4th Annual Mountain West
Biomedical Engineering Conference

An important issue in bioengineering is understanding average properties of an anatomical structure in different regions across a group of subjects. This requires a common coordinate system or template to which each subject's properties are first mapped and then compared without the bias of individual geometric differences. This work presents a mathematical framework for analyzing such properties. The properties defined on the surface of each structure are specific to that anatomical region for that subject. A common coordinate system is created by averaging the surface to generate a representative surface template. The properties from each of the subjects is mapped on to that representative geometric average of the set. The magnitude and spatial distribution of these properties are then analyzed for this population. This methodology is exemplified in the field of biomechanics for analyzing ten subject-specific finite element (FE) models that are used to predict articular cartilage mechanics in the hip joint during various daily activities. Predicted properties include contact stresses, shear stresses, and cartilage thickness. The representative surface template is partitioned by regions, average values are obtained, and significant differences in stress or thickness is detected for the modeled subjects. Results from this method provides a better understanding of the location based properties across a population of subjects. This framework has the potential to analyze inter-population differences, such as the variations in cartilage stresses between healthy subjects and those with geometrical pathologies (e.g. developmental dysplasia of the hip).