How CTC and traditional colonoscopy are performed
In CT colonoscopy, helical CT or MRI is used for the purpose of imaging. It usually consists of preparing the patients, distension of the colon, a multi detector scanning and an interpretation that uses a CTC software that gives 3D images. The preparation and examination on the patient is done using various ways and protocols. The most important part is a one day preparation of colon where the patient is given instruction on clearing their bowels. CTC also involves distension of the whole colon, which is done with an automated Carbon dioxide insufflator by way of inserting a small catheter tipped with balloon. A technique of a thin collimation is employed on the scanner with a little dose of radiation. Image is acquired on holding ones breath to limit effects of pressure arising from inflated lungs (Patel & Chang, 2016, p.3). The traditional colonoscopy utilises a wet preparation of high volume solution such as polyethylene. It involves sedation where the patient is given medication, normally through IV line that will help them relax and be comfortable. A scope is then guided through the anus to the colon and images are taken.
Image analysis
The effectiveness of image analysis in CT colonography and conventional colonoscopy depends on the experience and the training of the user of the data. An image analysis on primary 3D is comparable to an analysis on primary 2D in terms of detecting the lesions when the analysis is done by an inexperienced reader. As per studies done, detection of tiny lesions was low for all the readers in spite of the advanced equipment used. This is more so where bowel cleansing and distension are not properly done. Moreover a complete analysis in 3D and 2D consumes a lot of time since the results have to be checked by the aid of experienced radiologists or checked against results obtained from traditional colonoscopy or surgery. However, with advanced modern software and medical systems being used by experienced medics, image analysis can be done within 10 minutes time (Fisichella, 2009 p.78). The results of CTC image analysis do not differ from the results of conventional colonoscopy image analysis if performed by experienced readers. The data can be analysed by at least two radiologists independently with no knowledge of the patient’s clinical data nor results of the other imaging or screening. The differences in opinion about CTC and traditional results can then be resolved through a consensus (Ayman et. al, 2013, pg. 4)
