A novel postprocessing method successfully reconstructed continuous 3D displacement and strain fields from DENSE MRI data, revealing detailed local myocardial deformation differences between normal and infarcted sheep ventricles.
A novel postprocessing method for DENSE MRI enables continuous 3D reconstruction of myocardial tissue motion and strain, extending its utility for patient-specific cardiac mechanics modeling.
A quantitative analysis of myocardial mechanics is fundamental to understanding cardiac function, diagnosis of heart disease, and assessment of therapeutic intervention. Displacement encoding with stimulated-echo (DENSE) magnetic resonance imaging (MRI) technique was developed to track the three-dimensional (3D) displacement vector of discrete material grid points in the myocardial tissue. Despite the wealth of information gained from DENSE images, the current software only provides two-dimensional in-plane deformation. The objective of this study is to introduce a postprocessing method to reconstruct and visualize continuous dynamic 3D displacement and strain fields in the ventricular wall from DENSE data. An anatomically accurate hexagonal finite-element model of the left ventricle (LV) is reconstructed by fitting a prolate spheroidal primitive to contour points of the epi- and endocardial surfaces. The continuous displacement field in the model is described mathematically based on the discrete DENSE vectors using a minimization method with smoothness regularization. Based on the displacement, heart motion and myocardial stretch (or strain) are analyzed. Illustratory computations were conducted with DENSE data of three infarcted and one normal sheep ventricles. The full 3D results show stronger overall axial shortening, wall thickening, and twisting of the normal LV compared with the infarcted hearts. Local myocardial stretches show a dyskinetic LV in the apical region, dilation of apex in systole, and a compensatory increase in strain in the healthy basal region as a compensatory mechanism. We conclude that the proposed postprocessing method significantly extends the utility of DENSE MRI, which may provide a patient-specific 3D model of cardiac mechanics.
Liu et al. (Sat,) conducted a other in Myocardial infarction (animal model) (n=4). 3D continuous displacement and strain field reconstruction from DENSE MRI vs. Normal sheep (for illustration) was evaluated on Reconstruction of continuous 3D displacement and strain fields. A novel postprocessing method successfully reconstructed continuous 3D displacement and strain fields from DENSE MRI data, revealing detailed local myocardial deformation differences between normal and infarcted sheep ventricles.