A comparison between BEM and FEM for elastic registration of medical images

The aim of medical image registration is to bring different images into the best possible spatial correspondence in order to obtain complementary information for clinical applications. When using physically-based techniques for image registration the transformation of images is typically obtained as the solution of partial differential equations of continuum mechanics. Because of the complexity of real boundary conditions, these equations can usually be solved with the help of numerical techniques only. One standard numerical method is the boundary element method (BEM) which allows to compute the solution exclusively through boundary integration. This paper investigates the applicability of BEM for registration of medical images and quantitatively assesses its advantages and disadvantages in comparison to the previously used finite element method (FEM). q 2006 Elsevier B.V. All rights reserved.