The Differential Diagnosis In Diffuse Nodular Lung Diseases On HRCT

Objectives:The purpose of this study was to analyze the pulmonary lobular structure and other features on HRCT of pulmonary tuberculosis and lung cancer with diffuse nodular and to assess the value in differential diagnosis.Material and Methods:91 pulmonary tuberculosis and 59 lung cancer cases underwent CT scans; the images were reconstructed using high-spatial-resolution algorithms. Of which 36 patients were also reconstructed through MPR and MIP.12 patients underwent CT-guided percutaneous needle lung biopsy. The pulmonary tuberculosis cases were diagnosed by microbiology and/or histopathology or clinical comprehensive diagnosis, the lung cancer cases were diagnosed by cytopathology and/or histopathology.Results:(1)Pulmonary lymphangitic carcinomatosis exhibited beaded or irregular interlobular septa were 60%(9/15)and 40%(6/15) ,respectively, there were significant difference between which and hematogenous disseminated pulmonary tuberculosis.(P<0.05) Intralobular linear or fine reticular opacities in pulmonary lymphangitic carcinomatosis were 60%(9/15),different from the hematogenous disseminated pulmonary tuberculosis and pulmonary hematogenous metastases and diffuse nodular bronchioloalveolar carcinoma (P<0.05).83.3% bronchogenic pulmonary tuberculosis shows centrilobular nodules and branching linear lesions(tree in bud), significant differences between which and the hematogenous disseminated pulmonary tuberculosis or pulmonary metastases. Most nodules in acute hematogenous disseminated pulmonary tuberculosis were uniform in size, density and distribution, but in pulmonary hematogenous metastases and subacute-chronic hematogenous disseminated pulmonary tuberculosis the nodular size were mostly irregular and some nodular density and distribution of which were uneven. Hilar or mediastinal lymphadenopathy and plural effusion were more frequently visualized in pulmonary lymphangitic carcinomatosis than the acute hematogenous disseminated pulmonary tuberculosis(P<0.05). (2)In showing the presence of pulmonary lobular structure and micronodules and their distribution characteristics ,no significant difference was found in the satisfied degree between the multiplanar reconstruction and volumetric HRCT(P>0.05),and so was between maximum intensity projection and volumetric HRCT(P>0.05).Conclusion:HRCT accurately showing the abnormal features of pulmonary lobular structure ,micronodules and their distribution characteristics and other accompanying findings, had very important value in the differential diagnosis of pulmonary tuberculosis and lung cancer with diffuse micronodules.The HRCT location of nodules in relation to the pulmonary lobule represent the pathology features of diffuse lesion. The reconstruction images of MPR and MIP can display the lesion's morphologic characterization and distribution in different aspects . MPR and MIP images are important added methods of axial HRCT images.