What is a 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.
What is a virtual colonoscopy?
Virtual colonoscopy is a technique that uses a computerized tomographic (CT) scan (a type of three-dimensional x-ray) to construct virtual images of the colon that are similar to the views of the colon obtained by direct observation by optical colonoscopy.
In preparation for virtual colonoscopy, the day before the examination the colon is emptied using laxatives in a manner similar to traditional colonoscopy. During the examination, a small tube is inserted into the anus to inject and fill the colon with air. Unlike with traditional colonoscopy, this tube is not advanced into the colon. The CT scan then is performed, and the scans are manipulated by computer software to form virtual images of the colon. When properly performed, virtual colonoscopy can be as effective as routine colonoscopy. It can even find polyps "hiding" behind folds that occasionally are missed by traditional colonoscopy. The scanning takes only 10 minutes, and usually no conscious sedation is necessary.
In October, 2007, researchers from University of Wisconsin published in the New England Journal of Medicine a study comparing traditional colonoscopy to virtual colonoscopy. More than six thousand patients over age 50 were evenly divided to undergo either optical or virtual colonoscopy. The researchers found that virtual colonoscopy was as effective as optical colonoscopy in detecting polyps larger than 5mm.

QUESTION
Bowel regularity means a bowel movement every day. See AnswerVirtual colonoscopy vs. traditional colonoscopy
- Virtual colonoscopy is less invasive and faster to perform than traditional colonoscopy and does not require conscious sedation.
- Even though virtual colonoscopy is less invasive than traditional colonoscopy, virtual colonoscopy still involves injecting air into the colon, which can be uncomfortable for some patients. On the other hand, with adequate conscious sedation, patients usually experience little or no discomfort with traditional colonoscopy.
- Virtual colonoscopy is not as reliable as routine colonoscopy in detecting small polyps (less than 5mm in size). Even though most experts believe that polyps smaller than 5mm are usually benign, some small polyps can be cancerous or become cancerous if not removed.
- Virtual colonoscopy is not as accurate as traditional colonoscopy in finding flat cancers or polyps that are not protruding, that is, are not polyp-like.
- Virtual colonoscopy cannot remove polyps. If polyps are found by virtual colonoscopy, then traditional colonoscopy must be performed to remove the polyps. Therefore, many individuals having virtual colonoscopy will have to undergo a second procedure.
- Even though the amount of radiation exposure with virtual colonoscopy is considered safe, the long term radiation effects of mass screening with CT is not known.
My personal approach to recommending virtual versus optical colonoscopies
- In healthy patients who want all the polyps (including ones smaller than 5mm) to be removed, I recommend traditional colonoscopy
- In patients who do not want to undergo routine colonoscopy and are willing to accept the possibility of leaving small polyps untreated, virtual colonoscopy is an alternative.
- In unhealthy patients with advanced heart, lung, liver, or kidney diseases, virtual colonoscopy may be a safer and less invasive alternative to traditional colonoscopy.
REFERENCE:
Anderson, Stephan. "Overview of computed tomographic colonography." UptoDate. Mar. 10, 2019.
Top Virtual Colonoscopy Related Articles
10 Natural Remedies for Colon Cleansing
A colon cleanse is the act of flushing out or cleaning the large intestine. They may be performed by professionals called colonic hygienists. In spite of insufficient research to support its benefits, the goal of colon cleansing is to clear the colon of any stagnant, supposedly toxic waste encrusted on the walls of the large intestine.Abdominal Pain
Abdominal pain can have many causes that range from mild to severe. Some of these causes include bloating, gas, colitis, endometriosis, food poisoning, GERD, IBS (irritable bowel syndrome), ovarian cysts, abdominal adhesions, diverticulitis, Crohn's disease, ulcerative colitis, gallbladder disease, liver disease, and cancers. Signs and symptoms of the more serious causes include dehydration, bloody or black tarry stools, severe abdominal pain, pain with no urination or painful urination. Treatment for abdominal pain depends upon the cause.Anal Fissure
An anal fissure is a small tear or cut in the skin lining of the anus. Pain and/or rectal bleeding during bowel movements are common symptoms of anal fissures. Treatment includes increasing liquid intake, using stool softeners, prescription medications, and surgery.Blood in the Stool (Rectal Bleeding, Hematochezia)
Blood in the stool or rectal bleeding (hematochezia) refers to the passage of bright red blood from the anus. Common causes include anal fissures, hemorrhoids, diverticulitis, colitis, Crohn's disease, colon and rectum polyps, and cancer. The color of the blood in the stool may provide information about the origin of the bleeding. The color of stool with blood in it may range from black, red, maroon, green yellow, gray, or white, and may be tarry, or sticky. Treatment of blood in the stool depends on the cause.Colon Polyps
Colon polyps are fleshy growths inside the colon lining that may become cancerous. Symptoms include rectal bleeding. Learn about causes, signs, treatment, and how to prevent colon cancer.Colonoscopy Procedure and Preparation
A colonoscopy is a procedure whereby a docotor inserts a viewing tube (colonoscope) into the rectum for the purpose of inspecting the colon. Colonoscopy is the best method currently available to diagnose, detect, and treat abnormalities within the colon.Colon Cancer Slideshow
Colorectal cancer (colon cancer) is the cause of many cancer deaths. Learn about the warning signs, symptoms, screening process, stages, and treatment related to colorectal cancer.Does a Right Hemicolectomy Remove the Appendix?
A hemicolectomy is done if the part of the colon that has been infected, damaged or riddled with colon cancer beyond repair. In case of severe appendicitis or in cancer of the appendix, the surgeon will also cut the appendix along with the right colon and connect what's left of your colon to your small intestine.Endoscopy vs. Colonoscopy
Both endoscopy and colonoscopy are nonsurgical procedures that involve use of a flexible tube with a light and camera to examine parts of the digestive tract. A colonoscopy is a type of endoscopy.Is A Colon Resection A Major Surgery?
Colon resection (colectomy) is the surgical removal of part or the entire colon. Colectomy is a major surgery and may take up to four hours for completion. Colectomy is performed under general anesthesia and may require hospitalization for up to a week or more.Men's Screening Tests
Getting the right screening test at the right time is one of the most important things a man can do for his health. Learn at what age men should be screened for prostate cancer, high blood pressure, cholesterol and other health risks.What Is the Difference Between EMR and ESD?
The main endoscopic techniques that are available for the removal of colon (part of the large intestine) polyps or cancer include endoscopic mucosal resection (EMR), endoscopic submucosal dissection (ESD), and polypectomy. Resection removes a part of an organ or a structure. Dissection cuts apart or separates tissue for further study or diagnosis.