CNS radiographic abnormalities in TA-TMA. An 18-year-old man (patient 1 in Table 1) experienced progressive neurologic decline after HCT and underwent magnetic resonance imaging (A-G) on day 124 after HCT. He was diagnosed with TA-TMA on day 39. (A-B) Axial fluid-attenuated inversion recovery (FLAIR) images demonstrate multifocal areas of signal abnormality (black arrows) in the cerebellum, brainstem, periventricular white matter, and posterior limb of the left internal capsule and adjacent basal ganglia. (C) A T2-trace diffusion–weighted image demonstrates corresponding diffusion restriction predominantly within areas of signal in the cerebellum (white arrows). (D-E) Progressive hyperintense signal abnormality on FLAIR throughout the cerebellum, brainstem, cerebral white matter, and deep gray nuclei (white arrowheads). (F-G) Diffusion-weighted imaging demonstrates corresponding progressive diffusion restriction (black arrowheads). A 4-year-old patient with neuroblastoma (patient 3 in Table 1) experienced altered mental status on day 10 after autologous HCT and underwent a head CT (H-I). TA-TMA was diagnosed on the same day. Axial computed tomographic images demonstrate a new, ovoid, high-attenuation hemorrhage in the genu of the corpus callosum (arrowhead), as well as a more subtle hemorrhage along the cortical surface of the posterior right frontal lobe (arrow).