CT Pulmonary Angiography: Quantification of Pulmonary Embolus as a Predictor of Patient Outcome—Initial Experience

PURPOSE: To determine whether quantification of pulmonary embolus (PE) with computed tomographic (CT) pulmonary angiography by using a standardized index is a predictor of patient outcome. MATERIALS AND METHODS: Multi-detector row CT was performed in 59 hospitalized patients (mean age, 61 years; age range, 22-89 years). PE was identified retrospectively by two radiologists who were blinded to patient outcome. A pulmonary arterial obstruction index was derived for each set of images on the basis of embolus size and location. By using logistic regression, PE indexes were compared with patient outcome-survival or death-to determine if there was a correlation between PE volume and survival. RESULTS: The PE index is a significant predictor of patient outcome (P =.002). One of 53 patients (1.9%) with an index of less than 60% died. Cause of death was end-stage malignancy. Five of six patients (83%) with an index of 60% and higher died. All five deaths were related to the presence of PE. The one survivor with a PE index higher than 60% received thrombolytic therapy. By using a cutoff of 60%, the PE index was used to identify 52 of 53 (98%) patients who survived and five of six (83%) patients who died. CONCLUSION: Preliminary evidence suggests that quantification of clot with CT pulmonary angiography is an important predictor of patient death in the setting of PE.