Air in the Pleural Cavity Enhances Detection of Pleural Abnormalities by CT Scan

Detection of pleural abnormalities on CT scan is critical in diagnosis of pleural disease. CT scan detects minute parenchymal lung nodules, but often fails to detect similar-sized pleural nodularity. This is likely because the density of the visceral/parietal pleura and pleural fluid is similar. We hypothesize that an air-pleural interface enhances detection of pleural abnormalities. We describe six patients with pleural abnormalities that were not (or barely) detected on initial CT scan. However, pneumothorax (either ex vacuo or from a genuine air leak) after pleural fluid drainage permitted the visualization of small pleural abnormalities on CT scan, which would be amenable to imaging-guided biopsies. This case series provides proof-of-principle evidence that the sensitivity of CT scan detection of pleural abnormalities is dependent on adjacent tissue density and can be enhanced by intrapleural air. Future studies of the potential for artificial pneumothorax to improve the diagnosis of pleural disease are warranted.