[(18)F]FDG PET/MRI enables early chemotherapy response prediction in pancreatic ductal adenocarcinoma

PURPOSE: In this prospective exploratory study, we evaluated the feasibility of [(18)F]fluorodeoxyglucose ([(18)F]FDG) PET/MRI-based chemotherapy response prediction in pancreatic ductal adenocarcinoma at two weeks upon therapy onset. MATERIAL AND METHODS: In a mixed cohort, seventeen patients treated with chemotherapy in neoadjuvant or palliative intent were enrolled. All patients were imaged by [(18)F]FDG PET/MRI before and two weeks after onset of chemotherapy. Response per RECIST1.1 was then assessed at 3 months [(18)F]FDG PET/MRI-derived parameters (MTV(50%), TLG(50%), MTV(2.5), TLG(2.5), SUV(max), SUV(peak), ADC(max), ADC(mean) and ADC(min)) were assessed, using multiple t-test, Man–Whitney-U test and Fisher’s exact test for binary features. RESULTS: At 72 ± 43 days, twelve patients were classified as responders and five patients as non-responders. An increase in ∆MTV(50%) and ∆ADC (≥ 20% and 15%, respectively) and a decrease in ∆TLG(50%) (≤ 20%) at 2 weeks after chemotherapy onset enabled prediction of responders and non-responders, respectively. Parameter combinations (∆TLG(50%) and ∆ADC(max) or ∆MTV(50%) and ∆ADC(max)) further improved discrimination. CONCLUSION: Multiparametric [(18)F]FDG PET/MRI-derived parameters, in particular indicators of a change in tumor glycolysis and cellularity, may enable very early chemotherapy response prediction. Further prospective studies in larger patient cohorts are recommended to their clinical impact. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13550-021-00808-4.