Calculation of strain values from strain rate curves: how should this be done?

The noninvasive quantification of regional myocardial function is an important goal in clinical cardiology. Myocardial strain and strain rate indices are two methods of attempting to define regional myocardial function. Several approaches to extract these indices have been proposed in the literature, one of which is to extract the strain rate information as the spatial gradient in myocardial velocities that had been estimated using Doppler myocardial imaging techniques. In order to obtain information on the strain profile, the strain rate curve is time integrated. In practice however, the strain rate curves can be post-processed in several ways and different strain indices can be extracted. As no information exists on which scheme is advantageous, this paper attempts to define the optimal post-processing scheme for the clinical setting.