Interstitial lung abnormalities in a CT lung cancer screening population: prevalence and progression rate

Optimization of a secondary VOI protocol for lung imaging in a clinical CT scanner

We present a solution to meet an unmet clinical need of an in-situ "close look" at a pulmonary nodule or at the margins of a pulmonary cyst revealed by a primary (screening) chest CT while the patient is still in the scanner. We first evaluated options available on current whole-body CT scanners for high resolution screening scans, including ROI reconstruction of the primary scan data and HRCT, but found them to have insufficient SNR in lung tissue or discontinuous slice coverage. Within the capabilities of current clinical CT systems, we opted for the solution of a secondary, volume-of-interest (VOI) protocol where the radiation dose is focused into a short-beam axial scan at the z position of interest, combined with a small-FOV reconstruction at the xy position of interest. The objective of this work was to design a VOI protocol that is optimized for targeted lung imaging in a clinical whole-body CT system. Using a chest phantom containing a lung-mimicking foam insert with a simulated cyst, we identified the appropriate scan mode and optimized both the scan and recon parameters. The VOI protocol yielded 3.2 times the texture amplitude-to-noise ratio in the lung-mimicking foam when compared to the standard chest CT, and 8.4 times the texture difference between the lung mimicking and reference foams. It improved details of the wall of the simulated cyst and better resolution in a line-pair insert. The Effective Dose of the secondary VOI protocol was 42% on average and up to 100% in the worst-case scenario of VOI positioning relative to the standard chest CT. The optimized protocol will be used to obtain detailed CT textures of pulmonary lesions, which are biomarkers for the type and stage of lung diseases.

Preexisting radiological interstitial lung abnormalities are a risk factor for severe radiation pneumonitis in patients with small-cell lung cancer after thoracic radiation therapy

BACKGROUND

Previous studies reported that patients with preexisting radiological interstitial lung abnormalities (ILAs) were more susceptible to developing radiation pneumonitis (RP) after thoracic radiation therapy (TRT). The present study aimed to evaluate the incidence and predictors of RP after TRT in patients with small-cell lung cancer (SCLC) with or without preexisting radiological ILAs.

METHODS

A total of 95 consecutive patients with SCLC between January 2015 and December 2015, who were treated with thoracic intensity-modulated radiation therapy at Shanghai Pulmonary Hospital,Tongji University School of Medicine, were analyzed. The diagnosis of ILAs was reviewed by two experienced thoracic radiologists based on the pretreatment high-resolution computed tomography imaging, such as honeycombing, subpleural reticular opacities, ground-glass opacity, and traction bronchiectasis. Univariate and multivariate analyses were used to assess the correlation of clinical factors, preexisting radiological ILAs, and dose-volume histogram-based dosimetric parameters with RP.

RESULTS

Fifteen (15.8%) patients had preexisting radiological ILAs. The incidence of ≥ grade 2 and 3 RP at 1 year was 27.1% and 12.7% in the entire cohort, respectively. Preexisting radiological ILAs were associated with an increased risk of ≥grade 2 RP (50.0% in ILAs + vs 23.3% in ILAs-, P = 0.017) and ≥ grade 3 RP (35.8% in ILAs + vs 8.9% in ILAs-, P = 0.005) at 1 year. Preexisting radiological ILAs and smoking history (≥40 pack-years of smoking) were significant predictors of ≥grade 3 RP in multivariate analysis (P = 0.023 and 0.012, respectively).

CONCLUSIONS

Preexisting radiological ILAs and smoking history (≥40 pack-years of smoking) are associated with an increased risk of ≥grade 3 RP after TRT in patients with SCLC.

Personalised medicine in interstitial lung diseases

Interstitial lung diseases in general, and idiopathic pulmonary fibrosis in particular, are complex disorders with multiple pathogenetic pathways, various disease behaviour profiles and different responses to treatment, all facets that make personalised medicine a highly attractive concept. Personalised medicine is aimed at describing distinct disease subsets taking into account individual lifestyle, environmental exposures, genetic profiles and molecular pathways. The cornerstone of personalised medicine is the identification of biomarkers that can be used to inform diagnosis, prognosis and treatment stratification. At present, no data exist validating a personalised approach in individual diseases. However, the importance of the goal amply justifies the characterisation of genotype and pathway signatures with a view to refining prognostic evaluation and trial design, with the ultimate aim of selecting treatments according to profiles in individual patients.

Interstitial lung abnormality is prevalent and associated with worse outcome in patients undergoing transcatheter aortic valve replacement

BACKGROUND

Interstitial lung abnormality (ILA) is found in 5-10% of the general population and is associated with increased mortality risk. Risk factors for ILA, including advanced age and smoking history also increase the risk for aortic stenosis (AS). Transcatheter aortic valve replacement (TAVR) has become an increasingly utilized intervention for patients with severe AS, and requires a high-resolution computed tomography (HRCT) of the chest to assess aortic valve dimensions.

OBJECTIVES

To determine the prevalence and clinical significance of ILA on HRCT performed in patients referred for TAVR.

METHODS

Consecutive pre-TAVR HRCTs performed over a 5-year period were reviewed. ILA was defined as bilateral, nondependent reticular opacities. All-cause mortality among TAVR recipients was compared between ILA cases and non-ILA controls matched 2:1 by age and gender using Cox proportional hazards regression and the Kaplan Meier estimator.

RESULTS

Of 623 HRCTs screened, ILA was detected in 92 (14.7%), including 62 patients that underwent TAVR. Among ILA cases, 17 (27.4%) had a typical or probable usual interstitial pneumonia pattern, suggesting a diagnosis of idiopathic pulmonary fibrosis. Survival was worse in ILA cases compared to non-ILA controls (p = 0.008) and ILA was an independent predictor of mortality after multivariable adjustment (HR 3.29, 95% CI 1.34-8.08; p = 0.009).

CONCLUSIONS

ILA is a common finding among patients with severe AS and is associated with increased mortality in those undergoing TAVR. Further research is needed to elucidate the biology underpinning this observation and determine whether ILA evaluation and risk stratification modulates this mortality risk.

Current Concepts in Pathogenesis, Diagnosis, and Management of Smoking-Related Interstitial Lung Diseases

Tobacco exposure results in various changes to the airways and lung parenchyma. Although emphysema represents the more common injury pattern, in some individuals, cigarette smoke injures alveolar epithelial cells and other lung cells, resulting in diffuse infiltrates and parenchymal fibrosis. Smoking can trigger interstitial injury patterns mediated via recruitment and inappropriate persistence of myeloid and other immune cells, including eosinophils. As our understanding of the role of cigarette smoke constituents in triggering lung injury continues to evolve, so does our recognition of the spectrum of smoking-related interstitial lung changes. Although respiratory bronchiolitis-interstitial lung disease, desquamative interstitial pneumonia, pulmonary Langerhans cell histiocytosis, and acute eosinophilic pneumonia have a well-established association with tobacco use, its role and impact on idiopathic pulmonary fibrosis, combined pulmonary fibrosis and emphysema, and connective tissue disease-related interstitial lung diseases is still ambiguous. Smoking-related interstitial fibrosis is a relatively newly appreciated entity with distinct histopathologic features but with unclear clinical ramifications. Increased implementation of lung cancer screening programs and utilization of CT scans in thoracic imaging have also resulted in increased identification of "incidental" or "subclinical" interstitial lung changes in smokers, the ensuing impact of which remains to be studied.

High-Attenuation Areas on Chest Computed Tomography and Clinical Respiratory Outcomes in Community-Dwelling Adults

RATIONALE

Areas of increased lung attenuation visualized by computed tomography are associated with all-cause mortality in the general population. It is uncertain whether this association is attributable to interstitial lung disease (ILD).

OBJECTIVES

To determine whether high-attenuation areas are associated with the risk of ILD hospitalization and mortality in the general population.

METHODS

We performed a cohort study of 6,808 adults aged 45-84 years sampled from six communities in the United States. High-attenuation areas were defined as the percentage of imaged lung volume with attenuation values between -600 and -250 Hounsfield units. An adjudication panel determined ILD hospitalization and death.

MEASUREMENTS AND MAIN RESULTS

After adjudication, 52 participants had a diagnosis of ILD during 75,232 person-years (median, 12.2 yr) of follow-up. There were 48 hospitalizations attributable to ILD (crude rate, 6.4 per 10,000 person-years). Twenty participants died as a result of ILD (crude rate, 2.7 per 10,000 person-years). High-attenuation areas were associated with an increased rate of ILD hospitalization (adjusted hazard ratio, 2.6 per 1-SD increment in high-attenuation areas; 95% confidence interval, 1.9-3.5; P < 0.001), a finding that was stronger among men, African Americans, and Hispanics. High-attenuation areas were also associated with an increased rate of ILD-specific death (adjusted hazard ratio, 2.3; 95% confidence interval, 1.7-3.0; P < 0.001). Our findings were consistent among both smokers and nonsmokers.

CONCLUSIONS

Areas of increased lung attenuation are a novel risk factor for ILD hospitalization and mortality. Measurement of high-attenuation areas by screening and diagnostic computed tomography may be warranted in at-risk adults.

Idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive lung disease characterized by progressive lung scarring and the histological picture of usual interstitial pneumonia (UIP). It is associated with increasing cough and dyspnoea and impaired quality of life. IPF affects ∼3 million people worldwide, with incidence increasing dramatically with age. The diagnostic approach includes the exclusion of other interstitial lung diseases or overlapping conditions and depends on the identification of the UIP pattern, usually with high-resolution CT; lung biopsy might be required in some patients. The UIP pattern is predominantly bilateral, peripheral and with a basal distribution of reticular changes associated with traction bronchiectasis and clusters of subpleural cystic airspaces. The biological processes underlying IPF are thought to reflect an aberrant reparative response to repetitive alveolar epithelial injury in a genetically susceptible ageing individual, although many questions remain on how to define susceptibility. Substantial progress has been made in the understanding of the clinical management of IPF, with the availability of two pharmacotherapeutic agents, pirfenidone and nintedanib, that decrease physiological progression and likely improve progression-free survival. Current efforts are directed at identifying IPF early, potentially relying on combinations of biomarkers that include circulating factors, demographics and imaging data.

The Objective Identification and Quantification of Interstitial Lung Abnormalities in Smokers

RATIONALE AND OBJECTIVES

Previous investigation suggests that visually detected interstitial changes in the lung parenchyma of smokers are highly clinically relevant and predict outcomes, including death. Visual subjective analysis to detect these changes is time-consuming, insensitive to subtle changes, and requires training to enhance reproducibility. Objective detection of such changes could provide a method of disease identification without these limitations. The goal of this study was to develop and test a fully automated image processing tool to objectively identify radiographic features associated with interstitial abnormalities in the computed tomography scans of a large cohort of smokers.

MATERIALS AND METHODS

An automated tool that uses local histogram analysis combined with distance from the pleural surface was used to detect radiographic features consistent with interstitial lung abnormalities in computed tomography scans from 2257 individuals from the Genetic Epidemiology of COPD study, a longitudinal observational study of smokers. The sensitivity and specificity of this tool was determined based on its ability to detect the visually identified presence of these abnormalities.

RESULTS

The tool had a sensitivity of 87.8% and a specificity of 57.5% for the detection of interstitial lung abnormalities, with a c-statistic of 0.82, and was 100% sensitive and 56.7% specific for the detection of the visual subtype of interstitial abnormalities called fibrotic parenchymal abnormalities, with a c-statistic of 0.89.

CONCLUSIONS

In smokers, a fully automated image processing tool is able to identify those individuals who have interstitial lung abnormalities with moderate sensitivity and specificity.

Development and Progression of Interstitial Lung Abnormalities in the Framingham Heart Study

RATIONALE

The relationship between the development and/or progression of interstitial lung abnormalities (ILA) and clinical outcomes has not been previously investigated.

OBJECTIVES

To determine the risk factors for, and the clinical consequences of, having ILA progression in participants from the Framingham Heart Study.

METHODS

ILA were assessed in 1,867 participants who had serial chest computed tomography (CT) scans approximately 6 years apart. Mixed effect regression (and Cox) models were used to assess the association between ILA progression and pulmonary function decline (and mortality).

MEASUREMENTS AND MAIN RESULTS

During the follow-up period 660 (35%) participants did not have ILA on either CT scan, 37 (2%) had stable to improving ILA, and 118 (6%) had ILA with progression (the remaining participants without ILA were noted to be indeterminate on at least one CT scan). Increasing age and increasing copies of the MUC5B promoter polymorphism were associated with ILA progression. After adjustment for covariates, ILA progression was associated with a greater FVC decline when compared with participants without ILA (20 ml; SE, ±6 ml; P = 0.0005) and with those with ILA without progression (25 ml; SE, ±11 ml; P = 0.03). Over a median follow-up time of approximately 4 years, after adjustment, ILA progression was associated with an increase in the risk of death (hazard ratio, 3.9; 95% confidence interval, 1.3-10.9; P = 0.01) when compared with those without ILA.

CONCLUSIONS

These findings demonstrate that ILA progression in the Framingham Heart Study is associated with an increased rate of pulmonary function decline and increased risk of death.

Impact of Pretreatment Interstitial Lung Disease on Radiation Pneumonitis and Survival in Patients Treated With Lung Stereotactic Body Radiation Therapy (SBRT)

INTRODUCTION

The purpose of this study was to determine the impact of interstitial lung disease (ILD) on radiation pneumonitis (RP) and overall survival (OS) in lung stereotactic body radiation therapy (SBRT).

METHODS

Patients treated with lung SBRT from 2004 to 2015 were included. Pretreatment computed tomography scans were reviewed and classified for interstitial changes by thoracic radiologists using American Thoracic Society guidelines and Washko and Kazerooni scores. RP was scored prospectively using Common Terminology Criteria for Adverse Events, version 3.0. Pretreatment imaging characteristics, clinical variables, and dosimetry were assessed by univariate (UVA) and multivariate analysis (MVA). OS was assessed by the log-rank test, and the impact of ILD on OS was assessed by Cox regression.

RESULTS

Of the 537 patients assessed, 39 had interstitial changes (13 usual interstitial pneumonia [UIP], 24 possible UIP, and 2 inconsistent with UIP). RP was significantly higher in patients with ILD than in patients without ILD (grade ≥ 2, 20.5% vs. 5.8%; P < .01; grade ≥ 3, 10.3% vs. 1.0%; P < .01). Two of 3 grade 5 RP had imaging features of ILD. On UVA, ILD, Washko score, lung parameters performance status, and dose were significant predictors of grade ≥ 2 RP. On MVA, ILD (odds ratio, 5.81; 95% confidence interval, 2.28-14.83; P < .01) and mean lung dose (odds ratio, 1.40; 95% confidence interval, 1.14-1.71; P < .01) were predictors of RP. ILD did not significantly affect OS on UVA or MVA. Median survival was 27.4 months in the ILD cohort and 34.8 in the ILD-negative cohort (P = .17).

DISCUSSION

ILD is a significant risk factor for RP in patients treated with lung SBRT. Computed tomography scans should be reviewed for evidence of ILD prior to SBRT.

Diffuse parenchymal lung disease

Between September 2015 and August 2016 there were >1500 publications in the field of diffuse parenchymal lung diseases (DPLDs). For the Clinical Year in Review session at the European Respiratory Society Congress that was held in London, UK, in September 2016, we selected only five articles. This selection, made from the enormous number of published papers, does not include all the relevant studies that will significantly impact our knowledge in the field of DPLDs in the near future. This review article provides our personal view on the following topics: early diagnosis of idiopathic pulmonary fibrosis, current knowledge on the multidisciplinary team diagnosis of DPLDs and the diagnostic role of transbronchial cryobiopsy in this diagnostic setting, insights on the new entity of interstitial pneumonia with autoimmune features, and new therapeutic approaches for scleroderma-related interstitial lung disease.

Spectrum of Smoking-related Lung Diseases: Imaging Review and Update

There is increased awareness of smoking-related lung diseases other than lung cancer and chronic obstructive pulmonary disease. Concurrently, there is general acceptance that there is difficulty in establishing a specific diagnosis of smoking-related interstitial lung disease (ILD), as many patients may not undergo biopsy to facilitate a specific histopathologic diagnosis. Cases that do proceed to biopsy may demonstrate multiple abnormalities, and histologic overlap between different disease processes may confound the picture. This review outlines the key aspects of smoking-related lung disease, including entities secondary to smoking-related lung inflammation such as respiratory bronchiolitis-ILD, desquamative idiopathic pneumonia, and pulmonary Langerhans cell histiocytosis, as well as chronic fibrosing lung diseases strongly associated with cigarette smoke including idiopathic pulmonary fibrosis, combined pulmonary fibrosis and emphysema, nonspecific interstitial pneumonia, and rheumatoid arthritis-ILD. The focus will be on incorporation of clinical findings, key pulmonary function testing parameters, high-resolution computer tomography (HRCT) findings, and pathologic correlates in refining the differential diagnosis and differentiating between the various entities.

An analysis of the clinical features of lung cancer in patients with connective tissue diseases

BACKGROUND

Patients with connective tissue diseases (CTDs) are at increased risk for lung cancer (LC); interstitial lung disease (ILD) is a common form of organ dysfunction in cases of CTD. However, the influence of ILD on the treatment and prognosis in LC patients with CTD is unclear.

METHODS

Between January 2010 and December 2014, 27 patients among all patients with CTD at our institution were diagnosed with primary LC. We retrospectively analyzed the clinical features, treatment modalities, and outcomes of these patients, and evaluated the potential prognostic factors. Forty-four LC patients without CTD were also analyzed as a control cohort.

RESULTS

LC patients with CTD had a significantly higher incidence of ILD as a complication compared with those without CTD (52% and 14%, respectively). CTD-associated ILD (CTD-ILD) at diagnosis was associated with significantly worse survival in LC patients with CTD. Multivariate analysis demonstrated that the complication of CTD-ILD was an independent poor prognostic factor in LC patients with CTD. The incidence of acute exacerbation (AE) of CTD-ILD was 21% among LC patients with CTD, and all of these patients died despite intensive treatment including high-dose corticosteroids. The restrictions in curative therapy for LC due to the presence of ILD and AE of CTD-ILD were thought to be the major reasons for the poor outcome.

CONCLUSIONS

LC patients with CTD had a high prevalence of ILD, and the presence of CTD-ILD was significantly associated with poor prognosis.

The diagnosis of idiopathic pulmonary fibrosis: current and future approaches

With the recent development of two effective treatments for patients with idiopathic pulmonary fibrosis, an accurate diagnosis is crucial. The traditional approach to diagnosis emphasises the importance of thorough clinical and laboratory evaluations to exclude secondary causes of disease. High-resolution CT is a critical initial diagnostic test and acts as a tool to identify patients who should undergo surgical lung biopsy to secure a definitive histological diagnosis of usual interstitial pneumonia pattern. This diagnostic approach faces several challenges. Many patients with suspected idiopathic pulmonary fibrosis present with atypical high-resolution CT characteristics but are unfit for surgical lung biopsy, therefore preventing a confident diagnosis. The state of the art suggests an iterative, multidisciplinary process that incorporates available clinical, laboratory, imaging, and histological features. Recent research has explored genomic techniques to molecularly phenotype patients with interstitial lung disease. In the future, clinicians will probably use blood-specific or lung-specific molecular markers in combination with other clinical, physiological, and imaging features to enhance diagnostic efforts, refine prognostic recommendations, and influence the initial or subsequent treatment options. There is an urgent and increasing need for well designed, large, prospective studies measuring the effect of different diagnostic approaches. Ultimately, this will help to inform the development of guidelines and tailor clinical practice for the benefit of patients.

Potential Metabolic Biomarkers to Identify Interstitial Lung Abnormalities

Determining sensitive biomarkers in the peripheral blood to identify interstitial lung abnormalities (ILAs) is essential for the simple early diagnosis of ILAs. This study aimed to determine serum metabolic biomarkers of ILAs and the corresponding pathogenesis. Three groups of subjects undergoing health screening, including healthy subjects, subjects with ILAs, and subjects who were healthy initially and with ILAs one year later (Healthy→ILAs), were recruited for this study. The metabolic profiles of all of the subjects’ serum were analyzed by liquid chromatography quadruple time-of-flight mass spectrometry. The metabolic characteristics of the ILAs subjects were discovered, and the corresponding biomarkers were predicted. The metabolomic data from the Healthy→ILAs subjects were collected for further verification. The results indicated that five serum metabolite alterations (up-regulated phosphatidylcholine, phosphatidic acid, betaine aldehyde and phosphatidylethanolamine, as well as down-regulated 1-acylglycerophosphocholine) were sensitive and reliable biomarkers for identifying ILAs. Perturbation of the corresponding biological pathways (RhoA signaling, mTOR/P70S6K signaling and phospholipase C signaling) might be at least partially responsible for the pathogenesis of ILAs. This study may provide a good template for determining the early diagnostic markers of subclinical disease status and for obtaining a better understanding of their pathogenesis.

The Value of a Multidisciplinary Approach to the Diagnosis of Usual Interstitial Pneumonitis and Idiopathic Pulmonary Fibrosis: Radiology, Pathology, and Clinical Correlation

OBJECTIVE

Multidisciplinary discussion is essential in establishing the diagnosis of idiopathic pulmonary fibrosis (IPF) and in determining prognosis.

CONCLUSION

The CT and histopathologic correlate for IPF is usual interstitial pneumonitis (UIP). If a high-confidence diagnosis of UIP is made on CT, IPF is almost always the diagnosis, obviating lung biopsy. If a confident diagnosis of UIP cannot be made on CT, further assessment with lung biopsy and multidisciplinary discussion are often necessary to achieve a confident final diagnosis.

Are interstitial lung abnormalities associated with COPD? A nested case-control study

Purpose

In this study, we tested the association between COPD and interstitial lung abnormality (ILA), notably in relation to the presence of computed tomography (CT) signs of lung fibrosis.

Patients and methods

COPD cases were selected from participants undergoing lung cancer screening (Multicentric Italian Lung Detection trial) for airflow obstruction (n=311/2,303, 13.5%) and 146 consecutive patients with clinical COPD. In all, 457 COPD cases were selected and classified according to the stages of Global Initiative for Chronic Obstructive Lung Disease. A nested matching (case:control = 1:2) according to age, sex, and smoking history was operated between each COPD case and two control subjects from Multicentric Italian Lung Detection trial without airflow obstruction. Low-dose CT scans of COPD cases and controls were reviewed for the presence of ILA, which were classified into definite or indeterminate according to the presence of signs of lung fibrosis.

Results

The frequency of definite ILA was similar between COPD cases and controls (P=0.2), independent of the presence of signs of lung fibrosis (P=0.07). Combined definite and indeterminate ILA was homogeneously distributed across Global Initiative for Chronic Obstructive Lung Disease stages (P=0.6). Definite ILA was directly associated with current smoker status (odds ratio [OR] 4.05, 95% confidence interval [CI]: 2.2–7.4) and increasing pack-years (OR 1.01, 95% CI: 1–1.02). Subjects with any fibrotic ILA were more likely to be older (OR 1.17, 95% CI: 1.10–1.25) and male (OR 8.58, 95% CI: 1.58–68.9).

Conclusion

There was no association between COPD and definite ILA. However, low-dose CT signs of lung fibrosis were also observed in COPD, and their clinical relevance is yet to be determined.

Risk factors assessment and risk prediction models in lung cancer screening candidates

From February 2015, low-dose computed tomography (LDCT) screening entered the armamentarium of diagnostic tools broadly available to individuals at high-risk of developing lung cancer. While a huge number of pulmonary nodules are identified, only a small fraction turns out to be early lung cancers. The majority of them constitute a variety of benign lesions. Although it entails a burden of the diagnostic work-up, the undisputable benefit emerges from: (I) lung cancer diagnosis at earlier stages (stage shift); (II) additional findings enabling the implementation of a preventive action beyond the realm of thoracic oncology. This review presents how to utilize the risk factors from distinct categories such as epidemiology, radiology and biomarkers to target the fraction of population, which may benefit most from the introduced screening modality.

Interstitial changes in asthma-COPD overlap syndrome

INTRODUCTION

Asthma-COPD overlap syndrome (ACOS) is the widely recognized syndrome of asthma and COPD coexisting together. Cigarette smoking is a known risk factor for ACOS and is reported to be associated with interstitial lung diseases (ILDs). Subclinical ILDs have been frequently detected in smokers' lungs by radiological and pathological examinations. This finding raises the possibility that unrecognized mild interstitial changes take place in lungs with ACOS.

OBJECTIVES

We sought to determine whether interstitial changes were present in the lungs of patients with ACOS and to characterize the clinical features of ACOS with interstitial changes.

METHODS

Thirty patients with ACOS were enrolled in the study (26 men and 4 women, mean age 70.1 years). Interstitial changes in the lungs were estimated by high-resolution computed tomography (HRCT). Clinical findings and airway wall thickness on HRCT were assessed retrospectively and compared between ACOS patients with and without interstitial changes.

RESULTS

Interstitial changes were found in seven patients (23.3%) with ACOS who had HRCT. The age and smoking amount were significantly higher in ACOS with interstitial changes than in ACOS without interstitial changes. ACOS with interstitial changes tended to have a higher rate of fungal sensitisation. Multivariate analysis showed pack-years were significantly related to the presence of interstitial changes. Airway walls assessed by HRCT were significantly thicker in ACOS with interstitial changes than in ACOS without interstitial changes.

CONCLUSIONS

The ACOS patients with interstitial changes were heavier smokers and had thicker airway walls on HRCT compared to the ACOS patients without interstitial changes.

Association Between Interstitial Lung Abnormalities and All-Cause Mortality

IMPORTANCE

Interstitial lung abnormalities have been associated with lower 6-minute walk distance, diffusion capacity for carbon monoxide, and total lung capacity. However, to our knowledge, an association with mortality has not been previously investigated.

OBJECTIVE

To investigate whether interstitial lung abnormalities are associated with increased mortality.

DESIGN, SETTING, AND POPULATION

Prospective cohort studies of 2633 participants from the FHS (Framingham Heart Study; computed tomographic [CT] scans obtained September 2008-March 2011), 5320 from the AGES-Reykjavik Study (Age Gene/Environment Susceptibility; recruited January 2002-February 2006), 2068 from the COPDGene Study (Chronic Obstructive Pulmonary Disease; recruited November 2007-April 2010), and 1670 from ECLIPSE (Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints; between December 2005-December 2006).

EXPOSURES

Interstitial lung abnormality status as determined by chest CT evaluation.

MAIN OUTCOMES AND MEASURES

All-cause mortality over an approximate 3- to 9-year median follow-up time. Cause-of-death information was also examined in the AGES-Reykjavik cohort.

RESULTS

Interstitial lung abnormalities were present in 177 (7%) of the 2633 participants from FHS, 378 (7%) of 5320 from AGES-Reykjavik, 156 (8%) of 2068 from COPDGene, and in 157 (9%) of 1670 from ECLIPSE. Over median follow-up times of approximately 3 to 9 years, there were more deaths (and a greater absolute rate of mortality) among participants with interstitial lung abnormalities when compared with those who did not have interstitial lung abnormalities in the following cohorts: 7% vs 1% in FHS (6% difference [95% CI, 2% to 10%]), 56% vs 33% in AGES-Reykjavik (23% difference [95% CI, 18% to 28%]), and 11% vs 5% in ECLIPSE (6% difference [95% CI, 1% to 11%]). After adjustment for covariates, interstitial lung abnormalities were associated with a higher risk of death in the FHS (hazard ratio [HR], 2.7 [95% CI, 1.1 to 6.5]; P = .03), AGES-Reykjavik (HR, 1.3 [95% CI, 1.2 to 1.4]; P < .001), COPDGene (HR, 1.8 [95% CI, 1.1 to 2.8]; P = .01), and ECLIPSE (HR, 1.4 [95% CI, 1.1 to 2.0]; P = .02) cohorts. In the AGES-Reykjavik cohort, the higher rate of mortality could be explained by a higher rate of death due to respiratory disease, specifically pulmonary fibrosis.

CONCLUSIONS AND RELEVANCE

In 4 separate research cohorts, interstitial lung abnormalities were associated with a greater risk of all-cause mortality. The clinical implications of this association require further investigation.

Normal thymus in adults: appearance on CT and associations with age, sex, BMI and smoking

OBJECTIVE

To investigate CT appearance and size of the thymus in association with participant characteristics.

MATERIALS AND METHODS

2540 supposedly healthy participants (mean age 58.9 years, 51 % female) were evaluated for the CT appearance of thymic glands with four-point scores (according to the ratio of fat and soft tissue), size and morphology. These were correlated with participants' age, sex, BMI and smoking history.

RESULTS

Of 2540 participants, 1869 (74 %) showed complete fatty replacement of the thymus (Score 0), 463 (18 %) predominantly fatty attenuation (Score 1), 172 (7 %) half fatty and half soft-tissue attenuation (Score 2) and 36 (1 %) solid thymic gland with predominantly soft-tissue attenuation (Score 3). Female participants showed less fatty degeneration of the thymus with higher thymic scores within age 40-69 years (P < 0.001). Participants with lower thymic scores showed higher BMI (P < 0.001) and were more likely to be former smokers (P < 0.001) with higher pack-years (P = 0.04).

CONCLUSIONS

Visual assessment with four-point thymic scores revealed a sex difference in the fatty degeneration of the thymus with age. Women show significantly higher thymic scores, suggesting less fat content of the thymus, during age 40-69 years. Cigarette smoking and high BMI are associated with advanced fatty replacement of the thymus.

KEY POINTS

74% of participants (mean age 58.9 years) demonstrated complete fatty thymus. Women show less fatty thymus compared to men at ages 40-69 years. Smoking and high BMI are associated with advanced fatty degeneration in thymus.

Role of imaging in the diagnosis of diffuse and interstitial lung diseases

PURPOSE OF REVIEW

This review aims to provide a literature update focused on the role of imaging in the diagnosis, prognosis and quantification of interstitial lung diseases (ILDs). Special emphasis is given in the management of atypical cases and in the multidisciplinary team approach in reaching the diagnosis of the various ILDs.

RECENT FINDINGS

Accumulated knowledge on imaging has increased the accuracy of differential diagnosis in atypical cases, in overlap of findings and in secondary as opposed to idiopathic ILDs. There is increasing awareness about interstitial lung abnormalities in smokers' lungs from lung cancer screening and indirect evidence of linkage of fibrosis and smoking. Improvement in radiologic-pathologic correlation reveals less typical high-resolution computed tomography patterns to be predictive of pulmonary fibrosis. Major diagnostic criteria such as honeycombing may be hampered by the coexistence of emphysema. High-resolution computed tomography may predict clinical outcome and survival of patients in ILDs and is a decision maker in the multidisciplinary approach of diagnosis.

SUMMARY

High-resolution computed tomography plays a crucial role in the diagnosis, prognosis, quantification and monitoring of ILDs. It provides a definite noninvasive diagnosis in typical findings and helps in reaching the most accurate diagnosis in a multidisciplinary discussion in equivocal cases.

A comparison of visual and quantitative methods to identify interstitial lung abnormalities

Background

Evidence suggests that individuals with interstitial lung abnormalities (ILA) on a chest computed tomogram (CT) may have an increased risk to develop a clinically significant interstitial lung disease (ILD). Although methods used to identify individuals with ILA on chest CT have included both automated quantitative and qualitative visual inspection methods, there has been not direct comparison between these two methods. To investigate this relationship, we created lung density metrics and compared these to visual assessments of ILA.

Methods

To provide a comparison between ILA detection methods based on visual assessment we generated measures of high attenuation areas (HAAs, defined by attenuation values between −600 and −250 Hounsfield Units) in >4500 participants from both the COPDGene and Framingham Heart studies (FHS). Linear and logistic regressions were used for analyses.

Results

Increased measures of HAAs (in ≥10 % of the lung) were significantly associated with ILA defined by visual inspection in both cohorts (P < 0.0001); however, the positive predictive values were not very high (19 % in COPDGene and 13 % in the FHS). In COPDGene, the association between HAAs and ILA defined by visual assessment were modified by the percentage of emphysema and body mass index. Although increased HAAs were associated with reductions in total lung capacity in both cohorts, there was no evidence for an association between measurement of HAAs and MUC5B promoter genotype in the FHS.

Conclusion

Our findings demonstrate that increased measures of lung density may be helpful in determining the severity of lung volume reduction, but alone, are not strongly predictive of ILA defined by visual assessment. Moreover, HAAs were not associated with MUC5B promoter genotype.

American Thoracic Society-European Respiratory Society Classification of the Idiopathic Interstitial Pneumonias: Advances in Knowledge since 2002

In the updated American Thoracic Society-European Respiratory Society classification of the idiopathic interstitial pneumonias (IIPs), the major entities have been preserved and grouped into (a) "chronic fibrosing IIPs" (idiopathic pulmonary fibrosis and idiopathic nonspecific interstitial pneumonia), (b) "smoking-related IIPs" (respiratory bronchiolitis-associated interstitial lung disease and desquamative interstitial pneumonia), (c) "acute or subacute IIPs" (cryptogenic organizing pneumonia and acute interstitial pneumonia), and (d) "rare IIPs" (lymphoid interstitial pneumonia and idiopathic pleuroparenchymal fibroelastosis). Furthermore, it has been acknowledged that a final diagnosis is not always achievable, and the category "unclassifiable IIP" has been proposed. The diagnostic interpretation of the IIPs is often challenging because other diseases with a known etiology (most notably, connective tissue disease and hypersensitivity pneumonitis) may show similar morphologic patterns. Indeed, more emphasis has been given to the integration of clinical, computed tomographic (CT), and pathologic findings for multidisciplinary diagnosis. Typical CT-based morphologic patterns are associated with the IIPs, and radiologists play an important role in diagnosis and characterization. Optimal CT quality and a systematic approach are both pivotal for evaluation of IIP. Interobserver variation for the various patterns encountered in the IIPs is an issue. It is important for radiologists to understand the longitudinal behavior of IIPs at serial CT examinations, especially for providing a framework for cases that are unclassifiable or in which a histologic diagnosis cannot be obtained.

Smoking and interstitial lung diseases

For many years has been well known that smoking could cause lung damage. Chronic obstructive pulmonary disease and lung cancer have been the two most common smoking-related lung diseases. In the recent years, attention has also focused on the role of smoking in the development of interstitial lung diseases (ILDs). Indeed, there are three diseases, namely respiratory bronchiolitis-associated ILD, desquamative interstitial pneumonia and pulmonary Langerhans cell histiocytosis, that are currently considered aetiologically linked to smoking and a few others which are more likely to develop in smokers. Here, we aim to focus on the most recent findings regarding the role of smoking in the pathogenesis and clinical behaviour of ILDs.

Smoking is implicated in the pathogenesis and clinical behaviour of interstitial lung diseasehttp://ow.ly/PYLcT

Smoking-related idiopathic interstitial pneumonia: A review

For many years, cigarette smoking has been considered as the leading cause of chronic obstructive pulmonary disease and lung cancer. Recently, however, it has also been associated with the development of diffuse interstitial lung diseases. In the latest classification of the major idiopathic interstitial pneumonias (IIP), the term smoking-related IIP has been introduced, including two entities, namely desquamative interstitial pneumonia (DIP) and respiratory bronchiolitis-interstitial lung disease (RB-ILD). Other entities in which smoking has a definite or suggested role include pulmonary Langerhan's cell histiocytosis, smoking-related interstitial fibrosis, combined pulmonary fibrosis and emphysema syndrome and idiopathic pulmonary fibrosis. In this review, we will focus on the mechanisms of smoking-related lung damage and on the clinical aspects of these disorders with the exception of idiopathic pulmonary fibrosis, which will be reviewed elsewhere in this review series.

Molecular classification of idiopathic pulmonary fibrosis: personalized medicine, genetics and biomarkers

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive fibrotic lung disease associated with high morbidity and poor survival. Characterized by substantial disease heterogeneity, the diagnostic considerations, clinical course and treatment response in individual patients can be variable. In the past decade, with the advent of high-throughput proteomic and genomic technologies, our understanding of the pathogenesis of IPF has greatly improved and has led to the recognition of novel treatment targets and numerous putative biomarkers. Molecular biomarkers with mechanistic plausibility are highly desired in IPF, where they have the potential to accelerate drug development, facilitate early detection in susceptible individuals, improve prognostic accuracy and inform treatment recommendations. Although the search for candidate biomarkers remains in its infancy, attractive targets such as MUC5B and MPP7 have already been validated in large cohorts and have demonstrated their potential to improve clinical predictors beyond that of routine clinical practices. The discovery and implementation of future biomarkers will face many challenges, but with strong collaborative efforts among scientists, clinicians and the industry the ultimate goal of personalized medicine may be realized.

CT-Definable Subtypes of Chronic Obstructive Pulmonary Disease: A Statement of the Fleischner Society

The purpose of this statement is to describe and define the phenotypic abnormalities that can be identified on visual and quantitative evaluation of computed tomographic (CT) images in subjects with chronic obstructive pulmonary disease (COPD), with the goal of contributing to a personalized approach to the treatment of patients with COPD. Quantitative CT is useful for identifying and sequentially evaluating the extent of emphysematous lung destruction, changes in airway walls, and expiratory air trapping. However, visual assessment of CT scans remains important to describe patterns of altered lung structure in COPD. The classification system proposed and illustrated in this article provides a structured approach to visual and quantitative assessment of COPD. Emphysema is classified as centrilobular (subclassified as trace, mild, moderate, confluent, and advanced destructive emphysema), panlobular, and paraseptal (subclassified as mild or substantial). Additional important visual features include airway wall thickening, inflammatory small airways disease, tracheal abnormalities, interstitial lung abnormalities, pulmonary arterial enlargement, and bronchiectasis.