Temporal trends in imaging and associated radiation exposure in inflammatory bowel disease

Increasing use of diagnostic imaging in inflammatory bowel disease (IBD) has led to concerns about the malignant potential of ionising radiation in a cohort that have an increased lifetime risk of gastrointestinal malignancy. The aim was to quantify radiation exposure in IBD patients referred from primary care, determine predictors of high exposure and evaluate temporal trends in diagnostic imaging over a 20-year period.

This was a retrospective cohort study whereby IBD patients were recruited from the outpatient clinic and evaluated retrospectively. The total cumulative effective dose (CED) received from tests was calculated for each subject. Cox regression was performed to assess factors associated with potentially harmful levels of ionising radiation defined as total CED > 50 milli-sieverts (mSv; equivalent to five CT abdomen scans).

The cohort included 415 patients. Median total CED was 7.2 mSv (IQR: 3.0-22.7) in Crohn's disease and 2.8 mSv (IQR: 0.8-8.9) in ulcerative colitis patients, respectively. A total of 32 patients (8%) received a CED > 50 mSv. A history of IBD-related surgery was associated with high exposure (HR 7.7). During the study period, usage of abdominal CT increased by 310%.

Approximately 1 in 13 patients in the study cohort were exposed to potentially harmful levels of ionising radiation. Strategies to minimise exposure to diagnostic medical radiation in IBD patients are required.