CT findings in apical versus basal involvement of pulmonary tuberculosis

We aimed to compare clinical features and computed tomography (CT) findings of pulmonary tuberculosis (TB) in lower lobe basal segments and upper lobe apical or apicoposterior segments.

We retrospectively reviewed medical records and chest CT scans of 986 adults who were diagnosed with active pulmonary TB. Active pulmonary TB confined to the basal segments was found in 21 patients. Sixty patients had disease localized to the apical or apicoposterior segments only. Clinical features and CT abnormalities of the lung parenchyma, airways, mediastinal and hilar lymph nodes, and pleura were compared between these two groups.

A significant difference was observed between two groups in terms of underlying disease prevalence associated with an immunocompromised state (basal, 6/21, 28.6%; apical or apico- posterior, 3/60, 5%; P = 0.008). Chest CT findings, including consolidation (P = 0.0016), lymphadenopathy (P = 0.0297), and pleural effusion (P = 0.008), were more common in basal segment TB than in apical or apicoposterior segment TB. Small nodules were less common in basal segment TB than in apical or apicoposterior segment TB (P = 0.0299). The tree-in-bud sign was the most common CT finding in both basal segment TB (17/21, 81%) and apical or apicoposterior segment TB groups (53/60, 88.3%) (P = 0.4633).

Lower lobe basal segment TB was more commonly present with common CT findings of primary pulmonary TB including consolidation, mediastinal and hilar lymphadenopathy, and pleural effusion than apical or apicoposterior segment TB.