An Experimentally Induced Fat Embolism in the Rabbit Lung: High-resolution CT and Pathologic Findings

Abstract

Purpose: To assess the high-resolution CT and pathologic findings of fat embolism experimentally induced in rabbit lung. Materials and Methods: Twelve rabbits were divided into four groups, namely control, 2-hour, 24-hour, and 72-hour, with three rabbits in each, and closed tibiofibular fractures were induced. After the rabbits were sacrificed, high-resolution CT scanning of the artificially inflated lungs was performed, and the CT findings were analyzed by two radiologists. They determined the presence or absence of ground glass opacity or consolidation, the extent of the lesions (using a 10% grading scale), and their distribution, reaching a consensus. The pathologic findings were analyzed using the specimens prepared by H & E and Oil-red O staining. Results: Although the high-resolution CT findings of pulmonary fat embolism were nonspecific, bilateral patchy ground glass opacity (100%), and focal air-space consolidation surrounding the bronchovascular bundle (89%) were most common. In all groups, the occlusion of vessels by fat globules was confirmed by Oil-red Ostaining. The microscopic findings included focal pulmonary hemorrhage, edema, alveolar collapse, and extensive infiltration of inflammatory cells in the lung parenchyma. The 24-hour group showed more extensive change in high-resolution CT and pathologic findings than did the others. Conclusion: Fat embolism in rabbit lung may occur after closed tibio-fibular fracture. The extent of the lesion revealed by high-resolution CT correlated closely with the pathologic findings. High-resolution CT may thus be helpful for the detection of pulmonary fat embolism and evaluation of its extent.