Utilization of CT scans appears to have peaked and has decreased during the last two years, based on the EDBA data surveys over the last 10 years (see Table 2). CT utilization peaked at 22 CT scans per 100 patients seen between 2006 and 2011. There was a 10 percent drop in utilization to 20 CT procedures per 100 patients seen in 2012 and 2013. This is consistent with a recent report that showed decreased growth in CT and MRI imaging rates over the last nine years.1
There is about a 50 percent difference in CT utilization based on ED volume, with the range between 16 and 24 procedures per 100 patients seen. Pediatric EDs only use CT imaging about four times per 100 patients seen. Plain diagnostic X-rays show little difference in utilization based on volume.
According to the EDBA report, MRI utilization across all EDs has now reached about 1.3 procedures per 100 patients seen, but this increases to 1.9 in the high-level trauma centers.
Trauma centers utilize diagnostic imaging to evaluate patients with critical injuries. Within the EDBA data set, the data have been sorted into separate cohorts of trauma centers (see Table 3). Pediatric trauma centers have very different profiles than general EDs, so they are excluded. The three cohorts are Level I and II trauma centers, Level III and IV trauma centers, and all other EDs.
Table 3 shows that the higher-level centers see patient populations with higher acuity, admission rates, emergency medical services (EMS) arrival, and longer time for processing. There are also differences in the use of diagnostics commensurate with the trauma level.
CT scans are used more frequently in Level I and II trauma centers than in lower-level centers. There are 26 CT procedures per 100 patients seen in Level I and II trauma centers and 18 to 20 procedures in lower-level and nontrauma centers. Emergency physicians in these EDs should be aware of the differences, and when called upon to study their utilization, they should compare their experience to cohorts at a similar level of trauma designation and pediatric mix.