Leavens Claudia, Williams Ross, Foster F Stuart, Burns Peter N, Sherar Michael D
Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada.
IEEE Trans Ultrason Ferroelectr Freq Control. 2007 Oct;54(10):2082-90. doi: 10.1109/tuffc.2007.503.
We present a technique that uses Golay phase encoding, pulse inversion, and amplitude modulation (GPIAM) for microbubble contrast agent imaging with ultrasound. This technique improves the contrast-to-tissue ratio (CTR) by increasing the time-bandwidth product of the insonating waveforms. A nonlinear pulse compression algorithm is used to compress the signal energy upon receive. A 6.5-dB improvement in CTR was observed using an 8-chip GPIAM sequence compared to a conventional pulse-inversion amplitude-modulation sequence. The CTR improvement comes at the cost of a reduction in frame rate: GPIAM coding uses four input pulses whereas most contrast imaging sequences require two or three pulses. Our results showed that the microbubble response can be phase encoded and subsequently compressed using a nonlinear matched-filtering algorithm, in order to enhance the signal from the contrast agent, while maintaining resolution and suppressing the tissue signal.
我们提出了一种利用格雷编码相位编码、脉冲反转和幅度调制（GPIAM）进行超声微泡造影剂成像的技术。该技术通过增加发射波形的时间带宽积来提高对比组织比（CTR）。在接收时使用非线性脉冲压缩算法来压缩信号能量。与传统的脉冲反转幅度调制序列相比，使用8芯片GPIAM序列观察到CTR提高了6.5dB。CTR的提高是以帧率降低为代价的：GPIAM编码使用四个输入脉冲，而大多数对比成像序列需要两个或三个脉冲。我们的结果表明，微泡响应可以进行相位编码，随后使用非线性匹配滤波算法进行压缩，以增强来自造影剂的信号，同时保持分辨率并抑制组织信号。
