Identification of the cohort with EMD and representative imaging-based responses. (A) Identification of focal EMD among pediatric patients with r/r B-ALL treated with CD19 CAR T-cell therapy. (B-C) 18F-FDG PET/CT fusion images from UPN4 with testicular disease, with bilateral FDG-avid testicular enlargement before CAR T-cell infusion (B), which completely resolved after infusion (C). (D-G) Magnetic resonance imaging findings in UPN15 with focal CNS disease. Postcontrast axial T2 fluid-attenuated inversion recovery image (D) and 3D T1 image (E) through the level of the lateral ventricles obtained before CAR T-cell therapy demonstrated leptomeningeal enhancement along 2 of the right parietal sulci, suggesting leukemic infiltrate (D-E) (white arrows), which completely resolved after therapy on after contrast T2 fluid-attenuated inversion recovery image (F) and 3D T1 image (G) (arrows).
