Purpose or Case Report: PET/MR is a valuable and growing imaging method for the assessment and management of pediatric bone tumors. Although plain radiography remains the first line modality for initial evaluation, cross sectional imaging is often required for further characterization of indeterminate or aggressive appearing lesions. Due to its superior soft tissue contrast resolution compared to CT, MR has become the mainstay in tissue characterization, locoregional staging, and surgical planning of pediatric bone tumors. By adding functional and metabolic information, FDG-PET imaging is useful for “one stop” local tumor and whole-body staging, evaluating response to therapy and surveillance. 18F-FDG PET/MR scans have the benefit of lower radiation and increased patient convenience compared to 18F-FDG PET/CT scans. However, due to the relatively recent development of this technology, many radiologists may be unfamiliar with the technical considerations and interpretation pearls and pitfalls of PET/MR. This educational exhibit reviews the imaging technique, reporting requirements, and imaging characteristics of the most common pediatric bone tumors with 18F-FDG PET/MR.
Methods & Materials: We conducted a comprehensive literature search on 18F-FDG PET/MR of pediatric bone tumors and have included the most current evidence-based information for review. We also present our institutional approach and experience with performing 18F-FDG PET/MR scans of pediatric bone tumors.
Results: We describe the imaging technique and reporting criteria for conducting 18F-FDG PET/MR scans of bone tumors in children and young adults. We review the epidemiology, pathology, 18F-FDG PET/MR imaging characteristics, and treatment monitoring approaches for the most common pediatric bone tumors, including osteosarcoma, Ewing sarcoma, primary bone lymphoma, bone and bone marrow metastases, and Langerhans cell histiocytosis. We also discuss various potential “false positive” bone lesions, and some important similarities and differences between 18F-FDG PET/MR and 18F-FDG PET/CT. Finally, we provide insight into the future directions and developments of this new technology.
Conclusions: Familiarity with 18F-FDG PET/MR in the evaluation of pediatric bone tumors is of growing importance. This review covers the 18F-FDG PET/MR imaging features of the most common pediatric bone tumors, as well as technical considerations, reporting methods, and future possibilities for performing “one stop” 18F-FDG PET/MR cancer staging of children and young adults.