Pancreaticobiliary Imaging Presents Challenges, Opportunities
Imaging insights for pancreatic cancer, pancreatitis and biliary variants
This is the second in a series of articles focused on abdominal imaging. Read the first article in the series.
Knowledge of the imaging features of the pancreas and biliary tree is crucial in optimizing the diagnosis, management and treatment of cancer, pancreatitis and other conditions, according to leading abdominal imaging experts.
Zhen J. Wang, MD, a diagnostic radiologist at the University of California, San Francisco, moderated a case-based course on pancreaticobiliary imaging at RSNA 2025 during which she and three other abdominal imagers discussed the challenges of pancreatic and biliary tree imaging.
As part of her presentation on pancreatic masses, Dr. Wang noted that T1-weighted MRI with fat saturation techniques before the administration of gadolinium contrast can be a useful sequence to visualize small pancreatic lesions.
“The normal pancreas should be the brightest organ in the abdomen on this sequence,” Dr. Wang said. “As a result, focal lesions may stand out against that bright parenchyma, making it helpful for detecting small focal pancreatic tumors.”
Dr. Wang outlined some of the imaging features of malignant pancreatic masses as well as benign mimics and suggested imaging approaches to each. Some pancreatic cancers, she noted, remain challenging to identify even with optimal imaging.
“The iso-enhancing adenocarcinoma that occurs in up to 15% of cases of pancreatic adenocarcinoma is particularly difficult to see,” she said. “Focal ductal dilatation may be the only sign of an isodense tumor.”
Dr. Wang emphasized that such cases often require further workup, including reimaging with MRI or endoscopic US. She emphasized the importance of recognizing indirect imaging signs of malignancy.
“Radiologists should be aware of unexplained segmental pancreatic duct dilation and unexplained distal pancreatitis, as these can be signs of pancreatic adenocarcinoma, and these findings require further diagnostic workup or close surveillance,” Dr. Wang said.
CT Features That Guide Care in Acute Pancreatitis
Acute pancreatitis has its own unique set of imaging findings and can be associated with several often painful complication such as when digestive enzymes, blood and tissue debris leak from the pancreas and accumulate in or around it, forming “walled-off necrosis.”
Kumaresan Sandrasegaran, MBBCh, MD, professor of radiology at Mayo Medical School in Scottsdale, AZ, drew on the Revised Atlanta Classification of acute pancreatitis from 2012 to discuss CT features of acute necrotic collections.
The Classification provides a standardized framework that helps guide clinical communication, categorizing the severity of acute pancreatitis as mild, moderate and severe, based on clinical and morphologic criteria. That framework, he said, helps ensure that findings most relevant to intervention options are clearly conveyed.
According to Dr. Sandrasegaran, important features to report to the surgeon and endoscopist include the size and extent of the collection and its distance from the stomach. He said that varices around the stomach and vascular septa in the collection are also important to note, as their presence may increase the risk of bleeding during treatment.
Reporting templates can help prevent the omission of potentially important findings such as the presence of a thrombus in a vein.
Dr. Sandrasegaran said templates aren’t necessary for minor interstitial pancreatitis but are worthwhile in necrotic pancreatitis because the report must capture many key details and a structured format that helps ensure nothing is overlooked.
Imaging Clues Differentiate CCA from HCC
As with the pancreas, imaging of the biliary tree provides important clues about potentially life-threatening conditions.
“Chronic inflammation of the bile ducts can lead to cholangiocarcinoma (CCA), an aggressive cancer that is often diagnosed at a late stage and carries a five-year survival rate of less than 40%,” said Sree Harsha Tirumani, MD, associate professor of radiology at Case Western Reserve University in Cleveland. “CCA is classified based on anatomic location, pathological subtypes and growth pattern.”
Dr. Tirumani emphasized that both CCA and hepatocellular carcinoma (HCC), the most common types of primary cancers of the liver, tend to develop in the setting of liver cirrhosis. However, mass-forming CCA can be differentiated from HCC by the presence of irregular peripheral enhancement in the arterial phase and progressive central filling on delayed images.
Additional distinguishing features include capsular retraction, peripheral biliary ductal dilatation and vascular encasement without grossly visible tumor thrombus.
“By contrast, HCC typically demonstrates non-rim-like arterial hyperenhancement, non-peripheral washout and a peripheral tumor capsule,” Dr. Tirumani said. “Unlike CCA, HCC often invades portal vein branches contiguously with gross tumor thrombus.”
Biliary Variants with Clinical Consequences
Imaging challenges in the biliary system are not limited to malignancy. Variations in the biliary tree anatomy are common and are well demonstrated with magnetic resonance cholangiopancreatography (MRCP).
Most variants have no clinical relevance, but some carry significant implications for patient care, according to Jeff L. Fidler, MD, professor of radiology at Mayo Clinic in Rochester, MN.
A notable example, he said, is pancreaticobiliary maljunction (PBM), a congenital variant characterized by the bile duct and pancreatic duct joining outside of the duodenal wall. PBM can lead to the reflux of pancreatic fluid into the bile duct and symptoms like pain, fever, vomiting and jaundice. Complications include biliary stones, biliary malignancies and pancreatitis.
“The anomalous pancreaticobiliary junction variant is associated with choledochal cysts and has an increased risk of developing bile duct and gallbladder cancers,” Dr. Fidler said. “Therefore, in the majority of cases, the cyst and gallbladder are removed to prevent the development of malignancy.”
Detection of biliary variants can be important for pre-procedural and preoperative planning in liver and biliary tract surgery and can reduce potential complications. Dr. Fidler described imaging in a patient undergoing evaluation for live donor liver transplant where MRCP revealed three bile ducts draining the right lobe of the liver.
“This variant would have required three bile duct anastomoses and therefore the patient was excluded from donation because of the increased risk for posttransplant complications such as bile duct leaks and strictures,” Dr. Fidler said. “Detection of bile duct and cystic ducts variant can also reduce the risk of complication in patients undergoing laparoscopic cholecystectomy.”
A central takeaway from the session, emphasized by the presenters, was how careful imaging and clear reporting play a critical role in shaping clinical decision-making.
For More Information
Access additional educational resources on pancreaticobiliary imaging at RSNA.org/EdCentral.
Read previous RSNA News stories on abdominal imaging:
- CT Colonography a Better Alternative to FIT and Reliable Alternative to Colonoscopy
- CT Colonography Beats Stool DNA Testing for Colon Cancer Screening
- Radiologists Can Deftly Curb Motion Artifacts in Abdominal MRI