Endoscopic ultrasound (EUS) is a procedure used to image the digestive tract, including the pancreas, lesions in the esophagus, stomach and rectum. An endoscope (a thin, flexible, lighted tube) with an ultrasound probe attached to the end is passed through the patient’s mouth into the stomach and the top part of the small intestine called the duodenum. Once in the stomach and duodenum, the endoscopist uses the ultrasound to visualize the pancreas or other digestive organs. If the examination is for a rectal lesion, the endoscope is passed into the rectum.
The images created from an EUS procedure are detailed ultrasound pictures of the digestive tract. The endoscopist will use these images to determine the size and location of a tumor or any other abnormality in the digestive tract. In the cases of a tumor, the endoscopist can survey the area to determine if the tumor is affecting nearby blood vessels, lymph nodes or other structures. EUS can also allow passage of a needle into a suspected tumor or abnormality to obtain tissue samples. This is a type of biopsy called fine-needle aspiration. Cells obtained from the biopsy can then be analyzed to see if they are cancerous and can help in deciding the best course of treatment.