Identification of early interstitial lung disease in smokers from the COPDGene Study

Interstitial Lung Abnormality: Narrative Review of the Approach to Diagnosis and Management

TOPIC IMPORTANCE

As interstitial lung abnormalities (ILAs) are increasingly recognized on imaging and in clinical practice, identification and appropriate management are critical. We propose an algorithmic approach to the identification and management of patients with ILAs.

REVIEW FINDINGS

The radiologist initially identifies chest CT scan findings suggestive of an ILA pattern and excludes findings that are not consistent with ILAs. The next step is to confirm that these findings occupy > 5% of a nondependent lung zone. At this point, the radiologic pattern of ILA is identified. These findings are classified as non-subpleural, subpleural nonfibrotic, and subpleural fibrotic. It is then incumbent on the clinician to ascertain if the patient has symptoms and/or abnormal pulmonary physiology that may be attributable to these radiologic changes. Based on the patient's symptoms, physiological assessment, and risk factors for interstitial lung disease (ILD), we recommend classifying patients as having ILA, at high risk for developing ILD, probable ILD, or ILD. In patients identified as having ILA, a multidisciplinary discussion should evaluate features that indicate an increased risk of progression. If these features are present, serial monitoring is recommended to be proactive. If the patient does not have imaging or clinical features that indicate an increased risk of progression, then monitoring is recommended to be reactive. If ILD is subsequently diagnosed, the management is disease specific.

SUMMARY

We anticipate this algorithmic approach will aid clinicians in interpreting the radiologic pattern described as ILA within the clinical context of their patients.

Impact of Sex, Serostatus, and Smoking on Risk for Rheumatoid Arthritis-Associated Interstitial Lung Disease Subtypes

OBJECTIVE

Rheumatoid arthritis-associated interstitial lung disease (RA-ILD) includes multiple subtypes with varying histopathology, prognosis, and potential treatments. Limited research has investigated risk factors for different RA-ILD subtypes. Therefore, we examined demographic, serologic, and lifestyle associations with RA-ILD subtypes.

METHODS

We systematically identified RA-ILD cases and RA controls without ILD (RA-noILD) in the Brigham RA Sequential Study and Mass General Brigham Biobank RA cohort. We determined RA-ILD subtype (usual interstitial pneumonia [UIP], nonspecific interstitial pneumonia [NSIP], and other/indeterminate) through chest high-resolution computed tomography imaging pattern. We investigated associations of demographic, lifestyle, and serologic factors with major RA-ILD subtypes using multivariable logistic regression.

RESULTS

Among 3,328 patients with RA, we identified 208 RA-ILD cases and 547 RA-noILD controls. RA-UIP was associated with older age (odds ratio [OR] 1.03 per year, 95% confidence interval [95% CI] 1.01-1.05), male sex (OR 2.15, 95% CI 1.33-3.48), and seropositivity (OR 2.08, 95% CI 1.24-3.48), whereas RA-NSIP was significantly associated only with seropositive status (OR 3.21, 95% CI 1.36-7.56). Nonfibrotic ILDs were significantly associated with smoking (OR 2.81, 95% CI 1.52-5.21). Having three RA-ILD risk factors (male, seropositive, smoking) had an OR of 6.89 (95% CI 2.41-19.7) for RA-UIP compared with having no RA-ILD risk factors.

CONCLUSION

Older age, seropositivity, and male sex were strongly associated with RA-UIP, whereas RA-related autoantibodies were associated with RA-NSIP. These findings suggest RA-ILD sex differences may be driven by RA-UIP and emphasize the importance of further studies to clarify RA-ILD heterogeneity and optimize screening and treatment approaches.

Automated Interstitial Lung Abnormality Probability Prediction at CT: A Stepwise Machine Learning Approach in the Boston Lung Cancer Study

Background It is increasingly recognized that interstitial lung abnormalities (ILAs) detected at CT have potential clinical implications, but automated identification of ILAs has not yet been fully established. Purpose To develop and test automated ILA probability prediction models using machine learning techniques on CT images. Materials and Methods This secondary analysis of a retrospective study included CT scans from patients in the Boston Lung Cancer Study collected between February 2004 and June 2017. Visual assessment of ILAs by two radiologists and a pulmonologist served as the ground truth. Automated ILA probability prediction models were developed that used a stepwise approach involving section inference and case inference models. The section inference model produced an ILA probability for each CT section, and the case inference model integrated these probabilities to generate the case-level ILA probability. For indeterminate sections and cases, both two- and three-label methods were evaluated. For the case inference model, we tested three machine learning classifiers (support vector machine [SVM], random forest [RF], and convolutional neural network [CNN]). Receiver operating characteristic analysis was performed to calculate the area under the receiver operating characteristic curve (AUC). Results A total of 1382 CT scans (mean patient age, 67 years ± 11 [SD]; 759 women) were included. Of the 1382 CT scans, 104 (8%) were assessed as having ILA, 492 (36%) as indeterminate for ILA, and 786 (57%) as without ILA according to ground-truth labeling. The cohort was divided into a training set (n = 96; ILA, n = 48), a validation set (n = 24; ILA, n = 12), and a test set (n = 1262; ILA, n = 44). Among the models evaluated (two- and three-label section inference models; two- and three-label SVM, RF, and CNN case inference models), the model using the three-label method in the section inference model and the two-label method and RF in the case inference model achieved the highest AUC, at 0.87. Conclusion The model demonstrated substantial performance in estimating ILA probability, indicating its potential utility in clinical settings. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Zagurovskaya in this issue.

Forced vital capacity trajectories and risk of lung transplant and ILD-related mortality among patients with rheumatoid arthritis-associated interstitial lung disease

We aimed to determine the prevalence and outcomes for forced vital capacity percent predicted (FVCpp) decline among patients with rheumatoid arthritis-associated interstitial lung disease (RA-ILD). We identified patients with RA-ILD in the Mass General Brigham Healthcare system. RA-ILD diagnosis was determined by review of high-resolution computed tomography (HRCT) imaging by up to three thoracic radiologists. We abstracted FVCpp measurements, covariates, lung transplant, and ILD-related death from the medical record. We employed a relative FVCpp decline cutoff of > 10% within 24 months. We also used a group-based trajectory model to obtain patterns of change from RA-ILD diagnosis. We then assessed for associations of each FVC decline definition with risk of lung transplant or ILD-related death using multivariable logistic regression. We analyzed 172 patients with RA-ILD with a median of 6 FVCpp measurements per patient over 6.5 years of follow-up (mean age 62.2 years, 36% male). There were seven (4%) lung transplants and 44 (26%) ILD-related deaths. Ninety-eight (57%) patients had relative decline of FVCpp by > 10% in 24 months. We identified three trajectory groups of FVCpp change: rapidly declining (n = 24/168 [14%]), slowly declining (n = 90/168 [54%]), and stable/improving (n = 54/168 [32%]). The rapidly declining group and FVCpp > 10% had adjusted odds ratios (aOR) for lung transplant/ILD-related death of 19.2 (95%CI 4.9 to 75.5) and 2.8 (95%CI 1.3 to 6.1) respectively. Over half of patients with RA-ILD had declining FVCpp. The different trajectory patterns demonstrate the importance of FVC monitoring for identifying patients at the highest risk of poor outcomes. Key Points • Over half of patients with RA-ILD had declining FVCpp over a median of 6.5 years of follow-up. • The rapidly declining FVCpp trajectory group had stronger associations with lung transplant and ILD-related death compared to those with FVCpp decline by > 10%. • Clinicians can employ FVC monitoring to proactively treat patients who are at risk of poor outcomes.

Association between interstitial lung abnormality and mortality in patients with esophageal cancer

PURPOSE

To investigate the relationship between interstitial lung abnormalities (ILAs) and mortality in patients with esophageal cancer and the cause of mortality.

MATERIALS AND METHODS

This retrospective study investigated patients with esophageal cancer from January 2011 to December 2015. ILAs were visually scored on baseline CT using a 3-point scale (0 = non-ILA, 1 = indeterminate for ILA, and 2 = ILA). ILAs were classified into subcategories of non-subpleural, subpleural non-fibrotic, and subpleural fibrotic. Five-year overall survival (OS) was compared between patients with and without ILAs using the multivariable Cox proportional hazards model. Subgroup analyses were performed based on cancer stage and ILA subcategories. The prevalences of treatment complications and death due to esophageal cancer and pneumonia/respiratory failure were analyzed using Fisher's exact test.

RESULTS

A total of 478 patients with esophageal cancer (age, 66.8 years ± 8.6 [standard deviation]; 64 women) were evaluated in this study. Among them, 267 patients showed no ILAs, 125 patients were indeterminate for ILAs, and 86 patients showed ILAs. ILAs were a significant factor for shorter OS (hazard ratio [HR] = 1.68, 95% confidence interval [CI] 1.10-2.55, P = 0.016) in the multivariable Cox proportional hazards model adjusting for age, sex, smoking history, clinical stage, and histology. On subgroup analysis using patients with clinical stage IVB, the presence of ILAs was a significant factor (HR = 3.78, 95% CI 1.67-8.54, P = 0.001). Subpleural fibrotic ILAs were significantly associated with shorter OS (HR = 2.22, 95% CI 1.25-3.93, P = 0.006). There was no significant difference in treatment complications. Patients with ILAs showed a higher prevalence of death due to pneumonia/respiratory failure than those without ILAs (non-ILA, 2/95 [2%]; ILA, 5/39 [13%]; P = 0.022). The prevalence of death due to esophageal cancer was similar in patients with and without ILA (non-ILA, 82/95 [86%]; ILA 32/39 [82%]; P = 0.596).

CONCLUSION

ILAs were significantly associated with shorter survival in patients with esophageal cancer.

[Interstitial lung abnormalities : What the radiologist needs to know]

Interstitial lung abnormalities (ILA) are incidental findings on computed tomography (CT), particularly in elderly patients and smokers. They describe mild interstitial abnormalities that can be progressive and turn into overt interstitial lung disease (ILD). In recent years, ILA have increasingly come into focus because several large cohort studies have shown poorer clinical outcomes and increased mortality for patients with ILA compared to those without ILA. The radiological classification into nonsubpleural, subpleural nonfibrotic and subpleural fibrotic as well as the assessment over time can-together with clinical risk factors-help estimate clinical outcome. Clinical management of patients with ILA includes exclusion of ILD and risk-adapted control intervals, especially in the presence of risk factors.

COPD Subtypes Are Differentially Associated With Cardiovascular Events and COPD Exacerbations

BACKGROUND

The coronary artery calcium score (CACS) and ratio of the pulmonary artery to aorta diameters (PA:A ratio) measured from chest CT scans have been established as predictors of cardiovascular events and COPD exacerbations, respectively. However, little is known about the reciprocal relationship between these predictors and outcomes. Furthermore, the prognostic implications of COPD subtypes on clinical outcomes remain insufficiently characterized.

RESEARCH QUESTION

How can these two chest CT scan-derived parameters predict subsequent cardiovascular events and COPD exacerbations in different COPD subtypes?

STUDY DESIGN AND METHODS

Using COPDGene study data, we assessed prospective cardiovascular disease (CVD) and COPD exacerbation risk in patients with COPD (Global Initiative for Chronic Obstructive Lung Disease spirometric grades 2-4), focusing on CACS and PA:A ratio at study enrollment, with logistic regression models. These outcomes were analyzed in three COPD subtypes: 1,042 patients with non-emphysema-predominant disease (NEPD) (low attenuation area at -950 Hounsfield units [LAA-950] < 5%), 1,324 patients with emphysema-predominant disease (EPD) (LAA-950 ≥ 10%), and 465 patients with intermediate emphysema disease (5% ≤ LAA-950 < 10%).

RESULTS

Our study indicated significantly higher overall risk for cardiovascular events in patients with higher CACS (≥ median; OR, 1.61; 95% CI, 1.30-2.00) and increased COPD exacerbations in those with higher PA:A ratios (≥ 1; OR, 1.80; 95% CI, 1.46-2.23). Notably, patients with NEPD showed a stronger association between these indicators and clinical events than those with EPD (with CACS/CVD, NEPD vs EPD: OR, 2.02 vs 1.41; with PA:A ratio/COPD exacerbation, NEPD vs EPD: OR, 2.50 vs 1.65); the difference in ORs between COPD subtypes was statistically significant for CACS/CVD.

INTERPRETATION

Two chest CT scan parameters, CACS and PA:A ratio, hold distinct predictive values for cardiovascular events and COPD exacerbations that are influenced by specific COPD subtypes.

TRIAL REGISTRATION

ClinicalTrials.gov; No.: NCT00608764; URL: www.

CLINICALTRIALS

gov.

Prevalence and progression rate of interstitial lung abnormalities detected on thoracic CT: a systematic review and meta-analysis

OBJECTIVES

To estimate the pooled prevalence and progression rate of ILAs and identify the risk factors for radiological progression.

MATERIALS AND METHODS

An EMBASE and PubMed search was undertaken, identifying all studies meeting the inclusion criteria performed before May 10, 2023. Random effect models were used to estimate pooled prevalence, ILA progression rates, and odds ratio for radiological progression based on radiological subtype. Subgroup analyses were performed to compare the general and high-risk populations for lung cancer. The quality of the included studies was evaluated using the risk of bias assessment tool for non-randomized studies.

RESULTS

We analyzed 19 studies (241,541 patients) and 10 studies (1317 patients) for the pooled prevalence and progression rate of ILA, respectively. The pooled ILA prevalence was 9.7% (95% CI, 6.1-13.9%). The pooled prevalence was 6.8% (95% CI, 3.1-11.6%) and 7.1% (95% CI, 2.2-14.4%) in the general (six studies) and high-risk population for lung cancer (six studies), respectively. The pooled progression rate was 47.1% (95% CI, 29.1-65.5%). The pooled progression rate was 64.2% (95% CI, 45.0-81.2%, five studies) and 31.0% (95% CI, 8.2-60.5%, five studies) for longer (≥ 4.5 years) and shorter follow-up periods (< 4.5 years), respectively (p = 0.009). Fibrotic ILAs were significantly associated with a higher progression probability (combined OR, 5.55; 95% CI, 1.95-15.82).

CONCLUSIONS

The prevalence of ILAs was approximately 9.7%. Approximately half of the patients exhibited radiological progression, with the rate increasing over a longer follow-up period. Fibrotic ILA was a significant risk factor for radiological progression.

CLINICAL RELEVANCE STATEMENT

The prevalence of interstitial lung abnormalities (ILAs) is approximately 9.7%, with about half exhibiting progression; a longer follow-up duration and fibrotic ILAs are associated with a higher progression rate.

KEY POINTS

ILAs are increasingly recognized as important, but few population data are available. ILAs exhibited a pooled prevalence of 9.7% with a progression rate of 47.1%. Fibrotic ILAs were associated with increased progression likelihood.

Deleterious impact of trivial to severe interstitial pneumonia and emphysema on mortality and acute exacerbation of interstitial pneumonia in patients with lung cancer: a retrospective cohort study

BACKGROUND

Interstitial pneumonia and emphysema may complicate patients with lung cancer. However, clinical significance of trivial and mild pulmonary abnormalities remains unclear. In this study, we aimed to investigate whether trivial and mild interstitial pneumonia and emphysema, in addition to their advanced forms, impact the prognosis and lead to acute exacerbation of interstitial pneumonia (AEIP) in patients with lung cancer.

METHODS

This retrospective cohort study was conducted at a tertiary hospital and included patients with lung cancer. Computed tomography images were evaluated using the interstitial lung abnormality (ILA) score for interstitial pneumonia, which included no ILA, equivocal ILA, ILA, interstitial lung disease (ILD), and the Goddard score for emphysema. Cox analyses were performed using the ILA and Goddard scores as the main explanatory variables, adjusting for multiple covariates.

RESULTS

Among 1,507 patients with lung cancer, 1,033 had no ILA, 160 had equivocal ILA, 174 had ILA, and 140 had ILD. In total, 474 patients (31.5%) exhibited interstitial pneumonia and 638 (42.3%) showed emphysema. The log-rank trend test showed that survival probability was significantly better in patients with no ILA, followed by those with equivocal ILA, ILA, and ILD (P < 0.001). After adjustment, the ILA and Goddard scores remained significant variables for increased hazard ratios (HR) for mortality: no ILA (HR, 1.00: reference), equivocal ILA (HR, 1.31; 95% confidence interval [CI], 1.18-1.46; P < 0.001), ILA (HR, 1.71; 95% CI, 1.39-2.12; P < 0.001), ILD (HR, 2.24; 95% CI, 1.63-3.09; P < 0.001), and Goddard score (HR, 1.03; 95% CI, 1.01-1.06; P < 0.010). Moreover, both scores were associated with increased cause-specific HRs for AEIP.

CONCLUSION

Our results revealed that approximately one-third of patients with lung cancer had interstitial pneumonia when incorporating trivial and mild cases. Because interstitial pneumonia and emphysema, ranging from trivial to severe, significantly impact mortality and AEIP in patients with lung cancer, we should identify even trivial and mild cases of these pulmonary abnormalities among patients with lung cancer in addition to the advanced ones.

Chronic Obstructive Pulmonary Disease Exacerbations Increase the Risk of Subsequent Cardiovascular Events: A Longitudinal Analysis of the COPDGene Study

BACKGROUND

Cardiovascular disease (CVD) is the most important comorbidity in patients with chronic obstructive pulmonary disease (COPD). COPD exacerbations not only contribute to COPD progression but may also elevate the risk of CVD. This study aimed to determine whether COPD exacerbations increase the risk of subsequent CVD events using up to 15 years of prospective longitudinal follow-up data from the COPDGene (Genetic Epidemiology of Chronic Obstructive Pulmonary Disease) study.

METHODS AND RESULTS

The COPDGene study is a large, multicenter, longitudinal investigation of COPD, including subjects at enrollment aged 45 to 80 years with a minimum of 10 pack-years of smoking history. Cox proportional hazards models and Kaplan-Meier survival curves were used to assess the risk of a composite end point of CVD based on the COPD exacerbation rate. Frequent exacerbators exhibited a higher cumulative incidence of composite CVD end points than infrequent exacerbators, irrespective of the presence of CVD at baseline. After adjusting for covariates, frequent exacerbators still maintained higher hazard ratios (HRs) than the infrequent exacerbator group (without CVD: HR, 1.81 [95% CI, 1.47-2.22]; with CVD: HR, 1.92 [95% CI, 1.51-2.44]). This observation remained consistently significant in moderate to severe COPD subjects and the preserved ratio impaired spirometry population. In the mild COPD population, frequent exacerbators showed a trend toward more CVD events.

CONCLUSIONS

COPD exacerbations are associated with an increased risk of subsequent cardiovascular events in subjects with and without preexisting CVD. Patients with COPD experiencing frequent exacerbations may necessitate careful monitoring and additional management for subsequent potential CVD.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT00608764.

Interstitial Lung Abnormalities

Interstitial lung abnormalities (ILA) is a radiographic term, which has recently undergone clarification of definition with creation of 3 subtypes. ILA is defined as incidental identification of computed tomography abnormalities in a patient who is not suspected of having an interstitial lung disease (ILD). A subset of ILA may progress to clinically significant ILD and is associated with morbidities not related to progression such as an increased incidence of sepsis-related acute respiratory distress syndrome (ARDS). ILA has been associated with an increased incidence of treatment-related complications in patients with lung cancer. Information on corresponding histology is limited; knowledge gaps exist concerning optimal patient management.

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.

Prognostic impact of interstitial lung abnormalities in lung cancer: a systematic review and meta-analysis

Background

Newly identified as a radiological concept, interstitial lung abnormalities (ILA) is emerging as a prognostic factor for lung cancer. Yet, debates persist regarding the prognostic significance of ILA in lung cancer. Our inaugural meta-analysis aimed to investigate the correlation between ILA and lung cancer outcomes, offering additional insights for clinicians in predicting patient prognosis.

Methods

Articles meeting the criteria were found through PubMed, the Cochrane Library, EMBASE, and Web of Science by February 29, 2024. The outcomes evaluated were the survival rates such as overall survival (OS), disease-free survival (DFS), progression-free survival (PFS), and cancer-specific survival (CSS).

Results

A total of 12 articles with 4416 patients were included in this meta-analysis. The pooled results showed that lung cancer patients with interstitial lung abnormalities had an inferior OS (n=11; HR=2.22; 95% CI=1.68-2.95; P<0.001; I2 = 72.0%; Ph<0.001), PFS (n=3; HR=1.59; 95% CI=1.08-2.32; P=0.017; I2 = 0%; Ph=0.772), and CSS (n=2; HR=4.00; 95% CI=1.94-8.25; P<0.001; I2 = 0%; Ph=0.594) than those without, however, the ILA was not significantly associated with the DFS (n=2; HR=2.07; 95% CI=0.94-7.02; P=0.066; I2 = 90.4%; Ph=0.001). Moreover, lung cancer patients with ILA were significantly correlated with male (OR=2.43; 95% CI=1.48-3.98; P<0.001), smoking history (OR=2.11; 95% CI=1.37-3.25; P<0.001), advanced age (OR=2.50; 95% CI=1.56-4.03; P<0.001), squamous carcinoma (OR=0.42; 95% CI=0.24-0.71; P=0.01), and EGFR mutation (OR=0.50; 95% CI=0.32-0.78; P=0.002). The correlation between ILA and race, stage, ALK, however, was not significant.

Conclusion

ILA was a availability factors of prognosis in patients with lung cancers. These findings highlight the importance of early pulmonary fibrosis, namely ILA for prognosis in patients with lung cancer, and provide a partial rationale for future clinical work.

Clinical outcomes of interstitial lung abnormalities: a systematic review and meta-analysis

Interstitial lung abnormalities (ILA), incidental findings on computed tomography scans, have raised concerns due to their association with worse clinical outcomes. Our meta-analysis, which included studies up to April 2023 from PubMed/MEDLINE, Embase, and Cochrane Library, aimed to clarify the impact of ILA on mortality, lung cancer development, and complications from lung cancer treatments. Risk ratios (RR) with 95% confidence intervals (CI) were calculated for outcomes. Analyzing 10 studies on ILA prognosis and 9 on cancer treatment complications, we found that ILA significantly increases the risk of overall mortality (RR 2.62, 95% CI 1.94-3.54; I2 = 90%) and lung cancer development (RR 3.85, 95% CI 2.64-5.62; I2 = 22%). Additionally, cancer patients with ILA had higher risks of grade 2 radiation pneumonitis (RR 2.28, 95% CI 1.71-3.03; I2 = 0%) and immune checkpoint inhibitor-related interstitial lung disease (RR 3.05, 95% CI 1.37-6.77; I2 = 83%) compared with those without ILA. In conclusion, ILA significantly associates with increased mortality, lung cancer risk, and cancer treatment-related complications, highlighting the necessity for vigilant patient management and monitoring.

A Plant-Centered Diet is Inversely Associated With Radiographic Emphysema: Findings from the CARDIA Lung Study

Background

Chronic obstructive pulmonary disease (COPD) is a significant public health concern and intercepting the development of emphysema is vital for COPD prevention. Smokers are a high-risk population for emphysema with limited prevention strategies. We aimed to determine if adherence to a nutritionally rich, plant-centered diet among young ever-smokers is associated with reduced risk of future radiographic emphysema.

Methods

We studied participants from the Coronary Artery Risk Development in Young Adults (CARDIA) Lung Prospective Cohort Study who were 18-30 years old at enrollment and followed for 30 years. We analyzed 1706 adults who reported current or former smoking by year 20. Repeated measures of diet history were used to calculate A Priori Diet Quality Scores (APDQSs), and categorized into quintiles, with higher quintiles representing higher nutritionally rich plant-centered food intake. Emphysema was assessed at year 25 (n=1351) by computed tomography (CT). Critical covariates were selected, acknowledging potential residual confounding.

Results

Emphysema was observed in 13.0% of the cohort, with a mean age of 50.4 ± 3.5 years. The prevalence of emphysema was 4.5% in the highest APDQS quintile (nutritionally rich), compared with 25.4% in the lowest quintile. After adjustment for multiple covariates, including smoking, greater adherence to a plant-centered diet was inversely associated with emphysema (highest versus lowest quintile odds ratio: 0.44, 95% CI 0.19-0.99, ptrend=0.008).

Conclusion

Longitudinal adherence to a nutritionally rich, plant-centered diet was associated with a decreased risk of emphysema development in middle adulthood, warranting further examination of diet as a strategy for emphysema prevention in a high-risk smoking population.

Utility of peripheral protein biomarkers for the prediction of incident interstitial features: a multicentre retrospective cohort study

INTRODUCTION/RATIONALE

Protein biomarkers may help enable the prediction of incident interstitial features on chest CT.

METHODS

We identified which protein biomarkers in a cohort of smokers (COPDGene) differed between those with and without objectively measured interstitial features at baseline using a univariate screen (t-test false discovery rate, FDR p<0.001), and which of those were associated with interstitial features longitudinally (multivariable mixed effects model FDR p<0.05). To predict incident interstitial features, we trained four random forest classifiers in a two-thirds random subset of COPDGene: (1) imaging and demographic information, (2) univariate screen biomarkers, (3) multivariable confirmation biomarkers and (4) multivariable confirmation biomarkers available in a separate testing cohort (Pittsburgh Lung Screening Study (PLuSS)). We evaluated classifier performance in the remaining one-third of COPDGene, and, for the final model, also in PLuSS.

RESULTS

In COPDGene, 1305 biomarkers were available and 20 differed between those with and without interstitial features at baseline. Of these, 11 were associated with feature progression over a mean of 5.5 years of follow-up, and of these 4 were available in PLuSS, (angiopoietin-2, matrix metalloproteinase 7, macrophage inflammatory protein 1 alpha) over a mean of 8.8 years of follow-up. The area under the curve (AUC) of classifiers using demographics and imaging features in COPDGene and PLuSS were 0.69 and 0.59, respectively. In COPDGene, the AUC of the univariate screen classifier was 0.78 and of the multivariable confirmation classifier was 0.76. The AUC of the final classifier in COPDGene was 0.75 and in PLuSS was 0.76. The outcome for all of the models was the development of incident interstitial features.

CONCLUSIONS

Multiple novel and previously identified proteomic biomarkers are associated with interstitial features on chest CT and may enable the prediction of incident interstitial diseases such as idiopathic pulmonary fibrosis.

Interstitial lung abnormality evaluated by an automated quantification system: prevalence and progression rate

BACKGROUND

Despite the importance of recognizing interstitial lung abnormalities, screening methods using computer-based quantitative analysis are not well developed, and studies on the subject with an Asian population are rare. We aimed to identify the prevalence and progression rate of interstitial lung abnormality evaluated by an automated quantification system in the Korean population.

METHODS

A total of 2,890 healthy participants in a health screening program (mean age: 49 years, men: 79.5%) with serial chest computed tomography images obtained at least 5 years apart were included. Quantitative lung fibrosis scores were measured on the chest images by an automated quantification system. Interstitial lung abnormalities were defined as a score ≥ 3, and progression as any score increased above baseline.

RESULTS

Interstitial lung abnormalities were identified in 251 participants (8.6%), who were older and had a higher body mass index. The prevalence increased with age. Quantification of the follow-up images (median interval: 6.5 years) showed that 23.5% (59/251) of participants initially diagnosed with interstitial lung abnormality exhibited progression, and 11% had developed abnormalities (290/2639). Older age, higher body mass index, and higher erythrocyte sedimentation rate were independent risk factors for progression or development. The interstitial lung abnormality group had worse survival on follow-up (5-year mortality: 3.4% vs. 1.5%; P = 0.010).

CONCLUSIONS

Interstitial lung abnormality could be identified in one-tenth of the participants, and a quarter of them showed progression. Older age, higher body mass index and higher erythrocyte sedimentation rate increased the risk of development or progression of interstitial lung abnormality.

Pre-existing Interstitial Lung Abnormalities and Immune Checkpoint Inhibitor-Related Pneumonitis in Solid Tumors: A Retrospective Analysis

BACKGROUND

Immune checkpoint inhibitors (ICIs) have demonstrated efficacy over previous cytotoxic chemotherapies in clinical trials among various tumors. Despite their favorable outcomes, they are associated with a unique set of toxicities termed as immune-related adverse events (irAEs). Among the toxicities, ICI-related pneumonitis has poor outcomes with little understanding of its risk factors. This retrospective study aimed to investigate whether pre-existing interstitial lung abnormality (ILA) is a potential risk factor for ICI-related pneumonitis.

MATERIALS AND METHODS

Patients with non-small cell lung cancer, malignant melanoma, renal cell carcinoma, and gastric cancer, who was administered either nivolumab, pembrolizumab, or atezolizumab between September 2014 and January 2019 were retrospectively reviewed. Information on baseline characteristics, computed tomography findings before administration of ICIs, clinical outcomes, and irAEs were collected from their medical records. Pre-existing ILA was categorized based on previous studies.

RESULTS

Two-hundred-nine patients with a median age of 68 years were included and 23 (11.0%) developed ICI-related pneumonitis. While smoking history and ICI agents were associated with ICI-related pneumonitis (P = .005 and .044, respectively), the categories of ILA were not associated with ICI-related pneumonitis (P = .428). None of the features of lung abnormalities were also associated with ICI-related pneumonitis. Multivariate logistic analysis indicated that smoking history was the only significant predictor of ICI-related pneumonitis (P = .028).

CONCLUSION

This retrospective study did not demonstrate statistically significant association between pre-existing ILA and ICI-related pneumonitis, nor an association between radiologic features of ILA and ICI-related pneumonitis. Smoking history was independently associated with ICI-related pneumonitis. Further research is warranted for further understanding of the risk factors of ICI-related pneumonitis.

Practice patterns in reporting interstitial lung abnormality at a tertiary academic medical center

PURPOSE

Interstitial lung abnormality (ILA) is a common finding on chest CTs and is associated with higher all-cause mortality. The 2020 Fleischner Society position paper standardized the terminology and definition of ILA. Despite these published guidelines, the extent to which radiologists use this term is unknown. We evaluated practice patterns for identification of ILAs among radiologists at a tertiary academic medical center.

METHODS

In this retrospective review, we identified 157 radiology reports between January 1, 2010 through December 31, 2021 containing the phrase "interstitial lung abnormality" or "interstitial abnormality". After exclusions, 125 CT scans were reviewed by thoracic-trained radiologists using the sequential reading method.

RESULTS

Seventy-seven (62%) patients were found to have ILA (69% subpleural fibrotic, 19% subpleural non-fibrotic, and 6% non-subpleural), nine (7%) were equivocal for ILA and 39 (31%) had no ILA. The term ILA was used exclusively by thoracic-trained radiologists except for two cases. Use of the term ILA has rapidly increased since the position paper publication (none from 2010-2017, one case in 2018, 20 cases in 2019, 41 cases in 2020, and 73 cases in 2021), and cases were typically very mild (1-25% of the lung).

CONCLUSION

While there has been increased use of the term ILA among thoracic-trained radiologists, non-thoracic radiologists have essentially not begun to use the term. Almost one-third of cases labeled ILA on clinical reads were re-classified as not having ILA on research reads.

Radiologic Progression of Interstitial Lung Abnormalities following Surgical Resection in Patients with Lung Cancer

In this study, we aimed to assess the prevalence of interstitial lung abnormalities (ILAs) and investigate the rates and risk factors associated with radiologic ILA progression among patients with lung cancer following surgical resection. Patients who underwent surgical resection for lung cancer at our institution from January 2015 to December 2020 were retrospectively evaluated and grouped according to their ILA status as having no ILAs, equivocal ILAs, or ILAs. Progression was determined by simultaneously reviewing the baseline and corresponding follow-up computed tomography (CT) scans. Among 346 patients (median age: 67 (interquartile range: 60-74) years, 204 (59.0%) men), 22 (6.4%) had equivocal ILAs, and 33 (9.5%) had ILAs detected upon baseline CT. Notably, six patients (6/291; 2.1%) without ILAs upon baseline CT later developed ILAs, and 50% (11/22) of those with equivocal ILAs exhibited progression. Furthermore, 75.8% (25/33) of patients with ILAs upon baseline CT exhibited ILA progression (76.9% and 71.4% with fibrotic and non-fibrotic ILAs, respectively). Multivariate analysis revealed that ILA status was a significant risk factor for ILA progression. ILAs and equivocal ILAs were associated with radiologic ILA progression after surgical resection in patients with lung cancer. Hence, early ILA detection can significantly affect clinical outcomes.

Prevalence and mortality associations of interstitial lung abnormalities in rheumatoid arthritis within a multicentre prospective cohort of smokers

OBJECTIVE

To investigate the prevalence and mortality impact of interstitial lung abnormalities (ILAs) in RA and non-RA comparators.

METHODS

We analysed associations between ILAs, RA, and mortality in COPDGene, a multicentre prospective cohort study of current and past smokers, excluding known interstitial lung disease (ILD) or bronchiectasis. All participants had research chest high-resolution CT (HRCT) reviewed by a sequential reading method to classify ILA as present, indeterminate or absent. RA cases were identified by self-report RA and DMARD use; non-RA comparators had neither an RA diagnosis nor used DMARDs. We examined the association and mortality risk of RA and ILA using multivariable logistic regression and Cox regression.

RESULTS

We identified 83 RA cases and 8725 non-RA comparators with HRCT performed for research purposes. ILA prevalence was 16.9% in RA cases and 5.0% in non-RA comparators. After adjusting for potential confounders, including genetics, current/past smoking and other lifestyle factors, ILAs were more common among those with RA compared with non-RA [odds ratio 4.76 (95% CI 2.54, 8.92)]. RA with ILAs or indeterminate for ILAs was associated with higher all-cause mortality compared with non-RA without ILAs [hazard ratio (HR) 3.16 (95% CI 2.11, 4.74)] and RA cases without ILA [HR 3.02 (95% CI 1.36, 6.75)].

CONCLUSIONS

In this cohort of smokers, RA was associated with ILAs and this persisted after adjustment for current/past smoking and genetic/lifestyle risk factors. RA with ILAs in smokers had a 3-fold increased all-cause mortality, emphasizing the importance of further screening and treatment strategies for preclinical ILD in RA.

Long-Term Follow-Up of Interstitial Lung Abnormality: Implication in Follow-Up Strategy and Risk Thresholds

Rationale: The optimal follow-up computed tomography (CT) interval for detecting the progression of interstitial lung abnormality (ILA) is unknown. Objectives: To identify optimal follow-up strategies and extent thresholds on CT relevant to outcomes. Methods: This retrospective study included self-referred screening participants aged 50 years or older, including nonsmokers, who had imaging findings relevant to ILA on chest CT scans. Consecutive CT scans were evaluated to determine the dates of the initial CT showing ILA and the CT showing progression. Deep learning-based ILA quantification was performed. Cox regression was used to identify risk factors for the time to ILA progression and progression to usual interstitial pneumonia (UIP). Measurements and Main Results: Of the 305 participants with a median follow-up duration of 11.3 years (interquartile range, 8.4-14.3 yr), 239 (78.4%) had ILA on at least one CT scan. In participants with serial follow-up CT studies, ILA progression was observed in 80.5% (161 of 200), and progression to UIP was observed in 17.3% (31 of 179), with median times to progression of 3.2 years (95% confidence interval [CI], 3.0-3.4 yr) and 11.8 years (95% CI, 10.8-13.0 yr), respectively. The extent of fibrosis on CT was an independent risk factor for ILA progression (hazard ratio, 1.12 [95% CI, 1.02-1.23]) and progression to UIP (hazard ratio, 1.39 [95% CI, 1.07-1.80]). Risk groups based on honeycombing and extent of fibrosis (1% in the whole lung or 5% per lung zone) showed significant differences in 10-year overall survival (P = 0.02). Conclusions: For individuals with initially detected ILA, follow-up CT at 3-year intervals may be appropriate to monitor radiologic progression; however, those at high risk of adverse outcomes on the basis of the quantified extent of fibrotic ILA and the presence of honeycombing may benefit from shortening the interval for follow-up scans.

Drug-induced interstitial lung disease after chemoimmunotherapy for extensive-stage small cell lung cancer

Objectives

The combination of chemotherapy and immune checkpoint inhibitors (chemo-ICI) has become the new standard of treatment for extensive-stage small cell lung cancer (ES-SCLC). Recently, slight changes in interstitial shadows, defined as interstitial lung abnormalities (ILA), have been identified. In patients with ES-SCLC who received chemo-ICI, there are limited data on the incidence of drug-induced interstitial lung disease (D-ILD) in daily practice and the association between the development of D-ILD and ILA in the baseline computed tomography (CT).

Materials and methods

A multicenter, retrospective study was conducted to investigate the incidence of D-ILD, the risk factors for developing D-ILD, progression-free survival (PFS), and overall survival (OS) in patients with ES-SCLC who received chemo-ICI between August 2019 and November 2021.

Results

This study enrolled 70 patients (median age, 71 years; including 58 men) from nine institutions in Japan. There were 62 patients (89%) treated with carboplatin/etoposide/atezolizumab and 8 patients treated with carboplatin or cisplatin/etoposide/durvalumab. Twenty-nine patients (41.4%) were found to have ILA at baseline CT. Eleven patients (15.7%) developed D-ILD. The proportion of patients with ILA was significantly higher in the group who developed D-ILD than in the group who did not (9/11 (81.8%) vs. 20/59 (33.9%), respectively, P = 0.0057). In addition, the frequency of ground glass attenuation (GGA) and reticulation was higher in patients who developed D-ILD. There was no significant difference in PFS and OS between patients who developed D-ILD and those who did not (median PFS, 8.0 (95% confidence interval (CI), 5.5-9.5) months vs. 5.0 (95% CI, 4.5-5.6) months, respectively, P = 0.11 and median OS, not reached (NR) (95% CI, 8.7-NR) vs. 18.2 (95% CI, 13.2-NR) months, respectively, P = 0.20).

Conclusion

The incidence of D-ILD in patients with ES-SCLC who received chemo-ICI in clinical practice was higher than that in clinical trials. Patients with pre-existing ILA were more likely to develop D-ILD.

Lung Imaging in COPD Part 1: Clinical Usefulness

COPD is a condition characterized by chronic airflow obstruction resulting from chronic bronchitis, emphysema, or both. The clinical picture is usually progressive with respiratory symptoms such as exertional dyspnea and chronic cough. For many years, spirometry was used to establish a diagnosis of COPD. Recent advancements in imaging techniques allow quantitative and qualitative analysis of the lung parenchyma as well as related airways and vascular and extrapulmonary manifestations of COPD. These imaging methods may allow prognostication of disease and shed light on the efficacy of pharmacologic and nonpharmacologic interventions. This is the first of a two-part series of articles on the usefulness of imaging methods in COPD, and it highlights useful information that clinicians can obtain from these imaging studies to make more accurate diagnosis and therapeutic decisions.

Associations between GrimAge acceleration and pulmonary function in the Coronary Artery Risk Development in Young Adults (CARDIA) study

Background: The objective of this research was to determine whether pulmonary function is associated with epigenetic aging (GrimAge) and whether GrimAge predicts emphysema. Methods: This prospective study examined 1042 participants enrolled as part of a community-based longitudinal cohort. The cross-sectional associations between pulmonary function and GrimAge, measured at study year (Y) 20 (participant ages 40-45 years), and prospective associations with emphysema at Y25 were examined. Results: At Y20, forced expiratory volume in 1 s (FEV1) and FEV1/forced vital capacity (FVC) were negatively associated with GrimAge; for Y0-Y10 cumulative measures, only the FEV1/FVC ratio was associated with GrimAge at Y15 and Y20. Emphysema at Y25 was associated with GrimAge at Y15 and Y20. Conclusion: Pulmonary function was associated with GrimAge during early and mid-life; GrimAge partially mediated the association between pulmonary function and emphysema.

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.

Are Interstitial Lung Abnormalities a Prognostic Factor of Worse Outcome in COVID-19 Pneumonia?

PURPOSE

To assess the association between interstitial lung abnormalities (ILAs) and worse outcome in patients affected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) disease (COVID-19)-related pneumonia.

MATERIALS AND METHODS

The study included patients older than 18 years, who were admitted at the emergency department between February 29 and April 30, 2020 with findings of COVID-19 pneumonia at chest computed tomography (CT), with positive reverse-transcription polymerase chain reaction nasal-pharyngeal swab for SARS-CoV-2, and with the availability of prepandemic chest CT. Prepandemic CTs were reviewed for the presence of ILAs, categorized as fibrotic in cases with associated architectural distortion, bronchiectasis, or honeycombing. Worse outcome was defined as intensive care unit (ICU) admission or death. Cox proportional hazards regression analysis was used to test the association between ICU admission/death and preexisting ILAs.

RESULTS

The study included 147 patients (median age 73 y old; 95% CIs: 71-76-y old; 29% females). On prepandemic CTs, ILA were identified in 33/147 (22%) of the patients, 63% of which were fibrotic ILAs. Fibrotic ILAs were associated with higher risk of ICU admission or death in patients with COVID-19 pneumonia (hazard ratios: 2.73, 95% CIs: 1.50-4.97, P =0.001).

CONCLUSIONS

In patients affected by COVID-19 pneumonia, preexisting fibrotic ILAs were an independent predictor of worse prognosis, with a 2.7 times increased risk of ICU admission or death. Chest CT scans obtained before the diagnosis of COVID-19 pneumonia should be carefully reviewed for the presence and characterization of ILAs.

Interstitial Lung Abnormalities at CT in the Korean National Lung Cancer Screening Program: Prevalence and Deep Learning-based Texture Analysis

Background Interstitial lung abnormalities (ILAs) are associated with worse clinical outcomes, but ILA with lung cancer screening CT has not been quantitatively assessed. Purpose To determine the prevalence of ILA at CT examinations from the Korean National Lung Cancer Screening Program and define an optimal lung area threshold for ILA detection with CT with use of deep learning-based texture analysis. Materials and Methods This retrospective study included participants who underwent chest CT between April 2017 and December 2020 at two medical centers participating in the Korean National Lung Cancer Screening Program. CT findings were classified by three radiologists into three groups: no ILA, equivocal ILA, and ILA (fibrotic and nonfibrotic). Progression was evaluated between baseline and last follow-up CT scan. The extent of ILA was assessed visually and quantitatively with use of deep learning-based texture analysis. The Youden index was used to determine an optimal cutoff value for detecting ILA with use of texture analysis. Demographics and ILA subcategories were compared between participants with progressive and nonprogressive ILA. Results A total of 3118 participants were included in this study, and ILAs were observed with the CT scans of 120 individuals (4%). The median extent of ILA calculated by the quantitative system was 5.8% for the ILA group, 0.7% for the equivocal ILA group, and 0.1% for the no ILA group (P < .001). A 1.8% area threshold in a lung zone for quantitative detection of ILA showed 100% sensitivity and 99% specificity. Progression was observed in 48% of visually assessed fibrotic ILAs (15 of 31), and quantitative extent of ILA increased by 3.1% in subjects with progression. Conclusion ILAs were detected in 4% of the Korean lung cancer screening population. Deep learning-based texture analysis showed high sensitivity and specificity for detecting ILA with use of a 1.8% lung area cutoff value. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Egashira and Nishino in this issue.

Subpleural fibrotic interstitial lung abnormalities are implicated in non-small cell lung cancer radiotherapy outcomes

BACKGROUND

The relationship between interstitial lung abnormalities (ILAs) and the outcomes of lung cancer radiotherapy is unclear. This study investigated whether specific ILA subtypes are risk factors for radiation pneumonitis (RP).

PATIENTS AND METHODS

This retrospective study analysed patients with non-small cell lung cancer treated with radical-intent or salvage radiotherapy. Patients were categorised into normal (no abnormalities), ILA, and interstitial lung disease (ILD) groups. The ILA group was further subclassified into non-subpleural (NS), subpleural non-fibrotic (SNF), and subpleural fibrotic (SF) types. The Kaplan-Meier and Cox regression methods were used to determine RP and survival rates and compare these outcomes between groups, respectively.

RESULTS

Overall, 175 patients (normal, n = 105; ILA-NS, n = 5; ILA-SNF, n = 28; ILA-SF, n = 31; ILD, n = 6) were enrolled. Grade ≥2 RP was observed in 71 (41%) patients. ILAs (hazard ratio [HR]: 2.33, p = 0.008), intensity-modulated radiotherapy (HR: 0.38, p = 0.03), and lung volume receiving 20 Gy (HR: 54.8, p = 0.03) contributed to the cumulative incidence of RP. Eight patients with grade 5 RP were in the ILA group, seven of whom had ILA-SF. Among radically treated patients, the ILA group had worse 2-year overall survival (OS) than the normal group (35.3% vs 54.6%, p = 0.005). Multivariate analysis revealed that the ILA-SF group contributed to poor OS (HR: 3.07, p =0.02).

CONCLUSIONS

ILAs, particularly ILA-SF, may be important risk factors for RP, which can worsen prognosis. These findings may aid in making decisions regarding radiotherapy.

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.

Impact of Interstitial Lung Abnormalities on Disease Expression and Outcomes in COPD or Emphysema: A Systematic Review

Background

Both COPD and interstitial lung abnormalities (ILAs) are conditions associated with smoking and age. The impact of coexistent ILAs on the manifestations and outcomes of COPD or emphysema awaits evaluation.

Methods

We searched PubMed and Embase using Medical Subject Headings terms in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

Results

Eleven studies were included in the review. The sample size of the studies ranged from 30 to 9579. ILAs were reported in 6.5% to 25.7% of the patients with COPD/emphysema, higher than that reported in the general populations. COPD/emphysema patients with ILAs were older, mostly male, and had a higher smoking index than those without ILAs. Hospital admission and mortality were increased in COPD patients with ILAs compared to those without ILAs, whereas the frequency of COPD exacerbations was discrepant in 2 of the studies. The FEV₁ and FEV₁% predicted tended to be higher in the group with ILAs, but not significantly in most of the studies.

Conclusion

ILAs were more frequent in subjects with COPD/emphysema than in the general population. ILAs may have a negative impact on hospital admission and mortality of COPD/emphysema. The impact of ILAs on lung functions and exacerbations of COPD/emphysema was discrepant in these studies. Further prospective studies are warranted to provide high-quality evidence of the association and interaction between COPD/emphysema and ILAs.

Associations of hiatus hernia with CT-based interstitial lung changes: the MESA Lung Study

BACKGROUND

Hiatus hernia (HH) is prevalent in adults with pulmonary fibrosis. We hypothesised that HH would be associated with markers of lung inflammation and fibrosis among community-dwelling adults and stronger among MUC5B (rs35705950) risk allele carriers.

METHODS

In the Multi-Ethnic Study of Atherosclerosis, HH was assessed from cardiac and full-lung computed tomography (CT) scans performed at Exam 1 (2000-2002, n=3342) and Exam 5 (2010-2012, n=3091), respectively. Percentage of high attenuation areas (HAAs; percentage of voxels with attenuation between -600 and -250 HU) was measured from cardiac and lung scans. Interstitial lung abnormalities (ILAs) were examined from Exam 5 scans (n=2380). Regression models were used to examine the associations of HH with HAAs, ILAs and serum matrix metalloproteinase-7 (MMP-7), and adjusted for age, sex, race/ethnicity, educational attainment, smoking, height, weight and scanner parameters for HAA analysis.

RESULTS

HH detected from Exam 5 scans was associated with a mean percentage difference in HAAs of 2.23% (95% CI 0.57-3.93%) and an increase of 0.48% (95% CI 0.07-0.89%) per year, particularly in MUC5B risk allele carriers (p-value for interaction=0.02). HH was associated with ILAs among those <80 years of age (OR for ILAs 1.78, 95% CI 1.14-2.80) and higher serum MMP-7 level among smokers (p-value for smoking interaction=0.04).

CONCLUSIONS

HH was associated with more HAAs over time, particularly among MUC5B risk allele carriers, and ILAs in younger adults, and may be a risk factor in the early stages of interstitial lung disease.

Is Thoracic Radiotherapy an Absolute Contraindication for Treatment of Lung Cancer Patients With Interstitial Lung Disease? A Systematic Review

Thoracic radiotherapy decisions in patients with interstitial lung disease (ILD) are complex due to concerns about severe or even fatal radiation pneumonitis. This systematic review analysed the published evidence regarding the incidence of radiation pneumonitis and mortality after thoracic radiotherapy and investigated clinical and dosimetric predictors of radiation pneumonitis in lung cancer patients with ILD. A systematic search was carried out in PubMed, Medline, Embase and the Cochrane database for articles published between January 2000 and April 2021. Two authors independently screened eligible studies that met our predefined criteria. Studies were assessed for design and quality and a qualitative data synthesis was carried out. The search strategy resulted in 1750 articles. After two rounds of screening, 24 publications were included. The median overall incidence of grade ≥3 radiation pneumonitis was 19.7% (range 8-46%). The incidence was greater in conventional radical radiotherapy-treated patients (median 31.8%) compared with particle beam therapy- or stereotactic ablative radiotherapy-treated patients (median 12.5%). The median rate of grade 5 radiation pneumonitis was 11.9% (range 0-60%). The presence of ILD was an independent predictor of severe radiation pneumonitis. Severe radiation pneumonitis was more common in the presence of usual interstitial pneumonia (UIP) pattern or idiopathic pulmonary fibrosis (IPF) than non-UIP or non-IPF subtype. Several other clinical predictors were reported in the literature. V5, V10, V20 and mean lung dose were the most common dosimetric predictors for severe radiation pneumonitis, often with stricter dose constraints than conventionally used. Patients with lung cancer associated with ILD had a poorer overall survival compared with patients without ILD. In conclusion, patients with lung cancer associated with ILD have a poor prognosis. They are at high risk of severe and even fatal radiation pneumonitis. Careful patient selection is necessary, appropriate high-risk consenting and strict lung dose-volume constraints should be used, if these patients are to be treated with thoracic radiotherapy.

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.

Biomarkers of interstitial lung disease associated with primary Sjögren's syndrome

Objectives

The aim of this study was to investigate serum biomarkers linked to primary Sjögren's syndrome (pSS)-associated interstitial lung disease (ILD).

Methods

69 pSS patients were consecutively enrolled and evaluated via quantitative ILD scoring based on high-resolution computed tomography (HRCT). Biomarkers of interest were assessed by multiplex enzyme-linked immunosorbent assays (ELISAs).

Results

Among consecutively enrolled patients with pSS, the presence of pSS–ILD was 50% based on the presence of radiographically defined interstitial lung abnormalities (ILA) meeting specified criteria for mild/moderate (ILA 2) or severe (ILA 3) disease. Age, immunoglobulin M (IgM), C-reactive protein (CRP), and serum levels of eotaxin/CCL11, Krebs von den Lungen-6 (KL-6), TNFα, and TGFα were significantly higher in the combined pSS–ILD group (ILA 2 + ILA 3) than in the pSS–no-ILD and pSS–indeterminate ILD groups (ILA 0 and ILA 1, respectively) in unadjusted analyses (p < 0.05 for all variables). A binary logistic regression model revealed that disease duration and KL-6 levels were associated with the presence of pSS–ILD (p < 0.05). Complementary least absolute shrinkage and selection operator (LASSO) modeling showed that age, KL-6, and TNF-α effectively differentiated pSS–ILD (ILA 2 + ILA3) from pSS without ILD (ILA 0 + ILA 1), with an area under the curve (AUC) of 0.883 (p value < 0.0001).

Conclusions

Patient age, disease duration, and serum levels of both KL-6 and TNFα were the most discriminating factors associated with the presence of ILD in our pSS patients. Higher levels of CRP, IgM, eotaxin, TGFα, and TNFα should also prompt the search for occult as well as clinically evident lung involvement based on statistically significant univariate associations with pSS–ILD.

Clinical trial registration

None.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40001-022-00828-3.

Traction Bronchiectasis/Bronchiolectasis on CT Scans in Relationship to Clinical Outcomes and Mortality: The COPDGene Study

Background The clinical impact of interstitial lung abnormalities (ILAs) on poor prognosis has been reported in many studies, but risk stratification in ILA will contribute to clinical practice. Purpose To investigate the association of traction bronchiectasis/bronchiolectasis index (TBI) with mortality and clinical outcomes in individuals with ILA by using the COPDGene cohort. Materials and Methods This study was a secondary analysis of prospectively collected data. Chest CT scans of participants with ILA for traction bronchiectasis/bronchiolectasis were evaluated and outcomes were compared with participants without ILA from the COPDGene study (January 2008 to June 2011). TBI was classified as follows: TBI-0, ILA without traction bronchiectasis/bronchiolectasis; TBI-1, ILA with bronchiolectasis but without bronchiectasis or architectural distortion; TBI-2, ILA with mild to moderate traction bronchiectasis; and TBI-3, ILA with severe traction bronchiectasis and/or honeycombing. Clinical outcomes and overall survival were compared among the TBI groups and the non-ILA group by using multivariable linear regression model and Cox proportional hazards model, respectively. Results Overall, 5295 participants (median age, 59 years; IQR, 52-66 years; 2779 men) were included, and 582 participants with ILA and 4713 participants without ILA were identified. TBI groups were associated with poorer clinical outcomes such as quality of life scores in the multivariable linear regression model (TBI-0: coefficient, 3.2 [95% CI: 0.6, 5.7; P = .01]; TBI-1: coefficient, 3.3 [95% CI: 1.1, 5.6; P = .003]; TBI-2: coefficient, 7.6 [95% CI: 4.0, 11; P < .001]; TBI-3: coefficient, 32 [95% CI: 17, 48; P < .001]). The multivariable Cox model demonstrated that ILA without traction bronchiectasis (TBI-0-1) and with traction bronchiectasis (TBI-2-3) were associated with shorter overall survival (TBI-0-1: hazard ratio [HR], 1.4 [95% CI: 1.0, 1.9; P = .049]; TBI-2-3: HR, 3.8 [95% CI: 2.6, 5.6; P < .001]). Conclusion Traction bronchiectasis/bronchiolectasis was associated with poorer clinical outcomes compared with the group without interstitial lung abnormalities; TBI-2 and 3 were associated with shorter survival. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Lee and Im in this issue.

Demographic, Lifestyle, and Serologic Risk Factors for Rheumatoid Arthritis (RA)-associated Bronchiectasis: Role of RA-related Autoantibodies

OBJECTIVE

To investigate demographic, lifestyle, and serologic risk factors for isolated rheumatoid arthritis (RA)-associated bronchiectasis (RA-BR) that is not a result of interstitial lung disease (ILD).

METHODS

We performed a case-control study using patients with RA from the Mass General Brigham Biobank. We reviewed the records of all patients with RA meeting the 2010 American College of Rheumatology/European Alliance of Associations for Rheumatology criteria with computed tomography (CT) chest imaging to identify RA-BR cases and controls with RA and RA-related lung disease. For each patient, the CT chest imaging that was performed closest to enrollment was independently reviewed by 2 radiologists for the presence of RA-related lung diseases. Cases had clinical and radiologic evidence of RA-BR without interstitial lung abnormalities on imaging. Controls had RA and no evidence of bronchiectasis or ILD. We examined the associations between demographic, lifestyle, and serologic factors with RA-BR using multivariable logistic regression.

RESULTS

We identified 57 cases of isolated RA-BR and 360 RA controls without RA-related lung disease. In multivariable models, RA-BR was associated with older age at RA onset (OR 1.37 per 10 years, 95% CI 1.02-1.82), lower BMI at RA diagnosis (OR 0.94 per kg/m2, 95% CI 0.89-0.99), seropositive RA (OR 3.96, 95% CI 1.84-8.53), positive rheumatoid factor (OR 4.40, 95% CI 2.14-9.07), and positive anticyclic citrullinated peptide (OR 3.47, 95% CI 1.65-7.31). Higher titers of RA-related autoantibodies were associated with higher odds of RA-BR.

CONCLUSION

Seropositivity, older age at RA diagnosis, and lower BMI at RA onset were associated with isolated bronchiectasis in RA that was not a result of ILD. These findings expand the list of potential risk factors for RA-BR and suggest a pathogenic link between airway inflammation and RA-related autoantibodies.

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

Predictors of long-term prognosis in rheumatoid arthritis-related interstitial lung disease

The aim of the study was to identify specific clinical and serum protein biomarkers that are associated with longitudinal outcome of RA-associated interstitial lung disease (RA-ILD). 60 RA patients with clinical and serological profiles were assessed by HRCT and pulmonary function tests (PFTs) at baseline (Year 0) and 5 years post enrollment (Year 5). Progression versus non-progression was defined based on changes in Quantitative Modified HRCT scores and PFTs over time. Specific serum protein biomarkers were assessed in serum samples at baseline and Year 5 by Multiplex enzyme-linked immunosorbent assays (ELISAs). At Year 5, 32% of patients demonstrated progressive RA-ILD, 35% were stable, and 33% improved. Baseline age and rheumatoid factor (RF) were significantly different between RA-ILD outcomes of progression vs. no-progression (p < 0.05). Changes in levels of CXCL11/I-TAC and MMP13 over 5 years also distinguished pulmonary outcomes (p < 0.05). A final binary logistic regression model revealed that baseline age and changes in serum MMP13 as well as CXCL11/I-TAC were associated with RA-ILD progression at Year 5 (p < 0.01), with an AUC of 0.7772. Collectively, these analyses demonstrated that baseline clinical variables (age, RF) and shifts in levels of selected serum proteins (CXCL11/I-TAC, MMP13) were strongly linked to RA-ILD outcome over time.

Associations of Monocyte Count and Other Immune Cell Types with Interstitial Lung Abnormalities

Rationale: Higher blood monocyte counts are associated with worse survival in adults with clinically diagnosed pulmonary fibrosis. Their association with the development and progression of interstitial lung abnormalities (ILA) in humans is unknown. Objectives: We evaluated the associations of blood monocyte count, and other immune cell types, with ILA, high-attenuation areas, and FVC in four independent cohorts. Methods: We included participants with measured monocyte counts and computed tomographic (CT) imaging enrolled in MESA (Multi-Ethnic Study of Atherosclerosis, n = 484), AGES-Reykjavik (Age/Gene Environment Susceptibility Study, n = 3,547), COPDGene (Genetic Epidemiology of COPD, n = 2,719), and the ECLIPSE (Evaluation of COPD Longitudinally to Identify Predictive Surrogate End-points, n = 646). Measurements and Main Results: After adjustment for covariates, a 1-SD increment in blood monocyte count was associated with ILA in MESA (odds ratio [OR], 1.3; 95% confidence interval [CI], 1.0-1.8), AGES-Reykjavik (OR, 1.2; 95% CI, 1.1-1.3), COPDGene (OR, 1.3; 95% CI, 1.2-1.4), and ECLIPSE (OR, 1.2; 95% CI, 1.0-1.4). A higher monocyte count was associated with ILA progression over 5 years in AGES-Reykjavik (OR, 1.2; 95% CI, 1.0-1.3). Compared with participants without ILA, there was a higher percentage of activated monocytes among those with ILA in MESA. Higher monocyte count was associated with greater high-attenuation areas in MESA and lower FVC in MESA and COPDGene. Associations of other immune cell types were less consistent. Conclusions: Higher blood monocyte counts were associated with the presence and progression of interstitial lung abnormalities and lower FVC.

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.

Screening for preclinical parenchymal lung disease in rheumatoid arthritis

OBJECTIVES

Pulmonary disease is a common extraarticular manifestation of RA associated with increased morbidity and mortality. No current strategies exist for screening this at-risk population for parenchymal lung disease, including emphysema and interstitial lung disease (ILD).

METHODS

RA patients without a diagnosis of ILD or chronic obstructive pulmonary disease underwent prospective and comprehensive clinical, laboratory, functional and radiological evaluations. High resolution CT (HRCT) scans were scored for preclinical emphysema and preclinical ILD and evaluated for other abnormalities.

RESULTS

Pulmonary imaging and/or functional abnormalities were identified in 78 (74%) of 106 subjects; 45% had preclinical parenchymal lung disease. These individuals were older with lower diffusion capacity but had similar smoking histories compared with no disease. Preclinical emphysema (36%), the most commonly detected abnormality, was associated with older age, higher anti-cyclic citrullinated peptide antibody titres and diffusion abnormalities. A significant proportion of preclinical emphysema occurred among never smokers (47%) with a predominantly panlobular pattern. Preclinical ILD (15%) was not associated with clinical, laboratory or functional measures.

CONCLUSION

We identified a high prevalence of undiagnosed preclinical parenchymal lung disease in RA driven primarily by isolated emphysema, suggesting that it may be a prevalent and previously unrecognized pulmonary manifestation of RA, even among never smokers. As clinical, laboratory and functional evaluations did not adequately identify preclinical parenchymal abnormalities, HRCT may be the most effective screening modality currently available for patients with RA.

Interstitial Lung Abnormalities, Emphysema and Spirometry in Smokers

BACKGROUND

Most pulmonary conditions reduce forced vital capacity (FVC), but studies of patients with combined pulmonary fibrosis and emphysema demonstrate that reductions in FVC are less than expected when these two conditions coexist clinically.

RESEARCH QUESTION

Do interstitial lung abnormalities (ILA), chest computed tomography (CT) imaging findings that may suggest an early stage of pulmonary fibrosis in undiagnosed individuals, affect the association between emphysema and FVC?

STUDY DESIGN AND METHODS

Measures of ILA and emphysema were available in 9579 and 5277 participants from phases 1 (2007-2011) and 2 (2012-2016) of COPDGene, respectively. ILA were defined by Fleischner Society guidelines. Adjusted linear regression models were used to assess the associations and interactions between ILA, emphysema, measures of spirometry and lung function.

RESULTS

ILA were present in 528 (6%), and 580 (11%), of participants in phases 1 and 2 of COPDGene, respectively. ILA modified the association between emphysema and FVC (P<0.0001 for interaction) in both phases. In phase 1, in those without ILA, a 5% increase in emphysema was associated with a reduction in FVC (-110 cc, 95% confidence interval [CI] -121, -100; P<0.0001) however, in those with ILA it was not (-11cc, 95% CI -53,31; P=0.59). In contrast, there was no interaction between ILA and emphysema on total lung capacity (TLC) nor on diffusing capacity of carbon monoxide (DLCO).

INTERPRETATION

The presence of ILA attenuates the reduction in FVC associated with emphysema.

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.

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.

Unclassifiable, or simply unclassified interstitial lung disease?

PURPOSE OF REVIEW

Unclassifiable interstitial lung disease (ILD) comprises a subset of ILDs which cannot be classified according to the current diagnostic framework. This is a likely a heterogeneous group of diseases rather than a single entity and it is poorly defined and hence problematic for prognosis and therapy.

RECENT FINDINGS

With increased treatment options for progressive fibrosing ILD it is increasingly relevant to correctly categorise ILD.

SUMMARY

This review article will summarise the definition and reasons for a diagnosis of unclassifiable ILD, the current management options and possible future approaches to improve diagnosis and differentiation within this broad subset. Finally, we will describe the implications of the labelling of unclassifiable ILD in clinical practice and research and whether the term 'unclassified' should be used, implying a less definitive diagnosis.