Postoperative Pancreas

Published on 19/07/2015 by admin

Filed under Radiology

Last modified 19/07/2015

Print this page

rate 1 star rate 2 star rate 3 star rate 4 star rate 5 star
Your rating: none, Average: 0 (0 votes)

This article have been viewed 1897 times

 Small free fluid, edema, and fat stranding in surgical bed with reactive subcentimeter lymph nodes in mesentery

image Mild biliary dilatation, gastrojejunostomy thickening, and pancreatic duct dilatation due to anastomotic edema
image Pancreatic duct stent (thin linear radiodensity) often placed during surgery (traversing pancreaticojejunostomy) to ↓ risk of pancreatic fistula
• Common complications

image Pancreatic fistula: Leakage of amylase-rich fluid from pancreatic duct 

– Focal fluid collection, ectopic gas, or hematoma directly adjacent to pancreaticojejunostomy
image Abscess: Can be intrahepatic, in pancreatic bed, or in subphrenic, subhepatic, or retroperitoneal spaces
image Gastrojejunostomy and hepaticojejunostomy leaks: Suspect when focal fluid collection or ectopic gas in close contiguity to anastomosis
image Postoperative pancreatitis: Fluid, edema, and stranding centered in pancreatic remnant
image Liver infarct: Wedge-shaped areas of hypodensity at periphery of liver
image Postoperative hemorrhage: May be due to bleeding from gastroduodenal artery stump or due to structural abnormality (e.g., pseudoaneurysm)
image Portomesenteric venous thrombosis
image Anastomotic strictures: Suspect when progressive biliary or pancreatic ductal dilatation without obstructing tumor at anastomotic site
image Delayed gastric emptying: Gastric remnant markedly dilated with large retained ingested material and fluid
image Tumor recurrence: Differentiate linear postoperative scarring from nodular, mass-like tumor recurrence

CLINICAL ISSUES

• Whipple procedure mortality has dramatically fallen (was once ∼ 25%, and is now 1-3%)
• Morbidity for Whipple procedure remains considerable, with complications in ∼ 20% of patients
image
(Left) Graphic shows the Whipple (pancreaticoduodenectomy) procedure. Note the common bile duct margin image, the pancreatic margin image, and the intestinal margins image.

image
(Right) This graphic depicts Whipple anatomy: Pancreaticojejunostomy image, choledochojejunostomy image, gastrojejunostomy or duodenojejunostomy image, and cholecystectomy image. The pylorus may be removed or preserved, depending on extent of disease and surgeon preference. Note the ligated gastroduodenal artery image.
image
(Left) Axial CECT demonstrates a collection of fluid and gas image immediately adjacent to the pancreaticojejunostomy in a patient with an elevated drain amylase, compatible with pancreatic fistula. Note the presence of a pancreatic duct stent image.

image
(Right) Axial CECT in a patient with a fever after Whipple procedure demonstrates a thick-walled fluid collection image in the right liver lobe with an internal air-fluid level, compatible with a postoperative hepatic abscess.

TERMINOLOGY

Synonyms

Definitions

• 

IMAGING

General Features

• Best diagnostic clue

image Post Whipple resection: Expected findings include gas in biliary tree, jejunal loop anastomosed to pancreatic neck, gallbladder usually resected
image Post distal pancreatectomy: Expected findings include absent body and tail of pancreas; spleen often resected
• Location
• Surgical procedure determined by location and type of pathology

image Whipple procedure  most commonly performed for tumors of pancreatic head, uncinate, and proximal neck

– Classic Whipple procedure (pancreaticoduodenectomy) involves surgical removal of pancreatic head, gastric antrum, proximal duodenum, and gallbladder
– Pylorus-sparing Whipple procedure, which may theoretically have lower risk of bile reflux, retains pylorus and short segment of duodenum with creation of duodenojejunostomy
– 3 anastomoses created: Hepaticojejunostomy, pancreaticojejunostomy, and gastrojejunostomy (classic) or duodenojejunostomy (pylorus-sparing)
image Distal pancreatectomy performed for tumors of distal pancreatic neck, body, and tail

– May be performed with splenectomy
– Can be performed with en bloc celiac axis resection for some pancreatic body tumors that invade celiac or hepatic artery
image Central pancreatectomy performed for low-risk lesions (low malignant potential) in pancreatic neck/body

– Not used for higher risk lesions due to inadequate lymphadenectomy and ↑ risk of pancreatic fistula
image Enucleation  performed for lesions with low malignant potential that are small and exophytic (often utilized for insulinomas)
image Frey procedure and Puestow procedure are both utilized for treatment of chronic pancreatitis

– Both result in lateral side-to-side pancreaticojejunostomy, with additional resection of portions of pancreatic head in Frey procedure
image Laparoscopic technique is increasingly utilized at high-volume surgical centers (distal pancreatectomy > Whipple procedure)

CT Findings

• Normal findings immediately after Whipple procedure

image Small free fluid, edema, and fat stranding in surgical bed with reactive subcentimeter lymph nodes in mesentery
image Pneumobilia is an expected finding after Whipple procedure due to hepaticojejunostomy
image Mild biliary dilatation frequently present due to anastomotic edema at hepaticojejunostomy
image Thickening at gastrojejunostomy due to edema
image Mild pancreatic duct dilatation due to anastomotic edema at pancreaticojejunostomy
image Pancreatic duct stent (thin linear radiodensity) often placed during surgery (traversing pancreaticojejunostomy) to ↓ risk of pancreatic fistula

– Will eventually pass into bowel over time on its own
image Small free air expected for 14 days after surgery
• Complications

image Pancreatic fistula

– Leakage of amylase-rich fluid from pancreatic duct (either at pancreaticojejunal anastomosis or at site of parenchymal injury)
– Should be suspected when focal fluid collection, greater than expected ectopic gas, or hematoma identified directly adjacent to pancreaticojejunostomy

image Fluid and gas may be visualized in direct contiguity with suture line
image Abscess

– Rim enhancing fluid collection ± internal ectopic gas
– Abscesses following Whipple may be intrahepatic, in surgical bed, or in subphrenic, subhepatic, or retroperitoneal spaces
– Abscesses following distal pancreatectomy are typically in left subphrenic or left subhepatic spaces
image Gastrojejunostomy and hepaticojejunostomy leaks

– Both are uncommon complications, but hepaticojejunostomy leaks are more common
– Should be suspected in acute setting when focal fluid collection visualized in close contiguity to anastomosis (usually with greater than expected ectopic gas)
image Postoperative pancreatitis

Buy Membership for Radiology Category to continue reading. Learn more here