Visual Representations of ERCP
ERCP produces fluoroscopic images of the biliary and pancreatic ductal systems obtained by injecting contrast through an endoscope positioned in the duodenum, creating cholangiograms and pancreatograms that visualize the anatomy and pathology of these ductal structures. 1
What ERCP Imaging Shows
Technical Procedure and Image Acquisition
ERCP is performed by advancing an endoscope into the duodenum, cannulating the ampulla of Vater, and injecting contrast into the common bile duct (CBD) while obtaining fluoroscopic images to visualize the biliary tree. 1
The procedure captures real-time fluoroscopic images during contrast injection, creating a "roadmap" of the bile ducts and pancreatic ducts. 1
Images demonstrate the intrahepatic bile ducts, extrahepatic bile ducts, common hepatic duct, CBD, cystic duct, and pancreatic duct system. 1
Specific Visual Features on ERCP
In Primary Sclerosing Cholangitis (PSC):
- Multifocal intrahepatic and extrahepatic bile duct strictures creating a characteristic "beaded" appearance 1
- Slight biliary dilatation with diverticular outpouchings 1
- "Pruned tree" appearance in chronic stages 1
In Biliary Obstruction:
- Filling defects representing stones within the ductal system 1
- Strictures with upstream ductal dilatation 1
- Abrupt cutoffs suggesting malignant obstruction 1
In Periampullary Perforation (Type 2):
- Contrast extravasation beyond the normal ductal boundaries 1
- Visualization of retroperitoneal air on fluoroscopy 1
Important Limitations and Pitfalls
Anatomic Variants That Can Confuse Interpretation
Normal anatomic pancreatic and biliary variants can mimic pathology on ERCP, requiring careful interpretation to avoid misdiagnosis. 2
Artifacts associated with the examination technique itself (injection pressure, air bubbles, incomplete filling) can create false impressions of strictures or filling defects. 2
Technical Limitations
ERCP is limited to imaging only the biliary ductal system without visualization of surrounding structures, unlike cross-sectional imaging. 3
The procedure cannot visualize the liver parenchyma, vascular structures, or extrahepatic masses that may be causing ductal compression. 3
In patients with previous gastroenteric anastomoses (such as Roux-en-Y gastric bypass), ERCP is technically difficult as the endoscope cannot easily reach the biliopancreatic limb. 1, 4
Clinical Context: When ERCP Imaging Is Appropriate
ERCP Has Shifted to Primarily Therapeutic Role
Due to advances in cross-sectional imaging (particularly MRCP), ERCP now serves almost exclusively as a therapeutic rather than diagnostic procedure. 1, 3
MRCP should be the principal imaging modality for suspected biliary pathology, with ERCP reserved for cases requiring tissue acquisition or therapeutic intervention. 1, 3
Specific Indications for ERCP Imaging
When therapeutic intervention is anticipated simultaneously (stone extraction, stent placement, sphincterotomy). 1, 3
When MRCP is equivocal or contraindicated and clinical suspicion for biliary pathology remains high. 1
For tissue diagnosis via brushings when malignancy is suspected. 1, 3
In acute cholangitis requiring urgent biliary drainage within 24 hours. 5
Critical Safety Considerations
ERCP carries a 4-5.2% risk of major complications (pancreatitis, cholangitis, hemorrhage, perforation) and 0.4% mortality risk. 1
Cholangitis occurs in less than 1% when proper technique is used. 6
Perforation risk is particularly elevated with sphincterotomy and in patients with altered anatomy. 1, 4