Relationship between changes in spinal cord and brain morphometry to clinical recovery following acute spinal cord injury

Aim 1
Establishing the time course of morphometric changes (i.e. atrophy) at spinal and cortical level following acute SCI (Longitudinal investigation).

Aim 2
Assessment of the relationship and predictive value between early structural changes and long term clinical outcome (Longitudinal investigation).

Methods
In order to measure anatomical changes over time within the spinal cord we will measure the cross-sectional cord area at cervical level (Freund et al., 2011) (Figure 1). To assess degenerative changes in cortical and subcortical regions over time we will apply voxel- and tensor based morphometry (VBM, TBM) (Ashburner et al., 2003), voxel based cortical thickness (VBCT) and voxel-based quantification (VBQ) of magnetization transfer (MT), longitudinal relaxation rate (R1=1/T1) and R2* relaxation parameters (Draganski et al., 2011) in the framework of statistical parametric mapping (SPM) (http://www.fil.ion.ucl.ac.uk/spm) at four different time points within the first year post injury. These are unbiased automated methods based on a voxel-wise analysis, that can detect differences in grey and white matter volume, cortical thickness, myelin content and iron depositions in deep grey matter (putamen, pallidum, pulvinar and substantia nigra), respectively (Hutton et al., 2009a; Weiskopf et al., 2011). In order to measure functional cortical reorganization, we will carry out a cross-sectional functional brain imaging study (Friston et al., 1995a; Friston et al., 1995b) using upper and lower limb paradigms such as hand grip, median and tibial nerve stimulation and thermal stimulation of dermatomes. Regression analyses will then explore relationships between the cited imaging parameter to disability.

(A) T1 weighted brain and cervical spinal cord scan showing the region of cord cross sectional area measurement (within white horizontal bars).
(B & C) Cord area in a control and SCI subject, respectively.
(D) Box and Whisker plot showing the reduced cord area in SCI patients when compared to controls (Freund et al., 2011).