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Imaging Tests of the Liver and Gallbladder


Yedidya Saiman

, MD, PhD, Lewis Katz School of Medicine, Temple University

Reviewed/Revised Aug 2023
Topic Resources

Imaging tests of the liver, gallbladder, and biliary tract include ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI), endoscopic retrograde cholangiopancreatography (ERCP), percutaneous transhepatic cholangiography, operative cholangiography, radionuclide scanning, and simple x-rays.


A type of ultrasonography called Doppler ultrasonography Doppler ultrasonography Ultrasonography is a type of medical imaging that uses high-frequency sound (ultrasound) waves to produce images of internal organs and other tissues. During an ultrasound, a device called a... read more Doppler ultrasonography can show blood flowing through the blood vessels of the liver. Doppler ultrasonography can detect blockages in the liver's arteries and veins, particularly the portal vein, which brings blood from the intestines to the liver. Doppler ultrasonography can also detect the effects of high blood pressure within the portal vein (a condition called portal hypertension Portal Hypertension Portal hypertension is abnormally high blood pressure in the portal vein (the large vein that brings blood from the intestine to the liver) and its branches. Cirrhosis (scarring that distorts... read more ). Endoscopic ultrasonography uses a tiny probe on the tip of an endoscope that is passed through the mouth into the stomach and the first segment of the small intestine (duodenum), bringing the probe closer to the liver and its surrounding organs.

Computed Tomography

Magnetic Resonance Imaging

MRI technology can also provide images of the bile ducts and nearby structures, using a technique called magnetic resonance cholangiopancreatography (MRCP). The images produced are as good as those produced by more invasive tests, in which a contrast agent is directly injected into the biliary and pancreatic ducts. Unlike CT, MRI tests do not involve exposure to x-rays, though they are more expensive than CT and take longer.

Endoscopic Retrograde Cholangiopancreatography

Endoscopic retrograde cholangiopancreatography (ERCP) involves passing an endoscope (a flexible viewing tube) through the mouth, esophagus, and stomach into the duodenum. A thin tube is then inserted through the endoscope into the biliary tract. Doctors inject a radiopaque contrast agent through the tube into the biliary tract, and, at the same time, x-rays are taken of the biliary tract and pancreatic duct.

ERCP is occasionally used simply to see the biliary tract structures, although doctors usually prefer MRCP when available because it is just as good and is safer. However, unlike other diagnostic tests, ERCP allows doctors to do biopsies and certain treatments because an endoscope is used during the procedure. For example, with the endoscope, a stone in a bile duct can be removed, or a tube (stent) can be inserted to bypass a bile duct blockage caused by inflammation or cancer. With ERCP, complications (such as inflammation of the pancreas [ pancreatitis Overview of Pancreatitis Pancreatitis is inflammation of the pancreas. The pancreas is a leaf-shaped organ about 5 inches (about 13 centimeters) long. It is surrounded by the lower edge of the stomach and the first... read more ] or bleeding) occur about 1% of the time. If a treatment is done during ERCP, such complications can occur more often.

Understanding Endoscopic Retrograde Cholangiopancreatography (ERCP)

In endoscopic retrograde cholangiopancreatography (ERCP), a radiopaque dye is introduced through an endoscope (a flexible viewing tube), which is inserted into the mouth and through the stomach into the duodenum (the first segment of the small intestine). The radiopaque dye is injected into the biliary tract just past the sphincter of Oddi. The dye then flows back up the biliary tract and often shows the pancreatic ducts.

Surgical instruments can also be used with the endoscope, allowing a doctor to remove a stone in a bile duct or insert a tube (stent) to bypass a bile duct blocked by scarring or cancer.

Understanding Endoscopic Retrograde Cholangiopancreatography (ERCP)

Percutaneous Transhepatic Cholangiography

Percutaneous transhepatic cholangiography involves inserting a long needle through the skin into the liver and then injecting a radiopaque contrast agent into a bile duct in the liver, using ultrasonography for guidance. The x-rays clearly reveal the biliary tract, particularly any blockage within the bile ducts. Like endoscopic retrograde cholangiopancreatography Endoscopic Retrograde Cholangiopancreatography Imaging tests of the liver, gallbladder, and biliary tract include ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI), endoscopic retrograde cholangiopancreatography... read more (ERCP), percutaneous transhepatic cholangiography is used more often for treatment or biopsy than to obtain images of the biliary tract. Complications of percutaneous transhepatic cholangiography, such as bleeding and internal damage, make it a less desirable method than ERCP, except in special circumstances.

Operative Cholangiography

Operative cholangiography involves the injection of a radiopaque contrast agent directly into the ducts of the biliary tract during gallbladder surgery. X-rays then reveal clear images of the biliary tract. This test is used only occasionally, when other, less invasive tests do not provide enough information.

Radionuclide (Radioisotope) Scanning

Radionuclide (radioisotope) scanning Radionuclide Scanning Radionuclide scanning is a type of medical imaging that produces images by detecting radiation after a radioactive material is administered. During a radionuclide scan, a small amount of a radionuclide... read more uses a substance containing a radioactive tracer that, when injected intravenously, collects in a particular organ. The radioactivity is detected by a gamma-ray camera, which is positioned over the upper abdomen and is attached to a computer that generates an image. A liver scan uses a radioactive substance that collects in liver cells.

Cholescintigraphy (hepatobiliary scintigraphy or scan), another type of radionuclide imaging, follows the movement of a radioactive substance as it is secreted from the liver and passes into the gallbladder and through the bile ducts into the duodenum (the first segment of the small intestine). This technique, which is done after the person fasts, can detect a blocked cystic duct (the tube that joins the gallbladder to the major bile duct—see figure View of the Liver and Gallbladder View of the Liver and Gallbladder View of the Liver and Gallbladder ). Such a blockage indicates acute inflammation of the gallbladder (cholecystitis Cholecystitis Cholecystitis is inflammation of the gallbladder, usually resulting from a gallstone blocking the cystic duct. Typically, people have abdominal pain, fever, and nausea. Ultrasonography can usually... read more ).

X-rays of the Liver and Biliary Tract

Simple x-rays of the abdomen usually cannot detect disorders of the liver, gallbladder, or biliary tract.

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