A left ventricular finite element mesh fitted to the geometry of a human LV is deformed by fitting the mesh to manually tracked data points in 3D MRI (untagged) images. Distinct features in the images have been traced by placing a data-point (fiducial marker) on it from frame to frame. The material point that one such marker correspond to in time-frame 1 will generally move out of the image-plane for frame n, where n>1. The tracked marker is considered an approximation of the projection of the material point onto the image-plane. The coordinates of each marker is given in the data-files where the last three columns are the elements of the image plane normal for each corresponding marker.

The motion of the mesh is fitted to the displacements of these tracked markers, but if the predicted material point moves out of the image-plane, the error-component along the image-plane normal is ignored.

As the tracked points most often lie outside or on the LV FE model walls the LV mesh is embedded in a larger host mesh. The host mesh also embeds the fiducial markers. The fitting procedure is applied to the host mesh and then the LV mesh is updated inside the host mesh.

For more details see paper "Parameter distribution models for estimation of left ventricular deformation using sparse fiducial markers", submitted 2003.

Created by Espen Remme April 2004.