【Tang Medical Science】Precautions for Ultrasound Examination

The main purpose of physical examination is to enable people to discover potential diseases in the body without subjective symptoms, so as to achieve the purpose of early detection, early diagnosis and early treatment. With the improvement of people's living standards and the development of medical technology, people's health awareness has been significantly improved, and regular physical examinations have become the choice of the majority of residents. Ultrasound has become an indispensable examination in health examinations because of its non-invasive, safe, fast, low-cost and high repeatability. So what should we pay attention to when doing ultrasound examinations?

Which organs require fasting for ultrasound examination and why?

Liver, gallbladder, pancreas, spleen, adrenal glands, abdominal cavity and retroperitoneal blood vessels, such as abdominal aorta, renal artery, iliac artery, inferior vena cava, etc., usually require fasting for more than 8 hours, and a light dinner is required the day before the examination. This is due to the inherent acoustic characteristics of ultrasound. Eating can cause increased intestinal gas, and gastrointestinal gas and contents will interfere with the display of the organs behind it, affecting the examination effect.

In addition, because the size of the gallbladder and the thickness of the gallbladder wall can change with meals, when a person fasts for 8 hours, the stomach contents are completely emptied and the gallbladder is filled with bile, which can accurately and clearly show the structure of the gallbladder and bile duct. If you eat before the examination, especially after a high-fat meal, the gallbladder will shrink, the gallbladder cavity will become smaller, and the gallbladder wall will thicken. It is difficult for ultrasound to distinguish whether the gallbladder is physiological or pathological, and it cannot clearly and accurately show the lesions of the gallbladder wall and gallbladder cavity.

Which organs require holding urine during ultrasound examination and why?

It is necessary to hold urine for transabdominal gynecology, urinary system (especially those who need to examine the bladder and lower ureter), prostate, seminal vesicle, etc. This is because these organs are in the deep pelvic cavity, surrounded by the intestines, and the contents and gas in the intestines will interfere with the ultrasound image. If you don't hold urine, the exploration will be "white" and nothing can be identified. After holding urine, the bladder fills up, thereby pushing the intestines away and avoiding the interference of intestinal gas; in addition, using the full bladder as a sound-transmitting window, the uterus, ovaries and other organs behind the bladder can be clearly displayed, which is conducive to diagnosis.
It should be noted that you should hold your urine moderately when doing the above organ examinations. If you hold your urine too much, the bladder will push and compress other organs, causing deformation and displacement of the organs, thus creating some false impressions and affecting the diagnosis.
For those who are unwilling to hold their urine, have difficulty holding their urine, or are elderly and weak and cannot hold their urine, but must undergo gynecological or prostate examinations, intracavitary (transvaginal/transrectal) ultrasound can be selected. In addition, the examinee should wear loose clothes before the physical examination, because it may be necessary to undress for the physical examination. Women should pay attention to not wearing dresses, pantyhose, long boots and other clothes that are not easy to put on and take off; when examining the carotid artery and thyroid, the neck needs to be fully exposed, so it is best to wear a low-necked top and do not wear necklaces or other accessories around the neck, otherwise it will affect the examination.

About the Author

Ultrasound Department Liu Chunxiang

Chief physician , director of the Ultrasound Department of Beijing Xiaotangshan Hospital, has been engaged in ultrasound medicine for many years and is good at ultrasound diagnosis of the abdomen, blood vessels, heart, superficial organs and other parts.