3D printed ventricular septal defect patch: a primer for the 2015 Radiological Society of North America (RSNA) hands-on course in 3D printing

Abstract

Hand-held three dimensional models of the human anatomy and pathology, tailored-made protheses, and custom-designed implants can be derived from imaging modalities, most commonly Computed Tomography (CT). However, standard DICOM format images cannot be 3D printed; instead, additional image post-processing is required to transform the anatomy of interest into Standard Tessellation Language (STL) format is needed. This conversion, and the subsequent 3D printing of the STL file, requires a series of steps. Initial post-processing involves the segmentation-demarcation of the desired for 3D printing parts and creating of an initial STL file. Then, Computer Aided Design (CAD) software is used, particularly for wrapping, smoothing and trimming. Devices and implants that can also be 3D printed, can be designed using this software environment. The purpose of this article is to provide a tutorial on 3D Printing with the test case of complex congenital heart disease (CHD). While the infant was born with double outlet right ventricle (DORV), this hands-on guide to be featured at the 2015 annual meeting of the Radiological Society of North America Hands-on Course in 3D Printing focused on the additional finding of a ventricular septal defect (VSD). The process of segmenting the heart chambers and the great vessels will be followed by optimization of the model using CAD software. A virtual patch that accurately matches the patient’s VSD will be designed and both models will be prepared for 3D printing.

Hands-on surgical training of congenital heart surgery using 3-dimensional print models

“…For the procedures that require a complex form of surgical patch, the required patch can be graphically designed and printed preoperatively. 23 The 3D print patch model can be used as the template for trimming the surgical patch to be sewn on the patient's heart either before or during the surgery. Furthermore, newly developed surgical procedures can be tested on 3D print models before actual trial on patients.…”

A G-Code Generator for Volumetric Models

“…In the papers of [13,14], those areas that have benefited from LM are presented, including surgical planning, tissue replacement, pathologic assessment, education, and medical research. In [15], a practical LM procedure had been presented to create a heart model and a fixation patch, which were used in a remedy operation in an infant's heart. In the procedure, the researchers used a segmentation software to extract the blood pools of the heart and major vessels from the input computerized tomography (CT) scan data.…”

“…In the research presented in [6,7,[13][14][15][16][17], the scanned objects are contained in volume data sets. Before the LM processes starts, they have to be converted into polygonal representations to match the input data format of the slicers.…”

“…In the paper of [18], Oropallo and Piegl regarded G-code generation for voxel-based models as one of the top challenges in LM. The work of [6,7,[13][14][15][16][17] and the proposition of [18] inspired us to develop a G-code generator, aiming at translating voxel-based models into G-code programs to enhance the usefulness of LM in medical and other industrial applications.…”

Cardiothoracic Applications of 3-dimensional Printing

“…They are relatively simple to print from contrast-enhanced CT, MRI and more recently, echocardiography [3, 17, 40, 41, 45–47]. Kim et al reported the utility of 3D printed models for occluder device sizing and selection of the approach to cross the defect in cases of a muscular VSD and a fenestrated ASD with a large atrial septal aneurysm [48].…”