Use Of Medical Image Data To Compute Strain Fields In Biological Tissue

INTRODUCTION Medical images, such as magnetic resonace (MR) or computed tomography (CT), provide measures of the three dimensional distribution of physical properties within tissues. Under the action of applied loads, the distribution is transformed such that images interrogated from the deformed tissues are not identical to those from the reference state. Part of this transformation is due to convection of material through fixed Eularian observation points of the imager and part is due to Lagrangian changes in the physical properties of the material. In the case of CT, for example, image intensity data is closely related to tissue density. During deformation, material points of differing density convect through image voxels while simultaneously changing density values according to the volume ratio. This type of data thereby provides a powerful constraint that can be employed to reconstruct three-dimensional strain fields in tissues. In the present work a time sequence of MR i