Vertebral Artery Diameter Research Articles

Association of the RNF213 p.R4810K Variant With the Outer Diameter of Cervical Arteries in Patients With Ischemic Stroke

Background We investigated the impact of the p.R4810K variant of RNF213 (ring finger protein 213) gene, a susceptibility gene of moyamoya disease in East Asia, on the outer diameter of cervical parts of carotid and vertebral arteries (VAs). Methods We examined consecutive Japanese patients with ischemic stroke who underwent carotid ultrasonography between 2015 and 2019. Patient background and the carotid ultrasonography‐measured outer diameter of extracranial cervical arteries, including the common carotid artery, internal carotid artery, external carotid artery, and cervical VA, were compared between variant carriers and noncarriers. Outer diameters of each artery were defined as the mean distance from far to near wall adventitia of right and left target arteries using carotid ultrasonography. The average diameter of both cervical portions of common carotid arteries, internal carotid arteries, external carotid arteries, and the dominant side diameter of both cervical VAs were used. Results Of the 617 adult patients (204 women; median age, 74 years) analyzed, 26 (4.2%) carried the RNF213 p.R4810K variant. Variant carriers were significantly younger ( P <0.01) and had more frequent steno‐occlusion of the M1 segment of the middle cerebral artery ( P <0.01). Multivariate logistic regression analysis showed that variant carriers had significantly smaller mean diameters in the common carotid artery (7.25 versus 8.22 mm; adjusted odds ratio [aOR] per 1 mm decrease, 2.94; 95% CI, 1.69–5.00), cervical internal carotid artery (4.99 versus 5.55 mm; aOR, 1.66; 95% CI, 1.03–2.70), and cervical VA (3.55 versus 4.10 mm; aOR, 2.56; 95% CI, 1.33–4.76) than noncarriers. Mean diameters of the common carotid artery (aOR, 3.44; 95% CI, 2.08–5.88) and cervical internal carotid artery (aOR, 2.04; 95% CI, 1.23–3.33) and the dominant diameter of the cervical VA (aOR, 3.23; 95% CI, 1.72–5.88) were also smaller in variant carriers even when the analysis was restricted to patients without bilateral steno‐occlusion in target vessels or intracranial arteries distal to target vessels. Conclusion RNF213 p.R4810K variant carriers have smaller cervical arterial outer diameters in both anterior and posterior circulations than noncarriers with ischemic stroke. Registration URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02251665.

Reconsidering the Relationship Between Hand Preference and Cerebral Vascular Dominance: A Computed Tomography (CT) Angiography Study.

To date, it has been suggested that there may be many genetic, environmental, and vascular factors that affect hand preference. In previous studies evaluating the relationship between cerebral dominance and hand preference, carotid and vertebral artery (VA) Doppler ultrasonography (USG) was generally preferred; and these studies only measured VA diameters. Unlike other studies, we aimed to reevaluate the relationship between hand preference and cerebral vascular dominance by measuring VA and internal carotid artery (ICA) diameters. In addition, we used carotid and VA computed tomography (CT) angiography instead of Doppler USG. A total of 345 participants were included in the study. The results of carotid and VA CT angiography taken during hospitalization were retrospectively evaluated by two radiologists, and the Edinburgh Hand Preference Questionnaire was applied to these patients. In right-handed patients, the diameter of the left VA was significantly larger than the diameter of the right VA (p = 0.005). In left-handed patients, the diameter of the left ICA was larger than the diameter of the right ICA, but the difference was not statistically significant (p = 0.055). There was no significant difference between the diameter of the right and left ICA in right-handed patients (p = 0.771). In our study, we found a correlation between the dominant hemisphere VA diameter and hand preference. Using CT angiography, we were able to eliminate many challenges of ultrasonography that make radiological evaluation difficult, such as differences of opinion between radiologists, and technical and anatomical reasons.

Low-dose three-dimensional CT angiography for the evaluation of posterolateral protrusion of the vertebral artery over the posterior arch of the atlas: a quantitative anatomical comparison study of the rotational and neutral positions

To investigate the changes in relevant anatomical parameters of posterolateral protrusion of the vertebral artery (VA) between head-neck rotational and neutral positions using low-dose three-dimensional computed tomography angiography (3D-CTA). Low-dose 3D-CTA images obtained for various craniocervical diseases in 36 non-dominant VA side patients with neutral, left and right head-neck rotational positions were evaluated. The relevant parameters from superior and inferior views, including external diameter (ED), internal diameter (ID), transverse diameter (TD), heights and diameters of posterolateral protrusion of the VA over the posterior arch of the atlas in the neutral and rotational positions, were recorded and compared. There was no significant differences in the rotational angle (left/right: 31.23±6.60/29.94±6.09°, p>0.05). There were no significant differences in heights and diameters of bilateral VA between rotational and neutral positions (all p>0.05). The contralateral ID, ED, and TD of the rotational positions were significantly shorter than those of the neutral position (all p<0.05), while there were no significant differences in the three ipsilateral diameters (all p>0.05). Posterolateral protrusion of the VA is not uncommon in the population, and surgeons should be aware of its presence, especially the increased possibility of injury to the VA caused by head-neck rotation, during the operation; thus, preoperative evaluation by low-dose 3D-CTA should be considered.

Morphometric Study of the Intracranial Segment of the Vertebral Artery.

BackgroundThe vertebral artery (VA) forms the caudal part of the circle of Willis and is responsible for one-third of the blood supply of the cerebellum, pons, middle ear, and the upper part of the spinal cord and its meninges. The highest potential risk of injury to VA during cervical pedicle screw implantation is at C3 and then at C6. Knowledge about the morphometry of VA provides a better understanding of clinical conditions such as vertebra basilar insufficiency (VBI). Similarly, the knowledge of variation in the VA is needed during cervical pedicle screw implantation, which possesses the highest potential risk to VA at the C3 level. The origin of the vertebral artery from the aortic arch reached the upper cervical vertebra than the vertebral artery of subclavian origin. The length of the VA is greater on the left side than the right-side artery. Understanding and reporting of the same are essential to creating awareness that can aid in endarterectomy, angioplasty, and radiological procedures. Variations are noted in morphometry between sides.AimTo determine the morphometry of the vertebral artery (VA) with emphasis on the fourth segment (V4) and its variations using computed tomography angiogram (CTA).Materials and methodsThis present retrospective study was conducted in the Departments of Anatomy and Radiology and Imaging Sciences, Saveetha Medical College and Hospital. Participants were patients who took a head and neck CT for various clinical reasons. About 50 CT images, 33 male and 17 females, were selected from the archives. The length, diameter, and entry level of VA were studied. The data were tabulated and statistically analyzed.ResultThe mean length of VA was 24.49 ± 3.02 (cm) on the left side and 24.28 ± 3.91 (cm) on the right side in female subjects and was found to be 22.78 ± 1.7 (cm) on the left side and 21.5 ± 2.7 (cm) on the right side in male subjects. The mean diameter of VA at the level of the foramen magnum was 0.32 ± 0.05 (cm) on the right side and 0.322 ± 0.07 (cm) on the left side in females, 0.3 ± 0.064 (cm) on the left side and 0.26 ± 0.086 (cm) on the right side in males.ConclusionThe length of VA was found to be statistically more on the left side than on the right side. The variations in morphometry seen can aid in various surgical and radiological procedures.

Abstract WMP91: Angiographic Predictors Of Balloon Test Occlusion Outcomes

Introduction: Balloon test occlusion (BTO) with adjunctive single-photon emission computed tomography (SPECT) has been utilized to predict clinical tolerance after permanent internal carotid artery (ICA) occlusion. Cerebrovascular anatomical characteristics might predict BTO outcomes and identify patients susceptible to test failure. Methods: We performed a single center retrospective study of patients who underwent catheter based cerebral angiogram and ICA BTO from July 2013 to June 2020. SPECT imaging was completed in all the patients who passed the clinical BTO; technetium 99m-ethyl cysteinate dimer was injected intravenously after 15-30 min of occlusion and induced hypotension. The diameter of each of the vessels of the Circle of Willis was measured angiographically. The severity of hypoperfusion on SPECT imaging was classified as none, mild, low intermediate, high intermediate, and severe. Results: A total of 57 patients underwent BTO; neoplasia was the most common indication (n=43, 75%). Twelve patients (21.1%) developed neurologic symptoms and clinically failed the BTO; 45 patients (78.9%) passed and proceeded to SPECT. Contralateral dominant vertebral artery (p=0.02), smaller ACom (p=0.002) and ipsilateral PCom (p=0.03) diameters were correlated with clinical BTO failure. Smaller ACom was most predictive with an AUC of 0.907. The Youden index identified an ACom diameter threshold of 1.1 mm, which demonstrated a sensitivity of 91.7% and specificity of 77.8% (OR 0.026, 95% CI 0.003 - 0.226, ROC=0.847) for the prediction of BTO failure. Patients with severe SPECT asymmetry had significantly smaller caliber ACom arteries (ACom median diameter 0.95 mm vs. rest of cohort median 1.4; p=0.0073). Conclusions: BTO outcomes may be predicted using angiographic findings. A small (&lt;1.1 mm) anterior communicating artery, and, less significantly, a small ipsilateral posterior communicating artery can be used to identify patients who are likely to fail BTO.

Validity about Diameter of Guiding Catheter for Posterior Circulation Derived by MRA Study.

The development of large-bore aspiration catheters (ACs) has advanced the treatment of mechanical thrombectomy (MT) and their use requires larger guiding catheters (GCs). However, due to the small vessel diameter of the vertebral artery (VA), it can be difficult to cannulate large-bore GC to the VA. This study aims to determine the percentage of VAs that are amenable to GC placement based on the use of a large-bore AC and to clarify the diameters of VAs in the general population using neck MRA. Left and right VA diameters were measured in 1394 consecutive adult patients who underwent neck MRA at our hospital between April 2020 and June 2021. Sex and left/right differences in the VA diameters, as well as the conformity ratios of GCs (6, 7, and 8 French) to right and left VAs, were examined. The patients ranged in age from 18 to 98 years (mean 70.8 ± 13.5 years), with 770 (55.2%) males. The left and right VA mean diameters were 2.82 ± 0.75 mm (range 0-5.1 mm) and 2.65 ± 0.75 mm (range 0-5.3 mm), respectively. The conformity ratios of 6, 7, and 8 French GC to left and right VAs were 85.3% and 79.9%, 74.9% and 68.4%, and 60.9% and 53.7%, respectively. When performing MT for the posterior circulation system, a large-bore AC of 0.060 inches or larger is usually required, and GC placement of 7-French or larger is necessary. The results of this study showed that 7-French GC placement is achievable in approximately 70% of these cases.

Morphometric Analysis of V2 Segment of Vertebral Artery in Patients with Symptomatic Neck Pain in South Indian Population – A CT Angiography Based Study

Objectives: The morphometric changes in the vertebral artery are essential for various interventions. Inadequate details about it can lead to risk of vertebral artery injury and other complications. This study explains the normal anatomical course of V2 segment of vertebral artery which is more prone for iatrogenic injury.&#x0D; Materials and Method: 25 adult patients with symptomatic neck pain were involved in the study. Various measurements were made from seventh cervical vertebra (C7) to the third cervical vertebra (C3) that included Distance from midline to VA, Distance from medial margin of Longus Colli to VA, Perpendicular distance from anterior margin of transverse process to center of VA, Horizontal distance from anterior tubercle to VA, sagittal and coronal diameter of the transverse foramen and vertebral artery.&#x0D; Result: Distance from midline, Distance from medial margin of Longus Colli, Perpendicular distance from anterior margin of transverse process to center of VA and Horizontal distance from anterior tubercle were increased towards right compared to left side. The sagittal and coronal diameter of the transverse foramen and vertebral artery decreased from C6 to C3 vertebra. Vertebral artery dominance was seen on left side in all cases.&#x0D; Conclusion: Preoperative assessment by computed tomography angiography helps to know the course of the vertebral artery, understand its patterns and assess various abnormalities thereby aids in preventing complications in future surgeries.

Analysis of posterior circulation diameters depending on age, sex and side by computed tomography angiography.

Posterior circulation of brain is important because of vital organs' blood supply provided by them. In this study, we evaluate the relationship of posterior circulation measurements with age, gender and side by using computed tomography angiography (CTA) images. A total 199 brain CTA examinations were retrospectively analysed for all posterior circulation arteries (vertebral artery, basilar artery, posterior cerebral artery [PCA], superior cerebellar artery [SCA], anterior inferior cerebellar artery, and posterior inferior cerebellar artery [PICA]) to compare the difference based on age, gender and side. There is no correlation between age and the mean diameters of all vessels (p > 0.05). The mean diameter of left vertebral artery was higher than right vertebral artery in all genders (p = 0.004 for males and p < 0.001 for females). The mean diameter of left SCA and PICA were higher than right SCA and PICA in females (p = 0.032 and p = 0.027, respectively). The mean diameters of basilar, left PCA, left SCA, left vertebral, right PCA, right SCA, right PICA and right vertebral artery were higher in males and that differences were statistically significant (p < 0.001, p = 0.002, p = 0.006, p = 0.004, p = 0.001, p = 0.003, p = 0.002, and p = 0.006, respectively). The posterior circulation vessel diameter is not affected by aging. The mean diameters of basilar artery, both PCAs, both SCAs, right PICA, both vertebral arteries were higher in males. The mean diameter of left vertebral artery is higher than that of right vertebral artery in all genders.

Associations Between Transcranial Doppler Flow Velocities, Laboratory Parameters, and Clinical Features in Turkish Children With Sickle Cell Disease.

Stroke is one of the major complications of sickle cell disease (SCD). Stroke features either occlusion of, or stenosis at, the origin of one of the large intracerebral arteries, the internal carotid artery (ICA), and/or the middle cerebral artery (MCA). We sought correlations between cerebral blood flow velocities and the laboratory and clinical findings of patients with SCD. Fifty-three pediatric SCD patients (39 with HbSS, 14 with HbSβ0) were analyzed. The mean patient age was 12.9±3.9 years. The control group contained 24 healthy individuals. The time-averaged maximum mean velocity (TAMMV) and resistive index (RI) of the MCA, the TAMMVs of the ICA and vertebral artery (VA), and the diameter of the VA were estimated through transcranial Doppler ultrasonography using a 2.5 MHz transducer, in accordance with the Stroke Prevention Trial in Sickle Cell Anemia (STOP) protocol. We evaluated the relationships between the TAMMVs, laboratory parameters, and clinical findings. The mean±SD MCA TAMMV was 161.2±35.4 cm/s in patients with HbSS and 185.8±62.9 cm/s in patients with HbSβ0. The mean MCA TAMMV, RI, ICA TAMMV, VA TAMMV, and VA diameter were 168.5±43.9 cm/s, 0.63±0.06, 116.8±25.5 cm/s, 69.2±18.5 cm/s, and 3.5±0.61 mm for all SCD patients, respectively. In the control group, the mean MCA TAMMV, RI, ICA TAMMV, VA TAMMV, and VA diameter were 103.8±28.8 cm/s, 0.53±0.04, 96.4±27.8 cm/s, 40.3±12.1 cm/s, and 3.4±0.6 mm, respectively. Although the differences were not significant, TAMMVs were higher in HbSβ0 patients taking hydroxyurea; those with hemoglobin levels <8 g/dL, ferritin levels >1000 ng/dL, mean platelet volume >12 fL, or red cell distribution width >18%; or required chelation, or were below the third percentiles of weight and height. The TAMMV was significantly higher only in SCD patients who complained of headache. High ferritin and low hemoglobin levels, a high mean platelet volume, a high red cell distribution width, low weight (below the third percentile), and a short height (below the third percentile) may be associated with elevated cerebral blood flow velocities and an increased stroke risk in children with SCD. Children with such features should be closely followed-up through transcranial Doppler ultrasonography examination.

The effect of vertebral artery characteristics on cervical discogenic pain and disability

Introduction : Cervical discogenic pain, which is characterized by a stiffness or pain in neck movement, generally occurs as a result of disc degeneration. On the other hand; vascular pathologies of the cervical region, especially vertebrobasilar insufficiency, may give rise to similar findings in patients; it can also be detected simultaneously with cervical disc pathologies. . In this study, it was aimed to investigate whether the circulatory properties of the vertebral arteries have an effect on the neck pain and functional status of the patients.&#x0D; Material and Method: Based on the participants’ medical history, physical examination and radiological examination, sixty five patients were diagnosed with cervical disc herniation. Twenty patients who met the inclusion criteria were completed the study. Vertebral artery and carotid artery doppler ultrasonography was performed in these patients, thus any stenosis or insufficiency in vascular systems of the neck was evaluated. Additionally; vertebral blood flow rate (ml / min),vessel diameter(mm), minimum blood flow velocity (Vmin) and maximum blood flow velocity (Vmax) parameters was measured by doppler ultrasonography. The obtained findings compared with patients' level of pain measured with the "VAS (Visual Analog Scale)" and the level of daily life activities measured by the "Neck Disability Index ". &#x0D; Results: It was detected a statistically significant negative correlation between the VAS score and right vertebral artery diameter (p=0.019, r=-0.518). A significant reverse correlation between the VAS score and right vertebral arterial blood flow rate (p=0.011, r=-0.556) was also observed. No correlation was found between other vertebral artery parameters and VAS score or Neck Disability Index (p&gt;0.05).&#x0D; Conclusion: The findings of this study revealed that there is a correlation between the vertebral artery flow rate and pain level. Clinicians must take into consideration vertebral pathologies in patients with neck pain because of this vital condition may accompany with various musculoskeletal pathologies such as cervical disc herniation.

Association between the vertebrobasilar artery geometry and basilar artery plaques determined by high-resolution magnetic resonance imaging

BackgroundAtherosclerotic plaques are often present in regions of arteries with complicated flow patterns. Vascular morphology plays important role in hemodynamics. In this study, we investigated the relationship between the geometry of the vertebrobasilar artery system and presence of basilar artery (BA) plaque.MethodsWe enrolled 290 patients with posterior circulation ischemic stroke. We distinguished four configurations of the vertebrobasilar artery: Walking, Tuning Fork, Lambda, and No Confluence. Patients were divided into multi-bending (≥ 3 bends) and oligo-bending (< 3 bends) VA groups. The diameter of the vertebral artery (VA) and the number of bends in the intracranial VA segment were assessed using three-dimensional time-of-flight magnetic resonance angiography. High-resolution magnetic resonance imaging was used to evaluate BA plaques. Logistic regression models were used to determine the relationship between the geometry type and BA plaque prevalence.ResultsAfter adjusting for sex, age, body mass index ≥ 28, hypertension, and diabetes mellitus, the Walking, Lambda, and No Confluence geometries were associated with the presence of BA plaque (all p < 0.05). Patients with multi-bending VAs in both the Walking (20/28, 71.43% vs. 6/21, 28.57%, p = 0.003) and Lambda group (19/47, 40.43% vs. 21/97, 21.65%, p = 0.018) had more plaques compared to patients with oligo-bending VAs in these groups. In the Lambda group, the difference in diameter of bilateral VAs was larger in patients with BA plaques than that in patients without BA plaques (1.4 mm [IQR: 0.9–1.6 mm] vs. 0.9 mm [IQR: 0.6–1.3 mm], p < 0.001).ConclusionsThe Walking, Lambda, and No Confluence geometry, ≥ 3 bends in the VAs, and a large diameter difference between bilateral VAs are associated with the presence of BA plaque.

Morphologic Changes in the Vertebral Artery Subsequent to Cervical Spine Degeneration and Aging: Analyses by Computed Tomography Angiography Using Multiplanar and 3-Dimensional Reconstructions

To identify the morphologic changes in the vertebral artery (VA) subsequent to cervical spine degeneration and aging and to investigate the risk factors for iatrogenic VA injury or occlusion. Eighty-eight consecutive patients (176 bilateral VAs) were retrospectively analyzed using radiographs, computed tomography, and computed tomography angiography images. The Kellgren and Lawrence (KL) score and its modified subscores were used to grade the severity of degenerative changes in the cervical spine. VA tortuosity widths and diameters were measured between the C2 and C6 transverse foramens. The outcome measures were statistically analyzed for difference, correlation, and explanatory variable. The level with a high prevalence of VA stenosis was also evaluated. There were significant positive correlations between the KL score and VA tortuosity width, and between age and VA tortuosity width. Osteophyte formation in the facet joint was the predominant explanatory variable for medial deviation of the VA. Significant positive correlations were evident between the dominant VA diameter and KL score or age. VA stenosis occurred at C3/C4 (24.5%) with the highest prevalence and it was caused by uncovertebral joint osteophytes (52.0%) with the highest incidence. The present study provides important evidence for decisions of surgical strategy and for avoiding catastrophic VA injury or occlusion in cervical spine surgeries.

Are the Morphological Indices of the Vertebrobasilar System Heritable? A Twin Study Based on 3D Reconstructed Models.

Background and Objectives: The asymmetrical vertebral artery (VA) flow and diameter are common findings, which can result in an asymmetrical blood flow in the basilar artery (BA), leading to bending of the artery over time. This study investigated whether the variation of the different vertebrobasilar morphological indices that influence flow characteristics might be inherited. Materials and Methods: We analyzed 200 cerebral magnetic resonance imaging (MRI) scans of healthy Caucasian twins (100 pairs) who underwent time-of-flight MRI. From the scans, we reconstructed the 3D mesh of the posterior circulation from the start of the V4 segment to the basilar tip and subsequently analyzed the morphology of the vertebrobasilar system. The phenotypic covariances of the different morphological parameters were decomposed into heritability (A), shared (C), and unshared (E) environmental effects. Results: 39% of the twins had left dominant VA, while 32.5% had right dominant. In addition, 28.5% were classified as equal. The vertebral artery V4 segment diameter, curvature, and tortuosity were mainly influenced by shared (C) and unshared (E) environmental factors. A moderate heritability was found for the BA length (A: 63%; 95% CI: 45.7–75.2%; E: 37%; 95% CI: 24.8–54.3%) and volume (A: 60.1%; 95% CI: 42.4–73.2%; E: 39.9%; 95% CI: 26.8–57.6%), while the torsion of both arteries showed no heritability and were only influenced by the unshared environment. Conclusions: The length and volume of the BA show a moderate genetical influence. However, most of the measured morphological indices were influenced by shared and unshared factors, which highlight the role of the ever-changing hemodynamic influences shaping the geometry of the vertebrobasilar system.

Immediate effects of neuromuscular joint facilitation treatment on vertebral artery blood flow.

[Purpose] The purpose of this study was to investigate the changes in blood flow velocity and the vascular diameter of vertebral arteries before and after neuromuscular joint facilitation interventions via the cervical spine approach in healthy adults. [Participants and Methods] We included 16 healthy adults (9 males and 7 females). The interventions were performed successively, separated by a one-week interval. The order of interventions was randomized. The blood-flow velocity and diameter of the vertebral artery were measured before and after the intervention. The neuromuscular joint facilitation group underwent neuromuscular joint facilitation neck flexion pattern and extension pattern training on the right side of the cervical spine, while the control group was asked to rest for 5 min. [Results] The neuromuscular joint facilitation group showed a significant increase in systolic blood flow velocity and mean blood flow velocity of the right vertebral artery after the intervention. In contrast, the control group showed no significant differences for any of the measured parameters after the intervention. [Conclusion] Neuromuscular joint facilitation intervention via the cervical spine approach may be recommended to improve vertebral artery function.

Target Embolization of Dilated Post-PICA Segment for Ruptured PICA-Involved Type Vertebral Artery Dissecting Aneurysm.

In parent artery occlusion (PAO) for ruptured vertebral artery dissecting aneurysms (RVADA), target embolization using coils in a short segment to occlude only the vasodilated area containing the rupture point is selected as a first-choice procedure at our institute. We focused on RVADA involving the posterior inferior cerebellar artery (PICA) and evaluated the treatment results. This study consisted of eight cases with RVADA involving the PICA which were treated between October 2007 and January 2020. Based on radiological findings such as the bleb, the rupture points were located at the affected vertebral artery (VA) distal to PICA in all cases. Target embolization, by which only coiling at the dilated segment distal to the VA was performed. We aimed to preserve blood flow to the PICA. The incidence and extent of medullary infarctions, and neurological outcome were retrospectively assessed. Regarding the diameter of bilateral VA, there were no differences in six cases while the affected VA with RVADA were larger in the remaining two cases. PICA was preserved in all cases but one in which occlusion of complementary PICA was observed. Postoperative medullary infarction was not noted. There was no rebleeding during the follow-up period. However, recanalization of the VA was observed in four cases and additional coil embolization was performed. All patients were discharged with a good outcome (modified Rankin Scale [mRS] 0; seven patients, mRS 2; one patient). Target embolization preserving the PICA in PICA-involved type RVADA was considered to be an effective treatment method for cases whose rupture point was located in the VA distal to PICA orifice.

Respiratory alkalinization and posterior cerebral artery dilatation predict acute mountain sickness severity during 10h normobaric hypoxia.

What is the central question of this study? The pathophysiology of acute mountain sickness (AMS), involving the respiratory, renal and cerebrovascular systems, remains poorly understood. How do the early adaptations in these systems during a simulated altitude of 5000m relate to AMS risk? What is the main finding and its importance? The rate of blood alkalosis and cerebral artery dilatation predict AMS severity during the first 10 h of exposure to a simulated altitude of 5000m. Slow metabolic compensation by the kidneys of respiratory alkalosis attributable to a brisk breathing response together with excessive brain blood vessel dilatation might be involved in early development of AMS. The complex pathophysiology of acute mountain sickness (AMS) remains poorly understood and is likely to involve maladaptive responses of the respiratory, renal and cerebrovascular systems to hypoxia. Using stepwise linear regression, we tested the hypothesis that exacerbated respiratory alkalosis, as a result of a brisk ventilatory response, sluggish renal compensation in acute hypoxia and dysregulation of cerebral perfusion predict AMS severity. We assessed the Lake Louise score (LLS, an index of AMS severity), fluid balance, ventilation, venous pH, bicarbonate, sodium and creatinine concentrations, body weight, urinary pH and cerebral blood flow [internal carotid artery (ICA) and vertebral artery (VA) blood flow and diameter], in 27 healthy individuals (13 women) throughout 10h exposures to normobaric normoxia (fraction of inspired O2 = 0.21) and normobaric hypoxia (fraction of inspired O2 = 0.117, simulated 5000m) in a randomized, single-blinded manner. In comparison to normoxia, hypoxia increased the LLS, ventilation, venous and urinary pH, and blood flow and diameter in the ICA and VA, while venous concentrations of both bicarbonate and creatinine were decreased (P<0.001 for all). There were significant correlations between AMS severity and the rates of change in blood pH, sodium concentration and VA diameter and more positive fluid balance (P<0.05). Stepwise regression found increased blood pH [beta coefficient (β) = 0.589, P<0.001] and VA diameter (β = 0.418, P = 0.008) to be significant predictors of AMS severity in our cohort [F(2, 20) = 16.1, R2 = 0.617, P<0.001, n = 24], accounting for 62% of the variance in peak LLS. Using classic regression variable selection, our data implicate the degree of respiratory alkalosis and cerebrovascular dilatation in the early stages of AMS development.

Coexistence of posterior cerebral circulation anatomical variations and basilar artery aneurysms: Case-control study.

B a c k g r o u n d: The anatomy of arteries supplying blood to the brain often varies among the population. It applies particularly to posterior cerebral circulation. The impact of its anatomy variabilities on the formation of intracranial aneurysms has not been determined yet. The aim was to find out if posterior cerebral circulation anatomy variations coexist with basilar artery aneurysms (BAAs). We retrospectively analyzed 27 patients with BAA and a group of 30 patients matched by gender and age but without BAA. In both groups together most (66.67%) of patients were female and the average age was 59.75 ± 10.91. All of the patients had Computed Tomography performed. We assessed the occurrence of BAA, basilar artery (BA) diameter, vertebral artery (VA) diameter, posterior cerebral artery (PCA) diameter, and if patients had hypoplastic VA or PCA. Results: The presence of right VA hypoplasia significantly increased the risk of BAA occurrence (48.15% vs. 16.67%; p = 0.011). The occurrence of hypoplastic VA on either side was significantly associated with the risk of BAA formation (59.26% vs. 26.67%; p = 0.013). Patients with BAA had slightly larger left PCA diameter 1cm after division (1.96 ± 0.51 vs. 1.64 ± 0.42; p = 0.014) in comparison to those without BAA. Additionally, hypoplastic right PCA occurred more often in patients with BAA (22.22% vs. 0%; p = 0.022). Conclusions: We can conclude that the anatomy of PCA and VA affects the occurrence of BAA. Hypoplastic VA, the presence of wider left PCA and hypoplastic right PCA may be factors that coexist with BAA occurrence.

Feasibility of evaluating the stenosis of intracranial segment in the vertebral artery using neck-brain integrated ultrasound: a comparison with computed tomography angiography and digital subtraction angiography.

BackgroundCurrently, no clear diagnostic indicator of vertebral artery hypoplasia (VAH) or intracranial stenosis exists in clinic. This study aims to study the feasibility of neck-brain integrated ultrasound for evaluating stenosis of the intracranial segment in the vertebral artery by comparing with those of computed tomography angiography (CTA) and digital subtraction angiography (DSA).MethodsClinical data of 138 patients who presented to our hospital with dizziness and headache as the main symptoms between April 2018 and June 2019 were retrospectively analyzed. Patients were divided into observation group and unilateral VAH group. The diagnosing accuracy of ultrasound, CTA, and DAS, the vertebral artery diameter (VAD), blood flow, end diastolic velocity (EDV), peak systolic velocity (PSV) values, resistance indexes (RIs), and difference of RI were compared between the two groups. The sensitivity, specificity and accuracy of ultrasound hemodynamic indicators in assessing stenosis of the intracranial segment of the vertebral artery were calculated.ResultsThe accuracy rates of mild stenosis and non-stenosis with neck-brain integrated ultrasound were significantly different from those with CTA and DSA examination (P<0.05). The VAD, blood flow, EDV and PSV values of the affected side in the observation group were lower than those of the VAH side in the unilateral VAH group, while the RI and RI difference value were significantly higher than the unilateral VAH group (P<0.05). When the predicted boundary value was 2.084 mm (VAD), 56.41 mL/min (blood flow), 8.47 cm/s (EDV), 0.743 (RI), and 0.149 (difference of RI), the sensitivity and specificity were (86.43%, 49.45%), (88.67%, 47.42%), (80.47%, 68.71%), (82.71%, 84.66%), and (95.84%, 80.11%), respectively.ConclusionsNeck-brain integrated ultrasound is of great value as a noninvasive examination in the diagnosis of stenotic lesions of the internal cervical vertebral artery. VAD, EDV, blood flow, RI, and the difference in RI can be used as indicators to evaluate stenosis of the internal carotid segment of the vertebral artery and provide a reliable basis for the clinical diagnosis of posterior circulation ischemia.

Vertebral Artery Terminating Posterior Inferior Cerebellar Artery (PICA-VA) as a Potential Risk Factor in Cervical Spine Surgery

Unilateral vertebral artery (VA) injury is thought to not result in serious complications. The dominant-side VA should be preserved, although the importance of the nondominant-side VA has not been discussed. The injury of VA terminating posterior inferior cerebellar artery (PICA-VA) may result in cerebellar infarction. The characteristics of PICA-VA were evaluated. In study 1, results of head and neck magnetic resonance angiography were reviewed for 358 consecutive cases. VA diameter was measured at the V2 segment. Relationships between frequency of PICA-VA and asymmetry and diameter of the VA were analyzed. In study 2, results of magnetic resonance angiography were measured for 62 consecutive cases aged ≤39 years. Frequency of PICA-VA was compared between this young age group and 324 of the 358 cases aged ≥50 years. Mean age for the total cohort was 67.8 ± 13.8 years (range, 10-94 years). PICA-VA was identified in 44 cases (12.3%). Mean diameter of all VAs was 3.2 ± 0.76 mm. Mean diameter of PICA-VA was 2.0 ± 0.55 mm, significantly smaller than the nondominant side in Confluence (+) (2.8 ± 0.59 mm; P < 0.001). Among the 56 VAs <2.0 mm, 26 (46.4%) were PICA-VA. PICA-VA was seen in 1 of the 62 cases aged ≤39 years (1.6%), and in 43 of the 324 cases aged ≥50 years (13.3%), showing a significantly lower frequency in the younger population (P < 0.001). Whether PICA-VA injury causes complications is not obvious. However, PICA-VA should also be preserved considering that potential risks exist. If the VA is small or shows a large difference in diameter between sides, special care should be taken during cervical spine surgery.

Internal carotid and vertebral arteries diameters and their interrelationships to sex and left/right side.

The available anatomical data about diameters of inflow vessels to the circle of Willis reflect various diagnostic and imaging methods used, sample sizes, levels of measurements, and lack of possible specific ethnic, regional or genetic data. Additionally, the data are often without distinctions about left-right or sex. Therefore, using computed tomography angiography (CTA) we investigated diameters of internal carotid (ICA) and vertebral (VA) arteries in 70 adult persons (28-75 years) of both sexes (34 males and 36 females), at predefined cervical parts of ICA (2 cm above carotid bifurcation) and of VA (5 mm before VA penetrated the dura). Sex differences were expressed as highly significant larger diameters of left VA (LVA) in males (3.49 mm) than in females (3.00 mm), and as significantly larger diameters of right VA (RVA) in males (3.20 mm) than in females (2.82 mm), as well as of right ICA (RICA) diameters in males (5.04 mm) than in females (4.56 mm), but without such difference for left ICA (LICA) between males (4.82 mm) and females (4.60 mm). Intrasex (in males or in females) left-right differences of ICA and VA diameters were not significant. Significant positive correlations were found in females between RICA and RVA, and in males between RICA and LICA. Calculated mean sum of ipsilateral diameters of right arteries (RAA = RICA + RVA) was in males 8.25 mm, in females 7.38 mm, and of left arteries (LAA = LICA + LVA) was in males 8.31, and in females 7.60 mm, without statistically significant difference between RAA and LAA, neither in males, nor in females. Statistically highly significant larger sums of diameters were in males than in females for both, RAA and LAA. Our findings, as the first data about diameters of ICA and VA systematically obtained by CTA in the population of western Balkans, suggest that in the studies of these diameters is absolutely necessary to analyse separately the data for sex, and to use defined standard levels.