Predictors of pneumothorax after transthoracic lung biopsy: The role of quantitative CT

Background: Computerized tomography (CT) guided transthoracic needle lung biopsy is associated with post procedure pneumothorax and hemorrhage. Pulmonary emphysema assessed visually on chest CT is a risk factor for post needle lung biopsy pneumothorax; however, automated quantitative CT assessed emphysema has not been evaluated. Objective: This study aims to evaluate the association of quantitative CT measures of emphysema with the occurrence of pneumothorax after CT-guided needle lung biopsy, accounting for other risk factors. Methods: 163 CT guided needle lung biopsies performed between 2008 and 2013 with available complete chest CT within 30 days were reviewed for the occurrence of post procedure pneumothorax. Percent emphysema was determined quantitatively as the percentage of lung voxels below -950 HU on chest CT scans using automated software. Multivariable regression was used to assess the association of percent emphysema volume with the occurrence of post procedure pneumothorax. The association of percent emphysema volume with the pneumothorax size, need for chest tube placement and hemorrhage after needle lung biopsy was also explored. Results: Percent emphysema was significantly associated with incident post needle lung biopsy pneumothorax (OR=1.10 95%CI [1.01-1.15] p=0.03) adjusting for lower lobe lesion location, needle path length, lesion size, number of passes and pleural needle trajectory angle. Percent emphysema was not associated with the size of the pneumothorax, need for chest tube placement, nor with hemorrhage after needle lung biopsy. Conclusion: Percent emphysema determined quantitatively from chest CT is a significant predictor of post needle lung biopsy pneumothorax.