Risk of pulmonary embolism after a negative spiral CT angiogram in patients with pulmonary disease: 1-year clinical follow-up study.

Purpose: To evaluate the effect of pulmonary disease on diagnostic utility of spiral computed tomographic (CT) angiography in clinical practice.

Materials And Methods: Three hundred thirty-four patients, including 215 patients with pulmonary disease (group 1) and 119 patients with no history of respiratory disorder (group 2), were referred for thin-collimation CT angiography of the pulmonary circulation as the first-line diagnostic test. Patients with negative angiograms who had not received anticoagulation therapy and who could be clinically followed up at 3 months, 6 months, and 1 year were considered in the final study groups (n = 185); 135 patients had lung disease (group 3), and 50 patients had no history of a respiratory disorder (group 4).