Virtual colonoscopy

For an early detection of a colorectal carcinoma (colon cancer), a haemoccult test (test for occult blood in the stool) as well as a conventional colonoscopy is recommended in Germany. However, since this procedure requires intensive intestinal cleansing and is quite invasive due to the endoscope used, a virtual colonoscopy by means of a CT scan (CT colonography) or an MRI scan (MR colonography) was developed. We offer both procedures in our practice in the highest quality. With Adjunct Prof. Dr. Anno Graser we have a leading specialist in the field of virtual colonoscopy in our team. For many years he has been involved in the development and advancement of this procedure in the course of clinical studies (see literature references below).

Should I consider a virtual colonoscopy? What is involved in this procedure?

Although research findings have shown that a CT colonography in its diagnostic accuracy is equivalent to a conventional colonoscopy, this examination is currently not covered by the health insurance carriers in Germany. The examination costs about 500 € and must be born by the patient. In certain cases, medical contra-indications to a ”conventional” colonoscopy may make insurance coverage possible.

Before the examination, we offer you a personal consultation with one of our practitioners to clarify the indication. A virtual colonoscopy is ideally performed in case of an unsuccessful or aborted conventional colonoscopy or upon the patient’s request for a screening and early detection of colon cancer. Since this type of cancer mostly develops slowly over many years from benign precursor changes, so-called polyps, cancer can often be prevented through early detection and removal of these polyps. A virtual colonoscopy is a safe method to identify such polyps. 92 in 100 asymptomatic adults without any family history of colon cancer will not exhibit any abnormal results or such polyps; for these individuals, a virtual colonoscopy is an ideal and very minimally invasive preventative examination. If your screening reveals polyps of more than 6mm in size, these will have to be removed subsequent to the CT colonography by means of a conventional colonoscopy.

A virtual colonoscopy only requires a very minimal preparation of the colon by administration of a contrast medium to mark the fluid in the colon. Detailed instructions will be given when you register for the procedure. Generally, the preparation begins in the afternoon before the examination day. From 6pm on the day before you can only consume certain beverages and soup, and you will be asked fast on the day of the examination. Immediately after this sedative-free examination and its evaluation, you can continue with your normal daily routine. For this procedure you will only need to be available in the morning hours.

What is involved in this procedure?

A virtual CT colonoscopy is a very quick and minimally invasive examination. On the examination table, the previously cleaned colon is filled and expanded with air or carbon dioxide in order to make it depictable. This is typically not painful. The actual imaging is performed with a state-of-the-art low dose CT scanner, i. e., it only emits a very low amount of ionizing radiation; although the examination requires one scan lying on the back and one on the stomach, the radiation dose is only one fourth of the amount required for a standard CT scan of the stomach and pelvis. The approximately 2000 high resolution images are viewed on a state-of-the-art 3D processing workstation with the diagnosing radiologist taking a virtual 3D tour through your intestines. In addition, by means of highly sophisticated detection algorithms, the computer searches for polyps (precursors of colon cancer) as well. This computer assisted diagnostic procedure in the hands of a specialist has a sensitivity of about 95% in terms of detecting relevant polyps and is with that on par with the conventional colonoscopy.

Conclusion for the practice

Please contact us to see if a virtual colonoscopy may be suitable in your case as an early colon cancer detection approach or if you had an unsuccessful conventional colonoscopy – either by phone (089 / 212196-0) or via email to a.graser@radiologie-muenchen.de. We gladly assist you, and, in case of a correct indication, provide you with the highest quality examination. You will find all necessary technical prerequisites and a highly experienced medical staff at Radiologie München

Literature:

1. Magnetic resonance colonography for the detection of colorectal neoplasia in asymptomatic adults.

Graser A, Melzer A, Lindner E, Nagel D, Herrmann K, Stieber P, Schirra J, Mansmann U, Reiser MF, Göke B, Kolligs FT.
Gastroenterology. 2013 Apr;144(4):743-750.e2. doi: 10.1053/j.gastro.2012.12.041.

2. Comparison of CT colonography, colonoscopy, sigmoidoscopy and faecal occult blood tests for the detection of advanced adenoma in an average risk population.

Graser A, Stieber P, Nagel D, Schäfer C, Horst D, Becker CR, Nikolaou K, Lottes A, Geisbüsch S, Kramer H, Wagner AC, Diepolder H, Schirra J, Roth HJ, Seidel D, Göke B, Reiser MF, Kolligs FT.
Gut. 2009 Feb;58(2):241-8. doi: 10.1136/gut.2008.156448.

Gut. 2009 Feb;58(2):241-8. doi: 10.1136/gut.2008.156448.