Patient radiation safety in imaging in Crohn’s disease

Crohn's disease (CD) is a chronic inflammatory bowel disease that affects the entire gastrointestinal (GI) tract from the mouth to anus and has an estimated incidence of up to 20 cases per 100 000. It is a chronic remitting disease associated with significant morbidity and increasing incidence worldwide. While endoscopy and biopsy form the cornerstone of diagnosis, cross-sectional imaging modalities such as ultrasound (US), CT, and MRI play a pivotal role in assessing disease extent and treatment response. Luminal complications such as stenoses, strictures, and complications such as fistula and abscesses are accurately detected and characterized non-invasively with these modalities. The appropriate use of imaging in CD, therefore, facilitates identification and localization of diseased bowel segments and detection of complications and associations such as sclerosing cholangitis and sacroiliitis. Due to undisputed value of cross-sectional imaging combined with the chronic remitting and relapsing nature of CD, patients often undergo large numbers of imaging studies throughout their lifetime for diagnostic and surveillance purposes. This includes plain radiography and CT scanning, both of which involve exposure to ionizing radiation. While the diagnostic information obtained from imaging is crucial for appropriate patient management, over a lifetime, patients with CD may be cumulatively exposed to high levels of ionizing radiation. Therefore, consideration of patient radiation safety is of great importance and should form part of the risk-benefit analysis preceding each imaging study in CD patients. Given the increasing incidence of Crohn's disease, and the development and optimization of alternative imaging modalities in CD, which avoid radiation exposure, as well as the sustained advances in CT technology which facilitate radiation dose reduction, the preparation of this article is timely. This article aims to deliver an up-to-date overview of the role of imaging in Crohn's disease and how consideration of radiation safety and radiation dose optimization impacts choice of imaging modality in CD.