Computed tomography utilization rates after the placement of a scanner in an emergency department: a single-center...

The convenience of a computed tomography (CT) scanner in the emergency department (ED) may impact utilization rates. Our primary aim was to determine the rate of utilization before and after the placement of an ED CT scanner. Secondary aims were to determine the rate of utilization by anatomic region and during a 5-month period when the ED scanner was unavailable. We performed an electronic chart review of our ED with an annual census of 70,000 patients. We identified all patients over the age of 21 who had a CT scan performed from January 2008 to October 2010. Predetermined data elements were extracted by trained, hypothesis-blinded abstractors. Comparisons overall and within scan subtype were performed using seasonal matching. We found a CT utilization rate of 114 per 1,000 patient visits before and 139 per 1,000 patient visits after the placement of a CT scanner in the ED (p<0.0001). Linear regression analysis found a line with a slope of β=0.114 (95 % CI=0.107-0.121) and an R2 of 0.508. CT rates increased in the following regions: head CTs by 14 per 1,000 visits (p<0.0001); neck CTs by 3 per 1,000 visits (p<0.0001); abdomen/pelvis CTs by 4 per 1,000 visits (p=0.0015); "other" CTs by 2 per 1,000 visits (p<0.0001). Increased rates of chest and facial CTs approached significance with p values of 0.05. During the 5-month downtime, utilization remained unchanged at 141 per 1,000 visits (p=0.38). Overall CT utilization increased after the placement of a scanner in the ED. Most subtypes of scan increased. Utilization was unchanged during a period of ED scanner unavailability, suggesting that increased utilization may be difficult to reverse.