Imaging after Pancreaticoduodenectomy: How Can the Radiologist Help the Surgeon

Abstract

Pancreaticoduodenectomy is the one of the most complex surgeries done for periampullary pathologies. Computed tomography is the imaging modality of choice in the postoperative period. The radiologist should have the knowledge regarding normal findings and complications that can be encountered postsurgery. This will help in quick decision making and timely management of these complex cases.

Keywords

complications - leak - pancreaticoduodenectomy

Introduction

Pancreaticoduodenectomy (PD) is the standard surgical management for malignancies of the head of pancreas, distal common bile duct (CBD), periampullary region, and duodenum which are deemed to be resectable and is also performed in management of selected benign pathologies. As a highly complex surgery, PD, known commonly as Whipple procedure, is associated with very high morbidity.

PD can be performed in two different surgical techniques: classic or conventional Whipple procedure, which involves the resection of pylorus, and pylorus-preserving PD. These surgical techniques are followed by creation of three anastomoses: pancreatojejunostomy (PJ), gastrojejunostomy (GJ)/duodenojejunostomy, and hepaticojejunostomy (HJ; [Fig. 1]).

Fig. 1 Post-Whipple's surgery showing normal postoperative changes: (A) PJ anastomosis, (B) GJ anastomosis, and (C) HJ anastomosis. GJ, gastrojejunostomy; HJ, hepaticojejunostomy; PJ, pancreaticojejunostomy.

With rapid advancement in the surgical techniques and postoperative patient care, the mortality rates have reportedly decreased to <10% from >25% a few decades ago.[1] As operative mortality of this procedure has decreased, postoperative complications both early and late have become more important to identify and therefore require early management. Complications related to PD can postpone the adjuvant treatment of cancer patients and have high health care burden on patients as well as on centers.

Complications post-PD include postoperative abdominal abscesses, hemorrhage, biliary tract injuries or stricture, pancreatic fistulae, hepatic infarction, anastomosis leakage, delayed gastric emptying (DGE) and chyle leak. Computed tomography (CT) represents the standard imaging modality in the evaluation of complications after Whipple procedure due to its availability and lesser acquisition time and its ability to acquire high spatial resolution images of abdominal cavity. Magnetic resonance imaging has a limited role in early postoperative period due to difficulty in respiratory motion management as patients may not cooperate due to pulmonary issues. Magnetic resonance cholangiopancreatography is superior to CT for confirmation of leaks, cholangitis, and strictures.[2]

Imaging findings and complications may differ depending upon the surgical technique used. Hence distinguishing normal postoperative changes from complications and tumor recurrence becomes a challenge.

Expected Postoperative Findings

Postoperative changes can be divided into early and late postoperative findings. Early expected findings reflect the initial postoperative inflammation in the surgical bed which can be seen on imaging within the first 3- to 6-month period after surgery ([Fig. 2]). During the later period (after 3–6 months), inflammatory changes usually subside or may even persist with emergence of new findings. The expected postoperative findings are listed in [Table 1].[3] [4]

Table 1 Expected postoperative CT findings

Early postoperative period	Late postoperative period
Fluid surrounding surgical bed	Pancreatic duct dilatation
Acute anastomotic edema	Pancreatic parenchymal atrophy
Peripancreatic fat stranding	Lymph nodes
Perivascular cuffing	Scarring
Lymph nodes	Steatosis of left hepatic lobe
Pneumobilia	Induration around SMV and SMA
Stents and catheters

Abbreviations: CT, computed tomography; SMA, superior mesenteric artery; SMV, superior mesenteric vein.

Fig. 2 Expected postoperative findings after Whipple's procedure. (A) Mild free fluid (arrows) adjacent to the PJ site. (B) Jejunal wall edema (arrowheads) and fluid retention in subcutaneous space (dashed arrows). (C) Vascular cuffing around SMA (black arrowhead). (D) CECT done after 3 months shows persistent smooth cuffing around SMA (black arrowhead). CECT, contrast-enhanced computed tomography; PJ, pancreaticojejunostomy; SMA, superior mesenteric artery.

Postoperative Complications after Post-pancreaticoduodenectomy

[Table 2] highlights the clinical presentation, complications, and imaging findings post-PD.[5] [6] [7]

Table 2 Postoperative complications after post-pancreaticoduodenectomy

Complications	Clinical presentations	Imaging findings
A. Pancreaticobiliary complications
Clinically relevant postoperative pancreatic fistula (CR-POPF)	Any measurable volume of drain fluid on or after postoperative day 3 with amylase level >3 times the upper limit of normal amylase	Wide open PJ site, air foci around anastomosis, progressive increase in the size of collections on serial CT imaging
Postpancreatectomy acute pancreatitis (PPAP)	Sustained postoperative serum hyperamylasemia for at least the first 48 hours postoperatively associated with clinically and radiologic features consistent with pancreatitis	Inflammatory changes and/or collections in peripancreatic region
Pancreatojejunostomy stricture	Recurrent episodes of acute pancreatitis, features of pancreatic exocrine, and endocrine insufficiency	Pancreatic ductal dilatation and abrupt narrowing at the PJ site
Hepaticojejunostomy leak	Bilirubin concentration in the drain fluid at least three times the serum bilirubin concentration on or after postoperative day 3 or as the need for radiologic or operative intervention resulting from biliary collections or bile peritonitis	Fluid around HJ site, progressive increase in the size of collections on serial CT imaging
Hepaticojejunostomy stricture and cholangitis	Jaundice, fever, and laboratory parameters of biliary obstruction	Abrupt narrowing at HJ site with upstream biliary dilatation
B. Nonvascular complications
Collection/abscess	A localized collection of pus within the peritoneal or retroperitoneal space along with fever, elevated leucocyte count	Low-attenuation collection with rim enhancement
Delayed gastric emptying	Inability to return to a standard diet by the end of the first postoperative week and includes prolonged nasogastric intubation of the patient	Distended fluid-filled stomach
Gastrojejunostomy leak	Abdominal pain and distension	Collection with gas foci adjacent to the anastomotic site. Extraluminal leak on administration of oral contrast
Gastrojejunostomy stricture	Postprandial pain and recurrent episodes of vomiting	Abrupt narrowing at GJ site with distended stomach
Marginal ulcer	Postprandial pain	Edematous gastrojejunostomy site and fat stranding
Afferent limb syndrome/small bowel obstruction	Abdominal pain and vomiting	Dilated afferent loop with transition point at GJ anastomosis
Tumor recurrence	Clinical and radiological features of disease recurrence	Nodular soft-tissue thickening, progressive increase in soft tissue on serial imaging in the surgical bed or surrounding the mesenteric/celiac axis/hepatic vasculature or sometime as regional lymph nodal enlargement, distant metastasis
C. Vascular complications
Postpancreatectomy hemorrhage (PPH)	Defined by 3 parameters: onset, location, and severity. Onset is either early (<24 hours after the end of the index operation) or late (>24 hours); location is either intraluminal or extraluminal; severity of bleeding may be either mild or severe	Active extravasation on angiography
Pseudoaneurysms	Shock, drop in hemoglobin concentration	Vascular outpouching of contrast on angiography
Portal vein/SMV thrombosis	Signs and symptoms of hepatic/bowel ischemia Multiple organ dysfunction syndrome (MODS)	Occlusion on CT angiography or Doppler USG
Organ ischemia/infarction	Signs and symptoms of hepatic/bowel ischemia/infarction Cholangitis	Peripheral wedge-shaped areas of decreased enhancement in liver; nonenhancement in bowel; dilated biliary ducts with small peripheral abscesses

Abbreviations: CT, computed tomography; GJ, gastrojejunostomy; HJ, hepaticojejunostomy; PJ, pancreaticojejunostomy; USG, ultrasound.

Pancreaticobiliary Complications

Clinically Relevant Postoperative Pancreatic Fistula

Pancreatic leak is the most common cause of pathologic fluid collection after surgery.[8] It is also referred to as postoperative pancreatic fistula and occurs when pancreatic secretions leak into the abdominal cavity, either due to leakage from the pancreatic anastomotic site or from the raw pancreatic surface ([Fig. 3]).

Fig. 3 Postoperative pancreatic leak. (A) Eighth postoperative day for distal cholangiocarcinoma, CECT abdomen shows fluid collection adjacent to PJ site (arrows) suggestive of PJ leak and another collection in right subhepatic space (dashed arrows). (B) Another case showing collection with air foci (arrowhead), with defect at the PJ site (black arrows) suggestive of PJ dehiscence. CECT, contrast-enhanced computed tomography; PJ, pancreaticojejunostomy.

Postpancreatectomy Acute Pancreatitis

Postsurgical changes and elevated amylase and lipase levels in the postoperative period make it difficult to detect early postoperative acute pancreatitis especially in milder cases. Severe and delayed cases are much easier to diagnose with CT imaging showing inflammatory changes and/or collections in the peripancreatic region.[9]

Pancreaticojejunostomy Stricture

Recurrent episodes of acute pancreatitis, features of pancreatic exocrine, and endocrine insufficiency with imaging findings of pancreatic ductal dilatation and abrupt narrowing at the PJ site should suggest the diagnosis of stricture ([Fig. 4]).[9]

Fig. 4 Pancreaticojejunostomy stricture. (A) CECT abdomen shows dilated MPD (arrows) with abrupt tapering at PJ site (arrowhead) suggestive of PJ stricture. (B) Oblique-curved MPR image depicting the upstream dilated pancreatic duct proximal to the stricture (arrowhead). CECT, contrast-enhanced computed tomography; MPD, main pancreatic duct; MPR, multiplanar reconstruction; PJ, pancreaticojejunostomy.

Hepaticojejunostomy Leak

Bile leak can occur after PD due to anastomotic leakage or iatrogenic biliary injury and can lead to abscess formation and peritonitis. Risk factors for HJ leak include preoperative hypoalbuminemia, small caliber of the bile duct, and anastomosis of the jejunal loop to CBD rather than the common hepatic duct. HJ leak typically presents with bilious drainage with bilirubin concentration from the surgical drain over three times the level of serum bilirubin, from the third postoperative day ([Fig. 5]).[10]

Fig. 5 HJ leak. (A, B) Coronal CECT images on day 10 postoperative period shows HJ dehiscence (dashed arrows) and collection in subhepatic space (arrowheads) which was bilious in nature suggesting HJ leak. CECT, contrast-enhanced computed tomography; HJ, hepaticojejunostomy.

Hepaticojejunostomy Stricture

Clinically, patients present with increased serum bilirubin and later on the patient can develop cholangitis and abscess formation. CT imaging shows abrupt narrowing at the HJ site with upstream dilatation of intrahepatic ducts, enhancement of wall of bile ducts, and liver abscesses ([Fig. 6]).[3]

Fig. 6 Hepaticojejunostomy stricture: (A) coronal CECT abdomen reveals enhancing thickening (small arrowheads) along the stump of bile duct at the HJ site suggestive of cholangitis. (B) Thick-slab MRCP image demonstrating abrupt narrowing with upstream biliary dilation suggesting stricture (arrowhead). (C) Contrast-enhanced MR image depicting small lesion with peripheral enhancement in the right lobe of liver keeping with cholangitic abscess (dashed arrow). CECT, contrast-enhanced computed tomography; HJ, hepaticojejunostomy; MR, magnetic resonance; MRCP, magnetic resonance cholangiopancreatography.

Nonvascular Complications

Delayed Gastric Emptying

Requirement of nasogastric tube even after 1 week post-surgery is indirect evidence of DGE ([Fig. 7]).[11]

Fig. 7 Delayed gastric emptying. (A) Axial CT image showing mottled contents with fluid (arrows) in stomach lumen. (B) Coronal CT image confirming the same (arrows) and showing postoperative changes. It is important to see gastric wall enhancement to exclude ischemia. CT, computed tomography.

Gastrojejunostomy Leak

Although relatively rare, anastomotic leak at the gastrojejunostomy site needs early identification as it can cause localized abscess and peritonitis. On CT, collection with gas foci can be seen adjacent to the anastomotic site.

Gastrojejunostomy Stricture and Marginal Ulcer

Ischemia and necrosis can cause scarring leading to stricture formation in the late postoperative period. Gastric contents can cause ulcer formation distal to the GJ site with diagnosis usually dependent on endoscopic findings, while sometimes CT imaging can show edematous gastrojejunostomy site and fat stranding.

Afferent Limb Syndrome

Duodenojejunal loop proximal to the gastrojejunal anastomosis is the site of bilio-pancreatic secretions and this bowel section is called an afferent limb. Afferent limb syndrome is a type of closed loop bowel obstruction due to variable causes including tumor recurrence, postoperative edema, adhesions, and stricture development ([Fig. 8]).[3]

Fig. 8 Afferent loop syndrome due to tumor recurrence. Operated case of carcinoma uncinate process. (A) Preoperative CT shows no evidence of residual tumor (curved arrow) at the operative site. (B) Follow-up CECT abdomen reveals soft tissue thickening in the operative bed (arrows). (C) Upstream dilatation of bowel loops proximal to the GJ anastomosis consistent with afferent loop syndrome (dashed arrows). CECT, contrast-enhanced computed tomography; GJ, gastrojejunostomy.

Abscess/Collection

Abscess formation after Whipple procedure occurs when postoperative collections get infected and this can be seen as low-attenuation collection with rim enhancement on CT imaging.[12]

Tumor Recurrence

Recurrence usually occurs as metastatic disease and less commonly as isolated disease recurrence at the surgical bed. On CT imaging, local recurrence manifests as infiltrative soft-tissue thickening in the surgical bed or surrounding the mesenteric or the celiac axis/hepatic vasculature or sometimes as regional lymph nodal enlargement ([Fig. 8]).[3] Comparison with previous imaging and tumor markers is the most important tool to differentiate tumor recurrence from perivascular cuffing. Previous histopathology report of positive surgical margin is also an important predictor of tumor recurrence. Postoperative ¹⁸F-FDG uptake in the surgical bed beyond 3 months post-surgery is usually indicative of residual tumor or recurrence.[13] Positron emission tomography/CT has moderate advantage over contrast-enhanced CT by demonstrating ¹⁸F-FDG uptake in equivocal or nonenlarged nodes.[14]

Vascular Complications

Post-pancreatectomy Hemorrhage

Early-onset hemorrhage is usually due to surgical factors including inadequate hemostasis, slipped ligature, or fresh bleeding at a surgical site. Late-onset hemorrhage occurs days or weeks after the surgery. Major causes for late-onset hemorrhage includes anastomotic leakages, abscess (causing vascular erosions), pseudoaneurysms, and anastomotic ulcers ([Fig. 9]).[8]

Fig. 9 Late-onset postpancreatectomy hemorrhage: (A, B) axial arterial and venous phase showing hyperdense hematoma (arrows) with HU value of around 70 HU in both the phases, which suggest spontaneous or venous origin of the bleed. (C) Coronal CT image showing hematoma (dashed arrows) clearly separate from the liver. CT, computed tomography.

Vascular Thrombosis, Stenosis, and Pseudoaneurysms

The portal vein and the superior mesenteric vein are the most common sites of venous thrombosis after pancreatic surgery. Reconstruction by using prosthetic grafts and a longer duration of surgery are two known risk factors. Thrombosis requires an aggressive course of management as it can lead to ischemia of the affected organs ([Figs. 10] and [11]).

Fig. 10 Portal vein thrombosis. (A) Axial CECT scan shows thrombosis (arrows) in the right branch of portal vein. (B) Coronal CECT scan shows surgical clips (arrowhead) at the HJ site. CECT, contrast-enhanced computed tomography; HJ, hepaticojejunostomy.

Fig. 11 Pseudoaneurysm: (A) axial CECT abdomen showing contrast outpouching (arrow) suggestive of pseudoaneurysm from right hepatic artery. (B) Coronal CECT abdomen showing pseudoaneurysm (arrow) and postsurgical clips (arrowheads). CECT, contrast-enhanced computed tomography.

Organ Ischemia and Infarction

Dual blood supply of liver makes this a very infrequent complication. Factors that predispose to hepatic infarction include hypotension, long duration of clamping of the vessels, known arterial disease or atherosclerotic burden, thrombosis, and intraoperative injuries to vessel.[3] [12] As the biliary tree is supplied only by the arterial system, an arterial compromise can lead to ischemic cholangitis, biliary strictures, or bilomas ([Fig. 12]).

Fig. 12 Ischemic cholangitis: (A) coronal arterial phase CT image showing thrombosed right hepatic artery (dashed arrow) replaced by collaterals. (B) Thick slab MRCP image shows multiple T2-hyperintense lesions (arrows) with unremarkable HJ anastomotic site (arrowhead). (C) Axial T2-weighted image and (D) diffusion-weighted images confirming the diagnosis keeping with multiple liver abscesses (arrows). CT, computed tomography; MRCP, magnetic resonance cholangiopancreatography.

Conclusion

Understanding the spectrum of normal expected findings and complications post-PD is important for radiologists since imaging has become vital for postoperative evaluation. Better patient care and management is dependent upon early recognition of the complications and differentiating them from normal expected findings that are inherent to the complex anatomy of pancreas and complexity of the surgery itself.

Conflict of Interest

None declared.

Acknowledgments

The authors would like to acknowledge Department of Surgical Gastroenterology, Dr. Selvakumar, Dr. Peeyush, and Dr. Lokesh for their support.

Author's Contributions

B.S., S.C., T.S. were involved in conceptualizing the topic, case collection and manuscript preparation. T.Y. was involved in manuscript editing and case collection. V.K.V., S.C.S., J.R.V. were involved in data acquisition, clinical case collection and manuscript review. A.A. was involved in manuscript editing. B.S. is the guarantor of the manuscript.

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Publication History

Article published online:
27 May 2025