Direct calculation of 2D components of myocardial strain using sinusoidal MR tagging

A new technique to measure local planar strain in left ventricular myocardium using two-dimensional tagged MR images is presented. This new technique is computationally fast, is fully automated, and generates dense motion estimates. It is based on using a 1-1 SPAMM tag pattern which comprise several one-dimensional sinusoidal tag patterns at different frequencies. A local deformation of the myocardium produces a variation in the local frequencies of these patterns, which can be used to compute strain components in the image plane. Local frequency is measured by scanning certain spectral peaks to create complex images, for which the local frequency is the gradient of the angle associated with their complex data points. The method is demonstrated using both simulations and real tagged MR images, and a discussion of these results and of directions for future research is provided.