Cholangiography Using Carbon Dioxide Versus Iodinated Contrast in ERCP
Cholangiography Using Carbon Dioxide Versus Iodinated Contrast in ERCP
Carbon dioxide (CO2) gas is widely used for luminal insufflation during endoscopic retrograde
 cholangiopancreatography (ERCP) of the biliary tract. While frequently observed during
 routine ERCP, there are few data on the topic of "air" or "CO2" cholangiography. Our primary
 aim is to compare radiographic cholangiograms in patients with biliary tract disease (from
 stones or strictures) during ERCP obtained by using carbon dioxide as the contrast medium vs.
 conventional iodinated contrast.
It has been recommended that endoscopic retrograde cholangiopancreatography (ERCP) be
 performed using carbon dioxide (CO2) instead of room air as the infused "air" or gas for
 luminal insufflation for reasons of improved patient comfort and in case of procedural
 adverse events (as CO2 is more quickly absorbed by the body and as it can be exhaled via the
 lungs). Air cholangiograms are often incidentally visible on fluoroscopy (radiographically)
 during ERCP prior to injection of iodinated contrast into the biliary tree. Despite the
 information from an air cholangiogram being readily available in many instances, biliary
 endoscopists and radiologists who read the fluoroscopic images taken during ERCP do not
 usually comment or interpret the "air" or "CO2" cholangiograms. Consequently, very little
 data is available on the topic of "air" or "CO2" cholangiography. As a contrast medium for
 cholangiography, CO2 might be safer than iodinated contrast, which is the standard contrast
 medium used during ERCP, as iodinated contrast cannot be easily absorbed by the body and as
 it can be trapped proximal to obstructing biliary stones or strictures and lead to biliary
 tract infection.

 This is a prospective cohort study that will enroll patients undergoing ERCP for suspected
 choledocholithiasis and/or biliary stricture(s). If they did not participate in this study,
 these patients would still require an ERCP with CO2 used as the endoscopically insufflated
 "air" medium. Enrolled patients will undergo an initial cholangiogram with CO2 (injected into
 the bile ducts) utilizing both conventional fluoroscopy and digital subtraction fluoroscopic
 imaging, followed by conventional cholangiography using iodinated contrast (injected into the
 bile ducts). Digital subtraction fluoroscopic imaging is a commercially available setting on
 certain fluoroscopy units that optimizes resolution with air or CO2 used as a contrast
 medium. Findings on CO2 cholangiography will be compared to those obtained from
 pre-procedural abdominal imaging along with the cholangiogram done using iodinated contrast
 at the time of the ERCP procedures.
Inclusion Criteria:

 -  Patients 18 years of age or older

 -  Patients with choledocholithiasis, benign biliary strictures, malignant biliary
 strictures

 -  Biliary pathology suggested or confirmed by imaging with abdominal ultrasonography, CT
 scan, MRI/MRCP scan, or endoscopic ultrasonography (EUS)

 Exclusion Criteria:

 -  Pregnancy (self reported)

 -  Presence of cholangitis before ERCP

 -  Prior history of surgery on the stomach or duodenum that precludes conventional ERCP
 or prior biliary tree surgery (not including cholecystectomy)

 -  Failure to selectively cannulate the bile duct

 -  Life expectancy less than 30 days

 -  Prisoners

 -  Patients unable to give consent