Clinical assessment of real-time, freehand elasticity imaging system based on the combined autocorrelation method

Various techniques for tissue elasticity imaging have been proposed in the last decade. For clinical applications, real-time and freehand manipulation of a probe is required. In a previous study, we developed the Combined Autocorrelation Method (CAM), which produces an elasticity image with high-speed processing and accuracy, and achieves a wide dynamic range for strain estimation. In the current study, we extended the CAM clinical uses to be robust for tissue sideslip and suited to freehand compression. We achieved this imaging system by adopting its algorithm and using a commercial ultrasonic scanner and a PC. The echo signals are captured in real time and the strain image frame rate was 10 frames/s. Strain images are superimposed on B-mode images with a translucent color scale. In the clinical measurement, elasticity images for breast and prostate cancer were obtained from more than 50 subjects. Some results yielded an elasticity image, that is, a visualization of the tumor area and detected a non-invasive ductal carcinoma. These results demonstrate that the system can provide high-quality and stable elasticity images in clinical measurement.