Abstract：Objective: To observe dynamic changes of lung parenchyma with acute pulmonary embolism(PE) in rabbit model and correlation with pathological findings. Methods: Twenty-four experimental rabbit models of acute PE were established through femoral vein using gelatin sponge as embolus materials, which were randomly divided into 4 groups. Plain and enhanced CT scans were performed before embolization and after embolization at 2h, 1d, 3d, 7d(i.e. group 1, 2, 3, and 4, n=6, respectively) to observe the dynamic changes of PE. Rabbits were killed to analyze the pathologic basis of the corresponding changes. Comparing to pathology as a standard of reference, CT numbers of the embolic areas and normal pulmonary parenchyma were measured in the standard non-enhanced and enhanced CT, respectively. Paired student t test was used to compare changes of CT values. Results: The CT findings of PE at 2h after embolization reveals areas of decreased attenuation(6/6). CT revealed pulmonary oligemia(4/6), mosaic signs associated with crescent-shaped shadow of pleura(1/6) at 1 day after embolization, and 1 rabbit showed normal. Lung consolidation was displayed in 4 rabbits after 3 days, 1 rabbit showed mosaic sign, 1 rabbit showed ground-glass change. Consolidation and infarction were displayed in 4 rabbits after 7 day, accompanied by pleural effusion, pleura thickening and lung bullae; 1 rabbit displayed pulmonary oligemia, 1 rabbit showed local pleural thickening and small amount of pleural effusion. On unenhanced CT scans, there was no significant difference between pre-embolism and post-embolism of embolic areas of the 2h and the 1 day group(P>0.05). There were significant differences of CT values and net increased CT values between preembolism and postembolism of the embolic areas(P<0.01) after 2h and 1 day. After embolism, there was no significant difference on CT values of 2h and 1 day groups between embolism areas and normal pulmonary parenchyma(P>0.05). On enhanced CT scans, there was significant difference for CT values and net increased CT values between embolic areas and normal pulmonary parenchyma(P<0.01) after 2h, 1 day; but there was no significant difference of CT values of unenhanced and enhanced of 3 day and 7 day groups respectively(P>0.05). Conclusion: The pulmonary embolism models was established by using gelatin sponge as embolus. CT, especially enhanced CT can depict the dynamic changes of the PE from pulmonary oligemia to consolidation and infarction, which were correlated well with pathologic findings.
2009, Vol. 20 
