Ultrasonography (USG) is a clinical diagnostic method without tissue damage and radiation hazards, and is one of the main contents of veterinary imaging technology. Since the late 1930s, when ultrasound was applied to the medical field, it has gradually formed an independent discipline, Shaosheng Medicine, after more than 30 years of development. The research on its instruments has also developed from the initial A-type ultrasound diagnostic instrument to the current B-type, D-type, M-type and color Doppler ultrasound diagnostic instruments. In particular, the B-type diagnostic instrument can display the tomographic image of the probed part in real time, also known as tomography or cross-sectional imaging, which has brought ultrasound diagnostic technology into a new stage of imaging diagnosis, and is therefore hailed as a revolutionary change in veterinary diagnostic technology. Now, as one of the five major imaging diagnostic technologies (X-ray diagnosis, CT imaging diagnosis, nuclear medicine diagnosis, nuclear magnetic resonance and ultrasound diagnosis), ultrasound diagnosis technology has been unanimously praised by clinical staff for its outstanding characteristics such as high diagnostic accuracy, good repeatability, simple method, no pain, no damage, safety and no side effects. Abroad, this technology plays an important role in basic theoretical research, animal husbandry production practice and veterinary clinical application. Veterinary real-time ultrasound diagnostic instrument can check the pregnancy of animals, as well as the lesions of solid organs such as liver and kidney. It also has good diagnostic value for esophageal infarction, gastrointestinal foreign bodies, effusion diseases (uterine pyometra, pleural effusion, pericardial effusion, etc.) and space-occupying lesions such as hematoma and tumor. Tissue Doppler imaging, as a new echocardiography technology, makes it possible to measure the thickness of the local myocardium of the ventricular wall in order to evaluate the ejection function of the ventricle. In the early 1960s, veterinarians in the United States, Britain and other countries applied ultrasound diagnosis technology to the clinical diagnosis of pregnancy in various dogs. Because of its high diagnostic accuracy and no impact on pregnant female dogs, it is considered to be one of the best diagnostic technologies. It has been clinically proven that its positive accuracy rate is more than 97%, and it can be diagnosed after 18 days of pregnancy. Subsequently, medical staff conducted in-depth research on the diagnosis of other diseases with this technology, proving that ultrasound diagnosis is a diagnostic technology with high diagnostic value. At present, B-mode ultrasound diagnosis technology is widely used in the diagnosis of canine diseases, and is used in the diagnosis of diseases of almost all organ systems. In recent years, B-mode ultrasound has also made certain progress in the diagnosis and treatment of small animals in my country. Animal B-ultrasound examination is easy to operate and non-invasive. The diagnosis of endometritis in dogs and cats and the separation and identification of pathogens can be imaged in real time from multiple angles and dynamically observed. It has incomparable advantages over other imaging examinations. The real-time ultrasound diagnostic instrument is not restricted by special conditions such as the external environment in its application. It can be carried out under normal circumstances and has become an indispensable diagnostic method in clinical practice.

At present, some pet hospitals in China are equipped with imaging diagnostic equipment, and they are mainly concentrated in large pet hospitals in economically developed cities such as Beijing, Shanghai, and Guangzhou. In animal hospitals in developed countries, real-time ultrasound diagnostic instruments are already one of the necessary equipment.

animal B-ultrasound propagates in a straight line in the medium and has good directivity, which is the basis for using ultrasound to detect human organs. When animal B-ultrasound passes through the interface of two adjacent media with different acoustic impedances, the large interface is reflected, and part of the sound energy is refracted in the adjacent medium behind the interface. The ultrasound continues to propagate and reflects again when it encounters another interface until the sound energy is exhausted. The reflected ultrasound is an echo. The greater the acoustic impedance difference, the stronger the reflection. If the interface is smaller than the wavelength, that is, when the interface is small, scattering occurs. Ultrasound also attenuates when propagating in the medium, that is, the amplitude and intensity decrease. Attenuation is proportional to the attenuation coefficient of the medium, inversely proportional to the square of the distance, and is also related to the absorption and scattering of the medium. Real-time (real time) ultrasound diagnostic instrument, also known as B-type ultrasound diagnostic instrument (Brightness mode), referred to as B-mode. Animal B-mode ultrasound is a brightness modulation type, which displays the echo intensity in the form of light spots on the sonogram. The light spots on the sonogram are an important or only basis for ultrasound diagnosis. The stronger the echo signal, the brighter the light spot; the weaker the echo signal, the darker the light spot; no echo is a dark area. The strength of the light spot reflects the strength of the echo interface reflection and attenuation of ultrasound. These light spots, light, and light surfaces constitute a two-dimensional tomographic image of the detected part, that is, the cross-sectional image. Therefore, animal B-ultrasound is also called ultrasonic tomography diagnosis (ultrasonography, USG). The image displayed on its monitor is called sonogram. There are obvious differences in the density of the tissue structure of each organ in the animal body. Animal B-ultrasound technology uses the difference in the absorption and reflection of ultrasound by tissues of different densities to display the cross-sectional images of each organ on the fluorescent screen. The image is an ultrasonic tomographic image, which displays a black and white image against a black background. The white area is a light spot or light group, indicating that there is a density difference between adjacent tissue interfaces; the black area is a non-reflective dark area, indicating that the tissue density is uniform. There are many different imaging methods for animal B-ultrasound, mainly electronic linear array scanning and mechanical sector scanning. In order to obtain ultrasonic echoes in different directions of the detected organ, it is necessary to move or rotate the probe in a certain order, which is particularly important in B-ultrasound diagnosis. The main methods of probe movement include sequential continuous parallel movement method, three-dimensional sector movement method, cross method and contrast pressure method, among which the first two methods are more commonly used.