Clinical outcomes of patients after a negative spiral CT pulmonary arteriogram in the evaluation of acute pulmonary embolism

PURPOSE: To examine 6-month clinical outcomes of patients after acquisition of a spiral computed tomography (CT) pulmonary arteriogram interpreted as negative for acute pulmonary embolism (PE). MATERIALS AND METHODS: A retrospective review was performed on a consecutive series of 143 patients who underwent spiral CT pulmonary arteriography for possible acute PE during a 19-month period, All studies were performed on a HiSpeed Scanner with use of 3-mm collimation with a pitch between 1.3 and 2.0, depending on patient size. All imaging was performed during dynamic contrast material injection at rates between 3.0 and 4.0 mL/sec, timed to peak pulmonary arterial enhancement, For the studies interpreted as negative for PE through the segmental (fourth order) pulmonary arteries, follow-up data were collected by telephone interviews with patients or surviving relatives, and by medical record reviews. RESULTS: Among 143 patients, 22 studies (15%) were positive for PE, eight (6%) were suboptimal to exclude PE to the segmental artery level, and 113 (79%) were interpreted as negative for acute PE, Among the 113 negative studies, 13 patients were lost to follow-up, leaving a study population of 100 patients. Eighty-one patients were alive a minimum of 6 months after acquisition of a negative spiral CT pulmonary arteriogram (mean, 9 months; range, 6-24 months) and were without interim diagnosis of PE, Nineteen patients died within the follow-up period after a negative spiral CT pulmonary arteriogram (mean, 3 months; range, 0-8 months); however, in none of these cases was acute pulmonary embolus reported as the cause of death. No documented PE was identified by subsequent imaging studies or autopsy within the study population. CONCLUSION: A series of 100 patients with a negative spiral CT pulmonary arteriogram did not experience significant morbidity and mortality as a result of pulmonary embolic disease within a 6-month follow-up period.