The two asymptomatic carriers in this group showed thoracic cord volumes of 15,548 mm3 and 15,362 mm3, well within the range of HVs, whereas the two possible HAM/TSP subjects demonstrated lower thoracic cord volumes of 12,308 mm3 and 7,933 mm3 that were close to or within the cord volume range of definite HAM/TSP subjects. These results suggest that the 3D volumetric measurements of the spinal cord may be a highly informative indicator of CNS involvement associated

with HTLV-I infection. To examine whether Smoothened Agonist chemical structure the spinal cord volumes correlate with measures of disability, the relationship between spinal cord 3D volumetric measurements and clinical parameters such as disease duration, EDSS, and IPEC were analyzed. The correlation between cervical cord volume and disease duration in definite HAM/TSP was significant at the P < .05 level (R2 = .77, P = .049; Pearson correlation), but was not statistically significant following correction for multiple comparisons. Otherwise no significant correlations were observed between spinal cord volumes and age, EDSS, or IPEC in this retrospective cross-sectional study. We have used a semiautomated technique for quantification of spinal cord volume from 3D MR images. Applied to subjects with HAM/TSP, an inflammatory myelopathy with a well-characterized progressive

clinical course resembling primary progressive multiple sclerosis, we showed that spinal cord atrophy distinguishes subjects with HAM/TSP from HVs. Thoracic cord volumes were over one third lower, and Lapatinib mw cervical cord volumes were substantially reduced in subjects with HAM/TSP, demonstrating, for the first time by MRI, substantial volume loss in the HAM/TSP cervical cord. In individuals with HTLV-I infection but not fulfilling ascertainment from criteria for definite HAM/TSP, the current technique appears to be informative with respect to distinguishing those who are asymptomatic from those who

demonstrate abnormalities on clinical examination. Thus the 3D MRI spinal cord volume quantification employed in this study is a sensitive tool for detecting spinal cord volume loss, and may be a sensitive indicator of CNS involvement in HTLV-I infection. Previous studies to characterize spinal cord volume by MRI in HAM/TSP have relied on measurement of midthoracic cross-sectional area ratios as a surrogate for cord volume and have not shown a clear relationship between atrophy and disease progression.2008 Although the 3D MRI quantification of spinal cord volume employed in this study captures the full extent of spinal cord involvement, spinal cord volumes did not correlate with measures of clinical disability such as EDSS and IPEC in this cross-sectional study of subjects with HAM/TSP. A positive correlation between cervical spine volume and disease duration was seen at the P < .