Pancreatic tumors are difficult to do ultrasound examination and are prone to false-negative, so CT is the first choice for the diagnosis of pancreatic tumors in clinical practice, and if necessary, enhanced CT or MRI scan is usually needed to distinguish benign and malignant tumors. Since the pancreas is attached to the retroperitoneal organ with an intestinal canal in front of it, it is easy to be interfered by the liquid and gas of the intestinal canal when doing ultrasound, which leads to unclear image and prevents the ultrasound examiners from making accurate judgment. Therefore, ultrasound is generally not preferred for pancreatic tumors, and CT, enhanced CT or MRI scan is chosen instead.