FDG-PET-MRI of a 70-year-old patient with acute intestinal GVHD. (A) Maximum intensity projection of PET and (C) the fused PET-MRI show increased FDG uptake in small and large bowel. (B) Coronary T1-weighted postcontrast MRI allows for assessment of corresponding morphological changes, including mural hyperenhancement, wall thickening, mural stratification, and the Comb sign.