Small calcification indicator in ultrasonography using correlation of echoes with a modified Wiener filter.

Abstract

The purpose of this study is to improve the calcification depiction ability in ultrasonography using correlation of echoes with a modified Wiener filter. The waveform of an ultrasound pulse changes when it passes through the location of a calcification. Since the change in echo waveform caused by a calcification decreases the correlation of waveforms in adjacent scan lines, we have proposed a calcification depiction method using the decorrelation of echoes. However, the low signal-to-noise ratio of echoes also decreases the correlation of the echoes. In this study, we employ the correlation of echoes with a modified Wiener filter to suppress the effect of noise, as an indicator of a calcification. The proposed calcification indicator depicted copper cylindrical rods 0.2mm in size at a depth of 2cm with a sensitivity of 80% and a positive predictive value of 80%, despite being hardly depicted at all on B-mode ultrasound imaging. This study suggests the potential of the proposed method to improve the performance of calcification depiction by ultrasound devices.