CT colonography: avoiding traps and pitfalls

Philippe Lefere,Stefaan Gryspeerdt

doi:10.1007/s13244-010-0054-3

Abstract

Computed tomographic colonography (CTC) is a reliable technique for detecting tumoral lesions in the colon. However, good performance of polyp detection is only achieved if experienced CTC radiologists combine meticulous interpretation with state-of-the-art CTC technique. To reach this experience level, CTC training is mandatory. With a considerably long and steep learning curve, it has been demonstrated that in inexperienced hands both technical failure and observer errors stand for the majority of missed lesions. The purpose of this pictorial review is to give an overview of traps and pitfalls in CTC imaging resulting in false negative and positive findings, and how to avoid them by application of state-of-the-art CTC technique and interpretation.

Highlights

Computed tomographic colonography (CTC) is a reliable technique for detecting tumoral lesions in the colon [1,2,3,4]
Good performance in polyp detection is only achieved if experienced CTC radiologists combine meticulous interpretation with state-of-the-art CTC technique [5]
Together with preparation combining a low residue diet with laxatives or cathartics, faecal tagging is an essential part of this process [9]

Summary

Introduction

Computed tomographic colonography (CTC) is a reliable technique for detecting tumoral lesions in the colon [1,2,3,4]. In some cases a low dose causes excess image noise resulting in pseudo-enhancement: an artificial increase in the tissue density sometimes resulting in pseudo-tagging, i.e. making a true lesion look like tagged stool (Fig. 6) [12]. This problem can be solved by comparing the lesion with tagged stool elsewhere in the colon or by smoothing the abdominal window.

Results

Conclusion