Pulmonary fat embolism induced intravenous injection of autologous bone marrow in rabbit: CT and pathologic correlation

To evaluate the correlation between CT and pathologic findings of pulmonary fat embolism in rabbits. In 16 rabbits, pulmonary fat embolism was induced by intravenous injection of autologous 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 immediately 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 specimens were obtained immediately after the last CT scan. The earliest CT findings of pulmonary fat embolism in rabbits were peripheral lung lucency(16/16, 100%), perivascular ground-glass(12/16, 75.0%) and enlargement of the central pulmonary artery(11/16, 68.8%). Pathologically, perivascular ground-glass opacity correlated with extensive perivascular alveolar congestion 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 occlusion of the pulmonary artery and decreased perfusion and air trapping induced by arterial and bronchial spasm 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, pulmonary nodules correlated with focal inflammation surrounding an artery and parenchymal opacity correlated with parenchymal consolidation and hemorrhagic edema. CT scans and pathologic specimens obtained 7 days after embolization showed improvement of parenchymal lung abnormalities. 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