MRCP (Magnetic resonance cholangiopancreatography )

Indication
Evaluation of intra- and extra-hepatic biliary and pancreatic duct dilatation, and the cause of obstruction.

Advantages

Noninvasive. No ionizing radiation. Imaging in all planes. Can image ducts beyond the point of obstruction.

Evaluates extra-luminal disease.

Disadvantages/Contraindications

Special instrumentation required for patients on life support.

Contraindications and risks: Contraindicated in patients with cardiac pacemakers, intraocular metallic foreign bodies, intracranial aneurysm clips, cochlear implants, and some artificial heart valves.

Preparation

Preferably NPO for 6 hours.

Endoscopic retrograde cholangiopancreatography (ERCP)

Indications

Demonstrates cause, location, and extent of extrahepatic biliary obstruction (eg, choledocholithiasis).

Can diagnose chronic pancreatitis.

Primary sclerosing cholangitis, AIDS-associated cholangitis, and cholangiocarcinomas.

Advantages

Avoids surgery.

Less invasive than percutaneous transhepatic cholangiography.

Offers therapeutic potential (sphincterotomy and extraction of common bile duct stone, balloon dilatation of strictures, placement of stents).

Finds gallstones in up to 14% of patients with symptoms but negative ultrasound.

Disadvantages/Contraindications

Requires endoscopy. May cause pancreatitis (1%), cholangitis (<1%), peritonitis, hemorrhage (if sphincterotomy performed), and death (rare).

Contraindications and risks: Relatively contraindicated in patients with concurrent or recent (<6 weeks) acute pancreatitis or suspected pancreatic pseudocyst. Contraindicated in pregnancy because of the potential harm of ionizing radiation to the fetus.

Preparation

NPO for 6 hours.

Sedation required.

Vital signs should be monitored by the nursing staff.

Not possible in patient who has undergone Roux-en-Y hepaticojejunostomy.