【摘要】 目的 探讨不同层厚及卷积函数重建下慢性阻塞性肺疾病肺气肿改变的CT评估1与肺功能相关性。方法 入选慢性阻塞性肺疾病（COPD）稳定期患者36例,完成肺功能,胸部深吸气相CT扫描。CT扫描在64排CT上进行,以层厚0.625 mm,1.25 mm,5 mm,7.5 mm,10 mm进行标准重建,以层厚0.625 mm,1.25 mm进行高频重建。用影思软件对全肺CT进行三维重建,在-1 020～-830 HU,每间隔10 HU设一阈值,共20个,分别计算CT值低于该阈值的低密度区比例（LAA%）,并进行视觉评分。观察这些指标与肺功能的相关性。结果 LAA%随CT层厚变薄及重建锐度升高而增加。LAA%与第1 s用力呼气容积（FEV₁）,FEV1占预计的百分比（FEV1%pred）,FEV1占用力肺活量的比例（FEV₁/FVC）,最大中段呼气流量占预计值的百分比（MMEF%pred）,总弥散量占预计值的百分比（DLCO%pred）,单位弥散量占预计值的百分比（DLCO/VA%pred）等肺功能指标相关性较好,P<0.05。本研究给出各层厚及重建方式下与各指标相关性最好的LAA%判定阈值及相关性。其中FEV₁%pred与层厚1.25 mm高频重建,以-930 HU为阈值所得LAA%相关性最好,相关系数-0.588,P=0.001。软件自动计算的LAA%与肺功能的相关性优于视觉肺气肿评分。结论 COPD低密度区比例LAA%与患者的肺功能相关,其最佳阈值及相关性受层厚及重建卷积函数的影响。更多还原

【Abstract】 Objective To study the applicability of computed tomography(CT) for emphysema evaluation in chronic obstructive pulmonary disease(COPD) patients and the effect of section thickness and reconstruction kernel.Methods Thirty-six COPD patients underwent chest CT(deep inspiratory phase) and lung function test.CT images were reconstructed using 7 different combinations of section thickness and reconstruction kernel(section thickness:0.625 mm,1.25 mm,5 mm,7.5 mm,and 10 mm;reconstruction algorithms:standard and bone).Three-dimensional reconstruction and quantitative analysis was performed using the Myrian software.Low attenuation area percent(LA A %) was determined as the percentage of lung pixels showing attenuation lower than20 thresholds ranging from-1020 HU to-830 HU.Visual scoring was done by a radiologist and a pulmonologist independently.The correlation between these indexes was analyzed.Results LAA% increased when section thickness became smaller or when the bone algorithm was used instead of the standard algorithm.LAA%was related to lung function(FEV1,FEV1 % predicted,FEV1/FVC,MMEF%red,DLCO%pred,and DLCO/VA% pred).This study rendered the best threshold of LAA% to correlate with the index of lung function test in every common combination of section thickness and reconst ruction kernel,and the corresponding correlation.The LAA% that best correlated with FEV1%pred was observed at the section thickness of 1.25 mm while using the bone algorithm with the threshold of-930 HU(r=-0.588,P=0.001).Compared to the visual scoring,that LAA% calculated using a software correlated better with lung function.Conclusion LAA% correlated with the lung function of COPD patients.The section thickness and reconstruction kernel had an effect on best threshold and correlation.更多还原