Myocardial strain analysis of echocardiographic sequences using nonrigid registration

This paper proposes a new method to compute the 2D strain tensor from gray-scale 2D echocardiographic sequences and presents a clinical trial to test its applicability to regional analysis of the left ventricle. Myocardial motion is computed using spatio-temporal nonrigid registration techniques on the whole sequence. The key feature of our method is the use of an analytical representation of the myocardial displacement field based on a semilocal parametric model of the deformation using Bsplines. The strain tensor is therefore obtained from the analytical expression of the spatial gradient of the displacement field. Robustness and speed are achieved by introducing a multiresolution-optimization strategy. To test the clinical applicability of our method we applied the algorithm to the regional analysis of the left ventricle, and obtained significant differences between normal and pathological segments.