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Poulen G, Perrin FE. Advances in spinal cord injury: insights from non-human primates. Neural Regen Res 2024; 19:2354-2364. [PMID: 38526271 PMCID: PMC11090432 DOI: 10.4103/nrr.nrr-d-23-01505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 11/13/2023] [Accepted: 12/22/2023] [Indexed: 03/26/2024] Open
Abstract
Spinal cord injury results in significant sensorimotor deficits, currently, there is no curative treatment for the symptoms induced by spinal cord injury. Basic and pre-clinical research on spinal cord injury relies on the development and characterization of appropriate animal models. These models should replicate the symptoms observed in human, allowing for the exploration of functional deficits and investigation into various aspects of physiopathology of spinal cord injury. Non-human primates, due to their close phylogenetic association with humans, share more neuroanatomical, genetic, and physiological similarities with humans than rodents. Therefore, the responses to spinal cord injury in nonhuman primates most likely resemble the responses to traumatism in humans. In this review, we will discuss nonhuman primate models of spinal cord injury, focusing on in vivo assessments, including behavioral tests, magnetic resonance imaging, and electrical activity recordings, as well as ex vivo histological analyses. Additionally, we will present therapeutic strategies developed in non-human primates and discuss the unique specificities of non-human primate models of spinal cord injury.
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Affiliation(s)
- Gaetan Poulen
- University of Montpellier, INSERM, EPHE, Montpellier, France
- Department of Neurosurgery, Gui de Chauliac Hospital, Montpellier University Medical Center, Montpellier, France
| | - Florence E. Perrin
- University of Montpellier, INSERM, EPHE, Montpellier, France
- Institut Universitaire de France (IUF), Paris, France
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Tao Q, Zhang Q, An Z, Chen Z, Feng Y. Multi-Parametric MRI for Evaluating Variations in Renal Structure, Function, and Endogenous Metabolites in an Animal Model With Acute Kidney Injury Induced by Ischemia Reperfusion. J Magn Reson Imaging 2024; 60:245-255. [PMID: 37881827 DOI: 10.1002/jmri.29094] [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: 07/16/2023] [Revised: 10/12/2023] [Accepted: 10/12/2023] [Indexed: 10/27/2023] Open
Abstract
BACKGROUND Ischemia reperfusion injury (IRI)-induced acute kidney injury (AKI) may occur after renal ischemic injury. There is a lack of an accurate and comprehensive detection technique for IRI-AKI. PURPOSE To longitudinally evaluate IRI-AKI in rats by renal structure, function, and metabolites using multi-parametric MRI (mpMRI). STUDY TYPE Prospective. ANIMAL MODEL Forty-eight rats undergoing IRI-AKI. FIELD STRENGTH/SEQUENCE 7-T, T1 mapping, and arterial spin labeling (ASL): echo planar imaging (EPI) sequence; blood oxygen level-dependent (BOLD): gradient recalled echo (GRE) sequence; T2 mapping, quantitative magnetization transfer (qMT), and chemical exchange saturation transfer (CEST): rapid acquisition with relaxation enhancement (RARE) sequence. ASSESSMENT The mpMRI for IRI-AKI was conducted at 0 (control), 1, 3, 7, 14, and 28 days, all included eight rats. The longitudinal mpMRI signal of manually outlined cortex, outer stripe of the outer medulla (OSOM), inner stripe of the outer medulla, and medulla plus pelvis were calculated and compared, their diagnosis performance for IRI-AKI also been evaluated. STATISTICAL TESTS Pearson correlations analysis for correlation between mpMRI signal and renal injury, unpaired t-tests for comparing the signal changes, and receiver operating characteristics (ROC) analysis was used to identify most sensitive indicator of mpMRI. A P-value <0.05 was considered statistically significant. RESULTS Compared with control kidneys, the T1 and T2 values of the cortex and medulla in IRI kidneys increased and reached their highest values on day 14, and the kidneys also showed the most severe edema and segments blurred. The RBF in the cortex and OSOM showed a significant decline after day 3. The BOLD signal in the OSOM largest increased on day 28. The cortical PSR and the amine-CEST both decreased with IRI-AKI progression, and amine-CEST achieved the highest AUC for the diagnosis (0.899). DATA CONCLUSION Multi-parametric MRI may show comprehensive variations in IRI-AKI, and amine-CEST may exhibit the highest accuracy for diagnosis of IRI-AKI. LEVEL OF EVIDENCE 1 TECHNICAL EFFICACY: Stage 2.
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Affiliation(s)
- Quan Tao
- Department of Rehabilitation Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Medical Image Processing, Southern Medical University, Guangzhou, China
- Guangdong Provincial Engineering Laboratory for Medical Imaging and Diagnostic Technology, Southern Medical University, Guangzhou, China
| | - Qianqian Zhang
- Guangdong Provincial Key Laboratory of Medical Image Processing, Southern Medical University, Guangzhou, China
- Guangdong Provincial Engineering Laboratory for Medical Imaging and Diagnostic Technology, Southern Medical University, Guangzhou, China
- School of Biomedical Engineering, Southern Medical University, Guangzhou, China
| | - Ziqi An
- Guangdong Provincial Key Laboratory of Medical Image Processing, Southern Medical University, Guangzhou, China
- Guangdong Provincial Engineering Laboratory for Medical Imaging and Diagnostic Technology, Southern Medical University, Guangzhou, China
- School of Biomedical Engineering, Southern Medical University, Guangzhou, China
| | - Zelong Chen
- Medical Imaging Center, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Yanqiu Feng
- Department of Rehabilitation Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Medical Image Processing, Southern Medical University, Guangzhou, China
- Guangdong Provincial Engineering Laboratory for Medical Imaging and Diagnostic Technology, Southern Medical University, Guangzhou, China
- School of Biomedical Engineering, Southern Medical University, Guangzhou, China
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Mu C, Reed JL, Wang F, Tantawy MN, Gore JC, Chen LM. Spatiotemporal Dynamics of Neuroinflammation Relate to Behavioral Recovery in Rats with Spinal Cord Injury. Mol Imaging Biol 2024; 26:240-252. [PMID: 38151582 DOI: 10.1007/s11307-023-01875-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 11/03/2023] [Accepted: 11/06/2023] [Indexed: 12/29/2023]
Abstract
PURPOSE The degree and dynamic progression of neuroinflammation after traumatic spinal cord injuries (SCI) are crucial determinants of the severity of injury and potential for recovery. We used Positron Emission Tomography (PET) to monitor neuroinflammation longitudinally, correlating it with Chemical Exchange Saturation Transfer (CEST) Magnetic Resonance Imaging (MRI) and behavior in contusion-injured rats. These studies help validate CEST metrics and confirm how imaging may be used to evaluate the efficacy of therapies and understand their mechanisms of action. PROCEDURES 12 SCI and 4 sham surgery rats were subjected to CEST MRI and PET-Translocator Protein (TSPO) scans for 8 weeks following injury. Z-spectra from the SCI were analyzed using a 5-Lorentzian pool model for fitting. Weekly motor and somatosensory behavior were correlated with imaging metrics, which were validated through post-mortem histological and immuo-staining using ionized calcium-binding adaptor protein-1 (iba-1, microglia) and glial fibrillary acidic protein (GFAP, astrocytes). RESULTS PET-TSPO showed widespread inflammation and post-mortem histology confirmed the presence of activated microglia. Changes in CEST and nuclear Overhauser Effect (NOE) peaks at 3.5 ppm and -1.6 ppm respectively were largest within the first week after injury and more pronounced in rostral versus caudal segments. These temporal indices of neuroinflammation corresponded to the recovery of locomotor behaviors and somatic sensation in rats with moderate contusion injury. The results confirm that CEST MRI metrics are sensitive indices of states of neuroinflammation within injured spinal cords. CONCLUSIONS The detection of dynamic spatiotemporal features of neuroinflammation progression underscores the importance of considering their timings and locations for neuroprotective and anti-inflammatory therapies. The availability of noninvasive MRI indices of neuroinflammation may facilitate clinical trials aimed at treatments that promote recovery after SCI.
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Affiliation(s)
- Chaoqi Mu
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
| | - Jamie L Reed
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Feng Wang
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - M Noor Tantawy
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - John C Gore
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
| | - Li Min Chen
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA.
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA.
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA.
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Chen LM, Wang F, Mishra A, Yang PF, Sengupta A, Reed JL, Gore JC. Longitudinal multiparametric MRI of traumatic spinal cord injury in animal models. Magn Reson Imaging 2023; 102:184-200. [PMID: 37343904 PMCID: PMC10528214 DOI: 10.1016/j.mri.2023.06.007] [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: 03/17/2022] [Revised: 06/14/2023] [Accepted: 06/17/2023] [Indexed: 06/23/2023]
Abstract
Multi-parametric MRI (mpMRI) technology enables non-invasive and quantitative assessments of the structural, molecular, and functional characteristics of various neurological diseases. Despite the recognized importance of studying spinal cord pathology, mpMRI applications in spinal cord research have been somewhat limited, partly due to technical challenges associated with spine imaging. However, advances in imaging techniques and improved image quality now allow longitudinal investigations of a comprehensive range of spinal cord pathological features by exploiting different endogenous MRI contrasts. This review summarizes the use of mpMRI techniques including blood oxygenation level-dependent (BOLD) functional MRI (fMRI), diffusion tensor imaging (DTI), quantitative magnetization transfer (qMT), and chemical exchange saturation transfer (CEST) MRI in monitoring different aspects of spinal cord pathology. These aspects include cyst formation and axonal disruption, demyelination and remyelination, changes in the excitability of spinal grey matter and the integrity of intrinsic functional circuits, and non-specific molecular changes associated with secondary injury and neuroinflammation. These approaches are illustrated with reference to a nonhuman primate (NHP) model of traumatic cervical spinal cord injuries (SCI). We highlight the benefits of using NHP SCI models to guide future studies of human spinal cord pathology, and demonstrate how mpMRI can capture distinctive features of spinal cord pathology that were previously inaccessible. Furthermore, the development of mechanism-based MRI biomarkers from mpMRI studies can provide clinically useful imaging indices for understanding the mechanisms by which injured spinal cords progress and repair. These biomarkers can assist in the diagnosis, prognosis, and evaluation of therapies for SCI patients, potentially leading to improved outcomes.
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Affiliation(s)
- Li Min Chen
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA.
| | - Feng Wang
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Arabinda Mishra
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Pai-Feng Yang
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Anirban Sengupta
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Jamie L Reed
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - John C Gore
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
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Lu M, Drake G, Wang F, Mu C, Chen LM, Gore JC, Yan X. Design and construction of an interchangeable RF coil system for rodent spinal cord MR imaging at 9.4 T. Magn Reson Imaging 2021; 84:124-131. [PMID: 34624400 PMCID: PMC8556357 DOI: 10.1016/j.mri.2021.09.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 09/23/2021] [Accepted: 09/30/2021] [Indexed: 10/20/2022]
Abstract
Rodent models of spinal cord injury (SCI) have been widely used in pre-clinical studies. Injuries may occur at different levels of the lumbar and thoracic cord, and the number of segments injured and their depths may vary along the spine. It is thereby challenging to build one universal RF coil that exhibits optimal performance for all spinal cord imaging applications, especially in an animal scanner with small in-bore space and limited hardware configurations. We developed an interchangeable RF coil system for a 9.4 T small animal MRI scanner, in which the users can select an optimal coil specialized for imaging specific parts of a rat spine. We also developed the associated animal management device for immobilization and positioning. The whole system allows ease of RF coil exchange, animal fixation, and positioning, and thus reduces the animal preparation time before the MRI scan significantly. Compared to a commercial general-purpose 2-cm-diameter coil that was used in our previous studies, the specialized coil optimized for Sprague-Dawley rat lumbar spinal cord imaging exhibits up to 2.4 times SNR improvement.
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Affiliation(s)
- Ming Lu
- College of Nuclear Equipment and Nuclear Engineering, Yantai University, Yantai, Shandong, China
| | - Gary Drake
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Feng Wang
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Chaoqi Mu
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
| | - Li Min Chen
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - John C Gore
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA; Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, USA; Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
| | - Xinqiang Yan
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA.
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Wang F, Zu Z, Wu TL, Yan X, Lu M, Yang PF, Byun NE, Reed JL, Gore JC, Chen LM. Sensitivity and specificity of CEST and NOE MRI in injured spinal cord in monkeys. NEUROIMAGE-CLINICAL 2021; 30:102633. [PMID: 33780866 PMCID: PMC8039857 DOI: 10.1016/j.nicl.2021.102633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 02/18/2021] [Accepted: 03/12/2021] [Indexed: 11/04/2022]
Abstract
Compare sensitivity and specificity of CEST and NOE measures from 6-pool fitting. Differentiate regional molecular signatures at and around spinal cord injury. Provide parameters that improve the diagnostic accuracy of molecular alteration. Down-sampled data acquisition can capture the characteristic molecular profile. High translational potential for clinical assessment of spinal cord injury.
Purpose The sensitivity and accuracy of chemical exchange saturation transfer (CEST) and nuclear Overhauser enhancement (NOE) effects for assessing injury-associated changes in cervical spinal cords were evaluated in squirrel monkeys. Multiple interacting pools of protons, including one identified by an NOE at −1.6 ppm relative to water (NOE(-1.6)), were derived and quantified from fitting proton Z-spectra. The effects of down-sampled data acquisitions and corrections for non-specific factors including T1, semi-solid magnetization transfer, and direct saturation of free water (DS), were investigated. The overall goal is to develop a protocol for rapid data acquisition for assessing the molecular signatures of the injured spinal cord and its surrounding regions. Methods MRI scans were recorded of anesthetized squirrel monkeys at 9.4 T, before and after a unilateral dorsal column sectioning of the cervical spinal cord. Z-spectral images at 51 different RF offsets were acquired. The amplitudes of CEST and NOE effects from multiple proton pools were quantified using a six-pool Lorenzian fitting of each Z-spectrum (MTRmfit). In addition, down-sampled data using reduced selections of RF offsets were analyzed and compared. An apparent exchange-dependent relaxation (AREXmfit) method was also used to correct for non-specific factors in quantifying regional spectra around lesion sites. Results The parametric maps from multi-pool fitting using the complete sampling data (P51e) detected unilateral changes at and around the injury. The maps derived from selected twofold down-sampled data with appropriate interpolation (P26sI51) revealed quite similar spatial distributions of different pools as those obtained using P51e at each resonance shift. Across 10 subjects, both data acquisition schemes detected significant decreases in NOE(-3.5) and NOE(-1.6) and increases in DS(0.0) and CEST(3.5) at the lesion site relative to measures of the normal tissues before injury. AREXmfit of cysts and other abnormal tissues at and around the lesion site also exhibited significant changes, especially at 3.5, −1.6 and −3.5 ppm RF offsets. Conclusion These results confirm that a reduced set of RF offsets and down sampling are adequate for CEST imaging of injured spinal cord and allow shorter imaging times and/or permit additional signal averaging. AREXmfit correction improved the accuracy of CEST and NOE measures. The results provide a rapid (~13 mins), sensitive, and accurate protocol for deriving multiple NOE and CEST effects simultaneously in spinal cord imaging at high field.
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Affiliation(s)
- Feng Wang
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, TN, USA
| | - Zhongliang Zu
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, TN, USA
| | - Tung-Lin Wu
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, USA; Department of Biomedical Engineering, Vanderbilt University, TN, USA
| | - Xinqiang Yan
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, TN, USA
| | - Ming Lu
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, TN, USA
| | - Pai-Feng Yang
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, TN, USA
| | - Nellie E Byun
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, TN, USA
| | - Jamie L Reed
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, TN, USA
| | - John C Gore
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, TN, USA; Department of Biomedical Engineering, Vanderbilt University, TN, USA
| | - Li Min Chen
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, TN, USA.
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Longitudinal changes in DTI parameters of specific spinal white matter tracts correlate with behavior following spinal cord injury in monkeys. Sci Rep 2020; 10:17316. [PMID: 33057016 PMCID: PMC7560889 DOI: 10.1038/s41598-020-74234-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 09/23/2020] [Indexed: 12/27/2022] Open
Abstract
This study aims to evaluate how parameters derived from diffusion tensor imaging reflect axonal disruption and demyelination in specific white matter tracts within the spinal cord of squirrel monkeys following traumatic injuries, and their relationships to function and behavior. After a unilateral section of the dorsal white matter tract of the cervical spinal cord, we found that both lesioned dorsal and intact lateral tracts on the lesion side exhibited prominent disruptions in fiber orientation, integrity and myelination. The degrees of pathological changes were significantly more severe in segments below the lesion than above. The lateral tract on the opposite (non-injured) side was minimally affected by the injury. Over time, RD, FA, and AD values of the dorsal and lateral tracts on the injured side closely tracked measurements of the behavioral recovery. This unilateral section of the dorsal spinal tract provides a realistic model in which axonal disruption and demyelination occur together in the cord. Our data show that specific tract and segmental FA and RD values are sensitive to the effects of injury and reflect specific behavioral changes, indicating their potential as relevant indicators of recovery or for assessing treatment outcomes. These observations have translational value for guiding future studies of human subjects with spinal cord injuries.
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Geldschläger O, Bosch D, Avdievich NI, Henning A. Ultrahigh-resolution quantitative spinal cord MRI at 9.4T. Magn Reson Med 2020; 85:1013-1027. [PMID: 32789980 DOI: 10.1002/mrm.28455] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 07/06/2020] [Accepted: 07/10/2020] [Indexed: 11/08/2022]
Abstract
PURPOSE To present the results of the first human spinal cord in vivo MRI scans at 9.4T. METHODS A human brain coil was used to image the human spinal cord at 9.4T. All anatomical images were acquired with a T2 *-weighted gradient-echo sequence. A comparison of the influence of four different B0 shimming routines on the image quality was performed. Intrinsic signal-to-noise-ratio maps were determined using a pseudo-multiple replica approach. Measurements with different echo times were compared and processed to one multiecho data image combination image. Based on the multiecho acquisitions, T2 *-relaxation time maps were calculated. Algorithmic spinal cord detection and gray matter/white matter segmentation were tested. RESULTS An echo time between 9 and 13.8 ms compromised best between gray matter/white matter contrast and image quality. A maximum in-plane resolution of 0.15 × 0.15 mm2 was achieved for anatomical images. These images offered excellent image quality and made small structures of the spinal cord visible. The scanner vendor implemented B0 shimming routine performed best during this work. Intrinsic signal-to-noise-ratio values of between 6600 and 8060 at the upper cervical spinal cord were achieved. Detection and segmentation worked reliably. An average T2 *-time of 24.88 ms ± 6.68 ms for gray matter and 19.37 ms ± 8.66 ms for white matter was calculated. CONCLUSION The proposed human brain coil can be used to image the spinal cord. The maximum in-plane resolution in this work was higher compared with the 7T results from the literature. The 9.4T acquisitions made the small structures of the spinal cord clearly visible.
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Affiliation(s)
- Ole Geldschläger
- High-Field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Dario Bosch
- High-Field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.,Biomedical Magnetic Resonance, University Hospital Tübingen, Tübingen, Germany
| | - Nikolai I Avdievich
- High-Field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Anke Henning
- High-Field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.,Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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Yang Y, Cao TT, Tian ZM, Gao H, Wen HQ, Pang M, He WJ, Wang NX, Chen YY, Wang Y, Li H, Lin JW, Kang Z, Li MM, Liu B, Rong LM. Subarachnoid transplantation of human umbilical cord mesenchymal stem cell in rodent model with subacute incomplete spinal cord injury: Preclinical safety and efficacy study. Exp Cell Res 2020; 395:112184. [PMID: 32707134 DOI: 10.1016/j.yexcr.2020.112184] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 07/13/2020] [Accepted: 07/17/2020] [Indexed: 12/22/2022]
Abstract
Functional multipotency renders human umbilical cord mesenchymal stem cell (hUC-MSC) a promising candidate for the treatment of spinal cord injury (SCI). However, its safety and efficacy have not been fully understood for clinical translation. In this study, we performed cellular, kinematic, physiological, and anatomical analyses, either in vitro or in vivo, to comprehensively evaluate the safety and efficacy associated with subarachnoid transplantation of hUC-MSCs in rats with subacute incomplete SCI. Concerning safety, hUC-MSCs were shown to have normal morphology, excellent viability, steady proliferation, typical biomarkers, stable karyotype in vitro, and no tumorigenicity both in vitro and in vivo. Following subarachnoid transplantation of hUC-MSCs in the subject rodents, the biodistribution of hUC-MSCs was restricted to the spinal cord, and no toxicity to immune system or organ function was observed. Body weight, organ weight, and the ratio of the latter upon the former between stem cell-transplanted rats and placebo-injected rats revealed no statistical differences. Regarding efficacy, hUC-MSCs could differentiate into osteoblasts, chondrocytes, adipocytes and neural progenitor cells in vitro. While in vivo studies revealed that subarachnoid transplantation of stem cells resulted in significant improvement in locomotion, earlier automatic micturition recovery and reduced lesion size, which correlated with increased regeneration of tracking fiber and reduced parenchymal inflammation. In vivo luminescence imaging showed that a few of the transplanted luciferase-labeled hUC-MSCs tended to migrate towards the lesion epicenter. Shortened latency and enhanced amplitude were also observed in both motor and sensory evoked potentials, indicating improved signal conduction in the damaged site. Immunofluorescent staining confirmed that a few of the administrated hUC-MSCs integrated into the spinal cord parenchyma and differentiated into astrocytes and oligodendrocytes, but not neurons. Moreover, decreased astrogliosis, increased remyelination, and neuron regeneration could be observed. To the best of our knowledge, this preclinical study provides detailed safety and efficacy evidence regarding intrathecal transplantation of hUC-MSCs in treating SCI for the first time and thus, supports its initiation in the following clinical trial.
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Affiliation(s)
- Yang Yang
- Department of Spine Surgery, The Third Affiliated Hospital of Sun Yat-sen University, 600 Tianhe Road, Tianhe District, Guangzhou, Guangdong Province, People's Republic of China
| | - Ting-Ting Cao
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, 1023 Shatai South Road, Baiyun District, Guangzhou, Guangdong Province, People's Republic of China
| | - Zhen-Ming Tian
- Department of Spine Surgery, The Third Affiliated Hospital of Sun Yat-sen University, 600 Tianhe Road, Tianhe District, Guangzhou, Guangdong Province, People's Republic of China
| | - Han Gao
- Department of Spine Surgery, The Third Affiliated Hospital of Sun Yat-sen University, 600 Tianhe Road, Tianhe District, Guangzhou, Guangdong Province, People's Republic of China
| | - Hui-Quan Wen
- Department of Radiology, The Third Affiliated Hospital of Sun Yat-sen University, 600 Tianhe Road, Tianhe District, Guangzhou, Guangdong Province, People's Republic of China
| | - Mao Pang
- Department of Spine Surgery, The Third Affiliated Hospital of Sun Yat-sen University, 600 Tianhe Road, Tianhe District, Guangzhou, Guangdong Province, People's Republic of China
| | - Wei-Jie He
- Department of Spine Surgery, The Third Affiliated Hospital of Sun Yat-sen University, 600 Tianhe Road, Tianhe District, Guangzhou, Guangdong Province, People's Republic of China
| | - Nan-Xiang Wang
- Department of Spine Surgery, The Third Affiliated Hospital of Sun Yat-sen University, 600 Tianhe Road, Tianhe District, Guangzhou, Guangdong Province, People's Republic of China
| | - Yu-Yong Chen
- Department of Spine Surgery, The Third Affiliated Hospital of Sun Yat-sen University, 600 Tianhe Road, Tianhe District, Guangzhou, Guangdong Province, People's Republic of China
| | - Yang Wang
- Department of Spine Surgery, The Third Affiliated Hospital of Sun Yat-sen University, 600 Tianhe Road, Tianhe District, Guangzhou, Guangdong Province, People's Republic of China
| | - He Li
- Department of Physiology, School of Basic Medical Sciences, Southern Medical University, 1023 Shatai South Road, Baiyun District, Guangzhou, Guangdong Province, People's Republic of China
| | - Jun-Wei Lin
- Department of Obstetrics, The Third Affiliated Hospital of Sun Yat-sen University, 600 Tianhe Road, Tianhe District, Guangzhou, Guangdong Province, People's Republic of China
| | - Zhuang Kang
- Department of Radiology, The Third Affiliated Hospital of Sun Yat-sen University, 600 Tianhe Road, Tianhe District, Guangzhou, Guangdong Province, People's Republic of China
| | - Mang-Mang Li
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, 1023 Shatai South Road, Baiyun District, Guangzhou, Guangdong Province, People's Republic of China.
| | - Bin Liu
- Department of Spine Surgery, The Third Affiliated Hospital of Sun Yat-sen University, 600 Tianhe Road, Tianhe District, Guangzhou, Guangdong Province, People's Republic of China.
| | - Li-Min Rong
- Department of Spine Surgery, The Third Affiliated Hospital of Sun Yat-sen University, 600 Tianhe Road, Tianhe District, Guangzhou, Guangdong Province, People's Republic of China.
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10
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Wu TL, Byun NE, Wang F, Mishra A, Janve VA, Chen LM, Gore JC. Longitudinal assessment of recovery after spinal cord injury with behavioral measures and diffusion, quantitative magnetization transfer and functional magnetic resonance imaging. NMR IN BIOMEDICINE 2020; 33:e4216. [PMID: 31943383 PMCID: PMC7155919 DOI: 10.1002/nbm.4216] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 10/08/2019] [Accepted: 10/15/2019] [Indexed: 05/09/2023]
Abstract
Spinal cord injuries (SCIs) are a leading cause of disability and can severely impact the quality of life. However, to date, the processes of spontaneous repair of damaged spinal cord remain incompletely understood, partly due to a lack of appropriate longitudinal tracking methods. Noninvasive, multiparametric magnetic resonance imaging (MRI) provides potential biomarkers for the comprehensive evaluation of spontaneous repair after SCI. In this study in rats, a clinically relevant contusion injury was introduced at the lumbar level that impairs both hindlimb motor and sensory functions. Quantitative MRI measurements were acquired at baseline and serially post-SCI for up to 2 wk. The progressions of injury and spontaneous recovery in both white and gray matter were tracked longitudinally using pool-size ratio (PSR) measurements derived from quantitative magnetization transfer (qMT) methods, measurements of water diffusion parameters using diffusion tensor imaging (DTI) and intrasegment functional connectivity derived from resting state functional MRI. Changes in these quantitative imaging measurements were correlated with behavioral readouts. We found (a) a progressive decrease in PSR values within 2 wk post-SCI, indicating a progressive demyelination at the center of the injury that was validated with histological staining, (b) PSR correlated closely with fractional anisotropy and transverse relaxation of free water, but did not show significant correlations with behavioral recovery, and (c) preliminary evidence that SCI induced a decrease in functional connectivity between dorsal horns below the injury site at 24 h. Findings from this study not only confirm the value of qMT and DTI methods for assessing the myelination state of injured spinal cord but indicate that they may also have further implications on whether therapies targeted towards remyelination may be appropriate. Additionally, a better understanding of changes after SCI provides valuable information to guide and assess interventions.
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Affiliation(s)
- Tung-Lin Wu
- Vanderbilt University Institute of Imaging Science, Nashville, TN, 37232, United States
- Biomedical Engineering, Vanderbilt University, Nashville, TN, 37232, United States
| | - Nellie E. Byun
- Vanderbilt University Institute of Imaging Science, Nashville, TN, 37232, United States
- Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, 37232, United States
| | - Feng Wang
- Vanderbilt University Institute of Imaging Science, Nashville, TN, 37232, United States
- Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, 37232, United States
| | - Arabinda Mishra
- Vanderbilt University Institute of Imaging Science, Nashville, TN, 37232, United States
- Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, 37232, United States
| | - Vaibhav A. Janve
- Vanderbilt University Institute of Imaging Science, Nashville, TN, 37232, United States
- Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, 37232, United States
| | - Li Min Chen
- Vanderbilt University Institute of Imaging Science, Nashville, TN, 37232, United States
- Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, 37232, United States
| | - John C. Gore
- Vanderbilt University Institute of Imaging Science, Nashville, TN, 37232, United States
- Biomedical Engineering, Vanderbilt University, Nashville, TN, 37232, United States
- Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, 37232, United States
- Physics and Astronomy, Vanderbilt University, Nashville, TN, 37232, United States
- Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, United States
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11
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Optimization of a transmit/receive surface coil for squirrel monkey spinal cord imaging. Magn Reson Imaging 2020; 68:197-202. [PMID: 32087231 DOI: 10.1016/j.mri.2020.02.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Revised: 02/14/2020] [Accepted: 02/15/2020] [Indexed: 12/20/2022]
Abstract
MR Imaging the spinal cord of non-human primates (NHP), such as squirrel monkey, is important since the injuries in NHP resemble those that afflict human spinal cords. Our previous studies have reported a multi-parametric MRI protocol, including functional MRI, diffusion tensor imaging, quantitative magnetization transfer and chemical exchange saturation transfer, which allows non-invasive detection and monitoring of injury-associated structural, functional and molecular changes over time. High signal-to-noise ratio (SNR) is critical for obtaining high-resolution images and robust estimates of MRI parameters. In this work, we describe our construction and use of a single channel coil designed to maximize the SNR for imaging the squirrel monkey cervical spinal cord in a 21 cm bore magnet at 9.4 T. We first numerically optimized the coil dimension of a single loop coil and then evaluated the benefits of a quadrature design. We then built an optimized coil based on the simulation results and compared its SNR performance with a non-optimized single coil in both phantoms and in vivo.
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12
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Spatiotemporal trajectories of quantitative magnetization transfer measurements in injured spinal cord using simplified acquisitions. NEUROIMAGE-CLINICAL 2019; 23:101921. [PMID: 31491830 PMCID: PMC6639592 DOI: 10.1016/j.nicl.2019.101921] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 06/04/2019] [Accepted: 06/30/2019] [Indexed: 12/19/2022]
Abstract
Purpose This study aims to systematically evaluate the accuracy and precision of pool size ratio (PSR) measurements from quantitative magnetization transfer (qMT) acquisitions using simplified models in the context of assessing injury-associated spatiotemporal changes in spinal cords of non-human primates. This study also aims to characterize changes in the spinal tissue pathology in individual subjects, both regionally and longitudinally, in order to demonstrate the relationship between regional tissue compositional changes and sensorimotor behavioral recovery after cervical spinal cord injury (SCI). Methods MRI scans were recorded on anesthetized monkeys at 9.4 T, before and serially after a unilateral section of the dorsal column tract. Images were acquired following saturating RF pulses at different offset frequencies. Models incorporating two pools of protons but with differing numbers of variable parameters were used to fit the data to derive qMT parameters. The results using different amounts of measured data and assuming different numbers of variable model parameters were compared. Behavioral impairments and recovery were assessed by a food grasping-retrieving task. Histological sections were obtained post mortem for validation of the injury. Results QMT fitting provided maps of pool size ratio (PSR), the relative amounts of immobilized protons exchanging magnetization compared to the “free” water. All the selected modeling approaches detected a lesion/cyst at the site of injury as significant reductions in PSR values. The regional contrasts in the PSR maps obtained using the different fittings varied, but the 2-parameter fitting results showed strong positive correlations with results from 5-parameter modeling. 2-parameter fitting results with modest (>3) RF offsets showed comparable sensitivity for detecting demyelination in white matter and loss of macromolecules in gray matter around lesion sites compared to 5-parameter fitting with fully-sampled data acquisitions. Histology confirmed that decreases of PSR corresponded to regional demyelination around lesion sites, especially when demyelination occurred along the dorsal column on the injury side. Longitudinally, PSR values of injured dorsal column tract and gray matter horns exhibited remarkable recovery that associated with behavioral improvement. Conclusion Simplified qMT modeling approaches provide efficient and sensitive means to detect and characterize injury-associated demyelination in white matter tracts and loss of macromolecules in gray matter and to monitor its recovery over time. Simplified 2-parameter and fully sampled 5-parameter qMT modeling achieved comparable accuracy and precision of PSR values. Successfully tracked and differentiated myelination states of specific WM tracts and macromolecular changes in GM horns. Recovery of WM and GM pathology assessed by qMT correlated with improvements in hand uses after injury. High translational potential for clinical studies of human patients with spinal cord injury.
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13
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Zu Z. Toward more reliable measurements of NOE effects in CEST spectra at around -1.6 ppm (NOE (-1.6)) in rat brain. Magn Reson Med 2019; 81:208-219. [PMID: 30058128 PMCID: PMC6258343 DOI: 10.1002/mrm.27370] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 04/24/2018] [Accepted: 04/29/2018] [Indexed: 01/17/2023]
Abstract
PURPOSE Recently, a new relayed nuclear Overhauser enhancement (NOE) saturation transfer effect at around -1.6 parts per million, termed NOE(-1.6), and its potential applications in tumor and stroke were reported by several institutes. However, there is a concern of the reproducibility of NOE(-1.6) measurements because it is not reported by many other publications. This paper aims to study the influence of typically overlooked experimental settings on the NOE(-1.6) signal and to build a framework for more reliable measurements of NOE(-1.6) at 9.4T. METHODS Z-spectra were obtained in rat brains. A fitting approach was performed to quantify all known saturation transfer effects except NOE(-1.6). Residual signals were obtained by removing these confounding effects from Z-spectra and were then used to quantify NOE(-1.6). Multislice imaging was performed to study the NOE(-1.6) dependence on brain regions. The influences of euthanasia, anesthesia, breathing gases, and RF irradiation power were also evaluated. RESULTS Results demonstrate that the NOE(-1.6) signal contributions are often not clearly observable in raw Z-spectra at relatively high irradiation powers due to, for example, the direct water saturation effect, but they can be visualized after removing other nonspecific effects. In addition, the NOE(-1.6) effect depends on brain region, decreases postmortem, shifts after long-duration anesthesia, and may be enhanced by increasing O2 and N2 O breathing air concentrations. CONCLUSION Because the NOE(-1.6) effect is more susceptible to the direct water saturation effect and more sensitive to physiological conditions than are other CEST effects, incorporating known sensitivities into the experimental design and data analysis is necessary to ensure more reliable NOE(-1.6) results.
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Affiliation(s)
- Zhongliang Zu
- Vanderbilt University Institute of Imaging Science, Nashville, Tennessee, USA
- Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
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14
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Wang F, Katagiri D, Li K, Takahashi K, Wang S, Nagasaka S, Li H, Quarles CC, Zhang MZ, Shimizu A, Gore JC, Harris RC, Takahashi T. Assessment of renal fibrosis in murine diabetic nephropathy using quantitative magnetization transfer MRI. Magn Reson Med 2018; 80:2655-2669. [PMID: 29845659 PMCID: PMC6269231 DOI: 10.1002/mrm.27231] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Revised: 03/19/2018] [Accepted: 04/03/2018] [Indexed: 12/26/2022]
Abstract
PURPOSE Renal fibrosis is a hallmark of progressive renal disease; however, current clinical tests are insufficient for assessing renal fibrosis. Here we evaluated the utility of quantitative magnetization transfer MRI in detecting renal fibrosis in a murine model of progressive diabetic nephropathy (DN). METHODS The db/db eNOS-/- mice, a well-recognized model of progressive DN, and normal wild-type mice were imaged at 7T. The quantitative magnetization transfer data were collected in coronal plane using a 2D magnetization transfer prepared spoiled gradient echo sequence with a Gaussian-shaped presaturation pulse. Parameters were derived using a two-pool fitting model. A normal range of cortical pool size ratio (PSR) was defined as Mean±2SD of wild-type kidneys (N = 20). The cortical regions whose PSR values exceeded this threshold (threshold PSR) were assessed. The correlations between the PSR-based and histological (collagen IV or picrosirius red stain) fibrosis measurements were evaluated. RESULTS Compared with wild-type mice, moderate increases in mean PSR values and scattered clusters of high PSR region were observed in cortex of DN mouse kidneys. Abnormally high PSR regions (% area) that were detected by the threshold PSR were significantly increased in renal cortexes of DN mice. These regions progressively increased on aging and highly correlated with histological fibrosis measures, while the mean PSR values correlated much less. CONCLUSION Renal fibrosis in DN can be assessed by the quantitative magnetization transfer MRI and threshold analysis. This technique may be used as a novel imaging biomarker for DN and other renal diseases.
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Affiliation(s)
- Feng Wang
- Vanderbilt University Institute of Imaging Science, TN, USA
- Department of Radiology and Radiological Sciences, Vanderbilt University School of Medicine, TN, USA
| | - Daisuke Katagiri
- Division of Nephrology and Hypertension, Vanderbilt University School of Medicine, TN, USA
| | - Ke Li
- Vanderbilt University Institute of Imaging Science, TN, USA
| | - Keiko Takahashi
- Division of Nephrology and Hypertension, Vanderbilt University School of Medicine, TN, USA
| | - Suwan Wang
- Division of Nephrology and Hypertension, Vanderbilt University School of Medicine, TN, USA
| | - Shinya Nagasaka
- Division of Nephrology and Hypertension, Vanderbilt University School of Medicine, TN, USA
- Department of Analytic Human Pathology, Nippon Medical School, Tokyo, Japan
| | - Hua Li
- Vanderbilt University Institute of Imaging Science, TN, USA
- Department of Radiology and Radiological Sciences, Vanderbilt University School of Medicine, TN, USA
| | - C. Chad Quarles
- Vanderbilt University Institute of Imaging Science, TN, USA
- Department of Radiology and Radiological Sciences, Vanderbilt University School of Medicine, TN, USA
| | - Ming-Zhi Zhang
- Division of Nephrology and Hypertension, Vanderbilt University School of Medicine, TN, USA
| | - Akira Shimizu
- Department of Analytic Human Pathology, Nippon Medical School, Tokyo, Japan
| | - John C. Gore
- Vanderbilt University Institute of Imaging Science, TN, USA
- Department of Radiology and Radiological Sciences, Vanderbilt University School of Medicine, TN, USA
| | - Raymond C. Harris
- Division of Nephrology and Hypertension, Vanderbilt University School of Medicine, TN, USA
| | - Takamune Takahashi
- Division of Nephrology and Hypertension, Vanderbilt University School of Medicine, TN, USA
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15
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Baklaushev VP, Durov OV, Kim SV, Gulaev EV, Gubskiy IL, Konoplyannikov MA, Zabozlaev FG, Zhang C, Agrba VZ, Orlov SV, Lapin BA, Troitskiy AV, Averyanov AV, Ahlfors JE. Development of a motor and somatosensory evoked potentials-guided spinal cord Injury model in non-human primates. J Neurosci Methods 2018; 311:200-214. [PMID: 30393204 DOI: 10.1016/j.jneumeth.2018.10.030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Accepted: 10/22/2018] [Indexed: 02/07/2023]
Abstract
Background Nonhuman primates (NHP) may provide the most adequate (in terms of neuroanatomy and neurophysiology) model of spinal cord injury (SCI) for testing regenerative therapies, but bioethical considerations exclude their use in severe SCI. New Method A reproducible model of SCI at the lower thoracic level has been developed in Rhesus macaques. The model comprises surgical resection of 25% of the spinal cord in the projection of the dorsal funiculus and dorsolateral corticospinal pathways, controlled via registration of intraoperative evoked potentials (EPs). The animals were evaluated using the modified Hindlimb score, MRI, SSEP, and MEP over a time period of 8-12 weeks post-SCI, followed by histological examination. Results Complete disappearance of intraoperative EPs from distal hindlimb muscles without restoration within two weeks post-SCI was an indicator for irreversible disruption of the abovementioned pathways. As a result, controlled damage to the spinal cord was achieved in three NHPs, clinically manifested as irreversible lower monoplegia. No significant functional restoration was observed in these NHPs up to 12 weeks post-SCI. Demyelination of the damaged ascending tracts was detected. Disturbances in pelvic organ function were not observed in all animals. Comparison with existing methods The new method of EPs-guided SCI allows a more controlled and irreversible damage to the spinal cord compared with contusion and other transection approaches. Conclusions This method to induce complete SCI in NHP is well tolerated, reproducible and ethically acceptable: these are valuable attributes in a preclinical model that will hopefully help advance testing of new regenerative therapies in SCI.
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Affiliation(s)
- V P Baklaushev
- Federal Research and Clinical Center of Specialized Medical Care and Medical Technologies, FMBA, 28 Orekhovy Blvd., 115682 Moscow, Russia; Institute for Advanced Training, FMBA, Moscow, Russia.
| | - O V Durov
- Federal Research and Clinical Center of Specialized Medical Care and Medical Technologies, FMBA, 28 Orekhovy Blvd., 115682 Moscow, Russia
| | - S V Kim
- Federal Research and Clinical Center of Specialized Medical Care and Medical Technologies, FMBA, 28 Orekhovy Blvd., 115682 Moscow, Russia
| | - E V Gulaev
- Federal Research and Clinical Center of Specialized Medical Care and Medical Technologies, FMBA, 28 Orekhovy Blvd., 115682 Moscow, Russia
| | - I L Gubskiy
- Research and Education Center for Medicinal Nanobiotechnology, Pirogov Russian National Research Medical University, Moscow, Russia
| | - M A Konoplyannikov
- Federal Research and Clinical Center of Specialized Medical Care and Medical Technologies, FMBA, 28 Orekhovy Blvd., 115682 Moscow, Russia; Institute of Regenerative Medicine, Sechenov Medical University, Moscow, Russia
| | - F G Zabozlaev
- Federal Research and Clinical Center of Specialized Medical Care and Medical Technologies, FMBA, 28 Orekhovy Blvd., 115682 Moscow, Russia
| | - C Zhang
- Research and Education Center for Medicinal Nanobiotechnology, Pirogov Russian National Research Medical University, Moscow, Russia; Department of Bone and Soft Tissue Tumors, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, China
| | - V Z Agrba
- Institute of Medicinal Primatology Russian Academy of Science, Sochi, Russia
| | - S V Orlov
- Institute of Medicinal Primatology Russian Academy of Science, Sochi, Russia
| | - B A Lapin
- Institute of Medicinal Primatology Russian Academy of Science, Sochi, Russia
| | - A V Troitskiy
- Federal Research and Clinical Center of Specialized Medical Care and Medical Technologies, FMBA, 28 Orekhovy Blvd., 115682 Moscow, Russia; Institute for Advanced Training, FMBA, Moscow, Russia
| | - A V Averyanov
- Federal Research and Clinical Center of Specialized Medical Care and Medical Technologies, FMBA, 28 Orekhovy Blvd., 115682 Moscow, Russia
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16
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Liu CB, Yang DG, Zhang X, Zhang WH, Li DP, Zhang C, Qin C, Du LJ, Li J, Gao F, Zhang J, Zuo ZT, Yang ML, Li JJ. Degeneration of white matter and gray matter revealed by diffusion tensor imaging and pathological mechanism after spinal cord injury in canine. CNS Neurosci Ther 2018; 25:261-272. [PMID: 30076687 DOI: 10.1111/cns.13044] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 07/07/2018] [Accepted: 07/11/2018] [Indexed: 12/13/2022] Open
Abstract
AIM Exploration of the mechanism of spinal cord degeneration may be the key to treatment of spinal cord injury (SCI). This study aimed to investigate the degeneration of white matter and gray matter and pathological mechanism in canine after SCI. METHODS Diffusion tensor imaging (DTI) was performed on canine models with normal (n = 5) and injured (n = 7) spinal cords using a 3.0T MRI scanner at precontusion and 3 hours, 24 hours, 6 weeks, and 12 weeks postcontusion. The tissue sections were stained using H&E and immunohistochemistry. RESULTS For white matter, fractional anisotropy (FA) values significantly decreased in lesion epicenter, caudal segment 1 cm away from epicenter, and caudal segment 2 cm away from epicenter (P = 0.003, P = 0.004, and P = 0.013, respectively) after SCI. Apparent diffusion coefficient (ADC) values were initially decreased and then increased in lesion epicenter and caudal segment 1 cm away from epicenter (P < 0.001 and P = 0.010, respectively). There are no significant changes in FA and ADC values in rostral segments (P > 0.05). For gray matter, ADC values decreased initially and then increased in lesion epicenter (P < 0.001), and overall trend decreased in caudal segment 1 cm away from epicenter (P = 0.039). FA values did not change significantly (P > 0.05). Pathological examination confirmed the dynamic changes of DTI parameters. CONCLUSION Diffusion tensor imaging is more sensitive to degeneration of white matter than gray matter, and the white matter degeneration may be not symmetrical which meant the caudal degradation appeared to be more severe than the rostral one.
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Affiliation(s)
- Chang-Bin Liu
- School of Rehabilitation Medicine, Capital Medical University, Beijing, China.,Department of Spinal and Neural Function Reconstruction, China Rehabilitation Research Center, Beijing, China.,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China.,China Rehabilitation Science Institute, Beijing, China.,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - De-Gang Yang
- School of Rehabilitation Medicine, Capital Medical University, Beijing, China.,Department of Spinal and Neural Function Reconstruction, China Rehabilitation Research Center, Beijing, China.,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China.,China Rehabilitation Science Institute, Beijing, China.,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Xin Zhang
- School of Rehabilitation Medicine, Capital Medical University, Beijing, China.,Department of Spinal and Neural Function Reconstruction, China Rehabilitation Research Center, Beijing, China.,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China.,China Rehabilitation Science Institute, Beijing, China.,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Wen-Hao Zhang
- School of Rehabilitation Medicine, Capital Medical University, Beijing, China.,Department of Spinal and Neural Function Reconstruction, China Rehabilitation Research Center, Beijing, China.,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China.,China Rehabilitation Science Institute, Beijing, China.,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Da-Peng Li
- School of Rehabilitation Medicine, Capital Medical University, Beijing, China.,Department of Spinal and Neural Function Reconstruction, China Rehabilitation Research Center, Beijing, China.,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China.,China Rehabilitation Science Institute, Beijing, China.,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Chao Zhang
- School of Rehabilitation Medicine, Capital Medical University, Beijing, China.,Department of Spinal and Neural Function Reconstruction, China Rehabilitation Research Center, Beijing, China.,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China.,China Rehabilitation Science Institute, Beijing, China.,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Chuan Qin
- School of Rehabilitation Medicine, Capital Medical University, Beijing, China.,Department of Spinal and Neural Function Reconstruction, China Rehabilitation Research Center, Beijing, China.,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China.,China Rehabilitation Science Institute, Beijing, China.,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Liang-Jie Du
- School of Rehabilitation Medicine, Capital Medical University, Beijing, China.,Department of Spinal and Neural Function Reconstruction, China Rehabilitation Research Center, Beijing, China.,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China.,China Rehabilitation Science Institute, Beijing, China.,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Jun Li
- School of Rehabilitation Medicine, Capital Medical University, Beijing, China.,Department of Spinal and Neural Function Reconstruction, China Rehabilitation Research Center, Beijing, China.,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China.,China Rehabilitation Science Institute, Beijing, China.,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Feng Gao
- School of Rehabilitation Medicine, Capital Medical University, Beijing, China.,Department of Spinal and Neural Function Reconstruction, China Rehabilitation Research Center, Beijing, China.,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China.,China Rehabilitation Science Institute, Beijing, China.,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Jie Zhang
- School of Rehabilitation Medicine, Capital Medical University, Beijing, China.,Department of Spinal and Neural Function Reconstruction, China Rehabilitation Research Center, Beijing, China.,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China.,China Rehabilitation Science Institute, Beijing, China.,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Zhen-Tao Zuo
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,The Innovation Center of Excellence on Brain Science, Chinese Academy of Sciences, Beijing, China.,Sino-Danish College, University of Chinese Academy of Sciences, Beijing, China
| | - Ming-Liang Yang
- School of Rehabilitation Medicine, Capital Medical University, Beijing, China.,Department of Spinal and Neural Function Reconstruction, China Rehabilitation Research Center, Beijing, China.,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China.,China Rehabilitation Science Institute, Beijing, China.,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Jian-Jun Li
- School of Rehabilitation Medicine, Capital Medical University, Beijing, China.,Department of Spinal and Neural Function Reconstruction, China Rehabilitation Research Center, Beijing, China.,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China.,China Rehabilitation Science Institute, Beijing, China.,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
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17
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Zu Z, Afzal A, Li H, Xie J, Gore JC. Spin-lock imaging of early tissue pH changes in ischemic rat brain. NMR IN BIOMEDICINE 2018; 31:e3893. [PMID: 29424463 PMCID: PMC5854549 DOI: 10.1002/nbm.3893] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 11/23/2017] [Accepted: 12/07/2017] [Indexed: 05/03/2023]
Abstract
We have previously reported that the dispersion of spin-lattice relaxation rates in the rotating frame (R1ρ ) of tissue water protons at high field can be dominated by chemical exchange contributions. Ischemia in brain causes changes in tissue pH, which in turn may affect proton exchange rates. Amide proton transfer (APT, a form of chemical exchange saturation transfer) has been shown to be sensitive to chemical exchange rates and able to detect pH changes non-invasively following ischemic stroke. However, the specificity of APT to pH changes is decreased because of the influence of several other factors that affect magnetization transfer. R1ρ is less influenced by such confounding factors and thus may be more specific for detecting variations in pH. Here, we applied a spin-locking sequence to detect ischemic stroke in animal models. Although R1ρ images acquired with a single spin-locking amplitude (ω1 ) have previously been used to assess stroke, here we use ΔR1ρ , which is the difference in R1ρ values acquired with two different locking fields to emphasize selectively the contribution of chemical exchange effects. Numerical simulations with different exchange rates and measurements of tissue homogenates with different pH were performed to evaluate the specificity of ΔR1ρ to detect tissue acidosis. Spin-lock and APT data were acquired on five rat brains after ischemic strokes induced via middle cerebral artery occlusions. Correlations between these data were analyzed at different time points after the onset of stroke. The results show that ΔR1ρ (but not R1ρ acquired with a single ω1 ) was significantly correlated with APT metrics consistent with ΔR1ρ varying with pH.
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Affiliation(s)
- Zhongliang Zu
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA
- Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Aqeela Afzal
- Department of Neurological Surgery, Vanderbilt University, Nashville, Tennessee, USA
| | - Hua Li
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA
- Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Jingping Xie
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA
- Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - John C. Gore
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA
- Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
- Deparment of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee, USA
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
- Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
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18
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Barry RL, Vannesjo SJ, By S, Gore JC, Smith SA. Spinal cord MRI at 7T. Neuroimage 2018; 168:437-451. [PMID: 28684332 PMCID: PMC5894871 DOI: 10.1016/j.neuroimage.2017.07.003] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2016] [Revised: 06/30/2017] [Accepted: 07/02/2017] [Indexed: 11/25/2022] Open
Abstract
Magnetic resonance imaging (MRI) of the human spinal cord at 7T has been demonstrated by a handful of research sites worldwide, and the spinal cord remains one of the areas in which higher fields and resolution could have high impact. The small diameter of the cord (∼1 cm) necessitates high spatial resolution to minimize partial volume effects between gray and white matter, and so MRI of the cord can greatly benefit from increased signal-to-noise ratio and contrasts at ultra-high field (UHF). Herein we review the current state of UHF spinal cord imaging. Technical challenges to successful UHF spinal cord MRI include radiofrequency (B1) nonuniformities and a general lack of optimized radiofrequency coils, amplified physiological noise, and an absence of methods for robust B0 shimming along the cord to mitigate image distortions and signal losses. Numerous solutions to address these challenges have been and are continuing to be explored, and include novel approaches for signal excitation and acquisition, dynamic shimming and specialized shim coils, and acquisitions with increased coverage or optimal slice angulations.
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Affiliation(s)
- Robert L Barry
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA; Department of Radiology, Harvard Medical School, Boston, MA, USA.
| | - S Johanna Vannesjo
- Oxford Centre for Functional MRI of the Brain (FMRIB), Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Samantha By
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
| | - John C Gore
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Seth A Smith
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
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19
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Liu C, Yang D, Li J, Li D, Yang M, Sun W, Meng Q, Zhang W, Cai C, Du L, Li J, Gao F, Gu R, Feng Y, Dong X, Miao Q, Yang X, Zuo Z. Dynamic diffusion tensor imaging of spinal cord contusion: A canine model. J Neurosci Res 2018; 96:1093-1103. [PMID: 29485189 DOI: 10.1002/jnr.24222] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 12/29/2017] [Accepted: 01/12/2018] [Indexed: 11/08/2022]
Abstract
This study aimed to explore the dynamic diffusion tensor imaging (DTI) of changes in spinal cord contusion using a canine model of injury involving rostral and caudal levels. In this study, a spinal cord contusion model was established in female dogs using a custom-made weight-drop lesion device. DTI was performed on dogs with injured spinal cords (n=7) using a Siemens 3.0T MRI scanner at pre-contusion and at 3 h, 24 h, 6 weeks and 12 weeks post-injury. The tissue sections were stained for immunohistochemical analysis. Canine models of spinal cord contusion were created successfully using the weight-drop lesion device. The fractional anisotropy (FA) value of lesion epicenter decreased, while the apparent diffusion coefficient (ADC), mean diffusivity (MD), and radial diffusivity (RD) values increased, and the extent of the curve was apparent gradually. The site and time affected the DTI parameters significantly in the whole spinal cord, ADC (site, P < 0.001 and time, P = 0.077, respectively); FA (site, P < 0.001 and time, P = 0.002, respectively). Immunohistological analysis of GFAP and NF revealed the pathologic changes of reactive astrocytes and axons, as well as the cavity and glial scars occurring during chronic SCI. DTI is a sensitive and noninvasive imaging tool useful to assess edema, hemorrhage, cavity formation, structural damage and reconstruction of axon, and myelin in dogs. The DTI parameters after contusion vary. However, the curves of ADC, MD, and RD were nearly similar and the FA curve was distinct. All the DTI parameters were affected by distance and time.
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Affiliation(s)
- Changbin Liu
- School of Rehabilitation Medicine, Capital Medical University, Beijing, 100068, China.,Department of Spinal and Neural Function Reconstruction, China Rehabilitation Research Center, Beijing, 100068, China.,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, 100068, China.,China Rehabilitation Science Institute, Beijing, 100068, China.,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, 100068, China
| | - Degang Yang
- School of Rehabilitation Medicine, Capital Medical University, Beijing, 100068, China.,Department of Spinal and Neural Function Reconstruction, China Rehabilitation Research Center, Beijing, 100068, China.,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, 100068, China.,China Rehabilitation Science Institute, Beijing, 100068, China.,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, 100068, China
| | - Jianjun Li
- School of Rehabilitation Medicine, Capital Medical University, Beijing, 100068, China.,Department of Spinal and Neural Function Reconstruction, China Rehabilitation Research Center, Beijing, 100068, China.,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, 100068, China.,China Rehabilitation Science Institute, Beijing, 100068, China.,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, 100068, China
| | - Dapeng Li
- School of Rehabilitation Medicine, Capital Medical University, Beijing, 100068, China.,Department of Spinal and Neural Function Reconstruction, China Rehabilitation Research Center, Beijing, 100068, China.,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, 100068, China.,China Rehabilitation Science Institute, Beijing, 100068, China.,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, 100068, China
| | - Mingliang Yang
- School of Rehabilitation Medicine, Capital Medical University, Beijing, 100068, China.,Department of Spinal and Neural Function Reconstruction, China Rehabilitation Research Center, Beijing, 100068, China.,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, 100068, China.,China Rehabilitation Science Institute, Beijing, 100068, China.,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, 100068, China
| | - Wei Sun
- School of Rehabilitation Medicine, Capital Medical University, Beijing, 100068, China.,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, 100068, China.,China Rehabilitation Science Institute, Beijing, 100068, China.,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, 100068, China
| | - Qianru Meng
- School of Rehabilitation Medicine, Capital Medical University, Beijing, 100068, China.,Department of Spinal and Neural Function Reconstruction, China Rehabilitation Research Center, Beijing, 100068, China.,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, 100068, China.,China Rehabilitation Science Institute, Beijing, 100068, China.,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, 100068, China
| | - Wenhao Zhang
- School of Rehabilitation Medicine, Capital Medical University, Beijing, 100068, China.,Department of Spinal and Neural Function Reconstruction, China Rehabilitation Research Center, Beijing, 100068, China.,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, 100068, China.,China Rehabilitation Science Institute, Beijing, 100068, China.,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, 100068, China
| | - Chang Cai
- School of Rehabilitation Medicine, Capital Medical University, Beijing, 100068, China.,Department of Spinal and Neural Function Reconstruction, China Rehabilitation Research Center, Beijing, 100068, China.,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, 100068, China.,China Rehabilitation Science Institute, Beijing, 100068, China.,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, 100068, China
| | - Liangjie Du
- School of Rehabilitation Medicine, Capital Medical University, Beijing, 100068, China.,Department of Spinal and Neural Function Reconstruction, China Rehabilitation Research Center, Beijing, 100068, China.,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, 100068, China.,China Rehabilitation Science Institute, Beijing, 100068, China.,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, 100068, China
| | - Jun Li
- School of Rehabilitation Medicine, Capital Medical University, Beijing, 100068, China.,Department of Spinal and Neural Function Reconstruction, China Rehabilitation Research Center, Beijing, 100068, China.,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, 100068, China.,China Rehabilitation Science Institute, Beijing, 100068, China.,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, 100068, China
| | - Feng Gao
- School of Rehabilitation Medicine, Capital Medical University, Beijing, 100068, China.,Department of Spinal and Neural Function Reconstruction, China Rehabilitation Research Center, Beijing, 100068, China.,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, 100068, China.,China Rehabilitation Science Institute, Beijing, 100068, China.,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, 100068, China
| | - Rui Gu
- School of Rehabilitation Medicine, Capital Medical University, Beijing, 100068, China.,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, 100068, China.,China Rehabilitation Science Institute, Beijing, 100068, China.,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, 100068, China
| | - Yutong Feng
- School of Rehabilitation Medicine, Capital Medical University, Beijing, 100068, China.,Department of Spinal and Neural Function Reconstruction, China Rehabilitation Research Center, Beijing, 100068, China.,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, 100068, China.,China Rehabilitation Science Institute, Beijing, 100068, China.,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, 100068, China
| | - Xuechao Dong
- School of Rehabilitation Medicine, Capital Medical University, Beijing, 100068, China.,Department of Spinal and Neural Function Reconstruction, China Rehabilitation Research Center, Beijing, 100068, China.,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, 100068, China.,China Rehabilitation Science Institute, Beijing, 100068, China.,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, 100068, China
| | - Qi Miao
- Zibo Shanhang Medical Engineering Co., ltd, Zibo, Shandong, 255000, China
| | - Xinghua Yang
- School of Public Health, Capital Medical University, 10 Xitoutiao, Youanmen, Beijing, 100069, China
| | - Zhentao Zuo
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,The Innovation Center of Excellence on Brain Science, Chinese Academy of Sciences, Beijing, 100049, China.,Sino-Danish College, University of Chinese Academy of Sciences, Beijing, 100049, China
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20
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Zhang XY, Wang F, Xu J, Gochberg DF, Gore JC, Zu Z. Increased CEST specificity for amide and fast-exchanging amine protons using exchange-dependent relaxation rate. NMR IN BIOMEDICINE 2018; 31:10.1002/nbm.3863. [PMID: 29193448 PMCID: PMC5773365 DOI: 10.1002/nbm.3863] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 10/22/2017] [Accepted: 10/25/2017] [Indexed: 05/10/2023]
Abstract
Chemical exchange saturation transfer (CEST) imaging of amides at 3.5 ppm and fast-exchanging amines at 3 ppm provides a unique means to enhance the sensitivity of detection of, for example, proteins/peptides and neurotransmitters, respectively, and hence can provide important information on molecular composition. However, despite the high sensitivity relative to conventional magnetic resonance spectroscopy (MRS), in practice, CEST often has relatively poor specificity. For example, CEST signals are typically influenced by several confounding effects, including direct water saturation (DS), semi-solid non-specific magnetization transfer (MT), the influence of water relaxation times (T1w ) and nearby overlapping CEST signals. Although several editing techniques have been developed to increase the specificity by removing DS, semi-solid MT and T1w influences, it is still challenging to remove overlapping CEST signals from different exchanging sites. For instance, the amide proton transfer (APT) signal could be contaminated by CEST effects from fast-exchanging amines at 3 ppm and intermediate-exchanging amines at 2 ppm. The current work applies an exchange-dependent relaxation rate (Rex ) to address this problem. Simulations demonstrate that: (1) slowly exchanging amides and fast-exchanging amines have distinct dependences on irradiation powers; and (2) Rex serves as a resonance frequency high-pass filter to selectively reduce CEST signals with resonance frequencies closer to water. These characteristics of Rex provide a means to isolate the APT signal from amines. In addition, previous studies have shown that CEST signals from fast-exchanging amines have no distinct features around their resonance frequencies. However, Rex gives Lorentzian lineshapes centered at their resonance frequencies for fast-exchanging amines and thus can significantly increase the specificity of CEST imaging for amides and fast-exchanging amines.
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Affiliation(s)
- Xiao-Yong Zhang
- Vanderbilt University Institute of Imaging Science
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center
| | - Feng Wang
- Vanderbilt University Institute of Imaging Science
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center
| | - Junzhong Xu
- Vanderbilt University Institute of Imaging Science
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center
- Department of Physics and Astronomy, Vanderbilt University
- Department of Biomedical Engineering, Vanderbilt University
| | - Daniel F. Gochberg
- Vanderbilt University Institute of Imaging Science
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center
- Department of Physics and Astronomy, Vanderbilt University
| | - John C. Gore
- Vanderbilt University Institute of Imaging Science
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center
- Department of Physics and Astronomy, Vanderbilt University
- Department of Biomedical Engineering, Vanderbilt University
- Department of Molecular Physiology and Biophysics
| | - Zhongliang Zu
- Vanderbilt University Institute of Imaging Science
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center
- Correspondence to: Zhongliang Zu, Ph.D., Vanderbilt University Institute of Imaging Science, 1161 21st Ave. S, Medical Center North, AAA-3112, Nashville, TN 37232-2310, , Phone: 615-875-9815, Fax: 615-322-0734
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21
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Wang F, Takahashi K, Li H, Zu Z, Li K, Xu J, Harris RC, Takahashi T, Gore JC. Assessment of unilateral ureter obstruction with multi-parametric MRI. Magn Reson Med 2017; 79:2216-2227. [PMID: 28736875 DOI: 10.1002/mrm.26849] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 06/29/2017] [Accepted: 07/03/2017] [Indexed: 12/13/2022]
Abstract
PURPOSE Quantitative multi-parametric MRI (mpMRI) methods may allow the assessment of renal injury and function in a sensitive and objective manner. This study aimed to evaluate an array of MRI methods that exploit endogenous contrasts including relaxation rates, pool size ratio (PSR) derived from quantitative magnetization transfer (qMT), chemical exchange saturation transfer (CEST), nuclear Overhauser enhancement (NOE), and apparent diffusion coefficient (ADC) for their sensitivity and specificity in detecting abnormal features associated with kidney disease in a murine model of unilateral ureter obstruction (UUO). METHODS MRI scans were performed in anesthetized C57BL/6N mice 1, 3, or 6 days after UUO at 7T. Paraffin tissue sections were stained with Masson trichrome following MRI. RESULTS Compared to contralateral kidneys, the cortices of UUO kidneys showed decreases of relaxation rates R1 and R2 , PSR, NOE, and ADC. No significant changes in CEST effects were observed for the cortical region of UUO kidneys. The MRI parametric changes in renal cortex are related to tubular cell death, tubular atrophy, tubular dilation, urine retention, and interstitial fibrosis in the cortex of UUO kidneys. CONCLUSION Measurements of multiple MRI parameters provide comprehensive information about the molecular and cellular changes produced by UUO. Magn Reson Med 79:2216-2227, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Feng Wang
- Vanderbilt University Institute of Imaging Science, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Keiko Takahashi
- Division of Nephrology and Hypertension, Vanderbilt University, Nashville, Tennessee, USA
| | - Hua Li
- Vanderbilt University Institute of Imaging Science, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Zhongliang Zu
- Vanderbilt University Institute of Imaging Science, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Ke Li
- Vanderbilt University Institute of Imaging Science, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Junzhong Xu
- Vanderbilt University Institute of Imaging Science, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA.,Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Raymond C Harris
- Division of Nephrology and Hypertension, Vanderbilt University, Nashville, Tennessee, USA
| | - Takamune Takahashi
- Division of Nephrology and Hypertension, Vanderbilt University, Nashville, Tennessee, USA
| | - John C Gore
- Vanderbilt University Institute of Imaging Science, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA.,Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
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22
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Wang F, Zu Z, Wu R, Wu TL, Gore JC, Chen LM. MRI evaluation of regional and longitudinal changes in Z-spectra of injured spinal cord of monkeys. Magn Reson Med 2017; 79:1070-1082. [PMID: 28547862 DOI: 10.1002/mrm.26756] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 04/21/2017] [Accepted: 04/22/2017] [Indexed: 01/21/2023]
Abstract
PURPOSE In principle, MR methods that exploit magnetization transfer (MT) may be used to quantify changes in the molecular composition of tissues after injury. The ability to track such changes in injured spinal cord may allow more precise assessment of the state of neural tissues. METHODS Z-Spectra were obtained from the cervical spinal cord before and after a unilateral dorsal column lesion in monkeys at 9.4T. The amplitudes of chemical exchange saturation transfer (CEST) and nuclear Overhauser enhancement (NOE) effects from multiple proton pools, along with nonspecific semisolid MT effects from immobile macromolecules, were quantified using a five-peak Lorenzian fitting of each Z-spectrum. RESULTS Abnormal tissues/cysts that formed around lesion sites exhibited relatively low correlations between their Z-spectra and that of normal gray matter (GM). Compared with normal GM, cysts showed strong CEST but weak semisolid MT and NOE effects after injury. The abnormal tissues around lesion sites were heterogeneous and showed different regional Z-spectra. Different regional correlations between proton pools were observed. Longitudinally, injured spinal cord tissue exhibited remarkable recovery in all subjects. CONCLUSION Characterization of multiple proton pools from Z-spectra permitted noninvasive, regional, quantitative assessments of changes in tissue composition of injured spinal cord over time. Magn Reson Med 79:1070-1082, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Feng Wang
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Zhongliang Zu
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Ruiqi Wu
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Tung-Lin Wu
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.,Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - John C Gore
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA.,Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Li Min Chen
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
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23
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Wang F, Kopylov D, Zu Z, Takahashi K, Wang S, Quarles CC, Gore JC, Harris RC, Takahashi T. Mapping murine diabetic kidney disease using chemical exchange saturation transfer MRI. Magn Reson Med 2015; 76:1531-1541. [PMID: 26608660 DOI: 10.1002/mrm.26045] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 10/17/2015] [Accepted: 10/21/2015] [Indexed: 12/27/2022]
Abstract
PURPOSE Diabetic nephropathy (DN) is the leading cause of renal failure; however, current clinical tests are insufficient for assessing this disease. DN is associated with changes in renal metabolites, so we evaluated the utility of chemical exchange saturation transfer (CEST) imaging to detect changes characteristic of this disease. METHODS Sensitivity of CEST imaging at 7 Tesla to DN was evaluated by imaging diabetic mice [db/db, db/db endothelial nitric oxide synthase (eNOS)-/-] that show different levels of nephropathy as well as by longitudinal imaging (8 to 24 weeks). Nondiabetic (db/m) mice were used as controls. RESULTS Compared with nondiabetic mice, the CEST contrasts of hydroxyl metabolites that correspond to glucose and glycogen were significantly increased in papilla (P), inner medulla (IM), and outer medulla (OM) in db/db and db/db eNOS-/- kidneys at 16 weeks. The db/db eNOS-/- mice that showed advanced nephropathy exhibited greater CEST effects in OM and significant CEST contrasts were also observed in cortex. Longitudinally, db/db mice exhibited progressive increases in hydroxyl signals in IM+P and OM from 12 to 24 weeks and an increase was also observed in cortex at 24 weeks. CONCLUSION CEST MRI can be used to measure changes of hydroxyl metabolites in kidney during progression of DN. Magn Reson Med 76:1531-1541, 2016. © 2015 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Feng Wang
- Vanderbilt University Institute of Imaging Science, Tennessee, USA. .,Radiology and Radiological Sciences, Vanderbilt University, Tennessee, USA.
| | - David Kopylov
- Drexel University College of Medicine, Pennsylvania, USA
| | - Zhongliang Zu
- Vanderbilt University Institute of Imaging Science, Tennessee, USA.,Radiology and Radiological Sciences, Vanderbilt University, Tennessee, USA
| | - Keiko Takahashi
- Division of Nephrology and Hypertension, Vanderbilt University, Tennessee, USA
| | - Suwan Wang
- Division of Nephrology and Hypertension, Vanderbilt University, Tennessee, USA
| | - C Chad Quarles
- Vanderbilt University Institute of Imaging Science, Tennessee, USA.,Radiology and Radiological Sciences, Vanderbilt University, Tennessee, USA
| | - John C Gore
- Vanderbilt University Institute of Imaging Science, Tennessee, USA.,Radiology and Radiological Sciences, Vanderbilt University, Tennessee, USA.,Biomedical Engineering, Vanderbilt University, Tennessee, USA
| | - Raymond C Harris
- Division of Nephrology and Hypertension, Vanderbilt University, Tennessee, USA
| | - Takamune Takahashi
- Division of Nephrology and Hypertension, Vanderbilt University, Tennessee, USA
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24
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Zhang C, Morozova AY, Abakumov MA, Gubsky IL, Douglas P, Feng S, Bryukhovetskiy AS, Chekhonin VP. Precise Delivery Into Chronic Spinal Cord Injury Syringomyelic Cysts with Magnetic Nanoparticles MRI Visualization. Med Sci Monit 2015; 21:3179-85. [PMID: 26486048 PMCID: PMC4621156 DOI: 10.12659/msm.895624] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 10/02/2015] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Traumatic spinal cord injury (SCI) often results in the deficiency of glia and neurons in cystic cavities. These syringomyelic cysts can prevent axonal regeneration and sprouting. Details of the mechanism of syringomyelic cyst formation are unknown and an effective treatment for overcoming syringomyelic cysts is not available. MATERIAL AND METHODS Ten adult female Wistar rats underwent contusion SCI modeling resulting in syringomyelic cyst formation. A novel method for locating the cysts was developed and employed. MRI safe silver needles were inserted through the erector spinae of anesthetized rats to create a stable reference point. MRI images of the rodent spine were taken with the needles in situ. This information was used to accurately locate the cyst and determine the 3-dimensional entry point coordinates for nanoparticle delivery. Nanoparticles were injected into the cyst during a primary injection of 8 ul and a secondary injection of 8 ul, to prove the procedure can be accurately repeated. RESULTS None of the rats died intra- or post-operatively. The syringomyelic cysts were accurately located with the 3-dimensional entry point coordinates. After nanoparticle delivery twice into each rat, the visualized syringomyelic cyst volume significantly decreased from 5.71±0.21 mm3 to 3.23±0.364 mm3 and to 1.48±0.722 mm3. CONCLUSIONS The present study describes a novel strategy for precise nanoparticle delivery into a syringomyelic cyst, using measurements obtained from MRI images. This strategy may aid in developing a new method for studying chronic spinal cord injury and a novel treatment for syringomyelic cysts.
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Affiliation(s)
- Chao Zhang
- Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin, P.R. China
- Department of Medicinal Nanobiotechnology, Pirogov Russian National Research Medical University, Moscow, Russian Federation
- Department of Basic and Applied Neurobiology, Federal Medical Research Center for Psychiatry and Narcology, Moscow, Russian Federation
| | - Anna Y. Morozova
- Department of Basic and Applied Neurobiology, Federal Medical Research Center for Psychiatry and Narcology, Moscow, Russian Federation
| | - Maxim A. Abakumov
- Department of Medicinal Nanobiotechnology, Pirogov Russian National Research Medical University, Moscow, Russian Federation
| | - Ilya L. Gubsky
- Department of Medicinal Nanobiotechnology, Pirogov Russian National Research Medical University, Moscow, Russian Federation
| | - Patricia Douglas
- Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin, P.R. China
| | - Shiqing Feng
- Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin, P.R. China
| | - Andrey S. Bryukhovetskiy
- Center for Biomedical Technologies, Federal Research and Clinical Center for Specialized Types of Medical Assistance and Medical Technologies of The Federal Medical Biological Agency, Moscow, Russian Federation
| | - Vladimir P. Chekhonin
- Department of Medicinal Nanobiotechnology, Pirogov Russian National Research Medical University, Moscow, Russian Federation
- Department of Basic and Applied Neurobiology, Federal Medical Research Center for Psychiatry and Narcology, Moscow, Russian Federation
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25
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Differential fMRI Activation Patterns to Noxious Heat and Tactile Stimuli in the Primate Spinal Cord. J Neurosci 2015. [PMID: 26203144 DOI: 10.1523/jneurosci.0583-15.2015] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Mesoscale local functional organizations of the primate spinal cord are largely unknown. Using high-resolution fMRI at 9.4 T, we identified distinct interhorn and intersegment fMRI activation patterns to tactile versus nociceptive heat stimulation of digits in lightly anesthetized monkeys. Within a spinal segment, 8 Hz vibrotactile stimuli elicited predominantly fMRI activations in the middle part of ipsilateral dorsal horn (iDH), along with significantly weaker activations in ipsilateral (iVH) and contralateral (cVH) ventral horns. In contrast, nociceptive heat stimuli evoked widespread strong activations in the superficial part of iDH, as well as in iVH and contralateral dorsal (cDH) horns. As controls, only weak signal fluctuations were detected in the white matter. The iDH responded most strongly to both tactile and heat stimuli, whereas the cVH and cDH responded selectively to tactile versus nociceptive heat, respectively. Across spinal segments, iDH activations were detected in three consecutive segments in both tactile and heat conditions. Heat responses, however, were more extensive along the cord, with strong activations in iVH and cDH in two consecutive segments. Subsequent subunit B of cholera toxin tracer histology confirmed that the spinal segments showing fMRI activations indeed received afferent inputs from the stimulated digits. Comparisons of the fMRI signal time courses in early somatosensory area 3b and iDH revealed very similar hemodynamic stimulus-response functions. In summary, we identified with fMRI distinct segmental networks for the processing of tactile and nociceptive heat stimuli in the cervical spinal cord of nonhuman primates. Significance statement: This is the first fMRI demonstration of distinct intrasegmental and intersegmental nociceptive heat and touch processing circuits in the spinal cord of nonhuman primates. This study provides novel insights into the local functional organizations of the primate spinal cord for pain and touch, information that will be valuable for designing and optimizing therapeutic interventions for chronic pain management.
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26
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Wang F, Li K, Mishra A, Gochberg D, Min Chen L, Gore JC. Longitudinal assessment of spinal cord injuries in nonhuman primates with quantitative magnetization transfer. Magn Reson Med 2015; 75:1685-96. [PMID: 25960050 DOI: 10.1002/mrm.25725] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 03/16/2015] [Accepted: 03/20/2015] [Indexed: 01/15/2023]
Abstract
PURPOSE This study aimed to evaluate the reproducibility and specificity of quantitative magnetization transfer (qMT) imaging for monitoring spinal cord injuries (SCIs). METHODS MRI scans were performed in anesthetized monkeys at 9.4T, before and serially after a unilateral lesion of the cervical spinal cord. A two-pool fitting model was used to derive qMT parameters. RESULTS qMT measures were reproducible across normal subjects, with an average pool size ratio (PSR) of 0.086 ± 0.003 (mean ± SD) for gray matter, and 0.120 ± 0.005 for white matter, respectively. Compared with normal gray matter, the PSR of abnormal tissues rostral and caudal to the injury site decreased by 19.5% (P < 0.05), while the PSR of the cyst-like volume decreased drastically weeks after SCI. Strong correlations in cyst-like regions were observed between PSR and other MRI measures including longitudinal relaxation rate (R1 ), apparent diffusion coefficient and fractional anisotropy (FA). Decreased PSR and FA values correlated well with demyelination in abnormal tissues. CONCLUSION The qMT parameters provide robust and specific information about the molecular and cellular changes produced by SCI. PSR detected demyelination and loss of macromolecules in abnormal tissue regions rostral and caudal to the cyst/lesion sites.
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Affiliation(s)
- Feng Wang
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.,Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Ke Li
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.,Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Arabinda Mishra
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.,Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Daniel Gochberg
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.,Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Li Min Chen
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.,Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA.,Psychology, Vanderbilt University, Nashville, Tennessee, USA
| | - John C Gore
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.,Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA.,Psychology, Vanderbilt University, Nashville, Tennessee, USA.,Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
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