3D Printing of a Cirrhotic Liver with Parenchymal Translucency and Highlighted Portal and Hepatic Veins for Pre-Tips Planning

Reliance on 2D imaging to perform TIPS renders it a “semi-blind” procedure, with a potential for complications, such as extracapsular hemorrhage and non-target puncture. Availability of custom 3D modeling displaying hepatic (HVs) and portal veins (PVs) can facilitate planning and operator training by revealing the ideal path for potential tract creation. We describe our technique for creating a custom 3D liver model for use in TIPS planning. A thin-slice triple phase contrast-enhanced abdominal CT was obtained for TIPS planning. DICOM data was then transferred to Seg3D (v2.4.0), where a median filter and crop were applied to smooth and isolate the liver. Segmentation was performed in 3DSlicer (v4.5). For HV and PV segmentation, fiducial seeds were placed and a semi-automated simple region growing algorithm was applied, followed by marching cubes to generate a mesh. For liver segmentation, slices were contoured, followed by a robust statistics segmenter and mesh generation by marching cubes. The final model for 3D printing was generated by performing a boolean subtraction of vasculature, and exported as a stereolithography (.STL) file. The model was then printed on a ProJet 3500 HD Max in VisiJet Crystal, a translucent acrylate polymer. To better visualize HVs and PVs, the interior walls were painted in vibrant colors. The resultant liver model features parenchyma formed with translucent acrylate polymer, enabling visualization of the separately colored HVs and PVs. The HVs and PVs are hollow, allowing evaluation of the geometric relationships between venous systems and “dry run” catheter interrogation. Selection of a post-printing method for coloring the HVs and PVs was important as it greatly reduces the complexity and expense of the 3D print itself, when compared to a multi-color, multi-material approach. As 3D printers become ubiquitous tools of modern medical care, routine 3D printing for TIPS planning is feasible. Using on-site segmentation, a physically transparent liver model may be produced containing hollowed, color coded HVs and PVs to facilitate TIPS planning and potentially decrease morbidity.