Analysis of Chest CT in Patients with Mycobacterium avium Complex Pulmonary Disease

Background: The radiographic changes of Mycobacterium avium complex (MAC) pulmonary disease during therapy have not been studied well. Objective: To assess the efficacy of antituberculous drug therapy against MAC pulmonary disease using computed tomography (CT). Method: We analyzed chest CT scans before and after antituberculous therapy in 30 patients (21 women, 9 men) with MAC pulmonary disease. To evaluate radiographic changes during therapy, we defined a ‘degree of improvement’ (DI) that is calculated according to the CT appearance. Results: DI was better (1.35 ± 0.21) in patients who had converted sputum culture than in those who had not (0.44 ± 0.25) (p < 0.05). In patients who were diagnosed by bronchial washing, DI was better (1.60 ± 0.22) than in patients who were diagnosed by sputum (0.67 ± 0.20) (p < 0.01). We categorized the CT appearance into 6 types: small nodules, cavities, bronchial wall thickening, infiltration, pleural thickening and atelectasis. Patients who showed pleural thickening had a significantly worse DI (0.12 ± 0.40) than those who did not (1.23 ± 0.18) (p < 0.01). Most of the lesions that disappeared after therapy were small nodules. Conclusion: These results indicate that chest CT might be a useful tool for the prediction or assessment of drug therapy for MAC pulmonary disease.