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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.
Quick GuideScreening Tests Every Man Should Have
What is 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.
Comparing virtual colonoscopy and 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.
New England Journal of Medicine, October 2007
Medically reviewed by John A. Daller, MD; American Board of Surgery with subspecialty certification in surgical critical care
Anderson, Stephan, M.D. "Overview of computed tomographic colonography." UptoDate. Updated Aug. 24, 2015.
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Anderson, Stephan, M.D. "Overview of computed tomographic colonography." UptoDate. Updated Aug. 24, 2015.
Top Virtual Colonoscopy Related Articles
Abdominal Pain (Causes, Remedies, Treatment)
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 FissureAn 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 involves:
- increasing liquid intake,
- using stool softeners,
- prescription medications, and
Blood in the Stool (Rectal Bleeding)
Blood in the stool or rectal bleeding (hematochezia) refers to the passage of bright red blood from the anus. Common causes include
- anal fissures,
- Crohn's disease,
- colon and rectum polyps, and
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 CancerColon cancer is a malignancy that arises from the inner lining of the colon. Most, if not all, of these cancers develop from colonic polyps. Removal of these precancerous polyps can prevent colon cancer.
Colon Cancer PreventionColo-rectal cancer is both curable and preventable if it is detected early and completely removed before the cancerous cells metastasize to other parts of the body. Colonoscopy and flexible sigmoidoscopy (along with digital rectal examination and stool occult blood testing) are both effective at preventing colo-rectal cancers and detecting early colo-rectal cancers.
Colon Cancer ScreeningColon cancer is preventable by removing precancerous colon polyps, and it is curable if early cancer is surgically removed before cancer spreads to other parts of the body. Therefore, if screening and surveillance programs were practiced universally, there would be a major reduction in the incidence and mortality of colorectal cancer.
Colon PolypsColon polyps are common growths on the inner lining of the colon. Colon polyps may become cancerous. There are several different types of colon polyps, and the chance of the polyp becoming cancerous depends on the type, size, and histology. Blood in the stool or rectal bleeding are the most common symptoms of colon polyps. Treatment for colon polyps depend on the type, size, and histology.
ColonoscopyA colonoscopy is a procedure whereby a physician 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 SlideshowColorectal 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.
Crohns Disease vs Ulcerative Colitis UC
Crohn's disease and ulcerative colitis are diseases that cause inflammation of part of or the entire digestive tract (GI). Crohn's affects the entire GI tract (from the mouth to the anus), while ulcerative colitis or UC only affects the large and small intestine and ilium. Researchers do not know the exact cause of either disease. About 20% of people with Crohn's disease also have a family member with the disease. Researchers believe that certain factors may play a role in causing UC. Both Crohn's disease and ulcerative colitis are a type of inflammatory bowel disease, or IBD.
Crohn's disease and ulcerative colitis both have similar symptoms and signs, for example:
- Loss of appetite
- Weight loss
- Episodic and/or persistent diarrhea
- Abdominal pain and cramping
- Rectal bleeding
- Bloody stools
- Joint pain and soreness
- Eye redness or pain
Symptoms unique to Crohn's disease include:
- Skin changes
Symptoms of unique to ulcerative colitis include:
- Certain rashes
- An urgency to defecate (have a bowel movement)
Doctors diagnose both diseases with similar tests and procedures. While there is no cure for either disease, doctors and other health care professionals can help you treat disease flares, and manage your Crohn's or UC with medication, diet, nutritional supplements, and/or surgery.
CDC. "What is inflammatory bowel disease IBD?" Updated June 21, 2017.
NIH. National Institute of Diabetes and Digestive and Kidney Diseases. "Ulcerative Colitis." September 2014.
NIH. National Institute of Diabetes and Digestive and Kidney Diseases. "Symptoms and Causes of Crohn's Disease." November 2016.
NIH. National Human Genome Research Institute. "Learning About Crohn's Disease." Updated: Sep 27, 2011.
PubMed Health. "Ulcerative Colitis." Accessed Jul 24, 2017.
Disease Prevention in MenDisease prevention in men includes routine screening tests that are part of basic prevention medicine. Take an active role in your own health care and discuss screening tests with your doctor early in life. Age of screening and timing of screening depends upon the condition being assessed. Diseases men should take steps to prevent include
- high blood pressure (hypertension),
- type II diabetes mellitus,
- HIV (human immunodeficiency virus),
- colon cancer and colon polyps,
- prostate cancer,
- melanoma and other skin cancer, and
- bladder cancer.
IBS-D Irrititable Bowel Syndrome with Diarrhea
IBS-D or irritable bowel syndrome with diarrhea refers to IBS with diarrhea. Symptoms of IBS-D include
- intestinal gas (flatulence),
- loose stools,
- frequent stools,
- abdominal pain,
- diarrhea, and
New non-FDA approved IBS tests may help diagnose IBS and IBS-D. Treatment of IBS-D is geared to toward managing symptoms with diet, medication, and lifestyle changes.
magnesium citrate-oralMagnesium citrate (Citrate of Magnesia, Citroma) is an OTC product used to relieve constipation and clean the intestines of stool prior to bowel surgery or procedures. Side effects, drug interactions, dosage, and storage should be reviewed prior to using this medication.
Men's Screening TestsGetting 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.
Pelvic Pain in Women and Men
There are numerous causes of pelvic pain in women and men. Causes of pelvic pain in women and men include:
- Pelvic pain during pregnancy
- Fibroid tumors
- Chronic prostatitis
- Sexually transmitted diseases (STDs)
- Kidney stones
- Urinary tract infections (UTIs)
- Low back pain
Treatment of pelvic pain depends upon the cause.
polyethylene glycol (peg) 3350-oralPolyethylene glycol 3350 (Miralax, Glycolax) is a drug used to treat occasional constipation and for bowel preparation prior to procedures. Side effects, drug interactions, dosing, storage, and pregnancy and breastfeeding information should be reviewed prior to using this medications.