Purpose: We evaluated the relation between the severity of idiopathic pulmonary fibrosis (IPF) and the incidence of pneumothorax on computed tomography (CT) images.
Materials and methods: In this retrospective study, we evaluated the presence of pneumothorax in 56 consecutive patients who died of IPF from the initial CT to death. We quantitatively analyzed a total of 207 CT images and measured the volume of the normal pattern (N-pattern) and each lesion pattern on the initial CT and their serial changes. The effects of pneumothorax and clinical and CT features on survival were evaluated using Cox regression analysis.
Results: Pneumothorax occurred in 17 of 56 patients. Comparison of the pneumothorax (+) and (-) groups showed the initial vital capacity (VC) was lower (P = 0.005) and the follow-up period was shorter (P = 0.03) in the former group. The decrease in the N-pattern volume in the pneumothorax(+) group was significantly faster than in the pneumothorax(-) group (P = 0.013). Cox regression analyses identified a rapid decrease in N-pattern volume (P = 0.008) and a rapid decrease in VC (P = 0.002), but not pneumothorax, as significant predictors of poor survival.
Conclusion: Pneumothorax in IPF patients is associated with lower VC and rapid deterioration of CT findings. The findings suggest that pneumothorax is a complication of advanced IPF.