Association Between Interstitial Lung Abnormalities and All-Cause Mortality

A Comprehensive Review of Interstitial Lung Abnormalities

Interstitial lung abnormalities (ILAs) represent radiological entities that comprise changes compatible with an interstitial process, occurring in individuals not suspected to have interstitial lung disease (ILD). The prevalence of ILAs ranges from 2.5% to 16.7% in lung cancer screening and population-based cohorts. ILAs have consistently been associated with mortality. Risk factors include older age, smoking, and genetic polymorphisms such as MUC5B. Progression of ILAs occurs in 20%-76% of cases over 2-6 years of follow-up. The clinical approach to ILAs involves risk stratification based on radiological features, extent of involvement, and associated clinical and physiological findings. ILAs pose a significant challenge in distinguishing inconsequential radiological findings from early ILD. This review summarises the current understanding of ILAs, including prevalence, risk factors, progression, associated biomarkers, and clinical management strategies.

Association of Preserved Ratio Impaired Spirometry and Mortality Outcomes Compared With Normal Spirometry: A Meta-Analysis

Background: One of the leading causes of death in the United States is chronic lung disease, with COPD being the most common. One of the hallmarks of COPD is spirometric obstruction as evidenced by a reduced FEV1/FVC ratio. Preserved ratio impaired spirometry (PRISm) is a spirometric pattern characterized as a low FEV1 coupled with a preserved FEV1/FVC ratio. This systematic review and meta-analysis sought to understand better the relationship between PRISm and cardiovascular, respiratory, and all-cause mortality. Methods: We systematically searched PubMed and clinicaltrials.gov for articles published between 2014 and 2023, providing data regarding the association of PRISm compared with normal spirometry in terms of morality outcomes. The generic inverse variance method was used to assess the pooled hazard ratio value at a 95% CI, and forest plots were created using RevMan for analysis. P < .05 was considered to be significant. Results: Our analysis included 690,015 subjects from four prospective studies and three retrospective studies. The pooled hazard ratio for all-cause, cardiovascular, and respiratory-related mortality was 1.70, 1.95, and 5.70 for all prospective studies, respectively, and 1.62, 1.66, and 3.35, in combined prospective and retrospective studies, respectively, which were statistically significant in the random effect model (P < .001). However, 76% heterogeneity was observed in respiratory-related mortality (P = .009). After excluding studies associated with publication bias, a "leave-out" sensitive analysis resulted in a significant pooled hazard ratio of 1.98 with a high significance (P < .001). Conclusions: PRISm, often labeled as GOLD-U, is associated with mortality outcomes and should not be overlooked while treating patients with chronic lung diseases. This meta-analysis provides a stronger correlation of PRISm with all-cause mortality, cardiovascular mortality, and respiratory mortality compared with normal spirometry.

Immunotherapeutic targeting of aging-associated isoDGR motif in chronic lung inflammation

Accumulation of damaged biomolecules in body tissues is the primary cause of aging and age-related chronic diseases. Since this damage often occurs spontaneously, it has traditionally been regarded as untreatable, with typical therapeutic strategies targeting genes or enzymes being ineffective in this domain. In this report, we demonstrate that an antibody targeting the isoDGR damage motif in lung tissue can guide immune clearance of harmful damaged proteins in vivo, effectively reducing age-linked lung inflammation. We observed age-dependent accumulation of the isoDGR motif in human lung tissues, as well as an 8-fold increase in isoDGR-damaged proteins in lung fibrotic tissues compared with healthy tissue. This increase was accompanied by marked infiltration of CD68+/CD11b + macrophages, consistent with a role for isoDGR in promoting chronic inflammation. We therefore assessed isoDGR function in mice that were either naturally aged or lacked the isoDGR repair enzyme. IsoDGR-protein accumulation in mouse lung tissue was strongly correlated with chronic inflammation, pulmonary edema, and hypoxemia. This accumulation also induced mitochondrial and ribosomal dysfunction, in addition to features of cellular senescence, thereby contributing to progressive lung damage over time. Importantly, treatment with anti-isoDGR antibody was able to reduce these molecular features of disease and significantly reduced lung pathology in vivo.

Analysis of baseline interstitial lung abnormality on the risk of checkpoint inhibitor-related pneumonitis and survival in advanced non-small cell lung cancer patients treated with first-line PD-1/PD-L1 inhibitors

Background

Chest computed tomography (CT) can be used to identify interstitial lung abnormality (ILA), which is known to lead to an increased risk of post-operative complications, and is related to a worse prognosis in early-stage lung cancer. However, research on the role of ILA in advanced non-small cell lung cancer (NSCLC) patients receiving immunotherapy is limited. This study sought to investigate the effect of pre-existing ILA and pulmonary function test (PFT) results on the occurrence of checkpoint inhibitor-related pneumonitis (CIP) and survival in advanced NSCLC patients after programmed cell death protein-1 (PD-1) or programmed cell death-ligand 1 (PD-L1) inhibitor therapy.

Methods

We retrospectively divided the patients with advanced NSCLC into two groups: the with ILA group, and the without ILA group. We also divided the patients into two groups based on whether they developed CIP during treatment. After first-line immunotherapy, we followed up with all patients and recorded their progression-free survival (PFS) and overall survival (OS). Two respiratory specialists recorded the cases of CIP and the existence of ILA on chest CT, and assessed the consistency of ILA. A logistic regression analysis was performed to explore the independent risk factors for CIP, and a Cox regression analysis was performed to investigate the factors influencing PFS and OS.

Results

Of the 269 patients with advanced NSCLC enrolled in the study, 93 (34.57%) had ILA, and 176 (65.43%) did not have ILA. Additionally, 39 (14.50%) of the patients developed CIP. The univariate analysis showed that pre-existing ILA [odds ratio (OR): 3.733; 95% confidence interval (CI): 1.846-7.549; P<0.001], body mass index (BMI) (≥24.12 kg/m2) (OR: 2.616; 95% CI: 1.312-5.214; P=0.006), and lactate dehydrogenase (LDH) (≥186.50 U/L) (OR: 2.231; 95% CI: 1.038-4.792; P=0.04) were highly correlated with CIP. In the multivariate analysis, ILA remained a robust independent predictor of CIP (OR: 4.128; 95% CI: 1.984-8.587; P<0.001). In terms of CIP, compared to the patients with mild CIP (grades 1/2), those with severe CIP (grades 3/4) had a worse OS (median for patients with grades 3/4: 12.4 months; median for patients with grades 1/2: 35.8 months) [hazard ratio (HR): 4.808; 95% CI: 1.671-13.830; P=0.004]. ILA was linked to a shorter OS time, such that the patients with ILA had a median OS of 21.1 months, while those without ILA had a median OS of 42.5 months (HR: 2.213; 95% CI: 1.404-3.488; P<0.001). The multivariable Cox regression analysis showed that ILA was also significantly associated with an increased risk of death (HR: 1.899; 95% CI: 1.253-2.878; P=0.002). However, no significant association was found between the PFTs before immunotherapy and CIP.

Conclusions

Pre-existing ILA is an independent risk factor that is strongly associated with CIP, and significantly correlated with worse PFS and OS in advanced NSCLC patients after first-line immunotherapy.

Krebs von den Lungen-6 as a biomarker for distinguishing between interstitial lung disease and interstitial lung abnormalities based on computed tomography findings

Background

Krebs von den Lungen-6 (KL-6), predominantly expressed by type II alveolar cells, is linked to the prognosis and severity of interstitial lung disease (ILD). This investigation sought to explore the relationship between KL-6 concentrations and the presence of ILD versus interstitial lung abnormalities (ILA).

Methods

This single-center retrospective study included 147 patients who were suspected of ILD and underwent KL-6 testing between October 2022 and March 2023. Epidemiological and clinical details of the patients, including the outcomes of pulmonary function tests and computed tomography findings, were retrospectively extracted from electronic medical records.

Results

The average age within the cohort was 77.1 years, with 97.3% (143 patients) being male. Notably, the ILA group displayed significantly reduced levels of KL-6 compared to the ILD group (411.6±298.8 vs. 968.8±901.9 U/mL, P<0.001). Utilizing a threshold of 410 U/mL for KL-6, the diagnostic performance yielded an area under the curve (95% CI) of 0.727 (0.605-0.849), demonstrating a sensitivity of 80.8% and a specificity of 64.7%.

Conclusions

Our findings indicate that serum KL-6 concentrations are markedly elevated in patients with clinically recognized and treated ILD compared to those identified with ILA. Furthermore, the association between higher KL-6 levels and reduced forced vital capacity percentage underlines the biomarker's potential in differentiating between ILD requiring intervention and less severe abnormalities.

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, physiologic 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.

Progressive Pulmonary Fibrosis and Interstitial Lung Abnormalities: AJR Expert Panel Narrative Review

Progressive pulmonary fibrosis (PPF) and interstitial lung abnormalities (ILA) are relatively new concepts in interstitial lung disease (ILD) imaging and clinical management. Recognition of signs of PPF and identification and classification of ILA are important tasks during chest high-resolution CT interpretation to optimize management of patients with ILD and those at risk of developing ILD. However, in professional society guidance, the role of imaging surveillance remains unclear for stable patients with ILD, asymptomatic patients with ILA who are at risk of progression, and asymptomatic patients at risk of developing ILD without imaging abnormalities. In this AJR Expert Panel Narrative Review, we summarize the current knowledge regarding PPF and ILA and describe the range of clinical practice with respect to imaging patients with ILD, those with ILA, and those at risk of developing ILD. In addition, we offer suggestions to help guide surveillance imaging in areas with an absence of published guidelines, where such decisions are currently driven primarily by local pulmonologists' preference.

Prognosis of Equivocal Interstitial Lung Abnormalities in a Health Check-up Population

Rationale: Equivocal interstitial lung abnormality (ILA) involves less than 5% of any lung zone or presents unilaterally without satisfying the diagnostic criteria for ILA. However, the prevalence and prognosis of equivocal ILA are unknown. Objectives: We sought to investigate the prevalence and long-term prognosis of equivocal ILA. Methods: This retrospective cohort study included individuals who underwent chest computed tomography as part of a health check-up program in 2010 at St. Luke's International Hospital in Tokyo, Japan. ILA and equivocal ILA were diagnosed using the Fleischner Society criteria. The primary outcome was the annual rate of forced vital capacity (FVC) decline in the groups with ILA, equivocal ILA, and no ILA, evaluated using a mixed-effects model. Radiological progression was also evaluated. Results: Among the 20,896 individuals included in the study, ILA and equivocal ILA were present in 2.0% (95% confidence interval = 1.8-2.2) and 0.4% (95% confidence interval = 0.4-0.5) of individuals, respectively. Follow-up pulmonary function tests were available for 18,101 (87%) individuals, with a median follow-up time of 8.3 years (interquartile range = 4.0-9.0). Individuals with equivocal ILA showed a significantly greater rate of FVC decline than those without ILA (-36.7 vs. -27.7 ml/yr; P = 0.008). Of the 86 individuals with equivocal ILA, 20 (23%) exhibited progression during the follow-up period; of these, 19 progressed to definite ILA. Conclusions: Individuals with equivocal ILA showed a significant tendency for FVC decline compared with those without ILA. A considerable number of cases progressed to definite ILA, warranting careful attention. Clinicians should be aware that even mild interstitial changes that do not meet the current criteria for ILA may deteriorate.

Antinuclear antibodies and progression of quantitative interstitial lung changes: The Multi-Ethnic Study of Atherosclerosis (MESA)-Lung Study

Antinuclear antibodies (ANA) are often found in ILD; whether ANA is associated with radiographic progression of quantitive interstitial lung changes is unknown. We performed longitudinal analyses of adults in the Multi-Ethnic Study of Atherosclerosis using linear mixed effects models with random intercept and slope to evaluate whether baseline ANA was associated with change in the amount of lung with high attenuation areas on CT (HAAs, percentage of imaged lung with -600 to -250 HU). In 6,638 subjects with 17,293 CT scans over 18 years, 741 (11 %) were ANA positive. ANA was not associated with HAA progression with ANA as a dichotomous variable (0.13 % less progression per year for ANA positive vs negative, 95%CI -0.33 %-0.07 %, p = 0.19) or as a continuous variable (0.004 % less progression per year per 10 % increase in ANA, 95%CI -0.01 %-0.005 %, p = 0.37). ANA was not associated with progression of HAA in community dwelling adults.

Current perspectives on interstitial lung abnormalities

Interstitial lung abnormalities (ILAs) are early indicators of interstitial lung disease, often identified incidentally via computed tomography of the chest. This review explores the diagnostic criteria for ILAs as outlined by the Fleischner Society, highlights associated risk factors, examines their impact on patient outcomes, and discusses management strategies. The prevalence of ILAs varies significantly, ranging from 3% to 17% across populations. Key risk factors include advanced age, smoking status, and underlying genetic predispositions. Recent advancements in imaging analysis, particularly through automated quantitative systems, have enhanced the accuracy of ILA detection. Although often subtle in presentation, ILAs hold clinical significance due to their associations with impaired lung function, progressive fibrosis, and increased mortality. Therefore, monitoring and management plans should be individualized to the risk profile of patients. Further studies are needed to refine ILA diagnostic criteria, enhance our understanding of their clinical implications, and establish optimal timing for therapeutic interventions.

Interstitial Lung Abnormalities: Unraveling the Journey from Incidental Discovery to Clinical Significance

Interstitial lung abnormalities (ILAs) are incidental radiologic abnormalities on chest computed tomography (CT) examination performed on people in whom interstitial lung disease (ILD) is not suspected. Despite the fact that most of these individuals are asymptomatic, ILAs are not synonymous with subclinical ILD, as a subset of them have symptoms and lung function impairment. On the other hand, not all ILAs progress to clinically significant ILD. Specific imaging features and patterns have been proven more likely to progress, while some individuals may comprise a higher risk group for progression. Numerous studies have demonstrated that ILAs are not only associated with an increased risk of progression toward pulmonary fibrosis and fibrosis-related mortality but are also linked to a greater incidence of lung cancer and a higher rate of all-cause mortality. Considering that the systematic evaluation of large cohorts has shown a prevalence of ILAs up to 7% and that the natural history of ILAs is unclear, successful screening and appropriate monitoring of ILAs is of particular significance for earlier diagnosis, risk factor modification, and treatment. The present review aims to summarize the current knowledge on ILAs and highlight the need to define those at greatest risk of progression to ILD and worse clinical outcomes.

Mortality and Predictive Factors for Death Following the Diagnosis of Interstitial Lung Disease in Patients with Rheumatoid Arthritis: A Retrospective, Long-Term Follow-Up Study

Objective: The aim of this study was to determine mortality and predictive factors for death in patients with rheumatoid arthritis (RA) diagnosed with and without interstitial lung disease (ILD). Methods: We retrospectively performed a long-term follow-up study of patients diagnosed with RA at our medical center between April 2001 and June 2023. The diagnosis and classification of ILD were made based on pulmonary high-resolution computed tomography (HRCT), taken at RA diagnosis and during follow-up. Results: Among 781 patients with RA, 78 were diagnosed with ILD; all cases except one were subclinical. The most common HRCT pattern was definite usual interstitial pneumonia (UIP) followed by nonspecific interstitial pneumonia (NSIP)/UIP, probable UIP, NSIP, and early UIP. During follow-up (mean of 10.0 years), the crude incidence rate of death (95% confidence interval [CI]) was 7.1 (5.2-10.0) and 1.5 (1.0-1.9) per 100 person-years in RA patients with and without ILD. Poor control of RA activity was associated with increased incidence rates of death. The standardized mortality ratio (95% CI) compared with the general population was 1.32 (1.11-1.53) for all RA patients, 2.09 (1.45-2.73) for RA-ILD patients, and 1.16 (0.95-1.38) for non-ILD RA patients. Lung cancer and respiratory failure were the most common causes of death in RA-ILD patients. The Multivariable Fine-Gray regression analysis revealed that ILD (adjusted hazard ratio [HR] 2.97 [95% CI 1.95-4.53]), advanced age (1.08 per additional year [1.05-1.10]), and low body mass index (3.07 [2.10-4.49]) were strong predictive factors for mortality in RA patients. HRCT patterns did not affect the risk of death in RA-ILD patients. Conclusions: Regardless of HRCT pattern, RA-ILD contributes to the increased mortality risk in patients with RA.

Predictive factors of fibrotic interstitial lung abnormality on high-resolution computed tomography scans: a prospective observational study

BACKGROUND

Fibrotic types of interstitial lung abnormalities seen on high-resolution computed tomography scans, characterised by traction bronchiolectasis/bronchiectasis with or without honeycombing, are predictors of progression and poor prognostic factors of interstitial lung abnormalities. There are no reports on the clinical characteristics of fibrotic interstitial lung abnormalities on high-resolution computed tomography scans. Therefore, we aimed to examine these clinical characteristics and clarify the predictive factors of fibrotic interstitial lung abnormalities on high-resolution computed tomography scans.

METHODS

Clinical and paraclinical data of 164 patients enrolled in the initial year of a multicentre prospective observational study (Kumamoto interstitial lung abnormalities study in Japan) involving over 62,000 examinees during routine health examinations were analysed. Clinical laboratory evaluations are expressed as medians and interquartile ranges for each evaluation time point, and boxplots were created for graphical representation. The percentages of abnormal clinical laboratory results were compared between the groups using chi-square or Fisher's exact tests. Univariate or multivariate logistic regression analyses were performed to analyse the relationship between fibrotic interstitial lung abnormalities and other clinical factors.

RESULTS

Fibrotic interstitial lung abnormalities were observed on high-resolution computed tomography scans in 135 (82%) patients at the time of diagnosis. Multivariate analysis showed that older age (Odds ratio, 1.06; 95% confidence interval, 1.01-1.12; p = 0.021), auscultatory fine crackles (Odds ratio, 3.39; 95% confidence interval, 1.33-8.65; p < 0.01), and elevated serum surfactant protein-D (Odds ratio, 2.68; 95% confidence interval, 1.02-8.64; p = 0.045) were independent predictive factors of fibrotic interstitial lung abnormalities. The predicted area under the curve of the fibrotic interstitial lung abnormalities based on these three factors was 0.77 (95% confidence interval, 0.68-0.86). The proportion of undecided diagnoses in the fibrotic interstitial lung abnormalities group (14%) was significantly lower than that in the non-fibrotic interstitial lung abnormalities group (41%) (p = 0.0027).

CONCLUSIONS

Fine crackles on auscultation and elevated serum surfactant protein-D levels are predictors of fibrotic interstitial lung abnormalities in older patients with interstitial lung abnormalities. These findings may assist non-radiological physicians in referring patients to specialists for early intervention in progressive fibrotic interstitial lung diseases.

TRIAL REGISTRATION NUMBER/DATE

UMIN000045149/2021.12.1.

Fibroblasts in rheumatoid arthritis: novel roles in joint inflammation and beyond

High-throughput technologies in human and animal studies have revealed novel molecular and cellular pathways involved in tissue inflammation of rheumatoid arthritis (RA). Fibroblasts have been in the forefront of research for several decades. Subpopulations with specific phenotypic and functional properties have been characterized both in mouse models and human disease. Data supporting the active involvement of fibroblasts in immune responses and tissue remodeling processes, as well as their central role in promoting clinical relapses and contributing to treatment resistance, have clearly reshaped their role in disease evolution. The lung is an important non-synovial component of RA both from a clinical and an immunopathogenic aspect. Interstitial lung disease (ILD) is a significant contributor to disease burden affecting morbidity and mortality. Although our knowledge of ILD has progressed, significant gaps in both basic and clinical science remain, posing hurdles to efficient diagnosis, prediction of disease course and its effective treatment. The specific role and contribution of fibroblasts to this process has not been clearly defined. The focus of this review is on fibroblasts and their contribution to RA and RA-ILD, presenting data on genetics and immune responses associated with RA-ILD in humans and animal models.

Recent trends in scientific research in chest radiology: What to do or not to do? That is the critical question in research

Hereby inviting young rising stars in chest radiology in Japan for contributing what they are working currently, we would like to show the potentials and directions of the near future research trends in the research field. I will provide a reflection on my own research topics. At the end, we also would like to discuss on how to choose the themes and topics of research: What to do or not to do? We strongly believe it will stimulate and help investigators in the field.

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.

Prevalence and clinical features of interstitial lung disease in patients with psoriasis

BACKGROUND

Despite the autoimmune nature of psoriasis, the potential association between psoriasis and interstitial lung disease (ILD) remains underexplored. This study aimed to investigate the frequency and clinical features of ILD in patients with psoriasis and propose a new conceptual framework of "ILD associated with psoriasis".

METHODS

A retrospective analysis of 117 patients with psoriasis was conducted, excluding those without chest imaging prior to methotrexate or biologic use and those with other comorbidities leading to ILD.

RESULTS

ILD was identified in 12 (10%) patients with psoriasis; 6/50 with psoriasis vulgaris and 6/65 with psoriatic arthritis. Three of 12 patients had no history of smoking. Serum Krebs von den Lungen-6 (KL-6) levels were elevated in patients with ILD compared to those in patients without ILD. The indeterminate for usual interstitial pneumonia (UIP) pattern was the most prevalent CT finding. A lung biopsy specimen from a representative case revealed equivalent indeterminate for UIP. Over a median 8.9-year observation period, ILD progressed in only 5 patients, with no cases of respiratory failure or death due to ILD progression, suggesting generally favourable prognoses.

CONCLUSIONS

ILD associated with psoriasis would be present, and its frequency is 10% of patients with psoriasis. We propose that chest radiography and a serum KL-6 test at the initial diagnosis of psoriasis would be useful in screening for the detection of ILD. We also recommend that a physician diagnosing ILD should carefully examine the skin findings, considering if psoriasis could be associated with ILD.

TRIAL REGISTRATION

Not applicable.

Optimizing prone CT use for suspected interstitial lung abnormalities

OBJECTIVES

We investigated whether supine chest CT alone suffices for diagnosing ILAs, thereby reducing the need for prone chest CT.

MATERIALS AND METHODS

Patients who underwent prone chest CT for suspected ILAs from January 2021 to July 2023, with matching supine CT within 1 year, were retrospectively evaluated. Five multinational thoracic radiologists independently rated ILA suspicion and fibrosis scores (1 to 5-point) and ILA extent (1-100%) using supine CT first, then combined supine-prone CT after a 1-month washout. We categorized ILA suspicion and fibrosis scores into four diagnostic groups; normal, non-fibrotic, indeterminate-type, and fibrotic ILAs. The areas under the receiver operating characteristic curve (AUCs) of ILA suspicion scores, inter-reader agreement on diagnostic categories, and intra-reader/inter-reader reliability for ILA extent were evaluated.

RESULTS

This study included 69 patients (mean age 67.2 ± 7.2 years; 36 women), with 23 age- and sex-matched patients in each group: normal, non-fibrotic ILAs, and fibrotic ILAs. The pooled AUC for ILA suspicion and inter-reader agreement on diagnostic categories improved for non-fibrotic ILAs with prone CT (AUC 0.76 to 0.92, p < 0.001; Fleiss kappa 0.25 to 0.51, p = 0.004), but not for fibrotic ILAs (AUC 0.94 to 0.99, p = 0.06; Fleiss kappa 0.63 to 0.72, p = 0.08). ILA extent was 1-2% smaller with prone CT for both ILA types (p < 0.001).

CONCLUSION

For fibrotic ILAs, supine CT alone exhibited substantial diagnostic accuracy and inter-reader agreement, while the diagnosis of non-fibrotic ILAs benefited from adding prone CT. Supine CT alone slightly overestimated extent regardless of ILA type.

KEY POINTS

Question Prone CT is recommended when interstitial lung abnormalities (ILAs) are suspected on supine CT, but its benefits remain underexplored. Findings Supine CT alone sufficed for diagnosing fibrotic ILAs, while prone CT improved non-fibrotic ILA diagnosis and reduced extent overestimation for both types. Clinical relevance Omitting prone CT reduces extra time, space, and radiation exposure without compromising the diagnosis of fibrotic ILAs, which have higher rates of progression and mortality risks, enhancing patient comfort and simplifying patient management.

Progressive Early Interstitial Lung Abnormalities in Persons at Risk for Familial Pulmonary Fibrosis: A Prospective Cohort Study

Rationale: Relatives of patients with familial pulmonary fibrosis (FPF) are at increased risk to develop FPF. Interstitial lung abnormalities (ILAs) are a radiologic biomarker of subclinical disease, but the implications of very mild abnormalities remain unclear. Objectives: To quantify the progression risk among FPF relatives with abnormalities below the threshold for ILAs as described by the Fleischner Society and to describe the characteristics of participants with new or progressive ILAs during observation. Methods: Asymptomatic FPF relatives undergo serial screening high-resolution chest computed tomography. For this analysis, early ILAs (no minimum threshold of lung involvement) were subclassified as mild (all interstitial abnormalities involve <5% of a lung zone) or moderate (any abnormality involves >5%). Identification of new or progressive ILAs on high-resolution chest computed tomography and the development of pulmonologist-diagnosed clinical FPF were defined as progression. Covariate-adjusted logistic regression identified progression-associated characteristics. Measurements and Main Results: From 2008 to 2023, 273 participants in follow-up procedures were 53.2 ± 9.4 years of age at enrollment, 95 (35%) were men, and 73 of 268 (27%) were ever-smokers. During a mean follow-up period of 6.2 ± 3.0 years, progression occurred among 31 of 211 (15%) of those with absence of ILAs at enrollment, 32 of 49 (65%) of those with mild ILAs, and 10 of 13 (77%) of those with moderate ILAs. Subjects with mild ILAs had 9.15 (95% confidence interval, 4.40-19.00; P < 0.0001) times and those with moderate ILAs had 17.14 (95% confidence interval, 4.42-66.49; P < 0.0001) times the odds of progression as subjects without ILAs. Conclusions: In persons at risk for FPF, minor interstitial abnormalities, including reticulation that is unilateral or involves <5% of a lung zone, frequently represent subclinical disease.

Association of Ground-Glass Opacities with Systemic Inflammation and Progression of Emphysema

Rationale: Ground-glass opacities (GGOs) in the absence of interstitial lung disease are understudied. Objectives: To assess the association of GGOs with white blood cells (WBCs) and progression of quantified chest computed tomography emphysema. Methods: We analyzed data of participants in the SPIROMICS study (Subpopulations and Intermediate Outcome Measures in COPD Study). Chest radiologists and pulmonologists labeled regions of the lung as GGOs, and the adaptive multiple feature method (AMFM) trained the computer to assign those labels to image voxels and quantify the volume of the lung with GGOs (%GGOAMFM). We used multivariable linear regression, zero-inflated negative binomial, and proportional hazards regression models to assess the association of %GGOAMFM with WBCs, changes in percentage emphysema, and clinical outcomes. Measurements and Main Results: Among 2,714 participants, 1,680 had chronic obstructive pulmonary disease (COPD) and 1,034 had normal spirometry. Among participants with COPD, on the basis of multivariable analysis, current smoking and chronic productive cough were associated with higher %GGOAMFM. Higher %GGOAMFM was cross-sectionally associated with higher WBC and neutrophil concentrations. Higher %GGOAMFM per interquartile range at visit 1 (baseline) was associated with an increase in emphysema at 1-year follow-up visit by 11.7% (relative increase; 95% confidence interval, 7.5-16.1%; P < 0.001). We found no association between %GGOAMFM and 1-year FEV1 decline, but %GGOAMFM was associated with exacerbations and all-cause mortality during a median follow-up of 1,544 days (interquartile interval, 1,118-2,059). Among normal spirometry participants, we found similar results, except that %GGOAMFM was associated with progression to COPD at 1-year follow-up. Conclusions: Our findings suggest that GGOAMFM is associated with increased systemic inflammation and emphysema progression.

Development, Progression, and Mortality of Suspected Interstitial Lung Disease in COPDGene

Rationale: Some with interstitial lung abnormalities (ILA) are suspected to have interstitial lung disease (ILD), a subgroup with adverse outcomes. Rates of development and progression of suspected ILD and their effect on mortality are unknown. Objectives: To determine rates of development, progression, and mortality in those with suspected ILD and assess effects of individual ILD and progression criteria. Methods: Participants from COPDGene (Genetic Epidemiology of Chronic Obstructive Pulmonary Disease) with ILA characterization and FVC at enrollment and 5-year follow-up were included. ILD was defined as ILA and fibrosis and/or FVC < 80% predicted. Prevalent ILD was assessed at enrollment and incident ILD and progression were assessed at 5-year follow-up. Computed tomography (CT) progression was assessed visually and FVC decline as relative change. Multivariable Cox regression tested associations between mortality and prevalent ILD, incident ILD, and progression groups. Measurements and Main Results: Of 9,588 participants at enrollment, 268 (2.8%; 51% of ILA) had prevalent ILD. Those with prevalent ILD had 51% mortality after median 10.6 years, which was higher than those with ILA without prevalent ILD (henceforth ILA) (33%; hazard ratio [HR], 2.0; P < 0.001). The subgroup of prevalent ILD with only fibrosis criteria (FVC ≥ 80%) had worse mortality (58%) than ILA (HR, 2.2; P < 0.001). A total of 98 participants with prevalent ILD completed 5-year follow-up: 33% had stable CT and relative FVC decline <10%, 6% had FVC decline ≥10% only, 39% had CT progression only, and 22% had both CT progression and FVC decline ≥10%. Mortality rates were 31%, 50%, 45%, and 45%, respectively; those with only CT progression had worse mortality than those with ILA (HR, 2.6; P = 0.005). At 5-year follow-up, incident ILD occurred in 148/4,842 participants without prevalent ILD (5.5/1,000 person-years) and had worse mortality than ILA (HR, 2.4; P < 0.001). Conclusion: Rates of mortality and progression are high among those with suspected ILD in COPDGene; fibrosis and radiologic progression are important predictors of mortality.

COPD and Immune Checkpoint Inhibitors for Cancer: A Literature Review

Purpose

Immune checkpoint inhibitors are a standard treatment option for many patients with cancer and are most frequently used to treat lung cancer. Chronic obstructive pulmonary disease (COPD) is the most common comorbidity of patients with lung cancer. As the cancer-specific survival of patients with lung cancer continues to increase with modern treatments, it is critical to optimize comorbidities to improve overall survival. This literature review aimed to summarize current research on the impact of COPD upon immunotherapy outcomes.

Methods

A comprehensive search was conducted in the PubMed database using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Inclusion criteria focused on peer-reviewed articles published between 2010 and 2024 that addressed COPD, cancer, and immune checkpoint inhibitors. The study team screened the studies for relevance and then synthesized them narratively.

Results

This review identified 37 studies that met the inclusion criteria. Findings suggest that COPD is predictive of improved efficacy but slightly worse toxicity from immune checkpoint inhibitor therapy. The chronic inflammation of COPD leads to immune exhaustion including the overexpression of immune checkpoints on T-cells. Particularly within "hot" tumors that have higher concentrations of tumor-infiltrating lymphocytes, the COPD-related increase in programmed cell death protein 1 (PD-1) signaling likely creates sensitivity to immune checkpoint inhibitors. However, COPD can also lead to respiratory dysfunction, debility, and interstitial lung disease; each of which increases the severity of immune-related adverse events.

Conclusion

COPD is a critical comorbidity that has a significant impact on many patients with cancer who receive treatment with immune checkpoint inhibitors. Future research is needed to design interventions to optimize COPD care in this high-risk patient population.

Preacinar Arterial Dilation Mediates Outcomes of Quantitative Interstitial Abnormalities in the COPDGene Study

Rationale: Quantitative interstitial abnormalities (QIAs) are a computed tomography (CT) measure of early parenchymal lung disease associated with worse clinical outcomes, including exercise capacity and symptoms. The presence of pulmonary vasculopathy in QIAs and its role in the QIA-outcome relationship is unknown. Objectives: To quantify radiographic pulmonary vasculopathy in QIAs and determine whether this vasculopathy mediates the QIA-outcome relationship. Methods: Ever-smokers with QIAs, outcomes, and pulmonary vascular mediator data were identified from the Genetic Epidemiology of COPD (COPDGene) study cohort. CT-based vascular mediators were right ventricle-to-left ventricle ratio, pulmonary artery-to-aorta ratio, and preacinar intraparenchymal arterial dilation (pulmonary artery volume, 5-20 mm2 in cross-sectional area, normalized to total arterial volume). Outcomes were 6-minute walk distance and a modified Medical Council Research Council Dyspnea Scale score of 2 or higher. Adjusted causal mediation analyses were used to determine whether the pulmonary vasculature mediated the QIA effect on outcomes. Associations of preacinar arterial dilation with select plasma biomarkers of pulmonary vascular dysfunction were examined. Measurements and Main Results: Among 8,200 participants, QIA burden correlated positively with vascular damage measures, including preacinar arterial dilation. Preacinar arterial dilation mediated 79.6% of the detrimental impact of QIA on 6-minute walk distance (56.2-100%; P < 0.001). Pulmonary artery-to-aorta ratio was a weak mediator, and right ventricle-to-left ventricle ratio was a suppressor. Similar results were observed in the relationship between QIA and modified Medical Council Research Council dyspnea score. Preacinar arterial dilation correlated with increased pulmonary vascular dysfunction biomarker levels, including angiopoietin-2 and N-terminal brain natriuretic peptide. Conclusions: Parenchymal QIAs deleteriously impact outcomes primarily through pulmonary vasculopathy. Preacinar arterial dilation may be a novel marker of pulmonary vasculopathy in QIAs.

Lung cancer with comorbid interstitial pneumonia: Current situation and animal model development

Interstitial pneumonia includes a range of disorders affecting the lung interstitium, significantly impacting life expectancy, especially during acute exacerbations. Concurrently, lung cancer remains a leading cause of cancer-related deaths worldwide. The coexistence of these two conditions presents a formidable challenge, complicating diagnosis, treatment, and prognosis. This review explores the critical issues associated with lung cancer comorbid with interstitial pneumonia, focusing on diagnostic challenges, prognosis, treatment complications, and the lack of effective research tools. Diagnosing lung cancer in patients with interstitial pneumonia is complicated due to overlapping imaging features and the risks associated with biopsies. The prognosis is poorer for patients with both conditions, as interstitial pneumonia promotes a more aggressive lung cancer phenotype. Standard treatment for interstitial pneumonia can inadvertently facilitate lung cancer progression, while anticancer therapies often exacerbate interstitial pneumonia. To address the lack of appropriate research tools, a novel murine model combining orthotopic lung cancer cell transplantation with bleomycin-induced interstitial pneumonia was developed to better understand their interaction. This new murine model successfully mimics the human condition, demonstrating increased tumor growth, metastasis, and alterations in the tumor microenvironment, including elevated tumor-associated macrophages, cancer-associated myofibroblasts, and regulatory T cells, alongside decreased cytotoxic T lymphocytes. Lung cancer comorbid with interstitial pneumonia represents a severe clinical challenge due to diagnostic difficulties and treatment-related complications. The novel murine model offers a valuable tool for future research to develop effective therapies. Dedicated efforts are needed to address this complex pathophysiology to improve patient outcomes.

Interstitial Lung Abnormalities on Unselected Abdominal and Thoracoabdominal CT Scans in 21 118 Patients

Background Interstitial lung abnormalities (ILAs) are incidental CT findings suggesting early interstitial lung disease. However ILA prevalence data are scarce in an unselected routine clinical setting. Purpose To evaluate the prevalence, underreporting rate, and potential clinical impact of ILAs recognizable on either abdominal CT scans or thoracoabdominal CT scans in a routine clinical setting of unselected patients. Materials and Methods Consecutive abdominal or thoracoabdominal CT scans from unselected inpatients and outpatients (age, ≥50 years; without any available prior chest CT and no clinical history of disease against the diagnosis of ILA) from a single-center tertiary hospital between January 2008 and December 2015 were retrospectively reviewed for the presence of ILAs and compared with the original clinical reports from the CT scans. Radiologic progression of ILA was evaluated by comparing consecutive CT points. Multivariable models adjusted for age, sex, race/ethnicity, oncologic disease, and cardiovascular disease were used to assess factors associated with odds of ILAs progression and all-cause and cause-specific mortality. Results Among 21 118 patients (median age, 72 years [IQR, 64-80 years]; 11 028 [52.2%] female patients), ILAs were observed in 362 (1.7%) patients, notably in 222 (1.0%) patients who had fibrotic features at CT. ILAs were recognized in 122 of 9415 (1.3%) and 240 of 11 703 (2.1%) of abdominal and thoracoabdominal CT scans, respectively. Of available original reports for 360 patients, 158 (43.9%) of all ILAs were not originally reported. Traction bronchiectasis index was the CT factor associated with higher odds of ILA progression (odds ratio, 3.47; 95% CI: 1.83, 6.58; P < .001). Fibrotic ILAs had a fourfold higher risk of respiratory-cause mortality (hazard ratio, 4.01; 95% CI: 2.02, 7.92; P < .001) compared with patients without ILAs. Conclusion The prevalence of ILAs was 1.7% in a large, unselected sample of patients who underwent either abdominal or thoracoabdominal CT for various clinical indications. Despite their prognostic significance, 43.9% of ILAs were unreported. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Hata in this issue.

Long-Term Follow-Up of Interstitial Lung Abnormalities in Low-Dose Chest CT in Health Screening: Exploring the Predictors of Clinically Significant Interstitial Lung Diseases Using Artificial Intelligence-Based Quantitative CT Analysis

Purpose

This study examined longitudinal changes in interstitial lung abnormalities (ILAs) and predictors of clinically significant interstitial lung diseases (ILDs) in a screening population with ILAs.

Materials and Methods

We retrieved 36891 low-dose chest CT records from screenings between January 2003 and May 2021. After identifying 101 patients with ILAs, the clinical findings, spirometry results, and initial and follow-up CT findings, including visual and artificial intelligence-based quantitative analyses, were compared between patients diagnosed with ILD (n = 23, 23%) and those who were not (n = 78, 77%). Logistic regression analysis was used to identify significant parameters for the clinical diagnosis of ILD.

Results

Twenty-three patients (n = 23, 23%) were subsequently diagnosed with clinically significant ILDs at follow-up (mean, 8.7 years). Subpleural fibrotic ILAs on initial CT and signs of progression on follow-up CT were common in the ILD group (both p < 0.05). Logistic regression analysis revealed that emerging respiratory symptoms (odds ratio [OR], 5.56; 95% confidence interval [CI], 1.28-24.21; p = 0.022) and progression of ILAs at follow-up chest CT (OR, 4.07; 95% CI, 1.00-16.54; p = 0.050) were significant parameters for clinical diagnosis of ILD.

Conclusion

Clinically significant ILD was subsequently diagnosed in approximately one-quarter of the screened population with ILAs. Emerging respiratory symptoms and progression of ILAs at follow-up chest CT can be predictors of clinically significant ILDs.

Interstitial lung abnormality in COPD is inversely associated with the comorbidity of lung cancer

BACKGROUND

Interstitial lung abnormality (ILA) has been recognized as a pertinent factor in the development and prognosis of various pulmonary conditions. However, its correlation with co-morbidities remains understudied. The current study endeavors to elucidate the association between ILA and both clinical features and co-morbidities in patients with chronic obstructive pulmonary disease (COPD).

METHODS

A retrospective cohort comprising 1131 hospitalized patients diagnosed with COPD was examined in this observational study. Patients were dichotomously classified based on the presence or absence of ILA, and subsequent analyses scrutinized disparities in demographic, clinical, and laboratory profiles, alongside co-morbid conditions, between the two subgroups.

RESULTS

Of the 1131 COPD patients, 165 (14.6%) exhibited ILA. No statistically significant differences were discerned between COPD patients with and without ILA concerning demographic, clinical, or laboratory parameters, except for levels of circulating fibrinogen and procalcitonin. Nevertheless, a notable discrepancy emerged in the prevalence of multiple co-morbidities. Relative to COPD patients devoid of ILA, those presenting with ILA manifested a diminished prevalence of lung cancer (OR = 0.50, 95% CI: 0.30-0.83, p = 0.006), particularly of the lung adenocarcinoma (OR = 0.32, 95% CI: 0.15-0.71, p = 0.005). Additionally, the presence of ILA in COPD was positively associated with heart failure (OR = 1.75, 95% CI: 1.04-3.00, p = 0.040) and cancers other than lung cancer (OR = 2.27, 95% CI: 1.16-4.39, p = 0.012).

CONCLUSION

These findings demonstrate that the presence of ILA is associated with co-morbidities of COPD, particularly lung cancer.

Computed tomography patterns and clinical outcomes of radiation pneumonitis in non-small-cell lung cancer patients

Background

Radiation pneumonitis (RP) is not an uncommon complication in lung cancer patients undergoing radiation therapy (RT) and symptomatic RP can affect their quality of life.

Purpose

To investigate the CT findings of RP in non-small cell lung cancer (NSCLC) patients and their relationship with clinical outcomes.

Materials and methods

We reviewed data from 240 NSCLC patients who underwent RT between 2014 and 2022. CT findings of RP were evaluated for parenchymal abnormalities and distribution, which were then classified into three patterns: localized pneumonia (LP), cryptogenic organizing pneumonia (COP), and acute interstitial pneumonia (AIP). Clinical outcomes of RP were evaluated based on Common Terminology Criteria for Adverse Events (CTCAE) grade.

Results

Of the 153 patients, 135 developed RP. The most common pattern was LP (n = 78), followed by COP (n = 30) and AIP (n = 25). Among the three CT patterns, CTCAE grade and days between the start of RT and the onset of RP (RT-RP days) were statistically significantly different (p < 0.05). The patients with AIP patterns exhibited higher CTCAE grade, and fewer RT-RP days compared to those with non-AIP patterns (p < 0.05). In these patients, lung-to-lung metastasis and underlying interstitial lung abnormality were observed more frequently (p < 0.05). Underlying pulmonary fibrosis, the AIP pattern, and higher CT extent scores were more frequently observed in higher CTCAE grade group (p < 0.001). In multiple regression analysis, age, bilateral distribution, RT-RP days, and CT extent score ≥3 were independent predicting factors for higher CTCAE grade.

Conclusions

RP in NSCLC patients can be classified into LP, COP, and AIP patterns and they exhibit different severities in clinical outcomes.

Air Pollution Exposure and Interstitial Lung Features in SPIROMICS Participants with Chronic Obstructive Pulmonary Disease

Rationale: It is unknown whether air pollution is associated with radiographic features of interstitial lung disease in individuals with chronic obstructive pulmonary disease (COPD). Objectives: To determine whether air pollution increases the prevalence of interstitial lung abnormalities (ILA) or percent high-attenuation areas (HAA) on computed tomography (CT) in individuals with a heavy smoking history and COPD. Methods: We performed a cross-sectional study of SPIROMICS (Subpopulations and Intermediate Outcome Measures in COPD Study), focused on current or former smokers with COPD. Ten-year exposure to particulate matter ⩽2.5 μm in aerodynamic diameter (PM2.5), nitrogen oxides (NOx), nitrogen dioxide (NO2), and ozone before enrollment CT (completed between 2010 and 2015) were estimated with validated spatiotemporal models at residential addresses. We applied adjusted multivariable modified Poisson regression and linear regression to investigate associations between pollution exposure and relative risk (RR) of ILA or increased percent HAA (between -600 and -250 Hounsfield units), respectively. We assessed for effect modification by MUC5B-promoter polymorphism (variant allele carriers GT or TT vs. GG at rs3705950), smoking status, sex, and percent emphysema. Results: Among 1,272 participants with COPD assessed for HAA, 424 were current smokers, and 249 were carriers of the variant MUC5B allele. A total of 519 participants were assessed for ILA. We found no association between pollution exposure and ILA or HAA. Associations between pollutant exposures and risk of ILA were modified by the presence of MUC5B polymorphism (P value interaction term for NOx = 0.04 and PM2.5 = 0.05) and smoking status (P value interaction term for NOx = 0.05; NO2 = 0.01; and ozone = 0.05). With higher exposure to NOx and PM2.5, MUC5B variant carriers had an increased risk of ILA (RR per 26 ppb NOx, 2.41; 95% confidence interval [CI], 0.97-6.0; and RR per 4 μg ⋅ m-3 PM2.5, 1.43; 95% CI, 0.93-2.2, respectively). With higher exposure to NO2, former smokers had an increased risk of ILA (RR per 10 ppb, 1.64; 95% CI, 1.0-2.7). Conclusions: Exposure to ambient air pollution was not associated with interstitial features on CT in this population of heavy smokers with COPD. MUC5B modified the association between pollution and ILA, suggesting that gene-environment interactions may influence prevalence of interstitial lung features in COPD.

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.

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.

Why making smoking cessation a priority for rare interstitial lung disease smokers?

This review aims to discuss the complex relationship between smoking and interstitial lung diseases (ILDs), emphasizing the significant morbidity and mortality associated with these conditions. While the etiology of ILDs remains multifactorial, cigarette smoking emerges as a prominent modifiable risk factor implicated in their pathogenesis and progression. This narrative review will provide insight into smoking-associated interstitial lung diseases and personalised approaches to smoking cessation. Epidemiological studies consistently link smoking to ILDs such as idiopathic pulmonary fibrosis (IPF), respiratory bronchiolitis-associated ILD (RB-ILD), and desquamative interstitial pneumonia (DIP), highlighting the urgent need for comprehensive tobacco cessation strategies. Despite the established benefits of smoking cessation, adherence to cessation programs remains challenging due to nicotine addiction, psychological factors, and social influences. The modest success rates of smoking cessation in ILD patients, emphasises the importance of tailored interventions and ongoing support is needed to overcome barriers and to improve outcomes of quitting smoking in this category of vulnerable patients.

Automated CT quantification of interstitial lung abnormality in patients with resectable stage I non-small cell lung cancer: Prognostic significance

BACKGROUND

In patients with non-small cell lung cancer (NSCLC), interstitial lung abnormalities (ILA) have been linked to mortality and can be identified on computed tomography (CT) scans. In the present study we aimed to evaluate the predictive value of automatically quantified ILA based on the Fleischner Society definition in patients with stage I NSCLC.

METHODS

We retrospectively reviewed 948 patients with pathological stage I NSCLC who underwent pulmonary resection between April 2009 and October 2022. A commercially available deep learning-based automated quantification program for ILA was used to evaluate the preoperative CT data. The Fleischner Society definition, quantitative results, and interdisciplinary discussion led to the division of patients into normal and ILA groups. The sum of the fibrotic and nonfibrotic ILA components constituted the total ILA component and more than 5%.

RESULTS

Of the 948 patients with stage I NSCLC, 99 (10.4%) patients had ILA. Shorter overall survival and recurrence-free survival was associated with the presence of ILA. After controlling for confounding variables, the presence of ILA remained significant for increased risk of death (hazard ratio [HR] = 3.09; 95% confidence interval [CI]: 1.91-5.00; p < 0.001) and the presence of ILA remained significant for increased recurrence (HR = 1.96; 95% CI: 1.16-3.30; p = 0.012).

CONCLUSIONS

The automated CT quantification of ILA, based on the Fleischner Society definition, was significantly linked to poorer survival and recurrence in patients with stage I NSCLC.

Smoking-Related Interstitial Lung Disease and Emphysema

Diagnosis and treatment of patients with smoking-related lung diseases often requires multidisciplinary contributions to optimize care. Imaging plays a key role in characterizing the underlying disease, quantifying its severity, identifying potential complications, and directing management. The primary goal of this article is to provide an overview of the imaging findings and distinguishing features of smoking-related lung diseases, specifically, emphysema/chronic obstructive pulmonary disease, respiratory bronchiolitis-interstitial lung disease, smoking-related interstitial fibrosis, desquamative interstitial pneumonitis, combined pulmonary fibrosis and emphysema, pulmonary Langerhans cell histiocytosis, and E-cigarette or vaping related lung injury.

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 and predictive value of interstitial lung abnormalities and EGFR mutation status in patients with non-small cell lung cancer

BACKGROUND

To determine the predictive value of interstitial lung abnormalities (ILA) for epidermal growth factor receptor (EGFR) mutation status and assess the prognostic significance of EGFR and ILA in patients with non-small cell lung cancer (NSCLC).

METHODS

We reviewed 797 consecutive patients with a histologically proven diagnosis of primary NSCLC from January 2013 to October 2018. Of these, 109 patients with NSCLC were found to have concomitant ILA. Multivariate logistic regression analysis was used to identify the significant clinical and computed tomography (CT) findings in predicting EGFR mutations. Cox proportional hazard models were used to identify significant prognostic factors.

RESULTS

EGFR mutations were identified in 22 of 109 tumors (20.2%). Multivariate analysis showed that the models incorporating clinical, tumor CT and ILA CT features yielded areas under the receiver operating characteristic curve (AUC) values of 0.749, 0.838, and 0.849, respectively. When combining the three models, the independent predictive factors for EGFR mutations were non-fibrotic ILA, female sex, and small tumor size, with an AUC value of 0.920 (95% confidence interval[CI]: 0.861-0.978, p < 0.001). In the multivariate Cox model, EGFR mutations (hazard ratio = 0.169, 95% CI = 0.042-0.675, p = 0.012; 692 days vs. 301 days) were independently associated with extended overall survival compared to the wild-type.

CONCLUSION

Non-fibrotic ILA independently predicts the presence of EGFR mutations, and the presence of EGFR mutations rather than non-fibrotic ILA serves as an independent good prognostic factor for patients with NSCLC.

Pretreatment Interstitial Lung Abnormalities Detected on Abdominal Computed Tomography Scans in Prostate Cancer Patients

OBJECTIVE

Prostate cancer and interstitial lung abnormality (ILA) share similar risk factor, which is men and older age. The purpose of this study was to investigate the prevalence of pretreatment ILA among prostate cancer patients who underwent abdominal computed tomography (CT) within 1 year at their first visit to the urology department. In addition, we aimed to assess the association between pretreatment ILA and long-term survival in prostate cancer patients.

METHODS

This study was conducted in patients who had a first visit for prostate cancer at urology department between 2005 and 2016 and underwent an abdominal CT within 1 year. A thoracic radiologist evaluated the presence of ILA through inspecting the lung base scanned on an abdominal CT. The association between pretreatment ILA and survival was assessed using Kaplan-Meier analysis with log-rank test. Specific survival rates at 12, 36, and 60 months according to the presence of ILA were evaluated using z -test. Cox regression analysis was used to assess the risk factors of mortality.

RESULTS

A total of 173 patients were included (mean age, 70.23 ± 7.98 years). Pretreatment ILA was observed in 10.4% of patients. Patients with ILA were more likely to be older and current smokers. Pretreatment ILA was associated with poor survival ( P < 0.001). Age ≥70 years (hazards ratio [HR], 1.98; 95% confidence interval [CI], 1.24-3.16; P = 0.004), metastatic stage (HR, 2.26; 95% CI, 1.36-3.74; P = 0.002), and ILA (HR, 1.96; 95% CI, 1.06-3.60; P = 0.031) were the independent risk factors of mortality. An ILA (HR, 3.94; 95% CI, 1.78-8.72; P = 0.001) was the only independent risk factor of mortality in localized stage prostate cancer patients.

CONCLUSIONS

This study provides important insights into the unexplored effect of pretreatment ILA in prostate cancer patients. Pretreatment ILAs were observed considerably in the lung bases scanned on the abdominal CT scans among prostate cancer patients. Furthermore, pretreatment ILAs were the risk factor of mortality. Therefore, lung bases should be routinely inspected in the abdominal CT scans of prostate cancer patients. This result may help clinicians in establishing personalized management strategy of prostate cancer patients.

The diagnostic pathway for patients with interstitial lung disease: a mixed-methods study of patients and physicians

OBJECTIVES

The diagnostic process for patients with interstitial lung diseases (ILD) remains complex. The aim of this study was to characterise the diagnostic care pathway and identify barriers and potential solutions to access a timely and accurate ILD diagnosis.

DESIGN

This mixed-method study was comprised of a quantitative chart review, patient and physician surveys and focus groups.

RESULTS

Chart review was completed for 97 patients. Median time from symptom onset to ILD diagnosis was 12.0 (IQR 20.5) months, with 46% diagnosed within 1 year. Time from first computed tomography (CT) scan to respirology referral was 2.4 (IQR 21.2) months. Referrals with a prior CT were triaged sooner than referrals without (1.7±1.6 months vs 3.9±3.3 months, p=0.013, 95% CI 0.48 to 2.94). On patient surveys (n=70), 51% felt that their lung disease was not recognised early enough. Commonly reported challenges to timely diagnosis included delayed presentation to primary care, initial misdiagnoses and long wait-times for specialists. Forty-five per cent of physicians (n=20) identified diagnostic delays, attributed to delayed presentations to primary care (58%), initial misdiagnoses (67%) and delayed chest imaging (75%). Themes from patient and respirologist focus groups included patient-related, healthcare provider-related and system-related factors leading to delays in diagnosis.

CONCLUSIONS

This mixed-methods study identified patient and system-related factors that contribute to diagnostic delays for patients with ILD, with most delays occurring prior to respirology referral. ILD awareness and education, earlier presentation to primary care, expedited access to chest imaging and earlier referral to respirology may expedite diagnosis.

Longitudinal assessment of interstitial lung abnormalities on CT in patients with COPD using artificial intelligence-based segmentation: a prospective observational study

BACKGROUND

Interstitial lung abnormalities (ILAs) on CT may affect the clinical outcomes in patients with chronic obstructive pulmonary disease (COPD), but their quantification remains unestablished. This study examined whether artificial intelligence (AI)-based segmentation could be applied to identify ILAs using two COPD cohorts.

METHODS

ILAs were diagnosed visually based on the Fleischner Society definition. Using an AI-based method, ground-glass opacities, reticulations, and honeycombing were segmented, and their volumes were summed to obtain the percentage ratio of interstitial lung disease-associated volume to total lung volume (ILDvol%). The optimal ILDvol% threshold for ILA detection was determined in cross-sectional data of the discovery and validation cohorts. The 5-year longitudinal changes in ILDvol% were calculated in discovery cohort patients who underwent baseline and follow-up CT scans.

RESULTS

ILAs were found in 32 (14%) and 15 (10%) patients with COPD in the discovery (n = 234) and validation (n = 153) cohorts, respectively. ILDvol% was higher in patients with ILAs than in those without ILA in both cohorts. The optimal ILDvol% threshold in the discovery cohort was 1.203%, and good sensitivity and specificity (93.3% and 76.3%) were confirmed in the validation cohort. 124 patients took follow-up CT scan during 5 ± 1 years. 8 out of 124 patients (7%) developed ILAs. In a multivariable model, an increase in ILDvol% was associated with ILA development after adjusting for age, sex, BMI, and smoking exposure.

CONCLUSION

AI-based CT quantification of ILDvol% may be a reproducible method for identifying and monitoring ILAs in patients with COPD.

Improved pulmonary function and exercise tolerance despite persistent pulmonary fibrosis over 1 year after severe COVID-19 infection

We conducted a prospective single-centre cohort study of 104 multi-ethnic severe COVID-19 survivors from the first wave of the pandemic 15 months after hospitalisation. Of those who were assessed at 4 and 15 months, improvement of ground glass opacities correlated with worsened fibrotic reticulations. Despite a high prevalence of fibrotic patterns (64%), pulmonary function, grip strength, 6 min walk distance and frailty normalised. Overall, dyspnoea, cough and exhaustion did not improve and were not correlated with pulmonary function or radiographic fibrosis at 15 months, suggesting non-respiratory aetiologies. Monitoring persistent, and often subclinical, fibrotic interstitial abnormalities will be needed to determine their potential for future progression.

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.