Preparation Faecal tagging

Specific CT colonography protocols should be established at a local level and should be based on the currently available published evidence. Protocols should address the method of bowel preparation (clean colon vs fluid or faecal tagging), use or not of intravenous contrast, use or not of spasmolytics, method of colon distension, scanning parameters, and methods of interpretation. The specifics of many of these options are discussed in subsequent chapters. 

The purpose of this chapter is 1) to explain what faecal tagging is 2) to demonstrate why this particular type of preparation is important 3) to explain how faecal tagging is performed at our institution 4) to show imaging findings. 

The rationale of developing a preparation with faecal tagging was twofold 1) improving diagnosis 2) improving patient compliance. 

Faecal residue with a foamy appearance is mostly detected in the cecum or ascending colon. It appears as an amorphous inhomogeneous mixture mostly of air bubbles and stool. They occur in both preparations without and with faecal tagging. In the latter case the foam is tagged or non-tagged. This foam may distract the reader s attention or cover a lesion making detection difficult (Fig 4.19). 

Several studies using a preparation based on faecal tagging have been performed. The results of polyp detection of these studies are listed in Table 4.1. 

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