Lung Volume Reduction Surgery

Autobullectomy with COVID-19 in a patient with chronic obstructive pulmonary disease

A 72-year-old man with chronic obstructive pulmonary disease (COPD) was admitted for coronavirus disease 2019 (COVID-19). He was discharged on day 30; however, he was readmitted 6 days later due to a left lung organizing pneumonia secondary to COVID-19. After methylprednisolone treatment, the patient was discharged on day 15. One year later, computed tomography showed shrinkage of emphysematous lesions, and both total lung capacity measured using computed tomography and fraction of low attenuation volume decreased in the left lung compared to that before COVID-19. Here, we report a rare case of autobullectomy with COVID-19 in a patient with COPD.

Alpha1-antitrypsin Disease, Treatment and Role for Lung Volume Reduction Surgery

Chronic obstructive pulmonary usually is subcategorized into 2 groups: chronic bronchitis and emphysema. The main cause of chronic bronchitis and emphysema is smoking; however, alpha1-antitrypsin also has been seen to cause emphysema in patients who are deficient. As symptoms and lung function decline, treatment modalities, such as lung volume reduction surgery, have been used in individuals with chronic obstructive pulmonary disease and upper lobe predominant emphysema. This article analyzes multiple published series where lung volume reduction surgery has been used in individuals with alpha1-antitrypsin deficiency and their overall outcomes.

Emphysema and lung volume reduction: the role of radiology

Chronic obstructive pulmonary disease (COPD) is one of the leading causes of death worldwide. One of the main findings is pulmonary emphysema in association with chronic bronchitis. Clinical signs, pulmonary function tests and imaging are the current used methods to diagnose and stage emphysema. Lung volume reduction (LVR) and endoscopic lung volume reduction (ELVR) are the current therapeutic options beside lung transplantation in cases of severe emphysema. Nowadays imaging is one of the key factors for the success of these therapies. Especially quantitative computed tomography (CT) with its increasing possibilities has become a viable tool, providing detailed information about distribution and heterogeneity of emphysema. Other imaging techniques like dual-energy CT (DECT) and functional magnetic resonance (MR) have shown to add functional information. These structural and functional information support thoracic surgeons and interventional pulmonologists in selecting patients and optimizing LVR procedures but also enables the development of new endobronchial therapies. Imaging will further improve the individual outcome by supporting the choice of optimal therapy.

Improved prediction of lobar perfusion contribution using technetium-99m-labeled macroaggregate of albumin single photon emission computed tomography/computed tomography with attenuation correction

OBJECTIVE

Lung cancer resection can require removal of an entire lobe and, at times, bilobectomy or pneumonectomy. Many patients will also have significantly compromised lung function that requires limiting the extent of surgery or could preclude surgery altogether. The preoperative assessment should include predicted postoperative forced expiratory volume in 1 second (ppoFEV1), because a ppoFEV1 of <40% predicts significantly increased perioperative morbidity. The ppoFEV1 can be estimated by multiplying the preoperative FEV1 by the residual perfused territory percentage, as predicted on planar perfusion scintigraphy (PPS). However, ppoFEV1 using PPS has shown variable correlation with spirometry-measured postoperative FEV1.

METHODS

We propose an improved method for assessing regional lung perfusion in preoperative lung surgery patients. Patients undergo single photon emission computed tomography/computed tomography (SPECT/CT) imaging with attenuation correction using the conventional perfusion agent, technetium-99m-labeled macroaggregate of albumin. The CT image provides information for manual segmentation of each lobe. These segmentations are applied to the SPECT images to determine lobar perfusion. This proposed method was compared with PPS.

RESULTS

This technique was evaluated in 17 patients. As expected, the perfusion contributions of the right and left lungs, calculated from SPECT/CT, correlated closely with those obtained from PPS (Pearson r=0.995). However, the lobar perfusion contributions obtained by PPS and SPECT/CT were significantly different, by 2 methods of comparison (Hotelling's P=1.7×10(-6) and P=1.7×10(-4)).

CONCLUSIONS

This new SPECT/CT technique provides an anatomically more accurate assessment of lobar perfusion. This technique can refine which patients should be operative candidates and allow better prediction of postoperative function in contrast to the anatomically inaccurate planar scintigraphic predictions, which often underestimate the postoperative FEV1. This new technique is expected to have a significant effect on the resectability of patients with lung cancer.

Outcomes in lung transplantation after previous lung volume reduction surgery in a contemporary cohort

OBJECTIVES

Lung volume reduction surgery (LVRS) provides palliation and improved quality of life in select patients with end-stage chronic obstructive pulmonary disease (COPD). The effect of previous LVRS on lung transplant outcomes has been inadequately studied. We report our experience in the largest single institution series of these combined procedures.

METHODS

The records of 472 patients with COPD undergoing lung transplantation or LVRS between 1995 and 2010 were reviewed. Outcomes of patients undergoing transplant after LVRS were compared with outcomes of patients undergoing transplant or LVRS alone. Survival was compared using log-rank tests and the Kaplan-Meier method.

RESULTS

Demographics, comorbidities, and spirometry were similar at the time of transplantation. Patients who had undergone lung transplant after LVRS had longer transplant operative times (mean 4.4 vs 5.6 hours; P = .020) and greater hospital length of stay (mean 17.6 vs 29.1 days; P = .005). Thirty-day mortality and major morbidity were similar. Posttransplant survival was reduced for transplant after LVRS (median, 49 months; 95% confidence interval [CI], 16, 85 months) compared with transplant alone (median, 96 months; 95% CI, 82, 106 months; P = .008). The composite benefit of combined procedures, defined as bridge from LVRS to transplant of 55 months and posttransplant survival of 49 months (total 104 months), was comparable with survival of patients undergoing either procedure alone.

CONCLUSIONS

Lung transplant after LVRS leads to minimal additional perioperative risk. The reduced posttransplant survival in patients undergoing combined procedures is in contradistinction to reports from other smaller series. When determining the best surgical treatment for patients with more severe disease, the benefit of LVRS before transplant should be weighed against the consequence of reduced posttransplant survival.

Bronchoscopic interventions in the management of chronic obstructive pulmonary disease

PURPOSE OF REVIEW

In the past few years, there have been exciting developments in bronchoscopic efforts at attaining lung volume reduction (LVR), given real and perceived risks of surgical LVR. The purpose of this review is to discuss these techniques, with special emphasis on what we have learnt in the past 1-2 years.

RECENT FINDINGS

Bronchoscopic techniques can be broadly classified as one-way valves, which allow air to exit but not enter, thus reducing air trapping; airway bypass stents, which create an extra-anatomical pathway for air to exit; biologic and polymeric substances, which seal the emphysematous lung, eventually collapsing it; bronchial thermal vapor ablation, which causes thermal damage and thus achieves LVR; and endobronchial elastic coils, which mechanically cause LVR. The specific role of these is being defined by recent publications. The central role of collateral ventilation in choosing amongst these procedures is now established, as it has become clear that in the presence of collateral ventilation, valves provide only modest benefit, if any at all. Thus it is of interest that the other modalities which are independent of collateral ventilation are being studied further.

SUMMARY

Though the preliminary results are quite encouraging, further trials need to be done before these procedures can be adopted in daily practice.

Oxygen-enhanced MRI, thin-section MDCT, and perfusion SPECT/CT: comparison of clinical implications to patient care for lung volume reduction surgery

OBJECTIVE

The purpose of our study was to prospectively and directly compare capability of O2-enhanced MRI, MDCT, and perfusion SPECT/CT to clinical outcome measurements in candidates for lung volume reduction surgery (LVRS).

SUBJECTS AND METHODS

Twenty-five consecutive candidates for LVRS (20 men and five women; age range, 45-76 years) underwent MDCT, O2-enhanced MRI, and perfusion SPECT/CT before and after LVRS. Clinical outcomes for each candidate were evaluated in terms of differences between pre- and postoperative percentage forced expiratory volume in 1 second (%FEV1), Pao2, and 6-minute walking distance. Quantitatively assessed upper/lower lung ratios on O2-enhanced MRI, MDCT, and SPECT/CT were calculated from regional relative enhancement ratios, functional lung volumes, and radioisotope uptakes between upper and lower lungs. Qualitatively assessed upper/lower lung ratios on O2-enhanced MRI, MDCT, and SPECT/CT were estimated using visual scoring systems. To evaluate the correlation for individual upper/lower lung ratios and clinical outcomes, all upper/lower lung ratios were correlated with clinical outcomes. Improvements in mean relative enhancement ratio were directly correlated with clinical outcomes to assess the capability of O2-enhanced MRI to assess therapeutic effect.

RESULTS

All quantitatively (-0.63≤r≤-0.47, p<0.05) and qualitatively (0.41≤r≤0.57, p<0.05) assessed upper/lower lung ratios showed moderate and statistically significant correlation with clinical outcomes, and improvement in mean relative enhancement ratio showed moderate or good correlation, both statistically significant (-0.44≤r≤0.71, p<0.05).

CONCLUSION

O2-enhanced MRI shows potential for more accurate evaluation of postoperative clinical outcome for LVRS candidates than SPECT/CT and can be considered at least as reliable as MDCT.

Quality of life in pulmonary surgery: choosing, using, and developing assessment tools

There is mounting recognition that, to aid surgical decision making, treatment efficacy needs to be measured in a variety of ways, with health-related quality of life now widely regarded as an important outcome in pulmonary surgical populations. The aim of this review is to provide a comprehensive overview of the key issues to consider if an investigator wishes to incorporate health-related quality of life assessment into trials and studies of pulmonary surgery, drawing on recent studies of lung cancer surgery as an example.

An evidence-based estimate on the size of the potential patient pool for lung volume reduction surgery

BACKGROUND

Observational and randomized studies have demonstrated that lung volume reduction surgery (LVRS) improves symptoms, lung function, and survival in selected patients with emphysema. In spite of an approximately 3.8 million patient prevalence of the disease in the US, only 119 LVRS procedures were performed nationwide under Medicare during 2008. In order to obtain evidence-based estimate on the size of the patient pool potentially suitable for LVRS, we analyzed the database from our clinical practice that is representative of a substantial segment of the general emphysema population.

METHODS

Our pulmonary function test laboratory database between 1996 and 2006 was searched for patients with stage III and IV global initiative for chronic obstructive lung disease (GOLD) who also had lung volumes and carbon monoxide diffusing capacity data. Patients without available chest computed tomographic scans (CT) or with primary diagnoses other than emphysema were excluded. The resultant emphysema cohort was screened using clinical inclusion and exclusion criteria adopted from the National Emphysema Treatment Trial. A suitable clinical profile combined with CT scan evidence of 40% or greater involvement of the lungs and predominantly upper lobe distribution of emphysema were regarded as favorable markers for LVRS.

RESULTS

Pulmonary function test criteria were met by 959 patients and CT scans were available in 588 patients, but 175 patients were excluded because of primary diagnoses other than emphysema. In the remaining 413 patients, 61 or 15% exhibited favorable clinical profiles and anatomy for LVRS.

CONCLUSIONS

In a subset of patients that resembles a substantial segment of the general population with advanced emphysema, up to 15% appeared potential candidates for LVRS. Formation of a task force by relevant medical specialty and patient advocate organizations to address the apparent underutilization of LVRS is recommended.

Lung transplantation and lung volume reduction surgery

Since the publication of the last edition of the Handbook of Physiology, lung transplantation has become widely available, via specialized centers, for a variety of end-stage lung diseases. Lung volume reduction surgery, a procedure for emphysema first conceptualized in the 1950s, electrified the pulmonary medicine community when it was rediscovered in the 1990s. In parallel with their technical and clinical refinement, extensive investigation has explored the unique physiology of these procedures. In the case of lung transplantation, relevant issues include the discrepant mechanical function of the donor lungs and recipient thorax, the effects of surgical denervation, acute and chronic rejection, respiratory, chest wall, and limb muscle function, and response to exercise. For lung volume reduction surgery, there have been new insights into the counterintuitive observation that lung function in severe emphysema can be improved by resecting the most diseased portions of the lungs. For both procedures, insights from physiology have fed back to clinicians to refine patient selection and to scientists to design clinical trials. This section will first provide an overview of the clinical aspects of these procedures, including patient selection, surgical techniques, complications, and outcomes. It then reviews the extensive data on lung and muscle function following transplantation and its complications. Finally, it reviews the insights from the last 15 years on the mechanisms whereby removal of lung from an emphysema patient can improve the function of the lung left behind.

Mechanisms of gas exchange response to lung volume reduction surgery in severe emphysema

Lung volume reduction surgery (LVRS) improves lung function, respiratory symptoms, and exercise tolerance in selected patients with chronic obstructive pulmonary disease, who have heterogeneous emphysema. However, the reported effects of LVRS on gas exchange are variable, even when lung function is improved. To clarify how LVRS affects gas exchange in chronic obstructive pulmonary disease, 23 patients were studied before LVRS, 14 of whom were again studied afterwards. We performed measurements of lung mechanics, pulmonary hemodynamics, and ventilation-perfusion (Va/Q) inequality using the multiple inert-gas elimination technique. LVRS improved arterial Po₂ (Pa(O₂)) by a mean of 6 Torr (P = 0.04), with no significant effect on arterial Pco₂ (Pa(CO₂)), but with great variability in both. Lung mechanical properties improved considerably more than did gas exchange. Post-LVRS Pa(O₂) depended mostly on its pre-LVRS value, whereas improvement in Pa(O(2)) was explained mostly by improved Va/Q inequality, with lesser contributions from both increased ventilation and higher mixed venous Po(2). However, no index of lung mechanical properties correlated with Pa(O₂). Conversely, post-LVRS Pa(CO₂) bore no relationship to its pre-LVRS value, whereas changes in Pa(CO₂) were tightly related (r² = 0.96) to variables, reflecting decrease in static lung hyperinflation (intrinsic positive end-expiratory pressure and residual volume/total lung capacity) and increase in airflow potential (tidal volume and maximal inspiratory pressure), but not to Va/Q distribution changes. Individual gas exchange responses to LVRS vary greatly, but can be explained by changes in combinations of determining variables that are different for oxygen and carbon dioxide.

Lung volume reduction therapies for advanced emphysema: an update

Observational and randomized studies provide convincing evidence that lung volume reduction surgery (LVRS) improves symptoms, lung function, exercise tolerance, and life span in well-defined subsets of patients with emphysema. Yet, in the face of an estimated 3 million patients with emphysema in the United States, < 15 LVRS operations are performed monthly under the aegis of Medicare, in part because of misleading reporting in lay and medical publications suggesting that the operation is associated with prohibitive risks and offers minimal benefits. Thus, a treatment with proven potential for palliating and prolonging life may be underutilized. In an attempt to lower risks and cost, several bronchoscopic strategies (bronchoscopic emphysema treatment [BET]) to reduce lung volume have been introduced. The following three methods have been tested in some depth: (1) unidirectional valves that allow exit but bar entry of gas to collapse targeted hyperinflated portions of the lung and reduce overall volume; (2) biologic lung volume reduction (BioLVR) that involves intrabronchial administration of a biocompatible complex to collapse, inflame, scar, and shrink the targeted emphysematous lung; and (3) airway bypass tract (ABT) or creation of stented nonanatomic pathways between hyperinflated pulmonary parenchyma and bronchial tree to decompress and reduce the volume of oversized lung. The results of pilot and randomized pivotal clinical trials suggest that the bronchoscopic strategies are associated with lower mortality and morbidity but are also less efficient than LVRS. Most bronchoscopic approaches improve quality-of-life measures without supportive physiologic or exercise tolerance benefits. Although there is promise of limited therapeutic influence, the available information is not sufficient to recommend use of bronchoscopic strategies for treating emphysema.

Perfusion scintigraphy and patient selection for lung volume reduction surgery

RATIONALE

It is unclear if lung perfusion can predict response to lung volume reduction surgery (LVRS).

OBJECTIVES

To study the role of perfusion scintigraphy in patient selection for LVRS.

METHODS

We performed an intention-to-treat analysis of 1,045 of 1,218 patients enrolled in the National Emphysema Treatment Trial who were non-high risk for LVRS and had complete perfusion scintigraphy results at baseline. The median follow-up was 6.0 years. Patients were classified as having upper or non-upper lobe-predominant emphysema on visual examination of the chest computed tomography and high or low exercise capacity on cardiopulmonary exercise testing at baseline. Low upper zone perfusion was defined as less than 20% of total lung perfusion distributed to the upper third of both lungs as measured on perfusion scintigraphy.

MEASUREMENTS AND MAIN RESULTS

Among 284 of 1,045 patients with upper lobe-predominant emphysema and low exercise capacity at baseline, the 202 with low upper zone perfusion had lower mortality with LVRS versus medical management (risk ratio [RR], 0.56; P = 0.008) unlike the remaining 82 with high perfusion where mortality was unchanged (RR, 0.97; P = 0.62). Similarly, among 404 of 1,045 patients with upper lobe-predominant emphysema and high exercise capacity, the 278 with low upper zone perfusion had lower mortality with LVRS (RR, 0.70; P = 0.02) unlike the remaining 126 with high perfusion (RR, 1.05; P = 1.00). Among the 357 patients with non-upper lobe-predominant emphysema (75 with low and 282 with high exercise capacity) there was no improvement in survival with LVRS and measurement of upper zone perfusion did not contribute new prognostic information.

CONCLUSIONS

Compared with optimal medical management, LVRS reduces mortality in patients with upper lobe-predominant emphysema when there is low rather than high perfusion to the upper lung.

Pharmacogenetics of chronic obstructive pulmonary disease: challenges and opportunities

Similar to other common chronic diseases, chronic obstructive pulmonary disease (COPD) is a heterogeneous disorder with multiple disease subtypes. Candidate gene studies have found genetic associations for COPD-related phenotypes that may be relevant for pharmacogenetics studies, including lung function decline and COPD exacerbations. However, few COPD pharmacogenetics studies have been completed. Most studies have focused on the role of variants in the beta(2)-adrenergic receptor gene on bronchodilator response, but the findings have been inconclusive. Candidate gene studies highlight the concept that genes for COPD susceptibility may also be relevant in COPD pharmacogenetics. Currently, there are no clinical applications of pharmacogenetics to COPD therapy, but the use of pharmacogenetics to determine initial smoking cessation therapy may be closer to clinical application.

Biologic lung volume reduction in advanced upper lobe emphysema: phase 2 results

RATIONALE

Biologic lung volume reduction (BioLVR) is a new endobronchial treatment for advanced emphysema that reduces lung volume through tissue remodeling.

OBJECTIVES

Assess the safety and therapeutic dose of BioLVR hydrogel in upper lobe predominant emphysema.

METHODS

Open-labeled, multicenter phase 2 dose-ranging studies were performed with BioLVR hydrogel administered to eight subsegmental sites (four in each upper lobe) involving: (1) low-dose treatment (n = 28) with 10 ml per site (LD); and (2) high-dose treatment (n = 22) with 20 ml per site (HD). Safety was assessed by the incidence of serious medical complications. Efficacy was assessed by change from baseline in pulmonary function tests, dyspnea score, 6-minute walk distance, and health-related quality of life.

MEASUREMENTS AND MAIN RESULTS

After treatment there were no deaths and four serious treatment-related complications. A reduction in residual volume to TLC ratio at 12 weeks (primary efficacy outcome) was achieved with both LD (-6.4 +/- 9.3%; P = 0.002) and HD (-5.5 +/- 9.4%; P = 0.028) treatments. Improvements in pulmonary function in HD (6 mo: DeltaFEV(1) = +15.6%; P = 0.002; DeltaFVC = +9.1%; P = 0.034) were greater than in LD patients (6 mo: DeltaFEV(1) = +6.7%; P = 0.021; DeltaFVC = +5.1%; P = 0.139). LD- and HD-treated groups both demonstrated improved symptom scores and health-related quality of life.

CONCLUSIONS

BioLVR improves physiology and functional outcomes up to 6 months with an acceptable safety profile in upper lobe predominant emphysema. Overall improvement was greater and responses more durable with 20 ml per site than 10 ml per site dosing. Clinical trial registered with www.clinicaltrials.gov (NCT 00435253 and NCT 00515164).

Radiographic evaluation of the potential lung volume reduction surgery candidate

Delineating the extent and distribution of emphysema is an essential component of the evaluation of candidates for lung volume reduction surgery (LVRS). Imaging also may identify contraindications to LVRS, including bronchiectasis and pleural scarring. The chest X-ray is of limited utility in LVRS evaluation. Chest computed tomography (CT) scanning is an essential component of the evaluation, demonstrating the presence of emphysema and its amount and distribution. Clinical experience has shown that a substantial minority of chest CT scans will also demonstrate pulmonary nodules, some of which represent lung cancers. Published series, including the National Emphysema Treatment Trial, consistently demonstrate that patients with upper lobe predominant or heterogeneous emphysema are most likely to benefit from LVRS. Heterogeneity and distribution can also be assessed by radionuclide ventilation perfusion scanning, but this modality adds little additional information to CT scanning.

Xenobiotic metabolizing enzyme gene polymorphisms predict response to lung volume reduction surgery

BACKGROUND

In the National Emphysema Treatment Trial (NETT), marked variability in response to lung volume reduction surgery (LVRS) was observed. We sought to identify genetic differences which may explain some of this variability.

METHODS

In 203 subjects from the NETT Genetics Ancillary Study, four outcome measures were used to define response to LVRS at six months: modified BODE index, post-bronchodilator FEV1, maximum work achieved on a cardiopulmonary exercise test, and University of California, San Diego shortness of breath questionnaire. Sixty-four single nucleotide polymorphisms (SNPs) were genotyped in five genes previously shown to be associated with chronic obstructive pulmonary disease susceptibility, exercise capacity, or emphysema distribution.

RESULTS

A SNP upstream from glutathione S-transferase pi (GSTP1; p = 0.003) and a coding SNP in microsomal epoxide hydrolase (EPHX1; p = 0.02) were each associated with change in BODE score. These effects appeared to be strongest in patients in the non-upper lobe predominant, low exercise subgroup. A promoter SNP in EPHX1 was associated with change in BODE score (p = 0.008), with the strongest effects in patients with upper lobe predominant emphysema and low exercise capacity. One additional SNP in GSTP1 and three additional SNPs in EPHX1 were associated (p < 0.05) with additional LVRS outcomes. None of these SNP effects were seen in 166 patients randomized to medical therapy.

CONCLUSION

Genetic variants in GSTP1 and EPHX1, two genes encoding xenobiotic metabolizing enzymes, were predictive of response to LVRS. These polymorphisms may identify patients most likely to benefit from LVRS.

Biological lung volume reduction: a new bronchoscopic therapy for advanced emphysema

BACKGROUND

Biological lung volume reduction (BLVR) using biological reagents to remodel and shrink damaged regions of lung has previously been accomplished in sheep with experimental pulmonary emphysema. This report summarizes the initial clinical experience including a 3-month follow-up using this technique in humans.

METHODS

An open-label phase 1 trial designed to evaluate the safety of BLVR in patients with advanced heterogeneous emphysema enrolled six patients. Of these, three patients received unilateral treatment at two pulmonary subsegments (group 1) and three patients received unilateral treatment at four pulmonary subsegments (group 2). The incidence of adverse events and changes in pulmonary function test results, symptoms, and exercise capacity were evaluated.

RESULTS

The mean (+/- SD) age of the six men enrolled in the study was 66 +/- 5.7 years (age range, 57 to 73 years). BLVR was well tolerated in both treatment groups and was not associated with any serious complications. All patients were discharged from the hospital on posttreatment day 1. Although the primary purpose of the study was to examine safety, improvements were observed in mean vital capacity (+7.2 +/- 9.5%; range, -2% to + 19%), mean residual volume (RV) [-7.8 +/- 8.5%; range, + 1% to -22%], mean RV/total lung capacity ratio (-6.6 +/- 4.7%; range, -1% to -15%), mean 6-min walk distance (+14.5 +/- 18.5%; range, 0 to + 51%), and in mean dyspnea score. On average, group 2 patients experienced greater benefit from BLVR than group 1 patients, suggesting a dose-response pattern.

CONCLUSIONS

Preliminary results indicate that BLVR can be safe and may produce benefits in appropriately selected patients with advanced heterogeneous emphysema.

Interobserver Variability in the Determination of Upper Lobe-Predominant Emphysema

BACKGROUND

Appropriateness for lung volume reduction surgery is often determined based on the results of high-resolution CT (HRCT) scanning of the chest. At many centers, radiologists and pulmonary physicians both review the images, but the agreement between readers from these specialties is not known.

METHODS

Two thoracic radiologists and three pulmonologists retrospectively reviewed the HRCT scans of 30 patients with emphysema involved in two clinical studies at our institution. Each reader assigned an emphysema severity score and assessed upper lobe predominance, using a methodology similar to that of the National Emphysema Treatment Trial. In addition, the percentage of emphysema at -910 Hounsfield units was objectively determined by density mask analysis.

RESULTS

For the emphysema severity scores, (Spearman) correlation between readers ranged from 0.59 (p = 0.0005) to 0.87 (p < 0.0001), with generally stronger correlations among readers from the same medical specialty. Emphysema severity scores were significantly correlated with prebronchodilator and postbronchodilator spirometry findings, as well as with density mask analysis. In the assessment of upper lobe predominance, kappa statistics for agreement ranged from 0.20 (p = 0.4) to 0.60 (p = 0.0008). Examining all possible radiologist-pulmonologist pairs, the two readers agreed in their assessments of emphysema distribution in 75% of the comparisons. Readers agreed on upper lobe-predominant disease in 9 of the 10 patients in which regional density mask analysis clearly showed upper lobe predominance.

CONCLUSIONS

In a group of patients with varying emphysema severity, interobserver agreement in the determination of upper lobe-predominant disease was poor. Agreement between readers tended to be better in cases with clear upper lobe predominance as determined by densitometry.