"Voice touches the heart"! Here is everything you want to know about ultrasound examination!

People often ask, "Do all ultrasounds require fasting?", "Why do I need to fast and hold my urine?", "Why is the ultrasound examination so slow?" and many other questions. Today, experts from the Department of Ultrasound Medicine at Hunan Provincial Hospital of Traditional Chinese Medicine have compiled a series of tips on ultrasound examinations for everyone. Let's take a look!

1. What is ultrasound examination?

Ultrasonic detection is like a bat, which detects the surrounding environment by emitting ultrasonic waves and uses echolocation technology to determine the location, shape, speed and other information of objects.

When the ultrasound probe emits ultrasonic waves, these sound waves propagate forward in different tissues of the body at a certain frequency and amplitude, and are reflected back after hitting tissues and organs, and are finally captured by the ultrasound probe.

2. What preparations should be made before the examination?

Like any other medical examination, an ultrasound examination requires some preparation:

1. Under what circumstances should you fast?

The increase in intestinal gas caused by eating will lead to increased ultrasonic reflection, affecting the imaging quality. The gallbladder will shrink due to the discharge of bile after eating, which will affect the doctor's judgment on whether the gallbladder is undergoing physiological or pathological changes. It will also affect the display of lesions in the gallbladder. Therefore, when performing abdominal ultrasound examinations of the liver, gallbladder, spleen, pancreas, etc., you must be on an empty stomach.

2. Why do you need to hold your urine sometimes and urinate sometimes?

It is necessary to hold urine when performing transabdominal exploration of gynecology (such as uterine appendages), urinary system (such as ureters, bladder, prostate), and early pregnancy. Transvaginal and rectal exploration of the pelvic cavity and uterine appendages requires examination after urination.

To what extent should you hold your urine: You can drink 500-1000 ml of water 1-2 hours before the examination. Do not urinate after drinking water, walk more, and hold your urine until you feel the urge to urinate. Signs of a well-filled bladder: When lying flat, the lower abdomen bulges in a shallow arc shape, and you can press down when pressure is applied and you can hold it in.

Special reminder: During the examination, if the doctor finds that you are not ready, he will ask you to hold your urine outside and wait until you are ready for the examination. This is responsible for you and is to give you a clearer examination to avoid missed diagnosis and delayed treatment.

3. What is the sticky stuff that is applied during the inspection?

During an ultrasound examination, the doctor will apply a layer of jelly-like substance to the patient's examination site. In fact, it is a coupling agent, which is a water-soluble colloid, non-toxic, odorless, non-irritating, safe and harmless. After the examination, you can wipe it clean with a paper towel or clean it with water.

The purpose of applying coupling agent is to fill the space between the probe and the skin, exclude air, and ensure good contact, which is beneficial to the conduction of ultrasound, improves imaging quality, and makes the image clearer.

4. What is the difference between B-ultrasound and color ultrasound?

"Doctor, I paid for a color ultrasound, so why is the image on the monitor black and white?"

In everyone's mind, color ultrasound must be colorful, just like a color TV. In fact, this is a misunderstanding of color ultrasound.

Color Doppler ultrasound is an ultrasound diagnostic technology that uses color images to display the direction and relative speed of blood flow in real time based on two-dimensional ultrasound images. Doctors first use "B-ultrasound" to observe the two-dimensional structure, and then use color Doppler blood flow imaging to observe and analyze the blood vessels inside and around the lesion, which is what we usually call "color Doppler ultrasound".

Therefore, color ultrasound is not colorful, and only partially displays red or blue when observing blood flow signals. B-ultrasound can only measure the echo, shape, size, and boundaries of the nodule. However, color ultrasound can further detect whether there is a blood vessel supply in the nodule, thereby inferring the speed of the nodule's growth.

For example, when examining the heart, B-ultrasound can only see the shape of the heart and measure the size of the heart; but color ultrasound can further check the opening and closing of the heart valves, and can also observe the blood flow in the heart, whether there is congenital heart disease, etc.

At present, color ultrasound has basically replaced B-ultrasound. Its examination range is more comprehensive, and its image display rate and resolution are better than B-ultrasound.

5. Why are ultrasound examinations sometimes fast and sometimes slow?

The length of ultrasound examination depends on the part of the patient to be examined and the complexity of the condition. For some patients, the examination time will be relatively short because there are few parts to be examined, the condition is simple, and there are not many abnormalities found; for some patients, the examination time may be longer because there are many parts to be examined or the condition is more complicated. Therefore, sometimes the short examination time does not mean that the doctor is not careful.

6. It’s obviously painful, but the ultrasound results are normal?

Ultrasound examination mainly detects morphological abnormalities. In the early stages of many diseases, there is no obvious change in the morphology of organs.

In addition, ultrasound is not omnipotent due to factors such as gas interference, depth of examination site, and resolution. It is particularly limited in its application in the gastrointestinal tract. In the early stages of many diseases, there is no obvious change in the morphology of organs.

For example, nephritis, early pancreatitis, early appendicitis, etc. are affected by the resolution and examination conditions of the patient during the examination. Therefore, if the ultrasound shows normal results but the patient has obvious symptoms, other examinations should be completed.

7. Why do ultrasound results fluctuate?

This is mostly caused by measurement errors, which is equivalent to measuring the length of an egg. Eggs are oval, and the measurement angle is slightly different, so the results may be different. However, if the recheck value increases significantly in a short period of time, you need to consult a specialist for further advice.

When you find that the ultrasound results are abnormal, don't panic. Ultrasound is only one of the auxiliary examinations. You should complete all the examinations and combine them with the medical history before deciding what to do next. Most tumors require pathological biopsy results for diagnosis. Some benign nodules can also be followed up for observation, and malignant nodules can be further examined and treated.

8. Ultrasound examination precautions

1. Check the upper abdomen, especially the liver, gallbladder, bile duct, pancreas, abdominal blood vessels, etc., which require fasting examination;

2. Check the pelvis, uterus, bilateral adnexa (transabdominal examination), bladder, prostate, seminal vesicles, etc., and the examination needs to be done after the bladder is filled;

3. When checking the blood vessels and thyroid gland in the neck, it is advisable to wear loose and low-necked clothes;

4. When performing intracavitary ultrasound examinations, such as gynecological transvaginal ultrasound examinations, the bladder must be empty.

Hunan Medical Chat Special Author: Zhou Ziyi, Department of Ultrasound Medicine, Hunan Provincial Hospital of Traditional Chinese Medicine

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(Edited by YT)