Utilizing deformable image registration to create new living human heart models for imaging simulation
The Living Heart Model (LHM) was developed as part of the Living Heart Project by Dassault Systemes to provide a numerical finite element (FE) model of the human heart that accurately reproduces the normal cardiac physiology. We previously incorporated the LHM into the 4D extended cardiac-torso (XCAT) phantom for imaging research, rigidly transforming the model to fit it within different anatomies. This captured the variation in the overall size, position, and orientation of the heart but did not capture more subtle geometrical changes. Anatomic measurements of normal heart structures can show standard deviation variations of upwards of 25-30%. In this work, we investigate the use of Hyperelastic Warping to non-rigidly fit the LHM to new anatomies based on 4D CT data from anatomically diverse, normal patients. For each patient target, the mid-diastolic frame from the CT (heart is most relaxed) was segmented to define the cardiac chambers. The geometry of the LHM was then altered to match the targets using Hyperelastic Warping to register the LHM mesh, in its relaxed state, to each segmented dataset. The altered meshes were imported back into the FE software to simulate cardiac motion from the new geometries to incorporate into the XCAT phantom. By preserving the underlying LHM architecture, our work shows that Hyperelastic Warping allows for efficient revision of the LHM geometry. This method can produce a diverse collection of heart models, with added interior variability, to incorporate into the XCAT phantom to investigate 4D imaging methods used to diagnose and treat cardiac disease.
