Estimation of Eulerian strain from tagged MRI using Optical flow

Cardiac magnetic resonance imaging (MRI) is considered as noninvasive imaging modalities provide information on myocardial function, viability, and morphology. One of the most common MRI techniques is tagging MRI, based on this technique the deformation of the myocardium can be evaluated and some of cardiac functions can be examined. The strain of cardiac muscle one of the parameters estimated based on the estimated deformation, this estimated strain help in the examination of myocardium viability. This paper presents a mathematical model that simulates the real cardiac motion during myocardial tagging. Using this model and real data, we estimate the circumferential strain using strain tensor with Band-pass Optical flow (BPOF) technique and compare it with the estimated strain of Harmonic Phase (HARP as a golden standard technique. The results exhibit that the stain can be estimated using BPOF method with the same level of accuracy compared to HARP method, however, BPPOF provides more reliable results than HARP, with no tracking errors, at the myocardial boundaries.