Meshless deformable models for 3D cardiac motion and strain analysis from tagged MRI

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Computational Mechanics

Background:

• Tagged magnetic resonance imaging (TMRI) visualizes myocardial deformation noninvasively.
• Accurate 3D cardiac motion tracking requires sophisticated 3D deformable models.
• Through-plane motion necessitates advanced methods for 3D trajectory and strain computation.

Purpose of the Study:

• To develop and validate a novel meshless deformable model (MDM) for 3D cardiac motion reconstruction.
• To enable precise computation of 3D strain fields from TMRI data.
• To assess the performance of MDM against established methods.

Main Methods:

• Utilized intersections of orthogonal tagging planes as control points for a volumetric MDM.
• Registered a generic heart mesh to TMRI data using polar decomposition.
• Deformed the MDM using MR image tagging lines, iteratively minimizing Laplacian coordinates.
• Computed 3D strain fields from displacement fields using moving least squares.

Main Results:

• MDMs demonstrated superior performance compared to finite element and spline methods on a numerical phantom.
• The model successfully tracked material point trajectories and computed 3D strain fields.
• In vivo experiments on healthy and patient heart MRI confirmed MDM's ability to fully recover 3D myocardium motion.

Conclusions:

• Meshless deformable models offer a robust approach for 3D cardiac motion and strain analysis from TMRI.
• MDM provides accurate, noninvasive quantification of myocardial deformation.
• This technique has significant potential for clinical applications in cardiac diagnostics.