Lung Volume Reduction Research Articles

Respiratory Function Tolerance of Rats with Vaying Degrees of Thoracic Volume Reduction.

To compare the effects of respiratory function on different degrees of reduced thoracic volume and evaluate the tolerance of rats with reduced thoracic volume, and to assess the feasibility of thoracic volume as a measure of the severity of rib fractures. A total of 24 10-week-old female Sprague-Dawley (SD) rats were randomly divided into four groups (n=6 in each group) according to the displacement degree of bilateral rib fractures (2, 4, 6, and 8 mm). The respiratory function of the rats（Tidal volume, Inspiration time, Expiration time, Breath rate, Minute volume, Peak inspiration flow) measured via whole-body barometric plethysmography before and after operation for 14 consecutive days. Respiratory function parameters of each group were analyzed. Chest CT scans were performed before and 14 days after operation, after that we reconstructed three-dimensional of the thoracic and lung and measured their volumes by computer software. We calculated the percentage of thoracic and lung volume reduction after operation. At the 14th day after the operation, the decline of thoracic volume rates of in the 2, 4, 6, and 8 mm groups were 5.20%, 9.01%, 16.67%, and 20.74%, respectively. The 8 mm group showed a significant reduction in lung volume. The postoperative tidal volumes were lower in each of the groups than the baseline values before the operation. The tidal volume of the 2 mm group gradually recovered after the operation and returned to a normal level (1.54 ± 0.07 mL) at 14th day after the operation. The tidal volume of the 4, 6, and 8 mm groups recovered gradually after the operation, but did not return to baseline level at the 14th day. In particular, the tidal volume of the 8 mm group was significantly lower than that of the other groups during the 14 days (1.23 ± 0.12 mL, p < 0.05). There were no significant changes in the inspiratory and expiratory times, peak inspiratory and expiratory flows, respiratory rate, and minute ventilation during the 14 days after the operation in each group. Displaced rib fractures lead to thoracic collapse and reduced thoracic volume, which can affect tidal volume in rats. The greater the decrease of thoracic volume, the more obvious the decrease of early tidal volume. The thoracic volume can be used as an objective parameter to evaluate the severity of multiple rib fractures. Early operation to restore thoracic volume may improve early respiratory function. Decreased thoracic volume affected respiratory function and can be compensated and recovered in the long term.

Caring for patients with advanced COPD: beyond the inhalers….

To understand the multidisciplinary approach to management of patients with advanced COPD.To recognise the parallel approaches to oxygen, NIV and dyspnoea management with consideration of more interventional options with lung volume reduction therapy or lung transplantation.To understand the high level of symptomatology present in advanced COPD and the relevance of palliative care alongside optimal medical management.

Improved exercise capacity results in a survival benefit after endobronchial valve treatment

BackgroundBronchoscopic lung volume reduction using endobronchial valves (EBV) is a treatment option for selected patients with advanced emphysema. The treatment significantly improves pulmonary function, exercise capacity, quality of life, and potentially improves survival. Our main aim was to assess whether treatment response significantly influences survival time after EBV treatment. MethodsWe evaluated treatment response at 6-week and 1-year follow-up of all patients treated with EBVs between 2008 and 2020. Survival status was retrieved on December 1, 2021. Patients were defined as responders or non-responders based on known minimal important differences for FEV1, residual volume (RV), RV/Total Lung Capacity (TLC) ratio, 6-min walk distance (6MWD), St. George's Respiratory Questionnaire (SGRQ), target lobe volume reduction (TLVR), and complete lobar atelectasis. Uni- and multivariate cox regression models were used to evaluate the effect of response on survival time. ResultsA total of 428 patients were included. EBV treatment resulted in significant improvements in pulmonary function, exercise capacity and quality of life. Median survival was 8.2 years after treatment. SGRQ and 6MWD response were independent predictors for improved survival time (Hazard Ratio (HR) 0.50 [0.28–0.89], p = .02 and HR 0.54 [0.30–0.94], p = .03, respectively). The presence of a complete lobar atelectasis did not significantly affect survival, neither did pulmonary function improvements. ConclusionsOur results suggest that improvement in exercise capacity and quality of life after EBV treatment are associated with a survival benefit, independent of improvements in pulmonary function, reduction in target lobe volume or the presence of complete lobar atelectasis.

Lung volume reduction surgery versus endobronchial valves: a randomised controlled trial.

Lung volume reduction surgery (LVRS) and bronchoscopic lung volume reduction (BLVR) with endobronchial valves can improve outcomes in appropriately selected patients with emphysema. However, no direct comparison data exist to inform clinical decision making in people who appear suitable for both procedures. Our aim was to investigate whether LVRS produces superior health outcomes when compared with BLVR at 12 months. This multicentre, single-blind, parallel-group trial randomised patients from five UK hospitals, who were suitable for a targeted lung volume reduction procedure, to either LVRS or BLVR and compared outcomes at 1 year using the i-BODE score. This composite disease severity measure includes body mass index, airflow obstruction, dyspnoea and exercise capacity (incremental shuttle walk test). The researchers responsible for collecting outcomes were masked to treatment allocation. All outcomes were assessed in the intention-to-treat population. 88 participants (48% female, mean±sd age 64.6±7.7 years, forced expiratory volume in 1 s percent predicted 31.0±7.9%) were recruited at five specialist centres across the UK and randomised to either LVRS (n=41) or BLVR (n=47). At 12 months follow-up, the complete i-BODE was available in 49 participants (21 LVRS/28 BLVR). Neither improvement in the i-BODE score (LVRS -1.10±1.44 versus BLVR -0.82±1.61; p=0.54) nor in its individual components differed between groups. Both treatments produced similar improvements in gas trapping (residual volume percent predicted: LVRS -36.1% (95% CI -54.6- -10%) versus BLVR -30.1% (95% CI -53.7- -9%); p=0.81). There was one death in each treatment arm. Our findings do not support the hypothesis that LVRS is a substantially superior treatment to BLVR in individuals who are suitable for both treatments.

Effects of an incentive spirometer versus a threshold inspiratory muscle trainer on lung functions in Parkinson’s disease patients: a randomized trial

Upper airway obstruction, reduced maximal expiratory and inspiratory flows, reduced lung volumes, abnormal ventilatory control, and diaphragmatic dyskinesias are reported in patients with Parkinson’s disease (PD). Inspiratory muscle training (IMT) has been reported to be effective in improving respiratory functions; however, no studies have compared the effects of the incentive spirometer (IS) with the threshold inspiratory muscle trainer (TIMT) in patients with PD. The study aimed to compare the effects of IS and TIMT on maximum inspiratory pressure (MIP), 6-min walk distance (6-MWD), forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), and peak expiratory flow rate (PEFR) in patients with stage 1–3 according to the Hoehn and Yahr scale. 18 patients were randomly assigned to two groups, i.e., incentive spirometer (IS) and threshold inspiratory muscle trainer (TIMT) group. The IS group received IMT with volume-based IS, and the TIMT group received IMT with TIMT. MIP, 6-MWD, FVC, FEV1, and PEFR were measured before and after six weeks of training. In IS group: A significant increase (p < 0.05) was observed in MIP and 6-MWD by 18.13 and 5%, respectively. In the TIMT group: A significant increase (p < 0.05) was observed in MIP and 6-MWD by 30.15 and 8.94%, respectively. Both groups observed no significant difference (p > 0.05) in FVC, FEV1, and PEFR. When the two groups were compared, a greater increase (p < 0.05) was observed in the MIP and 6-MWD in the TIMT group compared to IS group. IMT with IS or TIMT for six weeks effectively increased MIP and 6-MWD in patients with stage 1–3 (Hoehn and Yahr scale) of PD. No improvement was observed in FVC, FEV1, or PEFR with any of the techniques. TIMT is more effective than IS in improving MIP and 6-MWD.

Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease is a widely prevalent condition usually associated with cigarette consumption. It has a worldwide impact on the allocation of healthcare resources. The diagnosis is made by history and physical examination supported by measures of airflow and lung volume. The levels of impairment, disability and handicap dictate the requirements for medical care. Smoking cessation, immunization, maximal pharmacologic therapy including the use of supplemental oxygen and prompt attention to exacerbations, represent the basic principles of management. Pulmonary rehabilitation has been shown in a number of randomized clinical trials to improve functional exercise capacity and health-related quality of life. Many interesting approaches, such as lung volume reduction, lung transplantation, nutritional support and mechanical ventilation for acute exacerbations, are in various stages of clinical use and evaluation.

Lung volume reduction surgery for ipsilateral emphysematous bullae after congenital diaphragmatic hernia repair

Lung volume reduction surgery for ipsilateral emphysematous bullae after congenital diaphragmatic hernia repair

Life-threatening pulmonary laceration following bronchoscopic lung volume reduction

Life-threatening pulmonary laceration following bronchoscopic lung volume reduction

Positive Expiratory Pressure Therapy Device, the Acapella in Post-ECMO Rehabilitation

Depending on the choice of cannulation techniques, ECMO can deliver purely respiratory support, respiratory support with right ventricular support, and full cardiopulmonary support. Today, with careful patient selection, ECMO is used as a rescue therapy to allow for recovery or bridge to transplant for hypoxic respiratory failure and severe refractory cardiogenic shock. The adverse effects of deep sedation and paralysis including bradycardia, ICU-acquired paresis, and ventilator-associated pneumonia pose valid concerns with reduction in lung volumes and capacities. One of the most frequently prescribed airway clearance therapy (ACT) options for patients with chronic lung conditions or decreased lung volumes is positive expiratory pressure therapy (PEP) device (Acapella) which causes reduction in hyperinflation and many other positive facts described in this review.

COVID and Cancer: A Complete 3D Advanced Radiological CT-Based Analysis to Predict the Outcome.

Cancer patients infected with COVID-19 were shown in a multitude of studies to have poor outcomes on the basis of older age and weak immune systems from cancer as well as chemotherapy. In this study, the CT examinations of 22 confirmed COVID-19 cancer patients were analyzed. A retrospective analysis was conducted on 28 cancer patients, of which 22 patients were COVID positive. The CT scan changes before and after treatment and the extent of structural damage to the lungs after COVID-19 infection was analyzed. Structural damage to a lung was indicated by a change in density measured in Hounsfield units (HUs) and by lung volume reduction. A 3D radiometric analysis was also performed and lung and lesion histograms were compared. A total of 22 cancer patients were diagnosed with COVID-19 infection. A repeat CT scan were performed in 15 patients after they recovered from infection. Most of the study patients were diagnosed with leukemia. A secondary clinical analysis was performed to show the associations of COVID treatment on the study subjects, lab data, and outcome on mortality. It was found that post COVID there was a decrease of >50% in lung volume and a higher density in the form of HUs due to scar tissue formation post infection. It was concluded that COVID-19 infection may have further detrimental effects on the lungs of cancer patients, thereby, decreasing their lung volume and increasing their lung density due to scar formation.

Застосування відеоасистованих операцій зі зменшення об’єму легені при бульозній емфіземі легень в клінічній практиці

Abstract. Bullous emphysema of the lungs (BEL) is a chronic pulmonary disease, induced by the weakening of the alveoli walls in the lungs, resulting in abnormally large air spaces (bullae), which are filled with air, even when the patient exhales. Object and research methods. The practical experience of performing video-assisted (VATS) lung volume reduction (LVR) operations in 2 cases with BEL is given. Results and their discussion. After performing the LVR patients had improved breathing, reduced manifestations of respiratory failure and angina pectoris, increased blood gas parameters: an increase in SpO2 from 86 % to 96 %, a decrease in PaCO2 from 47 mmHg up to 40 mmHg. Conclusions. LVR is an effective method of treatment of BEL, in the presence of isolated bulls, this operation causes a significant reduction in respiratory failure, especially in patients with bronchial asthma and coronary artery disease.

Cabin Pressure Altitude Effect on Acceleration Atelectasis After Agile Flight Breathing 60% Oxygen.

INTRODUCTION: A flight trial was conducted to determine whether breathing 60% oxygen during high performance flight maneuvers using contemporary pilot flight equipment induces atelectasis and to explore whether cabin altitude had any influence on the extent of atelectasis identified.METHODS: On 2 separate days, 14 male aircrew flew as passengers at High [14,500-18,000 ft (4420-5486 m)] and Low [4000-6000 ft (1219-1829 m)] cabin pressure altitude in a Hawk T Mk1 aircraft breathing 60% oxygen. Sorties comprised 16 maneuvers at +5 Gz, each sustained for 30 s. Lung volumes (spirometry), basal lung volume (electrical impedance tomography, EIT), and peripheral oxygen saturation during transition from hyperoxia to hypoxia (pulmonary shunt fraction) were measured in the cockpit immediately before (Pre) and after (Post) flight.RESULTS: Forced inspiratory vital capacity (FIVC) was significantly lower Postflight after High (-0.24 L) and Low (-0.38 L) sorties, but recovered to Preflight values by the fourth repeat (FIVC4). EIT-derived measures of FIVC decreased after High (-3.3%) and Low (-4.4%) sorties but did not recover to baseline by FIVC4. FIVC reductions were attributable to decreased inspiratory capacity. Spo₂ was lower Postflight than Preflight in High and Low sorties.DISCUSSION: Breathing 60% oxygen during flight results in a 3.8-4.9% reduction in lung volume associated with a small decrease in blood oxygenation and an estimated pulmonary shunt of up to 5.7%. EIT measures suggest persisting airway closure despite repeated FIVC maneuvers. There was no meaningful influence of cabin pressure altitude. The operational consequence of the observed changes is likely to be small.Tank H, Kennedy G, Pollock R, Hodkinson P, Sheppard-Hickey R-A, Woolford J, Green NDC, Stevenson A. Cabin pressure altitude effect on acceleration atelectasis after agile flight breathing 60% oxygen. Aerosp Med Hum Perform. 2023; 94(1):3-10.

A Comparative Study of Oxygen Saturation (Spo2) At Rest and after 6-Minutes Walking Test in Young Adults with Variable BMI

Background: Exercise affects every system of the body and cause several changes in them and respiratory changesare most important. Changes in blood levels of oxygen are very vital during exercise. The respiratory system ismost efficient in young adults and undergoes various anatomical, physiological and immunological changes withage and hence blood levels of oxygen during exercise is more affected in elderly as compared to young adults..But increased body mass index affects respiratory system of even young adults so there blood levels of oxygen aremore compromised as compared to normal BMI young adults during exercise.Objective: Under normal circumstances in the blood there is a reserve of oxygen. However, when doing exercise,the body requires oxygen in large quantities to meet the need for energy. If the level of oxygen in the blooddecreases beyond the normal limit, it will be very dangerous for the body. Health risks are associated with obesity,including its effects on respiratory function. Respiratory muscle weakness in obesity has been linked to muscleweakness as a result of decreased compliance of the chest wall or reduced lung volume or can occur both.Aim: Is to study the effect exercise on SpO2 in young adults with variable BMI.Method: A comparative cross-sectional analytical study was conducted on 106 young adults in Medical Collegein North India. Data was collected by using self-administered questionnaire followed by anthropometricmeasurement. Body Mass Index (BMI) was calculated by Quetelet’s index. Oxygen saturation at rest and after6-minutes walking test was recorded by using pulse oximeter. Data analyzed on SPSS version 20.0 and variousstatistical tests were applied to find the correlation and significance.Results: The students with high BMI show negative correlation with oxygen saturation (SpO2) at rest and after 6-minutes walking test. This correlation is statistically significant. Conclusion: There is more decrease in oxygen saturation (SpO2) in students with high BMI after 6-minuteswalking test as compared to students with normal BMI. Weight management is recommended to young adults inorder to prevent early impact of increased BMI on respiratory system.

Efficiency and Reliability of Bronchoscopic Lung Volume Reduction Coil Application in Patients with Severe Emphysema.

In the past years, surgery has been used for the non-medical treatment of severe emphysema. However, in recent years, bronchoscopic lung volume reduction (LVR) treatment has become more preferred because it is less invasive. Bronchoscopic coil treatment is the most frequently applied technique among these methods. The aim of the investigation was to determine the efficacy and safety of bronchoscopic volume reduction coil treatment for patients with severe emphysema. The patients who were performed bronchial volume reduction coil treatment between 2015 and 2017 and were followed in our outpatient clinic were retrospectively examined. They were followed for 1 year at quarterly intervals after the procedure. All the safety and efficacy of the patient's records, including the modified Medical Research Council (MRC) dyspnea score, the St. George's Respiratory Questionnaire (SGRQ) quality of life scale, the 6 min walk distance (6-MWT), pulmonary function tests, and adverse events, were evaluated. Sixteen patients were included in the study. The mean of the preoperative mMRC clinic dyspnea score was 3.38, the mean of the 3rd month's mMRC score was 2.62 (p=0.007), and the mean of the 12th month's mMRC was 2.37 (p=0.003). The preoperative SGRQ quality of life parameter was 71.95±15.7, the 3rd month was 66.7±16.2 (p=0.007), and the 12th month was 62.9±16.4 (p=0.003). Preoperative mean of 6-MWT was 247.25±112.36 m, 3rd month 264.25±95 m (p=0.148), and 12th month 317±122.9 m (p=0.034). Patients' preoperative residual volume was 5.28±1.96 L, 3rd month 4.52±1.35 L (p=0.023), and 12th month 4.545±1.83 L (p=0.163). Patients' preoperative forced expiratory volume in one second, respectively, was 0.79±0.29 L, 3rd month 0.79±0.3 L (p=0.917), and 12th month 0.86±0.3 L (p=0.756). It seems that bronchoscopic LVR coil treatment, which is an effective and reliable procedure that reduces shortness of breath rather than respiratory function test parameters and improves the quality of daily life, will become even more widespread.

Impact of Coronavirus Disease 2019 on Hospital Admissions, Health Status, and Behavioral Changes of Patients with COPD.

Patients with chronic obstructive pulmonary disease (COPD) have an increased risk of acquiring severe coronavirus disease 2019 (COVID-19), which is why self-isolation was recommended. However, long periods of social isolation, accompanied by limited access to health care systems, might influence the outcome of patients with severe COPD negatively. Data from COPD and pneumonia patients at Charité-Universitätsmedizin Berlin and the volume of endoscopic lung volume reduction (ELVR) surgeries from the German Lung Emphysema Registry (Lungenemphysem Register e.V.) were analyzed from pre-pandemic (2012 to 2019) to the pandemic period (2020 and 2021). In addition, 52 patients with COPD Global initiative for chronic Obstructive Lung Disease (GOLD) stage 4 status included in the lung emphysema registry received questionnaires during lockdowns from June 2020 to April 2021. Admissions and ventilation therapies administered to COPD patients significantly decreased during the COVID-19 pandemic. Likewise, there was a reduction in ELVR treatments and follow-ups registered in German emphysema centers. Mortality was slightly higher among patients hospitalized with COPD during the pandemic. Increasing proportions of COPD patients with GOLD stage 3 and GOLD stage 4 status reported behavioral changes and subjective feelings of increasing COPD symptoms the longer the lockdown lasted. However, COPD symptom questionnaires revealed stable COPD symptoms over the pandemic time period. This study reveals reduced COPD admissions and elective treatment procedures of COPD patients during the pandemic, but a slight increase in mortality among patients hospitalized with COPD, irrespective of COVID-19. Correspondingly, patients with severe COPD reported subjective deterioration of their health status, probably caused by their very strict compliance with lockdown measures.

The effect of bronchoscopic lung volume reduction on the bronchodilator response

The effect of bronchoscopic lung volume reduction on the bronchodilator response

A Model to Predict Residual Volume from Forced Spirometry Measurements in Chronic Obstructive Pulmonary Disease.

Lung hyperinflation with elevated residual volume (RV) is associated with poor prognosis in adults with chronic obstructive pulmonary disease (COPD) and is a critical criterion for lung volume reduction selection. Here, we proposed that patterns within spirometric measures could represent the degree of hyperinflation. Fractional polynomial multivariate regression was used to develop a prediction model based on age, biological sex, forced expiratory volume in 1 second (FEV1), and forced vital capacity (FVC) to estimate plethysmography measured RV in patients in the Pittsburgh Specialized Center for Clinically Oriented Research (SCCOR) cohort (n=450). Receiver operating characteristic area under the curve (ROC-AUC) and optimal cut-points from the model were identified. The model was validated in a separate cohort (n=793). The best fit model: RV %est=[FVC %predicted] x 3.46-[FEV1/FVC] x 179.80- [FVC % (sqrt)] x 79.53-[age] x 0.98- [sex] x 10.88 + 737.06, where [sex], m=1. R2 of observed versus %predicted RV was 0.71. The optimal cut-point to predict an RV % >175% was 161. At this cut-point, ROC-AUC was 0.95, with a sensitivity 0.95, specificity 0.86, positive predictive value (PPV) of 97%, negative predictive value (NPV) of 76%, positive likelihood ratio (LR) of 6.6, and negative LR of 0.06. In a validation cohort of COPD patients (n=793), the model performed similarly, with a sensitivity of 0.82, specificity of 0.83, PPV of 85%, NPV of 79%, positive LR of 4.7, and negative LR of 0.21. In patients with COPD, a model using only spirometry, age, and biological sex can estimate elevated RV. This tool could facilitate the identification of candidates for lung volume reduction procedures and can be integrated into existing epidemiologic databases to investigate the clinical impact of hyperinflation.

Associating Serum IgM, IgA Levels with Thoracic CT Indicators and Pulmonary Function Indexes in Acutely Exacerbated Chronic Obstructive Pulmonary Disease Patients.

Chronic Obstructive Pulmonary Disease (COPD) is a respiratory condition characterized by acute exacerbations and reduced lung function. This study investigates the link between serum markers (Immunoglobulin M (IgM) and Immunoglobulin A (IgA)), thoracic computed tomography (CT) scan findings, and pulmonary function indexes during these episodes, aiming to improve our understanding and identify new diagnostic indicators. From the First Affiliated Hospital of Hebei North University, we selected 89 COPD patients experiencing acute exacerbation within the past two years for our Acute Exacerbation Group (AG). Meanwhile, 96 COPD patients, initially treated at the same hospital and currently deemed stable, were chosen for the Stable Group (SG). Both groups underwent serum IgM and IgA tests, thoracic CT examinations, and pulmonary function assessments. In the AG Group, the serum IgM levels were marginally lower than in the Stable Group (SG), though the difference wasn't statistically significant (p = 0.097). Conversely, serum IgA levels in the AG were significantly lower than in the SG (p < 0.001). The AG also showed markedly reduced lung volume, inspiratory lung density, and pulmonary function indexes compared to the SG while having considerably higher values for emphysema index (EI) and air trapping index (ATI) (all p < 0.001). Pearson correlation analysis revealed that lung volume, average inspiratory lung density, and IgA levels had strong positive correlations with one-second forced expiratory volume (FEV1), FEV1/forced vital capacity (FVC), and diffuse carbon monoxide (DLCO) (with respective r-values of 0.824, 0.841, and 0.829; all p < 0.001). In contrast, EI and ATI exhibited significantly negative correlations with FEV1, FEV1/FVC, and DLCO (with r-values ranging from -0.837 to -0.885; all p < 0.001). The assessment of serum IgA combined with thoracic CT parameters offers valuable insights for diagnosing and evaluating acute exacerbations of COPD, presenting a straightforward clinical utility.

Bronchoscopic Lung Volume Reduction in Patients with Emphysema due to Alpha-1 Antitrypsin Deficiency

Background: Bronchoscopic lung volume reduction using one-way endobronchial valves (EBVs) is a valid therapy for severe emphysema patients. However, alpha-1 antitrypsin (AAT)-deficient patients were excluded from the majority of clinical trials investigating this intervention. Objectives: The aim of this study was to investigate the feasibility, efficacy, and safety of EBV treatment in patients with AAT deficiency (AATD) or a reduced AAT level. Method: A retrospective analysis was performed of all patients treated with EBV with confirmed AATD or with a reduced AAT serum level at the University Medical Center Groningen between 2013 and 2021. Baseline and 6-month follow-up assessment included chest CT, pulmonary function measurement, 6-min walking distance (6MWD), and St. George’s Respiratory Questionnaire (SGRQ). Results: In total, 53 patients were included, 30 patients in the AATD group (AAT <0.6 g/L or confirmed ZZ phenotype) and 23 patients in the reduced AAT group (AAT 0.6–1 g/L). In both groups, all response variables improved significantly after treatment. There was a median increase in forced expiratory volume in 1 s of 105 mL (12% relative) and 280 mL (31% relative) in the AATD and reduced AAT groups, respectively. 6MWD increased by 62 min and 52 min, and SGRQ decreased by 12.5 patients and 18.7 patients, respectively. A pneumothorax occurred in 10% and 13% of patients, and no patients died. Conclusions: EBV treatment in patients with emphysema and AATD or a reduced AAT level is feasible and results in significant improvements in pulmonary function, exercise capacity, and quality of life and has an acceptable safety profile.

Effect of Chest Computed Tomography Kernel Use on Emphysema Score in Severe Chronic Obstructive Pulmonary Disease Patients Evaluated for Lung Volume Reduction

Background: Chest computed tomography (CT) emphysema quantification is a vital diagnostic tool in patient evaluation for bronchoscopic lung volume reduction (BLVR). Smooth kernels for CT image reconstruction are generally recommended for quantitative analyses. This recommendation is not always followed, which may affect quantification of emphysema extent and eventually, treatment decisions. Objective: The main goal is to demonstrate the influence of CT reconstruction kernels on emphysema quantification in patients with severe COPD, considered for BLVR. Methods: Chest CT scans were acquired with one multi-detector CT system and reconstructed using three different kernels: smooth, medium smooth, and sharp. Other parameters were kept constant. Emphysema scores (ESs), meaning the percentage of voxels below −950 Hounsfield units, were calculated and compared to the smooth reference kernel using paired t tests. Bland-Altman plots were made to assess the biases and limits of agreement between kernels. Results: Ninety-eight COPD patient CT scans were analyzed. The sharp kernel had a systematic bias of 6.2% and limits of agreement of 16.6% to −4.2% compared to the smooth kernel. The medium smooth kernel had a systematic bias of 5.7% and limits of agreement of 9.2% and 2.2% compared to the smooth kernel. The ES differed, for a single patient, up to 18% for different kernels. Conclusions: Chest CT kernel reconstruction can lead to a significant difference in emphysema severity quantification. This may cause invalid treatment selection in COPD patients evaluated for BLVR. Standardization of a smooth CT kernel setting and/or normalization to a standard kernel is strongly recommended.