Disease Modeling: In-Vivo Aneurysm Analysis in 3D
An interesting application of 3D Printing & visualization software is disease modeling. For example, the development of aortic aneurysms, life-threatening dilations of the aorta, is affected by a wide range of environmental and genetic factors. Therefore, aortic aneurysms are difficult to study clinically and experimentally. A team of researchers at the University of Rochester, New York, including Dr. Ankur Chandra, Associate Professor of surgery and biomedical engineering and a practicing vascular surgeon himself, took the challenge.
“Based on patient CT data, we start by creating a patient-specific 3D model of an aneurysm,” Dr. Chandra explains. “Next, we print it using a biologically accurate material that simulates the properties of the aortic wall, and then we mount it on a hemodynamic simulator, subjecting it to such tightly controlled hemodynamic parameters as intraluminal pressures, blood flows, and cardiac outputs.” This allows the researchers to study aneurysm behavior under varying conditions. Before, most aneurysm research was performed in animals. Studying human aneurysms raises ethical concerns, as ruptures are mostly fatal.
Five steps involved in creating and testing a 3D-printed model of an AAA: A. 3-D reconstruction of a patient-specific aneurysm in .stl format generated using Mimics software; B. ABS model of the inner and outer lumens of the aneurysm created using 3D printing; C. Matlab-generated heat map of the aneurysm undergoing wall strain; D. PVA cryogel phantom of the aneurysm mounted and pressurized on a hemodynamic simulator; E. high-speed video of the initial fracture and rupture point of the aneurysm during testing. Images courtesy of the University of Rochester, New York.
3D Printing technology also has a positive impact on vascular device design and testing. “With the ability to 3D print aortic pathology, we will eventually be able to test many aortic devices in an ex vivo environment,” Dr. Chandra says. “By implanting them into anatomy and physiology similar to those of humans suffering from aneurysms, we will be able to observe how these devices behave.” The technology can also be useful in developing technologies for aortic dissection, a procedure which is nearly impossible to test in animals.
“Aneurysms, Dr. Chandra comments, “are a low-prevalence, high-mortality disease. While they don’t affect huge patient populations, as do hypertension and diabetes, the mortality rate associated with the untreated disease is very high. It therefore falls into the category of a disease in which risk prediction and screening are crucial. Not everyone has it, but for those that do, we need to figure it out.”