CT-based non-destructive quantification of 3D-printed hydrogel implants

Additive manufacturing of hydrogel-based implants, as e.g for the human skull are becoming more important as they should allow a modelling of the different natural layers of the skullcap, and support the bone healing process. Nevertheless, the quality, structure and consistency of such 3D-printed hydrogel implants are important for the reliable production, quality assurance and further tests of the implant production. One possibility for non-destructive imaging and quantification of such additive manufactured hydrogels is computed tomography combined with quantitative image analysis. Hence, the goal of this work is the quantitative analysis of the hydrogel-air relationship as well as the automated computation of the hydrogel angles between the different hydrogel layers. This is done by application and evaluation of various classical image analysis methods such as thresholdig, morphological operators, region growing and Fourier transformation of the CT-slices. Results show, that the examined quantities (channels in the hydrogel lattice, angles between the layers) are in the expected ranges, and it can be concluded that the additive manufacturing process may yield usable hydrogel meshes for reconstructive medicine.