Volume 12 Supplement 1
Patterns of spinal cord atrophy in HTLV-1 associated myelopathy/ tropical spastic paraparesis (HAM/TSP)
© Charlip et al. 2015
Published: 28 August 2015
Spinal cord inflammation and atrophy contribute to debilitating symptoms in HAM/TSP. We have developed a robust and fast algorithm to determine average cross-sectional area in cervical (c-spine) and thoracic (t-spine) spinal cords by tracing contours perpendicular to the edge in T1-weighted MRI images. The cross-sectional areas in the c- and t-spines were determined in 25 HAM/TSP, 10 asymptomatic carriers (AC) and 10 healthy volunteer (HV) subjects. To date, we have followed 8 of the HAM/TSP patients longitudinally over a two-year period. When compared to the HV data, the HAM/TSP spinal cord profiles fell into four general categories: atrophic entire spine (48%), atrophic t-spine (32%), atrophic c-spine (8%), and normal (12%). The majority of ACs had similar spinal cord profiles to those in the HV group, however, 3 ACs showed a pattern similar to HAM/TSP. As a group, both HAM/TSP c- and t-spines were significantly lower than those of HV (p<0.01). In the 8 patients with follow-up scans, spinal cord size showed an overall decreasing trend over time. In a rapidly progressing patient with the shortest disease duration, we could estimate spinal cord atrophy at a rate of 11% a year in the thoracic cord. In addition, change in proviral load negatively correlated with change in both c- and t-spine cross-sectional area (p<0.05) for patients with shorter disease duration and increasing proviral loads (i.e. an increase in proviral load was associated with a more atrophic cord). These results suggest that the pattern of spinal cord tissue damage is specific to the underlying inflammatory disease, a finding that has direct implications for the use of average cross-sectional spinal cord area as a surrogate end point for clinical trials.
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.