Ultrasound and CT are both commonly used abdominal examination methods in clinical practice, and the differences between the two mainly include: 1. CT is the use of radiation, according to the different absorption and transmission rates of X-rays by different tissues of the human body, and is scanned and processed by computer for imaging. Ultrasound examination is safer and has no radiation, while CT examination will produce certain radiation, pregnant women should try to avoid CT examination; 3, examination characteristics are different: abdominal CT is not interfered by gas, substantial organs such as liver, spleen, kidney and cavity organs such as gastrointestinal can be well displayed; but abdominal ultrasound examination is easily interfered by gas, gastrointestinal and other abdominal cavity organs examination has certain restrictions. density of CT examination The resolution of CT examination is better than that of ultrasound, especially after the injection of contrast agent, it is easier to locate and qualitatively diagnose organic lesions such as tumors; ultrasound can monitor blood flow in real time and identify blood vessels and blood flow status in time, and the accuracy of tumor diagnosis can also be improved after the injection of contrast agent. In summary, abdominal ultrasound and CT are two different examination methods, each with its own advantages and disadvantages, which can complement each other.