CT Angiography Is More Likely to Be Negative for PE When Ordered for Defensive Reasons

Researchers assessed physicians' reasons for ordering computed tomography pulmonary angiography (CTPA) at a single emergency department in Switzerland during a one-year period (328 CTPAs; 19.2% positive). Physicians received training on estimating pretest probability with the standardized Wells/Geneva score and were asked to calculate a Wells/Geneva score and complete a questionnaire about reasons for ordering CTPA, before ordering the test.

Physicians completed the questionnaire in 43 of cases and calculated the Wells/Geneva score in 53%. The incidence of pulmonary embolism (PE) was 19% overall and was significantly higher in cases with completed questionnaires than in those without (26% vs. 14%). The most common reasons for ordering CTPA w…