Spinal Cord MRI

  • Posted on: Wed, 08/26/2015 - 15:49
  • By: OCHIS Chief Editor
Abstract: 
Recently for the first time we have discovered biologically plausible and spatially distinct resting state networks (RSNs) exist in the human spinal cord.  

fMRI: sensory and pain

The spinal cord is the first part of the central nervous system (CNS) involved in the transmission of somatosensory information from the body periphery to the brain, as well as the last part of the CNS involved in relaying motor signals to the body periphery.

Non-invasive functional MRI (fMRI) offers the possibility of studying spinal cord function and role in sensory, motor and pain processes. However functional MRI of the spinal cord is very challenging due to its small cross-sectional area (∼1cm2, necessitating the use of small voxel sizes, which leads to a low signal-to-noise ratio), magnetic susceptibility differences in tissues adjacent to the cord, e.g., vertebral bodies and spinous processes (causing signal loss and image distortion), as well as the influence of physiological noise (obscuring neuronally induced signal changes).

Optimised protocols to acquire and analyse spinal cord fMRI has been developed in Functional MRI of the Brain (FMRIB) of Oxford, such as fewer phase encoding steps with parallel imaging [1]; physiological noise correction [2][3]; and slice-wise motion correction, robust group co-registration [1].

Recently for the first time we have discovered biologically plausible and spatially distinct resting state networks (RSNs) exist in the human spinal cord [4]. Analysis of spinal RSNs could become an important tool in investigating clinical populations that involve spinal cord pathology, such as multiple sclerosis (MS) and spinal cord injury (SCI) as well as the neuroplastic and sensitisation changes known to occur in the spinal cord in various forms of chronic pain.

Neurodegeneration diseases

MS has benefited mostly from advanced quantitative spinal cord imaging techniques. Conventional MRI (T1/T2) has proven to be sensitive for detecting lesions, however non-conventional MRI (fMRI, DTI, magnetization transfer ratio (MTR), myelin imaging and MR spectroscopy (MRS)) can provide important insight into the pathobiology of neurodegeneration, demyelination and axonal loss.

Long spinal cord lesions and chronic pain symptoms are often found with neuromyelitis optica (NMO), a disease similar to MS. Recently we have studied NMO using brainstem and spinal cord MRI, and found that spinal cord atrophy is linked to patients’ disability while glutamate in brainstem is significantly associated with patients’ degree of neuropathic pain. This exciting result confirms that brainstem plays important role in the descending pain inhibition despite lesion damage in spinal cord.

Together with physics difficulties for the quantitative spinal cord imaging, there are also many challenges in the development of imaging analysis, such as automatic cord segmentation, volumetric atrophy assessment and cross-modality group registration.

References

[1] Brooks JC, Kong Y, Lee MC, Warnaby CE, Wanigasekera V, Jekinson M, Tracey I. Stimulus site and modality dependence of functional activity within the human spinal cord. J Neurosci 2012 May 2;32(18):6231-9.

[2] Brooks JC, Beckmann CF, Miller KL, Wise RG, Porro CA, Tracey I, Jenkinson M. Physiological noise modelling for spinal functional magnetic resonance imaging studies. Neuroimage 2008 Jan 15;39(2):680-92

[3] Kong Y, Jenkinson M, Andersson J, Tracey I, Brooks JC.Assessment of physiological noise modelling methods for functional imaging of the spinal cord. Neuroimage 2012 Apr 2;60(2):1538-49

[4] Kong Y, Eippert F, Beckmann CF, Andersson J, Finsterbusch J, Büchel C, Tracey I, Brooks JC. Intrinsically organized resting state networks in the human spinal cord. PNAS 2014 Dec 16;111(50):18067-72.

Author's Biography

Yazhuo Kong

Dr. Yazhuo Kong obtained his B.Eng from the University of Science and Technology of China and Ph.D in neuroimaging from the University of Sheffield, UK. Currently he is working as a research fellow in the FMRIB centre of the University of Oxford. Dr. Kong also holds an honorary non-clinical fellow position in the clinical neurology of Oxford John Radcliffe Hospital. His research focuses on quantitative MRI (structural, diffusion, spectroscopy and fMRI) of human spinal cord with applications to pain and neurodegeneration diseases. He has published several papers in top neuroscience journals such as JCBFM, NeuroImage and PNAS.

Email: ykong@fmrib.ox.ac.uk