Detection of HIFU-induced coagulation by motion-compensated decorrelation of RF echo signals

Correlation between the ultrasonic echoes has been used to detect the changes of the tissue during high-intensity focused ultrasound (HIFU) exposure, but it tends be lost when tissue coagulation has progressed. In this study, the loss of correlation itself is utilized to detect the tissue coagulation while compensating the local tissue motion. In the experiment with freshly excised and degassed porcine Iiver, localized decrease in correlation was observed at and around the HIFU focus. The area of decorrelation between each adjacent two frames, separated about 1 s, agreed weil with the actual lesion.