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Zheng LX, Yu Q, Li Q, Zheng CD. Targeted local anesthesia: a novel slow-release Fe 3O 4-lidocaine-PLGA microsphere endowed with a magnetic targeting function. J Anesth 2024; 38:232-243. [PMID: 38310577 DOI: 10.1007/s00540-023-03305-1] [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: 06/28/2023] [Accepted: 12/25/2023] [Indexed: 02/06/2024]
Abstract
PURPOSE Lidocaine microspheres can prolong the analgesic time to 24-48 h, which still cannot meet the need of postoperative analgesia lasting more than 3 days. Therefore, we added Fe3O4 to the lidocaine microspheres and used an applied magnetic field to attract Fe3O4 to fix the microspheres around the target nerves, reducing the diffusion of magnetic lidocaine microspheres to the surrounding tissues and prolonging the analgesic time. METHODS Fe3O4-lidocaine-PLGA microspheres were prepared by the complex-emulsion volatilization method to characterize and study the release properties in vitro. The neural anchoring properties and in vivo morphology of the drug were obtained by magnetic resonance imaging. The nerve blocking effect and analgesic effect of magnetic lidocaine microspheres were evaluated by animal experiments. RESULTS The mean diameter of magnetically responsive lidocaine microspheres: 9.04 ± 3.23 μm. The encapsulation and drug loading of the microspheres were 46.18 ± 3.26% and 6.02 ± 1.87%, respectively. Magnetic resonance imaging showed good imaging of Fe3O4-Lidocain-PLGA microspheres, a drug-carrying model that slowed down the diffusion of the microspheres in the presence of an applied magnetic field. Animal experiments demonstrated that this preparation had a significantly prolonged nerve block, analgesic effect, and a nerve anchoring function. CONCLUSION Magnetically responsive lidocaine microspheres can prolong analgesia by slowly releasing lidocaine, which can be immobilized around the nerve by a magnetic field on the body surface, avoiding premature diffusion of the microspheres to surrounding tissues and improving drug targeting.
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Affiliation(s)
- Ling-Xi Zheng
- Institute of Biomedical Engineering, College of Medicine, Southwest Jiaotong University, Chengdu, 610031, Sichuan, China
| | - Qian Yu
- Institute of Biomedical Engineering, College of Medicine, Southwest Jiaotong University, Chengdu, 610031, Sichuan, China
| | - Qiang Li
- Department of Anesthesiology, The Third People's Hospital of Chengdu, Affiliated Hospital of Southwest Jiaotong University, 19 Yangshi Street, Qingyang District, Chengdu, 610031, Sichuan, China
| | - Chuan-Dong Zheng
- Institute of Biomedical Engineering, College of Medicine, Southwest Jiaotong University, Chengdu, 610031, Sichuan, China.
- Department of Anesthesiology, The Third People's Hospital of Chengdu, Affiliated Hospital of Southwest Jiaotong University, 19 Yangshi Street, Qingyang District, Chengdu, 610031, Sichuan, China.
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2
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Nair AK, Adluru N, Finley AJ, Gresham LK, Skinner SE, Alexander AL, Davidson RJ, Ryff CD, Schaefer SM. Purpose in life as a resilience factor for brain health: diffusion MRI findings from the Midlife in the U.S. study. Front Psychiatry 2024; 15:1355998. [PMID: 38505799 PMCID: PMC10948414 DOI: 10.3389/fpsyt.2024.1355998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 02/09/2024] [Indexed: 03/21/2024] Open
Abstract
Introduction A greater sense of purpose in life is associated with several health benefits relevant for active aging, but the mechanisms remain unclear. We evaluated if purpose in life was associated with indices of brain health. Methods We examined data from the Midlife in the United States (MIDUS) Neuroscience Project. Diffusion weighted magnetic resonance imaging data (n=138; mean age 65.2 years, age range 48-95; 80 females; 37 black, indigenous, and people of color) were used to estimate microstructural indices of brain health such as axonal density, and axonal orientation. The seven-item purpose in life scale was used. Permutation analysis of linear models was used to examine associations between purpose in life scores and the diffusion metrics in white matter and in the bilateral hippocampus, adjusting for age, sex, education, and race. Results and discussion Greater sense of purpose in life was associated with brain microstructural features consistent with better brain health. Positive associations were found in both white matter and the right hippocampus, where multiple convergent associations were detected. The hippocampus is a brain structure involved in learning and memory that is vulnerable to stress but retains the capacity to grow and adapt through old age. Our findings suggest pathways through which an enhanced sense of purpose in life may contribute to better brain health and promote healthy aging. Since purpose in life is known to decline with age, interventions and policy changes that facilitate a greater sense of purpose may extend and improve the brain health of individuals and thus improve public health.
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Affiliation(s)
- Ajay Kumar Nair
- Institute on Aging, University of Wisconsin-Madison, Madison, WI, United States
| | - Nagesh Adluru
- Waisman Center, University of Wisconsin-Madison, Madison, WI, United States
- Department of Radiology, University of Wisconsin-Madison, Madison, WI, United States
| | - Anna J. Finley
- Institute on Aging, University of Wisconsin-Madison, Madison, WI, United States
| | - Lauren K. Gresham
- Institute on Aging, University of Wisconsin-Madison, Madison, WI, United States
| | - Sarah E. Skinner
- Institute on Aging, University of Wisconsin-Madison, Madison, WI, United States
| | - Andrew L. Alexander
- Waisman Center, University of Wisconsin-Madison, Madison, WI, United States
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, United States
| | - Richard J. Davidson
- Center for Healthy Minds, University of Wisconsin-Madison, Madison, WI, United States
| | - Carol D. Ryff
- Institute on Aging, University of Wisconsin-Madison, Madison, WI, United States
| | - Stacey M. Schaefer
- Institute on Aging, University of Wisconsin-Madison, Madison, WI, United States
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Jung JY, Lin Y, Carrino JA. An Updated Review of Magnetic Resonance Neurography for Plexus Imaging. Korean J Radiol 2023; 24:1114-1130. [PMID: 37899521 PMCID: PMC10613850 DOI: 10.3348/kjr.2023.0150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 08/02/2023] [Accepted: 08/06/2023] [Indexed: 10/31/2023] Open
Abstract
Magnetic resonance neurography (MRN) is increasingly used to visualize peripheral nerves in vivo. However, the implementation and interpretation of MRN in the brachial and lumbosacral plexi are challenging because of the anatomical complexity and technical limitations. The purpose of this article was to review the clinical context of MRN, describe advanced magnetic resonance (MR) techniques for plexus imaging, and list the general categories of utility of MRN with pertinent imaging examples. The selection and optimization of MR sequences are centered on the homogeneous suppression of fat and blood vessels while enhancing the visibility of the plexus and its branches. Standard 2D fast spin-echo sequences are essential to assess morphology and signal intensity of nerves. Moreover, nerve-selective 3D isotropic images allow improved visualization of nerves and multiplanar reconstruction along their course. Diffusion-weighted and diffusion-tensor images offer microscopic and functional insights into peripheral nerves. The interpretation of MRN in the brachial and lumbosacral plexi should be based on a thorough understanding of their anatomy and pathophysiology. Anatomical landmarks assist in identifying brachial and lumbosacral plexus components of interest. Thus, understanding the varying patterns of nerve abnormalities facilitates the interpretation of aberrant findings.
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Affiliation(s)
- Joon-Yong Jung
- Department of Radiology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Yenpo Lin
- Department of Radiology and Imaging, Hospital for Special Surgery, Weill Cornell Medicine, New York, NY, USA
- Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - John A Carrino
- Department of Radiology and Imaging, Hospital for Special Surgery, Weill Cornell Medicine, New York, NY, USA.
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Simultaneous Quantification of Anisotropic Microcirculation and Microstructure in Peripheral Nerve. J Clin Med 2022; 11:jcm11113036. [PMID: 35683424 PMCID: PMC9181650 DOI: 10.3390/jcm11113036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 05/16/2022] [Accepted: 05/25/2022] [Indexed: 02/04/2023] Open
Abstract
Peripheral nerve injury is a significant public health challenge, and perfusion in the nerve is a potential biomarker for assessing the injury severity and prognostic outlook. Here, we applied a novel formalism that combined intravoxel incoherent motion (IVIM) and diffusion tensor imaging (DTI) to simultaneously characterize anisotropic microcirculation and microstructure in the rat sciatic nerve. Comparison to postmortem measurements revealed that the in vivo IVIM-DTI signal contained a fast compartment (2.32 ± 0.04 × 10−3 mm2/s mean diffusivity, mean ± sem, n = 6, paired t test p < 0.01) that could be attributed to microcirculation in addition to a slower compartment that had similar mean diffusivity as the postmortem nerve (1.04 ± 0.01 vs. 0.96 ± 0.05 × 10−3 mm2/s, p > 0.05). Although further investigation and technical improvement are warranted, this preliminary study demonstrates both the feasibility and potential for applying the IVIM-DTI methodology to peripheral nerves for quantifying perfusion in the presence of anisotropic tissue microstructure.
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Awais K, Snoj Ž, Cvetko E, Serša I. Diffusion Tensor Imaging of a Median Nerve by Magnetic Resonance: A Pilot Study. Life (Basel) 2022; 12:life12050748. [PMID: 35629414 PMCID: PMC9143877 DOI: 10.3390/life12050748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 05/12/2022] [Accepted: 05/16/2022] [Indexed: 12/03/2022] Open
Abstract
The magnetic resonance Diffusion Tensor Imaging (DTI) is a powerful extension of Diffusion Weighted Imaging (DWI) utilizing multiple bipolar gradients, allowing for the evaluation of the microstructural environment of the highly anisotropic tissues. DTI was predominantly used for the assessment of the central nervous system (CNS), but with the advancement in magnetic resonance (MR) hardware and software, it has now become possible to image the peripheral nerves which were difficult to evaluate previously because of their small caliber. This study focuses on the assessment of the human median peripheral nerve ex vivo by DTI microscopy at 9.4 T magnetic field which allowed the evaluation of diffusion eigenvalues, the mean diffusivity and the fractional anisotropy at 35 μm in-plane resolution. The resolution was sufficient for clear depiction of all nerve anatomical structures and therefore further image analysis allowed the obtaining of average values for DT parameters in nerve fascicles (intrafascicular region and perineurium) as well as in the surrounding epineurium. The results confirmed the highest fractional anisotropy of 0.33 and principal diffusion eigenvalue of 1.0 × 10−9 m2/s in the intrafascicular region, somewhat lower values of 0.27 and 0.95 × 10−9 m2/s in the perineurium region and close to isotropic with very slow diffusion (0.15 and 0.05 × 10−9 m2/s) in the epineurium region.
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Affiliation(s)
- Kanza Awais
- Jožef Stefan International Postgraduate School, 1000 Ljubljana, Slovenia;
| | - Žiga Snoj
- Department of Radiology, University Medical Centre Ljubljana, 1000 Ljubljana, Slovenia;
| | - Erika Cvetko
- Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia;
| | - Igor Serša
- Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia;
- Jožef Stefan Institute, 1000 Ljubljana, Slovenia
- Correspondence: ; Tel.: +386-1-477-3696
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Roca FG, Santos LG, Roig MM, Medina LM, Martínez-Ramos C, Pradas MM. Novel Tissue-Engineered Multimodular Hyaluronic Acid-Polylactic Acid Conduits for the Regeneration of Sciatic Nerve Defect. Biomedicines 2022; 10:biomedicines10050963. [PMID: 35625700 PMCID: PMC9138968 DOI: 10.3390/biomedicines10050963] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 04/14/2022] [Accepted: 04/18/2022] [Indexed: 02/01/2023] Open
Abstract
The gold standard for the treatment of peripheral nerve injuries, the autograft, presents several drawbacks, and engineered constructs are currently suitable only for short gaps or small diameter nerves. Here, we study a novel tissue-engineered multimodular nerve guidance conduit for the treatment of large nerve damages based in a polylactic acid (PLA) microfibrillar structure inserted inside several co-linear hyaluronic acid (HA) conduits. The highly aligned PLA microfibers provide a topographical cue that guides axonal growth, and the HA conduits play the role of an epineurium and retain the pre-seeded auxiliary cells. The multimodular design increases the flexibility of the device. Its performance for the regeneration of a critical-size (15 mm) rabbit sciatic nerve defect was studied and, after six months, very good nerve regeneration was observed. The multimodular approach contributed to a better vascularization through the micrometrical gaps between HA conduits, and the pre-seeded Schwann cells increased axonal growth. Six months after surgery, a cross-sectional available area occupied by myelinated nerve fibers above 65% at the central and distal portions was obtained when the multimodular device with pre-seeded Schwann cells was employed. The results validate the multi-module approach for the regeneration of large nerve defects and open new possibilities for surgical solutions in this field.
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Affiliation(s)
- Fernando Gisbert Roca
- Center for Biomaterials and Tissue Engineering, Universitat Politècnica de València, 46022 Valencia, Spain; (F.G.R.); (L.G.S.); (C.M.-R.)
| | - Luis Gil Santos
- Center for Biomaterials and Tissue Engineering, Universitat Politècnica de València, 46022 Valencia, Spain; (F.G.R.); (L.G.S.); (C.M.-R.)
| | - Manuel Mata Roig
- Department of Pathology, Faculty of Medicine and Dentistry, Universitat de València, 46010 Valencia, Spain; (M.M.R.); (L.M.M.)
| | - Lara Milian Medina
- Department of Pathology, Faculty of Medicine and Dentistry, Universitat de València, 46010 Valencia, Spain; (M.M.R.); (L.M.M.)
| | - Cristina Martínez-Ramos
- Center for Biomaterials and Tissue Engineering, Universitat Politècnica de València, 46022 Valencia, Spain; (F.G.R.); (L.G.S.); (C.M.-R.)
- Unitat Predepartamental de Medicina, Universitat Jaume I, 12071 Castellón de la Plana, Spain
| | - Manuel Monleón Pradas
- Center for Biomaterials and Tissue Engineering, Universitat Politècnica de València, 46022 Valencia, Spain; (F.G.R.); (L.G.S.); (C.M.-R.)
- Biomedical Research Networking Center in Bioengineering Biomaterials and Nanomedicine (CIBER-BBN), 28029 Madrid, Spain
- Correspondence: ; Tel.: +34-963-877000
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7
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Martín-Noguerol T, Barousse R, Luna A, Socolovsky M, Górriz JM, Gómez-Río M. New insights into the evaluation of peripheral nerves lesions: a survival guide for beginners. Neuroradiology 2022; 64:875-886. [PMID: 35212785 DOI: 10.1007/s00234-022-02916-x] [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: 11/11/2021] [Accepted: 02/09/2022] [Indexed: 12/09/2022]
Abstract
PURPOSE To perform a review of the physical basis of DTI and DCE-MRI applied to Peripheral Nerves (PNs) evaluation with the aim of providing readers the main concepts and tools to acquire these types of sequences for PNs assessment. The potential added value of these advanced techniques for pre-and post-surgical PN assessment is also reviewed in diverse clinical scenarios. Finally, a brief introduction to the promising applications of Artificial Intelligence (AI) for PNs evaluation is presented. METHODS We review the existing literature and analyze the latest evidence regarding DTI, DCE-MRI and AI for PNs assessment. This review is focused on a practical approach to these advanced sequences providing tips and tricks for implementing them into real clinical practice focused on imaging postprocessing and their current clinical applicability. A summary of the potential applications of AI algorithms for PNs assessment is also included. RESULTS DTI, successfully used in central nervous system, can also be applied for PNs assessment. DCE-MRI can help evaluate PN's vascularization and integrity of Blood Nerve Barrier beyond the conventional gadolinium-enhanced MRI sequences approach. Both approaches have been tested for PN assessment including pre- and post-surgical evaluation of PNs and tumoral conditions. AI algorithms may help radiologists for PN detection, segmentation and characterization with promising initial results. CONCLUSION DTI, DCE-MRI are feasible tools for the assessment of PN lesions. This manuscript emphasizes the technical adjustments necessary to acquire and post-process these images. AI algorithms can also be considered as an alternative and promising choice for PN evaluation with promising results.
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Affiliation(s)
| | - Rafael Barousse
- Peripheral Nerve and Plexus Department, Centro Rossi, Sánchez de Loria 117, C1173 AAC, Buenos Aires, Argentina
| | - Antonio Luna
- MRI unit, Radiology Department, HT Medica, Carmelo Torres 2, 23007, Jaén, Spain
| | - Mariano Socolovsky
- Nerve & Plexus Surgery Program, Division of Neurosurgery, Hospital de Clínicas, University of Buenos Aires School of Medicine, Paraguay 2155, C1121 ABG, Buenos Aires, Argentina
| | - Juan M Górriz
- Department of Signal Theory, Networking and Communications, University of Granada, Avenida de Fuente Nueva, s/n, 18071, Granada, Spain.,Department of Psychiatry, University of Cambridge, Cambridge, CB21TN, UK
| | - Manuel Gómez-Río
- Department of Nuclear Medicine, Virgen de las Nieves University Hospital, Av. de las Fuerzas Armadas, 2, 18014, Granada, Spain.,IBS Granada Bio-Health Research Institute, Av. de Madrid, 15, 18012, Granada, Spain
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8
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Merolli A, Li M, Voronin G, Bright L. A sciatic nerve gap-injury model in the rabbit. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2022; 33:14. [PMID: 35061121 PMCID: PMC8782784 DOI: 10.1007/s10856-022-06642-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 12/23/2021] [Indexed: 06/14/2023]
Abstract
There has been an increased number of studies of nerve transection injuries with the sciatic nerve gap-injury model in the rabbit in the past 2 years. We wanted to define in greater detail what is needed to test artificial nerve guides in a sciatic nerve gap-injury model in the rabbit. We hope that this will help investigators to fully exploit the robust translational potential of the rabbit sciatic nerve gap-injury model in its capacity to test devices whose diameter and length are in the range of those commonly applied in hand and wrist surgery (diameter ranging between 2 and 4 mm; length up to 30 mm). We suggest that the rabbit model should replace the less translational rat model in nerve regeneration research. The rabbit sciatic model, however, requires an effective strategy to prevent and control self-mutilation of the foot in the postoperative period, and to prevent pressure ulcers.
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Affiliation(s)
- Antonio Merolli
- Department of Physics and Astronomy, Rutgers-The State University of New Jersey, New Brunswick, NJ, USA.
- New Jersey Center for Biomaterials, Rutgers-The State University of New Jersey, New Brunswick, NJ, USA.
| | - Michelle Li
- New Jersey Center for Biomaterials, Rutgers-The State University of New Jersey, New Brunswick, NJ, USA
| | - Gregory Voronin
- In Vivo Research Services, Rutgers-The State University of New Jersey, New Brunswick, NJ, USA
| | - Lauren Bright
- Comparative Medicine Resources, Rutgers-The State University of New Jersey, New Brunswick, NJ, USA
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9
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Holmes SA, Karapanagou A, Staffa SJ, Zurakowski D, Borra R, Simons LE, Sieberg C, Lebel A, Borsook D. DTI and MTR Measures of Nerve Fiber Integrity in Pediatric Patients With Ankle Injury. Front Pediatr 2021; 9:656843. [PMID: 34660471 PMCID: PMC8511521 DOI: 10.3389/fped.2021.656843] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 08/18/2021] [Indexed: 11/13/2022] Open
Abstract
Acute peripheral nerve injury can lead to chronic neuropathic pain. Having a standardized, non-invasive method to evaluate pathological changes in a nerve following nerve injury would help with diagnostic and therapeutic assessments or interventions. The accurate evaluation of nerve fiber integrity after injury may provide insight into the extent of pathology and a patient's level of self-reported pain. The aim of this investigation was to evaluate the extent to which peripheral nerve integrity could be evaluated in an acute ankle injury cohort and how markers of nerve fiber integrity correlate with self-reported pain levels in afferent nerves. We recruited 39 pediatric participants with clinically defined neuropathic pain within 3 months of an ankle injury and 16 healthy controls. Participants underwent peripheral nerve MRI using diffusion tensor (DTI) and magnetization transfer imaging (MTI) of their injured and non-injured ankles. The imaging window was focused on the branching point of the sciatic nerve into the tibial and fibular division. Each participant completed the Pain Detection Questionnaire (PDQ). Findings demonstrated group differences in DTI and MTI in the sciatic, tibial and fibular nerve in the injured ankle relative to healthy control and contralateral non-injured nerve fibers. Only AD and RD from the injured fibular nerve correlated with PDQ scores which coincides with the inversion-dominant nature of this particular ankle injuruy cohort. Exploratory analyses highlight the potential remodeling stages of nerve injury from neuropathic pain. Future research should emphasize sub-acute time frames of injury to capture post-injury inflammation and nerve fiber recovery.
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Affiliation(s)
- Scott A. Holmes
- Center for Pain and the Brain, Boston Children's Hospital, Boston, MA, United States
- Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital and Harvard Medical School, Boston, MA, United States
| | - Anastasia Karapanagou
- Center for Pain and the Brain, Boston Children's Hospital, Boston, MA, United States
- Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital and Harvard Medical School, Boston, MA, United States
| | - Steven J. Staffa
- Center for Pain and the Brain, Boston Children's Hospital, Boston, MA, United States
- Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital and Harvard Medical School, Boston, MA, United States
| | - David Zurakowski
- Center for Pain and the Brain, Boston Children's Hospital, Boston, MA, United States
- Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital and Harvard Medical School, Boston, MA, United States
| | - Ronald Borra
- Department of Radiology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Laura E. Simons
- Department of Anesthesia, Stanford University, Stanford, CA, United States
| | - Christine Sieberg
- Center for Pain and the Brain, Boston Children's Hospital, Boston, MA, United States
- Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital and Harvard Medical School, Boston, MA, United States
| | - Alyssa Lebel
- Center for Pain and the Brain, Boston Children's Hospital, Boston, MA, United States
- Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital and Harvard Medical School, Boston, MA, United States
| | - David Borsook
- Center for Pain and the Brain, Boston Children's Hospital, Boston, MA, United States
- Departments of Psychiatry and Radiology, Massachusetts General Hospital, Boston, MA, United States
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10
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Wan Q, Yu Y, Bao Y, Hu J, Wang P, Peng Y, Xia X, Liao Y, Liu J, Xie X, Li X. Evaluation of peripheral nerve acute crush injury in rabbits: comparison among diffusion kurtosis imaging, diffusion tensor imaging and electromyography. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2021; 35:291-299. [PMID: 34374905 DOI: 10.1007/s10334-021-00952-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 05/01/2021] [Accepted: 08/05/2021] [Indexed: 11/24/2022]
Abstract
OBJECTIVE Diffusion kurtosis imaging (DKI) has been proven to provide additional value for assessing many central nervous system diseases compared with conventional diffusion tensor imaging (DTI); however, whether it has the same value in peripheral nerve injury is unclear. This study aimed to investigate the performance of DKI, DTI, and electromyography (EMG) in evaluating peripheral nerve crush injury (PNCI) in rabbits. MATERIALS AND METHODS A total of 27 New Zealand white rabbits were selected to establish a PNCI model. Longitudinal DTI, DKI, and EMG were evaluated before surgery and 1 day, 3 days, 1 week, 2 weeks, 4 weeks, 6 weeks, and 8 weeks after surgery. At each time point, two rabbits were randomly selected for pathological examination. RESULTS The results showed that fractional anisotropy (FA) derived from both DKI and DTI demonstrated a significant difference between injured and control nerves at all time points (all P < 0.005) mean kurtosis of the injured nerve was lower than that on the control side after 2-8 weeks (all P < 0.05). No statistically significant difference was found in radial kurtosis, axial kurtosis, and apparent diffusion coefficient at almost every time point. The difference in compound muscle action potential (CMAP) of the bilateral gastrocnemius at each time point was statistically significant (all P < 0.001). CONCLUSIONS CMAP was a sensitive and reliable method to assess acute PNCI without being affected by perineural edema. DKI may not be superior to DTI in evaluating peripheral nerves, DTI with a shorter scanning time was preferred as an effective choice for evaluating acute peripheral nerve traumatic injury.
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Affiliation(s)
- Qi Wan
- Department of Radiology, The First Affiliated Hospital of Guangzhou Medical University, Yanjiangxilu No. 151, Guangzhou, 510120, China
| | - Yudong Yu
- Department of Radiology, The First Affiliated Hospital of Guangzhou Medical University, Yanjiangxilu No. 151, Guangzhou, 510120, China.,Department of Radiology, Huizhou Central People's Hospital, Huizhou, China
| | - Yingying Bao
- Department of Radiology, The First Affiliated Hospital of Guangzhou Medical University, Yanjiangxilu No. 151, Guangzhou, 510120, China
| | - Jianfeng Hu
- Department of Radiology, The First Affiliated Hospital of Guangzhou Medical University, Yanjiangxilu No. 151, Guangzhou, 510120, China
| | - Peng Wang
- Department of Radiology, The First Affiliated Hospital of Guangzhou Medical University, Yanjiangxilu No. 151, Guangzhou, 510120, China
| | - Yu Peng
- Department of Radiology, The First Affiliated Hospital of Guangzhou Medical University, Yanjiangxilu No. 151, Guangzhou, 510120, China
| | - Xiaoying Xia
- Department of Radiology, The First Affiliated Hospital of Guangzhou Medical University, Yanjiangxilu No. 151, Guangzhou, 510120, China
| | | | - Jieqiong Liu
- Department of Radiology, The First Affiliated Hospital of Guangzhou Medical University, Yanjiangxilu No. 151, Guangzhou, 510120, China
| | - Xiaobin Xie
- Department of Radiology, The First Affiliated Hospital of Guangzhou Medical University, Yanjiangxilu No. 151, Guangzhou, 510120, China
| | - Xinchun Li
- Department of Radiology, The First Affiliated Hospital of Guangzhou Medical University, Yanjiangxilu No. 151, Guangzhou, 510120, China.
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11
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Walker MR, Zhong J, Waspe AC, Piorkowska K, Nguyen LN, Anastakis DJ, Drake JM, Hodaie M. Peripheral Nerve Focused Ultrasound Lesioning-Visualization and Assessment Using Diffusion Weighted Imaging. Front Neurol 2021; 12:673060. [PMID: 34305786 PMCID: PMC8299784 DOI: 10.3389/fneur.2021.673060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 06/18/2021] [Indexed: 11/13/2022] Open
Abstract
Objectives: Magnetic resonance-guided focused ultrasound (MRgFUS) is a non-invasive targeted tissue ablation technique that can be applied to the nervous system. Diffusion weighted imaging (DWI) can visualize and evaluate nervous system microstructure. Tractography algorithms can reconstruct fiber bundles which can be used for treatment navigation and diffusion tensor imaging (DTI) metrics permit the quantitative assessment of nerve microstructure in vivo. There is a need for imaging tools to aid in the visualization and quantitative assessment of treatment-related nerve changes in MRgFUS. We present a method of peripheral nerve tract reconstruction and use DTI metrics to evaluate the MRgFUS treatment effect. Materials and Methods: MRgFUS was applied bilaterally to the sciatic nerves in 6 piglets (12 nerves total). T1-weighted and diffusion images were acquired before and after treatment. Tensor-based and constrained spherical deconvolution (CSD) tractography algorithms were used to reconstruct the nerves. DTI metrics of fractional anisotropy (FA), and mean (MD), axial (AD), and radial diffusivities (RD) were measured to assess acute (<1-2 h) treatment effects. Temperature was measured in vivo via MR thermometry. Histological data was collected for lesion assessment. Results: The sciatic nerves were successfully reconstructed in all subjects. Tract disruption was observed after treatment using both CSD and tensor models. DTI metrics in the targeted nerve segments showed significantly decreased FA and increased MD, AD, and RD. Transducer output power was positively correlated with lesion volume and temperature and negatively correlated with MD, AD, and RD. No correlations were observed between FA and other measured parameters. Conclusions: DWI and tractography are effective tools for visualizing peripheral nerve segments for targeting in non-invasive surgical methods and for assessing the microstructural changes that occur following MRgFUS treatment.
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Affiliation(s)
- Matthew R Walker
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada.,Division of Brain, Imaging & Behaviour, Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Jidan Zhong
- Division of Brain, Imaging & Behaviour, Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Adam C Waspe
- Centre for Image Guided Innovation and Therapeutic Intervention, Hospital for Sick Children, Toronto, ON, Canada.,Department of Medical Imaging, University of Toronto, Toronto, ON, Canada
| | - Karolina Piorkowska
- Centre for Image Guided Innovation and Therapeutic Intervention, Hospital for Sick Children, Toronto, ON, Canada
| | - Lananh N Nguyen
- Laboratory Medicine Program, University Health Network and University of Toronto, Toronto, ON, Canada
| | - Dimitri J Anastakis
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada.,Division of Brain, Imaging & Behaviour, Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Department of Surgery, Toronto Western Hospital, University Health Network and University of Toronto, Toronto, ON, Canada
| | - James M Drake
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada.,Centre for Image Guided Innovation and Therapeutic Intervention, Hospital for Sick Children, Toronto, ON, Canada.,Department of Neurosurgery, Hospital for Sick Children, Toronto, ON, Canada
| | - Mojgan Hodaie
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada.,Division of Brain, Imaging & Behaviour, Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Department of Neurosurgery, Toronto Western Hospital, University Health Network, Toronto, ON, Canada
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12
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Zheng C, Yang Z, Chen S, Zhang F, Rao Z, Zhao C, Quan D, Bai Y, Shen J. Nanofibrous nerve guidance conduits decorated with decellularized matrix hydrogel facilitate peripheral nerve injury repair. Am J Cancer Res 2021; 11:2917-2931. [PMID: 33456580 PMCID: PMC7806490 DOI: 10.7150/thno.50825] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Accepted: 12/21/2020] [Indexed: 12/15/2022] Open
Abstract
Rationale: Peripheral nerve injury (PNI) is a great challenge for regenerative medicine. Nerve autograft is the gold standard for clinical PNI repair. Due to its significant drawbacks, artificial nerve guidance conduits (NGCs) have drawn much attention as replacement therapies. We developed a combinatorial NGC consisting of longitudinally aligned electrospun nanofibers and porcine decellularized nerve matrix hydrogel (pDNM gel). The in vivo capacity for facilitating nerve tissue regeneration and functional recovery was evaluated in a rat sciatic nerve defect model. Methods: Poly (L-lactic acid) (PLLA) was electrospun into randomly oriented (PLLA-random) and longitudinally aligned (PLLA-aligned) nanofibers. PLLA-aligned were further coated with pDNM gel at concentrations of 0.25% (PLLA-aligned/0.25% pDNM gel) and 1% (PLLA-aligned/1% pDNM gel). Axonal extension and Schwann cells migration were evaluated by immunofluorescence staining of dorsal root ganglia cultured on the scaffolds. To fabricate implantable NGCs, the nanofibrous scaffolds were rolled and covered with an electrospun protection tube. The fabricated NGCs were then implanted into a 5 mm sciatic nerve defect model in adult male Sprague-Dawley rats. Nerves treated with NGCs were compared to contralateral uninjured nerves (control group), injured but untreated nerves (unstitched group), and autografted nerves. Nerve regeneration was monitored by an established set of assays, including T2 values and diffusion tensor imaging (DTI) derived from multiparametric magnetic resonance imaging (MRI), histological assessments, and immunostaining. Nerve functional recovery was evaluated by walking track analysis. Results: PLLA-aligned/0.25% pDNM gel scaffold exhibited the best performance in facilitating directed axonal extension and Schwann cells migration in vitro due to the combined effects of the topological cues provided by the aligned nanofibers and the biochemical cues retained in the pDNM gel. Consistent results were obtained in animal experiments with the fabricated NGCs. Both the T2 and fractional anisotropy values of the PLLA-aligned/0.25% pDNM gel group were the closest to those of the autografted group, and returned to normal much faster than those of the other NGCs groups. Histological assessment indicated that the implanted PLLA-aligned/0.25% pDNM gel NGC resulted in the largest number of axons and the most extensive myelination among all fabricated NGCs. Further, the PLLA-aligned/0.25% pDNM gel group exhibited the highest sciatic nerve function index, which was comparable to that of the autografted group, at 8 weeks post-surgery. Conclusions: NGCs composed of aligned PLLA nanofibers decorated with 0.25% pDNM gel provided both topological and biochemical guidance for directing and promoting axonal extension, nerve fiber myelination, and functional recovery. Moreover, T2-mapping and DTI metrics were found to be useful non-invasive monitoring techniques for PNI treatment.
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13
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Fertala J, Rivlin M, Wang ML, Beredjiklian PK, Steplewski A, Fertala A. Collagen-rich deposit formation in the sciatic nerve after injury and surgical repair: A study of collagen-producing cells in a rabbit model. Brain Behav 2020; 10:e01802. [PMID: 32924288 PMCID: PMC7559634 DOI: 10.1002/brb3.1802] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 06/16/2020] [Accepted: 07/28/2020] [Indexed: 12/22/2022] Open
Abstract
INTRODUCTION Posttraumatic scarring of peripheral nerves produces unwanted adhesions that block axonal growth. In the context of surgical nerve repair, the organization of the scar tissue adjacent to conduits used to span the gap between the stumps of transected nerves is poorly understood. The goal of this study was to elucidate the patterns of distribution of collagen-rich scar tissue and analyze the spatial organization of cells that produce fibrotic deposits around and within the conduit's lumen. METHODS Employing a rabbit model of sciatic nerve transection injury, we studied the formation of collagen-rich scar tissue both inside and outside conduits used to bridge the injury sites. Utilizing quantitative immunohistology and Fourier-transform infrared spectroscopy methods, we measured cellular and structural elements present in the extraneural and the intraneural scar of the proximal and distal nerve fragments. RESULTS Analysis of cells producing collagen-rich deposits revealed that alpha-smooth muscle actin-positive myofibroblasts were only present in the margins of the stumps. In contrast, heat shock protein 47-positive fibroblasts actively producing collagenous proteins were abundant within the entire scar tissue. The most prominent site of transected sciatic nerves with the highest number of cells actively producing collagen-rich scar was the proximal stump. CONCLUSION Our findings suggest the proximal region of the injury site plays a prominent role in pro-fibrotic processes associated with the formation of collagen-rich deposits. Moreover, they show that the role of canonical myofibroblasts in peripheral nerve regeneration is limited to wound contracture and that a distinct population of fibroblastic cells produce the collagenous proteins that form scar tissue. As scarring after nerve injury remains a clinical problem with poor outcomes due to incomplete nerve recovery, further elucidation of the cellular and spatial aspects of neural fibrosis will lead to more targeted treatments in the clinical setting.
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Affiliation(s)
- Jolanta Fertala
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
| | - Michael Rivlin
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA.,Rothman Institute of Orthopaedics, Thomas Jefferson University Hospital, Philadelphia, PA, USA
| | - Mark L Wang
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA.,Rothman Institute of Orthopaedics, Thomas Jefferson University Hospital, Philadelphia, PA, USA
| | - Pedro K Beredjiklian
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA.,Rothman Institute of Orthopaedics, Thomas Jefferson University Hospital, Philadelphia, PA, USA
| | - Andrzej Steplewski
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
| | - Andrzej Fertala
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
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14
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Role of diffusion tensor imaging of sciatic nerve in symptomatic patients with inconclusive lumbar MRI. Eur J Radiol 2020; 131:109249. [DOI: 10.1016/j.ejrad.2020.109249] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Revised: 08/08/2020] [Accepted: 08/17/2020] [Indexed: 11/19/2022]
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Diffusion Magnetic Resonance Imaging Predicts Peripheral Nerve Recovery in a Rat Sciatic Nerve Injury Model. Plast Reconstr Surg 2020; 145:949-956. [PMID: 32221212 DOI: 10.1097/prs.0000000000006638] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Nerve regeneration after an injury should occur in a timely fashion for function to be restored. Current methods cannot monitor regeneration prior to muscle reinnervation. Diffusion tensor imaging has been previously shown to provide quantitative indices after nerve recovery. The goal of this study was to validate the use of this technology following nerve injury via a series of rat sciatic nerve injury/repair studies. METHODS Sprague-Dawley rats were prospectively divided by procedure (sham, crush, or cut/repair) and time points (1, 2, 4, and 12 weeks after surgery). At the appropriate time point, each animal was euthanized and the sciatic nerve was harvested and fixed. Data were obtained using a 7-Tesla magnetic resonance imaging system. For validation, findings were compared to behavioral testing (foot fault asymmetry and sciatic function index) and cross-sectional axonal counting of toluidine blue-stained sections examined under light microscopy. RESULTS Sixty-three rats were divided into three treatment groups (sham, n = 21; crush, n = 23; and cut/repair, n = 19). Fractional anisotropy was able to differentiate between recovery following sham, crush, and cut/repair injuries as early as 2 weeks (p < 0.05), with more accurate differentiation thereafter. More importantly, the difference in anisotropy between distal and proximal regions recognized animals with successful and failed recoveries according to behavioral analysis, especially at 12 weeks. In addition, diffusion tension imaging-based tractography provided a visual representation of nerve continuity in all treatment groups. CONCLUSIONS Diffuse tensor imaging is an objective and noninvasive tool for monitoring nerve regeneration. Its use could facilitate earlier detection of failed repairs to potentially help improve outcomes.
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Holmes S, Barakat N, Bhasin M, Lopez N, Lebel A, Zurakowski D, Thomas B, Bhasin S, Silva K, Borra R, Burstein R, Simons L, Borsook D. Biological and behavioral markers of pain following nerve injury in humans. NEUROBIOLOGY OF PAIN (CAMBRIDGE, MASS.) 2020; 7:100038. [PMID: 31890990 PMCID: PMC6926375 DOI: 10.1016/j.ynpai.2019.100038] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 11/12/2019] [Accepted: 11/19/2019] [Indexed: 12/18/2022]
Abstract
The evolution of peripheral and central changes following a peripheral nerve injury imply the onset of afferent signals that affect the brain. Changes to inflammatory processes may contribute to peripheral and central alterations such as altered psychological state and are not well characterized in humans. We focused on four elements that change peripheral and central nervous systems following ankle injury in 24 adolescent patients and 12 age-sex matched controls. Findings include (a) Changes in tibial, fibular, and sciatic nerve divisions consistent with neurodegeneration; (b) Changes within the primary motor and somatosensory areas as well as higher order brain regions implicated in pain processing; (c) Increased expression of fear of pain and pain reporting; and (d) Significant changes in cytokine profiles relating to neuroinflammatory signaling pathways. Findings address how changes resulting from peripheral nerve injury may develop into chronic neuropathic pain through changes in the peripheral and central nervous system.
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Affiliation(s)
- S.A. Holmes
- Department of Anesthesiology, Critical Care & Pain Medicine, Boston Children’s Hospital, Boston, MA 02215, United States
- Department of Anesthesia, Harvard Medical School, Boston, MA 02115, United States
| | - N. Barakat
- Department of Anesthesiology, Critical Care & Pain Medicine, Boston Children’s Hospital, Boston, MA 02215, United States
- Department of Anesthesia, Harvard Medical School, Boston, MA 02115, United States
| | - M. Bhasin
- Bioinformatic and Systems Biology Center, Beth Israel Deaconess Medical Center, United States
- Department of Medicine, Harvard Medical School, United States
| | - N.I. Lopez
- Department of Anesthesiology, Critical Care & Pain Medicine, Boston Children’s Hospital, Boston, MA 02215, United States
| | - A. Lebel
- Department of Anesthesiology, Critical Care & Pain Medicine, Boston Children’s Hospital, Boston, MA 02215, United States
- Department of Anesthesia, Harvard Medical School, Boston, MA 02115, United States
| | - D. Zurakowski
- Department of Anesthesiology, Critical Care & Pain Medicine, Boston Children’s Hospital, Boston, MA 02215, United States
| | - B. Thomas
- Bioinformatic and Systems Biology Center, Beth Israel Deaconess Medical Center, United States
- Department of Medicine, Harvard Medical School, United States
| | - S. Bhasin
- Bioinformatic and Systems Biology Center, Beth Israel Deaconess Medical Center, United States
- Department of Medicine, Harvard Medical School, United States
| | - K.E. Silva
- Department of Anesthesiology, Critical Care & Pain Medicine, Boston Children’s Hospital, Boston, MA 02215, United States
| | - R. Borra
- Department of Radiology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713 GZ Groningen, Netherlands
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713 GZ Groningen, Netherlands
| | - R. Burstein
- Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center, United States
| | - L.E. Simons
- Department of Anesthesiology, Perioperative & Pain Medicine, Stanford University School of Medicine, Stanford, CA 94305, United States
| | - D. Borsook
- Department of Anesthesiology, Critical Care & Pain Medicine, Boston Children’s Hospital, Boston, MA 02215, United States
- Department of Anesthesia, Harvard Medical School, Boston, MA 02115, United States
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Feasibility of Diffusion Tensor and Morphologic Imaging of Peripheral Nerves at Ultra-High Field Strength. Invest Radiol 2019; 53:705-713. [PMID: 29979328 PMCID: PMC6221405 DOI: 10.1097/rli.0000000000000492] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Supplemental digital content is available in the text. Objectives The aim of this study was to describe the development of morphologic and diffusion tensor imaging sequences of peripheral nerves at 7 T, using carpal tunnel syndrome (CTS) as a model system of focal nerve injury. Materials and Methods Morphologic images were acquired at 7 T using a balanced steady-state free precession sequence. Diffusion tensor imaging was performed using single-shot echo-planar imaging and readout-segmented echo-planar imaging sequences. Different acquisition and postprocessing methods were compared to describe the optimal analysis pipeline. Magnetic resonance imaging parameters including cross-sectional areas, signal intensity, fractional anisotropy (FA), as well as mean, axial, and radial diffusivity were compared between patients with CTS (n = 8) and healthy controls (n = 6) using analyses of covariance corrected for age (significance set at P < 0.05). Pearson correlations with Bonferroni correction were used to determine association of magnetic resonance imaging parameters with clinical measures (significance set at P < 0.01). Results The 7 T acquisitions with high in-plane resolution (0.2 × 0.2mm) afforded detailed morphologic resolution of peripheral nerve fascicles. For diffusion tensor imaging, single-shot echo-planar imaging was more efficient than readout-segmented echo-planar imaging in terms of signal-to-noise ratio per unit scan time. Distortion artifacts were pronounced, but could be corrected during postprocessing. Registration of FA maps to the morphologic images was successful. The developed imaging and analysis pipeline identified lower median nerve FA (pisiform bone, 0.37 [SD 0.10]) and higher radial diffusivity (1.08 [0.20]) in patients with CTS compared with healthy controls (0.53 [0.06] and 0.78 [0.11], respectively, P < 0.047). Fractional anisotropy and radial diffusivity strongly correlated with patients' symptoms (r = −0.866 and 0.866, respectively, P = 0.005). Conclusions Our data demonstrate the feasibility of morphologic and diffusion peripheral nerve imaging at 7 T. Fractional anisotropy and radial diffusivity were found to be correlates of symptom severity.
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Assessment of the Effect of Autograft Orientation on Peripheral Nerve Regeneration Using Diffusion Tensor Imaging. Ann Plast Surg 2019; 80:384-390. [PMID: 29443831 DOI: 10.1097/sap.0000000000001357] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE Given no definite consensus on the accepted autograft orientation during peripheral nerve injury repair, we compare outcomes between reverse and normally oriented autografts using an advanced magnetic resonance imaging technique, diffusion tensor imaging. METHODS Thirty-six female Sprague-Dawley rats were divided into 3 groups: sham-left sciatic nerve isolation without injury, reverse autograft-10-mm cut left sciatic nerve segment reoriented 180° and used to coapt the proximal and distal stumps, or normally oriented autograft-10-mm cut nerve segment kept in its normal orientation for coaptation. Animals underwent sciatic functional index and foot fault behavior studies at 72 hours, and then weekly. At 6 weeks, axons proximal, within, and distal to the autograft were evaluated using diffusion tensor imaging and choline acetyltransferase motor staining for immunohistochemistry. Toluidine blue staining of 1-μm sections was used to assess axon count, density, and diameter. Bilateral gastrocnemius/soleus muscle weights were compared to obtain a net wet weight. Comparison of the groups was performed using Mann-Whiney U or Kruskal-Wallis H tests to determine significance. RESULTS Diffusion tensor imaging findings including fractional anisotropy, radial diffusivity, and axial diffusivity were similar between reverse and normally oriented autografts. Diffusion tensor imaging tractography demonstrated proximodistal nerve regeneration in both autograft groups. Motor axon counts proximal, within, and distal to the autografts were similar. Likewise, axon count, density, and diameter were similar between the autograft groups. Muscle net weight at 6 weeks and behavioral outcomes (sciatic functional index and foot fault) at any tested time point were also similar between reverse and normally oriented autografts. CONCLUSIONS Diffusion tensor imaging may be a useful assessment tool for peripheral nerve regeneration. Reversing nerve autograft polarity did not demonstrate to have an influence on functional or regenerative outcomes.
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Evaluation of select biocompatible markers for labelling peripheral nerves on 11.7 T MRI. J Neurosci Methods 2019; 315:6-13. [PMID: 30630001 DOI: 10.1016/j.jneumeth.2018.12.019] [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: 05/24/2018] [Revised: 12/27/2018] [Accepted: 12/29/2018] [Indexed: 11/21/2022]
Abstract
BACKGROUND Peripheral nerve injury is often followed by a highly variable recovery process with respect to both rapidity and efficacy. Identifying post-nerve injury phenomena is key to assessing the merit and timing of surgery as well as to tracking nerve recovery postoperatively. Diffusion Tensor Imaging (DTI) has been investigated in the clinical and research settings as a noninvasive technique to both assess and monitor each patient's unique case of peripheral nerve damage. NEW METHOD We identify a MRI-suitable marker for tracking the exact site of either nerve injury or coaptation following surgical repair to aid with DTI analysis. RESULTS Due to artefact and disruption of tractography, silver wire and microvascular clips were not suitable markers. AxoGuard®, 4-0 vicryl suture, and 10-0 polyamide suture, although detectable, did not produce a signal easily distinguished from post-surgical changes. Silicone was easily identifiable and stable in both the acute and delayed time points, exhibited negligible impact on DTI parameters, and possessed geometry to prevent nerve strangulation. COMPARISON WITH EXISTING METHOD Prior studies have not assessed the efficacy of other markers nor have they assessed silicone for potential artefact with DTI parameter analysis. Furthermore, this work demonstrates the reliability and compatibility of silicone in the delayed postoperative time period and includes its unique imaging appearance on high-resolution 11.7 MRI. CONCLUSION Semi-cylindrical silicone tubing can be used as a safe, reliable, and readily available radiological marker to visualize and monitor a region of interest on a rodent's peripheral nerve for aiding assessments with diffusion tensor imaging.
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Martín Noguerol T, Barousse R, Gómez Cabrera M, Socolovsky M, Bencardino JT, Luna A. Functional MR Neurography in Evaluation of Peripheral Nerve Trauma and Postsurgical Assessment. Radiographics 2019; 39:427-446. [DOI: 10.1148/rg.2019180112] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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21
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Cao J, He B, Wang S, Zhou Z, Gao F, Xiao L, Luo X, Wu C, Gong T, Chen W, Wang G. Diffusion Tensor Imaging of Tibial and Common Peroneal Nerves in Patients With Guillain-Barre Syndrome: A Feasibility Study. J Magn Reson Imaging 2018; 49:1356-1364. [PMID: 30252994 DOI: 10.1002/jmri.26324] [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: 06/05/2018] [Revised: 08/13/2018] [Accepted: 08/14/2018] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND The development of a noninvasive, objective, and accurate method to assess peripheral nerve disorders in Guillain-Barre syndrome (GBS) is of clinical significance. Diffusion tensor imaging (DTI) has been used to evaluate some peripheral nerve disorders. PURPOSE To investigate the feasibility of DTI in evaluating the peripheral nerve disorders in patients with GBS. STUDY TYPE Case control. SUBJECTS Twenty GBS patients and 16 healthy volunteers. FIELD STRENGTH/SEQUENCE 3.0T, T1 WI-SE, T2 WI-SPAIR, DTI; electrophysiology. ASSESSMENT MRI data were analyzed by two radiologists blindly and independently. Fractional anisotropy (FA), apparent diffusion coefficient (ADC), axial diffusion coefficient (AD), and radial diffusion coefficient (RD) values of tibial nerve (TN) and common peroneal nerve (CPN) were recorded. Motor nerve conduction velocity (MCV) and motor nerve conduction amplitude of TN and CPN were recorded. STATISTICAL TESTS Intraclass correlation coefficient (ICC), t-test, receiver-operating characteristic (ROC), and area under the curve (AUC) analysis, Pearson correlation coefficient. RESULTS The FA and AD values of TN and CPN in the GBS group were significantly lower and the ADC and RD values were higher than those in the controls (P <0.05). The AUC of the FA values (0.970 for TN and 0.927 for CPN) were higher than that of the ADC, AD, and RD values. FA and AD values were positively correlated and ADC, RD values were negatively correlated with MCV and motor nerve conduction amplitude, respectively (P <0.05). The correlations between FA value and electrophysiology parameters were the highest. DATA CONCLUSION DTI quantitative parameters could evaluate the disorders of peripheral nerves in patients with GBS. A moderate correlation was observed between DTI and electrophysiology parameters. LEVEL OF EVIDENCE 3 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;49:1356-1364.
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Affiliation(s)
- Jinfeng Cao
- Department of Radiology, Zibo Central Hospital, Zibo, Shandong, P.R. China
| | - Bing He
- Department of Radiology, Zibo Central Hospital, Zibo, Shandong, P.R. China
| | - Shanshan Wang
- Department of MR, Shandong Medical Imaging Research Institute, Shandong University, Jinan, Shandong, P.R. China
| | - Zhongmin Zhou
- Department of Nephrology, Zibo Central Hospital, Shandong, P.R. China
| | - Fei Gao
- Department of MR, Shandong Medical Imaging Research Institute, Shandong University, Jinan, Shandong, P.R. China
| | - Lianxiang Xiao
- Department of MR, Shandong Medical Imaging Research Institute, Shandong University, Jinan, Shandong, P.R. China
| | - Xin Luo
- Department of Radiology, Zibo Central Hospital, Zibo, Shandong, P.R. China
| | - Chao Wu
- Department of Radiology, Tianjin Medical University General Hospital, Tianjin, P.R. China
| | - Tao Gong
- Department of MR, Shandong Medical Imaging Research Institute, Shandong University, Jinan, Shandong, P.R. China
| | - Weibo Chen
- Philips Healthcare, Shanghai, P.R. China
| | - Guangbin Wang
- Department of MR, Shandong Medical Imaging Research Institute, Shandong University, Jinan, Shandong, P.R. China
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In vivo Diffusion Tensor Imaging, Diffusion Kurtosis Imaging, and Tractography of a Sciatic Nerve Injury Model in Rat at 9.4T. Sci Rep 2018; 8:12911. [PMID: 30150697 PMCID: PMC6110718 DOI: 10.1038/s41598-018-30961-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 07/24/2018] [Indexed: 11/08/2022] Open
Abstract
Peripheral nerve injuries result in severe loss of sensory and motor functions in the afflicted limb. There is a lack of standardised models to non-invasively study degeneration, regeneration, and normalisation of neuronal microstructure in peripheral nerves. This study aimed to develop a non-invasive evaluation of peripheral nerve injuries, using diffusion tensor imaging (DTI), diffusion kurtosis imaging (DKI), and tractography on a rat model of sciatic nerve injury. 10 female Sprague Dawley rats were exposed to sciatic nerve neurotmesis and studied using a 9.4 T magnet, by performing DTI and DKI of the sciatic nerve before and 4 weeks after injury. The distal nerve stump showed a decrease in fractional anisotropy (FA), mean kurtosis (MK), axonal water fraction (AWF), and radial and axonal kurtosis (RK, AK) after injury. The proximal stump showed a significant decrease in axial diffusivity (AD) and increase of MK and AK as compared with the uninjured nerve. Both mean diffusivity (MD) and radial diffusivity (RD) increased in the distal stump after injury. Tractography visualised the sciatic nerve and the site of injury, as well as local variations of the diffusion parameters following injury. In summary, the described method detects changes both proximal and distal to the nerve injury.
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Evaluation of two collagen conduits and autograft in rabbit sciatic nerve regeneration with quantitative magnetic resonance DTI, electrophysiology, and histology. Eur Radiol Exp 2018; 2:19. [PMID: 30148252 PMCID: PMC6091702 DOI: 10.1186/s41747-018-0049-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 05/24/2018] [Indexed: 12/18/2022] Open
Abstract
Background We compared different surgical techniques for nerve regeneration in a rabbit sciatic nerve gap model using magnetic resonance diffusion tensor imaging (DTI), electrophysiology, limb function, and histology. Methods A total of 24 male New Zealand white rabbits were randomized into three groups: autograft (n = 8), hollow conduit (n = 8), and collagen-filled conduit (n = 8). A 10-mm segment of the rabbit proximal sciatic nerve was cut, and autograft or collagen conduit was used to bridge the gap. DTI on a 3-T system was performed preoperatively and 13 weeks after surgery using the contralateral, nonoperated nerve as a control. Results Overall, autograft performed better compared with both conduit groups. Differences in axonal diameter were significant (autograft > hollow conduit > collagen-filled conduit) at 13 weeks (autograft vs. hollow conduit, p = 0.001, and hollow conduit vs. collagen-filled conduit, p < 0.001). Significant group differences were found for axial diffusivity but not for any of the other DTI metrics (autograft > hollow conduit > collagen-filled conduit) (autograft vs. hollow conduit, p = 0.001 and hollow conduit vs. collagen-filled conduit, p = 0.021). As compared with hollow conduit (autograft > collagen-filled conduit > hollow conduit), collagen-filled conduit animals demonstrated a nonsignificant increased maximum tetanic force. Conclusions Autograft-treated rabbits demonstrated improved sciatic nerve regeneration compared with collagen-filled and hollow conduits as assessed by histologic, functional, and DTI parameters at 13 weeks.
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Evaluation of Reproducibility of Diffusion Tensor Imaging in the Brachial Plexus at 3.0 T. Invest Radiol 2018; 52:482-487. [PMID: 28291025 DOI: 10.1097/rli.0000000000000363] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE The aim of this study was to evaluate the reproducibility of 3 T magnetic resonance imaging diffusion tensor imaging (DTI) of the brachial plexus in healthy subjects. METHODS Ten healthy volunteers were included, and morphological and DTI sequences of the nerve roots of the brachial plexus from C5 to T1 of both sides were repeatedly acquired on a 3 T magnetic resonance system (MAGNETOM Skyra; Siemens Healthcare, Erlangen, Germany). A prototype diffusion-weighted single-shot echo-planar imaging sequence-enabling slice-specific shim adjustments was performed with b-values of 0 and 800 s/mm in 30 gradient directions, resulting in an acquisition time of about 6 minutes each in axial orientation. Between scans, subjects were moved and repositioned in the scanner, coils were reinserted, and new localizers were acquired. Image analysis was performed using MITK Diffusion software toolkit. Two independent readers performed diffusion data postprocessing, and regions of interest (ROIs) were set on the proximal postganglionic trunk at each spinal level, bilaterally to obtain values for fractional anisotropy (FA) and mean diffusivity (MD). Interreader and intrareader agreement as well as test-retest reproducibility of DTI metrics were assessed. RESULTS Intraclass correlation coefficients (ICCs) for interreader and intrareader agreement did not differ significantly between measurements for FA and MD. In particular, ICCs for interreader agreement of FA ranged from 0.741 to 0.961 and that of MD ranged from 0.802 to 0.998, and ICCs for intrareader agreement of FA ranged from 0.759 to 0.949 and that of MD ranged from 0.796 to 0.998. The test-retest reproducibility of DTI metrics showed an overall moderate to strong correlation (r > 0.707), with few minor exceptions, for both FA and MD values. CONCLUSIONS Diffusion tensor imaging metrics in the brachial plexus are reproducible. Future applications of DTI for a possible clinical use should be further investigated.
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Wu W, Niu Y, Kong X, Liu D, Long X, Shu S, Su X, Wang B, Liu X, Ma Y, Wang L. Application of diffusion tensor imaging in quantitatively monitoring chronic constriction injury of rabbit sciatic nerves: correlation with histological and functional changes. Br J Radiol 2017; 91:20170414. [PMID: 29166135 DOI: 10.1259/bjr.20170414] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
OBJECTIVE To investigate the potential of diffusion tensor imaging (DTI) in quantitatively monitoring chronic constriction injuri (CCI) of sciatic nerves and to analyse the association of DTI parameters with nerve histology and limb function. METHODS CCI was created on sciatic nerves in the right hind legs of 20 rabbits with the left as control. DTI parameters-fractional anisotropy (FA), apparent diffusion coefficient (ADC), axial diffusivity (AD) and radial diffusivity (RD)-and limb function were longitudinally evaluated. Pathology analysis was performed on day 3 (d3), week 1 (w1), 2, 4, 6, 8 and 10. RESULTS FA of the constricted nerves decreased on d3 (0.316 ± 0.044) and increased from w1 to w10 (0.331 ± 0.018, 0.354 ± 0.044, 0.375 ± 0.015, 0.394 ± 0.020, 0.42 ± 0.03 and 0.464 ± 0.039). ADC increased on d3 until w2 (1.502 ± 0.126, 1.462 ± 0.058 and 1.473 ± 0.124 × 10-3 mm2 s-1) and decreased to normal from w4 to w10 (1.356 ± 0.129, 1.375 ± 0.107, 1.290 ± 0.064 and 1.298 ± 0.026 × 10-3 mm2 s-1). AD decreased and stayed low from d3 to w10 (2.042 ± 0.160, 2.005 ± 0.095, 2.057 ± 0.124, 1.952 ± 0.213, 1.988 ± 0.180, 1.947 ± 0.106 and 2.097 ± 0.114). RD increased on d3 (1.233 ± 0.152) and declined from w1 to w10 (1.19 ± 0.06, 1.181 ± 0.14, 1.071 ± 0.102, 1.068 ± 0.084, 0.961 ± 0.063 and 0.923 ± 0.058). FA, ADC and RD correlated significantly with limb functional scores (all Ps < 0.0001) and their changes were associated with histological changes. CONCLUSION FA, ADC and RD are promising to monitor CCI. AD may be a stable indicator for injury. Histological changes, oedema, axon loss and demyelination, and fibrosis, accompanied the changes of these parameters. Advances in knowledge: DTI parameters can detect and monitor acute and chronic changes after nerve compression.
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Affiliation(s)
- Wenjun Wu
- 1 Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology , Union Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , China
| | - Yanfeng Niu
- 2 Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology , Union Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , China
| | - Xiangquan Kong
- 1 Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology , Union Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , China
| | - Dingxi Liu
- 1 Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology , Union Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , China
| | - Xi Long
- 1 Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology , Union Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , China
| | - Shenglei Shu
- 1 Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology , Union Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , China
| | - Xiaoyun Su
- 1 Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology , Union Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , China
| | - Bing Wang
- 1 Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology , Union Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , China
| | - Xiaoming Liu
- 1 Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology , Union Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , China
| | - Yamei Ma
- 1 Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology , Union Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , China
| | - Lixia Wang
- 1 Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology , Union Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , China
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Wako Y, Nakamura J, Eguchi Y, Hagiwara S, Miura M, Kawarai Y, Sugano M, Nawata K, Yoshino K, Toguchi Y, Masuda Y, Matsumoto K, Suzuki T, Orita S, Ohtori S. Diffusion tensor imaging and tractography of the sciatic and femoral nerves in healthy volunteers at 3T. J Orthop Surg Res 2017; 12:184. [PMID: 29187253 PMCID: PMC5707804 DOI: 10.1186/s13018-017-0690-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 11/19/2017] [Indexed: 11/10/2022] Open
Abstract
Background The aim was to clarify the normal fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of the sciatic and femoral nerves at the level of the hip joint and to visualize the neural tracts with diffusion tensor imaging (DTI). Methods Twenty-four healthy volunteers (12 men and 12 women, age 20–29 years) underwent DTI for visualization with tractography and quantification of FA and ADC values on a 3 Tesla MRI (b value = 800 s/mm2, motion probing gradient, 11 directions, time to repeat/echo time = 9000/72.6 ms, axial slice orientation, slice thickness = 3.0 mm with no inter-slice gap, field of view = 320 × 320 mm, 96 × 192 matrix, 75 slices, number of acquisitions = 4). Regions of interest in the sciatic nerve were defined at the femoral head, the S1 root, and the midpoint levels. The femoral nerve was evaluated at 3–4 cm proximal to the femoral head level. Results The tractography of the sciatic and femoral nerves were visualized in all participants. The mean FA values of the sciatic nerve were increased distally from the S1 root level, through the midpoint, and to the femoral head level (0.314, 0.446, 0.567, p = 0.001, respectively). The mean FA values of the femoral nerve were 0.565. The mean ADC values of the sciatic nerves were significantly lower in the S1 root level than in the midpoint and the femoral head level (1.481, 1.602, 1.591 × 10−3 × 10−3 mm2/s, p = 0.001, respectively). The ADC values of the femoral nerve were 1.439 × 10−3 mm2/s. FA and ADC values showed moderate to substantial inter- and intra-observer reliability without significant differences in gender or laterality. Conclusion Visualization and quantification of the sciatic and femoral nerves simultaneously around the hip joint were achieved in healthy young volunteers with DTI. Clinical application of DTI is expected to contribute to hip pain research.
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Affiliation(s)
- Yasushi Wako
- Department of Orthopedic Surgery, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba city, Chiba, 260-8677, Japan.
| | - Junichi Nakamura
- Department of Orthopedic Surgery, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba city, Chiba, 260-8677, Japan
| | - Yawara Eguchi
- Department of Orthopedic Surgery, National Hospital Organization Shimoshizu National Hospital, 934-5, Shikawatashi, Yotsukaido city, Chiba, 284-0003, Japan
| | - Shigeo Hagiwara
- Department of Orthopedic Surgery, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba city, Chiba, 260-8677, Japan
| | - Michiaki Miura
- Department of Orthopedic Surgery, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba city, Chiba, 260-8677, Japan
| | - Yuya Kawarai
- Department of Orthopedic Surgery, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba city, Chiba, 260-8677, Japan
| | - Masahiko Sugano
- Department of Orthopedic Surgery, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba city, Chiba, 260-8677, Japan
| | - Kento Nawata
- Department of Orthopedic Surgery, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba city, Chiba, 260-8677, Japan
| | - Kensuke Yoshino
- Department of Orthopedic Surgery, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba city, Chiba, 260-8677, Japan
| | - Yasunari Toguchi
- Department of Orthopedic Surgery, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba city, Chiba, 260-8677, Japan
| | - Yoshitada Masuda
- Department of Radiology, Chiba University Hospital, 1-8-1 Inohana, Chuo-ku, Chiba city, Chiba, 260-8677, Japan
| | - Koji Matsumoto
- Department of Radiology, Chiba University Hospital, 1-8-1 Inohana, Chuo-ku, Chiba city, Chiba, 260-8677, Japan
| | - Takane Suzuki
- Department of Bioenvironmental Medicine, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba city, Chiba, 260-8677, Japan
| | - Sumihisa Orita
- Department of Orthopedic Surgery, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba city, Chiba, 260-8677, Japan
| | - Seiji Ohtori
- Department of Orthopedic Surgery, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba city, Chiba, 260-8677, Japan
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Hill BJ, Padgett KR, Kalra V, Marcillo A, Bowen B, Pattany P, Dietrich D, Quencer R. Gadolinium DTPA Enhancement Characteristics of the Rat Sciatic Nerve after Crush Injury at 4.7T. AJNR Am J Neuroradiol 2017; 39:177-183. [PMID: 29097415 DOI: 10.3174/ajnr.a5437] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 08/24/2017] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Traumatic peripheral nerve injury is common and results in loss of function and/or neuropathic pain. MR neurography is a well-established technique for evaluating peripheral nerve anatomy and pathology. However, the Gd-DTPA enhancement characteristics of acutely injured peripheral nerves have not been fully examined. This study was performed to determine whether acutely crushed rat sciatic nerves demonstrate Gd-DTPA enhancement and, if so, to evaluate whether enhancement is affected by crush severity. MATERIALS AND METHODS In 26 rats, the sciatic nerve was crushed with either surgical forceps (6- to 20-N compressive force) or a microvascular/microaneurysm clip (0.1-0.6 N). Animals were longitudinally imaged at 4.7T for up to 30 days after injury. T1WI, T2WI, and T1WI with Gd-DTPA were performed. RESULTS Forceps crush injury caused robust enhancement between days 3 and 21, while clip crush injury resulted in minimal-to-no enhancement. Enhancement after forceps injury peaked at 7 days and was seen a few millimeters proximal to, in the region of, and several centimeters distal to the site of crush injury. Enhancement after forceps injury was statistically significant compared with clip injury between days 3 and 7 (P < .04). CONCLUSIONS Gd-DTPA enhancement of peripheral nerves may only occur above a certain crush-severity threshold. This phenomenon may explain the intermittent observation of Gd-DTPA enhancement of peripheral nerves after traumatic injury. The observation of enhancement may be useful in judging the severity of injury after nerve trauma.
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Affiliation(s)
- B J Hill
- From the Departments of Radiology (B.J.H., K.R.P., B.B., P.P., R.Q.)
| | - K R Padgett
- From the Departments of Radiology (B.J.H., K.R.P., B.B., P.P., R.Q.) .,Radiation Oncology (K.R.P.).,Biomedical Engineering (K.R.P.)
| | - V Kalra
- Miller School of Medicine (V.K.), University of Miami, Miami, Florida
| | - A Marcillo
- Miami Project to Cure Paralysis (A.M., D.D.)
| | - B Bowen
- From the Departments of Radiology (B.J.H., K.R.P., B.B., P.P., R.Q.)
| | - P Pattany
- From the Departments of Radiology (B.J.H., K.R.P., B.B., P.P., R.Q.)
| | - D Dietrich
- Miami Project to Cure Paralysis (A.M., D.D.)
| | - R Quencer
- From the Departments of Radiology (B.J.H., K.R.P., B.B., P.P., R.Q.)
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Piriformis muscle syndrome with assessment of sciatic nerve using diffusion tensor imaging and tractography: a case report. Skeletal Radiol 2017; 46:1399-1404. [PMID: 28616638 DOI: 10.1007/s00256-017-2690-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 05/25/2017] [Accepted: 05/30/2017] [Indexed: 02/02/2023]
Abstract
Piriformis muscle syndrome (PMS) is difficult to diagnose by objective evaluation of sciatic nerve injury. Here we report a case of PMS diagnosed by diffusion tensor imaging (DTI) and tractography of the sciatic nerve, which can assess and visualize the extent of nerve injury. The patient was a 53-year-old man with a 2-year history of continuous pain and numbness in the left leg. His symptoms worsened when sitting. Physical examination, including sensorimotor neurologic tests, the deep tendon reflex test, and the straight leg raise test, revealed no specific findings. The hip flexion adduction and internal rotation test and resisted contraction maneuvers for the piriformis muscle were positive. There were no abnormal findings on magnetic resonance imaging (MRI) of the lumbar spine. The transverse diameter of piriformis muscle was slightly thicker in affected side on MRI of the pelvis. A single DTI sequence was performed during MRI of the pelvis. Fractional anisotropy (FA) and the apparent diffusion coefficient (ADC) of the sciatic nerve were quantified at three levels using the fiber-tracking method. FA values were significantly lower and ADC values were significantly higher distal to the piriformis muscle. We performed endoscopic-assisted resection of the piriformis tendon. Intraoperatively, the motor-evoked potentials in the left gastrocnemius were improved by resection of the piriformis tendon. The patient's symptoms improved immediately after surgery. There was no significant difference in FA or ADC at any level between the affected side and the unaffected side 3 months postoperatively. MRI-DTI may aid the diagnosis of PMS.
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Zhang J, Zhang F, Xiao F, Xiong Z, Liu D, Hua T, Indima N, Tang G. Quantitative Evaluation of the Compressed L5 and S1 Nerve Roots in Unilateral Lumbar Disc Herniation by Using Diffusion Tensor Imaging. Clin Neuroradiol 2017; 28:529-537. [DOI: 10.1007/s00062-017-0621-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Accepted: 08/03/2017] [Indexed: 02/06/2023]
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Martín Noguerol T, Barousse R, Socolovsky M, Luna A. Quantitative magnetic resonance (MR) neurography for evaluation of peripheral nerves and plexus injuries. Quant Imaging Med Surg 2017; 7:398-421. [PMID: 28932698 DOI: 10.21037/qims.2017.08.01] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Traumatic conditions of peripheral nerves and plexus have been classically evaluated by morphological imaging techniques and electrophysiological tests. New magnetic resonance imaging (MRI) studies based on 3D fat-suppressed techniques are providing high accuracy for peripheral nerve injury evaluation from a qualitative point of view. However, these techniques do not provide quantitative information. Diffusion weighted imaging (DWI) and diffusion tensor imaging (DTI) are functional MRI techniques that are able to evaluate and quantify the movement of water molecules within different biological structures. These techniques have been successfully applied in other anatomical areas, especially in the assessment of central nervous system, and now are being imported, with promising results for peripheral nerve and plexus evaluation. DWI and DTI allow performing a qualitative and quantitative peripheral nerve analysis, providing valuable pathophysiological information about functional integrity of these structures. In the field of trauma and peripheral nerve or plexus injury, several derived parameters from DWI and DTI studies such as apparent diffusion coefficient (ADC) or fractional anisotropy (FA) among others, can be used as potential biomarkers of neural damage providing information about fiber organization, axonal flow or myelin integrity. A proper knowledge of physical basis of these techniques and their limitations is important for an optimal interpretation of the imaging findings and derived data. In this paper, a comprehensive review of the potential applications of DWI and DTI neurographic studies is performed with a focus on traumatic conditions, including main nerve entrapment syndromes in both peripheral nerves and brachial or lumbar plexus.
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Affiliation(s)
| | - Rafael Barousse
- Peripheral Nerve and Plexus Department, Centro Rossi, Buenos Aires, Argentina
| | - Mariano Socolovsky
- Peripheral Nerve and Plexus Surgery Unit, Department of Neurosurgery, University of Buenos Aires School of Medicine, Buenos Aires, Argentina
| | - Antonio Luna
- MRI Unit, Neuroradiology Section, Clínica Las Nieves, SERCOSA, Health Time, Jaén, Spain.,Department of Radiology, University Hospitals of Cleveland, Case Western Reserve University, Cleveland, OH, USA
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Zheng CS, Zhang X, Chen YY, Zhang F, Duan XH, Chen MW, Lu LJ, Shen J. Assessment of the synergic effect of immunomodulation on nerve repair using multiparametric magnetic resonance imaging. Muscle Nerve 2017; 57:E38-E45. [PMID: 28445921 DOI: 10.1002/mus.25674] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 04/05/2017] [Accepted: 04/23/2017] [Indexed: 01/15/2023]
Abstract
INTRODUCTION The immune system plays a pivotal role in nerve injury. The aim of this study was to determine the role of multiparametric magnetic resonance imaging (MRI) in evaluation of the synergic effect of immunomodulation on nerve regeneration in neurotmesis. METHODS Rats with sciatic nerve neurotmesis and surgical repair underwent serial multiparametric MR examinations over an 8-week period after subepineurial microinjection of lipopolysaccharide (LPS) and subsequent subcutaneous injection of FK506 or subepineurial microinjection of LPS or phosphate-buffered saline (PBS) alone. RESULTS Nerves treated with immunomodulation showed more prominent regeneration than those treated with LPS or PBS alone and more rapid restoration toward normal T2, fractional anisotropy (FA), and radial diffusivity (RD) values than nerves injected with LPS or PBS. DISCUSSION Nerves treated with immunomodulation exert synergic beneficial effects on nerve regeneration that can be predicted by T2 measurements and FA and RD values. Muscle Nerve 57: E38-E45, 2018.
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Affiliation(s)
- Chu-Shan Zheng
- Department of Radiology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, No. 107 Yanjiang Road West, Guangzhou, 510120, Guangdong, China
| | - Xiang Zhang
- Department of Radiology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, No. 107 Yanjiang Road West, Guangzhou, 510120, Guangdong, China
| | - Yue-Yao Chen
- Department of Radiology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, No. 107 Yanjiang Road West, Guangzhou, 510120, Guangdong, China
| | - Fang Zhang
- Department of Radiology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, No. 107 Yanjiang Road West, Guangzhou, 510120, Guangdong, China
| | - Xiao-Hui Duan
- Department of Radiology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, No. 107 Yanjiang Road West, Guangzhou, 510120, Guangdong, China
| | - Mei-Wei Chen
- Department of Radiology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, No. 107 Yanjiang Road West, Guangzhou, 510120, Guangdong, China
| | - Lie-Jing Lu
- Department of Radiology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, No. 107 Yanjiang Road West, Guangzhou, 510120, Guangdong, China
| | - Jun Shen
- Department of Radiology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, No. 107 Yanjiang Road West, Guangzhou, 510120, Guangdong, China
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Creze M, Zaitouna M, Krystel NT, Diallo D, Lebacle C, Bellin MF, Ducreux D, Benoit G, Bessede T. Functional and structural microanatomy of the fetal sciatic nerve. Muscle Nerve 2016; 56:787-796. [PMID: 28006841 DOI: 10.1002/mus.25531] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 12/08/2016] [Accepted: 12/19/2016] [Indexed: 12/15/2022]
Abstract
INTRODUCTION The ultrastructure of a nerve has implications for surgical nerve repair. The aim of our study was to characterize the fascicular versus fibrillar anatomy and the autonomic versus somatic nature of the fetal sciatic nerve (SN). METHODS Immunohistochemistry for vesicular acetylcholine transporter, tyrosine hydroxylase, and peripheral myelin protein 22 was performed to identify cholinergic, adrenergic, and somatic axons, respectively, in the human fetal SN. Two-dimensional (2D) analysis and 3D reconstructions were performed. RESULTS The fetal SN is composed of one-third stromal tissue and two-thirds neural tissue. Autonomic fibers are predominant over somatic fibers within the neural tissue. The distribution of somatic fibers is initially random, but then become topographically organized after intra- and interfascicular rearrangements have occurred within the nerve. CONCLUSIONS The fetal model presents limitations but enables illustration of the nature of the nerve fibers and the 3D fascicular anatomy of the SN. Muscle Nerve 56: 787-796, 2017.
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Affiliation(s)
- Maud Creze
- U1195, INSERM, University of Paris Sud, France
| | | | | | | | | | - Marie-France Bellin
- Department of Radiology, University of Paris Sud, University Hospital Bicêtre, AP-HP, France
| | - Denis Ducreux
- Department of Neuroradiology, University of Paris Sud, University Hospital Bicêtre, AP-HP, France
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Wang Y, Tang Q, Zhu L, Huang R, Huang L, Koleini M, Zou D. Effects of Treatment of Treadmill Combined with Electro-Acupuncture on Tibia Bone Mass and Substance PExpression of Rabbits with Sciatic Nerve Injury. PLoS One 2016; 11:e0164652. [PMID: 27880769 PMCID: PMC5120789 DOI: 10.1371/journal.pone.0164652] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 09/28/2016] [Indexed: 12/31/2022] Open
Abstract
The peripheral nervous system may play an important role in normal bone maintenance and remodeling. Substance P (SP) is a neuropeptide associated with bone loss and formation that may mediate the effects of the nervous system. The purpose of this study is to determine if treadmill running combined with electro-acupuncture at Jiaji acupoints (Jiaji-EA) affects tibial bone mass and SP expression in rabbits with sciatic nerve injury. Twenty-four juvenile male New Zealand white rabbits were randomly assigned to one of 4 groups: sham injury control (sham), sciatic never crush control (SNCr), treadmill running (treadmill), and Jiaji-EA combined with treadmill running (ET group). The SNCr, treadmill, and ET groups all had an induced sciatic never crush injury of approximately 2mm. Control groups received no intervention; the treadmill and ET groups were trained by treadmill; the ET group also received Jiaji-EA. After the 4 weeks of treatment, toe-spreading index (TSI), BMD, bone strength, and SP expression in the tibia were significantly lower in the nerve injury groups (SNCr, treadmill, and ET) compared to the sham groups (p<0.05). Treatment (treadmill and ET groups) increased all measures compared to the SNCr group (p<0.05). Further, TSI, BMD, bone strength, and SP expression in the ET group were higher than the treadmill group (p<0.05). Our results indicate that treadmill therapy combined with electro-acupuncture at Jiaji acupoints prevents bone loss in rabbit tibias after sciatic nerve injury. This may occur in two ways: indirectly in association with axon regeneration and directly via loading on the bone mediated through increased SP expression. This study provides important evidence for the clinical treatment of bone loss after peripheral nerve injury.
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Affiliation(s)
- Yan Wang
- The 2nd affiliated hospital of Heilongjiang University of Chinese Medicine, Harbin, China
- Heilongjiang University of Chinese Medicine, Harbin, China
- * E-mail:
| | - Qiang Tang
- The 2nd affiliated hospital of Heilongjiang University of Chinese Medicine, Harbin, China
- Heilongjiang University of Chinese Medicine, Harbin, China
| | - Luwen Zhu
- The 2nd affiliated hospital of Heilongjiang University of Chinese Medicine, Harbin, China
- Heilongjiang University of Chinese Medicine, Harbin, China
| | - Ruyi Huang
- Heilongjiang University of Chinese Medicine, Harbin, China
| | - Lei Huang
- Heilongjiang University of Chinese Medicine, Harbin, China
| | - Melanie Koleini
- HRPO, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Dequan Zou
- Program in Physical Therapy, Washington University School of Medicine, St. Louis, Missouri, United States of America
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Chen YY, Zhang X, Lin XF, Zhang F, Duan XH, Zheng CS, Chen MW, Wang DY, Zeng WK, Shen J. DTI metrics can be used as biomarkers to determine the therapeutic effect of stem cells in acute peripheral nerve injury. J Magn Reson Imaging 2016; 45:855-862. [PMID: 27448779 DOI: 10.1002/jmri.25395] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 07/05/2016] [Indexed: 12/20/2022] Open
Abstract
PURPOSE To determine the role of diffusion tensor imaging (DTI) metrics as biomarkers for the therapeutic effects of mesenchymal stem cells (MSCs) in acute peripheral nerve injury. MATERIALS AND METHODS Forty-four adult rats received subepineurial microinjection of MSCs (n = 22) or phosphate buffered saline (PBS, n = 22) 1 week after the sciatic nerve trunk crush injury. Sequential fat-suppressed T2-weighted imaging, T2 measurement, DTI and sciatic nerve functional assessment were performed at a 3.0 Tesla MR unit over an 8-week follow-up, with histological assessments performed at regular intervals. The sciatic nerve function index, T2 value, and DTI metrics, including fractional anisotropy (FA), axial diffusivity, radial diffusivity (RD), and mean diffusivity values of the distal stumps of crushed nerves were measured and compared between the two groups. RESULTS Nerves treated with MSCs showed better functional recovery and exhibited more pronounced nerve regeneration compared with nerves treated with PBS. T2 values in nerves treated with MSCs or PBS showed a similar change pattern (P = 0.174), while FA and RD values in nerves treated with MSCs showed more rapid return (one week earlier) to baseline level than nerves treated with PBS (P = 0.045; 0.035). Nerves treated with MSCs had higher FA and lower RD values than nerves treated with PBS during the period from 2 to 3 weeks after surgery (P ≤ 0.0001, 0.004; P = 0.004, 0.006). CONCLUSION FA and RD values derived from DTI might be used as sensitive biomarkers for detecting the therapeutic effect of stem cells in acute peripheral nerve crush injuries. LEVEL OF EVIDENCE 2 J. Magn. Reson. Imaging 2017;45:855-862.
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Affiliation(s)
- Yue-Yao Chen
- Department of Radiology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Xiang Zhang
- Department of Radiology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Xiao-Feng Lin
- Department of Radiology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Fang Zhang
- Department of Radiology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Xiao-Hui Duan
- Department of Radiology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Chu-Shan Zheng
- Department of Radiology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Mei-Wei Chen
- Department of Radiology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Dong-Ye Wang
- Department of Radiology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Wei-Ke Zeng
- Department of Radiology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Jun Shen
- Department of Radiology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong, China
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35
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Gallagher TA, Simon NG, Kliot M. Diffusion tensor imaging to visualize axons in the setting of nerve injury and recovery. Neurosurg Focus 2015; 39:E10. [DOI: 10.3171/2015.6.focus15211] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Successful management of peripheral nerve trauma relies on accurate localization of the injury and grading of the severity of nerve injury to determine whether surgical intervention is required. Existing techniques, such as electrodiagnostic studies and conventional imaging modalities, provide important information, but are limited by being unable to distinguish severe nerve lesions in continuity that will recover from those that will not. Diffusion tensor imaging (DTI) and tractography of peripheral nerves provide a novel technique to localize and grade nerve injury, by assessing the integrity of the nerve fibers across the site of nerve injury. Diffusion tensor imaging and tractography also hold promise as markers of early nerve regeneration, prior to clinical and electrodiagnostic evidence of recovery. In the present review, the techniques of peripheral nerve DTI and tractography are discussed with respect to peripheral nerve trauma, with illustrative cases demonstrating potential roles of these novel approaches.
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Affiliation(s)
- Thomas Anthony Gallagher
- Departments of 1Radiology and
- 2Neurosurgery, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Neil G. Simon
- 3Prince of Wales Clinical School, University of New South Wales, Sydney; and
- 4Department of Neurology, St. Vincent’s Hospital, Darlinghurst, New South Wales, Australia
| | - Michel Kliot
- 2Neurosurgery, Northwestern University Feinberg School of Medicine, Chicago, Illinois
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36
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Hopkins TM, Heilman AM, Liggett JA, LaSance K, Little KJ, Hom DB, Minteer DM, Marra KG, Pixley SK. Combining micro-computed tomography with histology to analyze biomedical implants for peripheral nerve repair. J Neurosci Methods 2015; 255:122-30. [PMID: 26300184 DOI: 10.1016/j.jneumeth.2015.08.016] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 07/16/2015] [Accepted: 08/12/2015] [Indexed: 12/22/2022]
Abstract
BACKGROUND Biomedical implants used in tissue engineering repairs, such as scaffolds to repair peripheral nerves, can be too large to examine completely with histological analyses. Micro-computed tomography (micro-CT) with contrast agents allows ex vivo visualization of entire biomaterial implants and their interactions with tissues, but contrast agents can interfere with histological analyses of the tissues or cause shrinkage or loss of antigenicity. NEW METHOD Soft tissue, ex vivo micro-CT imaging using Lugol's iodine was compatible with histology after using a rapid (48 h) method of removing iodine. RESULTS Adult normal and repaired rat sciatic nerves were infiltrated ex vivo with iodine, imaged with micro-CT and then the iodine was removed by incubating tissues in sodium thiosulfate. Subsequent paraffin sections of normal nerve tissues showed no differences in staining with hematoxylin and eosin or immunostaining with multiple antibodies. Iodine treatment and removal did not alter axonal diameter, nuclear size or relative area covered by immunostained axons (p>0.05). Combining imaging modalities allowed comparisons of macroscopic and microscopic features of nerve tissues regenerating through simple nerve conduits or nerve conduits containing a titanium wire for guidance. COMPARISON WITH EXISTING METHODS Quantification showed that treatment with iodine and sodium thiosulfate did not result in tissue shrinkage or loss of antigenicity. CONCLUSIONS Because this combination of treatments is rapid and does not alter tissue morphology, this expands the ex vivo methods available to examine the success of biomaterial implants used for tissue engineering repairs.
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Affiliation(s)
- Tracy M Hopkins
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, United States
| | - Alexander M Heilman
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, United States
| | - James A Liggett
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, United States
| | - Kathleen LaSance
- Vontz Core Imaging Lab (VCIL), University of Cincinnati College of Medicine, Cincinnati, United States
| | - Kevin J Little
- Division of Pediatric Orthopaedics, Cincinnati Children's Hospital Medical Center, Cincinnati, United States
| | - David B Hom
- Division of Facial Plastic & Reconstructive Surgery, Program Director for the Facial Paralysis Clinic, Department of Otolaryngology-Head and Neck Surgery, University of Cincinnati College of Medicine, Cincinnati, United States
| | - Danielle M Minteer
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, United States
| | - Kacey G Marra
- Departments of Plastic Surgery and Bioengineering, University of Pittsburgh, Pittsburgh, United States; Plastic Surgery Research Laboratory, Faculty, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, United States
| | - Sarah K Pixley
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, United States.
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37
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Geuna S. The sciatic nerve injury model in pre-clinical research. J Neurosci Methods 2015; 243:39-46. [PMID: 25629799 DOI: 10.1016/j.jneumeth.2015.01.021] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 01/15/2015] [Accepted: 01/16/2015] [Indexed: 12/15/2022]
Abstract
In the pre-clinical view, the study of peripheral nerve repair and regeneration still needs to be carried out in animal models due to the structural complexity of this organ which can be only partly simulated in vitro. The far most used experimental model is based on the injury of the sciatic nerve, the largest nerve trunk in mammals. In this paper, the potential application of the sciatic nerve injury model in pre-clinical research is critically reviewed. This paper is aimed at helping researchers in properly employing this in vivo model for the study of nerve repair and regeneration as well as interpreting the results in a clinical translation perspective.
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Affiliation(s)
- Stefano Geuna
- Neuroscience Institute of the Cavalieri Ottolenghi Foundation & Department of Clinical and Biological Sciences, University of Turin, Italy.
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