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Sincomb S, Moral-Pulido F, Campos O, Martínez-Bazán C, Haughton V, Sánchez A. An in vitro experimental investigation of oscillatory flow in the cerebral aqueduct. EUROPEAN JOURNAL OF MECHANICS. B, FLUIDS 2024; 105:180-191. [PMID: 38770034 PMCID: PMC11105671 DOI: 10.1016/j.euromechflu.2024.01.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
This in vitro study aims at clarifying the relation between the oscillatory flow of cerebrospinal fluid (CSF) in the cerebral aqueduct, a narrow conduit connecting the third and fourth ventricles, and the corresponding interventricular pressure difference. Dimensional analysis is used in designing an anatomically correct scaled model of the aqueduct flow, with physical similarity maintained by adjusting the flow frequency and the properties of the working fluid. The time-varying pressure difference across the aqueduct corresponding to a given oscillatory flow rate is measured in parametric ranges covering the range of flow conditions commonly encountered in healthy subjects. Parametric dependences are delineated for the time-averaged pressure fluctuations and for the phase lag between the transaqueductal pressure difference and the flow rate, both having clinical relevance. The results are validated through comparisons with predictions obtained with a previously derived computational model. The parametric quantification in this study enables the derivation of a simple formula for the relation between the transaqueductal pressure and the stroke volume. This relationship can be useful in the quantification of transmantle pressure differences based on non-invasive magnetic-resonance-velocimetry measurements of aqueduct flow for investigation of CSF-related disorders.
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Affiliation(s)
- S. Sincomb
- Department of Aerospace and Mechanical Engineering, University of California, San Diego, La Jolla, 92093-0411, CA, USA
| | - F. Moral-Pulido
- Department of Mechanical and Mining Engineering, University of Jaen, Jaen, 23071, Spain
- Andalusian Institute for Earth System Research, University of Jaen, Jaen, 23071, Spain
| | - O. Campos
- Department of Aerospace and Mechanical Engineering, University of California, San Diego, La Jolla, 92093-0411, CA, USA
| | - C. Martínez-Bazán
- Department of Mechanics of Structures and Hydraulic Engineering, University of Granada, Granada, 18001, Spain
- Andalusian Institute for Earth System Research, University of Granada, Granada, 18006, Spain
| | - V. Haughton
- School of Medicine and Public Health, University of Wisconsin-Madison, Madison, 53706, WI, USA
| | - A.L. Sánchez
- Department of Aerospace and Mechanical Engineering, University of California, San Diego, La Jolla, 92093-0411, CA, USA
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Seubert ME, Goeijenbier M. Controlled Mechanical Ventilation in Critically Ill Patients and the Potential Role of Venous Bagging in Acute Kidney Injury. J Clin Med 2024; 13:1504. [PMID: 38592687 PMCID: PMC10934139 DOI: 10.3390/jcm13051504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 02/29/2024] [Accepted: 03/02/2024] [Indexed: 04/10/2024] Open
Abstract
A very low incidence of acute kidney injury (AKI) has been observed in COVID-19 patients purposefully treated with early pressure support ventilation (PSV) compared to those receiving mainly controlled ventilation. The prevention of subdiaphragmatic venous congestion through limited fluid intake and the lowering of intrathoracic pressure is a possible and attractive explanation for this observed phenomenon. Both venous congestion, or "venous bagging", and a positive fluid balance correlate with the occurrence of AKI. The impact of PSV on venous return, in addition to the effects of limiting intravenous fluids, may, at least in part, explain this even more clearly when there is no primary kidney disease or the presence of nephrotoxins. Optimizing the patient-ventilator interaction in PSV is challenging, in part because of the need for the ongoing titration of sedatives and opioids. The known benefits include improved ventilation/perfusion matching and reduced ventilator time. Furthermore, conservative fluid management positively influences cognitive and psychiatric morbidities in ICU patients and survivors. Here, it is hypothesized that cranial lymphatic congestion in relation to a more positive intrathoracic pressure, i.e., in patients predominantly treated with controlled mechanical ventilation (CMV), is a contributing risk factor for ICU delirium. No studies have addressed the question of how PSV can limit AKI, nor are there studies providing high-level evidence relating controlled mechanical ventilation to AKI. For this perspective article, we discuss studies in the literature demonstrating the effects of venous congestion leading to AKI. We aim to shed light on early PSV as a preventive measure, especially for the development of AKI and ICU delirium and emphasize the need for further research in this domain.
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Affiliation(s)
- Mark E. Seubert
- Department of Intensive Care, HagaZiekenhuis, 2725 NA Zoetermeer, The Netherlands
| | - Marco Goeijenbier
- Department of Intensive Care, Spaarne Gasthuis, 2035 RC Haarlem, The Netherlands;
- Department of Intensive Care, Erasmus MC, 3015 CN Rotterdam, The Netherlands
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3
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Piersanti E, Rognes ME, Vinje V. Are brain displacements and pressures within the parenchyma induced by surface pressure differences? A computational modelling study. PLoS One 2023; 18:e0288668. [PMID: 38150460 PMCID: PMC10752538 DOI: 10.1371/journal.pone.0288668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 06/30/2023] [Indexed: 12/29/2023] Open
Abstract
The intracranial pressure is implicated in many homeostatic processes in the brain and is a fundamental parameter in several diseases such as e.g. idiopathic normal pressure hydrocephalus. The presence of a small but persistent pulsatile intracranial pulsatile transmantle pressure gradient (on the order of a few mmHg/m at peak) has recently been demonstrated in hydrocephalus subjects. A key question is whether pulsatile intracranial pressure and displacements can be induced by a small pressure gradient originating from the brain surface alone. In this study, we model the brain parenchyma as either a linearly elastic or a poroelastic medium, and impose a pulsatile pressure gradient acting between the ventricular and the pial surfaces but no additional external forces. Using this high-resolution physics-based model, we use in vivo pulsatile pressure gradients from subjects with idiopathic normal pressure hydrocephalus to compute parenchyma displacement, volume change, fluid pressure, and fluid flux. The resulting displacement field is pulsatile and in qualitatively and quantitatively good agreement with the literature, both with elastic and poroelastic models. However, the pulsatile forces on the boundaries are not sufficient for pressure pulse propagation through the brain parenchyma. Our results suggest that pressure differences at the brain surface, originating e.g. from pulsating arteries surrounding the brain, are not alone sufficient to drive interstitial fluid flow within the brain parenchyma and that potential pressure gradients found within the parenchyma rather arise from a large portion of the blood vessel network, including smaller blood vessels within the brain parenchyma itself.
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Affiliation(s)
- Eleonora Piersanti
- Simula Research Laboratory, Oslo, Norway
- Expert Analytics AS, Oslo, Norway
| | | | - Vegard Vinje
- Simula Research Laboratory, Oslo, Norway
- Expert Analytics AS, Oslo, Norway
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Helakari H, Järvelä M, Väyrynen T, Tuunanen J, Piispala J, Kallio M, Ebrahimi SM, Poltojainen V, Kananen J, Elabasy A, Huotari N, Raitamaa L, Tuovinen T, Korhonen V, Nedergaard M, Kiviniemi V. Effect of sleep deprivation and NREM sleep stage on physiological brain pulsations. Front Neurosci 2023; 17:1275184. [PMID: 38105924 PMCID: PMC10722275 DOI: 10.3389/fnins.2023.1275184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 11/02/2023] [Indexed: 12/19/2023] Open
Abstract
Introduction Sleep increases brain fluid transport and the power of pulsations driving the fluids. We investigated how sleep deprivation or electrophysiologically different stages of non-rapid-eye-movement (NREM) sleep affect the human brain pulsations. Methods Fast functional magnetic resonance imaging (fMRI) was performed in healthy subjects (n = 23) with synchronous electroencephalography (EEG), that was used to verify arousal states (awake, N1 and N2 sleep). Cardiorespiratory rates were verified with physiological monitoring. Spectral power analysis assessed the strength, and spectral entropy assessed the stability of the pulsations. Results In N1 sleep, the power of vasomotor (VLF < 0.1 Hz), but not cardiorespiratory pulsations, intensified after sleep deprived vs. non-sleep deprived subjects. The power of all three pulsations increased as a function of arousal state (N2 > N1 > awake) encompassing brain tissue in both sleep stages, but extra-axial CSF spaces only in N2 sleep. Spectral entropy of full band and respiratory pulsations decreased most in N2 sleep stage, while cardiac spectral entropy increased in ventricles. Discussion In summary, the sleep deprivation and sleep depth, both increase the power and harmonize the spectral content of human brain pulsations.
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Affiliation(s)
- Heta Helakari
- Oulu Functional Neuroimaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland
- Research Unit of Health Sciences and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland
| | - Matti Järvelä
- Oulu Functional Neuroimaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland
- Research Unit of Health Sciences and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland
| | - Tommi Väyrynen
- Oulu Functional Neuroimaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland
- Research Unit of Health Sciences and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland
| | - Johanna Tuunanen
- Oulu Functional Neuroimaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland
- Research Unit of Health Sciences and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland
| | - Johanna Piispala
- Clinical Neurophysiology, Oulu University Hospital, Oulu, Finland
| | - Mika Kallio
- Clinical Neurophysiology, Oulu University Hospital, Oulu, Finland
| | - Seyed Mohsen Ebrahimi
- Oulu Functional Neuroimaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland
- Research Unit of Health Sciences and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland
| | - Valter Poltojainen
- Oulu Functional Neuroimaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland
- Research Unit of Health Sciences and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland
| | - Janne Kananen
- Oulu Functional Neuroimaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland
- Research Unit of Health Sciences and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland
- Clinical Neurophysiology, Oulu University Hospital, Oulu, Finland
| | - Ahmed Elabasy
- Oulu Functional Neuroimaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland
- Research Unit of Health Sciences and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland
| | - Niko Huotari
- Oulu Functional Neuroimaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland
- Research Unit of Health Sciences and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland
| | - Lauri Raitamaa
- Oulu Functional Neuroimaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland
- Research Unit of Health Sciences and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland
| | - Timo Tuovinen
- Oulu Functional Neuroimaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland
- Research Unit of Health Sciences and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland
| | - Vesa Korhonen
- Oulu Functional Neuroimaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland
- Research Unit of Health Sciences and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland
| | - Maiken Nedergaard
- Center of Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
- Center of Translational Neuromedicine, University of Rochester, Rochester, NY, United States
| | - Vesa Kiviniemi
- Oulu Functional Neuroimaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland
- Research Unit of Health Sciences and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland
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Taylor Z, English C, Cramberg M, Young BA. The influence of spinal venous blood pressure on cerebrospinal fluid pressure. Sci Rep 2023; 13:20989. [PMID: 38017027 PMCID: PMC10684553 DOI: 10.1038/s41598-023-48334-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 11/25/2023] [Indexed: 11/30/2023] Open
Abstract
In Alligator mississippiensis the spinal dura is surrounded by a venous sinus; pressure waves can propagate in the spinal venous blood, and these spinal venous pressures can be transmitted to the spinal cerebrospinal fluid (CSF). This study was designed to explore pressure transfer between the spinal venous blood and the spinal CSF. At rest the cardiac-related CSF pulsations are attenuated and delayed, while the ventilatory-related pulsations are amplified as they move from the spinal venous blood to the spinal CSF. Orthostatic gradients resulted in significant alterations of both cardiac- and ventilatory-related CSF pulsations. Manual lateral oscillations of the alligator's tail created pressure waves in the spinal CSF that propagated, with slight attenuation but no delay, to the cranial CSF. Oscillatory pressure pulsations in the spinal CSF and venous blood had little influence on the underlying ventilatory pulsations, though the same oscillatory pulsations reduced the ventilatory- and increased the cardiac-related pulsations in the cranial CSF. In Alligator the spinal venous anatomy creates a more complex pressure relationship between the venous and CSF systems than has been described in humans.
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Affiliation(s)
- Z Taylor
- Department of Anatomy, Kirksville College of Osteopathic Medicine, Kirksville, MO, 63501, USA
| | - C English
- Department of Anatomy, Kirksville College of Osteopathic Medicine, Kirksville, MO, 63501, USA
| | - M Cramberg
- Department of Anatomy, Kirksville College of Osteopathic Medicine, Kirksville, MO, 63501, USA
| | - B A Young
- Department of Anatomy, Kirksville College of Osteopathic Medicine, Kirksville, MO, 63501, USA.
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Riedel CS, Martinez-Tejada I, Andresen M, Wilhjelm JE, Jennum P, Juhler M. Transient intracranial pressure elevations (B waves) are associated with sleep apnea. Fluids Barriers CNS 2023; 20:69. [PMID: 37784168 PMCID: PMC10544378 DOI: 10.1186/s12987-023-00469-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 09/17/2023] [Indexed: 10/04/2023] Open
Abstract
BACKGROUND Repetitive transient intracranial pressure waveform elevations up to 50 mmHg (ICP B-waves) are often used to define pathological conditions and determine indications for ICP-reducing treatment. We recently showed that nocturnal transient ICP elevations are present in patients without structural brain lesions or hydrocephalus in whom they are associated with sleep apnea. However, whether this signifies a general association between ICP macropatterns and sleep apnea remains unknown. METHODS We included 34 patients with hydrocephalus, or idiopathic intracranial hypertension (IIH), who were referred to the Neurosurgical Department, Copenhagen, Denmark, from 2017 to 2021. Every patient underwent diagnostic overnight ICP monitoring for clinical indications, with simultaneous polysomnography (PSG) sleep studies. All transient ICP elevations were objectively quantified in all patients. Three patients were monitored with continuous positive airway pressure (CPAP) treatment for an additional night. RESULTS All patients had transient ICP elevations associated with sleep apnea. The mean temporal delay from sleep apnea to transient ICP elevations for all patients was 3.6 s (SEM 0.2 s). Ramp-type transient ICP elevations with a large increase in ICP were associated with rapid eye movement (REM) sleep and sinusoidal-type elevations with non-REM (NREM) sleep. In three patients treated with CPAP, the treatment reduced the number of transient ICP elevations with a mean of 37%. CPAP treatment resulted in insignificant changes in the average ICP in two patients but elevated the average ICP during sleep in one patient by 5.6 mmHg. CONCLUSION The findings suggest that sleep apnea causes a significant proportion of transient ICP elevations, such as B-waves, and sleep apnea should be considered in ICP evaluation. Treatment of sleep apnea with CPAP can reduce the occurrence of transient ICP elevations. More research is needed on the impact of slow oscillating mechanisms on transient ICP elevations during high ICP and REM sleep.
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Affiliation(s)
- Casper Schwartz Riedel
- Department of Neurosurgery, Copenhagen University Hospital, Rigshospitalet, Inge Lehmanns Vej 6, Copenhagen East, 2100 Copenhagen, Denmark
- Danish Center for Sleep Medicine, Department of Clinical Neurophysiology, Copenhagen University Hospital, Rigshospitalet, Glostrup, Denmark
| | - Isabel Martinez-Tejada
- Department of Neurosurgery, Copenhagen University Hospital, Rigshospitalet, Inge Lehmanns Vej 6, Copenhagen East, 2100 Copenhagen, Denmark
- Department of Health Technology, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Morten Andresen
- Department of Neurosurgery, Copenhagen University Hospital, Rigshospitalet, Inge Lehmanns Vej 6, Copenhagen East, 2100 Copenhagen, Denmark
| | - Jens E. Wilhjelm
- Department of Health Technology, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Poul Jennum
- Danish Center for Sleep Medicine, Department of Clinical Neurophysiology, Copenhagen University Hospital, Rigshospitalet, Glostrup, Denmark
- Institute of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Marianne Juhler
- Department of Neurosurgery, Copenhagen University Hospital, Rigshospitalet, Inge Lehmanns Vej 6, Copenhagen East, 2100 Copenhagen, Denmark
- Institute of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
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Sætra MJ, Ellingsrud AJ, Rognes ME. Neural activity induces strongly coupled electro-chemo-mechanical interactions and fluid flow in astrocyte networks and extracellular space-A computational study. PLoS Comput Biol 2023; 19:e1010996. [PMID: 37478153 PMCID: PMC10396022 DOI: 10.1371/journal.pcbi.1010996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 08/02/2023] [Accepted: 06/28/2023] [Indexed: 07/23/2023] Open
Abstract
The complex interplay between chemical, electrical, and mechanical factors is fundamental to the function and homeostasis of the brain, but the effect of electrochemical gradients on brain interstitial fluid flow, solute transport, and clearance remains poorly quantified. Here, via in-silico experiments based on biophysical modeling, we estimate water movement across astrocyte cell membranes, within astrocyte networks, and within the extracellular space (ECS) induced by neuronal activity, and quantify the relative role of different forces (osmotic, hydrostatic, and electrical) on transport and fluid flow under such conditions. We find that neuronal activity alone may induce intracellular fluid velocities in astrocyte networks of up to 14μm/min, and fluid velocities in the ECS of similar magnitude. These velocities are dominated by an osmotic contribution in the intracellular compartment; without it, the estimated fluid velocities drop by a factor of ×34-45. Further, the compartmental fluid flow has a pronounced effect on transport: advection accelerates ionic transport within astrocytic networks by a factor of ×1-5 compared to diffusion alone.
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Affiliation(s)
- Marte J. Sætra
- Department of Numerical Analysis and Scientific Computing, Simula Research Laboratory, Oslo, Norway
| | - Ada J. Ellingsrud
- Department of Numerical Analysis and Scientific Computing, Simula Research Laboratory, Oslo, Norway
| | - Marie E. Rognes
- Department of Numerical Analysis and Scientific Computing, Simula Research Laboratory, Oslo, Norway
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Boster KAS, Cai S, Ladrón-de-Guevara A, Sun J, Zheng X, Du T, Thomas JH, Nedergaard M, Karniadakis GE, Kelley DH. Artificial intelligence velocimetry reveals in vivo flow rates, pressure gradients, and shear stresses in murine perivascular flows. Proc Natl Acad Sci U S A 2023; 120:e2217744120. [PMID: 36989300 PMCID: PMC10083563 DOI: 10.1073/pnas.2217744120] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 02/15/2023] [Indexed: 03/30/2023] Open
Abstract
Quantifying the flow of cerebrospinal fluid (CSF) is crucial for understanding brain waste clearance and nutrient delivery, as well as edema in pathological conditions such as stroke. However, existing in vivo techniques are limited to sparse velocity measurements in pial perivascular spaces (PVSs) or low-resolution measurements from brain-wide imaging. Additionally, volume flow rate, pressure, and shear stress variation in PVSs are essentially impossible to measure in vivo. Here, we show that artificial intelligence velocimetry (AIV) can integrate sparse velocity measurements with physics-informed neural networks to quantify CSF flow in PVSs. With AIV, we infer three-dimensional (3D), high-resolution velocity, pressure, and shear stress. Validation comes from training with 70% of PTV measurements and demonstrating close agreement with the remaining 30%. A sensitivity analysis on the AIV inputs shows that the uncertainty in AIV inferred quantities due to uncertainties in the PVS boundary locations inherent to in vivo imaging is less than 30%, and the uncertainty from the neural net initialization is less than 1%. In PVSs of N = 4 wild-type mice we find mean flow speed 16.33 ± 11.09 µm/s, volume flow rate 2.22 ± 1.983 × 103 µm3/s, axial pressure gradient ( - 2.75 ± 2.01)×10-4 Pa/µm (-2.07 ± 1.51 mmHg/m), and wall shear stress (3.00 ± 1.45)×10-3 Pa (all mean ± SE). Pressure gradients, flow rates, and resistances agree with prior predictions. AIV infers in vivo PVS flows in remarkable detail, which will improve fluid dynamic models and potentially clarify how CSF flow changes with aging, Alzheimer's disease, and small vessel disease.
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Affiliation(s)
| | - Shengze Cai
- Institute of Cyber-Systems and Control, College of Control Science and Engineering, Zhejiang University, Hangzhou310027, Zhejiang, China
| | - Antonio Ladrón-de-Guevara
- Center for Translational Neuromedicine and Department of Neuroscience, University of Rochester Medical Center, Rochester, NY14627
| | - Jiatong Sun
- Department of Mechanical Engineering, University of Rochester, Rochester, NY14627
| | - Xiaoning Zheng
- Department of Mathematics, College of Information Science and Technology, Jinan University, Guangzhou510632, China
| | - Ting Du
- Center for Translational Neuromedicine and Department of Neuroscience, University of Rochester Medical Center, Rochester, NY14627
- School of Pharmacy, China Medical University, Shenyang, Liaoning110122, China
| | - John H. Thomas
- Department of Mechanical Engineering, University of Rochester, Rochester, NY14627
| | - Maiken Nedergaard
- Center for Translational Neuromedicine and Department of Neuroscience, University of Rochester Medical Center, Rochester, NY14627
| | - George Em Karniadakis
- Division of Applied Mathematics, Brown University, Providence, RI02912
- School of Engineering, Brown University, Providence, RI02912
| | - Douglas H. Kelley
- Department of Mechanical Engineering, University of Rochester, Rochester, NY14627
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Sincomb S, Moral-Pulido F, Campos O, Martínez-Bazán C, Haughton V, Sánchez AL. An In-Vitro Experimental Investigation of Oscillatory Flow in the Cerebral Aqueduct. RESEARCH SQUARE 2023:rs.3.rs-2757861. [PMID: 37066335 PMCID: PMC10104269 DOI: 10.21203/rs.3.rs-2757861/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Background The cerebrospinal fluid filling the ventricles of the brain moves with a cyclic velocity driven by the transmantle pressure, or instantaneous pressure difference between the lateral ventricles and the cerebral subarachnoid space. This dynamic phenomenon is of particular interest for understanding ventriculomegaly in cases of normal pressure hydrocephalus (NPH). The magnitude of the transmantle pressure is small, on the order of a few Pascals, thereby hindering direct in vivo measurements. To complement previous computational efforts, we perform here, for the first time, in vitro experiments involving an MRI-informed experimental model of the cerebral aqueduct flow. Methods Dimensional analysis is used in designing a scaled-up model of the aqueduct flow, with physical similarity maintained by adjusting the flow frequency and the properties of the working fluid. High-resolution MRI images are used to generate a 3D-printed anatomically correct aqueduct model. A programmable pump is used to generate a pulsatile flow rate signal measured from phase-contrast MRI. Extensive experiments are performed to investigate the relation between the cyclic fluctuations of the aqueduct flow rate and the transmantle pressure fluctuation over the range of flow conditions commonly encountered in healthy subjects. The time-dependent pressure measurements are validated through comparisons with predictions obtained with a previously derived computational model. Results Parametric dependences of the pressure-fluctuation amplitude and its phase lag relative to the flow rate are delineated. The results indicate, for example, that the phase lag is nearly independent on the stroke volume. A simple expression relating the mean amplitude of the interventricular pressure difference (between third and fourth ventricle) with the stroke volume of the oscillatory flow is established. Conclusions MRI-informed in-vitro experiments using an anatomically correct model of the cerebral aqueduct and a realistic flow rate have been used to characterize transmantle pressure. The quantitative results can be useful in enabling quick clinical assessments of transmantle pressure to be made from noninvasive phase contrast MRI measurements of aqueduct flow rates. The scaled-up experimental facility provides the ability to conduct future experiments specifically aimed at investigating altered CSF flow and associated transmantle pressure, as needed in connection with NPH studies.
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Affiliation(s)
- Stephanie Sincomb
- Department of Mechanical and Aerospace Engineering, University of California- San Diego, La Jolla, US
| | - Francisco Moral-Pulido
- Departamento de Ingeniería Mecánica y Minera, Universidad de Jaén, Jaén, Spain
- Andalusian Institute for Earth System Research, Universidad de Jaén, Jaén, Spain
| | - Obed Campos
- Department of Mechanical and Aerospace Engineering, University of California- San Diego, La Jolla, US
| | - Carlos Martínez-Bazán
- Departamento de Mecánica de Estructuras e Ingeniería Hidráulica, Universidad de Granada, Granada, Spain
- Andalusian Institute for Earth System Research, Universidad de Granada, Granada, Spain
| | - Victor Haughton
- School of Medicine and Public Health, University of Wisconsin, Madison, US
| | - Antonio L. Sánchez
- Department of Mechanical and Aerospace Engineering, University of California- San Diego, La Jolla, US
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10
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Liu H, Pan F, Lei X, Hui J, Gong R, Feng J, Zheng D. Effect of intracranial pressure on photoplethysmographic waveform in different cerebral perfusion territories: A computational study. Front Physiol 2023; 14:1085871. [PMID: 37007991 PMCID: PMC10060556 DOI: 10.3389/fphys.2023.1085871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 02/24/2023] [Indexed: 03/18/2023] Open
Abstract
Background: Intracranial photoplethysmography (PPG) signals can be measured from extracranial sites using wearable sensors and may enable long-term non-invasive monitoring of intracranial pressure (ICP). However, it is still unknown if ICP changes can lead to waveform changes in intracranial PPG signals.Aim: To investigate the effect of ICP changes on the waveform of intracranial PPG signals of different cerebral perfusion territories.Methods: Based on lump-parameter Windkessel models, we developed a computational model consisting three interactive parts: cardiocerebral artery network, ICP model, and PPG model. We simulated ICP and PPG signals of three perfusion territories [anterior, middle, and posterior cerebral arteries (ACA, MCA, and PCA), all left side] in three ages (20, 40, and 60 years) and four intracranial capacitance conditions (normal, 20% decrease, 50% decrease, and 75% decrease). We calculated following PPG waveform features: maximum, minimum, mean, amplitude, min-to-max time, pulsatility index (PI), resistive index (RI), and max-to-mean ratio (MMR).Results: The simulated mean ICPs in normal condition were in the normal range (8.87–11.35 mm Hg), with larger PPG fluctuations in older subject and ACA/PCA territories. When intracranial capacitance decreased, the mean ICP increased above normal threshold (>20 mm Hg), with significant decreases in maximum, minimum, and mean; a minor decrease in amplitude; and no consistent change in min-to-max time, PI, RI, or MMR (maximal relative difference less than 2%) for PPG signals of all perfusion territories. There were significant effects of age and territory on all waveform features except age on mean.Conclusion: ICP values could significantly change the value-relevant (maximum, minimum, and amplitude) waveform features of PPG signals measured from different cerebral perfusion territories, with negligible effect on shape-relevant features (min-to-max time, PI, RI, and MMR). Age and measurement site could also significantly influence intracranial PPG waveform.
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Affiliation(s)
- Haipeng Liu
- Research Centre for Intelligent Healthcare, Coventry University, Coventry, United Kingdom
| | - Fan Pan
- College of Electronics and Information Engineering, Sichuan University, Chengdu, China
| | - Xinyue Lei
- College of Electronics and Information Engineering, Sichuan University, Chengdu, China
| | - Jiyuan Hui
- Brain Injury Center, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Ru Gong
- Brain Injury Center, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Junfeng Feng
- Brain Injury Center, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- *Correspondence: Junfeng Feng, ; Dingchang Zheng,
| | - Dingchang Zheng
- Research Centre for Intelligent Healthcare, Coventry University, Coventry, United Kingdom
- *Correspondence: Junfeng Feng, ; Dingchang Zheng,
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11
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Sleep cycle-dependent vascular dynamics in male mice and the predicted effects on perivascular cerebrospinal fluid flow and solute transport. Nat Commun 2023; 14:953. [PMID: 36806170 PMCID: PMC9941497 DOI: 10.1038/s41467-023-36643-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Accepted: 02/01/2023] [Indexed: 02/22/2023] Open
Abstract
Perivascular spaces are important highways for fluid and solute transport in the brain enabling efficient waste clearance during sleep. However, the underlying mechanisms augmenting perivascular flow in sleep are unknown. Using two-photon imaging of naturally sleeping male mice we demonstrate sleep cycle-dependent vascular dynamics of pial arteries and penetrating arterioles: slow, large-amplitude oscillations in NREM sleep, a vasodilation in REM sleep, and a vasoconstriction upon awakening at the end of a sleep cycle and microarousals in NREM and intermediate sleep. These vascular dynamics are mirrored by changes in the size of the perivascular spaces of the penetrating arterioles: slow fluctuations in NREM sleep, reduction in REM sleep and an enlargement upon awakening after REM sleep and during microarousals in NREM and intermediate sleep. By biomechanical modeling we demonstrate that these sleep cycle-dependent perivascular dynamics likely enhance fluid flow and solute transport in perivascular spaces to levels comparable to cardiac pulsation-driven oscillations.
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12
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van der Thiel MM, Backes WH, Ramakers IHGB, Jansen JFA. Novel developments in non-contrast enhanced MRI of the perivascular clearance system: What are the possibilities for Alzheimer's disease research? Neurosci Biobehav Rev 2023; 144:104999. [PMID: 36529311 DOI: 10.1016/j.neubiorev.2022.104999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 11/21/2022] [Accepted: 12/10/2022] [Indexed: 12/23/2022]
Abstract
The cerebral waste clearance system (i.e, glymphatic or intramural periarterial drainage) works through a network of perivascular spaces (PVS). Dysfunction of this system likely contributes to aggregation of Amyloid-β and subsequent toxic plaques in Alzheimer's disease (AD). A promising, non-invasive technique to study this system is MRI, though applications in dementia are still scarce. This review focusses on recent non-contrast enhanced (non-CE) MRI techniques which determine and visualise physiological aspects of the clearance system at multiple levels, i.e., cerebrospinal fluid flow, PVS-flow and interstitial fluid movement. Furthermore, various MRI studies focussing on aspects of the clearance system which are relevant to AD are discussed, such as studies on ageing, sleep alterations, and cognitive decline. Additionally, the complementary function of non-CE to CE methods is elaborated upon. We conclude that non-CE studies have great potential to determine which parts of the waste clearance system are affected by AD and in which stages of cognitive impairment dysfunction of this system occurs, which could allow future clinical trials to target these specific mechanisms.
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Affiliation(s)
- Merel M van der Thiel
- Department of Radiology & Nuclear Medicine, Maastricht University Medical Center, Maastricht, the Netherlands; Department of Psychiatry &Neuropsychology, Maastricht University, Maastricht, the Netherlands; School for Mental Health & Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Walter H Backes
- Department of Radiology & Nuclear Medicine, Maastricht University Medical Center, Maastricht, the Netherlands; School for Mental Health & Neuroscience, Maastricht University, Maastricht, the Netherlands; School for Cardiovascular Disease, Maastricht University, Maastricht, the Netherlands
| | - Inez H G B Ramakers
- Department of Psychiatry &Neuropsychology, Maastricht University, Maastricht, the Netherlands; School for Mental Health & Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Jacobus F A Jansen
- Department of Radiology & Nuclear Medicine, Maastricht University Medical Center, Maastricht, the Netherlands; School for Mental Health & Neuroscience, Maastricht University, Maastricht, the Netherlands; Department of Electrical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands.
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13
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Semyachkina-Glushkovskaya OV, Postnov DE, Khorovodov AP, Navolokin NA, Kurthz JHG. Lymphatic Drainage System of the Brain: a New Player in Neuroscience. J EVOL BIOCHEM PHYS+ 2023. [DOI: 10.1134/s0022093023010015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
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14
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Liu G, Ladrón-de-Guevara A, Izhiman Y, Nedergaard M, Du T. Measurements of cerebrospinal fluid production: a review of the limitations and advantages of current methodologies. Fluids Barriers CNS 2022; 19:101. [PMID: 36522656 PMCID: PMC9753305 DOI: 10.1186/s12987-022-00382-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 10/13/2022] [Indexed: 12/23/2022] Open
Abstract
Cerebrospinal fluid (CSF) is an essential and critical component of the central nervous system (CNS). According to the concept of the "third circulation" originally proposed by Cushing, CSF is mainly produced by the choroid plexus and subsequently leaves the cerebral ventricles via the foramen of Magendie and Luschka. CSF then fills the subarachnoid space from whence it disperses to all parts of the CNS, including the forebrain and spinal cord. CSF provides buoyancy to the submerged brain, thus protecting it against mechanical injury. CSF is also transported via the glymphatic pathway to reach deep interstitial brain regions along perivascular channels; this CSF clearance pathway promotes transport of energy metabolites and signaling molecules, and the clearance of metabolic waste. In particular, CSF is now intensively studied as a carrier for the removal of proteins implicated in neurodegeneration, such as amyloid-β and tau. Despite this key function of CSF, there is little information about its production rate, the factors controlling CSF production, and the impact of diseases on CSF flux. Therefore, we consider it to be a matter of paramount importance to quantify better the rate of CSF production, thereby obtaining a better understanding of CSF dynamics. To this end, we now review the existing methods developed to measure CSF production, including invasive, noninvasive, direct, and indirect methods, and MRI-based techniques. Depending on the methodology, estimates of CSF production rates in a given species can extend over a ten-fold range. Throughout this review, we interrogate the technical details of CSF measurement methods and discuss the consequences of minor experimental modifications on estimates of production rate. Our aim is to highlight the gaps in our knowledge and inspire the development of more accurate, reproducible, and less invasive techniques for quantitation of CSF production.
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Affiliation(s)
- Guojun Liu
- Department of Neurosurgery, The Fourth Affiliated Hospital of China Medical University, Shenyang, 110032, China
- School of Pharmacy, China Medical University, Shenyang, 110122, China
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark
- Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Antonio Ladrón-de-Guevara
- Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Yara Izhiman
- Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark.
- Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY, 14642, USA.
| | - Ting Du
- School of Pharmacy, China Medical University, Shenyang, 110122, China.
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark.
- Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY, 14642, USA.
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15
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Young BA, Cramberg M. The Influence of Movement on the Cerebrospinal Fluid Pressure of the American Alligator ( Alligator mississippiensis). BIOLOGY 2022; 11:biology11121702. [PMID: 36552212 PMCID: PMC9774609 DOI: 10.3390/biology11121702] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 11/08/2022] [Accepted: 11/23/2022] [Indexed: 11/27/2022]
Abstract
This study was undertaken to document how the cerebrospinal fluid (CSF) pressure varied during movements and physiological activities. Using surgically implanted pressure catheters; the CSF pressure was recorded from sub-adult American alligators (Alligator mississippiensis) under anesthesia and post-recovery. Pressures were recorded during physiological activities (the cardiac cycle; passive and active ventilation); manual manipulation of the anesthetized animals (foot sweeps; tail oscillations; and body bends); as well as voluntary movements post-recovery (changes in body tone; defensive strikes; and locomotion). The CSF pulsations associated with the cardiac cycle had the lowest mean amplitude (3.7 mm Hg); during active ventilation and defensive strikes; the alligators routinely generated CSF pressure spikes in excess of 100 mm Hg. The recorded CSF pressures appear to be caused by a variety of mechanisms including vascular pressure; fluid inertia; and possible physical displacement of the spinal cord. The results of the study suggest that any model of CSF dynamics or perfusion should incorporate the episodic high-pressure CSF pulsations associated with movement.
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16
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Vandenbulcke S, De Pauw T, Dewaele F, Degroote J, Segers P. Computational fluid dynamics model to predict the dynamical behavior of the cerebrospinal fluid through implementation of physiological boundary conditions. Front Bioeng Biotechnol 2022; 10:1040517. [PMID: 36483773 PMCID: PMC9722737 DOI: 10.3389/fbioe.2022.1040517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 11/11/2022] [Indexed: 10/22/2023] Open
Abstract
Cerebrospinal fluid (CSF) dynamics play an important role in maintaining a stable central nervous system environment and are influenced by different physiological processes. Multiple studies have investigated these processes but the impact of each of them on CSF flow is not well understood. A deeper insight into the CSF dynamics and the processes impacting them is crucial to better understand neurological disorders such as hydrocephalus, Chiari malformation, and intracranial hypertension. This study presents a 3D computational fluid dynamics (CFD) model which incorporates physiological processes as boundary conditions. CSF production and pulsatile arterial and venous volume changes are implemented as inlet boundary conditions. At the outlets, 2-element windkessel models are imposed to simulate CSF compliance and absorption. The total compliance is first tuned using a 0D model to obtain physiological pressure pulsations. Then, simulation results are compared with in vivo flow measurements in the spinal subarachnoid space (SAS) and cerebral aqueduct, and intracranial pressure values reported in the literature. Finally, the impact of the distribution of and total compliance on CSF pressures and velocities is evaluated. Without respiration effects, compliance of 0.17 ml/mmHg yielded pressure pulsations with an amplitude of 5 mmHg and an average value within the physiological range of 7-15 mmHg. Also, model flow rates were found to be in good agreement with reported values. However, when adding respiration effects, similar pressure amplitudes required an increase of compliance value to 0.51 ml/mmHg, which is within the range of 0.4-1.2 ml/mmHg measured in vivo. Moreover, altering the distribution of compliance over the four different outlets impacted the local flow, including the flow through the foramen magnum. The contribution of compliance to each outlet was directly proportional to the outflow at that outlet. Meanwhile, the value of total compliance impacted intracranial pressure. In conclusion, a computational model of the CSF has been developed that can simulate CSF pressures and velocities by incorporating boundary conditions based on physiological processes. By tuning these boundary conditions, we were able to obtain CSF pressures and flows within the physiological range.
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Affiliation(s)
- Sarah Vandenbulcke
- Institute of Biomedical Engineering and Technology (IBiTech-bioMMeda), Department of Electronics and Information Systems, Ghent University, Ghent, Belgium
| | - Tim De Pauw
- Department of Neurosurgery, Ghent University Hospital, Ghent, Belgium
| | - Frank Dewaele
- Department of Neurosurgery, Ghent University Hospital, Ghent, Belgium
| | - Joris Degroote
- Department of Electromechanical Systems and Metal Engineering, Ghent University, Ghent, Belgium
| | - Patrick Segers
- Institute of Biomedical Engineering and Technology (IBiTech-bioMMeda), Department of Electronics and Information Systems, Ghent University, Ghent, Belgium
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17
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Causemann M, Vinje V, Rognes ME. Human intracranial pulsatility during the cardiac cycle: a computational modelling framework. Fluids Barriers CNS 2022; 19:84. [PMID: 36320038 PMCID: PMC9623946 DOI: 10.1186/s12987-022-00376-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 09/28/2022] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND Today's availability of medical imaging and computational resources set the scene for high-fidelity computational modelling of brain biomechanics. The brain and its environment feature a dynamic and complex interplay between the tissue, blood, cerebrospinal fluid (CSF) and interstitial fluid (ISF). Here, we design a computational platform for modelling and simulation of intracranial dynamics, and assess the models' validity in terms of clinically relevant indicators of brain pulsatility. Focusing on the dynamic interaction between tissue motion and ISF/CSF flow, we treat the pulsatile cerebral blood flow as a prescribed input of the model. METHODS We develop finite element models of cardiac-induced fully coupled pulsatile CSF flow and tissue motion in the human brain environment. The three-dimensional model geometry is derived from magnetic resonance images (MRI) and features a high level of detail including the brain tissue, the ventricular system, and the cranial subarachnoid space (SAS). We model the brain parenchyma at the organ-scale as an elastic medium permeated by an extracellular fluid network and describe flow of CSF in the SAS and ventricles as viscous fluid movement. Representing vascular expansion during the cardiac cycle, a prescribed pulsatile net blood flow distributed over the brain parenchyma acts as the driver of motion. Additionally, we investigate the effect of model variations on a set of clinically relevant quantities of interest. RESULTS Our model predicts a complex interplay between the CSF-filled spaces and poroelastic parenchyma in terms of ICP, CSF flow, and parenchymal displacements. Variations in the ICP are dominated by their temporal amplitude, but with small spatial variations in both the CSF-filled spaces and the parenchyma. Induced by ICP differences, we find substantial ventricular and cranial-spinal CSF flow, some flow in the cranial SAS, and small pulsatile ISF velocities in the brain parenchyma. Moreover, the model predicts a funnel-shaped deformation of parenchymal tissue in dorsal direction at the beginning of the cardiac cycle. CONCLUSIONS Our model accurately depicts the complex interplay of ICP, CSF flow and brain tissue movement and is well-aligned with clinical observations. It offers a qualitative and quantitative platform for detailed investigation of coupled intracranial dynamics and interplay, both under physiological and pathophysiological conditions.
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Affiliation(s)
- Marius Causemann
- grid.419255.e0000 0004 4649 0885Department of Numerical Analysis and Scientific Computing, Simula Research Laboratory, Kristian Augusts gate 23, 0164 Oslo, Norway
| | - Vegard Vinje
- grid.419255.e0000 0004 4649 0885Department of Numerical Analysis and Scientific Computing, Simula Research Laboratory, Kristian Augusts gate 23, 0164 Oslo, Norway
| | - Marie E. Rognes
- grid.419255.e0000 0004 4649 0885Department of Numerical Analysis and Scientific Computing, Simula Research Laboratory, Kristian Augusts gate 23, 0164 Oslo, Norway ,grid.7914.b0000 0004 1936 7443Department of Mathematics, University of Bergen, P. O. Box 7803, 5020 Bergen, Norway
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18
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Hornkjøl M, Valnes LM, Ringstad G, Rognes ME, Eide PK, Mardal KA, Vinje V. CSF circulation and dispersion yield rapid clearance from intracranial compartments. Front Bioeng Biotechnol 2022; 10:932469. [PMID: 36172015 PMCID: PMC9510842 DOI: 10.3389/fbioe.2022.932469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Accepted: 08/17/2022] [Indexed: 11/13/2022] Open
Abstract
In this paper, we used a computational model to estimate the clearance of a tracer driven by the circulation of cerebrospinal fluid (CSF) produced in the choroid plexus (CP) located within the lateral ventricles. CSF was assumed to exit the subarachnoid space (SAS) via different outflow routes such as the parasagittal dura, cribriform plate, and/or meningeal lymphatics. We also modelled a reverse case where fluid was produced within the spinal canal and absorbed in the choroid plexus in line with observations on certain iNPH patients. No directional interstitial fluid flow was assumed within the brain parenchyma. Tracers were injected into the foramen magnum. The models demonstrate that convection in the subarachnoid space yields rapid clearance from both the SAS and the brain interstitial fluid and can speed up intracranial clearance from years, as would be the case for purely diffusive transport, to days.
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Affiliation(s)
- Martin Hornkjøl
- Department of Mathematics, University of Oslo, Blindern, Norway
- *Correspondence: Martin Hornkjøl,
| | - Lars Magnus Valnes
- Department of Neurosurgery, Oslo University Hospital–Rikshospitalet, Oslo, Norway
| | - Geir Ringstad
- Department of Radiology, Oslo University Hospital, Oslo, Norway
- Department of Geriatrics and Internal Medicine, Sorlandet Hospital, Arendal, Norway
| | - Marie E. Rognes
- Department of Numerical Analysis and Scientific Computing, Simula Research Laboratory, Oslo, Norway
- Department of Mathematics, University of Bergen, Bergen, Norway
| | - Per-Kristian Eide
- Department of Neurosurgery, Oslo University Hospital–Rikshospitalet, Oslo, Norway
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Kent-André Mardal
- Department of Mathematics, University of Oslo, Blindern, Norway
- Department of Numerical Analysis and Scientific Computing, Simula Research Laboratory, Oslo, Norway
| | - Vegard Vinje
- Department of Numerical Analysis and Scientific Computing, Simula Research Laboratory, Oslo, Norway
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19
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Gutiérrez-Montes C, Coenen W, Vidorreta M, Sincomb S, Martínez-Bazán C, Sánchez AL, Haughton V. Effect of Normal Breathing on the Movement of CSF in the Spinal Subarachnoid Space. AJNR Am J Neuroradiol 2022; 43:1369-1374. [PMID: 35981761 PMCID: PMC9451622 DOI: 10.3174/ajnr.a7603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 06/24/2022] [Indexed: 01/26/2023]
Abstract
BACKGROUND AND PURPOSE Forced respirations reportedly have an effect on CSF movement in the spinal canal. We studied respiratory-related CSF motion during normal respiration. MATERIALS AND METHODS Six healthy subjects breathed at their normal rate with a visual guide to ensure an unchanging rhythm. Respiratory-gated phase-contrast MR flow images were acquired at 5 selected axial planes along the spine. At each spinal level, we computed the flow rate voxelwise in the spinal canal, together with the associated stroke volume. From these data, we computed the periodic volume changes of spinal segments. A phantom was used to quantify the effect of respiration-related magnetic susceptibility changes on the velocity data measured. RESULTS At each level, CSF moved cephalad during inhalation and caudad during expiration. While the general pattern of fluid movement was the same in the 6 subjects, the flow rates, stroke volumes, and spine segment volume changes varied among subjects. Peak flow rates ranged from 0.60 to 1.59 mL/s in the cervical region, 0.46 to 3.17 mL/s in the thoracic region, and 0.75 to 3.64 mL/s in the lumbar region. The differences in flow rates along the canal yielded cyclic volume variations of spine segments that were largest in the lumbar spine, ranging from 0.76 to 3.07 mL among subjects. In the phantom study, flow velocities oscillated periodically during the respiratory cycle by up to 0.02 cm/s or 0.5%. CONCLUSIONS Respiratory-gated measurements of the CSF motion in the spinal canal showed cyclic oscillatory movements of spinal fluid correlated to the breathing pattern.
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Affiliation(s)
- C Gutiérrez-Montes
- From the Department of Mechanical and Mining Engineering (C.G.-M.), University of Jaén, Jaén, Andalucía, Spain
| | - W Coenen
- Grupo de Mecánica de Fluidos, Departamento de Ingeniería Térmica y de Fluidos (W.C.), Universidad Carlos III de Madrid, Madrid, Spain
| | | | - S Sincomb
- Department of Mechanical and Aerospace Engineering (S.S., A.L.S.), University of California San Diego, San Diego, California
| | - C Martínez-Bazán
- Department of Structural Mechanics and Hydraulic Engineering (C.M.-B.), University of Granada, Granada, Spain
| | - A L Sánchez
- Department of Mechanical and Aerospace Engineering (S.S., A.L.S.), University of California San Diego, San Diego, California
| | - V Haughton
- Department of Radiology (V.H.), School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin
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20
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Abstract
We review theoretical and numerical models of the glymphatic system, which circulates cerebrospinal fluid and interstitial fluid around the brain, facilitating solute transport. Models enable hypothesis development and predictions of transport, with clinical applications including drug delivery, stroke, cardiac arrest, and neurodegenerative disorders like Alzheimer’s disease. We sort existing models into broad categories by anatomical function: Perivascular flow, transport in brain parenchyma, interfaces to perivascular spaces, efflux routes, and links to neuronal activity. Needs and opportunities for future work are highlighted wherever possible; new models, expanded models, and novel experiments to inform models could all have tremendous value for advancing the field.
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21
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Sheng J, Li Q, Liu T, Wang X. Cerebrospinal fluid dynamics along the optic nerve. Front Neurol 2022; 13:931523. [PMID: 36046631 PMCID: PMC9420993 DOI: 10.3389/fneur.2022.931523] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 07/21/2022] [Indexed: 11/23/2022] Open
Abstract
The cerebrospinal fluid (CSF) plays an important role in delivering nutrients and eliminating the metabolic wastes of the central nervous system. An interrupted CSF flow could cause disorders of the brain and eyes such as Alzheimer's disease and glaucoma. This review provides an overview of the anatomy and flow pathways of the CSF system with an emphasis on the optic nerve. Imaging technologies used for visualizing the CSF dynamics and the anatomic structures associated with CSF circulation have been highlighted. Recent advances in the use of computational models to predict CSF flow patterns have been introduced. Open questions and potential mechanisms underlying CSF circulation at the optic nerves have also been discussed.
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Affiliation(s)
- Jinqiao Sheng
- Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
- School of General Engineering, Beihang University, Beijing, China
| | - Qi Li
- Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Tingting Liu
- Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Xiaofei Wang
- Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
- *Correspondence: Xiaofei Wang
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22
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Assessing pulsatile waveforms of paravascular cerebrospinal fluid dynamics using dynamic diffusion-weighted imaging (dDWI). Neuroimage 2022; 260:119464. [PMID: 35835339 PMCID: PMC9434732 DOI: 10.1016/j.neuroimage.2022.119464] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 07/08/2022] [Accepted: 07/10/2022] [Indexed: 11/25/2022] Open
Abstract
Cerebrospinal fluid (CSF) in the paravascular spaces of the surface arteries (sPVS) is a vital pathway in brain waste clearance. Arterial pulsations may be the driving force of the paravascular flow, but its pulsatile pattern remains poorly characterized, and no clinically practical method for measuring its dynamics in the human brain is available. In this work, we introduce an imaging and quantification framework for in-vivo non-invasive assessment of pulsatile fluid dynamics in the sPVS. It used dynamic Diffusion-Weighted Imaging (dDWI) at a lower b-values of 150s/mm2 and retrospective gating to detect the slow flow of CSF while suppressing the fast flow of adjacent arterial blood. The waveform of CSF flow over a cardiac cycle was revealed by synchronizing the measurements with the heartbeat. A data-driven approach was developed to identify sPVS and allow automatic quantification of the whole-brain fluid waveforms. We applied dDWI to twenty-five participants aged 18–82 y/o. Results demonstrated that the fluid waveforms across the brain showed an explicit cardiac-cycle dependency, in good agreement with the vascular pumping hypothesis. Furthermore, the shape of the CSF waveforms closely resembled the pressure waveforms of the artery wall, suggesting that CSF dynamics is tightly related to artery wall mechanics. Finally, the CSF waveforms in aging participants revealed a strong age effect, with a significantly wider systolic peak observed in the older relative to younger participants. The peak widening may be associated with compromised vascular compliance and vessel wall stiffening in the older brain. Overall, the results demonstrate the feasibility, reproducibility, and sensitivity of dDWI for detecting sPVS fluid dynamics of the human brain. Our preliminary data suggest age-related alterations of the paravascular pumping. With an acquisition time of under six minutes, dDWI can be readily applied to study fluid dynamics in normal physiological conditions and cerebrovascular/neurodegenerative diseases.
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23
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Young BA, Cramberg MJ. Treadmill locomotion in the American alligator (Alligator mississippiensis) produces dynamic changes in intracranial cerebrospinal fluid pressure. Sci Rep 2022; 12:11826. [PMID: 35821242 PMCID: PMC9276781 DOI: 10.1038/s41598-022-15918-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 07/01/2022] [Indexed: 11/09/2022] Open
Abstract
To examine the influence of movement on cerebrospinal fluid (CSF) dynamics, intracranial subdural pressure recordings were taken from sub-adult alligators (Alligator mississippiensis) locomoting on a treadmill. Pressure recordings documenting the cardiac, ventilatory, and barostatic influences on the CSF were in good agreement with previous studies. During locomotion the CSF exhibits sinusoidal patterns of pressure change that spanned a mean amplitude of 56 mm Hg, some 16 × the amplitude of the cardiac-linked pulsations. These sinusoidal CSF pulsations were closely linked to the locomotor kinematics, particularly the lateral oscillations of the alligator's head. Data recorded from the freely moving alligators suggest that fluid inertia, body cavity pressures, and likely other factors all influence the CSF pressure. The clear relationship between movement and CSF pressure described in this study suggests that the paucity of studies examining human CSF dynamics during movement should be addressed.
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Affiliation(s)
- Bruce A Young
- Department of Anatomy, Kirksville College of Osteopathic Medicine, A.T. Still University, Kirksville, MO, 63501, USA.
| | - Michael J Cramberg
- Department of Anatomy, Kirksville College of Osteopathic Medicine, A.T. Still University, Kirksville, MO, 63501, USA
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24
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Yildiz S, Grinstead J, Hildebrand A, Oshinski J, Rooney WD, Lim MM, Oken B. Immediate impact of yogic breathing on pulsatile cerebrospinal fluid dynamics. Sci Rep 2022; 12:10894. [PMID: 35764793 PMCID: PMC9240010 DOI: 10.1038/s41598-022-15034-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 06/16/2022] [Indexed: 01/10/2023] Open
Abstract
Cerebrospinal fluid (CSF), a clear fluid bathing the central nervous system (CNS), undergoes pulsatile movements. Together with interstitial fluid, CSF plays a critical role for the removal of waste products from the brain, and maintenance of the CNS health. As such, understanding the mechanisms driving CSF movement is of high scientific and clinical impact. Since pulsatile CSF dynamics is sensitive and synchronous to respiratory movements, we are interested in identifying potential integrative therapies such as yogic breathing to regulate CSF dynamics, which has not been reported before. Here, we investigated the pre-intervention baseline data from our ongoing randomized controlled trial, and examined the impact of four yogic breathing patterns: (i) slow, (ii) deep abdominal, (iii) deep diaphragmatic, and (iv) deep chest breathing with the last three together forming a yogic breathing called three-part breath. We utilized our previously established non-invasive real-time phase contrast magnetic resonance imaging approach using a 3T MRI instrument, computed and tested differences in single voxel CSF velocities (instantaneous, respiratory, cardiac 1st and 2nd harmonics) at the level of foramen magnum during spontaneous versus yogic breathing. In examinations of 18 healthy participants (eight females, ten males; mean age 34.9 ± 14 (SD) years; age range: 18-61 years), we observed immediate increase in cranially-directed velocities of instantaneous-CSF 16-28% and respiratory-CSF 60-118% during four breathing patterns compared to spontaneous breathing, with the greatest changes during deep abdominal breathing (28%, p = 0.0008, and 118%, p = 0.0001, respectively). Cardiac pulsation was the primary source of pulsatile CSF motion except during deep abdominal breathing, when there was a comparable contribution of respiratory and cardiac 1st harmonic power [0.59 ± 0.78], suggesting respiration can be the primary regulator of CSF depending on the individual differences in breathing techniques. Further work is needed to investigate the impact of sustained training yogic breathing on pulsatile CSF dynamics for CNS health.
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Affiliation(s)
- Selda Yildiz
- Department of Neurology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239, USA.
| | - John Grinstead
- Siemens Medical Solutions USA, Inc, Portland, OR, 97239, USA
| | - Andrea Hildebrand
- Biostatistics and Design Program, Oregon Health & Science University, Portland, OR, 97239, USA
| | - John Oshinski
- Radiology & Imaging Sciences and Biomedical Engineering, Emory School of Medicine, Emory University, Atlanta, GA, 30322, USA
| | - William D Rooney
- Department of Neurology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239, USA
- Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR, 97239, USA
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, 97239, USA
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, 97239, USA
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Miranda M Lim
- Department of Neurology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239, USA
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, 97239, USA
- VA Portland Health Care System, Portland, OR, 97239, USA
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Oregon Health & Science University, Portland, OR, 97239, USA
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Barry Oken
- Department of Neurology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239, USA
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, 97239, USA
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25
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Faryami A, Menkara A, Viar D, Harris CA. Testing and validation of reciprocating positive displacement pump for benchtop pulsating flow model of cerebrospinal fluid production and other physiologic systems. PLoS One 2022; 17:e0262372. [PMID: 35550626 PMCID: PMC9098063 DOI: 10.1371/journal.pone.0262372] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 04/15/2022] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND The flow of physiologic fluids through organs and organs systems is an integral component of their function. The complex fluid dynamics in many organ systems are still not completely understood, and in-vivo measurements of flow rates and pressure provide a testament to the complexity of each flow system. Variability in in-vivo measurements and the lack of control over flow characteristics leave a lot to be desired for testing and evaluation of current modes of treatments as well as future innovations. In-vitro models are particularly ideal for studying neurological conditions such as hydrocephalus due to their complex pathophysiology and interactions with therapeutic measures. The following aims to present the reciprocating positive displacement pump, capable of inducing pulsating flow of a defined volume at a controlled beat rate and amplitude. While the other fluidic applications of the pump are currently under investigation, this study was focused on simulating the pulsating cerebrospinal fluid production across profiles with varying parameters. METHODS Pumps were manufactured using 3D printed and injection molded parts. The pumps were powered by an Arduino-based board and proprietary software that controls the linear motion of the pumps to achieve the specified output rate at the desired pulsation rate and amplitude. A range of 0.01 [Formula: see text] to 0.7 [Formula: see text] was tested to evaluate the versatility of the pumps. The accuracy and precision of the pumps' output were evaluated by obtaining a total of 150 one-minute weight measurements of degassed deionized water per output rate across 15 pump channels. In addition, nine experiments were performed to evaluate the pumps' control over pulsation rate and amplitude. RESULTS Volumetric analysis of a total of 1200 readings determined that the pumps achieved the target output volume rate with a mean absolute error of -0.001034283 [Formula: see text] across the specified domain. It was also determined that the pumps can maintain pulsatile flow at a user-specified beat rate and amplitude. CONCLUSION The validation of this reciprocating positive displacement pump system allows for the future validation of novel designs to components used to treat hydrocephalus and other physiologic models involving pulsatile flow. Based on the promising results of these experiments at simulating pulsatile CSF flow, a benchtop model of human CSF production and distribution could be achieved through the incorporation of a chamber system and a compliance component.
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Affiliation(s)
- Ahmad Faryami
- Department of Biomedical Engineering, Wayne State University, Detroit, MI, United States of America
| | - Adam Menkara
- Department of Biomedical Engineering, Wayne State University, Detroit, MI, United States of America
| | - Daniel Viar
- Department of Computer Science and Engineering, University of Toledo, Toledo, Ohio, United States of America
| | - Carolyn A. Harris
- Wayne State University Dept. of Chemical Engineering and Materials Science, Detroit, MI, United States of America
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26
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Measurement of CSF pulsation from EPI-based human fMRI. Neuroimage 2022; 257:119293. [PMID: 35551990 DOI: 10.1016/j.neuroimage.2022.119293] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 05/01/2022] [Accepted: 05/08/2022] [Indexed: 11/22/2022] Open
Abstract
It is recently discovered that the glymphatic system and meningeal lymphatic system are the primary routes for the clearance of brain waste products. The CSF flow is part of these systems, facilitating the clearance procedure. Nonetheless, the relationship between CSF flow and brain functional activity has been underexplored. To investigate CSF dynamics and functional brain activity simultaneously, recent studies have proposed a CSF inflow index measured on edge slices (CSFedge) of echo-planar imaging (EPI) based functional magnetic resonance imaging (fMRI), however, it lacks the quantitative aspect of the CSF pulsation. We proposed a new method for quantifying CSF pulsation (CSFpulse) based on an interslice CSF pulsation model in the 4th ventricle of EPI-based fMRI. The proposed CSFpulse successfully detected the higher CSF flow during the resting state than the typical task states (visual and motor) (p<.05), which is consistent with previous studies based on phase contrast (PC) MRI and CSF volume MRI, while it was not detected in CSFedge based indices or baseline CSF signals in various regions of interest (ROIs). Moreover, CSFpulse demonstrated dynamic functional changes in CSF pulsation: it decreased during the activation-on blocks while it increased during the activation-off blocks. CSFpulse significantly correlated with stroke volume measured using PC MRI, a standard method for CSF pulsation quantification, under the same functional state, while CSFedge based indices or CSF ROIs showed no correlation with the PC MRI stroke volume. Lastly, the correlation of CSFpulse with global BOLD was weaker than that of CSFedge, suggesting that CSFpulse may reflect distinct CSF physiological information that is less affected by global BOLD effects. Based on these results, the proposed CSFpulse provides CSF pulsatility information more accurately in a quantitative manner than CSFedge based indices from the recent CSF studies or the conventional ROI-based analysis. In addition to the high correlation with PC MRI, CSFpulse is much faster than PC MRI and provides information of functional brain activations simultaneously, advantageous over PC MRI or CSF volume MRI. Accordingly, the suggested CSFpulse can be used for investigating intra-subject functional changes in BOLD and CSF pulsation simultaneously and inter-subject CSF pulsation variations based on conventional EPI-based fMRI, which warrants further investigation.
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Morphometrics of the Spinal Cord and Surrounding Structures in Alligator mississippiensis. BIOLOGY 2022; 11:biology11040514. [PMID: 35453713 PMCID: PMC9024830 DOI: 10.3390/biology11040514] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 03/22/2022] [Accepted: 03/24/2022] [Indexed: 02/04/2023]
Abstract
Simple Summary Morphometric analysis of the spinal cord and surrounding tissue of the American alligator (Alligator mississippiensis) reveals that there are four significantly discrete regions; cervical, thoracic, lumbar, and caudal. Crocodylians, unlike mammals, have a caudal spinal cord that extends throughout the length of their tail (which accounts for roughly 50% of their total body length). Alligator mississippiensis has one of the largest ranges of body sizes among terrestrial vertebrates, this study documents how the different spinal structures change with increasing body size. Though most of the structures exhibit slightly positive allometry, a few exhibit slightly negative allometry; these differences mean that there are significant relational changes as hatchlings grow into large adults. This study provides the first documentation that A. mississippiensis has an expansive subdural space, a lumbar cistern, at the pelvis. Abstract Understanding the fluid dynamics of the cerebrospinal fluid requires a quantitative description of the spaces in which it flows, including the spinal cord and surrounding meninges. The morphometrics of the spinal cord and surrounding tissues were studied in specimens of the American alligator (Alligator mississippiensis) ranging from hatchlings through adults. Within any size class of alligators (i.e., hatchlings), along the axial length there are significant differences in the size of the spinal cord, meninges, and vertebral canal; these differences can be used to define discrete cervical, thoracic, lumbar and caudal regions. When compared across the range of body sizes in Alligator, every structure in each spinal region had a distinctive growth rate; thus, the physical arrangements between the structures changed as the alligator grew. The combination of regional differentiation and differential growth rates was particularly apparent in the lumbar meninges where a unique form of lumbar cistern could be identified and shown to decrease in relative size as the alligator ages. This analysis of the spinal cord and surrounding tissues was undertaken to develop a data set that could be used for computational flow dynamics of the crocodilian cerebrospinal fluid, and also to assist in the analysis of fossil archosaurs.
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Kollmeier JM, Gürbüz-Reiss L, Sahoo P, Badura S, Ellebracht B, Keck M, Gärtner J, Ludwig HC, Frahm J, Dreha-Kulaczewski S. Deep breathing couples CSF and venous flow dynamics. Sci Rep 2022; 12:2568. [PMID: 35173200 PMCID: PMC8850447 DOI: 10.1038/s41598-022-06361-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 01/24/2022] [Indexed: 11/30/2022] Open
Abstract
Venous system pathologies have increasingly been linked to clinically relevant disorders of CSF circulation whereas the exact coupling mechanisms still remain unknown. In this work, flow dynamics of both systems were studied using real-time phase-contrast flow MRI in 16 healthy subjects during normal and forced breathing. Flow evaluations in the aqueduct, at cervical level C3 and lumbar level L3 for both the CSF and venous fluid systems reveal temporal modulations by forced respiration. During normal breathing cardiac-related flow modulations prevailed, while forced breathing shifted the dominant frequency of both CSF and venous flow spectra towards the respiratory component and prompted a correlation between CSF and venous flow in the large vessels. The average of flow magnitude of CSF was increased during forced breathing at all spinal and intracranial positions. Venous flow in the large vessels of the upper body decreased and in the lower body increased during forced breathing. Deep respiration couples interdependent venous and brain fluid flow—most likely mediated by intrathoracic and intraabdominal pressure changes. Further insights into the driving forces of CSF and venous circulation and their correlation will facilitate our understanding how the venous system links to intracranial pressure regulation and of related forms of hydrocephalus.
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Affiliation(s)
- Jost M Kollmeier
- Biomedizinische NMR, Max-Planck-Institut für multidisziplinäre Naturwissenschaften, 37077, Göttingen, Germany
| | - Lukas Gürbüz-Reiss
- Division of Pediatric Neurology, Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Prativa Sahoo
- Division of Pediatric Neurology, Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Simon Badura
- Division of Pediatric Neurology, Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Ben Ellebracht
- Division of Pediatric Neurology, Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Mathilda Keck
- Division of Pediatric Neurology, Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Jutta Gärtner
- Division of Pediatric Neurology, Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Hans-Christoph Ludwig
- Division of Pediatric Neurosurgery, Department of Neurosurgery, University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Jens Frahm
- Biomedizinische NMR, Max-Planck-Institut für multidisziplinäre Naturwissenschaften, 37077, Göttingen, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site, Göttingen, Germany
| | - Steffi Dreha-Kulaczewski
- Division of Pediatric Neurology, Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, 37075, Göttingen, Germany.
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Stöcklein S, Brandlhuber M, Lause S, Pomschar A, Jahn K, Schniepp R, Alperin N, Ertl-Wagner B. Decreased Craniocervical CSF Flow in Patients with Normal Pressure Hydrocephalus: A Pilot Study. AJNR Am J Neuroradiol 2022; 43:230-237. [PMID: 34992125 PMCID: PMC8985674 DOI: 10.3174/ajnr.a7385] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 10/16/2021] [Indexed: 02/03/2023]
Abstract
BACKGROUND AND PURPOSE Normal pressure hydrocephalus is characterized by systolic peaks of raised intracranial pressure, possibly due to a reduced compliance of the spinal CSF spaces. This concept of a reduced spinal CSF buffer function may be reflected by a low cervical CSF outflow from the cranium. The aim of this study was to investigate craniospinal CSF flow rates by phase-contrast MR imaging in patients with normal pressure hydrocephalus. MATERIALS AND METHODS A total of 42 participants were included in this prospective study, consisting of 3 study groups: 1) 10 patients with normal pressure hydrocephalus (mean age, 74 [SD, 6] years, with proved normal pressure hydrocephalus according to current scientific criteria); 2) eighteen age-matched healthy controls (mean age, 71 [SD, 5] years); and 3) fourteen young healthy controls (mean age, 21 [SD, 2] years, for investigation of age-related effects). Axial phase-contrast MR imaging was performed, and the maximal systolic CSF and total arterial blood flow rates were measured at the level of the upper second cervical vertebra and compared among all study groups (2-sample unpaired t test). RESULTS The maximal systolic CSF flow rate was significantly decreased in patients with normal pressure hydrocephalus compared with age-matched and young healthy controls (53 [SD, 40] mL/m; 329 [SD, 175] mL/m; 472 [SD, 194] mL/m; each P < .01), whereas there were no significant differences with regard to maximal systolic arterial blood flow (1160 [SD, 404] mL/m; 1470 [SD, 381] mL/m; 1400 [SD, 254] mL/m; each P > .05). CONCLUSIONS The reduced maximal systolic craniospinal CSF flow rate in patients with normal pressure hydrocephalus may be reflective of a reduced compliance of the spinal CSF spaces and an ineffective spinal CSF buffer function. Systolic craniospinal CSF flow rates are an easily obtainable MR imaging-based measure that may support the diagnosis of normal pressure hydrocephalus.
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Affiliation(s)
| | | | - S.S. Lause
- Department of Dermatology (S.S.L.), Bethesda Hospital, Freudenberg, Germany
| | - A. Pomschar
- Radiological Office (A.P.), Centre for Radiology, Munich, Germany
| | - K. Jahn
- Neurology, and Friedrich-Baur-Institute (FBI) of the Department of Neurology (K.J.)
| | - R. Schniepp
- Neurology (R.S.), Ludwig-Maximilians-University Munich, Munich, Germany
| | - N. Alperin
- Department of Radiology (N.A.), University of Miami, Coral Gables, Florida
| | - B. Ertl-Wagner
- Department of Medical Imaging (B.E.-W.), The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
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30
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Picchioni D, Özbay PS, Mandelkow H, de Zwart JA, Wang Y, van Gelderen P, Duyn JH. Autonomic arousals contribute to brain fluid pulsations during sleep. Neuroimage 2022; 249:118888. [PMID: 35017126 DOI: 10.1016/j.neuroimage.2022.118888] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 11/15/2021] [Accepted: 01/05/2022] [Indexed: 12/28/2022] Open
Abstract
During sleep, slow waves of neuro-electrical activity engulf the human brain and aid in the consolidation of memories. Recent research suggests that these slow waves may also promote brain health by facilitating the removal of metabolic waste, possibly by orchestrating the pulsatile flow of cerebro-spinal fluid (CSF) through local neural control over vascular tone. To investigate the role of slow waves in the generation of CSF pulsations, we analyzed functional MRI data obtained across the full sleep-wake cycle and during a respiratory task during wakefulness. This revealed a novel generating mechanism that relies on the autonomic regulation of cerebral vascular tone without requiring slow electrocortical activity or even sleep. Therefore, the role of CSF pulsations in brain waste clearance may, in part, depend on proper autoregulatory control of cerebral blood flow.
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Affiliation(s)
- Dante Picchioni
- Advance MRI Section, Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health; Bethesda, Maryland
| | - Pinar S Özbay
- Advance MRI Section, Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health; Bethesda, Maryland
| | - Hendrik Mandelkow
- Advance MRI Section, Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health; Bethesda, Maryland
| | - Jacco A de Zwart
- Advance MRI Section, Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health; Bethesda, Maryland
| | - Yicun Wang
- Advance MRI Section, Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health; Bethesda, Maryland
| | - Peter van Gelderen
- Advance MRI Section, Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health; Bethesda, Maryland
| | - Jeff H Duyn
- Advance MRI Section, Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health; Bethesda, Maryland.
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31
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Sakakibara Y, Yatsushiro S, Konta N, Horie T, Kuroda K, Matsumae M. Respiratory-driven Cyclic Cerebrospinal Fluid Motion in the Intracranial Cavity on Magnetic Resonance Imaging: Insights into the Pathophysiology of Neurofluid Dysfunction. Neurol Med Chir (Tokyo) 2021; 61:711-720. [PMID: 34526448 PMCID: PMC8666299 DOI: 10.2176/nmc.oa.2021-0160] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Neurofluids, a recently developed term that refers to interstitial fluids in the parenchyma and cerebrospinal fluid (CSF) in the ventricle and subarachnoid space, play a role in draining waste products from the brain. Neurofluids have been implicated in pathological conditions such as Alzheimer’s disease and normal pressure hydrocephalus. Given that CSF moves faster in the CSF cavity than in the brain parenchyma, CSF motion can be detected by magnetic resonance imaging. CSF motion is synchronized to the heartbeat and respiratory cycle, but respiratory cycle-induced CSF motion has yet to be investigated in detail. Therefore, we analyzed CSF motion using dynamic improved motion-sensitized driven-equilibrium steady-state free precession-based analysis. We analyzed CSF motion linked to the respiratory cycle in four women and six men volunteers aged 23 to 38 years. We identified differences between free respiration and tasked respiratory cycle-associated CSF motion in the ventricles and subarachnoid space. Our results indicate that semi-quantitative analysis can be performed using the cranial site at which CSF motion is most prominent as a standard. Our findings may serve as a reference for elucidating the pathophysiology of diseases caused by abnormalities in neurofluids.
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Affiliation(s)
| | | | - Natsuo Konta
- Department of Radiology, Tokai University School of Medicine.,Graduate School of Radiological Technology, Gunma Prefectural College of Health Sciences
| | - Tomohiko Horie
- Department of Radiology, Tokai University School of Medicine
| | - Kagayaki Kuroda
- Department of Human and Information Sciences, School of Information Science and Technology, Tokai University
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32
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Sincomb SJ, Coenen W, Criado-Hidalgo E, Wei K, King K, Borzage M, Haughton V, Sánchez AL, Lasheras JC. Transmantle Pressure Computed from MR Imaging Measurements of Aqueduct Flow and Dimensions. AJNR Am J Neuroradiol 2021; 42:1815-1821. [PMID: 34385144 DOI: 10.3174/ajnr.a7246] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 05/27/2021] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Measuring transmantle pressure, the instantaneous pressure difference between the lateral ventricles and the cranial subarachnoid space, by intracranial pressure sensors has limitations. The aim of this study was to compute transmantle pressure noninvasively with a novel nondimensional fluid mechanics model in volunteers and to identify differences related to age and aqueductal dimensions. MATERIALS AND METHODS Brain MR images including cardiac-gated 2D phase-contrast MR imaging and fast-spoiled gradient recalled imaging were obtained in 77 volunteers ranging in age from 25-92 years of age. Transmantle pressure was computed during the cardiac cycle with a fluid mechanics model from the measured aqueductal flow rate, stroke volume, aqueductal length and cross-sectional area, and heart rate. Peak pressures during caudal and rostral aqueductal flow were tabulated. The computed transmantle pressure, aqueductal dimensions, and stroke volume were estimated, and the differences due to sex and age were calculated and tested for significance. RESULTS Peak transmantle pressure was calculated with the nondimensional averaged 14.4 (SD, 6.5) Pa during caudal flow and 6.9 (SD, 2.8) Pa during rostral flow. It did not differ significantly between men and women or correlate significantly with heart rate. Peak transmantle pressure increased with age and correlated with aqueductal dimensions and stroke volume. CONCLUSIONS The nondimensional fluid mechanics model for computing transmantle pressure detected changes in pressure related to age and aqueductal dimensions. This novel methodology can be easily used to investigate the clinical relevance of the transmantle pressure in normal pressure hydrocephalus, pediatric communicating hydrocephalus, and other CSF disorders.
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Affiliation(s)
- S J Sincomb
- From the Department of Mechanical and Aerospace Engineering (S.J.S., E.C.-H., A.L.S., J.C.L.), University of California San Diego, La Jolla, California
| | - W Coenen
- Departamento de Ingeniería Térmica y de Fluidos (W.C.), Grupo de Mecánica de Fluidos, Universidad Carlos III de Madrid, Leganés (Madrid), Spain
| | - E Criado-Hidalgo
- From the Department of Mechanical and Aerospace Engineering (S.J.S., E.C.-H., A.L.S., J.C.L.), University of California San Diego, La Jolla, California
| | - K Wei
- MRI Center (K.W.), Huntington Medical Research Institutes, Pasadena, California
| | - K King
- Barrow Neurological Institute (K.K.), Phoenix, Arizona
| | - M Borzage
- Fetal and Neonatal Institute (M.B.), Division of Neonatology, Children's Hospital Los Angeles, Los Angeles, California.,Department of Pediatrics (M.B.), Keck School of Medicine, University of Southern California, Los Angeles, California
| | - V Haughton
- Department of Radiology (V.H.), School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
| | - A L Sánchez
- From the Department of Mechanical and Aerospace Engineering (S.J.S., E.C.-H., A.L.S., J.C.L.), University of California San Diego, La Jolla, California
| | - J C Lasheras
- From the Department of Mechanical and Aerospace Engineering (S.J.S., E.C.-H., A.L.S., J.C.L.), University of California San Diego, La Jolla, California
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33
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Brain solute transport is more rapid in periarterial than perivenous spaces. Sci Rep 2021; 11:16085. [PMID: 34373476 PMCID: PMC8352970 DOI: 10.1038/s41598-021-95306-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 07/23/2021] [Indexed: 11/13/2022] Open
Abstract
Fluid flow in perivascular spaces is recognized as a key component underlying brain transport and clearance. An important open question is how and to what extent differences in vessel type or geometry affect perivascular fluid flow and transport. Using computational modelling in both idealized and image-based geometries, we study and compare fluid flow and solute transport in pial (surface) periarterial and perivenous spaces. Our findings demonstrate that differences in geometry between arterial and venous pial perivascular spaces (PVSs) lead to higher net CSF flow, more rapid tracer transport and earlier arrival times of injected tracers in periarterial spaces compared to perivenous spaces. These findings can explain the experimentally observed rapid appearance of tracers around arteries, and the delayed appearance around veins without the need of a circulation through the parenchyma, but rather by direct transport along the PVSs.
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34
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Martinac AD, Fletcher DF, Bilston LE. Phase offset between arterial pulsations and subarachnoid space pressure fluctuations are unlikely to drive periarterial cerebrospinal fluid flow. Biomech Model Mechanobiol 2021; 20:1751-1766. [PMID: 34275063 DOI: 10.1007/s10237-021-01474-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 06/02/2021] [Indexed: 11/24/2022]
Abstract
Circulation of fluid through the central nervous system maintains fluid homeostasis and is involved in solute clearance. The glymphatic system is hypothesised to facilitate waste clearance in the brain, with inflow via periarterial spaces, bulk flow through the parenchyma, and outflow via perivenous spaces. The driving force for this mechanism is unknown. Previous modelling in the spinal cord suggests that timing offsets between arterial and subarachnoid space pressure pulses can enable net inflow in perivascular spaces (PVS). This study adapted the spinal pulse offset mechanism to the brain and simulated movement of tracer particles used in experiments. Both bulk flow and diffusive movement of tracer were simulated. Intracranial pressure pulses were applied to one end of a 300-μm-long perivascular space combined with a moving arterial wall simulating arterial pulsations. The simulations indicate the pulse offset mechanism can enable net inflow via PVS; however, it is unknown whether the temporal offset required is physiologically realistic. Increasing the positive component of the ICP (intracranial pressure) pulse increased net flow. Tracer particles driven by bulk flow reached the outlet of the PVS with a net speed of ~ 16 μm/s when the permeability was two orders of magnitude higher than values in the literature. These particles were unable to penetrate into the parenchyma in the absence of diffusion. Dispersion dominated tracer movement in the parenchyma. Further research is required to reconcile discrepancies between these results, and both experimental and computational studies.
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Affiliation(s)
- Adam D Martinac
- Neuroscience Research Australia and Prince of Wales Clinical School, UNSW, Kensington, Australia.
| | - David F Fletcher
- School of Chemical and Biomolecular Engineering, The University of Sydney, Camperdown, Australia
| | - Lynne E Bilston
- Neuroscience Research Australia and Prince of Wales Clinical School, UNSW, Kensington, Australia
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35
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Slithering CSF: Cerebrospinal Fluid Dynamics in the Stationary and Moving Viper Boa, Candoia aspera. BIOLOGY 2021; 10:biology10070672. [PMID: 34356527 PMCID: PMC8301399 DOI: 10.3390/biology10070672] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Revised: 06/19/2021] [Accepted: 07/14/2021] [Indexed: 01/10/2023]
Abstract
Simple Summary The cerebrospinal fluid (CSF) flows through and around the central nervous system to nourish, cleanse, and support the brain and spinal cord. Though abnormalities of this CSF flow have been linked to multiple human neural diseases, little is known about the underlying mechanics of CSF flow. This study was designed to test the hypothesis that movement of the body’s trunk could cause CSF flow; hence, the study was conducted on a snake, an animal with prominent trunk movement. The results demonstrate that the resting snake has a CSF pressure profile that is very similar to what is seen in humans and other mammals, and that the CSF dynamics are changed during either artificial (manual) or natural (locomotor) movement of the snake’s body Abstract In the viper boa (Candoia aspera), the cerebrospinal fluid (CSF) shows two stable overlapping patterns of pulsations: low-frequency (0.08 Hz) pulses with a mean amplitude of 4.1 mmHg that correspond to the ventilatory cycle, and higher-frequency (0.66 Hz) pulses with a mean amplitude of 1.2 mmHg that correspond to the cardiac cycle. Manual oscillations of anesthetized C. aspera induced propagating sinusoidal body waves. These waves resulted in a different pattern of CSF pulsations with frequencies corresponding to the displacement frequency of the body and with amplitudes greater than those of the cardiac or ventilatory cycles. After recovery from anesthesia, the snakes moved independently using lateral undulation and concertina locomotion. The episodes of lateral undulation produced similar influences on the CSF pressure as were observed during the manual oscillations, though the induced CSF pulsations were of lower amplitude during lateral undulation. No impact on the CSF was found while C. aspera was performing concertina locomotion. The relationship between the propagation of the body and the CSF pulsations suggests that the body movements produce an impulse on the spinal CSF.
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Naseri Kouzehgarani G, Feldsien T, Engelhard HH, Mirakhur KK, Phipps C, Nimmrich V, Clausznitzer D, Lefebvre DR. Harnessing cerebrospinal fluid circulation for drug delivery to brain tissues. Adv Drug Deliv Rev 2021; 173:20-59. [PMID: 33705875 DOI: 10.1016/j.addr.2021.03.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 02/10/2021] [Accepted: 03/01/2021] [Indexed: 12/31/2022]
Abstract
Initially thought to be useful only to reach tissues in the immediate vicinity of the CSF circulatory system, CSF circulation is now increasingly viewed as a viable pathway to deliver certain therapeutics deeper into brain tissues. There is emerging evidence that this goal is achievable in the case of large therapeutic proteins, provided conditions are met that are described herein. We show how fluid dynamic modeling helps predict infusion rate and duration to overcome high CSF turnover. We posit that despite model limitations and controversies, fluid dynamic models, pharmacokinetic models, preclinical testing, and a qualitative understanding of the glymphatic system circulation can be used to estimate drug penetration in brain tissues. Lastly, in addition to highlighting landmark scientific and medical literature, we provide practical advice on formulation development, device selection, and pharmacokinetic modeling. Our review of clinical studies suggests a growing interest for intra-CSF delivery, particularly for targeted proteins.
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Raitamaa L, Huotari N, Korhonen V, Helakari H, Koivula A, Kananen J, Kiviniemi V. Spectral analysis of physiological brain pulsations affecting the BOLD signal. Hum Brain Mapp 2021; 42:4298-4313. [PMID: 34037278 PMCID: PMC8356994 DOI: 10.1002/hbm.25547] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 05/18/2021] [Accepted: 05/19/2021] [Indexed: 12/17/2022] Open
Abstract
Physiological pulsations have been shown to affect the global blood oxygen level dependent (BOLD) signal in human brain. While these pulsations have previously been regarded as noise, recent studies show their potential as biomarkers of brain pathology. We used the extended 5 Hz spectral range of magnetic resonance encephalography (MREG) data to investigate spatial and frequency distributions of physiological BOLD signal sources. Amplitude spectra of the global image signals revealed cardiorespiratory envelope modulation (CREM) peaks, in addition to the previously known very low frequency (VLF) and cardiorespiratory pulsations. We then proceeded to extend the amplitude of low frequency fluctuations (ALFF) method to each of these pulsations. The respiratory pulsations were spatially dominating over most brain structures. The VLF pulsations overcame the respiratory pulsations in frontal and parietal gray matter, whereas cardiac and CREM pulsations had this effect in central cerebrospinal fluid (CSF) spaces and major blood vessels. A quasi‐periodic pattern (QPP) analysis showed that the CREM pulsations propagated as waves, with a spatiotemporal pattern differing from that of respiratory pulsations, indicating them to be distinct intracranial physiological phenomenon. In conclusion, the respiration has a dominant effect on the global BOLD signal and directly modulates cardiovascular brain pulsations.
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Affiliation(s)
- Lauri Raitamaa
- Oulu Functional Neuro Imaging Group, Research Unit of Medical Imaging Physics and Technology (MIPT), University of Oulu, Oulu.,Department of Diagnostic Radiology, Medical Research Center (MRC), Oulu University Hospital, Oulu
| | - Niko Huotari
- Oulu Functional Neuro Imaging Group, Research Unit of Medical Imaging Physics and Technology (MIPT), University of Oulu, Oulu.,Department of Diagnostic Radiology, Medical Research Center (MRC), Oulu University Hospital, Oulu
| | - Vesa Korhonen
- Oulu Functional Neuro Imaging Group, Research Unit of Medical Imaging Physics and Technology (MIPT), University of Oulu, Oulu.,Department of Diagnostic Radiology, Medical Research Center (MRC), Oulu University Hospital, Oulu
| | - Heta Helakari
- Oulu Functional Neuro Imaging Group, Research Unit of Medical Imaging Physics and Technology (MIPT), University of Oulu, Oulu.,Department of Diagnostic Radiology, Medical Research Center (MRC), Oulu University Hospital, Oulu
| | - Anssi Koivula
- Oulu Functional Neuro Imaging Group, Research Unit of Medical Imaging Physics and Technology (MIPT), University of Oulu, Oulu.,Department of Diagnostic Radiology, Medical Research Center (MRC), Oulu University Hospital, Oulu
| | - Janne Kananen
- Oulu Functional Neuro Imaging Group, Research Unit of Medical Imaging Physics and Technology (MIPT), University of Oulu, Oulu.,Department of Diagnostic Radiology, Medical Research Center (MRC), Oulu University Hospital, Oulu
| | - Vesa Kiviniemi
- Oulu Functional Neuro Imaging Group, Research Unit of Medical Imaging Physics and Technology (MIPT), University of Oulu, Oulu.,Department of Diagnostic Radiology, Medical Research Center (MRC), Oulu University Hospital, Oulu
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38
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Eide PK, Valnes LM, Lindstrøm EK, Mardal KA, Ringstad G. Direction and magnitude of cerebrospinal fluid flow vary substantially across central nervous system diseases. Fluids Barriers CNS 2021; 18:16. [PMID: 33794929 PMCID: PMC8017867 DOI: 10.1186/s12987-021-00251-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 03/20/2021] [Indexed: 11/10/2022] Open
Abstract
Background Several central nervous system diseases are associated with disturbed cerebrospinal fluid (CSF) flow patterns and have typically been characterized in vivo by phase-contrast magnetic resonance imaging (MRI). This technique is, however, limited by its applicability in space and time. Phase-contrast MRI has yet to be compared directly with CSF tracer enhanced imaging, which can be considered gold standard for assessing long-term CSF flow dynamics within the intracranial compartment. Methods Here, we studied patients with various CSF disorders and compared MRI biomarkers of CSF space anatomy and phase-contrast MRI at level of the aqueduct and cranio-cervical junction with dynamic intrathecal contrast-enhanced MRI using the contrast agent gadobutrol as CSF tracer. Tracer enrichment of cerebral ventricles was graded 0–4 by visual assessment. An intracranial pressure (ICP) score was used as surrogate marker of intracranial compliance. Results The study included 94 patients and disclosed marked variation of CSF flow measures across disease categories. The grade of supra-aqueductal reflux of tracer varied, with strong reflux (grades 3–4) in half of patients. Ventricular tracer reflux correlated with stroke volume and aqueductal CSF pressure gradient. CSF flow in the cerebral aqueduct was retrograde (from 4th to 3rd ventricle) in one third of patients, with estimated CSF net flow volume about 1.0 L/24 h. In the cranio-cervical junction, net flow was cranially directed in 78% patients, with estimated CSF net flow volume about 4.7 L/24 h. Conclusions The present observations provide in vivo quantitative evidence for substantial variation in direction and magnitude of CSF flow, with re-direction of aqueductal flow in communicating hydrocephalus, and significant extra-cranial CSF production. The grading of ventricular reflux of tracer shows promise as a clinical useful method to assess CSF flow pattern disturbances in patients. Graphic abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s12987-021-00251-6.
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Affiliation(s)
- Per Kristian Eide
- Deptartment of Neurosurgery, Oslo University Hospital-Rikshospitalet, Nydalen, PB 4950, 0424, Oslo, Norway. .,Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.
| | - Lars Magnus Valnes
- Deptartment of Neurosurgery, Oslo University Hospital-Rikshospitalet, Nydalen, PB 4950, 0424, Oslo, Norway
| | - Erika Kristina Lindstrøm
- Department of Mathematics, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway.,Institute for Cancer Genetics and Informatics, Oslo University Hospital, Oslo, Norway
| | - Kent-Andre Mardal
- Department of Mathematics, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway.,Department of Numerical Analysis and Scientific Computing, Simula Research Laboratory, Oslo, Norway
| | - Geir Ringstad
- Department. of Radiology, Oslo University Hospital-Rikshospitalet, Oslo, Norway
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39
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Young BA, Adams J, Beary JM, Mardal KA, Schneider R, Kondrashova T. Variations in the cerebrospinal fluid dynamics of the American alligator (Alligator mississippiensis). Fluids Barriers CNS 2021; 18:11. [PMID: 33712028 PMCID: PMC7953579 DOI: 10.1186/s12987-021-00248-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Accepted: 03/04/2021] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Studies of mammalian CSF dynamics have been focused on three things: paravascular flow, pressure and pulsatility, and "bulk" flow; and three (respective) potential motive forces have been identified: vasomotor, cardiac, and ventilatory. There are unresolved questions in each area, and few links between the different areas. The American alligator (Alligator mississippiensis) has pronounced plasticity in its ventilatory and cardiovascular systems. This study was designed to test the hypothesis that the greater cardiovascular and ventilatory plasticity of A. mississippiensis would result in more variation within the CSF dynamics of this species. METHODS Pressure transducers were surgically implanted into the cranial subarachnoid space of 12 sub-adult alligators; CSF pressure and pulsatility were monitored along with EKG and the exhalatory gases. In four of the alligators a second pressure transducer was implanted into the spinal subarachnoid space. In five of the alligators the CSF was labeled with artificial microspheres and Doppler ultrasonography used to quantify aspects of the spinal CSF flow. RESULTS Both temporal and frequency analyses of the CSF pulsations showed highly variable contributions of both the cardiac and ventilatory cycles. Unlike the mammalian condition, the CSF pressure pulsations in the alligator are often of long (~ 3 s) duration, and similar duration CSF unidirectional flow pulses were recorded along the spinal cord. Reduction of the duration of the CSF pulsations, as during tachycardia, can lead to a "summation" of the pulsations. There appears to be a minimum duration (~ 1 s) of isolated CSF pulsations. Simultaneous recordings of cranial and spinal CSF pressures reveal a 200 ms delay in the propagation of the pressure pulse from the cranium to the vertebral canal. CONCLUSIONS Most of the CSF flow dynamics recorded from the alligators, are similar to what has been reported from studies of the human CSF. It is hypothesized that the link between ventilatory mechanics and CSF pulsations in the alligator is mediated by displacement of the spinal dura. The results of the study suggest that understanding the CSF dynamics of Alligator may provide unique insights into the evolutionary origins and functional regulation of the human CSF dynamics.
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Affiliation(s)
- Bruce A Young
- Department of Anatomy, Kirksville College of Osteopathic Medicine, A.T. Still University, Kirksville, MO, 63501, USA.
| | - James Adams
- Department of Anatomy, Kirksville College of Osteopathic Medicine, A.T. Still University, Kirksville, MO, 63501, USA
| | - Jonathan M Beary
- Behavioral Neuroscience, Kirksville College of Osteopathic Medicine, A.T. Still University, Kirksville, MO, 63501, USA
| | | | - Robert Schneider
- Family Medicine, Kirksville College of Osteopathic Medicine, A.T. Still University, Kirksville, MO, 63501, USA
| | - Tatyana Kondrashova
- Family Medicine, Kirksville College of Osteopathic Medicine, A.T. Still University, Kirksville, MO, 63501, USA
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40
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Attarpour A, Ward J, Chen JJ. Vascular origins of low-frequency oscillations in the cerebrospinal fluid signal in resting-state fMRI: Interpretation using photoplethysmography. Hum Brain Mapp 2021; 42:2606-2622. [PMID: 33638224 PMCID: PMC8090775 DOI: 10.1002/hbm.25392] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 02/09/2021] [Accepted: 02/16/2021] [Indexed: 12/12/2022] Open
Abstract
In vivo mapping of cerebrovascular oscillations in the 0.05–0.15 Hz remains difficult. Oscillations in the cerebrospinal fluid (CSF) represent a possible avenue for noninvasively tracking these oscillations using resting‐state functional MRI (rs‐fMRI), and have been used to correct for vascular oscillations in rs‐fMRI functional connectivity. However, the relationship between low‐frequency CSF and vascular oscillations remains unclear. In this study, we investigate this relationship using fast simultaneous rs‐fMRI and photoplethysmogram (PPG), examining the 0.1 Hz PPG signal, heart‐rate variability (HRV), pulse‐intensity ratio (PIR), and the second derivative of the PPG (SDPPG). The main findings of this study are: (a) signals in different CSF regions are not equivalent in their associations with vascular and tissue rs‐fMRI signals; (b) the PPG signal is maximally coherent with the arterial and CSF signals at the cardiac frequency, but coherent with brain tissue at ~0.2 Hz; (c) PIR is maximally coherent with the CSF signal near 0.03 Hz; and (d) PPG‐related vascular oscillations only contribute to ~15% of the CSF (and arterial) signal in rs‐fMRI. These findings caution against averaging all CSF regions when extracting physiological nuisance regressors in rs‐fMRI applications, and indicate the drivers of the CSF signal are more than simply cardiac. Our study is an initial attempt at the refinement and standardization of how the CSF signal in rs‐fMRI can be used and interpreted. It also paves the way for using rs‐fMRI in the CSF as a potential tool for tracking cerebrovascular health through, for instance, the potential relationship between PIR and the CSF signal.
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Affiliation(s)
- Ahmadreza Attarpour
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - James Ward
- Rotman Research Institute, Baycrest Health Sciences, Toronto, Ontario, Canada
| | - J Jean Chen
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.,Rotman Research Institute, Baycrest Health Sciences, Toronto, Ontario, Canada
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41
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Troyetsky DE, Tithof J, Thomas JH, Kelley DH. Dispersion as a waste-clearance mechanism in flow through penetrating perivascular spaces in the brain. Sci Rep 2021; 11:4595. [PMID: 33633194 PMCID: PMC7907360 DOI: 10.1038/s41598-021-83951-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 02/10/2021] [Indexed: 01/31/2023] Open
Abstract
Accumulation of metabolic wastes in the brain is correlated with several neurodegenerative disorders, including Alzheimer's disease. Waste transport and clearance occur via dispersion, the combined effect of diffusion and advection by flow of fluid. We examine the relative contributions of diffusion and advection in the perivascular spaces (PVSs) that surround penetrating cortical blood vessels and are filled with cerebrospinal fluid (CSF). To do so, we adapt prior analytic predictions of dispersion to the context of PVSs. We also perform advection-diffusion simulations in PVS-like geometries with parameters relevant to transport of amyloid-[Formula: see text] (associated with Alzheimer's) in a variety of flows, motivated by in vivo measurements. Specifically, we examine solute transport in steady and unsteady Poiseuille flows in an open (not porous) concentric circular annulus. We find that a purely oscillatory flow enhances dispersion only weakly and does not produce significant transport, whereas a steady flow component, even if slow, clears waste more effectively.
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Affiliation(s)
- Daniel E Troyetsky
- Department of Mechanical Engineering, University of Rochester, Rochester, 14627, NY, USA
| | - Jeffrey Tithof
- Department of Mechanical Engineering, University of Rochester, Rochester, 14627, NY, USA
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, 55455, MN, USA
| | - John H Thomas
- Department of Mechanical Engineering, University of Rochester, Rochester, 14627, NY, USA
| | - Douglas H Kelley
- Department of Mechanical Engineering, University of Rochester, Rochester, 14627, NY, USA.
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42
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Daversin-Catty C, Vinje V, Mardal KA, Rognes ME. The mechanisms behind perivascular fluid flow. PLoS One 2020; 15:e0244442. [PMID: 33373419 PMCID: PMC7771676 DOI: 10.1371/journal.pone.0244442] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 12/09/2020] [Indexed: 11/26/2022] Open
Abstract
Flow of cerebrospinal fluid (CSF) in perivascular spaces (PVS) is one of the key concepts involved in theories concerning clearance from the brain. Experimental studies have demonstrated both net and oscillatory movement of microspheres in PVS (Mestre et al. (2018), Bedussi et al. (2018)). The oscillatory particle movement has a clear cardiac component, while the mechanisms involved in net movement remain disputed. Using computational fluid dynamics, we computed the CSF velocity and pressure in a PVS surrounding a cerebral artery subject to different forces, representing arterial wall expansion, systemic CSF pressure changes and rigid motions of the artery. The arterial wall expansion generated velocity amplitudes of 60-260 μm/s, which is in the upper range of previously observed values. In the absence of a static pressure gradient, predicted net flow velocities were small (<0.5 μm/s), though reaching up to 7 μm/s for non-physiological PVS lengths. In realistic geometries, a static systemic pressure increase of physiologically plausible magnitude was sufficient to induce net flow velocities of 20-30 μm/s. Moreover, rigid motions of the artery added to the complexity of flow patterns in the PVS. Our study demonstrates that the combination of arterial wall expansion, rigid motions and a static CSF pressure gradient generates net and oscillatory PVS flow, quantitatively comparable with experimental findings. The static CSF pressure gradient required for net flow is small, suggesting that its origin is yet to be determined.
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Affiliation(s)
- Cécile Daversin-Catty
- Simula Research Laboratory, Department of Numerical Analysis and Scientific Computing, Lysaker, Norway
| | - Vegard Vinje
- Simula Research Laboratory, Department of Numerical Analysis and Scientific Computing, Lysaker, Norway
| | - Kent-André Mardal
- Simula Research Laboratory, Department of Numerical Analysis and Scientific Computing, Lysaker, Norway
- Department of Mathematics, University of Oslo, Oslo, Norway
| | - Marie E. Rognes
- Simula Research Laboratory, Department of Numerical Analysis and Scientific Computing, Lysaker, Norway
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43
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Young BA, Adams J, Beary JM, Mardal KA, Schneider R, Kondrashova T. The myodural bridge of the American alligator ( Alligator mississippiensis) alters CSF flow. J Exp Biol 2020; 223:jeb230896. [PMID: 33077640 DOI: 10.1242/jeb.230896] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 10/11/2020] [Indexed: 12/19/2022]
Abstract
Disorders of the volume, pressure or circulation of the cerebrospinal fluid (CSF) lead to disease states in both newborns and adults; despite this significance, there is uncertainty regarding the basic mechanics of the CSF. The suboccipital muscles connect to the dura surrounding the spinal cord, forming a complex termed the 'myodural bridge'. This study tests the hypothesis that the myodural bridge functions to alter the CSF circulation. The suboccipital muscles of American alligators were surgically exposed and electrically stimulated simultaneously with direct recordings of CSF pressure and flow. Contraction of the suboccipital muscles significantly changed both CSF flow and pressure. By demonstrating another influence on CSF circulation and pulsatility, the present study increases our understanding of the mechanics underlying the movement of the CSF.
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Affiliation(s)
- Bruce A Young
- Department of Anatomy, Kirksville College of Osteopathic Medicine, A.T. Still University, Kirksville, MO 63501, USA
| | - James Adams
- Department of Anatomy, Kirksville College of Osteopathic Medicine, A.T. Still University, Kirksville, MO 63501, USA
| | - Jonathan M Beary
- Department of Behavioral Neuroscience, Kirksville College of Osteopathic Medicine, A.T. Still University, Kirksville, MO 63501, USA
| | | | - Robert Schneider
- Department of Family Medicine, Kirksville College of Osteopathic Medicine, A.T. Still University, Kirksville, MO 63501, USA
| | - Tatyana Kondrashova
- Department of Family Medicine, Kirksville College of Osteopathic Medicine, A.T. Still University, Kirksville, MO 63501, USA
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Rasmussen TR, Meulengracht KC. Direct measurement of the rhythmic motions of the human head identifies a third rhythm. J Bodyw Mov Ther 2020; 26:24-29. [PMID: 33992252 DOI: 10.1016/j.jbmt.2020.08.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 07/21/2020] [Accepted: 08/29/2020] [Indexed: 11/28/2022]
Abstract
INTRODUCTION Central to the osteopathic cranial field, and at the same time controversial, is the concept of a unique rhythmic movement believed to originate from a primary respiratory mechanism (PRM). Further, the PRM is reported to manifest as a cranial rhythmic impulse (CRI) on the living human skull. This study explores the rhythmic oscillations of the human head measured directly as physical movements. The aim is to investigate the existence of a third rhythm distinct from the head movements caused by respiratory breathing and arterial pulsing, in an objective and purely experimental study. EXPERIMENTAL In 50 healthy individuals, rhythmic oscillations of the head were measured in real-time for 42 min in a supine resting state without any intervention. A newly developed machine for tracking rhythmic movements was used for measurements. RESULTS In all individuals, a third rhythm was distinguished as separate from the arterial and respiratory rhythm at all times. The third rhythm was observed as a dynamic physiological phenomenon with a narrow range in resting healthy individuals with a mean of 6.16 cycles/minute (4.25-7.07). The significant contribution to the amplitude of the measured movements was the respiratory breathing and this third rhythm, whereas the contribution from the arterial pulsing were minor. CONCLUSION The present study demonstrates the existence, and normative range of a third physical rhythm detected on the human head. Having developed an objective approach to studying this third rhythm might form the future basis for clinical and physiological studies of craniosacral function and dysfunction.
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45
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Gil B, Li B, Gao A, Yang GZ. Miniaturized Piezo Force Sensor for a Medical Catheter and Implantable Device. ACS APPLIED ELECTRONIC MATERIALS 2020; 2:2669-2677. [PMID: 32879913 PMCID: PMC7450887 DOI: 10.1021/acsaelm.0c00538] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 08/03/2020] [Indexed: 05/04/2023]
Abstract
Real-time monitoring of intrabody pressures can benefit from the use of miniaturized force sensors during surgical interventions or for the recovery period thereafter. Herein, we present a force sensor made of poly(vinylidene fluoride)-co-trifluoroethylene (P(VDF-TrFE)) with a simple fabrication process that has been integrated into the tip of a medical catheter for intraluminal pressure monitoring, as well as into an implantable device with a power consumption of 180 μW obtained by the near-field communication (NFC) interface to monitor the arterial pulse at the subcutaneous level (≤1 cm). The pressure range supported by the sensor is below 40 kPa, with a signal responsivity of 0.63 μV/Pa and a mean lifetime expectancy of 400 000 loading cycles inside physiological conditions (12 kPa). The proposed sensor has been tested experimentally with synthetic anatomical models for the lungs (bronchoscopy) and subcutaneous tissue, as well as directly above the human carotid and radial arteries. Information about these pressure levels can provide insights about tissue homeostasis inside the body as fluid dynamics are altered in some health conditions affecting the hemodynamic and endocrine body systems, whereas for surgical interventions, precise control and estimation of the pressure exerted by a catheter over the internal walls are necessary to avoid endothelium injuries that lead to bleeding, liquid extravasation, or flow alteration associated with atheroma formation.
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Affiliation(s)
- Bruno Gil
- The
Hamlyn Centre, Imperial College London, South Kensington, London SW7 2AZ, U.K.
| | - Bing Li
- The
UK DRI Care Research and Technology Centre, Department of Brain Science, Imperial College London, London W12 0NN, U.K.
| | - Anzhu Gao
- Institute
of Medical Robotics, Shanghai Jiao Tong
University, Shanghai 200240, China
| | - Guang-Zhong Yang
- Institute
of Medical Robotics, Shanghai Jiao Tong
University, Shanghai 200240, China
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46
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Kedarasetti RT, Drew PJ, Costanzo F. Arterial pulsations drive oscillatory flow of CSF but not directional pumping. Sci Rep 2020; 10:10102. [PMID: 32572120 PMCID: PMC7308311 DOI: 10.1038/s41598-020-66887-w] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 05/28/2020] [Indexed: 01/05/2023] Open
Abstract
The brain lacks a traditional lymphatic system for metabolite clearance. The existence of a "glymphatic system" where metabolites are removed from the brain's extracellular space by convective exchange between interstitial fluid (ISF) and cerebrospinal fluid (CSF) along the paravascular spaces (PVS) around cerebral blood vessels has been controversial. While recent work has shown clear evidence of directional flow of CSF in the PVS in anesthetized mice, the driving force for the observed fluid flow remains elusive. The heartbeat-driven peristaltic pulsation of arteries has been proposed as a probable driver of directed CSF flow. In this study, we use rigorous fluid dynamic simulations to provide a physical interpretation for peristaltic pumping of fluids. Our simulations match the experimental results and show that arterial pulsations only drive oscillatory motion of CSF in the PVS. The observed directional CSF flow can be explained by naturally occurring and/or experimenter-generated pressure differences.
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Affiliation(s)
- Ravi Teja Kedarasetti
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, United States
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, United States
| | - Patrick J Drew
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, United States
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, United States
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, United States
- Department of Neurosurgery, The Pennsylvania State University, University Park, PA, United States
| | - Francesco Costanzo
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, United States.
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, United States.
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, United States.
- Department of Mathematics, The Pennsylvania State University, University Park, PA, United States.
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47
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Kananen J, Helakari H, Korhonen V, Huotari N, Järvelä M, Raitamaa L, Raatikainen V, Rajna Z, Tuovinen T, Nedergaard M, Jacobs J, LeVan P, Ansakorpi H, Kiviniemi V. Respiratory-related brain pulsations are increased in epilepsy-a two-centre functional MRI study. Brain Commun 2020; 2:fcaa076. [PMID: 32954328 PMCID: PMC7472909 DOI: 10.1093/braincomms/fcaa076] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 04/29/2020] [Accepted: 05/05/2020] [Indexed: 01/03/2023] Open
Abstract
Resting-state functional MRI has shown potential for detecting changes in cerebral blood oxygen level-dependent signal in patients with epilepsy, even in the absence of epileptiform activity. Furthermore, it has been suggested that coefficient of variation mapping of fast functional MRI signal may provide a powerful tool for the identification of intrinsic brain pulsations in neurological diseases such as dementia, stroke and epilepsy. In this study, we used fast functional MRI sequence (magnetic resonance encephalography) to acquire ten whole-brain images per second. We used the functional MRI data to compare physiological brain pulsations between healthy controls (n = 102) and patients with epilepsy (n = 33) and furthermore to drug-naive seizure patients (n = 9). Analyses were performed by calculating coefficient of variation and spectral power in full band and filtered sub-bands. Brain pulsations in the respiratory-related frequency sub-band (0.11-0.51 Hz) were significantly (P < 0.05) increased in patients with epilepsy, with an increase in both signal variance and power. At the individual level, over 80% of medicated and drug-naive seizure patients exhibited areas of abnormal brain signal power that correlated well with the known clinical diagnosis, while none of the controls showed signs of abnormality with the same threshold. The differences were most apparent in the basal brain structures, respiratory centres of brain stem, midbrain and temporal lobes. Notably, full-band, very low frequency (0.01-0.1 Hz) and cardiovascular (0.8-1.76 Hz) brain pulses showed no differences between groups. This study extends and confirms our previous results of abnormal fast functional MRI signal variance in epilepsy patients. Only respiratory-related brain pulsations were clearly increased with no changes in either physiological cardiorespiratory rates or head motion between the subjects. The regional alterations in brain pulsations suggest that mechanisms driving the cerebrospinal fluid homeostasis may be altered in epilepsy. Magnetic resonance encephalography has both increased sensitivity and high specificity for detecting the increased brain pulsations, particularly in times when other tools for locating epileptogenic areas remain inconclusive.
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Affiliation(s)
- Janne Kananen
- Oulu Functional NeuroImaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu 90029, Finland
- Medical Imaging, Physics and Technology (MIPT), Faculty of Medicine, University of Oulu, Oulu 90220, Finland
- Medical Research Center (MRC), Oulu 90220, Finland
| | - Heta Helakari
- Oulu Functional NeuroImaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu 90029, Finland
- Medical Imaging, Physics and Technology (MIPT), Faculty of Medicine, University of Oulu, Oulu 90220, Finland
- Medical Research Center (MRC), Oulu 90220, Finland
| | - Vesa Korhonen
- Oulu Functional NeuroImaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu 90029, Finland
- Medical Imaging, Physics and Technology (MIPT), Faculty of Medicine, University of Oulu, Oulu 90220, Finland
- Medical Research Center (MRC), Oulu 90220, Finland
| | - Niko Huotari
- Oulu Functional NeuroImaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu 90029, Finland
- Medical Imaging, Physics and Technology (MIPT), Faculty of Medicine, University of Oulu, Oulu 90220, Finland
- Medical Research Center (MRC), Oulu 90220, Finland
| | - Matti Järvelä
- Oulu Functional NeuroImaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu 90029, Finland
- Medical Imaging, Physics and Technology (MIPT), Faculty of Medicine, University of Oulu, Oulu 90220, Finland
- Medical Research Center (MRC), Oulu 90220, Finland
| | - Lauri Raitamaa
- Oulu Functional NeuroImaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu 90029, Finland
- Medical Imaging, Physics and Technology (MIPT), Faculty of Medicine, University of Oulu, Oulu 90220, Finland
- Medical Research Center (MRC), Oulu 90220, Finland
| | - Ville Raatikainen
- Oulu Functional NeuroImaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu 90029, Finland
- Medical Imaging, Physics and Technology (MIPT), Faculty of Medicine, University of Oulu, Oulu 90220, Finland
- Medical Research Center (MRC), Oulu 90220, Finland
| | - Zalan Rajna
- Oulu Functional NeuroImaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu 90029, Finland
- Center for Machine Vision and Signal Analysis (CMVS), University of Oulu, Oulu 90014, Finland
| | - Timo Tuovinen
- Oulu Functional NeuroImaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu 90029, Finland
- Medical Imaging, Physics and Technology (MIPT), Faculty of Medicine, University of Oulu, Oulu 90220, Finland
- Medical Research Center (MRC), Oulu 90220, Finland
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY 14642, USA
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2200, Denmark
| | - Julia Jacobs
- Department of Pediatric Neurology and Muscular Disease, University Medical Center Freiburg, Faculty of Medicine, University of Freiburg, Freiburg 79110, Germany
- Department of Paediatrics, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
- Department of Neuroscience, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
- Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Pierre LeVan
- Department of Paediatrics, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
- Department of Neuroscience, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
- Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
- Department of Radiology, Medical Physics, University Medical Center Freiburg, Faculty of Medicine, University of Freiburg, Freiburg 79110, Germany
- Department of Radiology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Hanna Ansakorpi
- Medical Research Center (MRC), Oulu 90220, Finland
- Research Unit of Neuroscience, Neurology, University of Oulu, Oulu 90220, Finland
- Department of Neurology, Oulu University Hospital, Oulu 90029, Finland
| | - Vesa Kiviniemi
- Oulu Functional NeuroImaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu 90029, Finland
- Medical Imaging, Physics and Technology (MIPT), Faculty of Medicine, University of Oulu, Oulu 90220, Finland
- Medical Research Center (MRC), Oulu 90220, Finland
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48
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Vinje V, Eklund A, Mardal KA, Rognes ME, Støverud KH. Intracranial pressure elevation alters CSF clearance pathways. Fluids Barriers CNS 2020; 17:29. [PMID: 32299464 PMCID: PMC7161287 DOI: 10.1186/s12987-020-00189-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 03/28/2020] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Infusion testing is a common procedure to determine whether shunting will be beneficial in patients with normal pressure hydrocephalus. The method has a well-developed theoretical foundation and corresponding mathematical models that describe the CSF circulation from the choroid plexus to the arachnoid granulations. Here, we investigate to what extent the proposed glymphatic or paravascular pathway (or similar pathways) modifies the results of the traditional mathematical models. METHODS We used a compartment model to estimate pressure in the subarachnoid space and the paravascular spaces. For the arachnoid granulations, the cribriform plate and the glymphatic circulation, resistances were calculated and used to estimate pressure and flow before and during an infusion test. Finally, different variations to the model were tested to evaluate the sensitivity of selected parameters. RESULTS At baseline intracranial pressure (ICP), we found a very small paravascular flow directed into the subarachnoid space, while 60% of the fluid left through the arachnoid granulations and 40% left through the cribriform plate. However, during the infusion, 80% of the fluid left through the arachnoid granulations, 20% through the cribriform plate and flow in the PVS was stagnant. Resistance through the glymphatic system was computed to be 2.73 mmHg/(mL/min), considerably lower than other fluid pathways, giving non-realistic ICP during infusion if combined with a lymphatic drainage route. CONCLUSIONS The relative distribution of CSF flow to different clearance pathways depends on ICP, with the arachnoid granulations as the main contributor to outflow. As such, ICP increase is an important factor that should be addressed when determining the pathways of injected substances in the subarachnoid space. Our results suggest that the glymphatic resistance is too high to allow for pressure driven flow by arterial pulsations and at the same time too small to allow for a direct drainage route from PVS to cervical lymphatics.
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Affiliation(s)
- Vegard Vinje
- Department of Scientific Computing and Numerical Analysis, Simula Research Laboratory, Lysaker, Norway.
| | - Anders Eklund
- Department of Radiation Sciences, Umeå University, Umeå, Sweden
| | - Kent-Andre Mardal
- Department of Scientific Computing and Numerical Analysis, Simula Research Laboratory, Lysaker, Norway.,Department of Mathematics, University of Oslo, Oslo, Norway
| | - Marie E Rognes
- Department of Scientific Computing and Numerical Analysis, Simula Research Laboratory, Lysaker, Norway
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49
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Jakimovski D, Zivadinov R, Weinstock-Guttman B, Bergsland N, Dwyer MG, Lagana MM. Longitudinal analysis of cerebral aqueduct flow measures: multiple sclerosis flow changes driven by brain atrophy. Fluids Barriers CNS 2020; 17:9. [PMID: 32000809 PMCID: PMC6993504 DOI: 10.1186/s12987-020-0172-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Accepted: 01/21/2020] [Indexed: 12/28/2022] Open
Abstract
Background Several small cross-sectional studies have investigated cerebrospinal fluid (CSF) flow dynamics in multiple sclerosis (MS) patients and have reported mixed results. Currently, there are no longitudinal studies that investigate CSF dynamics in MS patients. Objective To determine longitudinal changes in CSF dynamics measured at the level of aqueduct of Sylvius (AoS) in MS patients and matched healthy controls (HCs). Materials and methods Forty (40) MS patients and 20 HCs underwent 3T MRI cine phase contrast imaging with velocity-encoded pulse-gated sequence at baseline and 5-year follow-up. For atrophy determination, MS patients underwent additional high-resolution 3D T1-weighted imaging. Measures of AoS cross-sectional area (CSA), average systolic and diastolic velocity peaks, maximal systolic and diastolic velocity peaks and average CSF flow rates were determined. Brain atrophy and ventricular CSF (vCSF) expansion rates were determined. Cross-sectional and longitudinal changes were derived by analysis of covariance (ANCOVA) and paired repeated tests. Confirmatory general linear models were also performed. False discovery rate (FDR)-corrected p-values lower than 0.05 were considered significant. Results The MS population demonstrated significant increase in maximal diastolic peak (from 7.23 to 7.86 cm/s, non-adjusted p = 0.037), diastolic peak flow rate (7.76 ml/min to 9.33 ml/min, non-adjusted p = 0.023) and AoS CSA (from 3.12 to 3.69 mm2, adjusted p = 0.001). The only differentiator between MS patients and HCs was the greater AoS CSA (3.58 mm2 vs. 2.57 mm2, age- and sex-adjusted ANCOVA, p = 0.045). The AoS CSA change was associated with vCSF expansion rate (age- and sex-adjusted Spearman’s correlation r = 0.496, p = 0.019) and not with baseline nor change in maximal velocity. The expansion rate of the vCSF space explained an additional 23.8% of variance in change of AoS CSA variance when compared to age and sex alone (R2 = 0.273, t = 2.557, standardized β = 0.51, and p = 0.019). Conclusion MS patients present with significant longitudinal AoS enlargement, potentially due to regional atrophy changes and ex-vacuo expansion of the aqueduct.
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Affiliation(s)
- Dejan Jakimovski
- Buffalo Neuroimaging Analysis Center (BNAC), Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY, USA
| | - Robert Zivadinov
- Buffalo Neuroimaging Analysis Center (BNAC), Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY, USA.,Center for Biomedical Imaging at Clinical Translational Science Institute, University at Buffalo, State University of New York, Buffalo, NY, USA
| | - Bianca Weinstock-Guttman
- Jacobs Comprehensive MS Treatment and Research Center, Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY, USA
| | - Niels Bergsland
- Buffalo Neuroimaging Analysis Center (BNAC), Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY, USA.,MRI Laboratory, CADiTeR, IRCCS, Fondazione Don Carlo Gnocchi ONLUS, Via Alfonso Capecelatro 66, 20148, Milan, Italy
| | - Michael G Dwyer
- Buffalo Neuroimaging Analysis Center (BNAC), Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY, USA
| | - Marcella Maria Lagana
- MRI Laboratory, CADiTeR, IRCCS, Fondazione Don Carlo Gnocchi ONLUS, Via Alfonso Capecelatro 66, 20148, Milan, Italy.
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