Pulmonary tuberculosis and Mycobacterium avium-intracellulare: A comparison of CT findings

PURPOSE: To compare the computed tomographic (CT) findings of tuberculosis and Mycobacterium avium-intracellulare (MAI) infection in immunocompetent patients. MATERIALS AND METHODS: Seventy-seven consecutive immunocompetent patients with culture-proved pulmonary mycobacterial infection (45 with pulmonary tuberculosis, 32 with MAI) underwent thin-section CT. CT scans were randomized and reviewed by two observers; decisions were reached by consensus. RESULTS: Micronodules, consolidation, and cavity formation in the lung were seen with similar frequency in pulmonary tuberculosis and MAI cases. Twenty-three patients (51%) with tuberculosis and four patients (12%) with MAI had interlobular septal thickening (P < .001). Twelve patients (27%) with tuberculosis and 30 patients (94%) with MAI had bronchiectasis (P < .001). Bronchiectasis was seen in a mean of 4.6 ± 1.8 and 1.8 ± 1.6 lobes (± standard deviation) in each patient with MAI and with tuberculosis, respectively (P < .01). CONCLUSION: Although CT findings of pulmonary tuberculosis and MAI are similar, interlobular septal thickening is more common in patients with tuberculosis and bronchiectasis is more common and more extensive in patients with MAI.