Is ultrasound examination harmful to the human body?
The working principle of a color Doppler ultrasound diagnostic device is similar to bat predation, both emitting and receiving processed ultrasound waves to obtain useful information. Ultrasound is a type of sound wave with a frequency higher than 20000 hertz, which is non radioactive and safe for the human body. It is used in various organ systems throughout the body and for prenatal examinations, and is also very safe for pregnant women and fetuses.
Medical ultrasound diagnosis is widely used, which can diagnose and treat certain diseases based on its principles. The most common thing we come into contact with on a regular basis is ultrasound examination of abdominal organs such as liver, gallbladder, pancreas, and spleen; Ultrasound examination in obstetrics and gynecology, such as screening for four-dimensional abnormalities in the uterine adnexa and early to mid stage fetal development, pelvic floor function examination, etc; Ultrasound examination of the urinary and reproductive system, such as kidneys, ureters, bladder, prostate, scrotum, penis, etc; Superficial organs such as thyroid, mammary gland, parotid gland, superficial masses, and surface lymph nodes; In addition, there are vascular and cardiac ultrasound examinations, as well as gastrointestinal ultrasound examinations.
In addition to the conventional examinations mentioned above, ultrasound examination can also be used for brain, eye, skeletal muscle, contrast-enhanced ultrasound, and interventional therapy. Ultrasound probes with different frequencies and focusing methods can be used to examine different organs, with the most commonly used being abdominal low-frequency convex array probes, superficial high-frequency linear array probes, cardiac phased array probes, intracavitary probes, etc.
Q: Is the liquid applied during the examination harmful to the human body?
The coupling agent was applied before the inspection. Coupling agent is a water-soluble liquid, colorless and transparent gel like substance, non-toxic to the human body. After inspection, it can be wiped clean or washed with warm water. The purpose of applying coupling agent is to ensure good contact between the probe and the skin, isolate gas interference, facilitate the transmission of ultrasound, improve imaging quality, and make the image clearer.
Q: Is color ultrasound equivalent to a color television?
Doctor, why is there no color image on the instrument screen? Are you using color ultrasound? "I believe many patients have this question in their hearts. With the continuous development of medical conditions, black and white ultrasound devices have been phased out, and various hospitals are using color ultrasound devices to examine patients.
Why is there a big difference between the screen that doctors see and the color TV at home? Because the basic two-dimensional imaging of color ultrasound diagnostic equipment is black and white display, color imaging is only used when observing normal organ and lesion blood flow, measuring blood flow parameters, and various cardiovascular parameters.
The meaning of the word "color" in ultrasound, in layman's terms, is actually to indicate the presence and direction of blood flow, usually in two colors: red and blue. Doctors use color Doppler to determine whether there is blood supply to the target organ, and to assist in diagnosing diseases by measuring blood flow parameters. So, color ultrasound displays black and white and color, but it is not equivalent to the color TV in your home.
Q: Why does ultrasound examination require fasting?
Ultrasound diagnosis has a high resolution for tissue structure, but on interfaces with high contrast such as solid gas or liquid gas, ultrasound is difficult to pass through and almost completely reflects. If some gas is swallowed with food after eating, it can increase intestinal gas. Some foods, such as soy products, are also prone to producing gas, which limits the penetration of sound waves during abdominal ultrasound examination, resulting in unclear image display. Moreover, when the gastrointestinal tract is filled with food, the food can form the same sound image as lumps and stones, leading to misdiagnosis.
Therefore, when conducting abdominal organ ultrasound examinations, such as liver, gallbladder, pancreas, spleen, kidney, adrenal gland, abdominal large blood vessels, abdominal cavity, retroperitoneum, and intestinal examination, it is necessary to fast for 6-8 hours or more (except for acute abdomen). Milk, eggs, meat, colored drinks, etc. should not be eaten the night before the examination to reduce the interference of gastrointestinal chyme and gas. It can ensure the filling of bile in the gallbladder, avoid gallbladder contraction, and fully display various gallbladder lesions. In addition, for patients with frequent abdominal distension, it is recommended to have a light diet the night before the examination, and take appropriate medication to promote digestion and exhaust before the examination.
Q: Why do some ultrasound examinations require holding urine?
Further urinary ultrasound examinations, such as bladder, ureter, prostate, seminal vesicle examinations, transabdominal gynecological examinations, and ultrasound examinations for pregnant women in the first 3 months of pregnancy, require holding urine. The purpose of holding urine is to fill the bladder, reduce intestinal gas interference, and provide a good sound window for examination. When conducting gynecological examinations, it is generally required that the bladder urine volume be between 400-500 milliliters. The sign of good bladder filling is that the lower abdomen is slightly raised in a supine position, and the probe can be pressed down and tolerated during compression.
Q: Some gynecological ultrasounds require holding urine, while others do not?
Gynecological ultrasound examination can use two types of probes, namely transabdominal and transvaginal ultrasound examination, with different populations: transabdominal ultrasound examination is suitable for all women, including pregnant women; Transvaginal ultrasound is suitable for married women (especially those suspected of endometrial lesions) and pregnant women suspected of having placenta previa.