PET/CT imaging of the late-gestation fetal brain in pregnant rats: A proof-of-concept study.

Preclinical PET studies offer the opportunity to elucidate molecular mechanisms underlying early neurodevelopment with minimal invasiveness. We demonstrated the feasibility of fetal brain PET in four pregnant rats ( = 42 fetuses). [F]FDG uptake in rat fetuses was readily visualized by PET imaging. Additionally, in vivo fetal brain [F]FDG concentration (standardized uptake value (SUV)) was significantly correlated with ex vivo SUV from matched post-mortem brains ( = 0.90,  < 0.001). We further investigated the effect of the dopamine receptor antagonist haloperidol on cerebral glucose metabolism (CMR) and [C]raclopride binding in maternal and fetal brains. Dopamine D2 receptor blockade by haloperidol resulted in significant decreases ( < 0.001,  = 33 vs 9 fetuses) in in vivo CMR and ex vivo [F]FDG SUV. Consistently, haloperidol pretreatment significantly decreased [C]raclopride SUV ratio (SUVR) by 17% ( < 0.001,  = 6 vs 6 fetuses) in the fetal whole-brain, using the maternal cerebellum as the reference region. In all, our results show that PET/CT imaging of the fetal rat brain can reliably quantify specific molecular targets in vivo, and future translational studies of neurodevelopment are feasible in this model.