High-resolution CT findings of miliary pulmonary tuberculosis

This study was performed to identify the characteristic findings of miliary pulmonary tuberculosis on HRCT and to evaluated the usefulness of HRCT by comparison with chest radiographs. High resolution CT, chest radiographs and medical records were retrospectively reviewed in 10 patients with miliary pulmonary tuberculosis. We analysed the size, distribution and margin of nodules, reticular or ground-glass density, parenchymal lesion, mediastinal lymphadenopathy and pleural effusion on HRCT which were compared with chest radiographic findings. On HRCT, characteristic 1-2 mm sized sharp or ill-defined nodular densities were randomly distributed throughout both lungs in all cases. In seven cases, the nodules were evenly scattered, but slightly more in upper lung zone in two cases, and in lower in one case. Only three cases revealed somewhat large and abundant nodules in posterior lung zone. There were findings of ill-defined margin of nodules in three cases, reticular densities in three cases and ground-glass opacity in two cases, all of which were observed within 4 weeks after onset of symptom. In one case, HRCT scan revealed a micronodular pattern in the lung parenchyma, even though chest radiographs of 2 days before were not obviously abnormal. HRCT was better to evaluate the margin of nodule and distribution than chest radiographs in four cases. Focal parenchymal lesion (n = 5), pleural effusion (n = 4), mediastinal lymphadenopathy (n = 6) and ARDS (n = 1) were also associated. HRCT could suggest a more specific diagnosis of miliary pulmonary tuberculosis with the above characteristic findings in appropriate clinical setting and normal or interstitial pattern of chest radiographs