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Terem I, Younes K, Wang N, Condron P, Abderezaei J, Kumar H, Vossler H, Kwon E, Kurt M, Mormino E, Holdsworth S, Setsompop K. 3D Quantitative-Amplified Magnetic Resonance Imaging (3D q-aMRI). Bioengineering (Basel) 2024; 11:851. [PMID: 39199808 PMCID: PMC11352018 DOI: 10.3390/bioengineering11080851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2024] [Revised: 08/03/2024] [Accepted: 08/13/2024] [Indexed: 09/01/2024] Open
Abstract
Amplified MRI (aMRI) is a promising new technique that can visualize pulsatile brain tissue motion by amplifying sub-voxel motion in cine MRI data, but it lacks the ability to quantify the sub-voxel motion field in physical units. Here, we introduce a novel post-processing algorithm called 3D quantitative amplified MRI (3D q-aMRI). This algorithm enables the visualization and quantification of pulsatile brain motion. 3D q-aMRI was validated and optimized on a 3D digital phantom and was applied in vivo on healthy volunteers for its ability to accurately measure brain parenchyma and CSF voxel displacement. Simulation results show that 3D q-aMRI can accurately quantify sub-voxel motions in the order of 0.01 of a voxel size. The algorithm hyperparameters were optimized and tested on in vivo data. The repeatability and reproducibility of 3D q-aMRI were shown on six healthy volunteers. The voxel displacement field extracted by 3D q-aMRI is highly correlated with the displacement measurements estimated by phase contrast (PC) MRI. In addition, the voxel displacement profile through the cerebral aqueduct resembled the CSF flow profile reported in previous literature. Differences in brain motion was observed in patients with dementia compared with age-matched healthy controls. In summary, 3D q-aMRI is a promising new technique that can both visualize and quantify pulsatile brain motion. Its ability to accurately quantify sub-voxel motion in physical units holds potential for the assessment of pulsatile brain motion as well as the indirect assessment of CSF homeostasis. While further research is warranted, 3D q-aMRI may provide important diagnostic information for neurological disorders such as Alzheimer's disease.
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Affiliation(s)
- Itamar Terem
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Kyan Younes
- Department of Neurology & Neurological Sciences, Stanford University, Stanford, CA 94305, USA; (K.Y.); (H.V.); (E.M.)
| | - Nan Wang
- Department of Radiology, Stanford University, Stanford, CA 94305, USA;
| | - Paul Condron
- Mātai Medical Research Institute, Tairāwhiti-Gisborne 4010, New Zealand; (P.C.); (E.K.); (S.H.)
| | - Javid Abderezaei
- Department of Mechanical Engineering, University of Washington, Seattle, WA 98195, USA; (J.A.); (M.K.)
| | - Haribalan Kumar
- General Electric Healthcare, Tairāwhiti-Gisborne 4010, New Zealand;
| | - Hillary Vossler
- Department of Neurology & Neurological Sciences, Stanford University, Stanford, CA 94305, USA; (K.Y.); (H.V.); (E.M.)
| | - Eryn Kwon
- Mātai Medical Research Institute, Tairāwhiti-Gisborne 4010, New Zealand; (P.C.); (E.K.); (S.H.)
- Auckland Bioengineering Institute, University of Auckland, Auckland 1010, New Zealand
- Department of Anatomy and Medical Imaging—Faculty of Medical and Health Sciences & Centre for Brain Research, University of Auckland, Auckland 1010, New Zealand
| | - Mehmet Kurt
- Department of Mechanical Engineering, University of Washington, Seattle, WA 98195, USA; (J.A.); (M.K.)
| | - Elizabeth Mormino
- Department of Neurology & Neurological Sciences, Stanford University, Stanford, CA 94305, USA; (K.Y.); (H.V.); (E.M.)
| | - Samantha Holdsworth
- Mātai Medical Research Institute, Tairāwhiti-Gisborne 4010, New Zealand; (P.C.); (E.K.); (S.H.)
- Department of Anatomy and Medical Imaging—Faculty of Medical and Health Sciences & Centre for Brain Research, University of Auckland, Auckland 1010, New Zealand
| | - Kawin Setsompop
- Department of Radiology, Stanford University, Stanford, CA 94305, USA;
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De Falco E, Solcà M, Bernasconi F, Babo-Rebelo M, Young N, Sammartino F, Tallon-Baudry C, Navarro V, Rezai AR, Krishna V, Blanke O. Single neurons in the thalamus and subthalamic nucleus process cardiac and respiratory signals in humans. Proc Natl Acad Sci U S A 2024; 121:e2316365121. [PMID: 38451949 PMCID: PMC10945861 DOI: 10.1073/pnas.2316365121] [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: 09/27/2023] [Accepted: 01/16/2024] [Indexed: 03/09/2024] Open
Abstract
Visceral signals are constantly processed by our central nervous system, enable homeostatic regulation, and influence perception, emotion, and cognition. While visceral processes at the cortical level have been extensively studied using non-invasive imaging techniques, very few studies have investigated how this information is processed at the single neuron level, both in humans and animals. Subcortical regions, relaying signals from peripheral interoceptors to cortical structures, are particularly understudied and how visceral information is processed in thalamic and subthalamic structures remains largely unknown. Here, we took advantage of intraoperative microelectrode recordings in patients undergoing surgery for deep brain stimulation (DBS) to investigate the activity of single neurons related to cardiac and respiratory functions in three subcortical regions: ventral intermedius nucleus (Vim) and ventral caudalis nucleus (Vc) of the thalamus, and subthalamic nucleus (STN). We report that the activity of a large portion of the recorded neurons (about 70%) was modulated by either the heartbeat, the cardiac inter-beat interval, or the respiration. These cardiac and respiratory response patterns varied largely across neurons both in terms of timing and their kind of modulation. A substantial proportion of these visceral neurons (30%) was responsive to more than one of the tested signals, underlining specialization and integration of cardiac and respiratory signals in STN and thalamic neurons. By extensively describing single unit activity related to cardiorespiratory function in thalamic and subthalamic neurons, our results highlight the major role of these subcortical regions in the processing of visceral signals.
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Affiliation(s)
- Emanuela De Falco
- Laboratory of Cognitive Neuroscience, School of Life Sciences, Neuro-X Institute and Brain Mind Institute, École Polytechnique Fédérale de Lausanne, Lausanne1015, Switzerland
- Department of Neuroscience, Rockefeller Neuroscience Institute–West Virginia University, Morgantown, WV26505
| | - Marco Solcà
- Laboratory of Cognitive Neuroscience, School of Life Sciences, Neuro-X Institute and Brain Mind Institute, École Polytechnique Fédérale de Lausanne, Lausanne1015, Switzerland
- Department of Psychiatry, University Hospital Geneva, Geneva1205, Switzerland
| | - Fosco Bernasconi
- Laboratory of Cognitive Neuroscience, School of Life Sciences, Neuro-X Institute and Brain Mind Institute, École Polytechnique Fédérale de Lausanne, Lausanne1015, Switzerland
| | - Mariana Babo-Rebelo
- Laboratory of Cognitive Neuroscience, School of Life Sciences, Neuro-X Institute and Brain Mind Institute, École Polytechnique Fédérale de Lausanne, Lausanne1015, Switzerland
| | - Nicole Young
- Medical Department, SpecialtyCare, Brentwood, TN37027
| | - Francesco Sammartino
- Department of Physical Medicine and Rehabilitation, The Ohio State University, Columbus, OH43210
| | - Catherine Tallon-Baudry
- Laboratoire de Neurosciences Cognitives et Computationnelles, Département d’Etudes Cognitives, École normale supérieure-Paris Sciences et Lettres University, Inserm, Paris75005, France
| | - Vincent Navarro
- Sorbonne Université, Paris Brain Institute—Institut du Cerveau et de la Moelle épinière, Inserm, CNRS, Assistance Publique - Hôpitaux de Paris, Epilepsy Unit, Hôpital de la Pitié-Salpêtrière, Paris75013, France
| | - Ali R. Rezai
- Department of Neurosurgery, Rockefeller Neuroscience Institute—West Virginia University, Morgantown, WV26505
| | - Vibhor Krishna
- Department of Neurosurgery, University of North Carolina at Chapel Hill, Durham, NC27516
| | - Olaf Blanke
- Laboratory of Cognitive Neuroscience, School of Life Sciences, Neuro-X Institute and Brain Mind Institute, École Polytechnique Fédérale de Lausanne, Lausanne1015, Switzerland
- Department of Clinical Neurosciences, University Hospital Geneva, Geneva1205, Switzerland
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3
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Voss HU, Razlighi QR. Pulsatility analysis of the circle of Willis. AGING BRAIN 2024; 5:100111. [PMID: 38495808 PMCID: PMC10940807 DOI: 10.1016/j.nbas.2024.100111] [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: 09/26/2023] [Revised: 02/13/2024] [Accepted: 02/26/2024] [Indexed: 03/19/2024] Open
Abstract
Purpose To evaluate the phenomenological significance of cerebral blood pulsatility imaging in aging research. Methods N = 38 subjects from 20 to 72 years of age (24 females) were imaged with ultrafast MRI with a sampling rate of 100 ms and simultaneous acquisition of pulse oximetry data. Of these, 28 subjects had acceptable MRI and pulse data, with 16 subjects between 20 and 28 years of age, and 12 subjects between 61 and 72 years of age. Pulse amplitude in the circle of Willis was assessed with the recently developed method of analytic phase projection to extract blood volume waveforms. Results Arteries in the circle of Willis showed pulsatility in the MRI for both the young and old age groups. Pulse amplitude in the circle of Willis significantly increased with age (p = 0.01) but was independent of gender, heart rate, and head motion during MRI. Discussion and conclusion Increased pulse wave amplitude in the circle of Willis in the elderly suggests a phenomenological significance of cerebral blood pulsatility imaging in aging research. The physiologic origin of increased pulse amplitude (increased pulse pressure vs. change in arterial morphology vs. re-shaping of pulse waveforms caused by the heart, and possible interaction with cerebrospinal fluid pulsatility) requires further investigation.
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Affiliation(s)
- Henning U. Voss
- Department of Radiology, Weill Cornell Medicine, New York, NY, USA
- Cornell MRI Facility, College of Human Ecology, Cornell University, Ithaca, NY, USA
| | - Qolamreza R. Razlighi
- Quantitative Neuroimaging Laboratory, Brain Health Imaging Institute, Department of Radiology, Weill Cornell Medicine, New York, NY, USA
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Pionteck A, Abderezaei J, Fillingham P, Chuang YC, Sakai Y, Belani P, Rigney B, De Leacy R, Fifi JT, Chien A, Colby GP, Jahan R, Duckwiler G, Sayre J, Holdsworth SJ, Mossa-Basha M, Levitt MR, Mocco J, Kurt M, Nael K. Intracranial aneurysm wall displacement depicted by amplified Flow predicts growth. J Neurointerv Surg 2024:jnis-2023-021227. [PMID: 38320850 PMCID: PMC11300705 DOI: 10.1136/jnis-2023-021227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 01/21/2024] [Indexed: 03/01/2024]
Abstract
BACKGROUND Abnormal intracranial aneurysm (IA) wall motion has been associated with IA growth and rupture. Recently, a new image processing algorithm called amplified Flow (aFlow) has been used to successfully track IA wall motion by combining the amplification of cine and four-dimensional (4D) Flow MRI. We sought to apply aFlow to assess wall motion as a potential marker of IA growth in a paired-wise analysis of patients with growing versus stable aneurysms. METHODS In this retrospective case-control study, 10 patients with growing IAs and a matched cohort of 10 patients with stable IAs who had baseline 4D Flow MRI were included. The aFlow was used to amplify and extract IA wall displacements from 4D Flow MRI. The associations of aFlow parameters with commonly used risk factors and morphometric features were assessed using paired-wise univariate and multivariate analyses. RESULTS aFlow quantitative results showed significantly (P=0.035) higher wall motion displacement depicted by mean±SD 90th% values of 2.34±0.72 in growing IAs versus 1.39±0.58 in stable IAs with an area under the curve of 0.85. There was also significantly (P<0.05) higher variability of wall deformation across IA geometry in growing versus stable IAs depicted by the dispersion variables including 121-150% larger standard deviation ([Formula: see text]) and 128-161% wider interquartile range [Formula: see text]. CONCLUSIONS aFlow-derived quantitative assessment of IA wall motion showed greater wall motion and higher variability of wall deformation in growing versus stable IAs.
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Affiliation(s)
- Aymeric Pionteck
- Mechanical Engineering, University of Washington, Seattle, Washington, USA
| | - Javid Abderezaei
- Mechanical Engineering, University of Washington, Seattle, Washington, USA
| | - Patrick Fillingham
- Neurological Surgery, University of Washington School of Medicine, Seattle, Washington, USA
| | - Ya-Chen Chuang
- Mechanical Engineering, University of Washington, Seattle, Washington, USA
| | - Yu Sakai
- Diagnostic, Molecular and Interventional Radiology, Mount Sinai Health System, New York, New York, USA
| | - Puneet Belani
- Diagnostic, Molecular and Interventional Radiology, Mount Sinai Health System, New York, New York, USA
| | - Brian Rigney
- Diagnostic, Molecular and Interventional Radiology, Mount Sinai Health System, New York, New York, USA
| | - Reade De Leacy
- Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Johanna T Fifi
- Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Aichi Chien
- Radiological Sciences, University of California, Los Angeles David Geffen School of Medicine, Los Angeles, California, USA
| | - Geoffrey P Colby
- Neurosurgery, University of California Los Angeles David Geffen School of Medicine, Los Angeles, California, USA
| | - Reza Jahan
- Radiological Sciences, University of California, Los Angeles David Geffen School of Medicine, Los Angeles, California, USA
| | - Gary Duckwiler
- Radiological Sciences, University of California, Los Angeles David Geffen School of Medicine, Los Angeles, California, USA
| | - James Sayre
- Radiological Sciences, University of California, Los Angeles David Geffen School of Medicine, Los Angeles, California, USA
| | | | - Mahmud Mossa-Basha
- Radiology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Michael R Levitt
- Neurological Surgery, University of Washington School of Medicine, Seattle, Washington, USA
| | - J Mocco
- Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Mehmet Kurt
- Mechanical Engineering, University of Washington, Seattle, Washington, USA
| | - Kambiz Nael
- Diagnostic, Molecular and Interventional Radiology, Mount Sinai Health System, New York, New York, USA
- Radiological Sciences, University of California, Los Angeles David Geffen School of Medicine, Los Angeles, California, USA
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5
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Visser VL, Caçoilo A, Rusinek H, Weickenmeier J. Mechanical loading of the ventricular wall as a spatial indicator for periventricular white matter degeneration. J Mech Behav Biomed Mater 2023; 143:105921. [PMID: 37269602 PMCID: PMC10266836 DOI: 10.1016/j.jmbbm.2023.105921] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 05/15/2023] [Accepted: 05/18/2023] [Indexed: 06/05/2023]
Abstract
Progressive white matter degeneration in periventricular and deep white matter regions appears as white matter hyperintensities (WMH) on MRI scans. To date, periventricular WMHs are often associated with vascular dysfunction. Here, we demonstrate that ventricular inflation resulting from cerebral atrophy and hemodynamic pulsation with every heartbeat leads to a mechanical loading state of periventricular tissues that significantly affects the ventricular wall. Specifically, we present a physics-based modeling approach that provides a rationale for ependymal cell involvement in periventricular WMH formation. Building on eight previously created 2D finite element brain models, we introduce novel mechanomarkers for ependymal cell loading and geometric measures that characterize lateral ventricular shape. We show that our novel mechanomarkers, such as maximum ependymal cell deformations and maximum curvature of the ventricular wall, spatially overlap with periventricular WMH locations and are sensitive predictors for WMH formation. We also explore the role of the septum pellucidum in mitigating mechanical loading of the ventricular wall by constraining the radial expansion of the lateral ventricles during loading. Our models consistently show that ependymal cells are stretched thin only in the horns of the ventricles irrespective of ventricular shape. We therefore pose that periventricular WMH etiology is strongly linked to the deterioration of the over-stretched ventricular wall resulting in CSF leakage into periventricular white matter. Subsequent secondary damage mechanisms, including vascular degeneration, exacerbate lesion formation and lead to progressive growth into deep white matter regions.
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Affiliation(s)
- Valery L Visser
- Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, NJ 07030, United States of America; Department of Biomedical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
| | - Andreia Caçoilo
- Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, NJ 07030, United States of America
| | - Henry Rusinek
- Department of Radiology, New York University Grossman School of Medicine, New York, NY 10016, United States of America
| | - Johannes Weickenmeier
- Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, NJ 07030, United States of America.
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Almudayni A, Alharbi M, Chowdhury A, Ince J, Alablani F, Minhas JS, Lecchini-Visintini A, Chung EML. Magnetic resonance imaging of the pulsing brain: a systematic review. MAGMA (NEW YORK, N.Y.) 2023; 36:3-14. [PMID: 36242710 PMCID: PMC9992013 DOI: 10.1007/s10334-022-01043-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 09/15/2022] [Accepted: 10/03/2022] [Indexed: 11/05/2022]
Abstract
OBJECTIVE To perform a systematic review of the literature exploring magnetic resonance imaging (MRI) methods for measuring natural brain tissue pulsations (BTPs) in humans. METHODS A prospective systematic search of MEDLINE, SCOPUS and OpenGrey databases was conducted by two independent reviewers using a pre-determined strategy. The search focused on identifying reported measurements of naturally occurring BTP motion in humans. Studies involving non-human participants, MRI in combination with other modalities, MRI during invasive procedures and MRI studies involving externally applied tests were excluded. Data from the retrieved records were combined to create Forest plots comparing brain tissue displacement between Chiari-malformation type 1 (CM-I) patients and healthy controls using an independent samples t-test. RESULTS The search retrieved 22 eligible articles. Articles described 5 main MRI techniques for visualisation or quantification of intrinsic brain motion. MRI techniques generally agreed that the amplitude of BTPs varies regionally from 0.04 mm to ~ 0.80 mm, with larger tissue displacements occurring closer to the centre and base of the brain compared to peripheral regions. Studies of brain pathology using MRI BTP measurements are currently limited to tumour characterisation, idiopathic intracranial hypertension (IIH), and CM-I. A pooled analysis confirmed that displacement of tissue in the cerebellar tonsillar region of CM-I patients was + 0.31 mm [95% CI 0.23, 0.38, p < 0.0001] higher than in healthy controls. DISCUSSION MRI techniques used for measurements of brain motion are at an early stage of development with high heterogeneity across the methods used. Further work is required to provide normative data to support systematic BTPs characterisation in health and disease.
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Affiliation(s)
- Alanoud Almudayni
- College of Applied Medical Sciences, Prince Sattam Bin Abdulaziz University, Al-Kharj, Saudi Arabia
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Room 419, Robert Kilpatrick Building, Leicester Royal Infirmary, Infirmary Square, Leicester, LE1 5WW UK
| | - Meshal Alharbi
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Room 419, Robert Kilpatrick Building, Leicester Royal Infirmary, Infirmary Square, Leicester, LE1 5WW UK
- College of Applied Medical Sciences, King Saud Bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | - Alimul Chowdhury
- University Hospitals of Leicester NHS Trust, Leicester, LE1 5WW UK
| | - Jonathan Ince
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Room 419, Robert Kilpatrick Building, Leicester Royal Infirmary, Infirmary Square, Leicester, LE1 5WW UK
| | - Fatmah Alablani
- College of Applied Medical Sciences, Prince Sattam Bin Abdulaziz University, Al-Kharj, Saudi Arabia
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Room 419, Robert Kilpatrick Building, Leicester Royal Infirmary, Infirmary Square, Leicester, LE1 5WW UK
| | - Jatinder Singh Minhas
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Room 419, Robert Kilpatrick Building, Leicester Royal Infirmary, Infirmary Square, Leicester, LE1 5WW UK
- National Institute for Health Research Leicester Biomedical Research Centre, University of Leicester, Leicester, LE5 4PW UK
| | - Andrea Lecchini-Visintini
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Room 419, Robert Kilpatrick Building, Leicester Royal Infirmary, Infirmary Square, Leicester, LE1 5WW UK
- School of Electronics and Computer Science, University of Southampton, Southampton, SO17 1BJ UK
| | - Emma Ming Lin Chung
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Room 419, Robert Kilpatrick Building, Leicester Royal Infirmary, Infirmary Square, Leicester, LE1 5WW UK
- University Hospitals of Leicester NHS Trust, Leicester, LE1 5WW UK
- National Institute for Health Research Leicester Biomedical Research Centre, University of Leicester, Leicester, LE5 4PW UK
- School of Life Course and Population Sciences, King’s College London, Room 3.25a, Shepherd’s House, Guy’s Campus, King’s College London, London, SE1 7EH UK
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Visser VL, Rusinek H, Weickenmeier J. Peak ependymal cell stretch overlaps with the onset locations of periventricular white matter lesions. Sci Rep 2021; 11:21956. [PMID: 34753951 PMCID: PMC8578319 DOI: 10.1038/s41598-021-00610-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 10/14/2021] [Indexed: 12/30/2022] Open
Abstract
Deep and periventricular white matter hyperintensities (dWMH/pvWMH) are bright appearing white matter tissue lesions in T2-weighted fluid attenuated inversion recovery magnetic resonance images and are frequent observations in the aging human brain. While early stages of these white matter lesions are only weakly associated with cognitive impairment, their progressive growth is a strong indicator for long-term functional decline. DWMHs are typically associated with vascular degeneration in diffuse white matter locations; for pvWMHs, however, no unifying theory exists to explain their consistent onset around the horns of the lateral ventricles. We use patient imaging data to create anatomically accurate finite element models of the lateral ventricles, white and gray matter, and cerebrospinal fluid, as well as to reconstruct their WMH volumes. We simulated the mechanical loading of the ependymal cells forming the primary brain-fluid interface, the ventricular wall, and its surrounding tissues at peak ventricular pressure during the hemodynamic cycle. We observe that both the maximum principal tissue strain and the largest ependymal cell stretch consistently localize in the anterior and posterior horns. Our simulations show that ependymal cells experience a loading state that causes the ventricular wall to be stretched thin. Moreover, we show that maximum wall loading coincides with the pvWMH locations observed in our patient scans. These results warrant further analysis of white matter pathology in the periventricular zone that includes a mechanics-driven deterioration model for the ventricular wall.
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Affiliation(s)
- Valery L Visser
- Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, NJ, 07030, USA
- Department of Biomedical Engineering, Eindhoven University of Technology, 5600 MB, Eindhoven, The Netherlands
- Institute for Regenerative Medicine, University of Zurich, Zurich, 8006, Switzerland
| | - Henry Rusinek
- Department of Radiology, New York University Grossman School of Medicine, New York, NY, 10016, USA
| | - Johannes Weickenmeier
- Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, NJ, 07030, USA.
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8
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Karakatsani ME, Pouliopoulos AN, Liu M, Jambawalikar SR, Konofagou EE. Contrast-Free Detection of Focused Ultrasound-Induced Blood-Brain Barrier Opening Using Diffusion Tensor Imaging. IEEE Trans Biomed Eng 2021; 68:2499-2508. [PMID: 33360980 DOI: 10.1109/tbme.2020.3047575] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
OBJECTIVE Focused ultrasound (FUS) has emerged as a non-invasive technique to locally and reversibly disrupt the blood-brain barrier (BBB). Here, we investigate the use of diffusion tensor imaging (DTI) as a means of detecting FUS-induced BBB opening at the absence of an MRI contrast agent. A non-human primate (NHP) was repeatedly treated with FUS and preformed circulating microbubbles to transiently disrupt the BBB (n = 4). T1- and diffusion-weighted MRI scans were acquired after the ultrasound treatment, with and without gadolinium-based contrast agent, respectively. Both scans were registered with a high-resolution T1-weighted scan of the NHP to investigate signal correlations. DTI detected an increase in fractional anisotropy from 0.21 ± 0.02 to 0.38 ± 0.03 (82.6 ± 5.2% change) within the targeted area one hour after BBB opening. Enhanced DTI contrast overlapped by 77.22 ± 9.2% with hyper-intense areas of gadolinium-enhanced T1-weighted scans, indicating diffusion anisotropy enhancement only within the BBB opening volume. Diffusion was highly anisotropic and unidirectional within the treated brain region, as indicated by the direction of the principal diffusion eigenvectors. Polar and azimuthal angle ranges decreased by 35.6% and 82.4%, respectively, following BBB opening. Evaluation of the detection methodology on a second NHP (n = 1) confirmed the across-animal feasibility of the technique. In conclusion, DTI may be used as a contrast-free MR imaging modality in lieu of contrast-enhanced T1 mapping for detecting BBB opening during focused-ultrasound treatment or evaluating BBB integrity in brain-related pathologies.
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9
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Ozkaya E, Triolo ER, Rezayaraghi F, Abderezaei J, Meinhold W, Hong K, Alipour A, Kennedy P, Fleysher L, Ueda J, Balchandani P, Eriten M, Johnson CL, Yang Y, Kurt M. Brain-mimicking phantom for biomechanical validation of motion sensitive MR imaging techniques. J Mech Behav Biomed Mater 2021; 122:104680. [PMID: 34271404 DOI: 10.1016/j.jmbbm.2021.104680] [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: 01/11/2021] [Revised: 05/07/2021] [Accepted: 06/30/2021] [Indexed: 10/20/2022]
Abstract
Motion sensitive MR imaging techniques allow for the non-invasive evaluation of biological tissues by using different excitation schemes, including physiological/intrinsic motions caused by cardiac pulsation or respiration, and vibrations caused by an external actuator. The mechanical biomarkers extracted through these imaging techniques have been shown to hold diagnostic value for various neurological disorders and conditions. Amplified MRI (aMRI), a cardiac gated imaging technique, can help track and quantify low frequency intrinsic motion of the brain. As for high frequency actuation, the mechanical response of brain tissue can be measured by applying external high frequency actuation in combination with a motion sensitive MR imaging sequence called Magnetic Resonance Elastography (MRE). Due to the frequency-dependent behavior of brain mechanics, there is a need to develop brain phantom models that can mimic the broadband mechanical response of the brain in order to validate motion-sensitive MR imaging techniques. Here, we have designed a novel phantom test setup that enables both the low and high frequency responses of a brain-mimicking phantom to be captured, allowing for both aMRI and MRE imaging techniques to be applied on the same phantom model. This setup combines two different vibration sources: a pneumatic actuator, for low frequency/intrinsic motion (1 Hz) for use in aMRI, and a piezoelectric actuator for high frequency actuation (30-60 Hz) for use in MRE. Our results show that in MRE experiments performed from 30 Hz through 60 Hz, propagating shear waves attenuate faster at higher driving frequencies, consistent with results in the literature. Furthermore, actuator coupling has a substantial effect on wave amplitude, with weaker coupling causing lower amplitude wave field images, specifically shown in the top-surface shear loading configuration. For intrinsic actuation, our results indicate that aMRI linearly amplifies motion up to at least an amplification factor of 9 for instances of both visible and sub-voxel motion, validated by varying power levels of pneumatic actuation (40%-80% power) under MR, and through video analysis outside the MRI scanner room. While this investigation used a homogeneous brain-mimicking phantom, our setup can be used to study the mechanics of non-homogeneous phantom configurations with bio-interfaces in the future.
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Affiliation(s)
- E Ozkaya
- Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, NJ, 07030, USA.
| | - E R Triolo
- Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, NJ, 07030, USA
| | - F Rezayaraghi
- Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, NJ, 07030, USA
| | - J Abderezaei
- Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, NJ, 07030, USA
| | - W Meinhold
- The George W. Woodruff of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - K Hong
- BioMedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - A Alipour
- BioMedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - P Kennedy
- BioMedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - L Fleysher
- BioMedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - J Ueda
- The George W. Woodruff of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - P Balchandani
- BioMedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - M Eriten
- Department of Mechanical Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - C L Johnson
- Department of Biomedical Engineering, University of Deleware, Newark, DE, 19716, USA
| | - Y Yang
- BioMedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - M Kurt
- Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, NJ, 07030, USA; BioMedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
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10
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Terem I, Dang L, Champagne A, Abderezaei J, Pionteck A, Almadan Z, Lydon AM, Kurt M, Scadeng M, Holdsworth SJ. 3D amplified MRI (aMRI). Magn Reson Med 2021; 86:1674-1686. [PMID: 33949713 PMCID: PMC8252598 DOI: 10.1002/mrm.28797] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 02/18/2021] [Accepted: 03/17/2021] [Indexed: 12/17/2022]
Abstract
Purpose Amplified MRI (aMRI) has been introduced as a new method of detecting and visualizing pulsatile brain motion in 2D. Here, we improve aMRI by introducing a novel 3D aMRI approach. Methods 3D aMRI was developed and tested for its ability to amplify sub‐voxel motion in all three directions. In addition, 3D aMRI was qualitatively compared to 2D aMRI on multi‐slice and 3D (volumetric) balanced steady‐state free precession cine data and phase contrast (PC‐MRI) acquired on healthy volunteers at 3T. Optical flow maps and 4D animations were produced from volumetric 3D aMRI data. Results 3D aMRI exhibits better image quality and fewer motion artifacts compared to 2D aMRI. The tissue motion was seen to match that of PC‐MRI, with the predominant brain tissue displacement occurring in the cranial‐caudal direction. Optical flow maps capture the brain tissue motion and display the physical change in shape of the ventricles by the relative movement of the surrounding tissues. The 4D animations show the complete brain tissue and cerebrospinal fluid (CSF) motion, helping to highlight the “piston‐like” motion of the ventricles. Conclusions Here, we introduce a novel 3D aMRI approach that enables one to visualize amplified cardiac‐ and CSF‐induced brain motion in striking detail. 3D aMRI captures brain motion with better image quality than 2D aMRI and supports a larger amplification factor. The optical flow maps and 4D animations of 3D aMRI may open up exciting applications for neurological diseases that affect the biomechanics of the brain and brain fluids.
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Affiliation(s)
- Itamar Terem
- Department of Electrical Engineering, Stanford University, Stanford, California, USA.,Department of Structural Biology, Stanford University, Stanford, California, USA
| | - Leo Dang
- Department of Anatomy and Medical Imaging & Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.,Mātai Medical Research Institute, Gisborne-Tairāwhiti, New Zealand
| | - Allen Champagne
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada
| | - Javid Abderezaei
- Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, New Jersey, USA
| | - Aymeric Pionteck
- Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, New Jersey, USA
| | - Zainab Almadan
- Department of Anatomy and Medical Imaging & Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Anna-Maria Lydon
- Centre for Advanced MRI, University of Auckland, Auckland, New Zealand
| | - Mehmet Kurt
- Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, New Jersey, USA.,Biomedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Miriam Scadeng
- Department of Anatomy and Medical Imaging & Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.,Mātai Medical Research Institute, Gisborne-Tairāwhiti, New Zealand.,Department of Radiology, University of California, San Diego, California, USA
| | - Samantha J Holdsworth
- Department of Anatomy and Medical Imaging & Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.,Mātai Medical Research Institute, Gisborne-Tairāwhiti, New Zealand
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11
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Development, calibration, and testing of 3D amplified MRI (aMRI) for the quantification of intrinsic brain motion. BRAIN MULTIPHYSICS 2021. [DOI: 10.1016/j.brain.2021.100022] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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12
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Mangalore S, Vankayalapati S, Gupta AK. Hydrocephalic Dementia: Revisited with Multimodality Imaging and toward a Unified Imaging Approach. J Neurosci Rural Pract 2021; 12:412-418. [PMID: 33927533 PMCID: PMC8064848 DOI: 10.1055/s-0041-1726614] [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] [Indexed: 11/12/2022] Open
Abstract
Objective
Overlap of normal pressure hydrocephalus (NPH) and pathology proven cases of dementia is known. The objective of this paper is to correlate both the clinical and multimodality imaging findings in patients with imaging diagnosis NPH and give a hypothesis for association of clinical findings.
Methods
This is a retrospective observational analysis of 13 cases patients who were referred to molecular imaging center for imaging in 2016 to 2019, and they were divided into four groups based on structural imaging findings. Group 1 had magnetic resonance imaging (MRI) findings of diffuse effacement of sulcal spaces (DESH) and flow void, whereas Group 4 had none of these two. Group 3 had MRI findings of DESH but no flow void, and Group 2 had flow void but no DESH. Clinical presentation, MRI-PET findings of four groups are assessed.
Results
Groups with presence of flow void showed hypometabolism in the medial frontal and medial temporal lobe. Groups with presence of DESH has effacement of parietal sulci showed parietal hypo metabolism with clinical presentation AD/mixed dementia and absence of parietal effacement showed FTD-like presentation. Groups without flow void or DESH showed only mild medial temporal hypometabolism and presented with classical signs of NPH. ASL perfusion changes are in correlation with metabolism on positron emission tomography (PET)-MRI.
Conclusion
This study has led us to hypothesize the lack of outflow of brain protein and their deposition in parenchyma based on pressure gradient would be easier explanation to go with cluster of findings. MR-PET and other investigations each had different specificity and sensitivity and different pattern of presentation.
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Affiliation(s)
- Sandhya Mangalore
- Division of Neuroradiology, Department of Neuroimaging and interventional Radiology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Sriharish Vankayalapati
- Division of Neuroradiology, Department of Neuroimaging and interventional Radiology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Arun Kumar Gupta
- Division of Neuroradiology, Department of Neuroimaging and interventional Radiology, National Institute of Mental Health and Neurosciences, Bengaluru, India
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13
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Sloots JJ, Biessels GJ, de Luca A, Zwanenburg JJM. Strain Tensor Imaging: Cardiac-induced brain tissue deformation in humans quantified with high-field MRI. Neuroimage 2021; 236:118078. [PMID: 33878376 DOI: 10.1016/j.neuroimage.2021.118078] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 02/02/2021] [Accepted: 04/07/2021] [Indexed: 11/15/2022] Open
Abstract
The cardiac cycle induces blood volume pulsations in the cerebral microvasculature that cause subtle deformation of the surrounding tissue. These tissue deformations are highly relevant as a potential source of information on the brain's microvasculature as well as of tissue condition. Besides, cyclic brain tissue deformations may be a driving force in clearance of brain waste products. We have developed a high-field magnetic resonance imaging (MRI) technique to capture these tissue deformations with full brain coverage and sufficient signal-to-noise to derive the cardiac-induced strain tensor on a voxel by voxel basis, that could not be assessed non-invasively before. We acquired the strain tensor with 3 mm isotropic resolution in 9 subjects with repeated measurements for 8 subjects. The strain tensor yielded both positive and negative eigenvalues (principle strains), reflecting the Poison effect in tissue. The principle strain associated with expansion followed the known funnel shaped brain motion pattern pointing towards the foramen magnum. Furthermore, we evaluate two scalar quantities from the strain tensor: the volumetric strain and octahedral shear strain. These quantities showed consistent patterns between subjects, and yielded repeatable results: the peak systolic volumetric strain (relative to end-diastolic strain) was 4.19⋅10-4 ± 0.78⋅10-4 and 3.98⋅10-4 ± 0.44⋅10-4 (mean ± standard deviation for first and second measurement, respectively), and the peak octahedral shear strain was 2.16⋅10-3 ± 0.31⋅10-3 and 2.31⋅10-3 ± 0.38⋅10-3, for the first and second measurement, respectively. The volumetric strain was typically highest in the cortex and lowest in the periventricular white matter, while anisotropy was highest in the subcortical white matter and basal ganglia. This technique thus reveals new, regional information on the brain's cardiac-induced deformation characteristics, and has the potential to advance our understanding of the role of microvascular pulsations in health and disease.
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Affiliation(s)
| | - Geert Jan Biessels
- Neurology, UMC Utrecht Brain Center, University Medical Center Utrecht, the Netherlands
| | - Alberto de Luca
- Neurology, UMC Utrecht Brain Center, University Medical Center Utrecht, the Netherlands
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14
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Kashanian A, Binesh N, Pressman BD, Danielpour M. Utility of True Fast Imaging with Steady-State Precession in Detecting Arachnoid Veils of the Posterior Fossa. Pediatr Neurosurg 2021; 56:292-299. [PMID: 33873198 DOI: 10.1159/000515033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 02/04/2021] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Arachnoid membranes are well recognized as a cause of cerebrospinal fluid (CSF) flow impairment in disorders such as obstructive hydrocephalus and syringohydromyelia, but can be difficult to detect with standard noninvasive imaging techniques. True fast imaging with steady-state precession (TrueFISP) can exhibit brain pulsations and CSF dynamics with high spatiotemporal resolution. Here, we demonstrate the utility of this technique in the diagnosis and management of arachnoid membranes in the posterior fossa. CASE PRESENTATIONS Three symptomatic children underwent cine TrueFISP imaging for suspicion of CSF membranous obstruction. Whereas standard imaging failed to or did not clearly visualize the site of an obstructive lesion, preoperative TrueFISP identified a membrane in all 3 cases. The membranes were confirmed intraoperatively, and postoperative TrueFISP helped verify adequate marsupialization and recommunication of CSF flow. Two out of the 3 cases showed a decrease in cerebellar tonsillar pulsatility following surgery. All children showed symptomatic improvement. CONCLUSION TrueFISP is able to detect pulsatile arachnoid membranes responsible for CSF outflow obstruction that are otherwise difficult to visualize using standard imaging techniques. We advocate use of this technology in pre- and postsurgical decision-making as it provides a more representative image of posterior fossa pathology and contributes to our understanding of CSF flow dynamics. There is potential to use this technology to establish prognostic biomarkers for disorders of CSF hydrodynamics.
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Affiliation(s)
- Alon Kashanian
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Nader Binesh
- S. Mark Taper Foundation Imaging Center, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Barry D Pressman
- S. Mark Taper Foundation Imaging Center, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Moise Danielpour
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
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15
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Montanino A, Li X, Zhou Z, Zeineh M, Camarillo D, Kleiven S. Subject-specific multiscale analysis of concussion: from macroscopic loads to molecular-level damage. BRAIN MULTIPHYSICS 2021. [DOI: 10.1016/j.brain.2021.100027] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
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16
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Abderezaei J, Martinez J, Terem I, Fabris G, Pionteck A, Yang Y, Holdsworth SJ, Nael K, Kurt M. Amplified Flow Imaging (aFlow): A Novel MRI-Based Tool to Unravel the Coupled Dynamics Between the Human Brain and Cerebrovasculature. IEEE TRANSACTIONS ON MEDICAL IMAGING 2020; 39:4113-4123. [PMID: 32746150 DOI: 10.1109/tmi.2020.3012932] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
With each heartbeat, periodic variations in arterial blood pressure are transmitted along the vasculature, resulting in localized deformations of the arterial wall and its surrounding tissue. Quantification of such motions may help understand various cerebrovascular conditions, yet it has proven technically challenging thus far. We introduce a new image processing algorithm called amplified Flow (aFlow) which allows to study the coupled brain-blood flow motion by combining the amplification of cine and 4D flow MRI. By incorporating a modal analysis technique known as dynamic mode decomposition into the algorithm, aFlow is able to capture the characteristics of transient events present in the brain and arterial wall deformation. Validating aFlow, we tested it on phantom simulations mimicking arterial walls motion and observed that aFlow displays almost twice higher SNR than its predecessor amplified MRI (aMRI). We then applied aFlow to 4D flow and cine MRI datasets of 5 healthy subjects, finding high correlations between blood flow velocity and tissue deformation in selected brain regions, with correlation values r = 0.61 , 0.59, 0.52 for the pons, frontal and occipital lobe ( ). Finally, we explored the potential diagnostic applicability of aFlow by studying intracranial aneurysm dynamics, which seems to be indicative of rupture risk. In two patients, aFlow successfully visualized the imperceptible aneurysm wall motion, additionally quantifying the increase in the high frequency wall displacement after a one-year follow-up period (20%, 76%). These preliminary data suggest that aFlow may provide a novel imaging biomarker for the assessment of aneurysms evolution, with important potential diagnostic implications.
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17
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Dixon B, MacLeod DB. Assessment of a Non Invasive Brain Oximeter in Volunteers Undergoing Acute Hypoxia. MEDICAL DEVICES-EVIDENCE AND RESEARCH 2020; 13:183-194. [PMID: 32669881 PMCID: PMC7335769 DOI: 10.2147/mder.s250102] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 06/09/2020] [Indexed: 12/03/2022] Open
Abstract
INTRODUCTION Research in traumatic brain injury suggests better patient outcomes when invasive oxygen monitoring is used to detect and correct episodes of brain hypoxia. Invasive brain oxygen monitoring is, however, not routinely used due to the risks, costs and technical challengers. We are developing a non-invasive brain oximeter to address these limitations. The monitor uses the principles of pulse oximetry to record a brain photoplethysmographic waveform and oxygen saturations. We undertook a study in volunteers to assess the new monitor. PATIENTS AND METHODS We compared the temporal changes in the brain and skin oxygen saturations in six volunteers undergoing progressive hypoxia to reach arterial saturations of 70%. This approach provides a method to discriminate potential contamination of the brain signal by skin oxygen levels, as the responses in brain and skin oxygen saturations are distinct due to the auto-regulation of cerebral blood flow to compensate for hypoxia. Conventional pulse oximetry was used to assess skin oxygen levels. Blood was also collected from the internal jugular vein and correlated with the brain oximeter oxygen levels. RESULTS At baseline, a photoplethysmographic waveform consistent with that expected from the brain was obtained in five subjects. The signal was adequate to assess oxygen saturations in three subjects. During hypoxia, the brain's oximeter oxygen saturation fell to 74%, while skin saturation fell to 50% (P<0.0001). The brain photoplethysmographic waveform developed a high-frequency oscillation of ~7 Hz, which was not present in the skin during hypoxia. A weak correlation between the brain oximeter and proximal internal jugular vein oxygen levels was demonstrated, R2=0.24, P=0.01. CONCLUSION Brain oximeter oxygen saturations were relatively well preserved compared to the skin during hypoxia. These findings are consistent with the expected physiological responses and suggest skin oxygen levels did not markedly contaminate the brain oximeter signal.
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Affiliation(s)
| | - David B MacLeod
- Human Pharmacology and Physiology Laboratory, Department of Anesthesiology and School of Nursing, Duke University, Durham, NC, USA
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18
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Parsons N, Bowden SC, Vogrin S, D'Souza WJ. Single-subject manual independent component analysis and resting state fMRI connectivity outcomes in patients with juvenile absence epilepsy. Magn Reson Imaging 2019; 66:42-49. [PMID: 31734272 DOI: 10.1016/j.mri.2019.11.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 10/17/2019] [Accepted: 11/09/2019] [Indexed: 12/30/2022]
Abstract
The quality of fMRI data impacts functional connectivity measures and consequently, the decisions that clinicians and researchers make regarding functional connectivity interpretation. The present study used resting state fMRI to investigate resting state network connectivity in a sample of patients with Juvenile Absence Epilepsy. Single-subject manual independent component analysis was used in two levels, whereby all noise components were removed, and cerebrospinal fluid pulsation components only were isolated and removed. Improved temporal signal to noise ratios and functional connectivity metrics were observed in each of the cleaning levels for both epilepsy and control cohorts. Results showed full, single-subject manual independent component analysis reduced the number of functional connectivity correlations and increased the strength of these correlations. Similar effects were also observed for the cerebrospinal fluid pulsation only cleaned data relative to the uncleaned, and fully cleaned data. Single-subject manual independent component analysis coupled with short TR multiband acquisition can significantly improve the validity of findings derived from fMRI data sets.
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Affiliation(s)
- Nicholas Parsons
- Melbourne School of Psychological Sciences, The University of Melbourne, Parkville, VIC 3010, Australia; Department of Clinical Neurosciences, St Vincent's Hospital Melbourne, 41 Victoria Parade, Fitzroy, VIC 3065, Australia.
| | - Stephen C Bowden
- Melbourne School of Psychological Sciences, The University of Melbourne, Parkville, VIC 3010, Australia; Department of Medicine, St Vincent's Hospital, The University of Melbourne, 41 Victoria Parade, Fitzroy, VIC 3065, Australia
| | - Simon Vogrin
- Department of Clinical Neurosciences, St Vincent's Hospital Melbourne, 41 Victoria Parade, Fitzroy, VIC 3065, Australia
| | - Wendyl J D'Souza
- Melbourne School of Psychological Sciences, The University of Melbourne, Parkville, VIC 3010, Australia; Department of Medicine, St Vincent's Hospital, The University of Melbourne, 41 Victoria Parade, Fitzroy, VIC 3065, Australia
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19
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Champagne AA, Peponoulas E, Terem I, Ross A, Tayebi M, Chen Y, Coverdale NS, Nielsen PMF, Wang A, Shim V, Holdsworth SJ, Cook DJ. Novel strain analysis informs about injury susceptibility of the corpus callosum to repeated impacts. Brain Commun 2019; 1:fcz021. [PMID: 32954264 PMCID: PMC7425391 DOI: 10.1093/braincomms/fcz021] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 08/15/2019] [Accepted: 08/21/2019] [Indexed: 01/08/2023] Open
Abstract
Increasing evidence for the cumulative effects of head trauma on structural integrity of the brain has emphasized the need to understand the relationship between tissue mechanic properties and injury susceptibility. Here, diffusion tensor imaging, helmet accelerometers and amplified magnetic resonance imaging were combined to gather insight about the region-specific vulnerability of the corpus callosum to microstructural changes in white-matter integrity upon exposure to sub-concussive impacts. A total of 33 male Canadian football players (meanage = 20.3 ± 1.4 years) were assessed at three time points during a football season (baseline pre-season, mid-season and post-season). The athletes were split into a LOW (N = 16) and HIGH (N = 17) exposure group based on the frequency of sub-concussive impacts sustained on a per-session basis, measured using the helmet-mounted accelerometers. Longitudinal decreases in fractional anisotropy were observed in anterior and posterior regions of the corpus callosum (average cluster size = 40.0 ± 4.4 voxels; P < 0.05, corrected) for athletes from the HIGH exposure group. These results suggest that the white-matter tract may be vulnerable to repetitive sub-concussive collisions sustained over the course of a football season. Using these findings as a basis for further investigation, a novel exploratory analysis of strain derived from sub-voxel motion of brain tissues in response to cardiac impulses was developed using amplified magnetic resonance imaging. This approach revealed specific differences in strain (and thus possibly stiffness) along the white-matter tract (P < 0.0001) suggesting a possible signature relationship between changes in white-matter integrity and tissue mechanical properties. In light of these findings, additional information about the viscoelastic behaviour of white-matter tissues may be imperative in elucidating the mechanisms responsible for region-specific differences in injury susceptibility observed, for instance, through changes in microstructural integrity following exposure to sub-concussive head impacts.
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Affiliation(s)
- Allen A Champagne
- Centre for Neuroscience Studies, Room 260, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Emile Peponoulas
- Centre for Neuroscience Studies, Room 260, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Itamar Terem
- Department of Electrical Engineering, Stanford University, 350 Serra Mall, Stanford, CA, USA
| | | | - Maryam Tayebi
- Auckland Bioengineering Institute, University of Auckland, Auckland Bioengineering House, L6, 70 Symonds Street, Auckland 1010, New Zealand
| | - Yining Chen
- Centre for Neuroscience Studies, Room 260, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Nicole S Coverdale
- Centre for Neuroscience Studies, Room 260, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Poul M F Nielsen
- Auckland Bioengineering Institute, University of Auckland, Auckland Bioengineering House, L6, 70 Symonds Street, Auckland 1010, New Zealand.,Department of Engineering Science, Faculty of Engineering, University of Auckland, Auckland 1010, New Zealand
| | - Alan Wang
- Auckland Bioengineering Institute, University of Auckland, Auckland Bioengineering House, L6, 70 Symonds Street, Auckland 1010, New Zealand
| | - Vickie Shim
- Auckland Bioengineering Institute, University of Auckland, Auckland Bioengineering House, L6, 70 Symonds Street, Auckland 1010, New Zealand
| | - Samantha J Holdsworth
- Department of Anatomy and Medical Imaging & Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, Auckland 1023, New Zealand
| | - Douglas J Cook
- Centre for Neuroscience Studies, Room 260, Queen's University, Kingston, ON K7L 3N6, Canada.,Department of Surgery, Queen's University, Kingston, ON, Canada
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20
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Perrot V, Salles S, Vray D, Liebgott H. Video Magnification Applied in Ultrasound. IEEE Trans Biomed Eng 2019; 66:283-288. [DOI: 10.1109/tbme.2018.2820384] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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21
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Terem I, Ni WW, Goubran M, Rahimi MS, Zaharchuk G, Yeom KW, Moseley ME, Kurt M, Holdsworth SJ. Revealing sub-voxel motions of brain tissue using phase-based amplified MRI (aMRI). Magn Reson Med 2018; 80:2549-2559. [PMID: 29845645 PMCID: PMC6269230 DOI: 10.1002/mrm.27236] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Revised: 03/28/2018] [Accepted: 04/05/2018] [Indexed: 01/15/2023]
Abstract
PURPOSE Amplified magnetic resonance imaging (aMRI) was recently introduced as a new brain motion detection and visualization method. The original aMRI approach used a video-processing algorithm, Eulerian video magnification (EVM), to amplify cardio-ballistic motion in retrospectively cardiac-gated MRI data. Here, we strive to improve aMRI by incorporating a phase-based motion amplification algorithm. METHODS Phase-based aMRI was developed and tested for correct implementation and ability to amplify sub-voxel motions using digital phantom simulations. The image quality of phase-based aMRI was compared with EVM-based aMRI in healthy volunteers at 3T, and its amplified motion characteristics were compared with phase-contrast MRI. Data were also acquired on a patient with Chiari I malformation, and qualitative displacement maps were produced using free form deformation (FFD) of the aMRI output. RESULTS Phantom simulations showed that phase-based aMRI has a linear dependence of amplified displacement on true displacement. Amplification was independent of temporal frequency, varying phantom intensity, Rician noise, and partial volume effect. Phase-based aMRI supported larger amplification factors than EVM-based aMRI and was less sensitive to noise and artifacts. Abnormal biomechanics were seen on FFD maps of the Chiari I malformation patient. CONCLUSION Phase-based aMRI might be used in the future for quantitative analysis of minute changes in brain motion and may reveal subtle physiological variations of the brain as a result of pathology using processing of the fundamental harmonic or by selectively varying temporal harmonics. Preliminary data shows the potential of phase-based aMRI to qualitatively assess abnormal biomechanics in Chiari I malformation.
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Affiliation(s)
- Itamar Terem
- Department of Radiology, Stanford University, Stanford, California
| | - Wendy W Ni
- Department of Radiology, Stanford University, Stanford, California
| | - Maged Goubran
- Department of Radiology, Stanford University, Stanford, California
| | | | - Greg Zaharchuk
- Department of Radiology, Stanford University, Stanford, California
| | - Kristen W Yeom
- Department of Radiology, Stanford University, Stanford, California
| | | | - Mehmet Kurt
- Stevens Institute of Technology, Hoboken, New Jersey
| | - Samantha J Holdsworth
- Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
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22
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Hahn S, Absil J, Debeir O, Metens T. Assessment of cardiac-driven liver movements with filtered harmonic phase image representation, optical flow quantification, and motion amplification. Magn Reson Med 2018; 81:2788-2798. [PMID: 30485536 DOI: 10.1002/mrm.27596] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 09/21/2018] [Accepted: 10/17/2018] [Indexed: 12/28/2022]
Abstract
PURPOSE To characterize cardiac-driven liver movements using a harmonic phase image representation (HARP) with an optical flow quantification and motion amplification method. The method was applied to define the cardiac trigger delay providing minimal signal losses in liver DWI images. METHODS The 16-s breath-hold balanced-SSFP time resolved 20 images/s were acquired at 3T in coronal and sagittal orientations. A peripheral pulse unit signal was recorded. Cardiac-triggered DWI images were acquired after different peripheral pulse unit delays. A steerable pyramid decomposition with multiple orientations and spatial frequencies was applied. The liver motion field-map was derived from temporal variations of the HARP representation filtered around the cardiac frequency. Liver displacements were quantified with an optical flow method; moreover the right liver motion was amplified. RESULTS The largest displacements were observed in the left liver (feet-head:3.70 ± 1.06 mm; anterior-posterior: 2.35 ± 0.51 mm). Displacements were statistically significantly weaker in the middle right liver (0.47 ± 0.11 mm; P = 0.0156). The average error was 0.013 ± 0.022 mm (coronal plane) and 0.021 ± 0.041 mm (sagittal plane). The velocity field demonstrated opposing movements of the right liver extremities during the cardiac cycle. DWI signal loss was minimized in regions and instants of smallest amplitude of both velocity and velocity gradient. CONCLUSION Cardiac-driven liver movements were quantified with combined cardiac frequency-filtered HARP and optical flow methods. A motion phase opposition between right liver extremities was demonstrated. Displacement amplitude and velocity were larger in the left liver especially along the vertical direction. Motion amplification visually emphasized cardiac-driven right liver displacements. The optimal cardiac timing minimizing signal loss in liver DWI images was derived.
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Affiliation(s)
- Stephan Hahn
- LISA - IMAGE: Laboratories of Image, Signal processing and Acoustics, Université Libre de Bruxelles, Brussels, Belgium
| | - Julie Absil
- Department of Radiology- Magnetic Resonance Imaging, Hôpital Erasme, Université Libre de Bruxelles, Brussels, Belgium
| | - Olivier Debeir
- LISA - IMAGE: Laboratories of Image, Signal processing and Acoustics, Université Libre de Bruxelles, Brussels, Belgium
| | - Thierry Metens
- Department of Radiology- Magnetic Resonance Imaging, Hôpital Erasme, Université Libre de Bruxelles, Brussels, Belgium
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