[Imaging of colorectal cancer: Role of computed tomography colonography].

Abstract

Background: Computed tomography colonography (CTC) is a minimally invasive examination for radiologic imaging of the entire colon and rectum. It has replaced the now obsolete barium enemas and represents an important option to colonoscopy for the detection of colorectal neoplasia.

Objectives: The aim of this article is to review the current status of CTC for detection of colorectal cancer (CRC) and its precursors.

Materials and methods: Based on an extensive literature research, the current role of CTC in colorectal cancer imaging is summarized. This includes not only CRC detection but also the role of CTC in CRC screening and surveillance.

Results: CTC is a well-developed, minimally invasive examination for the identification of colorectal neoplasia. The diagnostic accuracy for colorectal adenomas and cancer is comparable to that of optical colonoscopy. Missed CRC cases are rare and typically result from perceptual or technical errors. In addition to the detection and characterization of carcinomas, CTC enables the visualization of prestenotic colonic segments and extracolonic structures. This allows for the preoperative detection of synchronous colonic neoplasms that are not endoscopically assessable as well as evaluation of abdominal tumor spread. Due to its ability to detect benign precancerous adenomas with high sensitivity, CTC can be used for opportunistic colorectal cancer screening. In CRC follow-up, CTC may be used to diagnose recurrence if colonoscopy is incomplete or not feasible.

Conclusion: CTC is the radiological examination of choice for the detection of colorectal neoplasia. It is typically used in patients where colonoscopy is incomplete, contraindicated or refused. Moreover, CTC serves as a noninvasive option for opportunistic colorectal cancer screening.