Abstract
Advanced clinical diagnosis of a cardiac function requires quantitative evaluation of myocardium deformation. It is however still challenging to quantify myocardium deformations due to noises caused by entire cardiac movements and limits of imaging modalities. Here, we propose a novel method for gaining strain rates of myocardium with better spatiotemporal accuracy compared with conventional methods. The proposed method is based on the theory of geometrical constraints which provides a deformation gradient tensor to relate undeformed to deformed configuration of an object. The deformed configuration of the left ventricle was estimated from the present configuration and velocity data obtained by phase contrast (PC)-MR imaging. The proposed method has two major advantages. First, because of no need to use temporally sequential images in estimating velocity as in conventional methods, strain rates calculated from the proposed method are basically free from temporal resolutions of imaging modalities. Second, because of unnecessity of spatially interpolating data, calculated strain rates retain the same spatial resolution as PC-MR images. On comparing a spatial field of strain rates obtained with the proposed method to that with a conventional method, we found that the proposed method was capable of providing spatially smoother field of strain rates in the left ventricular myocardium.
