### activity | examination | endoscopy:

Colonoscopy
* allows a doctor to look inside the colon for bleeding, cancer, and polyps.
* also results in more years of life saved.
* appears to be the most accurate method of screening for colorectal cancer.
* can also identify and treat active bleeding from the bowel
  - confirm the diagnosis of colon obstruction by cancer
  - detect polyps and cancers throughout the entire colon and poses little risk
  - identify a number of pre-cancerous polyps that sigmoidoscopy can miss
* direct visualization of the colon with a flexible sigmoidoscope.
* is an established procedure for evaluating patients with inflammatory bowel disease
  - outpatient procedure
  - covered every two years for beneficiaries at high risk
  - endoscopy
  - indicated only if the polyp is an adenoma
  - more precise than an X-ray
  - necessary to exclude colon cancer and inflammatory bowel disease
  - one of several tests for colon cancer
  - paid for every two years for high-risk patients
  - preferred over barium enema
  - presently the best test available for detecting polyps in the colon
  - recommended every year for a person with a positive gene test
  - safe procedure, with a low risk of complications, but potentially big rewards
* is the gold standard for colon surveillance
  - most direct and complete way to see the entire lining of the colon
  - preferred method of examining the entire length of the colon and rectum
  - screening procedure of choice for hereditary colon cancer
  - standard for screening
  - visualization of the entire colon
* permits the doctor to see much farther into the bowel than sigmoidoscopy
  - physician to visualize the entire colon
* procedure in which the physician uses a longer tube to examine the entire colon
  - performed by a gastroenterologist
  - which enables a doctor to see inside the large bowel
* provides a view of the interior wall of the entire colon and rectum.
* remains the most sensitive test for detecting colon polyps and tumors.
* requires sedation and usually is performed on an outpatient basis in the hospital.
* reveals a large adenocarcinoma in the distal left colon.
* uses an instrument capable of examining the whole colon.
* visual exam of the entire colon, via a flexible scope monitored on a video screen.

### activity | examination | endoscopy | colonoscopy:

Virtual colonoscopy
* allows doctors to see inside the colon without a scope inserted into the rectum.
* involves significant learning for accurate interpretation.
* is used to visualize the surface of the human colon non-invasively in vivo.
* new method for screening asymptomatic patients for colonic polyps
  - test that is being considered as a different way to see the colon

Flexible sigmoidoscopy
* is an examination of the lower colon and rectum
  - as accurate as colonoscopy, but only for the distal bowel
  - effective for only the lower third to half of the colon
* reveals an adenomatous polyp in the rectosigmoid.

Sigmoidoscopy
* also detects colon cancer.
* can even help prevent cancer by detecting polyps before they become cancerous.
* does only examine a portion of the colon.
* involves the rectum and the lower two feet of the colon.
* is endoscopy
* shows erythematous and friable mucosa.

Upper endoscopy
* is more accurate than x rays for detecting inflammation, ulcers, or tumors.
* is performed to exclude cancer as a cause of blockage
  - with a thin, flexible tube that is passed through the mouth
* visual exam of the stomach using a lighted flexible tube.

Virtual endoscopy
* is based on the idea to represent real world objects as spatial information
  - used as a non-invasive diagnostic technique
* promising medical application of volume visualization techniques.