Background: The objective of this study was to evaluate pulmonary abnormalities of pleural TB by CT scanning and to determine CT scan findings for the development of the paradoxical response (PR).
Methods: CT scans were performed for 349 patients with pleural TB (between 2008 and 2013). We excluded 34 patients with coexisting pulmonary disease (n 5 13) or a totally collapsed lung (n 5 21). We analyzed CT scans focusing on pulmonary abnormalities such as the presence of consolidation, cavitation, interlobular septal thickening, and micronodules and their distribution. In addition, we recorded the development of PR during follow-up and statistically analyzed differences in clinical and CT scan findings between patients with and without PR.
Results: A total of 270 of 315 patients (86%) had pulmonary abnormalities. Common CT scan findings were micronodules (n 5 209 [77%]), interlobular septal thickening (n 5 202 [75%]),and consolidation (n 5 120 [44%]). Cavitation was seen in 49 patients (18%). Among 209 with micronodules, the nodules were in the subpleural region (n 5 146 [70%]), peribronchovascular interstitium (n 5 113 [54%]), and centrilobular region (n 5 64 [31%]). PR occurred in 81 patients(26%), and patients with PR tended to be young, male, and without underlying disease ( P , .05 by t test, Pearson x 2 test). Subpleural micronodules were more common in patients with PR than in those without PR (Pearson x 2 , P 5 .025).
Conclusions: Pulmonary abnormalities are very common in pleural TB. Th e most common CT scan findings were micronodules in the subpleural and peribronchovascular interstitium and interlobular septal thickening, suggesting the lymphatic spread of TB. In addition, PR is not rare in patients with pleural TB, especially in young, previously healthy, male patients who show subpleural nodules on initial CT scans.