Incidental findings in volunteer imaging used to develop radiotherapy MRI workflows

Introduction/Background: Healthy volunteer imaging is integral to optimising sequences for use in a treatment planning pathway to ensure they are fit for purpose. Although initial imaging may not be optimal quality, it may still be possible to identify abnormalities. Methods: All healthy volunteer participants recruited to approved studies aimed at optimising MRI sequences for use in radiotherapy at our institution were included. Participants were imaged on either an MR Sim (Philips Ingenia, Best, Netherlands) or MR Linac system (Unity, Elekta, Sweden), or both and each imaging time point was analysed separately. Results: 145 participants underwent 258 imaging sessions. Incidental findings were identified in 31 (21.3 %) participants. 96 participants were female and median age 29 years (range 22–59). Imaging was reviewed by one of four radiologists and findings categorised in terms of clinical significance. In eleven cases, onward referral was recommended: Three defined as potentially serious. Seven had a documented consultation informing participants of report findings, and actions taken. Positive predictive value was 45 % and negative predictive value 100 %. There was no difference in number of findings between imaging system (p = 0.15). Discussion: Rate of incidental findings compares favourably with the literature. This rate cannot be ignored, and radiotherapy services should be aware of the need to develop, and audit, procedures that appropriately manage findings. Conclusion: MRI scanners are not routinely managed by radiotherapy services. Potentially significant findings are seen in around 4 % of healthy volunteers and the procedures around managing findings may be new to radiotherapy services.