Tissue Dependent Registration

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  Projects List

• FEMMesh2.jpg

  Slice of a label dependent tetrahedral mesh.

Key Investigators

• Petter Risholm (PhD Student, Harvard Medical School (BWH), University of Oslo)
• William Wells (Professor, Harvard Medical School (BWH) )

Objective

Most registration methods treat tissue parameters as uniform over the image domain. For instance, when brain tissue is modeled as an elastic material, identical stiffness parameters are used for all tissue types (CSF, GM, WM). We let different tissue types take on varying stiffness parameters, so we can thereby optimize the deformation as well as the stiffness parameters at the same time. Our approach models the tissue with a linear elastic Finite Element (FE) model and solve for the linear elastic tissue parameters as well as the deformation through a Markov Chain Monte Carlo process.

However, to accurately model the tissue, we require a tissue dependent tetrahedral mesh. Assuming we have a segmentation of the brain tissue into CSF, GM and WM, we need a mesh where the tetrahedra conform to the different tissue types (the edges of a tetrahedra do not cross from one tissue type to the other but are either fully within a tissue type or on the boundary between two tissue types).

Approach, Plan

Find/Develop mesher that generates elements conforming to a labelmap.

Utilize command line tools to visualize the registration results.

Progress