Computed tomography in miliary tuberculosis: comparison with plain films, bronchoalveolar lavage, pulmonary functions and gas exchange.

Computed tomography (CT) of the chest, pulmonary function tests, bronchoalveolar lavage (BAL) and arterial blood gas analysis were performed in 26 patients with non-HIV miliary tuberculosis (MTB). CT was repeated after treatment in 11 patients. Nodular lesions were characteristically seen on CT. CT showed discrete and fine nodules in five patients in whom the lesions appeared to be larger than miliary on chest X-rays. Coalescing nodular lesions were noted on chest X-rays (n = 7) and CT (n = 18). Consolidation (n = 6), cavitation (n = 4), fibrosis (n = 9) and air trapping (n = 14) were detected on CT only. During follow up, air trapping increased (n = 14) and in some patients it appeared for the first time (n = 2). Lymph node enlargement and calcification were seen on both chest X-rays (n = 9 and n = 3, respectively) and CT (n = 12 and n = 7, respectively). Pleural involvement was also seen in chest X-rays (n = 4) and CT (n = 5). Total lung capacity was higher in patients with a chest X-ray score > 10. Similarly a higher total cell count in BAL fluid was observed in patients with a CT score > 10. It is concluded from this study that CT is superior to chest X-rays in detecting nodular lesions, lymphadenopathy and air trapping in patients with MTB.