DEAR MAYO CLINIC: My doctor suggested I have an endoscopic ultrasound. What can I expect? Is it safe?

ANSWER: Endoscopic ultrasound is a test that uses a special endoscope to look inside the body for disease. It's similar to other endoscopic procedures that are used to examine areas inside the body. But endoscopic ultrasound has the added benefit of allowing your doctor to produce and record detailed ultrasound images from deep within the body. The test is generally safe, and the risks associated with it are low and comparable to other endoscopic procedures.

Endoscopy allows doctors to visually inspect the inside of the gastrointestinal tract. A typical endoscope is a long, slender, flexible tube with a tiny light and camera at the end. The key difference with an endoscopic ultrasound is the addition of an ultrasound transducer at the tip of the device. Even with the transducer, the endoscope used for an endoscopic ultrasound is about the same size as a regular endoscope.

Ultrasound uses high-frequency sound waves to produce precise images of structures within your body. The images produced during an ultrasound exam can provide information that's valuable in diagnosing and treating many diseases and conditions.

Endoscopic ultrasound is used for a wide variety of noncancerous (benign) and cancerous (malignant) conditions. For example, endoscopic ultrasound can be used to determine the stage of cancerous tumors in the gastrointestinal tract, such as those in the esophagus, stomach and rectum.

During cancer staging, the images produced by endoscopic ultrasound can help determine the size of a tumor, whether the cancer has spread to other parts of the body and, if it has spread, the areas affected by the cancer, such as lymph nodes or nearby organs. That staging information can help doctors determine the appropriate treatment, including surgery, chemotherapy and/or radiation therapy.

Endoscopic ultrasound is also an excellent way to examine the pancreas. It's often used to look for pancreatic problems such as pancreatitis -- an inflammation of the pancreas -- tumors, cysts or other disorders.

Endoscopic ultrasound is performed on an outpatient basis, in a manner similar to other endoscopic procedures. The person undergoing endoscopic ultrasound first receives a sedative, so he or she is comfortable throughout the process. The endoscope is then inserted either through the mouth or the rectum, depending on whether the upper or lower gastrointestinal tract is being examined. The doctor visually inspects the area in question and takes ultrasound pictures that can be further examined later. If necessary, a tissue sample for biopsy can also be taken during an endoscopic ultrasound. The entire procedure usually lasts less than one hour, and patients generally can go home about an hour after the test is finished.

Endoscopic ultrasound carries risks similar to other endoscopic procedures. These include a small risk of bleeding and infection, as well as risk of a tear (perforation) in the wall of the gastrointestinal tract. In addition, a pancreatic biopsy performed via endoscopic ultrasound also carries a small risk of causing inflammation of the pancreas (pancreatitis). The risk of pancreatitis from the biopsy is about 1 to 2 percent.

If you have questions about why an endoscopic ultrasound has been recommended in your situation, or if you would like additional information about the risks and what you can expect, talk to your doctor. In general, endoscopic ultrasound is a safe procedure that can be very helpful in diagnosing, staging and determining appropriate treatment for many gastrointestinal disorders. -- Douglas Faigel, M.D., Gastroenterology, Mayo Clinic, Scottsdale, Ariz.

Medical Edge from Mayo Clinic is an educational resource and doesn't replace regular medical care.

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