Non-Doppler two-dimensional strain imaging by echocardiography--from technical considerations to clinical applications.

During the past several years, strain and strain rate imaging have emerged as a quantitative technique to accurately estimate myocardial function and contractility. Non-Doppler, 2-dimensional (2D) strain imaging is a new echocardiographic technique for obtaining strain and strain rate measurements. It analyzes motion by tracking speckles in the ultrasonic image in two dimensions. Current available software allows spatial and temporal image processing with recognition and selection of such elements on ultrasound image. The geometric shift of each speckle represents local tissue movement. By tracking theses speckles, 2D tissue velocity, strain, and strain rate can be calculated. Non-Doppler 2D strain imaging is simple to perform. It requires only one cardiac cycle to be acquired; further processing and interpretation can be done after image data acquisition. Because it is not based on tissue Doppler measurements, it is angle independent. Data regarding accuracy, validity, and clinical application of non-Doppler 2D strain imaging are rapidly accumulating. This technique may prove to be of significant clinical value, enabling rapid and accurate assessment of global and segmental myocardial function.