Child with acute methotrexate related neurotoxicity: Can diffusion weighted MRI help??

BackgroundMethotrexate is widely used chemotherapy especially in pediatric hematological malignancy. It may associate with acute neurotoxicity. We evaluate the role of the diffusion-weighted imaging (DWI) in the early detection of the acute methotrexate neurotoxicity.MethodsSeventeen pediatric patients receiving high-dose methotrexate with clinical manifestation of neurotoxicity (seizures, headache, aphasia, hemiparesis or altered mental status) were included in our study. MRI was obtained in all cases within 48 h of onset of symptoms. DWI was done as a part of the routine MRI study.ResultsIn all patients, initial MRI showed abnormal restricted diffusion in the centrum semiovale. FLAIR is positive in 9 cases showing bright signal. All patients had follow-up MR (within two weeks); in all cases there was resolution of the diffusion abnormality and interval development of abnormal signal intensity on FLAIR and T2WI.ConclusionMethotrexate can result in reversible neurotoxicity in the form of white matter injury. DWI may be used in early detection of such changes; therefore, it provides a rapid, noninvasive readily available tool by which neurotoxicity can be early detected and treated. It has the potential to alert the oncologist to this event and provide a technique by which neurotoxicity can be monitored.