Needles A, Couture O, Foster F S
Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
Ultrasound Med Biol. 2009 Sep;35(9):1564-73. doi: 10.1016/j.ultrasmedbio.2009.04.006. Epub 2009 Jul 25.
This study introduces a new method for differentiating targeted microbubbles in the presence of flowing microbubbles and tissue using micro-ultrasound. The method relies on subharmonic (SH) imaging for segmenting microbubble signals from tissue signals, and low-pass interframe filtering for segmenting bound targeted microbubbles from flowing microbubbles. The method is evaluated with 30 frames per second SH B-mode imaging in vitro, using a wall-less vessel flow phantom. The SH B-mode cineloops were postprocessed using an interframe moving average filter to segment the regions of bound microbubbles on the inner surface of the vessel phantom. The bound bubbles were then disrupted with sufficiently high ultrasound pressures, so that the dynamic process of targeted microbubble binding under flowing conditions could be observed. These preliminary results show that the proposed method is a feasible solution to the challenge of differentiating targeted microbubbles in the presence of tissue and freely flowing microbubbles at high frequencies, which in turn should improve the specificity of targeted microbubble detection.
本研究介绍了一种利用微超声在存在流动微泡和组织的情况下区分靶向微泡的新方法。该方法依靠次谐波（SH）成像从组织信号中分割微泡信号，并依靠低通帧间滤波从流动微泡中分割结合的靶向微泡。使用无壁血管流动模型，在体外以每秒30帧的SH B模式成像对该方法进行评估。使用帧间移动平均滤波器对SH B模式电影环进行后处理，以分割血管模型内表面上结合微泡的区域。然后用足够高的超声压力破坏结合的气泡，以便观察流动条件下靶向微泡结合的动态过程。这些初步结果表明，所提出的方法是应对在高频下存在组织和自由流动微泡时区分靶向微泡这一挑战的可行解决方案，这反过来应能提高靶向微泡检测的特异性。
