The Application Of Quantitative Analysis Of Pulmonary Vessels Based On Multi-slice Spiral CT In The Assessment Of Pulmonary Hypertension

Part one:Pulmonary hypertension parameters assessment by multi-slice spiral computed tomography:Normal limits by age,gender,and body surface areaPurpose:Pulmonary hypertension(PH)parameters such as pulmonary artery or right ventricular size that are easily measured on computed tomography(CT).However,there are limited data on electrocardiographically(ECG)-gated CT.We sought to determine age-and gender-specific normal reference values for PH parameters normalized by body surface area(BSA)using ECG-gated cardiac CT and non-ECG-gated cardiac CT.Materials and Methods:In total,we enrolled 519 non-pulmonary hypertension subjects undergoing ECG-gated CT coronary angiography and measured PH parameters,including main pulmonary artery(MPA)and right pulmonary artery(RPA)diameters and distension,ratio of MPA to ascending aorta diameter(MPA/AAO),and ratio of right ventricular to left ventricular diameter(RV/LV).Maximum MPA and RPA diameters also were normalized to BSA(n MPA,n RPA).ECG-gated CT coronary angiography and non-ECG-gated CT were performed in 279patients suspected of having coronary artery disease.Maximum and minimum MPA,RPA and AAO diameters were measured on the end-diastolic and end-systolic phase of pulmonary artery with electrocardiographic-gated CT.Mean MPA and RPA measurements were also obtained in this study.Correlation between ECG-gated CT coronary angiography and non-ECG-gated CT parameters were explored.Further validation of the correlation between the electrocardiographic-gated and non-electrocardiographic-gated CT was performed by using linear regression,respectively.Results:Age,gender,and BSA were varying associated with PH parameters.Age was an independent predictor of all PH parameters.Maximum MPA diameter(26.5±2.7 mm),maximum RPA diameter(20.9±3.0 mm),n MPA(15.8±2.0 mm/m~2),n RPA(12.4±2.0 mm/m~2),and RV/LV(0.85±0.11)increased with age.MPA/AAO(0.80±0.10),MPA and RPA distension(25.4%±7.1%;23.3%±6.7%)negatively correlated with age.Although absolute MPA and RPA diameters were slightly larger in males,females had significantly larger n MPA and n RPA values.MPA and RPA sizes and RV/LV were positively correlated with BSA.There was a significant difference in maximum and minimum pulmonary artery diameters between ECG-gated CT coronary angiography and non-ECG-gated CT,while mean pulmonary artery measurements showed no statistically difference.The correlation of the electrocardiographic-gated CT measurements showed a strong positive correlation with non-electrocardiographic-gated CT,which was confirmed in the validation data set.Conclusions:Using ECG-gated cardiac CT,we determined normal reference values of PH parameters for non-pulmonary hypertension adult subjects,and these values were variably influenced by age,gender,and BSA.There was a significant difference in pulmonary artery size between ECG-gated CT coronary angiography and non-ECG-gated CT.ECG-gated CT measurements demonstrate a high level of correlation with non-ECG-gated CT.Part two: Multi-slice spiral computed tomography measurement of pulmonary artery for diagnosis of COPD and its comorbidity pulmonary hypertension Purpose: We sought to determine the value of MSCT measurement of pulmonary artery size for the diagnosis of chronic obstructive pulmonary disease(COPD)and its comorbidity pulmonary hypertension(PH).Materials and Methods: A total of 221 patients with COPD and 115 control patients without lung or cardiovascular diseases were enrolled in this study.According to pulmonary artery systolic pressure(s PAP)evaluted by echocardiography,the COPD patients were divided into PH(COPD-PH)and non-PH-COPD.Right pulmonary artery(RPA),lain pulmonary artery(LPA),main pulmonary artery(MPA),and ascending aorta(AAO),descending aorta diameters(DAO)were measured.And then,MPA/AAO and MPA/DAO were calculated.Results: MPA,LPA,RPA,MPA/AAO and MAP/DAO were significantly larger in COPD and COPD-PH groups than those in the controls.MPA could be applied to COPD diagnosis(MPA diameter ? 27.5 mm,sensitivity 54%,specificity 80%),and RPA could be helpful for COPD-PH diagnosis(RPA diameter ? 23.4 mm,sensitivity 67%,specificity 76%).There was a positive correlation between MPA/DAO and s PAP(r = 0.594,P ? 0.001),indicating that MPA/DAO could better reflect the changes of pulmonary artery pressure.Conclusions: The measurement of MPA and RPA,and calculating ratio of MPA/DAO on MSCT could be effective and simple modality for diagnostic evaluation of COPD and its comorbidity PH.Part three: The application value of the small pulmonary vessels alteration with multi-slice CT in the evaluation of the severity of COPD and its comorbidity pulmonary hypertension Purpose: To investigate the application value of the percentage of the total cross-sectional area(CSA)of small pulmonary vessels for the lung area(%CSA)and in evaluating the chronic obstructive pulmonary disease(COPD)severity,the occurrence of acute exacerbation of COPD(AECOPD)and its comorbidity pulmonary hypertension by using multi-slice CT(MSCT).Materials and Methods: 166 patients diagnosed with COPD and 166 normal subjects underwent multi-slice chest CT scans.The percentage of the total CSA less than 5 mm2 and 5-10mm2 for the lung area(%CSA?5 and %CSA5-10)were measured with Image J image-processing programand calculated respectively.COPD patients underwent pulmonary function tests(PFT),such as the forced expiratory volume in one second of predicted value(FEV1%)and FEV1/forced vital capacity(FEV1/FVC).They were classified into mild,moderate,severe groups according to FEV1%.They were also classified into two groups according to the information whether experienced AECOPD last year.The mean pulmonary artery pressure(m PAP)was measured by echocardiography.If m PAP?36 mm Hg,PH was diagnosed.Then,123 patients with COPD were divided into PH and non-PH groups.Comparisons of %CSA?5 and %CSA?5-10 between the two groups and different COPD severities were carried out.The correlation between %CSA and PFT was evaluated.Receiver operating characteristic(ROC)curve was generated to calculate the sensitivity and specificity of %CSA for AECOPD.The correlation between m PAP and %CSA in COPD group was verified by Spearman correlation coefficient.Results: The %CSA?5 was lower in COPD patients((0.58±0.18)%)compared with the control group((0.85±0.15)%)(t=12.80,P?0.001).The mean values of %CSA?5 in different groups of severity were((0.77±0.15)%),((0.61±0.15)%)and((0.42±0.11)%)respectively(mild group,32 patients;moderate group,65 patients;severe group,69 patients),and increased severity of COPD was associated with lower %CSA?5(P?0.001).The mean %CSA?5 had a positive correlation with FEV1% and FEV1/FVC(r=0.609,P?0.001;r=0.721,P?0.001)in COPD patients.In addition,it could reflect the occurrence of COPD and AECOPD and the cut-off values were 0.66% and 0.56%(sensitivity,88% and 86%;specificity,73% and 71%)respectively.The AUC values are 0.8893 and 0.764 respectively.The %CSA?5 in COPD with PH were smaller than that in non-PH groups(t=-3.269,P?0.01).The %CSA?5 was negatively correlated with m PAP in COPD groups(r=-0.327,P=0.012).Conclusions: The measurement of %CSA?5 using MSCT scans was significantly lower in COPD patients than control group and positively correlated with PFT.It decreased with the increasing of the severity degree of COPD.It may play an important role in evaluating the severity of COPD.The measurement of %CSA?5 using MSCT scans could not only reflect the degree of COPD severity,but also the occurrence of AECOPD.The quantification of %CSA?5 based on MSCT was significantly different between COPD patients with and without PH.