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Abstract:
Introduction:
Spinal cord injury (SCI) results, in most cases, in permanent motor and sensory deficits, both influencing quality of life. Although anatomical MRI is of clinical value to determine the level and extent of injury, as well as remote degenerative changes, its predictive value remains limited. Magnetic resonance spectroscopy (MRS) provides the means of accessing biochemical information from the neural tissue (de Graaf, 2007). Thus holding potential for a better understanding of cellular processes associated with neurodegeneration after SCI. In the present study, we examine metabolic alterations of cellular processes in the cervical spinal cord in patients with chronic SCI.
Methods:
Spectra were measured in 16 spinal cord injury patients at 3T (Achieva, Philips Healthcare, Best, The Netherlands). Fig.1 shows the demographics of the study population, the voxel localization and a sample spectrum of the cervical spinal cord. All patients underwent a comprehensive clinical protocol including 1) the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) protocol for motor, light-touch and pin-prick score (Kirshblum, 2011) and 2) the Spinal Cord Independence Measure (SCIM) to measure daily life independence. The MRS voxel (6x9x35 mm3) was placed above the level of injury at C2/3 (Fig.1 bottom) based on a T2 weighted scan (0.4x0.4x4mm3) and using the metabolite cycling technique (Hock, 2013a and Hock, 2013b). 512 signal averages were recorded [TE=30ms, TR=2000-2500ms (heart beat triggered)] and an apodization filter after 200ms was applied before quantification with LCModel (Provencher, 1993). The neurovascular SENSE coil was used to acquire the cervical spine spectra and the total scan time was 45 minutes. All statistical analyses were performed using R Version 3.3.1 (R Core Team, 2016) and the Spearman correlation was calculated between the different metabolic ratios and clinical outcome measures.
Conclusions:
We observed associations between the metabolic level and the clinical impairment in chronic SCI above the level of injury. Moreover, we identify an activity dependent correlation between metabolic reductions of cellular process involved in neurodegeneration and clinical impairment. Further data are being collected in additional SCI and a healthy control group will be added to access trauma-induced changes. The sensitivity of cervical spinal cord MRS holds the potential for use in therapy monitoring and may serve as a biomarker in clinical trials in SCI.
