Niu Lili, Wang Jing, Qian Ming, Zheng Hairong
Northeastern University, Sino-Dutch Biomedical and Information Engineering, Shenyang, China.
Annu Int Conf IEEE Eng Med Biol Soc. 2009;2009:487-90. doi: 10.1109/IEMBS.2009.5332552.
Developments of many cardiovascular problems have been shown to have a close relationship with arterial flow conditions. An ultrasound-based particle image velocimetry technique(Echo PIV) was recently developed to measure multi-component velocity vectors and local shear rates in arteries and opaque fluid flows by identifying and tracking flow tracers (ultrasound contrast microbubbles) within these flow fields. To improve the measurement accuracy, sub-pixel calculation method was adopted in this paper to maximize the ultrasound RF signal and B mode image correlation accuracy and increase the image spatial resolution. This algorithm is employed in processing both computer-generated particle image patterns and the B-mode images of microbubbles in rotating flows obtained by a high frame rate (up to 1000 frames per second) ultrasound imaging system. The results show the correlation of particle patterns and individual flow vector quality are improved and the overall flow mappings are also improved significantly. This would help the Echo PIV system to provide better multi-component velocity accuracy.
许多心血管问题的发展已被证明与动脉血流状况密切相关。最近开发了一种基于超声的粒子图像测速技术（回声粒子图像测速技术，Echo PIV），通过识别和跟踪这些流场中的流动示踪剂（超声造影微泡）来测量动脉和不透明流体流动中的多分量速度矢量和局部剪切率。为了提高测量精度，本文采用亚像素计算方法，以最大化超声射频信号和B模式图像的相关精度，并提高图像空间分辨率。该算法用于处理计算机生成的粒子图像模式以及由高帧率（高达每秒1000帧）超声成像系统获得的旋转流中微泡的B模式图像。结果表明，粒子模式的相关性和单个流动矢量质量得到改善，整体流动映射也得到显著改善。这将有助于回声粒子图像测速技术系统提供更好的多分量速度精度。
