【作者】 丁康；

【导师】 曹铁生；

【作者基本信息】 第四军医大学 ， 影像医学与核医学， 2004， 博士

【摘要】 1．模拟实验研究心脏运动对多普勒血流频谱的影响 1．1 实验目的 通过自行设计和制作心底运动模拟仪，建立体外模拟实验模型，观察模拟心脏运动对模拟心底部血流多普勒频谱速度时间积分(Velocity-time integral，VTI)的影响。 1．2 实验方法 1．2．1 实验设备制作 实验一：用自制的、可产生模拟心底部运动的仪器——TD-3型心底运动模拟仪以及由管道支架、管道系统(内径为5mm的医用硅胶管)和蠕动泵组成的血流模拟器构成模拟实验装置的主体。模拟仪带动模拟心脏可以模拟人体心底部作竖直方向的往复运动；蠕动泵可以保证模拟血管内的血流成脉动性，满足实验中模拟人体心腔内瓣口血流频谱频率和幅度的要求。用6％的淀粉甘油水悬液作为模拟血液，以模拟人体血液红细胞浓度及血液的黏滞性。本实验中超声探头固定不动。 实验二：超声探头与心底运动模拟仪的滑动板连接，使探头与模拟心脏成为一体(transducer and stimulated heart，TSH)，同步运动，以模拟人体血流动力学实验中探头和心底部同步运动的实验过程。第四军医大学博士学位论文1.2.2指标观侧 实验一:用Sequoia 512超声心动图仪观察并记录心底运动模拟仪和血流模拟器两者在不同速度状态下分别运动、非同步和同步运动时，模拟血流多普勒流速曲线的特点;观察模拟心脏运动对模拟血流流速曲线VTI测定的影响及后者与模拟心脏运动频谱vTI间的定量关系。 实验二:观察并记录探头+模拟心脏与模拟血流同步或非同步运动时，模拟血流多普勒流速曲线的特点。1.3结果 实验一:当模拟心腔静止、其内模拟血流单独运动时，脉冲多普勒血流流速曲线表现为单方向的、速度相同的脉动液流。单独心腔运动的脉冲多普勒速度曲线表现为正弦波样机械运动。模拟心腔和其内模拟血流同步运动时，在模拟心脏运动作用下，模拟血流改变了原有的流速曲线波形:两者同向运动时，模拟血流流速曲线VTI为两者单独运动时的VTI之和，反向运动时为两者单独运动的VTI之差，而其中模拟心腔运动所产生的多普勒频移信号的速度和频率没有变化。 实验二:探头十模拟心脏与模拟心腔内的模拟血流同时运动时，不论探头十模拟心脏如何运动，模拟心腔内血流多普勒流速曲线的形态、Vmax和VTI与模拟血流单独运动时相同。这说明，只要探头与模拟血流之间没有相对运动，探头就可以记录到模拟血流相对于管壁的真实速度频谱。1.4结论a.心脏运动对模拟血流频谱的形态及其VTI均产生了影响，多普勒超声仪器所记录到的模拟血流的多普勒流速曲线，是经过模拟心脏运动按速度时间积分相加或相减规律调制了的、包含了两种运动成分的复合波。b.模拟心脏运动流速曲线vTI占模拟血流流速曲线vTI的‘25%，第四军医大学博士学位论文模拟心脏运动对模拟血流流速曲线VTI测值有明显影响。提示:在用多普勒方法测量血流量时应当考虑到心脏运动对多普勒测值的影响并加以矫正。2.心脏运动对人心脏瓣口多普勒血流频谱润定形响的实验研究2.1研究目的 观察在人体血流动力学实验中，探头与心底部同步运动时主动脉瓣口血流VTI的变化以及这些变化与常规该指标测定方法测值间的定量关系，为临床多普勒法测量每搏量的校正提供实验依据。2.2研究方法2.2.1实验设备制作 改制TD一3型心底运动模拟仪，将探头固定于心底运动模拟仪的可调运动板上，使探头与模拟心脏成为一体同步运动，并使可调运动板与探头的运动方向平行，制成TD一4型心底运动模拟仪。调整探头方向，使声束与左室流出道血流方向一致。2.2.2指标观测 对象为58位健康成人自愿者。在心尖五腔心切面，M型超声心动图记录主动脉瓣环机械运动曲线，测量心底部平均运动速度(即斜率cm/s)、幅度;脉冲多普勒记录主动脉瓣口vmax及vTI:计算人体心脏运动的VTI占相应瓣口血流频谱VTI的比例，同步描记ECG。对8位自愿进行在体模拟实验者，启动TD一4型心底运动模拟仪，以ECG的R波顶端为模拟仪运动触发点，使探头与受检者的心底部同步(指时间和幅度相同)或非同步(指时间不同、幅度相同)运动时，记录M型曲线及多普勒血流流速曲线的变化。2.3结果 收缩期心底部朝向探头运动，TD一4型心底运动模拟仪带动探头随着心脏做同步、同振幅的运动，M型曲线的收缩期朝向心尖部运动的波型消失，表现为一直线。模拟仪运动前，主动脉瓣口第四军医大学博士学位论文血流频谱中，心脏运动性多普勒频移信号S波的速度和VTI分别为16.3士2.7cm/s，3.83士0.83cm:血流频谱的速度和vTI分别为92.7士13.Zem/s，22.8士3.oem;人体心脏运动的vTI占相应瓣口血流vTI的16.8%士3.4%。当探头和心脏同步、同振幅运动时，s波消失，频谱的速度和VTI均较模拟仪运动前增大，分别为107.3士2.7em/s，24.6土2.sem。2.4结论a.收缩期主动脉瓣环的运动方向和主动脉瓣口血流方向相反，人体心脏运动的VTI占相应瓣口血流VTI的16.8%士3.4%。b.探头运动时记录的主动脉瓣口血流频谱VTI(即相当于不受心脏运动影响的真正的主动脉瓣口血流VTI)恰好是探头未更多还原

【Abstract】 1. The influence of cardiac motion on the velocity-time integrals of Doppler flow spectrum: in vitro model study1.1 ObjectiveTo design and make cardiac base motion simulated instrument by ourselves , and to establish simulated experimental model to observe the influence of simulated cardiac motion on the measurements of Doppler spectrum velocity- time integral (VTI) of simulated blood flow at the cardiac base.1.2 Methods1. 2.1 The fabrication of experimental instrumentTest I We simulated cardiac base motion by using Heart-Motion Simulator Model TD-3 (HMSTD-3) made by ourselves and blood flow simulator which was composed of pipeline plank, tubing and pulsatile pump. The pulsatile pump could make the simulated blood flow through the chamber to be of pulsatile so that it could satisfy the demand offrequence and amplitude of simulated blood flow in vitro. 6% starch-Glycer in water slurry was driven by the pulsatile pump through the tubing to simulate the blood flow in the simulated heart, and the tubing was cyclically moved by HMSTD-3. The transducer was stationary.Test II The echotransducer was fixed on the slide board of HMSTD-3 so that the transducer and the simulated heart became one part(transducer + simulated heart) and moved together. 1. 2. 2 Index observationTest I Acuson’ s Sequoia 512 and Acuson 128 XP/10ultrasonographic systems were used in this study to record the Doppler spectrum of simulated heart and simulated blood flow that moved separately , synchronously or unsynchronously, and to quantitatively assess their relations and the influence of simulated heart motion on the determation of Doppler spectrum VTI of the simulated blood flow.Test II To observe and note the feature of Dopplerspectrum of simulated blood flow when the transducer + simulated heart and simulated blood flow moved synchronously or unsynchronously respectively . 1.3 ResultsTest I In the model in vitro, the alterations in the motion of the tubing resulted in apparent changes in the measured maximal velocity and VTI of the fluid. The Doppler spectrum of the combined motion of the tubing and the fluidwas the algebraic sum of their Doppler signals. The velocity and frequency of Doppler spectrum generated by simulated heart motion did not change.Test II When transducer + simulated heart and simulated blood flow moved together, the shape, Vmax and VTI were the same as those when simulated blood flow moved along whether their motions were in phase or not. 1.4 ConclusionsThe motion of the simulated heart has a great influence on the form and the value of simulated Doppler blood flow spectrum VTI. The Doppler flow tracing which recorded by echocardiography was already modulated according to the VTI adding or subtracting by the simulated heart motion. The VTI of simulated heart accounted for 25% of the VTI of simulated Doppler blood flow spectrum and this effect should be considered when blood flow volume is measured by using Doppler’ s methods.2. Influence of cardiac motion on the measurement of Doppler flow spectrum through the valve: in vivo model study 2.1 ObjectiveTo quantitatively observe the changes of blood flow VTI through the aortic valve with the transducer moving in the same direction with the motion of cardiac base, and so as to help the correction of the way of measuring the stroke volume by Doppler methods. 2. 2 Methods 2. 2.1 The fabrication of experiment instrumentTo change the HMSTD -3 mode simulator into the HMSTD-4 mode cardiac base motion simulator model in vitro by fixing the transducer on the sliding board of the HMSTD -3 and to make the direction of sonar beam parallel to the direction of blood flow of left ventricular outflow tract. The frequency and amplitude of HMSTD-4 mode simulator were the same as those of the human subjects’ cardiac base motion. HMSTD-4 simulator was used to move the transducer with a water-balloon so that the transducer is relative stable to the sample volume at the aortic annulus when aortic Doppler flow at apex-five chamber view was recorded in su更多还原