Mycobacterium tuberculosis versus nontuberculous mycobacterial infection of the lung in AIDS patients: CT and HRCT patterns

Purpose: The aim of this study was to determine discriminating CT and HRCT features between mycobacterial pulmonary tuberculosis and nontuberculous mycobacterial (NTMB) pulmonary infections in patients with AIDS. Method: CT and HRCT scans of 52 AIDS patients with culture-proven mycobacterial infection [29 with Mycobacterium tuberculosis (MTB) and 23 with NTMB] without concomitant pulmonary infection were reviewed by two observers. Results: Nodular opacities, mainly centrilobular in distribution, were the most common finding, seen in 21 (72%) and 15 (65%) of patients with MTB and NTMB, respectively. A lower lobe predominance of centrilobular nodules was seen more commonly in NTMB (p < 0.03). Ground-glass attenuation was seen in 5 (17%) and 11 (48%) of patients with MTB and NTMB, respectively (p = 0.03). Ground-glass opacities and bronchial wall thickening affected a larger number of lobes in NTMB (p < 0.01), while centrilobular nodules involved more lobes in MTB (p < 0.01). A higher prevalence of unilateral lung involvement was seen in MTB (12 patients, 44%) than NTMB (1 patient, 5%) (p < 0.01). Enlarged lymph nodes were more frequent in patients with MTB than in those with NTMB (22, 76% vs. 10, 43%, respectively) (p < 0.02). Conclusion: NTMB infection and pulmonary tuberculosis display different CT and HRCT patterns in AIDS patients, but there is considerable overlap in CT findings.