DocumentCode :
1063946
Title :
Third Harmonic Transmit Phasing for Tissue Harmonic Generation
Author :
Shen, Che-Chou ; Wang, Yu-Chun ; Hsich, Y.-C.
Author_Institution :
Nat. Taiwan Univ. of Sci. & Technol., Taipei
Volume :
54
Issue :
7
fYear :
2007
fDate :
7/1/2007 12:00:00 AM
Firstpage :
1370
Lastpage :
1381
Abstract :
Generation of tissue harmonic signals during acoustic propagation is based on the combined effect of two different spectral interactions of the transmit signal. One produces harmonic whose frequency is the sum of transmit frequencies. The other results in harmonic at difference frequency of the transmit signals. Both the frequency-sum component and the frequency-difference component are sensitive to the phase of their constitutive spectral signals. In this study, a novel approach for modifying the amplitude of tissue harmonic signal is proposed based on phasing these two components to achieve either harmonic enhancement or suppression. Both experiments and simulations were performed to investigate the effects of 3fo transmit phasing on tissue harmonic generation. Results indicate that the relative phasing between the frequency-sum component and the frequency-difference component markedly changes the amplitude of the second harmonic signal. For harmonic enhancement, approximate 6 dB increase of second harmonic amplitude can be achieved while the lateral harmonic beam pattern also is improved as compared to conventional situations in which only the frequency-sum component is considered. For harmonic suppression, the second harmonic signal also could be significantly reduced by about 11 dB when the frequency-difference component is out of phase with the frequency-sum component. Hence, the method of 3fo transmit phasing has potentials for both improving signal-to-noise ratio in tissue harmonic imaging and enhancing image contrast in contrast-agent imaging by suppression of tissue harmonic background.
Keywords :
bioacoustics; biological effects of acoustic radiation; biological tissues; harmonic generation; acoustic propagation; frequency-difference component; frequency-sum component; harmonic enhancement; harmonic suppression; signal-noise ratio; third harmonic transmit phasing; tissue harmonic generation; Acoustic beams; Acoustic distortion; Acoustic imaging; Acoustic propagation; Frequency conversion; Harmonics suppression; Image quality; Nonlinear acoustics; Power system harmonics; Signal to noise ratio; Algorithms; Image Enhancement; Image Interpretation, Computer-Assisted; Reproducibility of Results; Sensitivity and Specificity; Ultrasonography;
fLanguage :
English
Journal_Title :
Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on
Publisher :
ieee
ISSN :
0885-3010
Type :
jour
DOI :
10.1109/TUFFC.2007.397
Filename :
4277153
Link To Document :
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