| BackgroundIn 2010,the fifth national epidemiological survey in China showed that the prevalence morbidity rate of active pulmonary tuberculosis was 459/100,000 for people over 15 years old,the prevalence morbidity rate of sputum smear pulmonary tuberculosis was 66/100,000,the prevalence morbidity rate of culture-positive pulmonary tuberculosis was 119/100,000.Pulmonary tuberculosis has brought serious challenges to the prevention and control work.Imaging plays an important role in the diagnosis of pulmonary tuberculosis,and that is an important means of its differential diagnosis,especially with applying the latest version of the<WS288-2017 Diagnosis for Pulmonary Tuberculosis>in the clinic.In particular,for the diagnosis of pulmonary tuberculosis of negative sputum for tuberculous bacterium,it is necessary to combine the clinical symptoms with the images to determine whether the diagnosis is established.Because of its faster scanning speed and higher image resolution,MSCT can clearly display the image characteristics of pulmonary tuberculosis and provide the necessary scientific basis for clinical treatment.In previous studies,the number of pulmonary tuberculosis of positive and negative sputum for tuberculous bacterium was small,and most of them did not distinguish whether they had been treated,the diagnosis and antidiastole of pulmonary tuberculosis of positive and negative sputum for tuberculous bacterium were often carried out through the imaging morphological characteristics of the lesions and the characteristics of the contrast-enhanced lesions,such as "tree-in-bud"sign,ground glass opacity,lobular consolidation,spherical or mass lesion,and segmental consolidation,which rarely involved the distribution of lesions.Even if the distribution of the lesions was researched in the few studies,which was limited to pulmonary lobe,so the distribution of pulmonary tuberculosis was not evaluated very well,especially tuberculosis occured in a certain pulmonary segment.The purpose of this study was to obtain CT manifestations by analyzing the CT thin-layer images or HRCT images in the adult patients of pulmonary tuberculosis of positive and negative sputum for tuberculous bacterium,and to analyze the distribution of these signs in the pulmonary segments,and to find the differences of CT manifestation and distribution in the two groups,so as to provide more proof for the qualitative diagnosis of positive pulmonary tuberculosis and bacterial negative pulmonary tuberculosis,and to improve the diagnostic accuracy.Methods1 PatientsThe adult pulmonary tuberculosis patients who were treated in Shandong Chest Hospital from December 2017 to June 2019 were selected.After being confirmed by clinic and laboratory,the data were complete and patients who had not be treated met the selection criteria of active secondary pulmonary tuberculosis(excluding bronchial tuberculosis and pleura tuberculosis).A total of 500 patients were enrolled.There were 221 cases of pulmonary tuberculosis of positive sputum for tuberculous bacterium and 279 cases of pulmonary tuberculosis of negative sputum for tuberculous bacterium.The other types of tuberculosis or retreated tuberculosis,diabetes,immune-related diseases and other pulmonary diseases were excluded,such as pneumonia,tumor,chronic obstructive pulmonary disease,bronchial asthma,etc.2 CT Protocols and Reconstruction MethodsAll patients were performed using a 128-slice CT(PHILIPS,ingenuity core 128).Under the condition of maximum inspiratory state,the whole lung was scanned according to CT parameters.They were followed:tube voltage of 120kV;tube current of 250mA;scanning field of view,400mm;collimation 0.625 mm×64;pitch,1.08:1;layer thickness and interval of 5mm.Enhanced CT scanning was performed with conventional non-ionic iodine contrast agent(350mgl/ml),intravenous injection at an injection rate of 2.5?4.0ml/s,an injection dose of 80?90ml,and scan time of 30s and 60s after injection,respectively.After scanning,the images of all patients were reconstructed with layer thickness and interval 1mm.The image matrix was 512x512.The lung window settings were a width of 1,400HU and a center of-700HU,while the mediastina window settings were a width of 360HU and a center of 60HU.The thin layer raw data of all patients were uploaded to Philips Extended Brilliance v4.5 workstation.3 Imaging AnalysisCT images were assessed by two radiologists.According to the anatomical site of lung,the both lungs were divided into 18 segments.The features of CT image and the corresponding distributions of lung were recorded of all patients in this study.CT signs of lesion were alveolar nodule,"tree-in-bud" sign,large nodule,lobular consolidation,subsegmental consolidation,segmental consolidation,spherical or mass lession,ground glass opacity,cavity,interstitial abnormalities and bronchiectasis.According to the statistics of CT signs,"yes" is 1,"none" is 0,multiple signs which occured in the same pulmonary can be cumulated.4 Statistical AnalysisSPSS(version 17.0)software was used for statistical analysis.The measurement data were expressed as(x±s),and the t-test was used.The counting data were expressed as percentage(%),and the Chi-squared test was used.The multiple correspondence analysis was carried out based on the gender,CT signs and the distributions of the lesions in this group s patients.The CT signs and distribution of pulmonary tuberculosis of positive sputum for tuberculous bacterium and pulmonary tuberculosis of negative sputum for tuberculous bacterium were classified and analyzed by using the method of clustering analysis.After establishing logistic regression model,the sensitivity and specificity of CT in the diagnosis of the positive pulmonary tuberculosis were analyzed by ROC curve.P<0.05 was considered statistically significant.Results1 CT Signs and Distributions of The Pulmonary Tuberculosis of Positive and Negative Sputum for Tuberculous BacteriumThe morphological features of alveolar nodule were 2?10mm ground glass high density nodule or soft tissue density nodule,which were distributed in clusters.The"tree-in-bud" sign appeared as the centrilobular nodules and the branch line-like shadow associating with it.The nodules showed round,circular and elliptical high-density nodules,and the diameter was 10?30mm.Consolidation was a high-density lesion that covers the normal lung texture on the lung window,and a lesion similar to the density of the large vessels in the mediastinum on the mediastinal window.It can be divided into lobular,subsegmental and segmental consolidation according to the anatomical position.The diameter of spherical or mass lesion was>3cm,the contrast-enhanced CT scanning showed that ring enhancement and inhomogeneous enhancement.Ground glass opacity showed increased density of lung window,but the bronchovascular bundles could still be displayed,and could not be displayed on mediastinal window images.The cavities were divided into thick walled cavities(wall thickness>3mm),thin walled cavities(wall thickness?3mm)and"wormlike" cavities(that is,the inner edge is smooth and there is no "wall" cavity).Interstitial abnormalities showed large patches of irregular reticulation shadow,linear high density shadow,inhomogeneous patchy or flake ground glass opacity shadow,blurred lobular structure,"cuff sign" or "track sign" and blurred edge around bronchial vascular bundles.Bronchiectasis showed the change of the lumen which was larger than the normal diameter.It could be shown as cystic,columnar and varicose dilation.Alveolar nodule,"tree-in-bud" sign,nodules,lobular consolidation,subsegmental consolidation,segmental consolidation,spherical or mass lesion,ground glass opacity,cavity,interstitial abnormalities and bronchiectasis could be found in 364 patients(156 cases of positive pulmonary tuberculosis,208 cases of negative pulmonary tuberculosis),335 patients(175 cases of positive pulmonary tuberculosis,160 cases of negative pulmonary tuberculosis),294 patients(145 cases of positive pulmonary tuberculosis,149 cases of negative pulmonary tuberculosis),443 patients(199 cases of positive pulmonary tuberculosis,244 cases of negative pulmonary tuberculosis),146 patients(65 cases of positive pulmonary tuberculosis,81 cases of the negative pulmonary tuberculosis),81 patients(51 cases of positive pulmonary tuberculosis,30 cases of negative pulmonary tuberculosis),43 patients(24 cases of positive pulmonary tuberculosis,19 cases of negative pulmonary tuberculosis),212 patients(123 cases of positive pulmonary tuberculosis,89 cases of negative pulmonary tuberculosis),175 patients(133 cases of positive pulmonary tuberculosis,42 cases of negative pulmonary tuberculosis),153 patients(55 cases of positive pulmonary tuberculosis,98 cases of negative pulmonary tuberculosis),101 patients(61 cases of positive pulmonary tuberculosis,40 cases of negative pulmonary tuberculosis),respectively.2 Correspondence Analysis of Active Pulmonary TuberculosisTaking gender,CT signs and the location of the lesions as variables,multiple correspondence analysis map was formed.According to CT signs,there were significantly different in the distribution of interstitial abnormalities,segmental consolidation,bronchiectasis and spherical or mass lession with other lessions.Lobular consolidation and large nodular shadow were common in the S1,S2,S3 of right lung and the S6,S10 of left lung in male.Alveolar nodule and "tree-in-bud" sign were common in the S4 of right lung and the S9 of the left lung in female.3 Clustering Analysis of Various CT Signs in the Pulmonary Tuberculosis of Positive and Negative Sputum for Tuberculous Bacterium11 kinds of CT signs were finally divided into 3 categories in the group of positive pulmonary tuberculosis and divided into 5 categories in the group of negative pulmonary tuberculosis,respectively.18 pulmonary segments were both divided into 5 categories in the pulmonary tuberculosis of positive and negative sputum for tuberculous bacterium.Similar vectors were grouped into one category,with the quantity decreasing step by step.4 Comparison of Various CT Signs Between in the Pulmonary Tuberculosis of Positive and Negative Sputum for Tuberculous Bacterium4.1 Comparison of the incidence of various CT signs between in the pulmonary tuberculosis of positive and negative sputum for Tuberculous BacteriumCompared with CT manifestations in pulmonary tuberculosis of positive and negative sputum for tuberculous bacterium,there were significantly different of the"tree-in-bud" sign,large nodule,segmental consolidation,ground glass opacity,interstitial abnormality and bronchiectasis(?2=26.599,7.584,13.797,28.497,1 10.388,6.087,13.461,respectively;P<0.05).There was significant difference between thick-wall cavity and thin-wall cavity(?2=30.2576,26.4727,P<0.05).4.2 Comparison of the morphology of cavity in genderIn gender,thick-wall cavity was more likely to occur in the positive pulmonary tuberculosis of male patients(P<0.05),but there was no difference in gender between thin-wall cavity and no-wall cavity(P>0.05).4.3 Comparison of various CT signs between the two groups of pulmonary segmentsThe number of the pulmonary segments which were involved in the positive pulmonary tuberculosis and the negative pulmonary tuberculosis were 4277 and 4069 respectively(?2=37.934,P<0.05).There was significant difference in two groups.The cumulative frequencies of various CT signs in the same pulmonary segment between the two groups were significantly different.The pulmonary tuberculosis of positive sputum for tuberculous bacterium was significantly more than the pulmonary tuberculosis of negative sputum for tuberculous bacterium in the S1,S2,S6,S7 of right lung and the S1+2,S3,S6,S10 of left lung(?2=47.513,22.299,36.415,4.645,23.556,27.179,33.157,12.980,respectively,P<0.05).The number of partial CT features in the same pulmonary segment of the two groups was significantly different.5 Logistic Regression AnalysisThe risk factors of the positive pulmonary tuberculosis group were "tree-in-bud'sign,segmental consolidation and cavity,which were analyzed by binary logistic regression analysis(P<0.05).6 ROC CurveThe sensitivity of CT in the diagnosis of positive pulmonary tuberculosis was 87.43%,the specificity was 82.95%,and the Youden index was 0.704.ConclusionsThe CT signs of non-treatment active secondary pulmonary tuberculosis was characterized.The positive pulmonary tuberculosis and negative pulmonary tuberculosis had their own imaging features,and there were some certain identification points between in two groups.The "tree-in-bud" sign,large nodule,segmental consolidation,thick-wall cavity,ground glass opacity and bronchiectasis were more likely to occur in the positive pulmonary tuberculosis of patients,however,interstitial abnormalities and thin-wall cavity were more likely to occur in the negative pulmonary tuberculosis of patients.Combined with CT features and their distributions,which was certain guiding value for the prediction of the positive and negative pulmonary tuberculosis. |
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