Diagnostic imaging trends in the emergency department: an extensive single-center experience

BACKGROUND: Emergency Department imaging volume has increased significantly in North America and Asia. PURPOSE: To assess Emergency Department imaging trends in a European center. MATERIAL AND METHODS: The institutional radiological information system was queried for all computed tomography (CT), ultrasound (US), and magnetic resonance (MR) studies performed for the Emergency Department during 2002–2017. Descriptive statistics and linear regression analyses were used to assess overall study rates and temporal trends in overall and after-hours imaging after adjusting for patient visitations. RESULTS: CT use increased significantly from 38/1000 visits to 108/1000 at the end of the observation by 5.5 new exams per 1000 visits/year (P < 0.0001). US use increased gradually at a rate of 1.2/1000 per year during 2002–2008 with an accelerated annual increase of 6.4/1000 in 2009–2011 (P < 0.0001) raising US rates from 7/1000 to 28/1000 visits per year with stable rates from 2012 onwards. After on-site MR became available in 2004, its use increased from 0.3/1000 to 7/1000 at a rate of 1.9/1000 visits per year in 2005–2009 (P < 0.0001) and remained stable from 2010. While there was a significant increase in after-hours imaging, growth remained proportional to the overall trend in the use of CT, MR, and night-time CT with the exception of a slight decrease in after-hour US in favor of standard working hours (P < 0.0001). CONCLUSION: All modalities increased significantly in volume adjusted usage. US and MR rates have been stable since 2012 and 2010, respectively, after periods of increase while CT use continues to increase. Demand for after-hours imaging was mostly proportional to the overall trend.