Objective: To assess the utility of CT in the evaluation of pulmonary tuberculosis in patients without AIDS.
Patients and methods: Thin-section CT scans for suspicion of pulmonary tuberculosis were obtained from 226 patients. A total of 38 patients were excluded; the reasons were unavailability of final results (n=18), patient unavailability for follow-up (n=13), and coexistence of tuberculosis and aspergilloma (n=7). The results from 188 patients were used for this study. After assessing the patterns of parenchymal lesion, involved segments, and presence of cavity, bronchiectasis, and bronchogenic spread of the lesion with CT, tentative diagnosis and disease activity were recorded.
Results: With CT, 133 of 146 patients (91%) with tuberculosis were correctly diagnosed as having pulmonary tuberculosis whereas 32 of 42 patients (76%) without tuberculosis were correctly excluded. CT diagnosis of lung cancer (n=8), bacterial pneumonia (n=2), pulmonary metastasis (n=1), chronic hypersensitivity pneumonia (n=1), and diffuse panbronchiolitis (n=1) turned out to be tuberculosis. Conversely CT diagnoses of tuberculosis appeared pathologically as lung cancer (n=5), bacterial pneumonia (n=4), and pulmonary paragonimiasis (n=1). Active (71/89, 80%) and inactive state (51/57, 89%) of disease respectively could be correctly differentiated by CT.
Conclusion: CT can be helpful in the diagnosis of pulmonary tuberculosis in most cases. On the basis of CT findings, distinction of active from inactive disease can be made in most cases.