Pancreas Flashcards
what is the arterial supply of pancreas?
The coeliac axis and superior mesenteric artery. The head is supplied by the anterior and posterior-superior pancreaticoduodenal arteries. These are branches of the gastroduodenal artery, itself a branch of the hepatic artery. The pancreatic body and tail are supplied by the dorsal pancreatic artery and superior pancreatic branches of the splenic artery, the largest of which is the arteria pancreatica magna.
What is the venous drainage of pancreas?
The pancreatic head is drained by the pancreaticoduodenal veins. These veins may drain directly or indirectly into the portal vein.
The body and tail are drained by several small veins, emptying directly into the splenic vein. The splenic vein lies in a groove on the dorsal-superior margin of the pancreas. The splenic vein joins the superior mesenteric vein posterior to the neck to form the portal vein.
What is teh ductal anatomy of the pancreas?
The pancreatic duct arises from the pancreatic tail and receives numerous short tributaries entering at right angles. This duct drains into the duodenum via the ampulla of Vater and major duodenal papilla.
The anterior and superior portions of the pancreas are drained by the accessory duct of Santorini, either into the duodenum at minor papilla or into the main pancreatic duct. The minor papilla is often not patent as there may be partial or complete obliteration of the accessory duct.
What is the lymphatic drainage of the pancreas?
The neck, body and tail drain via the suprapancreatic and infrapancreatic lymphatic chains and splenic hilar nodes.
The head and neck drains into pancreaticoduodenal and juxtaaortic nodes and porta hepatis nodes.
What CT protocols should be used?
Arterial phase: at 20 seconds following contrast injection. Hypervascular tumours (invariably endocrine) are most readily visible in the arterial phase
Pancreatic parenchymal phase: at 35 seconds following contrast injection. This phase is useful in defining the vascular anatomy in relation to resectability of adjacent tumours
Portal venous phase: at 60-70 seconds following injection of contrast. During this late phase of enhancement, hypovascular tumours (e.g. adenocarcinomas) tend to become more apparent as low density lesions relative to normally enhancing pancreatic tissue
What MR protocol would you use for pancreatic masses?
Images with fat suppression, the pancreas appears homogeneously bright in comparison with the surrounding fat. On this sequence, pancreatic masses and focal pancreatitis stand out as low signal areas.
List three kinds of anomaly that you think could occur due to aldevelopment/malfunction of the development process.
- Annular/semi annular pancreas: this results from incomplete rotation of the ventral portion resulting in either a complete or partial ring of tissue around the duodenum. This may be asymptomatic or produce a degree of obstruction resulting in pain and vomiting.
- Pancreas divisum: this results from failure of fusion of the embryological dorsal and ventral buds. The ducts then remain separate with the dorsal duct draining the body, tail and superior portion of the head into the minor papilla and the ventral duct draining the uncinate process and inferior portion of the head into the major papilla
- Ectopic pancreas tissue
- Short pancreas: this most likely results from agenesis of the dorsal pancreas and may be isolated or in association with polysplenia
How would patients with annular pancreas present with?
Patients may present in the neonatal period or later in adulthood. Symptoms arise from duodenal obstruction. Hence neonates present with vomiting on day 1 with a previous history of polyhydramnios. There are often other anomalies present such as:
- Malrotation
- Duodenal atresias
- Cardiac anomalies
In the adult population, the main presentation is with symptoms of gastric outflow obstruction.
In the neonate, abdominal radiograph looking for double bubble and barium studies should be carried out.
What anomaly is present here?
The pancreatic duct can be seen encircling the duodenum in this CT image of a patient with annular pancreas.
List the three main imaging techniques that may demonstrate pancreas divisum:
- ERCP: There is no communication with the main pancreatic duct. Cannulation of minor papilla is difficult but if achieved, will demonstrate a full length duct of Santorini not in communication with the duct of Wirsung.
- MRCP
- CT
what causes this appearance?
This can be due to causes centred on the bowel wall which include:
Leiomyoma
Brunner gland hyperplasia
Gastric polyp
Lymphoma
Metastatic deposits
Extrinsic lesions can also give this appearance such as a pancreatic tumour or pseudocyst.
In this instance, the lesion was secondary to ectopic pancreatic tissue.
In this instance, the lesion was secondary to ectopic pancreatic tissue.
