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Mobarak-Abadi M, Mahmoudi-Aznaveh A, Dehghani H, Zarei M, Vahdat S, Doyon J, Khatibi A. DeepRetroMoCo: deep neural network-based retrospective motion correction algorithm for spinal cord functional MRI. Front Psychiatry 2024; 15:1323109. [PMID: 39006826 PMCID: PMC11239515 DOI: 10.3389/fpsyt.2024.1323109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 05/21/2024] [Indexed: 07/16/2024] Open
Abstract
Background and purpose There are distinct challenges in the preprocessing of spinal cord fMRI data, particularly concerning the mitigation of voluntary or involuntary movement artifacts during image acquisition. Despite the notable progress in data processing techniques for movement detection and correction, applying motion correction algorithms developed for the brain cortex to the brainstem and spinal cord remains a challenging endeavor. Methods In this study, we employed a deep learning-based convolutional neural network (CNN) named DeepRetroMoCo, trained using an unsupervised learning algorithm. Our goal was to detect and rectify motion artifacts in axial T2*-weighted spinal cord data. The training dataset consisted of spinal cord fMRI data from 27 participants, comprising 135 runs for training and 81 runs for testing. Results To evaluate the efficacy of DeepRetroMoCo, we compared its performance against the sct_fmri_moco method implemented in the spinal cord toolbox. We assessed the motion-corrected images using two metrics: the average temporal signal-to-noise ratio (tSNR) and Delta Variation Signal (DVARS) for both raw and motion-corrected data. Notably, the average tSNR in the cervical cord was significantly higher when DeepRetroMoCo was utilized for motion correction, compared to the sct_fmri_moco method. Additionally, the average DVARS values were lower in images corrected by DeepRetroMoCo, indicating a superior reduction in motion artifacts. Moreover, DeepRetroMoCo exhibited a significantly shorter processing time compared to sct_fmri_moco. Conclusion Our findings strongly support the notion that DeepRetroMoCo represents a substantial improvement in motion correction procedures for fMRI data acquired from the cervical spinal cord. This novel deep learning-based approach showcases enhanced performance, offering a promising solution to address the challenges posed by motion artifacts in spinal cord fMRI data.
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Affiliation(s)
- Mahdi Mobarak-Abadi
- Institute of Medical Science and Technology, Shahid Beheshti University, Tehran, Iran
| | | | - Hamed Dehghani
- Neuro Imaging and Analysis Group (NIAG), Research Center for Molecular and Cellular Imaging (RCMCI), Tehran University of Medical Sciences, Tehran, Iran
| | - Mojtaba Zarei
- Institute of Medical Science and Technology, Shahid Beheshti University, Tehran, Iran
| | - Shahabeddin Vahdat
- Department of Applied Physiology and Kinesiology (DAPK), University of Florida, Gainesville, FL, United States
| | - Julien Doyon
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Ali Khatibi
- Centre of Precision Rehabilitation for Spinal Pain, School of Sports Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
- Centre for Human Brain Health, University of Birmingham, Birmingham, United Kingdom
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Abd-Elsayed A, Vardhan S, Aggarwal A, Vardhan M, Diwan SA. Mechanisms of Action of Dorsal Root Ganglion Stimulation. Int J Mol Sci 2024; 25:3591. [PMID: 38612402 PMCID: PMC11011701 DOI: 10.3390/ijms25073591] [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: 02/19/2024] [Revised: 03/12/2024] [Accepted: 03/19/2024] [Indexed: 04/14/2024] Open
Abstract
The dorsal root ganglion (DRG) serves as a pivotal site for managing chronic pain through dorsal root ganglion stimulation (DRG-S). In recent years, the DRG-S has emerged as an attractive modality in the armamentarium of neuromodulation therapy due to its accessibility and efficacy in alleviating chronic pain refractory to conventional treatments. Despite its therapeutic advantages, the precise mechanisms underlying DRG-S-induced analgesia remain elusive, attributed in part to the diverse sensory neuron population within the DRG and its modulation of both peripheral and central sensory processing pathways. Emerging evidence suggests that DRG-S may alleviate pain by several mechanisms, including the reduction of nociceptive signals at the T-junction of sensory neurons, modulation of pain gating pathways within the dorsal horn, and regulation of neuronal excitability within the DRG itself. However, elucidating the full extent of DRG-S mechanisms necessitates further exploration, particularly regarding its supraspinal effects and its interactions with cognitive and affective networks. Understanding these mechanisms is crucial for optimizing neurostimulation technologies and improving clinical outcomes of DRG-S for chronic pain management. This review provides a comprehensive overview of the DRG anatomy, mechanisms of action of the DRG-S, and its significance in neuromodulation therapy for chronic pain.
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Affiliation(s)
- Alaa Abd-Elsayed
- Department of Anesthesiology, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53792, USA
| | - Swarnima Vardhan
- Department of Internal Medicine, Yale New Haven Health, Bridgeport Hospital, Bridgeport, CT 06605, USA; (S.V.); (A.A.)
- Advanced Spine on Park Avenue, New York, NY 10461, USA;
| | - Abhinav Aggarwal
- Department of Internal Medicine, Yale New Haven Health, Bridgeport Hospital, Bridgeport, CT 06605, USA; (S.V.); (A.A.)
| | - Madhurima Vardhan
- Argonne Leadership Computing Facility, Argonne National Laboratory, Lemont, IL 60439, USA;
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Su PYP, Arle J, Poree L. Closing the loop and raising the bar: Automated control systems in neuromodulation. Pain Pract 2024; 24:177-185. [PMID: 37638532 DOI: 10.1111/papr.13290] [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: 04/20/2023] [Accepted: 08/04/2023] [Indexed: 08/29/2023]
Abstract
INTRODUCTION Neuromodulation has emerged as a promising therapy for the management of chronic pain, movement disorders, and other neurological conditions. Spinal cord stimulation (SCS) is a widely used form of neuromodulation that involves the delivery of electrical impulses to the spinal cord to modulate the transmission of pain signals to the brain. In recent years, there has been increasing interest in the use of automation systems to improve the efficacy and safety of SCS. This narrative review summarizes the status of Food and Drug Administration-approved autonomous neuromodulation devices including closed loop, feedforward, and feedback systems. The review discusses the advantages and disadvantages of each system and focuses specifically on the use of these systems for SCS. It is important for clinicians to understand the expanding role of automation in neuromodulation in order to select appropriate therapies founded on automation systems to the specific needs of the patient and the underlying condition. CONCLUSION The review also provides insights into the current state of the art in neuromodulation automation systems and discusses potential future directions for research in this field.
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Affiliation(s)
- Po-Yi Paul Su
- Department of Anesthesia, University of California San Francisco, San Francisco, California, USA
| | | | - Lawrence Poree
- Department of Anesthesia, University of California San Francisco, San Francisco, California, USA
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Pfender N, Rosner J, Zipser CM, Friedl S, Schubert M, Sutter R, Klarhoefer M, Spirig JM, Betz M, Freund P, Farshad M, Curt A, Hupp M. Increased cranio-caudal spinal cord oscillations are the cardinal pathophysiological change in degenerative cervical myelopathy. Front Neurol 2023; 14:1217526. [PMID: 38020663 PMCID: PMC10663304 DOI: 10.3389/fneur.2023.1217526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023] Open
Abstract
Introduction Degenerative cervical myelopathy (DCM) is the most common cause of non-traumatic incomplete spinal cord injury, but its pathophysiology is poorly understood. As spinal cord compression observed in standard MRI often fails to explain a patient's status, new diagnostic techniques to assess DCM are one of the research priorities. Minor cardiac-related cranio-caudal oscillations of the cervical spinal cord are observed by phase-contrast MRI (PC-MRI) in healthy controls (HCs), while they become pathologically increased in patients suffering from degenerative cervical myelopathy. Whether transversal oscillations (i.e., anterior-posterior and right-left) also change in DCM patients is not known. Methods We assessed spinal cord motion simultaneously in all three spatial directions (i.e., cranio-caudal, anterior-posterior, and right-left) using sagittal PC-MRI and compared physiological oscillations in 18 HCs to pathological changes in 72 DCM patients with spinal canal stenosis. The parameter of interest was the amplitude of the velocity signal (i.e., maximum positive to maximum negative peak) during the cardiac cycle. Results Most patients suffered from mild DCM (mJOA score 16 (14-18) points), and the majority (68.1%) presented with multisegmental stenosis. The spinal canal was considerably constricted in DCM patients in all segments compared to HCs. Under physiological conditions in HCs, the cervical spinal cord oscillates in the cranio-caudal and anterior-posterior directions, while right-left motion was marginal [e.g., segment C5 amplitudes: cranio-caudal: 0.40 (0.27-0.48) cm/s; anterior-posterior: 0.18 (0.16-0.29) cm/s; right-left: 0.10 (0.08-0.13) cm/s]. Compared to HCs, DCM patients presented with considerably increased cranio-caudal oscillations due to the cardinal pathophysiologic change in non-stenotic [e.g., segment C5 amplitudes: 0.79 (0.49-1.32) cm/s] and stenotic segments [.g., segment C5 amplitudes: 0.99 (0.69-1.42) cm/s]). In contrast, right-left [e.g., segment C5 amplitudes: non-stenotic segment: 0.20 (0.13-0.32) cm/s; stenotic segment: 0.11 (0.09-0.18) cm/s] and anterior-posterior oscillations [e.g., segment C5 amplitudes: non-stenotic segment: 0.26 (0.15-0.45) cm/s; stenotic segment: 0.11 (0.09-0.18) cm/s] remained on low magnitudes comparable to HCs. Conclusion Increased cranio-caudal oscillations of the cervical cord are the cardinal pathophysiologic change and can be quantified using PC-MRI in DCM patients. This study addresses spinal cord oscillations as a relevant biomarker reflecting dynamic mechanical cord stress in DCM patients, potentially contributing to a loss of function.
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Affiliation(s)
- Nikolai Pfender
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
- University Spine Center Zurich, Balgrist University Hospital, Zurich, Switzerland
| | - Jan Rosner
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
- Department of Neurology, University Hospital Bern, Inselspital, Bern, Switzerland
| | - Carl M. Zipser
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
- University Spine Center Zurich, Balgrist University Hospital, Zurich, Switzerland
| | - Susanne Friedl
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
- University Spine Center Zurich, Balgrist University Hospital, Zurich, Switzerland
| | - Martin Schubert
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
- University Spine Center Zurich, Balgrist University Hospital, Zurich, Switzerland
| | - Reto Sutter
- Radiology, Balgrist University Hospital, Zurich, Switzerland
| | | | - José M. Spirig
- University Spine Center Zurich, Balgrist University Hospital, Zurich, Switzerland
| | - Michael Betz
- University Spine Center Zurich, Balgrist University Hospital, Zurich, Switzerland
| | - Patrick Freund
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
| | - Mazda Farshad
- University Spine Center Zurich, Balgrist University Hospital, Zurich, Switzerland
| | - Armin Curt
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
- University Spine Center Zurich, Balgrist University Hospital, Zurich, Switzerland
| | - Markus Hupp
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
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Al-shaari H, J F, R M, CJ H. A systematic review of repeatability and reproducibility studies of diffusion tensor imaging of cervical spinal cord. Br J Radiol 2023; 96:20221019. [PMID: 37751162 PMCID: PMC10607424 DOI: 10.1259/bjr.20221019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 07/12/2023] [Accepted: 08/10/2023] [Indexed: 09/27/2023] Open
Abstract
OBJECTIVES Diffusion tensor imaging (DTI) techniques are being studied as a possible diagnostic and predictive tool for the evaluation of cervical spinal cord disease. This systematic review aims to evaluate the previous DTI studies that specifically investigated the repeatability and reproducibility of DTI in the cervical spinal cord. METHODS AND MATERIALS A search in the PubMed, Scopus, Web of Science and Ovid electronic databases was conducted for articles published between January 1990 and February 2022 that related to the repeatability and reproducibility of DTI in evaluating the cervical spinal cord using one of the following measurements: the intraclass correlation coefficient (ICC) and/or the coefficient of variation (CV), and/or Bland-Altman (BA) differences analysis methods. DTI studies that presented full statistical analysis of repeatability and/or reproducibility tests of the cervical spinal cord in peer-reviewed full-text publications published in journals were included. Articles that included at least one of the keywords within the titles or abstracts were identified. Additional full-text papers were found by searching the citations and reference lists of related articles. This review has followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidance. Risk of bias was evaluated with 13 criteria weighted toward methodological quality of reported studies using the QuADS assessment criteria. This assessment only included full-text articles written in English. RESULTS A total of 11 studies were included and assessed for different characteristics, including sample size,(3-34) re-test time interval (<1 h to >3 months), test-retest reproducibility scores and acquisition method. Six studies used ICC which ranged from poor (ICC<0.37) to excellent reproducibility (ICC 0.91-0.99). Four studies reported an overall CV lower than 40% for all DTI metrics. Three studies reported the Bland-Altman (BA) differences and reported a minimum percentage showing no strong differences between repeated measurements. Quantitative analysis was not undertaken due to heterogeneity of methods. Repeatability and reproducibility measures were generally found to be good. CONCLUSION This study revealed that the application of DTI and its related measures in a clinical setting in the assessment of cervical spinal cord changes is feasible and reproducible. However, cervical spinal cord DTI suffers from some existing limitations that prevent it from being routinely used in research and clinical settings. ADVANCES IN KNOWLEDGE DTI with its parametric maps provide broad evaluation of the tissue structure of axonal white matter and are being studied as a possible diagnostic and predictive tool for the assessment of cervical spinal cord (CSC) disease.
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Affiliation(s)
| | - Fulford J
- Medical Imaging Department, Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
| | - Meertens R
- Medical Imaging Department, Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
| | - Heales CJ
- Medical Imaging Department, Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
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Khan AF, Haynes G, Mohammadi E, Muhammad F, Hameed S, Smith ZA. Utility of MRI in Quantifying Tissue Injury in Cervical Spondylotic Myelopathy. J Clin Med 2023; 12:jcm12093337. [PMID: 37176777 PMCID: PMC10179707 DOI: 10.3390/jcm12093337] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 04/28/2023] [Accepted: 05/05/2023] [Indexed: 05/15/2023] Open
Abstract
Cervical spondylotic myelopathy (CSM) is a progressive disease that worsens over time if untreated. However, the rate of progression can vary among individuals and may be influenced by various factors, such as the age of the patients, underlying conditions, and the severity and location of the spinal cord compression. Early diagnosis and prompt treatment can help slow the progression of CSM and improve symptoms. There has been an increased use of magnetic resonance imaging (MRI) methods in diagnosing and managing CSM. MRI methods provide detailed images and quantitative structural and functional data of the cervical spinal cord and brain, allowing for an accurate evaluation of the extent and location of tissue injury. This review aims to provide an understanding of the use of MRI methods in interrogating functional and structural changes in the central nervous system in CSM. Further, we identified several challenges hindering the clinical utility of these neuroimaging methods.
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Affiliation(s)
- Ali Fahim Khan
- Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Grace Haynes
- Stephenson School of Biomedical Engineering, University of Oklahoma, Norman, OK 73019, USA
| | - Esmaeil Mohammadi
- Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Fauziyya Muhammad
- Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Sanaa Hameed
- Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Zachary A Smith
- Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
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Arai K, Itoi T, Akashi N, Miyabe M, Sugimoto K, Matsuda A, Maeta N, Kanda T, Kutara K. Variation in Diffusion Tensor Imaging Parameters in the Cervical and Thoracic Spinal Cord (C1-C5 and C6-T2) Segments of Normal Beagle Dogs. Vet Sci 2023; 10:vetsci10010031. [PMID: 36669032 PMCID: PMC9864464 DOI: 10.3390/vetsci10010031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 12/23/2022] [Accepted: 12/25/2022] [Indexed: 01/04/2023] Open
Abstract
This study aimed to determine the characteristics and reference values of each vertebra in the cervicothoracic region by performing diffusion tensor imaging (DTI) scans and analyzing DTI parameters in normal Beagle dogs. In five adult Beagles under anesthetic maintenance, DTI was performed using a 1.5-T magnetic resonance imaging (MRI) scanner. Axial DTI was performed using three overlapping slabs to cover the cervical and thoracic spinal cords. After post-processing, DTI parameters were calculated along the entire spinal cord. Among DTI parameters, fractional anisotropy, relative anisotropy, and axonal diffusivity significantly decreased in the caudal direction. However, the apparent diffusion coefficient, radial diffusivity, and mean diffusivity values were not significantly correlated with vertebral levels. We provide evidence for the existence of segment-dependent DTI parameters in the canine cervical spinal cord. Therefore, comparisons of DTI parameters between lesions at different vertebral levels should be avoided unless normative data are available. Furthermore, the DTI data obtained in this study may contribute to the development of a clinical reference for spinal cord evaluation in dogs using DTI parameters.
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Hoggarth MA, Wang MC, Hemmerling KJ, Vigotsky AD, Smith ZA, Parrish TB, Weber KA, Bright MG. Effects of variability in manually contoured spinal cord masks on fMRI co-registration and interpretation. Front Neurol 2022; 13:907581. [PMID: 36341092 PMCID: PMC9630922 DOI: 10.3389/fneur.2022.907581] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 09/26/2022] [Indexed: 02/01/2023] Open
Abstract
Functional magnetic resonance imaging (fMRI) of the human spinal cord (SC) is a unique non-invasive method for characterizing neurovascular responses to stimuli. Group-analysis of SC fMRI data involves co-registration of subject-level data to standard space, which requires manual masking of the cord and may result in bias of group-level SC fMRI results. To test this, we examined variability in SC masks drawn in fMRI data from 21 healthy participants from a completed study mapping responses to sensory stimuli of the C7 dermatome. Masks were drawn on temporal mean functional image by eight raters with varying levels of neuroimaging experience, and the rater from the original study acted as a reference. Spatial agreement between rater and reference masks was measured using the Dice Similarity Coefficient, and the influence of rater and dataset was examined using ANOVA. Each rater's masks were used to register functional data to the PAM50 template. Gray matter-white matter signal contrast of registered functional data was used to evaluate the spatial normalization accuracy across raters. Subject- and group-level analyses of activation during left- and right-sided sensory stimuli were performed for each rater's co-registered data. Agreement with the reference SC mask was associated with both rater (F(7, 140) = 32.12, P < 2 × 10-16, η2 = 0.29) and dataset (F(20, 140) = 20.58, P < 2 × 10-16, η2 = 0.53). Dataset variations may reflect image quality metrics: the ratio between the signal intensity of spinal cord voxels and surrounding cerebrospinal fluid was correlated with DSC results (p < 0.001). As predicted, variability in the manually-drawn masks influenced spatial normalization, and GM:WM contrast in the registered data showed significant effects of rater and dataset (rater: F(8, 160) = 23.57, P < 2 × 10-16, η2 = 0.24; dataset: F(20, 160) = 22.00, P < 2 × 10-16, η2 = 0.56). Registration differences propagated into subject-level activation maps which showed rater-dependent agreement with the reference. Although group-level activation maps differed between raters, no systematic bias was identified. Increasing consistency in manual contouring of spinal cord fMRI data improved co-registration and inter-rater agreement in activation mapping, however our results suggest that improvements in image acquisition and post-processing are also critical to address.
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Affiliation(s)
- Mark A. Hoggarth
- Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Max C. Wang
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL, United States
| | - Kimberly J. Hemmerling
- Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL, United States
| | - Andrew D. Vigotsky
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL, United States
- Department of Statistics, Weinberg College of Arts and Sciences, Northwestern University, Evanston, IL, United States
| | - Zachary A. Smith
- Department of Neurological Surgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Todd B. Parrish
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL, United States
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Kenneth A. Weber
- Systems Neuroscience and Pain Lab, Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University, Palo Alto, CA, United States
| | - Molly G. Bright
- Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL, United States
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The Neurostimulation Appropriateness Consensus Committee (NACC): Recommendations on Best Practices for Cervical Neurostimulation. Neuromodulation 2022; 25:35-52. [DOI: 10.1016/j.neurom.2021.10.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 08/31/2021] [Accepted: 09/07/2021] [Indexed: 11/19/2022]
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Pfender N, Rosner J, Zipser CM, Friedl S, Vallotton K, Sutter R, Klarhoefer M, Schubert M, Betz M, Spirig JM, Seif M, Hubli M, Freund P, Farshad M, Curt A, Hupp M. Comparison of axial and sagittal spinal cord motion measurements in degenerative cervical myelopathy. J Neuroimaging 2022; 32:1121-1133. [PMID: 35962464 PMCID: PMC9805009 DOI: 10.1111/jon.13035] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 07/27/2022] [Accepted: 07/27/2022] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND AND PURPOSE The timing of decision-making for a surgical intervention in patients with mild degenerative cervical myelopathy (DCM) is challenging. Spinal cord motion phase contrast MRI (PC-MRI) measurements can reveal the extent of dynamic mechanical strain on the spinal cord to potentially identify high-risk patients. This study aims to determine the comparability of axial and sagittal PC-MRI measurements of spinal cord motion with the prospect of improving the clinical workup. METHODS Sixty-four DCM patients underwent a PC-MRI scan assessing spinal cord motion. The agreement of axial and sagittal measurements was determined by means of intraclass correlation coefficients (ICCs) and Bland-Altman analyses. RESULTS The comparability of axial and sagittal PC-MRI measurements was good to excellent at all cervical levels (ICCs motion amplitude: .810-.940; p < .001). Significant differences between axial and sagittal amplitude values could be found at segments C3 and C4, while its magnitude was low (C3: 0.07 ± 0.19 cm/second; C4: -0.12 ± 0.30 cm/second). Bland-Altman analysis showed a good agreement between axial and sagittal PC-MRI scans (coefficients of repeatability: minimum -0.23 cm/second at C2; maximum -0.58 cm/second at C4). Subgroup analysis regarding anatomic conditions (stenotic vs. nonstenotic segments) and different velocity encoding (2 vs. 3 cm/second) showed comparable results. CONCLUSIONS This study demonstrates good comparability between axial and sagittal spinal cord motion measurements in DCM patients. To this end, axial and sagittal PC-MRI are both accurate and sensitive in detecting pathologic cord motion. Therefore, such measures could identify high-risk patients and improve clinical decision-making (ie, timing of decompression).
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Affiliation(s)
- Nikolai Pfender
- Spinal Cord Injury CenterBalgrist University HospitalUniversity of ZurichZurichSwitzerland
| | - Jan Rosner
- Spinal Cord Injury CenterBalgrist University HospitalUniversity of ZurichZurichSwitzerland,Department of NeurologyBern University HospitalInselspitalUniversity of BernBernSwitzerland
| | - Carl Moritz Zipser
- Spinal Cord Injury CenterBalgrist University HospitalUniversity of ZurichZurichSwitzerland
| | - Susanne Friedl
- Spinal Cord Injury CenterBalgrist University HospitalUniversity of ZurichZurichSwitzerland
| | - Kevin Vallotton
- Spinal Cord Injury CenterBalgrist University HospitalUniversity of ZurichZurichSwitzerland
| | - Reto Sutter
- RadiologyBalgrist University HospitalUniversity of ZurichZurichSwitzerland
| | | | - Martin Schubert
- Spinal Cord Injury CenterBalgrist University HospitalUniversity of ZurichZurichSwitzerland
| | - Michael Betz
- University Spine Centre ZurichBalgrist University HospitalUniversity of ZurichZurichSwitzerland
| | - José Miguel Spirig
- University Spine Centre ZurichBalgrist University HospitalUniversity of ZurichZurichSwitzerland
| | - Maryam Seif
- Spinal Cord Injury CenterBalgrist University HospitalUniversity of ZurichZurichSwitzerland,Department of NeurophysicsMax Planck Institute for Human Cognitive and Brain SciencesLeipzigGermany
| | - Michèle Hubli
- Spinal Cord Injury CenterBalgrist University HospitalUniversity of ZurichZurichSwitzerland
| | - Patrick Freund
- Spinal Cord Injury CenterBalgrist University HospitalUniversity of ZurichZurichSwitzerland
| | - Mazda Farshad
- University Spine Centre ZurichBalgrist University HospitalUniversity of ZurichZurichSwitzerland
| | - Armin Curt
- Spinal Cord Injury CenterBalgrist University HospitalUniversity of ZurichZurichSwitzerland,University Spine Centre ZurichBalgrist University HospitalUniversity of ZurichZurichSwitzerland
| | - Markus Hupp
- Spinal Cord Injury CenterBalgrist University HospitalUniversity of ZurichZurichSwitzerland
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Liu Y, Tang GK, Wang WH, Shi CG, Wang S, Yu L, Yu JM, Ye XJ. Morphology of Herniated Disc as a Predictor for Outcomes of Posterior Percutaneous Full-endoscopic Cervical Discectomy in Treating Cervical Spondylotic Radiculopathy. Orthop Surg 2021; 13:2335-2343. [PMID: 34755465 PMCID: PMC8654662 DOI: 10.1111/os.13134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 04/22/2021] [Accepted: 06/22/2021] [Indexed: 11/28/2022] Open
Abstract
Objective To quantitively characterize the morphology of cervical disc herniation (CDH) causing cervical spondylotic radiculopathy (CSR) and investigate whether the morphological features of CDH are associated with clinical outcomes in CSR patients treated by posterior percutaneous full‐endoscopic cervical discectomy (PPECD). Methods This is a single‐center retrospective study. Eighty‐seven PPECD‐treated patients meeting the inclusion criteria were included between May 2017 and May 2019. Based on preoperative T2‐weighted magnetic resonance imaging (MRI), we designed and measured six morphological parameters of CDH for all patients to reflect its relative position to cervical spinal cord and protruding degree: DC‐SC distance from the center of disc (DC) and the center of spinal cord (SC); DC‐DP distance from the center of cervical disc (DC) to the peak of herniation (DP); internal diameter of the disc; axial length of CDH; central angle of CDH formed by central axes of CDH and spinal cord; the modified index of CDH. We recorded general information, neck disability index (NDI) scores, visual analog scale (VAS) scores of neck and arm of all patients preoperatively and postoperatively at 1‐year follow‐up. The association of preoperative general variables and morphological parameters with clinical outcomes were explored by utilizing logistic regression and receiver operating characteristic curve (ROC) analysis. Results The preoperative neck‐VAS, arm‐VAS, and NDI were significantly decreased after PPECD and remained at a low value at follow‐up. In regards to the morphological parameters of CDH, the mean value of DC‐SC distance, DC‐DP distance, internal diameter of the disc, axial length of CDH, central angle of CDH, and modified index of CDH were 1.61 ± 0.30 cm, 1.66 ± 0.32cm, 1.04 ± 0.21 cm, 0.63 ± 0.19cm, 39.38° ± 11.94°, and 0.39 ± 0.24, respectively. For patients grouped by difference in the recovery rate of NDI and arm‐VAS (excellent improved group, EI; and limited improved group, LI), there were no differences in the age, gender, surgical segments, and morphological parameters, except for the central angle of CDH. According to binary logistic regression analysis, only the preoperative central angle of CDH was significantly associated with postoperative NDI recovery (odds ratio: 0.873; 95% confidence interval: 0.819–0.931, P = 0.002). ROC analysis showed the optimal cut‐off value of the central angle of CDH for predicting the postoperative improvement of functional outcomes is 33.788°. Conclusion Preoperative morphology of CDH is related to the outcomes of CSR patients after PPECD. Patients with a large central angle of CDH (>33.788°) have more likelihood of ameliorating neurological symptoms of CSR. There is the potential to select the central angle of CDH as a predictor for outcomes of PPECD in treating CSR.
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Affiliation(s)
- Yi Liu
- Department of Orthopaedics, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Guo-Ke Tang
- Department of Orthopaedics, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Wei-Heng Wang
- Department of Orthopaedics, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Chang-Gui Shi
- Department of Orthopaedics, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Shuang Wang
- Department of Orthopaedics, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Lei Yu
- Department of Orthopaedics, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Jiang-Ming Yu
- Department of Orthopaedics, Changzheng Hospital, Second Military Medical University, Shanghai, China.,Department of Orthopaedics, Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiao-Jian Ye
- Department of Orthopaedics, Changzheng Hospital, Second Military Medical University, Shanghai, China.,Department of Orthopaedics, Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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12
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Spinal Cord Motion in Degenerative Cervical Myelopathy: The Level of the Stenotic Segment and Gender Cause Altered Pathodynamics. J Clin Med 2021; 10:jcm10173788. [PMID: 34501236 PMCID: PMC8432264 DOI: 10.3390/jcm10173788] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 08/18/2021] [Accepted: 08/20/2021] [Indexed: 12/28/2022] Open
Abstract
In degenerative cervical myelopathy (DCM), focally increased spinal cord motion has been observed for C5/C6, but whether stenoses at other cervical segments lead to similar pathodynamics and how severity of stenosis, age, and gender affect them is still unclear. We report a prospective matched-pair controlled trial on 65 DCM patients. A high-resolution 3D T2 sampling perfection with application-optimized contrasts using different flip angle evolution (SPACE) and a phase-contrast magnetic resonance imaging (MRI) sequence were performed and automatically segmented. Anatomical and spinal cord motion data were assessed per segment from C2/C3 to C7/T1. Spinal cord motion was focally increased at a level of stenosis among patients with stenosis at C4/C5 (n = 14), C5/C6 (n = 33), and C6/C7 (n = 10) (p < 0.033). Patients with stenosis at C2/C3 (n = 2) and C3/C4 (n = 6) presented a similar pattern, not reaching significance. Gender was a significant predictor of higher spinal cord dynamics among men with stenosis at C5/C6 (p = 0.048) and C6/C7 (p = 0.033). Age and severity of stenosis did not relate to spinal cord motion. Thus, the data demonstrates focally increased spinal cord motion depending on the specific level of stenosis. Gender-related effects lead to dynamic alterations among men with stenosis at C5/C6 and C6/C7. The missing relation of motion to severity of stenosis underlines a possible additive diagnostic value of spinal cord motion analysis in DCM.
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13
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Laakso H, Lehto LJ, Paasonen J, Salo R, Canna A, Lavrov I, Michaeli S, Gröhn O, Mangia S. Spinal cord fMRI with MB-SWIFT for assessing epidural spinal cord stimulation in rats. Magn Reson Med 2021; 86:2137-2145. [PMID: 34002880 PMCID: PMC8360072 DOI: 10.1002/mrm.28844] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 04/01/2021] [Accepted: 04/26/2021] [Indexed: 12/27/2022]
Abstract
Purpose Electrical epidural spinal cord stimulation (SCS) is used as a treatment for chronic pain as well as to partially restore motor function after a spinal cord injury. Monitoring the spinal cord activity during SCS with fMRI could provide important and objective measures of integrative responses to treatment. Unfortunately, spinal cord fMRI is severely challenged by motion and susceptibility artifacts induced by the implanted electrode and bones. This pilot study introduces multi‐band sweep imaging with Fourier transformation (MB‐SWIFT) technique for spinal cord fMRI during SCS in rats. Given the close to zero acquisition delay and high bandwidth in 3 dimensions, MB‐SWIFT is demonstrated to be highly tolerant to motion and susceptibility‐induced artifacts and thus holds promise for fMRI during SCS. Methods MB‐SWIFT with 0.78 × 0.78 × 1.50 mm3 spatial resolution and 3‐s temporal resolution was used at 9.4 Tesla in rats undergoing epidural SCS at different frequencies. Its performance was compared with spin echo EPI. The origin of the functional contrast was also explored using suppression bands. Results MB‐SWIFT was tolerant to electrode‐induced artifacts and respiratory motion, leading to substantially higher fMRI sensitivity than spin echo fMRI. Clear stimulation frequency‐dependent responses to SCS were detected in the rat spinal cord close to the stimulation site. The origin of MB‐SWIFT fMRI signals was consistent with dominant inflow effects. Conclusion fMRI of the rat spinal cord during SCS can be consistently achieved with MB‐SWIFT, thus providing a valuable experimental framework for assessing the effects of SCS on the central nervous system.
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Affiliation(s)
- Hanne Laakso
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland.,Center for Magnetic Resonance in Research, University of Minnesota, Minneapolis, Minnesota, USA
| | - Lauri J Lehto
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland.,Center for Magnetic Resonance in Research, University of Minnesota, Minneapolis, Minnesota, USA.,Department of Radiology, Kanta-Häme Central Hospital, Hämeenlinna, Finland
| | - Jaakko Paasonen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Raimo Salo
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Antonietta Canna
- Center for Magnetic Resonance in Research, University of Minnesota, Minneapolis, Minnesota, USA.,Department of Medicine, Surgery and Dentistry, "Scuola Medica Salernitana", Salerno, Italy
| | - Igor Lavrov
- Kazan Federal University, Kazan, Russia.,Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA.,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Shalom Michaeli
- Center for Magnetic Resonance in Research, University of Minnesota, Minneapolis, Minnesota, USA
| | - Olli Gröhn
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Silvia Mangia
- Center for Magnetic Resonance in Research, University of Minnesota, Minneapolis, Minnesota, USA
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14
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Wolf K, Reisert M, Beltrán SF, Klingler JH, Hubbe U, Krafft AJ, Egger K, Hohenhaus M. Focal cervical spinal stenosis causes mechanical strain on the entire cervical spinal cord tissue - A prospective controlled, matched-pair analysis based on phase-contrast MRI. NEUROIMAGE-CLINICAL 2021; 30:102580. [PMID: 33578322 PMCID: PMC7875814 DOI: 10.1016/j.nicl.2021.102580] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 11/30/2020] [Accepted: 01/21/2021] [Indexed: 12/27/2022]
Abstract
BACKGROUND Focally increased spinal cord motion at the level of cervical spinal stenosis has been revealed by phase-contrast MRI (PC-MRI). OBJECTIVE To investigate spinal cord motion among patients suffering of degenerative cervical myelopathy (DCM) across the entire cervical spine applying automated segmentation and standardized PC-MRI post-processing protocols. METHODS Prospective, matched-pair controlled trial on 29 patients with stenosis at C5/C6. MRI-protocol covering all cervical segments: 3D T2-SPACE, prospectively ECG-triggered sagittal PC-MRI. Segmentation by trained 3D hierarchical deep convolutional neural network and data processing were conducted via in-house software pipeline. Parameters per segment: maximum velocity, peak-to-peak (PTP)-amplitude, total displacement, PTP-amplitudeHB (PTP-amplitude per duration of heartbeat), and, for characterization of intraindividual alterations, the PTP-amplitude index between the cervical segments C3/C4-C7/T1 and C2/C3. RESULTS Spinal cord motion was increased at C4/C5, C5/C6 and C6/C7 among patients (all parameters, p < 0.001-0.025). The PTP-amplitude index revealed an increase from C3/C4 to C4/C5 (p = 0.002), C4/C5 to C5/C6 (p = 0.037) and a decrease from C5/C6 to C6/C7 and C6/C7 to C7/T1 (p < 0.001, each). This implied an up-building stretch on spinal cord tissue cranial and a mechanical compression caudal of the stenotic level. Furthermore, significant far range effects across the entire cervical spinal cord were observed (e.g. PTP-amplitude C2/C3 vs. C6/C7, p = 0.026) in contrast to controls (p = 1.00). CONCLUSION This study revealed the nature and extends of mechanical stress on the entire cervical spinal cord tissue due to focal stenosis. These pathophysiological alterations of spinal cord motion can be expected to be clinically relevant.
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Affiliation(s)
- Katharina Wolf
- Department of Neurology and Neurophysiology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany.
| | - Marco Reisert
- Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Saúl Felipe Beltrán
- Department of Neurology and Neurophysiology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Jan-Helge Klingler
- Department of Neurosurgery, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Ulrich Hubbe
- Department of Neurosurgery, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Axel J Krafft
- Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Karl Egger
- Department of Neuroradiology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany; Department of Radiology, Tauernklinikum Zell am See/Mittersill, Salzburg, Austria
| | - Marc Hohenhaus
- Department of Neurosurgery, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
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15
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Dauleac C, Bannier E, Cotton F, Frindel C. Effect of distortion corrections on the tractography quality in spinal cord diffusion-weighted imaging. Magn Reson Med 2021; 85:3241-3255. [PMID: 33475180 DOI: 10.1002/mrm.28665] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 12/03/2020] [Accepted: 12/10/2020] [Indexed: 12/20/2022]
Abstract
PURPOSE To assess the impact of a different distortion correction (DC) method and patient geometry (sagittal balance) on the quality of spinal cord tractography rendering according to different tractography approaches. METHODS Forty-four adults free of spinal cord diseases underwent cervical diffusion-weighted imaging. The phase-encoding direction was head→foot. Sequence with opposed polarities (foot→head) was acquired to perform DC. Eddy-current, motion effects, and susceptibility artifact correction methods were used for DC, and two deterministic and one probabilistic tractography approaches were evaluated using MRtrix and DSI Studio tractography software. Fiber length and number of fibers were extracted to evaluate the quality of the tractography rendering. For each subject, cervical lordosis was measured to assess patient geometry. The angle between the main direction of the spinal cord and the orientation of the acquisition box were computed at each spine level to assess acquisition geometry and define an angle threshold for which a tractography of good quality is no longer possible. RESULTS There was a significant improvement in tractography quality after performing DC with susceptibility artifact correction using a deterministic approach based on tensor. Before DC, the angle threshold was defined at C6 (15.2°) compared with C7 (21.9°) after corrections, demonstrating the importance of spinal cord angulation for DC. CONCLUSION The impact of DC on tractography quality is greatly impacted by acquisition geometry. To obtain a good-quality tractography, we propose as a future perspective to adapt the acquisition geometry to that of the patient by automatically adjusting the acquisition box.
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Affiliation(s)
- Corentin Dauleac
- Department of Neurosurgery, Hôpital neurologique et neurochirurgical Pierre Wertheimer, Hospices Civils de Lyon, Lyon, France.,Université de Lyon, Université Claude Bernard Lyon I, Lyon, France.,Laboratoire CREATIS, CNRS UMR5220, INSA-Lyon, Université de Lyon I, Inserm U1206, Lyon, France
| | - Elise Bannier
- Université de Rennes, Inria, CNRS, Inserm, IRISA UMR 6074, Empenn, France.,Department of Radiology, CHU de Rennes, Rennes, France
| | - François Cotton
- Université de Lyon, Université Claude Bernard Lyon I, Lyon, France.,Laboratoire CREATIS, CNRS UMR5220, INSA-Lyon, Université de Lyon I, Inserm U1206, Lyon, France.,Department of Radiology, Centre Hospitalier de Lyon Sud, Hospices Civils de Lyon, Lyon, France
| | - Carole Frindel
- Université de Lyon, Université Claude Bernard Lyon I, Lyon, France.,Laboratoire CREATIS, CNRS UMR5220, INSA-Lyon, Université de Lyon I, Inserm U1206, Lyon, France
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16
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Oztek MA, Mayr NA, Mossa-Basha M, Nyflot M, Sponseller PA, Wu W, Hofstetter CP, Saigal R, Bowen SR, Hippe DS, Yuh WTC, Stewart RD, Lo SS. The Dancing Cord: Inherent Spinal Cord Motion and Its Effect on Cord Dose in Spine Stereotactic Body Radiation Therapy. Neurosurgery 2020; 87:1157-1166. [PMID: 32497210 PMCID: PMC8184298 DOI: 10.1093/neuros/nyaa202] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 03/19/2020] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Spinal cord dose limits are critically important for the safe practice of spine stereotactic body radiotherapy (SBRT). However, the effect of inherent spinal cord motion on cord dose in SBRT is unknown. OBJECTIVE To assess the effects of cord motion on spinal cord dose in SBRT. METHODS Dynamic balanced fast field echo (BFFE) magnetic resonance imaging (MRI) was obtained in 21 spine metastasis patients treated with SBRT. Planning computed tomography (CT), conventional static T2-weighted MRI, BFFE MRI, and dose planning data were coregistered. Spinal cord from the dynamic BFFE images (corddyn) was compared with the T2-weighted MRI (cordstat) to analyze motion of corddyn beyond the cordstat (Dice coefficient, Jaccard index), and beyond cordstat with added planning organ at risk volume (PRV) margins. Cord dose was compared between cordstat, and corddyn (Wilcoxon signed-rank test). RESULTS Dice coefficient (0.70-0.95, median 0.87) and Jaccard index (0.54-0.90, median 0.77) demonstrated motion of corddyn beyond cordstat. In 62% of the patients (13/21), the dose to corddyn exceeded that of cordstat by 0.6% to 13.8% (median 4.3%). The corddyn spatially excursed outside the 1-mm PRV margin of cordstat in 9 patients (43%); among these dose to corddyn exceeded dose to cordstat >+ 1-mm PRV margin in 78% of the patients (7/9). Corddyn did not excurse outside the 1.5-mm or 2-mm PRV cord cordstat margin. CONCLUSION Spinal cord motion may contribute to increases in radiation dose to the cord from SBRT for spine metastasis. A PRV margin of at least 1.5 to 2 mm surrounding the cord should be strongly considered to account for inherent spinal cord motion.
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Affiliation(s)
- Murat Alp Oztek
- Department of Radiology, University of Washington School of Medicine, Seattle, Washington
| | - Nina A Mayr
- Department of Radiation Oncology, University of Washington School of Medicine, Seattle, Washington
| | - Mahmud Mossa-Basha
- Department of Radiology, University of Washington School of Medicine, Seattle, Washington
| | - Matthew Nyflot
- Department of Radiology, University of Washington School of Medicine, Seattle, Washington.,Department of Radiation Oncology, University of Washington School of Medicine, Seattle, Washington
| | - Patricia A Sponseller
- Department of Radiation Oncology, University of Washington School of Medicine, Seattle, Washington
| | - Wei Wu
- Department of Radiology, University of Washington School of Medicine, Seattle, Washington
| | - Christoph P Hofstetter
- Department of Neurological Surgery, University of Washington School of Medicine, Seattle, Washington
| | - Rajiv Saigal
- Department of Neurological Surgery, University of Washington School of Medicine, Seattle, Washington
| | - Stephen R Bowen
- Department of Radiology, University of Washington School of Medicine, Seattle, Washington.,Department of Radiation Oncology, University of Washington School of Medicine, Seattle, Washington
| | - Daniel S Hippe
- Department of Radiology, University of Washington School of Medicine, Seattle, Washington
| | - William T C Yuh
- Department of Radiology, University of Washington School of Medicine, Seattle, Washington
| | - Robert D Stewart
- Department of Radiation Oncology, University of Washington School of Medicine, Seattle, Washington
| | - Simon S Lo
- Department of Radiation Oncology, University of Washington School of Medicine, Seattle, Washington
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17
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Lévy S, Roche PH, Guye M, Callot V. Feasibility of human spinal cord perfusion mapping using dynamic susceptibility contrast imaging at 7T: Preliminary results and identified guidelines. Magn Reson Med 2020; 85:1183-1194. [PMID: 33151009 DOI: 10.1002/mrm.28559] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 09/28/2020] [Accepted: 09/29/2020] [Indexed: 12/14/2022]
Abstract
PURPOSE To explore the feasibility of dynamic susceptibility contrast MRI at 7 Tesla for human spinal cord perfusion mapping and fill the gap between brain and spinal cord perfusion mapping techniques. METHODS Acquisition protocols for high-resolution single shot EPI in the spinal cord were optimized for both spin-echo and gradient-echo preparations, including cardiac gating, acquisition times and breathing cycle recording. Breathing-induced MRI signal fluctuations were investigated in healthy volunteers. A specific image- and signal-processing pipeline was implemented to address them. Dynamic susceptibility contrast was then evaluated in 3 healthy volunteers and 5 patients. Bolus depiction on slice-wise signal within cord was investigated, and maps of relative perfusion indices were computed. RESULTS Signal fluctuations were increased by 1.9 and 2.3 in free-breathing compared to apnea with spin-echo and gradient-echo, respectively. The ratio between signal fluctuations and bolus peak in healthy volunteers was 5.0% for spin-echo and 3.8% for gradient-echo, allowing clear depiction of the bolus on every slice and yielding relative blood flow and volume maps exhibiting the expected higher perfusion of gray matter. However, signal fluctuations in patients were increased by 4 in average (using spin-echo), compromising the depiction of the bolus in slice-wise signal. Moreover, 3 of 18 slices had to be discarded because of fat-aliasing artifacts. CONCLUSION Dynamic susceptibility contrast MRI at 7 Tesla showed great potential for spinal cord perfusion mapping with a reliability never achieved thus far for single subject and single slice measurements. Signal stability needs to be improved in acquisition conditions associated with patients; guidelines to achieve that have been identified and shared.
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Affiliation(s)
- Simon Lévy
- Aix-Marseille Univ, CNRS, CRMBM, Marseille, France.,APHM, Hopital Universitaire Timone, CEMEREM, Marseille, France.,Aix-Marseille Univ, Univ Gustave Eiffel, LBA, Marseille, France.,iLab-Spine International Associated Laboratory, Marseille-Montreal, France-Canada
| | - Pierre-Hugues Roche
- iLab-Spine International Associated Laboratory, Marseille-Montreal, France-Canada.,Neurosurgery Department, APHM, Hopital Nord, Marseille, France
| | - Maxime Guye
- Aix-Marseille Univ, CNRS, CRMBM, Marseille, France.,APHM, Hopital Universitaire Timone, CEMEREM, Marseille, France
| | - Virginie Callot
- Aix-Marseille Univ, CNRS, CRMBM, Marseille, France.,APHM, Hopital Universitaire Timone, CEMEREM, Marseille, France.,iLab-Spine International Associated Laboratory, Marseille-Montreal, France-Canada
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18
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Geldschläger O, Bosch D, Avdievich NI, Henning A. Ultrahigh-resolution quantitative spinal cord MRI at 9.4T. Magn Reson Med 2020; 85:1013-1027. [PMID: 32789980 DOI: 10.1002/mrm.28455] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 07/06/2020] [Accepted: 07/10/2020] [Indexed: 11/08/2022]
Abstract
PURPOSE To present the results of the first human spinal cord in vivo MRI scans at 9.4T. METHODS A human brain coil was used to image the human spinal cord at 9.4T. All anatomical images were acquired with a T2 *-weighted gradient-echo sequence. A comparison of the influence of four different B0 shimming routines on the image quality was performed. Intrinsic signal-to-noise-ratio maps were determined using a pseudo-multiple replica approach. Measurements with different echo times were compared and processed to one multiecho data image combination image. Based on the multiecho acquisitions, T2 *-relaxation time maps were calculated. Algorithmic spinal cord detection and gray matter/white matter segmentation were tested. RESULTS An echo time between 9 and 13.8 ms compromised best between gray matter/white matter contrast and image quality. A maximum in-plane resolution of 0.15 × 0.15 mm2 was achieved for anatomical images. These images offered excellent image quality and made small structures of the spinal cord visible. The scanner vendor implemented B0 shimming routine performed best during this work. Intrinsic signal-to-noise-ratio values of between 6600 and 8060 at the upper cervical spinal cord were achieved. Detection and segmentation worked reliably. An average T2 *-time of 24.88 ms ± 6.68 ms for gray matter and 19.37 ms ± 8.66 ms for white matter was calculated. CONCLUSION The proposed human brain coil can be used to image the spinal cord. The maximum in-plane resolution in this work was higher compared with the 7T results from the literature. The 9.4T acquisitions made the small structures of the spinal cord clearly visible.
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Affiliation(s)
- Ole Geldschläger
- High-Field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Dario Bosch
- High-Field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.,Biomedical Magnetic Resonance, University Hospital Tübingen, Tübingen, Germany
| | - Nikolai I Avdievich
- High-Field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Anke Henning
- High-Field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.,Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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Esposito MF, Malayil R, Hanes M, Deer T. Unique Characteristics of the Dorsal Root Ganglion as a Target for Neuromodulation. PAIN MEDICINE 2020; 20:S23-S30. [PMID: 31152179 PMCID: PMC6544557 DOI: 10.1093/pm/pnz012] [Citation(s) in RCA: 114] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Objective The dorsal root ganglion (DRG) is a novel target for neuromodulation, and DRG stimulation is proving to be a viable option in the treatment of chronic intractable neuropathic pain. Although the overall principle of conventional spinal cord stimulation (SCS) and DRG stimulation—in which an electric field is applied to a neural target with the intent of affecting neural pathways to decrease pain perception—is similar, there are significant differences in the anatomy and physiology of the DRG that make it an ideal target for neuromodulation and may account for the superior outcomes observed in the treatment of certain chronic neuropathic pain states. This review highlights the anatomy of the DRG, its function in maintaining homeostasis and its role in neuropathic pain, and the unique value of DRG as a target in neuromodulation for pain. Methods A narrative literature review was performed. Results Overall, the DRG is a critical structure in sensory transduction and modulation, including pain transmission and the maintenance of persistent neuropathic pain states. Unique characteristics including selective somatic organization, specialized membrane characteristics, and accessible and consistent location make the DRG an ideal target for neuromodulation. Because DRG stimulation directly recruits the somata of primary sensory neurons and harnesses the filtering capacity of the pseudounipolar neural architecture, it is differentiated from SCS, peripheral nerve stimulation, and other neuromodulation options. Conclusions There are several advantages to targeting the DRG, including lower energy usage, more focused and posture-independent stimulation, reduced paresthesia, and improved clinical outcomes.
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Affiliation(s)
| | - Rudy Malayil
- St. Mary's Pain Relief Specialists, Huntington, West Virginia
| | | | - Timothy Deer
- The Spine and Nerve Center of the Virginias, Charleston, West Virginia, USA
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20
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Spinal cord stimulation programming: a crash course. Neurosurg Rev 2020; 44:709-720. [PMID: 32291559 DOI: 10.1007/s10143-020-01299-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 02/20/2020] [Accepted: 04/02/2020] [Indexed: 12/19/2022]
Abstract
The aim of this comprehensive review is to provide an instructional guide for providers regarding the parameters and programming of spinal cord stimulation (SCS) devices. Knowing these fundamentals will aid in providing superior pain relief to patients. SCS has four programmable parameters: contact (electrode) selection, amplitude, pulse width, and frequency. Each parameter needs to be accounted for when assessing which program works for which patient. Traditional open-loop systems allow for different "programs," or combinations of these four parameters, to be pre-set by the provider and medical device representative. These allow for flexibility in the type of stimulation delivered to the patient depending on activity. Patients are also given control over programs and changing the amplitudes of these programs. However, some open-loop systems place the burden of toggling between programs to manage pain control on patients, though this tends to be less in subparesthesia programs. Newer closed-loop systems make it possible for stimulation settings to automatically adjust in response to accelerometry and evoked compound action potential feedback, and therefore have the potential to streamline the patient experience. This article provides practitioners with the basic knowledge of SCS parameters and programming systems. Understanding their use is essential to providing optimal pain relief to patients.
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21
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Lévy S, Rapacchi S, Massire A, Troalen T, Feiweier T, Guye M, Callot V. Intravoxel Incoherent Motion at 7 Tesla to quantify human spinal cord perfusion: limitations and promises. Magn Reson Med 2020; 84:1198-1217. [DOI: 10.1002/mrm.28195] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 12/16/2019] [Accepted: 01/10/2020] [Indexed: 12/15/2022]
Affiliation(s)
- Simon Lévy
- Aix‐Marseille Univ, CNRS, CRMBM Marseille France
- APHM, Hopital Universitaire Timone, CEMEREM Marseille France
- Aix‐Marseille Univ, IFSTTAR, LBA Marseille France
- iLab‐Spine International Associated Laboratory Marseille‐Montreal France‐Canada
| | - Stanislas Rapacchi
- Aix‐Marseille Univ, CNRS, CRMBM Marseille France
- APHM, Hopital Universitaire Timone, CEMEREM Marseille France
| | - Aurélien Massire
- Aix‐Marseille Univ, CNRS, CRMBM Marseille France
- APHM, Hopital Universitaire Timone, CEMEREM Marseille France
- iLab‐Spine International Associated Laboratory Marseille‐Montreal France‐Canada
| | | | | | - Maxime Guye
- Aix‐Marseille Univ, CNRS, CRMBM Marseille France
- APHM, Hopital Universitaire Timone, CEMEREM Marseille France
| | - Virginie Callot
- Aix‐Marseille Univ, CNRS, CRMBM Marseille France
- APHM, Hopital Universitaire Timone, CEMEREM Marseille France
- iLab‐Spine International Associated Laboratory Marseille‐Montreal France‐Canada
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22
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Wolf K, Krafft AJ, Egger K, Klingler JH, Hubbe U, Reisert M, Hohenhaus M. Assessment of spinal cord motion as a new diagnostic MRI-parameter in cervical spinal canal stenosis: study protocol on a prospective longitudinal trial. J Orthop Surg Res 2019; 14:321. [PMID: 31606049 PMCID: PMC6790032 DOI: 10.1186/s13018-019-1381-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 09/16/2019] [Indexed: 01/28/2023] Open
Abstract
Background Increased spinal cord motion has been proven to be a relevant finding within spinal canal stenosis disclosed by phase-contrast MRI (PC-MRI). Adapted PC-MRI is a suitable and reliable method within the well deliberated setting. As the decision between conservative and operative treatment can be challenging in some cases, further diagnostic marker would facilitate the diagnostic process. We hypothesize that increased spinal cord motion will correlate to clinical course and functional impairment and will contribute as a new diagnostic marker. Methods A monocentric, prospective longitudinal observational trial on cervical spinal canal stenosis will be conducted at the University Medical Center Freiburg. Patients (n = 130) with relevant cervical spinal canal stenosis, being defined by at least contact to the spinal cord, will be included. Also, we will examine a control group of healthy volunteers (n = 20) as proof-of-principle. We will observe two openly assigned branches of participants undergoing conservative and surgical decompressive treatment (based on current German Guidelines) over a time course of 12 month, including a total of 4 visits. We will conduct a broad assessment of clinical parameters, standard scores and gradings, electrophysiological measurements, standard MRI, and adapted functional PC-MRI of spinal cord motion. Primary endpoint is the evaluation of an expected negative correlation of absolute spinal cord displacement to clinical impairment. Secondary endpoints are the evaluation of positive correlation of increased absolute spinal cord displacement to prolonged evoked potentials, prediction of clinical course by absolute spinal cord displacement, and demonstration of normalized spinal cord motion after decompressive surgery. Discussion With the use of adapted, non-invasive PC-MRI as a quantitative method for assessment of spinal cord motion, further objective diagnostic information can be gained, that might improve the therapeutic decision-making process. This study will offer the needed data in order to establish PC-MRI on spinal cord motion within the diagnostic work-up of patients suffering from spinal canal stenosis. Trial registration German Clinical Trials Register, ID: DRKS00012962, Register date 2018/01/17
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Affiliation(s)
- Katharina Wolf
- Department of Neurology and Neurophysiology, Faculty of Medicine, University of Freiburg, Breisacher Straße 64, 79106, Freiburg, Germany.
| | - Axel J Krafft
- Department of Radiology, Medical Physics, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Karl Egger
- Department of Neuroradiology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Jan-Helge Klingler
- Department of Neurosurgery, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Ulrich Hubbe
- Department of Neurosurgery, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Marco Reisert
- Department of Radiology, Medical Physics, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Marc Hohenhaus
- Department of Neurosurgery, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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23
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Tsagkas C, Horvath A, Altermatt A, Pezold S, Weigel M, Haas T, Amann M, Kappos L, Sprenger T, Bieri O, Cattin P, Parmar K. Automatic Spinal Cord Gray Matter Quantification: A Novel Approach. AJNR Am J Neuroradiol 2019; 40:1592-1600. [PMID: 31439628 DOI: 10.3174/ajnr.a6157] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 06/25/2019] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND PURPOSE Currently, accurate and reproducible spinal cord GM segmentation remains challenging and a noninvasive broadly accepted reference standard for spinal cord GM measurements is still a matter of ongoing discussion. Our aim was to assess the reproducibility and accuracy of cervical spinal cord GM and WM cross-sectional area measurements using averaged magnetization inversion recovery acquisitions images and a fully-automatic postprocessing segmentation algorithm. MATERIALS AND METHODS The cervical spinal cord of 24 healthy subjects (14 women; mean age, 40 ± 11 years) was scanned in a test-retest fashion on a 3T MR imaging system. Twelve axial averaged magnetization inversion recovery acquisitions slices were acquired over a 48-mm cord segment. GM and WM were both manually segmented by 2 experienced readers and compared with an automatic variational segmentation algorithm with a shape prior modified for 3D data with a slice similarity prior. Precision and accuracy of the automatic method were evaluated using coefficients of variation and Dice similarity coefficients. RESULTS The mean GM area was 17.20 ± 2.28 mm2 and the mean WM area was 72.71 ± 7.55 mm2 using the automatic method. Reproducibility was high for both methods, while being better for the automatic approach (all mean automatic coefficients of variation, ≤4.77%; all differences, P < .001). The accuracy of the automatic method compared with the manual reference standard was excellent (mean Dice similarity coefficients: 0.86 ± 0.04 for GM and 0.90 ± 0.03 for WM). The automatic approach demonstrated similar coefficients of variation between intra- and intersession reproducibility as well as among all acquired spinal cord slices. CONCLUSIONS Our novel approach including the averaged magnetization inversion recovery acquisitions sequence and a fully-automated postprocessing segmentation algorithm demonstrated an accurate and reproducible spinal cord GM and WM segmentation. This pipeline is promising for both the exploration of longitudinal structural GM changes and application in clinical settings in disorders affecting the spinal cord.
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Affiliation(s)
- C Tsagkas
- From the Neurologic Clinic and Policlinic (C.T., M.A., L.K., T.S., K.P.), Department of Medicine and Biomedical Engineering.,Translational Imaging in Neurology Basel (C.T., A.A., M.A., M.W., L.K., K.P.), Department of Medicine and Biomedical Engineering.,Medical Image Analysis Center (C.T., A.A., M.A.), Basel, Switzerland
| | - A Horvath
- Department of Biomedical Engineering (A.H., A.A., S.P., M.W., O.B., P.C.), University of Basel, Allschwil, Switzerland
| | - A Altermatt
- Translational Imaging in Neurology Basel (C.T., A.A., M.A., M.W., L.K., K.P.), Department of Medicine and Biomedical Engineering.,Medical Image Analysis Center (C.T., A.A., M.A.), Basel, Switzerland.,Department of Biomedical Engineering (A.H., A.A., S.P., M.W., O.B., P.C.), University of Basel, Allschwil, Switzerland
| | - S Pezold
- Department of Biomedical Engineering (A.H., A.A., S.P., M.W., O.B., P.C.), University of Basel, Allschwil, Switzerland
| | - M Weigel
- Translational Imaging in Neurology Basel (C.T., A.A., M.A., M.W., L.K., K.P.), Department of Medicine and Biomedical Engineering.,Division of Radiological Physics (M.W., T.H., O.B.), Department of Radiology.,Department of Biomedical Engineering (A.H., A.A., S.P., M.W., O.B., P.C.), University of Basel, Allschwil, Switzerland
| | - T Haas
- Division of Radiological Physics (M.W., T.H., O.B.), Department of Radiology
| | - M Amann
- From the Neurologic Clinic and Policlinic (C.T., M.A., L.K., T.S., K.P.), Department of Medicine and Biomedical Engineering.,Translational Imaging in Neurology Basel (C.T., A.A., M.A., M.W., L.K., K.P.), Department of Medicine and Biomedical Engineering.,Division of Diagnostic and Interventional Neuroradiology (M.A.), Department of Radiology, University Hospital Basel, University of Basel, Basel, Switzerland.,Medical Image Analysis Center (C.T., A.A., M.A.), Basel, Switzerland
| | - L Kappos
- From the Neurologic Clinic and Policlinic (C.T., M.A., L.K., T.S., K.P.), Department of Medicine and Biomedical Engineering.,Translational Imaging in Neurology Basel (C.T., A.A., M.A., M.W., L.K., K.P.), Department of Medicine and Biomedical Engineering
| | - T Sprenger
- From the Neurologic Clinic and Policlinic (C.T., M.A., L.K., T.S., K.P.), Department of Medicine and Biomedical Engineering.,Department of Neurology (T.S.), DKD HELIOS Klinik, Wiesbaden, Germany
| | - O Bieri
- Division of Radiological Physics (M.W., T.H., O.B.), Department of Radiology.,Department of Biomedical Engineering (A.H., A.A., S.P., M.W., O.B., P.C.), University of Basel, Allschwil, Switzerland
| | - P Cattin
- Department of Biomedical Engineering (A.H., A.A., S.P., M.W., O.B., P.C.), University of Basel, Allschwil, Switzerland
| | - K Parmar
- From the Neurologic Clinic and Policlinic (C.T., M.A., L.K., T.S., K.P.), Department of Medicine and Biomedical Engineering .,Translational Imaging in Neurology Basel (C.T., A.A., M.A., M.W., L.K., K.P.), Department of Medicine and Biomedical Engineering
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24
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Reynolds BB, By S, Weinberg QR, Witt AA, Newton AT, Feiler HR, Ramkorun B, Clayton DB, Couture P, Martus JE, Adams M, Wellons JC, Smith SA, Bhatia A. Quantification of DTI in the Pediatric Spinal Cord: Application to Clinical Evaluation in a Healthy Patient Population. AJNR Am J Neuroradiol 2019; 40:1236-1241. [PMID: 31196859 PMCID: PMC7048550 DOI: 10.3174/ajnr.a6104] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 05/16/2019] [Indexed: 12/18/2022]
Abstract
BACKGROUND AND PURPOSE The purpose of the study is to characterize diffusion tensor imaging indices in the developing spinal cord, evaluating differences based on age and cord region. Describing the progression of DTI indices in the pediatric cord increases our understanding of spinal cord development. MATERIALS AND METHODS A retrospective analysis was performed on DTI acquired in 121 pediatric patients (mean, 8.6 years; range, 0.3-18.0 years) at Monroe Carell Jr. Children's Hospital at Vanderbilt from 2017 to 2018. Diffusion-weighted images (15 directions; b = 750 s/mm2; slice thickness, 5 mm; in-plane resolution, 1.0 × 1.0 mm2) were acquired on a 3T scanner in the cervicothoracic and/or thoracolumbar cord. Manual whole-cord segmentation was performed. Images were masked and further segmented into cervical, upper thoracic, thoracolumbar, and conus regions. Analyses of covariance were performed for each DTI-derived index to investigate how age affects diffusion across cord regions, and 95% confidence intervals were calculated across age for each derived index and region. Post hoc testing was performed to analyze regional differences. RESULTS Analyses of covariance revealed significant correlations of age with axial diffusivity, mean diffusivity, and fractional anisotropy (all, P < .001). There were also significant differences among cord regions for axial diffusivity, radial diffusivity, mean diffusivity, and fractional anisotropy (all, P < .001). CONCLUSIONS This research demonstrates that diffusion evolves in the pediatric spinal cord during development, dependent on both cord region and the diffusion index of interest. Future research could investigate how diffusion may be affected by common pediatric spinal pathologies.
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Affiliation(s)
- B B Reynolds
- Institute of Imaging Science (B.B.R., S.B., Q.R.W., A.A.W., A.T.N., H.R.F., B.R., S.A.S., A.B.), Vanderbilt University, Nashville, Tennessee
| | - S By
- Institute of Imaging Science (B.B.R., S.B., Q.R.W., A.A.W., A.T.N., H.R.F., B.R., S.A.S., A.B.), Vanderbilt University, Nashville, Tennessee
| | - Q R Weinberg
- Institute of Imaging Science (B.B.R., S.B., Q.R.W., A.A.W., A.T.N., H.R.F., B.R., S.A.S., A.B.), Vanderbilt University, Nashville, Tennessee
| | - A A Witt
- Institute of Imaging Science (B.B.R., S.B., Q.R.W., A.A.W., A.T.N., H.R.F., B.R., S.A.S., A.B.), Vanderbilt University, Nashville, Tennessee
| | - A T Newton
- From the Department of Radiology and Radiological Sciences (A.T.N., P.C., S.A.S., A.B.).,Pediatrics (A.T.N.).,Institute of Imaging Science (B.B.R., S.B., Q.R.W., A.A.W., A.T.N., H.R.F., B.R., S.A.S., A.B.), Vanderbilt University, Nashville, Tennessee
| | - H R Feiler
- Institute of Imaging Science (B.B.R., S.B., Q.R.W., A.A.W., A.T.N., H.R.F., B.R., S.A.S., A.B.), Vanderbilt University, Nashville, Tennessee
| | - B Ramkorun
- Institute of Imaging Science (B.B.R., S.B., Q.R.W., A.A.W., A.T.N., H.R.F., B.R., S.A.S., A.B.), Vanderbilt University, Nashville, Tennessee
| | | | - P Couture
- From the Department of Radiology and Radiological Sciences (A.T.N., P.C., S.A.S., A.B.)
| | - J E Martus
- Division of Pediatric Orthopaedics (J.E.M.), Monroe Carell Jr. Children's Hospital at Vanderbilt, Nashville, Tennessee
| | | | - J C Wellons
- From the Department of Radiology and Radiological Sciences (A.T.N., P.C., S.A.S., A.B.).,Department of Ophthalmology (S.A.S., J.C.W. III), Vanderbilt University Medical Center, Nashville, Tennessee
| | - S A Smith
- From the Department of Radiology and Radiological Sciences (A.T.N., P.C., S.A.S., A.B.).,Department of Biomedical Engineering (S.A.S.).,Institute of Imaging Science (B.B.R., S.B., Q.R.W., A.A.W., A.T.N., H.R.F., B.R., S.A.S., A.B.), Vanderbilt University, Nashville, Tennessee.,Department of Ophthalmology (S.A.S., J.C.W. III), Vanderbilt University Medical Center, Nashville, Tennessee
| | - A Bhatia
- From the Department of Radiology and Radiological Sciences (A.T.N., P.C., S.A.S., A.B.) .,Institute of Imaging Science (B.B.R., S.B., Q.R.W., A.A.W., A.T.N., H.R.F., B.R., S.A.S., A.B.), Vanderbilt University, Nashville, Tennessee
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25
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Vannesjo SJ, Clare S, Kasper L, Tracey I, Miller KL. A method for correcting breathing-induced field fluctuations in T2*-weighted spinal cord imaging using a respiratory trace. Magn Reson Med 2019; 81:3745-3753. [PMID: 30737825 PMCID: PMC6492127 DOI: 10.1002/mrm.27664] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 12/01/2018] [Accepted: 12/27/2018] [Indexed: 02/04/2023]
Abstract
PURPOSE Spinal cord MRI at ultrahigh field is hampered by time-varying magnetic fields associated with the breathing cycle, giving rise to ghosting artifacts in multi-shot acquisitions. Here, we suggest a correction approach based on linking the signal from a respiratory bellows to field changes inside the spinal cord. The information is used to correct the data at the image reconstruction level. METHODS The correction was demonstrated in the context of multi-shot T2*-weighted imaging of the cervical spinal cord at 7T. A respiratory trace was acquired during a high-resolution multi-echo gradient-echo sequence, used for structural imaging and quantitative T2* mapping, and a multi-shot EPI time series, as would be suitable for fMRI. The coupling between the trace and the breathing-induced fields was determined by a short calibration scan in each individual. Images were reconstructed with and without trace-based correction. RESULTS In the multi-echo acquisition, breathing-induced fields caused severe ghosting in images with long TE, which led to a systematic underestimation of T2* in the spinal cord. The trace-based correction reduced the ghosting and increased the estimated T2* values. Breathing-related ghosting was also observed in the multi-shot EPI images. The correction largely removed the ghosting, thereby improving the temporal signal-to-noise ratio of the time series. CONCLUSIONS Trace-based retrospective correction of breathing-induced field variations can reduce ghosting and improve quantitative metrics in multi-shot structural and functional T2*-weighted imaging of the spinal cord. The method is straightforward to implement and does not rely on sequence modifications or additional hardware beyond a respiratory bellows.
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Affiliation(s)
- S. Johanna Vannesjo
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Department of Clinical NeurosciencesUniversity of OxfordOxfordUK
| | - Stuart Clare
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Department of Clinical NeurosciencesUniversity of OxfordOxfordUK
| | - Lars Kasper
- Institute for Biomedical EngineeringETH Zurich and University of ZurichZurichSwitzerland
- Translational Neuromodeling Unit, Institute for Biomedical EngineeringUniversity of Zurich and ETH ZurichZurichSwitzerland
| | - Irene Tracey
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Department of Clinical NeurosciencesUniversity of OxfordOxfordUK
| | - Karla L. Miller
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Department of Clinical NeurosciencesUniversity of OxfordOxfordUK
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26
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Ioachim G, Powers JM, Stroman PW. Comparing Coordinated Networks Across the Brainstem and Spinal Cord in the Resting State and Altered Cognitive State. Brain Connect 2019; 9:415-424. [DOI: 10.1089/brain.2018.0659] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Gabriela Ioachim
- Centre for Neuroscience Studies, Queen's University, Kingston, Canada
| | - Jocelyn M. Powers
- Centre for Neuroscience Studies, Queen's University, Kingston, Canada
| | - Patrick W. Stroman
- Centre for Neuroscience Studies, Queen's University, Kingston, Canada
- Department of Biomedical and Molecular Sciences and Queen's University, Kingston, Canada
- Department of Physics, Queen's University, Kingston, Canada
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27
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Xiang M, Chan C, Wang L, Jani K, Holdsworth SJ, Iv M, Pollom EL, Soltys SG. Physiological motion of the optic chiasm and its impact on stereotactic radiosurgery dose. Br J Radiol 2019; 92:20190170. [PMID: 31067077 DOI: 10.1259/bjr.20190170] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
OBJECTIVE Avoidance of radiation-induced optic neuropathy (RION) from stereotactic radiosurgery (SRS) requires precise anatomical localization; however, no prior studies have characterized the physiologic motion of the optic chiasm. We measured the extent of chiasm motion and its impact on SRS dose. METHODS In this cross-sectional study, serial MRI was performed in multiple planes in 11 human subjects without optic pathway abnormalities to determine chiasm motion across time. Subsequently, the measured displacement was applied to the hypothetical chiasm dose received in 11 patients treated with SRS to a perichiasmatic lesion. RESULTS On sagittal images, the average anteroposterior chiasm displacement was 0.51 mm [95% confidence interval (CI) 0.27 - 0.75 mm], and the average superior-inferior displacement was 0.48 mm (95% CI 0.22 - 0.74 mm). On coronal images, the average superior-inferior displacement was 0.42 mm (95% CI 0.13 - 0.71 mm), and the average lateral displacement was 0.75 mm (95% CI 0.42 - 1.08 mm). In 11 patients who underwent SRS to a perichiasmatic lesion, the average displacements increased the maximum chiasm dose (Dmax) by a mean of 14 % (range 6-23 %; p < 0.001). CONCLUSION Average motion of the optic chiasm was approximately 0.50-0.75 mm, which increased chiasm Dmax by a mean of 14%. In the occasional patient with higher-than-average chiasm motion in a region of steep dose gradient, the increase in chiasm Dmax and risk of RION could be even larger. Similarly, previously reported chiasm dose constraints may underestimate the true dose received during radiosurgery. ADVANCES IN KNOWLEDGE To limit the risk of RION, clinicians may consider adding a 0.50-0.75 mm expansion to the chiasm avoidance structure.
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Affiliation(s)
- Michael Xiang
- 1 Department of Radiation Oncology, Stanford University , Stanford, CA , United States of America
| | - Cynthia Chan
- 2 Department of Radiology, Division of Neuroradiology, Stanford University , Stanford, CA , United States of America
| | - Lei Wang
- 1 Department of Radiation Oncology, Stanford University , Stanford, CA , United States of America
| | - Khushboo Jani
- 1 Department of Radiation Oncology, Stanford University , Stanford, CA , United States of America
| | - Samantha J Holdsworth
- 2 Department of Radiology, Division of Neuroradiology, Stanford University , Stanford, CA , United States of America
| | - Michael Iv
- 2 Department of Radiology, Division of Neuroradiology, Stanford University , Stanford, CA , United States of America
| | - Erqi L Pollom
- 1 Department of Radiation Oncology, Stanford University , Stanford, CA , United States of America
| | - Scott G Soltys
- 1 Department of Radiation Oncology, Stanford University , Stanford, CA , United States of America
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28
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Segmental differences of cervical spinal cord motion: advancing from confounders to a diagnostic tool. Sci Rep 2019; 9:7415. [PMID: 31092891 PMCID: PMC6520379 DOI: 10.1038/s41598-019-43908-x] [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] [Received: 01/15/2019] [Accepted: 05/02/2019] [Indexed: 01/01/2023] Open
Abstract
Increased cranio-caudal spinal cord motion is associated with clinical impairment in degenerative cervical myelopathy. However, whether spinal cord motion holds potential as a neuroimaging biomarker requires further validation. Different confounders (i.e. subject characteristics, methodological problems such as phase drift, etc.) on spinal cord motion readouts have to be considered. Twenty-two healthy subjects underwent phase contrast MRI, a subset of subjects (N = 9) had repeated scans. Parameters of interest included amplitude of velocity signal, maximum cranial respectively maximum caudal velocity, displacement (=area under curve of the velocity signal). The cervical spinal cord showed pulse synchronic oscillatory motions with significant differences in all readouts across cervical segments, with a maximum at C5. The Inter-rater reliability was excellent for all readouts. The test-retest reliability was excellent for all parameters at C2 to C6, but not for maximum cranial velocity at C6 and all readouts at C7. Spinal cord motion was correlated with spinal canal size, heart rate and body size. This is the first study to propose a standardized MRI measurement of spinal cord motion for further clinical implementation based on satisfactory phase drift correction and excellent reliability. Understanding the influence of confounders (e.g. structural conditions of the spine) is essential for introducing cord motion into the diagnostic work up.
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29
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El Mendili MM, Querin G, Bede P, Pradat PF. Spinal Cord Imaging in Amyotrophic Lateral Sclerosis: Historical Concepts-Novel Techniques. Front Neurol 2019; 10:350. [PMID: 31031688 PMCID: PMC6474186 DOI: 10.3389/fneur.2019.00350] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Accepted: 03/21/2019] [Indexed: 01/13/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is the most common adult onset motor neuron disease with no effective disease modifying therapies at present. Spinal cord degeneration is a hallmark feature of ALS, highlighted in the earliest descriptions of the disease by Lockhart Clarke and Jean-Martin Charcot. The anterior horns and corticospinal tracts are invariably affected in ALS, but up to recently it has been notoriously challenging to detect and characterize spinal pathology in vivo. With recent technological advances, spinal imaging now offers unique opportunities to appraise lower motor neuron degeneration, sensory involvement, metabolic alterations, and interneuron pathology in ALS. Quantitative spinal imaging in ALS has now been used in cross-sectional and longitudinal study designs, applied to presymptomatic mutation carriers, and utilized in machine learning applications. Despite its enormous clinical and academic potential, a number of physiological, technological, and methodological challenges limit the routine use of computational spinal imaging in ALS. In this review, we provide a comprehensive overview of emerging spinal cord imaging methods and discuss their advantages, drawbacks, and biomarker potential in clinical applications, clinical trial settings, monitoring, and prognostic roles.
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Affiliation(s)
- Mohamed Mounir El Mendili
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, United States.,Biomedical Imaging Laboratory (LIB), Sorbonne University, CNRS, INSERM, Paris, France
| | - Giorgia Querin
- Biomedical Imaging Laboratory (LIB), Sorbonne University, CNRS, INSERM, Paris, France.,Department of Neurology, Pitié-Salpêtrière University Hospital (APHP), Paris, France
| | - Peter Bede
- Biomedical Imaging Laboratory (LIB), Sorbonne University, CNRS, INSERM, Paris, France.,Department of Neurology, Pitié-Salpêtrière University Hospital (APHP), Paris, France.,Computational Neuroimaging Group, Trinity College Dublin, Dublin, Ireland
| | - Pierre-François Pradat
- Biomedical Imaging Laboratory (LIB), Sorbonne University, CNRS, INSERM, Paris, France.,Department of Neurology, Pitié-Salpêtrière University Hospital (APHP), Paris, France
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30
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Yung A, Mattucci S, Bohnet B, Liu J, Fournier C, Tetzlaff W, Kozlowski P, Oxland T. Diffusion tensor imaging shows mechanism-specific differences in injury pattern and progression in rat models of acute spinal cord injury. Neuroimage 2018; 186:43-55. [PMID: 30409758 DOI: 10.1016/j.neuroimage.2018.10.067] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 10/19/2018] [Accepted: 10/25/2018] [Indexed: 10/28/2022] Open
Abstract
We investigate the ability of diffusion tensor imaging (DTI) to distinguish between three experimental rat models of spinal cord injury mechanism - contusion, dislocation, and distraction. Ex vivo DTI scans were performed on cord specimens that were preserved at different time points of the acute injury (3 hr, 24 hr, and 7 days post-injury) across all three injury mechanisms. White matter was classified as abnormal if their DTI metric was substantially different from regional values measured from a set of uninjured controls, thus allowing generation of binary "white matter damage maps" which categorizes each pixel in the DTI image as "normal" or "damaged". Damage classification was most robust using thresholds in the longitudinal diffusivity, which supports previous studies that show that longitudinal diffusivity is the most robust DTI metric in depicting damage in SCI. Furthermore, the spatial damage patterns from all subjects in the same group were consolidated into a "damage occurrence ratio map", which illustrates an average damage shape that characterizes the injury mechanism. Our analysis has yielded a dataset which highlights the differences in injury pattern due to the initial mode of mechanical injury. For example, contusion produced an initial injury that emanated radially outward from the central canal, with subsequent damage along the caudal corticospinal tract and rostral gracile fasciculus; dislocation injuries showed a high level of involvement in the lateral and ventral white matter which became less apparent by 7 days post-injury, and distraction injuries were found to be less focal and more distributed rostrocaudally. This work represents a first step in adopting the use of the primary injury mechanism as a clinical prognostic factor in SCI, which may help to inform the trialing of existing neuroprotective treatment candidates, the development of new therapies as well as personalize the management of SCI for the individual patient.
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Affiliation(s)
- Andrew Yung
- University of British Columbia MRI Research Centre, 2221, Wesbrook Mall, M10 Purdy Pavilion, Vancouver, BC V6T 2B5, Canada.
| | | | - Barry Bohnet
- University of British Columbia MRI Research Centre, 2221, Wesbrook Mall, M10 Purdy Pavilion, Vancouver, BC V6T 2B5, Canada.
| | - Jie Liu
- ICORD, 818 W. 10th Ave., Vancouver, BC V5Z 1M9, Canada.
| | | | | | - Piotr Kozlowski
- University of British Columbia MRI Research Centre, 2221, Wesbrook Mall, M10 Purdy Pavilion, Vancouver, BC V6T 2B5, Canada; ICORD, 818 W. 10th Ave., Vancouver, BC V5Z 1M9, Canada.
| | - Thomas Oxland
- ICORD, 818 W. 10th Ave., Vancouver, BC V5Z 1M9, Canada.
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31
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Powers JM, Ioachim G, Stroman PW. Ten Key Insights into the Use of Spinal Cord fMRI. Brain Sci 2018; 8:E173. [PMID: 30201938 PMCID: PMC6162663 DOI: 10.3390/brainsci8090173] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 08/29/2018] [Accepted: 09/06/2018] [Indexed: 01/27/2023] Open
Abstract
A comprehensive review of the literature-to-date on functional magnetic resonance imaging (fMRI) of the spinal cord is presented. Spinal fMRI has been shown, over more than two decades of work, to be a reliable tool for detecting neural activity. We discuss 10 key points regarding the history, development, methods, and applications of spinal fMRI. Animal models have served a key purpose for the development of spinal fMRI protocols and for experimental spinal cord injury studies. Applications of spinal fMRI span from animal models across healthy and patient populations in humans using both task-based and resting-state paradigms. The literature also demonstrates clear trends in study design and acquisition methods, as the majority of studies follow a task-based, block design paradigm, and utilize variations of single-shot fast spin-echo imaging methods. We, therefore, discuss the similarities and differences of these to resting-state fMRI and gradient-echo EPI protocols. Although it is newly emerging, complex connectivity and network analysis is not only possible, but has also been shown to be reliable and reproducible in the spinal cord for both task-based and resting-state studies. Despite the technical challenges associated with spinal fMRI, this review identifies reliable solutions that have been developed to overcome these challenges.
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Affiliation(s)
- Jocelyn M Powers
- Centre for Neuroscience Studies, Queen's University, Kingston, ON K7L 3N6, Canada.
| | - Gabriela Ioachim
- Centre for Neuroscience Studies, Queen's University, Kingston, ON K7L 3N6, Canada.
| | - Patrick W Stroman
- Centre for Neuroscience Studies, Queen's University, Kingston, ON K7L 3N6, Canada.
- Department of Biomedical Sciences, Queen's University, Kingston, ON K7L 3N6, Canada.
- Department of Physics, Queen's University, Kingston, ON K7L 3N6, Canada.
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32
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Grussu F, Ianuş A, Tur C, Prados F, Schneider T, Kaden E, Ourselin S, Drobnjak I, Zhang H, Alexander DC, Gandini Wheeler-Kingshott CAM. Relevance of time-dependence for clinically viable diffusion imaging of the spinal cord. Magn Reson Med 2018; 81:1247-1264. [PMID: 30229564 PMCID: PMC6586052 DOI: 10.1002/mrm.27463] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 06/28/2018] [Accepted: 06/29/2018] [Indexed: 12/17/2022]
Abstract
Purpose Time‐dependence is a key feature of the diffusion‐weighted (DW) signal, knowledge of which informs biophysical modelling. Here, we study time‐dependence in the human spinal cord, as its axonal structure is specific and different from the brain. Methods We run Monte Carlo simulations using a synthetic model of spinal cord white matter (WM) (large axons), and of brain WM (smaller axons). Furthermore, we study clinically feasible multi‐shell DW scans of the cervical spinal cord (b = 0; b = 711 s mm−2; b = 2855 s mm−2), obtained using three diffusion times (Δ of 29, 52 and 76 ms) from three volunteers. Results Both intra‐/extra‐axonal perpendicular diffusivities and kurtosis excess show time‐dependence in our synthetic spinal cord model. This time‐dependence is reflected mostly in the intra‐axonal perpendicular DW signal, which also exhibits strong decay, unlike our brain model. Time‐dependence of the total DW signal appears detectable in the presence of noise in our synthetic spinal cord model, but not in the brain. In WM in vivo, we observe time‐dependent macroscopic and microscopic diffusivities and diffusion kurtosis, NODDI and two‐compartment SMT metrics. Accounting for large axon calibers improves fitting of multi‐compartment models to a minor extent. Conclusions Time‐dependence of clinically viable DW MRI metrics can be detected in vivo in spinal cord WM, thus providing new opportunities for the non‐invasive estimation of microstructural properties. The time‐dependence of the perpendicular DW signal may feature strong intra‐axonal contributions due to large spinal axon caliber. Hence, a popular model known as “stick” (zero‐radius cylinder) may be sub‐optimal to describe signals from the largest spinal axons.
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Affiliation(s)
- Francesco Grussu
- Queen Square MS Centre, UCL Institute of Neurology, Faculty of Brain Sciences, University College London, London, United Kingdom.,Centre for Medical Image Computing, Department of Computer Science, University College London, London, United Kingdom
| | - Andrada Ianuş
- Centre for Medical Image Computing, Department of Computer Science, University College London, London, United Kingdom.,Champalimaud Centre for the Unknown, Champalimaud Foundation, Lisbon, Portugal
| | - Carmen Tur
- Queen Square MS Centre, UCL Institute of Neurology, Faculty of Brain Sciences, University College London, London, United Kingdom
| | - Ferran Prados
- Queen Square MS Centre, UCL Institute of Neurology, Faculty of Brain Sciences, University College London, London, United Kingdom.,Centre for Medical Image Computing, Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | | | - Enrico Kaden
- Centre for Medical Image Computing, Department of Computer Science, University College London, London, United Kingdom
| | - Sébastien Ourselin
- Centre for Medical Image Computing, Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Ivana Drobnjak
- Centre for Medical Image Computing, Department of Computer Science, University College London, London, United Kingdom
| | - Hui Zhang
- Centre for Medical Image Computing, Department of Computer Science, University College London, London, United Kingdom
| | - Daniel C Alexander
- Centre for Medical Image Computing, Department of Computer Science, University College London, London, United Kingdom.,Clinical Imaging Research Centre, National University of Singapore, Singapore, Singapore
| | - Claudia A M Gandini Wheeler-Kingshott
- Queen Square MS Centre, UCL Institute of Neurology, Faculty of Brain Sciences, University College London, London, United Kingdom.,Brain MRI 3T Research Centre, C. Mondino National Neurological Institute, Pavia, Italy.,Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy
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33
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Hu Y, Jin R, Li G, Luk KDK, Wu EX. Robust spinal cord resting-state fMRI using independent component analysis-based nuisance regression noise reduction. J Magn Reson Imaging 2018; 48:1421-1431. [DOI: 10.1002/jmri.26048] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Accepted: 03/23/2018] [Indexed: 11/11/2022] Open
Affiliation(s)
- Yong Hu
- Department of Orthopaedics and Traumatology, Li Ka Shing Faculty of Medicine; The University of Hong Kong; Pokfulam Hong Kong
| | - Richu Jin
- Department of Orthopaedics and Traumatology, Li Ka Shing Faculty of Medicine; The University of Hong Kong; Pokfulam Hong Kong
| | - Guangsheng Li
- Department of Orthopaedics and Traumatology, Li Ka Shing Faculty of Medicine; The University of Hong Kong; Pokfulam Hong Kong
- Department of Orthopaedics; Affiliated Hospital of Guangdong Medical University; Zhanjiang China
| | - Keith DK Luk
- Department of Orthopaedics and Traumatology, Li Ka Shing Faculty of Medicine; The University of Hong Kong; Pokfulam Hong Kong
| | - Ed. X. Wu
- Department of Electrical and Electronic Engineering, Faculty of Engineering; University of Hong Kong; Pokfulam Hong Kong
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34
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Effect of cardiac-related translational motion in diffusion MRI of the spinal cord. Magn Reson Imaging 2018; 50:119-124. [PMID: 29626518 DOI: 10.1016/j.mri.2018.04.001] [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: 11/13/2017] [Revised: 03/30/2018] [Accepted: 04/03/2018] [Indexed: 11/22/2022]
Abstract
Cardiac-related spinal cord motion affects diffusion-weighted (DWI) signal. The goal of this study was to further quantify the specific detrimental effect of cord translational motion on the DWI signal in order to make better informed decisions about the cost-benefit of cardiac gating. We designed an MRI-compatible phantom mimicking the spinal cord translational motion. Cardiac-gated DWI data were acquired by varying the trigger delay and the b-values. Evaluation of the effect of motion on the DWI signal was done by computing the apparent diffusion coefficient (ADC) along (z-direction) and orthogonal (y- and x-directions) to the phantom. The computed ADCs of the phantom moving along Z were similar for the three orthogonal diffusion-encoding directions, with an average value of 1.65·10-9 , 1.66·10-9 and 1.65·10-9 m2/s along X, Y and Z respectively. DW phase images on the other hand showed the expected linear relationship with phantom velocity. Pure translational motion has minor effect on the diffusion-weighted magnitude signal. The sudden signal drop typically observed in in vivo spinal cord DWI is likely not caused by translational motion of the spinal cord, and possibly originates from non-rigid compression/stretching of the cord and/or from intra-voxel incoherent motion (IVIM).
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35
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Alizadeh M, Fisher J, Saksena S, Sultan Y, Conklin CJ, Middleton DM, Krisa L, Finsterbusch J, Flanders AE, Faro SH, Mulcahey MJ, Mohamed FB. Age related diffusion and tractography changes in typically developing pediatric cervical and thoracic spinal cord. Neuroimage Clin 2018; 18:784-792. [PMID: 29876264 PMCID: PMC5988463 DOI: 10.1016/j.nicl.2018.03.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 03/02/2018] [Accepted: 03/14/2018] [Indexed: 12/14/2022]
Abstract
Background and objective Diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) are two techniques that can measure white matter integrity of the spinal cord. Recently, DTI indices have been shown to change with age. The purpose of this study is (a) to evaluate the maturational states of the entire pediatric spinal cord using DTI and DTT indices including fractional anisotropy (FA), mean diffusivity (MD), mean length of white matter fiber tracts and tract density and (b) to analyze the DTI and DTT parameters along the entire spinal cord as a function of spinal cord levels and age. Method A total of 23 typically developing (TD) pediatric subjects ranging in age from 6 to 16 years old (11.94 ± 3.26 (mean ± standard deviation), 13 females and 10 males) were recruited, and scanned using 3.0 T MR scanner. Reduced FOV diffusion tensor images were acquired axially in the same anatomical location prescribed for the T2-weighted images to cover the entire spinal cord (C1-mid L1 levels). To mitigate motion induced artifacts, diffusion directional images were aligned with the reference image (b0) using a rigid body registration algorithm performed by in-house software developed in Matlab (MathWorks, Natick, Massachusetts). Diffusion tensor maps (FA and MD) and streamline deterministic tractography were then generated from the motion corrected DTI dataset. DTI and DTT parameters were calculated by using ROIs drawn to encapsulate the whole cord along the entire spinal cord by an independent board certified neuroradiologist. These indices then were compared between two age groups (age group A = 6-11 years (n = 11) and age group B = 12-16 years (n = 12)) based on similar standards and age definitions used for reporting spinal cord injury in the pediatric population. Standard least squared linear regression based on a restricted maximum likelihood (REML) method was used to evaluate the relationship between age and DTI and DTT parameters. Results An increase in FA (group A = 0.42 ± 0.097, group B = 0.49 ± 0.116), white matter tract density (group A = 368.01 ± 236.88, group B = 440.13 ± 245.24) and mean length of fiber tracts (group A = 48.16 ± 20.48 mm, group B = 60.28 ± 23.87 mm) and a decrease in MD (group A = 1.06 ± 0.23 × 10-3 mm2/s, group B = 0.82 ± 0.24 × 10-3 mm2/s) were observed with age along the entire spinal cord. Statistically significant increases have been shown in FA (p = 0.004, R2 = 0.57), tract density (p = 0.0004, R2 = 0.58), mean length of fiber tracts (p < 0.001, R2 = 0.5) and a significant decrease has been shown in MD (p = 0.002, R2 = 0.59) between group A and group B. Also, it has been shown DTI and DTT parameters vary along the spinal cord as a function of intervertebral disk and mid-vertebral body level. Conclusion This study provides an initial understanding of age related changes of DTI values as well as DTT metrics of the spinal cord. The results show significant differences in DTI and DTT parameters which may result from decreasing water content, myelination of fiber tracts, and the thickening diameter of fiber tracts during the maturation process. Consequently, when quantitative DTI and DTT of the spinal cord is undertaken in the pediatric population an age and level matched normative dataset should be used to accurately interpret the quantitative results.
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Affiliation(s)
- Mahdi Alizadeh
- Department of Neurosurgery, Thomas Jefferson University, Philadelphia, PA, United States; Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, PA, United States
| | - Joshua Fisher
- Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, PA, United States
| | - Sona Saksena
- Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, PA, United States
| | - Yusra Sultan
- Department of Biology, Drexel University, Philadelphia, PA, United States
| | - Chris J Conklin
- Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, PA, United States
| | - Devon M Middleton
- Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, PA, United States
| | - Laura Krisa
- Department of Occupational Therapy, Thomas Jefferson University, Philadelphia, PA, United States
| | - Jürgen Finsterbusch
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Adam E Flanders
- Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, PA, United States
| | - Scott H Faro
- Department of Radiology, Johns Hopkins University, Baltimore, MD, United States
| | - M J Mulcahey
- Department of Occupational Therapy, Thomas Jefferson University, Philadelphia, PA, United States
| | - Feroze B Mohamed
- Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, PA, United States.
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36
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Kafali SG, Çukur T, Saritas EU. Phase-correcting non-local means filtering for diffusion-weighted imaging of the spinal cord. Magn Reson Med 2018; 80:1020-1035. [PMID: 29427379 DOI: 10.1002/mrm.27105] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 12/26/2017] [Accepted: 01/02/2018] [Indexed: 11/09/2022]
Affiliation(s)
- Sevgi Gokce Kafali
- Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey.,National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey
| | - Tolga Çukur
- Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey.,National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey.,Neuroscience Program, Sabuncu Brain Research Center, Bilkent University, Ankara, Turkey
| | - Emine Ulku Saritas
- Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey.,National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey.,Neuroscience Program, Sabuncu Brain Research Center, Bilkent University, Ankara, Turkey
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37
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Alizadeh M, Fisher J, Saksena S, Sultan Y, Conklin CJ, Middleton DM, Finsterbusch J, Krisa L, Flanders AE, Faro SH, Mulcahey M, Mohamed FB. Reduced Field of View Diffusion Tensor Imaging and Fiber Tractography of the Pediatric Cervical and Thoracic Spinal Cord Injury. J Neurotrauma 2018; 35:452-460. [PMID: 29073810 PMCID: PMC5793949 DOI: 10.1089/neu.2017.5174] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The aim of this study is to assess the utility and effectiveness of diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) of the entire pediatric cervical and thoracic spinal cord toward discrimination of typically developing (TD) controls and subjects with spinal cord injury (SCI). A total of 43 pediatric subjects, including 23 TD subjects ranging in age from 6 to 16 years old and 20 subjects with SCI ranging in age from 7 to 16 years, were recruited and scanned using a 3.0 Tesla magnetic resonance scanner. Reduced field of view diffusion tensor images were acquired axially to cover the entire spinal cord across two slabs. For DTI analysis, motion correction was performed by coregistration of the diffusion-weighted images to the reference image (b0). Streamline deterministic tractography results were generated from the preprocessed data. DTI and DTT parameters of the whole cord, including fractional anisotropy (FA), mean diffusivity (MD), tract length, and tract density, were calculated, averaged across the whole spinal cord, and compared between the TD and SCI groups. Statistically significant decreases have been shown in FA (TD = 0.46 ± 0.11; SCI = 0.37 ± 0.09; p < 0.0001) and tract density (TD = 405.93 ± 243.84; SCI = 268.90 ± 270.34; p < 0.0001). However, the mean length of tracts and MD did not show significant differences. When investigating differences in DTI and DTT parameters above and below the injury site, it was shown that the FA and tract density in patients with cervical SCI decreased significantly in the thoracic region. An identical trend was observed in the cervical region for patients with thoracic SCI as well. When comparing TD and SCI subjects, FA and tract density were the most sensitive parameters in detecting functional changes of the spinal cord in chronic pediatric SCI. The results show that both DTI and DTT have the potential to be imaging biomarkers in the diagnosis of SCI.
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Affiliation(s)
- Mahdi Alizadeh
- Department of Neurosurgery, Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Joshua Fisher
- Department of Radiology, Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Sona Saksena
- Department of Radiology, Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Yusra Sultan
- Department of Biology, Drexel University, Philadelphia, Pennsylvania
| | - Chris J. Conklin
- Department of Radiology, Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Devon M. Middleton
- Department of Radiology, Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Jürgen Finsterbusch
- Institut für Systemische Neurowissenschaften, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Laura Krisa
- Department of Physical Therapy, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Adam E. Flanders
- Department of Radiology, Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Scott H. Faro
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland
| | - M.J. Mulcahey
- Department of Occupational Therapy, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Feroze B. Mohamed
- Department of Radiology, Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania
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38
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Russo M, Cousins MJ, Brooker C, Taylor N, Boesel T, Sullivan R, Poree L, Shariati NH, Hanson E, Parker J. Effective Relief of Pain and Associated Symptoms With Closed-Loop Spinal Cord Stimulation System: Preliminary Results of the Avalon Study. Neuromodulation 2017; 21:38-47. [PMID: 28922517 DOI: 10.1111/ner.12684] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 07/04/2017] [Accepted: 07/17/2017] [Indexed: 01/11/2023]
Abstract
OBJECTIVES Conventional spinal cord stimulation (SCS) delivers a fixed-input of energy into the dorsal column. Physiologic effects such as heartbeat, respiration, spinal cord movement, and history of stimulation can cause both the perceived intensity and recruitment of stimulation to increase or decrease, with clinical consequences. A new SCS system controls stimulation dose by measuring the recruitment of fibers in the dorsal column and by using the amplitude of the evoked compound action potentials (ECAPs) to maintain stimulation within an individualized therapeutic range. Safety and efficacy of this closed-loop system was evaluated through six-month postimplantation. MATERIALS AND METHODS Chronic pain subjects with back and/or leg pain who were successfully trialed received a permanent system (Evoke; Saluda Medical, Sydney, Australia). Ratings of pain (100-mm visual analogue scale [VAS] and Brief Pain Instrument [BPI]), quality of life (EuroQol instrument [EQ-5D-5L]), function (Oswestry Disability Index [ODI]), and sleep (Pittsburgh Sleep Quality Index [PSQI]) were collected at baseline and repeated three and six months after implantation. RESULTS Fifty-one subjects underwent a trial procedure; permanent implants were placed in 36 subjects. The proportion of subjects with ≥50% relief was 92.6% (back) and 91.3% (leg) at three months, and 85.7% (back) and 82.6% (leg) at six months. The proportion with ≥80% pain relief was 70.4% (back) and 56.5% (leg) at three months, and 64.3% (back) and 60.9% (leg) at six months. Statistically significant improvements in mean BPI, EQ-5D-5L, ODI, and PSQI were also observed at both time points. CONCLUSIONS The majority of subjects experienced profound pain relief at three and six months, providing preliminary evidence for the effectiveness of the closed-loop SCS system. The exact mechanism of action for these outcomes is still being explored, although one likely hypothesis holds that ECAP feedback control may minimize recruitment of Aβ nociceptors and Aδ fibers during daily use of SCS.
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Affiliation(s)
- Marc Russo
- Hunter Pain Clinic, Broadmeadow, New South Wales, Australia
| | - Michael J Cousins
- Pain Management Research Institute and Kolling Institute, University of Sydney at the Royal North Shore Hospital, St Leonards, NSW, Australia
| | - Charles Brooker
- Department of Pain Medicine, Royal North Shore Hospital, St Leonards, NSW, Australia.,Northern Clinical School, University of Sydney, Sydney, NSW, Australia
| | - Nathan Taylor
- Northern Private Pain Centre, St. Leonards, NSW, Australia
| | | | | | | | | | - Erin Hanson
- Saluda Medical Pty Ltd., Artarmon, NSW, Australia
| | - John Parker
- Saluda Medical Pty Ltd., Artarmon, NSW, Australia.,Graduate School of Biomedical Engineering, University of New South Wales, Kensington, NSW, Australia
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39
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Clinical utility for diffusion MRI sequence in emergency and inpatient spine protocols. Clin Imaging 2017; 45:37-50. [PMID: 28601735 DOI: 10.1016/j.clinimag.2017.05.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 05/10/2017] [Accepted: 05/30/2017] [Indexed: 11/20/2022]
Abstract
Diffusion imaging of the spine has the potential to change clinical management, but is challenging due to the small size of the cord and susceptibility artifacts from adjacent structures. Reduced field-of-view (rFOV) diffusion can improve image quality by decreasing the echo train length. Over the past 2 years, we have acquired a rFOV diffusion sequence for MRI spine protocols on most inpatients and emergency room patients. We provide selected imaging diagnoses to illustrate the utility of including diffusion spine MRI in clinical practice. Our experiences support using diffusion MRI to improve diagnostic certainty and facilitate prompt treatment or clinical management.
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40
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Harita S, Stroman PW. Confirmation of resting-state BOLD fluctuations in the human brainstem and spinal cord after identification and removal of physiological noise. Magn Reson Med 2017; 78:2149-2156. [DOI: 10.1002/mrm.26606] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 12/20/2016] [Accepted: 12/20/2016] [Indexed: 02/02/2023]
Affiliation(s)
- Shreyas Harita
- Centre for Neuroscience Studies; Queen's University; Kingston Canada
| | - Patrick W. Stroman
- Centre for Neuroscience Studies; Queen's University; Kingston Canada
- Department of Biomedical and Molecular Sciences; Queen's University; Kingston Canada
- Department of Physics; Queen's University; Kingston Canada
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41
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Eippert F, Kong Y, Winkler AM, Andersson JL, Finsterbusch J, Büchel C, Brooks JCW, Tracey I. Investigating resting-state functional connectivity in the cervical spinal cord at 3T. Neuroimage 2016; 147:589-601. [PMID: 28027960 PMCID: PMC5315056 DOI: 10.1016/j.neuroimage.2016.12.072] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Revised: 12/20/2016] [Accepted: 12/23/2016] [Indexed: 12/12/2022] Open
Abstract
The study of spontaneous fluctuations in the blood-oxygen-level-dependent (BOLD) signal has recently been extended from the brain to the spinal cord. Two ultra-high field functional magnetic resonance imaging (fMRI) studies in humans have provided evidence for reproducible resting-state connectivity between the dorsal horns as well as between the ventral horns, and a study in non-human primates has shown that these resting-state signals are impacted by spinal cord injury. As these studies were carried out at ultra-high field strengths using region-of-interest (ROI) based analyses, we investigated whether such resting-state signals could also be observed at the clinically more prevalent field strength of 3 T. In a reanalysis of a sample of 20 healthy human participants who underwent a resting-state fMRI acquisition of the cervical spinal cord, we were able to observe significant dorsal horn connectivity as well as ventral horn connectivity, but no consistent effects for connectivity between dorsal and ventral horns, thus replicating the human 7 T results. These effects were not only observable when averaging along the acquired length of the spinal cord, but also when we examined each of the acquired spinal segments separately, which showed similar patterns of connectivity. Finally, we investigated the robustness of these resting-state signals against variations in the analysis pipeline by varying the type of ROI creation, temporal filtering, nuisance regression and connectivity metric. We observed that – apart from the effects of band-pass filtering – ventral horn connectivity showed excellent robustness, whereas dorsal horn connectivity showed moderate robustness. Together, our results provide evidence that spinal cord resting-state connectivity is a robust and spatially consistent phenomenon that could be a valuable tool for investigating the effects of pathology, disease progression, and treatment response in neurological conditions with a spinal component, such as spinal cord injury.
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Affiliation(s)
- Falk Eippert
- Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.
| | - Yazhuo Kong
- Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK; Magnetic Resonance Imaging Research Centre, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
| | - Anderson M Winkler
- Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Jesper L Andersson
- Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Jürgen Finsterbusch
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christian Büchel
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | - Irene Tracey
- Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
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42
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Eippert F, Kong Y, Jenkinson M, Tracey I, Brooks JCW. Denoising spinal cord fMRI data: Approaches to acquisition and analysis. Neuroimage 2016; 154:255-266. [PMID: 27693613 DOI: 10.1016/j.neuroimage.2016.09.065] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 09/23/2016] [Accepted: 09/27/2016] [Indexed: 01/11/2023] Open
Abstract
Functional magnetic resonance imaging (fMRI) of the human spinal cord is a difficult endeavour due to the cord's small cross-sectional diameter, signal drop-out as well as image distortion due to magnetic field inhomogeneity, and the confounding influence of physiological noise from cardiac and respiratory sources. Nevertheless, there is great interest in spinal fMRI due to the spinal cord's role as the principal sensorimotor interface between the brain and the body and its involvement in a variety of sensory and motor pathologies. In this review, we give an overview of the various methods that have been used to address the technical challenges in spinal fMRI, with a focus on reducing the impact of physiological noise. We start out by describing acquisition methods that have been tailored to the special needs of spinal fMRI and aim to increase the signal-to-noise ratio and reduce distortion in obtained images. Following this, we concentrate on image processing and analysis approaches that address the detrimental effects of noise. While these include variations of standard pre-processing methods such as motion correction and spatial filtering, the main focus lies on denoising techniques that can be applied to task-based as well as resting-state data sets. We review both model-based approaches that rely on externally acquired respiratory and cardiac signals as well as data-driven approaches that estimate and correct for noise using the data themselves. We conclude with an outlook on techniques that have been successfully applied for noise reduction in brain imaging and whose use might be beneficial for fMRI of the human spinal cord.
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Affiliation(s)
- Falk Eippert
- Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Yazhuo Kong
- Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Mark Jenkinson
- Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Irene Tracey
- Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
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43
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Organization of the intrinsic functional network in the cervical spinal cord: A resting state functional MRI study. Neuroscience 2016; 336:30-38. [PMID: 27590264 DOI: 10.1016/j.neuroscience.2016.08.042] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Revised: 08/22/2016] [Accepted: 08/24/2016] [Indexed: 12/29/2022]
Abstract
Resting state functional magnetic resonance imaging (rsfMRI) has been extensively applied to investigate the organization of functional networks in the brain. As an essential part of the central nervous system (CNS), the spinal cord has not been well explored about its intrinsic functional network. In this study, we aim to thoroughly investigate the characteristics of the intrinsic functional network in the spinal cord using rsfMRI. Functional connectivity and graph theory analysis were employed to evaluate the organization of the functional network, including its topology and network communication properties. Furthermore, the reproducibility of rsfMRI analysis on the spinal cord was also examined by intra-class correlation (ICC). Comprehensive evaluation of the intrinsic functional organization presented a non-uniform distribution of topological characteristics of the functional network, in which the upper levels (C2 and C3 vertebral levels) of the cervical spinal cord showed high levels of connectivity. The present results revealed the significance of the upper cervical cord in the intrinsic functional network of the human cervical spinal cord. In addition, this study demonstrated the efficiency of the cervical spinal cord functional network and the reproducibility of rsfMRI analysis on the spinal cord was also confirmed. As knowledge expansion of intrinsic functional network from the brain to the spinal cord, this study shed light on the organization of the spinal cord functional network in both normal development and clinical disorders.
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44
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Reduced FOV diffusion tensor MR imaging and fiber tractography of pediatric cervical spinal cord injury. Spinal Cord 2016; 55:314-320. [DOI: 10.1038/sc.2016.121] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 05/31/2016] [Accepted: 07/01/2016] [Indexed: 12/14/2022]
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Hock A, Henning A. Motion correction and frequency stabilization for MRS of the human spinal cord. NMR IN BIOMEDICINE 2016; 29:490-498. [PMID: 26867133 DOI: 10.1002/nbm.3487] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 12/15/2015] [Accepted: 12/20/2015] [Indexed: 06/05/2023]
Abstract
Subject motion is challenging for MRS, because it can falsify results. For spinal cord MRS in particular, subject movement is critical, since even a small movement > 1 mm) can lead to a voxel shift out of the desired measurement region. Therefore, the identification of motion corrupted MRS scans is essential. In this investigation, MR navigators acquired simultaneously with the MRS data are used to identify a displacement of the spinal cord due to subject motion. It is shown that navigators are able to recognize substantial subject motion (>1 mm) without impairing the MRS measurement. In addition, navigators are easy to apply to the measurement, because no additional hardware and just a minor additional user effort are needed. Moreover, no additional scan time is required, because navigators can be applied in the deadtime of the MRS sequence. Furthermore, in this work, retrospective motion correction combined with frequency stabilization is presented by combining navigators with non-water-suppressed (1)H-MRS, resulting in an improved spectral quality of the spinal cord measurements.
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Affiliation(s)
- Andreas Hock
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
- Department of Psychiatry, Psychotherapy and Psychosomatics, Hospital of Psychiatry, University of Zurich, Zurich, Switzerland
| | - Anke Henning
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
- Max Plank Institute for Biological Cybernetics, Tuebingen, Germany
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Alexander MS, Kozyrev N, Bosma RL, Figley CR, Richards JS, Stroman PW. fMRI Localization of Spinal Cord Processing Underlying Female Sexual Arousal. JOURNAL OF SEX & MARITAL THERAPY 2016; 42:36-47. [PMID: 25635474 DOI: 10.1080/0092623x.2015.1010674] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Using functional magnetic resonance imaging, the authors aimed to determine the roles of the human spinal cord in mediating sexual responses in women. Functional magnetic resonance imaging of the entire lower thoracic, lumbar, and sacral spinal cord was performed using a sexual stimulation paradigm designed to elicit psychological and physical components of sexual arousal. Responses were measured in 9 healthy adult women during 3 consecutive conditions: (a) erotic audiovisual, (b) manual clitoral, and (c) audiovisual plus manual stimulation. Functional magnetic resonance imaging results in healthy subjects demonstrate that this method is sensitive for mapping sexual function in the spinal cord, and identify several key regions involved in human sexual response, including the intermediolateral cell column, the dorsal commissural nucleus, and the sacral parasympathetic nucleus. Using spinal functional magnetic resonance imaging, this study identified many of the spinal cord regions involved in female sexual responses. Results from audiovisual and manual clitoral stimulation correspond with previous data regarding lumbar and sacral neurologic changes during sexual arousal. This study provides the first characterization of neural activity in the human spinal cord underlying healthy female sexual responses and sets a foundation for future studies aimed at mapping changes that result from sexual dysfunction, spinal cord trauma or disease.
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Affiliation(s)
- Marcalee S Alexander
- a Department of Physical Medicine and Rehabilitation , University of Alabama at Birmingham , Birmingham , Alabama , USA
| | - Natalie Kozyrev
- b Centre for Neuroscience Studies , Queen's University , Kingston , Ontario , Canada
| | - Rachael L Bosma
- b Centre for Neuroscience Studies , Queen's University , Kingston , Ontario , Canada
| | - Chase R Figley
- b Centre for Neuroscience Studies , Queen's University , Kingston , Ontario , Canada
| | - J Scott Richards
- a Department of Physical Medicine and Rehabilitation , University of Alabama at Birmingham , Birmingham , Alabama , USA
| | - Patrick W Stroman
- b Centre for Neuroscience Studies , Queen's University , Kingston , Ontario , Canada
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Diffusion tensor imaging of the cervical spinal cord in children. Childs Nerv Syst 2015; 31:1239-45. [PMID: 26036198 DOI: 10.1007/s00381-015-2767-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 05/22/2015] [Indexed: 10/23/2022]
Abstract
PURPOSE Obtaining fast, reliable, high-resolution diffusion tensor imaging (DTI) of the pediatric cervical spinal cord (CSC) is challenging, given the multitude of technical limitations involved. Overcoming these limitations may further potentiate DTI as a valuable quantitative tool in evaluating the pediatric CSC. METHODS Sixteen patients (9 girls and 7 boys) with hypoxic brain injury, craniocervical junction malformations, and head trauma were included in this retrospective study. Region of interests were placed from C1-C2 through C7-T1 consecutively at the cervical intervertebral disc levels. DTI metrics were compared with a pediatric DTI database of healthy controls. Clinical background and outcomes were tabulated. RESULTS Patients with hypoxic brain injury, Chiari I and II malformations, and head trauma demonstrated lower fractional anisotropy values than that of healthy controls at certain cervical intervertebral disc levels. CONCLUSIONS DTI may be a promising modality for providing additional information beyond that of conventional magnetic resonance imaging in pediatric central nervous system disorders.
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Støverud KH, Alnæs M, Langtangen HP, Haughton V, Mardal KA. Poro-elastic modeling of Syringomyelia - a systematic study of the effects of pia mater, central canal, median fissure, white and gray matter on pressure wave propagation and fluid movement within the cervical spinal cord. Comput Methods Biomech Biomed Engin 2015; 19:686-98. [PMID: 26176823 DOI: 10.1080/10255842.2015.1058927] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Syringomyelia, fluid-filled cavities within the spinal cord, occurs frequently in association with a Chiari I malformation and produces some of its most severe neurological symptoms. The exact mechanism causing syringomyelia remains unknown. Since syringomyelia occurs frequently in association with obstructed cerebrospinal fluid (CSF) flow, it has been hypothesized that syrinx formation is mechanically driven. In this study we model the spinal cord tissue either as a poro-elastic medium or as a solid linear elastic medium, and simulate the propagation of pressure waves through an anatomically plausible 3D geometry, with boundary conditions based on in vivo CSF pressure measurements. Then various anatomic and tissue properties are modified, resulting in a total of 11 variations of the model that are compared. The results show that an open segment of the central canal and a stiff pia (relative to the cord) both increase the radial pressure gradients and enhance interstitial fluid flow in the central canal. The anterior median fissure, anisotropic permeability of the white matter, and Poisson ratio play minor roles.
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Affiliation(s)
- Karen H Støverud
- a Simula Research Laboratory , P.O. Box 134, 1325 Lysaker , Norway.,b Department of Informatics , University of Oslo , P.O. Box 1080 Blindern, 0316 Oslo , Norway
| | - Martin Alnæs
- a Simula Research Laboratory , P.O. Box 134, 1325 Lysaker , Norway
| | - Hans Petter Langtangen
- a Simula Research Laboratory , P.O. Box 134, 1325 Lysaker , Norway.,b Department of Informatics , University of Oslo , P.O. Box 1080 Blindern, 0316 Oslo , Norway
| | - Victor Haughton
- a Simula Research Laboratory , P.O. Box 134, 1325 Lysaker , Norway.,c Wisconsin Institutes of Medical Research , 1111 Highland Ave., Madison , WI 53705 , USA
| | - Kent-André Mardal
- a Simula Research Laboratory , P.O. Box 134, 1325 Lysaker , Norway.,d Department of Mathematics , University of Oslo , P.O. Box 1080 Blindern, 0316 Oslo , Norway
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Tseng CL, Sussman MS, Atenafu EG, Letourneau D, Ma L, Soliman H, Thibault I, Cho BCJ, Simeonov A, Yu E, Fehlings MG, Sahgal A. Magnetic resonance imaging assessment of spinal cord and cauda equina motion in supine patients with spinal metastases planned for spine stereotactic body radiation therapy. Int J Radiat Oncol Biol Phys 2015; 91:995-1002. [PMID: 25832691 DOI: 10.1016/j.ijrobp.2014.12.037] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2014] [Revised: 12/14/2014] [Accepted: 12/17/2014] [Indexed: 10/23/2022]
Abstract
PURPOSE To assess motion of the spinal cord and cauda equina, which are critical neural tissues (CNT), which is important when evaluating the planning organ-at-risk margin required for stereotactic body radiation therapy. METHODS AND MATERIALS We analyzed CNT motion in 65 patients with spinal metastases (11 cervical, 39 thoracic, and 24 lumbar spinal segments) in the supine position using dynamic axial and sagittal magnetic resonance imaging (dMRI, 3T Verio, Siemens) over a 137-second interval. Motion was segregated according to physiologic cardiorespiratory oscillatory motion (characterized by the average root mean square deviation) and random bulk shifts associated with gross patient motion (characterized by the range). Displacement was evaluated in the anteroposterior (AP), lateral (LR), and superior-inferior (SI) directions by use of a correlation coefficient template matching algorithm, with quantification of random motion measure error over 3 separate trials. Statistical significance was defined according to P<.05. RESULTS In the AP, LR, and SI directions, significant oscillatory motion was observed in 39.2%, 35.1%, and 10.8% of spinal segments, respectively, and significant bulk motions in all cases. The median oscillatory CNT motions in the AP, LR, and SI directions were 0.16 mm, 0.17 mm, and 0.44 mm, respectively, and the maximal statistically significant oscillatory motions were 0.39 mm, 0.41 mm, and 0.77 mm, respectively. The median bulk displacements in the AP, LR, and SI directions were 0.51 mm, 0.59 mm, and 0.66 mm, and the maximal statistically significant displacements were 2.21 mm, 2.87 mm, and 3.90 mm, respectively. In the AP, LR, and SI directions, bulk displacements were greater than 1.5 mm in 5.4%, 9.0%, and 14.9% of spinal segments, respectively. No significant differences in axial motion were observed according to cord level or cauda equina. CONCLUSIONS Oscillatory CNT motion was observed to be relatively minor. Our results support the importance of controlling bulk patient motion and the practice of applying a planning organ-at-risk margin.
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Affiliation(s)
- Chia-Lin Tseng
- Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada; Department of Radiation Oncology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada
| | - Marshall S Sussman
- Department of Medical Imaging, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Eshetu G Atenafu
- Department of Biostatistics, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Daniel Letourneau
- Department of Radiation Oncology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada
| | - Lijun Ma
- Department of Radiation Oncology, University of California San Francisco, San Francisco, California
| | - Hany Soliman
- Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
| | - Isabelle Thibault
- Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
| | - B C John Cho
- Department of Radiation Oncology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada
| | - Anna Simeonov
- Department of Radiation Oncology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada
| | - Eugene Yu
- Department of Medical Imaging, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Michael G Fehlings
- Department of Neurosurgery and Spine Program, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Arjun Sahgal
- Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada; Department of Radiation Oncology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada.
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Intrinsically organized resting state networks in the human spinal cord. Proc Natl Acad Sci U S A 2014; 111:18067-72. [PMID: 25472845 DOI: 10.1073/pnas.1414293111] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Spontaneous fluctuations in functional magnetic resonance imaging (fMRI) signals of the brain have repeatedly been observed when no task or external stimulation is present. These fluctuations likely reflect baseline neuronal activity of the brain and correspond to functionally relevant resting-state networks (RSN). It is not known however, whether intrinsically organized and spatially circumscribed RSNs also exist in the spinal cord, the brain's principal sensorimotor interface with the body. Here, we use recent advances in spinal fMRI methodology and independent component analysis to answer this question in healthy human volunteers. We identified spatially distinct RSNs in the human spinal cord that were clearly separated into dorsal and ventral components, mirroring the functional neuroanatomy of the spinal cord and likely reflecting sensory and motor processing. Interestingly, dorsal (sensory) RSNs were separated into right and left components, presumably related to ongoing hemibody processing of somatosensory information, whereas ventral (motor) RSNs were bilateral, possibly related to commissural interneuronal networks involved in central pattern generation. Importantly, all of these RSNs showed a restricted spatial extent along the spinal cord and likely conform to the spinal cord's functionally relevant segmental organization. Although the spatial and temporal properties of the dorsal and ventral RSNs were found to be significantly different, these networks showed significant interactions with each other at the segmental level. Together, our data demonstrate that intrinsically highly organized resting-state fluctuations exist in the human spinal cord and are thus a hallmark of the entire central nervous system.
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