Quantitative Study Of Chronic Obstructive Pulmonary Disease Using Multidetector-row Spiral CT

[Background] COPD is a disease state characterized by airflow limitation that is notfully reversible. The airflow limitation is usually both progressive and associated withan abnormal inflammatory response of the lungs to noxious particles or gases. COPDis a complex genetic disorder in which environmental factors interact with geneticsusceptibility to cause disease. Tobacco smoke is the most important environmentalrisk factor. COPD is a disease characterized by airflow limitation that is not fullyreversible and consists of small airway disease (obstructive bronchiolitis) andparenchymal destruction (emphysema), the relative contribution of which vary amongpatient. In any future clinical trials, it will be important to stratify by predominantpathophysiologic process because therapy aimed at forming new alveolar walls orpreventing their destruction will have little effect in patients for whom thepredominant disease is in small airways. Similarly, therapy aimed at inhibiting matrixremodeling in patients with predominant airway disease could be ineffective or evencontraindicated in those who have predominant parenchymal destruction.Partâ… Quantitative Study of Lung Attenuation in Patients with COPD Using MSCT[Purpose] To investigate the relationship between lung attenuation and pulmonaryfunction test (PFT) results in patients with COPD using multi-slice spiral CT.[Materials and Methods] We examined 50 patients who had received a diagnosis ofCOPD by periodic clinical and functional evalutions(stage 0,14; stage 1,8; stage 2,11;stage 3,9; stage4,8).The patients underwent 16-SCT (16-slice spiral CT) and PFTexamines, by analysis of histograms,the mean lung attenuation(MLA),the pixel index(PI) which the proportions of lung volumes with attention values below -910HU and-950HU were measured.Simple correlation analysis were used to access theconelation between MSCT measurements and PFT results. Differences of MLA,PI_-910 and PI_-950 among the patients with COPD from stage 0-4 were evaluated by Mann-Whitney U testing.[Results] Simple correlation analysis of MSCT measurements and PFT results forthe 50 patients revealed MLA, PI_-910 and PI_-950 were significantly correlated with PFTresults. MSCT measurements correlated the most closely with FEV1/FVC whichreflected airflow limitation and obstruction (r_MLA=0.498, P＜0.001; r_PI-910=-0.573, P＜0.001; r_PI-950=-0.634, P＜0.001), and then with MEF75%FVC(%P) whichreflected the function of big airway (r_MLA=0.444, P=0.001; r_PI-910=-0.492, P＜0.001;r_PI-950=-0.527, P＜0.001) and with MEF50%FVC(%P)(r_MLA=0.453, P=0.001;r_PI-910=-0.493, P＜0.001; r_PI-950=-0.515, P＜0.001) andMEF25%FVC(%P)(r_MLA=0.456, P=0.001; r_PI-910=-0.494, P＜0.001; r_PI-950=-0.489,P＜0.001) which reflected the function of small airway, the end with FEV1(%P)which reflected the degree of severity in patients with COPD and PEF(%p)which reflected the funfction of big airway. Among all of MSCT measurements, PI_-950correlated more closely with PFT results (r_FEV1=-0.551, P＜0.001; r_FEV1/FVC=-0.634,P＜0.001; r_PEF=-0.494, P＜0.001; r_MEF75%FVC=-0.527, P＜0.001; r_MEF50%EVC=-0.515,P＜0.001; r_MEF25%FVC=-0.489, P＜0.001). Among the groups from stage 0-4, therewere significant differences between the group of stage 0 and stage 4(Z_MLA=-3.485,P_MLA＜0.001; Z_PI-910=-3.413, P_PI-910=0.001; Z_PI-950=-3.345, P_PI-950=0.001), and stage2 and stage 4(Z_MLA=-3.304, P_MLA=0.001; Z_PI-910=-3.138, P_PI-910=0.002; Z_PI-950=-3.635,P_PI-950＜0.001)(P＜0.005)about MLA, PI_-910 and PI_-950, in addition between the groupof stage 1 and stage 4 about PI₉₅₀(Z_PI-950=-3.256, P_PI-950=0.001)(P＜0.005)[Conclusion] 16-SCT and its software can access the lung attenuation and degree ofemphysema by three-dimensional analysis. PI_-950 is the more sensitive index inquantitative study of lung changes in patients with COPD using QCT.Partâ…¡Quantitative Study of Airway Changes in Patients with COPD Using Multi-sliceSpiral CT[Purpose] To investigate the relationship between airway changes and PFT resultsin patients with COPD using MSCT.[Materials and Methods] We examined 50 patients who had received a diagnosis ofCOPD by periodic clinical and functional evalutions(stage 0,14; stage 1,8; stage 2,11;stage 3,9; stage4,8).The patients underwent 16-SCT and PFT examines. In our study, we used 16-SCT and its software for measuring airway dimension from the third tothe fifth generation of apical bronchus (B1) of the right upper lobe and the posteriorbasal bronchus (B10) of the right lower lobe by curved multiplaner reconstruction(CMPR), we could obtain longitudinal imanges and accurately ananlyze short axisimanges which were exactly perpendicular to the long axis at any site of airway withinner diameter as small as 2mm located anywhere in the lung. We measured bronchialinner diameter(DI), wall thickness (T)of these bronchus and bronchial externaldiameter(DE), and calculated bronchial inner area(AI), bronchial total area(AT),bronchial wall area(WA), the percentage wall area for bronchial externaldiameter(WA%), and the thickness-to- diameter ratio(TDR). Simple correlationanalysis were used to access the correlation between airway dimension and PFTresults. Differences of airway dimension among the patients with COPD from stage0-4 were evaluated by Mann-Whitney U testing.[Results] Simple correlation analysis of airway dimension and PFT results for the 50patients revealed WA% and TDR were significantly negatively correlated with PFTresults, the values of the fourth generation of bronchus correlated the most closelywith PFT results [WA% of 4th: r_FEV1=-0.535, P＜0.001; r_FEV1/FVC=-0.434, P=0.002;r_PEF=-0.556, P＜0.001; r_MEF75%FVC=-0.557, P＜0.001; r_MEF50%FVC=-0.551, P＜0.001;r_MEF25%FVC=-0.562, P＜0.001. TDR of 4th: r_FEV1=-0.527, P＜0.001;r_FEV1/FVC=-0.431, P=0.002; r_PEF=-0.557, P＜0.001; r_MEF75%FVC=-0.555, P＜0.001;r_MEF50%FVC=-0.547, P＜0.001; r_MEF25%FVC=-0.548, P＜0.001], and the values of thefifth generation of bronchus less closely with PFT results [WA% of 5th:r_FEV1=-0.386, P=0.010; r_FEV1/FVC=-0.281, P=0.064; r_PEF=-0.404, P=0.007;r_MEF75%FVC=-0.399, P=0.007; r_MEF50%FVC=-0.425, P＜0.004; r_NEF25%FVC=-0.404,P=0.007. TDR of 5th: r_FEV1=-0.375, P=0.012; r_FEV1/FVC=-0.276, P=0.070; r_PEF=-0.394,P=0.008; r_MEF75%FVC=-0.389, P=0.009; r_MEF50%FVC=-0.419, P＜0.005;r_MEF25%FVC=-0.400, P=0.007], and the correlation between the values of the thirdgeneration of bronchus and PFT results were in between [WA% of 3rd: r_FEV1=-0.472,P=0.001; r_FEV1/FVC=-0.357, P=0.011, r_PEF=-0.531, P＜0.001; r_MEF75%FVC=-0.518,P＜0.001; r_MEF50%FVC=-0.476, P＜0.001; r_MEF25%FVC=-0.436, P=0.002. TDR of 3rd:r_FEV1=-0.469, P=0.001; r_FEV1/FVC=-0.352, P=0.012; r_PEF=-0.530, P＜0.001;r_MEF75%FVC=-0.512, P＜0.001; r_MEF50%FVC=-0.471, P=0.001; r_MEF25%FVC=-0.427,P=0.002]. Although T, DE and AT con-elated with PFT results, their correlation is less closely than WA% and TDR.The T of the fifth generation of bronchus correlatedmore closely with MEF50%FVC and MEF25%FVC than the third and fourthgeneration of bronchus (5th, r_MEF50%FVC=-0.343, P_MEF50&FV=0.023,r_MEF25%FVC=-0.302,P_MEF25%FVC=0.046; 4th, r_MEF50%FVC=-0.263, P_MEF50%FV=0.068, r_MEF25%FVC=-0.236,P_MEF25%FVC=0.102; 3rd, r_MEF50%FVC=-0.231, P_MEF50%FV=0.106,r_MEF25%FVC=-0.151,P_MEF25%FVC=0.296). About WA% and TDR among the groups from stage 0-4, therewere significant differences between the group of stage 0 and stage 2(Z_WA%=-3.339,P_WA%=0.001; Z_TDR=-3.339, P_TDR=0.001), stage 0 and stage 3(Z_WA%=-2.961,P_WA%=0.003; Z_TDR=-2.961, P_TDR=0.003), and stage 1 and stage 2(Z_WA%=-3.138,P_WA%=0.002; Z_TDR=-3.138, P_TDR=0.002)(P＜0.005) in the third generation of bronchus;about WA% and TDR in the fourth generation of bronchus, there were significantdifferences between the group of stage 0 and stage 2(Z_WA%=-3.449, P_WA%=0.001;Z_TDR=-3.449, P_TDR=0.001), stage 0 and stage 3(Z_WA%=-3.140, P_WA%=0.002;Z_TDR=-3.140, P_TDR=0.002), stage 1 and stage 2(Z_WA%=-3.303, P_WA%=0.001;Z_TDR=-3.303, P_TDR=0.001), and stage 1 and stage 3 (Z_WA%=-3.046, P_WA%=0.002;Z_TDR=-3.046, P_TDR=0.002)(P＜0.005); about WA% and TDR in the fifth generation ofbronchus, there was significant differences only between the group of stage 0 andstage 2 about WA%(Z_WA%=-3.150, P_WA%=0.002)(P＜0.005).[Conclusion] 16-SCT and its software can more accurately ananlyze bronchial shortaxis imanges which were exactly perpendicular to the long axis at any site of airwaywith inner diameter as small as 2mm located anywhere in the lung by CMPR. WA%and TDR were significantly correlated with PFT results and the more sensitiveindexes in quantitative study of airway changes from the third to the fifth generationof bronchus in patients with COPD using MSCT. WA% and TDR correlated moreclosely with PEF (%p) and MEF75%FVC (%p) which reflected the function of bigairway and MEF50%FVC (%p) and MEF25%FVC (%p) which reflected the functionof small airway compared with other parameters of airway. The correlation between Tand MEF50%FVC (%p) and MEF25%FVC (%p) became more closely followingthe grading of bronchial tree, thus T is a more sensitive index as well as WA% andTDR in quantitative assessment of small airway disease in patients with COPD usingMSCT. There was bronchiectasis in the patients with COPD, which could affect theassessment of the conelation between airway dimensions and indexs of PFT resultsabout the degree of severity in patients with COPD.