无造影剂增强的超快超声脊髓微血管成像方法  

Non-contrast-enhanced ultrafast ultrasound Doppler imaging of spinal cord micro-vessels

作　　者：臧佳琦 许凯亮 韩清见 陆起涌[1] 梅永丰[3] 他得安 Zang Jia-Qi;Xu Kai-Liang;Han Qing-Jian;Lu Qi-Yong;Mei Yong-Feng;Ta De-An(Center for Biomedical Engineering,School of Information Science and Technology,Fudan University,Shanghai 200433,China;Institutes of Brain Science,Fudan University,Shanghai 200433,China;Department of Materials Science,Fudan University,Shanghai 200433,China;Shanghai Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention,Shanghai 200433,China)

机构地区：[1]复旦大学信息科学与工程学院,上海200433 [2]复旦大学脑科学研究院,上海200433 [3]复旦大学材料科学系,上海200433 [4]上海市医学图像处理与计算机辅助手术重点实验室,上海200433

出　　处：《物理学报》2021年第11期127-137,共11页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11974081,11827808,51961145108);上海市自然科学基金(批准号:19ZR1402700);上海市青年科技启明星计划(批准号:20QC1400200);上海市优秀学术带头人计划(批准号:19XD1400500)资助的课题。

摘　　要：微小血管及其血流实时成像对监测生物体血氧代谢等具有重要意义.在无微泡造影剂的情况下,传统超声多普勒技术仍较难实现高信噪比的微小血管成像.本研究提出了一种无造影剂增强的超快超声脊髓微血管成像方法.本研究从基于多角度复合平面波的高帧频成像技术出发,提出基于特征值分解的频率-幅值双阈值滤波法,从而将脊髓组织信号和微血流信号分离,可实现脊髓内微血流的动态成像.在体成像实验结果表明,无超声造影剂时,超快超声多普勒成像技术仍可获得较为清晰的大鼠脊髓内微血流的实时图像,并能够清晰地呈现脊髓受损所致的微血流缺失状况.定量分析结果表明,增大复合平面波角度数可有效提高图像的信噪比.综上,超快超声多普勒成像技术有潜力被应用于脊髓内微血管成像及功能实时监测与动态评价,相关结果可为脊髓功能成像方法的研究提供借鉴.With the advantages of non-radiation and low-cost,ultrasound imaging has been widely used in clinical diagnosis.However,due to the compromise between temporal and spatial resolution,the traditional ultrasound imaging method which collects images line by line fails to obtain the images at a high frame rate.Ultrafast ultrasound imaging method based on the plane-wave emission can achieve a high frame rate with the capability for instantaneous hemodynamic imaging of neurovascular response.Besides,by the coherent compounding of the echo signals received from emitting a set of tilting plane-waves,the image quality can be improved in terms of resolution,contrast and signal-to-noise ratio(SNR).Considering the fact that received signals are the mixture of echo signals from the low-speed soft tissue and high-speed blood flow,a clutter filtering method is used to remove the signals of soft tissue.In this study,the ultrafast ultrasound sequence of emission and reception is designed to image the spinal cord by using the groups of multiple steering-angle plane-waves.The so-called f-k migration algorithm based on an exploding reflector model(ERM)is used for coherent plane-wave compounding.Eigenvalue decomposition(EVD)is then applied to tissue and blood signal extraction.The static tissue signals correspond to eigenvectors with low Doppler frequency shift and large magnitude eigenvalue while the high-speed blood flow signals correspond to eigenvectors with high Doppler frequency shift and small eigenvalue.Therefore,frequency and amplitude thresholds can be applied to the accurate separation of the blood component and the tissue component.After the signal extraction,the hemodynamic imaging of blood vessels can thus be obtained from the power Doppler results.The experiments are carried out by using a programmable ultrasonic array system and a high-frequency linear array transducer L22-14 vX with a central frequency of 15.625 MHz.The sample acquisition frequency is set to be 62.5 MHz.In rat experiments in vivo,14040 angle-stilting

关 键 词：超快超声多普勒 杂波滤除 特征值分解 脊髓微血管 

分 类 号：R445.1[医药卫生—影像医学与核医学]