LAUSR

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.