Impact of spiral computed tomography on the diagnosis of pulmonary embolism in a community hospital setting

Background: While the optimal role of spiral CT angiography (CTA) in the diagnosis of pulmonary embolism (PE) remains controversial, this technology is already being widely utilized in the community setting. Objectives: To assess the impact CTA has had on angiography utilization rates and the overall diagnostic rate of PE. Methods: All patients evaluated for PE during a 4-year period were studied. PE was defined as either a high-probability V/Q scan, a positive conventional angiogram, or a CTA with emboli in the segmental or larger pulmonary vessels. Diagnostic rates of PE per 1,000 hospital admissions were determined and analyzed for time periods before and after the introduction of CTA. CT reports were compared with their concurrent chest radiograph (CXR) reports and additional findings that were not apparent on CXR were abstracted. Results: The diagnostic rate of PE per 1,000 hospital admissions was 1.8 prior to the introduction of CTA and increased to 2.8 per 1,000 admissions after the introduction of CTA (p < 0.0001). Total costs for diagnostic testing per PE diagnosis made went from $2,518 to $2,572. While the number of PE diagnosed by V/Q scan remained constant, the number of PE diagnosed by conventional angiography decreased while the number diagnosed by CTA increased. In patients with intermediate probability V/Q scan results, the percentage of patients receiving subsequent angiography (conventional or CTA) increased from 17 to 26% (p = 0.043). When conventional angiography was performed, CT imaging of the chest still had to be ordered for other reasons 38% of the time. Additional information was obtained in 78% of cases when CTA was performed. Conclusions: Increased utilization of CTA was associated with an increase in angiography utilization rates and diagnostic rates of PE, was cost effective, and often provided additional, useful, and unanticipated diagnostic information.