At present, ultrasound examination has become a routine item for clinical disease examination and health checkup because of its simplicity, non-invasive, non-radiological damage, low price and repeatability. However, in practice, it is often found that ultrasound examinations cannot be completed successfully because patients and some clinical staff do not know much about the preparation work before ultrasound examination. In order to better diagnose diseases, improve the accuracy of ultrasound examination, avoid the interference of other factors, and reduce the occurrence of misdiagnosis and leakage, special preparation is needed before ultrasound examination of certain parts. Ultrasound examination of liver, gallbladder and pancreas Ultrasound examination of liver, gallbladder and pancreas should be performed in the morning with 8-12 hours of fasting and fasting, such as after barium meal examination, after the discharge of barium. (1) Since the gallbladder is a cavity organ, it has the function of bile storage and concentration. Under the condition of no bile filling, the gallbladder wall will be thickened and the gallbladder cavity will not be displayed, which will easily lead to leakage and misdiagnosis of gallbladder-related diseases. Therefore, gallbladder examination should be performed after 8-12 hours of abstinence from drinking and fasting to fill the gallbladder with bile and increase the ultrasound image of the gallbladder cavity to reduce the misdiagnosis and leakage of gallbladder infection, gallbladder stones, gallbladder polyps and other diseases. (2) The pancreas is located in the retroperitoneal organ and is obscured by the gastrointestinal tract and other organs in front of it. After eating and drinking and after a period of morning activity, gas tends to accumulate in the gastrointestinal tract, interfering with the penetration of ultrasound sound waves, causing the pancreas not to be visualized and easily causing pancreatic diseases to be missed and misdiagnosed. Therefore, in order to reduce misdiagnosis and leakage of liver, biliary and pancreatic diseases, routine ultrasound examinations of liver, biliary and pancreatic glands are usually scheduled in the morning on an empty stomach. However, except for acute abdomen and acute trauma where organ damage should be excluded. 2. Ultrasound examination of the beginning segment of the renal artery, abdominal aorta, iliac vessels and mesenteric lymph nodes Because the above examination is easily disturbed by the gas in the gastrointestinal tract in front, the above examination should be done on an empty stomach and in the morning. 3, bladder, prostate examination The bladder is a cavity organ, in order to better display the bladder cavity and bladder wall, the bladder needs to be fully held, after the bladder is full, so that the bladder cavity and wall display more clearly, to facilitate the diagnosis of bladder disease. The prostate is located under the bladder neck opening. The uterus is located behind the bladder, and the unfilled bladder tends to block the ultrasound sound waves during transabdominal ultrasonography, resulting in poor imaging of the uterus and both adnexa. For better visualization of the uterus and both adnexa, it is necessary to fully fill the bladder. 5, maternal ultrasound examination before 12 weeks of pregnancy maternal ultrasound examination, so the amount of amniotic fluid is not much, you need to fill the bladder in an appropriate amount. In addition, it is also necessary to fill the bladder in an appropriate amount when it is necessary to exclude conditions such as placenta praevia. 6, infant and child ultrasound examination Because infants and children are prone to crying, resulting in unstable ultrasound probe, easy to slide, unclear ultrasound images, unable to make a diagnosis. Therefore, it is best to examine infants and children when they are asleep or after asking the pediatrician to give a sedative.