Purpose:To determine the effect of evidence-based clinical decision support (CDS) on the use and yield of computed tomographic (CT) pulmonary angiography for acute pulmonary embolism (PE) in the emergency department (ED).

While ICU health care workers consistently identify a number of patient factors as important in decisions to withdraw care, there is extreme variability, which may be explained in part by the values of individual health care providers.

Objective To assess radiology utilization trends for emergency department (ED) patients from 1993 through 2012. Methods In this institutional review board-approved, retrospective study at a 793-bed tertiary care academic medical center, we reviewed radiology utilization from January 1, 1993 through December 31, 2012, during which time the number of ED patient visits increased from 48,000 to 61,000, and determined the number of imaging studies by modality (x-ray, 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. Results The total RVUs attributable to ED imaging per thousand ED visits increased 208% from 1993–2007 (p<0.0001) and then decreased 24.7% by 2012 (p<0.0019). The total number of imaging accession numbers per thousand ED visits increased 47.8%from 1993 until 2005(p=0.0003), then decreased 26.9% by 2012 (p<0.0001). CT RVUs per thousand ED visits increased 493% until 2007 (p<0.0001) and then decreased 33% (p<0.0001), MRI RVUs increased 2,475% until 2008 (p<0.0001) and then decreased 20.7% (p<0.032). Ultrasound RVUs increased 75.7% over the study period (p<0.0001) while x-ray RVUs decreased 28.1% (p=0.0009). Conclusions Following a period of substantial increase from 1993–2007, volume-adjusted ED imaging RVUs declined from 2007–2012, largely due to decreasing use of CT and MRI. Further 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 IT interventions.

Implementation of quarterly feedback reporting resulted in a modest but significant increase in adherence to evidence-based guidelines for use of CT for evaluation of PE in ED patients, enhancing the impact of CDS alone. These results suggest potentially synergistic effects of traditional performance improvement tools with CDS to improve guideline adherence.