Additive Manufacturing of a Compliant Multimaterial Heart Model

Additive manufacturing technologies are increasingly taking place in the medical field, enabling the creation of graspable patient-specific anatomical models. Because of their potentiality in improving the understanding of complex anatomies and their shown effectiveness for residents' training, devices testing and planning of innovative surgical interventions, 3D printed models have been incorporated also into cardiac surgery and interventional cardiology. To offer valid and reliable support, however, these printed models are often required to be flexible, with an adequate mechanical response, especially when they aim at replicating soft tissues. The goal of this paper is to provide a high-quality and robust template of a patient-specific whole heart model, obtained starting from a Computed Tomography dataset and exploiting a material jetting printer. Due to the significant shape complexity and the variability in compliance featuring the human heart, the selection of the materials have been diversified, taking into account different model wall thicknesses. Thanks to the capability of the material jetting technology, the 3D model of the heart has been printed with two different material assignments, designed to get highly realistic feedback and reduce the gap between the real heart and the printed ones. Eventually, an accuracy evaluation of the printed model has been performed, by means of a laser 3D scanner. Some further considerations about time and costs required to produce the model are part of the paper, together with a discussion about potential areas of improvement, from materials characterization to the need of speeding up and automating the segmentation procedure.