What is Endoscopic Ultrasound?
In an ultrasound, a piece of equipment called a transducer is used to detect and transmit high frequency sound waves that are emitted from tissues. The sound waves are converted into electrical impulses which are in turn displayed on a monitor as an image of the region of the body being examined. The results of the procedure can then be interpreted by a doctor.
During an endoscopic ultrasound, the transducer is fixed to the end of an endoscope. The endoscope is a long, thin, flexible tube which is fitted with a camera. The endoscope can be inserted into the esophagus or rectum, allowing a doctor to examine the digestive tract.
Combining endoscopy and ultrasound provides a particular advantage over a traditional ultrasound. This is because fixing the transducer to an endoscope means that the transducer can get very close to the regions of the body which the doctor needs to view. The closer the transducer is, the more accurate the images it can generate, so an endoscopic ultrasound can provide more accurate and more highly detailed images than a conventional ultrasound.
Endoscopic ultrasound can be used for staging cancers (such as pancreatic, esophageal, gastric, and rectal cancer), studying tumors in the liver and gallbladder, studying esophageal and rectal muscles, examining the wall of the digestive tract, and evaluating conditions such as chronic pancreatitis. The procedure can also be combined with a fine needle aspiration for biopsy purposes. The fine needle aspiration can take samples of tissue and fluid from organs, muscle, and the digestive tract.
Side Effects from Endoscopic Ultrasound
During an endoscopic ultrasound, a long, thin tube is inserted into the esophagus. The tube passes further through the stomach and into the duodenum. Patients are typically given a sedative to help them relax and a local anesthetic spray in the throat to minimize physical discomfort. The entire procedure is usually over within 45 minutes, and may even take as little as 15 minutes.
Endoscopic ultrasound can often cause sore throat and a bloated feeling that might last for several hours, or until the next day. Slower reaction times are a common result of the sedative, so it is advisable to arrange for a ride home after the procedure, as driving can be dangerous.
Other side effects from endoscopic ultrasound are rare. Occasionally a biopsy site may bleed, but this is not usually cause for alarm. Even so, any pain, fever, or bleeding should be reported to a doctor immediately. These symptoms may indicate an intestinal perforation or infection.
American Society for Gastrointestinal Endoscopy: Understanding Endoscopic Ultrasonography
The Cleveland Clinic: Endoscopic Ultrasound
The Mayo Clinic on Endoscopic Ultrasound
University of Pittsburgh Medical Center Fact Sheet: Endoscopic Ultrasound