Strain and strain rate deformation parameters: from tissue Doppler to 2D speckle tracking.

Strain and strain rate deformation parameters based on Color Doppler Myocardial Imaging, and more recently on two-dimensional (2D) gray scale images, have evolved as important methods for the quantification of myocardial function. Although these parameters are already applicable in the research field, their acquisition and analysis involve a number of technical challenges and complexities. Accurate knowledge of the basic principles of those techniques, as presented in this article, will further enhance their applicability to clinical practice.