Pulmonary Fat Embolism Induced Intravenous Injection of Autologous Bone Marrow in Rabbit: CT and Pathologic Correlation

Purpose : To evaluate the correlation between CT and pathologic findings of pulmonary fat embolism in rabbits. Materials and Methods : In 16 rabbits, pulmonary fat embolism was induced by intravenous injection of autol-ogous bone marrow(mean 3.3 mL). Chest CT scans were obtained immediately(within 1 hour), and 1, 3, and 7 days after embolization. The rabbits were divided into four groups. Group 1 underwent CT scanning immedi-ately after embolization, group 2 immediately and 1 day after embolization, group 3 immediately, 1 day and 3 days after embolization, group 4 immediately, 1 day, 3 days and 7 days after embolization. Pathologic speci-mens were obtained immediately after the last CT scan. Results : The earliest CT findings of pulmonary fat embolism in rabbits were peripheral lung lucency(16/16, 1 00 %), perivascular ground-glass (12/16, 75.0 %) and enlargement of the central pulmonary artery(11/16, 6 8 .8 %). Pathologically, perivascular ground-glass opacity correlated with extensive perivascular alveolar con-gestion and enlargement of the central pulmonary artery correlated with perivascular connective tissue edema and reactive pulmonary arterial engorgement. Peripheral lung lucency was probably caused by embolic occlu-sion of the pulmonary artery and decreased perfusion and air trapping induced by arterial and bronchial s-pasm associated with hypoxia. CT scans obtained 1 and 3 days after embolization showed nodules and patchy ground-glass opacity and consolidation. Aggregation of nodules resulted in patch opacities. Pathologically, pul-monary nodules correlated with focal inflammation surrounding an artery and parenchymal opacity correlat-ed with parenchymal consolidation and hemorrhagic edema. CT scans and pathologic specimens obtained 7 days after embolization showed improvement of parenchymal lung abnormalities. Conclusion : Pulmonary fat embolism in rabbits show CT and pathologic findings which vary with dynamic change. Typical earliest findings of pulmonary fat embolism were peripheral lung lucency, perivascular ground-glass opacity and enlargement of the central pulmonary artery.