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Jonas Alexander Leppig,1 Lan Song,2 Dorothea C Voigt,1 Felix W Feldhaus,1 Christoph Ruwwe-Gloesenkamp,3 Jacopo Saccomanno,3 Bianca C Lassen-Schmidt,4 Konrad Neumann,5 Katja Leitner,6 Ralf H Hubner,3 Felix Doellinger1 1Department of Radiology, Charité Universitätsmedizin Berlin, Berlin, Germany; 2Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People’s Republic of China; 3Department of Internal Medicine/Infectious Diseases and Respiratory Medicine, Charité Universitätsmedizin Berlin, Berlin, Germany; 4Fraunhofer Institute for Digital Medicine MEVIS, Bremen, Germany; 5Institute of Biometrics and Clinical Epidemiology, Charité Universitätsmedizin Berlin, Berlin, Germany; 6Department of Internal Medicine, Kantonsspital Aarau AG, Aarau, SwitzerlandCorrespondence: Jonas Alexander Leppig, Department of Radiology, Charité Universitätsmedizin Berlin, Charité Campus Virchow-Klinikum, Augustenburger Platz 1, Berlin, 13353, Germany, Tel + 49 30 450 627 283, Fax + 49 30 450 527 911, Email Jonas-Alexander.Leppig@charite.dePurpose: To investigate changes in quantitative CT analysis (QCT) and pulmonary function tests (PFT) in pulmonary emphysema patients who required premature removal of endobronchial valves (EBV).Patients and Methods: Our hospital’s medical records listed 274 patients with high-grade COPD (GOLD stages 3 and 4) and pulmonary emphysema who were treated with EBV to reduce lung volume. Prior to intervention, a complete evaluation was performed that included quantitative computed tomography analysis (QCT) of scans acquired at full inspiration and full expiration, pulmonary function tests (PFT), and paraclinical findings (6-minute walking distance test (6MWDT) and quality of life questionnaires). In 41 of these 274 patients, EBV treatment was unsuccessful and the valves had to be removed for various reasons. A total of 10 of these 41 patients ventured a second attempt at EBV therapy and underwent complete reevaluation. In our retrospective study, results from three time points were compared: Before EBV implantation (BL), after EBV implantation (TP2), and after EBV explantation (TP3). QCT parameters included lung volume, total emphysema score (TES, ie, the emphysema index) and the 15th percentile of lung attenuation (P15) for the whole lung and each lobe separately. Differences in these parameters between inspiration and expiration were calculated (Vol. Diff (%), TES Diff (%), P15 Diff (%)). The results of PFT and further clinical tests were taken from the patient’s records.Results: We found persistent therapy effect in the target lobe even after valve explantation together with a compensatory hyperinflation of the rest of the lung. As a result of these two divergent effects, the volume of the total lung remained rather constant. Furthermore, there was a slight deterioration of the emphysema score for the whole lung, whereas the TES of the target lobe persistently improved.Conclusion: Interestingly, we found evidence that, contrary to our expectations, unsuccessful EBV therapy can have a persistent positive effect on target lobe QCT scores.Keywords: chronic obstructive pulmonary disease, pulmonary emphysema, endobronchial valves, lung volume reduction, computed tomography, pulmonary function test

Karin Klooster,1,* T David Koster,1,* Christoph Ruwwe-Glösenkamp,2 Dorothea Theilig,3 Felix Doellinger,3 Jacopo Saccomanno,2 Huib AM Kerstjens,1 Dirk-Jan Slebos,1 Ralf-Harto Hübner2 1University of Groningen, University Medical Center Groningen, Department of Pulmonary Diseases, Groningen, the Netherlands; 2Charité Universitätsmedizin Berlin, Campus Virchow Klinikum, Department of Pneumology, Berlin, Germany; 3Charité Universitätsmedizin Berlin, Campus Virchow Klinikum, Department of Radiology, Berlin, Germany*These authors contributed equally to this workCorrespondence: Karin Klooster Email k.klooster@umcg.nlPurpose: Lung volume reduction using one-way endobronchial valves is a bronchoscopic treatment for patients with severe emphysema without collateral ventilation between the treatment target lobe and the ipsilateral lobe(s). CT-scan fissure analysis is often used as a surrogate to predict the absence of collateral ventilation. We aimed to evaluate the predictive value of the fissure completeness score (FCS) compared to the functional Chartis measurement of collateral ventilation and to provide cut-off values of the FCS in patient selection.Patients and Methods: Multicenter study in patients eligible for treatment with one-way valves. The FCS was calculated by quantitative CT analysis (Thirona, the Netherlands) and compared to status of interlobar collateral ventilation measured with Chartis system (PulmonX, USA). Thresholds were calculated for the predictive values of the presence of collateral ventilation.Results: An FCS > 95% of the left major fissure had a positive predictive value (PPV) of 91%, with 1 in 11 fissures demonstrating collateral ventilation with Chartis measurement, whereas an FCS of ≤ 80% had a negative predictive value (NPV) of 100% for the presence of collateral ventilation. For the right major fissure, the NPV was 100% for an FCS ≤ 90%, but 69.7% for the right upper lobe fissure.Conclusion: Quantitative CT analysis is recommended in all patients evaluated for endobronchial valves. Patients with incomplete fissures (left major fissure: FCS < 80%; right major fissure: < 90%) can be excluded from Chartis measurement and endobronchial valve treatment. In patients with more complete fissures, the FCS is not specific enough for endobronchial valve treatment decisions. In this case, additional Chartis measurements are always recommended in the right lung. For the left lung, Chartis assessments may be omitted if the FCS is > 95%.Keywords: COPD, lung volume reduction, fissure, collateral ventilation, CT scan

Felix W Feldhaus,1 Dorothea Cornelia Theilig,1 Ralf-Harto Hubner,2 Jan-Martin Kuhnigk,3 Konrad Neumann,4 Felix Doellinger11Charité Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Department of Radiology, Berlin, Germany; 2Department of Internal Medicine/Infectious and Respiratory Disease, Charité Universitätsmedizin Berlin, Berlin, Germany; 3Institute for Medical Image Computing, Fraunhofer MEVIS, Bremen, Germany; 4Institute of Biometrics and Clinical Epidemiology, Charité Universitätsmedizin Berlin, Berlin, GemanyPurpose: Quantitative analysis of CT scans has proven to be a reproducible technique, which might help to understand the pathophysiology of chronic obstructive pulmonary disease (COPD) and combined pulmonary fibrosis and emphysema. The aim of this retrospective study was to find out if the lung function of patients with COPD with Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages III or IV and pulmonary emphysema is measurably influenced by high attenuation areas as a correlate of concomitant unspecific fibrotic changes of lung parenchyma.Patients and methods: Eighty-eight patients with COPD GOLD stage III or IV underwent CT and pulmonary function tests. Quantitative CT analysis was performed to determine low attenuation volume (LAV) and high attenuation volume (HAV), which are considered to be equivalents of fibrotic (HAV) and emphysematous (LAV) changes of lung parenchyma. Both parameters were determined for the whole lung, as well as peripheral and central lung areas only. Multivariate regression analysis was used to correlate HAV with different parameters of lung function.Results: Unlike LAV, HAV did not show significant correlation with parameters of lung function. Even in patients with a relatively high HAV of more than 10%, in contrast to HAV (p=0.786) only LAV showed a significantly negative correlation with forced expiratory volume in 1 second (r=−0.309, R2=0.096, p=0.003). A severe decrease of DLCO% was associated with both larger HAV (p=0.045) and larger LAV (p=0.001). Residual volume and FVC were not influenced by LAV or HAV.Conclusion: In patients with COPD GOLD stage III-IV, emphysematous changes of lung parenchyma seem to have such a strong influence on lung function, which is a possible effect of concomitant unspecific fibrosis is overwhelmed.Keywords: COPD, quantitative CT, pulmonary fibrosis, pulmonary emphysema, CPFE

Dorothea Theilig,1 Felix Doellinger,1 Alexander Poellinger,1 Vera Schreiter,1 Konrad Neumann,2 Ralf-Harto Hubner31Department of Radiology, Charité Campus Virchow Klinikum, Charité, Universitätsmedizin Berlin, Berlin, Germany; 2Institute of Biometrics and Clinical Epidemiology, Charité Campus Benjamin Franklin, Charité, Universitätsmedizin Berlin, Berlin, Germany; 3Department of Pneumology, Charité Campus Virchow Klinikum, Charité, Universitätsmedizin Berlin, Berlin, GermanyBackground: The degree of interlobar emphysema heterogeneity is thought to play an important role in the outcome of endoscopic lung volume reduction (ELVR) therapy of patients with advanced COPD. There are multiple ways one could possibly define interlobar emphysema heterogeneity, and there is no standardized definition.Purpose: The aim of this study was to derive a formula for calculating an interlobar emphysema heterogeneity index (HI) when evaluating a patient for ELVR. Furthermore, an attempt was made to identify a threshold for relevant interlobar emphysema heterogeneity with regard to ELVR.Patients and methods: We retrospectively analyzed 50 patients who had undergone technically successful ELVR with placement of one-way valves at our institution and had received lung function tests and computed tomography scans before and after treatment. Predictive accuracy of the different methods for HI calculation was assessed with receiver-operating characteristic curve analysis, assuming a minimum difference in forced expiratory volume in 1 second of 100 mL to indicate a clinically important change.Results: The HI defined as emphysema score of the targeted lobe (TL) minus emphysema score of the ipsilateral nontargeted lobe disregarding the middle lobe yielded the best predicative accuracy (AUC =0.73, P=0.008). The HI defined as emphysema score of the TL minus emphysema score of the lung without the TL showed a similarly good predictive accuracy (AUC =0.72, P=0.009). Subgroup analysis suggests that the impact of interlobar emphysema heterogeneity is of greater importance in patients with upper lobe predominant emphysema than in patients with lower lobe predominant emphysema.Conclusion: This study reveals the most appropriate ways of calculating an interlobar emphysema heterogeneity with regard to ELVR. Keywords: CT-quantitative, COPD, emphysema heterogeneity, endoscopic lung volume reduction

Christian Thomsen,1 Dorothea Theilig,2 Dominik Herzog,1 Alexander Poellinger,2 Felix Doellinger,2 Nils Schreiter,3 Vera Schreiter,2 Dirk Schürmann,1 Bettina Temmesfeld-Wollbrueck,1 Stefan Hippenstiel,1 Norbert Suttorp,1 Ralf-Harto Hubner1 1Department of Internal Medicine/Infectious Diseases and Respiratory Medicine, 2Institute of Radiology, 3Institute of Nuclear Medicine, Charité – Universitätsmedizin Berlin, Berlin, Germany Abstract: The exclusion of collateral ventilation (CV) and other factors affect the clinical success of endoscopic lung volume reduction (ELVR). However, despite its benefits, the outcome of ELVR remains difficult to predict. We investigated whether clinical success could be predicted by emphysema distribution assessed by computed tomography scan and baseline perfusion assessed by perfusion scintigraphy. Data from 57 patients with no CV in the target lobe (TL) were retrospectively analyzed after ELVR with valves. Pulmonary function tests (PFT), St George’s Respiratory Questionnaire (SGRQ), and 6-minute walk tests (6MWT) were performed on patients at baseline. The sample was grouped into high and low levels at the median of TL perfusion, ipsilateral nontarget lobe (INL) perfusion, and heterogeneity index (HI). These groups were analyzed for association with changes in outcome parameters from baseline to 3 months follow-up. Compared to baseline, patients showed significant improvements in PFT, SGRQ, and 6MWT (all P≤0.001). TL perfusion was not associated with changes in the outcome. High INL perfusion was significantly associated with increases in 6MWT (P=0.014), and high HI was associated with increases in forced expiratory volume in 1 second (FEV1), (P=0.012). Likewise, there were significant correlations for INL perfusion and improvement of 6MWT (r=0.35, P=0.03) and for HI and improvement in FEV1 (r=0.45, P=0.001). This study reveals new attributes that associate with positive outcomes for patient selection prior to ELVR. Patients with high perfusions in INL demonstrated greater improvements in 6MWT, while patients with high HI were more likely to respond in FEV1. Keywords: endoscopic lung volume reduction, COPD, valves, lung perfusion, emphysema distribution

Background: Previous studies showed that contrast-enhanced (CE) morpho-functional magnetic resonance imaging (MRI) detects abnormalities in lung morphology and perfusion in patients with cystic fibrosis (CF). Novel matrix pencil decomposition MRI (MP-MRI) enables quantification of lung perfusion and ventilation without intravenous contrast agent administration., Objectives: To compare MP-MRI with established morpho-functional MRI and spirometry in patients with CF., Methods: Thirty-nine clinically stable patients with CF (mean age 21.6 ± 10.7 years, range 8-45 years) prospectively underwent morpho-functional MRI including CE perfusion MRI, MP-MRI and spirometry. Two blinded chest radiologists assessed morpho-functional MRI and MP-MRI employing the validated chest MRI score. In addition, MP-MRI data were processed by automated software calculating perfusion defect percentage (QDP) and ventilation defect percentage (VDP)., Results: MP perfusion score and QDP correlated strongly with the CE perfusion score (both r  = 0.81; p  < 0.01). MP ventilation score and VDP showed strong inverse correlations with percent predicted FEV1 ( r  = -0.75 and r  = -0.83; p  < 0.01). The comparison of visual and automated parameters showed that both MP perfusion score and QDP, and MP ventilation score and VDP were strongly correlated ( r  = 0.74 and r  = 0.78; both p  < 0.01). Further, the MP perfusion score and MP ventilation score, as well as QDP and VDP were strongly correlated ( r  = 0.88 and r  = 0.86; both p  < 0.01)., Conclusion: MP-MRI detects abnormalities in lung perfusion and ventilation in patients with CF without intravenous or inhaled contrast agent application, and correlates strongly with the well-established CE perfusion MRI score and spirometry. Automated analysis of MP-MRI may serve as quantitative noninvasive outcome measure for diagnostic monitoring and clinical trials., Competing Interests: MS reports research grants from the German Federal Ministry of Education and Research (BMBF), the German Research Foundation (DFG) and Vertex Pharmaceuticals paid to the institution; personal fees for participation in advisory boards or consulting from Vertex Pharmaceuticals. MW reports research grants from Vertex Pharmaceuticals paid to the institution; consulting fees from Boehringer Ingelheim and Vertex Pharmaceuticals paid to the institution; lecture fees from Vertex Pharmaceuticals paid to the institution. MM reports research grants from the German Federal Ministry of Education and Research (BMBF), the German Research Foundation (DFG) and Vertex Pharmaceuticals paid to the institution; personal fees for participation in advisory boards or consulting from Arrowhead Pharmaceuticals, Boehringer Ingelheim, Enterprise Therapeutics, Kither Biotech, Vertex Pharmaceuticals; lecture fees from Vertex Pharmaceuticals; and travel reimbursement from Boehringer Ingelheim and Vertex Pharmaceuticals. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Doellinger, Bauman, Roehmel, Stahl, Posch, Steffen, Pusterla, Bieri, Wielpütz and Mall.)

Introduction: Prospective and longitudinal data on pulmonary injury over one year after acute coronavirus disease 2019 (COVID-19) are sparse. We aim to determine reductions in pulmonary function and respiratory related quality of life up to 12 months after acute COVID-19., Methods: Patients with acute COVID-19 were enrolled into an ongoing single-centre, prospective observational study and prospectively examined 6 weeks, 3, 6 and 12 months after onset of COVID-19 symptoms. Chest CT-scans, pulmonary function and symptoms assessed by St. Georges Respiratory Questionnaire were used to evaluate respiratory limitations. Patients were stratified according to severity of acute COVID-19., Results: Median age of all patients was 57 years, 37.8% were female. Higher age, male sex and higher BMI were associated with acute-COVID-19 severity (p < 0.0001, 0.001 and 0.004 respectively). Also, pulmonary restriction and reduced carbon monoxide diffusion capacity was associated with disease severity. In patients with restriction and impaired diffusion capacity, FVC improved over 12 months from 61.32 to 71.82, TLC from 68.92 to 76.95, D LCO from 60.18 to 68.98 and K CO from 81.28 to 87.80 (percent predicted values; p = 0.002, 0.045, 0.0002 and 0.0005). The CT-score of lung involvement in the acute phase was associated with restriction and reduction in diffusion capacity in follow-up. Respiratory symptoms improved for patients in higher severity groups during follow-up, but not for patients with initially mild disease., Conclusion: Severity of respiratory failure during COVID-19 correlates with the degree of pulmonary function impairment and respiratory quality of life in the year after acute infection., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The COVID-19 pandemic has worldwide individual and socioeconomic consequences. Chest computed tomography has been found to support diagnostics and disease monitoring. A standardized approach to generate, collect, analyze, and share clinical and imaging information in the highest quality possible is urgently needed. We developed systematic, computer-assisted and context-guided electronic data capture on the FDA-approved mint Lesion TM software platform to enable cloud-based data collection and real-time analysis. The acquisition and annotation include radiological findings and radiomics performed directly on primary imaging data together with information from the patient history and clinical data. As proof of concept, anonymized data of 283 patients with either suspected or confirmed SARS-CoV-2 infection from eight European medical centers were aggregated in data analysis dashboards. Aggregated data were compared to key findings of landmark research literature. This concept has been chosen for use in the national COVID-19 response of the radiological departments of all university hospitals in Germany.

Background: In face of the Coronavirus Disease (COVID)-19 pandemic, best practice for mechanical ventilation in COVID-19 associated Acute Respiratory Distress Syndrome (ARDS) is intensely debated. Specifically, the rationale for high positive end-expiratory pressure (PEEP) and prone positioning in early COVID-19 ARDS has been questioned., Methods: The first 23 consecutive patients with COVID-19 associated respiratory failure transferred to a single ICU were assessed. Eight were excluded: five were not invasively ventilated and three received veno-venous ECMO support. The remaining 15 were assessed over the first 15 days of mechanical ventilation. Best PEEP was defined by maximal oxygenation and was determined by structured decremental PEEP trials comprising the monitoring of oxygenation, airway pressures and trans-pulmonary pressures. In nine patients the impact of prone positioning on oxygenation was investigated. Additionally, the effects of high PEEP and prone positioning on pulmonary opacities in serial chest x-rays were determined by applying a semiquantitative scoring-system. This investigation is part of the prospective observational PA-COVID-19 study., Findings: Patients responded to initiation of invasive high PEEP ventilation with markedly improved oxygenation, which was accompanied by reduced pulmonary opacities within 6 h of mechanical ventilation. Decremental PEEP trials confirmed the need for high PEEP (17.9 (SD ± 3.9) mbar) for optimal oxygenation, while driving pressures remained low. Prone positioning substantially increased oxygenation ( p <0.01)., Interpretation: In early COVID-19 ARDS, substantial PEEP values were required for optimizing oxygenation. Pulmonary opacities resolved during mechanical ventilation with high PEEP suggesting recruitment of lung volume., Funding: German Research Foundation, German Federal Ministry of Education and Research., Competing Interests: MD is European Society of Radiology (ESR) Research Chair (2019–2022) and the opinions expressed in this publication are the author's own and do not represent the view of ESR. MD gives lectures for Canon, and Guerbet, and holds hands-on cardiac CT courses (www.ct-kurs.de). He is Editor of Cardiac CT (Springer Nature). He has institutional research agreements with Siemens, General Electric, Philips, Canon, and has a patent on fractal analysis of perfusion imaging (jointly with Florian Michallek, PCT/EP2016/071551). All other authors declare no conflict of interest., (© 2020 The Author(s).)

Purpose: The aim of this retrospective study was to evaluate correlations between parameters of quantitative computed tomography (QCT) analysis, especially the 15th percentile of lung attenuation (P15), and parameters of clinical tests in a large group of patients with pulmonary emphysema., Patients and Methods: One hundred and seventy-two patients with pulmonary emphysema and chronic obstructive pulmonary disease (COPD) global initiative for chronic obstructive lung disease (GOLD) stage 3 or 4 were assessed by nonenhanced thin-section CT scans in full inspiratory and expiratory breath-hold, pulmonary function test (PFT), a 6-minute walk test (6MWT), and quality of life questionnaires (SGRQ and CAT). QCT parameters included total lung volume (TLV), total emphysema score (TES), and P15, all measured at inspiration (IN) and expiration (EX). Differences between inspiration and expiration were calculated for TLV (TLV Diff ), TES (TES Diff ), and P15 (P15 Diff ). Spearman correlation analysis was performed., Results: CT-measured lung volume in inspiration (TLV IN ) correlated strongly with spirometry-measured total lung capacity (TLC) (r=0.81, p <0.001) and moderately to strongly with residual volume (RV), forced vital capacity (FVC), and forced expiratory volume in 1 second (FEV 1 )/FVC (r=0.60, 0.56, and -0.49, each p <0.001). Lung volume in expiration (TLV EX ) correlated moderately to strongly with TLC, RV and FEV 1 /FVC ratio (r=0.75, 0.66, and -0.43, each p <0.001). TES and P15 showed stronger correlations with the carbon monoxide transfer coefficient (KCO%) (r= -0.42, 0.44, both p <0.001), when measured during expiration. P15 Diff correlated moderately with KCO% and carbon monoxide diffusing capacity (DLCO%) (r= 0.41, 0.40, both p <0.001). The 6MWT and most QCT parameters showed significant differences between COPD GOLD 3 and 4 groups., Conclusion: Our results suggest that QCT can help predict the severity of lung function decrease in patients with pulmonary emphysema and COPD GOLD 3 or 4. Some QCT parameters, including P15 EX and P15 Diff , correlated moderately to strongly with parameters of pulmonary function tests., Competing Interests: Author Bianca C Lassen-Schmidt is an employee of Fraunhofer MEVIS, the developer of the MeVis PULMO3D software. Ralf H Hubner reports personal fees from Pulmonx during the conduct of the study. All other authors report no conflicts of interest in this work., (© 2020 Song et al.)

Purpose: To evaluate the utility of attenuation correction (AC) of V/P SPECT images for patients with pulmonary emphysema., Materials and Methods: Twenty-one patients (mean age 67.6 years) with pulmonary emphysema who underwent V/P SPECT/CT were included. AC/non-AC V/P SPECT images were compared visually and semiquantitatively. Visual comparison of AC/non-AC images was based on a 5-point likert scale. Semiquantitative comparison assessed absolute counts per lung (aCpLu) and lung lobe (aCpLo) for AC/non-AC images using software-based analysis; percentage counts (PC = (aCpLo/aCpLu) × 100) were calculated. Correlation between AC/non-AC V/P SPECT images was analyzed using Spearman's rho correlation coefficient; differences were tested for significance with the Wilcoxon rank sum test., Results: Visual analysis revealed high conformity for AC and non-AC V/P SPECT images. Semiquantitative analysis of PC in AC/non-AC images had an excellent correlation and showed no significant differences in perfusion (ρ = 0.986) or ventilation (ρ = 0.979, p = 0.809) SPECT/CT images., Conclusion: AC of V/P SPECT images for lung lobe-based function imaging in patients with pulmonary emphysema do not improve visual or semiquantitative image analysis.

Objective: Endoscopic lung volume reduction (ELVR) with valves has been shown to improve COPD patients with severe emphysema. However, a major complication is pneumothoraces, occurring typically soon after valve implantation, with severe consequences if not managed promptly. Based on the knowledge that strain activity is related to a higher risk of pneumothoraces, we asked whether modifying post-operative medical care with the inclusion of strict short-term limitation of strain activity is associated with a lower incidence of pneumothorax., Methods: Seventy-two (72) emphysematous patients without collateral ventilation were treated with bronchial valves and included in the study. Thirty-two (32) patients received standard post-implantation medical management (Standard Medical Care (SMC)), and 40 patients received a modified medical care that included an additional bed rest for 48 hours and cough suppression, as needed (Modified Medical Care (MMC))., Results: The baseline characteristics were similar for the two groups, except there were more males in the SMC cohort. Overall, ten pneumothoraces occurred up to four days after ELVR, eight pneumothoraces in the SMC, and only two in the MMC cohorts (p=0.02). Complicated pneumothoraces and pneumothoraces after upper lobe treatment were significantly lower in MMC (p=0.02). Major clinical outcomes showed no significant differences between the two cohorts., Conclusions: In conclusion, modifying post-operative medical care to include bed rest for 48 hours after ELVR and cough suppression, if needed, might reduce the incidence of pneumothoraces. Prospective randomized studies with larger numbers of well-matched patients are needed to confirm the data.