GI Studies
Surgical Cholangiography
Anatomy
Students should be able to identify the following structures on radiographic images:
Liver, Gallbladder, Cystic duct, Right and left hepatic ducts, Common bile duct (CBD), Pancreatic duct, Ampulla of Vater (hepatopancreatic ampulla), Sphincter of Oddi, Duodenum.
Indications, Contraindications, and Patient Preparation
Indications
- To evaluate biliary anatomy and function during or after gallbladder surgery
- To check for residual stones in the common bile duct after cholecystectomy
- To assess patency of bile ducts and sphincter of Oddi
- To investigate unexplained jaundice or biliary obstruction
Contraindications
- Allergy to iodinated contrast media
- Severe infection (e.g., cholangitis) may be a relative contraindication — radiologist will weigh risks
- Unstable surgical patients where prolonged imaging is unsafe
Patient Preparation
- No special prep if intraoperative (performed during surgery)
- If T-tube cholangiography (post-op), patient should be NPO for several hours before the exam
Procedure Types
Intraoperative Cholangiography
CR Location & Positioning
- SID: 40 inches
- Patient position: Supine (on operating table, sterile field maintained)
- Adjustments: Surgical retraction of abdominal wall provides exposure of biliary tract; radiographer positions C-arm ortube over right upper quadrant
- CR: Perpendicular to IR, centered over right upper quadrant to include liver, ducts, and proximal duodenum
- Patient instructions: Not applicable (performed under anesthesia)
- Exposure: Fluoroscopic sequence or digital spot exposures taken as contrast is injected into cystic duct
Evaluation Criteria
- Coverage (what anatomy must be included and how you verify it’s complete): Entire biliary tree visualized — right and left hepatic ducts through the common bile duct and into the duodenum
- Rotation checks (how symmetry or alignment tells you if positioning is correct): Ducts not foreshortened or obscured by surgical instruments
- Motion checks (how sharpness confirms patient cooperation/exposure timing): Sharp ductal margins; no blurring from patient or equipment motion
- Technique checks (what contrast, density, soft tissue visibility, and artifacts to look for): Adequate contrast concentration and exposure for visualization of all ducts
- Clinical aim (when applicable, e.g., reflux, obstruction, displacement, etc.): Confirm ductal anatomy, rule out retained stones or strictures, and verify flow of contrast into duodenum
Postoperative (T-Tube) Cholangiography
CR Location & Positioning
- SID: 40 inches
- Patient position: Supine
- Adjustments: MSP centered to IR; right upper quadrant elevated slightly if needed to separate loops of bowel
- CR: Perpendicular to IR, centered over right upper quadrant (level of right costal margin)
- Patient instructions: Suspend respiration at end of expiration
- Exposure: Single fluoroscopic sequence or series of digital spot images as contrast is injected through T-tube
Evaluation Criteria
- Coverage: Complete opacification of biliary ducts from hepatic confluence to duodenum
- Rotation checks: Spine midline; right ribs equidistant to IR
- Motion checks: Distinct ductal walls; no peristaltic blur
- Technique checks: Appropriate kVp (65–75) for iodinated contrast; no underexposure or burnout
- Clinical aim: Identify residual stones, strictures, leaks, or confirm ductal patency after cholecystectomy
Positioning / Technical Modifications
- For postoperative or debilitated patients, positioning must be gentle and slow to avoid pain or dislodging the T-tube.
- Contrast injection must be slow and under fluoroscopic control to avoid duct rupture or reflux into the pancreatic duct.
- If the patient is unable to assume a supine position, slight left posterior obliquity may improve visualization of the biliary tree.
Exposure Factors & Technical Considerations
- SID: 40 inches
- kVp: 65–75 (lower kVp enhances contrast in biliary system, because we are using iodinated contrast)
- mAs: Short exposure times
- Contrast: Water-soluble iodinated contrast (NEVER barium)
- Imaging equipment: Fluoroscopy with spot or digital capture
- Collimation: Center over right upper quadrant; include liver, ducts, and proximal duodenum
- Shielding: Standard shielding where possible, though limited intraoperatively
Hows & Whys of Surgical Cholangiography
Anatomy
- How does bile normally flow through the biliary system?
Bile flows from the liver through the right and left hepatic ducts → into the common hepatic duct → then through the cystic duct into the gallbladder for storage. During digestion, it passes back through the cystic duct to the common bile duct and into the duodenum via the ampulla of Vater. - How is bile flow controlled?
The Sphincter of Oddi regulates bile release into the duodenum and can become a site of spasm or obstruction. - How do pathologies alter this system?
Stones or strictures block the ducts, preventing bile drainage and leading to jaundice, infection, or pain.
Positioning
- Why is the patient positioned supine for both intraoperative and postoperative cholangiography?
Supine positioning provides stable access to the right upper quadrant, aligns ducts with the x-ray beam, and maintains sterility during surgery or T-tube injection. - Why must the patient’s right upper quadrant be included in every image?
It contains the liver, biliary ducts, and duodenum — all essential for evaluating ductal anatomy and bile flow. - Why is slow, controlled contrast injection required?
Injecting too rapidly can overdistend the ducts or cause contrast reflux into the pancreatic duct, which may lead to pancreatitis. - Why are images taken under fluoroscopy?
Dynamic imaging allows visualization of contrast flow, detection of reflux, and immediate identification of stones or leaks.
Technique & Image Evaluation
- How do you confirm complete ductal filling?
The contrast should opacify the entire biliary tree, including the right and left hepatic ducts, common hepatic duct, cystic duct (if present), and common bile duct, with flow seen entering the duodenum. - How can you identify retained stones or strictures?
They appear as filling defects — round or irregular lucencies within opacified ducts where contrast is displaced or interrupted. - How can you verify proper exposure?
All ducts should appear well defined without overexposure that obscures contrast; use 65–75 kVp for optimal iodine contrast visualization. - How can you distinguish a bile leak from duodenal filling?
A leak appears as extravasation of contrast outside the ductal system that does not progress with time; duodenal filling is contained and peristaltic.
Clinical Applications
- Why is intraoperative cholangiography performed during gallbladder surgery?
It confirms ductal anatomy and ensures no stones remain before the cystic duct is clipped or ligated. - Why is postoperative (T-tube) cholangiography performed several days after surgery?
To evaluate ductal healing, confirm bile flow into the duodenum, and detect retained stones or leaks. - Why is iodinated contrast used instead of barium?
Iodinated agents are water-soluble, safe if leakage occurs, and easily absorbed — whereas barium could cause peritonitis if it escapes the ducts. - Why should the radiologist ensure contrast enters the duodenum?
Flow into the duodenum confirms ductal patency and a functioning Sphincter of Oddi. - Why must communication with the surgical team be constant during intraoperative imaging?
The surgeon manipulates the ducts and controls the injection; real-time coordination ensures safe pressure, adequate visualization, and avoids reflux or rupture.
