Ultrasound of the extracranial vertebral artery

Iatrogenic vertebral artery injury during catheter ablation treated using coil embolization

The internal jugular vein (IJV) is occasionally used for blood access during catheter ablation. Additionally, accidental injury of the vertebral artery during an IJV puncture is a rare complication that can result in catastrophic events, such as death. However, vascular access complications cannot be completely prevented despite the introduction of ultrasound-guided punctures. Here, we present a case of a patient with symptomatic paroxysmal atrial fibrillation that required catheter ablation.

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

Background and Aim

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.

Methods

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.

Results

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).

Conclusion

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.

Retrospective Study of Normal Variations in Vertebral Artery on Computed Tomography Angiography With Special Emphasis on Relevant Embryology

Background The vertebral arteries (VA) nourish the posterior cerebral circulation. Planning neck and cervical interventions like drilling and instrumentation, which involves VA manipulation, require an in-depth acquaintance with the normal and variant patterns encountered in the origin and course of the VA. Embryological events involved in forming these variant patterns can be correlated to their prior disposition in the lower vertebrate's understanding which becomes crucial while planning cervical interventions.  Study design This is a single-center, retrospective study.  Materials and methods The study involved 70 patients of both sexes and was done from September 2021 to February 2022 in the Department of Radiodiagnosis and Imaging at North Eastern Indira Gandhi Regional Institute of Health and Medical Sciences (NEIGRIHMS), Meghalaya, India. The CT angiographies were studied for variations of VA under V1 - from origin to entrance into the foramen transversarium (FT), V2 - part inside FT, V3 - from its exit from FT till it pierces the cranial dura mater, and V4 - intracranial part. Further, VA was observed for its origin, dominance, level of entry in FT, and any associated anomalies.  Results The VA was found mostly to be codominant. There was an opposite directional relationship between the basilar artery curvature and the dominance of VA. The association of ischemic events with hypoplastic VA was more on the left side (66.67%). Left VA originated from the aorta in 4.3% of subjects. One case presented a dual origin of VA. The abnormal origin of the LVA from the aorta showed a higher rate of abnormal entry into FT which was also found to be statistically significant.  Conclusion Our study identifies and documents the anatomical variations present in VA specific to the population of northeast India by CT angiography and thus provides a much-needed reference for the healthcare professionals working in the field of Head and Neck interventions by providing opportunities further to understand these patterns for better diagnostic and therapeutic outcomes.

Subtypes of the Completely Reversed Flow Waveform in Vertebral Artery Can Help to Differentiate Subclavian Artery Occlusion from Severe Stenosis

OBJECTIVES

To investigate the value of subtypes of completely reversed flow (CRF) waveform in vertebral artery (VA) on Doppler ultrasound in differentiation occlusion from severe stenosis of the ipsilateral proximal subclavian artery (SA).

METHODS

A total of 357 patients with CRF in the VA on Doppler US were reviewed retrospectively. Among them, 49 patients (mean age, 68.2 ± 7.8 years) confirmed by digital subtraction angiography (DSA) were included. According to the status of diastolic flow, the CRF was divided into continuous CRF (CCRF, n = 27) and intermittent CRF (ICRF, n = 22). The correlation of subtypes of CRF waveform and VA parameters with the severity of SA stenosis was evaluated. The severity of SA stenosis was determined by DSA.

RESULTS

Of those 49 patients, SA occlusion was observed in 33 patients (67%, occlusion group) and severe stenosis in 16 patients (33%, stenosis group). The subtypes of CRF waveforms showed a significant between-group difference (p = 0.005). CCRF exhibited an accuracy of 85.2% (23/27) in diagnosing SA occlusion. The diameter of the target VA with ICRF showed a significant between-group difference (p = 0.041). The target VA diameter ≥ 3.8 mm in ICRF achieved an accuracy of 81.8% (18/22), and its combination with CCRF achieved an accuracy of 83.7% (41/49) in the differentiation of SA occlusion from severe stenosis.

CONCLUSIONS

Subtypes of CRF in VA can help to differentiate SA occlusion from severe stenosis. CCRF has higher accuracy in diagnosing SA occlusion. The CCRF waveform plus VA diameter in ICRF is more accurate for differentiating SA occlusion from severe stenosis.

The segmentation of the vertebral artery: An ambiguous anatomical concept

The course of the vertebral artery from its subclavian artery origin up to its termination at the vertebrobasilar junction is divided into four segments (V1-V4). This segmentation, based on schemes that have evolved since the late nineteenth century, should be a consistent and reproducible anatomical concept. However, the current literature offers conflicting definitions of that scheme, not infrequently within a single article or monograph. The principal inconsistency found in modern publications concerns the termination of the V2 segment, which is either set at the C2 or C1 transverse foramen depending on the scheme considered. Consequently, the portion of the vertebral artery extending between C2 and C1-a frequent site of pathological involvement-either belongs to the V2 or V3 segment. This discrepancy can affect the validity of studies evaluating the diagnosis and management of vertebral artery disorders. A V3 segment extending from the transverse foramen of C2 to the posterior atlanto-occipital membrane and subdivided into vertical, horizontal, and oblique subsegments-a pattern suggested by Barbieri in 1867 and adopted in some modern publications-would provide a simple, precise, and reliable solution without significantly altering the widely accepted division of the vertebral artery into four segments (V1-V4).

Orthostatic hemodynamics in the vertebral artery and blood pressure in patients with orthostatic dizziness/vertigo

OBJECTIVES

Orthostatic dizziness/vertigo (ODV) is a common symptom and is believed to occur due to the cerebral hypoperfusion caused by orthostatic hypotension (OH). However, the detailed mechanism underlying ODV onset is poorly understood. The vertebral artery (VA) mainly supplies blood to the central vestibular system; therefore, the orthostatic decrease of VA blood flow could possibly lead to ODV. This study investigated the orthostatic blood pressure and VA hemodynamics in ODV patients to elucidate the hemodynamic mechanism underlying ODV onset. Furthermore, the influence of orthostatic hypotension (OH) on VA hemodynamics was examined because OH is probably the most common cause of ODV.

METHODS

This study included 181 patients with ODV and 73 control patients without ODV. All subjects underwent an active standing test to measure the extracranial Doppler (ECD) sonography spectrum of the VA and blood pressure (BP). VA blood flow velocity and BP were simultaneously measured for each patient in the supine static position and then in the upright standing positions following 3 min of standing. We investigated the orthostatic change in the average of flow velocity in bilateral VAs (VAFV) and BP for ODV patients compared with the control patients.

RESULT

VAFV in ODV patients was significantly reduced when standing up compared with the control patients. In the ODV patients, there was no difference in orthostatic decrease in VAFV between patients those with OH and without OH. However, the VAFV in the standing position was significantly lower in patients with OH than without OH. In cases with OH, the ODV patients exhibited a greater decrease in VAFV compared with the control patients, but this was not statistically significant. In the absence of OH, a significantly greater orthostatic decrease in VAFV was observed in ODV patients compared with the controls.

CONCLUSION

Our findings suggest that the orthostatic decrease of VA blood flow is deeply involved in the hemodynamic mechanism underlying ODV onset and is possibly associated with OH and other etiologies.

Vertebral artery hypoplasia as an independent risk factor of posterior circulation atherosclerosis and ischemic stroke

ABSTRACT

Vertebral artery hypoplasia (VAH) is a frequent anatomical variation of vertebral arteries, with emerging evidence suggesting that it contributes to posterior circulation ischemia. However, the relationship between VAH and ischemic stroke remains unknown. Hence, this study aimed to determine the prevalence of VAH in patients diagnosed with acute ischemic stroke who were followed up in a neurology clinic and to determine if it can potentially be a risk factor for atherosclerotic stenosis in vertebrobasilar circulation.This retrospective study included 609 patients diagnosed with acute ischemic stroke between January 1, 2019 and January 1, 2020. Demographic of patients, risk factors, radiological and clinical characteristics were evaluated.Posterior circulation was very common in patients with VAH, and the most common locations of atherosclerotic stenosis were V1 and V4 segments of the vertebral artery and the middle segment of basilar artery. Analysis of the risk factors for atherosclerotic stenosis in patients with posterior circulation acute ischemic stroke suggested that VAH was an independent risk factor.Findings of the study suggest that VAH pre-disposes atherosclerotic stenosis in vertebrobasilar circulation, although its mechanism remains unknown. Hemodynamic parameters associated with atherosclerosis could not be measured in vivo. Thus, to better understand the underlying mechanism, conducting studies that examine blood flow parameters with high-resolution magnetic resonance angiography in patients diagnosed with acute cerebral ischemia patients with VAH is warranted.

Ultrasound Assessment of Extracranial Carotids and Vertebral Arteries in Acute Cerebral Ischemia

Assessing ischemic etiology and mechanism during the acute phase of an ischemic stroke is crucial in order to tailor and monitor appropriate treatment and determine prognosis. Cervical Duplex Ultrasound (CDU) has evolved since many years as an excellent screening tool for the evaluation of extracranial vasculature. CDU has the advantages of a low cost, easily applicable, bed side examination with high temporal and spatial resolution and without exposing the patients to any significant complications. It represents an easily repeatable test that can be performed in the emergency room as a first-line examination of cervical artery pathology. CDU provides well validated estimates of the type of the atherosclerotic plaque, the degree of stenosis, as well as structural and hemodynamic information directly about extracranial vessels (e.g., subclavian steal syndrome) and indirectly about intracranial circulation. CDU may also aid the diagnosis of non-atherosclerotic lesions of vessel walls including dissections, arteritis, carotid-jugular fistulas and fibromuscular dysplasias. The present narrative review outlines all potential applications of CDU in acute stroke management and also highlights its potential therapeutic implications.

A preliminary study on colour Doppler ultrasound for the evaluation of intervertebral stenosis of the vertebral artery

AIM

To determine the optimal thresholds for assessing intervertebral segment stenosis through haemodynamic parameters of colour Doppler ultrasound compared with computed tomography (CT) angiography.

MATERIALS AND METHODS

Fifty-four patients diagnosed with intervertebral stenosis on colour Doppler imaging were included. Twenty patients with normal vertebral arteries constituted a control group. Peak systolic velocity at the intervertebral stenosis (PSV_IV-S) and the intervertebral segment distal to the stenosis (PSV_IV-D), end diastolic velocity at the intervertebral stenosis (EDV_IV-S), and the intervertebral segment distal to the stenosis (EDV_IV-D) were measured, and the ratios of PSV_IV-S/PSV_IV-D and EDV_IV-S/EDV_IV-D were calculated. Cut-off values for the diagnosis of <50%, 50-69%, and 70-99% stenosis were determined using a receiver operating characteristics curve.

RESULTS

The optimal cut-off values of haemodynamic parameters for evaluating the intervertebral artery for <50% stenosis were PSV_IV-S ≥81.5 cm/s, EDV_IV-S ≥24.5 cm/s, PSV_IV-S/PSV_IV-D ≥1.49, and EDV_IV-S/EDV_IV-D ≥1.28; for 50-69% stenosis were PSV_IV-S ≥137.5 cm/s, EDV_IV-S ≥36.5 cm/s, PSV_IV-S/PSV_IV-D ≥3.14, and EDV_IV-S/EDV_IV-D ≥2.75; and for 70-99% stenosis were PSV_IV-S ≥216 cm/s, EDV_IV-S ≥55 cm/s, PSV_IV-S/PSV_IV-D ≥4.31, and EDV_IV-S/EDV_IV-D ≥4.16. PSV_IV-S/PSV_IV-D was the most superior haemodynamic parameter, with areas under the curve of 1.000, 0.906, and 0.968 for the diagnosis of <50%, 50-69%, and 70-99% stenosis, respectively.

CONCLUSION

Colour Doppler sonography reliably identifies intervertebral stenosis. The results can be used as a preliminary reference for evaluating intervertebral stenosis.

Cerebral Artery Hypoplasia in a Select Adult Kenyan Population

Background  Hypoplasia of cerebral arteries predisposes to stroke and cerebral aneurysms which have an increased incidence in sub-Saharan Africa. The frequency and pattern of cerebral artery hypoplasia, however, shows population variations, and data from the African population remain scanty. Objectives  This study aimed to determine the percentage of hypoplasia in the anterior, middle, and posterior cerebral, anterior and posterior communicating, basilar, and vertebral arteries. Materials and Methods  Sections of the basilar, vertebral, posterior, and anterior communicating arteries and anterior, middle, and posterior cerebral arteries were taken, processed for histology, and examined with a light microscope at ×40. The images of the vessels were taken by a photomicroscope and circumference analyzed with the aid of Scion image analyzer. The average diameter of 10 sections was taken to be the diameter of the artery in analysis. Hypoplasia was then defined as internal diameter ≤1 mm. Photographs of representative samples of asymmetry were taken, data were analyzed using SPSS, and gender differences were analyzed using the Student's test. Results were presented in tables. Results  Two hundred and eighteen formalin-fixed brains of adult Kenyans at the Department of Human Anatomy, University of Nairobi, were studied. Of the 218, 48 brains (22%) did not have vessels with any form of hypoplasia while 170 (78%) did have vessels. Of these, anterior circulation hypoplasia (anterior cerebral artery and posterior communicating artery) was seen in 100 brains (46%) and posterior circulation hypoplasia (middle and posterior cerebral, basilar, and vertebral arteries) in 69 brains (32%). Conclusion  Cerebral arterial hypoplasia is frequent in the select adult Kenyan population.

Focus on echovascular imaging assessment of arterial disease: complement to the ESC guidelines (PARTIM 1) in collaboration with the Working Group on Aorta and Peripheral Vascular Diseases

The main goal of the present document is to provide a set of practical recommendations for ultrasound imagers who are interested in artery diseases or for physicians who intend to undertake vascular procedures. This is the first part of the work. It is dedicated to general principles of ultrasonography, cervicoencephalic, subclavian, aortoiliac and lower extremity arteries, abdominal aorta, and popliteal aneurysms. It also discusses miscellaneous items such as medial arterial calcinosis, arterial embolism, arteritis, arterial stents and bypasses, false aneurysms, aortic dissection, popliteal entrapment syndrome, and iliac endofibrosis.

Bisystolic Vertebral Artery: Critical Finding or can be Ignored?

The carotid Doppler imaging findings in three adults presenting with vertigo, transient speech difficulty and for cardiac prebypass graft surgery revealing two systolic peaks in one of the vertebral arteries. In presteal situations, vertebral artery waveform shows two systolic peaks with sharp first and rounded second systolic peak or two systolic peaks with a deep cleft between the two peaks with antegrade flow. With increase in stenosis to more than 80% there is bidirectional flow and later flow reversal. We discuss the types of presteal vertebral artery waveforms, its clinical implications and brief review of literature.

The application of a pre-positioned upper cervical traction mobilization to patients with painful active cervical rotation impairment: A case series

BACKGROUND

Cervical mobilization and manipulation have been shown to improve cervical range of motion and pain. Cervical rotatory thrust manipulation has been associated with adverse patient reaction and damage to the V3 segment of the vertebral artery (VA).

OBJECTIVE

To document and describe the effects of an upper cervical (UC) traction based mobilization on participants with restricted and painful cervical rotation and to document if the mobilization changed blood flow velocity through the vertebral artery.

METHODS

This case series examined the effects of a traction based spinal mobilization on two different groups of participants. Group I included 93 participants with restricted bilateral cervical rotation that was also painful at end range. Group II included 30 different participants whose VA blood flow velocity was examined during the same mobilization. Pre- and post-mobilization active cervical rotation, pain intensity levels, and VA blood flow velocity during mobilization was documented.

RESULTS

Paired T-tests were used to determine statistical significance for changes in cervical rotation, and VA blood flow velocity during mobilization. Ninety-three participants in group I demonstrated an average increase of 16 degrees of cervical rotation. No participant demonstrated an increase in pain, and no participant in group II (N= 30) demonstrated a change in VA blood flow velocity.

CONCLUSIONS

The application this UC traction based mobilization improved active cervical rotation, end range rotation pain response, did not cause pain during its application and did not alter blood flow through the VA during application.

Misinterpretation of ischaemic infarct location in relationship to the cerebrovascular territories

PURPOSE

Cerebral perfusion territories are known to vary widely among individuals. This may lead to misinterpretation of the symptomatic artery in patients with ischaemic stroke to a wrong assumption of the underlying aetiology being thromboembolic or hypoperfusion. The aim of the present study was to investigate such potential misinterpretation with territorial arterial spin labelling (T-ASL) by correlating infarct location with imaging of the perfusion territory of the carotid arteries or basilar artery.

MATERIALS AND METHODS

223 patients with subacute stroke underwent MRI including structural imaging scans to determine infarct location, time-of-flight MR angiography (MRA) to determine the morphology of the circle of Willis and T-ASL to identify the perfusion territories of the internal carotid arteries, and basilar artery. Infarct location and the perfusion territory of its feeding artery were classified with standard MRI and MRA according to a perfusion atlas, and were compared to the classification made according to T-ASL.

RESULTS

A total of 149 infarctions were detected in 87 of 223 patients. 15 out of 149 (10%) infarcts were erroneously attributed to a single perfusion territory; these infarcts were partly located in the originally determined perfusion territory but proved to be localised in the border zone with the adjacent perfusion territory instead. 12 out of 149 (8%) infarcts were misclassified with standard assessments and were not located in the original perfusion territory.

CONCLUSIONS

T-ASL with territorial perfusion imaging may provide important additional information for classifying the symptomatic brain-feeding artery when compared to expert evaluation with MRI and MRA.

Pulse Blood Pressure Correlates with Late Outcome in Acute Ischemic Stroke without Significant Culprit Artery Stenosis

BACKGROUND

This study was conducted to test the hypothesis that elevated blood pressure at the early stage is associated with unfavorable outcome in acute ischemic stroke patients with stenosis of less than 50% of the culprit artery.

METHODS

Patients with acute ischemic stroke onset within 48 hours and stenosis of less than 50% of the culprit artery from a prospective stroke registry were analyzed. A modified Rankin Scale score of 1 or lower at 3 months was defined as a favorable late outcome. Univariate and multivariate logistic regression analyses were used to analyze the association between hemodynamic parameters and outcome.

RESULTS

One hundred thirty-six patients fulfilled the selection criteria. Patients with favorable outcome had lower pulse pressure at emergency department (ED) triage, lower systolic blood pressure (SBP) at 24 hours, lower pulse pressure at 24 hours, and lower heart rate (HR) at 24 hours. The univariate logistic regression analysis showed that history of stroke, elevated SBP at 24 hours, elevated HR at 24 hours, elevated pulse pressure at 24 hours, and higher National Institutes of Health Stroke Scale score at ED triage were associated with a less favorable late outcome. Two separate models of multivariate logistic regression analyses showed that pulse pressure at ED triage and pulse pressure at 24 hours, respectively, were significantly associated with less favorable outcome.

CONCLUSIONS

Elevated pulse pressure at the early stage is independently associated with unfavorable late outcome in acute ischemic stroke patients with culprit artery stenosis less than 50%.

Diagnostic Performance of Combined Contrast-Enhanced Magnetic Resonance Angiography and Phase-Contrast Magnetic Resonance Imaging in Suspected Subclavian Steal Syndrome

PURPOSE

The study sought to evaluate the efficacy of magnetic resonance imaging (MRI) in patients with suspected subclavian steal syndrome (SSS) using both contrast-enhanced (CE) MR angiography and phase-contrast (PC) MRI.

METHODS

Fifteen suspected SSSs from 13 patients were evaluated using CE-MR angiography and PC-MRI. Ten patients also received dynamic CE-MR angiography.

RESULTS

All MRI examinations were technically successful. By combining CE-MR angiography with PC-MRI, 10 SSSs were diagnosed in 9 patients. The delay enhancement dynamic technique predicted SSS with a sensitivity, specificity, and accuracy of 57.1%, 100%, and 72.7%, respectively. Without the dynamic technique, affected delay-enhanced arteries were poorly visualized and could be mistaken for occluded vessels. Retrograde vertebral flow by PC-MRI was used to predict ipsilateral SSS with a sensitivity, specificity, and accuracy of 100%, 60%, and 86.7%, respectively. There were 2 false positives including 1 patient with a proximal total occlusion of the affected vertebral artery and another with brachiocephalic steal syndrome rather than SSS. This suggested that retrograde vertebral flow does not always indicate SSS.

CONCLUSIONS

CE-MR angiography combined with PC-MRI is efficacious when evaluating SSS in clinical practice.

Beyond the Bifurcation: There Is More to Cerebrovascular Ultrasound Than Internal Carotid Artery Stenosis!

Carotid ultrasonography (US) is most commonly performed to identify potential areas of flow-limiting stenosis in the internal carotid artery. Identification of stenosis and unstable plaque is important because these entities are leading predictors of stroke, the fourth most common cause of death in the United States. However, US can detect other important but less common vascular pathologies if proper techniques and nuances of these entities are understood.In this article, we discuss the US appearance of abnormalities involving the carotid, vertebral, subclavian, and innominate arteries as well as the key clinical components of each diagnosis. These include congenital variants, dissection, stenosis, and vasculopathy. In addition, correlation of US findings with both magnetic resonance imaging and computed tomography more comprehensively demonstrates the complementary nature of these imaging modalities.

Waveform patterns and peak reversed velocity in vertebral arteries predict severe subclavian artery stenosis and occlusion

This study investigated the value of analyzing spectral Doppler waveform patterns and measuring the peak reversed velocity (PRV) of the vertebral artery (VA) in predicting proximal severe subclavian artery (SA) stenosis and occlusion. Fifty-one patients with proximal SA stenosis were studied retrospectively. Based on the depth of the mid-systolic notch, the Doppler waveforms of the ipsilateral VA were divided into five subtypes (type I, n = 8; type II, n = 8; type III, n = 6; type IV, n = 13; and type V, n = 16). PRV was also measured. PRV receiver operating characteristic curves were constructed to obtain the best cutoff value for predicting severe SA stenosis or complete SA occlusion. The results indicated that both VA Doppler waveform and PRV were associated with the degree of SA stenosis (p < 0.05). PRV and the Doppler waveform in the VA had similar accuracy in predicting SA occlusion (84.3%, 43/51). PRV was more accurate than VA waveforms in predicting severe SA stenosis (98%, 50/51 vs. 94.1%, 48/51). However, no significant differences between the two methods in predicting severe SA stenosis were observed (p = 0.84). Thus, with severe obstruction of the SA, typical Doppler waveform patterns of the VA could be observed. PRV is a helpful criterion in predicting severe stenosis and occlusion of the SA.

Vertebral Artery Hypoplasia in a Black Kenyan Population

This study examined the characteristics of vertebral artery hypoplasia in 346 arteries of adult black Kenyans. The circumference was measured on haematoxylin/eosin stained microscopic sections of the distal one-third of the intracranial vertebral arteries using scion image analyser. Internal diameter was calculated in millimetre. Data were analysed using SPSS version 16.0. Vertebral artery hypoplasia (diameter < 2.0 mm) occurred in 100 (28.9%) arteries. Sixty of these (17.3%) were on the left and 40 (11.6%) on the right. Sixty (17.3%) were in females while 40 (11.6%) were in males. The side and gender differences were statistically significant at confidence interval of 95%. Frequency of vertebral artery hypoplasia was higher than in most other populations studied. The condition differs from that in other populations because it is more common on the left side and in females. We recommend ultrasound, angio-CT, or angio-MRI evaluation of vertebral arterial system before diagnostic or interventional procedures on posterior circulation.

Completely reversed flow in the vertebral artery does not always indicate subclavian steal phenomenon

We evaluated the causes, differential diagnosis and clinical significance of completely reversed flow (CRF) in the vertebral artery (VA). Twenty-three patients diagnosed with CRF in the VA by Doppler ultrasound were studied retrospectively. CRF was divided into intermittent CRF and continuous CRF. The peak reversed velocity (PRV) and ratio of time in intermittent CRF to one cardiac cycle (tICRF/CC) were calculated. Causes of CRF were determined on the basis of previous angiography results. The results indicated that subclavian steal phenomenon (SSP) caused all cases of continuous CRF (n = 8). Intermittent CRF was caused by SSP (n = 6) or proximal VA occlusion (n = 9). PRV and tICRF/CC were increased in SSP as compared with VA occlusion (p < 0.05). Using a cutoff of tICRF/CC = 0.30, we achieved excellent accuracy in predicting the cause of intermittent CRF (100%) and posterior circulatory infarction (91%). Thus, analysis of CRF patterns and measurements of VA parameters can be used in differential diagnosis of the causes of CRF and in prediction of posterior circulatory infarction.

Probabilistic mapping of the cervical sympathetic trunk ganglia

The goal of this study was to create a heat map indicating the probabilistic location of major ganglia of the cervical sympathetic trunk (CST). Detailed dissections of human cadaveric specimens, followed by spatial registration and analysis of the cervical sympathetic ganglia in the neck and upper thorax regions (C1-T1) were performed in 104 neck specimens (both sides from 52 cadavers). Unbiased parametric mapping, visualized with a heat map, revealed a general pattern of two major ganglia located on both sides of the neck: The superior cervical ganglion (SCG) was located 80-90 mm superior to the point at which the vertebral artery entered the transverse foramen (VA-TF); the stellate ganglion (SG) was located approximately 10 mm inferior to the VA-TF in 80% of our sample, or surrounding the VA-TF in the remaining 20% of our sample. In between these ganglia, a highly variable number of smaller and less prevalent ganglia were present on either side of the neck. The middle ganglia on the right side of the neck were located closer to the SCG, possibly indicative of the middle cervical ganglion. On the left side the middle ganglia were located closer to the SG, perhaps indicative of the vertebral ganglion or the inferior cervical ganglion. Individual specimens could be classified into one of seven different patterns of cervical trunks. The results may help surgeons and anesthesiologists more accurately target and preserve these structures during medical procedures.

Vascular pathology in the extracranial vertebral arteries in patients with acute ischemic stroke

Introduction

Vascular pathology in the extracranial vertebral arteries remains among the possible causes in cryptogenic stroke. However, the diagnosis is challenged by the great variety in the anatomy of the vertebral arteries, clinical symptoms and difficulties in the radiological assessments. The aim of this study was to assess the prevalence of CT angiography (CTA)-detected pathological findings in the extracranial vertebral arteries in an acute stroke population and secondly to determine the frequency of posterior pathology as probable cause in patients with otherwise cryptogenic stroke.

Method

The analysis was based on 657 consecutive patients with symptoms of acute stroke and a final diagnosis of ischemic stroke or transient ischemic attack. On admission, a noncontrast CT cerebrum and CTA were performed. A senior consultant neuroradiologist, blinded to clinical data, reviewed all CTA scans systematically, assessing the four segments of the extracranial vertebral arteries. First, the frequency of pathological findings including stenosis, plaques, dissection, kinked artery and coiling was assessed. Subsequently, we explored the extent of the pathological findings that were the most plausible causes of stroke, namely either a possible dissection or a kinked artery.

Results

Findings in the extracranial vertebral arteries included significant stenosis (0.8%), atherosclerotic plaque types (3.8%), possible dissections (2.6%), kinked arteries (2.6%) and coiling (32.0%). Eighteen patients (2.8%) with pathological findings had an unknown cause of stroke, likely posterior symptoms and no clinical stroke symptoms from the anterior circuit. Of these, 3 cases were kinked arteries (0.5%) and 15 cases (2.3%) were possible dissections.

Conclusion

We found that in approximately 3% of the study population, the most plausible cause of the cryptogenic strokes was due to a pathological finding in the posterior extracranial vertebral arteries, being either a possible dissection or a kinked artery. In general, posterior vascular pathology is not uncommon, and CTA is a useful modality in the detection of changes based on characteristics and locations of findings in the extracranial vertebral arteries. Ultrasound examination can be a useful supplementary tool in deciding the consequence of vascular findings on CTA.

Bidirectional flow in the vertebral artery is not always indicative of the subclavian steal phenomenon

OBJECTIVE

To evaluate the causes of bidirectional flow in the vertebral artery detected by Doppler sonography and its differential diagnosis.

METHODS

Twenty-nine patients with bidirectional flow in the vertebral artery were retrospectively studied. The vertebral artery parameters, including peak antegrade velocity (PAV), peak reversed velocity (PRV), maximum peak velocity (MPV), peak systolic velocity, resistive index (RI), and diameter, were measured. The MPV was defined as the MPV of bidirectional flow regardless of the velocity of antegrade or retrograde flow. To better predict the cause of bidirectional flow, receiver operating characteristic curves were constructed for these parameters, and the best cutoff values were obtained. The cause of bidirectional flow was determined by angiography.

RESULTS

The causes of bidirectional flow were classified as the subclavian steal phenomenon (n = 21) and factors unrelated to the steal phenomenon (n = 8, including a hypoplastic vertebral artery [n = 4] and proximal vertebral artery stenosis and occlusion [n = 4]). Significant differences were observed between the steal phenomenon and non-steal phenomenon groups (P< .05) for MPV, PRV, PAV, target vertebral artery diameter, and contralateral RI. To determine the cause of bidirectional flow, areas under the receiver operating characteristic curves for the different parameters were obtained: 0.929 for MPV, 0.881 for PRV, 0.824 for PAV, 0.753 for target vertebral artery diameter, and 0.845 for contralateral RI. The cutoff value for MPV was 26.1 cm/s, and the accuracy was 93% (27 of 29).

CONCLUSIONS

Bidirectional flow in the vertebral artery is not always indicative of the subclavian steal phenomenon. Measurement of hemodynamic parameters in the vertebral artery, such as MPV, can facilitate determination of the cause of bidirectional flow.

HEMODYNAMIC ANALYSIS OF STENT EXPANSION RATIO FOR VERTEBRAL ARTERY OSTIAL STENOSIS INTERVENTION

Stents have been used successfully for treating stenosis in the vertebral artery ostium. The size of stent is found to be an important link in stent design, implantation strategy, and clinical outcome. However, there is no direct evidence of a relationship between stent expansion ratio and the stented artery. This study investigated the influence of stent expansion ratio on local hemodynamics (such as pressure distribution and pressure gradient) of vertebral artery ostial stenosis to determine a possible biomechanical mechanism. Computer-aided design of models with stents with different expansion ratios (i.e., 1.00, 1.125, and 1.25) and internal flow fields were created. All the models were meshed and simulated using computational fluid dynamics (CFD) tools. The comparisons of pressure distribution and pressure gradient are specifically presented. The results showed that the pressures increase and the pressure gradient decreases after stent implantation. The mean pressure at the stented region rises significantly with the increase of stent oversize. The heterogeneity of the pressure gradient was reduced at the stented region in the case with the expansion ratio of 1.125, whereas this effect was not obvious in other expansion ratio cases. Additionally, the combination of higher pressure and a lower pressure gradient in the case with the expansion ratio of 1.125 was significantly observed. This study demonstrated that the proper size of stent, especially with regards to the expansion ratio, is an important factor influencing the treatment of vertebral artery ostial stenosis. It is the recognition of the necessity to consider the relationship between expansion ratio and stenosis in vertebral artery ostium. These findings could help to address the optimization of hemodynamic performance for stent implantation.

Ultrasound analysis of the vertebral artery during non-thrust cervical translatoric spinal manipulation

OBJECTIVE

Cervical translatoric spinal manipulation (TSM) techniques have been suggested as a safer alternative to cervical thrust rotatory techniques. The objective of this study was to determine the effect of three C5-C6 non-thrust TSM techniques on vertebral artery (VA) lumen diameter (LD) and two blood flow velocity parameters. The two-tailed research hypothesis was that the TSM techniques would result in a significant change (increase or decrease) in blood flow velocity and arterial LD at the C5-C6 intertransverse portion of the VA.

METHODS

In a sample of 30 subjects representative of a clinical population, color-coded duplex Doppler diagnostic ultrasound imaging was used to collect data on LD, peak systolic velocity (PSV), and end diastolic velocity with the cervical spine positioned in neutral and in three different manipulation positions. Pair-wise mean differences between measurements at baseline (neutral position) and in all three manipulation positions were analyzed using two-tailed paired t-tests with alpha set at 0·05.

RESULTS

Of the 18 paired comparisons, there were four statistically significant differences between measurements in the neutral position and a manipulation position, three concerning LD and one PSV.

DISCUSSION

The three significant differences in LD ranged from 4·6 to 3·2% and were not associated with changes in blood flow velocity. The one significant change in PSV was only 6·6 cm/s. A value that still greatly exceeded the end diastolic velocity. No subject experienced symptoms associated with VA compromise. This study has provided evidence for the safety of the three lower cervical non-thrust TSM techniques on the current population studied. Further study is required on thrust versus non-thrust TSM techniques and on levels other than C5-C6.

Ultrasonic analysis of the anatomical relationships between vertebral arteries and internal jugular veins in children

BACKGROUND

Accidental puncture of the vertebral arteries (VAs) can occur through the internal jugular veins (IJVs) during central venous catheterization (CVC). We evaluated the anatomic relation of the VAs to the IJVs in children undergoing IJV cannulation.

METHODS

Fifty-five patients were placed in the supine position under general anesthesia. The right IJV, common carotid artery (CCA), and VA were described with an ultrasound probe perpendicular to all planes of the skin at the mid-portion between the suprasternal notch and mastoid process. The depth from the skin to VAs (D), width of the VAs (W), and distance from the IJVs to VAs (DIV) were measured. The extent of overlap between the IJVs and VAs was classified into overlapping, partially overlapping, and nonoverlapping. The risk was scored as 0-3 for each measurement. The scores were added and categorized into a low-risk group (L), 0-3, moderate-risk (M) group, 4-7; and high-risk (H) group, 8-10.

RESULTS

Mean (sd) age was 20.3 (33.9) months, height was 72.1 (26.0) cm, and weight was 8.9 (9.0) kg. The mean D, W, and DIV were 15.1 (3.3), 2.8 (1.1), and 4.6 (1.8) mm, respectively. Of the 55 patients, 7 were in group H, 33 in group M, and 15 in group L.

CONCLUSIONS

Seven of the 55 children were categorized under the H group for accidental puncture of the VAs. Thus, it is important to identify the presence of the VAs to avoid accidental puncture during pediatric CVC.

Diagnosis and percutaneous treatment of partial subclavian steal: Doppler ultrasonography and phase contrast magnetic resonance angiography findings and a brief review of the literature

A 66-year-old woman presented with back pain and arm claudication. Severe stenosis of the left proximal subclavian artery was detected incidentally by thorax computed tomography. Doppler ultrasonography and phase contrast magnetic resonance angiography (PCMRA) evaluation revealed partial subclavian steal. The stenosis was successfully treated with percutaneous stenting. Imaging findings are described and a brief review of the literature emphasizing the role of PCMRA in diagnosing partial steal is discussed.

Extracranial and intracranial sonographic findings in vertebral artery diseases

OBJECTIVE

The aim of this review is to illustrate the sonographic features that can be detected in vertebral artery (VA) diseases.

METHODS

We conducted a review of sonographic findings in VA diseases.

RESULTS

Various VA diseases are described, and sonographic techniques and features are discussed.

CONCLUSIONS

Posterior circulation vascular imaging can be performed by means of various neuroimaging techniques. Intra-arterial angiography remains the reference standard. The use of this technique has become even more widespread since it has become possible to perform endovascular procedures; it is, however, an invasive procedure that is associated with a not irrelevant level of risk. Computed tomographic angiography and magnetic resonance angiography with and without contrast agents have been proposed as less invasive alternatives, although these techniques can only be performed in the radiology unit and may not be readily available in daily clinical management. Sonography, which combines an extracranial and intracranial evaluation, is highly suited to the assessment of the vertebrobasilar system on account of its widespread availability and its unique capacity to study real-time hemodynamics. Furthermore, new sonographic applications and sonographic contrast agents have improved the sensitivity and specificity of this technique with regard to diagnostic accuracy for the posterior circulation.

Computer simulation of vertebral artery occlusion in endovascular procedures

OBJECTIVE

The aim of this work is to establish a computational pipeline for the simulation of blood flow in vasculatures and apply this pipeline to endovascular interventional scenarios, e.g. angioplasty in vertebral arteries.

METHODS

A patient-specific supra-aortal vasculature is digitized from a 3D CT angiography image. By coupling a reduced formulation of the governing Navier-Stokes equations with a wall constitutive equation we are able to solve the transient flow in elastic vessels. By further incorporating a bifurcation model the blood flow across vascular branches can be evaluated, thus flow in a large vasculature can be modeled. Vascular diseases are simulated by modifying the arterial tree configurations, e.g. the effective diameters, schematic connectivity, etc. Occlusion in an artery is simulated by removing that artery from the arterial tree.

RESULTS

It takes about 2 min per cardiac cycle to compute blood flow in an arterial tree consisting of 38 vessels and 18 bifurcations on a laptop PC. The simulation results show that blood supply in the posterior region is compensated from the contralateral vertebral artery and the anterior cerebral arteries if one of the vertebral arteries is occluded.

CONCLUSION

The computational pipeline is computationally efficient and can capture main flow patterns at any point in the arterial tree. With further improvement it can serve as a powerful tool for the haemodynamic analysis in patient-specific vascular structures.

Sonographic diagnosis of congenital variations of the extracranial vertebral artery and assessment of its circulation

OBJECTIVE

The purpose of this study was to assess the value of sonographic examination of congenital variations of the extracranial vertebral artery associated with posterior circulation ischemia in children.

METHODS

Sonography was performed on the vertebral arteries of 82 patients aged 2.5 to 14 years with a history of headache, vertigo, and syncope. An additional 86 unaffected children aged 2 to 14 years were included as a control group. Indices such as the diameter, passage, and morphologic characteristics of the vertebral artery were measured, as well as the arterial volume. The median values of these parameters were used for comparisons.

RESULTS

A comparison between the control and 5 case groups showed that the bilateral diameter and volume in these 6 groups had significant variations (P < .05). A narrow diameter and abnormal passage of the vertebral artery resulted in reduced blood flow and an inadequate blood supply in the posterior circulation. There were 42 cases found to have congenital variations of the extracranial vertebral artery, 12 cases of congenital asymmetry, 15 cases of tortuosity, 5 cases of bilateral congenital asymmetry with tortuosity, 6 cases of congenital hypoplasticity, and 4 cases of an abnormal path.

CONCLUSIONS

Certain children with a history of recurrent signs of vertigo, headache, and syncope were found to be afflicted with congenital variations of the extracranial vertebral artery. Sonography not only revealed the morphologic variations of the extracranial vertebral artery but also allowed an assessment of changes in blood flow such that posterior circulation ischemia could be determined.

Atypical suboccipital vertebral artery blood flow in healthy subjects: case studies using real-time ultrasound

Manual therapists and other professionals are using real-time ultrasound increasingly to visualize vessels and determine their diameter and blood flow. Four case studies are presented to show atypical ultrasound profiles of the suboccipital vertebral artery (VA3) in healthy, young individuals. VA3 diameters and blood flow velocities were measured with the subjects sitting, and the cervical spine in the neutral position then with active, full-range rotation to the left and right. None of the subjects reported any signs or symptoms of vertebrobasilar ischemia (VBI) during the measurement procedure, despite an absence of typical VA3 ultrasound profiles on one side in two of the individuals and a decreased unilateral VA3 blood flow in the other two subjects. Possible reasons for the atypical findings are proposed. Anatomical variations of VA3 and conditions such as obesity may give rise to atypical real-time ultrasound measurements of VA3 blood flow, particularly when associated with cervical spine rotation. The possibility of altered VA3 blood flow because of such factors, which may give rise to false-positive or false-negative findings in the standard VBI test, should be considered by manual therapists in pretreatment assessments and treatment programs in professional practice.

CTA in the detection and quantification of vertebral artery pathologies: a correlation with color Doppler sonography

INTRODUCTION

We evaluated the feasibility of multidetector CT angiography (MDCTA) in the examination of vertebral artery (VA) pathologies and correlated the results with those of color Doppler sonography (CDS).

METHODS

In this retrospective cohort analysis, we identified 65 patients with suspected cerebrovascular disease, who underwent MDCTA and CDS of the supraaortic vessels within a maximum period of 1 month. We evaluated the feasibility and image quality of MDCTA in this indication, compared the value of reformatted images and axial source images in the grading of stenoses and correlated these results with those of CDS.

RESULTS

The image quality of the MDCTA examination was classified as good in 64 patients (98.5%) and as moderate in 1 patient (1.5%). Axial source images and reformatted images agreed perfectly in terms of stenosis detection and grading as well as the detection of hypoplastic VAs (kappa = 1). The correlation between MDCTA and CDS was moderate (kappa = 0.56) in terms of stenosis detection and quantification and poor (kappa = 0.35) in terms of detection of hypoplasia of the VA.

CONCLUSION

MDCTA is a feasible method for the evaluation of VA pathologies providing a good image quality. Image reformatting does not add any diagnostic value to the interpretation of axial source images. The correlation between MDCTA and CDS is only moderate, reflecting the clinically important limitations of CDS in this indication.

Transient tetraplegia after cervical facet joint injection for chronic neck pain administered without imaging guidance

We report about a patient in whom transient tetraplegia with intact proprioception occurred immediately after infiltration of a facet joint at the C6 level guided by anatomical landmarks. After positioning the patient supine and applying atropine and oxygen, respiration and circulation were stable and all symptoms resolved within the next 30 min. The type of neurological pattern and the course of disease suggest an inadvertent injection into a cervical radicular artery that reinforces the anterior spinal artery. This complication is potentially serious and may be permanently disabling or life threatening. It should be considered by any clinician performing "blind" zygapophysial joint injections in the cervical spine. Using imaging guidance should help prevent this type of complication.

Follow-up of extracranial vertebral artery stents with Doppler sonography

OBJECTIVE

The objective of our study was to determine the Doppler sonography findings suggestive of restenosis in the follow-up of patients treated by stent placement in the extracranial vertebral artery.

CONCLUSION

Follow-up of vertebral artery stents with Doppler sonography may be performed by direct insonation of the stent or by indirect measurements from the V2 segment (the part of the vertebral artery that courses within the intervertebral foramina). The V2 segment Doppler sonography measurements may guide future examinations and provide essential information regarding the proximally deployed stent.