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.

The rheological properties of the periodontal ligament are key parameters to understand thehomeostatic stability of the tooth supporting apparatus. The objective of this study is to lay newinsights on the rheological properties and structural information of different regions in murineperiodontal ligament by using atomic force (AFM) and multi-photon microscopy (MPM). A significantvariation in elasticity of different regions was measured. The elasticity of periodontalligament showed a significant tendency to become softer towards the furcation, the nearest areato the center of resistance of the tooth. This can open a new prospective for connecting therheological adaptation of periodontal ligament to the tooth geometry that defines the center ofresistance. Another important finding revealed by the second harmonic generation (SHG) signalexhibited by collagen fibers and measured by MPM is that the orientation of fibers in the furcationregion can both provide space for tooth vertical movement with high compressive loads andprevent horizontal tooth movement. Additionally, it was found that the dispersion of the angles atdifferent levels of cutting indicates homogeneity in the directionality of fibers across differentregions. These results provide an accurate description of the rheological properties and structuralinformation of periodontal ligament, which can serve as a base for comparison with other localand systemic diseases that may influence the periodontal ligament.

Optical Second Harmonic Generation (SHG) is obtained from adsorbed gold nanoparticles with an average diameter of 16 nm at the air / aqueous solution interface in reflection. A detailed analysis of the depth profile of the SHG intensity detected shows that two contributions appear in the overall signal, one arising from the air / aqueous solution interface that is sensitive to the gold nanoparticles surface excess and one arising from the bulk aqueous phase. The latter is an incoherent signal also known as Hyper Rayleigh scattering. The results are in agreement with an analysis involving Gaussian beam propagation optics and Langmuir isotherm. It also reveals discrepancies for the largest concentrations used and proposes a new route for the design of soft metasurfaces.