P278 Radiation exposure in patients with inflammatory bowel disease

Abstract

Abstract Background Radiological imaging plays an important role in diagnosis and follow-up of patients with IBD. Due to the progressive character of the disease, repeated imaging may be necessary. A cumulative effective dose (CED), meaning the total diagnostic radiation received, of 75 mSv is often described as the risk level one needs to try not to exceed. However, data on cumulative exposure are limited in IBD. In this retrospective study, we analysed the cumulative radiation exposure of patients with IBD in a Belgian tertiary referral centre. Methods Electronic health records (EHRs) from all IBD patients followed at the tertiary referral centre between January 1st 1990 and December 31st 2021 were searched for examinations with radiation exposure and received doses in house or in any of 27 collaborating Nexuz hospitals working with the same EHR. Both the annual effective dose (AED) and CED were calculated. A sub-analysis of patients diagnosed after January 1st 2007 was performed, as detailed radiation doses were maintained prospectively from that date onwards. Results In total, 3429 IBD patients were included. The median (IQR) AED was 0.39 (0.01-1.66) mSv/year, and was higher in patients with CD than in patients with UC [0.58 (0.01-1.81) vs. 0.17 (0.01- 1.24) mSv/year, p=0.028]. During the first 20 years after diagnosis, the received CED were found higher in patients with CD than UC (Figure, p<0.01). In 5.5% of patients, a CED ≥75 mSv was reached after a median (IQR) of 24 (13-34) years of follow-up. Sub-analysis of 1633 patients diagnosed after January 1st 2007 showed a median (IQR) AED of 0.44 (0.01- 2.12) mSv/year, again higher in patients with CD than in patients with UC [0.82 (0.02-2.38) mSv/year vs. 0.12 (0.01-1.47) mSv/year respectively, p=0.040]. Here, 3.3% patients reached a CED ≥75 mSv during a median (IQR) of 9 (6-12) years of follow-up. Most common reasons for high radiation exposure were comorbidities like malignancy and postoperative complications. Chart review by an IBD expert showed that the indication for most of these examinations was appropriate and that no alternative examination was available in a timely manner. Conclusion Up to 5.5% of patients with IBD were exposed to a CED of ≥75 mSv. Although most decisions to perform imaging with radiation exposure were appropriate, vigilance for unconsidered and excessive imaging should be maintained.