Kremkau F W
Clin Diagn Ultrasound. 1992;27:7-60.
DCI acquires Doppler-shifted echoes from a cross-section of tissue scanned by an ultrasound beam. These echoes are then presented in color and superimposed on the gray-scale anatomic image of non-Doppler-shifted echoes received during the scan. The flow echoes are assigned colors according to the color map chosen. Usually red, yellow, or white indicates positive Doppler shifts (approaching flow) and blue, cyan, or white indicates negative shifts (receding flow). Green is added to indicate variance (disturbed or turbulent flow). Several pulses (the number is called the ensemble length) are needed to generate a color scan line. Linear, convex, phased, and annular arrays are used to acquire the gray-scale and color-flow information. Doppler color-flow instruments are pulsed-Doppler instruments and are subject to the same limitations, such as Doppler angle dependence and aliasing, as other Doppler instruments. Color controls include gain, TGC, map selection, variance on/off, persistence, ensemble length, color/gray priority. Nyquist limit (PRF), baseline shift, wall filter, and color window angle, location, and size. Doppler color-flow instruments generally have output intensities intermediate between those of gray-scale imaging and pulsed-Doppler duplex instruments. Although there is no known risk with the use of color-flow instruments, prudent practice dictates that they be used for medical indications and with the minimum exposure time and instrument output required to obtain the needed diagnostic information.
DCI从超声束扫描的组织横截面获取多普勒频移回波。然后，这些回波以彩色呈现，并叠加在扫描期间接收到的非多普勒频移回波的灰度解剖图像上。根据所选的颜色图为血流回波分配颜色。通常，红色、黄色或白色表示正多普勒频移（血流靠近），蓝色、青色或白色表示负频移（血流远离）。添加绿色表示方差（紊乱或湍流）。生成一条彩色扫描线需要几个脉冲（脉冲数量称为总体长度）。线性、凸面、相控阵和环形阵列用于获取灰度和彩色血流信息。多普勒彩色血流仪是脉冲多普勒仪器，与其他多普勒仪器一样，存在相同的局限性，如多普勒角度依赖性和混叠。彩色控制包括增益、TGC、图选择、方差开/关、持久性、总体长度、彩色/灰度优先级。奈奎斯特极限（PRF）、基线偏移、壁滤波器以及彩色窗口角度、位置和大小。多普勒彩色血流仪的输出强度通常介于灰度成像和脉冲多普勒双功能仪器之间。虽然使用彩色血流仪尚无已知风险，但谨慎的做法是，仅在有医学指征时使用，并在获得所需诊断信息所需的最短暴露时间和仪器输出条件下使用。
