Noninvasive Diagnosis of Biliary Disease

Summaries for Patients are a service provided by Annals to help patients better understand the complicated and often mystifying language of modern medicine.

Summaries for Patients are presented for informational purposes only. These summaries are not a substitute for advice from your own medical provider. If you have questions about this material, or need medical advice about your own health or situation, please contact your physician. The summaries may be reproduced for not-for-profit educational purposes only. Any other uses must be approved by the American College of Physicians.

The summary below is from the full report titled "Magnetic Resonance Cholangiopancreatography: A Meta-Analysis of Test Performance in Suspected Biliary Disease." It is in the 7 October 2003 issue of Annals of Internal Medicine (volume 139, pages 547-557). The authors are J. Romagnuolo, M. Bardou, E. Rahme, L. Joseph, C. Reinhold, and A.N. Barkun.

What is the problem and what is known about it so far?

Bile is a thick fluid secreted by the liver and stored in the gallbladder. It is then released into the upper intestine to help digest food and break down fats. Bile travels from the liver to the gallbladder and the intestine through canals called ducts. Diseases such as stones and cancer can clog the ducts. Doctors can use several tests to diagnose clogged or obstructed biliary tract ducts. Many are "invasive" tests: They require putting a tube down the patient's mouth, injecting dye through a vein, or inserting a needle into the liver. A relatively new noninvasive test is magnetic resonance cholangiopancreatography (MRCP). This test takes detailed pictures of bile and the biliary tract. Many studies have examined the accuracy of MRCP for diagnosing biliary disease compared with other tests. Do these studies show that MRCP is an accurate test in certain situations and not in others?

Why did the researchers do this particular study?

To summarize results of several studies that looked at how well MRCP detects different types of biliary disease.

Who was studied?

4711 patients who had been in 67 studies comparing MRCP with other tests to detect biliary tract obstruction.

How was the study done?

Rather than do a new study, the authors searched medical literature published from January 1987 through March 2003. They selected published studies if the study compared MRCP with another standard test for detecting biliary disease. Most of the comparison standard tests were invasive procedures. By using a type of analysis called meta-analysis, the authors grouped and combined the results from all of the studies to see whether MRCP was as good as the other tests in detecting certain types of biliary disease.

What did the researchers find?

MRCP was accurate for detecting biliary tract obstruction and compared well with most other tests. It appeared slightly less sensitive for diagnosing stones (92%) and for distinguishing benign from malignant obstruction (87%) than for identifying the presence (99%) and actual site or level (96%) of obstruction.

What were the limitations to the study?

Some reviewed studies had weak designs. Some of the accuracy estimates for detecting different types of biliary disease were imprecise.

What are the implications of the study?

MRCP is an accurate, noninvasive test for diagnosing biliary tract obstruction. It usually correctly identifies the presence and level of obstruction. However, it detects some causes of obstruction better than others. It appears slightly less sensitive in detecting stones and in distinguishing benign from malignant causes of obstruction.