Calculus detection for ultrasonography using decorrelation of forward scattered wave.
OBJECTIVE
The purpose of this paper is to propose a novel strategy to detect small calculi efficiently.


METHODS
The proposed calculus detection strategy focuses on decorrelation of forward scattered waves caused by the failure of Born's approximation. A calculus causes waveform changes of transmit pulses, resulting in a decrease in the cross-correlation coefficients calculated from IQ signals scattered near the calculus position. Therefore, we can detect calculi from the appearance of dips in correlation coefficients.


RESULTS
When a calculus exists in a digital tissue map, sharp and deep dips in cross-correlation coefficients between acoustic IQ signals appear around the calculus. By contrast, no apparent dip exists when a tissue map contains no calculus. A scan line interval of 0.2 mm or less is appropriate for the conditions simulated in this paper, and the proper transmit focal range for the proposed method is at a calculus range.


CONCLUSIONS
These results imply that the proposed strategy can improve the efficiency of US devices for small calculus detection.
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, Yoshida-honmachi, Sakyo-ku, Kyoto, 606-8501, Japan.
Makoto
M
Yamakawa
Graduate School of Medicine, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto, 606-8501, Japan.
Tsuyoshi
T
Shiina
Graduate School of Informatics, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto, 606-8501, Japan.
Toru
T
Sato
CFAR; Calculus detection; Decorrelation; Forward scattered wave; Ultrasonography