Radiology utilization in the emergency department: trends of the past 2 decades

The objective of our study was to assess radiology utilization trends for emergency department (ED) patients from 1993 through 2012.

For this retrospective study, we reviewed radiology utilization at a 793-bed quaternary care academic medical center from January 1, 1993, through December 31, 2012, during which time the number of ED patient visits increased from approximately 48,000 to 61,000, and determined the number of imaging studies by modality (radiography, sonography, CT, MRI, other) and associated relative value units (RVUs). We used linear regression to assess for trends in the number of imaging RVUs and imaging accession numbers, our primary and secondary outcomes, respectively.

The total RVUs attributable to ED imaging per 1000 ED visits increased 208% from 1993 to 2007 (p < 0.0001) and then decreased 24.7% by 2012 (p = 0.0019). The total number of imaging accession numbers per 1000 ED visits increased 47.8% from 1993 until 2005 (p = 0.0003) and then decreased 26.9% by 2012 (p < 0.0001). CT RVUs per 1000 ED visits increased 493% until 2007 (p < 0.0001) and then decreased 33.4% (p < 0.0001), and MRI RVUs increased 2475% until 2008 (p < 0.0001) and then decreased 20.6% (p < 0.0032). Sonography RVUs increased 75.7% over the study period (p < 0.0001), whereas radiography RVUs decreased 28.1% (p = 0.0009).

After a period of substantial increase from 1993 to 2007, volume-adjusted ED imaging RVUs declined from 2007 through 2012, largely because of the decreasing use of CT and MRI. Additional studies are needed to determine the causes of this decline, which may include quality improvement activities, advocacy for appropriateness by leadership, concerns regarding radiation exposure and cost, and health information technology interventions.