Small calcification depiction in ultrasound B-mode images using decorrelation of echoes caused by forward scattered waves

The purpose of this study is to propose a novel method to depict small calcifications in ultrasound B-mode images using decorrelation of forward scattered waves with no decrease in the frame rate. Since the waveform of an ultrasound pulse changes when it passes through a calcification location, the echo waveform from regions behind the calcification is quite different from that without a calcification. This indicates that the existence of a calcification is predictable based upon the waveform difference between adjacent scan lines by calculating cross-correlation coefficients. In addition, a high-intensity echo should return from the calcification itself. Therefore, the proposed method depicts the high-intensity echo positions with posterior low correlation coefficient regions. Eleven of 15 wires 0.2-0.4 mm in diameter were depicted using this method, yielding a sensitivity of 73.3% and a specificity of 100%, even though they might go undetected under clinical inspection of ultrasound B-mode images. This study suggests that an US device could perform well in terms of calcification detection.