In the last couple of years there has been an explosion of 3D printed organ replicas for use during and prior to surgery. One Drexel student has done a thesis on the topic titled '3D Printed Cardiac Imaging Data' where he thoroughly examines the uses and any shortcomings. An overview of his report and findings can be found here: http://3dprint.com/9159/3d-printed-organ-replicas/ The article also includes information to better help you understand how the scanning and printing process works. The student's video can be found below as well:
http://vimeo.com/98961653