[Role of computerized tomography in the study of pulmonary tuberculosis]

We carried out a retrospective study on 4 years' work on a series of patients with proved active tuberculosis examined in the Departments of Bronchopneumology and Infectious Diseases of the Arezzo Civil Hospital. The population was heterogeneous from the immunologic viewpoint. We compared the effectiveness of Computed Tomography (CT) with that of conventional chest radiography (CR) in the diagnosis and prognosis of tuberculosis. Thirty-eight patients were examined and subdivided into three groups according to their normal/altered immunologic state: 24 of them were thus considered immunocompetent and 9 immunodeficient; 5 patients were immigrants, with different immunologic susceptibility from European men. All patients underwent chest CR in double projection and conventional CT studies of the chest; 16 patients were also submitted to high resolution CT (HRCT). Consolidation was the most frequent parenchymal lesion in immunocompetent patients (10 of 24 cases); it was often associated with cavitation (9 of 10 cases), with no clear topographic prevalence in the upper lobes. Pleural effusion, as the only sign of disease and with empyema features, was found in 10 immunocompetent patients. No predominant pattern was found in the other two groups, even though intrathoracic adenopathies were relatively more common in the immigrants (4 cases) while micronodular images (5 cases) and cavitations (5 cases) were more common in the immunodeficient subjects. Finally, chest CR always depicted the signs of pneumopathy in progress. Conventional CT was more accurate in the spatial definition of pleuroparenchymal lesions and demonstrated more nodular lesions (6 cases with CR versus 10 cases with CT) and/or infiltrating lesions (6 cases with CR versus 15 with CT) which were often masked by scars, by massive pleural effusions or by calcific fibrothorax. CT also demonstrated adenopathic mediastinal involvement (7 cases with CR versus 11 with CT), showed empyemic pleural collections and confirmed fistulas in calcific fibrothorax subjects. Moreover, HRCT depicted centrilobular micronodular images which are often ill-defined and poorly or not recognizable at CR but are signs of tuberculous infection spread along the distal airways. Posttreatment follow-up confirmed clinical recovery showing markedly and progressively fewer small nodular densities.