The researchers used diffusion tensor imaging (DTI) to assess the tissue integrity of major cervical cord tracts (posterior columns (PCs) and lateral corticospinal tracts (CSTs)) to see if there was a relationship with specific clinical function carried by those tracts.
The study included 37 people with MS or NMO with prior transverse myelitis. Clinical assessments used included finger vibratory thresholds, 25-foot timed walk test (25FTW), 9-hole peg test (9HPT) and expanded disability status scale (EDSS). DTI covered C1 through to C6.
Results from the DTI analyses of discrete spinal cord tracts were shown to correlate with specific clinical functions carried by those tracts. Reduced vibratory sense was specifically related to abnormal radial diffusivity (RD) and fractional anisotrophy (FA) within the PCs, while DTI parameters within the CSTs had no apparent relation to vibration sense.
The more integrative neurological functions tested by 9HPT, 25FTW and EDSS each showed a consistent relationship to RD and FA within both the PCs and CSTs. For the 9HPT and 25FTW, combined PC and CST injury was more frequent in people with more disability compared with when only one tract is affected.
Authors: Naismith RT, Xu J
Source: Neurology. 2013 May 10. [Epub ahead of print]
Read the abstract