Zhang Jiabin, Li Nan, Dong Feihong, Liang Shuyuan, Wang Di, An Jian, Long Yunfei, Wang Yuexiang, Luo Yukun, Zhang Jue
Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.
Institute of Molecular Medicine, Peking University, Beijing, China.
J Ultrasound Med. 2020 Aug;39(8):1507-1516. doi: 10.1002/jum.15238. Epub 2020 Feb 17.
Super-resolution ultrasound (SRUS) has become a tool for in vivo microvascular imaging. Most of the SRUS methods are based on microbubble localization: namely, ultrasound localization microscopy (ULM). The aim of this study was to develop a nonlocalization SRUS method and verify its feasibility in microvascular imaging.
We introduce a new super-resolution strategy based on the postprocessing of contrast-enhanced ultrasound. The proposed method, which is termed ultrasound diffraction attenuation microscopy (UDAM), uses super-resolution radial fluctuations instead of microbubble localization to overcome acoustic diffraction limits. Biceps of Japanese long-ear white rabbits were adopted to validate its feasibility on muscle vascular imaging, using a clinical accessible ultrasound system at a frame rate of 30 Hz under a single bolus injection of SonoVue (Bracco SpA, Milan, Italy). The super-resolution image was compared with the maximum-intensity projection and ULM.
The animal study illustrates that the proposed UDAM can obtain super-resolution microvascular images of rabbits' muscles under a single bolus injection of SonoVue with a 150-second contrast-enhanced ultrasound video. Both ULM and UDAM can achieve a very similar vascular structure with the maximum-intensity projection but much higher spatial resolution. The measurement of 1-dimensional signals shows that UDAM can distinguish the subwavelength structures and substantial reduce the full width at half-maximum of microvessels.
We conclude UDAM provides a noninvasive tool for in vivo super-resolution microvascular imaging.
超分辨率超声（SRUS）已成为一种用于体内微血管成像的工具。大多数SRUS方法基于微泡定位，即超声定位显微镜（ULM）。本研究的目的是开发一种非定位SRUS方法，并验证其在微血管成像中的可行性。
我们引入了一种基于超声造影后处理的新超分辨率策略。所提出的方法称为超声衍射衰减显微镜（UDAM），它使用超分辨率径向波动而非微泡定位来克服声衍射极限。采用日本长耳白兔的二头肌，在单次团注声诺维（意大利米兰的Bracco SpA公司）的情况下，使用临床可用的超声系统以30 Hz的帧率来验证其在肌肉血管成像中的可行性。将超分辨率图像与最大强度投影和ULM进行比较。
动物研究表明，所提出的UDAM在单次团注声诺维并采集150秒的超声造影视频的情况下，能够获得兔肌肉的超分辨率微血管图像。ULM和UDAM与最大强度投影相比，都能实现非常相似的血管结构，但空间分辨率要高得多。一维信号测量表明，UDAM能够区分亚波长结构，并大幅降低微血管的半高宽。
我们得出结论，UDAM为体内超分辨率微血管成像提供了一种非侵入性工具。
