1.Why should we fast or hold urine before the examination? Why did the doctor order to fast or hold urine before the ultrasound examination? Of course, it is to get the best ultrasound examination results. So, in which cases do we need to fast or hold urine? The gastrointestinal tract often contains a lot of gas, and people can send a lot of gas into the gastrointestinal tract with swallowing food when they eat, and some foods can also produce more gas during digestion, such as milk and beans. These gases can interfere with the passage of ultrasound and affect the clarity of the image, which can easily cause misdiagnosis or missed diagnosis. Therefore, it is best to fast when examining the pancreas, liver, abdominal aorta and inferior vena cava. The physiological function of the gallbladder is to store bile. Under normal circumstances, the gallbladder will contract after a person eats fatty foods and expel bile. When the bile in the gallbladder is reduced, it is not easy to see the lesions on the wall of the gallbladder clearly during ultrasound examination. Therefore, doctors often instruct patients to eat light, low-fat, non-gas-producing foods for dinner the day before the abdominal ultrasound examination, with the aim of minimizing gas in the gastrointestinal tract while allowing the gallbladder to fully fill to minimize interfering factors to obtain the best images to improve the confirmation rate. [Examination of the bladder, pelvic masses, transabdominal examination of the uterus, ovaries, prostate, etc.] Holding the urine to fill the bladder can make the bladder wall show more clearly; moreover, because the uterus, ovaries, prostate and other organs are located in the lower, deeper position of the pelvic cavity below the back of the bladder, the front and top of which are covered by a large number of intestinal tubes, it is difficult for ultrasound to penetrate the intestinal gas to reach these organs. The urine-filled bladder can effectively push away the intestinal tubes occupying the pelvic cavity, overcoming the interference of intestinal gas and elevating the position of these organs so that they are clearly visible. When it is necessary to observe the length of the cervical canal or the position of the lower edge of the placenta, it is also necessary to hold urine moderately (with a clear urge to urinate). It is important to note that we should not perform ultrasound reluctantly when we are not well prepared as mentioned above. If we are not well prepared as required, the images of the organs are not clear, which may cause misdiagnosis and leakage, and we may not get timely and correct diagnosis, and we have to repeat the ultrasound examination or do more expensive examinations such as CT or MRI next time, which delays the treatment of diseases. In a word, it costs money and effort. 2.Who is the most capable of holding urine? Ultrasound basics have said that when the ultrasound doctor trick is to drink less water and be able to hold urine! The key is good kidney, everyone is good! Ultrasound doctors are busy from morning to night, examining patients one after another, want to give each patient a more careful examination, but the queue of patients is too much, someone in the middle can not care about drinking water (no time to pour), someone can not even care about lunch and lunch break, often there is no time to go to the toilet. When you find yourself unable to hold your urine, maybe the sonographer is holding it too!