CT pulmonary angiography: a comparative analysis of the utilization patterns in emergency department and hospitalized patients between 1998 and 2003.

OBJECTIVE: The purpose of our study was to objectively examine the temporal utilization patterns of CT pulmonary angiography in emergency department and hospitalized patients in an academic tertiary care center.

SUBJECTS AND METHODS: Patients who underwent CT examination for suspected pulmonary embolism either through our emergency department or as inpatients during a recent 9-month interval were identified. The absolute number of studies and incidence of positive results and ancillary findings were compared with similar data published from our institution during the corresponding 9-month interval in 1997-1998.

RESULTS: The overall number of patients imaged for pulmonary embolism was significantly greater in the 2002-2003 period than in the 1997-1998 period (homogeneity of rates = 88.45, p < 0.0001). The absolute number of scans obtained was significantly greater in both the emergency department (chi(2) = 167.03, p < 0.0001) and inpatient (chi(2) = 210.62, p < 0.0001) groups in the more recent population. Significantly fewer ancillary findings were reported in both the emergency department (chi(2) = 5.93, p = 0.019) and inpatient (chi(2) = 6.03, p = 0.015) groups in the more recent population. The incidence of CT-detected pulmonary embolism was significantly less in both the emergency department (chi(2) = 34.26, p < 0.0001) and inpatient (chi(2) = 8.52, p < 0.01) groups in the more recent population. This decrease in the incidence of scans with positive findings for pulmonary embolism over time was significantly greater in the emergency department group than the inpatient group (homogeneity of odds = 0.003, p < 0.007).

CONCLUSION: The evolution of CT pulmonary angiography utilization has led to a significant increase in the number of patients being imaged for pulmonary embolism with a coincident significant decrease in the rates of CT-detected pulmonary embolism and ancillary findings both in emergency department and hospitalized patients.