CT Quantitative Study Of Lung Volume And Small Airway In Type 2 Diabetes Mellitus

Objective:Early detection of diabetic lung damage is a difficult point in clinical work.Through chest CT scanning and quantitative measurement in patients with type 2diabetes mellitus,the changes of lung volume,vascular volume and small airway of lung damage in type 2 diabetes mellitus were discussed in order to provide objective basis for early detection of diabetic lung damage.This study is divided into three parts:Part one:Through quantitative analysis of the lungs of patients with T2DM lung damage,to explore the changes of whole lung volume and lung density and their correlation with lung function in patients with T2DM lung damage,and to evaluate the diagnostic value of CT quantitative parameters in type 2 diabetic lung damage,so as to screen the imaging biomarkers for early evaluation of diabetic lung damage.Part two:Quantitative analysis of small airway lesions in patients with type 2diabetes based on CT parameter effect map PRMf SAD%and PRMempha%,and to investigate the relationship between pulmonary vascular volume and renal microangiopathy in patients with T2DM nephropathy。Part three:Through quantitative analysis of the lungs of patients with T2DM nephropathy,and comparing the changes of whole lung volume,average density and vascular volume among normal subjects,non-diabetic nephropathy group,early diabetic nephropathy group and clinical diabetic nephropathy group,to explore the relationship between T2DM pulmonary vascular volume and renal microangiopathy.Part one1.Materials and methodsA retrospective study was conducted on 150 patients with T2DM pulmonary function damage diagnosed in the affiliated Hospital of Yan’an University from January2021 to March 2022.30 patients with other pulmonary diseases and image quality reasons were excluded.Finally,120 patients with T2DM lung damage and 60 normal volunteers were included.According to the grading of pulmonary function,T2DM patients with restrictive pulmonary ventilation dysfunction（forced vital capacity<80%）were classified as patients with T2DM pulmonary function impairment,and were divided into mild T2DM pulmonary function impairment group（FEV1%predicted value≥70%）and moderate and severe T2DM pulmonary function impairment group（FEV1%expected value<70%）.Normal physical examination subjects were included in the normal control group.The original data obtained by inspiratory CT scan are imported into the lung density measurement module of the"digital lung"medical imaging quantitative diagnosis system.The quantitative indexes of CT were extracted automatically by lung fissure segmentation:the whole lung volume and the CT quantitative parameters reflecting the lung density[the percentage of the density attenuation area of 910HU in the whole lung（LAA910%）,the volume of the density attenuation area of both lungs lower than-950HU in the whole lung（LAA950%）,the average density].Pulmonary function indexes such as FVC,FVC%,FEV1,FEV1%and FEV1/FVC%were selected.The differences of CT quantitative index and pulmonary function among the three groups were compared by single factor analysis of variance or nonparametric test.Pairwise comparison was made by LSD-t method or Kruskal-Wallis H method.Pearson or Spearman was used to analyze the correlation between CT quantitative index and pulmonary function.FEVC%was used as state variable,bilateral lung volume,LAA910,LAA950,LAA910%,LAA950%and average density were used as test variables to draw the subject working characteristic（receiver operating characteristic curve,ROC）curve and calculate the area under the curve.The best accuracy,cutoff value,sensitivity and specificity of whole lung volume,LAA910,LAA950,LAA910%,LAA950%and average density prediction FVC%<80%（for all subjects to distinguish patients with diabetic lung damage）were obtained.2.ResultsHbA_1cin mild,moderate and severe T2DM pulmonary function damage group was significantly higher than that in normal control group,and there were significant differences among FVC,FVC%,FEV1 and FEV1%groups,but there was no significant difference in age,sex,BMI and FEV1/FVC%among the three groups.There were significant differences in whole lung volume,LAA910,LAA950,LAA910%,LAA950%and average density between the two groups.The whole lung volume,LAA910,LAA950,LAA910%and LAA950%were the lowest and the average density was the highest in the moderate and severe T2DM pulmonary function damage group.The results of Spearman correlation analysis showed that each pulmonary function index（FVC,FVC%,FEV1,FEV1%）was positively correlated with CT quantitative index（whole lung volume,LAA910,LAA950,LAA910%,LAA950%）（rs=0.146～0.719,P<0.001）,and negatively correlated with CT quantitative index（average density）（rs=0.197～0.678,P<0.001）.Compared with other CT quantitative indexes（LAA910,LAA950,LAA910%,LAA950%）.Among the quantitative indexes of CT,the correlation between whole lung volume and pulmonary function indexes（FVC,FVC%,FEV1,FEV1%）was the highest（rs=0.225～0.819,P<0.001）.ROC curve analysis showed that whole lung volume,LAA910,LAA950,LAA910%,LAA950%and average density could be used to distinguish the damage of lung function in patients with diabetes mellitus（P<0.01）.The area under the curve from high to low is 0.890,0.876,0.842,0.839,0.822,0.751,among which the diagnostic efficiency of whole lung volume is the best,AUC is 0.890（95%CI:0.883～0.890,P<0.000）,critical value is 4559,sensitivity 88.3%,specificity 80.0%.the diagnostic efficacy of LAA950%was the lowest,with an AUC of 0.751（95%CI:0.760～0.884,P<0.000）,a critical value of 18.27,a sensitivity of 76.7%,and a specificity of 63.3%.3.Brief summaryQuantitative CT can objectively and quantitatively evaluate the lung injury in patients with T2DM,and has a good correlation with lung function.T2DM lung damage leads to the decrease of whole lung volume and the increase of average density,in which the whole lung volume has a better diagnostic efficacy in distinguishing T2DM lung function damage.Part two1.Materials and methodsA total of 72 patients with T2DM who underwent biphasic chest CT examination in our hospital from June 2022 to December 2022 were included.Except for patients with other pulmonary diseases and image quality reasons that could not be processed,58patients with T2DM were included in the T2DM group,and 36 normal volunteers were included in the control group.The original DICOM data of biphasic scan were imported into the"digital lung"biphasic test tool,and the image registration was carried out.According to the CT threshold,the PRM parameters PRMfsad%,PRMempha%,PRMnormal%and other air retention parameters including EXI-856%and MLDex/in were obtained.Pulmonary function index:FEV1%,FVC%,FEV1/FVC%,PEF%and laboratory index glycosylated hemoglobin.Independent sample T test,Mann-Whitney U test or c2 test were used to compare the two groups.Pearson or Spearman was used to analyze the correlation between CT quantitative index and pulmonary function and glycosylated hemoglobin.2.ResultsThe HbA_1cand course of disease in the T2DM group were significantly higher than those in the normal control group,and the pulmonary function（FVC%,FEV1%,PEF%）in the T2DM group was significantly lower than that in the normal control group.There was no significant difference in age,sex,height,weight,BMI and FEV1/FVC%between the two groups.The CT quantitative indexes EXI-856%,MLDex/in,PRMfsad%and PRMempha%in the T2DM group were significantly higher than those in the normal control group,except that PRMnormal%was significantly lower than that in the normal control group.The results of Pearson or Spearman correlation analysis showed that pulmonary function indexes（FVC%,FEV1%,PEF%）were correlated with CT quantitative parameters（P<0.001）.The air retention parameters EXI-856%and MLDex/in were negatively correlated with pulmonary function FEV1%,FVC%and PEF%（rs=-0.241～-0.343,P<0.05）.The PRM parameters such as PRMfsad%and PRMempha%were negatively correlated with pulmonary function FEV1%,FVC%and PEF%（rs=-0.290～-0.440,P<0.001）,and positively correlated with PRMnormal%（rs=0.276～0.341,P<0.001）.Compared with other CT quantitative indexes（EXI-856%,MLDex/in,PRMempha%,PRMnormal%）,the correlation between PRMfsad%and pulmonary function indexes（FVC%,FEV1%,PEF%）was the highest（rs=0.369～0.440,P<0.001）.The correlation between HbA_1cand EXI-856%,MLDex/in,PRMfsad%,PRMempha%,PRMnormal%was 0.327,0.510,0.603,0.414,-0.295 respectively,the difference was statistically significant（P<0.01）.3.Brief summaryThere is small airway damage in patients with T2DM.The PRMfsad%parameters based on dual gas registration CT quantitative technique can effectively evaluate the early small airway disease in patients with diabetes,and can be used as an effective tool to evaluate the severity of the disease and long-term follow-up to quantitatively monitor the occurrence and development of small airway in patients with diabetes.Part three1.Materials and methodsFrom January 2022 to December 2022,97 patients with T2DM were diagnosed in Cardiovascular and Cerebrovascular Disease Hospital of affiliated Hospital of Yan’an University and 23 healthy controls were collected.In this study,urinary microalbuminuria/creatinine（ACR）was included to evaluate the severity of diabetic nephropathy.Normal healthy people were included in the control group（n=23）.T2DM patients with ACR<30mg/g were included in the non-diabetic nephropathy group（group A1,n=45）,ACR30～300mg/g was included in the early diabetic nephropathy group,microalbuminuria group（group A2,n=46）and T2DM patients with ACR>300mg/g were included in the clinical diabetic nephropathy group.Massive albuminuria group（23 cases）.The quantitative index of CT is the same as the first part,and the quantitative index of blood vessel volume is introduced.The statistical method refers to the first part.2.ResultsCompared with the control group,there were significant differences in disease course,ACR,glycosylated hemoglobin,FVC,FVC%,FEV1 and FEV1%among A1,A2and A3 groups.There was no significant difference in age,sex,height,weight,BMI,apolipoproteinα,homocysteine and FEV1/FVC%among the three groups.The average density of A2 and A3 groups was higher than that of control group and A1 group,while the whole lung volume,LAA910,LAA950,LAA910%,LAA950%and vascular volume of A2 and A3 groups were lower than those of control group and A1group.The results of Pearson or Spearman correlation analysis showed that the whole lung volume,LAA910,LAA950,LAA910%,LAA950%were negatively correlated with ACR（rs=-0.413～-0.453,P<0.05）,and The average density is positively correlated with ACR（rs=0.410,P<0.05）.HbA_1cwas negatively correlated with whole pulmonary vascular volume（rs=-0.172,P<0.05）,but there was no significant difference between glycosylated hemoglobin and other quantitative indexes.3.Brief summaryQuantitative CT can be used to detect the structural changes in patients with T2DM nephropathy,mainly the decrease of whole lung volume and vascular volume and the increase of average density,and the change of T2DM pulmonary vascular volume is related to renal microvascular damage.Conclusions1)The main results are as follows:1quantitative CT has a good correlation between whole lung volume,lung density and lung function,which can be used to detect the changes of lung function in patients with type 2 diabetes mellitus.2)There is small airway damage in patients with T2DM.The PRMfsad%parameters based on dual gas registration CT quantitative technique can effectively evaluate the early small airway disease in patients with diabetes,and can be used as an effective tool to evaluate the severity of the disease and long-term follow-up to quantitatively monitor the occurrence and development of small airway in patients with diabetes.3)Quantitative CT can be used to detect the structural changes in patients with T2DM nephropathy,mainly the decrease of whole lung volume and vascular volume and the increase of average density,and the change of T2DM pulmonary vascular volume is related to renal microvascular damage.