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Ocular Lymphatic and Glymphatic Systems: Implications for Retinal Health and Disease. Int J Mol Sci 2022; 23:ijms231710139. [PMID: 36077535 PMCID: PMC9456449 DOI: 10.3390/ijms231710139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 09/01/2022] [Accepted: 09/02/2022] [Indexed: 11/17/2022] Open
Abstract
Clearance of ocular fluid and metabolic waste is a critical function of the eye in health and disease. The eye has distinct fluid outflow pathways in both the anterior and posterior segments. Although the anterior outflow pathway is well characterized, little is known about posterior outflow routes. Recent studies suggest that lymphatic and glymphatic systems play an important role in the clearance of fluid and waste products from the posterior segment of the eye. The lymphatic system is a vascular network that runs parallel to the blood circulatory system. It plays an essential role in maintenance of fluid homeostasis and immune surveillance in the body. Recent studies have reported lymphatics in the cornea (under pathological conditions), ciliary body, choroid, and optic nerve meninges. The evidence of lymphatics in optic nerve meninges is, however, limited. An alternative lymphatic system termed the glymphatic system was recently discovered in the rodent eye and brain. This system is a glial cell-based perivascular network responsible for the clearance of interstitial fluid and metabolic waste. In this review, we will discuss our current knowledge of ocular lymphatic and glymphatic systems and their role in retinal degenerative diseases.
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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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Zhu Y, Rodriguez-Paras C, Rhee J, Mehta RK. Methodological Approaches and Recommendations for Functional Near-Infrared Spectroscopy Applications in HF/E Research. HUMAN FACTORS 2020; 62:613-642. [PMID: 31107601 DOI: 10.1177/0018720819845275] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
OBJECTIVE The objective of this study was to systematically document current methods and protocols employed when using functional near-infrared spectroscopy (fNIRS) techniques in human factors and ergonomics (HF/E) research and generate recommendations for conducting and reporting fNIRS findings in HF/E applications. METHOD A total of 1,687 articles were identified through Ovid-MEDLINE, PubMed, Web of Science, and Scopus databases, of which 37 articles were included in the review based on review inclusion/exclusion criteria. RESULTS A majority of the HF/E fNIRS investigations were found in transportation, both ground and aviation, and in assessing cognitive (e.g., workload, working memory) over physical constructs. There were large variations pertaining to data cleaning, processing, and analysis approaches across the studies that warrant standardization of methodological approaches. The review identified major challenges in transparency and reporting of important fNIRS data collection and analyses specifications that diminishes study replicability, introduces potential biases, and increases likelihood of inaccurate results. As such, results reported in existing fNIRS studies need to be cautiously approached. CONCLUSION To improve the quality of fNIRS investigations and/or to facilitate its adoption and integration in different HF/E applications, such as occupational ergonomics and rehabilitation, recommendations for fNIRS data collection, processing, analysis, and reporting are provided.
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Affiliation(s)
- Yibo Zhu
- 14736 Texas A&M University, College Station, USA
| | | | - Joohyun Rhee
- 14736 Texas A&M University, College Station, USA
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Coenen W, Gutiérrez-Montes C, Sincomb S, Criado-Hidalgo E, Wei K, King K, Haughton V, Martínez-Bazán C, Sánchez AL, Lasheras JC. Subject-Specific Studies of CSF Bulk Flow Patterns in the Spinal Canal: Implications for the Dispersion of Solute Particles in Intrathecal Drug Delivery. AJNR Am J Neuroradiol 2019; 40:1242-1249. [PMID: 31196863 PMCID: PMC7048533 DOI: 10.3174/ajnr.a6097] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 05/08/2019] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Recent flow dynamics studies have shown that the eccentricity of the spinal cord affects the magnitude and characteristics of the slow bulk motion of CSF in the spinal subarachnoid space, which is an important variable in solute transport along the spinal canal. The goal of this study was to investigate how anatomic differences among subjects affect this bulk flow. MATERIALS AND METHODS T2-weighted spinal images were obtained in 4 subjects and repeated in 1 subject after repositioning. CSF velocity was calculated from phase-contrast MR images for 7 equally spaced levels along the length of the spine. This information was input into a 2-time-scale asymptotic analysis of the Navier-Stokes and concentration equations to calculate the short- and long-term CSF flow in the spinal subarachnoid space. Bulk flow streamlines were shown for each subject and position and inspected for differences in patterns. RESULTS The 4 subjects had variable degrees of lordosis and kyphosis. Repositioning in 1 subject changed the degree of cervical lordosis and thoracic kyphosis. The streamlines of bulk flow show the existence of distinct regions where the fluid particles flow in circular patterns. The location and interconnectivity of these recirculating regions varied among individuals and different positions. CONCLUSIONS Lordosis, kyphosis, and spinal cord eccentricity in the healthy human spine result in subject-specific patterns of bulk flow recirculating regions. The extent of the interconnectivity of the streamlines among these recirculating regions is fundamental in determining the long-term transport of solute particles along the spinal canal.
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Affiliation(s)
- W Coenen
- From the Departments of Mechanical and Aerospace Engineering (W.C., S.S., E.C.-H., A.L.S., J.C.L.)
| | - C Gutiérrez-Montes
- Department of Mechanical and Mining Engineering (C.G.-M., C.M.-B.), University of Jaén, Jaén, Andalucía, Spain
| | - S Sincomb
- From the Departments of Mechanical and Aerospace Engineering (W.C., S.S., E.C.-H., A.L.S., J.C.L.)
| | - E Criado-Hidalgo
- From the Departments of Mechanical and Aerospace Engineering (W.C., S.S., E.C.-H., A.L.S., J.C.L.)
| | - K Wei
- MRI Center (K.W., K.K.), Huntington Medical Research Institutes, Pasadena, California
| | - K King
- MRI Center (K.W., K.K.), Huntington Medical Research Institutes, Pasadena, California
| | - V Haughton
- Department of Radiology (V.H.), School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
| | - C Martínez-Bazán
- Department of Mechanical and Mining Engineering (C.G.-M., C.M.-B.), University of Jaén, Jaén, Andalucía, Spain
| | - A L Sánchez
- From the Departments of Mechanical and Aerospace Engineering (W.C., S.S., E.C.-H., A.L.S., J.C.L.)
| | - J C Lasheras
- From the Departments of Mechanical and Aerospace Engineering (W.C., S.S., E.C.-H., A.L.S., J.C.L.)
- Bioengineering (J.C.L.), University of California, San Diego, San Diego, California
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Aktas G, Kollmeier JM, Joseph AA, Merboldt KD, Ludwig HC, Gärtner J, Frahm J, Dreha-Kulaczewski S. Spinal CSF flow in response to forced thoracic and abdominal respiration. Fluids Barriers CNS 2019; 16:10. [PMID: 30947716 PMCID: PMC6449937 DOI: 10.1186/s12987-019-0130-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 03/27/2019] [Indexed: 11/15/2022] Open
Abstract
Background Respiration-induced pressure changes represent a powerful driving force of CSF dynamics as previously demonstrated using flow-sensitive real-time magnetic resonance imaging (MRI). The purpose of the present study was to elucidate the sensitivity of CSF flow along the spinal canal to forced thoracic versus abdominal respiration. Methods Eighteen subjects without known illness were studied using real-time phase-contrast flow MRI at 3 T in the aqueduct and along the spinal canal at levels C3, Th1, Th8 and L3. Subjects performed a protocol of forced breathing comprising four cycles of 2.5 s inspiration and 2.5 s expiration. Results The quantitative results for spinal CSF flow rates and volumes confirm previous findings of an upward movement during forced inspiration and reversed downward flow during subsequent exhalation—for both breathing types. However, the effects were more pronounced for abdominal than for thoracic breathing, in particular at spinal levels Th8 and L3. In general, CSF net flow volumes were very similar for both breathing conditions pointing upwards in all locations. Conclusions Spinal CSF dynamics are sensitive to varying respiratory performances. The different CSF flow volumes in response to deep thoracic versus abdominal breathing reflect instantaneous adjustments of intrathoracic and intraabdominal pressure, respectively. Real-time MRI access to CSF flow in response to defined respiration patterns will be of clinical importance for patients with disturbed CSF circulation like hydrocephalus, pseudotumor cerebri and others. Electronic supplementary material The online version of this article (10.1186/s12987-019-0130-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Gökmen Aktas
- School of Medicine, University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Jost M Kollmeier
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, 37077, Göttingen, Germany
| | - Arun A Joseph
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, 37077, Göttingen, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Germany
| | - Klaus-Dietmar Merboldt
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, 37077, Göttingen, Germany
| | - Hans-Christoph Ludwig
- Division of Pediatric Neurosurgery, Department of Neurosurgery, 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
| | - Jens Frahm
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, 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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Matsumae M, Kuroda K, Yatsushiro S, Hirayama A, Hayashi N, Takizawa K, Atsumi H, Sorimachi T. Changing the Currently Held Concept of Cerebrospinal Fluid Dynamics Based on Shared Findings of Cerebrospinal Fluid Motion in the Cranial Cavity Using Various Types of Magnetic Resonance Imaging Techniques. Neurol Med Chir (Tokyo) 2019; 59:133-146. [PMID: 30814424 PMCID: PMC6465527 DOI: 10.2176/nmc.ra.2018-0272] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The “cerebrospinal fluid (CSF) circulation theory” of CSF flowing unidirectionally and circulating through the ventricles and subarachnoid space in a downward or upward fashion has been widely recognized. In this review, observations of CSF motion using different magnetic resonance imaging (MRI) techniques are described, findings that are shared among these techniques are extracted, and CSF motion, as we currently understand it based on the results from the quantitative analysis of CSF motion, is discussed, along with a discussion of slower water molecule motion in the perivascular, paravascular, and brain parenchyma. Today, a shared consensus regarding CSF motion is being formed, as follows: CSF motion is not a circulatory flow, but a combination of various directions of flow in the ventricles and subarachnoid space, and the acceleration of CSF motion differs depending on the CSF space. It is now necessary to revise the currently held concept that CSF flows unidirectionally. Currently, water molecule motion in the order of centimeters per second can be detected with various MRI techniques. Thus, we need new MRI techniques with high-velocity sensitivity, such as in the order of 10 μm/s, to determine water molecule movement in the vessel wall, paravascular space, and brain parenchyma. In this paper, the authors review the previous and current concepts of CSF motion in the central nervous system using various MRI techniques.
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Affiliation(s)
| | - Kagayaki Kuroda
- Department of Human and Information Sciences, School of Information Science and Technology, Tokai University
| | - Satoshi Yatsushiro
- Department of Human and Information Sciences, School of Information Science and Technology, Tokai University.,BioView Inc., Tokyo, Japan
| | | | - Naokazu Hayashi
- Department of Neurosurgery, Tokai University School of Medicine
| | - Ken Takizawa
- Department of Ophthalmology, Tokai University School of Medicine
| | - Hideki Atsumi
- Department of Neurosurgery, Tokai University School of Medicine
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Cerebrospinal Fluid Dynamics and Intrathecal Delivery. Neuromodulation 2018. [DOI: 10.1016/b978-0-12-805353-9.00067-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Daouk J, Bouzerar R, Baledent O. Heart rate and respiration influence on macroscopic blood and CSF flows. Acta Radiol 2017; 58:977-982. [PMID: 28273732 DOI: 10.1177/0284185116676655] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Background Changes in blood volume in the intracranial arteries and the resulting oscillations of brain parenchyma have been presumed as main initiating factors of cerebrospinal fluid (CSF) pulsations. However, respiration has been recently supposed to influence CSF dynamics via thoracic pressure changes. Purpose To measure blood and CSF cervical flow and quantify the contribution of cardiac and respiratory cycles on the subsequent signal evolution. Material and Methods Sixteen volunteers were enrolled. All participant underwent two-dimensional fast field echo echo planar imaging (FFE-EPI). Regions of interest were placed on internal carotids, jugular veins, and rachidian canal to extract temporal profiles. Spectral analysis was performed to extract respiratory and cardiac frequencies. The contribution of respiration and cardiac activity was assessed to signal evolution by applying a multiple linear model. Results Mean respiratory frequency was 14.6 ± 3.9 cycles per min and mean heart rate was 66.8 ± 9 cycles per min. Cardiac contribution was higher than breathing for internal carotids, explaining 74.68% and 10.27% of the signal variance, respectively. For the jugular veins, respiratory component was higher than the cardiac one contributing 44.28% and 6.53% of the signal variance, respectively. For CSF, breathing and cardiac component contributed less than half of signal variance (12.61% and 23.23%, respectively). Conclusion Respiration and cardiac activity both influence fluid flow at the cervical level. Arterial inflow is driven by the cardiac pool whereas venous blood aspiration seems more due to thoracic pressure changes. CSF dynamics acts as a buffer between these two blood compartments.
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Affiliation(s)
- Joël Daouk
- Bioflow Image Unit, Jules Verne University of Picardie, Amiens, France
| | - Roger Bouzerar
- Bioflow Image Unit, Jules Verne University of Picardie, Amiens, France
- Medical Image Processing Unit, Amiens University Medical Center, Amiens, France
| | - Olivier Baledent
- Bioflow Image Unit, Jules Verne University of Picardie, Amiens, France
- Medical Image Processing Unit, Amiens University Medical Center, Amiens, France
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Yildiz S, Thyagaraj S, Jin N, Zhong X, Heidari Pahlavian S, Martin BA, Loth F, Oshinski J, Sabra KG. Quantifying the influence of respiration and cardiac pulsations on cerebrospinal fluid dynamics using real-time phase-contrast MRI. J Magn Reson Imaging 2017; 46:431-439. [DOI: 10.1002/jmri.25591] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 11/28/2016] [Indexed: 02/05/2023] Open
Affiliation(s)
- Selda Yildiz
- Woodruff School of Mechanical Engineering; Georgia Institute of Technology; Atlanta Georgia USA
| | - Suraj Thyagaraj
- Department of Mechanical Engineering, Conquer Chiari Research Center; University of Akron; Akron Ohio USA
| | - Ning Jin
- MR R&D Collaborations; Siemens Healthcare; Columbus Ohio USA
| | - Xiaodong Zhong
- MR R&D Collaborations; Siemens Healthcare; Atlanta Georgia USA
- Department of Radiology; Emory University; Atlanta Georgia USA
| | - Soroush Heidari Pahlavian
- Department of Mechanical Engineering, Conquer Chiari Research Center; University of Akron; Akron Ohio USA
| | - Bryn A. Martin
- Department of Biological Engineering; University of Idaho; Moscow Idaho USA
| | - Francis Loth
- Department of Mechanical Engineering, Conquer Chiari Research Center; University of Akron; Akron Ohio USA
| | - John Oshinski
- Department of Radiology & Imaging Sciences and Biomedical Engineering; Emory University; Atlanta Georgia USA
| | - Karim G. Sabra
- Woodruff School of Mechanical Engineering; Georgia Institute of Technology; Atlanta Georgia USA
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Dynamics of respiratory and cardiac CSF motion revealed with real-time simultaneous multi-slice EPI velocity phase contrast imaging. Neuroimage 2015; 122:281-7. [PMID: 26241682 DOI: 10.1016/j.neuroimage.2015.07.073] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2015] [Revised: 06/22/2015] [Accepted: 07/24/2015] [Indexed: 11/20/2022] Open
Abstract
Cerebrospinal fluid (CSF) dynamics have been mostly studied with cardiac-gated phase contrast MRI combining signal from many cardiac cycles to create cine-phase sampling of one time-averaged cardiac cycle. The relative effects of cardiac and respiratory changes on CSF movement are not well understood. There is possible respiration-driven movement of CSF in ventricles, cisterns, and subarachnoid spaces which has not been characterized with velocity measurements. To date, commonly used cine-phase contrast techniques of velocity imaging inherently cannot detect respiratory velocity changes since cardiac-gated data acquired over several minutes randomizes respiratory phase contributions. We have developed an extremely fast, real-time, and quantitative MRI technique to image CSF velocity in simultaneous multi-slice (SMS) echo planar imaging (EPI) acquisitions of 3 or 6 slice levels simultaneously over 30s and observe 3D spatial distributions of CSF velocity. Measurements were made in 10 subjects utilizing a respiratory belt to record respiratory phases and visual cues to instruct subjects on breathing rates. A protocol is able to measure velocity within regions of brain and basal cisterns covered with 24 axial slices in 4 minutes, repeated for 3 velocity directions. These measurements were performed throughout the whole brain, rather than in selected line regions so that a global view of CSF dynamics could be visualized. Observations of cardiac and breathing-driven CSF dynamics show bidirectional respiratory motion occurs primarily along the central axis through the basal cisterns and intraventricular passageways and to a lesser extent in the peripheral Sylvian fissure with little CSF motion present in subarachnoid spaces. During inspiration phase, there is upward (inferior to superior) CSF movement into the cranial cavity and lateral ventricles and a reversal of direction in expiration phase.
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Abstract
The mechanisms behind CSF flow in humans are still not fully known. CSF circulates from its primary production sites at the choroid plexus through the brain ventricles to reach the outer surface of the brain in the subarachnoid spaces from where it drains into venous bloodstream and cervical lymphatics. According to a recent concept of brain fluid transport, established in rodents, CSF from the brain surface also enters the brain tissue along para-arterial routes and exits through paravenous spaces again into subarachnoid compartments. This unidirectional flow is mainly driven by arterial pulsation. To investigate how CSF flow is regulated in humans, we applied a novel real-time magnetic resonance imaging technique at high spatial (0.75 mm) and temporal (50 ms) resolution in healthy human subjects. We observed significant CSF flow exclusively with inspiration. In particular, during forced breathing, high CSF flow was elicited during every inspiration, whereas breath holding suppressed it. Only a minor flow component could be ascribed to cardiac pulsation. The present results unambiguously identify inspiration as the most important driving force for CSF flow in humans. Inspiratory thoracic pressure reduction is expected to directly modulate the hydrostatic pressure conditions for the low-resistance paravenous, venous, and lymphatic clearance routes of CSF. Furthermore, the experimental approach opens new clinical opportunities to study the pathophysiology of various forms of hydrocephalus and to design therapeutic strategies in relation to CSF flow alterations.
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HIRAYAMA A, MATSUMAE M, YATSUSHIRO S, ABDULLA A, ATSUMI H, KURODA K. Visualization of Pulsatile CSF Motion Around Membrane-like Structures with both 4D Velocity Mapping and Time-SLIP Technique. Magn Reson Med Sci 2015; 14:263-73. [DOI: 10.2463/mrms.2014-0089] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
| | | | - Satoshi YATSUSHIRO
- Course of Information Science and Engineering, Tokai University Graduate School of Engineering
| | | | - Hideki ATSUMI
- Department of Neurosurgery, Tokai University School of Medicine
| | - Kagayaki KURODA
- Course of Information Science and Engineering, Tokai University Graduate School of Engineering
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Boubela RN, Kalcher K, Nasel C, Moser E. Scanning fast and slow: current limitations of 3 Tesla functional MRI and future potential. FRONTIERS IN PHYSICS 2014; 2:00001. [PMID: 28164083 PMCID: PMC5291320 DOI: 10.3389/fphy.2014.00001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Functional MRI at 3T has become a workhorse for the neurosciences, e.g., neurology, psychology, and psychiatry, enabling non-invasive investigation of brain function and connectivity. However, BOLD-based fMRI is a rather indirect measure of brain function, confounded by physiology related signals, e.g., head or brain motion, brain pulsation, blood flow, intermixed with susceptibility differences close or distant to the region of neuronal activity. Even though a plethora of preprocessing strategies have been published to address these confounds, their efficiency is still under discussion. In particular, physiological signal fluctuations closely related to brain supply may mask BOLD signal changes related to "true" neuronal activation. Here we explore recent technical and methodological advancements aimed at disentangling the various components, employing fast multiband vs. standard EPI, in combination with fast temporal ICA. Our preliminary results indicate that fast (TR <0.5 s) scanning may help to identify and eliminate physiologic components, increasing tSNR and functional contrast. In addition, biological variability can be studied and task performance better correlated to other measures. This should increase specificity and reliability in fMRI studies. Furthermore, physiological signal changes during scanning may then be recognized as a source of information rather than a nuisance. As we are currently still undersampling the complexity of the brain, even at a rather coarse macroscopic level, we should be very cautious in the interpretation of neuroscientific findings, in particular when comparing different groups (e.g., age, sex, medication, pathology, etc.). From a technical point of view our goal should be to sample brain activity at layer specific resolution with low TR, covering as much of the brain as possible without violating SAR limits. We hope to stimulate discussion toward a better understanding and a more quantitative use of fMRI.
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Affiliation(s)
- Roland N. Boubela
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
- MR Center of Excellence, Medical University of Vienna, Vienna, Austria
| | - Klaudius Kalcher
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
- MR Center of Excellence, Medical University of Vienna, Vienna, Austria
| | - Christian Nasel
- MR Center of Excellence, Medical University of Vienna, Vienna, Austria
- Department of Radiology, State Clinical Center Danube District, Tulln, Austria
| | - Ewald Moser
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
- MR Center of Excellence, Medical University of Vienna, Vienna, Austria
- Brain Behavior Laboratory, Department Psychiatry, University of Pennsylvania Medical Center, Philadelphia, PA, USA
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Scholkmann F, Kleiser S, Metz AJ, Zimmermann R, Mata Pavia J, Wolf U, Wolf M. A review on continuous wave functional near-infrared spectroscopy and imaging instrumentation and methodology. Neuroimage 2014; 85 Pt 1:6-27. [PMID: 23684868 DOI: 10.1016/j.neuroimage.2013.05.004] [Citation(s) in RCA: 993] [Impact Index Per Article: 99.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 04/12/2013] [Accepted: 05/03/2013] [Indexed: 01/09/2023] Open
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15
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Yamada S, Miyazaki M, Yamashita Y, Ouyang C, Yui M, Nakahashi M, Shimizu S, Aoki I, Morohoshi Y, McComb JG. Influence of respiration on cerebrospinal fluid movement using magnetic resonance spin labeling. Fluids Barriers CNS 2013; 10:36. [PMID: 24373186 PMCID: PMC3895787 DOI: 10.1186/2045-8118-10-36] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 12/21/2013] [Indexed: 11/27/2022] Open
Abstract
Background Magnetic resonance imaging (MRI) cardiac gated phase contrast (PC) cine techniques have non-invasively shown the effect of the cardiac pulse on cerebrospinal fluid (CSF) movement. Echo planar imaging (EPI) has shown CSF movement as influenced by both cardiac pulsation and respiration. Previously, it has not been possible to visualize CSF movement in response to respiration non-invasively. The present study was undertaken to do so. Methods The effect of respiration on CSF movement was investigated using a non-contrast time-spatial labeling inversion pulse (Time-SLIP) with balanced steady-state free precession (bSSFP) readout. CSF movement was observed in the intracranial compartment in response to respirations in ten normal volunteers. To elucidate the respiration effect, the acquisition was triggered at the beginning of deep inhalation, deep exhalation and breath holding. Results By employing this respiration-induced spin labeling bSSFP cine method, we were able to visualize CSF movement induced by respiratory excursions. CSF moved cephalad (16.4 ± 7.7 mm) during deep inhalation and caudad (11.6 ± 3.0 mm) during deep exhalation in the prepontine cisternal area. Small but rapid cephalad (3.0 ± 0.4 mm) and caudad (3.0 ± 0.5 mm) movement was observed in the same region during breath holding and is thought to reflect cardiac pulsations. Conclusions The Time-SLIP bSSFP cine technique allows for non-invasive visualization of CSF movement associated with respiration to a degree not previously reported.
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Affiliation(s)
| | - Mitsue Miyazaki
- Toshiba Medical Research Institute USA, Inc,, 706 N, Deerpath Drive, Vernon Hills, Illinois 60061, USA.
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Mandl RCW, Schnack HG, Zwiers MP, Kahn RS, Hulshoff Pol HE. Functional diffusion tensor imaging at 3 Tesla. Front Hum Neurosci 2013; 7:817. [PMID: 24409133 PMCID: PMC3847896 DOI: 10.3389/fnhum.2013.00817] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 11/11/2013] [Indexed: 11/13/2022] Open
Abstract
In a previous study we reported on a non-invasive functional diffusion tensor imaging (fDTI) method to measure neuronal signals directly from subtle changes in fractional anisotropy along white matter tracts. We hypothesized that these fractional anisotropy changes relate to morphological changes of glial cells induced by axonal activity. In the present study we set out to replicate the results of the previous study with an improved fDTI scan acquisition scheme. A group of twelve healthy human participants were scanned on a 3 Tesla MRI scanner. Activation was revealed in the contralateral thalamo-cortical tract and optic radiations during tactile and visual stimulation, respectively. Mean percent signal change in FA was 3.47% for the tactile task and 3.79% for the visual task, while for the MD the mean percent signal change was only -0.10 and -0.09%. The results support the notion of different response functions for tactile and visual stimuli. With this study we successfully replicated our previous findings using the same types of stimuli but on a different group of healthy participants and at different field-strength. The successful replication of our first fDTI results suggests that the non-invasive fDTI method is robust enough to study the functional neural networks in the human brain within a practically feasible time period.
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Affiliation(s)
- René C W Mandl
- 1Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht Utrecht, Netherlands
| | - Hugo G Schnack
- 1Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht Utrecht, Netherlands
| | - Marcel P Zwiers
- 2Radboud University Nijmegen, Donders Institute for Brain, Cognition and Behaviour Centre for Cognitive Neuroimaging Nijmegen, Netherlands
| | - René S Kahn
- 1Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht Utrecht, Netherlands
| | - Hilleke E Hulshoff Pol
- 1Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht Utrecht, Netherlands
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Transfer function analysis of respiratory and cardiac pulsations in human brain observed on dynamic magnetic resonance images. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2013; 2013:157040. [PMID: 23710249 PMCID: PMC3655443 DOI: 10.1155/2013/157040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Accepted: 03/27/2013] [Indexed: 11/23/2022]
Abstract
Magnetic resonance (MR) imaging provides a noninvasive, in vivo imaging technique for studying respiratory and cardiac pulsations in human brains, because these pulsations can be recorded as flow-related enhancement on dynamic MR images. By applying independent component analysis to dynamic MR images, respiratory and cardiac pulsations were observed. Using the signal-time curves of these pulsations as reference functions, the magnitude and phase of the transfer function were calculated on a pixel-by-pixel basis. The calculated magnitude and phase represented the amplitude change and temporal delay at each pixel as compared with the reference functions. In the transfer function analysis, near constant phases were found at the respiratory and cardiac frequency bands, indicating the existence of phase delay relative to the reference functions. In analyzing the dynamic MR images using the transfer function analysis, we found the following: (1) a good delineation of temporal delay of these pulsations can be achieved; (2) respiratory pulsation exists in the ventricular and cortical cerebrospinal fluid; (3) cardiac pulsation exists in the ventricular cerebrospinal fluid and intracranial vessels; and (4) a 180-degree phase delay or inverted amplitude is observed on phase images.
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Kao YH, Teng MMH, Liu KC, Lam IP, Lin YC. Hemodynamic segmentation of MR perfusion images in patients with unilateral carotid stenosis using independent component analysis. J Magn Reson Imaging 2008; 28:1125-32. [DOI: 10.1002/jmri.21537] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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