Ultrasonography is a new technique in ultrasound imaging, which is an imaging tool to visualize large vessels to capillaries by intravenous injection of ultrasound contrast agent and to observe the enhancement pattern and degree of enhancement of the lesion part to further evaluate the lesion. The ultrasound contrast agent is a 2-5 micron microbubble, which consists of inert gas (commonly sulfur hexafluoride) and phospholipids or albumin composed of the bubble wall, the bubble into the blood increases the reflection interface in the blood, so that the blood in the sonogram more obvious, clear display. Speaking of which, some people may be worried about how to get out of the inert gas into the body, will not cause air embolism ah? Do not worry, sulfur hexafluoride can be eliminated from the body through the pulmonary circulation, no adverse effects on the body. The phospholipids or albumin in the bubble wall of the ultrasound contrast agent are metabolized in the blood as nutrients after the bubble ruptures. Ultrasonography can be simply understood as enhanced ultrasound, so what is the difference between enhanced ultrasound and enhanced CT and enhanced MRI? Adverse reaction rate is much higher than ultrasonography (1/10000), ultrasonography microbubble only in the blood circulation will not enter the tissue interstitial, inert gas through the lungs to exclude the body, metabolism time is short, the incidence of adverse reactions is extremely low, no higher requirements for liver and kidney function, and no radiation, such a bubble is really excellent. So what can this amazing bubble be applied to? At present, ultrasonography is more maturely used in the diagnosis of liver lesions, interventional treatment, postoperative efficacy observation and follow-up. Ultrasonography is also used in other organs of the abdomen, but it is not as widely used as CT and MRI. In addition, ultrasonography also has outstanding advantages in the diagnosis of peripheral vascular and small organ lesions. For example, in the assessment of the stability of carotid plaque, ultrasonography can clearly show the microscopic neovascularization within the plaque that conventional ultrasound cannot show, and evaluate the stability of the plaque by observing the number and distribution of neovascularization and the surface morphology of the plaque, which can answer the patient’s concern of “whether the plaque will fall off”. Ultrasonography of thyroid nodules also provides a more appropriate test for patients who are concerned about the malignancy of the nodules but do not want to undergo invasive testing. The nodule is further evaluated for benign and malignant tendencies by the way it is enhanced and the degree of enhancement. Ultrasonography can also be used for luminal imaging, such as tubal imaging, anal fistula and intestinal fistula imaging, which can be observed dynamically in real time and without radiation, with high utility and patient compliance. The magic of this bubble lies not only in the diagnosis of the disease, but more importantly in its therapeutic role. Since microbubbles in ultrasound contrast agents can enhance the cavitation effect, the application of ultrasound contrast agents in therapeutic directions such as ultrasound thrombolysis, mediated gene transfection, targeted drug delivery and high-intensity focused ultrasound is expanding and its application value is increasing.