age of the study population was 55.2 ± 11.4 years. The percentages in no cerebral vascular variations, VAH only, ipCoW only, and combined variations groups were 21.1%, 11.5%, 46.8%, and 20.6%, respectively. Using hypertension as the dependent variable and cerebral vascular variation type as the independent variable, and adjusting for multiple confounders, the results showed that the presence of both VAH and ipCoW was positively associated with hypertension risk (OR = 2.410, 95% CI = 1.401–4.146). Stratified analysis showed that the association was more pronounced in people younger than 55 (OR = 4.437, 95% CI = 1.891–10.406), whereas no significant association was found in people older than 55 (P &amp;gt; 0.05). CONCLUSIONS There is a positive correlation between cerebral vascular variation and hypertension, and this association is predominantly observed in the younger population.

Embolization of an Intracranial Vertebral Artery Aneurysm via the Deep Cervical Artery.

Treatment of vertebral artery aneurysms can be challenging due to the unusual vascular anatomy or unfeasibility of traditional endovascular techniques. We describe a novel approach for endovascular treatment of a ruptured intracranial vertebral artery aneurysm with bilateral vertebral artery occlusions and hypoplasia of the posterior communicating arteries. Successful coil embolization was performed using a collateral pathway for microcatheterization via anastomosis between the deep cervical artery and the vertebral artery. This case report highlights a novel alternative endovascular treatment approach for vertebrobasilar aneurysms in case of a poor vascular status with occlusion or lack of traditional endovascular access routes.

The association between vertebral artery hypoplasia and fetal-type variants of the posterior cerebral artery with imaging findings among patients with posterior circulation stroke: A single-center cross-sectional study.

The present study investigated the correlation between vertebral artery hypoplasia and fetal-type variations of posterior cerebral arteries with stroke patterns and imaging findings in individuals with posterior circulation ischemic stroke. In this cross-sectional study, patients with symptoms of acute ischemic stroke in the posterior circulation system referred to Ghaem Hospital in Mashhad between 2016 and 2022 were investigated. Demographic data, including age, gender, systemic diseases, history of previous stroke or transient ischemic attacks, and clinical manifestations of patients, were recorded using questionnaires and checklists from patient files. The results of imaging studies, including magnetic resonance imaging and computed tomography angiography, were also recorded. The obtained data were analyzed by SPSS statistical software. Among 974 patients suffering from posterior circulation ischemic stroke, 155 patients with an average age of 60.44 ± 13.95 years were included in the study, out of which 97 patients (62.6%) were male. Unilateral vertebral artery hypoplasia on the right, left, and bilateral hypoplasia was present in 67 (43.2%), 35 (22.6%), and 5 (3.2%) patients, respectively. There were complete unilateral fetal origin on the right in 38 (24.5%), complete unilateral on the left in 12 (7.7%), partial unilateral on the right in 12 (7.7%), partial unilateral on the left in 6 (3.9%), complete bilateral in 14 (9%), and partial bilateral in 8 (5.2%) patients. There was no significant relationship between vertebral artery hypoplasia and PCA fetal-type variants with different ischemia locations and infarct patterns (p > 0.05). Also, there was no significant relationship between the age and gender of patients with ischemia location and infarct pattern (p > 0.05). Despite previous evidence showing a relation between vertebral artery hypoplasia and PCA fetal-type variants as risk factors for PC stroke, the present study did not establish a significant correlation between these factors and the location of ischemia and infarct patterns.

Acoustic evoked potentials characteristics in patients with vertebral artery hypoplasia and posterior circulation stroke

Background/Aim. Acoustic evoked potentials (AEPs) represent an electrophysiological method used in diagnosing pathological changes of the brain stem (BSt), the acoustic nerve (its peripheral and central part), in patients in coma, in the confirmation of cerebral death, etc. The response includes seven negative waves which are generated in the structures of the BSt vascularized by the arteries of the posterior circulation. However, in everyday practice, due to their constancy, the first five waves are followed. The vertebral artery hypoplasia (VAH) is assumed to affect the AEPs finding. The current definition of VAH includes the criterion that the diameter of the blood vessel is ? 2 mm and that the ratio of the diameter of the left and right vertebral artery is ? 1 : 1.7. VAH is found in 5.3% of cases of the total population and its presence increases the risk of posterior circulation stroke (PCS). The aim of this study was to show a higher frequency of pathological findings of AEPs in patients with VAH and PCS and demonstrate the characteristics of AEP in that group of patients. Methods. This prospective study included 163 patients diagnosed with PCS over a period of two years. Computed tomography (CT) and magnetic resonance (MR) imaging (MRI) established the diagnosis of PCS. Suspicion of VAH was found by Color Doppler ultrasonography and confirmed by CT and MR angiography. All patients underwent AEPs testing. Wave amplitudes and interwave latencies (IWL) were monitored. Results. There was no statistically significant difference between gender (?2 = 1.823; p = 0.176) and age in relation to VAH (p = 0.815). A statistically significant greater number of patients with multiple PCS had a positive VAH finding (VAH group, 42.3%) compared to those without VAH (noVAH group, 26.6%) (?2=4.278; p=0.038). A statistically significant greater number of pathological AEPs was found in the group of patients with PCS and VAH (?2 = 4.899; p = 0.026). A statistically significant IWL change accompanied by low amplitude waves in the VAH group has been determined (?2 = 4.465; p = 0.034). Conclusion. The distribution of VAH is not gender- or age-related. The frequency of pathological AEPs findings (presence of associated changes in wave amplitudes and prolonged IWL) is statistically significantly higher in patients with VAH and PCS.

Evaluation of intracranial atherosclerotic disease risk factors in patients with acute ischemic stroke

Background &amp; Objective: Intracranial atherosclerotic disease (ICAD) is a prevalent cause of ischemic stroke and is related to recurrent strokes. In this study, we aim to identify the ICAD rate and establish the risk factors in patients with acute ischemic stroke (AIS) in our population in Turkey. Methods: Eight hundred sixty-two patients diagnosed with AIS in our tertiary centre between 01-01.2019 and 01.01.2021 were retrospectively included in this study. Results: We detected ICAD in 172 (20%) patients. While the independent risk factors of anterior ICAD were hypertension and diabetes mellitus, the risk factors of posterior ICAD were advanced age, diabetes mellitus, hyperlipidaemia and vertebral artery hypoplasia. There were more frequent posterior ICAD. Conclusion: There was difference in the risk factors for anterior ICAD and posterior ICAD in this Turkish study.

The Prevalence and Impact of Vertebral Artery Hypoplasia on Cerebral Hemodynamics

AbstractBackgroundVertebral artery hypoplasia (VAH) is an anatomical variation that may be associated with lower cerebral blood flow. We demonstrated the prevalence of VAH to be approximately 26% in a pilot study of healthy adults (n = 39). The purpose of this study was to expand on these findings by determining the prevalence of VAH and its impact on cerebral hemodynamics in a larger sample size of middle‐aged and older adults.MethodA total of 550 participants (66 ± 9 years; 346 females) underwent 4D flow MRI scans to evaluate the internal carotid arteries (ICA), vertebral arteries, and basilar artery. VAH+ (positive for VAH) was determined from the 4D flow MRI scans using both diameter (&lt;2.5 mm) and flow (&lt;47 mL/min).ResultWe identified 152 participants as VAH+ (prevalence of 28%). The prevalence of VAH+ was similar between females (n = 95; 27%) and males (n = 57; 28%). VAH predominantly occurred in the right vertebral artery (n = 102; 67%). As expected within VAH+ participants, the hypoplastic vertebral artery diameter was smaller (2.0±0.2 mm vs. 2.8±0.5 mm; p&lt;0.001), blood flow was lower (29±10 ml/min vs. 100±44 ml/min; p&lt;0.001), and pulsatility index was higher (1.8±0.6 a.u. vs. 1.3±0.3 a.u.; p&lt;0.001) compared to the contralateral artery. There were no differences in ICA diameter (p = 0.875), blood flow (p = 0.553) or pulsatility index (p = 0.984) between VAH+ and no VAH. When evaluating the basilar artery, the diameter was smaller (2.7±0.4 mm vs. 2.8±0.4 mm; p = 0.037) with lower blood flow (105±35 ml/min vs. 116±37 ml/min; p&lt;0.001) in VAH+ compared with no VAH. Males with VAH+ had higher basilar artery pulsatility index compared with males with no VAH (1.4±0.4 a.u. vs. 1.2±0.3 a.u.; p = 0.004), but this was not apparent in females (p = 0.544). When comparing global cerebral blood flow, there was a trend for lower flow in VAH+ compared with no VAH (p = 0.096).ConclusionWe demonstrated VAH prevalence to be around 28%, with similar prevalence in both males and females. VAH was associated with impaired regional flow and with elevated basilar artery cerebral pulsatility in males.

Abnormal flow pattern of low wall shear stress and high oscillatory shear index in spontaneous vertebral artery dissection with vertebral artery hypoplasia.

Spontaneous vertebral artery dissection (sVAD) might tend to develop in vertebral artery hypoplasia (VAH) with hemodynamic dysfunction and it is crucial to assess hemodynamics in sVAD with VAH to investigate this hypothesis. This retrospective study aimed to quantify hemodynamic parameters in patients with sVAD with VAH. Patients who had suffered ischemic stroke due to an sVAD of VAH were enrolled in this retrospective study. The geometries of 14 patients (28 vessels) were reconstructed using Mimics and Geomagic Studio software from CT angiography (CTA). ANSYS ICEM and ANSYS FLUENT were utilized for mesh generation, set boundary conditions, solve governing equations, and perform numerical simulations. Slices were obtained at the upstream area, dissection or midstream area and downstream area of each VA. The blood flow patterns were visualized through instantaneous streamline and pressure at peak systole and late diastole. The hemodynamic parameters included pressure, velocity, time-averaged blood flow, time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), endothelial cell action potential (ECAP), relative residence time (RRT) and time-averaged nitric oxide production rate (TARNO). Significant focal increased velocity was present in the dissection area of steno-occlusive sVAD with VAH compared to other nondissected areas (0.910 m/s vs. 0.449 vs. 0.566, p < 0.001), while focal slow flow velocity was observed in the dissection area of aneurysmal dilatative sVAD with VAH according to velocity streamlines. Steno-occlusive sVAD with VAH arteries had a lower time-averaged blood flow (0.499 cm3/s vs. 2.268, p < 0.001), lower TAWSS (1.115 Pa vs. 2.437, p = 0.001), higher OSI (0.248 vs. 0.173, p = 0.006), higher ECAP (0.328 Pa-1 vs. 0.094, p = 0.002), higher RRT (3.519 Pa-1 vs. 1.044, p = 0.001) and deceased TARNO (104.014 nM/s vs. 158.195, p < 0.001) than the contralateral VAs. Steno-occlusive sVAD with VAH patients had abnormal blood flow patterns of focal increased velocity, low time-averaged blood flow, low TAWSS, high OSI, high ECAP, high RRT and decreased TARNO. These results provide a good basis for further investigation of sVAD hemodynamics and support the applicability of the CFD method in testing the hemodynamic hypothesis of sVAD. More detailed hemodynamic conditions with different stages of sVAD are warranted in the future.

GSI CTA evaluation of the vertebrobasilar artery in normal adults at high altitude.

Vascular geometry is influenced by several factors during its growth and development. Here, we compared the differences in vertebrobasilar geometry among residents of a plateau region at different altitudes and investigated the relationship between vascular geometry and altitude. Data of some adults in the plateau region who experienced vertigo and headache as the main symptoms but had no evident abnormalities found during imaging examination were collected. They were divided into three groups based on an altitude gradient: group A (1,800-2,500 masl), group B (2,500-3,500 masl), and group C (over 3,500 masl). They underwent head-neck energy-spectrum computed tomography angiography with a gemstone spectral imaging scanning protocol. The following indices were observed: (1) vertebrobasilar geometric configurations (walking, tuning fork, lambda, and no confluence), (2) vertebral artery (VA) hypoplasia, (3) the bending number of bilateral VA intracranial segment, (4) length and tortuosity of the basilar artery (BA), and (5) anteroposterior (AP)-mid-BA angle, BA-VA angle, lateral-mid-BA angle, and VA-VA angle. Of the 222 subjects, 84 of them were included in group A, 76 in group B, and 62 in group C. The number of participants in walking, tuning fork, lambda, and no confluence geometries was 93, 71, 50, and 8, respectively. As altitude increased, the tortuosity of the BA also increased (1.05 ± 0.06 vs. 1.06 ± 0.08 vs. 1.10 ± 0.13, P = 0.005), as did the lateral-mid-BA angle (23.18° ± 9.53° vs. 26.05° ± 10.10° vs. 31.07° ± 15.12°, P = 0.007) and the BA-VA angle (32.98° ± 17.85° vs. 34.51° ± 17.96° vs. 41.51° ± 19.22°, P = 0.024). There was a relatively weak positive correlation between the altitude and the tortuosity of the BA (rs = 0.190, P = 0.005), the lateral-mid-BA angle (rs = 0.201, P = 0.003), and the BA-VA angle (rs = 0.183, P = 0.006) which showed a significant difference. Compared with groups A and B, there were more multibending groups and fewer oligo-bending groups in group C (P < 0.001). There was no difference found in the vertebral artery hypoplasia, actual length of the BA, VA-VA angle, and AP-mid-BA angle among the three groups. As the altitude increased, the tortuosity of the BA and the sagittal angle of the vertebrobasilar arterial system also increased. The increase in altitude can lead to changes in vertebrobasilar geometry.

Multidetector computed tomography evaluation of origin, V2 segment variations and morphology of vertebral artery.

The current study aimed to determine the origin of vertebral artery (VA) on both sides and the levels of entry into respective foramen transversarium (FT), to evaluate possible effects of sex on the entry levels, and to investigate the frequency of VA dominance and VA hypoplasia based on the VA V2 segment. For this study, archived images of patients undergoing multidetector computed tomography (MDCT) examination of the chest and headneck for various reasons at Gaziantep University Medical Faculty Hospital were reviewed retrospectively. Three-dimensional reconstructions were performed for a total of 644 VA images from 322 patients using Horos software, and VA origin, the level of entry to FT and transverse diameters of both VA and FT were measured at the point of entry. It was found that, among males, the VA originated from the truncus brachiocephalicus on the right side in only 1 patient and from the aortic arch in 2 patients on the left side. Left VA emerging from the aortic arch was observed in 2 females. The right VA was found to enter the FT at C3 in 1 male, at C4 in 6 patients (5 males, 1 female), at C5 in 19 patients (3 males, 16 females), and at C6 in 300 patients (141 males, 159 females). The left artery entered the FT at C5 in 23 patients (9 males, 14 females) and at C6 in 298 patients (141 males, 157 females). Looking at the relationship between variations of VA origin and the levels of entry to the FT, it was observed that only one of the left VAs originating from the arcus aorta entered the FT at C6 and at C5 in all others. On the right side, there was only one VA originating from the truncus brachiocephalicus, which entered the FT at C3. Of the remaining 248 VAs originating from the subclavian artery, 5 VAs entered the FT at C4, 14 VAs at C5 and 229 VAs at C6. The measurements of VA diameters showed right VA hypoplasia in 14 patients and left VA hypoplasia in 17 patients. Also, the right VA dominance was found in 110 patients and the left VA dominance in 128 patients. A moderate, positive correlation was observed between VA and FT diameters in both sides. A regression analysis showed that a 1 mm change in the right VA diameter was associated with a 75% change in the FT diameter and a 1 mm change in the left VA diameter caused a 72% change in the FT diameter. An understanding of VA variations and FT morphometry is crucial for informed clinical practice. This will clearly affect the success rates of physicians in the diagnosis and treatment of pathologies involving cervical region. The presence of any VA variation in a patient should be investigated on computed tomography or magnetic resonance imaging images prior to surgery.

Teaching NeuroImages: Vertebral artery compression by head tilt around the roll axis diagnosed by transcranial Doppler

A 59-year-old man reported transient vertigo and diplopia during leftward head tilt around the roll axis. Neurologic examination was unremarkable with the head erect or tilted. Magnetic resonance angiography of the head and neck showed hypoplasia of the right vertebral artery (figure 1). Transcranial Doppler waveform was monitored during leftward head tilt. The left vertebral artery flow velocity decreased with tilt, and abruptly increased after returning to erect posture (figure 2). Vertebral artery can be stretched or kinked by head rotation or tilt,1,2 typically at the C1-2 level.1 Transcranial Doppler could be helpful in diagnosis of such cases.

Role of CT Angiography in Detection of Extracranial Carotid and Vertebral Artery Disease in Patients With Acutely Ruptured Intracranial Aneurysms

Introduction: Computed tomography (CT) and CT angiography are standard imaging modalities for suspected acute intracerebral hemorrhage due to ruptured intracranial aneurysms. In this clinical setting, several protocols of computed tomography and CT angiography may be implemented. The standard CT angiography protocol is limited to intracranial vessels. The extended protocol may also include carotid and vertebral arteries and the aortic arch.Objective: To define the CT angiography role in detection of extracranial carotid and vertebral artery disease and clinical significance of this method for patients with suspected acute intracerebral hemorrhages due to ruptured intracranial aneurysms.Materials and methods: The study included 275 neurosurgical patients with acute nontraumatic intracranial hemorrhages due to ruptured intracranial aneurysms who were treated in Scientific Research Institute – Ochapovsky Regional Clinical Hospital No. 1 (Krasnodar, Russian Federation) from September 2017 to August 2020. Computed tomography and CT angiography were performed in all patients. The scanned area included both intracranial and extracranial arteries (an arch-to-vertex angiogram) to detect extracranial carotid and vertebral artery diseases such as stenoses, occlusions, tortuosity, and hypoplasia.Results: Atherosclerosis of internal carotid and vertebral arteries was diagnosed in 95 patients (34.5% of the total number of patients included in the study). In 13 (4.7%) patients these stenoses were hemodynamically significant. We identified a high frequency of tortuous carotid and vertebral arteries (122 cases, 44.3%) and vertebral artery hypoplasia (59 cases, 21.5%). The carotid and vertebral artery stenoses and congenital anomalies of vertebral arteries (however, not of carotid arteries) were associated with a higher incidence of unfavorable outcomes after endovascular treatment of intracranial aneurysms.Conclusions: The optimal CT angiography protocol for acute nontraumatic intracranial hemorrhage should focus on the arteries of the head and neck (up to the aortic arch). This protocol shows higher detection rate of concomitant anomalies of carotid and vertebral arteries. These findings are important for planning and successful performance of endovascular treatment for intracranial aneurysms.

Morphometric evaluation of cerebellar lobules in individuals with unilateral vertebral artery hypoplasia.

Vertebral arteries (VAs) provide blood circulation to the posterior fossa in general and are the main blood supply of the posterior fossa structures of the brain. Our aim in this study is to analyze the segmental volumetric values of cerebellar structures with the voxel-based volumetric analysis system in individuals with unilateral vertebral artery hypoplasia. In this retrospective study, segmental volumetric values/percentile ratios of cerebellar lobules were calculated using 3D fast spoiled gradient recall acquisition in steady-state (3D T1 FSPGR) MRI sequence images of the brain in individuals with unilateral vertebral artery hypoplasia (VAH) and in those without bilateral VAH and any symptoms of vertebrobasilar insufficiency as the control group was evaluated in volBrain ( http://volbrain.upv.es/ ). The VAH group consisted of 50 (19 males/31 females) and the control group had 50 (21 males/29 females) individuals. The cerebellar lobule III, IV, VIIIA and X total volumes and the cerebellar lobule I-II, III, IV, VIIIA and X gray matter volumes were lower in the hypoplastic side than the non-hypoplastic cases and also than the contralateral side of the hypoplastic cases in the VAH group. In addition, it was found that that lobules IV and V had lower cortical thickness and lobules I-II had a higher coverage rate in the intracranial cavity in the hypoplastic side than the non-hypoplastic cases and also than the contralateral side of the hypoplastic cases (p < 0.05). In this study, it was found that cerebellar lobule III, IV, VIIIA, X total volumes and cerebellar lobule I-II, III, IV, VIIIA, X gray matter volumes in addition to lobule IV, V cortical thicknesses were low in individuals with unilateral VAH. Being aware of these variations and taking them into account during future volumetric studies on the cerebellum are very important.

Patološki nalaz slušnih evociranih potencijala kod pacijenata sa hipoplazijom vertebralne arterije udruženom sa moždanim udarom posteriorne cirkulacije

The aim of the paper was to determine clinical significance of pathological finding and characteristics of auditory evoked potentials (AEP) in patients with posterior circulation stroke caused by vertebral artery hypoplasia (VAH). The study enrolled 71 patients, 31 of them had posterior circulation stroke. The results of the examinations showed that pathological AEP finding was statistically significantly correlated with posterior circulation stroke (PCS) finding. Changes in AEP amplitude presented a prominent feature of stroke caused by vertebral artery hypoplasia and require further clinical investigations.

Successful subclavian artery stenting in a patient with subclavian steal syndrome associated with contralateral vertebral artery hypoplasia.

Successful subclavian artery stenting in a patient with subclavian steal syndrome associated with contralateral vertebral artery hypoplasia.

Association of Left Vertebral Artery Hypoplasia with Posterior Circulation Stroke and the Functional Outcome of Patients with Atrial Fibrillation-Related Cardioembolic Stroke.

A cardiogenic embolus could reach the posterior circulation through the right vertebral artery because of a relatively larger diameter in cases of left vertebral artery hypoplasia. Hence, we investigated whether left vertebral artery hypoplasia is associated with cardiac embolisms with atrial fibrillation in the posterior circulation and its functional outcomes. In this monocentric retrospective study, patients with acute cardioembolic stroke with atrial fibrillation were enrolled and underwent CT or neck MRA, which visualized the aortic arch and subclavian arteries. The laterality and size of vertebral artery hypoplasia were recorded. Posterior circulation stroke, basilar artery occlusion, and the functional outcomes after 3 months were investigated. This study included 407 patients; the patients with left vertebral artery hypoplasia experienced a higher rate of posterior circulation stroke (19 versus 73; 42.2% versus 20.2%; P = .001) and basilar artery occlusion (5 versus 10; 11.1% versus 2.8%; P = .005) than the patients without left vertebral artery hypoplasia. Multivariate analysis revealed that left vertebral artery hypoplasia showed an association with lower odds of achieving a good functional outcome 3 months after the stroke (OR = 0.4; 95% CI, 0.2-0.9; P = .027). Patients with cardioembolic stroke and left vertebral artery hypoplasia had posterior circulation stroke, basilar artery occlusion, and poor functional outcomes after 3 months.

Association of Vertebral Artery Hypoplasia and Vertebrobasilar Cerebrovascular Accident.

Background and Objectives: Vertebral artery hypoplasia (VAH) is a controversial risk factor for cerebral infarction. The aim of this study was to analyze the prevalence of vertebral artery hypoplasia and to evaluate its association with vertebrobasilar cerebrovascular accidents. Materials and Methods: The study was conducted in the Neurology Departments of the Republican Vilnius University Hospital from 2015 to 2020. Data of 742 subjects (133 patients with posterior circulation infarction or vertebral artery syndrome (PCI/VAS), 80 patients with anterior circulation infarction (ACI) and 529 control subjects with no symptoms of cerebrovascular accident) were analyzed. Ultrasound examination of the extracranial internal carotid and vertebral arteries (VA) was performed, risk factors were recorded. Results: The mean age of the subjects was 64.51 ± 13.02 years. In subjects with PCI/VAS the diameter of VA was smaller, and the prevalence of VAH was higher compared to those in subjects with ACI and in the control group. A higher degree of VAH in subjects younger than 65 years of age increased the risk of PCI/VAS. Subjects with non-dominant VA diameter of 2.7–2.9 mm had 2.21 times higher risk of PCI/VAS, subjects with non-dominant VA diameter of 2.5–2.6 mm had 2.36 times higher risk of PCI/VAS, and subjects with non-dominant VA diameter of 2.2–2.4 mm had 4.12 times higher risk of PCI/VAS compared with subjects with non-dominant VA diameter of ≥3 mm. Among patients with PCI/VAS those with VAH had lower rates of ischemic heart disease compared with patients with normal VA diameter. There was no difference in the rates of other risk factors between PCI/VAS patients with and without VAH. Conclusions: Vertebral artery hypoplasia is not a rare finding in individuals without symptoms of cerebrovascular accident, but more frequent in patients with vertebrobasilar cerebral infarction or vertebrobasilar artery syndrome. Vertebral artery hypoplasia can be considered a risk factor for posterior circulation infarction in subjects under 65 years of age.

Clinical Characteristics of Patients with Vertebral Artery Hypoplasia.

Vertebral artery hypoplasia (VAH) belongs to the relatively frequent Doppler ultrasonography (US) findings. However, its clinical significance remains controversial. This was a retrospective study analyzing clinical data of patients undergoing US because of cerebrovascular disease in a single academic neurology center. In the dataset of 2500 US examinations, 80 individuals with VAH (VA diameter < 2.0 mm) were identified (3.2% of all patients). Patients with significant vertebral artery asymmetry (SVAA, difference in VA diameters > 1.0 mm) (n = 80) and patients with normal VA diameter (n = 80) were also recruited. Clinical parameters including clinical signs and symptoms, concomitant diseases, imaging findings and the hospitalization outcome were compared between groups. The frequency of vertigo was highest in VAH group. Ischemic lesions of the cerebellum were found in 10% of VAH patients, 16% of SVAA patients and 5% of control subjects. Neurological deficits improved in over 60% of patients in each group, whereas ca. 30% of patients remained in a stable neurological status. The percentage of patients who deteriorated did not exceed 5% in any of the groups. The results of our study support a relatively high frequency of VAH. Our observations suggest coexistence of VAH with a higher frequency of neurological presentations associated with posterior arterial circulation of the central nervous system.