In the past, ultrasound was used for screening and diagnosis of gastrointestinal diseases clinically, but there is a large amount of gas in the human gastrointestinal tract, which will affect the accuracy of ultrasound examination. Gastrointestinal contrast-enhanced ultrasonography came into being. It fills the gastrointestinal tract with oral or enema contrast agent, which solves the impact of gas in the gastrointestinal tract on ultrasound examination and improves the accuracy of diagnosis. At present, gastrointestinal contrast-enhanced ultrasonography has become an effective and widely used diagnostic tool for diagnosing gastrointestinal diseases. Below, the author will take you to understand this inspection and diagnostic technology by answering 5 questions.
1. What is the principle of gastrointestinal contrast-enhanced ultrasonography?
Gastrointestinal contrast-enhanced ultrasonography, also known as gastrointestinal filling examination, is a form of oral or enema contrast agent to fill the stomach and eliminate the interference of gas and contents in the gastrointestinal cavity on ultrasound, thus It is an ultrasound examination method that effectively improves the internal environment of gastrointestinal ultrasound imaging and clearly shows the hierarchical structure of the gastrointestinal wall and lesions.
The contrast agents used in the process of gastrointestinal ultrasonography examination can be divided into two types: anechoic water dosage form and echogenic powder dosage form. Among them, the echogenic contrast agent is more effective in blocking gas interference in the gastrointestinal cavity, so clinical There are many applications.
Ultrasound examination of gastrointestinal diseases using contrast agent can form a sharp contrast interface between normal tissue and lesion tissue, and significantly improve the display rate of lesion tissue, especially for small lesions (such as ulcers with a diameter of less than 0.5 cm, ulcers with a diameter of less than 1.0 cm below the mass, etc.), the detection rate can be greatly improved. Moreover, the contrast agent stays in the gastrointestinal cavity for a relatively long time, which gives the inspector sufficient observation time.
2. Is the contrast agent harmful to the human body?
The safety of the contrast agent used in gastrointestinal ultrasonography is relatively high. Its main component is the matured cereal powder, also known as “food-type contrast agent”. Made of dual-purpose traditional Chinese medicine raw materials, there is no obvious adverse reaction, and it will not cause the situation that it cannot be metabolized in the human body.
Therefore, do not have a greater psychological burden during the inspection. Considering that the contrast agent is mainly excreted through the kidneys, drink plenty of water after the gastrointestinal ultrasonography examination, which is conducive to urination. Generally, more than 90% of the contrast agent can be excreted in about 4 hours, and basically can be discharged in about 24 hours. All out. For some patients who cannot eat or drink, you can choose the form of intravenous rehydration to promote the metabolism of the body and promote the excretion of the contrast medium. For some patients with poor renal function, diuretics can be used as appropriate to promote urination.
3. What diseases can gastrointestinal ultrasonography be used for screening?
Gastrointestinal contrast-enhanced ultrasonography is easy to operate and is a non-invasive diagnostic method. It can observe the human gastrointestinal function, such as gastrointestinal motility, tension, emptying, etc., and can be applied to large-scale gastrointestinal disease screening; It can display the hierarchical structure of the gastric wall, display the location, size and shape of the gastric wall cancer, and sometimes judge the extent of the lesion invading the gastric wall, and can be used for early gastric cancer screening. At present, in clinic, gastrointestinal ultrasonography, X-ray barium meal examination, and endoscopy are commonly used to diagnose gastrointestinal diseases, but X-ray barium meal examination and endoscopy cannot observe the gastrointestinal submucosal Therefore, gastrointestinal ultrasonography is mainly used to observe and diagnose gastrointestinal submucosal lesions.
Based on the above, gastric ultrasonography is currently recommended for patients with the following conditions: (1) Symptoms and signs of gastrointestinal diseases, clinical suspicion of tumor lesions, gastric ulcers, foreign bodies in the stomach, esophageal and gastric varices, etc.; ( 2) Identify whether the tumor originates from the stomach, and understand the relationship between the tumor and the stomach wall and/or the invasion of surrounding tissues and organs such as the liver and pancreas; (3) Follow-up patients need to be reexamined dynamically for gastric lesions, such as peptic ulcer and gastric cancer Observation and evaluation of the efficacy of neoadjuvant chemotherapy; (4) Gastric function testing, such as gastric receptivity, emptying dynamics, and gastroesophageal reflux disease, etc.; (5) Those who cannot tolerate or cannot perform gastroscopy, such as Those who are afraid of gastroscopy, children, pregnant women, elderly and infirm, and those with serious underlying diseases who cannot tolerate gastroscopy; (6) Carry out primary screening of gastric diseases in areas with high gastric cancer incidence and among people at risk of gastric cancer.
4. Is there no limitation of gastrointestinal contrast-enhanced ultrasonography?
Of course, no inspection method is perfect. Gastrointestinal contrast-enhanced ultrasonography is easy to miss the diagnosis of ulcers less than 3mm and masses less than 5mm; the observation of gastrointestinal mucosa is not as clear as gastroscope, and the overall observation of gastrointestinal tract is not as clear as X-ray; It is not as accurate as gastroenteroscopy in the qualitative aspect of benign and malignant ulcers.
In addition, gastrointestinal contrast-enhanced ultrasonography cannot be performed in patients with the following conditions: (1) those who need to fast clinically, such as severe gastric retention, gastric or duodenal ulcer perforation, and emergency patients with gastrointestinal trauma; (2) those with severe (3) Severe obesity, abdominal wall hypertrophy, deep or high stomach position, intestinal gas that seriously interferes with gastric ultrasound scanning, etc. Those with low quality of gastric ultrasound imaging; (4) Those who have not had X-ray barium meal examination for more than 24 hours.
5. What should be paid attention to when performing gastrointestinal contrast-enhanced ultrasonography?
(1) Before carrying out gastrointestinal ultrasonography examination, relevant bowel preparations should be made. Those who plan to be examined in the morning should refrain from food, beverages and smoking after 8:00 pm the day before the examination, and eat less dregs and easy-to-digest food for dinner the day before, and avoid eating spicy, hot peppers, etc. Foods that are not easy to digest, such as fried, grilled, and hot pot, or that are prone to gas production, such as beans and sweet potatoes. Those who are scheduled to have the examination in the afternoon can drink sugar water in moderation before 8:00 am that day, but cannot eat other types of food, and fast at noon.
(2) Fasting for breakfast on the day of the examination, fasting for 6-8 hours for adults (except for patients with high blood pressure, heart disease and diabetes, taking routine medication with a small amount of water), and fasting for 3 hours for infants. No smoking before the examination, less talking, and less gas swallowed into the gastric cavity.
(3) Wear loose clothes on the day of the examination, which can quickly and fully expose the examined parts. Also avoid wearing jewelry such as necklaces, so as not to block the inspected part during the inspection. If there is a dressing on the area under examination, it should be removed, and then reapplied after the ultrasound examination.
(4) Before the examination, pour the contrast agent into the cup according to the guidance of the medical staff, first add 100-200ml of hot boiled water and stir well, then heat the boiled water to 500-700ml, stir well for later use, and avoid precipitation and agglomeration , not too sticky. During the examination, 500-700ml of contrast agent prepared orally (the dose can be reduced for children) to fill the gastric cavity.
(5) If the subject has had a barium meal examination before, the barium meal will adhere to the gastric mucosa, especially the lesions of gastrointestinal ulcers are more likely to adhere, so gastroscopy can only be performed 3 days after the barium meal examination.