Colonoscopy is the internal examination of the walls of the colon using a flexible fiberoptic tube known as a colonoscope. Colonoscopy is used to diagnose abnormalities of the colon such as colon cancer, colon polyps, bleeding lesions, ulcerative colitis, Crohn's diseases, diverticulitis, unexplained weight loss and chronic diarrhea. Gastroenterologists may also conduct other tests instead of colonoscopy in order to diagnose colon abnormalities.
Barium Enema
A barium enema is an x-ray test in which a white liquid called barium is inserted through the anus into the rectum until it fills the colon. X-ray films of the colon are taken once barium has filled the colon. Barium is a type of contrast that highlights specific areas in the colon, creating a clearer image. Even if barium enema test finds abnormalities in the colon, a colonoscopy may still be required for biopsy and to remove abnormalities. Barium enema may be inaccurate and any abnormalities the test detects may be actually stool.
Flexible Sigmoidoscopy
Flexible sigmoidoscopy is a limited examination of the sigmoid colon. Only the last one-third of the colon is examined. A flexible sigmoidoscope is used to penetrate the anus, rectum and sigmoid colon. Unfortunately, the test does not detect abnormalities that may be present in the upper parts of the colon
Virtual Colonoscopy
According to the National Institute of Diabetes and Digestive and Kidney Disease, virtual colonoscopy is a computerized tomographic scanning of the colon. A tube is inserted in the colon to insert air. A CT scan of the colon is conducted when the colon is inflated. Scans are analyzed and magnified to form virtual images of the colon. A virtual colonoscopy has some advantages. No conscious sedation is necessary and the test takes less than 10 minutes. One disadvantage of virtual colonoscopy is that removal of polyps is impossible because the colon is not observed directly. A regular colonoscopy is necessary so as to remove any abnormalities found during a virtual colonoscopy.
