PURPOSE: Pulmonary embolism (PE) is a common and sometimes fatal disease. Diagnosis can be challenging because the signs and symptoms are nonspecific. Computed tomographic pulmonary angiography (CTPA) is more sensitive and specific than ventilation-perfusion (V/Q) scanning for the diagnosis of pulmonary embolism (PE). However, little is known about factors influencing the choice of a diagnostic test. We compared the use of V/Q scanning and CTPA for the diagnosis of PE over the past 5 years.
METHODS: Retrospective review of the medical records in a tertiary care, academic, medical center.
RESULTS: In the year 2000, 87 CTPA tests were ordered, compared to 1115 in year 2005, representing a 13 fold increase. Interestingly, the number of V/Q scans also increased from year 2000 (574) to 2005 (734) –a 1.2 fold increase. However, the number of CTPA tests positive for a PE in the year 2000 was 19 (of 87 ordered) and 162 (of 1115 ordered) in 2005. This means that the diagnostic yield of CTPA fell from 21% to 14.5% from year 2000 to 2005.
CONCLUSION: Our results indicate that though an increasing number of CTPA procedures are being performed, the number of positive tests has decreased. Moreover, CTPA does not appear to be replacing V/Q scanning.
CLINICAL IMPLICATIONS: Increase in the total number of tests ordered without a proportionate increase in yield could reflect the lack of use of an appropriate diagnostic algorithm. We are currently reviewing the medical records to determine indications used by physicians for pursuing the diagnosis of PE and factors determining their choice of diagnostic study.
DISCLOSURE: Subani Chandra, No Financial Disclosure Information; No Product/Research Disclosure Information