Trends in Utilization Rates of the Various Imaging Modalities in Emergency Departments: Nationwide Medicare Data From 2000 to 2008

Purpose: To study utilization trends in the various imaging modalities in emergency departments (EDs) over a recent multiyear period. Methods: The nationwide Medicare Part B databases for 2000 to 2008 were queried. Medicare's location codes were used to identify imaging examinations done on ED patients. All diagnostic imaging Current Procedural Terminology (R) codes were grouped by modality. For each code, the database provides procedure volume; utilization rates per 1,000 beneficiaries were then calculated. Medicare's physician specialty codes were used to determine provider specialty. Utilization trends were studied between 2000 and 2008. Results: The overall utilization rate per 1,000 beneficiaries for all imaging in EDs increased from 281.0 in 2000 to 450.4 in 2008 (+60%). The radiography utilization rate rose from 227.3 in 2000 to 294.3 in 2008 (+29%, 67 accrued new studies per 1,000). The CT rate rose from 40.0 in 2000 to 130.7 in 2008 (+227%, 90.7 accrued new studies per 1,000). The ultrasound rate rose from 9.6 in 2000 to 18.7 in 2008 (+95%, 9.1 accrued new studies per 1,000). Other modalities had much lower utilization. In 2000, CT constituted 14% of all ED imaging, but by 2008, it constituted 29%. In 2008, radiologists performed 96% of all ED imaging examinations. Conclusions: The rate of utilization of imaging is increasing in EDs. Growth is by far the most pronounced in CT, in terms of both the growth rate itself and the actual number of accrued new studies per 1,000 beneficiaries. Radiologists strongly predominate as the physicians of record for all ED imaging.