EFFECT OF DRY IMMERSION ON BLOOD FLOW IN JUGULAR VEINS AND CEREBRAL VENOUS SINUS: ULTRASONIC METHODS OF INVESTIGATION

Abstract Purpose Neuro-ophthalmological changes defined as spaceflight-associated neuro-ocular syndrome have been reported after long duration space flights. The pathophysiology of this syndrome remains unclear, with the possible involvement of elevated intracranial pressure. Changes in blood flow in the brain, evaluated indirectly by Doppler, have been reported in flight. However, the effects of microgravity on regional cerebral blood flow (rCBF) are not known. We therefore investigated changes in rCBF in a 5-day dry immersion (DI) model. Moreover, we tested thigh cuffs as a countermeasure to prevent potential microgravity-induced modifications in rCBF.Methods 18 healthy male participants underwent 5-day DI with or without a thigh cuffs countermeasure. They were randomly allocated to a control (n = 9) or cuffs (n = 9) group. rCBF was measured 4 days before DI (Pre-DI) and at the end of the fifth day of DI (Post-DI), using single-photon emission computed tomography (SPECT) with radiopharmaceutical 99mTc-hexamethyl propylene amine oxime (HMPAO). SPECT images were processed using statistical parametric mapping (SPM12) software.Results At DI5, we observed a significant decrease in rCBF in 32 cortical and subcortical patterns, with greater hypoperfusion in the occipital region (occipital peak level: z = 4.51, puncorr < 0.001) and basal ganglia (putamen peak level: z = 4.71, puncorr < 0.001; caudate nuclei peak level: z = 3.80, puncorr < 0.001). No significant difference was found between the control and cuffs groups on variations in rCBF at DI5.Conclusion 5-day DI induces a relative decrease in rCBF in cortical and subcortical regions. Nevertheless, the consequences of this decrease for brain function and mechanisms need further investigation.

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The Hemodynamics of Blood Flow through the Internal Jugular Veins after CCSVI Endovascular Treatment and its Impact on the Quality of Life in Patients with Chronic Cerebrospinal Venous Insufficiency

Brain Disorders & Therapy ◽

10.4172/2168-975x.1000219 ◽

2016 ◽

Vol 05 (03) ◽

Cited By ~ 1

Author(s):

Jacek Kostecki ◽

Maciej Zaniewski

Keyword(s):

Quality Of Life ◽

Blood Flow ◽

Endovascular Treatment ◽

Venous Insufficiency ◽

Jugular Veins ◽

Chronic Cerebrospinal Venous Insufficiency ◽

Flow Through ◽

Internal Jugular Veins

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Effects of short-term exposure to head-down tilt on cerebral hemodynamics: a prospective evaluation of a spaceflight analog using phase-contrast MRI

Journal of Applied Physiology ◽

10.1152/japplphysiol.00841.2015 ◽

2016 ◽

Vol 120 (12) ◽

pp. 1466-1473 ◽

Cited By ~ 15

Author(s):

Karina Marshall-Goebel ◽

Khalid Ambarki ◽

Anders Eklund ◽

Jan Malm ◽

Edwin Mulder ◽

...

Keyword(s):

Blood Flow ◽

Phase Contrast ◽

Cerebral Hemodynamics ◽

Arterial Blood Flow ◽

Ambient Atmosphere ◽

Phase Contrast Mri ◽

Jugular Veins ◽

Cross Sectional ◽

Arterial Blood ◽

Short Term Exposure

Alterations in cerebral hemodynamics in microgravity are hypothesized to occur during spaceflight and could be linked to the Visual Impairment and Intracranial Pressure syndrome. Head-down tilt (HDT) is frequently used as a ground-based analog to simulate cephalad fluid shifts in microgravity; however, its effects on cerebral hemodynamics have not been well studied with MRI techniques. Here, we evaluate the effects of 1) various HDT angles on cerebral arterial and venous hemodynamics; and 2) exposure to 1% CO2 during an intermediate HDT angle (−12°) as an additional space-related environmental factor. Blood flow, cross-sectional area (CSA), and blood flow velocity were measured with phase-contrast MRI in the internal jugular veins, as well as the vertebral and internal carotid arteries. Nine healthy male subjects were measured at baseline (supine, 0°) and after 4.5 h of HDT at −6°, −12° (with and without 1% CO2), and −18°. We found a decrease in total arterial blood flow from baseline during all angles of HDT. On the venous side, CSA increased with HDT, and outflow decreased during −12° HDT ( P = 0.039). Moreover, the addition of 1% CO2 to −12° HDT caused an increase in total arterial blood flow ( P = 0.016) and jugular venous outflow ( P < 0.001) compared with −12° HDT with ambient atmosphere. Overall, the results indicate decreased cerebral blood flow during HDT, which may have implications for microgravity-induced cerebral hemodynamic changes.

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Eye-Neck Integrated Ultrasound in Idiopathic Intracranial Hypertension and Cerebral Venous Sinus Thrombosis

Frontiers in Neurology ◽

10.3389/fneur.2021.696665 ◽

2021 ◽

Vol 12 ◽

Author(s):

Li Liu ◽

Yingqi Xing ◽

Ying Chen ◽

Xiaorui Ji ◽

Jiaojiao Ge ◽

...

Keyword(s):

Blood Flow ◽

Intracranial Hypertension ◽

Idiopathic Intracranial Hypertension ◽

Sinus Thrombosis ◽

Cerebral Venous Sinus Thrombosis ◽

Venous Sinus ◽

Venous Sinus Thrombosis ◽

Hemodynamic Characteristics ◽

The Mean ◽

Increased Icp

Background: The clinical presentation of cerebral venous sinus thrombosis (CVST) overlaps with that of idiopathic intracranial hypertension (IIH), but no screening tool exists. We investigated the role of eye-neck integrated ultrasound in the diagnosis and differentiation of IIH and CVST.Methods: Twenty IIH patients, 30 CVST patients, and 40 healthy controls were retrospectively analyzed. The ultrasonographic optic nerve sheath diameter (ONSD) and hemodynamic characteristics of the internal jugular veins (IJVs) were recorded. The cerebrospinal fluid opening pressure was measured after ultrasonic examination.Results: The ONSD was significantly larger in IIH patients than in controls (4.71 ± 0.41 vs. 3.93 ± 0.24 mm, p < 0.001). The ONSD cut-off for IIH diagnosis was 4.25 mm (AUC = 0.978; 95% CI: 0.95–1.0, p < 0.001, sensitivity: 90%, specificity: 93%). In the CVST group, 22 (73.3%) patients had elevated intracranial pressure (ICP); the mean ONSD was significantly higher in patients with increased ICP than in those without (4.43 ± 0.33 vs. 3.95 ± 0.17 mm, p < 0.001). The mean blood flow volume (BFV) was significantly reduced in CVST patients (425.17 ± 349.83 mL/min) compared to that in controls (680.37 ± 233.03 mL/min, p < 0.001) and IIH patients (617.67 ± 282.96 mL/min, p = 0.008). The optimal BFV cut-off for predicting CVST was 527.28 mL/min (AUC = 0.804, 95% CI: 0.68–0.93, p < 0.001, sensitivity: 80%, specificity: 78%). The velocity of the unilateral IJVs-J3 segment decreased or remained constant during deep inspiration (abnormal respiratory modulate blood flow test, ARMT) in 32.5% of controls, with no bilateral ARMT. The prevalence of bilateral ARMT was 25% in IIH patients (χ2 = 12.9, p = 0.005) and 27% in CVST patients (χ2 = 17.6, p = 0.001).Conclusion: Eye-neck integrated ultrasound is an easily available bedside technique to assess ICP and hemodynamic characteristics of IJVs. ONSD measurement can identify patients with increased ICP, and reduced IJV BFV may aid the differentiation of CVST and IIH.

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Retrograde blood flow in the internal jugular veins of humans with hypertension may have implications for cerebral arterial blood flow

European Radiology ◽

10.1007/s00330-020-06752-6 ◽

2020 ◽

Vol 30 (7) ◽

pp. 3890-3899

Author(s):

Jonathan C. L. Rodrigues ◽

Galina Strelko ◽

Esther A. H. Warnert ◽

Amy E. Burchell ◽

Sandra Neumann ◽

...

Keyword(s):

Blood Flow ◽

Arterial Blood Flow ◽

Jugular Veins ◽

Arterial Blood ◽

Retrograde Blood Flow ◽

Internal Jugular Veins

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Jugular venous pooling during lowering of the head affects blood pressure of the anesthetized giraffe

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.90804.2008 ◽

2009 ◽

Vol 297 (4) ◽

pp. R1058-R1065 ◽

Cited By ~ 30

Author(s):

E. Brøndum ◽

J. M. Hasenkam ◽

N. H. Secher ◽

M. F. Bertelsen ◽

C. Grøndahl ◽

...

Keyword(s):

Blood Flow ◽

Cardiac Output ◽

Arterial Pressure ◽

Venous Pressure ◽

Upright Position ◽

Cross Sectional Area ◽

Sectional Area ◽

Jugular Veins ◽

Cross Sectional ◽

Spontaneously Breathing

How blood flow and pressure to the giraffe's brain are regulated when drinking remains debated. We measured simultaneous blood flow, pressure, and cross-sectional area in the carotid artery and jugular vein of five anesthetized and spontaneously breathing giraffes. The giraffes were suspended in the upright position so that we could lower the head. In the upright position, mean arterial pressure (MAP) was 193 ± 11 mmHg (mean ± SE), carotid flow was 0.7 ± 0.2 l/min, and carotid cross-sectional area was 0.85 ± 0.04 cm2. Central venous pressure (CVP) was 4 ± 2 mmHg, jugular flow was 0.7 ± 0.2 l/min, and jugular cross-sectional area was 0.14 ± 0.04 cm2 ( n = 4). Carotid arterial and jugular venous pressures at head level were 118 ± 9 and −7 ± 4 mmHg, respectively. When the head was lowered, MAP decreased to 131 ± 13 mmHg, while carotid cross-sectional area and flow remained unchanged. Cardiac output was reduced by 30%, CVP decreased to −1 ± 2 mmHg ( P < 0.01), and jugular flow ceased as the jugular cross-sectional area increased to 3.2 ± 0.6 cm2 ( P < 0.01), corresponding to accumulation of ∼1.2 l of blood in the veins. When the head was raised, the jugular veins collapsed and blood was returned to the central circulation, and CVP and cardiac output were restored. The results demonstrate that in the upright-positioned, anesthetized giraffe cerebral blood flow is governed by arterial pressure without support of a siphon mechanism and that when the head is lowered, blood accumulates in the vein, affecting MAP.

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Evidence of active regulation of cerebral venous tone in individuals undergoing embolization of brain arteriovenous malformations

Journal of Applied Physiology ◽

10.1152/japplphysiol.00951.2013 ◽

2013 ◽

Vol 115 (11) ◽

pp. 1666-1671 ◽

Cited By ~ 2

Author(s):

Alexey Y. Ivanov ◽

Andrey E. Petrov ◽

Elena A. Vershinina ◽

Michael M. Galagudza ◽

Timur D. Vlasov

Keyword(s):

Blood Flow ◽

Flow Velocity ◽

Blood Flow Velocity ◽

Arteriovenous Malformations ◽

Resistance Index ◽

Cerebral Veins ◽

Jugular Veins ◽

Cross Sectional ◽

Brain Arteriovenous Malformations ◽

Active Regulation

Cerebral venous drainage is generally believed to be regulated primarily by hydrodynamic forces. To gain further insight into the regulation of this process, we investigated the response of blood flow velocity and cross-sectional area (CSA) of the internal jugular veins (IJVs) to local hemodynamic shifts. All procedures and assessments were performed on patients ( n = 30) undergoing embolization of brain arteriovenous malformations (AVMs). The procedure efficiency was verified by the postembolization reduction in time-averaged maximum blood flow velocities, as well as the elevation of pulsatility index and resistance index in the arterial feeders. In cerebral veins, the dominant IJV pressure remained unchanged during the procedure. At the same time, AVM embolization caused a significant reduction in maximal CSA (84 ± 7.6 to 68 ± 7.7 mm2, P < 0.05) and minimal CSA (68 ± 7.0 to 51 ± 7.0 mm2, P < 0.01) of the IJV located ipsilateral to the AVM, while the maximal linear blood flow velocity in the IJV remained unchanged (71 ± 4.9 and 85 ± 8.4 cm/s, P = 0.098). Consistent with previously published studies, the data obtained provide further evidence of active regulation of the venous outflow, probably mediated by certain neurogenic and/or endothelium-dependent mechanisms.

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Venous sinus stenting for intractable pulsatile tinnitus: A review of indications and outcomes

Surgical Neurology International ◽

10.25259/sni_1_2021 ◽

2021 ◽

Vol 12 ◽

pp. 81

Author(s):

Brian Fiani ◽

Athanasios Kondilis ◽

Thao Doan ◽

Juliana Runnels ◽

Nicholas J. Fiani ◽

...

Keyword(s):

Blood Flow ◽

Endovascular Treatment ◽

Venous Sinus ◽

High Rate ◽

Structural Abnormality ◽

Conscious Perception ◽

Pulsatile Tinnitus ◽

Effective Treatment Option ◽

Pubmed Database ◽

Unique Variation

Background: Pulsatile tinnitus presents as a unique variation of tinnitus in which a conscious perception of the heartbeat is localized to the ears in either unilateral or bilateral fashion. The sensation is typically caused by an increase in turbulent blood flow in the affected ear, in most cases, due to a structural abnormality of the venous sinuses – the most common of which being stenosis. Herein, we discuss the etiology of pulsatile tinnitus followed by indications for treatment of various pathologies which have been successfully treated with venous sinus stenting and have led to resolution of auditory symptoms. Methods: The authors queried PubMed database using combinations of the keywords “venous sinus stenting,” “endovascular treatment,” and “pulsatile tinnitus” to identify relevant studies published in English after 2001 and before December 1, 2020 and verified selected. Results: Our results corroborate those published in prior reviews reporting a high rate of pulsatile tinnitus resolution with venous sinus stenting. Conclusion: The success of venous sinus stenting is clinically relevant as an effective treatment option for patients suffering from pulsatile tinnitus. Future applications and studies are needed and are currently being developed to further demonstrate the effectiveness of stents in the treatment of pulsatile tinnitus.

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