Diagnosis of Pulmonary Embolism by Multidetector CT Alone or Combined With Venous Ultrasonography of the Leg - Diagnosis of PE by MSCT Alone or Combined With Venous Ultrasonography of the Leg


The goal of the trial was to evaluate outcomes after evaluation for pulmonary embolus with D-dimer, multidetector computed tomography (CT), and lower extremity ultrasound compared with D-dimer and multidetector CT.


A strategy of D-dimer and multidetector CT will be noninferior in the diagnosis of pulmonary embolus.

Study Design

Study Design:

Patients Screened: 2,864
Patients Enrolled: 1,812
Mean Follow Up: 3 months
Mean Patient Age: 59 years
Female: 55

Patient Populations:

Patients ≥18 years of age, with suspected pulmonary embolus


• Allergy to contrast dye
• Renal insufficiency
• Pregnancy
• Diagnosis of pulmonary embolus established and anticoagulation therapy initiated
• Patients unavailable or unwilling for follow-up

Primary Endpoints:

Change in proportion of venous thromboembolic events diagnosed 3 months after randomization

Secondary Endpoints:

Change in mortality

Drug/Procedures Used:

Patients with suspected pulmonary embolus, as assessed by the revised Geneva score, were randomized to D-dimer, CT, and lower extremity ultrasound (n = 916) or D-dimer and CT (n = 903). High-risk patients in either group could proceed to ventilation perfusion scintigraphy or pulmonary angiogram if initial testing was negative.

Concomitant Medications:

Patients were anticoagulated if diagnostic tests revealed evidence of pulmonary embolus.

Principal Findings:

The overall prevalence of pulmonary embolus was 21% in both groups. In the remaining patients who were not diagnosed with pulmonary embolus, the incidence of the primary outcome, venous thromboembolic events at 3 months of follow-up, was 0.3% in the D-dimer, ultrasound, and CT group, and 0.3% in the D-dimer and CT group (p > 0.99). There was no difference in the incidence of the primary outcome when the results were analyzed by intention-to-diagnosis or per-protocol analysis.

During follow-up, in the D-dimer, ultrasound, and CT group, there were 37 deaths (14 after confirmed pulmonary embolus), and in the D-dimer and CT group, there were 22 deaths (7 after confirmed pulmonary embolus).


Among patients with suspected pulmonary embolus, evaluation with D-dimer and multidetector CT was safe and noninferior to D-dimer, multidetector CT, and lower extremity ultrasound. Both strategies led to the diagnosis of pulmonary embolus in 21% of cases. The diagnosis of venous thromboembolic events in the 3 months after evaluation was similar, at 0.3% in both groups.

The use of lower extremity ultrasound may not be necessary for all patients, except those with a contraindication to multidetector CT (for example, renal insufficiency) or high probability for pulmonary embolus in spite of initial negative testing.


Righini M, Le Gal G, Aujesky D, et al. Diagnosis of pulmonary embolism by multidetector CT alone or combined with venous ultrasonography of the leg: a randomized non-inferiority trial. Lancet 2008;371:1343-52.

Clinical Topics: Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Vascular Medicine, Interventions and Imaging, Interventions and Vascular Medicine, Computed Tomography, Nuclear Imaging

Keywords: Prevalence, Renal Insufficiency, Follow-Up Studies, Fibrin Fibrinogen Degradation Products, Pulmonary Embolism, Multidetector Computed Tomography, Probability, Perfusion Imaging

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