A lower GI endoscopy, or colonoscopy, is a procedure used to get a better look at the entire length of the colon if a person is having symptoms of a lower GI problem or is having a colon screening. A flexible tube about the width of a finger with a light and small video camera at the end is inserted through the anus and into the rectum and colon. Special instruments can be passed through the scope to biopsy or remove polyps, if needed. When having a lower GI endoscopy, it is important to follow the preparation instructions. A clean colon is essential for visualizing and removing polyps or flat lesions that may exist.
An upper GI endoscopy, or esophagastroduodenoscopy, is a procedure to get a better look inside the upper gastrointestinal tract down to the duodenum (first part of the intestinal tract), which includes the esophagus, stomach, and first part of the small intestine, if a person is having symptoms of an upper GI problem. A flexible tube about the width of a finger with a light and small video camera at the end is inserted down the esophagus (food pipe). Special instruments can be passed through the scope to biopsy (take specimens) or different treatments can be done to stretch, widen, or narrow an area of the esophagus.
A sigmoidoscopy is done if it is not necessary to view the entire colon. This procedure also is performed with an endoscope, a flexible tube with a strong light and a camera on it allowing the physician to visualize the lower part of the colon/gastrointestinal tract. The sigmoidoscope is only about 60 centimeters (about 2 feet) long, so the doctor can see the entire rectum but less than half of the colon with this procedure. This test is not widely used as a screening test for colorectal cancer in the United States. When having a sigmoidoscopy, it is important to follow the preparation instructions. A clean colon is essential for visualizing the lining of the sigmoid colon and rectum.