Cigarette smoking is associated with subclinical parenchymal lung disease: the Multi-Ethnic Study of Atherosclerosis (MESA)-lung study

Interstitial Lung Abnormalities: Current Understanding

Interstitial lung abnormalities (ILAs) are incidental findings on computed tomography scans, characterized by nondependent abnormalities affecting more than 5% of any lung zone. They are associated with factors such as age, smoking, genetic variants, worsened clinical outcomes, and increased mortality. Risk stratification based on clinical and radiological features of ILAs is crucial in clinical practice, particularly for identifying cases at high risk of progression to pulmonary fibrosis. Traction bronchiectasis/bronchiolectasis index has emerged as a promising imaging biomarker for prognostic risk stratification in ILAs. These findings suggest a spectrum of fibrosing interstitial lung diseases, encompassing from ILAs to pulmonary fibrosis.

Determination of pulmonary vessel alteration in Chinese male smokers by quantitative computed tomography measurements: a retrospective study

Background

The blood volume of intraparenchymal vessels is reported to be increased in smokers. However, the blood volume can be affected by many confounders besides tobacco exposure. This study aimed to investigate the association between cigarette smoking and pulmonary blood volume after adjusting the related factors in a large cohort of Chinese males.

Methods

In this retrospective study, male participants admitted to the First Affiliated Hospital of Xi'an Jiaotong University for annual health assessment between February 2017 and February 2018 were enrolled. All subjects underwent non-contrast chest computed tomography (CT) scans, and 152 subjects underwent a review CT scan 2-3 years later. A three-dimensional approach was employed to segment the lung and intrapulmonary vessels and quantitative CT (QCT) measurements, including lung volume (LV), intrapulmonary vessel volume (IPVV), low-attenuation area <-950 Hounsfield unit (LAA-950 and LAA-950%), and mean lung density (MLD). Linear regression was used to estimate the association between IPVV and the smoking index (SI). A paired t-test was used to compare the QCT parameters between the initial and follow-up CT scans.

Results

A total of 656 male participants were enrolled and classified into three subgroups: non-smokers (n=311), current smokers (n=267), and former smokers (n=78). The IPVV of current smokers (134.62±23.96 vs. 120.76±25.52 mL) and former smokers (130.79±25.13 vs. 120.76±25.52 mL) were significantly larger than that of non-smokers (P<0.05). A higher SI was associated with greater IPVV [non-standardized coefficient: 0.167, 95% confidence interval (CI): 0.086-0.248]. For current smokers, the IPVV of the follow-up scan significantly increased compared to its baseline scan (135.49±28.60 vs. 129.73±29.75 mL, t=-2.326, P=0.02), but for the non-smokers and former smokers, the IPVV of the follow-up scan did not increase or decrease compared to the baseline scan (P>0.05).

Conclusions

Pulmonary vascular volumes detectable on non-contrast CT are associated with cigarette exposure, and smoking cessation may prevent pulmonary vasculature remodeling.

Interstitial lung disease: a review of classification, etiology, epidemiology, clinical diagnosis, pharmacological and non-pharmacological treatment

Interstitial lung diseases (ILDs) refer to a heterogeneous and complex group of conditions characterized by inflammation, fibrosis, or both, in the interstitium of the lungs. This results in impaired gas exchange, leading to a worsening of respiratory symptoms and a decline in lung function. While the etiology of some ILDs is unclear, most cases can be traced back to factors such as genetic predispositions, environmental exposures (including allergens, toxins, and air pollution), underlying autoimmune diseases, or the use of certain medications. There has been an increase in research and evidence aimed at identifying etiology, understanding epidemiology, improving clinical diagnosis, and developing both pharmacological and non-pharmacological treatments. This review provides a comprehensive overview of the current state of knowledge in the field of interstitial lung diseases.

Interstitial Lung Abnormality in Asian Population

Interstitial lung abnormalities (ILAs) are radiologic abnormalities found incidentally on chest computed tomography (CT) that can be show a wide range of diseases, from subclinical lung fibrosis to early pulmonary fibrosis including definitive usual interstitial pneumonia. To clear up confusion about ILA, the Fleischner society published a position paper on the definition, clinical symptoms, increased mortality, radiologic progression, and management of ILAs based on several Western cohorts and articles. Recently, studies on long-term outcome, risk factors, and quantification of ILA to address the confusion have been published in Asia. The incidence of ILA was 7% to 10% for Westerners, while the prevalence of ILA was about 4% for Asians. ILA is closely related to various respiratory symptoms or increased rate of treatment-related complication in lung cancer. There is little difference between Westerners and Asians regarding the clinical importance of ILA. Although the role of quantitative CT as a screening tool for ILA requires further validation and standardized imaging protocols, using a threshold of 5% in at least one zone demonstrated 67.6% sensitivity, 93.3% specificity, and 90.5% accuracy, and a 1.8% area threshold showed 100% sensitivity and 99% specificity in South Korea. Based on the position paper released by the Fleischner society, I would like to report how much ILA occurs in the Asian population, what the prognosis is, and review what management strategies should be pursued in the future.

KRASG12C Inhibitor as a Treatment Option for Non-Small-Cell Lung Cancer with Comorbid Interstitial Pneumonia

Non-small-cell lung cancer (NSCLC) with comorbid interstitial pneumonia (IP) is a population with limited treatment options and a poor prognosis. Patients with comorbid IP are at high risk of developing fatal drug-induced pneumonitis, and data on the safety and efficacy of molecularly targeted therapies are lacking. KRAS mutations have been frequently detected in patients with NSCLC with comorbid IP. However, the low detection rate of common driver gene mutations, such as epidermal growth factor receptor and anaplastic lymphoma kinase, in patients with comorbid IP frequently results in inadequate screening for driver mutations, and KRAS mutations may be overlooked. Recently, sotorasib and adagrasib were approved as treatment options for advanced NSCLC with KRASG12C mutations. Although patients with comorbid IP were not excluded from clinical trials of these KRASG12C inhibitors, the incidence of drug-induced pneumonitis was low. Therefore, KRASG12C inhibitors may be a safe and effective treatment option for NSCLC with comorbid IP. This review article discusses the promise and prospects of molecular-targeted therapies, especially KRASG12C inhibitors, for NSCLC with comorbid IP, along with our own clinical experience.

Longitudinal long term follow up investigation on the carcinogenic impact of polyhexamethylene guanidine phosphate in rat models

Polyhexamethylene guanidine phosphate (PHMG-p) is a major component in humidifier disinfectants, which cause life-threatening lung injuries. However, to our knowledge, no published studies have investigated associations between PHMG-p dose and lung damage severity with long-term follow-up. Therefore, we evaluated longitudinal dose-dependent changes in lung injuries using repeated chest computed tomography (CT). Rats were exposed to low (0.2 mg/kg, n = 10), intermediate (1.0 mg/kg, n = 10), and high (5.0 mg/kg, n = 10) doses of PHMG-p. All rats underwent repeated CT scans after 10 and 40 weeks following the first exposure. All CT images were quantitatively analyzed using commercial software. Inflammation/fibrosis and tumor counts underwent histopathological evaluation. In both radiological and histopathologic results, the lung damage severity increased as the PHMG-p dose increased. Moreover, the number, size, and malignancy of the lung tumors increased as the dose increased. Bronchiolar-alveolar hyperplasia developed in all groups. During follow-up, there was intergroup variation in bronchiolar-alveolar hyperplasia progression, although bronchiolar-alveolar adenomas or carcinomas usually increase in size over time. Thirty-three carcinomas were detected in the high-dose group in two rats. Overall, lung damage from PHMG-p and the number and malignancy of lung tumors were shown to be dose-dependent in a rat model using repeated chest CT scans during a long-term follow-up.

The impact of air pollution on interstitial lung disease: a systematic review and meta-analysis

Introduction

There is a growing body of evidence suggesting a causal relationship between interstitial lung disease (ILD) and air pollution, both for the development of the disease, and driving disease progression. We aim to provide a comprehensive literature review of the association between air pollution, and ILD, including idiopathic pulmonary fibrosis (IPF).

Methods

We systematically searched from six online database. Two independent authors (DL and CF) selected studies and critically appraised the risk of bias using the Newcastle-Ottawa Scale (NOS). Findings are presented through a narrative synthesis and meta-analysis. Meta-analyses were performed exclusively when there was a minimum of three studies examining identical pollutant-health outcome pairs, all evaluating equivalent increments in pollutant concentration, using a random effects model.

Results

24 observational studies conducted in 13 countries or regions were identified. Pollutants under investigation encompassed ozone (O3), nitrogen dioxide (NO2), Particulate matter with diameters of 10 micrometers or less (PM10) and 2.5 micrometers or less (PM2.5), sulfur dioxide (SO2), carbon monoxide (CO), nitric oxide (NO) and nitrogen oxides (NOx). We conducted meta-analyses to assess the estimated Risk Ratios (RRs) for acute exacerbations (AE)-IPF in relation to exposure to every 10 μg/m3 increment in air pollutant concentrations, including O3, NO2, PM10, and PM2.5. The meta-analysis revealed a significant association between the increased risk of AE-IPF in PM2.5, yielding RR 1.94 (95% CI 1.30-2.90; p = 0.001). Findings across all the included studies suggest that increased exposure to air pollutants may be linked to a range of health issues in individuals with ILDs.

Conclusion

A scarcity of available studies on the air pollutants and ILD relationship underscores the imperative for further comprehensive research in this domain. The available data suggest that reducing levels of PM2.5 in the atmosphere could potentially reduce AE frequency and severity in ILD patients.

Characteristics of Current Smokers versus Former Smokers with COPD and Their Associations with Smoking Cessation Within 4.5 Years: Results from COSYCONET

Background

Many patients with chronic obstructive pulmonary disease (COPD) continue smoking. We used data from the "real-life" COSYCONET COPD cohort to evaluate whether these patients differed from patients with COPD who either had ceased smoking prior to inclusion or ceased during the follow-up time of the study.

Methods

The analysis was based on data from visits 1-5 (covering 4.5 years), including all patients with the diagnosis of COPD who were either ex-smokers or smokers and categorized as GOLD 1-4 or the former GOLD 0 category. We compared the characteristics of smokers and ex-smokers at baseline (visit 1), as well as the course of lung function in the follow-up of permanent ex-smokers, permanent smokers and incident ex-smokers (smokers at visit 1 who ceased smoking before visit 5). We also identified baseline factors associated with subsequent smoking cessation.

Results

Among 2500 patients who were ever-smokers, 660 were current smokers and 1840 ex-smokers at baseline. Smokers were younger than ex-smokers (mean 61.5 vs 66.0 y), had a longer duration of smoking but fewer pack-years, a lower frequency of asthma, higher forced expiratory volume in 1 sec (FEV1, 59.4 vs 55.2% predicted) and higher functional residual capacity (FRC, 147.7 vs 144.3% predicted). Similar results were obtained for the longitudinal subpopulation, comprising 713 permanent ex-smokers, 175 permanent smokers, and 55 incident ex-smokers. When analyzing the time course of lung function, higher FRC, lower FEV1 and the presence of asthma (p < 0.05 each) were associated with incident cessation prior to visit 5, while less airway obstruction was associated with smoking continuation.

Conclusion

These findings, which were consistent in the cross-sectional and longitudinal analyses, suggest that lung hyperinflation was associated with being or becoming ex-smoker. Possibly, it is perceived by patients as one of the factors motivating their attempts to quit smoking, independent from airway obstruction.

Coronary artery calcium score is a prognostic factor for mortality in idiopathic pulmonary fibrosis

BACKGROUND

Cardiovascular diseases are frequent in idiopathic pulmonary fibrosis (IPF) and impact on survival. We investigated the association of coronary artery calcium (CAC) score at IPF diagnosis and during mid-term follow-up, with adverse cardiovascular events and all-cause mortality.

METHODS

Consecutive patients with IPF were retrospectively analyzed. Demographic data, smoking history, comorbidities and pulmonary function tests (PFTs) were recorded. All patients had at least two chest high resolution computed tomography (HRCT) performed 2 years apart. The total CAC score and visual fibrotic score were calculated, and all clinically significant cardiovascular events and deaths were reported.

RESULTS

The population consisted of 79 patients (57 males, mean age: 74.4±7.6 years); 67% of patients had a history of smoking, 48% of hypertension, 37% of dyslipidemia and 22.8% of diabetes. The visual score was 21.28±7.99% at T0 and 26.54±9.34% at T1, respectively (T1-T0 5.26±6.13%, P<0.001). CAC score at T0 and at T1 was 537.93±839.94 and 759.98±1027.6, respectively (T1-T0 224.66±406.87, P<0.001). Mean follow-up time was 2.47±1.1 years. On multivariate analysis, male sex (HR=3.58, 95% CI: 1.14-11.2) and CAC score at T0 (HR=1.04, 95% CI: 1.01-1.07) correlated with mortality and cardiovascular events. CAC score at T0≥405 showed 82% sensitivity and 100% specificity for predicting mortality and adverse cardiovascular events.

CONCLUSIONS

IPF patients with a CAC score at diagnosis ≥405 have a poor prognosis over a mid-term follow-up. A higher CAC score is associated with mortality and cardiovascular events.

Comparison of clinical scoring to predict mortality risk in mild-to-moderate idiopathic pulmonary fibrosis

BACKGROUND

During the last decade, a number of clinical scores, such as Gender-Age-Physiology (GAP) Index, TORVAN Score and Charlson Comorbidity Index (CCI), have been separately used to measure comorbidity burden in idiopathic pulmonary fibrosis (IPF). However, no previous study compared the prognostic value of these scores to assess mortality risk stratification in IPF patients with mild-to-moderate disease.

METHODS

All consecutive patients with mild-to-moderate IPF who underwent high-resolution computed tomography, spirometry, transthoracic echocardiography and carotid ultrasonography at our Institution, between January 2016 and December 2018, were retrospectively analyzed. GAP Index, TORVAN Score and CCI were calculated in all patients. Primary endpoint was all-cause mortality, whereas secondary endpoint was the composite of all-cause mortality and rehospitalizations for all-causes, over medium-term follow-up.

RESULTS

Seventy IPF patients (70.2±7.4 yrs, 74.3% males) were examined. At baseline, GAP Index, TORVAN Score and CCI were 3.4±1.1, 14.7±4.1 and 5.3±2.4, respectively. A strong correlation between coronary artery calcification (CAC) and common carotid artery (CCA) intima-media thickness (IMT) (r=0.88), CCI and CAC (r=0.80), CCI and CCA-IMT (r=0.81), was demonstrated in the study group. Follow-up period was 3.5±1.2 years. During follow-up, 19 patients died and 32 rehospitalizations were detected. CCI (HR 2.39, 95% CI: 1.31-4.35) and heart rate (HR 1.10, 95% CI: 1.04-1.17) were independently associated with primary endpoint. CCI (HR 1.54, 95% CI: 1.15-2.06) predicted secondary endpoint, also. A CCI ≥6 was the optimal cut-off for predicting both outcomes.

CONCLUSIONS

Due to the increased atherosclerotic and comorbidity burden, IPF patients with CCI ≥6 at an early-stage disease have poor outcome over medium-term follow-up.

Incidence of Interstitial Lung Abnormalities: The MESA Lung Study

The incidence of newly developed interstitial lung abnormalities (ILA) and fibrotic ILA have not been previously reported.Trained thoracic radiologists evaluated 13 944 cardiac CT scans for the presence of ILA in 6197 Multi-Ethnic Study of Atherosclerosis longitudinal cohort study participants >45 years of age from 2000 to 2012. 5% of the scans were re-read by the same or a different observer in a blinded fashion. After exclusion of participants with ILA at baseline, incidence rates and incidence rate ratios for ILA and fibrotic ILA were calculated.The intra-reader agreement of ILA was 92.0% (Gwet AC1=0.912, ICC=0.982) and the inter-reader agreement of ILA was 83.5% (Gwet AC1=0.814; ICC=0.969). Incidence of ILA and fibrotic ILA was estimated to be 13.1 cases/1000 person-years and 3.5/1000 person-years, respectively. In multivariable analyses, age (HR 1.06 (1.05, 1.08), p <0.001; HR 1.08 (1.06, 1.11), p <0.001), high attenuation area (HAA) at baseline (HR 1.05 (1.03, 1.07), p <0.001; HR 1.06 (1.02, 1.10), p=0.002), and the MUC5B promoter SNP (HR 1.73 (1.17, 2.56) p=0.01; HR 4.96 (2.68, 9.15), p <0.001) were associated with incident ILA and fibrotic ILA, respectively. Ever smoking (HR 2.31 (1.34, 3.96), p= 0.002) and an IPF polygenic risk score (HR 2.09 (1.61-2.71), p<0.001) were associated only with incident fibrotic ILA.Incident ILA and fibrotic ILA were estimated by review of cardiac imaging studies. These findings may lead to wider application of a screening tool for atherosclerosis to identify preclinical lung disease.

Cigarette Smoking, and Blood Monocyte Count Correlate with Chronic Lung Injuries and Mortality

Background

Cigarette smoking (CS)-related monocytosis contributes to the development of chronic lung injuries via complex mechanisms. We aim to determine correlations between measures of CS and monocytes, their capacities to predict chronic lung diseases, and their associations with mortality.

Methods

A single-center retrospective study of patients undergoing surgical resection for suspected lung nodules/masses was performed. CS was quantified as cigarettes smoked per day (CPD), duration of smoking, composite pack years (CPY), current smoking status, and smoking cessation years. A multivariate logistic regression analysis was performed.

Results

Of 382 eligible patients, 88% were ever smokers. In this group, 45% were current smokers with mean CPD of 27.2±40.0. CPY and duration of smoking showed positive linear correlations with percentage monocyte count. Physiologically, CPY was associated with progressive obstruction, hyperinflation, and reduced diffusion capacity (DL_CO). Across the quartiles of smoking, there was an accumulation of radiologic and histologic abnormalities. Anthracosis and emphysema were associated with CPD, while lung cancer, respiratory bronchiolitis (RB), emphysema, and honeycombing were statistically related to duration of smoking. Analysis using consecutive CPY showed associations with lung cancer (≥10 and <30), fibrosis (≥20 and <40), RB (≥50), anthracosis and emphysema (≥10 and onwards). Percentage monocytes correlated with organizing pneumonia (OP), fibrosis, and emphysema. The greater CPY increased mortality across the groups. Significant predictors of mortality included percentage monocyte, anemia, GERD, and reduced DL_CO.

Conclusion

Indices of CS and greater monocyte numbers were associated with endpoints of chronic lung disease suggesting a participation in pathogenesis. Application of these easily available metrics may support a chronology of CS-induced chronic lung injuries. While a relative lesser amount of smoking can be associated with lung cancer and fibrosis, greater CPY increases the risk for emphysema. Monocytosis predicted lung fibrosis and mortality. Duration of smoking may serve as a better marker of monocytosis and associated chronic lung diseases.

Impact of interstitial lung abnormalities on postoperative pulmonary complications and survival of lung cancer

BACKGROUND

Interstitial lung abnormalities (ILAs) are associated with the risk of lung cancer and its mortality. However, the impact of ILA on treatment-related complications and survival in patients who underwent curative surgery is still unknown.

RESEARCH QUESTION

This study aimed to evaluate the significance of the presence of computed tomography-diagnosed ILA and histopathologically matched interstitial abnormalities on postoperative pulmonary complications (PPCs) and the long-term survival of patients who underwent surgical treatment for lung cancer.

STUDY DESIGN AND METHODS

A matched case-control study was designed to compare PPCs and mortality among 50 patients with ILA, 50 patients with idiopathic pulmonary fibrosis (IPF) and 200 controls. Cases and controls were matched by sex, age, smoking history, tumour location, the extent of surgery, tumour histology and pathological TNM stage.

RESULTS

Compared with the control group, the OR of the prevalence of PPCs increased to 9.56 (95% CI 2.85 to 32.1, p<0.001) in the ILA group and 56.50 (95% CI 17.92 to 178.1, p<0.001) in the IPF group. The 5-year overall survival (OS) rates of the control, ILA and IPF groups were 76% (95% CI 71% to 83%), 52% (95% CI 37% to 74%) and 32% (95% CI 19% to 53%), respectively (log-rank p<0.001). Patients with ILA had better 5-year OS than those with IPF (log-rank p=0.046) but had worse 5-year OS than those in the control group (log-rank p=0.002).

CONCLUSIONS

The presence of radiological and pathological features of ILA in patients with lung cancer undergoing curative surgery was associated with frequent complications and decreased survival.

Prevalence and Long-term Outcomes of CT Interstitial Lung Abnormalities in a Health Screening Cohort

Background The association between interstitial lung abnormalities (ILAs) and long-term outcomes has not been reported in Asian health screening populations. Purpose To investigate ILA prevalence in an Asian health screening cohort and determine rates and risks for ILA progression, lung cancer development, and mortality within the 10-year follow-up. Materials and Methods This observational, retrospective multicenter study included patients aged 50 years or older who underwent chest CT at three health screening centers over a 4-year period (2007-2010). ILA status was classified as none, equivocal ILA, and ILA (nonfibrotic or fibrotic). Progression was evaluated from baseline to the last follow-up CT examination, when available. The log-rank test was performed to compare mortality rates over time between ILA statuses. Multivariable Cox proportional hazards models were used to assess factors associated with hazards of ILA progression, lung cancer development, and mortality. Results Of the 2765 included patients (mean age, 59 years ± 7 [SD]; 2068 men), 94 (3%) had a finding of ILA (35 nonfibrotic and 59 fibrotic ILA) and 119 (4%) had equivocal ILA. The median time for CT follow-up and the entire observation was 8 and 12 years, respectively. ILA progression was observed in 80% (48 of 60) of patients with ILA over 8 years. Those with fibrotic and nonfibrotic ILA had a higher mortality rate than those without ILA (P < .001 and P = .01, respectively) over 12 years. Fibrotic ILA was independently associated with ILA progression (hazard ratio [HR], 10.3; 95% CI: 6.4, 16.4; P < .001), lung cancer development (HR, 4.4; 95% CI: 2.1, 9.1; P < .001), disease-specific mortality (HR, 6.7; 95% CI: 3.7, 12.2; P < .001), and all-cause mortality (HR, 2.5; 95% CI: 1.6, 3.8; P < .001) compared with no ILA. Conclusion The prevalence of interstitial lung abnormalities (ILAs) in an Asian health screening cohort was approximately 3%, and fibrotic ILA was an independent risk factor for ILA progression, lung cancer development, and mortality. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Hatabu and Hata in this issue.

Quantitative Imaging Metrics for the Assessment of Pulmonary Pathophysiology: An Official American Thoracic Society and Fleischner Society Joint Workshop Report

Multiple thoracic imaging modalities have been developed to link structure to function in the diagnosis and monitoring of lung disease. Volumetric computed tomography (CT) renders three-dimensional maps of lung structures and may be combined with positron emission tomography (PET) to obtain dynamic physiological data. Magnetic resonance imaging (MRI) using ultrashort-echo time (UTE) sequences has improved signal detection from lung parenchyma; contrast agents are used to deduce airway function, ventilation-perfusion-diffusion, and mechanics. Proton MRI can measure regional ventilation-perfusion ratio. Quantitative imaging (QI)-derived endpoints have been developed to identify structure-function phenotypes, including air-blood-tissue volume partition, bronchovascular remodeling, emphysema, fibrosis, and textural patterns indicating architectural alteration. Coregistered landmarks on paired images obtained at different lung volumes are used to infer airway caliber, air trapping, gas and blood transport, compliance, and deformation. This document summarizes fundamental "good practice" stereological principles in QI study design and analysis; evaluates technical capabilities and limitations of common imaging modalities; and assesses major QI endpoints regarding underlying assumptions and limitations, ability to detect and stratify heterogeneous, overlapping pathophysiology, and monitor disease progression and therapeutic response, correlated with and complementary to, functional indices. The goal is to promote unbiased quantification and interpretation of in vivo imaging data, compare metrics obtained using different QI modalities to ensure accurate and reproducible metric derivation, and avoid misrepresentation of inferred physiological processes. The role of imaging-based computational modeling in advancing these goals is emphasized. Fundamental principles outlined herein are critical for all forms of QI irrespective of acquisition modality or disease entity.

Machine learning in radiology: the new frontier in interstitial lung diseases

Challenges for the effective management of interstitial lung diseases (ILDs) include difficulties with the early detection of disease, accurate prognostication with baseline data, and accurate and precise response to therapy. The purpose of this Review is to describe the clinical and research gaps in the diagnosis and prognosis of ILD, and how machine learning can be applied to image biomarker research to close these gaps. Machine-learning algorithms can identify ILD in at-risk populations, predict the extent of lung fibrosis, correlate radiological abnormalities with lung function decline, and be used as endpoints in treatment trials, exemplifying how this technology can be used in care for people with ILD. Advances in image processing and analysis provide further opportunities to use machine learning that incorporates deep-learning-based image analysis and radiomics. Collaboration and consistency are required to develop optimal algorithms, and candidate radiological biomarkers should be validated against appropriate predictors of disease outcomes.

Quantitative Interstitial Abnormality Progression and Outcomes in the Genetic Epidemiology of COPD and Pittsburgh Lung Screening Study Cohorts

BACKGROUND

The risk factors and clinical outcomes of quantitative interstitial abnormality progression over time have not been characterized.

RESEARCH QUESTIONS

What are the associations of quantitative interstitial abnormality progression with lung function, exercise capacity, and mortality? What are the demographic and genetic risk factors for quantitative interstitial abnormality progression?

STUDY DESIGN AND METHODS

Quantitative interstitial abnormality progression between visits 1 and 2 was assessed from 4,635 participants in the Genetic Epidemiology of COPD (COPDGene) cohort and 1,307 participants in the Pittsburgh Lung Screening Study (PLuSS) cohort. We used multivariable linear regression to determine the risk factors for progression and the longitudinal associations between progression and FVC and 6-min walk distance, and Cox regression models for the association with mortality.

RESULTS

Age at enrollment, female sex, current smoking status, and the MUC5B minor allele were associated with quantitative interstitial abnormality progression. Each percent annual increase in quantitative interstitial abnormalities was associated with annual declines in FVC (COPDGene: 8.5 mL/y; 95% CI, 4.7-12.4 mL/y; P < .001; PLuSS: 9.5 mL/y; 95% CI, 3.7-15.4 mL/y; P = .001) and 6-min walk distance, and increased mortality (COPDGene: hazard ratio, 1.69; 95% CI, 1.34-2.12; P < .001; PLuSS: hazard ratio, 1.28; 95% CI, 1.10-1.49; P = .001).

INTERPRETATION

The objective, longitudinal measurement of quantitative interstitial abnormalities may help identify people at greatest risk for adverse events and most likely to benefit from early intervention.

The Association between Exposures and Disease Characteristics in Familial Pulmonary Fibrosis

Rationale: Heterogeneous characteristics are observed in familial pulmonary fibrosis (FPF), suggesting that nongenetic factors contribute to disease manifestations. Objectives: To determine the relationship between environmental exposures and disease characteristics of FPF, including the morphological characteristics on chest computed tomography (CT) scan, and timing of FPF symptom onset, lung transplantation, or death. Methods: Subjects with FPF with an exposure questionnaire and chest CT were selected from a prospective cohort at Vanderbilt. Disease characteristics were defined by lung parenchymal findings on chest CT associated with fibrotic hypersensitivity pneumonitis (fHP) or usual interstitial pneumonia (UIP) and by time from birth to symptom onset or a composite of lung transplantation or death. After assessing the potential for confounding by sex or smoking, adjusted logistic or Cox proportional hazards regression models identified exposures associated with fHP or UIP CT findings. Findings were validated in a cohort of patients with sporadic pulmonary fibrosis enrolled in the LTRC (Lung Tissue Research Consortium) study. Results: Among 159 subjects with FPF, 98 (61.6%) were males and 96 (60.4%) were ever-smokers. Males were less likely to have CT features of fHP, including mosaic attenuation (FPF: adjusted [for sex and smoking] odds ratio [aOR], 0.27; 95% confidence interval [CI], 0.09-0.76; P = 0.01; LTRC: aOR, 0.35; 95% CI, 0.21-0.61; P = 0.0002). Organic exposures, however, were not consistently associated with fHP features in either cohort. Smoking was a risk factor for honeycombing in both cohorts (FPF: aOR, 2.19; 95% CI, 1.12-4.28; P = 0.02; LTRC: aOR, 1.69; 95% CI, 1.22-2.33; P = 0.002). Rock dust exposure may also be associated with honeycombing, although the association was not statistically-significant when accounting for sex and smoking (FPF: aOR, 2.27; 95% CI, 0.997-5.15; P = 0.051; LTRC: aOR, 1.51; 95% CI, 0.97-2.33; P = 0.07). In the FPF cohort, ever-smokers experienced a shorter transplant-free survival (adjusted hazard ratio, 1.64; 95% CI, 1.07-2.52; P = 0.02), whereas sex was not associated with differential survival (male adjusted hazard ratio, 0.75; 95% CI, 0.50-1.14; P = 0.18). Conclusions: In FPF, smoking contributes to shortened transplant-free survival and development of honeycombing, a finding that is also likely applicable to sporadic pulmonary fibrosis. Females are more likely to manifest CT features of fHP (mosaic attenuation), a finding that was incompletely explained by sex differences in exposures. These findings may have implications for pulmonary fibrosis classification and management.

Interstitial Lung Abnormalities in Patients With Locally Advanced Esophageal Cancer: Prevalence, Risk Factors, and Clinical Implications

PURPOSE

Interstitial lung abnormalities (ILAs) represent nondependent abnormalities on chest computed tomography (CT) indicating lung parenchymal damages due to inflammation and fibrosis. Interstitial lung abnormalities have been studied as a predictor of clinical outcome in lung cancer, but not in other thoracic malignancies. The present study investigated the prevalence of ILA in patients with esophageal cancer and identified risk factors and clinical implications of ILA in these patients.

METHODS

The study included 208 patients with locally advanced esophageal cancer (median age, 65.6 years; 166 males, 42 females). Interstitial lung abnormality was scored on baseline CT scans before treatment using a 3-point scale (0 = no evidence of ILA, 1 = equivocal for ILA, 2 = ILA). Clinical characteristics and overall survival were compared in patients with ILA (score 2) and others.

RESULTS

An ILA was present in 14 of 208 patients (7%) with esophageal cancer on pretreatment chest CT. Patients with ILA were significantly older (median age, 69 vs 65, respectively; P = 0.011), had a higher number of pack-years of smoking ( P = 0.02), and more commonly had T4 stage disease ( P = 0.026) than patients with ILA score of 1 or 0. Interstitial lung abnormality on baseline scan was associated with a lack of surgical resection after chemoradiotherapy (7/14, 50% vs 39/194, 20% respectively; P = 0.016). Interstitial lung abnormality was not associated with overall survival (log-rank P = 0.75, Cox P = 0.613).

CONCLUSIONS

An ILA was present in 7% of esophageal cancer patients, which is similar to the prevalence in general population and in smokers. Interstitial lung abnormality was strongly associated with a lack of surgical resection after chemoradiotherapy, indicating an implication of ILA in treatment selection in these patients, which can be further studied in larger cohorts.

Interstitial Lung Abnormalities at CT: Subtypes, Clinical Significance, and Associations with Lung Cancer

Interstitial lung abnormality (ILA) is defined as an interstitial change detected incidentally on CT images. It is seen in 4%-9% of smokers and 2%-7% of nonsmokers. ILA has a tendency to progress with time and is associated with respiratory symptoms, decreased exercise capability, reduced pulmonary function, and increased mortality. ILAs can be classified into three subcategories: nonsubpleural, subpleural nonfibrotic, and subpleural fibrotic. In cases of ILA, clinically significant interstitial lung disease should be identified and requires clinically driven management by a pulmonologist. Risk factors for the progression of ILA include clinical elements (ie, inhalation exposures, medication use, radiation therapy, thoracic surgery, physiologic findings, and gas exchange findings) and radiologic elements (ie, basal and peripheral predominance and fibrotic findings). It is recommended that individuals with one or more clinical or radiologic risk factors for progression of ILA be actively monitored with pulmonary function testing and CT. To avoid overcalling ILA at CT, radiologists must recognize the imaging pitfalls, including centrilobular nodularity, dependent abnormality, suboptimal inspiration, osteophyte-related lesions, apical cap and pleuroparenchymal fibroelastosis-like lesions, aspiration, and infection. There is a close association between ILA and lung cancer, and many studies have reported an increased incidence of lung cancer, worse prognoses, and/or increased pulmonary complications in relation to cancer treatment in patients with ILA. ILA is considered to be an important comorbidity in patients with lung cancer. Accordingly, all radiologists involved with body CT must have sound knowledge of ILAs owing to the high prevalence and potential clinical significance of these anomalies. An overview of ILAs, including a literature review of the associations between ILAs and lung cancer, is presented. ©RSNA, 2022.

Environmental and occupational exposures in interstitial lung disease

PURPOSE OF REVIEW

We highlight recent advances in the understanding of how environmental and occupational exposures increase the risk of developing interstitial lung disease (ILD), and how to evaluate a patient for potential exposures.

RECENT FINDINGS

A review of emerging literature suggests that environmental and occupational exposures can be directly causal, as in the case of the pneumoconioses and smoking-related ILDs, or one of many contributors to disease, as in the case of idiopathic pulmonary fibrosis (IPF). Regardless of the level of association, exposures are clearly prevalent across all ILD subtypes studied.

SUMMARY

Inhalational exposures are increasingly recognized as an important component in the development of ILDs, and novel exposure-disease associations continue to be discovered. These exposures represent potential opportunities for further understanding the pathobiology of disease and for the prevention of these often progressive and debilitating disorders. Prospective, comprehensive data collection regarding occupational and environmental exposures are needed in ILD patients to fully elucidate specific antigens and their relationships to disease incidence and outcomes. Systematically collected exposure information will also inform potential interventions to remediate exposures and thus mitigate the course of frequently progressive and fatal diseases.

How Artificial Intelligence in Imaging Can Better Serve Patients with Bronchial and Parenchymal Lung Diseases?

With the rapid development of computing today, artificial intelligence has become an essential part of everyday life, with medicine and lung health being no exception. Big data-based scientific research does not mean simply gathering a large amount of data and letting the machines do the work by themselves. Instead, scientists need to identify problems whose solution will have a positive impact on patients’ care. In this review, we will discuss the role of artificial intelligence from both physiological and anatomical standpoints, starting with automatic quantitative assessment of anatomical structures using lung imaging and considering disease detection and prognosis estimation based on machine learning. The evaluation of current strengths and limitations will allow us to have a broader view for future developments.

Syndrome of Combined Pulmonary Fibrosis and Emphysema: An Official ATS/ERS/JRS/ALAT Research Statement

Background: The presence of emphysema is relatively common in patients with fibrotic interstitial lung disease. This has been designated combined pulmonary fibrosis and emphysema (CPFE). The lack of consensus over definitions and diagnostic criteria has limited CPFE research. Goals: The objectives of this task force were to review the terminology, definition, characteristics, pathophysiology, and research priorities of CPFE and to explore whether CPFE is a syndrome. Methods: This research statement was developed by a committee including 19 pulmonologists, 5 radiologists, 3 pathologists, 2 methodologists, and 2 patient representatives. The final document was supported by a focused systematic review that identified and summarized all recent publications related to CPFE. Results: This task force identified that patients with CPFE are predominantly male, with a history of smoking, severe dyspnea, relatively preserved airflow rates and lung volumes on spirometry, severely impaired DlCO, exertional hypoxemia, frequent pulmonary hypertension, and a dismal prognosis. The committee proposes to identify CPFE as a syndrome, given the clustering of pulmonary fibrosis and emphysema, shared pathogenetic pathways, unique considerations related to disease progression, increased risk of complications (pulmonary hypertension, lung cancer, and/or mortality), and implications for clinical trial design. There are varying features of interstitial lung disease and emphysema in CPFE. The committee offers a research definition and classification criteria and proposes that studies on CPFE include a comprehensive description of radiologic and, when available, pathological patterns, including some recently described patterns such as smoking-related interstitial fibrosis. Conclusions: This statement delineates the syndrome of CPFE and highlights research priorities.

Assessing predictors of rheumatoid arthritis-associated interstitial lung disease using quantitative lung densitometry

OBJECTIVE

To assess predictors of subclinical RA-associated interstitial lung disease (RA-ILD) using quantitative lung densitometry (qLD).

METHODS

RA patients underwent multi-detector row CT scanning at baseline and after an average of 39 months. Scans were analysed with qLD for the percentage of lung parenchyma with high attenuation areas (%HAA: the percentage of voxels of -600 to -250 Hounsfield units). Additionally, a pulmonary radiologist calculated an expert radiologist scoring (ERS) for RA-ILD features. Generalized linear models were used to identify indicators of baseline %HAA and predictors of %HAA change.

RESULTS

Baseline %HAA was assessed in 193 RA patients and 106 had repeat qLD assessment. %HAA was correlated with ERS (Spearman's rho = 0.261; P < 0.001). Significant indicators of high baseline %HAA (>10% of lung parenchyma with high attenuation) included female sex, higher pack-years of smoking, higher BMI and anti-CCP ≥200 units, collectively contributing an area under the receiver operator curve of 0.88 (95% CI 0.81, 0.95). Predictors of %HAA increase, occurring in 49% with repeat qLD, included higher baseline %HAA, presence of mucin 5B (MUC5B) minor allele and absence of HLA-DRB1 shared epitope (area under the receiver operator curve = 0.69; 95% CI 0.58, 0.79). The association of the MUC5B minor allele with %HAA change was higher among men and those with higher cumulative smoking. Within the group with increased %HAA, anti-CCP level was significantly associated with a greater increase in %HAA.

CONCLUSIONS

%HAA, assessed with qLD, was linked to several known risk factors for RA-ILD and may represent a more quantitative method to identify RA-ILD and track progression than expert radiologist interpretation.

Incidental discovery of interstitial lung disease: diagnostic approach, surveillance and perspectives

The incidental discovery of pre-clinical interstitial lung disease (ILD) has led to the designation of interstitial lung abnormalities (ILA), a radiological entity defined as the incidental finding of computed tomography (CT) abnormalities affecting more than 5% of any lung zone. Two recent documents have redefined the borders of this entity and made the recommendation to monitor patients with ILA at risk of progression. In this narrative review, we will focus on some of the limits of the current approach, underlying the potential for progression to full-blown ILD of some patients with ILA and the numerous links between subpleural fibrotic ILA and idiopathic pulmonary fibrosis (IPF). Considering the large prevalence of ILA in the general population (7%), restricting monitoring only to cases considered at risk of progression appears a reasonable approach. However, this suggestion should not prevent pulmonary physicians from pursuing an early diagnosis of ILD and timely treatment where appropriate. In cases of suspected ILD, whether found incidentally or not, the pulmonary physician is still required to make a correct ILD diagnosis according to current guidelines, and eventually treat the patient accordingly.

In patients with interstitial lung abnormalities (ILA), monitoring of those at risk of progression is currently recommended, and pulmonary physicians should pursue an early diagnosis when ILA become clinically significant to facilitate timely treatment https://bit.ly/3HKOQc8

Blood gene expression risk profiles and interstitial lung abnormalities: COPDGene and ECLIPSE cohort studies

BACKGROUND

Interstitial lung abnormalities (ILA) are radiologic findings that may progress to idiopathic pulmonary fibrosis (IPF). Blood gene expression profiles can predict IPF mortality, but whether these same genes associate with ILA and ILA outcomes is unknown. This study evaluated if a previously described blood gene expression profile associated with IPF mortality is associated with ILA and all-cause mortality.

METHODS

In COPDGene and ECLIPSE study participants with visual scoring of ILA and gene expression data, we evaluated the association of a previously described IPF mortality score with ILA and mortality. We also trained a new ILA score, derived using genes from the IPF score, in a subset of COPDGene. We tested the association with ILA and mortality on the remainder of COPDGene and ECLIPSE.

RESULTS

In 1469 COPDGene (training n = 734; testing n = 735) and 571 ECLIPSE participants, the IPF score was not associated with ILA or mortality. However, an ILA score derived from IPF score genes was associated with ILA (meta-analysis of test datasets OR 1.4 [95% CI: 1.2-1.6]) and mortality (HR 1.25 [95% CI: 1.12-1.41]). Six of the 11 genes in the ILA score had discordant directions of effects compared to the IPF score. The ILA score partially mediated the effects of age on mortality (11.8% proportion mediated).

CONCLUSIONS

An ILA gene expression score, derived from IPF mortality-associated genes, identified genes with concordant and discordant effects on IPF mortality and ILA. These results suggest shared, and unique biologic processes, amongst those with ILA, IPF, aging, and death.

Quantitative Computed Tomography Parameters in Coronavirus Disease 2019 Patients and Prediction of Respiratory Outcomes Using a Decision Tree

Background

Chest computed tomography (CT) scans play an important role in the diagnosis of coronavirus disease 2019 (COVID-19). This study aimed to describe the quantitative CT parameters in COVID-19 patients according to disease severity and build decision trees for predicting respiratory outcomes using the quantitative CT parameters.

Methods

Patients hospitalized for COVID-19 were classified based on the level of disease severity: (1) no pneumonia or hypoxia, (2) pneumonia without hypoxia, (3) hypoxia without respiratory failure, and (4) respiratory failure. High attenuation area (HAA) was defined as the quantified percentage of imaged lung volume with attenuation values between −600 and −250 Hounsfield units (HU). Decision tree models were built with clinical variables and initial laboratory values (model 1) and including quantitative CT parameters in addition to them (model 2).

Results

A total of 387 patients were analyzed. The mean age was 57.8 years, and 50.3% were women. HAA increased as the severity of respiratory outcome increased. HAA showed a moderate correlation with lactate dehydrogenases (LDH) and C-reactive protein (CRP). In the decision tree of model 1, the CRP, fibrinogen, LDH, and gene Ct value were chosen as classifiers whereas LDH, HAA, fibrinogen, vaccination status, and neutrophil (%) were chosen in model 2. For predicting respiratory failure, the decision tree built with quantitative CT parameters showed a greater accuracy than the model without CT parameters.

Conclusions

The decision tree could provide higher accuracy for predicting respiratory failure when quantitative CT parameters were considered in addition to clinical characteristics, PCR Ct value, and blood biomarkers.

Interstitial lung abnormalities and interstitial lung diseases associated with cigarette smoking in a rural cohort undergoing surgical resection

Background

Cigarette smoking is a risk factor for interstitial lung abnormalities (ILAs) and interstitial lung diseases (ILDs). Investigation defining the relationships between ILAs/ILDs and clinical, radiographic, and pathologic findings in smokers have been incomplete. Employing a cohort undergoing surgical resection for lung nodules/masses, we (1) define the prevalence of ILAs/ILDs, (2) delineate their clinical, radiographic and pathologic predictors, and (3) determine their associations with mortality.

Methods

Patients undergoing resection of lung nodules/masses between 2017 and 2020 at a rural Appalachian, tertiary medical center were retrospectively investigated. Predictors for ILAs/ILDs and mortality were assessed using multivariate logistic regression analysis.

Results

In the total study cohort of 352 patients, radiographic ILAs and ILDs were observed in 35.2% and 17.6%, respectively. Among ILA patterns, subpleural reticular changes (14.8%), non-emphysematous cysts, centrilobular (CL) ground glass opacities (GGOs) (8% each), and mixed CL-GGO and subpleural reticular changes (7.4%) were common. ILD patterns included combined pulmonary fibrosis emphysema (CPFE) (3.1%), respiratory bronchiolitis (RB)-ILD (3.1%), organizing pneumonitis (2.8%) and unclassifiable (4.8%). The group with radiographic ILAs/ILDs had a significantly higher proportion of ever smokers (49% vs. 39.9%), pack years of smoking (44.57 ± 36.21 vs. 34.96 ± 26.22), clinical comorbidities of COPD (35% vs. 26.5%) and mildly reduced diffusion capacity (% predicated 66.29 ± 20.55 vs. 71.84 ± 23). Radiographic centrilobular and paraseptal emphysema (40% vs. 22.2% and 17.6% vs. 9.6%, respectively) and isolated traction bronchiectasis (10.2% vs. 4.2%) were associated with ILAs/ILDs. Pathological variables of emphysema (34.9% vs. 18.5%), any fibrosis (15.9% vs. 4.6%), peribronchiolar metaplasia (PBM, 8% vs. 1.1%), RB (10.3% vs. 2.5%), and anthracosis (21.6% vs. 14.5%) were associated with ILAs/ILDs. Histologic emphysema showed positive correlations with any fibrosis, RB, anthracosis and ≥ 30 pack year of smoking. The group with ILAs/ILDs had significantly higher mortality (9.1% vs. 2.2%, OR 4.13, [95% CI of 1.84–9.25]).

Conclusions

In a rural cohort undergoing surgical resection, radiographic subclinical ILAs/ILDs patterns were highly prevalent and associated with ever smoking and intensity of smoking. The presence of radiographic ILA/ILD patterns and isolated honeycomb changes were associated with increased mortality. Subclinical ILAs/ILDs and histologic fibrosis correlated with clinical COPD as well as radiographic and pathologic emphysema emphasizing the co-existence of these pulmonary injuries in a heavily smoking population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-01961-9.

Computed tomography on lung cancer screening is useful for adjuvant comorbidity diagnosis in developing countries

Purpose

The aim of this study was to analyse and quantify the prevalence of six comorbidities from lung cancer screening (LCS) on computed tomography (CT) scans of patients from developing countries.

Methods

For this retrospective study, low-dose CT scans (n=775) were examined from patients who underwent LCS in a tertiary hospital between 2016 and 2020. An age- and sex-matched control group was obtained for comparison (n=370). Using the software, coronary artery calcification (CAC), the skeletal muscle area, interstitial lung abnormalities, emphysema, osteoporosis and hepatic steatosis were accessed. Clinical characteristics of each participant were identified. A t-test and Chi-squared test were used to examine differences between these values. Interclass correlation coefficients (ICCs) and interobserver agreement (assessed by calculating kappa coefficients) were calculated to assess the correlation of measures interpreted by two observers. p-values <0.05 were considered significant.

Results

One or more comorbidities were identified in 86.6% of the patients and in 40% of the controls. The most prevalent comorbidity was osteoporosis, present in 44.2% of patients and in 24.8% of controls. New diagnoses of cardiovascular disease, emphysema and osteoporosis were made in 25%, 7% and 46% of cases, respectively. The kappa coefficient for CAC was 0.906 (p<0.001). ICCs for measures of liver, spleen and bone density were 0.88, 0.93 and 0.96, respectively (p<0.001).

Conclusions

CT data acquired during LCS led to the identification of previously undiagnosed comorbidities. The LCS is useful to facilitate comorbidity diagnosis in developing countries, providing opportunities for its prevention and treatment.

Lung cancer screening is useful to facilitate comorbidity diagnosis in developing countries, providing opportunities for its prevention and treatmenthttps://bit.ly/3KEdGuW

Restricted spirometry and cardiometabolic comorbidities: results from the international population based BOLD study

Background

Whether restricted spirometry, i.e. low Forced Vital Capacity (FVC), predicts chronic cardiometabolic disease is not definitely known. In this international population-based study, we assessed the relationship between restricted spirometry and cardiometabolic comorbidities.

Methods

A total of 23,623 subjects (47.5% males, 19.0% current smokers, age: 55.1 ± 10.8 years) from five continents (33 sites in 29 countries) participating in the Burden of Obstructive Lung Disease (BOLD) study were included. Restricted spirometry was defined as post-bronchodilator FVC < 5th percentile of reference values. Self-reports of physician-diagnosed cardiovascular disease (CVD; heart disease or stroke), hypertension, and diabetes were obtained through questionnaires.

Results

Overall 31.7% of participants had restricted spirometry. However, prevalence of restricted spirometry varied approximately ten-fold, and was lowest (8.5%) in Vancouver (Canada) and highest in Sri Lanka (81.3%). Crude odds ratios for the association with restricted spirometry were 1.60 (95% CI 1.37–1.86) for CVD, 1.53 (95% CI 1.40–1.66) for hypertension, and 1.98 (95% CI 1.71–2.29) for diabetes. After adjustment for age, sex, education, Body Mass Index (BMI) and smoking, the odds ratios were 1.54 (95% CI 1.33–1.79) for CVD, 1.50 (95% CI 1.39–1.63) for hypertension, and 1.86 (95% CI 1.59–2.17) for diabetes.

Conclusion

In this population-based, international, multi-site study, restricted spirometry associates with cardiometabolic diseases. The magnitude of these associations appears unattenuated when cardiometabolic risk factors are taken into account.

Detection and Early Referral of Patients With Interstitial Lung Abnormalities: An Expert Survey Initiative

BACKGROUND

Interstitial lung abnormalities (ILA) may represent undiagnosed early-stage or subclinical interstitial lung disease (ILD). ILA are often observed incidentally in patients who subsequently develop clinically overt ILD. There is limited information on consensus definitions for, and the appropriate evaluation of, ILA. Early recognition of patients with ILD remains challenging, yet critically important. Expert consensus could inform early recognition and referral.

RESEARCH QUESTION

Can consensus-based expert recommendations be identified to guide clinicians in the recognition, referral, and follow-up of patients with or at risk of developing early ILDs?

STUDY DESIGN AND METHODS

Pulmonologists and radiologists with expertise in ILD participated in two iterative rounds of surveys. The surveys aimed to establish consensus regarding ILA reporting, identification of patients with ILA, and identification of populations that might benefit from screening for ILD. Recommended referral criteria and follow-up processes were also addressed. Threshold for consensus was defined a priori as ≥ 75% agreement or disagreement.

RESULTS

Fifty-five experts were invited and 44 participated; consensus was reached on 39 of 85 questions. The following clinically important statements achieved consensus: honeycombing and traction bronchiectasis or bronchiolectasis indicate potentially progressive ILD; honeycombing detected during lung cancer screening should be reported as potentially significant (eg, with the Lung CT Screening Reporting and Data System "S-modifier" [Lung-RADS; which indicates clinically significant or potentially significant noncancer findings]), recommending referral to a pulmonologist in the radiology report; high-resolution CT imaging and full pulmonary function tests should be ordered if nondependent subpleural reticulation, traction bronchiectasis, honeycombing, centrilobular ground-glass nodules, or patchy ground-glass opacity are observed on CT imaging; patients with honeycombing or traction bronchiectasis should be referred to a pulmonologist irrespective of diffusion capacity values; and patients with systemic sclerosis should be screened with pulmonary function tests for early-stage ILD.

INTERPRETATION

Guidance was established for identifying clinically relevant ILA, subsequent referral, and follow-up. These results lay the foundation for developing practical guidance on managing patients with ILA.

Artificial Intelligence for Interstitial Lung Disease Analysis on Chest Computed Tomography: A Systematic Review

RATIONALE AND OBJECTIVES

High-resolution computed tomography (HRCT) is paramount in the assessment of interstitial lung disease (ILD). Yet, HRCT interpretation of ILDs may be hampered by inter- and intra-observer variability. Recently, artificial intelligence (AI) has revolutionized medical image analysis. This technology has the potential to advance patient care in ILD. We aimed to systematically evaluate the application of AI for the analysis of ILD in HRCT.

MATERIALS AND METHODS

We searched MEDLINE/PubMed databases for original publications of deep learning for ILD analysis on chest CT. The search included studies published up to March 1, 2021. The risk of bias evaluation included tailored Quality Assessment of Diagnostic Accuracy Studies and the modified Joanna Briggs Institute Critical Appraisal checklist.

RESULTS

Data was extracted from 19 retrospective studies. Deep learning techniques included detection, segmentation, and classification of ILD on HRCT. Most studies focused on the classification of ILD into different morphological patterns. Accuracies of 78%-91% were achieved. Two studies demonstrated near-expert performance for the diagnosis of idiopathic pulmonary fibrosis (IPF). The Quality Assessment of Diagnostic Accuracy Studies tool identified a high risk of bias in 15/19 (78.9%) of the studies.

CONCLUSION

AI has the potential to contribute to the radiologic diagnosis and classification of ILD. However, the accuracy performance is still not satisfactory, and research is limited by a small number of retrospective studies. Hence, the existing published data may not be sufficiently reliable. Only well-designed prospective controlled studies can accurately assess the value of existing AI tools for ILD evaluation.

Interstitial lung abnormalities: new insights between theory and clinical practice

Interstitial lung abnormalities (ILAs) represent radiologic abnormalities incidentally detected on chest computed tomography (CT) examination, potentially related to interstitial lung diseases (ILD). Numerous studies have demonstrated that ILAs are associated with increased risk of progression toward pulmonary fibrosis and mortality. Some radiological patterns have been proven to be at a higher risk of progression. In this setting, the role of radiologists in reporting these interstitial abnormalities is critical. This review aims to discuss the most recent advancements in understanding this radiological entity and the open issues that still prevent the translation from theory to practice, emphasizing the importance of ILA recognition and adequately reporting in clinical practice.

Increased regional ventilation as early imaging marker for future disease progression of interstitial lung disease: a feasibility study

OBJECTIVES

Idiopathic pulmonary fibrosis (IPF) is a disease with a poor prognosis and a highly variable course. Pathologically increased ventilation-accessible by functional CT-is discussed as a potential predecessor of lung fibrosis. The purpose of this feasibility study was to investigate whether increased regional ventilation at baseline CT and morphological changes in the follow-up CT suggestive for fibrosis indeed occur in spatial correspondence.

METHODS

In this retrospective study, CT scans were performed at two time points between September 2016 and November 2020. Baseline ventilation was divided into four categories ranging from low, normal to moderately, and severely increased (C1-C4). Correlation between baseline ventilation and volume and density change at follow-up was investigated in corresponding voxels. The significance of the difference of density and volume change per ventilation category was assessed using paired t-tests with a significance level of p ≤ 0.05. The analysis was performed separately for normal (NAA) and high attenuation areas (HAA).

RESULTS

The study group consisted of 41 patients (73 ± 10 years, 36 men). In both NAA and HAA, significant increases of density and loss of volume were seen in areas of severely increased ventilation (C4) at baseline compared to areas of normal ventilation (C2, p < 0.001). In HAA, morphological changes were more heterogeneous compared to NAA.

CONCLUSION

Functional CT assessing the extent and distribution of lung parenchyma with pathologically increased ventilation may serve as an imaging marker to prospectively identify lung parenchyma at risk for developing fibrosis.

KEY POINTS

• Voxelwise correlation of serial CT scans suggests spatial correspondence between increased ventilation at baseline and structural changes at follow-up. • Regional assessment of pathologically increased ventilation at baseline has the potential to prospectively identify tissue at risk for developing fibrosis. • Presence and extent of pathologically increased ventilation may serve as an early imaging marker of disease activity.

Interstitial lung abnormalities - current knowledge and future directions

Efforts to grasp the significance of radiologic changes similar to interstitial lung disease (ILD) in undiagnosed individuals have intensified in the recent decade. The term interstitial lung abnormalities (ILA) is an emerging definition of such changes, defined by visual examination of computed tomography scans. Substantial insights have been made in the origins and clinical consequences of these changes, as well as automated measures of early lung fibrosis, which will likely lead to increased recognition of early fibrotic lung changes among clinicians and researchers alike.

Interstitial lung abnormalities have an estimated prevalence of 7–10% in elderly populations. They correlate with many ILD risk factors, both epidemiologic and genetic. Additionally, histopathological similarities with IPF exist in those with ILA. While no established blood biomarker of ILA exists, several have been suggested. Distinct imaging patterns indicating advanced fibrosis correlate with worse clinical outcomes. ILA are also linked with adverse clinical outcomes such as increased mortality and risk of lung cancer.

Progression of ILA has been noted in a significant portion of those with ILA and is associated with many of the same features as ILD, including advanced fibrosis. Those with ILA progression are at risk of accelerated FVC decline and increased mortality. Radiologic changes resembling ILD have also been attained by automated measures. Such measures associate with some, but not all the same factors as ILA.

ILA and similar radiologic changes are in many ways analogous to ILD and likely represent a precursor of ILD in some cases. While warranting an evaluation for ILD, they are associated with poor clinical outcomes beyond possible ILD development and thus are by themselves a significant finding. Among the present objectives of this field are the stratification of patients with regards to progression and the discovery of biomarkers with predictive value for clinical outcomes.

Associations of D-Dimer with Computed Tomographic Lung Abnormalities, Serum Biomarkers of Lung Injury, and Forced Vital Capacity: MESA Lung Study

Rationale: The coagulation cascade may play a role in the pathogenesis of interstitial lung disease through increased production of thrombin and fibrin deposition. Whether circulating coagulation cascade factors are linked to lung inflammation and scarring among community-dwelling adults is unknown. Objectives: To test the hypothesis that higher baseline D-dimer concentrations are associated with markers of early lung injury and scarring. Methods: Using the MESA (Multi-Ethnic Study of Atherosclerosis) cohort (n = 6,814), we examined associations of baseline D-dimer concentrations with high attenuation areas from examination 1 (2000-2002; n = 6,184) and interstitial lung abnormalities from examination 5 computed tomographic (CT) scans (2010-2012; n = 2,227), and serum MMP-7 (matrix metalloproteinase-7) and SP-A (surfactant protein-A) from examination 1 (n = 1,098). We examined longitudinal change in forced vital capacity (FVC) from examinations 3-6 (2004-2018, n = 3,562). We used linear logistic regression and linear mixed models to examine associations and adjust for potential confounders. Results: The mean (standard deviation) age of the cohort was 62 (10) years, and the D-dimer concentration was 0.35 (0.69) ug/ml. For every 10% increase in D-dimer concentration, there was an increase in high attenuation area percentage of 0.27 (95% confidence interval (CI), 0.08-0.47) after adjustment for covariates. Associations were stronger among those older than 65 years (P values for interaction < 0.001). A 10% increase in D-dimer concentration was associated with an odds ratio of 1.05 for interstitial lung abnormalities (95% CI, 0.99-1.11). Higher D-dimer concentrations were associated with higher serum MMP-7 and a faster decline in FVC. D-dimer was not associated with SP-A. Conclusions: Higher D-dimer concentrations were associated with a greater burden of lung parenchymal abnormalities detected on CT scan, MMP-7, and FVC decline among community-dwelling adults.

Interstitial lung abnormalities: What do we know and how do we manage?

INTRODUCTION

Interstitial lung abnormalities (ILAs), which refer to mild or subtle nongravity-dependent interstitial changes, may be neglected by some clinicians due to many reasons, such as lack of diagnostic criteria for ILAs and absence of available treatments and surveillance strategies. However, without intervention, some ILAs may progress to interstitial lung disease (ILD). This review summarizes our current knowledge of this condition and ways of diagnosing it together with current management. We hope that this will lead to better recognition of ILAs.

AREAS COVERED

We reviewed the literature on PubMed between 2008 and 2020 focusing on prevalence, etiology, symptoms, diagnostic biomarkers, clinical associations, and management of ILAs.

EXPERT OPINION

Timely diagnosis with close monitoring of ILAs and appropriate intervention should be recognized as the management approach to ILAs. Research into ILAs should continue to improve its management.

Interstitial Lung Abnormalities: State of the Art

The clinical importance of interstitial lung abnormality (ILA) is increasingly recognized. In July 2020, the Fleischner Society published a position paper about ILA. The purposes of this article are to summarize the definition, existing evidence, clinical management, and unresolved issues for ILA from a radiologic standpoint and to provide a practical guide for radiologists. ILA is a common incidental finding at CT and is often progressive and associated with worsened clinical outcomes. The hazard ratios for mortality range from 1.3 to 2.7 in large cohorts. Risk factors for ILA include age, smoking status, other inhalational exposures, and genetic factors (eg, gene encoding mucin 5B variant). Radiologists should systematically record the presence, morphologic characteristics, distribution, and subcategories of ILA (ie, nonsubpleural, subpleural nonfibrotic, and subpleural fibrotic), as these are informative for predicting progression and mortality. Clinically significant interstitial lung disease should not be considered ILA. Individuals with ILA are triaged into higher- and lower-risk groups depending on their risk factors for progression, and systematic follow-up, including CT, should be considered for the higher-risk group. Artificial intelligence-based automated analysis for ILA may be helpful, but further validation and improvement are needed. Radiologists have a central role in clinical management and research on ILA.

The incremental value of computed tomography of COVID-19 pneumonia in predicting ICU admission

Triage is crucial for patient’s management and estimation of the required intensive care unit (ICU) beds is fundamental for health systems during the COVID-19 pandemic. We assessed whether chest computed tomography (CT) of COVID-19 pneumonia has an incremental role in predicting patient’s admission to ICU. We performed volumetric and texture analysis of the areas of the affected lung in CT of 115 outpatients with COVID-19 infection presenting to the emergency room with dyspnea and unresponsive hypoxyemia. Admission blood laboratory including lymphocyte count, serum lactate dehydrogenase, D-dimer and C-reactive protein and the ratio between the arterial partial pressure of oxygen and inspired oxygen were collected. By calculating the areas under the receiver-operating characteristic curves (AUC), we compared the performance of blood laboratory-arterial gas analyses features alone and combined with the CT features in two hybrid models (Hybrid radiological and Hybrid radiomics)for predicting ICU admission. Following a machine learning approach, 63 patients were allocated to the training and 52 to the validation set. Twenty-nine (25%) of patients were admitted to ICU. The Hybrid radiological model comprising the lung %consolidation performed significantly (p = 0.04) better in predicting ICU admission in the validation (AUC = 0.82; 95% confidence interval 0.73–0.97) set than the blood laboratory-arterial gas analyses features alone (AUC = 0.71; 95% confidence interval 0.56–0.86). A risk calculator for ICU admission was derived and is available at: https://github.com/cgplab/covidapp. The volume of the consolidated lung in CT of patients with COVID-19 pneumonia has a mild but significant incremental value in predicting ICU admission.

Early diagnosis of fibrotic interstitial lung disease: challenges and opportunities

Many patients with interstitial lung disease (ILD) develop pulmonary fibrosis, which can lead to reduced quality of life and early mortality. Patients with fibrotic ILD often have considerable diagnostic delay, and are exposed to unnecessary and costly diagnostic procedures, and ineffective and potentially harmful treatments. Non-specific and insidious presenting symptoms, along with scarce knowledge of fibrotic ILD among primary care physicians and non-ILD experts, are some of the main causes of diagnostic delay. Here, we outline and discuss the challenges facing both patients and physicians in making an early diagnosis of fibrotic ILD, and explore strategies to facilitate early identification of patients with fibrotic ILD, both in the general population and among individuals at highest risk of developing the disease. Finally, we discuss controversies and key uncertainties in screening programmes for fibrotic ILD. Timely identification and accurate diagnosis of patients with fibrotic ILD poses several substantial clinical challenges, but could potentially improve outcomes through early initiation of appropriate management.

Interstitial Lung Abnormalities Detected by CT in Asbestos-Exposed Subjects Are More Likely Associated to Age

Objective: the aim of this study was to evaluate the association between interstitial lung abnormalities, asbestos exposure and age in a population of retired workers previously occupationally exposed to asbestos. Methods: previously occupationally exposed former workers to asbestos eligible for a survey conducted between 2003 and 2005 in four regions of France, underwent chest CT examinations and pulmonary function testing. Industrial hygienists evaluated asbestos exposure and calculated for each subject a cumulative exposure index (CEI) to asbestos. Smoking status information was also collected in this second round of screening. Expert radiologists performed blinded independent double reading of chest CT-scans and classified interstitial lung abnormalities into: no abnormality, minor interstitial findings, interstitial findings inconsistent with UIP, possible or definite UIP. In addition, emphysema was assessed visually (none, minor: emphysema <25%, moderate: between 25 and 50% and severe: >50% of the lung). Logistic regression models adjusted for age and smoking were used to assess the relationship between interstitial lung abnormalities and occupational asbestos exposure. Results: the study population consisted of 2157 male subjects. Interstitial lung abnormalities were present in 365 (16.7%) and emphysema in 444 (20.4%). Significant positive association was found between definite or possible UIP pattern and age (OR adjusted =1.08 (95% CI: 1.02–1.13)). No association was found between interstitial abnormalities and CEI or the level of asbestos exposure. Conclusion: presence of interstitial abnormalities at HRCT was associated to aging but not to cumulative exposure index in this cohort of former workers previously occupationally exposed to asbestos.

Automated Diseased Lung Volume Percentage Calculation in Quantitative CT Evaluation of Chronic Obstructive Pulmonary Disease and Idiopathic Pulmonary Fibrosis

OBJECTIVE

Several software-based quantitative computed tomography (CT) analysis methods have been developed for assessing emphysema and interstitial lung disease. Although the texture classification method appeared to be more successful than the other methods, the software programs are not commercially available, to our knowledge. Therefore, this study aimed to investigate the usefulness of a commercially available software program for quantitative CT analyses.

METHODS

This prospective cohort study included 80 patients with chronic obstructive pulmonary disease (COPD) or idiopathic pulmonary fibrosis (IPF).

RESULTS

The percentage of low attenuation volume and high attenuation volume had high sensitivity and high specificity for detecting emphysema and pulmonary fibrosis, respectively. The percentage of diseased lung volume (DLV%) was significantly correlated with the lung diffusion capacity for carbon monoxide in all patients with COPD and IPF patients.

CONCLUSIONS

The quantitative CT analysis may improve the precision of the assessment of DLV%, which itself could be a useful tool in predicting lung diffusion capacity in patients with the clinical diagnosis of COPD or IPF.

Clinical Relevance and Management of "Pre-Interstitial Lung Disease"

Cellular level changes that lead to interstitial lung disease (ILD) may take years to become clinically apparent and have been termed preclinical ILD. Incidentally identified interstitial lung abnormalities (ILA) are increasingly being recognized on chest computed tomographic scans done as part of lung cancer screening and for other purposes. Many individuals found to have ILA will progress to clinically significant ILD. ILA are independently associated with greater risk of death, lung function decline, and incident lung cancer. Current management recommendations focus on identifying individuals with ILA at high risk of progression, through a combination of clinical and radiological features.

Automated CT Lung Density Analysis of Viral Pneumonia and Healthy Lungs Using Deep Learning-Based Segmentation, Histograms and HU Thresholds

CT patterns of viral pneumonia are usually only qualitatively described in radiology reports. Artificial intelligence enables automated and reliable segmentation of lungs with chest CT. Based on this, the purpose of this study was to derive meaningful imaging biomarkers reflecting CT patterns of viral pneumonia and assess their potential to discriminate between healthy lungs and lungs with viral pneumonia. This study used non-enhanced and CT pulmonary angiograms (CTPAs) of healthy lungs and viral pneumonia (SARS-CoV-2, influenza A/B) identified by radiology reports and RT-PCR results. After deep learning segmentation of the lungs, histogram-based and threshold-based analyses of lung attenuation were performed and compared. The derived imaging biomarkers were correlated with parameters of clinical and biochemical severity (modified WHO severity scale; c-reactive protein). For non-enhanced CTs (n = 526), all imaging biomarkers significantly differed between healthy lungs and lungs with viral pneumonia (all p < 0.001), a finding that was not reproduced for CTPAs (n = 504). Standard deviation (histogram-derived) and relative high attenuation area [600-0 HU] (HU-thresholding) differed most. The strongest correlation with disease severity was found for absolute high attenuation area [600-0 HU] (r = 0.56, 95% CI = 0.46-0.64). Deep-learning segmentation-based histogram and HU threshold analysis could be deployed in chest CT evaluation for the differentiating of healthy lungs from AP lungs.