PROGRESSIVE MULTIFOCAL LEUKOENCEPHALOPATH Y STUDIED BY MAGNETIZATION-TRANSFER IMAGING

Purpose: magnetization transfer imaging (MT) has been used to study th e degree of demyelination in progressive multifocal leukoencephalopath y (PML). Material and method: two groups were studied : a group of 10 HIV + patients with clinical, MR features, biological and/or biopsy pr oven PML, and a group of 11 normal volunteers with matched age. MT rat io (MTR) were obtained from the center of the PML lesions and 11 areas of normal appearing white matter (NAWM) in the control group. Results : the mean MTR of NAWM in the control group was 46.6% (SD = 2,3). PML lesions demonstrated a strong and significant (p = 0) decreased of the MTR with mean MTR value of 22.4% (SD = 2,3). Conclusion: MT character ized the demyelinating process in PML, and can be used to improve diag nosis. Furthermore, MT allowed a quantification of the degree of demye lination which can be helpful in other demyelinating process of CNS su ch as multiple sclerosis.