Ulrike Lbel1, John O. Glass1, Hiroto Inaba2, Wilburn E. Reddick1, John T. Sandlund2, Zoltn Patay1
1Radiological Sciences, St. Jude Children's Research Hospital, Memphis, TN, USA; 2Hematology-Oncology, St. Jude Children's Research Hospital, Memphis, TN, USA
Diffusion Tensor Imaging and MR spectroscopy were used to assess white matter changes in a patient who developed acute methotrexate-induced leukoencephalopathy during leukemia treatment over a period of 252 days. ADC was found to be the earliest and most sensitive indicator of MTX toxicity, while FA changes were delayed. We speculate that the initial uncoupling of ADC and FA changes may indicate a sequence of histopathological events including initial myelin injury (intramyelinic edema) and subsequent damage to the neuroaxonal units. Changes may be reversible or irreversible, but further studies are needed to determine cut-off values for ADC, FA and MR spectroscopy.