实验性呼吸窘迫综合征

CT Study of Experimental RDS

目的：探讨实验性呼吸窘迫综合征（ＲＤＳ）的ＣＴ表现、病理基础及与ＰａＯ２的关系。材料和方法：制作不同程度肺损伤的“油酸型家兔ＲＤＳ模型”２５只，并于注射油酸前、及后３０分、６０分、１２０分钟共四次取股动脉血测定ＰａＯ２及作ＣＴ扫描分析并测定肺平均密度值，同时作病理对照检查。结果：ＲＤＳ模型的ＣＴ影像特点主要有：１均匀与不均匀密度的实变阴影，均匀实变以肺不张和肺泡水肿为主，有一定的重力依赖性，不均匀斑片影与正常充气肺组织相间；２肺尖区一过性过度肺充气，见于３例轻型及３例重型模型的早期（３０分），表现为平均密度明显低于正常，未见于文献报道；３肺气囊，见于２例重型的１２０分钟ＣＴ像，病理上为肺结构破坏，提示不可逆的严重损伤。正常肺平均密度与ＰａＯ２分别为７５９．３±１８．９Ｈｕ、１２．３５±０．６６ＫＰａ。轻型ＲＤＳ肺平均密度与ＰａＯ２与正常相比无明显差异，但肺尖区平均密度低于正常（０．０１＜ｐ＜０．０５）。重型ＲＤＳ肺平均密度与ＰａＯ２有明显负相关（ｒ＝０．９０，ｐ＜０．０１）。结论：特征性的ＣＴ影像有助于ＲＤＳ的诊断，肺尖区一过性过度肺充气有助于ＲＤＳ的早期诊断，肺气囊有助于ＲＤＳ病情及予后判断；利用平?

Purpose:To study CT findings,pathology of experimental acute respiratory distress syndrome and relationship to PaO2.Matetials and Methods:25 rabbit models of loeic acid-induced RDS were made in different degrees of lung injuries.PaO2 measurement and CT scan were done before injection and 30min,60min,120min after injection of loeic acid respectively.The mean lung density was measured on CT images together with pathologic examination.Results:Characteristic CT findings of RDS were.1.Homogeneous and inhomogeneous opacities-Consolidated areas were related to gravity-dependent for some extents but mainly due atelectasis and edema in pathology.Patchy areas were sporadically distributed and interpolated with normal areas.2.Compensating overinflation of apex were seen in 4 mild cases and 5 severe ones and the mean density was inferior to normal.3.Pneumatoceles were seen in 2 severe cases(2hr images)and lung structures,were damaged.Normal lung mean density and PaO2 were 759.3±18.9Hu,12.35±0.66KPa,rspectively. Lung density of mild cases were lower(0.01<p<0.05).Mean density of severe cases were significantly with negtive relation to PaO2(r=0.90,p<0.01).Conclusion:Characteristic CT signs help to diagnose RDS,as overinflation for the early diagnosis and pulmonary air cysts to formation.Providing the prediction of degree and prognosis.Mean density on CT scan is also useful to evaluate RDS.