Application Of Spectral CT And Material Decomposition Analysis For Neoplastic PGGO Lesions In Lung

Objective: To investigate the clinical value of spectral CT and material decomposition analysis in diagnosis of neoplastic p GGO(pure Ground Glass Opacity)lesions in the lung and the comparison with pathologic types.Materials and Methods: From November 2011 to April 2015,34 patients with p GGO lesions underwent contrast-enhanced spectral CT scan were enrolled in this study in first affiliated of Dalian Medical University.All cases were confirmed by operation and pathology.12 Males,22 females,average age 59.85 years.According to the WHO pathology classification of lung cancer,it was divided into three groups: first group,invasive adenocarcinoma(IA),11 lesions;second group,minimally invasive adenocarcinoma(MIA),14 lesions;third group,precancerous lesions,including adenocarcinoma in situ(AIS)9 lesions and atypical adenomatous hyperplasia(AAH)2 lesions.The arterial phase Iodine concentration(IC)and water content(WC)of p GGO were measured in spectral workstation(GSI viewer)on the images of slice thickness 1.25 mm,and stored as the original datum for each region of interest.The IC,WC values of the 50 th percentile,75 th percentile,97.5th percentile and skewness values,kurtosis values were measured.Lesion volume was measured by GE ADW4.5 workstation.In the REFORMAT page,drawing region of interest(ROI)of lesionsfrom top to bottom in chest images in 1.25 mm slice thickness.The volume values(VR)of the lesions were reconstructed and obtained by the spectral workstation.Using SPSS 17.0 statistic software for analysis,the difference of IC,WC,its values in the 50 th percentile,75 th percentile and 97.5th percentile,skewness values,kurtosis values among the three groups was evaluated by Wilcoxon Rank Sum Test.The difference of lesion volume among three groups was evaluated by Wilcoxon Rank Sum Test.The difference of WC,IC,its values in the 50 th percentile,75 th percentile and 97.5th percentile,volume in any two groups of three different pathological types p GGO was evaluated by Wilcoxon Rank Sum Test.The difference of IC,WC,its values in the 50 th percentile,75 th percentile and 97.5th percentile between IA groups and non-IA(MIA?AIS?AAH)groups was evaluated by Wilcoxon Rank Sum Test.The ROC curve was used to analyze the cut-off value,sensitivity and specificity for different pathological types of p GGO.Spearman rank correlation was used to compare the correlation between the IC,WC,its values in the 50 th percentile,75 th percentile and 97.5th percentile,volume and the pathologic types.Spearman rank correlation was used to compare the correlation between the IC,WC,its values in the 50 th percentile,75 th percentile and 97.5th percentile and the lesion volumes.All measured datum were shown as the median.Statistical significance was P <0.05.Among the three groups,Statistical significance of the comparison in each of the two groups was p<0.167.Results: 1.Comparison of p GGO among different subtypes of adenocarcinoma 1.1 In IC,IC in the 50 th percentile,75 th percentile,97.5th percentile,skewness values,kurtosis values,there were not significant differences among different subtypes of adenocarcinoma for p GGO lesions(P > 0.05);there were not also significant differences between IA groups and non-IA(MIA?AIS?AAH)groups(P>0.05).1.2 In WC,WC in the 50 th percentile,75 th percentile,97.5th percentile,there were significant differences among different subtypes of adenocarcinoma for p GGO lesions(P=0.000,P=0.001,P=0.001,P=0.001).There were significant differences between IA groups and MIA groups(p=0.006,P=0.013,P=0.013,P=0.013).There were significant differences between IA groups and precancerous lesions groups(p=0.000,P=0.000,P=0.000,P=0.001).There were not significant differences between MIA groups and precancerous lesions groups(p>a'=0.0167).There were significant differences between IA groups and non-IA(MIA?AIS?AAH)groups(p=0.000,P=0.000,P=0.001,P=0.001).1.3 For p GGO lesions among different subtypes of adenocarcinoma,there was significant difference in volumes(P=0.006).For p GGO lesions between IA groups and precancerous lesions groups,there was significant difference in volumes(P=0.002).For p GGO lesions between IA groups and MIA groups,there wasn't significant difference in volumes(p=0.085).For p GGO lesions between MIA groups and precancerous lesions groups,there wasn't significant difference in volumes(P=0.051).1.4 For differential diagnosis of IA and non-IA(MIA?AIS?AAH)groups,area under curve(AUC)of WC ROC was the biggest(0.873).When the cut-off value of WC was 343.86,diagnosis sensitivity and specificity were 100% and 76% respectively.2.Correlation analysis 2.1 There were no correlation between IC,IC in the 50 th percentile,75 th percentile,97.5th percentile in the arterial phase and different subtypes of adenocarcinoma(invasive degree of tumor cells)for p GGO lesions(p=0.116,p=0.086,p=0.209,p=0.976).2.2 There were positive correlation between WC,WC in the 50 th percentile,75 th percentile,97.5th percentile in the arterial phase and different subtypes of adenocarcinoma for p GGO lesions(p=0.000,r=0.664;p=0.000,r=0.653;p=0.000,r=0.628;p=0.000,r=0.609).2.3 There was positive correlation between lesions volumes and different subtypes of adenocarcinoma for p GGO lesions(p=0.001,r=0.541).2.4 There were no correlation between IC,IC in the 50 th percentile,75 th percentile,97.5th percentile in the arterial phase and the volumes for p GGO lesions(p=0.078,p=0.051,p=0.304,p=0.231).2.5 There were positive correlation between WC,WC in the 50 th percentile,75 th percentile,97.5th percentile in the arterial phase and the volumes for p GGO lesions(p=0.011,r=0.419;p=0.015,r=0.401;p=0.016,r=0.398;p=0.002,r=0.499).Conclusion: Material decomposition analysis could quantitatively analyze neoplastic p GGO lesions.WC,WC in the 50 th percentile,75 th percentile and 97.5th percentile are helpful to distinguish the pathological subtypes for p GGO lesions.As invasive degree is the heavier in the leision,WC and percentile WC is the greater.In the next place,IC and pathological subtypes for p GGO lesions lacks of correlation.IC and volumes also lacks of correlation.This methods could provide a new way and idea for future research of p GGO cases.