Small calcification indicator in ultrasonography using correlation of echoes with a modified Wiener filter.
OBJECTIVE
The purpose of this study is to improve the calcification depiction ability in ultrasonography using correlation of echoes with a modified Wiener filter.


METHODS
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.


RESULTS
The proposed calcification indicator depicted copper cylindrical rods 0.2 mm in size at a depth of 2 cm with a sensitivity of 80% and a positive predictive value of 80%, despite being hardly depicted at all on B-mode ultrasound imaging.


CONCLUSIONS
This study suggests the potential of the proposed method to improve the performance of calcification depiction by ultrasound devices.
Graduate School of Informatics, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto, 606-8501, Japan. hirofumi.taki@mb6.seikyou.ne.jp.
Hirofumi
H
Taki
Graduate School of Informatics, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto, 606-8501, Japan.
Takuya
T
Sakamoto
Advanced Biomedical Engineering Research Unit, Kyoto University, Kyoto, Japan.
Makoto
M
Yamakawa
Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Tsuyoshi
T
Shiina
Graduate School of Informatics, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto, 606-8501, Japan.
Toru
T
Sato
Calcification; Calcification depiction; Decorrelation; Ultrasonography; Wiener filter