18F-FDG PET/MRI for therapy response assessment in sarcoma: comparison of PET and MR imaging results

Background18F-Fluorodeoxyglucose (FDG) positron emission tomography (PET) has proven to be of substantial benefit in imaging of sarcoma patients. We therefore investigated the feasibility and benefit of combined PET/magnetic resonance imaging (MRI).MethodsTwelve patients with sarcoma who underwent FDG PET/MRI for staging and response assessment after chemotherapy were included.ResultsBased on contrast-enhanced MRI and application of Choi criteria, therapy response was classified as stable disease in 6/12 patients (50%) and as partial remission in 6/12 patients (50%).ConclusionIn sarcoma patients, response assessment using Choi criteria based on contrast-enhanced MRI in comparison to FDG PET imaging only demonstrates slight correlation.