Endoscopic ultrasound (EUS), also known as echo-endoscopy, combines the techniques of endoscopy with ultrasound imaging technologies. This combination of procedures and technologies allows doctors to visualize structures within the human body.
- Endoscopy: This minimally invasive procedure involves inserting a long, flexible tube into a hollow organ. The tube is known as an endoscope. Various instruments, such as cameras and curettes (scalpel-like tools), can be attached to the endoscope to perform an array of tasks.
- Ultrasound: This technology utilizes high-frequency sound waves to generate images of structures inside the body. SONAR, a technology developed for the U.S. military, similarly uses sound waves to generate images of structures deep in the ocean.
The endoscopic probe used in EUS procedures contains an ultrasound transmitter. This allows the high-frequency sound waves to travel through the body from an internal location, generating more accurate images. Traditional ultrasound transmits sound waves through the body from an external location. This method of ultrasound imaging is used to visualize a developing fetus in a woman’s womb.
To diagnose cancer, endoscopic ultrasound is used to locate tumors in the following inner-body locations:
- Respiratory Tract: To diagnose cancers of the chest, such as lung cancer, an endoscopic ultrasound probe is inserted into the esophagus through the nose or mouth.
- Lower Gastrointestinal (GI) Tract: To diagnose cancers of the rectum or colon, an endoscopic ultrasound probe is inserted into the large intestine via the anus.
- Upper GI Tract: To diagnose cancers of the upper gastrointestinal tract, such as stomach cancer, esophageal cancer, pancreatic cancer, and various gastric malignancies, an endoscopic ultrasound probe is inserted into the esophagus, stomach, and the first section of the small intestine (duodenum).
What To Expect During an Endoscopic Ultrasound Procedure
EUS is generally performed while the patient is under general anesthesia. Although EUS is known as a minimally invasive procedure, it may affect the patient with mild to severe discomfort.
Very few preparatory measures need to be examined before an upper respiratory or upper GI tract endoscopic ultrasound Typically, you will be asked to fast (not eat) the night before the procedure. It is acceptable to drink clear fluids during this period of fasting.
For lower GI tract EUS procedures, you may be asked to take 2 fleet enemas on the morning of your exam. Fleet enemas clean the bowels by stimulating the processes of waist removal in the intestines.
Endoscopic Ultrasound Risk Factors
Endoscopic ultrasound involves a very low degree of risk. Rarely, however, an EUS procedure may result in the following complications:
- Bleeding: Bleeding is often the result of scratches or abrasions caused by the endoscopic probe sliding against the lining of the esophagus, intestines, or stomach.
- Puncturing: Very rarely, an endoscopic ultrasound probe will puncture the lining of the GI tract, which may cause severe bleeding, and a host of serious complications. If a puncture occurs, it is usually repaired with surgery.
- Drug Reactions: Before you undergo an EUS procedure, inform your doctor of any drug allergies that you may have. Before, during, and after EUS, you doctor may prescribe certain medications to make the procedure more effective. It is important to ask questions about each of these medications and how they might influence your health.
After an EUS
Following an EUS procedure, your doctor will recommend that you rest for a while in the recovery area. This rest will help you overcome any feelings of tiredness or nausea associated with the anesthesia. You may feel bloated or uncomfortable after an endoscopic ultrasound, but these feelings usually subside quickly. Some patients may experience a sore throat after EUS. This is rarely severe, and usually subsided in a matter of hours or days.
It is imprtant to have a friend or family member take you to and from your EUS exam. It is especially imperative for them to drive you home, because the effects of anesthesia can take up to 24 hours to wear off.
