Ultrasound diagnostic techniques and CT have their own advantages and disadvantages: First, ultrasound scanning can observe the movement and function of organs in a coherent and dynamic manner; it can track lesions and show three-dimensional changes without the limitation of its imaging stratification. Ultrasonography is now recognized as the preferred method of examination for biliary system diseases. Secondly, ultrasound can monitor blood flow and direction of organs other than substantive organs (liver, pancreas, spleen, kidney, etc.) in combination with Doppler technology to identify the nature and extent of organ damage. For example, through cardiac ultrasound, doctors can visually see various structures in the heart and whether there are abnormalities. Third, ultrasound equipment is easy to move and non-invasive, so patients with mobility problems can be diagnosed at the bedside. Fourth, the price is low. The cost of ultrasound examination is generally 140-150 yuan per time, which is 1/3 of CT examination and 1/5 of MRI, which is more affordable for most working class people. “Ultrasound” is therefore often used for health checkups. Fifth, ultrasound has no radiation to the human body, so it can be used in priority for special patients. The disadvantages of ultrasound diagnosis: Due to the different imaging principles, several instruments have their own outstanding characteristics for the examination of various organs. For example, ultrasound is significantly weaker than CT in terms of clarity and resolution. 2. Ultrasound is easy to miss lesions in the intestinal tract and other cavity organs. 3.Gas has a great impact on ultrasound, and patients are susceptible to patient intestinal gas interference and other factors affecting the examination results. 4.Ultrasound examination needs to change the body position and hold the breath, etc. It is not suitable for patients with fracture and unable to cooperate. 5, the examination results are also vulnerable to the level of clinical skills of physicians. Myths of ultrasound: 1. The concept of “ultrasound room”? B-type ultrasound is only one of the current ultrasound diagnostic techniques, the current ultrasound diagnosis is a composite of B-type ultrasound, color ultrasound, Doppler ultrasound, three-dimensional ultrasound, interventional ultrasound and other ultrasound diagnostic techniques, the times are developing, the concept of people should also be updated. 2.Is ultrasound examination (“B-ultrasound”) harmful to human body? Ultrasound is a routine examination for patients in hospitals, and there have been no reports of damage to patients so far, and it is one of the six major diagnostic imaging devices in the medical field. 3.Can we see clearly by doing “ultrasound”? Imaging examination is only an auxiliary examination for clinical diagnosis, and imaging, that is, looking at the shadow guess, is not able to diagnose qualitatively. Its performance is high and low echogenic images, and clinicians need to combine the patient’s clinical performance and their own experience to make a diagnosis, any disease can not rely completely on “ultrasound” and sure.