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.
Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.
Virtual colonoscopy is a new technique that uses CT to construct virtual images of the colon that are
similar to the views of the colon obtained at colonoscopy. The virtual colonoscopic images are
produced by computerized manipulation of two-dimensional images obtained by
a CT scanner rather than direct observation through the colonoscope. The
colon is cleaned-out using laxatives the day prior to the
virtual colonoscopy examination. A tube then is inserted into the anus and is
used to inject air into the colon. The CT scans then are performed, and the
scans are analyzed and manipulated to form a virtual image of the colon.
Properly performed virtual colonoscopy can be very good. It can even find polyps "hiding
"behind folds that occasionally are missed by colonoscopy. Nevertheless, virtual
colonoscopy has several limitations. They are:
Virtual colonoscopy cannot find small polyps (less
than 5 mm in size) that are easily seen at colonoscopy.
Virtual colonoscopy is not as accurate as colonoscopy at finding flat cancers or premalignant lesions
that are not protruding, that is, are not polyp-like.
Small pieces of stool can look like polyps on virtual
colonoscopy and lead to a diagnosis of polyps when there are none.
Virtual colonoscopy cannot remove polyps. Thirty to
forty percent of people have colon polyps. If polyps are found by virtual
colonoscopy, then colonoscopy must be done to remove the polyps, and,
therefore, many individuals having virtual colonoscopy will have to undergo a
second procedure, colonoscopy.
There have not been studies to compare the discomfort levels of
colonoscopy versus virtual colonoscopy, and comparisons will be difficult to do.
The discomfort of colonoscopy is from the insertion of the colonoscope and air
insufflation. The discomfort of virtual colonoscopy is from air insufflations.
Patients' perceptions of discomfort from both procedures are highly variable.
What makes the discomfort difficult to compare is that patients undergoing
colonoscopy usually are sedated intravenously, while patients undergoing virtual
colonoscopy are not sedated. As a result, patients may actually find colonoscopy
more comfortable than virtual colonoscopy. On the other hand, sedation increases
the risk of complications from colonoscopy.
Because of these limitations, virtual colonoscopy has not replaced
colonoscopy as the primary screening tool for individuals at either normal or
high risk for polyps or colon cancer. It is currently a good option for
individuals who cannot or will not undergo colonoscopy
Abdominal pain is pain in the belly and can be acute or chronic. Causes include inflammation, distention of an organ, and loss of the blood supply to an organ. Abdominal pain can reflect a major problem with one of the organs in the abdomen such as the appendix, gallbladder, large and small intestine, pancreas, liver, colon, duodenum, and spleen.
Colon 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.
Ulcerative colitis is a chronic inflammation of the colon. Symptoms include abdominal pain, diarrhea, and rectal bleeding. Ulcerative colitis is closely related to Crohn's disease, and together they are referred to as inflammatory bowel disease. Treatment depends upon the type of ulcerative colitis diagnosed.
Inflammation of the inner lining of the colon is referred to as colitis. Symptoms of the inflammation of the colon lining include diarrhea, pain, and blood in the stool. There are several causes of colitis including infection, ischemia of the colon, inflammatory bowel disease (Crohn's disease, Ulcerative colitis, or microscopic colitis). Treatment depends on the cause of the colitis.
Cancer is a disease caused by an abnormal growth of cells, also called malignancy. It is a group of 100 different diseases, and is not contagious. Cancer can be treated through chemotherapy, a treatment of drugs that destroy cancer cells.
A colon polyp is a benign tumor of the large intestine. Benign polyps do not invade nearby tissue or spread to other parts of the body. Benign polyps can easily be removed during colonoscopy and are not life threatening. If benign polyps are not removed from the large intestine, they can become malignant over time.
Anal cancer, cancer located at the end of the large intestine, has symptoms that include anal or rectal bleeding, anal pain or pressure, anal discharge or itching, a change in bowel movements, and/or a lump in the anal region. Treatment for anal cancer may involve radiation, chemotherapy, or surgery and depends upon the stage of the cancer, its location, whether cancer is eradicated after the first treatment, and whether the patient has HIV.
Though it's difficult to say why some people develop cancer while others don't, research shows that certain risk factors increase a person's odds of developing cancer. These risk factors include growing older, family history of cancer, diet, alcohol and tobacco use, and exposure to sunlight, ionizing radiation, certain chemicals, and some viruses and bacteria.
Digestion is the complex process of turning food you eat into the energy you need to survive. The digestive process also involves creating waste to be eliminated, and is made of a series of muscles that coordinate the movement of food.
Gardners' syndrome, or familial adenomatous polyposis (FAP), is an inherited condition in which cancer of the colon and rectum develop. Colon polyps and growths may develop as early as the teens. If these polyps are not removed, they will become cancerous. There are different inheritance patterns for familial adenomatous polyposis.
Disease 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.
Disease prevention in women includes screening tests that are a basic part of prevention medicine. All screening tests
are commonly available through your general doctor. Some specialized tests may be available elsewhere.
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