CAJ | 학술논문

基于平面波的超声成像方法可实现超快速的帧频，有利于检测人体组织中快速变化的信号，已成为超声领域研究的热点之一。采用多角度平面波相干复合的方法可有效抑制旁瓣，改善单一平面波的成像质量，权衡帧频和信噪比，可将其应用于血流的功率多普勒成像中。实验证明发射十个以上不同角度的平面波进行相干复合波束形成，B超图像对比度约为40 dB，且帧频可达1000 Hz。利用该方法在低速血流模型中进行实验，可以有效滤除组织信号，提取血流信号，信号强度表征血容量等血液动力学参数，说明基于平面波的功率多普勒方法对低速血流的检测具有较高的敏感性。在此基础上，深入探讨了复合图像采样帧数、时间分辨率和多普勒信息的关系。选取不同数量的复合图像计算血流功率多普勒信号，其帧频大于传统功率多普勒成像方法，可达百赫兹。复合图像帧数增多，帧频和时间分辨率降低，多普勒信息增强；反之亦然。高时间分辨率有利于快速血流检测，而提高灵敏度有利于微细低速血流检测。因此，基于平面波的功率多普勒成像技术有可能为心血管疾病和脑部血流检测开辟一条新思路。
기우평면파적초성성상방법가실현초쾌속적정빈，유리우검측인체조직중쾌속변화적신호，이성위초성영역연구적열점지일。채용다각도평면파상간복합적방법가유효억제방판，개선단일평면파적성상질량，권형정빈화신조비，가장기응용우혈류적공솔다보륵성상중。실험증명발사십개이상불동각도적평면파진행상간복합파속형성，B초도상대비도약위40 dB，차정빈가체1000 Hz。이용해방법재저속혈류모형중진행실험，가이유효려제조직신호，제취혈류신호，신호강도표정혈용량등혈액동역학삼수，설명기우평면파적공솔다보륵방법대저속혈류적검측구유교고적민감성。재차기출상，심입탐토료복합도상채양정수、시간분변솔화다보륵신식적관계。선취불동수량적복합도상계산혈류공솔다보륵신호，기정빈대우전통공솔다보륵성상방법，가체백혁자。복합도상정수증다，정빈화시간분변솔강저，다보륵신식증강；반지역연。고시간분변솔유리우쾌속혈류검측，이제고령민도유리우미세저속혈류검측。인차，기우평면파적공솔다보륵성상기술유가능위심혈관질병화뇌부혈류검측개벽일조신사로。
Emitting plane wave makes ultrasonic imaging enough fast so that it could detect variable blood signal in body, hence it becomes one of the most popular research interest. A new algorithm, multi-angle plane wave coherent compound imaging (MPWCCI) was realized to suppress side-lobe signal, improving the quality of ultrasonic image. Trading off frame rate and signal-noise-ratio (SNR), it could be used to image blood Power Doppler (PD). The contrast of B mode image could be up to 40 dB, and the frame rate to 1000Hz, using more than ten plane waves to compound. Test was accomplished in the slow-lfow blood phantom, it shows that clutter signal could be eliminated and blood signal could be extracted effectively, and ifnally an image depicting hemodynamics was obtained. Result veriifes that MPWCCI-PD has a ifne sensitivity to slow lfow. Furthermore, the effect of the ensemble size on image quality and temporal resolution was discussed. Calculating blood PDs in varying ensemble size data reveals that its frame rate exceeds that of conventional PD imaging, up to tens of Hertz, and the shorter the ensemble images are, the higher the temporal resolution and the better image, and vice versa. Higher temporal resolution is conducive to detecting fast blood lfow and better sensitivity is good for the detection of small vessels. MPWCCI-PD may be helpful to imaging cases caused by angiocardiopathy, or brain small vessels.