CT differentiation of tuberculous and non-tuberculous pleural infection, with emphasis on pulmonary changes.

OBJECTIVE: To determine whether pulmonary changes on computed tomography (CT) are helpful in differentiating between pleural tuberculosis (TB) and non-tuberculous pleural infection

MATERIALS AND METHODS: We retrospectively reviewed CT scans of patients with pleural tuberculous and non-tuberculous empyema, focusing on pulmonary changes such as consolidation, ground glass opacity, interlobular septal thickening, cavitation, abscess and presence and distribution of micronodules. We also assessed the presence of loss of overlying pleural integrity, peripheral bronchopleural fistula and lymphadenopathy.

RESULTS: We evaluated 65 patients with pleural TB and 43 with empyema. CT findings of pleural TB differed significantly from those of empyema with interlobular septal thickening (P = 0.022) and micronodules with subpleural, peribronchovascular and septal distribution (P < 0.001). Subpleural abscess was more frequently seen in empyema, accompanying loss of overlying pleural integrity and peripheral bronchopleural fistula (P < 0.001), but there was no statistical difference between the two groups in prevalence of consolidation, ground glass opacity, cavitation, centrilobular nodules or lymphadenopathy.

CONCLUSION: Interlobular septal thickening and micronodules with perilymphatic distribution are characteristic CT findings of pleural TB but not empyema. Presence of subpleural abscess and loss of pleural integrity or peripheral bronchopleural fistula are highly suggestive of empyema.