Three-dimensional myocardial deformations: Calculation with displacement field fitting to tagged MR images

PURPOSE: To reconstruct three-dimensional (3D) myocardial deformations from orthogonal sets of parallel-tagged magnetic resonance (MR) images. MATERIALS AND METHODS: Displacement information in the direction normal to the undeformed tag planes was obtained at points along tag lines. Three independent sets of one-dimensional displacement data were used to fit an analytical series expression to describe 3D displacement as a function of deformed position. The technique was demonstrated with computer-generated models of the deformed left ventricle with data from healthy human volunteers. RESULTS: Model deformations were reconstructed with a 3D tracking error of less than 0.3 mm. Error between estimated and observed one- dimensional displacements along the tags in 10 human subjects was 0.00 mm ± 0.36 (mean ± standard deviation). Robustness to noise in the tag displacement data was demonstrated by using a Monte Carlo simulation. CONCLUSION: The combination of rapidly acquired parallel-tagged MR images and field-fitting analysis is a valuable tool in cardiac mechanics research and in the clinical assessment of cardiac mechanical function.