Can multislice CT alone rule out reliably pulmonary embolism? A prospective study

Purpose: To evaluate the safety of withholding anticoagulation in patients with suspected acute pulmonary embolism after negative multislice computed tomography (MSCT) pulmonary angiography and lower-limb venography. Materials and methods: A total of 383 consecutive patients with suspected acute pulmonary embolism were prospectively studied. Patients underwent NISCT pulmonary angiography and lower-limb venography, as well as pulmonary scintigraphy and lower-limb ultrasound examination. Patients with negative NISCT results for both pulmonary embolism and venous thrombosis were not administered anticoagulants and were followed up for 6 months to rule out thromboembolism. Results: At NISCT, 156 patients were positive for pulmonary embolism, venous thrombosis, or both; 224 were negative; and findings were inconclusive in three. False-negatives were five patients with high probability scintigram and two with venous thrombosis detected at US. A total of 184 patients with negative NISCT and without anticoagulation were followed up for 6 months. During this period of time just one recurrence of pulmonary embolism was detected. The negative predictive value of MSCT pulmonary angiography plus lower-limb venography was 95.8% (183/191). Conclusion: NISCT is efficacious in diagnosing pulmonary embolism, with negative predictive values reported in the literature ranging from 94% to 100%. This enables omission of anticoagulation in patients with suspected pulmonary embolism after negative NISCT findings without the need for other diagnostic tests. (c) 2006 Elsevier Ireland Ltd. All rights reserved.