Imaging evaluation of pulmonary and abdominal complications following hematopoietic stem cell transplantation.

Hematopoietic stem cell transplantation is used to treat hematologic disorders and as an adjunct treatment for solid organ malignancies. After undergoing transplantation, patients are at risk for opportunistic infections and other complications caused by dysfunction of the immune system. Pulmonary complications include cryptogenic organizing pneumonia, opportunistic pneumonias caused by Aspergillus and Zygomycetes species and cytomegalovirus, alveolar hemorrhage, and constrictive bronchiolitis. Abdominal complications include hepatic veno-occlusive disease, graft-versus-host disease (GVHD), colitis, and hemorrhagic cystitis. Allogeneic transplant recipients are at risk for developing GVHD. Autologous and syngeneic transplant recipients are less likely to have chronic or late posttransplantation complications. Nonmyeloablative transplant recipients are less likely to develop opportunistic infections and other complications in the period immediately following transplantation, but are at risk for developing chronic GVHD and other chronic complications. Radiologic evaluation serves as the cornerstone for timely diagnosis of these complications, which is essential to reduce patient morbidity and mortality. Combining clinical factors-including the type of transplant and the point of time during the posttransplantation course-with characteristic imaging features yields the most specific and accurate differential diagnosis for radiologic findings in stem cell transplant recipients.