Virtual Colonoscopy

  • Medical Author:
    Dennis Lee, MD

    Dr. Lee was born in Shanghai, China, and received his college and medical training in the United States. He is fluent in English and three Chinese dialects. He graduated with chemistry departmental honors from Harvey Mudd College. He was appointed president of AOA society at UCLA School of Medicine. He underwent internal medicine residency and gastroenterology fellowship training at Cedars Sinai Medical Center.

  • Medical Editor: William C. Shiel Jr., MD, FACP, FACR
    William C. Shiel Jr., MD, FACP, FACR

    William C. Shiel Jr., MD, FACP, FACR

    Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

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What is colonoscopy?

Colonoscopy is a procedure that enables an examiner (usually a gastroenterologist) to evaluate the appearance of the inside of the colon (large bowel). This is accomplished by inserting a long flexible tube (the colonoscope) that is about the thickness of a finger into the anus and then advancing the colonoscope slowly into the rectum and through the colon. The tip of the colonoscope has a light and a video camera. The inner colon lining can be directly visualized in images transmitted from the camera to a television monitor. This traditional method of examination of the colon is called optical colonoscopy or, more commonly, just colonoscopy.

In preparation for colonoscopy, the day before the examination the colon is emptied using laxatives. Immediately prior to colonoscopy, an intravenous infusion (IV) is started, and the patient is placed on a monitor for continuously monitoring the rhythm of the heart, blood pressure, and the amount of oxygen in the blood. Medication usually is given by IV to make the patient sleepy and relaxed. If needed, the patient can receive additional doses of medication during the procedure. Colonoscopy often gives a feeling of pressure, cramping, and bloating; however, with the aid of the medication, colonoscopy generally is well tolerated and infrequently results in significant pain. The type of anesthesia caused by the intravenous medications is classified as conscious sedation and is safer than general anesthesia. With conscious sedation, patients are sleepy but still arousable, and able to breathe on their own. After the colonoscopy, patients are asked not to drive for the rest of the day if medications for conscious sedation were given.

Should there be polyps (benign growths that can lead to cancer) in the colon, the polyps, almost always can be removed through the colonoscope. Removal of these polyps is an important method of preventing colorectal cancer.

Medically Reviewed by a Doctor on 9/13/2016

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