Speckle Tracking Techniques:
This is another group of advanced imaging techniques, again at the time of writing they are a research rather than a clinical tool. While the signal received from an ultrasound scan of a thickness of myocardium may appear to be a random series of speckles, in fact the signal is generated by overlapping sheaths of fibres. Therefore signal is not randomly generated, rather it represents a ‘fingerprint’ of myocardium. Advanced post-processing techniques can now be used to track these speckles through the cardiac cycle, and again measure strain and strain rate.
These techniques are not vulnerable to angle of insonation, but do still require high quality images for processing.