Improved Super-Resolution Ultrasound Microvessel Imaging With Spatiotemporal Nonlocal Means Filtering and Bipartite Graph-Based Microbubble Tracking.
Improved Super-Resolution Ultrasound Microvessel Imaging With Spatiotemporal Nonlocal Means Filtering and Bipartite Graph-Based Microbubble Tracking.
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DOI：
10.1109/tuffc.2017.2778941
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发表时间：
2018-03
期刊：
影响因子：
--
通讯作者：
Chen S
中科院分区：
文献类型：
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作者：
Song P;Trzasko JD;Manduca A;Huang R;Kadirvel R;Kallmes DF;Chen S
近年来，多项研究提出了利用造影剂微泡进行超分辨率超声微血管成像，显示出出色的分辨率，具有很高的临床应用潜力。本研究旨在利用超快平面波成像技术解决人体体内超分辨率成像中潜在的噪声问题。超快成像所提供的丰富的时空信息使微泡信号能够从背景噪声中分离出来。此外，微泡数据的高帧率记录使得在粒子跟踪测速中常用的鲁棒跟踪算法得以实现。在本研究中，我们在微泡数据的时空域上应用非局部均值（NLM）去噪滤波器，以保留微泡运动引起的微泡轨迹，并抑制随机背景噪声。然后，我们实现了一种基于二部图的配对方法，并使用持久性控制来进一步提高微泡信号质量和微泡跟踪保真度。在兔体内肾灌注研究中，NLM滤波器显示出有效的噪声抑制和显著改善的微泡定位。二部图配对和持久性控制进一步降低了噪声，改善了微血管描绘和更一致的微血管血流速度测量。利用所提出的方法和对自由呼吸的家兔进行徒手扫描，可以在约2 cm深度（超声发射中心频率= 8 MHz，理论空间分辨率~200 μm）下成像全宽为57 μm的单个微血管横截面。距76 μm的皮质微血管也能明显分离。这些结果表明，所提出的方法在促进体内临床超分辨率微血管成像方面具有良好的潜力。
Super-resolution ultrasound microvessel imaging with contrast microbubbles has recently been proposed by multiple studies, demonstrating outstanding resolution with high potential for clinical applications. This study aims at addressing the potential noise issue in in vivo human super-resolution imaging with ultrafast plane wave imaging. The rich spatiotemporal information provided by ultrafast imaging presents features that allow microbubble signals to be separated from background noise. In addition, the high frame rate recording of microbubble data enables the implementation of robust tracking algorithms commonly used in particle tracking velocimetry. In this study, we applied the nonlocal means (NLM) denoising filter on the spatiotemporal domain of the microbubble data to preserve the microbubble tracks caused by microbubble movement and suppress random background noise. We then implemented a bipartite graph-based pairing method with the use of persistence control to further improve the microbubble signal quality and microbubble tracking fidelity. In an in vivo rabbit kidney perfusion study, the NLM filter showed effective noise rejection and substantially improved microbubble localization. The bipartite graph pairing and persistence control demonstrated further noise reduction, improved microvessel delineation and a more consistent microvessel blood flow speed measurement. With the proposed methods and freehand scanning on a free-breathing rabbit, a single microvessel cross-section profile with full width at half maximum of 57 μm could be imaged at approximately 2 cm depth (ultrasound transmit center frequency = 8 MHz, theoretical spatial resolution ~200 μm). Cortical microvessels that are 76 μm apart can also be clearly separated. These results suggest that the proposed methods have good potential in facilitating robust in vivo clinical super-resolution microvessel imaging.