Diffusion-weighted imaging characteristics of methotrexate-induced acute encephalopathy

Abstract

Methotrexate (MTX)-induced encephalopathy is a grave complication in patients with malignancies. The early diagnosis of acute encephalopathy was difficult by conventional computed tomography (CT), and T1- or T2-weighted magnet resonance (MR) imaging. We report that the diffusion-weighted (DW) imaging is useful for early detection of acute leukoencephalopathy.

Keywords: Diffusion‐weighted imaging; encephalopathy; magnetic resonance imaging; methotrexate; neurotoxicity.

Figure 1

(A) Post‐R‐MPV therapy (3 courses) on day 12, T2‐weighted, fluid‐attenuated inversion recovery (FLAIR), and diffusion‐weighted (DW) images at 48 hours after the onset of neurological symptoms. T2‐weighted and FLAIR images show no apparent expansion of abnormal signals while the DW image shows mildly increased signals in the right periventricular area and the corona radiata (arrows). (B) T2‐weighted and FLAIR images on day 22 show mild hyperintensity in the bilateral periventricular white matter while the DW image shows improvement of the abnormal signal.