Abnormal spinal MRI findings in human T-cell lymphotrophic virus type I-associated myelopathy.

We describe three cases of HTLV-I-associated myelopathy (HAM) with abnormal spinal magnetic resonance imaging (MRI) findings. The serum and cerebrospinal fluid (CSF) of all 3 patients tested positive for anti-HTLV-I antibody. Swelling of the spinal cord with high-intensity lesions on T2-weighted images was observed. Corticosteroid treatment in the case of two patients gradually improved the symptoms, decreased the protein and IgG levels as well as the cell count, and reduced the abnormal MRI findings. To confirm the assumption that abnormal spinal MRI findings are reflective of active inflammation, we compared the clinical parameters, namely, the protein content, IgG level, and cell count, in the CSF of patients exhibiting abnormal spinal MRI findings with those in the case of patients without spinal MRI lesions. The protein contents, IgG levels, and number of cells in the CSF of patients with MRI lesions were significantly higher than those in the CSF of patients without lesions. These findings support the fact that abnormal MRI findings in the spinal cord may be reflective of active inflammation in the early stages of rapidly progressive HAM.