Gregory D. N. Pearson MD, PhD, Presenter: Consultant, General Electric Company

Michal Edward Kulon MD, Abstract Co-Author: Nothing to Disclose

Anna Rozenshtein MD, Abstract Co-Author: Nothing to Disclose

Robert A Green MD, Abstract Co-Author: Nothing to Disclose

Stephen Chang MD, Abstract Co-Author: Nothing to Disclose

Neil W Schluger MD, Abstract Co-Author: Nothing to Disclose

Andrew Einstein MD, Abstract Co-Author: Nothing to Disclose

To examine utilization patterns and percent positivity (PP) of pulmonary CT angiography (CTPA) for workup of pulmonary emboli in the emergency department (ED).

We collected data on age, ethnicity, gender, CTPA and D-dimer assay results, time, date, ordering and interpreting MDs in patients age 18 or older who underwent a CTPA in the ED between 4/1/2003 and 11/30/2009. Statistical analysis was performed using Fisher's exact test and linear regression with 95% confidence intervals (CI) using Binomial or Poisson distributions.

Total 4692 patients had 9% positive, 89.5% negative, and 1.6 % indeterminate studies. Utilization increased from 8.6 scans/1000 visits in 2004 to 13.0 scans/1000 visits in 2009 while PP showed an insignificant downward trend (range 7.5% - 12.6%, decrease 0.56%/year, R2=0.46, P=0.096, 95% CI -1.25% to +0.14%). There was no change over the study period in PP by D-Dimer result (mean PP 10.9%, 1.6%, and 9.4% in positive, negative, and none categories), days of the week and time of day. PP was lower in Hispanics (7.3%, P<0.02, N=1307) than in Caucasians (10.2%, N=744) and African Americans (11%, N=1008), higher in men (10%, N=1590, P=0.042) than in women (8.4%, N=3101), and higher in the elderly (>65 years of age, 11.4%, N=1503, P<0.002) than in patients 40-65 (8.3%, N=1907) and 18-39 (7%, N=1282) years of age. Variation in PP among radiologists (7.7-9.7%) was not significant. PP among ED physicians ranged from 1.7 to 10.5%, with the lowest PP significantly different from mean (P=0.0012). More scans were performed on Wednesdays and fewer on Mondays, without change in PP.

While use of CTPA as the diagnostic modality for pulmonary embolus increased over the last six years, PP remained stable. There was significant variability in PP among referring physicians. Hispanics were found to have significantly lower and the elderly significantly higher PPs.

Percent positivity of CTPA in the ED between 2004 and 2009 remained stable despite increased utilization.

Pearson, G, Kulon, M, Rozenshtein, A, Green, R, Chang, S, Schluger, N, Einstein, A, Utilization and Positivity Rates of CT Angiography for Pulmonary Emboli in the Emergency Department.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11011409.html