Abstract
The diagnosis of patients with fever of unknown origin (FUO) in pediatric heart transplantation is a challenging medical problem. The physician should differentiate between rejections, infections, malignancy, adrenal insufficiency, and drug fever. Immunosuppressive therapy in these patients exposes them to a high risk of developing a post-transplantation fungal infection. In this case, we discuss the diagnostic contribution of the (99m)Tc-UBI scan and (18)F-FDG PET scan for diagnosis of fungal infection causing FUO in these patients.