Eckersley Robert J, Chin Chien Ting, Burns Peter N
Imaging Sciences Department, Imperial College, London, UK.
Ultrasound Med Biol. 2005 Feb;31(2):213-9. doi: 10.1016/j.ultrasmedbio.2004.10.004.
A series of in vitro experiments were performed to determine the efficacy of generalised phase- and amplitude-modulated sequences for low-power nonlinear microbubble contrast imaging. The microbubble agent Definity (Dupont, Boston, MA) was exposed to sequences in which the phase and amplitude were changed from one pulse to the next. Echoes from these pulses were combined to suppress or enhance particular linear or nonlinear components. The results show that established two-pulse pulse-inversion and amplitude-modulation approaches perform similarly, providing 14 +/- 1 dB of enhancement, compared with the echoes from the linear scatterer. A two-pulse combined phase and amplitude sequence achieved an additional 4 +/- 1 dB of enhancement. This improvement is due to improved preservation of second and third order harmonic signals, while maintaining the suppression of the linear signals. These results were obtained at low power, below the threshold of microbubble destruction, and are applicable to real-time perfusion imaging.
进行了一系列体外实验，以确定广义相位和幅度调制序列用于低功率非线性微泡造影成像的效果。将微泡剂Definity（杜邦公司，马萨诸塞州波士顿）暴露于相位和幅度从一个脉冲到下一个脉冲发生变化的序列中。来自这些脉冲的回波被组合起来，以抑制或增强特定的线性或非线性成分。结果表明，既定的双脉冲脉冲反转和幅度调制方法表现相似，与来自线性散射体的回波相比，可提供14±1dB的增强效果。双脉冲组合相位和幅度序列实现了额外4±1dB的增强。这种改进归因于在抑制线性信号的同时，更好地保留了二阶和三阶谐波信号。这些结果是在低于微泡破坏阈值的低功率下获得的，适用于实时灌注成像。
