Ultrasound examination precautions 1, abdominal ultrasound examination should be performed in the morning on an empty stomach as far as possible, including the liver, gallbladder, pancreas, bile ducts, retroperitoneum, large abdominal vessels, etc., fasting after 9:00 pm before the examination (must fast for more than 8 hours), and no drinking after 12:00 pm. 2, abdominal ultrasound should be arranged before endoscopy (gastroscopy), barium meal and cholangiography. Cardiac ultrasound should be examined before 24-hour ambulatory electrocardiogram and ambulatory blood pressure. Emergency ultrasonography (e.g. trauma, suspected biliary stone impaction, etc.) is not subject to the above conditions. 3. Bladder, prostate, seminal vesicle, ureteral stones, gynecological and early pregnancy ultrasound (before 13 weeks, i.e. within 3 months of pregnancy) should be performed after holding urine. Patients should drink 500~1000ml of water 1~2 hours before the examination. 4. Transrectal examination of the prostate and seminal vesicles should be preceded by defecation and moderate urine holding. The urine should be emptied before transvaginal ultrasound examination, and it is advisable to examine after menstruation to avoid infection. 5.Usually, no special preparation is needed for the examination of fetus, kidney, spleen, eye, thyroid, breast, blood vessels of the limbs and adult heart in the middle and late pregnancy. 6. In the absence of special circumstances (coma, severe trauma, etc.), patients are advised to wear loose clothing to the clinic. Do not wear necklaces and other ornaments for neck ultrasound examinations (including thyroid, neck vessels, etc.). 7.If infant patients do not cooperate, they can be examined after taking sedative drugs under the guidance of clinicians. 8.Some examinations may require special preparations due to different conditions of patients, and the ultrasonographer will provide specific instructions when needed. 9.Bring your previous ultrasound checklist to the clinic so that we can help you make comparisons.