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Taylor EN, Huang N, Lin S, Mortazavi F, Wedeen VJ, Siamwala JH, Gilbert RJ, Hamilton JA. Lipid and smooth muscle architectural pathology in the rabbit atherosclerotic vessel wall using Q-space cardiovascular magnetic resonance. J Cardiovasc Magn Reson 2022; 24:74. [PMID: 36544161 PMCID: PMC9773609 DOI: 10.1186/s12968-022-00897-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 10/19/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Atherosclerosis is an arterial vessel wall disease characterized by slow, progressive lipid accumulation, smooth muscle disorganization, and inflammatory infiltration. Atherosclerosis often remains subclinical until extensive inflammatory injury promotes vulnerability of the atherosclerotic plaque to rupture with luminal thrombosis, which can cause the acute event of myocardial infarction or stroke. Current bioimaging techniques are unable to capture the pathognomonic distribution of cellular elements of the plaque and thus cannot accurately define its structural disorganization. METHODS We applied cardiovascular magnetic resonance spectroscopy (CMRS) and diffusion weighted CMR (DWI) with generalized Q-space imaging (GQI) analysis to architecturally define features of atheroma and correlated these to the microscopic distribution of vascular smooth muscle cells (SMC), immune cells, extracellular matrix (ECM) fibers, thrombus, and cholesteryl esters (CE). We compared rabbits with normal chow diet and cholesterol-fed rabbits with endothelial balloon injury, which accelerates atherosclerosis and produces advanced rupture-prone plaques, in a well-validated rabbit model of human atherosclerosis. RESULTS Our methods revealed new structural properties of advanced atherosclerosis incorporating SMC and lipid distributions. GQI with tractography portrayed the locations of these components across the atherosclerotic vessel wall and differentiated multi-level organization of normal, pro-inflammatory cellular phenotypes, or thrombus. Moreover, the locations of CE were differentiated from cellular constituents by their higher restrictive diffusion properties, which permitted chemical confirmation of CE by high field voxel-guided CMRS. CONCLUSIONS GQI with tractography is a new method for atherosclerosis imaging that defines a pathological architectural signature for the atheromatous plaque composed of distributed SMC, ECM, inflammatory cells, and thrombus and lipid. This provides a detailed transmural map of normal and inflamed vessel walls in the setting of atherosclerosis that has not been previously achieved using traditional CMR techniques. Although this is an ex-vivo study, detection of micro and mesoscale level vascular destabilization as enabled by GQI with tractography could increase the accuracy of diagnosis and assessment of treatment outcomes in individuals with atherosclerosis.
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Affiliation(s)
- Erik N Taylor
- Department of Physiology & Biophysics, Boston University School of Medicine, Boston, MA, USA
- Department of Radiology, UNM School of Medicine, The University of New Mexico, Albuquerque, NM, USA
| | - Nasi Huang
- Department of Physiology & Biophysics, Boston University School of Medicine, Boston, MA, USA
| | - Sunni Lin
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Farzad Mortazavi
- Department of Anatomy & Neurobiology, Boston University School of Medicine, Boston, MA, USA
| | - Van J Wedeen
- AA Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Jamila H Siamwala
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Richard J Gilbert
- Research Service, Providence VA Medical Center and Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - James A Hamilton
- Department of Physiology & Biophysics, Boston University School of Medicine, Boston, MA, USA.
- Department of Biomedical Engineering, Boston University, Boston, MA, USA.
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Liang X, Elsaid NMH, Jiang L, Roys S, Puche AC, Gullapalli RP, Stone M, Prince JL, Zhuo J. Validation of Muscle Fiber Architecture of the Human Tongue Revealed by Diffusion Magnetic Resonance Imaging With Histology Verification. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2022; 65:3661-3673. [PMID: 36054846 PMCID: PMC9927595 DOI: 10.1044/2022_jslhr-22-00040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 04/14/2022] [Accepted: 06/14/2022] [Indexed: 06/15/2023]
Abstract
PURPOSE The goal of this study is to validate the muscle architecture derived from both ex vivo and in vivo diffusion-weighted magnetic resonance imaging (dMRI) of the human tongue with histology of an ex vivo tongue. METHOD dMRI was acquired with a 200-direction high angular resolution diffusion imaging (HARDI) diffusion scheme for both a postmortem head (imaged within 48 hr after death) and a healthy volunteer. After MRI, the postmortem head was fixed and the tongue excised for hematoxylin and eosin (H&E) staining and histology imaging. Structure tensor images were generated from the stained images to better demonstrate muscle fiber orientations. The tongue muscle fiber orientations, estimated from dMRI, were visualized using the tractogram, a novel representation of crossing fiber orientations, and compared against the histology images of the ex vivo tongue. RESULTS Muscle fibers identified in the tractograms showed good correspondence with those appearing in the histology images. We further demonstrated tongue muscle architecture in in vivo tractograms for the entire tongue. CONCLUSION The study demonstrates that dMRI can accurately reveal the complex muscle architecture of the human tongue and may potentially benefit planning and evaluation of oral surgery and research on speech and swallowing.
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Affiliation(s)
- Xiao Liang
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore
| | - Nahla M. H. Elsaid
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT
| | - Li Jiang
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore
| | - Steve Roys
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore
| | - Adam C. Puche
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore
| | - Rao P. Gullapalli
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore
| | - Maureen Stone
- Department of Neural and Pain Sciences and Department of Orthodontics, University of Maryland School of Dentistry, Baltimore
| | - Jerry L. Prince
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD
| | - Jiachen Zhuo
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore
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Leichter DM, Stark NE, Leary OP, Brodsky MB, Gilbert RJ, Nicosia MA. Two dimensional computational model coupling myoarchitecture-based lingual tissue mechanics with liquid bolus flow during oropharyngeal swallowing. Comput Biol Med 2022; 145:105446. [PMID: 35390748 DOI: 10.1016/j.compbiomed.2022.105446] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 03/13/2022] [Accepted: 03/21/2022] [Indexed: 11/25/2022]
Abstract
Biomechanical relationships involving lingual myoanatomy, contractility, and bolus movement are fundamental properties of human swallowing. To portray the relationship between lingual deformation and bolus flow during swallowing, a weakly one-way solid-fluid finite element model (FEM) was derived employing an elemental mesh aligned to magnetic resonance diffusional tractography (Q-space MRI, QSI) of the human tongue, an arbitrary Lagrangian-Eulerian (ALE) formulation with remeshing to account for the effects of lingual surface (boundary) deformation, an implementation of patterned fiber shortening, and a computational visualization of liquid bolus flow. Representing lingual tissue deformation in terms of its 2D principal Lagrangian strain in the mid-sagittal plane, we demonstrated that the swallow sequence was characterized by initial superior-anterior expansion directed towards the hard palate, followed by sequential, radially directed, contractions of the genioglossus and verticalis to promote lingual rotation (lateral perspective) and propulsive displacement. We specifically assessed local bolus velocity as a function of viscosity (perfect slip conditions) and observed that a low viscosity bolus (5 cP) exhibited maximal displacement, surface spreading and local velocity compared to medium (110 cP, 300 cP) and high (525 cP) viscosity boluses. Analysis of local nodal velocity revealed that all bolus viscosities exhibited a bi-phasic progression, with the low viscosity bolus being the most heterogeneous and fragmented and the high viscosity bolus being the most homogenous and cohesive. Intraoral bolus cohesion was depicted in terms of the distributed velocity gradient, with higher gradients being associated with increased shear rate and bolus fragmentation. Lastly, we made a sensitivity analysis on tongue stiffness and contractility by varying the degree of extracellular matrix (ECM) stiffness through effects on the Mooney-Rivlin derived passive matrix and by varying maximum tetanized isometric stress, and observed that a graded increase of ECM stiffness was associated with reduced bolus spreading, posterior displacement, and surface velocity gradients, whereas a reduction of global contractility resulted in a graded reduction of obtainable accommodation volume, absent bolus spreading, and loss of posterior displacement. We portray a unidirectionally coupled solid-liquid FEM which associates myoarchitecture-based lingual deformation with intra-oral bolus flow, and deduce that local elevation of the velocity gradient correlates with bolus fragmentation, a precondition believed to be associated with aspiration vulnerability during oropharyngeal swallowing.
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Affiliation(s)
- Dana M Leichter
- Center for Biomedical Engineering, Brown University, Providence, RI, 02912, USA; Research Service, Providence VA Medical Center, Providence, RI, 02908, USA
| | - Nicole E Stark
- Department of Mechanical Engineering, Widener University, Chester, PA, 19013, USA
| | - Owen P Leary
- Research Service, Providence VA Medical Center, Providence, RI, 02908, USA; Department of Pathology and Laboratory Medicine, Warren Alpert Medical School of Brown University, Providence, RI, 02903, USA
| | - Martin B Brodsky
- Department of Physical Medicine and Rehabilitation, Johns Hopkins University, USA
| | - Richard J Gilbert
- Research Service, Providence VA Medical Center, Providence, RI, 02908, USA; Department of Pathology and Laboratory Medicine, Warren Alpert Medical School of Brown University, Providence, RI, 02903, USA
| | - Mark A Nicosia
- Department of Mechanical Engineering, Widener University, Chester, PA, 19013, USA.
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Voskuilen L, Mazzoli V, Oudeman J, Balm AJM, van der Heijden F, Froeling M, de Win MML, Strijkers GJ, Smeele LE, Nederveen AJ. Crossing muscle fibers of the human tongue resolved in vivo using constrained spherical deconvolution. J Magn Reson Imaging 2019; 50:96-105. [PMID: 30648339 PMCID: PMC6617996 DOI: 10.1002/jmri.26609] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 11/26/2018] [Accepted: 11/27/2018] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Surgical resection of tongue cancer may impair swallowing and speech. Knowledge of tongue muscle architecture affected by the resection could aid in patient counseling. Diffusion tensor imaging (DTI) enables reconstructions of muscle architecture in vivo. Reconstructing crossing fibers in the tongue requires a higher-order diffusion model. PURPOSE To develop a clinically feasible diffusion imaging protocol, which facilitates both DTI and constrained spherical deconvolution (CSD) reconstructions of tongue muscle architecture in vivo. STUDY TYPE Cross-sectional study. SUBJECTS/SPECIMEN One ex vivo bovine tongue resected en bloc from mandible to hyoid bone. Ten healthy volunteers (mean age 25.5 years; range 21-34 years; four female). FIELD STRENGTH/SEQUENCE Diffusion-weighted echo planar imaging at 3 T using a high-angular resolution diffusion imaging scheme acquired twice with opposing phase-encoding for B0 -field inhomogeneity correction. The scan of the healthy volunteers was divided into four parts, in between which the volunteers were allowed to swallow, resulting in a total acquisition time of 10 minutes. ASSESSMENT The ability of resolving crossing muscle fibers using CSD was determined on the bovine tongue specimen. A reproducible response function was estimated and the optimal peak threshold was determined for the in vivo tongue. The quality of tractography of the in vivo tongue was graded by three experts. STATISTICAL TESTS The within-subject coefficient of variance was calculated for the response function. The qualitative results of the grading of DTI and CSD tractography were analyzed using a multilevel proportional odds model. RESULTS Fiber orientation distributions in the bovine tongue specimen showed that CSD was able to resolve crossing muscle fibers. The response function could be determined reproducibly in vivo. CSD tractography displayed significantly improved tractography compared with DTI tractography (P = 0.015). DATA CONCLUSION The 10-minute diffusion imaging protocol facilitates CSD fiber tracking with improved reconstructions of crossing tongue muscle fibers compared with DTI. LEVEL OF EVIDENCE 2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;50:96-105.
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Affiliation(s)
- Luuk Voskuilen
- Department of Head and Neck Oncology and Surgery, Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, Amsterdam, Netherlands.,Department of Radiology and Nuclear Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands.,Department of Oral and Maxillofacial Surgery, Academic Centre for Dentistry Amsterdam and Amsterdam UMC, University of Amsterdam and VU University Amsterdam, Amsterdam, Netherlands
| | | | - Jos Oudeman
- Department of Radiology and Nuclear Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Alfons J M Balm
- Department of Head and Neck Oncology and Surgery, Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, Amsterdam, Netherlands.,Department of Oral and Maxillofacial Surgery, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands.,Department of Robotics and Mechatronics, MIRA Institute, University of Twente, Enschede, Netherlands
| | - Ferdinand van der Heijden
- Department of Head and Neck Oncology and Surgery, Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, Amsterdam, Netherlands.,Department of Robotics and Mechatronics, MIRA Institute, University of Twente, Enschede, Netherlands
| | - Martijn Froeling
- Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Maartje M L de Win
- Department of Radiology and Nuclear Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Gustav J Strijkers
- Department of Biomedical Engineering and Physics, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Ludi E Smeele
- Department of Head and Neck Oncology and Surgery, Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, Amsterdam, Netherlands.,Department of Oral and Maxillofacial Surgery, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Aart J Nederveen
- Department of Radiology and Nuclear Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
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Taylor EN, Ding Y, Zhu S, Cheah E, Alexander P, Lin L, Aninwene GE, Hoffman MP, Mahajan A, Mohamed AS, McDannold N, Fuller CD, Chen CC, Gilbert RJ. Association between tumor architecture derived from generalized Q-space MRI and survival in glioblastoma. Oncotarget 2017; 8:41815-41826. [PMID: 28404971 PMCID: PMC5522030 DOI: 10.18632/oncotarget.16296] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 01/24/2017] [Indexed: 01/22/2023] Open
Abstract
While it is recognized that the overall resistance of glioblastoma to treatment may be related to intra-tumor patterns of structural heterogeneity, imaging methods to assess such patterns remain rudimentary. METHODS We utilized a generalized Q-space imaging (GQI) algorithm to analyze magnetic resonance imaging (MRI) derived from a rodent model of glioblastoma and 2 clinical datasets to correlate GQI, histology, and survival. RESULTS In a rodent glioblastoma model, GQI demonstrated a poorly coherent core region, consisting of diffusion tracts <5 mm, surrounded by a shell of highly coherent diffusion tracts, 6-25 mm. Histologically, the core region possessed a high degree of necrosis, whereas the shell consisted of organized sheets of anaplastic cells with elevated mitotic index. These attributes define tumor architecture as the macroscopic organization of variably aligned tumor cells. Applied to MRI data from The Cancer Imaging Atlas (TCGA), the core-shell diffusion tract-length ratio (c/s ratio) correlated linearly with necrosis, which, in turn, was inversely associated with survival (p = 0.00002). We confirmed in an independent cohort of patients (n = 62) that the c/s ratio correlated inversely with survival (p = 0.0004). CONCLUSIONS The analysis of MR images by GQI affords insight into tumor architectural patterns in glioblastoma that correlate with biological heterogeneity and clinical outcome.
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Affiliation(s)
- Erik N. Taylor
- Chemistry and Chemical Biology, Northeastern University, Boston, MA, USA
| | - Yao Ding
- Radiation Oncology, University of Texas, MD Anderson Cancer Center, Houston, TX, USA
| | - Shan Zhu
- Chemistry and Chemical Biology, Northeastern University, Boston, MA, USA
| | - Eric Cheah
- Chemistry and Chemical Biology, Northeastern University, Boston, MA, USA
| | - Phillip Alexander
- Department of Radiology, Brigham and Women’s Hospital, Boston, MA, USA
- Department of Engineering Science, University of Oxford, Oxford, UK
| | - Leon Lin
- Chemistry and Chemical Biology, Northeastern University, Boston, MA, USA
| | - George E. Aninwene
- Chemistry and Chemical Biology, Northeastern University, Boston, MA, USA
| | - Matthew P. Hoffman
- Chemistry and Chemical Biology, Northeastern University, Boston, MA, USA
| | - Anita Mahajan
- Radiation Oncology, University of Texas, MD Anderson Cancer Center, Houston, TX, USA
| | - Abdallah S.R. Mohamed
- Radiation Oncology, University of Texas, MD Anderson Cancer Center, Houston, TX, USA
| | - Nathan McDannold
- Department of Radiology, Brigham and Women’s Hospital, Boston, MA, USA
| | - Clifton D. Fuller
- Radiation Oncology, University of Texas, MD Anderson Cancer Center, Houston, TX, USA
| | - Clark C. Chen
- Center for Theoretical and Applied Neuro-Oncology and Department of Neurosurgery, University of California, San Diego, CA, USA
| | - Richard J. Gilbert
- Chemistry and Chemical Biology, Northeastern University, Boston, MA, USA
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Hoffman MP, Taylor EN, Aninwene GE, Sadayappan S, Gilbert RJ. Assessing the multiscale architecture of muscular tissue with Q-space magnetic resonance imaging: Review. Microsc Res Tech 2016; 81:162-170. [PMID: 27696640 DOI: 10.1002/jemt.22777] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2015] [Revised: 08/22/2016] [Accepted: 08/24/2016] [Indexed: 01/14/2023]
Abstract
Contraction of muscular tissue requires the synchronized shortening of myofibers arrayed in complex geometrical patterns. Imaging such myofiber patterns with diffusion-weighted MRI reveals architectural ensembles that underlie force generation at the organ scale. Restricted proton diffusion is a stochastic process resulting from random translational motion that may be used to probe the directionality of myofibers in whole tissue. During diffusion-weighted MRI, magnetic field gradients are applied to determine the directional dependence of proton diffusion through the analysis of a diffusional probability distribution function (PDF). The directions of principal (maximal) diffusion within the PDF are associated with similarly aligned diffusion maxima in adjacent voxels to derive multivoxel tracts. Diffusion-weighted MRI with tractography thus constitutes a multiscale method for depicting patterns of cellular organization within biological tissues. We provide in this review, details of the method by which generalized Q-space imaging is used to interrogate multidimensional diffusion space, and thereby to infer the organization of muscular tissue. Q-space imaging derives the lowest possible angular separation of diffusion maxima by optimizing the conditions by which magnetic field gradients are applied to a given tissue. To illustrate, we present the methods and applications associated with Q-space imaging of the multiscale myoarchitecture associated with the human and rodent tongues. These representations emphasize the intricate and continuous nature of muscle fiber organization and suggest a method to depict structural "blueprints" for skeletal and cardiac muscle tissue.
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Affiliation(s)
- Matthew P Hoffman
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115, USA
| | - Erik N Taylor
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115, USA
| | - George E Aninwene
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115, USA
| | - Sakthivel Sadayappan
- Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University of Chicago, Maywood, IL, 60153, USA
| | - Richard J Gilbert
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115, USA
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Taylor EN, Hoffman MP, Barefield DY, Aninwene GE, Abrishamchi AD, Lynch TL, Govindan S, Osinska H, Robbins J, Sadayappan S, Gilbert RJ. Alterations in Multi-Scale Cardiac Architecture in Association With Phosphorylation of Myosin Binding Protein-C. J Am Heart Assoc 2016; 5:e002836. [PMID: 27068630 PMCID: PMC4943261 DOI: 10.1161/jaha.115.002836] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Background The geometric organization of myocytes in the ventricular wall comprises the structural underpinnings of cardiac mechanical function. Cardiac myosin binding protein‐C (MYBPC3) is a sarcomeric protein, for which phosphorylation modulates myofilament binding, sarcomere morphology, and myocyte alignment in the ventricular wall. To elucidate the mechanisms by which MYBPC3 phospho‐regulation affects cardiac tissue organization, we studied ventricular myoarchitecture using generalized Q‐space imaging (GQI). GQI assessed geometric phenotype in excised hearts that had undergone transgenic (TG) modification of phospho‐regulatory serine sites to nonphosphorylatable alanines (MYBPC3AllP−/(t/t)) or phospho‐mimetic aspartic acids (MYBPC3AllP+/(t/t)). Methods and Results Myoarchitecture in the wild‐type (MYBPC3WT) left‐ventricle (LV) varied with transmural position, with helix angles ranging from −90/+90 degrees and contiguous circular orientation from the LV mid‐myocardium to the right ventricle (RV). Whereas MYBPC3AllP+/(t/t) hearts were not architecturally distinct from MYBPC3WT, MYBPC3AllP−/(t/t) hearts demonstrated a significant reduction in LV transmural helicity. Null MYBPC3(t/t) hearts, as constituted by a truncated MYBPC3 protein, demonstrated global architectural disarray and loss in helicity. Electron microscopy was performed to correlate the observed macroscopic architectural changes with sarcomere ultrastructure and demonstrated that impaired phosphorylation of MYBPC3 resulted in modifications of the sarcomere aspect ratio and shear angle. The mechanical effect of helicity loss was assessed through a geometric model relating cardiac work to ejection fraction, confirming the mechanical impairments observed with echocardiography. Conclusions We conclude that phosphorylation of MYBPC3 contributes to the genesis of ventricular wall geometry, linking myofilament biology with multiscale cardiac mechanics and myoarchitecture.
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Affiliation(s)
- Erik N Taylor
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA
| | - Matthew P Hoffman
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA
| | - David Y Barefield
- Health Sciences Division, Department of Cell and Molecular Physiology, Loyola University of Chicago, Maywood, IL
| | - George E Aninwene
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA
| | - Aurash D Abrishamchi
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA
| | - Thomas L Lynch
- Health Sciences Division, Department of Cell and Molecular Physiology, Loyola University of Chicago, Maywood, IL
| | - Suresh Govindan
- Health Sciences Division, Department of Cell and Molecular Physiology, Loyola University of Chicago, Maywood, IL
| | - Hanna Osinska
- Division of Molecular Cardiovascular Biology, Department of Pediatrics, The Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH
| | - Jeffrey Robbins
- Division of Molecular Cardiovascular Biology, Department of Pediatrics, The Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH
| | - Sakthivel Sadayappan
- Health Sciences Division, Department of Cell and Molecular Physiology, Loyola University of Chicago, Maywood, IL
| | - Richard J Gilbert
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA
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Patterns of intersecting fiber arrays revealed in whole muscle with generalized Q-space imaging. Biophys J 2016; 108:2740-9. [PMID: 26039175 DOI: 10.1016/j.bpj.2015.03.061] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 03/01/2015] [Accepted: 03/31/2015] [Indexed: 01/15/2023] Open
Abstract
The multiscale attributes of mammalian muscle confer significant challenges for structural imaging in vivo. To achieve this, we employed a magnetic resonance method, termed "generalized Q-space imaging", that considers the effect of spatially distributed diffusion-weighted magnetic field gradients and diffusion sensitivities on the morphology of Q-space. This approach results in a subvoxel scaled probability distribution function whose shape correlates with local fiber orientation. The principal fiber populations identified within these probability distribution functions can then be associated by streamline methods to create multivoxel tractlike constructs that depict the macroscale orientation of myofiber arrays. We performed a simulation of Q-space input parameters, including magnetic field gradient strength and direction, diffusion sensitivity, and diffusional sampling to determine the optimal achievable fiber angle separation in the minimum scan time. We applied this approach to resolve intravoxel crossing myofiber arrays in the setting of the human tongue, an organ with anatomic complexity based on the presence of hierarchical arrays of intersecting myocytes. Using parameters defined by simulation, we imaged at 3T the fanlike configuration of the human genioglossus and the laterally positioned merging fibers of the styloglossus, inferior longitudinalis, chondroglossus, and verticalis. Comparative scans of the excised mouse tongue at 7T demonstrated similar midline and lateral crossing fiber patterns, whereas histological analysis confirmed the presence and distribution of these myofiber arrays at the microscopic scale. Our results demonstrate a magnetic resonance method for acquiring and displaying diffusional data that defines highly ordered myofiber patterns in architecturally complex tissue. Such patterns suggest inherent multiscale fiber organization and provide a basis for structure-function analyses in vivo and in model tissues.
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Chu CY, Huang JP, Sun CY, Liu WY, Zhu YM. Resolving intravoxel fiber architecture using nonconvex regularized blind compressed sensing. Phys Med Biol 2015; 60:2339-54. [PMID: 25716031 DOI: 10.1088/0031-9155/60/6/2339] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
In diffusion magnetic resonance imaging, accurate and reliable estimation of intravoxel fiber architectures is a major prerequisite for tractography algorithms or any other derived statistical analysis. Several methods have been proposed that estimate intravoxel fiber architectures using low angular resolution acquisitions owing to their shorter acquisition time and relatively low b-values. But these methods are highly sensitive to noise. In this work, we propose a nonconvex regularized blind compressed sensing approach to estimate intravoxel fiber architectures in low angular resolution acquisitions. The method models diffusion-weighted (DW) signals as a sparse linear combination of unfixed reconstruction basis functions and introduces a nonconvex regularizer to enhance the noise immunity. We present a general solving framework to simultaneously estimate the sparse coefficients and the reconstruction basis. Experiments on synthetic, phantom, and real human brain DW images demonstrate the superiority of the proposed approach.
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Affiliation(s)
- C Y Chu
- HIT-INSA Sino French Research Centre fssor Biomedical Imaging, Harbin Institute of Technology, Harbin, People's Republic of China. CREATIS, CNRS UMR 5220, Inserm U630, INSA of Lyon, University of Lyon, Villeurbanne, France
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Mittal RK, Bhargava V, Sheean G, Ledgerwood M, Sinha S. Purse-string morphology of external anal sphincter revealed by novel imaging techniques. Am J Physiol Gastrointest Liver Physiol 2014; 306:G505-14. [PMID: 24458022 PMCID: PMC3949029 DOI: 10.1152/ajpgi.00338.2013] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The external anal sphincter (EAS) may be injured in 25-35% of women during the first and subsequent vaginal childbirths and is likely the most common cause of anal incontinence. Since its first description almost 300 years ago, the EAS was believed to be a circular or a "donut-shaped" structure. Using three-dimensional transperineal ultrasound imaging, MRI, diffusion tensor imaging, and muscle fiber tracking, we delineated various components of the EAS and their muscle fiber directions. These novel imaging techniques suggest "purse-string" morphology, with "EAS muscles" crossing contralaterally in the perineal body to the contralateral transverse perineal (TP) and bulbospongiosus (BS) muscles, thus attaching the EAS to the pubic rami. Spin-tag MRI demonstrated purse-string action of the EAS muscle. Electromyography of TP/BS and EAS muscles revealed their simultaneous contraction and relaxation. Lidocaine injection into the TP/BS muscle significantly reduced anal canal pressure. These studies support purse-string morphology of the EAS to constrict/close the anal canal opening. Our findings have implications for the effect of episiotomy on anal closure function and the currently used surgical technique (overlapping sphincteroplasty) for EAS reconstructive surgery to treat anal incontinence.
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Affiliation(s)
- Ravinder K. Mittal
- 1Division of Gastroenterology, Department of Medicine, University of California San Diego, San Diego, California; ,4San Diego Veterans Affairs Healthcare System, San Diego, California
| | - Valmik Bhargava
- 1Division of Gastroenterology, Department of Medicine, University of California San Diego, San Diego, California; ,4San Diego Veterans Affairs Healthcare System, San Diego, California
| | - Geoff Sheean
- 2Department of Neurology, University of California San Diego, San Diego, California;
| | - Melissa Ledgerwood
- 1Division of Gastroenterology, Department of Medicine, University of California San Diego, San Diego, California;
| | - Shantanu Sinha
- 3Department of Radiology, University of California San Diego, San Diego, California; and
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Fiocchi F, Nocetti L, Siopis E, Currà S, Costi T, Ligabue G, Torricelli P. In vivo 3 T MR diffusion tensor imaging for detection of the fibre architecture of the human uterus: a feasibility and quantitative study. Br J Radiol 2012; 85:e1009-17. [PMID: 22744322 DOI: 10.1259/bjr/76693739] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVE The aim of this study was to investigate the feasibility of depicting fibre architecture of human uteri in vivo using 3 T MR diffusion tensor imaging (MR-DTI) with a three-dimensional (3D) tractography approach. Quantitative results were provided. METHODS In vivo 3 T MR-DTI was performed on 30 volunteers (9 Caesarean delivery). Main diffusion directions reflecting the fibre orientation were determined using sensitivity-encoding single-shot echo planar imaging with diffusion-sensitised gradients (b=600 mm(2) s(-1)) along 32 directions. A deterministic fibre-tracking algorithm was used to show in vivo fibre architecture, compared with ex vivo histological slides of cadaveric uteri. The number of fibres, the fibre density, the fractional anisotropy (FA) and the apparent diffusion coefficient (ADC) were measured in 13 volunteers. RESULTS Anisotropy was found in most regions of normal uteri and the preferential order of uterine fibres depicted, consisting of two representative fibre directions: circular and longitudinal, as in ex vivo studies. Two-thirds of uteri with a Caesarean scar did not have the same orientation of fibres in the anterior isthmus when compared with non-scarred myometrium. Quantitative data were obtained from 13 volunteers: Caesarean-scarred uteri (n=5) showed lower fibre number and density in the scarred anterior isthmus than the nulliparous uteri (n=8). No significant differences were found in FA (0.42 ± 0.02, 0.41 ± 0.02; p=0.25) and ADC (1.82 ± 0.18 × 10(-3) mm(2) s(-1), 1.93 ± 0.25 × 10(-3) mm(2) s(-1); p=0.20). CONCLUSION Fibre architecture of the human uterus can be depicted in vivo using 3 T MR-DTI. Advances in knowledge 3 T MR-DTI can help to provide an in vivo insight of uterine anatomy non-invasively, especially in females with previous Caesarean surgery, in order to provide better management of subsequent deliveries.
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Affiliation(s)
- F Fiocchi
- Department of Diagnostic Radiology, Policlinico Hospital, University of Modena and Reggio-Emilia, Modena, Italy.
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Mijailovich SM, Stojanovic B, Kojic M, Liang A, Wedeen VJ, Gilbert RJ. Derivation of a finite-element model of lingual deformation during swallowing from the mechanics of mesoscale myofiber tracts obtained by MRI. J Appl Physiol (1985) 2010; 109:1500-14. [PMID: 20689096 PMCID: PMC2980378 DOI: 10.1152/japplphysiol.00493.2010] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Accepted: 07/30/2010] [Indexed: 11/22/2022] Open
Abstract
To demonstrate the relationship between lingual myoarchitecture and mechanics during swallowing, we performed a finite-element (FE) simulation of lingual deformation employing mesh aligned with the vector coordinates of myofiber tracts obtained by diffusion tensor imaging with tractography in humans. Material properties of individual elements were depicted in terms of Hill's three-component phenomenological model, assuming that the FE mesh was composed of anisotropic muscle and isotropic connective tissue. Moreover, the mechanical model accounted for elastic constraints by passive and active elements from the superior and inferior directions and the effect of out-of-plane muscles and connective tissue. Passive bolus effects were negligible. Myofiber tract activation was simulated over 500 ms in 1-ms steps following lingual tip association with the hard palate and incorporated specifically the accommodative and propulsive phases of the swallow. Examining the displacement field, active and passive muscle stress, elemental stretch, and strain rate relative to changes of global shape, we demonstrate that lingual reconfiguration during these swallow phases is characterized by (in sequence) the following: 1) lingual tip elevation and shortening in the anterior-posterior direction; 2) inferior displacement related to hyoglossus contraction at its inferior-most position; and 3) dominant clockwise rotation related to regional contraction of the genioglossus and contraction of the hyoglossus following anterior displacement. These simulations demonstrate that lingual deformation during the indicated phases of swallowing requires temporally patterned activation of intrinsic and extrinsic muscles and delineate a method to ascertain the mechanics of normal and pathological swallowing.
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Affiliation(s)
- Srboljub M Mijailovich
- Molecular and Integrative Physiological Sciences, Department of Environmental Health, Harvard School of Public Health, Boston, MA 02115, USA.
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Wang TT, Kwon HS, Dai G, Wang R, Mijailovich SM, Moss RL, So PTC, Wedeen VJ, Gilbert RJ. Resolving myoarchitectural disarray in the mouse ventricular wall with diffusion spectrum magnetic resonance imaging. Ann Biomed Eng 2010; 38:2841-50. [PMID: 20461466 DOI: 10.1007/s10439-010-0031-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Accepted: 03/30/2010] [Indexed: 10/19/2022]
Abstract
The myoarchitecture of the ventricular wall provides a structural template dictating tissue-scale patterns of mechanical function. We studied whether myofiber tract imaging performed with MR diffusion spectrum imaging (DSI) tractography has the capacity to resolve abnormalities of ventricular myoarchitecture in a model of congenital hypertrophic cardiomyopathy (HCM) associated with the ablation of myosin binding protein-C (MyBP-C). Homozygous MyBP-C knockout mice were generated by deletion of exons 3-10 from the endogenous MyBP-C gene. Fiber alignment in the left ventricular wall of wild type mice was depicted through DSI tractography (and confirmed by multi-slice two-photon microscopy) as a set of helical structures whose angles display a continuous transition from negative in the subepicardium to positive in the subendocardium. In contrast, the hearts obtained from the MyBP-C knockouts displayed substantial myoarchitectural disarray, characterized by a loss of voxel-to-voxel orientational coherence for fibers principally located in the mid-myocardium-subendocardium and impairment of the transmural progression of helix angles. These results substantiate the use of DSI tractography in determining myoarchitectural disarray in models of cardiomyopathy and suggest a biological association between myofilament expression, cardiac fiber alignment, and torsional rotation in the setting of congenital HCM.
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Affiliation(s)
- Teresa T Wang
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, USA
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Sosnovik DE, Wang R, Dai G, Reese TG, Wedeen VJ. Diffusion MR tractography of the heart. J Cardiovasc Magn Reson 2009; 11:47. [PMID: 19912654 PMCID: PMC2781805 DOI: 10.1186/1532-429x-11-47] [Citation(s) in RCA: 127] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2009] [Accepted: 11/13/2009] [Indexed: 12/17/2022] Open
Abstract
Histological studies have shown that the myocardium consists of an array of crossing helical fiber tracts. Changes in myocardial fiber architecture occur in ischemic heart disease and heart failure, and can be imaged non-destructively with diffusion-encoded MR. Several diffusion-encoding schemes have been developed, ranging from scalar measurements of mean diffusivity to a 6-dimensional imaging technique known as diffusion spectrum imaging or DSI. The properties of DSI make it particularly suited to the generation of 3-dimensional tractograms of myofiber architecture. In this article we review the physical basis of diffusion-tractography in the myocardium and the attributes of the available techniques, placing particular emphasis on DSI. The application of DSI in ischemic heart disease is reviewed, and the requisites for widespread clinical translation of diffusion MR tractography in the heart are discussed.
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Affiliation(s)
- David E Sosnovik
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston MA, USA
- Cardiology Division, Massachusetts General Hospital, Harvard Medical School, Boston MA, USA
- Center for Molecular Imaging Research, Massachusetts General Hospital, Harvard Medical School, Boston MA, USA
- Harvard-MIT Division of Health Sciences and Technology, Cambridge MA, USA
| | - Ruopeng Wang
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston MA, USA
| | - Guangping Dai
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston MA, USA
| | - Timothy G Reese
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston MA, USA
| | - Van J Wedeen
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston MA, USA
- Harvard-MIT Division of Health Sciences and Technology, Cambridge MA, USA
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