Copyright © 2007 by ASME 1 INTRODUCTION Abdominal aortic aneurysm (AAA) is a local, permanent, irreversible dilation of the infrarenal section of the aorta that risks rupture until treated. AAA is defined as an infrarenal diameter 1.5 times the normal diameter. Currently, surgeons intervene when the aneurysm reaches a maximum diameter of 50mm [1]. 200,000 new cases are diagnosed each year in the US, with 500,000 new cases diagnosed worldwide [2]. This results in 15,000 deaths each year from AAA rupture in the US alone [3], with 8,000 deaths per year in the UK [4]. Literature supports the theory that small aneurysms may be as likely to rupture as larger aneurysms [5-7], and therefore, the need for a more reliable predictor of AAA rupture may have clinical importance. Geometrically correct 3D reconstruction of AAAs has become commonplace in the stress analysis of these aneurysms. The purpose of this paper is to show the creation process from patient-specific computed tomography (CT) scans to a patient-specific silicone model. These patient-specific AAA models can then be utilised with various experimental techniques, such as, stress analyses using the photoelastic method [8], fluid dynamic studies, post-operative stent graft distraction testing, and also experimental rupture studies. MATERIALS AND METHODS Three-dimensional models were reconstructed from patient- specific CT scans, using the commercially available software, Mimics (Materialise, Belgium). These geometrically accurate 3D reconstructions allow the creation of polylines, which are then exported to ProEngineer (Parametric Technology Corporation) for mould designs to be used in the lost-wax process manufacturing technique. Designs are converted to numerical code using AlphaCAM, before being machined from solid aluminium block using a three-axis milling machine. This process (see Figure 1) allows the manufacture of patient- tailored AAA moulds. Figure 1. Creation process of patient-specific AAA moulds. Two mould sets are machined for each AAA. One set is used to make the wax cast, using Castylene B851, which is then placed into the larger outer mould. Liquid silicone is then injected into this outer cast and cured in an oven at 40ºC. Once cured, the wax is melted from the silicone model, leaving a silicone replica of the patient-specific AAA. Proceedings of the ASME 2007 Summer Bioengineering Conference (SBC2007) June 20-24, Keystone Resort & Conference Center, Keystone, Colorado, USA SBC2007-176375 3D RECONSTRUCTION OF PATIENT-SPECIFIC ABDOMINAL AORTIC ANEURYSMS: FROM CT SCAN TO SILICONE MODEL Barry J. Doyle (1), Liam G. Morris (1), Anthony Callanan (1), Eamon Kavanagh (1), Pat Kelly (1), David A. Vorp (2) and Tim M. McGloughlin (1) (1) Centre for Applied Biomedical Engineering Research, Materials and Surface Science Institute, University of Limerick, Ireland. (2) Vascular Bioengineering Laboratory, McGowan Institute for Regenerative Medicine, University of Pittsburgh. Downloaded From: http://proceedings.asmedigitalcollection.asme.org/ on 10/13/2014 Terms of Use: http://asme.org/terms