多层螺旋CT低剂量扫描对阻塞性肺疾病分级定量测量的初步研究

目的探讨慢性阻塞性肺疾病(COPD)病人右肺上叶尖段支气管在多层螺旋 CT(MSCT)上行气道测量的可行性以及各级别 COPD 支气管和肺密度的变化.方法随机选取 COPD 病人15例,采用 MSCT 行胸部低剂量 CT 平扫,重组并评价右肺上叶尖段支气管气道壁厚度与直径的比率(TDR)和气道壁面积百分比(WA%),并与每例病人随机选择的内径<2 mm 支气管的平均 TDR 和平均 WA%进行比较.统计学分析采用 t 检验和 Pearson 检验.另外随机选择 COPD 病人55例,根据肺功能检查按慢性阻塞性肺疾病诊治指南(2007年修订版)标准分为4组,其中 COPD 1级16例,2级16例,3级14例,4级9例.同时选取非胸部病变病人15例作为对照组.5组病人均行 MSCT 低剂量吸气相全肺扫描,测量平均肺密度(MLA)、体素指数(VI)、右肺上叶尖段支气管管腔面积(Ai)、TDR 和 WA%,并进行比较.统计学分析采用 One-Way ANOVA 单因素方差分析.结果①右肺上叶尖段支气管所测得的 TDR 和 WA%与小气道测量结果的平均值存在差异,但具有良好的相关性(r 分别为0.793和0.784).②各组病例所测得的 MLA 随 COPD 分级的增高呈逐渐减低趋势,VI 则逐渐增高;但相邻两级之间差异不具有统计学意义;3、4级病例的 Ai减小;除3级与4级外,相邻两级病人所测得的 TDR 差异不具有统计学意义;各组之间 WA%差异均具有统计学意义.结论右肺上叶尖段支气管所测得的 TDR 和 WA%与小气道测量结果的平均值存在良好的相关性.WA%是反映气道重塑、管腔狭窄最敏感的指标.

Primary study of quantitative measurement in different grades of COPD using low-dose multislice CT

Objective To study the feasibility of airway measurement at the trunk of apical bronchus of right upper lobe in chronic obstructive pulmonary disease (COPD), and airway dimensions and lung density changes in different COPD stages. Methods 1) Fifteen randomly selected COPD patients underwent low-dose chest multi-slice CT scan. The wall thickness-to-diameter ratio (TDR) and percentage wall area (WA%) at apical bronchus of right upper lobe section, and mean TDR and WA% of small airway (<2 mm) were calculated. 2) Another fifty-five randomly selected COPD patients were divided into 4 groups on the basis of pulmonary function tests. There were sixteen patients with grade 1, sixteen patients with grade 2, fourteen patients with grade 3, and nine patients with grade 4. Fifteen non-COPD patients were selected as controls. The total lung was scanned with low-dose multi-slice CT during inspiration. The mean lung attenuation (MLA) and voxel index (VI) were measured. Inner area of bronchus (Ai), TDR and WA% of the apical bronchus of right upper lobe were measured. Results 1) The TDR of the apical bronchus of right were smaller than the mean TDR of the small airways; The WA% of the apical bronchus of right were larger than the mean WA% of the small airways; but there were good correlation (r=0.793 and 0.784, respectively). 2) The MLA values were decreased with increase of COPD stage. The VI values were increased with increase of COPD stage. However, the values did not differ between adjacent stages. The luminal areas of stage 3-4 patients were smaller than that of other stages. There was no statistics difference in TDR between adjacent groups, except between stages 3 and 4. For WA%, the higher stage group had higher WA%. Conclusion There were good correlations for TDR and WA% between the apical bronchus of right upper lobe and small airway. WA% is the most sensitive index for detecting thickened airway.