Wall Imaging for Unilateral Intracranial Vertebral Artery Hypoplasia with Three-dimensional High-isotropic Resolution Magnetic Resonance Images

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

PURPOSE

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Association between high-resolution magnetic resonance vessel wall imaging characteristics and recurrent stroke in patients with intracranial atherosclerotic steno-occlusive disease: A prospective multicenter study

BACKGROUND

High-resolution magnetic resonance vessel wall imaging (HRMR-VWI) is a promising technique for identifying intracranial vulnerable plaques beyond lumen narrowing. However, the association between HRMR-VWI characteristics and recurrent stroke remains uncertain.

AIMS

This study aimed to investigate the association between HRMR-VWI characteristics and recurrent ipsilateral stroke in patients with symptomatic intracranial atherosclerotic steno-occlusive disease (ICAS).

METHODS

This multicenter, observational study recruited first-ever acute ischemic stroke patients attributed to ICAS (>50% stenosis or occlusion) within 7 days after onset. Participants were assessed by multiparametric magnetic resonance imaging (MRI) including diffusion-weighted imaging, three-dimension time-of-flight magnetic resonance angiography, and three-dimensional T1-weighted HRMR-VWI. The patients were recommended to receive best medical therapy and were systematically followed up for 12 months. The association between HRMR-VWI characteristics and the time to recurrent ipsilateral stroke was investigated by univariable and multivariable analysis.

RESULTS

Two hundred and fifty-five consecutive patients were enrolled from 15 centers. The cumulative 12 month ipsilateral recurrence incidence was 4.1% (95% confidence interval (CI): 1.6-6.6%). Patients with recurrent ipsilateral stroke exhibited higher rates of intraplaque hemorrhage (IPH) (30.0% vs 6.5%) and eccentric plaque (90.0% vs 48.2%), and lower occurrence of occlusive thrombus (10.0% vs 23.7%). Plaque length (5.69 ± 2.21 mm vs 6.67 ± 4.16 mm), plaque burden (78.40 ± 7.37% vs 78.22 ± 8.32%), degree of stenosis (60.25 ± 18.95% vs 67.50% ± 22.09%) and remodeling index (1.07 ± 0.27 vs 1.03 ± 0.35) on HRMR-VWI did not differ between patients with and without recurrent ipsilateral stroke. In the multivariable Cox regression analysis, IPH (hazard ratio: 6.64, 95% CI: 1.23-35.8, p = 0.028) was significantly associated with recurrent ipsilateral stroke after adjustment.Conclusions:Our results suggest intraplaque hemorrhage (IPH) is significantly associated with recurrent ipsilateral stroke and has potential value in the selection of patients for aggressive treatment strategies.

DATA ACCESS STATEMENT

Data from this study are available and can be accessed upon request.

Percutaneous transluminal angioplasty and stenting vs aggressive medical management on stroke or intracranial atherosclerotic stenosis: a systematic review and meta-analysis

There are currently two main treatment strategies mainly for high-risk patients: percutaneous transluminal angioplasty and stenting (PTAS) and aggressive medical management (AMM). However, the choice between PTAS or AMM remains controversial for patients with stroke or intracranial atherosclerotic stenosis (ICAS). The investigators searched the PubMed, Web of Science, Embase, Scopus, and Cochrane library databases. Randomized controlled trial (RCT) comparing PTAS and AMM for patients with stroke or ICAS were selected. RevMan 5.3 was used to analyze the results and assess risk of bias. The primary endpoints are stroke and death within 30 days after enrollment, or ischemic stroke in the territory of the qualifying artery beyond 30 days, and entire follow-up endpoints. The secondary outcomes were the disabling or fatal stroke, and incidence of death within 3 years. Four studies, 989 patients were included in this article. The AMM group was superior in the entire follow-up endpoint (OR 0.56; 95% CI 0.40, 0.79). The AMM also better in primary endpoint within 30 days (OR 0.32; 95% CI 0.17, 0.61). There was no significant difference beyond 30 days (OR 1.08; 95% CI 0.63, 1.86). The remaining outcomes, such as stroke and death, were not significantly different (P > 0.05). This meta-analysis shows AMM is significantly more effective than PTAS in subjects with ICAS due to the high rate of periprocedural stroke (OR 0.32; 95% CI 0.17, 0.61) and stroke during the entire follow-up (OR 0.56; 95% CI 0.40, 0.79) associated with PTAS. Furthermore, PTAS offers no additional benefits over AMM beyond 30 days (OR 1.08; 95% CI 0.63, 1.86).

Black blood imaging of intracranial vessel walls

Traditional vascular imaging focuses on non-invasive cross-sectional imaging to assess luminal morphology; however, the vessel wall itself may be specifically involved in many diseases. Newer pulse sequences, and particularly black blood MRI of intracranial vessels, have brought a paradigm shift in understanding the pathophysiology of many vasculopathies. Black blood MRI of intracranial vessel walls can help in a range of pathologies with differing pathophysiology, including intracranial atherosclerosis, aneurysms, vasculitis and vasculopathy, moyamoya disease, dissection and vertebrobasilar hypoplasia. This review highlights how vessel wall imaging can contribute to the clinical diagnosis and management of patients with intracranial vascular pathology.

Endovascular recanalization for chronic symptomatic intracranial vertebral artery total occlusion: Experience of a single center and review of literature

OBJECTIVE

The optimal treatment of chronic symptomatic total occlusion of the intracranial vertebral artery (ICVA) remains undefined. We report a single-center experience of endovascular recanalization for patients with chronic symptomatic ICVA occlusion who were refractory to medical therapy.

METHODS

From Jan 2009 to Jan 2017, we retrospectively reviewed 14 consecutive patients presenting with recurrent symptoms attributed to the chronic ICVA occlusion. We searched previous literature using PubMed databases during the same period as comparison.

RESULTS

Eleven patients out of 14 presented initial symptoms to intervention less than 90days. The occlusion course was extrapolated on simultaneous two-vessel injection angiography or high-resolution MR imaging (HRMRI) in 13 cases. Nine patients had the occlusion beyond the origin of posterior inferior cerebellar artery (PICA) and 5 had the occlusion proximal to the PICA origin. The technical success rate of recanalization was 85.7% (12/14). Two patients (14.3%, 2/14) had peri-procedural complications: 1 developed TIA and 1 presented with perforator occlusion syndrome. Using the keyword-based search, we identified 6 studies at the same period. A total of 34 patients underwent recanalization with the successful recanalization rate at 94.1%, peri-procedural complication rate at 17.6% and mortality at 2.9%, respectively.

CONCLUSION

Our single-center study illustrated the feasibility and safety of ICVA recanalization. Great care should be taken as revascularization is of high risk. When patient selection, occlusion course and stage as well as neuroimaging evaluation are considered, endovascular recanalization may be a useful therapeutic modality.

Current Status and Future Perspective of Stenting for Symptomatic Intracranial Atherosclerotic Disease: A Meta-Analysis

The aim of this study was to evaluate the safety and effectiveness of percutaneous transluminal angioplasty and stenting (PTAS) for intracranial atherosclerotic disease (ICAD) by conducting a meta-analysis. Two independent observers searched PubMed, EMBASE, and Cochrane Library for relevant studies up to 31 December 2016. A meta-analysis was conducted using Review Manager 5.3. Three studies involving 581 cases were included. The meta-analysis indicated that any stroke (RR = 3.13; 95% CI: 1.80-5.42), ischemic stroke (RR = 2.15; 95% CI: 1.19-3.89), and intracranial hemorrhage (RR = 14.71; 95% CI: 1.96-110.48) within 30 days in medical therapy alone were lower compared with PTAS plus medical therapy, but there were no significant differences in any stroke and ischemic stroke beyond 30 days between the two groups. There were also no significant differences in any death and myocardial infarction between the two groups. This meta-analysis demonstrated that, compared with medical therapy alone, PTAS for ICAD had a high risk of complication, but most complications in PTAS group occurred within 30 days after the operation, and beyond 30 days the PTAS was not inferior compared with medical therapy alone. Further studies are needed to reduce the periprocedural complications and reappraise the PTAS.

Increased risk for posterior circulation ischaemia in patients with vertebral artery hypoplasia: A systematic review and meta-analysis

Introduction

Although several study protocols reported that vertebral artery hypoplasia can predispose to posterior circulation ischaemia, the role of vertebral artery hypoplasia in the risk of posterior circulation ischaemia still remains controversial. The aim of the present meta-analysis was to investigate the association of vertebral artery hypoplasia and posterior circulation ischaemia.

Patients and methods

We performed a systematic review and random effects meta-analysis of all eligible observational study protocols reporting prevalence rates of vertebral artery hypoplasia in patients with anterior circulation ischaemia and posterior circulation ischaemia.

Results

We identified eight study protocols including a total of 3875 acute ischemic stroke patients (mean age: 64.2 years, 61.3% males) and reporting a pooled prevalence of vertebral artery hypoplasia 18.6% (95%CI: 10.8-30.0%). In the overall analysis, a significantly higher probability of vertebral artery hypoplasia presence was found in posterior circulation ischaemia patients compared to patients with anterior circulation ischaemia (risk ratio = 2.12, 95%CI: 1.60-2.82, p < 0.001). In the subsequent sensitivity analysis, vertebral artery hypoplasia was again found to be significantly more prevalent in patients with posterior circulation ischaemia compared to anterior circulation ischaemia (risk ratio = 1.81, 95%CI: 1.58-2.06, p < 0.001), with no evidence of heterogeneity (I²= 0%, p for Cochran Q = 0.55) between included studies.

Discussion

The present report is a meta-analysis of retrospective observational study protocols, with all the inherent limitations of included studies. The heterogeneity on the reported rates of vertebral artery hypoplasia could be attributed to differences in population age, sex, race, imaging protocols and vertebral artery hypoplasia definition between included studies.

Conclusion

Our meta-analysis provides further evidence for a possible causal relationship between vertebral artery hypoplasia and cryptogenic posterior circulation ischaemia, an association which undoubtedly deserves further investigation in future prospective study protocols.

High-resolution Magnetic Resonance Vessel Wall Imaging for Intracranial Arterial Stenosis

OBJECTIVE

To discuss the feasibility and clinical value of high-resolution magnetic resonance vessel wall imaging (HRMR VWI) for intracranial arterial stenosis.

DATE SOURCES

We retrieved information from PubMed database up to December 2015, using various search terms including vessel wall imaging (VWI), high-resolution magnetic resonance imaging, intracranial arterial stenosis, black blood, and intracranial atherosclerosis.

STUDY SELECTION

We reviewed peer-reviewed articles printed in English on imaging technique of VWI and characteristic findings of various intracranial vasculopathies on VWI. We organized this data to explain the value of VWI in clinical application.

RESULTS

VWI with black blood technique could provide high-quality images with submillimeter voxel size, and display both the vessel wall and lumen of intracranial artery simultaneously. Various intracranial vasculopathies (atherosclerotic or nonatherosclerotic) had differentiating features including pattern of wall thickening, enhancement, and vessel remodeling on VWI. This technique could be used for determining causes of stenosis, identification of stroke mechanism, risk-stratifying patients, and directing therapeutic management in clinical practice. In addition, a new morphological classification based on VWI could be established for predicting the efficacy of endovascular therapy.

CONCLUSIONS

This review highlights the value of HRMR VWI for discrimination of different intracranial vasculopathies and directing therapeutic management.

Vertebral Artery Diameter and Flow: Nature or Nurture

BACKGROUND AND PURPOSE

In contrast with the carotid arteries, the vertebral arteries (VAs) show considerable variation in length, caliber, and vessel course. This study investigated whether the variation in diameter and flow characteristics of the VAs might be inherited.

METHODS

A total of 172 Italian twins from Padua, Perugia, and Terni (54 monozygotic, 32 dizygotic) recruited from the Italian Twin Registry underwent B-mode and pulsed-wave Doppler ultrasound assessment of their VAs. VA diameters, peak systolic velocity (PSV) and end diastolic velocity (EDV) were assessed at the level of a horizontal V2 segment. Univariate quantitative genetic modeling was performed.

RESULTS

Fourteen percent of the sample had VA hypoplasia. Within pair correlation in monozygotic twins was higher than in dizygotics (.552 vs. .229) for VA diameter. Age- and sex-adjusted genetic effect, under the most parsimonious model, accounted for 54.7% (95% CI: 42.2-69.1%) of the variance of VA diameter, and unshared environmental effect for 45.3% (95% CI: 30.9-57.8%). No heritability was found for the PSV of VA, but shared (34.1%; 95% CI: 16.7-53.7%) and unshared (65.9%; 95% CI: 45.9-83.1%) environmental factors determined the variance. EDV of VA is moderately genetically influenced (42.4%; 95% CI: 16.1-64.9%) and also determined by the unshared environment (57.6%; 95% CI: 34.7-83.7%).

CONCLUSIONS

The diameter of the VAs is moderately genetically determined. Different factors influence the PSV and EDV of VAs, which may highlight the complex hemodynamic background of VA flow and help to understand the vertebral flow anomalies found by ultrasound.

Wall thickening pattern in atherosclerotic basilar artery stenosis

Our aim was to investigate wall thickening (WT) pattern of atherosclerotic basilar artery stenosis with three-dimensional volumetric isotropic turbo spin echo acquisition (3D VISTA), and the relationship with clinical characteristics. Twenty consecutive patients with atherosclerotic basilar artery stenosis were prospectively enrolled. All cross-sectional slices on VISTA images of basilar arteries were assessed, and classified as eccentric or concentric WT. Clinical characteristics and degree of stenosis were compared between the patients with different wall WT pattern. Wall abnormalities were identified in 568 cross-sectional slices in basilar arteries of 20 patients including eccentric WT in 497 (87.5 %) slices, and concentric WT in 71 (12.5 %) slices. In 11 of 20 patients, all the cross-sectional slices (293 slices) showed eccentric WT. In 9 of 20 patients, the cross-sectional slices (275 slices) showed both eccentric WT (204 slices, 74.2 %) and concentric WT (71 slices, 25.8 %). No lesion showed only concentric WT. At the slices of maximum luminal narrowing sites, only one patient showed concentric WT. Symptomatic stenosis was more common in the patients with mixed WT (eccentric and concentric), compared to patients with only eccentric WT (100 vs 54.5 %, p = 0.038). Atherosclerotic basilar artery stenosis could show both eccentric and concentric WT based on each slice analysis. Concentric WT was found in near half of the patients, but tended to locate in minimal slices. No lesion was entirely concentric. Lesions with mixed WT (concentric and eccentric) might represent advanced atherosclerosis with high risk of ischemic event.