Assessment of regional myocardial strain by a novel automated tracking system from digital image files

Myocardial strain imaging by Doppler tissue echocardiography is a useful method to quantify regional left ventricular function. However, this method has a problem of its Doppler angle dependency. We attempted to quantify myocardial strain by a newly developed automated tracking system from digital image files. In 6 anesthetized open-chest dogs, a pair of ultrasonic crystals was implanted at the inner site and outer site of the left ventricular wall to measure myocardial radial strain. B-mode echocardiographic images and trajectories of crystals were recorded simultaneously. Three conditions were examined by intravenous infusion of dobutamine. We used a pattern matching algorithm, which allowed us to track objects from one frame to the next. In 18 image sequences obtained in the 6 dogs, there was an excellent correlation in maximal myocardial strain between the two methods ( r = 0.92, P < .0001). Thus, this system is a promising tool to provide automated quantification of regional myocardial strain.