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

Abstract

Background: Methotrexate 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. Methods: Seventeen 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. Results: In 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. Conclusion: Methotrexate 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.

Keywords

• Methotrexate
• Neurotoxicity
• Diffusion weighted MRI