3D printed models of congenital heart disease: How accurate and how useful are they? Ivan Lau, 1 Andrew Squelch, 2,3 and Zhonghua Sun 1 1. Discipline of Medical Radiation Sciences, School of Molecular and Life Sciences, Curtin University, Perth, Western Australia, Australia 2. Discipline of Exploration Geophysics, Western Australian School of Mines, Minerals: Energy and Chemical Engineering, Curtin University, Perth, Western Australia, Australia 3. Computational Image Analysis Group, Curtin Institute for Computation, Curtin University, Perth, Western Australia, Australia 312 [AMJ 2019;12(11):312-314] Editorial Please cite this paper as: Lau I, Squelch A and Sun Z. 3D printed models of congenital heart disease: How accurate and how useful are they? AMJ 2019;12(11):312–314. https://doi.org/10.35841/1836-1935.12.11.312-314 Corresponding Author: Prof Zhonghua Sun Discipline of Medical Radiation Sciences, School of Molecular and Life Sciences, Curtin University, Perth, WA, 6845, Australia Email: z.sun@curtin.edu.au ABSTRACT Three-dimensional (3D) printing in the domain of congenital heart disease (CHD) is still in its infancy. The aim of this editorial is to highlight the key findings of a recently published systematic review and meta-analysis on the accuracy and clinical value of 3D printed heart models (3DPHM). The analysis found that 3DPHM can be generated with high accuracy and the most reported application of 3DPHM is to facilitate pre-operative planning. Key Words 3D printing, additive manufacturing, stereolithography, 3D model, congenital heart disease, congenital heart defect Introduction Three-dimensional (3D) printing has been widely utilized in different specialties within the medical field for decades. 1-3 However, in the domain of cardiovascular specialties, this technology is still considered fairly new. 4 The conventional way to interpret the medical images from two- dimensional (2D) flat screen lacks comprehensiveness, hence tangible 3D printed heart models (3DPHM) were created to improve the users’ perception on the depth information of the cardiac anatomies. 3-6 Although there are increasing reports on the use of 3DPHM, most of them remain anecdotal, and very few of them perform quantitative measurements of the accuracy and clinical value of the 3DPHM. 4,7 The relevant questions are: if the 3DPHM are accurate, to what extent are they accurate; if the 3DPHM are useful, in what areas are they useful; and do all the studies share the same findings? This editorial aims to provide a succinct summary of a recently published systematic review and meta-analysis on the accuracy and clinical value of 3DPHM. 4 How accurate and useful are the 3D printed heart models? A total of 24 articles were included in the systematic review and 7 of them were used in the meta-analysis. 4 Based on the findings of this review, there are 4 different imaging modalities that can be used to generate 3DPHM, with computed tomography angiography (CTA) being the dominant, followed by cardiac magnetic resonance (CMR), echocardiography, and rotational angiography. Materialise Mimics is the most popular software for cardiac image segmentation, with 12 out of 24 studies (50 per cent) reporting its application. 4 It was found that the accuracy of the 3DPHM is reported in relatively few studies since only 7 out of 24 provided the statistical measurements of the 3DPHM. Nevertheless, all of these studies shared the same findings: 3DPHM is highly accurate. Based on the meta-analysis of 3 eligible studies, the pooled mean deviation of 3DPHM measurement and original medical images measurement is 0.04mm, 95 per cent CI (-0.16, 0.23) (Figure 1), which is