COLONOSCOPY

Inside a bottom

Colonoscopy

Colonoscopy is a technique that doctors use to look inside your large intestine - or colon - and check that everything is okay.

To do this they use an endoscope, which is a long flexible tube with a miniature camera and light at the end.

As they guide the endoscope through the colon a video screen will show the view from the camera. This allows the doctor to inspect the surface of the colon and look for any unusual features.

Photograph of an endoscope
Photograph of an endoscope

How Colonoscopy Works

Your colon is the final section of your digestive system and it is here that any remaining water and nutrients is absorbed from your digested food to produce faeces or stools. The stools are then stored in the last part of your colon, your rectum, until you are able to go to the toilet and excrete them.

Diagram of the intestine
Diagram of the intestine

As they guide the endoscope through the colon a video screen will show the view from the camera. This allows the doctor to inspect the surface of the colon and look for any unusual features.

Colonoscopy uses an endoscope, which is a long flexible tube with a miniature camera and light at the end. Digital cables running through the tube carry video signals from the camera to a TV screen that gives your doctor a full colour view of your colon. Light is fed along the tube using fibre optic cables. Endoscopes also often have built-in instruments that are controlled by wires running through the tube alongside the digital cables and can be used to perform minor surgical operations during the colonoscopy.

During a colonoscopy, the flexible tube of the endoscope is inserted into your colon through your rectum. Perhaps surprisingly, this is uncomfortable rather than painful, but you will be sedated beforehand to minimise any discomfort. The obvious drawback with putting a camera into your colon to see what it looks like, is that it is normally full of partially digested food and faeces! To allow your doctor to see your colon rather than the remains of what you've eaten, you will be put on a diet of clear liquid for a couple of days, followed by a strong laxative just before the colonoscopy.

Once the endoscope has been inserted, your doctor is able to control the camera position and the amount of light as they direct it along your colon. If any suspicious looking areas are found, your doctor will use the built-in instruments to take tissue samples for later analysis.

Colonoscopies are used to look for any evidence of cancer or other diseases in the colon and any tissue samples taken during the procedure are analysed under a microscope. The early detection of diseases, including cancer, greatly increases the effectiveness of treatment.

Colonoscopy Images

Below you will see some still images taken from footage of a colonoscopy, highlighting certain features.

Feature 1

Image from colonoscopy, showing benign diverticulum
Image from colonoscopy, showing benign diverticulum

The small hole you can see is the opening of a diverticulum. This is a small pouch that bulges out through a weak spot in the outer layer of the colon wall, like an inner tube that pokes through a hole in a tire. About half of all people over 50 have diverticula (plural of diverticulum) and in most cases they do not cause any problems.

More info: http://digestive.niddk.nih.gov/ddiseases/pubs/diverticulosis/

Feature 2

Image from colonoscopy, showing a biopsy being taken of the mildly inflamed area
Image from colonoscopy, showing a biopsy being taken of the mildly inflamed area

In this mildly inflamed area the blood vessels are more prominent. Notice the biopsy being taken. A biopsy is where a doctor takes a sample of their patient's tissue sample, which will be sent to a lab for further tests to see if anything is wrong.