The ability to look inside the body is a powerful tool for diagnosing medical conditions.
Traditional imaging techniques such as X-ray, ultrasound, magnetic resonance imaging (MRI), and others allow doctors to observe certain conditions from the outside, looking in.
However, an endoscopic ultrasound (EUS) is a procedure that allows doctors to obtain images and information from the inside.
Specifically, this medical procedure combines endoscopy (the insertion of a long flexible tube via the mouth or rectum to visualize the digestive tract) with an ultrasound examination (a diagnostic imaging test that uses high-frequency sound waves to produce images or pictures of internal organs and structures inside the body). Doctors use EUS to obtain images of the internal organs in the chest and abdomen, as well visualize the walls of these organs, or to look at adjacent areas such as lymph nodes. Combined with Doppler imaging (another form of ultrasound), nearby blood vessels can also be evaluated.
Most important, EUS offers the ability to guide a biopsy needle into lesions that are too small to be identified by computed tomography (CT) or MRI, or those that are too well encased by surrounding vascular structures to allow for a traditional needle biopsy, which is performed by puncturing the exterior of the skin.
EUS is most commonly used in the upper digestive tract. A probe is inserted into the esophagus, stomach, and duodenum during the procedure. With its proximity to the pancreas, left part of the liver, and major arteries coming from the abdominal aorta, these can be evaluated thoroughly for any abnormalities.
EUS can be very helpful in determining the origin of certain nodules/tumors arising from the wall of the esophagus, stomach, duodenum and rectum. It also can be used to investigate benign as well as malignant processes involving the pancreas, including pancreatic cysts and cancers. The results of such testing then can be used to determine the stage of cancerous tumors, which in turn helps the surgeon or oncologist establish the best treatment options for the patient.
EUS also may be used for:
Collecting tissue samples from the lymph nodes, liver, pancreas and various locations in the digestive tract. (It often is difficult to obtain these tissue samples using traditional methods such as CT guided biopsies.)
Controlling pain associated with pancreatic cancer by numbing one of the major nerve plexuses that carry the pain signals from the pancreas.
Draining abscesses near the rectum, draining pancreas cysts/pseudo cysts when clinically indicated, or for placing markers to delineate the field of radiation for certain tumors.
A patient undergoing an endoscopic ultrasound will be sedated prior to the procedure. Then an echo endoscope (the device used to perform EUS) is inserted through the mouth or the rectum (depending on which organ is being evaluated) and both endoscopic as well as ultrasound images can be obtained. Samples from abnormal areas will be taken using a small thin needle that passes through the scope to the area of the abnormality. In most cases, a pathologist is present at time of the procedure to read tissue samples as they are taken.
The entire procedure usually takes 45 to 90 minutes, and patients usually can go home the same day of the procedure. EUS is a relatively safe procedure and can be help provide invaluable information to a patient's treatment team.
Dr. Heif is a board-certified gastroenterologist with ProMedica Physicians. For more information, visit promedica.org.