OBJECTIVES:The objective was to determine the availability and quality of computed tomography (CT) and magnetic resonance imaging (MRI) equipment in U.S. emergency departments (EDs). The authors hypothesized that smaller, rural EDs have less availability and lower-quality equipment. METHODS:This was a random selection of 262 (5%) U.S. EDs from the 2005 National Emergency Department Inventories (NEDI)-USA (http://www.emnet-usa.org/). The authors telephoned radiology technicians about the presence of CT and MRI equipment, availability for ED imaging, and number of slices for the available CT scanners. The analysis was stratified by site characteristics. RESULTS:The authors collected data from 260 institutions (99% response). In this random sample of EDs, the median annual patient visit volume was 19,872 (interquartile range = 6,788 to 35,757), 28% (95% confidence interval [CI] = 22% to 33%) were rural, and 27% (95% CI = 21% to 32%) participated in the Critical Access Hospital program. CT scanners were present in 249 (96%) institutions, and of these, 235 (94%) had 24/7 access for ED patients. CT scanner resolution varied: 28% had 1-4 slice, 33% had 5-16 slice, and 39% had a more than 16 slice. On-site MRI was available for 171 (66%) institutions, and mobile MRI for 53 (20%). Smaller, rural, and critical access hospitals had lower CT and MRI availability and less access to higher-resolution CT scanners. CONCLUSIONS:Although access to CT imaging was high (>90%), CT resolution and access to MRI were variable. Based on observed differences, the availability and quality of imaging equipment may vary by ED size and location.