Background Displaying radiation exposure and cost information at electronic order entry may encourage clinicians to consider the value of diagnostic imaging.

Methods An urban safety-net health system displayed radiation exposure information for CT and cost information for CT, MRI and ultrasound on an electronic referral system for outpatient ordering. We assessed whether there were differences in numbers of outpatient CT scans and MRIs per month relative to ultrasounds before and after the intervention, and evaluated primary care clinicians’ responses to the intervention.

Results There were 23 171 outpatient CTs, 15 052 MRIs and 43 266 ultrasounds from 2011 to 2014. The ratio of CTs to ultrasounds decreased by 15% (95% CI 9% to 21%), from 58.2 to 49.6 CTs per 100 ultrasounds; the ratio of MRIs to ultrasounds declined by 13% (95% CI 7% to 19%), from 37.5 to 32.5 per 100. Of 300 invited, 190 (63%) completed the web-based survey in 17 clinics. 154 (81%) noticed the radiation exposure information and 158 (83.2%) noticed the cost information. Clinicians believed radiation exposure information was more influential than cost information: when unsure clinically about ordering a test (radiation=69.7%; cost=46.4%), when a patient wanted a test not clinically indicated (radiation=77.5%; cost=54.8%), when they had a choice between imaging modalities (radiation=77.9%; cost=66.6%), in patient care discussions (radiation=71.9%; cost=43.2%) and in trainee discussions (radiation=56.5%; cost=53.7%). Resident physicians and nurse practitioners were more likely to report that the cost information influenced them (p<0.05).

Conclusions Displaying radiation exposure and cost information at order entry may improve clinician awareness about diagnostic imaging safety risks and costs. More clinicians reported the radiation information influenced their clinical practice.