Deformation analysis of surface and bronchial structures in intraoperative pneumothorax using deformable mesh registration.

The positions of nodules can change because of intraoperative lung deflation, and the modeling of pneumothorax-associated deformation remains a challenging issue for intraoperative tumor localization. In this study, we introduce spatial and geometric analysis methods for inflated/deflated lungs and discuss heterogeneity in pneumothorax-associated lung deformation. Contrast-enhanced CT images simulating intraoperative conditions were acquired from live Beagle dogs. The images contain the overall shape of the lungs, including all lobes and internal bronchial structures, and were analyzed to provide a statistical deformation model that could be used as prior knowledge to predict pneumothorax. To address the difficulties of mapping pneumothorax CT images with topological changes and CT intensity shifts, we designed deformable mesh registration techniques for mixed data structures including the lobe surfaces and the bronchial centerlines. Three global-to-local registration steps were performed under the constraint that the deformation was spatially continuous and smooth, while matching visible bronchial tree structures as much as possible. The developed framework achieved stable registration with a Hausdorff distance of less than 1 mm and a target registration error of less than 5 mm, and visualized deformation fields that demonstrate per-lobe contractions and rotations with high variability between subjects. The deformation analysis results show that the strain of lung parenchyma was 35% higher than that of bronchi, and that deformation in the deflated lung is heterogeneous.

Re-expansion Pulmonary Edema after Chest Tubing: A Case Report / 대한구급학회지

Re-expansion pulmonary edema (RPE) is a rare complication associated with the treatment of collapsed lung caused by pneumothorax, atelectasis, pleural effusion in which a large amount of air or effusion fluid is evacuated. In general RPE is resulted from more than 3 days of lung collapse and application of high negative intrapleural pressure. However, it is reported that RPE could be developed despite the collapse period is short and negative pressure suction is not performed. It also has been known that the rate of reexpansion is more important than amount of evacuated air, or collapse period in the development of RPE. Seventeen-year-old female was undergone suture hemostasis for liver laceration, in which RPE was occurred after closed thoracostomy for pleural effusion on postoperative-27 day. We present a case report with review of related articles.