When is a cholangiogram (involving percutaneous transhepatic cholangiogram (PTC) or endoscopic retrograde cholangiopancreatography (ERCP)) recommended?

When is Cholangiography (PTC or ERCP) Recommended?

Invasive cholangiography via ERCP or PTC should be reserved for three specific scenarios: obtaining tissue diagnosis when malignancy is suspected, therapeutic biliary decompression in the setting of cholangitis, and palliative stent insertion in irresectable cases—not as a first-line diagnostic tool. 1

Primary Diagnostic Approach

The diagnostic algorithm should begin with non-invasive imaging, not invasive cholangiography:

• Initial screening with ultrasound to exclude gallstones and assess for biliary obstruction 1
• MRI with MRCP as the optimal diagnostic modality for suspected biliary pathology, providing comprehensive assessment of biliary anatomy, duct involvement, and vascular structures without procedural risks 1
• Contrast-enhanced CT for staging and detecting distant metastases, particularly in suspected cholangiocarcinoma 1

MRCP demonstrates superior diagnostic accuracy compared to invasive cholangiography, with sensitivity of 96%, specificity of 85%, and accuracy of 91% versus ERCP's 80%, 75%, and 78% respectively for differentiating malignant from benign strictures 1. MRCP is non-invasive and avoids the significant complication rates associated with ERCP (pancreatitis 3-5%, bleeding 2%, cholangitis 1%, mortality 0.4%) 1.

Specific Indications for Invasive Cholangiography

ERCP is Indicated When:

• Therapeutic biliary decompression is needed in patients with cholangitis or symptomatic obstruction 1
• Tissue diagnosis is required via brush cytology or biopsy in suspected cholangiocarcinoma, though sensitivity remains limited at <50% with standard cytology 1
• Palliative stent placement in irresectable biliary malignancies 1
• Combined diagnosis and treatment in hemodynamically stable trauma patients with suspected pancreatic duct or extrahepatic biliary tree injuries 1

PTC is Indicated When:

• ERCP has failed or is not feasible due to anatomical considerations 1
• Malignant hilar biliary strictures require drainage, where PTC demonstrates 3.5-fold higher therapeutic success compared to ERCP (OR 3.5,95% CI 2.05-5.97), with lower cholangitis rates and fewer reinterventions 2
• Proximal biliary obstruction where local expertise favors percutaneous approach 1

Intraoperative Cholangiography is Indicated When:

• Biliary injury is suspected but not identified during exploratory laparotomy for abdominal trauma 1
• During cholecystectomy when intraoperative findings suggest possible bile duct injury 3

Critical Caveats

Avoid ERCP as initial diagnostic test when non-invasive imaging has not been performed, as nearly one-third of patients with abnormal intraoperative cholangiograms have normal postoperative ERCP, exposing patients to unnecessary procedural risks 4. When extrahepatic obstruction is suspected but therapeutic intervention is uncertain, MRCP or endoscopic ultrasound should be performed first to avoid unnecessary ERCP 1.

Negative cytology does not exclude malignancy—standard brush cytology at ERCP/PTC is positive in only 30-40% of cholangiocarcinoma cases, increasing to 40-70% when combined with biopsy 1.

Special Populations

In trauma patients, ERCP can be used for both diagnosis and treatment in hemodynamically stable or stabilized adults and pediatric patients with suspected pancreatic duct and extrahepatic biliary tree injuries, even in the early post-trauma phase 1. MRCP with hepatobiliary contrast should be considered as second-line non-invasive diagnostic modality to definitively rule out pancreatic and biliary injuries 1.

For suspected cholangiocarcinoma, invasive cholangiography should be reserved until after surgical resectability is established on imaging, to minimize risk of tumor seeding from biopsy 1.