彩超基础知识简介

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                    <section><section powered-by="gulangu"><section><p><img src="image/20201019/7379b38dbe9c0944cb735d1f43298e74_1.gif" /></p></section></section><section powered-by="gulangu"><section><section><p>彩超</p></section><p><img src="image/20201019/ea69cd75ab8f71dc1e53dc9484211737_2.png" /></p> <section></section></section></section><section powered-by="gulangu"><section><section><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;彩超狭义上指彩色多普勒血流现象（CDFI），广义上包括有：彩色多普勒血流显像（CDFI）；彩色多普勒组织成像（CDTI）；经颅彩色多普勒血流成像（TCD）；彩色多普勒能量图（CDE）；频谱多普勒等。其基本原理是依赖于多普勒效应。</p><p>注：彩阶B超（CSBU），即伪彩，不是真正的彩超，多数学者认为这一名词容易引起误解而宜删去，但此词已广为流传，故暂予保留。</p></section></section></section><section powered-by="gulangu"><section><section><p>多普勒效应</p></section><p><img src="image/20201019/ea69cd75ab8f71dc1e53dc9484211737_2.png" /></p> <section></section></section></section><section powered-by="gulangu"><section><section><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 当一辆救护车向我们疾驶而来时，我们听到的蜂鸣声会比其常态行驶中的高，当救护车从我们身边驶过时，我们会感觉到它的蜂鸣音突然降低了。我们将这种现象称作多普勒效应。</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;此种声音变化是由于生源（救护车）与观察者（你）之间的相对运动速度而产生的。</p></section></section></section><section powered-by="gulangu"><section><section><p>人体多普勒效应</p></section><p><img src="image/20201019/ea69cd75ab8f71dc1e53dc9484211737_2.png" /></p> <section></section></section></section><section powered-by="gulangu"><section><section><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 多普勒效应是由于声波频率发生变化而产生的。在超声系统中，由探头产生并采集声波信号。红细胞游向探头时，声波的反射频率会高出其原始频率；而游离探头时，频率会降低。多普勒超声技术在医学领域中多用于对人体血流的探测和测量，其主要反射物为血红细胞。</p></section></section></section><section powered-by="gulangu"><section><p><img src="image/20201019/e55be6f34d25e22f48ddec998a59afac_5.jpg" /></p></section></section><section powered-by="gulangu"><section><section><p>彩色血流成像</p></section><p><img src="image/20201019/ea69cd75ab8f71dc1e53dc9484211737_2.png" /></p> <section></section></section></section><section powered-by="gulangu"><section><section><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;彩色血流成像（CFM）是在二维声像图上叠加彩色实时血流显像，每一个彩色的点表示小区域内血液流量的平均值。不同的颜色代表血液流量的速度及检测方式的不同，通常，红色表示迎向探头的血流方向，蓝色表示离向探头血流方向。</p></section></section></section><section powered-by="gulangu"><section><p><img src="image/20201019/591dac0a89eab7da36f9e4fc63a2cb54_7.jpg" /></p></section></section><section powered-by="gulangu"><section><p><img src="image/20201019/9f685462fb24162509d581258f18d22a_8.jpg" /></p></section></section><section powered-by="gulangu"><section><section><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;二维彩色多普勒的颜色所显示的是血流的基本特性。无血流运动时，便无颜色显示；红色代表血液流向探头，血流速度加快时，颜色会慢慢转变成黄色；蓝色代表血液流离探头。血流速度加快时，颜色会慢慢转变成天蓝色。</p></section></section></section><section powered-by="gulangu"><section><p><img src="image/20201019/2eb4c5e4b71a6def1662320e4e31692e_9.jpg" /></p></section></section><section powered-by="gulangu"><section><section><p>多普勒方程式</p></section><p><img src="image/20201019/ea69cd75ab8f71dc1e53dc9484211737_2.png" /></p> <section></section></section></section><section powered-by="gulangu"><section><section><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;多普勒效应是由于声源与接收者之间的运动而产生的声波频率变化，或者是由于反射体运动而使反射波发生变化。<br  /></p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 多普勒频移受声波频率、血流速度、声束与血流方向之间的角度等因素的影响，其间的关系如下列多普勒方程式所示。</p></section></section></section><section powered-by="gulangu"><section><p><img src="image/20201019/98335ff77b582b2d41b0e32b2038ec0b_11.jpg" /></p></section></section><section powered-by="gulangu"><section><section><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;从上面的公式中，我们可以看到，多普勒效应会因为cosθ值的不同而发生变化。</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 声波作用的角度始终保持在60°以下，因为60°以上时，cos函数的曲线很陡，因此，控制角度对于精确测定多普勒频移和血流流速十分重要。</p></section></section></section><section powered-by="gulangu"><section><p><img src="image/20201019/4d4b9ecd712dbd08029d9eb6e2c39d11_12.jpg" /></p></section></section><section powered-by="gulangu"><section><section><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; cos90°的值是0，则超声波与血流成直角，应不可能产生多普勒频移，系统也就无法检测到血管中实际存在的血流。</p></section></section></section><section powered-by="gulangu"><section><p><img src="image/20201019/58f13c99a004be2b11a6ded57633ab52_13.jpg" /></p></section></section><section powered-by="gulangu"><section><section><section powered-by="gulangu"><section><section><p>欢</p></section></section></section></section><section><section powered-by="gulangu"><section><section><p>迎</p></section></section></section></section><section><section powered-by="gulangu"><section><section><p>关</p></section></section></section></section><section><section powered-by="gulangu"><section><section><p>注</p></section></section></section></section></section></section><section powered-by="gulangu"><section><section><p><br  /></p></section></section></section><section powered-by="gulangu"><section><section><section powered-by="gulangu"><section><p><img src="image/20201019/d531d346033633cf8d619ce01740f58a_14.jpg" /></p></section></section></section><section><section powered-by="gulangu"><section><section></section></section></section></section><section><section powered-by="gulangu"><section><section><p>关注我们</p><p>一起涨姿势！</p></section></section></section></section></section></section></section>