UNSUSPECTED PULMONARY-EMBOLISM - PROSPECTIVE DETECTION ON ROUTINE HELICAL CT SCANS

PURPOSE: to determine the prevalence of unsuspected pulmonary embolism (PE) on routine thoracic helical computed tomographic (CT) scans and to quantify the improvement in PE detection by using a cine-paging mod e on a workstation instead of hard-copy review. MATERIALS AND METHODS: Seven hundred eighty-five patients referred for routine contrast medi um-enhanced thoracic CT within 9 months were prospectively recruited. Helical CT was performed. Studies were prospectively interpreted by fo ur radiologists. Two radiologists performed routine, undirected, hard- copy consensus review for official interpretation; two of three thorac ic radiologists independently performed a dedicated workstation-based search for PE. The presence of PE involving the main, lobar, or segmen tal pulmonary arteries was assigned a score of 1-5 (1 = definitely neg ative, 5 = definitely positive) by each independent reviewer. patients with a score of 4 or 5 underwent lower-extremity ultrasound, ventilat ion-perfusion scintigraphy, or both followed by pulmonary CT angiograp hy if the findings were still equivocal. RESULTS: Twelve (1.5%) of the 785 patients had unsuspected PE, with an inpatient prevalence of 5% ( eight of 160) and an outpatient prevalence of 0.6% (four of 625). Of t he 12 patients with unsuspected PE. A dedicated workstation-based sear ch resulted in detection of PE in three more patients (25%) than did h ard-copy interpretation. CONCLUSION: The prevalence of unsuspected PE was highest among impatiens with cancer. A directed, workstation-based search can improve the PE detection rate over that with hard-copy rev iew.