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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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Bergs J, Morr AS, Silva RV, Infante‐Duarte C, Sack I. The Networking Brain: How Extracellular Matrix, Cellular Networks, and Vasculature Shape the In Vivo Mechanical Properties of the Brain. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2402338. [PMID: 38874205 PMCID: PMC11336943 DOI: 10.1002/advs.202402338] [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: 03/04/2024] [Revised: 05/22/2024] [Indexed: 06/15/2024]
Abstract
Mechanically, the brain is characterized by both solid and fluid properties. The resulting unique material behavior fosters proliferation, differentiation, and repair of cellular and vascular networks, and optimally protects them from damaging shear forces. Magnetic resonance elastography (MRE) is a noninvasive imaging technique that maps the mechanical properties of the brain in vivo. MRE studies have shown that abnormal processes such as neuronal degeneration, demyelination, inflammation, and vascular leakage lead to tissue softening. In contrast, neuronal proliferation, cellular network formation, and higher vascular pressure result in brain stiffening. In addition, brain viscosity has been reported to change with normal blood perfusion variability and brain maturation as well as disease conditions such as tumor invasion. In this article, the contributions of the neuronal, glial, extracellular, and vascular networks are discussed to the coarse-grained parameters determined by MRE. This reductionist multi-network model of brain mechanics helps to explain many MRE observations in terms of microanatomical changes and suggests that cerebral viscoelasticity is a suitable imaging marker for brain disease.
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Affiliation(s)
- Judith Bergs
- Department of RadiologyCharité – Universitätsmedizin BerlinCharitéplatz 110117BerlinGermany
| | - Anna S. Morr
- Department of RadiologyCharité – Universitätsmedizin BerlinCharitéplatz 110117BerlinGermany
| | - Rafaela V. Silva
- Experimental and Clinical Research Centera cooperation between the Max Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité – Universitätsmedizin BerlinLindenberger Weg 8013125BerlinGermany
- Corporate Member of Freie Universität Berlin and Humboldt‐Universität zu BerlinECRC Experimental and Clinical Research CenterCharité – Universitätsmedizin BerlinCharitéplatz 110117BerlinGermany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC)Robert‐Rössle‐Straße 1013125BerlinGermany
| | - Carmen Infante‐Duarte
- Experimental and Clinical Research Centera cooperation between the Max Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité – Universitätsmedizin BerlinLindenberger Weg 8013125BerlinGermany
- Corporate Member of Freie Universität Berlin and Humboldt‐Universität zu BerlinECRC Experimental and Clinical Research CenterCharité – Universitätsmedizin BerlinCharitéplatz 110117BerlinGermany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC)Robert‐Rössle‐Straße 1013125BerlinGermany
| | - Ingolf Sack
- Department of RadiologyCharité – Universitätsmedizin BerlinCharitéplatz 110117BerlinGermany
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Baek J, Kumar S, Schaffer DV. Dynamic light-responsive RhoA activity regulates mechanosensitive stem cell fate decision in 3D matrices. BIOMATERIALS ADVANCES 2024; 160:213836. [PMID: 38599042 DOI: 10.1016/j.bioadv.2024.213836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 03/05/2024] [Accepted: 03/19/2024] [Indexed: 04/12/2024]
Abstract
The behavior of stem cells is regulated by mechanical cues in their niche that continuously vary due to extracellular matrix (ECM) remodeling, pulsated mechanical stress exerted by blood flow, and/or cell migration. However, it is still unclear how dynamics of mechanical cues influence stem cell lineage commitment, especially in a 3D microenvironment where mechanosensing differs from that in a 2D microenvironment. In the present study, we investigated how temporally varying mechanical signaling regulates expression of the early growth response 1 gene (Egr1), which we recently discovered to be a 3D matrix-specific mediator of mechanosensitive neural stem cell (NSC) lineage commitment. Specifically, we temporally controlled the activity of Ras homolog family member A (RhoA), which is known to have a central role in mechanotransduction, using our previously developed Arabidopsis thaliana cryptochrome-2-based optoactivation system. Interestingly, pulsed RhoA activation induced Egr1 upregulation in stiff 3D gels only, whereas static light stimulation induced an increase in Egr1 expression across a wide range of 3D gel stiffnesses. Actin assembly inhibition limited Egr1 upregulation upon RhoA activation, implying that RhoA signaling requires an actin-involved process to upregulate Egr1. Consistently, static-light RhoA activation rather than pulsed-light activation restricted neurogenesis in soft gels. Our findings indicate that the dynamics of RhoA activation influence Egr1-mediated stem cell fate within 3D matrices in a matrix stiffness-dependent manner.
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Affiliation(s)
- Jieung Baek
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Bioengineering, University of California, Berkeley, CA 94720, USA; Division of Mechanical and Biomedical Engineering, Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul, 03760, Republic of Korea
| | - Sanjay Kumar
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Bioengineering, University of California, Berkeley, CA 94720, USA.
| | - David V Schaffer
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Bioengineering, University of California, Berkeley, CA 94720, USA; Helen Wills Neuroscience Institute, Berkeley, CA 94720, USA.
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de Zwart JA, van Gelderen P, Wang Y, Duyn JH. Accelerated multislice MRI with patterned excitation. Magn Reson Med 2024; 91:252-265. [PMID: 37769229 PMCID: PMC11342169 DOI: 10.1002/mrm.29850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 08/14/2023] [Accepted: 08/15/2023] [Indexed: 09/30/2023]
Abstract
PURPOSE Accelerate multislice 2D MRI by using RF pulses that simultaneously act on different slices to combine contrast preparation and image acquisition. THEORY AND METHODS MRI applications often require the use of multiple RF pulses to generate desired contrast and prepare the signal for readout. Examples are the use of inversion prepulses to generate T1 contrast, or the use of spin-echo preparations to generate T2 or diffusion contrast. In multislice MRI, this separation of contrast preparation and readout can render scans time-inefficient and lengthy. We introduce a class of pulse sequences that overcomes this inefficiency by combining contrast preparation and signal readout. This is accomplished by using RF pulses that manipulate the magnetization of multiple slices simultaneously and a gradient crusher scheme that selects a target slice for readout. RESULTS Feasibility of the method was demonstrated for spin echo-based measurement of water diffusion and tissue pulsation in human brain at 3 T. Increases in time-efficiency and reductions in scan time were highly dependent on specific implementation and reached as high as 25% and 53%, respectively. CONCLUSION A novel approach to multislice MRI is demonstrated that reduces scan time for specific applications.
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Affiliation(s)
- Jacco A de Zwart
- Advanced MRI section, Laboratory for Functional and Molecular Imaging, National Institute for Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Peter van Gelderen
- Advanced MRI section, Laboratory for Functional and Molecular Imaging, National Institute for Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Yicun Wang
- Advanced MRI section, Laboratory for Functional and Molecular Imaging, National Institute for Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Jeff H Duyn
- Advanced MRI section, Laboratory for Functional and Molecular Imaging, National Institute for Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
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Burman Ingeberg M, Van Houten E, Zwanenburg JJM. Estimating the viscoelastic properties of the human brain at 7 T MRI using intrinsic MRE and nonlinear inversion. Hum Brain Mapp 2023; 44:6575-6591. [PMID: 37909395 PMCID: PMC10681656 DOI: 10.1002/hbm.26524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 10/04/2023] [Accepted: 10/09/2023] [Indexed: 11/03/2023] Open
Abstract
Intrinsic actuation magnetic resonance elastography (MRE) is a phase-contrast MRI technique that allows for in vivo quantification of mechanical properties of the brain by exploiting brain motion that arise naturally due to the cardiac pulse. The mechanical properties of the brain reflect its tissue microstructure, making it a potentially valuable parameter in studying brain disease. The main purpose of this study was to assess the feasibility of reconstructing the viscoelastic properties of the brain using high-quality 7 T MRI displacement measurements, obtained using displacement encoding with stimulated echoes (DENSE) and intrinsic actuation. The repeatability and sensitivity of the method for detecting normal regional variation in brain tissue properties was assessed as secondary goal. The displacement measurements used in this analysis were previously acquired for a separate study, where eight healthy subjects (27 ± 7 years) were imaged with repeated scans (spatial resolution approx. 2 mm isotropic, temporal resolution 75 ms, motion sensitivity 0.35 mm/2π for displacements in anterior-posterior and left-right directions, and 0.7 mm/2π for feet-head displacements). The viscoelastic properties of the brain were estimated using a subzone based non-linear inversion scheme. The results show comparable consistency to that of extrinsic MRE between the viscoelastic property maps obtained from repeated displacement measurements. The shear stiffness maps showed fairly consistent spatial patterns. The whole-brain repeatability coefficient (RC) for shear stiffness was (mean ± standard deviation) 8 ± 8% relative to the mean whole-brain stiffness, and the damping ratio RC was 28 ± 17% relative to the whole-brain damping ratio. The shear stiffness maps showed similar statistically significant regional trends as demonstrated in a publicly available atlas of viscoelastic properties obtained with extrinsic actuation MRE at 50 Hz. The damping ratio maps showed less consistency, likely due to data-model mismatch of describing the brain as a viscoelastic material under low frequencies. While artifacts induced by fluid flow within the brain remain a limitation of the technique in its current state, intrinsic actuation based MRE allow for consistent and repeatable estimation of the mechanical properties of the brain. The method provides enough sensitivity to investigate regional variation in such properties in the normal brain, which is likely sufficient to also investigate pathological changes.
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Mohsenian S, Ibrahimy A, Al Samman MMF, Oshinski JN, Bhadelia RA, Barrow DL, Allen PA, Amini R, Loth F. Association between resistance to cerebrospinal fluid flow and cardiac-induced brain tissue motion for Chiari malformation type I. Neuroradiology 2023; 65:1535-1543. [PMID: 37644163 PMCID: PMC10497658 DOI: 10.1007/s00234-023-03207-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 07/28/2023] [Indexed: 08/31/2023]
Abstract
PURPOSE Chiari malformation type I (CMI) patients have been independently shown to have both increased resistance to cerebrospinal fluid (CSF) flow in the cervical spinal canal and greater cardiac-induced neural tissue motion compared to healthy controls. The goal of this paper is to determine if a relationship exists between CSF flow resistance and brain tissue motion in CMI subjects. METHODS Computational fluid dynamics (CFD) techniques were employed to compute integrated longitudinal impedance (ILI) as a measure of unsteady resistance to CSF flow in the cervical spinal canal in thirty-two CMI subjects and eighteen healthy controls. Neural tissue motion during the cardiac cycle was assessed using displacement encoding with stimulated echoes (DENSE) magnetic resonance imaging (MRI) technique. RESULTS The results demonstrate a positive correlation between resistance to CSF flow and the maximum displacement of the cerebellum for CMI subjects (r = 0.75, p = 6.77 × 10-10) but not for healthy controls. No correlation was found between CSF flow resistance and maximum displacement in the brainstem for CMI or healthy subjects. The magnitude of resistance to CSF flow and maximum cardiac-induced brain tissue motion were not statistically different for CMI subjects with and without the presence of five CMI symptoms: imbalance, vertigo, swallowing difficulties, nausea or vomiting, and hoarseness. CONCLUSION This study establishes a relationship between CSF flow resistance in the cervical spinal canal and cardiac-induced brain tissue motion in the cerebellum for CMI subjects. Further research is necessary to understand the importance of resistance and brain tissue motion in the symptomatology of CMI.
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Affiliation(s)
- Saeed Mohsenian
- Department of Bioengineering, Northeastern University, 360 Huntington Ave, Boston, MA 02115 USA
| | - Alaaddin Ibrahimy
- Department of Biomedical Engineering, Yale University, 17 Hillhouse Ave, New Haven, CT 06520 USA
| | | | - John N. Oshinski
- Departments of Radiology & Imaging Sciences and Biomedical Engineering, Emory University School of Medicine, 1364 Clifton Road NE, Atlanta, GA 30322 USA
| | - Rafeeque A. Bhadelia
- Department of Radiology, Beth Israel Deaconess Medical Center & Harvard University School of Medicine, 330 Brookline Ave, Boston, MA 02215 USA
| | - Daniel L. Barrow
- Department of Neurosurgery, Emory University School of Medicine, 1364 Clifton Road NE, Atlanta, GA 30322 USA
| | - Philip A. Allen
- Department of Psychology, The University of Akron, 302 E Buchtel Ave, Akron, OH 44325 USA
| | - Rouzbeh Amini
- Departments of Mechanical and Industrial Engineering, and Bioengineering, Northeastern University, 805 Columbus Ave, ISEC 508, Boston, MA 02120 USA
| | - Francis Loth
- Departments of Mechanical and Industrial Engineering, and Bioengineering, Northeastern University, 360 Huntington Ave, SN 257, Boston, MA 02115 USA
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Meyer T, Kreft B, Bergs J, Antes E, Anders MS, Wellge B, Braun J, Doyley M, Tzschätzsch H, Sack I. Stiffness pulsation of the human brain detected by non-invasive time-harmonic elastography. Front Bioeng Biotechnol 2023; 11:1140734. [PMID: 37650041 PMCID: PMC10463728 DOI: 10.3389/fbioe.2023.1140734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 07/19/2023] [Indexed: 09/01/2023] Open
Abstract
Introduction: Cerebral pulsation is a vital aspect of cerebral hemodynamics. Changes in arterial pressure in response to cardiac pulsation cause cerebral pulsation, which is related to cerebrovascular compliance and cerebral blood perfusion. Cerebrovascular compliance and blood perfusion influence the mechanical properties of the brain, causing pulsation-induced changes in cerebral stiffness. However, there is currently no imaging technique available that can directly quantify the pulsation of brain stiffness in real time. Methods: Therefore, we developed non-invasive ultrasound time-harmonic elastography (THE) technique for the real-time detection of brain stiffness pulsation. We used state-of-the-art plane-wave imaging for interleaved acquisitions of shear waves at a frequency of 60 Hz to measure stiffness and color flow imaging to measure cerebral blood flow within the middle cerebral artery. In the second experiment, we used cost-effective lineby-line B-mode imaging to measure the same mechanical parameters without flow imaging to facilitate future translation to the clinic. Results: In 10 healthy volunteers, stiffness increased during the passage of the arterial pulse wave from 4.8% ± 1.8% in the temporal parenchyma to 11% ± 5% in the basal cisterns and 13% ± 9% in the brain stem. Brain stiffness peaked in synchrony with cerebral blood flow at approximately 180 ± 30 ms after the cardiac R-wave. Line-by-line THE provided the same stiffness values with similar time resolution as high-end plane-wave THE, demonstrating the robustness of brain stiffness pulsation as an imaging marker. Discussion: Overall, this study sets the background and provides reference values for time-resolved THE in the human brain as a cost-efficient and easy-touse mechanical biomarker associated with cerebrovascular compliance.
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Affiliation(s)
- Tom Meyer
- Department of Radiology, Charité—University Medicine Berlin, Berlin, Germany
| | - Bernhard Kreft
- Department of Radiology, Charité—University Medicine Berlin, Berlin, Germany
| | - Judith Bergs
- Department of Radiology, Charité—University Medicine Berlin, Berlin, Germany
| | - Erik Antes
- Department of Radiology, Charité—University Medicine Berlin, Berlin, Germany
| | - Matthias S. Anders
- Department of Radiology, Charité—University Medicine Berlin, Berlin, Germany
| | - Brunhilde Wellge
- Department of Radiology, Charité—University Medicine Berlin, Berlin, Germany
| | - Jürgen Braun
- Institute of Medical Informatics, Charité—University Medicine Berlin, Berlin, Germany
| | - Marvin Doyley
- Hajim School of Engineering and Applied Sciences, University of Rochester, Rochester, NY, United States
| | - Heiko Tzschätzsch
- Department of Radiology, Charité—University Medicine Berlin, Berlin, Germany
| | - Ingolf Sack
- Department of Radiology, Charité—University Medicine Berlin, Berlin, Germany
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Al Samman MMF, Ibrahimy A, Nwotchouang BST, Oshinski JN, Barrow DL, Allen PA, Amini R, Bhadelia RA, Loth F. The Relationship Between Imbalance Symptom and Cardiac Pulsation Induced Mechanical Strain in the Brainstem and Cerebellum for Chiari Malformation Type I. J Biomech Eng 2023; 145:081005. [PMID: 37295931 PMCID: PMC10782862 DOI: 10.1115/1.4062723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 06/07/2023] [Accepted: 06/07/2023] [Indexed: 06/12/2023]
Abstract
Chiari malformation Type I (CMI) is known to have an altered biomechanical environment for the brainstem and cerebellum; however, it is unclear whether these altered biomechanics play a role in the development of CMI symptoms. We hypothesized that CMI subjects have a higher cardiac-induced strain in specific neurological tracts pertaining to balance, and postural control. We measured displacement over the cardiac cycle using displacement encoding with stimulated echoes magnetic resonance imaging in the cerebellum, brainstem, and spinal cord in 37 CMI subjects and 25 controls. Based on these measurements, we computed strain, translation, and rotation in tracts related to balance. The global strain on all tracts was small (<1%) for CMI subject and controls. Strain was found to be nearly doubled in three tracts for CMI subjects compared to controls (p < 0.03). The maximum translation and rotation were ∼150 μm and ∼1 deg, respectively and 1.5-2 times greater in CMI compared to controls in four tracts (p < 0.005). There was no significant difference between strain, translation, and rotation on the analyzed tracts in CMI subjects with imbalance compared to those without imbalance. A moderate correlation was found between cerebellar tonsillar position and strain on three tracts. The lack of statistically significant difference between strain in CMI subjects with and without imbalance could imply that the magnitude of the observed cardiac-induced strain was too small to cause substantial damage to the tissue (<1%). Activities such as coughing, or Valsalva may produce a greater strain.
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Affiliation(s)
| | - Alaaddin Ibrahimy
- Department of Biomedical Engineering, Yale University, 17 Hillhouse Ave, New Haven, CT 06520
| | | | - John N. Oshinski
- Departments of Radiology & Imaging Sciences and Biomedical Engineering, Emory University School of Medicine, 1364 Clifton Road NE, Atlanta, GA 30322
| | - Daniel L. Barrow
- Department of Neurosurgery, Emory University School of Medicine, 1364 Clifton Road NE, Atlanta, GA 30322
| | - Philip A. Allen
- Department of Psychology, The University of Akron, 302 E Buchtel Ave, Akron, OH 44325
| | - Rouzbeh Amini
- Departments of Mechanical and Industrial Engineering, and Bioengineering, Northeastern University, 805 Columbus Ave, ISEC 508, Boston, MA 02120
| | - Rafeeque A. Bhadelia
- Department of Radiology, Beth Israel Deaconess Medical Center & Harvard University School of Medicine, 330 Brookline Ave, Boston, MA 02215
| | - Francis Loth
- Departments of Mechanical and Industrial Engineering, and Bioengineering, Northeastern University, 360 Huntington Ave, SN 257, Boston, MA 02115
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Sloots JJ, Biessels GJ, Amelink GJ, Zwanenburg JJM. Abnormalities in cardiac-induced brain tissue deformations are now detectable with MRI: A case-report of a patient who underwent craniotomy after trauma. Magn Reson Imaging 2023; 98:62-65. [PMID: 36657534 DOI: 10.1016/j.mri.2023.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 01/06/2023] [Indexed: 01/18/2023]
Abstract
BACKGROUND Heartbeat and respiration induce cyclic brain tissue deformations, which receive increasing attention as potential driving force for brain clearance. These deformations can now be assessed using a novel 3D strain tensor imaging (STI) method at 7 T MRI. METHODS An 18-year-old man had suffered a traumatic brain injury and was treated with a craniotomy with a maximal diameter of 12 cm. STI was employed to capture cardiac-induced brain tissue deformations and additional time-resolved 2D flow measurements were acquired to capture cerebrospinal fluid (CSF) flow towards the spinal canal. RESULTS The craniotomy caused major changes in all aspects of the brain's mechanical dynamics as compared to healthy volunteer references. Tissue strains increased, particularly around the craniotomy, and directionality of deformations showed large abnormalities, also in the contralateral hemisphere. As the brain tissue could pulsate outward from the skull, physiological pulsatile CSF flow at the foramen magnum was abolished. CONCLUSIONS This work illustrates how STI can assess physiological patterns of brain tissue deformation and how craniotomy leads to widespread deformation abnormalities that can be detected at a single patient level. While this case is meant to provide proof of concept, application of STI in other conditions of abnormal brain mechanical dynamics warrants further study.
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Affiliation(s)
- Jacob-Jan Sloots
- Department of Radiology, University Medical Center Utrecht, the Netherlands
| | - Geert Jan Biessels
- Department of Neurology, UMC Utrecht Brain Center, University Medical Center Utrecht, the Netherlands
| | - G Johan Amelink
- Department of Neurosurgery, UMC Utrecht Brain Center, University Medical Center Utrecht, the Netherlands
| | - Jaco J M Zwanenburg
- Department of Radiology, University Medical Center Utrecht, the Netherlands.
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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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11
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Patient-specific computational fluid dynamic simulation of cerebrospinal fluid flow in the intracranial space. Brain Res 2022; 1790:147962. [DOI: 10.1016/j.brainres.2022.147962] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 05/16/2022] [Accepted: 05/31/2022] [Indexed: 11/24/2022]
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12
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Sloots JJ, Froeling M, Biessels GJ, Zwanenburg JJM. Dynamic brain ADC variations over the cardiac cycle and their relation to tissue strain assessed with DENSE at high-field MRI. Magn Reson Med 2022; 88:266-279. [PMID: 35344595 PMCID: PMC9315037 DOI: 10.1002/mrm.29209] [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: 06/28/2021] [Revised: 12/10/2021] [Accepted: 02/08/2022] [Indexed: 12/11/2022]
Abstract
Purpose The ADC of brain tissue slightly varies over the cardiac cycle. This variation could reflect physiology, including mixing of the interstitial fluid, relevant for brain waste clearance. However, it is known from cardiac diffusion imaging that tissue deformation by itself affects the magnitude of the MRI signal, leading to artificial ADC variations as well. This study investigates to what extent tissue deformation causes artificial ADC variations in the brain. Theory and Methods We implemented a high‐field MRI sequence with stimulated echo acquisition mode that simultaneously measures brain tissue deformation and ADC. Based on the measured tissue deformation, we simulated the artificial ADC variation by combining established theoretical frameworks and compared the results with the measured ADC variation. We acquired data in 8 healthy volunteers with diffusion weighting b = 300 and b = 1000 s/mm2. Results Apparent diffusion coefficient variation was largest in the feet‐to‐head direction and showed the largest deviation from the mean ADC at peak systole. Artificial ADC variation estimated from tissue deformation was 1.3 ± 0.37·10−5 mm2/s in the feet‐to‐head direction for gray matter, and 0.75 ± 0.29·10−5 mm2/s for white matter. The measured ADC variation in the feet‐to‐head direction was 5.6·10−5 ± 1.5·10−5 mm2/s for gray matter and 3.2·10−5 ± 1.0·10−5 mm2/s for white matter, which was a factor of 3.5 ± 0.82 and 3.4 ± 0.57 larger than the artificial diffusion variations. The measured diffusion variations in the right‐to‐left/anterior‐to‐posterior direction were a factor of 1.5 ± 1.0/1.7 ± 1.4 and 2.0 ± 0.91/2.5 ± 0.94 larger than the artificial diffusion variations for gray matter and white matter, respectively. Conclusion Apparent diffusion coefficient variations in the brain likely largely reflect physiology.
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Affiliation(s)
- Jacob-Jan Sloots
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Martijn Froeling
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Geert Jan Biessels
- Department of Neurology, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jaco J M Zwanenburg
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
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13
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Bhogal AA. Medullary vein architecture modulates the white matter BOLD cerebrovascular reactivity signal response to CO 2: Observations from high-resolution T2* weighted imaging at 7T. Neuroimage 2021; 245:118771. [PMID: 34861395 DOI: 10.1016/j.neuroimage.2021.118771] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 10/13/2021] [Accepted: 11/29/2021] [Indexed: 01/24/2023] Open
Abstract
Brain stress testing using blood oxygenation level-dependent (BOLD) MRI to evaluate changes in cerebrovascular reactivity (CVR) is of growing interest for evaluating white matter integrity. However, even under healthy conditions, the white matter BOLD-CVR response differs notably from that observed in the gray matter. In addition to actual arterial vascular control, the venous draining topology may influence the WM-CVR response leading to signal delays and dispersions. These types of alterations in hemodynamic parameters are sometimes linked with pathology, but may also arise from differences in normal venous architecture. In this work, high-resolution T2*weighted anatomical images combined with BOLD imaging during a hypercapnic breathing protocol were acquired using a 7 tesla MRI system. Hemodynamic parameters including base CVR, hemodynamic lag, lag-corrected CVR, response onset and signal dispersion, and finally ΔCVR (corrected CVR minus base CVR) were calculated in 8 subjects. Parameter maps were spatially normalized and correlated against an MNI-registered white matter medullary vein atlas. Moderate correlations (Pearson's rho) were observed between medullary vessel frequency (MVF) and ΔCVR (0.52; 0.58 for total WM), MVF and hemodynamic lag (0.42; 0.54 for total WM), MVF and signal dispersion (0.44; 0.53 for total WM), and finally MVF and signal onset (0.43; 0.52 for total WM). Results indicate that, when assessed in the context of the WM venous architecture, changes in the response shape may only be partially reflective of the actual vascular reactivity response occurring further upstream by control vessels. This finding may have implications when attributing diseases mechanisms and/or progression to presumed impaired WM BOLD-CVR.
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Affiliation(s)
- Alex A Bhogal
- Radiology, University Medical Center Utrecht, Heidelberglaan 100, , Utrecht 3584 CX, the Netherland.
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14
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Zoraghi M, Scherf N, Jaeger C, Sack I, Hirsch S, Hetzer S, Weiskopf N. Simulating Local Deformations in the Human Cortex Due to Blood Flow-Induced Changes in Mechanical Tissue Properties: Impact on Functional Magnetic Resonance Imaging. Front Neurosci 2021; 15:722366. [PMID: 34621151 PMCID: PMC8490675 DOI: 10.3389/fnins.2021.722366] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 08/23/2021] [Indexed: 01/06/2023] Open
Abstract
Investigating human brain tissue is challenging due to the complexity and the manifold interactions between structures across different scales. Increasing evidence suggests that brain function and microstructural features including biomechanical features are related. More importantly, the relationship between tissue mechanics and its influence on brain imaging results remains poorly understood. As an important example, the study of the brain tissue response to blood flow could have important theoretical and experimental consequences for functional magnetic resonance imaging (fMRI) at high spatial resolutions. Computational simulations, using realistic mechanical models can predict and characterize the brain tissue behavior and give us insights into the consequent potential biases or limitations of in vivo, high-resolution fMRI. In this manuscript, we used a two dimensional biomechanical simulation of an exemplary human gyrus to investigate the relationship between mechanical tissue properties and the respective changes induced by focal blood flow changes. The model is based on the changes in the brain’s stiffness and volume due to the vasodilation evoked by neural activity. Modeling an exemplary gyrus from a brain atlas we assessed the influence of different potential mechanisms: (i) a local increase in tissue stiffness (at the level of a single anatomical layer), (ii) an increase in local volume, and (iii) a combination of both effects. Our simulation results showed considerable tissue displacement because of these temporary changes in mechanical properties. We found that the local volume increase causes more deformation and consequently higher displacement of the gyrus. These displacements introduced considerable artifacts in our simulated fMRI measurements. Our results underline the necessity to consider and characterize the tissue displacement which could be responsible for fMRI artifacts.
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Affiliation(s)
- Mahsa Zoraghi
- Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Nico Scherf
- Methods and Development Group Neural Data Science and Statistical Computing, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.,Institute for Medical Informatics and Biometry, Carl Gustav Carus Faculty of Medicine, TU Dresden, Dresden, Germany
| | - Carsten Jaeger
- Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Ingolf Sack
- Department of Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Sebastian Hirsch
- Berlin Center for Advanced Neuroimaging, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Berlin Center for Computational Neuroscience, Berlin, Germany
| | - Stefan Hetzer
- Berlin Center for Advanced Neuroimaging, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Berlin Center for Computational Neuroscience, Berlin, Germany
| | - Nikolaus Weiskopf
- Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.,Faculty of Physics and Earth Sciences, Felix Bloch Institute for Solid State Physics, Leipzig University, Leipzig, Germany
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15
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Eppelheimer MS, Nwotchouang BST, Pahlavian SH, Barrow JW, Barrow DL, Amini R, Allen PA, Loth F, Oshinski JN. Cerebellar and Brainstem Displacement Measured with DENSE MRI in Chiari Malformation Following Posterior Fossa Decompression Surgery. Radiology 2021; 301:187-194. [PMID: 34313469 DOI: 10.1148/radiol.2021203036] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Background Posterior fossa decompression (PFD) surgery is a treatment for Chiari malformation type I (CMI). The goals of surgery are to reduce cerebellar tonsillar crowding and restore posterior cerebral spinal fluid flow, but regional tissue biomechanics may also change. MRI-based displacement encoding with stimulated echoes (DENSE) can be used to assess neural tissue displacement. Purpose To assess neural tissue displacement by using DENSE MRI in participants with CMI before and after PFD surgery and examine associations between tissue displacement and symptoms. Materials and Methods In a prospective, HIPAA-compliant study of patients with CMI, midsagittal DENSE MRI was performed before and after PFD surgery between January 2017 and June 2020. Peak tissue displacement over the cardiac cycle was quantified in the cerebellum and brainstem, averaged over each structure, and compared before and after surgery. Paired t tests and nonparametric Wilcoxon signed-rank tests were used to identify surgical changes in displacement, and Spearman correlations were determined between tissue displacement and presurgery symptoms. Results Twenty-three participants were included (mean age ± standard deviation, 37 years ± 10; 19 women). Spatially averaged (mean) peak tissue displacement demonstrated reductions of 46% (79/171 µm) within the cerebellum and 22% (46/210 µm) within the brainstem after surgery (P < .001). Maximum peak displacement, calculated within a circular 30-mm2 area, decreased by 64% (274/427 µm) in the cerebellum and 33% (100/300 µm) in the brainstem (P < .001). No significant associations were identified between tissue displacement and CMI symptoms (r < .74 and P > .012 for all; Bonferroni-corrected P = .0002). Conclusion Neural tissue displacement was reduced after posterior fossa decompression surgery, indicating that surgical intervention changes brain tissue biomechanics. For participants with Chiari malformation type I, no relationship was identified between presurgery tissue displacement and presurgical symptoms. © RSNA, 2021 Online supplemental material is available for this article.
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Affiliation(s)
- Maggie S Eppelheimer
- From the Conquer Chiari Research Center, Departments of Biomedical Engineering (M.S.E., B.S.T.N., F.L.) and Psychology (P.A.A.), University of Akron, 264 Wolf Ledges Pkwy, #211B, Akron, OH 44325; Laboratory of FMRI Technology (LOFT), USC Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, Calif (S.H.P.); Mercer University School of Medicine, Savannah, Ga (J.W.B.); Departments of Neurosurgery (D.L.B.), Radiology (J.N.O.), and Imaging Sciences and Biomedical Engineering (J.N.O.), Emory University, Atlanta, Ga; and Department of Mechanical and Industrial Engineering, Department of Bioengineering, Northeastern University, Boston, Mass (R.A.)
| | - Blaise Simplice Talla Nwotchouang
- From the Conquer Chiari Research Center, Departments of Biomedical Engineering (M.S.E., B.S.T.N., F.L.) and Psychology (P.A.A.), University of Akron, 264 Wolf Ledges Pkwy, #211B, Akron, OH 44325; Laboratory of FMRI Technology (LOFT), USC Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, Calif (S.H.P.); Mercer University School of Medicine, Savannah, Ga (J.W.B.); Departments of Neurosurgery (D.L.B.), Radiology (J.N.O.), and Imaging Sciences and Biomedical Engineering (J.N.O.), Emory University, Atlanta, Ga; and Department of Mechanical and Industrial Engineering, Department of Bioengineering, Northeastern University, Boston, Mass (R.A.)
| | - Soroush Heidari Pahlavian
- From the Conquer Chiari Research Center, Departments of Biomedical Engineering (M.S.E., B.S.T.N., F.L.) and Psychology (P.A.A.), University of Akron, 264 Wolf Ledges Pkwy, #211B, Akron, OH 44325; Laboratory of FMRI Technology (LOFT), USC Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, Calif (S.H.P.); Mercer University School of Medicine, Savannah, Ga (J.W.B.); Departments of Neurosurgery (D.L.B.), Radiology (J.N.O.), and Imaging Sciences and Biomedical Engineering (J.N.O.), Emory University, Atlanta, Ga; and Department of Mechanical and Industrial Engineering, Department of Bioengineering, Northeastern University, Boston, Mass (R.A.)
| | - Jack W Barrow
- From the Conquer Chiari Research Center, Departments of Biomedical Engineering (M.S.E., B.S.T.N., F.L.) and Psychology (P.A.A.), University of Akron, 264 Wolf Ledges Pkwy, #211B, Akron, OH 44325; Laboratory of FMRI Technology (LOFT), USC Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, Calif (S.H.P.); Mercer University School of Medicine, Savannah, Ga (J.W.B.); Departments of Neurosurgery (D.L.B.), Radiology (J.N.O.), and Imaging Sciences and Biomedical Engineering (J.N.O.), Emory University, Atlanta, Ga; and Department of Mechanical and Industrial Engineering, Department of Bioengineering, Northeastern University, Boston, Mass (R.A.)
| | - Daniel L Barrow
- From the Conquer Chiari Research Center, Departments of Biomedical Engineering (M.S.E., B.S.T.N., F.L.) and Psychology (P.A.A.), University of Akron, 264 Wolf Ledges Pkwy, #211B, Akron, OH 44325; Laboratory of FMRI Technology (LOFT), USC Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, Calif (S.H.P.); Mercer University School of Medicine, Savannah, Ga (J.W.B.); Departments of Neurosurgery (D.L.B.), Radiology (J.N.O.), and Imaging Sciences and Biomedical Engineering (J.N.O.), Emory University, Atlanta, Ga; and Department of Mechanical and Industrial Engineering, Department of Bioengineering, Northeastern University, Boston, Mass (R.A.)
| | - Rouzbeh Amini
- From the Conquer Chiari Research Center, Departments of Biomedical Engineering (M.S.E., B.S.T.N., F.L.) and Psychology (P.A.A.), University of Akron, 264 Wolf Ledges Pkwy, #211B, Akron, OH 44325; Laboratory of FMRI Technology (LOFT), USC Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, Calif (S.H.P.); Mercer University School of Medicine, Savannah, Ga (J.W.B.); Departments of Neurosurgery (D.L.B.), Radiology (J.N.O.), and Imaging Sciences and Biomedical Engineering (J.N.O.), Emory University, Atlanta, Ga; and Department of Mechanical and Industrial Engineering, Department of Bioengineering, Northeastern University, Boston, Mass (R.A.)
| | - Philip A Allen
- From the Conquer Chiari Research Center, Departments of Biomedical Engineering (M.S.E., B.S.T.N., F.L.) and Psychology (P.A.A.), University of Akron, 264 Wolf Ledges Pkwy, #211B, Akron, OH 44325; Laboratory of FMRI Technology (LOFT), USC Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, Calif (S.H.P.); Mercer University School of Medicine, Savannah, Ga (J.W.B.); Departments of Neurosurgery (D.L.B.), Radiology (J.N.O.), and Imaging Sciences and Biomedical Engineering (J.N.O.), Emory University, Atlanta, Ga; and Department of Mechanical and Industrial Engineering, Department of Bioengineering, Northeastern University, Boston, Mass (R.A.)
| | - Francis Loth
- From the Conquer Chiari Research Center, Departments of Biomedical Engineering (M.S.E., B.S.T.N., F.L.) and Psychology (P.A.A.), University of Akron, 264 Wolf Ledges Pkwy, #211B, Akron, OH 44325; Laboratory of FMRI Technology (LOFT), USC Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, Calif (S.H.P.); Mercer University School of Medicine, Savannah, Ga (J.W.B.); Departments of Neurosurgery (D.L.B.), Radiology (J.N.O.), and Imaging Sciences and Biomedical Engineering (J.N.O.), Emory University, Atlanta, Ga; and Department of Mechanical and Industrial Engineering, Department of Bioengineering, Northeastern University, Boston, Mass (R.A.)
| | - John N Oshinski
- From the Conquer Chiari Research Center, Departments of Biomedical Engineering (M.S.E., B.S.T.N., F.L.) and Psychology (P.A.A.), University of Akron, 264 Wolf Ledges Pkwy, #211B, Akron, OH 44325; Laboratory of FMRI Technology (LOFT), USC Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, Calif (S.H.P.); Mercer University School of Medicine, Savannah, Ga (J.W.B.); Departments of Neurosurgery (D.L.B.), Radiology (J.N.O.), and Imaging Sciences and Biomedical Engineering (J.N.O.), Emory University, Atlanta, Ga; and Department of Mechanical and Industrial Engineering, Department of Bioengineering, Northeastern University, Boston, Mass (R.A.)
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16
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Nwotchouang BST, Eppelheimer MS, Pahlavian SH, Barrow JW, Barrow DL, Qiu D, Allen PA, Oshinski JN, Amini R, Loth F. Regional Brain Tissue Displacement and Strain is Elevated in Subjects with Chiari Malformation Type I Compared to Healthy Controls: A Study Using DENSE MRI. Ann Biomed Eng 2021; 49:1462-1476. [PMID: 33398617 PMCID: PMC8482962 DOI: 10.1007/s10439-020-02695-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 11/17/2020] [Indexed: 12/26/2022]
Abstract
While the degree of cerebellar tonsillar descent is considered the primary radiologic marker of Chiari malformation type I (CMI), biomechanical forces acting on the brain tissue in CMI subjects are less studied and poorly understood. In this study, regional brain tissue displacement and principal strains in 43 CMI subjects and 25 controls were quantified using a magnetic resonance imaging (MRI) methodology known as displacement encoding with stimulated echoes (DENSE). Measurements from MRI were obtained for seven different brain regions-the brainstem, cerebellum, cingulate gyrus, corpus callosum, frontal lobe, occipital lobe, and parietal lobe. Mean displacements in the cerebellum and brainstem were found to be 106 and 64% higher, respectively, for CMI subjects than controls (p < .001). Mean compression and extension strains in the cerebellum were 52 and 50% higher, respectively, in CMI subjects (p < .001). Brainstem mean extension strain was 41% higher in CMI subjects (p < .001), but no significant difference in compression strain was observed. The other brain structures revealed no significant differences between CMI and controls. These findings demonstrate that brain tissue displacement and strain in the cerebellum and brainstem might represent two new biomarkers to distinguish between CMI subjects and controls.
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Affiliation(s)
| | - Maggie S Eppelheimer
- Conquer Chiari Research Center, Department of Biomedical Engineering, The University of Akron, Akron, OH, 44325-3903, USA
| | | | - Jack W Barrow
- Department of Radiology, University of Tennessee, Knoxville, TN, USA
| | - Daniel L Barrow
- Department of Neurosurgery, Emory University, Atlanta, GA, USA
| | - Deqiang Qiu
- Radiology & Imaging Sciences and Biomedical Engineering, Emory University School of Medicine, Atlanta, USA
| | - Philip A Allen
- Conquer Chiari Research Center, Department of Psychology, The University of Akron, Akron, OH, USA
| | - John N Oshinski
- Radiology & Imaging Sciences and Biomedical Engineering, Emory University School of Medicine, Atlanta, USA
| | - Rouzbeh Amini
- Department of Mechanical and Industrial Engineering, Department of Bioengineering, Northeastern University, Boston, MA, USA
| | - Francis Loth
- Conquer Chiari Research Center, Department of Biomedical Engineering, The University of Akron, Akron, OH, 44325-3903, USA
- Department of Mechanical Engineering, The University of Akron, Akron, OH, USA
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17
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Cortical thinning is associated with brain pulsatility in older adults: An MRI and NIRS study. Neurobiol Aging 2021; 106:103-118. [PMID: 34274697 DOI: 10.1016/j.neurobiolaging.2021.05.002] [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: 03/24/2020] [Revised: 03/29/2021] [Accepted: 05/03/2021] [Indexed: 11/21/2022]
Abstract
Aging is accompanied by global brain atrophy occurring unequally across the brain. Cortical thinning is seen with aging with a larger loss in the frontal and temporal subregions. We explored the link between regional cortical thickness and regional cerebral pulsatility. Sixty healthy individuals were divided into two age groups, young (aged 19-31) and older (aged 65-75) adults. Each participant underwent a near-infrared spectroscopy (NIRS) scan to index regional brain pulsatility from cerebral pulse-transit-time-to-the peak-of-the-pulse (PTTp), an anatomical magnetic resonance imaging (MRI) and a phase-contrast MRI (PC-MRI) scan to measure arterial and cerebrospinal fluid (CSF) pulsatility. In older adults, the greatest association between cerebral pulsatility and cortical thickness was found in superior and middle temporal and superior, middle and inferior frontal areas, which are the regions perfused first by the internal carotid arteries. This association dropped in the postcentral and superior parietal regions. These findings suggest higher brain pulsatility as a potential risk factor contributing to cortical thinning for some brain regions more than others.
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18
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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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19
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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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20
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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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21
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Nwotchouang BST, Eppelheimer MS, Biswas D, Pahlavian SH, Zhong X, Oshinski JN, Barrow DL, Amini R, Loth F. Accuracy of cardiac-induced brain motion measurement using displacement-encoding with stimulated echoes (DENSE) magnetic resonance imaging (MRI): A phantom study. Magn Reson Med 2020; 85:1237-1247. [PMID: 32869349 DOI: 10.1002/mrm.28490] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 07/07/2020] [Accepted: 08/02/2020] [Indexed: 12/12/2022]
Abstract
PURPOSE The goal of this study was to determine the accuracy of displacement-encoding with stimulated echoes (DENSE) MRI in a tissue motion phantom with displacements representative of those observed in human brain tissue. METHODS The phantom was comprised of a plastic shaft rotated at a constant speed. The rotational motion was converted to a vertical displacement through a camshaft. The phantom generated repeatable cyclical displacement waveforms with a peak displacement ranging from 92 µm to 1.04 mm at 1-Hz frequency. The surface displacement of the tissue was obtained using a laser Doppler vibrometer (LDV) before and after the DENSE MRI scans to check for repeatability. The accuracy of DENSE MRI displacement was assessed by comparing the laser Doppler vibrometer and DENSE MRI waveforms. RESULTS Laser Doppler vibrometer measurements of the tissue motion demonstrated excellent cycle-to-cycle repeatability with a maximum root mean square error of 9 µm between the ensemble-averaged displacement waveform and the individual waveforms over 180 cycles. The maximum difference between DENSE MRI and the laser Doppler vibrometer waveforms ranged from 15 to 50 µm. Additionally, the peak-to-peak difference between the 2 waveforms ranged from 1 to 18 µm. CONCLUSION Using a tissue phantom undergoing cyclical motion, we demonstrated the percent accuracy of DENSE MRI to measure displacement similar to that observed for in vivo cardiac-induced brain tissue.
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Affiliation(s)
| | - Maggie S Eppelheimer
- Conquer Chiari Research Center, Department of Biomedical Engineering, The University of Akron, Akron, Ohio, USA
| | - Dipankar Biswas
- Fluids and Structure (FaST) Laboratory, Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, Florida, USA
| | - Soroush Heidari Pahlavian
- Laboratory of FMRI Technology (LOFT), USC Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, California, USA
| | | | - John N Oshinski
- Radiology & Imaging Sciences and Biomedical Engineering, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Daniel L Barrow
- Department of Neurosurgery, Emory University, Atlanta, Georgia, USA
| | - Rouzbeh Amini
- Department of Mechanical and Industrial Engineering, Department of Bioengineering, Northeastern University, Boston, Massachusetts, USA
| | - Francis Loth
- Conquer Chiari Research Center, Department of Biomedical Engineering, The University of Akron, Akron, Ohio, USA.,Department of Mechanical Engineering, The University of Akron, Akron, Ohio, USA
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22
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Schrank F, Warmuth C, Tzschätzsch H, Kreft B, Hirsch S, Braun J, Elgeti T, Sack I. Cardiac-gated steady-state multifrequency magnetic resonance elastography of the brain: Effect of cerebral arterial pulsation on brain viscoelasticity. J Cereb Blood Flow Metab 2020; 40:991-1001. [PMID: 31142226 PMCID: PMC7181097 DOI: 10.1177/0271678x19850936] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 03/29/2019] [Accepted: 04/22/2019] [Indexed: 12/12/2022]
Abstract
In-vivo brain viscoelasticity measured by magnetic resonance elastography (MRE) is a sensitive imaging marker for long-term biophysical changes in brain tissue due to aging and disease; however, it is still unknown whether MRE can reveal short-term periodic alterations of brain viscoelasticity related to cerebral arterial pulsation (CAP). We developed cardiac-gated steady-state MRE (ssMRE) with spiral readout and stroboscopic sampling of continuously induced mechanical vibrations in the brain at 20, 31.25, and 40 Hz frequencies. Maps of magnitude |G*| and phase ϕ of the complex shear modulus were generated by multifrequency dual visco-elasto inversion with a temporal resolution of 40 ms over 4 s. The method was tested in 12 healthy volunteers. During cerebral systole, |G*| decreased by 6.6 ± 1.9% (56 ± 22 Pa, p < 0.001, mean ± SD), whereas ϕ increased by 0.5 ± 0.5% (0.006 ± 0.005 rad, p = 0.002). The effect size of CAP-induced softening slightly decreased with age by 0.10 ± 0.05% per year (p = 0.04), indicating lower cerebral vascular compliance in older individuals. Our data show for the first time that the brain softens and becomes more viscous during systole, possibly due to an effect of CAP-induced arterial expansion and increased blood volume on effective-medium tissue properties. This sensitivity to vascular-solid tissue interactions makes ssMRE potentially useful for detection of cerebral vascular disease.
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Affiliation(s)
- Felix Schrank
- Department of Radiology, Charité –
Universitätsmedizin Berlin, Berlin, Germany
| | - Carsten Warmuth
- Department of Radiology, Charité –
Universitätsmedizin Berlin, Berlin, Germany
| | - Heiko Tzschätzsch
- Department of Radiology, Charité –
Universitätsmedizin Berlin, Berlin, Germany
| | - Bernhard Kreft
- Department of Radiology, Charité –
Universitätsmedizin Berlin, Berlin, Germany
| | - Sebastian Hirsch
- Berlin Center for Advanced Neuroimaging,
Charité – Universitätsmedizin, Berlin, Germany
| | - Jürgen Braun
- Institute of Medical Informatics,
Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Thomas Elgeti
- Department of Radiology, Charité –
Universitätsmedizin Berlin, Berlin, Germany
| | - Ingolf Sack
- Department of Radiology, Charité –
Universitätsmedizin Berlin, Berlin, Germany
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23
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Sloots JJ, Biessels GJ, Zwanenburg JJM. Cardiac and respiration-induced brain deformations in humans quantified with high-field MRI. Neuroimage 2020; 210:116581. [PMID: 31982580 DOI: 10.1016/j.neuroimage.2020.116581] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 12/23/2019] [Accepted: 01/20/2020] [Indexed: 01/20/2023] Open
Abstract
Microvascular blood volume pulsations due to the cardiac and respiratory cycles induce brain tissue deformation and, as such, are considered to drive the brain's waste clearance system. We have developed a high-field magnetic resonance imaging (MRI) technique to quantify both cardiac and respiration-induced tissue deformations, which could not be assessed noninvasively before. The technique acquires motion encoded snapshot images in which various forms of motion and confounders are entangled. First, we optimized the motion sensitivity for application in the human brain. Next, we isolated the heartbeat and respiration-related deformations, by introducing a linear model that fits the snapshot series to the recorded physiological information. As a result, we obtained maps of the physiological tissue deformation with 3mm isotropic spatial resolution. Heartbeat and respiration-induced volumetric strain were significantly different from zero in the basal ganglia (median (25-75% interquartile range): 0.85·10-3 (0.39·10-3-1.05·10-3), p = 0.0008 and -0.28·10-3 (-0.41·10-3-0.06·10-3), p = 0.047, respectively. Smaller volumetric strains were observed in the white matter of the centrum semi ovale (0.28·10-3 (0-0.59·10-3) and -0.06·10-3 (-0.17·10-3-0.20·10-3)), which was only significant for the heartbeat (p = 0.02 and p = 0.7, respectively). Furthermore, heartbeat-induced volumetric strain was about three times larger than respiration-induced volumetric strain. This technique opens a window on the driving forces of the human brain clearance system.
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24
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Adams AL, Viergever MA, Luijten PR, Zwanenburg JJM. Validating faster DENSE measurements of cardiac-induced brain tissue expansion as a potential tool for investigating cerebral microvascular pulsations. Neuroimage 2019; 208:116466. [PMID: 31843712 DOI: 10.1016/j.neuroimage.2019.116466] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 12/13/2019] [Indexed: 11/17/2022] Open
Abstract
Displacement Encoding with Stimulated Echoes (DENSE) has recently shown potential for measuring cardiac-induced cerebral volumetric strain in the human brain. As such, it may provide a powerful tool for investigating the cerebral small vessels. However, further development and validation are necessary. This study aims, first, to validate a retrospectively-gated implementation of the DENSE method for assessing brain tissue pulsations as a physiological marker, and second, to use the acquired measurements to explore intracranial volume dynamics. We acquired repeated measurements of cerebral volumetric strain in 8 healthy subjects, and internally validated these measurements by comparing them to spinal CSF stroke volumes obtained in the same scan session. Peak volumetric strain was found to be highly repeatable between scan sessions. First/second measured peak volumetric strains were: (6.4 ± 1.7)x10-4/(6.7 ± 1.6)x10-4 for whole brain, (9.5 ± 2.5)x10-4/(9.6 ± 2.4)x10-4 for grey matter, and (4.4 ± 1.7)x10-4/(4.1 ± 0.8)x10-4 for white matter. Grey matter showed significantly higher peak strain (p < 0.001) and earlier time-to-peak strain (p < 0.02) than white matter. An approximately linear relationship was found between CSF and brain tissue volume pulsations over the cardiac cycle (mean slope and R2 of 0.88 ± 0.23 and 0.89 ± 0.07, respectively). The close similarity between CSF and brain tissue volume pulsations implies limited contributions from large intracranial vessel pulsations, providing further evidence for venous compression as an additional mechanism for maintaining stable intracranial pressures over the cardiac cycle. Cerebral pulsatility showed consistent inter-subject peak values in healthy subjects, and was strongly correlated to CSF stroke volumes. These results strengthen the potential of brain tissue volumetric strain as a means for investigating the intracranial dynamics of the ageing brain in normal or diseased states.
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Affiliation(s)
- Ayodeji L Adams
- Department of Radiology, University Medical Center Utrecht, E 01.132, Heidelberglaan 100, 3584 CX, Utrecht, the Netherlands.
| | - Max A Viergever
- Image Sciences Institute, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, the Netherlands.
| | - Peter R Luijten
- Department of Radiology, University Medical Center Utrecht, E 01.132, Heidelberglaan 100, 3584 CX, Utrecht, the Netherlands.
| | - Jaco J M Zwanenburg
- Department of Radiology, University Medical Center Utrecht, E 01.132, Heidelberglaan 100, 3584 CX, Utrecht, the Netherlands.
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25
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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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