High prevalence of emphysema and its association with BMI: a study of smokers with normal spirometry

Artificial Intelligence-Based Emphysema Quantification in Routine Chest Computed Tomography: Correlation With Spirometry and Visual Emphysema Grading

OBJECTIVE

The aim of the study is to assess the correlation between artificial intelligence (AI)-based low attenuation volume percentage (LAV%) with forced expiratory volume in the first second to forced vital capacity (FEV1/FVC) and visual emphysema grades in routine chest computed tomography (CT). Furthermore, optimal LAV% cutoff values for predicting a FEV1/FVC < 70% or moderate to more extensive visual emphysema grades were calculated.

METHODS

In a retrospective study of 298 consecutive patients who underwent routine chest CT and spirometry examinations, LAV% was quantified using an AI-based software with a threshold < -950 HU. The FEV1/FVC was derived from spirometry, with FEV1/FVC < 70% indicating airway obstruction. The mean time interval of CT from spirometry was 3.87 ± 4.78 days. Severity of emphysema was visually graded by an experienced chest radiologist using an established 5-grade ordinal scale (Fleischner Society classification system). Spearman correlation coefficient between LAV% and FEV1/FVC was calculated. Receiver operating characteristic determined the optimal LAV% cutoff values for predicting a FEV1/FVC < 70% or a visual emphysema grade of moderate or higher (Fleischner grade 3-5).

RESULTS

Significant correlation between LAV% and FEV1/FVC was found (ϱ = -0.477, P < 0.001). Increasing LAV% corresponded to higher visual emphysema grades. For patients with absent visual emphysema, mean LAV% was 2.98 ± 3.30, for patients with trace emphysema 3.22 ± 2.75, for patients with mild emphysema 3.90 ± 3.33, for patients with moderate emphysema 6.41 ± 3.46, for patients with confluent emphysema 9.02 ± 5.45, and for patients with destructive emphysema 16.90 ± 8.19. Optimal LAV% cutoff value for predicting a FEV1/FVC < 70 was 6.1 (area under the curve = 0.764, sensitivity = 0.773, specificity = 0.665), while for predicting a visual emphysema grade of moderate or higher, it was 4.7 (area under the curve = 0.802, sensitivity = 0.766, specificity = 0.742). Furthermore, correlation between visual emphysema grading and FEV1/FVC was found. In patients with FEV1/FVC < 70% a high proportion of subjects had emphysema grade 3 (moderate) or higher, whereas in patients with FEV1/FVC ≥ 70%, a larger proportion had emphysema grade 3 (moderate) or lower. The sensitivity for visual emphysema grading predicting a FEV1/FVC < 70% was 56.3% with an optimal cutoff point at a visual grade of 4 (confluent), demonstrating a lower sensitivity compared with LAV% (77.3%).

CONCLUSIONS

A significant correlation between AI-based LAV% and FEV1/FVC as well as visual CT emphysema grades can be found in routine chest CT suggesting that AI-based LAV% measurement might be integrated as an add-on functional parameter in the evaluation of chest CT in the future.

NSCLC patients with a changing T grade after operation may represent a special subset of tumor staging

BACKGROUND

There is consensus that postoperative adjuvant therapy is not recommended in patients with stage 1a non-small cell lung cancer (NSCLC). Meanwhile, it is still controversial whether postoperative adjuvant chemotherapy is recommended for NSCLC patients with T2aN0M0 (stage 1b). In some patients with stage 1b NSCLC without pleural invasion, tumor diameter was measured between 3 and 4 cm by preoperative imaging and less than 3 cm by postoperative pathology specimens. TNM staging in such patients is both radiologic stage 1b and pathologic stage 1a. Thoracic surgeons are often confused about whether such patients with NSCLC will require subsequent treatment and how the survival prognosis for this group of patients will be.

METHODS

All data of radiographic TNM stage 1b patients who underwent radical R0 resection at the department of thoracic surgery, the First Affiliated Hospital of Soochow University between January 2013 and July 2017 were retrieved, and 208 patients were finally included in the study. Clinical data, including imaging data, pathology data, were obtained by reviewing the patients' electronic medical records. Disease-free survival (DFS) and overall survival (OS) were obtained by telephone interview. Statistical analysis was performed using SPSS (SPSS 26.0 for windows, SPSS).

RESULTS

A total of 208 patients were included in this study, 61 patients with T-stage migration (observation group) and 147 patients without T-stage migration (control group). There were significant statistical differences between the two groups in terms of preoperative FEV1/FVC and tumor diameter (specimens, CT and 3-dimensional measurements). Logistic regression results showed that lower FEV1/FVC and smaller CT measurements would make the patient's T stage more likely to migrate. Bland-Altman plots showed that tumor length measured by imaging was significantly higher than that measured by pathological specimens. Taking DFS as the outcome, the survival curve of the observation group was significantly better than that of the control group. Similarly, there was a significant difference in OS between the two groups.

CONCLUSIONS

For NSCLC patients whose preoperative imaging evaluation was stage 1b (tumor diameter more than 3 cm, no main bronchus, pleura, no atelectasis), the presence of lung tissue with smaller tumor diameter and/or higher air content may indicate that the postoperative pathological staging may be changed to stage 1a (tumor diameter less than 3 cm). These patients had better survival prognosis than those who did not undergo TNM stage change and were diagnosed with stage 1b non-small cell lung cancer before and after surgery.

Quantitative Computed Tomography (CT) Assessment of Emphysema in Patients with Severe Chronic Obstructive Pulmonary Disease (COPD) and its Correlation with Age, Sex, Pulmonary Function Tests, BMI, Smoking, and Biomass Exposure

Background

To evaluate the role of HRCT in quantifying emphysema in severe COPD patients and to study the variations in the pattern of emphysema in relation to age, sex, FEV1, smoking index, biomass exposure, and BMI.

Material/Methods

Automatic lung segmentation of HRCT scans in 41 severe COPD patients (GOLD stage III or more) was done using an emphysema protocol. The extent of emphysema was assessed using the density mask method with a threshold of –950 HU (%LAA-950). The percentage of emphysema in each lung lobe and both lungs was correlated with 6 parameters – age, sex, BMI, smoking index, biomass exposure, and FEV₁.

Results

Smoking resulted in homogenously distributed emphysema regardless of the severity of smoking. BMI was inversely correlated with the extent of emphysema. A significant association was found between the percentage of emphysema in the right lower lobe and BMI (P=0.015), between biomass exposure and the percentage of emphysema in RUL, RLL, and both lungs (P values of 0.024, 0.016, and 0.036, respectively). The extent of emphysema was disproportionately low compared to the amount of obstruction on PFTs, indicating an airway predominant variety of COPD with significant biomass exposure.

Conclusions

Smoking is associated with a relatively homogenous distribution of emphysema with no regional predilection. Biomass exposure produces predominantly right-sided emphysema. BMI decreases with increasing levels of emphysema in the right lower lobe. These risk factors of emphysema patterns are helpful in deciding on the management, including surgical options.

Lobar Emphysema Distribution Is Associated With 5-Year Radiological Disease Progression

BACKGROUND

Emphysema has considerable variability in its regional distribution. Craniocaudal emphysema distribution is an important predictor of the response to lung volume reduction. However, there is little consensus regarding how to define upper lobe-predominant and lower lobe-predominant emphysema subtypes. Consequently, the clinical and genetic associations with these subtypes are poorly characterized.

METHODS

We sought to identify subgroups characterized by upper-lobe or lower-lobe emphysema predominance and comparable amounts of total emphysema by analyzing data from 9,210 smokers without alpha-1-antitrypsin deficiency in the Genetic Epidemiology of COPD (COPDGene) cohort. CT densitometric emphysema was measured in each lung lobe. Random forest clustering was applied to lobar emphysema variables after regressing out the effects of total emphysema. Clusters were tested for association with clinical and imaging outcomes at baseline and at 5-year follow-up. Their associations with genetic variants were also compared.

RESULTS

Three clusters were identified: minimal emphysema (n = 1,312), upper lobe-predominant emphysema (n = 905), and lower lobe-predominant emphysema (n = 796). Despite a similar amount of total emphysema, the lower-lobe group had more severe airflow obstruction at baseline and higher rates of metabolic syndrome compared with subjects with upper-lobe predominance. The group with upper-lobe predominance had greater 5-year progression of emphysema, gas trapping, and dyspnea. Differential associations with known COPD genetic risk variants were noted.

CONCLUSIONS

Subgroups of smokers defined by upper-lobe or lower-lobe emphysema predominance exhibit different functional and radiological disease progression rates, and the upper-lobe predominant subtype shows evidence of association with known COPD genetic risk variants. These subgroups may be useful in the development of personalized treatments for COPD.

Emphysema prevalence related air pollution caused by a cement plant

Background

To identify adverse pulmonary health effects due to air pollution derived from a cement plant in Korea. The emphysema prevalence in residents around a cement plant was compared to that in the group who live far away from the plant by chest films (PA and lateral view) and high-resolution computed tomography (HRCT) lung images.

Methods

From June to August in 2013 and from August to November in 2014, chest films and HRCT scan were conducted on residents over the age of 40 who lived around a cement plant. The residents were divided into two groups; a “more exposed group (MEG)” which consisted of 1,046 people who lived within a 1 km radius and a “less exposed group (LEG)” which consisted of 317 people who lived more than 5 km away from the same plant. We compared the emphysema prevalence and estimated the OR of this between the MEG and the LEG by using a chi-square and logistic regression on chest films and HRCT.

Results

The emphysema prevalence was 9.1 % in the LEG, 14.3 % in the MEG on chest films and 11.4 %, 17.8 % on the HRCT, respectively. The OR of the emphysema prevalence in MEG was 2.92 (95 % CI 1.77-4.83) on the chest films, 2.56 (95 % CI 1.64–3.99) on the HRCT after sex, age, body mass index (BMI), smoking history, residency period and firewood used history were adjusted. The OR in the less than 29 pack-years smoking history was 1.66 (95 % CI 0.92–3.06) and in the more than 30 pack-years was 3.05 (95 % CI 1.68–5.52) on the chest films, and was 1.68 (95 % CI 0.98–2.90), 2.93 (95 % CI 1.72–4.98) on the HRCT, respectively.

Conclusion

The emphysema prevalence seems to be affected by the level of exposure to air pollution derived from the cement plant as well as sex, age, BMI, and smoking history in this study. Moreover, the OR of the case of the more exposed to the air pollution was similar to that of the case in smoking.

A Genome-Wide Association Study of Emphysema and Airway Quantitative Imaging Phenotypes

RATIONALE

Chronic obstructive pulmonary disease (COPD) is defined by the presence of airflow limitation on spirometry, yet subjects with COPD can have marked differences in computed tomography imaging. These differences may be driven by genetic factors. We hypothesized that a genome-wide association study (GWAS) of quantitative imaging would identify loci not previously identified in analyses of COPD or spirometry. In addition, we sought to determine whether previously described genome-wide significant COPD and spirometric loci were associated with emphysema or airway phenotypes.

OBJECTIVES

To identify genetic determinants of quantitative imaging phenotypes.

METHODS

We performed a GWAS on two quantitative emphysema and two quantitative airway imaging phenotypes in the COPDGene (non-Hispanic white and African American), ECLIPSE (Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints), NETT (National Emphysema Treatment Trial), and GenKOLS (Genetics of COPD, Norway) studies and on percentage gas trapping in COPDGene. We also examined specific loci reported as genome-wide significant for spirometric phenotypes related to airflow limitation or COPD.

MEASUREMENTS AND MAIN RESULTS

The total sample size across all cohorts was 12,031, of whom 9,338 were from COPDGene. We identified five loci associated with emphysema-related phenotypes, one with airway-related phenotypes, and two with gas trapping. These loci included previously reported associations, including the HHIP, 15q25, and AGER loci, as well as novel associations near SERPINA10 and DLC1. All previously reported COPD and a significant number of spirometric GWAS loci were at least nominally (P < 0.05) associated with either emphysema or airway phenotypes.

CONCLUSIONS

Genome-wide analysis may identify novel risk factors for quantitative imaging characteristics in COPD and also identify imaging features associated with previously identified lung function loci.

Pulmonary function parameters in high-resolution computed tomography phenotypes of chronic obstructive pulmonary disease

BACKGROUND

Heterogeneity of clinical presentation of chronic obstructive pulmonary disease (COPD) attributes to different pathological basis. High-resolution computed tomography (HRCT) phenotypes of COPD may reflex the pathological basis of COPD indirectly by evaluating the small airway inflammation and emphysema. How the pulmonary function related with different HRCT phenotypes has not been well known. The aim was to explore the features of pulmonary function parameters in the 3 phenotypes.

METHODS

Sixty-three stable COPD patients were allocated in 3 groups based on HRCT findings: phenotype A (absence of emphysema, with minimal evidence of emphysema with or without bronchial wall thickening [BWT]), phenotype E (emphysema without BWT) and phenotype M (emphysema with BWT). The pulmonary function testing was also analyzed.

RESULTS

The values of forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC%), FEV1% and maximum expiratory flows (MEF)50% were the highest in phenotype A (P < 0.05), so was residual volume (RV)/total lung capacity (TLC%) in phenotype E (P < 0.05). Those with MEF50/MEF25 ratio >4.0 were more prevalence in phenotype A than in E and M (odds ratio = 2.214; P < 0.05). The occurrences of RV/TLC% >40% were higher in phenotype E than in A and M (odds ratio = 3.906; P < 0.05). Receiver operating characteristic analysis showed that the cutoff value of MEF50/MEF25 ratio for identifying phenotype A was 2.5, with sensitivity 66.7% and specificity 92.9%. The cutoff value of RV/TLC% for identifying phenotype E was 57.4%, with sensitivity 75.0% and specificity 79.1%.

CONCLUSIONS

The different features of pulmonary function parameters were found in various HRCT phenotypes; MEF50/MEF25 ratio could imply phenotype A, whereas RV/TLC% may be the indicator of phenotype E.

Clinical characteristics of COPD syndrome: A 6-year follow-up study of adult smokers

BACKGROUND

There is little quantitative information about the development of chronic obstructive pulmonary disease (COPD) among adult smokers and of what happens to patients who have already developed COPD.

OBJECTIVES

To examine the development and performance of COPD status over time, and the clinical characteristics of new COPD cases according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2007 and 2011 classifications.

METHODS

Healthy asymptomatic smokers were recruited through newspaper announcements. They filled in questionnaires and had an individualized assessment of their health history during all three visits (visit 1, visit 2 after three years, visit 3 after six years).

RESULTS

Of the eligible 621 heavy smokers, 572 attended visit 2. A total of 513 subjects completed the 6-year follow-up examination. According to GOLD 2007, COPD was present in 22.8% (n = 117) of these smokers. The severity of COPD changed during the years of follow-up. Furthermore, health status and prevalence of chronic respiratory symptoms both in the smokers with normal lung function and in the COPD groups varied over the time period.

CONCLUSIONS

GOLD 2011 recognized the complex patient subgroups better than GOLD 2007. Variability in chronic symptoms or in health status correlated poorly with the severity of airway limitation.

Are airflow obstruction and radiographic evidence of emphysema risk factors for lung cancer? A nested case-control study using quantitative emphysema analysis

OBJECTIVES

Several studies have identified airflow obstruction as a risk factor for lung cancer independent of smoking history, but the risk associated with the presence of radiographic evidence of emphysema has not been extensively studied. We proposed to assess this risk using a quantitative volumetric CT scan analysis.

METHODS

Sixty-four cases of lung cancer were identified from a prospective cohort of 1,520 participants enrolled in a spiral CT scan lung cancer screening trial. Each case was matched to six control subjects for age, sex, and smoking history. Quantitative CT scan analysis of emphysema was performed. Spirometric measures were also conducted. Data were analyzed using conditional logistic regression making use of the 1:6 set groups of 64 cases and 377 matched control subjects.

RESULTS

Decreased FEV(1) and FEV(1)/FVC were significantly associated with a diagnosis of lung cancer with ORs of 1.15 (95% CI, 1.00-1.32; P = .046) and 1.29 (95% CI, 1.02-1.62; P = .031), respectively. The quantity of radiographic evidence of emphysema was not found to be a significant risk for lung cancer with OR of 1.042 (95% CI, 0.816-1.329; P = .743). Additionally, there was no significant association between severe emphysema and lung cancer with OR of 1.57 (95% CI, 0.73-3.37).

CONCLUSIONS

We confirm previous observations that airflow obstruction is an independent risk factor for lung cancer. The absence of a clear relationship between radiographic evidence of emphysema and lung cancer using an automated quantitative volumetric analysis may result from different population characteristics than those of prior studies, radiographic evidence of emphysema quantitation methodology, or absence of any relationship between emphysema and lung cancer risk.

Early detection of COPD combined with individualized counselling for smoking cessation: a two-year prospective study

OBJECTIVE

Though the prevalence of COPD is related to the definition, even with this proviso COPD remains under-diagnosed. Screening can detect many new COPD cases, but its effects on smoking cessation remain unknown.

DESIGN

To evaluate symptoms in "healthy" cigarette smokers, to screen new COPD cases using international and national guidelines, and to assess the success of a smoking cessation.

SUBJECTS

Healthy asymptomatic smokers with a >20 pack-years smoking history were recruited. The first visit included a standardized personal interview, Fagerstom nicotine dependence test (FNDT) and individualized smoking counselling by Motivational Interviewing. At the follow-up visit two years later, the same analyses were repeated and smoking status assessed. To avoid bias in the counselling attributable to spirometry, the test was evaluated at the two-year follow-up assessment.

RESULTS

Almost all, 93.2%, of 584 participants attended the second visit. Spirometry revealed COPD by GOLD criteria in 11.0% and by national guidelines in 15.3%, mid-expiratory flow (MEF50) had significantly declined in 19.5%, chronic cough or sputum production was detected in 62% of the subjects. After two years, 23.3% had succeeded in giving up smoking. There were four predictors of successful quitting, i.e. positive attitude to the intervention, pharmacotherapy, older age, and higher BMI, whereas other factors such as cough, obstruction, gender, pack-years, or nicotine dependence showed no association with ability to achieve successful cessation.

CONCLUSION

Significant numbers of "healthy" smokers experience symptoms, according to detailed questionnaires, and have COPD. Motivation is the most significant factor in determining the chance of stopping smoking.

Sputum colour for diagnosis of a bacterial infection in patients with acute cough

OBJECTIVE

Sputum colour plays an important role in the disease concepts for acute cough, both in the patients' and the doctors' view. However, it is unclear whether the sputum colour can be used for diagnosis of a bacterial infection.

DESIGN

Cross-sectional study.

SETTING

A total of 42 GP practices in Dusseldorf, Germany.

SUBJECTS

Sputum samples obtained from 241 patients suffering from an episode of acute cough seeing their doctor within a routine consultation.

MAIN OUTCOME MEASURES

Relation of sputum colour and microbiological proof of bacterial infection defined as positive culture and at least a moderate number of leucocytes per low magnification field.

RESULTS

In 28 samples (12%) a bacterial infection was proven. Yellowish or greenish colour of the sputum sample and bacterial infection showed a significant correlation (p = 0.014, Fisher's exact test). The sensitivity of yellowish or greenish sputum used as a test for a bacterial infection was 0.79 (95% CI 0.63-0.94); the specificity was 0.46 (95% CI 0.038-0.53). The positive likelihood-ratio (+LR) was 1.46 (95% CI 1.17-1.85).

CONCLUSIONS

The sputum colour of patients with acute cough and no underlying chronic lung disease does not imply therapeutic consequences such as prescription of antibiotics.