["INVESTIGATING THE INTERNAL STRESS/STRAIN STATE OF THE FOOT USING MAGNETIC RESONANCE IMAGING AND FINITE ELEMENT ANALYSIS"]

by Marc Thomas Petre It is known that mechanical forces acting within the soft tissues of the foot can contribute to the formation of neuropathic ulcers. Unfortunately, only surface measurements (plantar pressure) are used clinically to estimate foot risk due to mechanical loading. In the absence of equipment to monitor the internal stress and strain states, it is currently unknown how these surface measurements relate to what is happening inside of the foot. Magnetic resonance imaging (MRI) has the potential to provide high resolution in vivo images of the internal structure of the foot. When combined with a device capable of applying loads to the limb during imaging, MRI can be used to visualize 3-dimensional internal strains. If the load applied during imaging is known, finite element models can be used to estimate the internal stress state which corresponds to the visualized deformation. This dissertation describes the development and use of an MRI-compatible loading device to perform an in vivo load-deformation experiment on the human forefoot, a common site of neuropathic ulceration. The collected loaddisplacement field data was used in conjunction with a novel, 3-dimensional, Abstract