肺高分辨率CT“马赛克”衰减与肺功能的相关性研究

目的:探讨小气道病变时高分辨率CT(HRCT)所示"马赛克"衰减程度与肺功能检查指标的相关性,并评价其临床意义.方法:选择HRCT上显示"马赛克"衰减病例40例,由2位放射诊断医师对"马赛克"衰减及低衰减区域的程度进行半定量分析,用秩相关检验分析半定量指标与肺功能参数的相关性.结果:"马赛克"衰减程度与FEF25%呈显著负相关(r=-0.45,P<0.05),与FEV1、FEF50%无相关性(分别为r=-0.29,P>0.05 和r=-0.16,P>0.05).而低衰减区域的程度与FEF25%、FEV1相关性均较好(分别为r=-0.58,P<0.001和r=-0.38,P<0.05),与FEF50%亦无相关性(r=-0.309,P>0.05).结论:"马赛克"衰减作为小气道病变的主要征象,其程度与FEF25%具有良好的相关性,而低衰减区域作为小气道阻塞的直接后果,其程度与FEV1、FEF25%具显著相关性,即使肺功能检查结果正常时,也可以辅助诊断临床可疑的小气道阻塞.

Correlation of Mosaic Attenuation on HRCT of lung with functional abnormalities

Objective:To investigate the correlation of the extent of mosaic attenuation on HRCT with results of pulmonary function tests (PFTs).Methods:Forty patients with mosaic attenuation on HRCT were collected in our study.The extent of mosaic attenuation and decreased attenuation of CT scans were scored semiquantitatively by two radiologists.The correlation of semiquantitative scores with pulmonary function tests was evaluated.Results:The score of mosaic attenuation had significantly negative correlation with forced expiratory flow at 25% of vital capacity (r=-0.45, P < 0.05 ),but it was not correlated significantly with forced expiratory volume in one second (FEV 1) and forced expiratory flow at 75% of vital capacity (r=-0.29, P >0.05; r=-0.16, P >0.05, respectively).Meanwhile,the score of decreased attenuation had significantly negative correlation with forced expiratory volume in one second and forced expiratory flow at 25% of vital capacity (r=-0.58, P <0.001;r= -0.38 , P <0.05 respectively),but it was not correlated with forced expiratory flow at 50% of vital capacity(r=-0.309, P >0.05).Conclusion:Mosaic attenuation as a major feature of small airway diseases on HRCT,had significantly negative correlation with forced expiratory flow at 25% of vital capacity and forced expiratory volume in one second.They may permit detection of airway obstruction and function of small airway in patients with clinically suspected chronic airway diseases even when PFTs are normal.