Adaptive stretch factor method based on moving window for ultrasound elasticity imaging

The changes of tissue elasticity are often related to their lesions. Therefore elastography is helpful to diagnosis. Adaptive stretch factor method for ultrasound elasticity imaging adaptively finds out the stretch factors that can maximize the correlation between the pre- and post-compressed RF signals by iteratively stretching the latter one, and the tissue strain image is obtained. This method produces images with less noise, but the imaging efficiency is low.The window moving is added to simplify the calculations of the cross-correlation function, and an adaptive stretch factor method based on moving window for ultrasound elasticity imaging is proposed. In the new method, only the cross-correlation factors with delay time of 0 are calculated, which improves the efficiency of the method. The modified method was tested with simulated RF data, and the results show that the proposed method can provide elasticity images with less noise, from which the hard lesions with diameter of larger or equal to 4 mm can be seen when the total strain range is from 2% to 5%. Besides, according to the statistics of the program running time, the modified method is obviously more efficient.