Hyperperfusion on magnetic resonance imaging in acute chemotherapy-related leukoencephalopathy

Acute chemotherapy-related leukoencephalopathy can present similar to acute stroke with symptoms including aphasia, dysarthria, and hemiplegia. Differentiation based on clinical appearance is challenging, and physicians must distinguish between the 2 conditions rapidly to institute appropriate therapies. An 8-year-old male with acute lymphoblastic leukemia receiving chemotherapy, including intrathecal methotrexate, presented to our emergency center with 2 hours of expressive aphasia and flaccid right hemiplegia. Emergent magnetic resonance imaging (MRI) was obtained, demonstrating diffusion restriction within bilateral corona radiata and centrum semiovale. Magnetic resonance perfusion revealed mildly increased perfusion, a finding inconsistent with ischemic stroke and previously unreported in acute chemotherapy-related leukoencephalopathy without necrosis. This increased perfusion conclusively eliminated stroke from the clinical differential. Magnetic resonance perfusion imaging proved valuable to rapidly distinguish acute chemotherapy-related leukoencephalopathy from ischemia, and the evaluation of perfusion alterations in this disorder may provide further insight into the pathophysiology of this entity.