Lung Imaging Might Not Be Beneficial for Diagnosis of Pulmonary Embolism

Investigators constructed a decision model to determine the most cost-effective diagnostic strategy for pulmonary embolism (PE). They evaluated 60 strategies that differed according to tests used, test order, and values of numerous parameters (e.g., cutoff for a “normal” d-dimer result). The diagnostic tests were d-dimer measurement, lower-extremity compression ultrasonography, computed tomography (CT) pulmonary angiography, and ventilation-perfusion scanning. The analysis relied on numerous assumptions, most importantly that 1.96% of patients tested for PE actually had PE.

The most cost-effective strategy was as follows: (1) Categorize risk using Wells score modified by whether deep venous thrombosis is clinically evident; (2) measure d-dim…