Dissertation/ Thesis
Third Harmonic Transmit Phasing on Contrast Harmonic Imaging
| العنوان: | Third Harmonic Transmit Phasing on Contrast Harmonic Imaging |
|---|---|
| Alternate Title: | 使用三倍頻發射相位法於對比劑諧波影像 |
| المؤلفون: | Hung-wei Wang, 王鴻偉 |
| Thesis Advisors: | Che-Chou Shen, 沈哲州 |
| سنة النشر: | 2008 |
| المجموعة: | National Digital Library of Theses and Dissertations in Taiwan |
| الوصف: | 96 Harmonic detection of ultrasonic contrast agents provides limited contrast-to-tissue ratio (CTR) mainly because of background tissue harmonic signals. To suppress tissue harmonic amplitude, the method of third harmonic (3f0) transmit phasing can be utilized by phasing an additional 3f0 transmit signal to achieve effective cancellation between the frequency-sum component and the frequency-difference component of tissue harmonic signal. For contrast agents, however, our results indicate that the nonlinear responses from microbubbles behaves very differently in 3f0 transmit phasing. Specifically, the suppression phase for contrast microbubble deviates from that for tissue and moreover, the achievable suppression of contrast harmonic signal is markedly reduced. Consequently, with the selection of 3f0 transmit phase that leads to maximal tissue suppression, the CTR can be optimally improved in harmonic imaging. Nevertheless, the CTR improvement in 3f0 transmit phasing can be compromised when the tissue suppression decreases in the presence of spectral leakage. Consequently, multi-pulse sequences such as pulse-inversion are suggested for leakage removal in 3f0 transmit phasing. |
| Original Identifier: | 096NTUS5442081 |
| نوع الوثيقة: | 學位論文 ; thesis |
| وصف الملف: | 87 |
| الاتاحة: | http://ndltd.ncl.edu.tw/handle/13602932453039463554 |
| رقم الانضمام: | edsndl.TW.096NTUS5442081 |
| قاعدة البيانات: | Networked Digital Library of Theses & Dissertations |
| الوصف غير متاح. |