- Ultrasound. The ultrasound uses sound waves to visualize the bile ducts, liver, and pancreas. When gallstones are present, they are seen in either the gallbladder or bile ducts. Little risk is associated with the ultrasound test. The ultrasound may not see gallstones in obese patients, or in patients who have recently eaten.
- Endoscopic Ultrasound. An endoscopic ultrasound utilizes a scope that has an ultrasound on the end of the instrument. The special ultrasound scope is passed down into the intestines where internal visualization of the bile ducts, gallbladder, and pancreas ducts can occur. Special training is required to use the endoscopic ultrasound which is sometimes used to locate bile duct stones that may be missed by regular ultrasound. Other uses for the endoscopic ultrasound include the diagnosis of pancreatic cancer and cancer of the bile ducts.
- CT Scan. While the CT Scan may identify gallstones, it is usually not as effective as the ultrasound. The CT Scan is also used to diagnose cancer in the liver and pancreas, and is a preferred method of assessing the severity of pancreatitis.
- ERCP or Endoscopic Retrograde Cholangiopancreatography. ERCP is another type of endoscope that allows access to the bile ducts and pancreas ducts. The ERCP enables the performance of treatments that include removing gallstones from the bile ducts or the pancreas ducts. The measurement of the sphincter of Oddi muscle is often performed, utilizing another specialized test called Oddi manometry, during ERCP.
- MRCP or Magnetic Resonance Cholangiopancreatography. MRCP utilizes the MRI or Magnetic Resonance Imaging equipment in a noninvasive test that uses special computer software that creates images of the bile ducts and pancreas ducts in a way that is similar to ERCP without the necessity of the internal scope. When MRCP reveals abnormal results further evaluation or treatment is necessary with ERCP or surgery.
Source: American College of Gastroenterology