Measuring the internal geometry of an anastomosed synthetic blood vessel under internal pressure

Abstract

For this paper, a simple inexpensive rig system was designed and two methods for imaging and measuring how a synthetic representation of an anastomosed artery deforms under internal pressure were used. An optical method with a camera and a Computed Tomography (CT)-based imaging method were used. Cylindrical samples of Natural Rubber Latex were anastomosed and subject to extension-inflation tests to represent an artery under the physiological conditions of the body. The simple rig system was designed to apply physiological levels of internal pressure to the latex tubing. The two imaging methods were used to monitor variations in the circumferential and longitudinal extension as a function of the applied pressure. The CT scanner has the additional ability to view inside the specimen and give an understanding of how the tension in the sutures affects the internal and external shape of the specimen. The two methods, optical and CT, were compared to each other and to theoretical predictions to assess the potential limitations of each of these methods. Quantifying and understanding the material properties of the synthetic representation used proved to be an imperative part of the investigation to predict and understand how the specimen would deform. In conclusion, the CT measurements were likely to provide the most reliable results. Departures in the measurements from theoretical predictions means that empirical methods should continue to be applied to studies modelling anastomosed arteries and used to improve theoretical predictions.