Principle: 20,000-1 billion vibrations per second, the human ear can not hear the sound waves called ultrasound. The application of ultrasound good directivity in the human body propagation, due to the various tissues of the human body have acoustic characteristics of the differences in ultrasound in two different tissue interface to produce reflection, refraction, scattering, bypassing, attenuation, and the source of the sound and the receiver of the relative movement of the Doppler shift and other physical characteristics.
Role: To show the morphology of various tissues and their lesions, combined with pathology and clinical medicine, observe, analyze and summarize the different reflection patterns, and make a diagnosis of the location, nature and degree of dysfunction of the lesion.
The development direction of ultrasound in the medical field is color ultrasound.
Color ultrasound is simply a high-definition black-and-white ultrasound coupled with color Doppler. Clinical applications include vascular disease, abdominal organs, and among small organs, the thyroid, breast, eye, prostate and seminal vesicles, and obstetrics and gynecology.
Principle: The Doppler principle calculates the change in frequency of ultrasound echoes (called frequency shift) to detect the speed of moving objects. The blood flow signal obtained by autocorrelation technique is color-coded and superimposed on a two-dimensional image in real time, which forms a color Doppler ultrasound blood flow image. The color Doppler ultrasound (i.e., color ultrasound) has the advantages of two-dimensional ultrasound structural images, and at the same time provides a wealth of information on hemodynamics,
Role: It can quickly visualize the two-dimensional planar distribution of blood flow. It can show the running direction of blood flow, understand the temporal phase and velocity of blood flow, the nature of blood flow, and quantitatively analyze the origin, width, length, and area of blood flow bundles. It can help to recognize vascular and non-vascular lesions, reliably detect shunt and regurgitation, and help to distinguish arteries and veins.
Echocardiography:
Principle: Using radar scanning technology and the characteristics of sound wave reflection, the reflection of ultrasound waves occurring when passing through the various layers of the heart structure is displayed on the fluorescent screen, forming a gray-scale image.
Role: To observe the morphology and structure of the heart and large blood vessels and the beating state, and to understand the law of atrial contraction and diastole and the closing and opening activities of the valves, so as to provide the clinic with reference materials of important value. It is highly accurate, reproducible, simple and non-invasive and painless.