Ultrasound room …… Patient A Doctor, can I eat for the ultrasound? Doctor, do I need to hold my urine? Patient B Patient C Doctor, I’m having a color ultrasound, you’re doing it in black and white!
Nowadays, ultrasound is becoming more and more widely used in clinical practice, but as an ultrasonographer, we encounter a lot of the same questions as above almost every day.
Today, we would like to introduce what can and cannot be done with ultrasound.
Ultrasonography
Ultrasonography is a medical imaging technique that uses the acoustic properties of ultrasound to make a clinical diagnosis of disease.
Ultrasound is a type of sound wave that is called ultrasound because the frequency is greater than 20,000 Hz, which is beyond the hearing range of the human ear.
Basic principle of ultrasound imaging
The structure of modern ultrasound diagnostic instruments is relatively complex, so let’s briefly understand the basic principles of ultrasound imaging.
Ultrasound probe emits ultrasound, ultrasound meets the liver and other parenchymal organs can penetrate the past, and use the reflected wave on the ultrasound instrument image, such as meeting the bones and other soft tissue acoustic impedance difference between the structure will be attenuated and total reflection, because it can not penetrate, so can not be visualized.
We can understand the ultrasound simply as a flashlight beam, light can penetrate the air to illuminate a room, but can not penetrate the wall, then the wall can not be displayed behind.
In addition to bone, ultrasound cannot penetrate gas, so remember that ultrasound has two fears: one fears bone and the other fears gas.
Limitations of ultrasound examination Understanding the basic principles of ultrasound imaging, you can better understand the limitations of ultrasound examination.
1, first ultrasound is not applicable to the examination of the skeletal system itself, but ultrasound can be used for the examination of bones, tendons around joints, ligaments and other structures, and the ultrasound of the musculoskeletal system of the ultrasound department of the North Medical College is in the leading position in the country.
2. secondly ultrasonography is not applicable to the respiratory system containing air, but it can be used to diagnose pleural effusion and chest wall tumors.
3. Thirdly, ultrasonography is also not applicable to diagnose early inflammatory changes in the gas-containing gastrointestinal tract, but can diagnose occupying lesions in the gastrointestinal tract.
What can be done by ultrasonography
Cardiac and vascular system ultrasound can be applied to the heart and vascular system, which is usually called echocardiography and vascular ultrasound.
Gynecological and fetal system ultrasound can be applied to gynecological and fetal system. The concept of maternity examination in modern society can be said to be deeply rooted, and it uses ultrasound. Some patients occasionally ask: Is there radiation in ultrasound examination? I usually answer him like this: even the most delicate fetus is examined with ultrasound, adults have even less to worry about!
The third ultrasound examination can be applied to the parenchymal organs of the abdominopelvic cavity, such as the liver, gallbladder, pancreas, spleen and kidneys, etc. The fourth ultrasound examination can be applied to superficial organs, such as the thyroid, breast and testicles, etc.
Next we will answer a few trivia questions.
Why do ultrasound exams require fasting?
There are two main reasons.
The first is to prevent the contraction of the gallbladder, which is an organ for storing bile. In the fasting state, the gallbladder is filled, the wall is thin and smooth, and the ultrasound image is clear, which can truly reflect the maximum volume and shape of the gallbladder and can clearly diagnose the lesion. In contrast, after meal (especially fatty food) will cause gallbladder contraction and bile discharge, and ultrasound will show that the gallbladder volume is reduced and the wall is thick and not smooth, which affects the normal diagnosis.
Secondly, gas will be swallowed with food when eating, so that the intestinal gas increases, and some foods also tend to produce gas, which will limit the penetration of ultrasound, and the image display is not clear, affecting the ultrasound diagnosis.
Why should I hold urine for pelvic examination?
Pelvic ultrasound is mainly used to examine the uterus and ovaries in gynecology. The uterus and ovaries are located in the deep side of the pelvis, and the peristaltic movement of the gas-containing intestinal tubes and their contents in the pelvis before holding urine will interfere with the display of the uterus and ovaries and affect the correct diagnosis.
After the bladder is filled, an echo-free transillumination window can be formed to clearly show the uterus and ovaries behind the bladder and other structures in the pelvis to make a clear diagnosis.
Of course, now with transvaginal ultrasound, it is possible to examine without holding urine, but for unmarried women and other patients who are not suitable for transvaginal examination, it is still necessary to hold urine sufficiently for transabdominal examination.
Ultrasound? Color ultrasound?
Ultrasound is the abbreviation of brightness. Ultrasound is a two-dimensional ultrasound that reflects the internal structure of the body with the brilliance of the echoes of the interface.
Color Doppler ultrasound is a visual representation of the blood flow signal in the blood vessels in red and blue, which is superimposed on a two-dimensional gray-scale image and displayed in real time. In other words, the color signal in “color ultrasound” is the blood flow signal, and the technology is only turned on when the sonographer needs to observe the blood flow at the examination site to aid in the diagnosis.
For example, ultrasound is similar to black and white television, but color ultrasound is not the same as color television. It is more appropriate to combine the two into one called ultrasound.
Ultrasound examination has the advantages of safety, convenience, non-invasive, non-radiation and real-time imaging, and plays a very important role in clinical diagnosis. The value of ultrasound examination can be fully realized.