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Powers JM, Ioachim G, Stroman PW. Ten Key Insights into the Use of Spinal Cord fMRI. Brain Sci 2018; 8:E173. [PMID: 30201938 PMCID: PMC6162663 DOI: 10.3390/brainsci8090173] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 08/29/2018] [Accepted: 09/06/2018] [Indexed: 01/27/2023] Open
Abstract
A comprehensive review of the literature-to-date on functional magnetic resonance imaging (fMRI) of the spinal cord is presented. Spinal fMRI has been shown, over more than two decades of work, to be a reliable tool for detecting neural activity. We discuss 10 key points regarding the history, development, methods, and applications of spinal fMRI. Animal models have served a key purpose for the development of spinal fMRI protocols and for experimental spinal cord injury studies. Applications of spinal fMRI span from animal models across healthy and patient populations in humans using both task-based and resting-state paradigms. The literature also demonstrates clear trends in study design and acquisition methods, as the majority of studies follow a task-based, block design paradigm, and utilize variations of single-shot fast spin-echo imaging methods. We, therefore, discuss the similarities and differences of these to resting-state fMRI and gradient-echo EPI protocols. Although it is newly emerging, complex connectivity and network analysis is not only possible, but has also been shown to be reliable and reproducible in the spinal cord for both task-based and resting-state studies. Despite the technical challenges associated with spinal fMRI, this review identifies reliable solutions that have been developed to overcome these challenges.
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Affiliation(s)
- Jocelyn M Powers
- Centre for Neuroscience Studies, Queen's University, Kingston, ON K7L 3N6, Canada.
| | - Gabriela Ioachim
- Centre for Neuroscience Studies, Queen's University, Kingston, ON K7L 3N6, Canada.
| | - Patrick W Stroman
- Centre for Neuroscience Studies, Queen's University, Kingston, ON K7L 3N6, Canada.
- Department of Biomedical Sciences, Queen's University, Kingston, ON K7L 3N6, Canada.
- Department of Physics, Queen's University, Kingston, ON K7L 3N6, Canada.
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Paquette T, Jeffrey-Gauthier R, Leblond H, PichÉ M. Functional Neuroimaging of Nociceptive and Pain-Related Activity in the Spinal Cord and Brain: Insights From Neurovascular Coupling Studies. Anat Rec (Hoboken) 2018; 301:1585-1595. [PMID: 29752872 DOI: 10.1002/ar.23854] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 03/22/2018] [Accepted: 03/31/2018] [Indexed: 12/12/2022]
Abstract
Spinal cord and brain processes underlie pain perception, which produces systemic cardiovascular changes. In turn, the autonomic nervous system regulates vascular function in the spinal cord and brain in order to adapt to these systemic changes, while neuronal activity induces local vascular changes. Thus, autonomic regulation and pain processes in the brain and spinal cord are tightly linked and interrelated. The objective of this topical review is to discuss work on neurovascular coupling during nociceptive processing in order to highlight supporting evidence and limitations for the use of cerebral and spinal fMRI to investigate pain mechanisms and spinal nociceptive processes. Work on functional neuroimaging of pain is presented and discussed in relation to available neurovascular coupling studies and related issues. Perspectives on future work are also discussed with an emphasis on differences between the brain and the spinal cord and on different approaches that may be useful to improve current methods, data analyses and interpretation. In summary, this review highlights the lack of data on neurovascular coupling during nociceptive stimulation and indicates that hemodynamic and BOLD responses measured with fMRI may be biased by nonspecific vascular changes. Future neuroimaging studies on nociceptive and pain-related processes would gain further understanding of neurovascular coupling in the brain and spinal cord and should take into account the effects of systemic vascular changes that may affect hemodynamic responses. Anat Rec, 301:1585-1595, 2018. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Thierry Paquette
- Department of Chiropractic, Université du Québec à Trois-Rivières, Trois-Rivières, Canada.,CogNAC Research Group, Université du Québec à Trois-Rivières, Trois-Rivières, Canada.,Department of Anatomy, Université du Québec à Trois-Rivières, Trois-Rivières, QC, Canada
| | - Renaud Jeffrey-Gauthier
- Department of Chiropractic, Université du Québec à Trois-Rivières, Trois-Rivières, Canada.,CogNAC Research Group, Université du Québec à Trois-Rivières, Trois-Rivières, Canada.,Department of Anatomy, Université du Québec à Trois-Rivières, Trois-Rivières, QC, Canada
| | - Hugues Leblond
- CogNAC Research Group, Université du Québec à Trois-Rivières, Trois-Rivières, Canada.,Department of Anatomy, Université du Québec à Trois-Rivières, Trois-Rivières, QC, Canada
| | - Mathieu PichÉ
- Department of Chiropractic, Université du Québec à Trois-Rivières, Trois-Rivières, Canada.,CogNAC Research Group, Université du Québec à Trois-Rivières, Trois-Rivières, Canada
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Zhong XP, Chen YX, Li ZY, Shen ZW, Kong KM, Wu RH. Cervical spinal functional magnetic resonance imaging of the spinal cord injured patient during electrical stimulation. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2017; 26:71-77. [PMID: 27311305 DOI: 10.1007/s00586-016-4646-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 05/31/2016] [Accepted: 06/01/2016] [Indexed: 02/05/2023]
Abstract
PURPOSE To evaluate the spatial distribution and signal intensity changes following spinal cord activation in patients with spinal cord injury. METHODS This study used spinal functional magnetic resonance imaging (fMRI) based on signal enhancement by extra-vascular water protons (SEEP) to assess elicited responses during subcutaneous electrical stimulation at the right elbow and right thumb in the cervical spinal cord. RESULTS Seven healthy volunteers and seven patients with cervical spinal cord injury (SCI) were included in this study. Significant functional activation was observed mainly in the right side of the spinal cord at the level of the C5-C6 cervical vertebra in both the axial and sagittal planes. A higher percentage of signal changes (4.66 ± 2.08 % in injured subjects vs. 2.78 ± 1.66 % in normal) and more average activation voxels (4.69 ± 2.59 in injured subjects vs. 2.56 ± 1.13 in normal subject) in axial plane at the C5-C6 cervical vertebra with a statistically significant difference. The same trends were observed in the sagittal plane with higher percentage of signal changes and more average activation voxels, though no statistically significant difference compared with the control group. CONCLUSIONS Spinal SEEP fMRI is a powerful noninvasive method for the study of local neuronal activation in the human spinal cord, which may be of clinical value for evaluating the effectiveness of interventions aimed at promoting recovery of function using electrical stimulation.
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Affiliation(s)
- Xiao-Ping Zhong
- Department of Surgery, 2nd Affiliated Hospital of Shantou University Medical College, Shantou, 515041, Guangdong, China
| | - Ye-Xi Chen
- Department of Surgery, 2nd Affiliated Hospital of Shantou University Medical College, Shantou, 515041, Guangdong, China.
| | - Zhi-Yang Li
- Department of Surgery, 2nd Affiliated Hospital of Shantou University Medical College, Shantou, 515041, Guangdong, China
| | - Zhi-Wei Shen
- Department of Medical Imaging, 2nd Affiliated Hospital of Shantou University Medical College, Shantou, 515041, Guangdong, China.
| | - Kang-Mei Kong
- Department of Surgery, 2nd Affiliated Hospital of Shantou University Medical College, Shantou, 515041, Guangdong, China
| | - Ren-Hua Wu
- Department of Medical Imaging, 2nd Affiliated Hospital of Shantou University Medical College, Shantou, 515041, Guangdong, China
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Wheeler-Kingshott CA, Stroman PW, Schwab JM, Bacon M, Bosma R, Brooks J, Cadotte DW, Carlstedt T, Ciccarelli O, Cohen-Adad J, Curt A, Evangelou N, Fehlings MG, Filippi M, Kelley BJ, Kollias S, Mackay A, Porro CA, Smith S, Strittmatter SM, Summers P, Thompson AJ, Tracey I. The current state-of-the-art of spinal cord imaging: applications. Neuroimage 2013; 84:1082-93. [PMID: 23859923 DOI: 10.1016/j.neuroimage.2013.07.014] [Citation(s) in RCA: 155] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2013] [Revised: 06/30/2013] [Accepted: 07/04/2013] [Indexed: 12/14/2022] Open
Abstract
A first-ever spinal cord imaging meeting was sponsored by the International Spinal Research Trust and the Wings for Life Foundation with the aim of identifying the current state-of-the-art of spinal cord imaging, the current greatest challenges, and greatest needs for future development. This meeting was attended by a small group of invited experts spanning all aspects of spinal cord imaging from basic research to clinical practice. The greatest current challenges for spinal cord imaging were identified as arising from the imaging environment itself; difficult imaging environment created by the bone surrounding the spinal canal, physiological motion of the cord and adjacent tissues, and small crosssectional dimensions of the spinal cord, exacerbated by metallic implants often present in injured patients. Challenges were also identified as a result of a lack of "critical mass" of researchers taking on the development of spinal cord imaging, affecting both the rate of progress in the field, and the demand for equipment and software to manufacturers to produce the necessary tools. Here we define the current state-of-the-art of spinal cord imaging, discuss the underlying theory and challenges, and present the evidence for the current and potential power of these methods. In two review papers (part I and part II), we propose that the challenges can be overcome with advances in methods, improving availability and effectiveness of methods, and linking existing researchers to create the necessary scientific and clinical network to advance the rate of progress and impact of the research.
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Affiliation(s)
- C A Wheeler-Kingshott
- NMR Research Unit, Queen Square MS Centre, UCL Institute of Neurology, London, England, UK.
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Reduction of physiological noise with independent component analysis improves the detection of nociceptive responses with fMRI of the human spinal cord. Neuroimage 2012; 63:245-52. [PMID: 22776463 DOI: 10.1016/j.neuroimage.2012.06.057] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Revised: 06/22/2012] [Accepted: 06/23/2012] [Indexed: 11/20/2022] Open
Abstract
The evaluation of spinal cord neuronal activity in humans with functional magnetic resonance imaging (fMRI) is technically challenging. Major difficulties arise from cardiac and respiratory movement artifacts that constitute significant sources of noise. In this paper we assessed the Correction of Structured noise using spatial Independent Component Analysis (CORSICA). FMRI data of the cervical spinal cord were acquired in 14 healthy subjects using gradient-echo EPI. Nociceptive electrical stimuli were applied to the thumb. Additional data with short TR (250 ms, to prevent aliasing) were acquired to generate a spatial map of physiological noise derived from Independent Component Analysis (ICA). Physiological noise was subsequently removed from the long-TR data after selecting independent components based on the generated noise map. Stimulus-evoked responses were analyzed using the general linear model, with and without CORSICA and with a regressor generated from the cerebrospinal fluid region. Results showed higher sensitivity to detect stimulus-related activation in the targeted dorsal segment of the cord after CORSICA. Furthermore, fewer voxels showed stimulus-related signal changes in the CSF and outside the spinal region, suggesting an increase in specificity. ICA can be used to effectively reduce physiological noise in spinal cord fMRI time series.
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Abstract
Different MR techniques, such as relaxation times, diffusion, perfusion, and spectroscopy have been employed to study rodent spinal cord. In this chapter, a description of these methods is given, along with examples of normal metrics that can be derived from the MR acquisitions, as well as examples of applications to pathology.
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Affiliation(s)
- Virginie Callot
- Centre de Résonance Magnétique Biologique et Médicale (CRMBM), UMR 6612, CNRS, Université de la Méditerranée, 13385 Marseille Cedex 05, France.
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Malisza KL, Jones C, Gruwel MLH, Foreman D, Fernyhough P, Calcutt NA. Functional magnetic resonance imaging of the spinal cord during sensory stimulation in diabetic rats. J Magn Reson Imaging 2009; 30:271-6. [PMID: 19629995 DOI: 10.1002/jmri.21856] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
PURPOSE To determine if differences exist between control and diabetic rats in functional magnetic resonance imaging (fMRI) activity of the spinal cord and if fMRI can provide a means of early detection of diabetic neuropathy. MATERIALS AND METHODS fMRI of the spinal cord, using noxious electrical stimulation (15 V ( approximately 8 mA), 0.3 msec, 3 Hz) of the hind paw, was performed in groups of control and streptozotocin (STZ)-induced type 1 diabetic rats. RESULTS Diabetic rats were lighter, hyperglycemic, and had lower blood pH than controls. fMRI activity at the lumbar enlargement of the spinal cord was identified in the dorsal horn ipsilateral to stimulus of all animals. Signal intensity changes across the lumbar spinal cord during periods of activity were not significantly different between control and diabetic rats, with a trend toward greater signal changes in controls. When specific regions of the spinal cord were analyzed, control rats exhibited significantly increased blood-oxygen level-dependent (BOLD) fMRI activity in both ipsilateral and contralateral dorsal horn compared to diabetic rats. CONCLUSION The results of this study are consistent with reports that primary afferent input to the spinal cord is diminished by diabetes, and suggest that BOLD fMRI may be useful in early detection of diabetic neuropathy.
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Affiliation(s)
- Krisztina L Malisza
- National Research Council, Institute for Biodiagnostics, Winnipeg, MB, Canada.
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Hu TT, Laeremans A, Eysel UT, Cnops L, Arckens L. Analysis of c-fos and zif268 expression reveals time-dependent changes in activity inside and outside the lesion projection zone in adult cat area 17 after retinal lesions. Cereb Cortex 2009; 19:2982-92. [PMID: 19386633 DOI: 10.1093/cercor/bhp069] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Retinal lesions induce a topographic reorganization in the corresponding lesion projection zone (LPZ) in the visual cortex of adult cats. To gain a better insight into the reactivation dynamics, we investigated the alterations in cortical activity throughout area 17. We implemented in situ hybridization and real-time polymerase chain reaction to analyze the spatiotemporal expression patterns of the activity marker genes zif268 and c-fos. The immediate early gene (IEG) data confirmed a strong and permanent activity decrease in the center of the LPZ as previously described by electrophysiology. A recovery of IEG expression was clearly measured in the border of the LPZ. We were able to register reorganization over 2.5-6 mm. We also present evidence that the central retinal lesions concomitantly influence the activity in far peripheral parts of area 17. Its IEG expression levels appeared dependent of time and distance from the LPZ. We therefore propose that coupled changes in activity occur inside and outside the LPZ. In conclusion, alterations in activity reporter gene expression throughout area 17 contribute to the lesion-induced functional reorganization.
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Affiliation(s)
- Tjing-Tjing Hu
- Laboratory of Neuroplasticity and Neuroproteomics, Katholieke Universiteit Leuven, B-3000 Leuven, Belgium
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Majcher K, Tomanek B, Tuor UI, Jasinski A, Foniok T, Rushforth D, Hess G. Functional magnetic resonance imaging within the rat spinal cord following peripheral nerve injury. Neuroimage 2007; 38:669-76. [PMID: 17904387 DOI: 10.1016/j.neuroimage.2007.08.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2007] [Revised: 07/31/2007] [Accepted: 08/06/2007] [Indexed: 11/20/2022] Open
Abstract
Functional magnetic resonance imaging (fMRI) was used to detect the effects of graded peripheral nerve injury at the spinal level. Graded peripheral nerve injury in rats was accomplished by transection of nerves entering the spinal cord at the L3 and L4 levels of the spinal cord segments. Electrical stimulation of the hindpaw was used to elicit activity within the spinal cord. The stimulation experimental paradigm consisted of 62 functional images, 5 slices each, with a total of 3 rest and 2 stimulation periods. A 9.4 T MRI system and a quadrature volume rf coil covering the lumbar spinal cord were used for the fMRI study. Sets of fast spin echo images were acquired repeatedly following sham preparatory surgery under control conditions and in rats following sham surgery (pre nerve cut), followed by L3 nerve and then L4 nerve section. In rats with sham surgery, there was a significant activation within the dorsal horn of slices corresponding to L3 and L4 spinal cord segments. Following section of the L3 nerve, there was a reduction in the number of active voxels in the L3 and L4 spinal cord segments. The activation was reduced further by sectioning of the L4 nerve. Thus, following an increasing loss of axonal connections to the spinal cord, there was a decreasing number of active voxels within the spinal cord. The results demonstrate that spinal fMRI in the rat has sufficient sensitivity to detect within the spinal cord the effects of a graded reduction in peripheral connectivity.
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Affiliation(s)
- Katarzyna Majcher
- Institute of Nuclear Physics, Polish Academy of Sciences, Krakow, Poland
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Endo T, Spenger C, Westman E, Tominaga T, Olson L. Reorganization of sensory processing below the level of spinal cord injury as revealed by fMRI. Exp Neurol 2007; 209:155-60. [PMID: 17988666 DOI: 10.1016/j.expneurol.2007.09.017] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Revised: 08/31/2007] [Accepted: 09/11/2007] [Indexed: 10/22/2022]
Abstract
The adult mammalian CNS undergoes plastic changes in response to injury. To investigate such changes in spinal cord, functional magnetic resonance imaging (fMRI) was applied in rats subjected to complete transection of the mid-thoracic spinal cord. Blood oxygenation level-dependent (BOLD) contrasts were recorded in the distal spinal cord different times after injury (3, 7, and 14 days, and 1, 3, and 6 months) in response to electrical hind limb stimulation. Functional MRI demonstrated a substantial increase of neuronal activation in the ipsilateral dorsal horn after injury. Notably, 0.5 mA, which did not evoke activation in the normal spinal cord and was considered a non-painful stimulus, induced significant BOLD responses in the dorsal horn after injury. Increased sensitivity was also seen in response to 1.0 mA stimulation. Our results suggest exaggerated responsiveness of spinal neurons after spinal cord injury. Reorganization in the injured spinal cord has been shown to involve the amplification of peripheral inputs and implicated as one underlying mechanism causing neuropathic pain and autonomic dysreflexia. Since BOLD signals can demonstrate such plastic changes in spinal cord parenchyma, we propose fMRI as a method to monitor functional reorganization in the spinal cord after injury. Combining brain and spinal cord fMRI allows the visualization of neuronal activities along the entire neuroaxis and thereby an evaluation of the different plastic responses to CNS injuries that occur in the brain and the spinal cord.
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Affiliation(s)
- Toshiki Endo
- Department of Neuroscience, Karolinska Institutet, 17177, Stockholm, Sweden.
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Lawrence J, Stroman PW, Malisza KL. Functional MRI of the cervical spinal cord during noxious and innocuous thermal stimulation in the alpha-chloralose- and halothane-anesthetized rat. Magn Reson Imaging 2007; 26:1-10. [PMID: 17587529 DOI: 10.1016/j.mri.2007.05.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2006] [Revised: 04/30/2007] [Accepted: 05/01/2007] [Indexed: 11/19/2022]
Abstract
Patterns of neuronal activity in the spinal cord using functional magnetic resonance imaging during noxious (48 degrees C) and innocuous (40 degrees C) thermal stimulation of the rat forepaw were examined. The patterns of functional activity elicited by thermal stimuli were compared in alpha-chloralose- and halothane-anesthetized rats. Although the locations of active pixels were similar during both types of stimulation, the mean percentage signal change was higher during noxious stimulation in both anesthetic groups. Ipsilateral dorsal horn activity was evident during both noxious and innocuous stimulation in all animals. The greatest consistency of ipsilateral dorsal horn activity occurred at the C3 to C5 spinal cord segments in all groups. Consistent contralateral dorsal horn activity appeared in segments C6 to C8 in all groups. C-fos immunohistochemical staining confirmed the presence of neural activity in the spinal cords of all animals.
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Affiliation(s)
- Jane Lawrence
- Department of Physiology, University of Manitoba, Winnipeg, Manitoba, Canada, R3E 3J7
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