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Büeler S, Freund P, Kessler TM, Liechti MD, David G. Improved inter-subject alignment of the lumbosacral cord for group-level in vivo gray and white matter assessments: A scan-rescan MRI study at 3T. PLoS One 2024; 19:e0301449. [PMID: 38626171 PMCID: PMC11020367 DOI: 10.1371/journal.pone.0301449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 03/15/2024] [Indexed: 04/18/2024] Open
Abstract
INTRODUCTION Magnetic resonance imaging (MRI) enables the investigation of pathological changes in gray and white matter at the lumbosacral enlargement (LSE) and conus medullaris (CM). However, conducting group-level analyses of MRI metrics in the lumbosacral spinal cord is challenging due to variability in CM length, lack of established image-based landmarks, and unknown scan-rescan reliability. This study aimed to improve inter-subject alignment of the lumbosacral cord to facilitate group-level analyses of MRI metrics. Additionally, we evaluated the scan-rescan reliability of MRI-based cross-sectional area (CSA) measurements and diffusion tensor imaging (DTI) metrics. METHODS Fifteen participants (10 healthy volunteers and 5 patients with spinal cord injury) underwent axial T2*-weighted and diffusion MRI at 3T. We assessed the reliability of spinal cord and gray matter-based landmarks for inter-subject alignment of the lumbosacral cord, the inter-subject variability of MRI metrics before and after adjusting for the CM length, the intra- and inter-rater reliability of CSA measurements, and the scan-rescan reliability of CSA measurements and DTI metrics. RESULTS The slice with the largest gray matter CSA as an LSE landmark exhibited the highest reliability, both within and across raters. Adjusting for the CM length greatly reduced the inter-subject variability of MRI metrics. The intra-rater, inter-rater, and scan-rescan reliability of MRI metrics were the highest at and around the LSE (scan-rescan coefficient of variation <3% for CSA measurements and <7% for DTI metrics within the white matter) and decreased considerably caudal to it. CONCLUSIONS To facilitate group-level analyses, we recommend using the slice with the largest gray matter CSA as a reliable LSE landmark, along with an adjustment for the CM length. We also stress the significance of the anatomical location within the lumbosacral cord in relation to the reliability of MRI metrics. The scan-rescan reliability values serve as valuable guides for power and sample size calculations in future longitudinal studies.
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Affiliation(s)
- Silvan Büeler
- Department of Neuro-Urology, Balgrist University Hospital, University of Zürich, Zürich, Switzerland
| | - Patrick Freund
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zürich, Zürich, Switzerland
- Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
- UCL Queen Square Institute of Neurology, Wellcome Trust Centre for Human Neuroimaging, University College London, London, United Kingdom
| | - Thomas M. Kessler
- Department of Neuro-Urology, Balgrist University Hospital, University of Zürich, Zürich, Switzerland
| | - Martina D. Liechti
- Department of Neuro-Urology, Balgrist University Hospital, University of Zürich, Zürich, Switzerland
| | - Gergely David
- Department of Neuro-Urology, Balgrist University Hospital, University of Zürich, Zürich, Switzerland
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zürich, Zürich, Switzerland
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Clark IA, Maguire EA. Release of cognitive and multimodal MRI data including real-world tasks and hippocampal subfield segmentations. Sci Data 2023; 10:540. [PMID: 37587129 PMCID: PMC10432478 DOI: 10.1038/s41597-023-02449-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 08/07/2023] [Indexed: 08/18/2023] Open
Abstract
We share data from N = 217 healthy adults (mean age 29 years, range 20-41; 109 females, 108 males) who underwent extensive cognitive assessment and neuroimaging to examine the neural basis of individual differences, with a particular focus on a brain structure called the hippocampus. Cognitive data were collected using a wide array of questionnaires, naturalistic tests that examined imagination, autobiographical memory recall and spatial navigation, traditional laboratory-based tests such as recalling word pairs, and comprehensive characterisation of the strategies used to perform the cognitive tests. 3 Tesla MRI data were also acquired and include multi-parameter mapping to examine tissue microstructure, diffusion-weighted MRI, T2-weighted high-resolution partial volume structural MRI scans (with the masks of hippocampal subfields manually segmented from these scans), whole brain resting state functional MRI scans and partial volume high resolution resting state functional MRI scans. This rich dataset will be of value to cognitive and clinical neuroscientists researching individual differences, real-world cognition, brain-behaviour associations, hippocampal subfields and more. All data are freely available on Dryad.
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Affiliation(s)
- Ian A Clark
- Wellcome Centre for Human Neuroimaging, Department of Imaging Neuroscience, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Eleanor A Maguire
- Wellcome Centre for Human Neuroimaging, Department of Imaging Neuroscience, UCL Queen Square Institute of Neurology, University College London, London, UK.
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Milotta G, Corbin N, Lambert C, Lutti A, Mohammadi S, Callaghan MF. Mitigating the impact of flip angle and orientation dependence in single compartment R2* estimates via 2-pool modeling. Magn Reson Med 2023; 89:128-143. [PMID: 36161672 PMCID: PMC9827921 DOI: 10.1002/mrm.29428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 07/08/2022] [Accepted: 08/08/2022] [Indexed: 01/12/2023]
Abstract
PURPOSE The effective transverse relaxation rate (R 2 * $$ {\mathrm{R}}_2^{\ast } $$ ) is influenced by biological features that make it a useful means of probing brain microstructure. However, confounding factors such as dependence on flip angle (α) and fiber orientation with respect to the main field (θ $$ \uptheta $$ ) complicate interpretation. The α- andθ $$ \uptheta $$ -dependence stem from the existence of multiple sub-voxel micro-environments (e.g., myelin and non-myelin water compartments). Ordinarily, it is challenging to quantify these sub-compartments; therefore, neuroscientific studies commonly make the simplifying assumption of a mono-exponential decay obtaining a singleR 2 * $$ {\mathrm{R}}_2^{\ast } $$ estimate per voxel. In this work, we investigated how the multi-compartment nature of tissue microstructure affects single compartmentR 2 * $$ {\mathrm{R}}_2^{\ast } $$ estimates. METHODS We used 2-pool (myelin and non-myelin water) simulations to characterize the bias in single compartmentR 2 * $$ {\mathrm{R}}_2^{\ast } $$ estimates. Based on our numeric observations, we introduced a linear model that partitionsR 2 * $$ {\mathrm{R}}_2^{\ast } $$ into α-dependent and α-independent components and validated this in vivo at 7T. We investigated the dependence of both components on the sub-compartment properties and assessed their robustness, orientation dependence, and reproducibility empirically. RESULTS R 2 * $$ {\mathrm{R}}_2^{\ast } $$ increased with myelin water fraction and residency time leading to a linear dependence on α. We observed excellent agreement between our numeric and empirical results. Furthermore, the α-independent component of the proposed linear model was robust to the choice of α and reduced dependence on fiber orientation, although it suffered from marginally higher noise sensitivity. CONCLUSION We have demonstrated and validated a simple approach that mitigates flip angle and orientation biases in single-compartmentR 2 * $$ {\mathrm{R}}_2^{\ast } $$ estimates.
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Affiliation(s)
- Giorgia Milotta
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of NeurologyUniversity College London
LondonUnited Kingdom
| | - Nadège Corbin
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of NeurologyUniversity College London
LondonUnited Kingdom
- Centre de Résonance Magnétique des Systèmes Biologiques, UMR5536CNRS/University BordeauxBordeauxFrance
| | - Christian Lambert
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of NeurologyUniversity College London
LondonUnited Kingdom
| | - Antoine Lutti
- Laboratory for Research in Neuroimaging, Department for Clinical NeuroscienceLausanne University Hospital and University of LausanneLausanneSwitzerland
| | - Siawoosh Mohammadi
- Department of Systems NeurosciencesUniversity Medical Center Hamburg‐EppendorfHamburgGermany
- Department of NeurophysicsMax Planck Institute for Human Cognitive and Brain SciencesLeipzigGermany
| | - Martina F. Callaghan
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of NeurologyUniversity College London
LondonUnited Kingdom
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Clark IA, Mohammadi S, Callaghan MF, Maguire EA. Conduction velocity along a key white matter tract is associated with autobiographical memory recall ability. eLife 2022; 11:79303. [PMID: 36166372 PMCID: PMC9514844 DOI: 10.7554/elife.79303] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 09/12/2022] [Indexed: 12/01/2022] Open
Abstract
Conduction velocity is the speed at which electrical signals travel along axons and is a crucial determinant of neural communication. Inferences about conduction velocity can now be made in vivo in humans using a measure called the magnetic resonance (MR) g-ratio. This is the ratio of the inner axon diameter relative to that of the axon plus the myelin sheath that encases it. Here, in the first application to cognition, we found that variations in MR g-ratio, and by inference conduction velocity, of the parahippocampal cingulum bundle were associated with autobiographical memory recall ability in 217 healthy adults. This tract connects the hippocampus with a range of other brain areas. We further observed that the association seemed to be with inner axon diameter rather than myelin content. The extent to which neurites were coherently organised within the parahippocampal cingulum bundle was also linked with autobiographical memory recall ability. Moreover, these findings were specific to autobiographical memory recall and were not apparent for laboratory-based memory tests. Our results offer a new perspective on individual differences in autobiographical memory recall ability, highlighting the possible influence of specific white matter microstructure features on conduction velocity when recalling detailed memories of real-life past experiences.
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Affiliation(s)
- Ian A Clark
- Wellcome Centre for Human Neuroimaging, Department of Imaging Neuroscience, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Siawoosh Mohammadi
- Institute of Systems Neuroscience, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - Martina F Callaghan
- Wellcome Centre for Human Neuroimaging, Department of Imaging Neuroscience, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Eleanor A Maguire
- Wellcome Centre for Human Neuroimaging, Department of Imaging Neuroscience, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
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Dauleac C, Frindel C, Pélissou-Guyotat I, Nicolas C, Yeh FC, Fernandez-Miranda J, Cotton F, Jacquesson T. Full cervical cord tractography: A new method for clinical use. Front Neuroanat 2022; 16:993464. [PMID: 36237419 PMCID: PMC9550930 DOI: 10.3389/fnana.2022.993464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 09/06/2022] [Indexed: 12/02/2022] Open
Abstract
Despite recent improvements in diffusion-weighted imaging, spinal cord tractography is not used in routine clinical practice because of difficulties in reconstructing tractograms, with a pertinent tri-dimensional-rendering, in a long post-processing time. We propose a new full tractography approach to the cervical spinal cord without extensive manual filtering or multiple regions of interest seeding that could help neurosurgeons manage various spinal cord disorders. Four healthy volunteers and two patients with either cervical intramedullary tumors or spinal cord injuries were included. Diffusion-weighted images of the cervical spinal cord were acquired using a Philips 3 Tesla machine, 32 diffusion directions, 1,000 s/mm2b-value, 2 × 2 × 2 mm voxel size, reduced field-of-view (ZOOM), with two opposing phase-encoding directions. Distortion corrections were then achieved using the FSL software package, and tracking of the full cervical spinal cord was performed using the DSI Studio software (quantitative anisotropy-based deterministic algorithm). A unique region of avoidance was used to exclude everything that is not of the nervous system. Fiber tracking parameters used adaptative fractional anisotropy from 0.015 to 0.045, fiber length from 10 to 1,000 mm, and angular threshold of 90°. In all participants, a full cervical cord tractography was performed from the medulla to the C7 spine level. On a ventral view, the junction between the medulla and spinal cord was identified with its pyramidal bulging, and by an invagination corresponding to the median ventral sulcus. On a dorsal view, the fourth ventricle—superior, middle, and inferior cerebellar peduncles—was seen, as well as its floor and the obex; and gracile and cuneate tracts were recognized on each side of the dorsal median sulcus. In the case of the intramedullary tumor or spinal cord injury, the spinal tracts were seen to be displaced, and this helped to adjust the neurosurgical strategy. This new full tractography approach simplifies the tractography pipeline and provides a reliable 3D-rendering of the spinal cord that could help to adjust the neurosurgical strategy.
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Affiliation(s)
- Corentin Dauleac
- Service de Neurochirurgie, Hôpital neurologique et neurochirurgical Pierre Wertheimer, Hospices Civils de Lyon, Lyon, France
- Laboratoire CREATIS, CNRS UMR5220, Inserm U1206, INSA-Lyon, Villeurbanne, France
- Université de Lyon I, Lyon, France
- *Correspondence: Corentin Dauleac
| | - Carole Frindel
- Laboratoire CREATIS, CNRS UMR5220, Inserm U1206, INSA-Lyon, Villeurbanne, France
- Université de Lyon I, Lyon, France
| | - Isabelle Pélissou-Guyotat
- Service de Neurochirurgie, Hôpital neurologique et neurochirurgical Pierre Wertheimer, Hospices Civils de Lyon, Lyon, France
| | - Célia Nicolas
- Hospices Civils de Lyon, Centre Hospitalier de Lyon Sud, Service de Radiologie, Lyon, France
| | - Fang-Cheng Yeh
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, United States
| | - Juan Fernandez-Miranda
- Department of Neurosurgery, Stanford University Medical Center, Stanford, CA, United States
| | - François Cotton
- Laboratoire CREATIS, CNRS UMR5220, Inserm U1206, INSA-Lyon, Villeurbanne, France
- Université de Lyon I, Lyon, France
- Hospices Civils de Lyon, Centre Hospitalier de Lyon Sud, Service de Radiologie, Lyon, France
| | - Timothée Jacquesson
- Service de Neurochirurgie, Hôpital neurologique et neurochirurgical Pierre Wertheimer, Hospices Civils de Lyon, Lyon, France
- Laboratoire CREATIS, CNRS UMR5220, Inserm U1206, INSA-Lyon, Villeurbanne, France
- Université de Lyon I, Lyon, France
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David G, Vallotton K, Hupp M, Curt A, Freund P, Seif M. Extent of cord pathology in the lumbosacral enlargement in non-traumatic versus traumatic spinal cord injury. J Neurotrauma 2022; 39:639-650. [PMID: 35018824 DOI: 10.1089/neu.2021.0389] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
This study compares remote neurodegenerative changes caudal to a cervical injury in degenerative cervical myelopathy (DCM) (i.e., non-traumatic) and incomplete traumatic spinal cord injury (tSCI) patients, using MRI-based tissue area measurements and diffusion tensor imaging (DTI). Eighteen mild to moderate DCM patients with sensory impairments (mJOA score: 16.2±1.9), 14 incomplete tetraplegic tSCI patients (AIS C&D), and 20 healthy controls were recruited. All participants received DTI and T2*-weighted scans in the lumbosacral enlargement (caudal to injury) and at C2/C3 (rostral to injury). MRI readouts included DTI metrics in the white matter (WM) columns and cross-sectional WM and gray matter area. One-way ANOVA with Tukey's post-hoc comparison (p<0.05) was used to assess group differences. In the lumbosacral enlargement, compared to DCM, tSCI patients exhibited decreased fractional anisotropy in the lateral (tSCI vs. DCM, -11.9%, p=0.007) and ventral WM column (-8.0%, p=0.021), and showed trend toward lower values in the dorsal column (-8.9%, p=0.068). At C2/C3, compared to controls, fractional anisotropy was lower in both groups in the dorsal (DCM vs. controls, -7.9%, p=0.024; tSCI vs. controls, -10.0%, p=0.007) and in the lateral column (DCM: -6.2%, p=0.039; tSCI: -13.3%, p<0.001), while tSCI patients had lower fractional anisotropy than DCM patients in the lateral column (-7.6%, p=0.029). WM areas were not different between patient groups but were lower compared to controls in the lumbosacral enlargement (DCM: -16.9%, p<0.001; tSCI, -10.5%, p=0.043) and at C2/C3 (DCM: -16.0%, p<0.001; tSCI: -18.1%, p<0.001). In conclusion, mild to moderate DCM and incomplete tSCI lead to similar degree of degeneration of the dorsal and lateral columns at C2/C3, but tSCI results in more widespread white matter damage in the lumbosacral enlargement. These remote changes are likely to contribute to the patients' impairment and recovery. DTI is a sensitive tool to assess remote pathological changes in DCM and tSCI patients.
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Affiliation(s)
- Gergely David
- University of Zurich, Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland.,University Medical Center Hamburg-Eppendorf, 37734, Department of Systems Neuroscience, Hamburg, Germany;
| | - Kevin Vallotton
- University of Zurich, Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland;
| | - Markus Hupp
- University of Zurich, 27217, Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland;
| | - Armin Curt
- University of Zurich, 27217, Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland;
| | - Patrick Freund
- University of Zurich, 27217, Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland.,UCL Institute of Neurology, 61554, Department of Brain Repair and Rehabilitation, London, United Kingdom of Great Britain and Northern Ireland.,UCL Institute of Neurology, 61554, Wellcome Trust Centre for Neuroimaging, London, United Kingdom of Great Britain and Northern Ireland.,Max Planck Institute for Human Cognitive and Brain Sciences, 27184, Department of Neurophysics, Leipzig, Germany;
| | - Maryam Seif
- University of Zurich, 27217, Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland.,Max Planck Institute for Human Cognitive and Brain Sciences, 27184, Leipzig, Department of Neurophysics, Germany;
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David G, Pfyffer D, Vallotton K, Pfender N, Thompson A, Weiskopf N, Mohammadi S, Curt A, Freund P. Longitudinal changes of spinal cord grey and white matter following spinal cord injury. J Neurol Neurosurg Psychiatry 2021; 92:1222-1230. [PMID: 34341143 PMCID: PMC8522459 DOI: 10.1136/jnnp-2021-326337] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 06/09/2021] [Indexed: 11/21/2022]
Abstract
OBJECTIVES Traumatic and non-traumatic spinal cord injury produce neurodegeneration across the entire neuraxis. However, the spatiotemporal dynamics of spinal cord grey and white matter neurodegeneration above and below the injury is understudied. METHODS We acquired longitudinal data from 13 traumatic and 3 non-traumatic spinal cord injury patients (8-8 cervical and thoracic cord injuries) within 1.5 years after injury and 10 healthy controls over the same period. The protocol encompassed structural and diffusion-weighted MRI rostral (C2/C3) and caudal (lumbar enlargement) to the injury level to track tissue-specific neurodegeneration. Regression models assessed group differences in the temporal evolution of tissue-specific changes and associations with clinical outcomes. RESULTS At 2 months post-injury, white matter area was decreased by 8.5% and grey matter by 15.9% in the lumbar enlargement, while at C2/C3 only white matter was decreased (-9.7%). Patients had decreased cervical fractional anisotropy (FA: -11.3%) and increased radial diffusivity (+20.5%) in the dorsal column, while FA was lower in the lateral (-10.3%) and ventral columns (-9.7%) of the lumbar enlargement. White matter decreased by 0.34% and 0.35% per month at C2/C3 and lumbar enlargement, respectively, and grey matter decreased at C2/C3 by 0.70% per month. CONCLUSIONS This study describes the spatiotemporal dynamics of tissue-specific spinal cord neurodegeneration above and below a spinal cord injury. While above the injury, grey matter atrophy lagged initially behind white matter neurodegeneration, in the lumbar enlargement these processes progressed in parallel. Tracking trajectories of tissue-specific neurodegeneration provides valuable assessment tools for monitoring recovery and treatment effects.
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Affiliation(s)
- Gergely David
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Dario Pfyffer
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Kevin Vallotton
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Nikolai Pfender
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Alan Thompson
- Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, London, UK
| | - Nikolaus Weiskopf
- Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.,Felix Bloch Institute for Solid State Physics, Faculty of Physics and Earth Sciences, Leipzig University, Leipzig, Germany
| | - Siawoosh Mohammadi
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Armin Curt
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Patrick Freund
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland .,Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, London, UK.,Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.,Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, London, UK
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Clark IA, Callaghan MF, Weiskopf N, Maguire EA, Mohammadi S. Reducing Susceptibility Distortion Related Image Blurring in Diffusion MRI EPI Data. Front Neurosci 2021; 15:706473. [PMID: 34421526 PMCID: PMC8376472 DOI: 10.3389/fnins.2021.706473] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 07/09/2021] [Indexed: 11/21/2022] Open
Abstract
Diffusion magnetic resonance imaging (MRI) is an increasingly popular technique in basic and clinical neuroscience. One promising application is to combine diffusion MRI with myelin maps from complementary MRI techniques such as multi-parameter mapping (MPM) to produce g-ratio maps that represent the relative myelination of axons and predict their conduction velocity. Statistical Parametric Mapping (SPM) can process both diffusion data and MPMs, making SPM the only widely accessible software that contains all the processing steps required to perform group analyses of g-ratio data in a common space. However, limitations have been identified in its method for reducing susceptibility-related distortion in diffusion data. More generally, susceptibility-related image distortion is often corrected by combining reverse phase-encoded images (blip-up and blip-down) using the arithmetic mean (AM), however, this can lead to blurred images. In this study we sought to (1) improve the susceptibility-related distortion correction for diffusion MRI data in SPM; (2) deploy an alternative approach to the AM to reduce image blurring in diffusion MRI data when combining blip-up and blip-down EPI data after susceptibility-related distortion correction; and (3) assess the benefits of these changes for g-ratio mapping. We found that the new processing pipeline, called consecutive Hyperelastic Susceptibility Artefact Correction (HySCO) improved distortion correction when compared to the standard approach in the ACID toolbox for SPM. Moreover, using a weighted average (WA) method to combine the distortion corrected data from each phase-encoding polarity achieved greater overlap of diffusion and more anatomically faithful structural white matter probability maps derived from minimally distorted multi-parameter maps as compared to the AM. Third, we showed that the consecutive HySCO WA performed better than the AM method when combined with multi-parameter maps to perform g-ratio mapping. These improvements mean that researchers can conveniently access a wide range of diffusion-related analysis methods within one framework because they are now available within the open-source ACID toolbox as part of SPM, which can be easily combined with other SPM toolboxes, such as the hMRI toolbox, to facilitate computation of myelin biomarkers that are necessary for g-ratio mapping.
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Affiliation(s)
- Ian A. Clark
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Martina F. Callaghan
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Nikolaus Weiskopf
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
- Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
- Felix Bloch Institute for Solid State Physics, Faculty of Physics and Earth Sciences, Leipzig University, Leipzig, Germany
| | - Eleanor A. Maguire
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Siawoosh Mohammadi
- Institute of Systems Neuroscience, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
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9
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Vallotton K, David G, Hupp M, Pfender N, Cohen-Adad J, Fehlings MG, Samson RS, Wheeler-Kingshott CAMG, Curt A, Freund P, Seif M. Tracking White and Gray Matter Degeneration along the Spinal Cord Axis in Degenerative Cervical Myelopathy. J Neurotrauma 2021; 38:2978-2987. [PMID: 34238034 DOI: 10.1089/neu.2021.0148] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
This study aims to determine tissue-specific neurodegeneration across the spinal cord in patients with mild-moderate degenerative cervical myelopathy (DCM). Twenty-four mild-moderate DCM and 24 healthy subjects were recruited. In patients, a T2-weighted scan was acquired at the compression site, whereas in all participants a T2*-weighted and diffusion-weighted scan was acquired at the cervical level (C2-C3) and in the lumbar enlargement (i.e., rostral and caudal to the site of compression). We quantified intramedullary signal changes, maximal canal and cord compression, white (WM) and gray matter (GM) atrophy, and microstructural indices from diffusion-weighted scans. All patients underwent clinical (modified Japanese Orthopaedic Association; mJOA) and electrophysiological assessments. Regression analysis assessed associations between magnetic resonance imaging (MRI) readouts and electrophysiological and clinical outcomes. Twenty patients were classified with mild and 4 with moderate DCM using the mJOA scale. The most frequent site of compression was at the C5-C6 level, with maximum cord compression of 38.73% ± 11.57%. Ten patients showed imaging evidence of cervical myelopathy. In the cervical cord, WM and GM atrophy and WM microstructural changes were evident, whereas in the lumbar cord only WM showed atrophy and microstructural changes. Remote cervical cord WM microstructural changes were pronounced in patients with radiological myelopathy and associated with impaired electrophysiology. Lumbar cord WM atrophy was associated with lower limb sensory impairments. In conclusion, tissue-specific neurodegeneration revealed by quantitative MRI is already apparent across the spinal cord in mild-moderate DCM before the onset of severe clinical impairments. WM microstructural changes are particularly sensitive to remote pathologically and clinically eloquent changes in DCM.
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Affiliation(s)
- Kevin Vallotton
- Spinal Cord Injury Center Balgrist, University of Zurich, Zurich, Switzerland
| | - Gergely David
- Spinal Cord Injury Center Balgrist, University of Zurich, Zurich, Switzerland
| | - Markus Hupp
- Spinal Cord Injury Center Balgrist, University of Zurich, Zurich, Switzerland
| | - Nikolai Pfender
- Spinal Cord Injury Center Balgrist, University of Zurich, Zurich, Switzerland
| | - Julien Cohen-Adad
- NeuroPoly Lab, Institute of Biomedical Engineering, Polytechnique Montreal, Montreal, Quebec, Canada.,Functional Neuroimaging Unit, CRIUGM, University of Montreal, Montreal, Quebec, Canada.,Mila-Quebec AI Institute, Montreal, Quebec, Canada
| | - Michael G Fehlings
- Department of Surgery and Spine Program, University of Toronto and Toronto Western Hospital, Toronto, Ontario, Canada
| | - Rebecca S Samson
- NMR Research Unit, Queen Square MS Centre, UCL Queen Square Institute of Neurology, Faculty of Brain Sciences, London, United Kingdom
| | - Claudia A M Gandini Wheeler-Kingshott
- NMR Research Unit, Queen Square MS Centre, UCL Queen Square Institute of Neurology, Faculty of Brain Sciences, London, United Kingdom.,Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy.,Brain Connectivity Centre, IRCCS Mondino Foundation, Pavia, Italy
| | - Armin Curt
- Spinal Cord Injury Center Balgrist, University of Zurich, Zurich, Switzerland
| | - Patrick Freund
- Spinal Cord Injury Center Balgrist, University of Zurich, Zurich, Switzerland.,Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.,Department of Brain Repair and Rehabilitation, Institute of Neurology, University College London, London, United Kingdom.,Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, London, United Kingdom
| | - Maryam Seif
- Spinal Cord Injury Center Balgrist, University of Zurich, Zurich, Switzerland.,Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
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10
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High-fidelity diffusion tensor imaging of the cervical spinal cord using point-spread-function encoded EPI. Neuroimage 2021; 236:118043. [PMID: 33857617 DOI: 10.1016/j.neuroimage.2021.118043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 03/16/2021] [Accepted: 03/31/2021] [Indexed: 01/21/2023] Open
Abstract
Diffusion tensor imaging (DTI) of the spinal cord is technically challenging due to the size of its structure and susceptibility-induced field inhomogeneity, which impedes clinical applications. This study aimed to achieve high-fidelity spinal cord DTI with reasonable SNR and practical acquisition efficiency. Particularly, a distortion-free multi-shot EPI technique, namely point-spread-function encoded EPI (PSF-EPI), was adopted for diffusion imaging of the cervical spinal cord (CSC). The shot number can be reduced to six for sagittal scans through titled-CAIPI acceleration and partial Fourier undersampling, consequently rendering this technique beneficial in clinics. Fifteen healthy volunteers and seven patients with metallic implants underwent sagittal scans using tilted-CAIPI PSF-EPI at 3T. Unsuppressed fat signals were further removed by retrospective water/fat separation using the intrinsic chemical-shift encoded signals. Compared with multi-shot interleaved EPI method, highly accelerated PSF-EPI method provided evidently improved distortion reduction and higher consistency with anatomical references even with metallic implants. Additionally, axial DTI scans using PSF-EPI were also evaluated quantitatively, and the measured DTI metrics are similar to those obtained from the zonal oblique multi-slice EPI (ZOOM-EPI) method and reported values. The high anatomical consistency, practical scan time and quantitative reliability indicate PSF-EPI's clinical potential for CSC diffusion imaging.
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11
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Childhood socioeconomic status is associated with psychometric intelligence and microstructural brain development. Commun Biol 2021; 4:470. [PMID: 33927305 PMCID: PMC8084976 DOI: 10.1038/s42003-021-01974-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 03/10/2021] [Indexed: 02/02/2023] Open
Abstract
Childhood socioeconomic status is robustly associated with various children's cognitive factors and neural mechanisms. Here we show the association of childhood socioeconomic status with psychometric intelligence and mean diffusivity and fractional anisotropy using diffusion tensor imaging at the baseline experiment (N = 285) and longitudinal changes in these metrics after 3.0 ± 0.3 years (N = 223) in a large sample of normal Japanese children (mean age = 11.2 ± 3.1 years). After correcting for confounding factors, cross-sectional and longitudinal analyses show that higher childhood socioeconomic status is associated with greater baseline and baseline to follow-up increase of psychometric intelligence and mean diffusivity in areas around the bilateral fusiform gyrus. These results demonstrate that higher socioeconomic status is associated with higher psychometric intelligence measures and altered microstructural properties in the fusiform gyrus which plays a key role in reading and letter recognition and further augmentation of such tendencies during development. Definitive conclusions regarding the causality of these relationships requires intervention and physiological studies. However, the current findings should be considered when developing and revising policies regarding education.
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12
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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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13
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Irimia A, Van Horn JD. Mapping the rest of the human connectome: Atlasing the spinal cord and peripheral nervous system. Neuroimage 2021; 225:117478. [PMID: 33160086 PMCID: PMC8485987 DOI: 10.1016/j.neuroimage.2020.117478] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 09/15/2020] [Accepted: 10/13/2020] [Indexed: 12/13/2022] Open
Abstract
The emergence of diffusion, structural, and functional neuroimaging methods has enabled major multi-site efforts to map the human connectome, which has heretofore been defined as containing all neural connections in the central nervous system (CNS). However, these efforts are not structured to examine the richness and complexity of the peripheral nervous system (PNS), which arguably forms the (neglected) rest of the connectome. Despite increasing interest in an atlas of the spinal cord (SC) and PNS which is simultaneously stereotactic, interactive, electronically dissectible, scalable, population-based and deformable, little attention has thus far been devoted to this task of critical importance. Nevertheless, the atlasing of these complete neural structures is essential for neurosurgical planning, neurological localization, and for mapping those components of the human connectome located outside of the CNS. Here we recommend a modification to the definition of the human connectome to include the SC and PNS, and argue for the creation of an inclusive atlas to complement current efforts to map the brain's human connectome, to enhance clinical education, and to assist progress in neuroscience research. In addition to providing a critical overview of existing neuroimaging techniques, image processing methodologies and algorithmic advances which can be combined for the creation of a full connectome atlas, we outline a blueprint for ultimately mapping the entire human nervous system and, thereby, for filling a critical gap in our scientific knowledge of neural connectivity.
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Affiliation(s)
- Andrei Irimia
- Ethel Percy Andrus Gerontology Center, Leonard Davis School of Gerontology, University of Southern California, 3715 McClintock Avenue, Los Angeles CA 90089, United States; Corwin D. Denney Research Center, Department of Biomedical Engineering, Viterbi School of Engineering, University of Southern California, 1042 Downey Way, Los Angeles, CA 90089, United States.
| | - John Darrell Van Horn
- Department of Psychology, University of Virginia, 485 McCormick Road, Gilmer Hall, Room 102, Charlottesville, Virginia 22903, United States; School of Data Science, University of Virginia, Dell 1, Charlottesville, Virginia 22903, United States.
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14
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Tinnermann A, Büchel C, Cohen-Adad J. Cortico-spinal imaging to study pain. Neuroimage 2020; 224:117439. [PMID: 33039624 DOI: 10.1016/j.neuroimage.2020.117439] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 09/21/2020] [Accepted: 10/01/2020] [Indexed: 12/15/2022] Open
Abstract
Functional magnetic resonance imaging of the brain has helped to reveal mechanisms of pain perception in health and disease. Recently, imaging approaches have been developed that allow recording neural activity simultaneously in the brain and in the spinal cord. These approaches offer the possibility to examine pain perception in the entire central pain system and in addition, to investigate cortico-spinal interactions during pain processing. Although cortico-spinal imaging is a promising technique, it bears challenges concerning data acquisition and data analysis strategies. In this review, we discuss studies that applied simultaneous imaging of the brain and spinal cord to explore central pain processing. Furthermore, we describe different MR-related acquisition techniques, summarize advantages and disadvantages of approaches that have been implemented so far and present software that has been specifically developed for the analysis of spinal fMRI data to address challenges of spinal data analysis.
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Affiliation(s)
- Alexandra Tinnermann
- Department for Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; Max Planck School of Cognition, Leipzig, Germany.
| | - Christian Büchel
- Department for Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; Max Planck School of Cognition, Leipzig, Germany
| | - Julien Cohen-Adad
- NeuroPoly Lab, Institute of Biomedical Engineering, Polytechnique Montreal, Montreal, Quebec, Canada; Functional Neuroimaging Unit, CRIUGM, Université de Montréal, Montreal, Quebec, Canada.
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15
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Noguerol TM, Barousse R, Amrhein TJ, Royuela-del-Val J, Montesinos P, Luna A. Optimizing Diffusion-Tensor Imaging Acquisition for Spinal Cord Assessment: Physical Basis and Technical Adjustments. Radiographics 2020; 40:403-427. [DOI: 10.1148/rg.2020190058] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Teodoro Martín Noguerol
- From the MRI Section, Department of Radiology, SERCOSA, Health Time, Carmelo Torres 2, 23007, Jaén, Spain (T.M.N., A.L.); Peripheral Nerve and Plexus Department, Centro Rossi, Buenos Aires, Argentina (R.B.); Department of Radiology, Duke University Medical Center, Durham, N.C. (T.J.A.); RESSALTA, Health Time, Córdoba, Spain (J.R.d.V.); and Philips Iberia, Madrid, Spain (P.M.)
| | - Rafael Barousse
- From the MRI Section, Department of Radiology, SERCOSA, Health Time, Carmelo Torres 2, 23007, Jaén, Spain (T.M.N., A.L.); Peripheral Nerve and Plexus Department, Centro Rossi, Buenos Aires, Argentina (R.B.); Department of Radiology, Duke University Medical Center, Durham, N.C. (T.J.A.); RESSALTA, Health Time, Córdoba, Spain (J.R.d.V.); and Philips Iberia, Madrid, Spain (P.M.)
| | - Timothy J. Amrhein
- From the MRI Section, Department of Radiology, SERCOSA, Health Time, Carmelo Torres 2, 23007, Jaén, Spain (T.M.N., A.L.); Peripheral Nerve and Plexus Department, Centro Rossi, Buenos Aires, Argentina (R.B.); Department of Radiology, Duke University Medical Center, Durham, N.C. (T.J.A.); RESSALTA, Health Time, Córdoba, Spain (J.R.d.V.); and Philips Iberia, Madrid, Spain (P.M.)
| | - Javier Royuela-del-Val
- From the MRI Section, Department of Radiology, SERCOSA, Health Time, Carmelo Torres 2, 23007, Jaén, Spain (T.M.N., A.L.); Peripheral Nerve and Plexus Department, Centro Rossi, Buenos Aires, Argentina (R.B.); Department of Radiology, Duke University Medical Center, Durham, N.C. (T.J.A.); RESSALTA, Health Time, Córdoba, Spain (J.R.d.V.); and Philips Iberia, Madrid, Spain (P.M.)
| | - Paula Montesinos
- From the MRI Section, Department of Radiology, SERCOSA, Health Time, Carmelo Torres 2, 23007, Jaén, Spain (T.M.N., A.L.); Peripheral Nerve and Plexus Department, Centro Rossi, Buenos Aires, Argentina (R.B.); Department of Radiology, Duke University Medical Center, Durham, N.C. (T.J.A.); RESSALTA, Health Time, Córdoba, Spain (J.R.d.V.); and Philips Iberia, Madrid, Spain (P.M.)
| | - Antonio Luna
- From the MRI Section, Department of Radiology, SERCOSA, Health Time, Carmelo Torres 2, 23007, Jaén, Spain (T.M.N., A.L.); Peripheral Nerve and Plexus Department, Centro Rossi, Buenos Aires, Argentina (R.B.); Department of Radiology, Duke University Medical Center, Durham, N.C. (T.J.A.); RESSALTA, Health Time, Córdoba, Spain (J.R.d.V.); and Philips Iberia, Madrid, Spain (P.M.)
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16
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Aarabi B, Akhtar-Danesh N, Chryssikos T, Shanmuganathan K, Schwartzbauer GT, Simard JM, Olexa J, Sansur CA, Crandall KM, Mushlin H, Kole MJ, Le EJ, Wessell AP, Pratt N, Cannarsa G, Lomangino C, Scarboro M, Aresco C, Oliver J, Caffes N, Carbine S, Mori K. Efficacy of Ultra-Early (< 12 h), Early (12-24 h), and Late (>24-138.5 h) Surgery with Magnetic Resonance Imaging-Confirmed Decompression in American Spinal Injury Association Impairment Scale Grades A, B, and C Cervical Spinal Cord Injury. J Neurotrauma 2020; 37:448-457. [PMID: 31310155 PMCID: PMC6978784 DOI: 10.1089/neu.2019.6606] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
In cervical traumatic spinal cord injury (TSCI), the therapeutic effect of timing of surgery on neurological recovery remains uncertain. Additionally, the relationship between extent of decompression, imaging biomarker evidence of injury severity, and outcome is incompletely understood. We investigated the effect of timing of decompression on long-term neurological outcome in patients with complete spinal cord decompression confirmed on postoperative magnetic resonance imaging (MRI). American Spinal Injury Association (ASIA) Impairment Scale (AIS) grade conversion was determined in 72 AIS grades A, B, and C patients 6 months after confirmed decompression. Thirty-two patients underwent decompressive surgery ultra-early (< 12 h), 25 underwent decompressive surgery early (12-24 h), and 15 underwent decompressive surgery late (> 24-138.5 h) after injury. Age, gender, injury mechanism, intramedullary lesion length (IMLL) on MRI, admission ASIA motor score, and surgical technique were not statistically different among groups. Motor complete patients (p = 0.009) and those with fracture dislocations (p = 0.01) tended to be operated on earlier. Improvement of one grade or more was present in 55.6% of AIS grade A, 60.9% of AIS grade B, and 86.4% of AIS grade C patients. Admission AIS motor score (p = 0.0004) and pre-operative IMLL (p = 0.00001) were the strongest predictors of neurological outcome. AIS grade improvement occurred in 65.6%, 60%, and 80% of patients who underwent decompression ultra-early, early, and late, respectively (p = 0.424). Multiple regression analysis revealed that IMLL was the only significant variable predictive of AIS grade conversion to a better grade (odds ratio, 0.908; confidence interval [CI], 0.862-0.957; p < 0.001). We conclude that in patients with post-operative MRI confirmation of complete decompression following cervical TSCI, pre-operative IMLL, not the timing of surgery, determines long-term neurological outcome.
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Affiliation(s)
- Bizhan Aarabi
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland
- R. Adams Cowley Shock Trauma Center, University of Maryland School of Medicine, Baltimore, Maryland
| | - Noori Akhtar-Danesh
- School of Nursing and Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Ontario, Canada
| | - Timothy Chryssikos
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland
| | | | - Gary T. Schwartzbauer
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland
- R. Adams Cowley Shock Trauma Center, University of Maryland School of Medicine, Baltimore, Maryland
| | - J. Marc Simard
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Joshua Olexa
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Charles A. Sansur
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Kenneth M. Crandall
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Harry Mushlin
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Matthew J. Kole
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Elizabeth J. Le
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Aaron P. Wessell
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Nathan Pratt
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Gregory Cannarsa
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Cara Lomangino
- R. Adams Cowley Shock Trauma Center, University of Maryland School of Medicine, Baltimore, Maryland
| | - Maureen Scarboro
- R. Adams Cowley Shock Trauma Center, University of Maryland School of Medicine, Baltimore, Maryland
| | - Carla Aresco
- R. Adams Cowley Shock Trauma Center, University of Maryland School of Medicine, Baltimore, Maryland
| | - Jeffrey Oliver
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Nicholas Caffes
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Stephen Carbine
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Kanami Mori
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland
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17
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Freund P, Seif M, Weiskopf N, Friston K, Fehlings MG, Thompson AJ, Curt A. MRI in traumatic spinal cord injury: from clinical assessment to neuroimaging biomarkers. Lancet Neurol 2019; 18:1123-1135. [DOI: 10.1016/s1474-4422(19)30138-3] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 03/22/2019] [Accepted: 03/28/2019] [Indexed: 01/18/2023]
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18
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David G, Mohammadi S, Martin AR, Cohen-Adad J, Weiskopf N, Thompson A, Freund P. Traumatic and nontraumatic spinal cord injury: pathological insights from neuroimaging. Nat Rev Neurol 2019; 15:718-731. [PMID: 31673093 DOI: 10.1038/s41582-019-0270-5] [Citation(s) in RCA: 100] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/18/2019] [Indexed: 01/23/2023]
Abstract
Pathophysiological changes in the spinal cord white and grey matter resulting from injury can be observed with MRI techniques. These techniques provide sensitive markers of macrostructural and microstructural tissue integrity, which correlate with histological findings. Spinal cord MRI findings in traumatic spinal cord injury (tSCI) and nontraumatic spinal cord injury - the most common form of which is degenerative cervical myelopathy (DCM) - have provided important insights into the pathophysiological processes taking place not just at the focal injury site but also rostral and caudal to the spinal injury. Although tSCI and DCM have different aetiologies, they show similar degrees of spinal cord pathology remote from the injury site, suggesting the involvement of similar secondary degenerative mechanisms. Advanced quantitative MRI protocols that are sensitive to spinal cord pathology have the potential to improve diagnosis and, more importantly, predict outcomes in patients with tSCI or nontraumatic spinal cord injury. This Review describes the insights into tSCI and DCM that have been revealed by neuroimaging and outlines current activities and future directions for the field.
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Affiliation(s)
- Gergely David
- Spinal Cord Injury Center Balgrist, University Hospital Zurich, University of Zurich, Zurich, Switzerland.,Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Siawoosh Mohammadi
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Wellcome Centre for Human Neuroimaging, UCL Institute of Neurology, London, UK
| | - Allan R Martin
- Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, Ontario, Canada
| | - Julien Cohen-Adad
- NeuroPoly Lab, Institute of Biomedical Engineering, Polytechnique Montreal, Montreal, Quebec, Canada
| | - Nikolaus Weiskopf
- Wellcome Centre for Human Neuroimaging, UCL Institute of Neurology, London, UK.,Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Alan Thompson
- Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, London, UK
| | - Patrick Freund
- Spinal Cord Injury Center Balgrist, University Hospital Zurich, University of Zurich, Zurich, Switzerland. .,Wellcome Centre for Human Neuroimaging, UCL Institute of Neurology, London, UK. .,Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany. .,Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, London, UK. .,Department of Neurology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
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19
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Cadotte DW, Akbar MA, Fehlings MG, Stroman PW, Cohen-Adad J. What Has Been Learned from Magnetic Resonance Imaging Examination of the Injured Human Spinal Cord: A Canadian Perspective. J Neurotrauma 2019; 35:1942-1957. [PMID: 30074873 DOI: 10.1089/neu.2018.5903] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Magnetic resonance imaging (MRI) has transformed the way surgeons and researchers study and treat spinal cord injury. In this narrative review, we explore the historical context of imaging the human spinal cord and describe how MRI has evolved from providing the first visualization of the human spinal cord in the 1980s to a remarkable set of imaging tools today. The article focuses in particular on the role of Canadian researchers to this field. We begin by outlining the clinical context of traumatic injury to the human spinal cord and describe why current MRI standards fall short when it comes to treating this disabling condition. Parts 2 and 3 of this work explore an exciting and dramatic shift in the use of MRI technology to aid in our understanding and treatment of traumatic injury to the spinal cord. We explore the use of functional imaging (part 2) and structural imaging (part 3) and explore how these techniques have evolved, how they are used, and the challenges that we face for continued refinement and application to patients who live with the neurological and functional deficits caused by injury to the delicate spinal cord.
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Affiliation(s)
- David W Cadotte
- 1 University of Calgary Spine Program, Division of Neurosurgery, Department of Clinical Neurosciences, University of Calgary , Foothills Medical Centre, Calgary, Alberta, Canada
| | - M Ali Akbar
- 2 Department of Surgery, Division of Neurosurgery and Spinal Program, Toronto Western Hospital, University of Toronto , Toronto, Ontario, Canada
| | - Michael G Fehlings
- 2 Department of Surgery, Division of Neurosurgery and Spinal Program, Toronto Western Hospital, University of Toronto , Toronto, Ontario, Canada
| | - Patrick W Stroman
- 3 Centre for Neuroscience Studies, Queens University , Kingston, Ontario, Canada
| | - Julien Cohen-Adad
- 4 NeuroPoly Lab, Institute of Biomedical Engineering , Polytechnique Montreal, Montreal, Quebéc, Canada .,5 Functional Neuroimaging Unit, CRIUGM, Université de Montréal , Montreal, Quebéc, Canada
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20
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Rao JS, Liu Z, Zhao C, Wei RH, Liu RX, Zhao W, Zhou X, Tian PY, Yang ZY, Li XG. Image correction for diffusion tensor imaging of Rhesus monkey thoracic spinal cord. J Med Primatol 2019; 48:320-328. [PMID: 31148186 DOI: 10.1111/jmp.12422] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2018] [Revised: 04/03/2019] [Accepted: 05/12/2019] [Indexed: 02/02/2023]
Abstract
BACKGROUND The relatively tiny spinal cord of non-human primate (NHP) causes increased challenge in diffusion tensor imaging (DTI) post-processing. This study aimed to establish a reliable correction strategy applied to clinical DTI images of NHP. METHODS Six normal and partial spinal cord injury (SCI) rhesus monkeys underwent 3T MR scanning. A correction strategy combining multiple iterations and non-rigid deformation was used for DTI image post-processing. Quantitative evaluations were then conducted to investigate effects of distortion correction. RESULTS After correction, longitudinal geometric distortion, global distortion, and residual distance errors were all significantly decreased (P < 0.05). Fractional anisotropy at the injured site was remarkably lower than that at the contralateral site (P = 0.0488) and was substantially lower than those at the adjacent superior (P = 0.0157) and inferior (P = 0.0128) areas at the same side. CONCLUSIONS Our image correction strategy can improve the quality of the DTI images of NHP thoracic cords, contributing to the development of SCI preclinical research.
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Affiliation(s)
- Jia-Sheng Rao
- Beijing Key Laboratory for Biomaterials and Neural Regeneration, Department of Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China.,Beijing International Cooperation Bases for Science and Technology on Biomaterials and Neural Regeneration, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, China
| | - Zuxiang Liu
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,Innovation Center of Excellence on Brain Science, Chinese Academy of Sciences, Beijing, China.,Department of Biology, College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Can Zhao
- Beijing International Cooperation Bases for Science and Technology on Biomaterials and Neural Regeneration, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, China.,Department of Measurement Control and Information Technology, School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing, China
| | - Rui-Han Wei
- Beijing Key Laboratory for Biomaterials and Neural Regeneration, Department of Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Ruo-Xi Liu
- Beijing Key Laboratory for Biomaterials and Neural Regeneration, Department of Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Wen Zhao
- Department of Neurobiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Xia Zhou
- Beijing Key Laboratory for Biomaterials and Neural Regeneration, Department of Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Peng-Yu Tian
- Beijing Key Laboratory for Biomaterials and Neural Regeneration, Department of Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Zhao-Yang Yang
- Beijing International Cooperation Bases for Science and Technology on Biomaterials and Neural Regeneration, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, China.,Department of Neurobiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Xiao-Guang Li
- Beijing Key Laboratory for Biomaterials and Neural Regeneration, Department of Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China.,Beijing International Cooperation Bases for Science and Technology on Biomaterials and Neural Regeneration, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, China
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21
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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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22
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David G, Seif M, Huber E, Hupp M, Rosner J, Dietz V, Weiskopf N, Mohammadi S, Freund P. In vivo evidence of remote neural degeneration in the lumbar enlargement after cervical injury. Neurology 2019; 92:e1367-e1377. [PMID: 30770423 PMCID: PMC6511094 DOI: 10.1212/wnl.0000000000007137] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 11/07/2018] [Indexed: 01/14/2023] Open
Abstract
OBJECTIVE To characterize remote secondary neurodegeneration of spinal tracts and neurons below a cervical spinal cord injury (SCI) and its relation to the severity of injury, the integrity of efferent and afferent pathways, and clinical impairment. METHODS A comprehensive high-resolution MRI protocol was acquired in 17 traumatic cervical SCI patients and 14 controls at 3T. At the cervical lesion, a sagittal T2-weighted scan provided information on the width of preserved midsagittal tissue bridges. In the lumbar enlargement, high-resolution T2*-weighted and diffusion-weighted scans were used to calculate tissue-specific cross-sectional areas and diffusion indices, respectively. Regression analyses determined associations between MRI readouts and the electrophysiologic and clinical measures. RESULTS At the cervical injury level, preserved midsagittal tissue bridges were present in the majority of patients. In the lumbar enlargement, neurodegeneration-in terms of macrostructural and microstructural MRI changes-was evident in the white matter and ventral and dorsal horns. Patients with thinner midsagittal tissue bridges had smaller ventral horn area, higher radial diffusivity in the gray matter, smaller motor evoked potential amplitude from the lower extremities, and lower motor score. In addition, smaller width of midsagittal tissue bridges was also associated with smaller tibialis sensory evoked potential amplitude and lower light-touch score. CONCLUSIONS This study shows extensive tissue-specific cord pathology in infralesional spinal networks following cervical SCI, its magnitude relating to lesion severity, electrophysiologic integrity, and clinical impairment of the lower extremity. The clinical eloquence of remote neurodegenerative changes speaks to the application of neuroimaging biomarkers in diagnostic workup and planning of clinical trials.
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Affiliation(s)
- Gergely David
- From the Spinal Cord Injury Center Balgrist (G.D., M.S., E.H., M.H., J.R., V.D., P.F.), University Hospital Zurich, University of Zurich, Switzerland; Wellcome Trust Centre for Neuroimaging (N.W., S.M., P.F.), UCL Institute of Neurology, London, UK; Department of Neurophysics (M.S., N.W., P.F.), Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig; and Department of Systems Neuroscience (S.M.), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Maryam Seif
- From the Spinal Cord Injury Center Balgrist (G.D., M.S., E.H., M.H., J.R., V.D., P.F.), University Hospital Zurich, University of Zurich, Switzerland; Wellcome Trust Centre for Neuroimaging (N.W., S.M., P.F.), UCL Institute of Neurology, London, UK; Department of Neurophysics (M.S., N.W., P.F.), Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig; and Department of Systems Neuroscience (S.M.), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Eveline Huber
- From the Spinal Cord Injury Center Balgrist (G.D., M.S., E.H., M.H., J.R., V.D., P.F.), University Hospital Zurich, University of Zurich, Switzerland; Wellcome Trust Centre for Neuroimaging (N.W., S.M., P.F.), UCL Institute of Neurology, London, UK; Department of Neurophysics (M.S., N.W., P.F.), Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig; and Department of Systems Neuroscience (S.M.), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Markus Hupp
- From the Spinal Cord Injury Center Balgrist (G.D., M.S., E.H., M.H., J.R., V.D., P.F.), University Hospital Zurich, University of Zurich, Switzerland; Wellcome Trust Centre for Neuroimaging (N.W., S.M., P.F.), UCL Institute of Neurology, London, UK; Department of Neurophysics (M.S., N.W., P.F.), Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig; and Department of Systems Neuroscience (S.M.), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Jan Rosner
- From the Spinal Cord Injury Center Balgrist (G.D., M.S., E.H., M.H., J.R., V.D., P.F.), University Hospital Zurich, University of Zurich, Switzerland; Wellcome Trust Centre for Neuroimaging (N.W., S.M., P.F.), UCL Institute of Neurology, London, UK; Department of Neurophysics (M.S., N.W., P.F.), Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig; and Department of Systems Neuroscience (S.M.), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Volker Dietz
- From the Spinal Cord Injury Center Balgrist (G.D., M.S., E.H., M.H., J.R., V.D., P.F.), University Hospital Zurich, University of Zurich, Switzerland; Wellcome Trust Centre for Neuroimaging (N.W., S.M., P.F.), UCL Institute of Neurology, London, UK; Department of Neurophysics (M.S., N.W., P.F.), Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig; and Department of Systems Neuroscience (S.M.), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Nikolaus Weiskopf
- From the Spinal Cord Injury Center Balgrist (G.D., M.S., E.H., M.H., J.R., V.D., P.F.), University Hospital Zurich, University of Zurich, Switzerland; Wellcome Trust Centre for Neuroimaging (N.W., S.M., P.F.), UCL Institute of Neurology, London, UK; Department of Neurophysics (M.S., N.W., P.F.), Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig; and Department of Systems Neuroscience (S.M.), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Siawoosh Mohammadi
- From the Spinal Cord Injury Center Balgrist (G.D., M.S., E.H., M.H., J.R., V.D., P.F.), University Hospital Zurich, University of Zurich, Switzerland; Wellcome Trust Centre for Neuroimaging (N.W., S.M., P.F.), UCL Institute of Neurology, London, UK; Department of Neurophysics (M.S., N.W., P.F.), Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig; and Department of Systems Neuroscience (S.M.), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Patrick Freund
- From the Spinal Cord Injury Center Balgrist (G.D., M.S., E.H., M.H., J.R., V.D., P.F.), University Hospital Zurich, University of Zurich, Switzerland; Wellcome Trust Centre for Neuroimaging (N.W., S.M., P.F.), UCL Institute of Neurology, London, UK; Department of Neurophysics (M.S., N.W., P.F.), Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig; and Department of Systems Neuroscience (S.M.), University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
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Cohen-Adad J. Microstructural imaging in the spinal cord and validation strategies. Neuroimage 2018; 182:169-183. [PMID: 29635029 DOI: 10.1016/j.neuroimage.2018.04.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 03/02/2018] [Accepted: 04/06/2018] [Indexed: 12/13/2022] Open
Abstract
In vivo histology using magnetic resonance imaging (MRI) is a newly emerging research field that aims to non-invasively characterize tissue microstructure. The implications of in vivo histology are many, from discovering novel biomarkers to studying human development, to providing tools for disease diagnosis and monitoring the effects of novel treatments on tissue. This review focuses on quantitative MRI (qMRI) techniques that are used to map spinal cord microstructure. Opening with a rationale for non-invasive imaging of the spinal cord, this article continues with a brief overview of the existing MRI techniques for axon and myelin imaging, followed by the specific challenges and potential solutions for acquiring and processing such data. The final part of this review focuses on histological validation, with suggested tissue preparation, acquisition and processing protocols for large-scale microscopy.
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Affiliation(s)
- J Cohen-Adad
- NeuroPoly Lab, Institute of Biomedical Engineering, Polytechnique Montreal, Montreal, QC, Canada; Functional Neuroimaging Unit, CRIUGM, Université de Montréal, Montreal, QC, Canada.
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24
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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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25
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Shatil AS, Uddin MN, Matsuda KM, Figley CR. Quantitative Ex Vivo MRI Changes due to Progressive Formalin Fixation in Whole Human Brain Specimens: Longitudinal Characterization of Diffusion, Relaxometry, and Myelin Water Fraction Measurements at 3T. Front Med (Lausanne) 2018. [PMID: 29515998 PMCID: PMC5826187 DOI: 10.3389/fmed.2018.00031] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Purpose Postmortem MRI can be used to reveal important pathologies and establish radiology-pathology correlations. However, quantitative MRI values are altered by tissue fixation. Therefore, the purpose of this study was to investigate time-dependent effects of formalin fixation on MRI relaxometry (T1 and T2), diffusion tensor imaging (fractional anisotropy, FA; and mean diffusivity, MD), and myelin water fraction (MWF) measurements throughout intact human brain specimens. Methods Two whole, neurologically-healthy human brains were immersed in 10% formalin solution and scanned at 13 time points between 0 and 1,032 h. Whole-brain maps of longitudinal (T1) and transverse (T2) relaxation times, FA, MD, and MWF were generated at each time point to illustrate spatiotemporal changes, and region-of-interest analyses were then performed in eight brain structures to quantify temporal changes with progressive fixation. Results Although neither of the diffusion measures (FA nor MD) showed significant changes as a function of formalin fixation time, both T1 and T2-relaxation times significantly decreased, and MWF estimates significantly increased with progressive fixation until (and likely beyond) our final measurements were taken at 1,032 h. Conclusion These results suggest that T1-relaxation, T2-relaxation and MWF estimates must be performed quite early in the fixation process to avoid formalin-induced changes compared to in vivo values; and furthermore, that different ex vivo scans within an experiment must be acquired at consistent (albeit still early) fixation intervals to avoid fixative-related differences between samples. Conversely, ex vivo diffusion measures (FA and MD) appear to depend more on other factors (e.g., pulse sequence optimization, sample temperature, etc.).
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Affiliation(s)
- Anwar S Shatil
- Biomedical Engineering Graduate Program, University of Manitoba, Winnipeg, MB, Canada.,Neuroscience Research Program, Kleysen Institute for Advanced Medicine, Winnipeg Health Sciences Centre, Winnipeg, MB, Canada
| | - Md Nasir Uddin
- Neuroscience Research Program, Kleysen Institute for Advanced Medicine, Winnipeg Health Sciences Centre, Winnipeg, MB, Canada.,Department of Radiology, University of Manitoba, Winnipeg, MB, Canada.,Division of Diagnostic Imaging, Winnipeg Health Sciences Centre, Winnipeg, MB, Canada
| | - Kant M Matsuda
- Biomedical Engineering Graduate Program, University of Manitoba, Winnipeg, MB, Canada.,Department of Pathology, University of Manitoba, Winnipeg, MB, Canada
| | - Chase R Figley
- Biomedical Engineering Graduate Program, University of Manitoba, Winnipeg, MB, Canada.,Neuroscience Research Program, Kleysen Institute for Advanced Medicine, Winnipeg Health Sciences Centre, Winnipeg, MB, Canada.,Department of Radiology, University of Manitoba, Winnipeg, MB, Canada.,Division of Diagnostic Imaging, Winnipeg Health Sciences Centre, Winnipeg, MB, Canada.,Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD, United States
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26
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Budde MD, Skinner NP, Muftuler LT, Schmit BD, Kurpad SN. Optimizing Filter-Probe Diffusion Weighting in the Rat Spinal Cord for Human Translation. Front Neurosci 2017; 11:706. [PMID: 29311786 PMCID: PMC5742102 DOI: 10.3389/fnins.2017.00706] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 12/01/2017] [Indexed: 12/15/2022] Open
Abstract
Diffusion tensor imaging (DTI) is a promising biomarker of spinal cord injury (SCI). In the acute aftermath, DTI in SCI animal models consistently demonstrates high sensitivity and prognostic performance, yet translation of DTI to acute human SCI has been limited. In addition to technical challenges, interpretation of the resulting metrics is ambiguous, with contributions in the acute setting from both axonal injury and edema. Novel diffusion MRI acquisition strategies such as double diffusion encoding (DDE) have recently enabled detection of features not available with DTI or similar methods. In this work, we perform a systematic optimization of DDE using simulations and an in vivo rat model of SCI and subsequently implement the protocol to the healthy human spinal cord. First, two complementary DDE approaches were evaluated using an orientationally invariant or a filter-probe diffusion encoding approach. While the two methods were similar in their ability to detect acute SCI, the filter-probe DDE approach had greater predictive power for functional outcomes. Next, the filter-probe DDE was compared to an analogous single diffusion encoding (SDE) approach, with the results indicating that in the spinal cord, SDE provides similar contrast with improved signal to noise. In the SCI rat model, the filter-probe SDE scheme was coupled with a reduced field of view (rFOV) excitation, and the results demonstrate high quality maps of the spinal cord without contamination from edema and cerebrospinal fluid, thereby providing high sensitivity to injury severity. The optimized protocol was demonstrated in the healthy human spinal cord using the commercially-available diffusion MRI sequence with modifications only to the diffusion encoding directions. Maps of axial diffusivity devoid of CSF partial volume effects were obtained in a clinically feasible imaging time with a straightforward analysis and variability comparable to axial diffusivity derived from DTI. Overall, the results and optimizations describe a protocol that mitigates several difficulties with DTI of the spinal cord. Detection of acute axonal damage in the injured or diseased spinal cord will benefit the optimized filter-probe diffusion MRI protocol outlined here.
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Affiliation(s)
- Matthew D Budde
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Nathan P Skinner
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, United States.,Medical Scientist Training Program, Medical College of Wisconsin, Milwaukee, WI, United States
| | - L Tugan Muftuler
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Brian D Schmit
- Department of Biomedical Engineering, Marquette University and the Medical College of Wisconsin, Milwaukee, WI, United States
| | - Shekar N Kurpad
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, United States
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27
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Weigel M, Bieri O. Spinal cord imaging using averaged magnetization inversion recovery acquisitions. Magn Reson Med 2017; 79:1870-1881. [PMID: 28714105 DOI: 10.1002/mrm.26833] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2016] [Revised: 06/19/2017] [Accepted: 06/19/2017] [Indexed: 11/06/2022]
Abstract
PURPOSE To establish a novel approach for fast high-resolution spinal cord (SC) imaging using averaged magnetization inversion recovery acquisitions (AMIRA). METHODS The AMIRA concept is based on an inversion recovery (IR) prepared, segmented, and time-limited cine balanced steady state free precession sequence. Typically, for the fastest SC imaging without any signal averaging, eight consecutive images in time with an in-plane resolution of 0.67 × 0.67 mm2 and 6 mm to 8 mm slice thickness are acquired in 51 s. AMIRA does not require parallel acquisition techniques. RESULTS AMIRA measures eight images of remarkable tissue contrast variation between spinal cord gray (GM) and white matter (WM) and cerebrospinal fluid (CSF). Following the AMIRA concept, averaging the first IR contrast images not only improves the signal-to-noise ratio but also offers a surprising enhancement of the contrast-to-noise ratio between GM and WM, whereas averaging the last images considerably improves the contrast-to-noise ratio between WM and CSF. These observations are supported by quantitative data. CONCLUSION The AMIRA concept provides 2D spinal cord imaging with multiple tissue contrasts and enhanced contrast-to-noise ratios with a typical 0.67 × 0.67 mm2 in-plane resolution and a slice thickness between 4 mm and 8 mm acquired in only 1 to 2 min per slice. Magn Reson Med 79:1870-1881, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Matthias Weigel
- Department of Radiology, Division of Radiological Physics, University of Basel Hospital, Basel, Switzerland.,Department of Biomedical Engineering, University of Basel, Basel, Switzerland
| | - Oliver Bieri
- Department of Radiology, Division of Radiological Physics, University of Basel Hospital, Basel, Switzerland.,Department of Biomedical Engineering, University of Basel, Basel, Switzerland
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David G, Freund P, Mohammadi S. The efficiency of retrospective artifact correction methods in improving the statistical power of between-group differences in spinal cord DTI. Neuroimage 2017; 158:296-307. [PMID: 28669912 PMCID: PMC6168644 DOI: 10.1016/j.neuroimage.2017.06.051] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 06/19/2017] [Accepted: 06/21/2017] [Indexed: 11/10/2022] Open
Abstract
Diffusion tensor imaging (DTI) is a promising approach for investigating the white matter microstructure of the spinal cord. However, it suffers from severe susceptibility, physiological, and instrumental artifacts present in the cord. Retrospective correction techniques are popular approaches to reduce these artifacts, because they are widely applicable and do not increase scan time. In this paper, we present a novel outlier rejection approach (reliability masking) which is designed to supplement existing correction approaches by excluding irreversibly corrupted and thus unreliable data points from the DTI index maps. Then, we investigate how chains of retrospective correction techniques including (i) registration, (ii) registration and robust fitting, and (iii) registration, robust fitting, and reliability masking affect the statistical power of a previously reported finding of lower fractional anisotropy values in the posterior column and lateral corticospinal tracts in cervical spondylotic myelopathy (CSM) patients. While established post-processing steps had small effect on the statistical power of the clinical finding (slice-wise registration: −0.5%, robust fitting: +0.6%), adding reliability masking to the post-processing chain increased it by 4.7%. Interestingly, reliability masking and registration affected the t-score metric differently: while the gain in statistical power due to reliability masking was mainly driven by decreased variability in both groups, registration slightly increased variability. In conclusion, reliability masking is particularly attractive for neuroscience and clinical research studies, as it increases statistical power by reducing group variability and thus provides a cost-efficient alternative to increasing the group size. A novel outlier rejection technique (reliability masking) is introduced. Standard artifact correction has little effect on the statistical power of between-group differences. Reliability masking improves the statistical power of between-group differences. This improvement is driven by decreased group-level variability.
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Affiliation(s)
- Gergely David
- Spinal Cord Injury Center Balgrist, Balgrist University Hospital, Zurich, Switzerland; Department of Systems Neuroscience, Medical Center Hamburg-Eppendorf, Hamburg, Germany.
| | - Patrick Freund
- Spinal Cord Injury Center Balgrist, Balgrist University Hospital, Zurich, Switzerland; Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London, London, United Kingdom; Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, University College London, London, United Kingdom; Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Siawoosh Mohammadi
- Department of Systems Neuroscience, Medical Center Hamburg-Eppendorf, Hamburg, Germany; Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London, London, United Kingdom; Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
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Grabher P, Mohammadi S, David G, Freund P. Neurodegeneration in the Spinal Ventral Horn Prior to Motor Impairment in Cervical Spondylotic Myelopathy. J Neurotrauma 2017; 34:2329-2334. [PMID: 28462691 DOI: 10.1089/neu.2017.4980] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Remote gray matter pathology has been suggested rostral to the compression site in cervical spondylotic myelopathy (CSM). We therefore assessed neurodegeneration in the gray matter ventral and dorsal horns. Twenty patients with CSM and 18 healthy subjects underwent a high-resolution structural and diffusion magnetic resonance imaging protocol at vertebra C2/C3. Patients received comprehensive clinical assessments. T2*-weighted data provided cross-sectional area measurements of gray matter ventral and dorsal horns to identify atrophy. At the identical location, mean diffusivity (MD) and fractional anisotropy (FA) determined the microstructural integrity. Finally, the relationships between neurodegeneration occurring in the gray and white matter and clinical impairment were investigated. Patients suffered from mild-to-moderate CSM with mainly sensory impairment. In the ventral horns, cross-sectional area was not reduced (p = 0.863) but MD was increased (p = 0.045). The magnitude of MD changes within the ventral horn was associated with white matter diffusivity changes (MD: p = 0.013; FA: p = 0.028) within the lateral corticospinal tract. In contrast, dorsal horn cross-sectional area was reduced by 16.0% (p < 0.001) without alterations in diffusivity indices, compared with controls. No associations between the magnitude of ventral and dorsal horn neurodegeneration and clinical impairment were evident. Focal cord gray matter pathology is evident remote to the compression site in vivo in CSM patients. Microstructural changes in the ventral horns (i.e., motoneurons) related to corticospinal tract integrity in the absence of atrophy and marked motor impairment. Dorsal horn atrophy corresponded to main clinical representation of sensory impairment. Thus, neuroimaging biomarkers of cord gray matter integrity reveal focal neurodegeneration prior to marked clinical impairment and thus could serve as predictors of ensuing impairment in CSM patients.
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Affiliation(s)
- Patrick Grabher
- 1 Spinal Cord Injury Center Balgrist, University Hospital Zurich, University of Zurich , Zurich, Switzerland
| | - Siawoosh Mohammadi
- 2 Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf , Hamburg, Germany .,3 Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London , London, United Kingdom .,4 Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences , Leipzig, Germany
| | - Gergely David
- 1 Spinal Cord Injury Center Balgrist, University Hospital Zurich, University of Zurich , Zurich, Switzerland
| | - Patrick Freund
- 1 Spinal Cord Injury Center Balgrist, University Hospital Zurich, University of Zurich , Zurich, Switzerland .,3 Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London , London, United Kingdom .,4 Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences , Leipzig, Germany .,5 Department of Brain Repair and Rehabilitation, Institute of Neurology, University College London , London, United Kingdom
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Crombe A, Alberti N, Hiba B, Uettwiller M, Dousset V, Tourdias T. Cervical Spinal Cord DTI Is Improved by Reduced FOV with Specific Balance between the Number of Diffusion Gradient Directions and Averages. AJNR Am J Neuroradiol 2016; 37:2163-2170. [PMID: 27365330 DOI: 10.3174/ajnr.a4850] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 04/25/2016] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Reduced-FOV DTI is promising for exploring the cervical spinal cord, but the optimal set of parameters needs to be clarified. We hypothesized that the number of excitations should be favored over the number of diffusion gradient directions regarding the strong orientation of the cord in a single rostrocaudal axis. MATERIALS AND METHODS Fifteen healthy individuals underwent cervical spinal cord MR imaging at 3T, including an anatomic 3D-Multi-Echo Recombined Gradient Echo, high-resolution full-FOV DTI with a NEX of 3 and 20 diffusion gradient directions and 5 sets of reduced-FOV DTIs differently balanced in terms of NEX/number of diffusion gradient directions: (NEX/number of diffusion gradient directions = 3/20, 5/16, 7/12, 9/9, and 12/6). Each DTI sequence lasted 4 minutes 30 seconds, an acceptable duration, to cover C1-C4 in the axial plane. Fractional anisotropy maps and tractograms were reconstructed. Qualitatively, 2 radiologists rated the DTI sets blinded to the sequence. Quantitatively, we compared distortions, SNR, variance of fractional anisotropy values, and numbers of detected fibers. RESULTS Qualitatively, reduced-FOV DTI sequences with a NEX of ≥5 were significantly better rated than the full-FOV DTI and the reduced-FOV DTI with low NEX (N = 3) and a high number of diffusion gradient directions (D = 20). Quantitatively, the best trade-off was reached by the reduced-FOV DTI with a NEX of 9 and 9 diffusion gradient directions, which provided significantly fewer artifacts, higher SNR on trace at b = 750 s/mm2 and an increased number of fibers tracked while maintaining similar fractional anisotropy values and dispersion. CONCLUSIONS Optimized reduced-FOV DTI improves spinal cord imaging. The best compromise was obtained with a NEX of 9 and 9 diffusion gradient directions, which emphasizes the need for increasing the NEX at the expense of the number of diffusion gradient directions for spinal cord DTI contrary to brain DTI.
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Affiliation(s)
- A Crombe
- From the Centre Hospitalier Universitaire de Bordeaux (A.C., V.D., T.T.), Service de NeuroImagerie Diagnostique de Thérapeutique, Bordeaux, France
- Institut National de la Santé et de la Recherche Médicale U1215 (A.C., V.D., T.T.), Physiopathologie de la Plasticité Neuronale, Bordeaux, France
- Institut de Bio-Imagerie de Bordeaux (A.C., N.A., B.H., V.D., T.T.), Université de Bordeaux, Bordeaux, France
| | - N Alberti
- Institut de Bio-Imagerie de Bordeaux (A.C., N.A., B.H., V.D., T.T.), Université de Bordeaux, Bordeaux, France
- Centre de Résonance Magnétique des Systèmes Biologiques (N.A., B.H.), Centre National de la Recherche Scientifique Unité Mixte de Recherche 5536, Bordeaux, France
| | - B Hiba
- Institut de Bio-Imagerie de Bordeaux (A.C., N.A., B.H., V.D., T.T.), Université de Bordeaux, Bordeaux, France
- Centre de Résonance Magnétique des Systèmes Biologiques (N.A., B.H.), Centre National de la Recherche Scientifique Unité Mixte de Recherche 5536, Bordeaux, France
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine (B.H.), Centre National de la Recherche Scientifique Unité Mixte de Recherche 5287, Bordeaux, France
| | - M Uettwiller
- GE Healthcare (M.U.), Vélizy-Villacoublay, France
| | - V Dousset
- From the Centre Hospitalier Universitaire de Bordeaux (A.C., V.D., T.T.), Service de NeuroImagerie Diagnostique de Thérapeutique, Bordeaux, France
- Institut National de la Santé et de la Recherche Médicale U1215 (A.C., V.D., T.T.), Physiopathologie de la Plasticité Neuronale, Bordeaux, France
- Institut de Bio-Imagerie de Bordeaux (A.C., N.A., B.H., V.D., T.T.), Université de Bordeaux, Bordeaux, France
| | - T Tourdias
- From the Centre Hospitalier Universitaire de Bordeaux (A.C., V.D., T.T.), Service de NeuroImagerie Diagnostique de Thérapeutique, Bordeaux, France
- Institut National de la Santé et de la Recherche Médicale U1215 (A.C., V.D., T.T.), Physiopathologie de la Plasticité Neuronale, Bordeaux, France
- Institut de Bio-Imagerie de Bordeaux (A.C., N.A., B.H., V.D., T.T.), Université de Bordeaux, Bordeaux, France
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De Leener B, Lévy S, Dupont SM, Fonov VS, Stikov N, Louis Collins D, Callot V, Cohen-Adad J. SCT: Spinal Cord Toolbox, an open-source software for processing spinal cord MRI data. Neuroimage 2016; 145:24-43. [PMID: 27720818 DOI: 10.1016/j.neuroimage.2016.10.009] [Citation(s) in RCA: 348] [Impact Index Per Article: 43.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 10/03/2016] [Accepted: 10/04/2016] [Indexed: 11/17/2022] Open
Abstract
For the past 25 years, the field of neuroimaging has witnessed the development of several software packages for processing multi-parametric magnetic resonance imaging (mpMRI) to study the brain. These software packages are now routinely used by researchers and clinicians, and have contributed to important breakthroughs for the understanding of brain anatomy and function. However, no software package exists to process mpMRI data of the spinal cord. Despite the numerous clinical needs for such advanced mpMRI protocols (multiple sclerosis, spinal cord injury, cervical spondylotic myelopathy, etc.), researchers have been developing specific tools that, while necessary, do not provide an integrative framework that is compatible with most usages and that is capable of reaching the community at large. This hinders cross-validation and the possibility to perform multi-center studies. In this study we introduce the Spinal Cord Toolbox (SCT), a comprehensive software dedicated to the processing of spinal cord MRI data. SCT builds on previously-validated methods and includes state-of-the-art MRI templates and atlases of the spinal cord, algorithms to segment and register new data to the templates, and motion correction methods for diffusion and functional time series. SCT is tailored towards standardization and automation of the processing pipeline, versatility, modularity, and it follows guidelines of software development and distribution. Preliminary applications of SCT cover a variety of studies, from cross-sectional area measures in large databases of patients, to the precise quantification of mpMRI metrics in specific spinal pathways. We anticipate that SCT will bring together the spinal cord neuroimaging community by establishing standard templates and analysis procedures.
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Affiliation(s)
- Benjamin De Leener
- NeuroPoly Lab, Institute of Biomedical Engineering, Polytechnique Montreal, Montreal, QC, Canada
| | - Simon Lévy
- NeuroPoly Lab, Institute of Biomedical Engineering, Polytechnique Montreal, Montreal, QC, Canada; Functional Neuroimaging Unit, CRIUGM, Université de Montréal, Montreal, QC, Canada
| | - Sara M Dupont
- NeuroPoly Lab, Institute of Biomedical Engineering, Polytechnique Montreal, Montreal, QC, Canada
| | - Vladimir S Fonov
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Nikola Stikov
- NeuroPoly Lab, Institute of Biomedical Engineering, Polytechnique Montreal, Montreal, QC, Canada; Montreal Heart Institute, Montreal, QC, Canada
| | - D Louis Collins
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Virginie Callot
- Aix-Marseille Université, CNRS, CRMBM UMR 7339, Marseille, France; AP-HM, Hopital de la Timone, Pôle d'imagerie médicale, CEMEREM, Marseille, France
| | - Julien Cohen-Adad
- NeuroPoly Lab, Institute of Biomedical Engineering, Polytechnique Montreal, Montreal, QC, Canada; Functional Neuroimaging Unit, CRIUGM, Université de Montréal, Montreal, QC, Canada.
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32
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Wang Y, Cai W, Wang L, Xia R, Chen W, Zheng J, Gao F. Evaluation of the Differences of Myocardial Fibers between Acute and Chronic Myocardial Infarction: Application of Diffusion Tensor Magnetic Resonance Imaging in a Rhesus Monkey Model. Korean J Radiol 2016; 17:725-33. [PMID: 27587961 PMCID: PMC5007399 DOI: 10.3348/kjr.2016.17.5.725] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2015] [Accepted: 04/29/2016] [Indexed: 02/05/2023] Open
Abstract
Objective To understand microstructural changes after myocardial infarction (MI), we evaluated myocardial fibers of rhesus monkeys during acute or chronic MI, and identified the differences of myocardial fibers between acute and chronic MI. Materials and Methods Six fixed hearts of rhesus monkeys with left anterior descending coronary artery ligation for 1 hour or 84 days were scanned by diffusion tensor magnetic resonance imaging (MRI) to measure apparent diffusion coefficient (ADC), fractional anisotropy (FA) and helix angle (HA). Results Comparing with acute MI monkeys (FA: 0.59 ± 0.02; ADC: 5.0 ± 0.6 × 10-4 mm2/s; HA: 94.5 ± 4.4°), chronic MI monkeys showed remarkably decreased FA value (0.26 ± 0.03), increased ADC value (7.8 ± 0.8 × 10-4mm2/s), decreased HA transmural range (49.5 ± 4.6°) and serious defects on endocardium in infarcted regions. The HA in infarcted regions shifted to more components of negative left-handed helix in chronic MI monkeys (-38.3 ± 5.0°–11.2 ± 4.3°) than in acute MI monkeys (-41.4 ± 5.1°–53.1 ± 3.7°), but the HA in remote regions shifted to more components of positive right-handed helix in chronic MI monkeys (-43.8 ± 2.7°–66.5 ± 4.9°) than in acute MI monkeys (-59.5 ± 3.4°–64.9 ± 4.3°). Conclusion Diffusion tensor MRI method helps to quantify differences of mechanical microstructure and water diffusion of myocardial fibers between acute and chronic MI monkey's models.
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Affiliation(s)
- Yuqing Wang
- Department of Radiology, West China Hospital, Sichuan University, Sichuan 610041, China.; CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology of China, Beijing 100190, China
| | - Wei Cai
- Department of Radiology, West China Hospital, Sichuan University, Sichuan 610041, China.; Department of Radiology, Beijing Jishuitan Hospital, 4th Clinical Medical College of Peking University, Beijing 100035, China
| | - Lei Wang
- Department of Radiology, West China Hospital, Sichuan University, Sichuan 610041, China
| | - Rui Xia
- Department of Radiology, West China Hospital, Sichuan University, Sichuan 610041, China.; Department of Radiology, The First Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China
| | - Wei Chen
- Department of Radiology, West China Hospital, Sichuan University, Sichuan 610041, China.; Department of Radiology, The First Affiliated Hospital of Kunming Medical University, Yunnan 650032, China
| | - Jie Zheng
- Mallinckrodt Institute of Radiology, School of Medicine, Washington University, St. Louis, MO 63110, USA
| | - Fabao Gao
- Department of Radiology, West China Hospital, Sichuan University, Sichuan 610041, China
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Samson RS, Lévy S, Schneider T, Smith AK, Smith SA, Cohen-Adad J, Gandini Wheeler-Kingshott CAM. ZOOM or Non-ZOOM? Assessing Spinal Cord Diffusion Tensor Imaging Protocols for Multi-Centre Studies. PLoS One 2016; 11:e0155557. [PMID: 27171194 PMCID: PMC4865165 DOI: 10.1371/journal.pone.0155557] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 04/29/2016] [Indexed: 12/02/2022] Open
Abstract
The purpose of this study was to develop and evaluate two spinal cord (SC) diffusion tensor imaging (DTI) protocols, implemented at multiple sites (using scanners from two different manufacturers), one available on any clinical scanner, and one using more advanced options currently available in the research setting, and to use an automated processing method for unbiased quantification. DTI parameters are sensitive to changes in the diseased SC. However, imaging the cord can be technically challenging due to various factors including its small size, patient-related and physiological motion, and field inhomogeneities. Rapid acquisition sequences such as Echo Planar Imaging (EPI) are desirable but may suffer from image distortions. We present a multi-centre comparison of two acquisition protocols implemented on scanners from two different vendors (Siemens and Philips), one using a reduced field-of-view (rFOV) EPI sequence, and one only using options available on standard clinical scanners such as outer volume suppression (OVS). Automatic analysis was performed with the Spinal Cord Toolbox for unbiased and reproducible quantification of DTI metrics in the white matter. Images acquired using the rFOV sequence appear less distorted than those acquired using OVS alone. SC DTI parameter values obtained using both sequences at all sites were consistent with previous measurements made at 3T. For the same scanner manufacturer, DTI parameter inter-site SDs were smaller for the rFOV sequence compared to the OVS sequence. The higher inter-site reproducibility (for the same manufacturer and acquisition details, i.e. ZOOM data acquired at the two Philips sites) of rFOV compared to the OVS sequence supports the idea that making research options such as rFOV more widely available would improve accuracy of measurements obtained in multi-centre clinical trials. Future multi-centre studies should also aim to match the rFOV technique and signal-to-noise ratios in all sequences from different manufacturers/sites in order to avoid any bias in measured DTI parameters and ensure similar sensitivity to pathological changes.
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Affiliation(s)
- Rebecca S. Samson
- NMR Research Unit, Queen Square MS Centre, Department of Neuroinflammation, UCL Institute of Neurology, London, United Kingdom
- * E-mail:
| | - Simon Lévy
- Institute of Biomedical Engineering, Ecole Polytechnique de Montreal, Montreal, QC, Canada
- Functional Neuroimaging Unit, University of Montreal, Montreal, QC, Canada
| | - Torben Schneider
- NMR Research Unit, Queen Square MS Centre, Department of Neuroinflammation, UCL Institute of Neurology, London, United Kingdom
- Philips Healthcare, Guilford, Surrey, United Kingdom
| | - Alex K. Smith
- Vanderbilt University Institute of Imaging Science (VUIIS), Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Seth A. Smith
- Vanderbilt University Institute of Imaging Science (VUIIS), Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Julien Cohen-Adad
- Institute of Biomedical Engineering, Ecole Polytechnique de Montreal, Montreal, QC, Canada
- Functional Neuroimaging Unit, University of Montreal, Montreal, QC, Canada
| | - Claudia A. M. Gandini Wheeler-Kingshott
- NMR Research Unit, Queen Square MS Centre, Department of Neuroinflammation, UCL Institute of Neurology, London, United Kingdom
- Brain MRI 3T Center, C. Mondino National Neurological Institute, Pavia, Italy
- Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy
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Voxel-based analysis of grey and white matter degeneration in cervical spondylotic myelopathy. Sci Rep 2016; 6:24636. [PMID: 27095134 PMCID: PMC4837346 DOI: 10.1038/srep24636] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 04/04/2016] [Indexed: 12/21/2022] Open
Abstract
In this prospective study, we made an unbiased voxel-based analysis to investigate above-stenosis spinal degeneration and its relation to impairment in patients with cervical spondylotic myelopathy (CSM). Twenty patients and 18 controls were assessed with high-resolution MRI protocols above the level of stenosis. Cross-sectional areas of grey matter (GM), white matter (WM), and posterior columns (PC) were measured to determine atrophy. Diffusion indices assessed tract-specific integrity of PC and lateral corticospinal tracts (CST). Regression analysis was used to reveal relationships between MRI measures and clinical impairment. Patients showed mainly sensory impairment. Atrophy was prominent within the cervical WM (13.9%, p = 0.004), GM (7.2%, p = 0.043), and PC (16.1%, p = 0.005). Fractional anisotropy (FA) was reduced in the PC (−11.98%, p = 0.006) and lateral CST (−12.96%, p = 0.014). In addition, radial (+28.47%, p = 0.014), axial (+14.72%, p = 0.005), and mean (+16.50%, p = 0.001) diffusivities were increased in the PC. Light-touch score was associated with atrophy (R2 = 0.3559, p = 0.020) and FA (z score 3.74, p = 0.003) in the PC, as was functional independence and FA in the lateral CST (z score 3.68, p = 0.020). This study demonstrates voxel-based degeneration far above the stenosis at a level not directly affected by the compression and provides unbiased readouts of tract-specific changes that relate to impairment.
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Wang Y, Cai W, Wang L, Xia R. Evaluate the early changes of myocardial fibers in rhesus monkey during sub-acute stage of myocardial infarction using diffusion tensor magnetic resonance imaging. Magn Reson Imaging 2015; 34:391-6. [PMID: 26708038 DOI: 10.1016/j.mri.2015.12.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 12/12/2015] [Indexed: 02/05/2023]
Abstract
PURPOSE The deterioration of cardiac mechanical function starts from the micro-alterations in the myocardial fibers after myocardial infarction (MI) due to the heart beats derived from the systole and diastole of the myocardial fibers. So, we want to evaluate quantitatively the early changes of myocardial fibers in rhesus monkey during sub-acute MI stage. MATERIALS AND METHODS Three fixed hearts with infarction after left anterior descending coronary artery ligation for 7days and eight age-matched intact controls were scanned by ex-vivo diffusion tensor magnetic resonance imaging (DT-MRI) to measure apparent diffusion coefficient (ADC), fractional anisotropy (FA) and helix angle (HA). RESULTS In comparison with healthy controls, FA and transmural range of HA in MI regions showed a significant reduction whereas ADC showed a significant increment (p<0.01). The double-helix myocardial fibers shifted further to left-handed helix around the infarcted and adjacent myocardium but shifted further to right-handed helix in remote myocardium. CONCLUSION HA is sensitive to evaluate quantitatively the early changes of myocardial fibers in sub-acute MI rhesus monkeys. The myocardial fibers in normal monkeys are similar to those in normal humans, suggesting that early changes of myocardial fibers in sub-acute MI monkeys can contribute to more accurately understand those in patients suffering sub-acute MI.
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Affiliation(s)
- Yuqing Wang
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology of China, No.11 ZhongGuanCun BeiYiTiao, Beijing, 100190, China.
| | - Wei Cai
- Department of Radiology, Beijing Jishuitan Hospital, 4th clinical medical college of Peking University, No.31 Xinjiekou East Road, Beijing, China, 100035
| | - Lei Wang
- Department of Radiology, West China Hospital, Sichuan University, No.37 Guoxue Alley, Chengdu, Sichuan, China, 610041
| | - Rui Xia
- Department of Radiology, The First Affiliated Hospital, Chongqing Medical University, No.1 Friendship Road, Chongqing, China, 400016
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36
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Mohammadi S, Carey D, Dick F, Diedrichsen J, Sereno MI, Reisert M, Callaghan MF, Weiskopf N. Whole-Brain In-vivo Measurements of the Axonal G-Ratio in a Group of 37 Healthy Volunteers. Front Neurosci 2015; 9:441. [PMID: 26640427 PMCID: PMC4661323 DOI: 10.3389/fnins.2015.00441] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 11/03/2015] [Indexed: 12/13/2022] Open
Abstract
The g-ratio, quantifying the ratio between the inner and outer diameters of a fiber, is an important microstructural characteristic of fiber pathways and is functionally related to conduction velocity. We introduce a novel method for estimating the MR g-ratio non-invasively across the whole brain using high-fidelity magnetization transfer (MT) imaging and single-shell diffusion MRI. These methods enabled us to map the MR g-ratio in vivo across the brain's prominent fiber pathways in a group of 37 healthy volunteers and to estimate the inter-subject variability. Effective correction of susceptibility-related distortion artifacts was essential before combining the MT and diffusion data, in order to reduce partial volume and edge artifacts. The MR g-ratio is in good qualitative agreement with histological findings despite the different resolution and spatial coverage of MRI and histology. The MR g-ratio holds promise as an important non-invasive biomarker due to its microstructural and functional relevance in neurodegeneration.
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Affiliation(s)
- Siawoosh Mohammadi
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf Hamburg, Germany ; Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London, UK
| | - Daniel Carey
- Birkbeck/UCL Centre for NeuroImaging, Birkbeck College London, UK
| | - Fred Dick
- Birkbeck/UCL Centre for NeuroImaging, Birkbeck College London, UK
| | - Joern Diedrichsen
- UCL Institute of Cognitive Neurology, University College London London, UK
| | - Martin I Sereno
- Birkbeck/UCL Centre for NeuroImaging, Birkbeck College London, UK
| | - Marco Reisert
- Medical Physics, Department of Radiology, University Medical Center Freiburg Freiburg, Germany
| | - Martina F Callaghan
- Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London, UK
| | - Nikolaus Weiskopf
- Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London, UK ; Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences Leipzig, Germany
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Role of Diffusion Tensor MR Imaging in Degenerative Cervical Spine Disease: a Review of the Literature. Clin Neuroradiol 2015; 26:265-76. [DOI: 10.1007/s00062-015-0467-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 09/10/2015] [Indexed: 12/13/2022]
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38
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Abstract
We present an implementation of a recently developed noise reduction algorithm for dMRI data, called multi-shell position orientation adaptive smoothing (msPOAS), as a toolbox for SPM. The method intrinsically adapts to the structures of different size and shape in dMRI and hence avoids blurring typically observed in non-adaptive smoothing. We give examples for the usage of the toolbox and explain the determination of experiment-dependent parameters for an optimal performance of msPOAS.
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39
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Berl MM, Walker L, Modi P, Irfanoglu MO, Sarlls JE, Nayak A, Pierpaoli C. Investigation of vibration-induced artifact in clinical diffusion-weighted imaging of pediatric subjects. Hum Brain Mapp 2015; 36:4745-57. [PMID: 26350492 DOI: 10.1002/hbm.22846] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 05/04/2015] [Accepted: 05/08/2015] [Indexed: 11/07/2022] Open
Abstract
It has been reported that mechanical vibrations of the magnetic resonance imaging scanner could produce spurious signal dropouts in diffusion-weighted images resulting in artifactual anisotropy in certain regions of the brain with red appearance in the Directionally Encoded Color maps. We performed a review of the frequency of this artifact across pediatric studies, noting differences by scanner manufacturer, acquisition protocol, as well as weight and position of the subject. We also evaluated the ability of automated and quantitative methods to detect this artifact. We found that the artifact may be present in over 50% of data in certain protocols and is not limited to one scanner manufacturer. While a specific scanner had the highest incidence, low body weight and positioning were also associated with appearance of the artifact for both scanner types evaluated, making children potentially more susceptible than adults. Visual inspection remains the best method for artifact identification. Software for automated detection showed very low sensitivity (10%). The artifact may present inconsistently in longitudinal studies. We discuss a published case report that has been widely cited and used as evidence to set policy about diagnostic criteria for determining vegetative state. That report attributed longitudinal changes in anisotropy to white matter plasticity without considering the possibility that the changes were caused by this artifact. Our study underscores the need to check for the presence of this artifact in clinical studies, analyzes circumstances for when it may be more likely to occur, and suggests simple strategies to identify and potentially avoid its effects.
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Affiliation(s)
- Madison M Berl
- Division of Pediatric Neuropsychology, Washington, District of Columbia, Children's Research Institute, Children's National Health System, Washington, DC
| | - Lindsay Walker
- Program on Pediatric Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD
| | - Pooja Modi
- Program on Pediatric Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD
| | - M Okan Irfanoglu
- Program on Pediatric Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD.,Henry Jackson Foundation, Bethesda, Maryland
| | - Joelle E Sarlls
- NMRF, NINDS, National Institutes of Health, Bethesda, Maryland
| | - Amritha Nayak
- Program on Pediatric Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD.,Henry Jackson Foundation, Bethesda, Maryland
| | - Carlo Pierpaoli
- Program on Pediatric Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD.,Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
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40
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Tracking trauma-induced structural and functional changes above the level of spinal cord injury. Curr Opin Neurol 2015; 28:365-72. [DOI: 10.1097/wco.0000000000000224] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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41
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Magerkurth J, Mancini L, Penny W, Flandin G, Ashburner J, Micallef C, De Vita E, Daga P, White MJ, Buckley C, Yamamoto AK, Ourselin S, Yousry T, Thornton JS, Weiskopf N. Objective Bayesian fMRI analysis-a pilot study in different clinical environments. Front Neurosci 2015; 9:168. [PMID: 26029041 PMCID: PMC4428130 DOI: 10.3389/fnins.2015.00168] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 04/26/2015] [Indexed: 11/13/2022] Open
Abstract
Functional MRI (fMRI) used for neurosurgical planning delineates functionally eloquent brain areas by time-series analysis of task-induced BOLD signal changes. Commonly used frequentist statistics protect against false positive results based on a p-value threshold. In surgical planning, false negative results are equally if not more harmful, potentially masking true brain activity leading to erroneous resection of eloquent regions. Bayesian statistics provides an alternative framework, categorizing areas as activated, deactivated, non-activated or with low statistical confidence. This approach has not yet found wide clinical application partly due to the lack of a method to objectively define an effect size threshold. We implemented a Bayesian analysis framework for neurosurgical planning fMRI. It entails an automated effect-size threshold selection method for posterior probability maps accounting for inter-individual BOLD response differences, which was calibrated based on the frequentist results maps thresholded by two clinical experts. We compared Bayesian and frequentist analysis of passive-motor fMRI data from 10 healthy volunteers measured on a pre-operative 3T and an intra-operative 1.5T MRI scanner. As a clinical case study, we tested passive motor task activation in a brain tumor patient at 3T under clinical conditions. With our novel effect size threshold method, the Bayesian analysis revealed regions of all four categories in the 3T data. Activated region foci and extent were consistent with the frequentist analysis results. In the lower signal-to-noise ratio 1.5T intra-operative scanner data, Bayesian analysis provided improved brain-activation detection sensitivity compared with the frequentist analysis, albeit the spatial extents of the activations were smaller than at 3T. Bayesian analysis of fMRI data using operator-independent effect size threshold selection may improve the sensitivity and certainty of information available to guide neurosurgery.
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Affiliation(s)
- Joerg Magerkurth
- Department for Brain Repair and Rehabilitation, UCL Institute of Neurology, University College London London, UK ; Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London London, UK
| | - Laura Mancini
- Department for Brain Repair and Rehabilitation, UCL Institute of Neurology, University College London London, UK
| | - William Penny
- Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London London, UK
| | - Guillaume Flandin
- Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London London, UK
| | - John Ashburner
- Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London London, UK
| | - Caroline Micallef
- Department for Brain Repair and Rehabilitation, UCL Institute of Neurology, University College London London, UK
| | - Enrico De Vita
- Department for Brain Repair and Rehabilitation, UCL Institute of Neurology, University College London London, UK
| | - Pankaj Daga
- Centre for Medical Image Computing, University College London London, UK
| | - Mark J White
- Department for Brain Repair and Rehabilitation, UCL Institute of Neurology, University College London London, UK
| | | | - Adam K Yamamoto
- Department for Brain Repair and Rehabilitation, UCL Institute of Neurology, University College London London, UK
| | - Sebastien Ourselin
- Centre for Medical Image Computing, University College London London, UK
| | - Tarek Yousry
- Neuroradiological Academic Unit, Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, University College London London, UK
| | - John S Thornton
- Department for Brain Repair and Rehabilitation, UCL Institute of Neurology, University College London London, UK
| | - Nikolaus Weiskopf
- Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London London, UK
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42
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Neurite orientation dispersion and density imaging of the healthy cervical spinal cord in vivo. Neuroimage 2015; 111:590-601. [PMID: 25652391 DOI: 10.1016/j.neuroimage.2015.01.045] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 01/14/2015] [Accepted: 01/24/2015] [Indexed: 12/14/2022] Open
Abstract
Here we present the application of neurite orientation dispersion and density imaging (NODDI) to the healthy spinal cord in vivo. NODDI provides maps such as the intra-neurite tissue volume fraction (vin), the orientation dispersion index (ODI) and the isotropic volume fraction (viso), and here we investigate their potential for spinal cord imaging. We scanned five healthy volunteers, four of whom twice, on a 3T MRI system with a ZOOM-EPI sequence. In accordance to the published NODDI protocol, multiple b-shells were acquired at cervical level and both NODDI and diffusion tensor imaging (DTI) metrics were obtained and analysed to: i) characterise differences in grey and white matter (GM/WM); ii) assess the scan-rescan reproducibility of NODDI; iii) investigate the relationship between NODDI and DTI; and iv) compare the quality of fit of NODDI and DTI. Our results demonstrated that: i) anatomical features can be identified in NODDI maps, such as clear contrast between GM and WM in ODI; ii) the variabilities of vin and ODI are comparable to that of DTI and are driven by biological differences between subjects for ODI, have similar contribution from measurement errors and biological variation for vin, whereas viso shows higher variability, driven by measurement errors; iii) NODDI identifies potential sources contributing to DTI indices, as in the brain; and iv) NODDI outperforms DTI in terms of quality of fit. In conclusion, this work shows that NODDI is a useful model for in vivo diffusion MRI of the spinal cord, providing metrics closely related to tissue microstructure, in line with findings in the brain.
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Mohammadi S, Tabelow K, Ruthotto L, Feiweier T, Polzehl J, Weiskopf N. High-resolution diffusion kurtosis imaging at 3T enabled by advanced post-processing. Front Neurosci 2015; 8:427. [PMID: 25620906 PMCID: PMC4285740 DOI: 10.3389/fnins.2014.00427] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 12/05/2014] [Indexed: 12/13/2022] Open
Abstract
Diffusion Kurtosis Imaging (DKI) is more sensitive to microstructural differences and can be related to more specific micro-scale metrics (e.g., intra-axonal volume fraction) than diffusion tensor imaging (DTI), offering exceptional potential for clinical diagnosis and research into the white and gray matter. Currently DKI is acquired only at low spatial resolution (2–3 mm isotropic), because of the lower signal-to-noise ratio (SNR) and higher artifact level associated with the technically more demanding DKI. Higher spatial resolution of about 1 mm is required for the characterization of fine white matter pathways or cortical microstructure. We used restricted-field-of-view (rFoV) imaging in combination with advanced post-processing methods to enable unprecedented high-quality, high-resolution DKI (1.2 mm isotropic) on a clinical 3T scanner. Post-processing was advanced by developing a novel method for Retrospective Eddy current and Motion ArtifacT Correction in High-resolution, multi-shell diffusion data (REMATCH). Furthermore, we applied a powerful edge preserving denoising method, denoted as multi-shell orientation-position-adaptive smoothing (msPOAS). We demonstrated the feasibility of high-quality, high-resolution DKI and its potential for delineating highly myelinated fiber pathways in the motor cortex. REMATCH performs robustly even at the low SNR level of high-resolution DKI, where standard EC and motion correction failed (i.e., produced incorrectly aligned images) and thus biased the diffusion model fit. We showed that the combination of REMATCH and msPOAS increased the contrast between gray and white matter in mean kurtosis (MK) maps by about 35% and at the same time preserves the original distribution of MK values, whereas standard Gaussian smoothing strongly biases the distribution.
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Affiliation(s)
- Siawoosh Mohammadi
- Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London London, UK ; Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf Hamburg, Germany
| | - Karsten Tabelow
- Stochastic Algorithms and Nonparametric Statistics, Weierstrass Institute for Applied Analysis and Stochastics Berlin, Germany
| | - Lars Ruthotto
- Department of Earth, Ocean and Atmospheric Sciences, The University of British Columbia Vancouver, BC, Canada
| | | | - Jörg Polzehl
- Stochastic Algorithms and Nonparametric Statistics, Weierstrass Institute for Applied Analysis and Stochastics Berlin, Germany
| | - Nikolaus Weiskopf
- Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London London, UK
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Weiskopf N, Callaghan MF, Josephs O, Lutti A, Mohammadi S. Estimating the apparent transverse relaxation time (R2(*)) from images with different contrasts (ESTATICS) reduces motion artifacts. Front Neurosci 2014; 8:278. [PMID: 25309307 PMCID: PMC4159978 DOI: 10.3389/fnins.2014.00278] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 08/18/2014] [Indexed: 12/26/2022] Open
Abstract
Relaxation rates provide important information about tissue microstructure. Multi-parameter mapping (MPM) estimates multiple relaxation parameters from multi-echo FLASH acquisitions with different basic contrasts, i.e., proton density (PD), T1 or magnetization transfer (MT) weighting. Motion can particularly affect maps of the apparent transverse relaxation rate R2*, which are derived from the signal of PD-weighted images acquired at different echo times. To address the motion artifacts, we introduce ESTATICS, which robustly estimates R2* from images even when acquired with different basic contrasts. ESTATICS extends the fitted signal model to account for inherent contrast differences in the PDw, T1w and MTw images. The fit was implemented as a conventional ordinary least squares optimization and as a robust fit with a small or large confidence interval. These three different implementations of ESTATICS were tested on data affected by severe motion artifacts and data with no prominent motion artifacts as determined by visual assessment or fast optical motion tracking. ESTATICS improved the quality of the R2* maps and reduced the coefficient of variation for both types of data—with average reductions of 30% when severe motion artifacts were present. ESTATICS can be applied to any protocol comprised of multiple 2D/3D multi-echo FLASH acquisitions as used in the general research and clinical setting.
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Affiliation(s)
- Nikolaus Weiskopf
- Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London London, UK
| | - Martina F Callaghan
- Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London London, UK
| | - Oliver Josephs
- Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London London, UK ; Birkbeck-UCL Centre for NeuroImaging London, UK
| | - Antoine Lutti
- Laboratoire de Recherche en Neuroimagerie, Department of Clinical Neurosciences, Centre Hospitalier Universitaire Vaudois Lausanne, Switzerland
| | - Siawoosh Mohammadi
- Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London London, UK
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Lin E, Long H, Li G, Lei W. Does diffusion tensor data reflect pathological changes in the spinal cord with chronic injury. Neural Regen Res 2014; 8:3382-90. [PMID: 25206660 PMCID: PMC4146007 DOI: 10.3969/j.issn.1673-5374.2013.36.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 11/17/2013] [Indexed: 11/29/2022] Open
Abstract
Magnetic resonance diffusion tensor imaging has been shown to quantitatively measure the early pathological changes in chronic cervical spondylotic myelopathy. In this study, a novel spongy polyurethane material was implanted in the rat C3–5 epidural space to establish a rat model of chronic cervical spondylotic myelopathy. Diffusion tensor data were used to predict pathological changes. Results revealed that the fractional anisotropy value gradually decreased at 4, 24, and 72 hours and 1 week after injury in rat spinal cord, showing a time-dependent manner. Average diffusion coefficient increased at 72 hours and 1 week after implantation. Hematoxylin-eosin staining and Luxol-fast-blue staining exhibited that the number of neurons in the anterior horn of the spinal cord gray matter and the nerve fiber density of the white matter gradually reduced with prolonged compression time. Neuronal loss was most significant at 1 week after injury. Results verified that the fractional anisotropy value and average diffusion coefficient reflected the degree of pathological change in the site of compression in rat models at various time points after chronic spinal cord compression injury, which potentially has a reference value in the early diagnosis of chronic cervical spondylotic myelopathy.
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Affiliation(s)
- Erjian Lin
- Department of Radiology, the Eastern Hospital of the First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510700, Guangdong Province, China
| | - Houqing Long
- Department of Spinal Surgery, Huangpu Branch, First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510700, Guangdong Province, China
| | - Guangsheng Li
- Department of Orthopedics, Affiliated Hospital of Guangdong Medical College, Zhanjiang 524001, Guangdong Province, China
| | - Wanlong Lei
- Department of Human Anatomy and Histoembryology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510086, Guangdong Province, China
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Toosy AT, Kou N, Altmann D, Wheeler-Kingshott CAM, Thompson AJ, Ciccarelli O. Voxel-based cervical spinal cord mapping of diffusion abnormalities in MS-related myelitis. Neurology 2014; 83:1321-5. [PMID: 25186861 DOI: 10.1212/wnl.0000000000000857] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To apply a novel postprocessing voxel-based analysis for diffusion tensor imaging of the cervical spinal cord in multiple sclerosis (MS) in a prospective cross-sectional study. METHODS Fourteen patients with MS who were within 4 weeks of the onset of cervical myelitis (lesion C1-3) and 11 healthy controls underwent cervical spinal cord diffusion tensor imaging. Cervical spinal cord maps of fractional anisotropy (FA), mean diffusivity, radial diffusivity (RD), and axial diffusivity were registered and compared between patients and controls. Mean FA and RD values from significant thresholded clusters were regressed with clinical scores, after adjusting for cord area and age, to determine associations with physical disability. RESULTS Cord registrations for subjects were qualitatively assessed (scored out of 5) and those with low scores (1 or 2) were excluded from further analysis. Cord registration was considered good in 11 patients (6 females; mean age = 35.5 years) and 10 controls (6 females; mean age 44 years). Voxel-based comparisons showed patients with MS had lower FA and higher RD at C2-3 levels (left >right mainly in gray matter; p < 0.01, uncorrected). Extracted values of both FA and RD from thresholded clusters were significantly associated with greater disability measured using the Expanded Disability Status Scale and Timed 25-Foot Walk Test in patients with MS. CONCLUSIONS Mapping diffusion abnormalities within the cervical spinal cord using a novel voxel-based approach can localize clinically relevant pathology.
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Affiliation(s)
- Ahmed T Toosy
- From the Departments of Brain Repair and Rehabilitation (A.T.T., N.K., A.J.T., O.C.) and Neuroinflammation (D.A., C.A.M.W.-K.), NMR Research Unit, Queen Square MS Centre, UCL Institute of Neurology, University College London; Institute of Cognitive Neuroscience (N.K.) and NIHR UCL-UCLH Biomedical Research Centre (BRC) (A.J.T., O.C.), University College London, Queen Square; and Medical Statistics Department (D.A.), London School of Hygiene and Tropical Medicine, UK.
| | - Nancy Kou
- From the Departments of Brain Repair and Rehabilitation (A.T.T., N.K., A.J.T., O.C.) and Neuroinflammation (D.A., C.A.M.W.-K.), NMR Research Unit, Queen Square MS Centre, UCL Institute of Neurology, University College London; Institute of Cognitive Neuroscience (N.K.) and NIHR UCL-UCLH Biomedical Research Centre (BRC) (A.J.T., O.C.), University College London, Queen Square; and Medical Statistics Department (D.A.), London School of Hygiene and Tropical Medicine, UK
| | - Daniel Altmann
- From the Departments of Brain Repair and Rehabilitation (A.T.T., N.K., A.J.T., O.C.) and Neuroinflammation (D.A., C.A.M.W.-K.), NMR Research Unit, Queen Square MS Centre, UCL Institute of Neurology, University College London; Institute of Cognitive Neuroscience (N.K.) and NIHR UCL-UCLH Biomedical Research Centre (BRC) (A.J.T., O.C.), University College London, Queen Square; and Medical Statistics Department (D.A.), London School of Hygiene and Tropical Medicine, UK
| | - Claudia A M Wheeler-Kingshott
- From the Departments of Brain Repair and Rehabilitation (A.T.T., N.K., A.J.T., O.C.) and Neuroinflammation (D.A., C.A.M.W.-K.), NMR Research Unit, Queen Square MS Centre, UCL Institute of Neurology, University College London; Institute of Cognitive Neuroscience (N.K.) and NIHR UCL-UCLH Biomedical Research Centre (BRC) (A.J.T., O.C.), University College London, Queen Square; and Medical Statistics Department (D.A.), London School of Hygiene and Tropical Medicine, UK
| | - Alan J Thompson
- From the Departments of Brain Repair and Rehabilitation (A.T.T., N.K., A.J.T., O.C.) and Neuroinflammation (D.A., C.A.M.W.-K.), NMR Research Unit, Queen Square MS Centre, UCL Institute of Neurology, University College London; Institute of Cognitive Neuroscience (N.K.) and NIHR UCL-UCLH Biomedical Research Centre (BRC) (A.J.T., O.C.), University College London, Queen Square; and Medical Statistics Department (D.A.), London School of Hygiene and Tropical Medicine, UK
| | - Olga Ciccarelli
- From the Departments of Brain Repair and Rehabilitation (A.T.T., N.K., A.J.T., O.C.) and Neuroinflammation (D.A., C.A.M.W.-K.), NMR Research Unit, Queen Square MS Centre, UCL Institute of Neurology, University College London; Institute of Cognitive Neuroscience (N.K.) and NIHR UCL-UCLH Biomedical Research Centre (BRC) (A.J.T., O.C.), University College London, Queen Square; and Medical Statistics Department (D.A.), London School of Hygiene and Tropical Medicine, UK
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Kong Y, Shi L, Hui SCN, Wang D, Deng M, Chu WCW, Cheng JCY. Variation in anisotropy and diffusivity along the medulla oblongata and the whole spinal cord in adolescent idiopathic scoliosis: a pilot study using diffusion tensor imaging. AJNR Am J Neuroradiol 2014; 35:1621-7. [PMID: 24788126 DOI: 10.3174/ajnr.a3912] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND AND PURPOSE Disturbed somatosensory evoked potentials have been demonstrated in patients with adolescent idiopathic scoliosis (but this functional delay was found to originate above the C5-6 level, while the lower cord level was unaffected). Together with MR imaging observation of tonsillar ectopia and a relatively tethered cord, we hypothesized that there is disturbed mean diffusivity integrity along the spinal cord. In this study, advanced DTI was used to evaluate whether there was underlying decreased WM integrity within the brain stem and spinal cord in adolescent idiopathic scoliosis and any relationship to cerebellar tonsillar ectopia. Clinical impact on balance testing was also correlated. MATERIALS AND METHODS Thirteen girls with adolescent idiopathic scoliosis with right thoracic curves were compared with 13 age-matched healthy girls. DTI of the brain and whole spinal cord was performed. ROIs were manually defined for the medulla oblongata and along each intervertebral segment of the cord. Mean values of fractional anisotropy and mean diffusivity were computed at the defined regions. Between-group comparisons were performed by 1-way ANOVA. RESULTS Significantly decreased fractional anisotropy values and increased mean diffusivity values were found at the medulla oblongata and C1-2, C2-3, C3-4, and C4-5 segments in patients with adolescent idiopathic scoliosis compared with healthy subjects. No significant difference was found in the lower cord levels. Significant correlation was found between the tonsillar level and fractional anisotropy value at the C4-5 level in patients with adolescent idiopathic scoliosis only. CONCLUSIONS The findings from this study are in agreement with previous findings showing abnormal somatosensory evoked potential readings occurring only above the C5-6 level in patients with adolescent idiopathic scoliosis; these findings might partially explain the pathophysiology of the neural pathway involved.
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Affiliation(s)
- Y Kong
- From the Departments of Imaging and Interventional Radiology (Y.K., L.S., S.C.N.H., D.W., M.D., W.C.W.C.)
| | - L Shi
- From the Departments of Imaging and Interventional Radiology (Y.K., L.S., S.C.N.H., D.W., M.D., W.C.W.C.)Shenzhen Institutes of Advanced Technology (L.S.), Chinese Academy of Sciences, Shenzhen, China
| | - S C N Hui
- From the Departments of Imaging and Interventional Radiology (Y.K., L.S., S.C.N.H., D.W., M.D., W.C.W.C.)
| | - D Wang
- From the Departments of Imaging and Interventional Radiology (Y.K., L.S., S.C.N.H., D.W., M.D., W.C.W.C.)Biomedical Engineering and Shun Hing Institute of Advanced Engineering (D.W.)The Chinese University of Hong Kong Shenzhen Research Institute (D.W.), Shenzhen, China.
| | - M Deng
- From the Departments of Imaging and Interventional Radiology (Y.K., L.S., S.C.N.H., D.W., M.D., W.C.W.C.)
| | - W C W Chu
- From the Departments of Imaging and Interventional Radiology (Y.K., L.S., S.C.N.H., D.W., M.D., W.C.W.C.)
| | - J C Y Cheng
- Orthopaedics and Traumatology (J.C.Y.C.), The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
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Middleton DM, Mohamed FB, Barakat N, Hunter LN, Shellikeri S, Finsterbusch J, Faro SH, Shah P, Samdani AF, Mulcahey M. An investigation of motion correction algorithms for pediatric spinal cord DTI in healthy subjects and patients with spinal cord injury. Magn Reson Imaging 2014; 32:433-9. [DOI: 10.1016/j.mri.2014.01.020] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2013] [Revised: 01/25/2014] [Accepted: 01/27/2014] [Indexed: 11/27/2022]
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Becker SMA, Tabelow K, Mohammadi S, Weiskopf N, Polzehl J. Adaptive smoothing of multi-shell diffusion weighted magnetic resonance data by msPOAS. Neuroimage 2014; 95:90-105. [PMID: 24680711 PMCID: PMC4073655 DOI: 10.1016/j.neuroimage.2014.03.053] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 01/06/2014] [Accepted: 03/18/2014] [Indexed: 11/08/2022] Open
Abstract
We present a novel multi-shell position-orientation adaptive smoothing (msPOAS) method for diffusion weighted magnetic resonance data. Smoothing in voxel and diffusion gradient space is embedded in an iterative adaptive multiscale approach. The adaptive character avoids blurring of the inherent structures and preserves discontinuities. The simultaneous treatment of all q-shells improves the stability compared to single-shell approaches such as the original POAS method. The msPOAS implementation simplifies and speeds up calculations, compared to POAS, facilitating its practical application. Simulations and heuristics support the face validity of the technique and its rigorousness. The characteristics of msPOAS were evaluated on single and multi-shell diffusion data of the human brain. Significant reduction in noise while preserving the fine structure was demonstrated for diffusion weighted images, standard DTI analysis and advanced diffusion models such as NODDI. MsPOAS effectively improves the poor signal-to-noise ratio in highly diffusion weighted multi-shell diffusion data, which is required by recent advanced diffusion micro-structure models. We demonstrate the superiority of the new method compared to other advanced denoising methods. Method for structure preserving smoothing multi-shell dMRI data Does not rely on any dMRI diffusion model Outperforms naive single-shell POAS and other approaches Feasible for real data application Implemented within a freely available package dti for the R Language
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Affiliation(s)
- S M A Becker
- Weierstrass Institute for Applied Analysis and Stochastics, Berlin, Germany
| | - K Tabelow
- Weierstrass Institute for Applied Analysis and Stochastics, Berlin, Germany.
| | - S Mohammadi
- Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, London, United Kingdom
| | - N Weiskopf
- Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, London, United Kingdom
| | - J Polzehl
- Weierstrass Institute for Applied Analysis and Stochastics, Berlin, Germany
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Using high angular resolution diffusion imaging data to discriminate cortical regions. PLoS One 2013; 8:e63842. [PMID: 23691102 PMCID: PMC3656939 DOI: 10.1371/journal.pone.0063842] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Accepted: 04/08/2013] [Indexed: 11/19/2022] Open
Abstract
Brodmann’s 100–year–old summary map has been widely used for cortical localization in neuroscience. There is a pressing need to update this map using non–invasive, high–resolution and reproducible data, in a way that captures individual variability. We demonstrate here that standard HARDI data has sufficiently diverse directional variation among grey matter regions to inform parcellation into distinct functional regions, and that this variation is reproducible across scans. This characterization of the signal variation as non–random and reproducible is the critical condition for successful cortical parcellation using HARDI data. This paper is a first step towards an individual cortex–wide map of grey matter microstructure, The gray/white matter and pial boundaries were identified on the high–resolution structural MRI images. Two HARDI data sets were collected from each individual and aligned with the corresponding structural image. At each vertex point on the surface tessellation, the diffusion–weighted signal was extracted from each image in the HARDI data set at a point, half way between gray/white matter and pial boundaries. We then derived several features of the HARDI profile with respect to the local cortical normal direction, as well as several fully orientationally invariant features. These features were taken as a fingerprint of the underlying grey matter tissue, and used to distinguish separate cortical areas. A support–vector machine classifier, trained on three distinct areas in repeat 1 achieved 80–82% correct classification of the same three areas in the unseen data from repeat 2 in three volunteers. Though gray matter anisotropy has been mostly overlooked hitherto, this approach may eventually form the foundation of a new cortical parcellation method in living humans. Our approach allows for further studies on the consistency of HARDI based parcellation across subjects and comparison with independent microstructural measures such as ex–vivo histology.
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