Speckle tracking echocardiography is a new player in the cardiac arena which is rapidly making its mark in cardiac and radiology circles alike. It is an objective, robust, semiautomatic and reproducible technique with a short post processing time.
Traditionally, left ventricular function is measured through M-mode, 2-Dimensional (2D) and more recently 3-Dimensional (3D) echocardiography, while the flow and velocities are measured on Colour Doppler echocardiography. Volumes, mass and ejection fraction are the most common indices of ventricular function through these techniques. However, these indices are highly dependent on either preload, afterload or both. The assessment of cardiac function that we get is global with very little information on regional cardiac function. Though regional cardiac function can be assessed through wall motion score index (WMSI) and similar indices, it is highly subjective and observer dependent.
Speckles are small scattered waves of very small wavelength which are usually considered "noise" in the system and give the image appearance of "blob" or "speckle" pattern. In speckle tracking echocardiography, these speckles are grouped into small number of pixels and assigned "kernel" function. These speckles are then traced from one point to another as the heart contracts and expands. These algorithms give a complete fingerprint of the motion and deformation of the myocardium throughout cardiac cycle.
Most custom software measure the parameters of movement (velocity and displacement) and deformation (strain and strain Rate). strain, broadly speaking, is the change in length of an object relative to its original length and is given by L-Lo/Lo.
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