Abstract:
"Quantification of 3D Left Ventricular Deformation using Hyperelastic Warping: Comparisons between MRI and PET Imaging"
This study introduces and validates a novel biomechanical technique called Hyperelastic Warping for quantifying the three-dimensional (3D) deformation of the left ventricle (LV) from medical images without fiducial markers. The method uses image-based finite element (FE) analysis, where differences in pixel intensity between a "template" (e.g., end-systole) and "target" (e.g., end-diastole) image are used to generate a body force that deforms a hyperelastic FE model of the LV from one state to the other. This process allows for the direct calculation of tissue strain. To validate the technique's accuracy, a known deformation was first applied to a baseline MRI dataset using a standard "forward" FE analysis to create a synthetic target image. The strains computed by the Warping algorithm showed excellent agreement with the known strains from the forward model, confirming its efficacy. Furthermore, the study applied the Warping analysis to both MRI and Positron Emission Tomography (PET) images from the same patient. The results demonstrated that the fiber stretch distributions calculated from both imaging modalities were highly similar. This finding is significant because it shows that quantitative biomechanical data like strain can be successfully extracted from imaging modalities like PET, which cannot be physically tagged, thereby expanding the tools available for assessing regional heart function.
