Ultrasound examination is easy to perform, non-invasive, non-radiation, and very widely used in clinical practice. To obtain satisfactory examination results, in addition to the physician’s operation and diagnosis, the preparation before ultrasound examination is also important, and sometimes even directly affects the accuracy of the examination results. The precautions before ultrasound examination are related to the examination site. 1, abdominal ultrasonography (liver, gallbladder, pancreas, spleen, retroperitoneal organs) To avoid interference with gastrointestinal tract contents and gas, abdominal ultrasonography should be performed on an empty stomach before the examination. The day before, you should eat less fatty food, especially dinner to avoid excessive meat, eggs, soy products, milk and other foods, and you should not eat again 8 hours before the examination. In case of patients with excessive abdominal gas or constipation, the doctor may ask the patient to take laxative medication before performing the examination, and the patient should cooperate carefully. If the patient has to undergo gastrointestinal or cholecystography at the same time, the ultrasound examination should be arranged before the above-mentioned examinations, or after three days of barium gastrointestinal meal and two days of cholecystography to avoid the interference of barium and gas. Patients with hypertension can take antihypertensive drugs on time on the day of the examination, with a small amount of plain water, and do not drink milk, soy milk or juice and other beverages. Diabetic patients can take a moderate amount of candy to relieve hunger on the day of the examination. Patients who need to undergo gallbladder systolic function test should bring two fried eggs to the examination room. The examination of peritoneal fluid or pleural fluid and body surface localization generally do not require special preparation such as fasting and can be performed at any time. 2.Urological system (kidney, ureter, bladder, prostate, etc.) and adrenal ultrasound examination simply examining the kidney and ureter do not require special preparation. However, when the physician suspects a urinary stone, especially a ureteral stone, the patient may need to fill the bladder before the examination. Bladder ultrasonography requires a full bladder. Male patients also require bladder filling for prostate and vesicoureteral gland examinations. Patients undergoing residual urine volume measurement will need to fill their bladder until they feel full and then empty their bladder after the sonographer has confirmed this. To ensure accurate measurement of residual urine volume, care should be taken not to repeatedly urinate multiple times and also to perform ultrasound measurements within 5 minutes of emptying the bladder. Residual urine volume measurement cannot be performed when a catheter is in place. No special preparation is usually required for adrenal ultrasound. Intra-abdominal gas may affect the examination results, so the day before the ultrasound examination, try to eat less gas-producing food, constipated patients can take appropriate laxative. 3, gynecological ultrasonography: transabdominal gynecological ultrasonography, the patient must keep the bladder full to achieve the examination effect. Therefore, you should stop urinating 2-3 hours before the examination and drink 500-1000ml of water at the same time, so that the examination can be performed only after the bladder is full and the urge to urinate is obvious. In case of excessive pelvic gas or constipation, the patient may be required to take laxative medication before the examination. In the case of transvaginal ultrasound, there is no need to fill the bladder and also try to empty the bladder before the examination. Transvaginal ultrasound is usually not performed during menstruation or in cases of acute pelvic inflammatory disease. Follicle monitoring and examination of certain endothelial lesions should be performed during specific periods of the menstrual cycle. Please make an appointment for the examination date according to the specific requirements of your doctor. 4.Ultrasound examination of various superficial organs such as thyroid, breast, parotid, submandibular gland, superficial lymph nodes, body surface masses, joints, etc. generally requires no special preparation, as the examination site can be fully exposed. Before the examination, it is best to remove all kinds of ornaments from the examination area and wear clothes that are easy to put on and take off (for example, do not wear necklaces or high-collared clothing for thyroid ultrasound). 5. Vascular ultrasound examination of the neck vessels: The neck should be exposed during the examination, so please do not wear necklaces or high-collared clothing. No other special preparation is required. Abdominal vascular examination: including abdominal aorta, abdominal trunk, superior and inferior mesenteric arteries, renal artery, iliac artery, inferior vena cava, hepatic vein, portal venous system, etc. The preparation before examination is the same as that of abdominal ultrasonography. Limb vascular examination: no special preparation is needed, but the corresponding limbs should be exposed during the examination, please wear clothes that are easy to put on and take off. 6.Ultrasound-guided interventional localization or treatment requires confirmation of the lesion by the ultrasound interventional doctor to determine the feasibility of interventional localization or treatment. Make preoperative preparations according to the requirements of the ultrasound interventional surgeon, complete various preoperative examinations and sign the informed consent form. Family members must accompany the patient on the day of interventional positioning or treatment. 7.Transrectal ultrasonography requires advance bowel preparation, taking laxatives and emptying the intestines before examination. 8.Ultrasound imaging: It is necessary to confirm the lesion by the ultrasonographer, prepare for the examination according to the ultrasonography examination site and the ultrasonographer’s requirements, and sign the informed consent form. Family members must accompany the patient on the day of ultrasonography examination. 9.Ultrasound examination for infants and children: If the cooperation with ultrasound examination is poor, sedation can be given in advance and the examination can be performed after they are asleep. Your good cooperation is an important prerequisite for the correct diagnosis of the disease.