The full name of color ultrasound is color Doppler flow imaging, abbreviated as CDFI in English, which is a new modern medical imaging technology produced and applied to clinical practice in the 1980s. It is a color flow map that uses the principle of ultrasound Doppler effect to display the Doppler blood flow signal according to the distribution state of blood flow velocity. Color ultrasound CDFI visible blood flow signal is a description of ultrasound examination results, and this description can be seen in the diagnosis of various heart diseases and vascular diseases, as well as the analysis of the blood perfusion volume of tissues and organs and internal organs, and the judgment of the nature of tumors. 1. for the examination of various heart diseases: the blood flow signal of color ultrasound can assist in the diagnosis of various congenital heart diseases, and can accurately determine the type of congenital heart disease, the It can accurately determine the type of congenital heart disease, the size of the lesion, the amount of fractional flow and estimate the pulmonary artery pressure, providing an important basis for surgery. 2. For blood vessels with an inner diameter of more than 1mm, the blood flow signal of color ultrasound can visually show the change of blood vessel wall and the change of blood flow, and it can be used to confirm the diagnosis of vasculitis, phlebitis and venous valve function; 3, analysis of blood perfusion of tissues, organs and internal organs: if you want to know whether the blood perfusion of an organ is normal, you can also use color ultrasound to complete this examination, for example, after kidney transplantation, the blood flow signal of color ultrasound can clearly show the blood vessels of the kidney. For example, after kidney transplantation, the blood flow signal can clearly show the renal vascular anastomosis, observe whether there is stenosis and thrombosis at the anastomosis site, and judge the effect of surgery; 4. Judgment of tumor nature: It has long been found in pathology that there are big differences between benign and malignant tumors in terms of blood supply and vascular growth. For example, liver cancer has more neovascularization and rich blood vessels in the tumor, so rich blood flow signal can be found in color ultrasound examination, while benign tumors are generally not rich in blood vessels, so blood flow signal in the tumor is less in color ultrasound examination. Based on this point, it is of great clinical value to determine the nature of tumor.