In Vivo and Ex Vivo CT Imaging of Zebrafish Gonads

3D imaging of the gonads in adult zebrafish in vivo is of great interest, as it allows to follow up on their development and/or the egg development in the same individual over time. Optical-based imaging methods can hardly be applied on the adult zebrafish, due to their limited transparency. In this chapter, we will demonstrate the application of micro computer tomography (CT) imaging for in vivo 3D imaging of the gonads in adult zebrafish. We explain how the limited soft-tissue contrast in CT can be overcome and which X-ray dose levels can be expected using this technique. Moreover, we will use high-resolution microCT to perform ex vivo 3D virtual histology of the adult zebrafish, which allows a simple quantitative analysis of the gonad regions, malformation or alterations in the development of the follicles.