First, the inspection principle is different.
1, the inspection principle of CT is that X-rays will pass through the human body layer by layer, and then be imaged again after computer calculation.
2. The principle of B-ultrasound is to use ultrasound to penetrate the human body. When sound waves meet different tissues, especially the tissue interface, they will produce reflected waves. The ultrasonic probe emits ultrasonic waves and receives reflected waves at the same time. By calculating the reflected waves, an image will be formed.
3. Color Doppler ultrasound is a high-definition black-and-white ultrasound combined with color Doppler, which not only has the advantages of two-dimensional ultrasonic structural images, but also provides rich hemodynamic information.
Second, their respective advantages are different
1, CT examination can be layered, and more organizational information can be displayed after calculation.
2.b-ultrasound can be observed in many directions and imaged in real time.
3. Color Doppler ultrasound has higher resolution, more functions, narrower scope and wider content than B-ultrasound.
Third, their shortcomings are different:
1, CT examination is expensive, and the radiation dose of CT examination is usually higher than that of single x-ray photography.
2.b-ultrasound examination: Because ultrasound is greatly interfered by gas, the accuracy of ultrasonic diagnosis will be reduced for organs with more gas such as intestines, so colonoscopy is generally used for intestinal examination.
3. The influence of color Doppler ultrasound on fetus is greater than that of black-and-white B-ultrasound. Doctors generally recommend that pregnant women do B-ultrasound in the first trimester, and only do color ultrasound in the second trimester to rule out abnormalities or record fetal movements.
Fourth, the clinical application is different.
1, CT examination can show clear structure, which is highly sensitive to the detection of brain and chest lesions.
2.b-ultrasound can check the abdomen and pelvis except the intestine, such as the related examination of the fetus during pregnancy; In addition, superficial organs such as thyroid, as well as solid organs such as liver, spleen, pancreas, kidney and pelvic cavity, have high diagnostic accuracy.
3. Color Doppler ultrasound probes are more, and the exploration area is wider, so that clear blood vessel and blood flow information can be obtained, which has more diagnostic value; Besides the abdominal cavity, it can also be used for the examination of the heart, abdominal organs, superficial skin, eyes and other parts, as well as the examination of the mother and fetus; For small organs such as glands, the examination is more detailed.
References:
Baidu encyclopedia -B-ultrasound examination (B-ultrasound)
Baidu Encyclopedia -CT (Computed Tomography)
Baidu Encyclopedia-Color Doppler Ultrasound