1
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Co M, Raterman B, Klamer B, Kolipaka A, Walter B. Nucleus pulposus structure and function assessed in shear using magnetic resonance elastography, quantitative MRI, and rheometry. JOR Spine 2024; 7:e1335. [PMID: 38741919 PMCID: PMC11089841 DOI: 10.1002/jsp2.1335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 04/04/2024] [Accepted: 04/15/2024] [Indexed: 05/16/2024] Open
Abstract
Background In vivo quantification of the structure-function relationship of the intervertebral disc (IVD) via quantitative MRI has the potential to aid objective stratification of disease and evaluation of restorative therapies. Magnetic resonance elastography (MRE) is an imaging technique that assesses tissue shear properties and combined with quantitative MRI metrics reflective of composition can inform structure-function of the IVD. The objectives of this study were to (1) compare MRE- and rheometry-derived shear modulus in agarose gels and nucleus pulposus (NP) tissue and (2) correlate MRE and rheological measures of NP tissue with composition and quantitative MRI. Method MRE and MRI assessment (i.e., T1ρ and T2 mapping) of agarose samples (2%, 3%, and 4% (w/v); n = 3-4/%) and of bovine caudal IVDs after equilibrium dialysis in 5% or 25% PEG (n = 13/PEG%) was conducted. Subsequently, agarose and NP tissue underwent torsional mechanical testing consisting of a frequency sweep from 1 to 100 Hz at a rotational strain of 0.05%. NP tissue was additionally evaluated under creep and stress relaxation conditions. Linear mixed-effects models and univariate regression analyses evaluated the effects of testing method, %agarose or %PEG, and frequency, as well as correlations between parameters. Results MRE- and rheometry-derived shear moduli were greater at 100 Hz than at 80 Hz in all agarose and NP tissue samples. Additionally, all samples with lower water content had higher complex shear moduli. There was a significant correlation between MRE- and rheometry-derived modulus values for homogenous agarose samples. T1ρ and T2 relaxation times for agarose and tissue were negatively correlated with complex shear modulus derived from both techniques. For NP tissue, shear modulus was positively correlated with GAG/wet-weight and negatively correlated with %water content. Conclusion This work demonstrates that MRE can assess hydration-induced changes in IVD shear properties and further highlights the structure-function relationship between composition and shear mechanical behaviors of NP tissue.
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Affiliation(s)
- Megan Co
- Department of Biomedical EngineeringThe Ohio State UniversityColumbusOhioUSA
| | - Brian Raterman
- Department of RadiologyThe Ohio State University Wexner Medical CenterColumbusOhioUSA
| | - Brett Klamer
- Department of Biomedical Informatics, Center for BiostatisticsThe Ohio State UniversityColumbusOhioUSA
| | - Arunark Kolipaka
- Department of RadiologyThe Ohio State University Wexner Medical CenterColumbusOhioUSA
| | - Benjamin Walter
- Department of Biomedical EngineeringThe Ohio State UniversityColumbusOhioUSA
- Department of OrthopaedicsThe Ohio State University Wexner Medical CenterColumbusOhioUSA
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2
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Davis ZR, Gossett PC, Wilson RL, Kim W, Mei Y, Butz KD, Emery NC, Nauman EA, Avril S, Neu CP, Chan DD. Intervertebral Disc Elastography to Relate Shear Modulus and Relaxometry in Compression and Bending. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.01.555817. [PMID: 37732250 PMCID: PMC10508717 DOI: 10.1101/2023.09.01.555817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
Intervertebral disc degeneration is the most recognized cause of low back pain, characterized by the decline of tissue structure and mechanics. Image-based mechanical parameters (e.g., strain, stiffness) may provide an ideal assessment of disc function that is lost with degeneration but unfortunately remains underdeveloped. Moreover, it is unknown whether strain or stiffness of the disc may be predicted by MRI relaxometry (e.g. T1 or T2), an increasingly accepted quantitative measure of disc structure. In this study, we quantified T1 and T2 relaxation times and in-plane strains using displacement-encoded MRI within the disc under physiological levels of compression and bending. We then estimated shear modulus in orthogonal image planes and compared these values to relaxation times and strains within regions of the disc. Intratissue strain depended on the loading mode, and shear modulus in the nucleus pulposus was typically an order of magnitude lower than the annulus fibrosis, except in bending, where the apparent stiffness depended on the loading. Relative shear moduli estimated from strain data derived under compression generally did not correspond with those from bending experiments, with no correlations in the sagittal plane and only 4 of 15 regions correlated in the coronal plane, suggesting that future inverse models should incorporate multiple loading conditions. Strain imaging and strain-based estimation of material properties may serve as imaging biomarkers to distinguish healthy and diseased discs. Additionally, image-based elastography and relaxometry may be viewed as complementary measures of disc structure and function to assess degeneration in longitudinal studies.
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Affiliation(s)
- Zachary R. Davis
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Paull C. Gossett
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Robert L. Wilson
- Paul M. Rady Department of Mechanical Engineering, University of Colorado, Boulder, CO, USA
| | - Woong Kim
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Yue Mei
- State Key Laboratory of Structural Analysis for Industrial Equipment and International Research Center for Computational Mechanics, Department of Engineering Mechanics, Dalian University of Technology, Dalian, China
- Mines Saint-Étienne, Université Jean Monnet, INSERM, U 1059 Sainbiose, 42023, SaintÉtienne, France
| | - Kent D. Butz
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
- School of Mechanical Engineering, Purdue University, West Lafayette, IN, USA
| | - Nancy C. Emery
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
| | - Eric A. Nauman
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
- School of Mechanical Engineering, Purdue University, West Lafayette, IN, USA
- Department of Biomedical Engineering, University of Cincinnati, Cincinnati, OH, USA
| | - Stéphane Avril
- Mines Saint-Étienne, Université Jean Monnet, INSERM, U 1059 Sainbiose, 42023, SaintÉtienne, France
| | - Corey P. Neu
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
- Paul M. Rady Department of Mechanical Engineering, University of Colorado, Boulder, CO, USA
- Biomedical Engineering Program, University of Colorado, Boulder, CO, USA
- BioFrontiers Institute, University of Colorado, Boulder, CO, USA
| | - Deva D. Chan
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
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3
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Meadows KD, Peloquin JM, Newman HR, Cauchy PJK, Vresilovic EJ, Elliott DM. MRI
‐based measurement of in vivo disc mechanics in a young population due to flexion, extension, and diurnal loading. JOR Spine 2023; 6:e1243. [PMID: 36994458 PMCID: PMC10041375 DOI: 10.1002/jsp2.1243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 12/14/2022] [Accepted: 12/21/2022] [Indexed: 01/12/2023] Open
Abstract
Background Intervertebral disc degeneration is often implicated in low back pain; however, discs with structural degeneration often do not cause pain. It may be that disc mechanics can provide better diagnosis and identification of the pain source. In cadaveric testing, the degenerated disc has altered mechanics, but in vivo, disc mechanics remain unknown. To measure in vivo disc mechanics, noninvasive methods must be developed to apply and measure physiological deformations. Aim Thus, this study aimed to develop methods to measure disc mechanical function via noninvasive MRI during flexion and extension and after diurnal loading in a young population. This data will serve as baseline disc mechanics to later compare across ages and in patients. Materials & Methods To accomplish this, subjects were imaged in the morning in a reference supine position, in flexion, in extension, and at the end of the day in a supine position. Disc deformations and vertebral motions were used to quantify disc axial strain, changes in wedge angle, and anterior-posterior (A-P) shear displacement. T2 weighted MRI was also used to evaluate disc degeneration via Pfirrmann grading and T2 time. All measures were then tested for effect of sex and disc level. Results We found that flexion and extension caused level-dependent strains in the anterior and posterior of the disc, changes in wedge angle, and A-P shear displacements. Flexion had higher magnitude changes overall. Diurnal loading did not cause level-dependent strains but did cause small level-dependent changes in wedge angle and A-P shear displacements. Discussion Correlations between disc degeneration and mechanics were largest in flexion, likely due to the smaller contribution of the facet joints in this condition. Conclusion In summary, this study established methods to measure in vivo disc mechanical function via noninvasive MRI and established a baseline in a young population that may be compared to older subjects and clinical disorders in the future.
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Affiliation(s)
- Kyle D. Meadows
- Department of Biomedical Engineering University of Delaware Newark Delaware USA
| | - John M. Peloquin
- Department of Biomedical Engineering University of Delaware Newark Delaware USA
| | - Harrah R. Newman
- Department of Biomedical Engineering University of Delaware Newark Delaware USA
| | - Peter J. K. Cauchy
- Department of Biomedical Engineering University of Delaware Newark Delaware USA
| | | | - Dawn M. Elliott
- Department of Biomedical Engineering University of Delaware Newark Delaware USA
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4
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Co M, Dong H, Boulter DJ, Nguyen XV, Khan SN, Raterman B, Klamer B, Kolipaka A, Walter BA. Magnetic Resonance Elastography of Intervertebral Discs: Spin-Echo Echo-Planar Imaging Sequence Validation. J Magn Reson Imaging 2022; 56:1722-1732. [PMID: 35289470 PMCID: PMC9475395 DOI: 10.1002/jmri.28151] [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: 07/08/2021] [Revised: 02/23/2022] [Accepted: 02/25/2022] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Magnetic resonance elastography (MRE) is an imaging technique that can noninvasively assess the shear properties of the intervertebral disc (IVD). Unlike the standard gradient recalled echo (GRE) MRE technique, a spin-echo echo-planar imaging (SE-EPI) sequence has the potential to improve imaging efficiency and patient compliance. PURPOSE To validate the use of an SE-EPI sequence for MRE of the IVD compared against the standard GRE sequence. STUDY TYPE Cross-over. SUBJECTS Twenty-eight healthy volunteers (15 males and 13 females, age range: 19-55). FIELD STRENGTH/SEQUENCE 3 T; GRE, SE-EPI with breath holds (SE-EPI-BH) and SE-EPI with free breathing (SE-EPI-FB) MRE sequences. ASSESSMENT MRE-derived shear stiffnesses were calculated via principal frequency analysis. SE-EPI derived shear stiffness and octahedral shear strain signal-to-noise ratios (OSS-SNR) were compared against those derived using the GRE sequence. The reproducibility and repeatability of SE-EPI stiffness measurements were determined. Shear stiffness was evaluated in the nucleus pulposus (NP) and annulus fibrosus (AF) regions of the disc. Scan times between sequences were compared. STATISTICAL TESTS Linear mixed models, Bland-Altman plots, and Lin's concordance correlation coefficients (CCCs) were used with P < 0.05 considered statistically significant. RESULTS Good correlation was observed between shear stiffnesses derived from the SE-EPI sequences with those derived from the GRE sequence with CCC values greater than 0.73 and 0.78 for the NP and AF regions, respectively. OSS-SNR was not significantly different between GRE and SE-EPI sequences (P > 0.05). SE-EPI sequences generated highly reproducible and repeatable stiffness measurements with CCC values greater than 0.97 in the NP and AF regions and reduced scan time by at least 51% compared to GRE. SE-EPI-BH and SE-EPI-FB stiffness measurements were similar with CCC values greater than 0.98 for both regions. DATA CONCLUSION SE-EPI-based MRE-derived stiffnesses were highly reproducible and repeatable and correlated with current standard GRE MRE-derived stiffness estimates while reducing scan times. LEVEL OF EVIDENCE 1 TECHNICAL EFFICACY STAGE: 1.
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Affiliation(s)
- Megan Co
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Huiming Dong
- Department of Radiology, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Daniel J Boulter
- Department of Radiology, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Xuan V Nguyen
- Department of Radiology, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Safdar N Khan
- Department of Orthopedics, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Brian Raterman
- Department of Radiology, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Brett Klamer
- Center for Biostatistics, The Ohio State University, Columbus, Ohio, USA
| | - Arunark Kolipaka
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio, USA
- Department of Radiology, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Benjamin A Walter
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio, USA
- Department of Radiology, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
- Spine Research Institute, The Ohio State University, Columbus, Ohio, USA
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5
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Tavakoli J, Geargeflia S, Tipper JL, Diwan AD. Magnetic resonance elastography: A non-invasive biomarker for low back pain studies. BIOMEDICAL ENGINEERING ADVANCES 2021. [DOI: 10.1016/j.bea.2021.100014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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6
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In vivo intervertebral disc deformation: intratissue strain patterns within adjacent discs during flexion-extension. Sci Rep 2021; 11:729. [PMID: 33436667 PMCID: PMC7804136 DOI: 10.1038/s41598-020-77577-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 11/10/2020] [Indexed: 01/29/2023] Open
Abstract
The biomechanical function of the intervertebral disc (IVD) is a critical indicator of tissue health and pathology. The mechanical responses (displacements, strain) of the IVD to physiologic movement can be spatially complex and depend on tissue architecture, consisting of distinct compositional regions and integrity; however, IVD biomechanics are predominately uncharacterized in vivo. Here, we measured voxel-level displacement and strain patterns in adjacent IVDs in vivo by coupling magnetic resonance imaging (MRI) with cyclic motion of the cervical spine. Across adjacent disc segments, cervical flexion-extension of 10° resulted in first principal and maximum shear strains approaching 10%. Intratissue spatial analysis of the cervical IVDs, not possible with conventional techniques, revealed elevated maximum shear strains located in the posterior disc (nucleus pulposus) regions. IVD structure, based on relaxometric patterns of T2 and T1ρ images, did not correlate spatially with functional metrics of strain. Our approach enables a comprehensive IVD biomechanical analysis of voxel-level, intratissue strain patterns in adjacent discs in vivo, which are largely independent of MRI relaxometry. The spatial mapping of IVD biomechanics in vivo provides a functional assessment of adjacent IVDs in subjects, and provides foundational biomarkers for elastography, differentiation of disease state, and evaluation of treatment efficacy.
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7
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Ashinsky BG, Gullbrand SE, Wang C, Bonnevie ED, Han L, Mauck RL, Smith HE. Degeneration alters structure-function relationships at multiple length-scales and across interfaces in human intervertebral discs. J Anat 2020; 238:986-998. [PMID: 33205444 DOI: 10.1111/joa.13349] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 09/19/2020] [Accepted: 10/08/2020] [Indexed: 12/19/2022] Open
Abstract
Intervertebral disc (IVD) degeneration and associated back pain place a significant burden on the population. IVD degeneration is a progressive cascade of cellular, compositional, and structural changes, which results in a loss of disc height, disorganization of extracellular matrix architecture, tears in the annulus fibrosus which may involve herniation of the nucleus pulposus, and remodeling of the bony and cartilaginous endplates (CEP). These changes to the IVD often occur concomitantly, across the entire motion segment from the disc subcomponents to the CEP and vertebral bone, making it difficult to determine the causal initiating factor of degeneration. Furthermore, assessments of the subcomponents of the IVD have been largely qualitative, with most studies focusing on a single attribute, rather than multiple adjacent IVD substructures. The objective of this study was to perform a multiscale and multimodal analysis of human lumbar motion segments across various length scales and degrees of degeneration. We performed multiple assays on every sample and identified several correlations between structural and functional measurements of disc subcomponents. Our results demonstrate that with increasing Pfirrmann grade there is a reduction in disc height and nucleus pulposus T2 relaxation time, in addition to alterations in motion segment macromechanical function, disc matrix composition and cellular morphology. At the cartilage endplate-vertebral bone interface, substantial remodeling was observed coinciding with alterations in micromechanical properties. Finally, we report significant relationships between vertebral bone and nucleus pulposus metrics, as well as between micromechanical properties of the endplate and whole motion segment biomechanical parameters, indicating the importance of studying IVD degeneration as a whole organ.
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Affiliation(s)
- Beth G Ashinsky
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA.,Drexel University School of Biomedical Engineering, Science and Health Systems, Philadelphia, PA, USA.,Translational Musculoskeletal Research Center, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, USA
| | - Sarah E Gullbrand
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA.,Translational Musculoskeletal Research Center, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, USA
| | - Chao Wang
- Drexel University School of Biomedical Engineering, Science and Health Systems, Philadelphia, PA, USA
| | - Edward D Bonnevie
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA.,Translational Musculoskeletal Research Center, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, USA
| | - Lin Han
- Drexel University School of Biomedical Engineering, Science and Health Systems, Philadelphia, PA, USA
| | - Robert L Mauck
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA.,Translational Musculoskeletal Research Center, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, USA
| | - Harvey E Smith
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA.,Translational Musculoskeletal Research Center, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, USA
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8
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LeVasseur CM, Wawrose R, Pitcairn S, Donaldson WF, Lee JY, Anderst WJ. Dynamic functional nucleus is a potential biomarker for structural degeneration in cervical spine discs. J Orthop Res 2019; 37:965-971. [PMID: 30747456 DOI: 10.1002/jor.24252] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 02/05/2019] [Indexed: 02/04/2023]
Abstract
If intervertebral disc degeneration can be identified early, preventative treatments may be initiated before symptoms become disabling and costly. Changes in disc mechanics, such as the decrease in the compressive modulus of the nucleus, are some of the earliest signs of degeneration. Therefore, in vivo changes in the disc response to compressive load may serve as a biomarker for pending or early disc degeneration. The aim of this study was to assess the potential for using in vivo dynamic disc deformation to identify pathologic structural degeneration of the intervertebral disc. A validated model-based tracking technique determined vertebral motion from biplane radiographs collected during dynamic flexion/extension and axial rotation of the cervical spine. A computational model of the subaxial intervertebral discs was developed to identify the dynamic functional nucleus of each disc, that is, the disc region that underwent little to no additional compression during dynamic movements. The size and location of the dynamic functional nucleus was determined for 10 C5/C6 spondylosis patients, 10 C5/C6/C7 spondylosis patients, and 10 asymptomatic controls. The dynamic functional nucleus size was sensitive (significantly smaller than controls in 5 of 6 measurements at the diseased disc) and specific (no difference from controls in 9 of 10 measurements at non-diseased discs) to pathologic disc degeneration. These results provide evidence to suggest that structural disc degeneration, manifested by changes in the disc response to functional loading, may be identified in vivo from dynamic imaging collected during functional movements. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 9999:1-7, 2019.
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Affiliation(s)
- Clarissa M LeVasseur
- Department of Orthopedic Surgery, University of Pittsburgh, 3820 South Water Street, Pittsburgh, 15203, Pennsylvania
| | - Richard Wawrose
- Department of Orthopedic Surgery, University of Pittsburgh, 3820 South Water Street, Pittsburgh, 15203, Pennsylvania
| | - Samuel Pitcairn
- Department of Orthopedic Surgery, University of Pittsburgh, 3820 South Water Street, Pittsburgh, 15203, Pennsylvania
| | - William F Donaldson
- Department of Orthopedic Surgery, University of Pittsburgh, 3820 South Water Street, Pittsburgh, 15203, Pennsylvania
| | - Joon Y Lee
- Department of Orthopedic Surgery, University of Pittsburgh, 3820 South Water Street, Pittsburgh, 15203, Pennsylvania
| | - William J Anderst
- Department of Orthopedic Surgery, University of Pittsburgh, 3820 South Water Street, Pittsburgh, 15203, Pennsylvania
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9
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Sadeghi S, Lin CY, Cortes DH. Narrowband Shear Wave Generation Using Sinusoidally Modulated Acoustic Radiation Force. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2019; 66:264-272. [PMID: 30530360 DOI: 10.1109/tuffc.2018.2884847] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Most transient ultrasound elastography methods use high-intensity ultrasound "push" pulses that generate a shear wave with a wide frequency spectrum. However, it is difficult to control how the energy of the wave is distributed within that spectrum. For this reason, the shear-wave group velocity may not match that of harmonic methods like magnetic resonance elastography (MRE). The objective of this study was to introduce a narrowband shear wave generation method produced by "push" pulses with sinusoidally modulated intensity. The method, named harmonic shear wave imaging (HSWI), successively transmits a series of push pulses with a periodic change in duration. The excited shear waves form a continuous shear wave with a known main frequency that can be controlled by the user. Push pulses are interleaved with imaging pulses so only one clinical transducer is used to generate and record the shear waves. The proposed method was compared to MRE and a transient shear wave elastography method using phantoms and in vivo measurements. It was found that HSWI produces narrowband waves with a speed that closely matches that measured by MRE. Measurement of the acoustic output parameters indicated that the acoustic intensities in HSWI are suitable for clinical applications. The ability of HSWI to generate narrowband shear waves using a single linear array transducer makes it amenable for clinical translation. HSWI can potentially use the same thresholds as MRE for diagnosis of diseases affecting the stiffness of soft tissues.
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10
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Smith LJ, Silverman L, Sakai D, Le Maitre CL, Mauck RL, Malhotra NR, Lotz JC, Buckley CT. Advancing cell therapies for intervertebral disc regeneration from the lab to the clinic: Recommendations of the ORS spine section. JOR Spine 2018; 1:e1036. [PMID: 30895277 PMCID: PMC6419951 DOI: 10.1002/jsp2.1036] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 09/09/2018] [Accepted: 09/10/2018] [Indexed: 12/28/2022] Open
Abstract
Intervertebral disc degeneration is strongly associated with chronic low back pain, a leading cause of disability worldwide. Current back pain treatment approaches (both surgical and conservative) are limited to addressing symptoms, not necessarily the root cause. Not surprisingly therefore, long-term efficacy of most approaches is poor. Cell-based disc regeneration strategies have shown promise in preclinical studies, and represent a relatively low-risk, low-cost, and durable therapeutic approach suitable for a potentially large patient population, thus making them attractive from both clinical and commercial standpoints. Despite such promise, no such therapies have been broadly adopted clinically. In this perspective we highlight primary obstacles and provide recommendations to help accelerate successful clinical translation of cell-based disc regeneration therapies. The key areas addressed include: (a) Optimizing cell sources and delivery techniques; (b) Minimizing potential risks to patients; (c) Selecting physiologically and clinically relevant efficacy metrics; (d) Maximizing commercial potential; and (e) Recognizing the importance of multidisciplinary collaborations and engaging with clinicians from inception through to clinical trials.
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Affiliation(s)
- Lachlan J. Smith
- Department of NeurosurgeryUniversity of PennsylvaniaPhiladelphiaPennsylvania
- Department of Orthopaedic SurgeryUniversity of PennsylvaniaPhiladelphiaPennsylvania
- Translational Musculoskeletal Research CenterCorporal Michael J. Crescenz VA Medical CenterPhiladelphiaPennsylvania
| | - Lara Silverman
- DiscGenics Inc.Salt Lake CityUtah
- Department of NeurosurgeryUniversity of Tennessee Health Science CenterMemphisTennessee
| | - Daisuke Sakai
- Department of Orthopaedic Surgery, Surgical ScienceTokai University School of MedicineIseharaJapan
| | | | - Robert L. Mauck
- Department of Orthopaedic SurgeryUniversity of PennsylvaniaPhiladelphiaPennsylvania
- Translational Musculoskeletal Research CenterCorporal Michael J. Crescenz VA Medical CenterPhiladelphiaPennsylvania
- Department of BioengineeringUniversity of PennsylvaniaPhiladelphiaPennsylvania
| | - Neil R. Malhotra
- Department of NeurosurgeryUniversity of PennsylvaniaPhiladelphiaPennsylvania
| | - Jeffrey C. Lotz
- Department of Orthopaedic SurgeryUniversity of CaliforniaSan FranciscoCalifornia
| | - Conor T. Buckley
- Trinity Centre for BioengineeringTrinity Biomedical Sciences Institute, Trinity College Dublin, The University of DublinDublinIreland
- School of EngineeringTrinity College Dublin, The University of DublinDublinIreland
- Advanced Materials and Bioengineering Research (AMBER) CentreRoyal College of Surgeons in Ireland & Trinity College Dublin, The University of DublinDublinIreland
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11
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Beauchemin PF, Bayly PV, Garbow JR, Schmidt JLS, Okamoto RJ, Chériet F, Périé D. Frequency-dependent shear properties of annulus fibrosus and nucleus pulposus by magnetic resonance elastography. NMR IN BIOMEDICINE 2018; 31:e3918. [PMID: 29727498 DOI: 10.1002/nbm.3918] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 12/23/2017] [Accepted: 02/15/2018] [Indexed: 05/22/2023]
Abstract
Aging and degeneration are associated with changes in mechanical properties in the intervertebral disc, generating interest in the establishment of mechanical properties as early biomarkers for the degenerative cascade. Magnetic resonance elastography (MRE) of the intervertebral disc is usually limited to the nucleus pulposus, as the annulus fibrosus is stiffer and less hydrated. The objective of this work was to adapt high-frequency needle MRE to the characterization of the shear modulus of both the nucleus pulposus and annulus fibrosus. Bovine intervertebral discs were removed from fresh oxtails and characterized by needle MRE. The needle was inserted in the center of the disc and vibrations were generated by an amplified piezoelectric actuator. MRE acquisitions were performed on a 4.7-T small-animal MR scanner using a spin echo sequence with sinusoidal motion encoding gradients. Acquisitions were repeated over a frequency range of 1000-1800 Hz. The local frequency estimation inversion algorithm was used to compute the shear modulus. Stiffness maps allowed the visualization of the soft nucleus pulposus surrounded by the stiffer annulus fibrosus surrounded by the homogeneous gel. A significant difference in shear modulus between the nucleus pulposus and annulus fibrosus, and an increase in the shear modulus with excitation frequency, were observed, in agreement with the literature. This study demonstrates that global characterization of both the nucleus pulposus and annulus fibrosus of the intervertebral disc is possible with needle MRE using a preclinical magnetic resonance imaging (MRI) scanner. MRE can be a powerful method for the mapping of the complex properties of the intervertebral disc. The developed method could be adapted for in situ use by preserving adjacent vertebrae and puncturing the side of the intervertebral disc, thereby allowing an assessment of the contribution of osmotic pressure to the mechanical behavior of the intervertebral disc.
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Affiliation(s)
- P F Beauchemin
- Mechanical Engineering, Polytechnique de Montréal, Montréal, QC, Canada
| | - P V Bayly
- Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO, USA
| | - J R Garbow
- Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, MO, USA
| | - J L S Schmidt
- Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO, USA
| | - R J Okamoto
- Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO, USA
| | - F Chériet
- Mechanical Engineering, Polytechnique de Montréal, Montréal, QC, Canada
- Research Center, CHU Sainte-Justine, Montréal, QC, Canada
| | - D Périé
- Mechanical Engineering, Polytechnique de Montréal, Montréal, QC, Canada
- Research Center, CHU Sainte-Justine, Montréal, QC, Canada
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Zanjani-Pour S, Meakin JR, Breen A, Breen A. Estimation of in vivo inter-vertebral loading during motion using fluoroscopic and magnetic resonance image informed finite element models. J Biomech 2018; 70:134-139. [DOI: 10.1016/j.jbiomech.2017.09.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 08/23/2017] [Accepted: 09/25/2017] [Indexed: 11/30/2022]
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Shear-wave elastography can evaluate annulus fibrosus alteration in adolescent scoliosis. Eur Radiol 2018; 28:2830-2837. [DOI: 10.1007/s00330-018-5309-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 12/06/2017] [Accepted: 01/03/2018] [Indexed: 01/19/2023]
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Walter BA, Mageswaran P, Mo X, Boulter DJ, Mashaly H, Nguyen XV, Prevedello LM, Thoman W, Raterman BD, Kalra P, Mendel E, Marras WS, Kolipaka A. MR Elastography-derived Stiffness: A Biomarker for Intervertebral Disc Degeneration. Radiology 2017; 285:167-175. [PMID: 28471737 DOI: 10.1148/radiol.2017162287] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Purpose To determine the repeatability of magnetic resonance (MR) elastography-derived shear stiffness measurements of the intervertebral disc (IVD) taken throughout the day and their relationship with IVD degeneration and subject age. Materials and Methods In a cross-sectional study, in vivo lumbar MR elastography was performed once in the morning and once in the afternoon in 47 subjects without current low back pain (IVDs = 230; age range, 20-71 years) after obtaining written consent under approval of the institutional review board. The Pfirrmann degeneration grade and MR elastography-derived shear stiffness of the nucleus pulposus and annulus fibrosus regions of all lumbar IVDs were assessed by means of principal frequency analysis. One-way analysis of variance, paired t tests, concordance and Bland-Altman tests, and Pearson correlations were used to evaluate degeneration, diurnal changes, repeatability, and age effects, respectively. Results There were no significant differences between morning and afternoon shear stiffness across all levels and there was very good technical repeatability between the morning and afternoon imaging results for both nucleus pulposus (R = 0.92) and annulus fibrosus (R = 0.83) regions. There was a significant increase in both nucleus pulposus and annulus fibrosus MR elastography-derived shear stiffness with increasing Pfirrmann degeneration grade (nucleus pulposus grade 1, 12.5 kPa ± 1.3; grade 5, 16.5 kPa ± 2.1; annulus fibrosus grade 1, 90.4 kPa ± 9.3; grade 5, 120.1 kPa ± 15.4), and there were weak correlations between shear stiffness and age across all levels (R ≤ 0.32). Conclusion Our results demonstrate that MR elastography-derived shear stiffness measurements are highly repeatable, weakly correlate with age, and increase with advancing IVD degeneration. These results suggest that MR elastography-derived shear stiffness may provide an objective biomarker of the IVD degeneration process. © RSNA, 2017 Online supplemental material is available for this article.
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Affiliation(s)
- Benjamin A Walter
- From the Spine Research Institute (B.A.W., P.M., H.M., W.T., E.M., W.S.M., A.K.), Department of Biomedical Engineering (B.A.W., A.K.), Department of Integrated Systems Engineering (P.M., W.S.M.), and Department of Biomedical Informatics (X.M.), the Ohio State University, 395 W 12th Ave, 4th Floor Radiology, Columbus, OH 43210; and Departments of Radiology (D.J.B., X.V.N., L.M.P., B.D.R., P.K., A.K.) and Neurologic Surgery (H.M., W.T., E.M.), the Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Prasath Mageswaran
- From the Spine Research Institute (B.A.W., P.M., H.M., W.T., E.M., W.S.M., A.K.), Department of Biomedical Engineering (B.A.W., A.K.), Department of Integrated Systems Engineering (P.M., W.S.M.), and Department of Biomedical Informatics (X.M.), the Ohio State University, 395 W 12th Ave, 4th Floor Radiology, Columbus, OH 43210; and Departments of Radiology (D.J.B., X.V.N., L.M.P., B.D.R., P.K., A.K.) and Neurologic Surgery (H.M., W.T., E.M.), the Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Xiaokui Mo
- From the Spine Research Institute (B.A.W., P.M., H.M., W.T., E.M., W.S.M., A.K.), Department of Biomedical Engineering (B.A.W., A.K.), Department of Integrated Systems Engineering (P.M., W.S.M.), and Department of Biomedical Informatics (X.M.), the Ohio State University, 395 W 12th Ave, 4th Floor Radiology, Columbus, OH 43210; and Departments of Radiology (D.J.B., X.V.N., L.M.P., B.D.R., P.K., A.K.) and Neurologic Surgery (H.M., W.T., E.M.), the Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Daniel J Boulter
- From the Spine Research Institute (B.A.W., P.M., H.M., W.T., E.M., W.S.M., A.K.), Department of Biomedical Engineering (B.A.W., A.K.), Department of Integrated Systems Engineering (P.M., W.S.M.), and Department of Biomedical Informatics (X.M.), the Ohio State University, 395 W 12th Ave, 4th Floor Radiology, Columbus, OH 43210; and Departments of Radiology (D.J.B., X.V.N., L.M.P., B.D.R., P.K., A.K.) and Neurologic Surgery (H.M., W.T., E.M.), the Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Hazem Mashaly
- From the Spine Research Institute (B.A.W., P.M., H.M., W.T., E.M., W.S.M., A.K.), Department of Biomedical Engineering (B.A.W., A.K.), Department of Integrated Systems Engineering (P.M., W.S.M.), and Department of Biomedical Informatics (X.M.), the Ohio State University, 395 W 12th Ave, 4th Floor Radiology, Columbus, OH 43210; and Departments of Radiology (D.J.B., X.V.N., L.M.P., B.D.R., P.K., A.K.) and Neurologic Surgery (H.M., W.T., E.M.), the Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Xuan V Nguyen
- From the Spine Research Institute (B.A.W., P.M., H.M., W.T., E.M., W.S.M., A.K.), Department of Biomedical Engineering (B.A.W., A.K.), Department of Integrated Systems Engineering (P.M., W.S.M.), and Department of Biomedical Informatics (X.M.), the Ohio State University, 395 W 12th Ave, 4th Floor Radiology, Columbus, OH 43210; and Departments of Radiology (D.J.B., X.V.N., L.M.P., B.D.R., P.K., A.K.) and Neurologic Surgery (H.M., W.T., E.M.), the Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Luciano M Prevedello
- From the Spine Research Institute (B.A.W., P.M., H.M., W.T., E.M., W.S.M., A.K.), Department of Biomedical Engineering (B.A.W., A.K.), Department of Integrated Systems Engineering (P.M., W.S.M.), and Department of Biomedical Informatics (X.M.), the Ohio State University, 395 W 12th Ave, 4th Floor Radiology, Columbus, OH 43210; and Departments of Radiology (D.J.B., X.V.N., L.M.P., B.D.R., P.K., A.K.) and Neurologic Surgery (H.M., W.T., E.M.), the Ohio State University Wexner Medical Center, Columbus, Ohio
| | - William Thoman
- From the Spine Research Institute (B.A.W., P.M., H.M., W.T., E.M., W.S.M., A.K.), Department of Biomedical Engineering (B.A.W., A.K.), Department of Integrated Systems Engineering (P.M., W.S.M.), and Department of Biomedical Informatics (X.M.), the Ohio State University, 395 W 12th Ave, 4th Floor Radiology, Columbus, OH 43210; and Departments of Radiology (D.J.B., X.V.N., L.M.P., B.D.R., P.K., A.K.) and Neurologic Surgery (H.M., W.T., E.M.), the Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Brian D Raterman
- From the Spine Research Institute (B.A.W., P.M., H.M., W.T., E.M., W.S.M., A.K.), Department of Biomedical Engineering (B.A.W., A.K.), Department of Integrated Systems Engineering (P.M., W.S.M.), and Department of Biomedical Informatics (X.M.), the Ohio State University, 395 W 12th Ave, 4th Floor Radiology, Columbus, OH 43210; and Departments of Radiology (D.J.B., X.V.N., L.M.P., B.D.R., P.K., A.K.) and Neurologic Surgery (H.M., W.T., E.M.), the Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Prateek Kalra
- From the Spine Research Institute (B.A.W., P.M., H.M., W.T., E.M., W.S.M., A.K.), Department of Biomedical Engineering (B.A.W., A.K.), Department of Integrated Systems Engineering (P.M., W.S.M.), and Department of Biomedical Informatics (X.M.), the Ohio State University, 395 W 12th Ave, 4th Floor Radiology, Columbus, OH 43210; and Departments of Radiology (D.J.B., X.V.N., L.M.P., B.D.R., P.K., A.K.) and Neurologic Surgery (H.M., W.T., E.M.), the Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Ehud Mendel
- From the Spine Research Institute (B.A.W., P.M., H.M., W.T., E.M., W.S.M., A.K.), Department of Biomedical Engineering (B.A.W., A.K.), Department of Integrated Systems Engineering (P.M., W.S.M.), and Department of Biomedical Informatics (X.M.), the Ohio State University, 395 W 12th Ave, 4th Floor Radiology, Columbus, OH 43210; and Departments of Radiology (D.J.B., X.V.N., L.M.P., B.D.R., P.K., A.K.) and Neurologic Surgery (H.M., W.T., E.M.), the Ohio State University Wexner Medical Center, Columbus, Ohio
| | - William S Marras
- From the Spine Research Institute (B.A.W., P.M., H.M., W.T., E.M., W.S.M., A.K.), Department of Biomedical Engineering (B.A.W., A.K.), Department of Integrated Systems Engineering (P.M., W.S.M.), and Department of Biomedical Informatics (X.M.), the Ohio State University, 395 W 12th Ave, 4th Floor Radiology, Columbus, OH 43210; and Departments of Radiology (D.J.B., X.V.N., L.M.P., B.D.R., P.K., A.K.) and Neurologic Surgery (H.M., W.T., E.M.), the Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Arunark Kolipaka
- From the Spine Research Institute (B.A.W., P.M., H.M., W.T., E.M., W.S.M., A.K.), Department of Biomedical Engineering (B.A.W., A.K.), Department of Integrated Systems Engineering (P.M., W.S.M.), and Department of Biomedical Informatics (X.M.), the Ohio State University, 395 W 12th Ave, 4th Floor Radiology, Columbus, OH 43210; and Departments of Radiology (D.J.B., X.V.N., L.M.P., B.D.R., P.K., A.K.) and Neurologic Surgery (H.M., W.T., E.M.), the Ohio State University Wexner Medical Center, Columbus, Ohio
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Rivers WE, Rimmalapudi V, Heit JJ. Progress in Advanced Imaging Techniques for the Lumbar Spine. CURRENT PHYSICAL MEDICINE AND REHABILITATION REPORTS 2016. [DOI: 10.1007/s40141-016-0114-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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16
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Image driven subject-specific finite element models of spinal biomechanics. J Biomech 2016; 49:919-925. [DOI: 10.1016/j.jbiomech.2016.02.025] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 02/04/2016] [Accepted: 02/05/2016] [Indexed: 11/20/2022]
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DeLucca JF, Cortes DH, Jacobs NT, Vresilovic EJ, Duncan RL, Elliott DM. Human cartilage endplate permeability varies with degeneration and intervertebral disc site. J Biomech 2016; 49:550-7. [PMID: 26874969 DOI: 10.1016/j.jbiomech.2016.01.007] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 01/07/2016] [Accepted: 01/08/2016] [Indexed: 01/08/2023]
Abstract
Despite the critical functions the human cartilage endplate (CEP) plays in the intervertebral disc, little is known about its structural and mechanical properties and their changes with degeneration. Quantifying these changes with degeneration is important for understanding how the CEP contributes to the function and pathology of the disc. Therefore the objectives of this study were to quantify the effect of disc degeneration on human CEP mechanical properties, determine the influence of superior and inferior disc site on mechanics and composition, and simulate the role of collagen fibers in CEP and disc mechanics using a validated finite element model. Confined compression data and biochemical composition data were used in a biphasic-swelling model to calculate compressive extrafibrillar elastic and permeability properties. Tensile properties were obtained by applying published tensile test data to an ellipsoidal fiber distribution. Results showed that with degeneration CEP permeability decreased 50-60% suggesting that transport is inhibited in the degenerate disc. CEP fibers are organized parallel to the vertebrae and nucleus pulposus and may contribute to large shear strains (0.1-0.2) and delamination failure of the CEP commonly seen in herniated disc tissue. Fiber-reinforcement also reduces CEP axial strains thereby enhancing fluid flux by a factor of 1.8. Collectively, these results suggest that the structure and mechanics of the CEP may play critical roles in the solute transport and disc mechanics.
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Affiliation(s)
- John F DeLucca
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States
| | - Daniel H Cortes
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States
| | - Nathan T Jacobs
- Department of Mechanical Engineering, University of Pennsylvania, Philadelphia, PA, United States
| | - Edward J Vresilovic
- Penn State Hershey Bone and Joint Institute Pennsylvania State University, Hershey, PA, United States
| | - Randall L Duncan
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States; Department of Biological Sciences, University of Delaware, Newark, DE, United States
| | - Dawn M Elliott
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States.
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18
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Ben-Abraham EI, Chen J, Felmlee JP, Rossman P, Manduca A, An KN, Ehman RL. Feasibility of MR elastography of the intervertebral disc. Magn Reson Imaging 2015; 39:132-137. [PMID: 26743429 DOI: 10.1016/j.mri.2015.12.037] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 12/27/2015] [Indexed: 01/07/2023]
Abstract
Low back pain (LBP) is a costly and widely prevalent health disorder in the U.S. One of the most common causes of LBP is degenerative disc disease (DDD). There are many imaging techniques to characterize disc degeneration; however, there is no way to directly assess the material properties of the intervertebral disc (IVD) within the intact spine. Magnetic resonance elastography (MRE) is an MRI-based technique for non-invasively mapping the mechanical properties of tissues in vivo. The purpose of this study was to investigate the feasibility of using MRE to detect shear wave propagation in and determine the shear stiffness of an axial cross-section of an ex vivo baboon IVD, and compare with shear displacements from a finite element model of an IVD motion segment in response to harmonic shear vibration. MRE was performed on two baboon lumbar spine motion segments (L3-L4) with the posterior elements removed at a range of frequencies (1000-1500Hz) using a standard clinical 1.5T MR scanner. Propagating waves were visualized in an axial cross-section of the baboon IVDs in all three motion-encoding directions, which resembled wave patterns predicted using finite element modeling. The baboon nucleus pulposus showed an average shear stiffness of 79±15kPa at 1000Hz. These results suggest that MRE is capable of visualizing shear wave propagation in the IVD, assessing the stiffness of the nucleus of the IVD, and can differentiate the nucleus and annulus regions.
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Affiliation(s)
- Ephraim I Ben-Abraham
- Mayo Graduate School, Biomedical Engineering and Physiology Track, Mayo Clinic, Rochester, Minnesota, USA.
| | - Jun Chen
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
| | - Joel P Felmlee
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
| | - Phil Rossman
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
| | - Armando Manduca
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
| | - Kai-Nan An
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA.
| | - Richard L Ehman
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
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Vergari C, Dubois G, Vialle R, Gennisson JL, Tanter M, Dubousset J, Rouch P, Skalli W. Lumbar annulus fibrosus biomechanical characterization in healthy children by ultrasound shear wave elastography. Eur Radiol 2015. [PMID: 26198667 DOI: 10.1007/s00330-015-3911-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVES Intervertebral disc (IVD) is key to spine biomechanics, and it is often involved in the cascade leading to spinal deformities such as idiopathic scoliosis, especially during the growth spurt. Recent progress in elastography techniques allows access to non-invasive measurement of cervical IVD in adults; the aim of this study was to determine the feasibility and reliability of shear wave elastography in healthy children lumbar IVD. METHODS Elastography measurements were performed in 31 healthy children (6-17 years old), in the annulus fibrosus and in the transverse plane of L5-S1 or L4-L5 IVD. Reliability was determined by three experienced operators repeating measurements. RESULTS Average shear wave speed in IVD was 2.9 ± 0.5 m/s; no significant correlations were observed with sex, age or body morphology. Intra-operator repeatability was 5.0 % while inter-operator reproducibility was 6.2 %. Intraclass correlation coefficient was higher than 0.9 for each operator. CONCLUSIONS Feasibility and reliability of IVD shear wave elastography were demonstrated. The measurement protocol is compatible with clinical routine and the results show the method's potential to give an insight into spine deformity progression and early detection. KEY POINTS • Intervertebral disc mechanical properties are key to spine biomechanics • Feasibility of shear wave elastography in children lumbar disc was assessed • Measurement was fast and reliable • Elastography could represent a novel biomarker for spine pathologies.
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Affiliation(s)
- Claudio Vergari
- Arts et Metiers ParisTech, LBM/Institut de Biomecanique Humaine Georges Charpak, 151 bd de l'Hopital, 75013, Paris, France.
| | - Guillaume Dubois
- Arts et Metiers ParisTech, LBM/Institut de Biomecanique Humaine Georges Charpak, 151 bd de l'Hopital, 75013, Paris, France
| | - Raphael Vialle
- Department of Paediatric Orthopaedics, Armand Trousseau Hospital, Université Pierre et Marie Curie-Paris 6, 75571, Paris, France
| | - Jean-Luc Gennisson
- Institut Langevin, Ondes et Images, ESPCI ParisTech, CNRS UMR7587, INSERM U979, Paris, France
| | - Mickael Tanter
- Institut Langevin, Ondes et Images, ESPCI ParisTech, CNRS UMR7587, INSERM U979, Paris, France
| | - Jean Dubousset
- Arts et Metiers ParisTech, LBM/Institut de Biomecanique Humaine Georges Charpak, 151 bd de l'Hopital, 75013, Paris, France
| | - Philippe Rouch
- Arts et Metiers ParisTech, LBM/Institut de Biomecanique Humaine Georges Charpak, 151 bd de l'Hopital, 75013, Paris, France
| | - Wafa Skalli
- Arts et Metiers ParisTech, LBM/Institut de Biomecanique Humaine Georges Charpak, 151 bd de l'Hopital, 75013, Paris, France
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Cortes DH, Suydam SM, Silbernagel KG, Buchanan TS, Elliott DM. Continuous Shear Wave Elastography: A New Method to Measure Viscoelastic Properties of Tendons in Vivo. ULTRASOUND IN MEDICINE & BIOLOGY 2015; 41:1518-29. [PMID: 25796414 PMCID: PMC4426016 DOI: 10.1016/j.ultrasmedbio.2015.02.001] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 01/27/2015] [Accepted: 02/04/2015] [Indexed: 05/09/2023]
Abstract
Viscoelastic mechanical properties are frequently altered after tendon injuries and during recovery. Therefore, non-invasive measurements of shear viscoelastic properties may help evaluate tendon recovery and compare the effectiveness of different therapies. The objectives of this study were to describe an elastography method for measuring localized viscoelastic properties of tendons and to discuss the initial results in healthy and injured human Achilles and semitendinosus tendons. The technique used an external actuator to generate the shear waves in the tendon at different frequencies and plane wave imaging to measure shear wave displacements. For each of the excitation frequencies, maps of direction-specific wave speeds were calculated using local frequency estimation. Maps of viscoelastic properties were obtained using a pixel-wise curve fit of wave speed and frequency. The method was validated by comparing measurements of wave speed in agarose gels with those obtained using magnetic resonance elastography. Measurements in human healthy Achilles tendons revealed a pronounced increase in wave speed as a function of frequency, which highlights the importance of tendon viscoelasticity. Additionally, the viscoelastic properties of the Achilles tendon were larger than those reported for other tissues. Measurements in a tendinopathic Achilles tendon indicated that it is feasible to quantify local viscoelastic properties. Similarly, measurement in the semitendinosus tendon revealed substantial differences in viscoelastic properties between the healthy and contralateral tendons. Consequently, this technique has the potential to evaluate localized changes in tendon viscoelastic properties caused by injury and during recovery in a clinical setting.
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Affiliation(s)
- Daniel H Cortes
- Biomedical Engineering Program, University of Delaware, Newark, Delaware, USA.
| | - Stephen M Suydam
- Mechanical Engineering Department, University of Delaware, Newark, Delaware, USA
| | | | - Thomas S Buchanan
- Mechanical Engineering Department, University of Delaware, Newark, Delaware, USA
| | - Dawn M Elliott
- Biomedical Engineering Program, University of Delaware, Newark, Delaware, USA
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Developments in intervertebral disc disease research: pathophysiology, mechanobiology, and therapeutics. Curr Rev Musculoskelet Med 2015; 8:18-31. [PMID: 25694233 DOI: 10.1007/s12178-014-9253-8] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Low back pain is a leading cause of disability worldwide and the second most common cause of physician visits. There are many causes of back pain, and among them, disc herniation and intervertebral disc degeneration are the most common diagnoses and targets for intervention. Currently, clinical treatment outcomes are not strongly correlated with diagnoses, emphasizing the importance for characterizing more completely the mechanisms of degeneration and their relationships with symptoms. This review covers recent studies elucidating cellular and molecular changes associated with disc mechanobiology, as it relates to degeneration and regeneration. Specifically, we review findings on the biochemical changes in disc diseases, including cytokines, chemokines, and proteases; advancements in disc disease diagnostics using imaging modalities; updates on studies examining the response of the intervertebral disc to injury; and recent developments in repair strategies, including cell-based repair, biomaterials, and tissue engineering. Findings on the effects of the omega-6 fatty acid, linoleic acid, on nucleus pulposus tissue engineering are presented. Studies described in this review provide greater insights into the pathogenesis of disc degeneration and may define new paradigms for early or differential diagnostics of degeneration using new techniques such as systemic biomarkers. In addition, research on the mechanobiology of disease enriches the development of therapeutics for disc repair, with potential to diminish pain and disability associated with disc degeneration.
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Magland JF, Li C, Langham MC, Wehrli FW. Pulse sequence programming in a dynamic visual environment: SequenceTree. Magn Reson Med 2015; 75:257-65. [PMID: 25754837 DOI: 10.1002/mrm.25640] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 12/09/2014] [Accepted: 01/07/2015] [Indexed: 01/04/2023]
Abstract
PURPOSE To describe SequenceTree, an open source, integrated software environment for implementing MRI pulse sequences and, ideally, exporting them to actual MRI scanners. The software is a user-friendly alternative to vendor-supplied pulse sequence design and editing tools and is suited for programmers and nonprogrammers alike. METHODS The integrated user interface was programmed using the Qt4/C++ toolkit. As parameters and code are modified, the pulse sequence diagram is automatically updated within the user interface. Several aspects of pulse programming are handled automatically, allowing users to focus on higher-level aspects of sequence design. Sequences can be simulated using a built-in Bloch equation solver and then exported for use on a Siemens MRI scanner. Ideally, other types of scanners will be supported in the future. RESULTS SequenceTree has been used for 8 years in our laboratory and elsewhere and has contributed to more than 50 peer-reviewed publications in areas such as cardiovascular imaging, solid state and nonproton NMR, MR elastography, and high-resolution structural imaging. CONCLUSION SequenceTree is an innovative, open source, visual pulse sequence environment for MRI combining simplicity with flexibility and is ideal both for advanced users and users with limited programming experience.
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Affiliation(s)
- Jeremy F Magland
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Cheng Li
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Michael C Langham
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Felix W Wehrli
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, 19104, USA
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23
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Streitberger KJ, Diederichs G, Guo J, Fehlner A, Hamm B, Braun J, Sack I. In vivo multifrequency magnetic resonance elastography of the human intervertebral disk. Magn Reson Med 2014; 74:1380-7. [PMID: 25359242 DOI: 10.1002/mrm.25505] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 09/30/2014] [Accepted: 10/06/2014] [Indexed: 01/07/2023]
Abstract
PURPOSE To test in vivo magnetic resonance elastography (MRE) of the human intervertebral disk (IVD). METHODS The feasibility of MRE in IVD was demonstrated in ex vivo bovine disks. Sixteen asymptomatic volunteers underwent multifrequency MRE of the lumbar spine (IVD L3/4 and L4/5, n = 32) using a posterior plate transducer connected to a loudspeaker and operated at five frequencies from 50 to 70 Hz. Full wave field data were acquired in 10 transverse slices of 2 × 2 × 2 mm(3) resolution. High-resolution maps of magnitude |G*| and phase angle φ of complex shear modulus G* were generated by multifrequency dual elasto visco (MDEV) inversion. Disk morphology was assessed by the Pfirrmann score (Pf). RESULTS Morphological Pf was 1 in 25, 2 in 3, and 3 in 4 disks. |G*| decreased with Pf by a Pearson's linear correlation coefficient of R = -0.592 (P = 0.0004), while φ remained unchanged. Group mean mechanical parameters for Pf = 1 to 3 were |G*| = 6.51 ± 1.27, 5.29 ± 0.95, 4.03 ± 0.99 kPa, and φ = 1.190 ± 0.181, 1.170 ± 0.156, 1.088 ± 0.084 rad, respectively (p[Pf1-Pf3] < 0.001). The variability of mechanical parameters in one volunteer including diurnal changes was approximately 11%. CONCLUSION Multifrequency MRE with MDEV inversion allows measurement of in vivo mechanical properties of IVDs and may provide additional information in disc degeneration beyond standard morphological changes.
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Affiliation(s)
| | - Gerd Diederichs
- Department of Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Jing Guo
- Department of Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Andreas Fehlner
- Department of Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Bernd Hamm
- Department of Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Jürgen Braun
- Institute of Medical Informatics, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Ingolf Sack
- Department of Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
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24
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Non-invasive biomechanical characterization of intervertebral discs by shear wave ultrasound elastography: a feasibility study. Eur Radiol 2014; 24:3210-6. [PMID: 25120207 DOI: 10.1007/s00330-014-3382-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 07/08/2014] [Accepted: 07/31/2014] [Indexed: 12/16/2022]
Abstract
OBJECTIVES Although magnetic resonance is widely spread to assess qualitatively disc morphology, a simple method to determine reliably intervertebral disc status is still lacking. Shear wave elastography is a novel technique that allows quantitative evaluation of soft-tissues' mechanical properties. The aim of this study was to assess preliminary the feasibility and reliability of mechanical characterization of cervical intervertebral discs by elastography and to provide first reference values for asymptomatic subjects. METHODS Elastographic measurements were performed to determine shear wave speed (SWS) in C6-C7 or C7-T1 disc of 47 subjects; repeatability and inter-operator reproducibility were assessed. RESULTS Global average shear wave speed (SWS) was 3.0 ± 0.4 m/s; measurement repeatability and inter-user reproducibility were 7 and 10%, respectively. SWS was correlated with both subject's age (p = 1.3 × 10(-5)) and body mass index (p = 0.008). CONCLUSIONS Shear wave elastography in intervertebral discs proved reliable and allowed stratification of subjects according to age and BMI. Applications could be relevant, for instance, in early detection of disc degeneration or in follow-up after trauma; these results open the way to larger cohort studies to define the place of this technique in routine intervertebral disc assessment. KEY POINTS A simple method to obtain objectively intervertebral disc status is still lacking. Shear wave elastography was applied in vivo to assess intervertebral discs. Elastography showed promising results in biomechanical disc evaluation. Elastography could be relevant in clinical routine for intervertebral disc assessment.
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25
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Chan DD, Gossett PC, Butz KD, Nauman EA, Neu CP. Comparison of intervertebral disc displacements measured under applied loading with MRI at 3.0 T and 9.4 T. J Biomech 2014; 47:2801-6. [PMID: 24968943 DOI: 10.1016/j.jbiomech.2014.05.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 05/26/2014] [Accepted: 05/30/2014] [Indexed: 11/25/2022]
Abstract
The purpose of this study was to compare displacement behavior of cyclically loaded cadaveric human intervertebral discs as measured noninvasively on a clinical 3.0 T and a research 9.4 T MRI system. Intervertebral discs were cyclically compressed at physiologically relevant levels with the same MRI-compatible loading device in the clinical and research systems. Displacement-encoded imaging was synchronized to cyclic loading to measure displacements under applied loading with MRI (dual MRI). Displacements from the two systems were compared individually using linear regression and, across all specimens, using Bland-Altman analysis. In-plane displacement patterns measured at 3.0 T and 9.4 T were qualitatively comparable and well correlated. Bland-Altman analyses showed that over 90% of displacement values within the intervertebral disc regions of interest lay within the limits of agreement. Measurement of displacement using dual MRI using a 3.0 T clinical system is comparable to that of a 9.4 T research system. Additional refinements of software, technique implementation, and image processing have potential to improve agreement between different MRI systems. Despite differences in MRI systems in this initial implementation, this work demonstrates that dual MRI can be reliably implemented at multiple magnetic field strengths, permitting translation of dual MRI for a variety of applications in the study of tissue and biomaterial biomechanics.
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Affiliation(s)
- Deva D Chan
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Paull C Gossett
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Kent D Butz
- School of Mechanical Engineering, Purdue University, West Lafayette, IN, USA
| | - Eric A Nauman
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA; School of Mechanical Engineering, Purdue University, West Lafayette, IN, USA
| | - Corey P Neu
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA.
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