Recently, Mr. Xu, 57 years old in the urban area, found in the physical examination organized by the unit that his liver had grown a large mass of about 3 cm in diameter. He received a new ultrasound examination in the ultrasound department of Nanjing Second Hospital. 10 minutes later, the results came out: diagnosed as liver cancer, later confirmed by surgical pathology. And this new technology is ultrasonography. Wei Qiang, Director of Ultrasound Department of Nanjing Second Hospital, introduced that ultrasonography is to inject microbubble acoustic contrast agent through peripheral vein and use special acoustic contrast technology to detect microbubbles, in order to show the characteristics of blood perfusion of diseased tissues and enhance the contrast difference between diseased and normal tissues, so as to improve the ability of ultrasonography to find foci and qualitative diagnosis. It uses a new contrast agent, sonovan, which is only 2.5 microns in diameter, much smaller than red blood cells (8 microns). After being injected into the bloodstream, it quickly reaches the capillary network of every organ in the body, and can be clearly displayed after a few minutes, and finally exhaled through the lungs and discharged out of the body. The whole process is very brief, usually lasting about ten minutes before disappearing. Studies have shown that ultrasonography is significantly better than conventional ultrasound in the qualitative and quantitative diagnosis of tumors, especially in detecting tiny tumors below 1cm with high sensitivity. Meanwhile, compared with enhanced CT and MRI, real-time ultrasonography has the advantages of being non-radioactive, real-time, and can be repeated many times. At present, ultrasonography has become an important development direction in the field of ultrasound. In recent years, Nanjing No.2 Hospital has taken the lead in carrying out ultrasonography, which is at the forefront of diagnosis and differential diagnosis of liver cancer in the province.