基于双气相CT定量分析保存率肺功能受损患者的肺气肿及小气道病变

Quantitative analysis of emphysema and small airway disease in patients with preserved ratio impaired spirometry using dual-phase CT

目的:基于双气相CT探讨保存率肺功能受损(PRISm)患者的肺部定量影像特征,包括小气道病变及肺气肿。方法:纳入延安大学附属医院2018年12月-2020年12月的患或未患慢性阻塞性肺病(COPD)的吸烟者,根据肺功能检查结果分为6组。PRISm组定义为第1秒用力呼气容积与用力肺活量比值(FEV1/FVC)≥70%,第1秒用力呼气容积实测值占预测值百分比(FEV1%pred)<80%;正常对照组定义为FEV1/FVC≥70%,FEV1%pred≥80%;COPD GOLD 1~4级定义为FEV1/FVC<70%。将所得胸部双气相CT图像导入“数字肺”自动检测平台进行分析,CT定量参数包括全肺及各肺叶肺气肿区域百分比(Emph%)和小气道病变区域百分比(fSAD%)。6组间的临床基线资料和CT定量参数比较采用单因素方差分析或Kruskal-Wallis H检验。结果:共有159例受试者(PRISm组31例;正常对照组32例;GOLD 1~4级分别为14例、27例、33例、22例)。GOLD 2~4级全肺及各肺叶的Emph%和fSAD%均较PRISm组显著增加(P均<0.05),PRISm组与GOLD 1组左肺及双肺上叶的Emph%差异有统计学意义(P<0.05)。PRISm组与对照组间全肺及各肺叶的Emph%和fSAD%差异无统计学意义(P均>0.05)。PRISm组右肺上叶、右肺中叶及左肺上叶的Emph%和fSAD%均较右肺下叶和左肺下叶显著增加(P均<0.05)。结论:双气相CT能够定量评估PRISm患者的肺部影像特征,PRISm的全肺及各肺叶肺气肿和小气道病变分布及严重程度更接近GOLD 1~2级,尚不明确PRISm是否构成了肺功能正常人群发展到COPD的中间阶段。

Objective:To explore the quantitative chest tomographic features of preserved ratio impaired spirometry(PRISm)based on dual-phase CT,including small airway disease and emphysema.Methods:Smokers with or without chronic obstructive pulmonary disease(COPD)from Yan'an University Affiliated Hospital between December 2018 and December 2020 were included and divided into six groups based on pulmonary function test.PRISm was defined as a forced expiratory volume in the 1 second/forced vital capacity(FEV1/FVC)≥70%and forced expiratory volume in 1 second as a percentage of predicted value(FEV1%pred)<80%.Healthy control was defined as FEV1/FVC≥70%,FEV1%pred≥80%.COPD GOLD 1~4 grades were defined as FEV1/FVC<70%.The obtained chest dual-phase CT images were imported into the"Digital Lung"automatic detection platform for analysis.CT quantitative parameters included the percentage of emphysematous regions(Emph%)and small airway disease regions(fSAD%)in the whole lung and each lung lobe.Clinical baseline data and CT quantitative parameters were compared among the six groups using one-way analysis of variance(ANOVA)or the Kruskal-Wallis test.Results:A total of 159 subjects(31 PRISm,32 healthy con-trols,14 GOLD stage 1,27 GOLD stage 2,33 GOLD stage 3,22 GOLD stage 4)were included in the final analysis.Emph%and fSAD%were significantly greater in the GOLD 2~4 groups than those in the PRISm group for each of the five lobes and the whole lung(all P<0.05).The difference in Emph%between the PRISm group and the GOLD grade 1 group in the left lung and both upper lobes was statistically significant(P<0.05).There was no significant difference in Emph%and fSAD%in the whole lung and different lobes between the PRISm group and the control group(all P>0.05).The Emph%and fSAD%in the right upper lobe,right middle lobe,and left upper lobe of the PRISm group were significantly higher than those in the right lower lobe and left lower lobe(all P<0.05).Conclusion:Dual-phase CT can quantitatively evaluate the imaging characteristics of lungs in patients with PRISm.The distribution and severity of emphysema and small airway disease in the whole lung and lobes of PRISm were closer to those of GOLD stage 1~2.However,it is still unclear whether PRISm represents an intermediate stage in the development of COPD from a population with normal lung function.