Reducing the size of the pancreas
The pancreas usually decreases in the elderly, but this fact has no clinical significance. With total pancreatic atrophy, a decrease in size occurs in all parts of the pancreas. If there is an impression of isolated pancreatic tail atrophy (the head looks normal), a tumor of the head of the pancreas must be suspected. The head should be examined especially carefully, since chronic pancreatitis in the body and tail area can be combined with a slowly growing pancreatic tumor.
If the pancreas is small, unevenly hyperechoic and heterogeneous in comparison with the liver, the cause of this is often chronic pancreatitis.
Diffuse enlargement of the pancreas
In acute pancreatitis, the pancreas can be diffusely enlarged or may be of normal size and be hypoechoic compared to the adjacent liver. Usually, serum amylase is increased and local intestinal obstruction can be detected as a result of irritation of the intestine.
If the pancreas is unevenly hyperechoic and diffusely enlarged, it is due to acute pancreatitis against the background of the existing chronic pancreatitis.
Local increase (non-cystic)
Almost all pancreatic tumors are hypoechoic compared to normal pancreas. Only by ultrasound it is impossible to distinguish focal pancreatitis and pancreatic tumor. Even if there is an increase in serum amylase, repeat ultrasound 2 weeks later to determine the dynamics. Tumor and pancreatitis can be combined. When there is a mixed echostructure, a biopsy is necessary.
According to ultrasound, it is impossible to differentiate focal pancreatitis from a pancreatic tumor.
True pancreatic cysts are rare. They are usually single, anechogenous, with smooth contours, filled with liquid. Multiple small cysts can be congenital. Abscesses or hematomas of the pancreas will have a structure of mixed echogenicity and are often associated with pronounced pancreatitis.
Pseudocysts, resulting from trauma or acute pancreatitis, occur frequently; they can grow in size and burst. Such cysts can be single or multiple. In the early stages, they have a complex echostructure with internal reflections and fuzzy contours, but in dynamics these cysts acquire even walls, become anechoic and conduct ultrasound well. Pancreatic pseudocysts can be found in any part of the abdomen or pelvis, moving away from the pancreas. When cysts become infected or damaged, internal echostructures or septa can be identified.
Pancreatic cystadenomas or other cystic tumors usually look like ultrasound as cystic lesions with multiple septa, with an accompanying solid component. In microcystatenomatosis cysts are very small and poorly visualized.
Parasitic cysts are rarely found in the pancreas. Conduct an echography of the liver and the rest of the abdomen to eliminate parasitic disease.
Calcifications in the pancreas
Ultrasound is not the best method to detect calcification of the pancreas. It is preferable to perform a radiograph of the upper abdomen in the position of the patient on the back in a direct projection.
Calcifications within the pancreas can give an acoustic shadow, but if they are small, they can look like a separate bright echostructure without an acoustic shade. Calcification usually takes place as a result of:
- Chronic pancreatitis. Calcifications are diffusely distributed throughout the pancreas.
- Stones in the pancreatic duct. These calcifications are located along the course of the duct.
- Gallstones in the distal hola-odna can be mistaken for calcifications in the pancreas. At the same time, however, the extension of the proximal part of the common bile duct is determined.
Expansion of the pancreatic duct
The maximum internal diameter of the normal pancreatic duct is 2 mm, while the duct is better visualized with transverse scanning in the middle third of the body of the pancreas. In order to make sure that you are visualizing the duct, you need to see the tissue of the pancreas on both sides of it. If this is not the case, the spleen vein behind or the stomach wall in front can be misinterpreted as a pancreatic duct.
The walls of the duct of the pancreas must be smooth, and the lumen clean. When the duct is expanded, the walls become uneven; scan not only the head of the pancreas, but also the entire biliary tract.
The reasons for the expansion of the pancreatic duct are:
- Tumor of the head of the pancreas or ampulla of the fater's nipple. Both are combined with jaundice and dilation of the biliary tract.
- Stones of the common pancreatic duct. Conduct a study for the detection of gallstones and dilatation of the bile duct.
- The stone in the intrapancreatic duct. The biliary tract should be normal.
- Chronic pancreatitis.
- Postoperative strictures after Whipl's operation or partial pancreatectomy. It is necessary to clarify the anamnestic data in the patient or, if necessary, with the patient's relatives.
The most common mistakes: with pancreas echography, an incorrect diagnosis can be made as a result of:
- the middle location of the gallbladder;
- enlarged lymph nodes;
- retroperitoneal tumors;
- ascitized ascites or abdominal abscess (including abscess of the spleen);
- cysts or liver tumors;
- cysts of the mesentery;
- hematomas around the duodenum;
- partial filling of the stomach. If the stomach contains a liquid, it can simulate a pancreatic cyst; if it contains food, it can simulate a tumor. The adjacent intestine can cause similar errors;
- kidney cysts, or kidney tumors, or an elongated renal pelvis;
- aortic aneurysms;
- adrenal gland tumors.