In the era of multislice CT, do we still need leg ultrasonography to diagnose pulmonary embolism?

Overview

The results of a multicenter, randomized, prospective, noninferiority trial by Righini et al., together with the low prevalence of a positive CT venography (CTV) scan alone shown by many other investigators, indicate that leg studies after multislice CT angiography for thromboembolism are redundant. The proportion of diagnoses that are made on the basis of a positive CTV scan in patients with a negative multislice CT angiography scan, however, is 14% on average. The diagnostic yield of CTV and of compression ultrasound could be increased by their select use in patients who are likely to have deep-vein thrombosis. Radiation exposure from CTV can be reduced by eliminating imaging of the pelvic veins and by obtaining discontinuous axial images of the proximal leg veins. There are several valid reasons for recommending or not recommending leg studies in patients with suspected pulmonary embolism, and the choice of diagnostic tests should be individualized on a patient-by-patient basis.