Micro‐CT and high‐field MRI for studying very early post‐mortem human fetal anatomy at 8 weeks of gestation.

Objective: This study involved very early post‐mortem (PM) examination of human fetal anatomy at 8 weeks of gestation (WG) using whole‐body multimodal micro‐imaging: micro‐CT and high‐field MRI (HF‐MRI). We discuss the potential place of this imaging in early first‐trimester virtual autopsy. Methods: We performed micro‐CT after different contrast‐bath protocols including diffusible iodine‐based contrast‐enhanced (dice) and HF‐MRI with a 9.4 T machine with qualitative and quantitative evaluation and obtained histological sections. Results: Nine fetuses were included: the crown–rump length was 10–24 mm and corresponded to 7 and 9 WG according to the Robinson formula. The Carnegie stages were 17–21. Dice micro‐CT and HF‐MRI presented high signal to noise ratio, >5, according to the Rose criterion, and for allowed anatomical phenotyping in these specimens. Imaging did not alter the histology, allowing immunostaining and pathological examination. Conclusion: PM non‐destructive whole‐body multimodal micro‐imaging: dice micro‐CT and HF‐MRI allows for PM human fetal anatomy study as early as 8 WG. It paves the way to virtual autopsy in the very early first trimester. Obtaining a precision phenotype, even regarding miscarriage products, allows a reverse phenotyping to select variants of interest in genome‐wide analysis, offering potential genetic counseling for bereaved parents. Key points: What's already known about this topic? Autopsies considered too invasive are often refused by grieving couples after fetal loss.Fetal virtual autopsy has developed with standard imaging (MRI and CT) used after 24 weeks of gestation (WG) and micro‐CT and high‐field MRI (HF‐MRI) used from 11 to 24 WG.The current scientific literature on micro‐CT and HF‐MRI before 11 WG is weak.Miscarriages are common and require further explorations and research. What does this study add? Iodine‐contrast micro‐CT and HF‐MRI allow for post‐mortem human fetal anatomy visualization as early as 8 WG and pave the way for virtual autopsy at very early first trimester and thus precise phenotyping of miscarriage products.The choice of either technique will be based on cost, availability, ease of use, target organ of interest, preparation and acquisition duration.Micro‐imaging does not appear to exclude subsequent histological examination. [ABSTRACT FROM AUTHOR]