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

Clinical utility, reproducibility, and radiologist acceptance of ILD-RADS

PURPOSE

To investigate the clinical utility, reproducibility, and radiologists' acceptance of the Interstitial Lung Disease Imaging-Reporting and Data System (ILD-RADS).

METHOD

In this single-institutional retrospective study, three radiologists independently reviewed the chest high-resolution CT (HRCT) scans of 111 consecutive patients diagnosed with ILDs. They assessed the HRCT pulmonary features using the ILD-RADS template and assigned an ILD-RADS category (1-4) to each scan based on the identified imaging pattern. Patients were classified into idiopathic pulmonary fibrosis (IPF) (n = 14) and non-IPF ILD (n = 97) groups based on clinical diagnoses determined by multidisciplinary discussion. Association between ILD-RADS categories and clinical diagnoses was assessed using the Chi-square test for trend. Reproducibility was evaluated using kappa (k) scores, and radiologists' acceptance of the ILD-RADS was evaluated with a questionnaire.

RESULTS

We found a significant association between the ILD-RADS categories and patients' clinical diagnoses (P ≤ 0.0001) for the three readers, with a trend toward increased assignment of ILD-RADS-1 to IPF patients (50 %-57.1 %), and ILD-RADS-4 to non-IPF patients (46.4 %-49.5 %). The ILD-RADS categories showed excellent intra-reader agreement (k = 0.873) and moderate inter-reader agreement (k = 0.440). ILD-RADS-1 and -4 categories showed the highest inter-reader agreement (k = 0.681 and 0.481, respectively). Radiologists gave a positive response to using the ILD-RADS in daily practice.

CONCLUSIONS

The clinical utility of the ILD-RADS was demonstrated by the significant association between the ILD-RADS categories and patients' clinical diagnoses, particularly the ILD-RADS-1 and -4 categories. Excellent intra-reader and moderate inter-reader reproducibility was observed. ILD-RADS has the potential to be widely accepted for standardized HRCT reporting among radiologists.

Developing radiology diagnostic tools for pulmonary fibrosis using machine learning methods

BACKGROUND

Accurate and prompt diagnosis of the different patterns for pulmonary fibrosis is essential for patient management. However, accurate diagnosis of the specific pattern is challenging due to overlapping radiographic characteristics.

MATERIALS AND METHODS

We conducted a retrospective chart review utilizing two machine learning methods, classification and regression tree and Bayesian additive regression tree, to select the most important radiographic features for diagnosing the three most common fibrosis patterns and created an online diagnostic app for convenient implementation.

RESULTS

Four hundred patients (median age of 67 with inter quartile range 58-73; 200 males) were included in the study. Peripheral distribution, homogeneity, lower lobe predominance and mosaic attenuation of fibrosis are the four most important features identified. Bayesian additive regression tree demonstrates better performance than classification and regression tree in diagnosis prediction and provides the predicted probability of each diagnosis with uncertainty intervals for each combination of features.

CONCLUSION

The model and app built with Bayesian additive regression tree can be used as an effective tool in assisting radiologists in the diagnostic process of pulmonary fibrosis pattern recognition.

The compound artemisinin-hydroxychloroquine ameliorates bleomycin-induced pulmonary fibrosis in rats by inhibiting TGF-β1/Smad2/3 signaling pathway

Pulmonary fibrosis (PF) is a lethal disease characterized by a progressive decline in lung function. Currently, lung transplantation remains the only available treatment for PF. However, both artemisinin (ART) and hydroxychloroquine (HCQ) possess potential antifibrotic properties. This study aimed to investigate the effects and mechanisms of a compound known as Artemisinin-Hydroxychloroquine (AH) in treating PF, specifically by targeting the TGF-β1/Smad2/3 pathway. To do this, we utilized an animal model of PF induced by a single tracheal drip of bleomycin (BLM) in Sprague-Dawley (SD) rats. The PF animal models were administered various doses of AH, and the efficacy and safety of AH were evaluated through pulmonary function testing, blood routine tests, serum biochemistry tests, organ index measurements, and pathological examinations. Additionally, Elisa, western blotting, and qPCR techniques were employed to explore the potential molecular mechanisms of AH in treating PF. Our findings reveal that AH effectively and safely alleviate PF by inhibiting BLM-induced specific inflammation, reducing extracellular matrix (ECM) deposition, and interfering with the TGF-β1/Smad2/3 signaling pathway. Notably, the windfall for this study is that the inhibition of ECM may initiate self-healing in the BLM-induced PF animal model. In conclusion, AH shows promise as a potential therapeutic drug for PF, as it inhibits disease progression through the TGF-β1/Smad2/3 signaling pathway.

The Role of Radiology in Multidisciplinary Discussion of Patients With Interstitial Lung Diseases

Radiologists fulfill a vital role in the multidisciplinary care provided to patients with interstitial lung diseases and other diffuse parenchymal lung disorders. The diagnosis of interstitial lung diseases hinges on the consensus of clinical, radiology, and pathology medical subspecialists, but additional expertise from rheumatology, immunology, or hematology can be invaluable. The thin-section computed tomography (CT) features of lung involvement informs the diagnostic approach. Radiologists should be familiar with radiologic methods (including inspiratory/expiratory and prone imaging) and be well versed in the recognition of the CT features of fibrosis, assessment of the overall pattern of lung involvement, and classification according to the latest guidelines. We present a case-based review that highlights examples wherein CT features and subspecialist radiologist interpretation informed the multidisciplinary team consensus diagnosis and care pathways.

Guidelines of the Polish Respiratory Society on the Diagnosis and Treatment of Progressive Fibrosing Interstitial Lung Diseases Other than Idiopathic Pulmonary Fibrosis

The recommendations were developed as answers to previously formulated questions concerning everyday diagnostic and therapeutic challenges. They were developed based on a review of the current literature using the GRADE methodology. The experts suggest that PF-ILD be diagnosed based on a combination of different criteria, such as the aggravation of symptoms, progression of radiological lesions, and worsening of lung function test parameters. The experts recommend a precise diagnosis of an underlying disease, with serological testing for an autoimmune disease always being included. The final diagnosis should be worked out by a multidisciplinary team (MDT). Patients with an interstitial lung disease other than IPF who do not meet the criteria for the progressive fibrosis phenotype should be monitored for progression, and those with systemic autoimmune diseases should be regularly monitored for signs of interstitial lung disease. In managing patients with interstitial lung disease associated with autoimmune diseases, an opinion of an MDT should be considered. Nintedanib rather than pirfenidon should be introduced in the event of the ineffectiveness of the therapy recommended for the treatment of the underlying disease, but in some instances, it is possible to start antifibrotic treatment without earlier immunomodulatory therapy. It is also admissible to use immunomodulatory and antifibrotic drugs simultaneously. No recommendations were made for or against termination of anti-fibrotic therapy in the case of noted progression during treatment of a PF-ILD other than IPF. The experts recommend that the same principles of non-pharmacological and palliative treatment and eligibility for lung transplantation should be applied to patients with an interstitial lung disease other than IPF with progressive fibrosis as in patients with IPF.

Interobserver agreement regarding the Fleischner Society diagnostic criteria for usual interstitial pneumonia patterns on computed tomography

Objective

To assess interobserver agreement among radiologists regarding the current Fleischner Society diagnostic criteria for usual interstitial pneumonia (UIP) patterns on computed tomography (CT).

Materials and Methods

Using the Fleischner Society criteria for UIP CT patterns, five raters, working independently, categorized the high-resolution CT (HRCT) scans of 44 patients with interstitial lung disease who underwent lung biopsy. The raters also evaluated the presence, extent, and distribution of the most relevant imaging findings, as well as indicating their level of confidence in the most likely diagnosis and in up to three diagnostic hypotheses.

Results

There was moderate to substantial interobserver agreement regarding the UIP patterns on HRCT—kappa statistic (κ) = 0.59-0.61. Interobserver agreement for the binary scores was substantial (κ = 0.77-0.79), whereas that for the presence of honeycombing was almost perfect (κ = 0.81-0.96). There was agreement regarding at least one of the three diagnostic hypotheses in only 36.4% of the cases. For the level of confidence in the most likely diagnosis, there was only slight to fair agreement (κ = 0.19-0.21).

Conclusion

Interobserver agreement regarding the current Fleischner Society CT criteria for UIP was moderate to substantial among raters with varying levels of experience. There was only slight to fair agreement regarding the diagnostic hypotheses and for the level of confidence in the most likely diagnosis.

ACR Appropriateness Criteria® Diffuse Lung Disease

Diffuse lung disease, frequently referred to as interstitial lung disease, encompasses numerous disorders affecting the lung parenchyma. The potential etiologies of diffuse lung disease are broad with several hundred established clinical syndromes and pathologies currently identified. Imaging plays a critical role in diagnosis and follow-up of many of these diseases, although multidisciplinary discussion is the current standard for diagnosis of several DLDs. This document aims to establish guidelines for evaluation of diffuse lung diseases for 1) initial imaging of suspected diffuse lung disease, 2) initial imaging of suspected acute exacerbation or acute deterioration in cases of confirmed diffuse lung disease, and 3) clinically indicated routine follow-up of confirmed diffuse lung disease without acute deterioration. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Radiological pitfalls associated with the diagnosis of usual interstitial pneumonia pattern on high-resolution computed tomography and associated findings: experience from a single Italian center

BACKGROUND

The diagnostic algorithm for idiopathic pulmonary fibrosis (IPF) based on high-resolution computed tomography (HRCT) findings and multidisciplinary discussion (MDD) has been well established.

PURPOSE

To identify the causes of disagreement between non-thoracic and thoracic radiologist involved in MDD for the imaging diagnosis of usual interstitial pneumonia (UIP) patterns and associated findings on HRCT and to improve the understanding of IPF by non-expert radiologists through a more systematic approach to HRCT.

MATERIAL AND METHODS

This study included 68 patients who underwent MDD for suspected IPF. We compared the first reports generated before MDD by non-expert radiologists with the CT pattern and associated findings of IPF reported by thoracic radiologist involved in MDD.

RESULTS

Regarding the diagnosis of CT pattern by non-expert radiologists, 30/68 patients received a discordant diagnosis, and in another 28 reports, all features of the CT pattern were described without reaching a diagnostic conclusion. The first report was concordant in only 10 patients. For 63 cases in which associated findings were reported by expert radiologists in MDD, we documented discrepancies in 47 cases where associated findings were considered absent by the first non-thoracic radiologist.

CONCLUSION

We found significant discrepancies in the imaging diagnosis of UIP patterns and associated findings on HRCT between non-expert and thoracic radiologists included in MDD. Therefore, in this study, we analyzed and suggested diagnostic strategies to improve non-expert radiologists' approach to HRCT.

Radiomics-based assessment of idiopathic pulmonary fibrosis is associated with genetic mutations and patient survival

Purpose: The purpose of our study was to combine differences in radiomic features extracted from lung regions in the computed tomography (CT) scans of patients diagnosed with idiopathic pulmonary fibrosis (IPF) to identify associations with genetic variations and patient survival. Approach: A database of CT scans and genomic data from 169 patients diagnosed with IPF was collected retrospectively. Six region-of-interest pairs (three per lung, positioned posteriorly, anteriorly, and laterally) were placed in each of three axial CT sections for each patient. Thirty-one features were used in logistic regression to classify patients' genetic mutation status; classification performance was evaluated through the area under the receiver operating characteristic (ROC) curve [average area under the ROC curve (AUC)]. Kaplan-Meier (KM) survival curve models quantified the ability of each feature to differentiate between survival curves based on feature-specific thresholds. Results: Nine first-order texture features and one fractal feature were correlated with TOLLIP-1 (rs4963062) mutations (AUC: 0.54 to 0.74), and five Laws' filter features were correlated with TOLLIP-2 (rs5743905) mutations (AUC: 0.53 to 0.70). None of the features analyzed were found to be correlated with MUC5B mutations. First-order and fractal features demonstrated the greatest discrimination between KM curves. Conclusions: A radiomics approach for the correlation of patient genetic mutations with image texture features has potential as a biomarker. These features also may serve as prognostic indicators using a survival curve modeling approach in which the combination of radiomic features and genetic mutations provides an enhanced understanding of the interaction between imaging phenotype and patient genotype on the progression and treatment of IPF.

Practical Imaging Interpretation in Patients Suspected of Having Idiopathic Pulmonary Fibrosis: Official Recommendations from the Radiology Working Group of the Pulmonary Fibrosis Foundation

Imaging serves a key role in the diagnosis of patients suspected of having idiopathic pulmonary fibrosis (IPF). Accurate pattern classification at thin-section chest CT is a key step in multidisciplinary discussions, guiding the need for surgical lung biopsy and determining available pharmacologic therapies. The recent approval of new treatments for fibrosing lung disease has made it more critical than ever for radiologists to facilitate accurate and early diagnosis of IPF. This document was developed by the Radiology Working Group of the Pulmonary Fibrosis Foundation with the goal of providing a practical guide for radiologists. In this review, the critical imaging patterns of IPF, pitfalls in imaging classifications, confounding imaging findings with other fibrotic lung diseases, and reporting standards for cases of lung fibrosis will be discussed.

Published under a CC BY 4.0 license.

See also the commentary by White and Galvin in this issue.

Idiopathic pulmonary fibrosis: Current knowledge, future perspectives and its importance in radiation oncology

Idiopathic pulmonary fibrosis (IPF) is a progressive, fibrotic lung disease with an unknown cause. Uncertainties still remain regarding the pathogenesis of IPF, and the prognosis of this disease is poor despite some recent improvements in treatment. Radiation induced lung injury (RILI) is a common complication and a dose-limiting toxicity of thoracic radiotherapy. Importantly, IPF is a crucial risk factor for pulmonary toxicity after thoracic radiotherapy. Although IPF is not universally accepted as a definite contraindication for thoracic radiotherapy at present, it has been shown that IPF can increase the risk of severe and fatal complications after thoracic radiotherapy. Proton beam therapy has shown promising results in reducing the incidence of thoracic radiotherapy related life-threatening complications in IPF patients, but the current evidence is not sufficient to recommend the standard use of it. Many similarities are noticeable between IPF and RILI in terms of pathogenesis and underlying mechanisms. Better understanding of the mechanisms of IPF and RILI may enable clinicians to provide safer and more effective thoracic radiotherapy treatments in cancer patients with IPF. In this review, we summarize the current knowledge of IPF, present the importance of IPF in radiation oncology practice, and highlight the similarities and relationship between IPF and RILI.

HRCT evaluation of patients with interstitial lung disease: comparison of the 2018 and 2011 diagnostic guidelines

Background and aims:

Chest high-resolution computed tomography (HRCT) is the central diagnostic tool in discerning idiopathic pulmonary fibrosis (IPF) from other interstitial lung disease (ILDs). In 2018, new guidelines were published and the nomenclature for HRCT interpretation was changed. We sought to evaluate how clinicians’ interpretation would change based on reading HRCTs under the framework of the old versus new categorization.

Materials and methods:

We collated HRCTs from 50 random cases evaluated in the Inova Fairfax ILD clinic. Six ILD experts were provided the deidentified HRCTs. They were all instructed to independently provide two reads of each HRCT, based on the old and the new guidelines.

Results:

The kappa statistic for concordance for HRCT reads under old guidelines was 0.5, while for the new guidelines it was 0.38. Under the framework of the old guidelines, there were 22 HRCTs with unanimous consensus reads, while only 15 with the new guidelines. There were 12 HRCTs read unanimously as usual interstitial pneumonia (UIP) pattern based on both the old and the new guidelines. Ten HRCTs were read as a possible UIP pattern based on the old guidelines and were classified in nine cases as probable UIP and one indeterminate based on the new guidelines. Of the 28 inconsistent UIP HRCTs (old guidelines), 25 were read as alternative diagnosis suggested, two were read as indeterminate and one as probable UIP.

Conclusion:

Implementation of the new guidelines to categorize HRCTs in ILD patients appears to be associated with greater inter-interpreter variability. How or whether new guidelines improve the care and management of ILD patients remains unclear.

The reviews of this paper are available via the supplemental material section.

Cardiovascular implications of idiopathic pulmonary fibrosis: A way forward together?

Cardiovascular disease has an increased prevalence among patients with idiopathic pulmonary fibrosis (IPF). Cardiovascular disease and IPF share similar symptoms with overlapping demographics and risk factors for disease development. Common cellular mediators leading to disease development and progression have been identified in both the cardiovascular and pulmonary organ systems. In this context, discovery of new therapeutic targets and medical therapies could be mutually beneficial across cardiopulmonary diseases. Here we present (1) a clinical review of IPF for the cardiovascular clinician and (2) common cellular mechanisms responsible for fibrosis in the heart and lungs and (3) highlight future research considerations and the potential role of novel therapeutic agents which may be mutually beneficial in cardiac and pulmonary fibrosis.

Treatment of the Connective Tissue Disease-Related Interstitial Lung Diseases: A Narrative Review

Interstitial lung disease (ILD) is a frequent complication of patients with connective tissue disease (CTD) and significantly affects morbidity and mortality. Disease course may vary from stable or mildly progressive to more severe, with rapid loss of lung function. We conducted a search of PubMed (National Library of Medicine) and the Web of Science Core Collection using the key words lung, pulmonary, pneumonia, pneumonitis, and alveolar and subtypes of CTD. All clinical studies from January 1, 1980, through September 1, 2018, were reviewed for descriptions of specific therapies and their efficacy or safety and were categorized as controlled interventional trials, observational prospective or retrospective cohort studies, case series (>5 patients), and case reports (<5 patients). Low-quality reports (<5 patients) before 2000, reviews, editorials, popular science papers, and letters to the editor without complete descriptions of the therapies used or their outcomes were excluded. Directed therapy for CTD-ILD is dominated by empirical use of immunosuppressive agents, with the decision to treat, treatment choice, and treatment duration limited to cases and cohort observations. Only a few higher-level controlled studies were available specifically in scleroderma-related ILD. We summarize herein for the clinician the published treatment scope and experience, highlighted clinical response, and common adverse reactions for the management of CTD-ILD.

Pirfenidone attenuates lung fibrotic fibroblast responses to transforming growth factor-β1

BACKGROUND

Pirfenidone, an antifibrotic agent used for the treatment of idiopathic pulmonary fibrosis (IPF), functions by inhibiting myofibroblast differentiation, which is involved in transforming growth factor (TGF)-β1-induced IPF pathogenesis. However, unlike normal lung fibroblasts, the relationship between pirfenidone responses of TGF-β1-induced human fibrotic lung fibroblasts and lung fibrosis has not been elucidated.

METHODS

The effects of pirfenidone were evaluated in lung fibroblasts isolated from fibrotic human lung tissues after TGF-β1 exposure. The ability of two new pharmacological targets of pirfenidone, collagen triple helix repeat containing protein 1(CTHRC1) and four-and-a-half LIM domain protein 2 (FHL2), to mediate contraction of collagen gels and migration toward fibronectin were assessed in vitro.

RESULTS

Compared to control lung fibroblasts, pirfenidone significantly restored TGF-β1-stimulated fibroblast-mediated collagen gel contraction, migration, and CTHRC1 release in lung fibrotic fibroblasts. Furthermore, pirfenidone attenuated TGF-β1- and CTHRC1-induced fibroblast activity, upregulation of bone morphogenic protein-4(BMP-4)/Gremlin1, and downregulation of α-smooth muscle actin, fibronectin, and FHL2, similar to that observed post-CTHRC1 inhibition. In contrast, FHL2 inhibition suppressed migration and fibronectin expression, but did not downregulate CTHRC1.

CONCLUSIONS

Overall, pirfenidone suppressed fibrotic fibroblast-mediated fibrotic processes via inverse regulation of CTHRC1-induced lung fibroblast activity. Thus, CTHRC1 can be used for predicting pirfenidone response and developing new therapeutic targets for lung fibrosis.

Chest CT scan and alveolar procollagen III to predict lung fibroproliferation in acute respiratory distress syndrome

Background

Lung fibroproliferation in ARDS patients is associated with mortality. Alveolar procollagen III (NT-PCP-III) is a validated biomarker of lung fibroproliferation. A chest CT scan could be useful for the diagnosis of lung fibroproliferation. The aim of this study was to identify lung fibroproliferative CT scan aspects in ARDS patients with high levels of NT-PCP-III.

Results

This retrospective study included ARDS patients who had at least one assessment of alveolar NT-PCP-III and a chest CT scan within 3 days before or after NT-PCP-III determination. An alveolar level of NT-PCP-III > 9 µG/L indicated fibroproliferation. The CT scan was scored on interstitial and alveolar abnormalities. Each lobe was scored from 0 to 5 according to the severity of the abnormalities. The crude score and the corrected score (related to the number of scored lobes in cases of important lobar condensation or lobectomy) were used. One hundred ninety-two patients were included, for a total of 228 alveolar NT-PCP-III level and CT scan ‘couples’. Crude and corrected CT scan fibrosis scores were higher in the fibroproliferation group compared with the no fibroproliferation group (crude score: 12 [9–17] vs 14 [11–12], p = 0.002; corrected score: 2.8 [2.2–4.0] vs 3.4 [2.5–4.7], p < 0.001). CT scan fibrosis scores and NT-PCP-III levels were significantly but weakly correlated (crude score: ρ = 0.178, p = 0.007; corrected score: ρ = 0.184, p = 0.005).

Conclusions

When the alveolar level of NT-PCP-III was used as a surrogate marker of histological lung fibroproliferation, the CT scan fibrosis score was significantly higher in patients with active lung fibroproliferation. Pulmonary condensation is the main limitation to diagnosing fibroproliferation during ARDS.

Electronic supplementary material

The online version of this article (10.1186/s13613-019-0516-9) contains supplementary material, which is available to authorized users.

Interpretation of HRCT Scans in the Diagnosis of IPF: Improving Communication Between Pulmonologists and Radiologists

Idiopathic pulmonary fibrosis (IPF) is a progressive fibrosing interstitial lung disease (ILD). In this review, we describe the central role of high-resolution computed tomography (HRCT) in the diagnosis of IPF and discuss how communication between pulmonologists and radiologists might be improved to make the interpretation of HRCT scans more effective. Clinical information is important in the interpretation of HRCT scans, as the likelihood that specific radiologic features reflect IPF is not absolute, but dependent on the clinical context. In cases where the clinical context or HRCT pattern are inconclusive, multidisciplinary discussion (MDD) between a pulmonologist and radiologist (and, where relevant, a pathologist and rheumatologist) experienced in the differential diagnosis of ILD is necessary to establish a diagnosis. While it can be challenging to convene a face-to-face meeting, MDD can be conducted virtually or by telephone to enable each specialty group to contribute. To make the MDD most effective, it is important that relevant clinical information (for example, on the patient’s clinical history, exposures and the results of serological tests) is shared with all parties in advance. A common lexicon to describe HRCT features observed in ILD can also help improve the effectiveness of MDD. A working diagnosis may be made in patients who do not fulfill all the diagnostic criteria for any specific type of ILD, but this diagnosis should be reviewed at regular intervals, with repeat of clinical, radiological, and laboratory assessments as appropriate, as new information pertinent to the patient’s diagnosis may become available.

Effect of Recombinant Human Pentraxin 2 vs Placebo on Change in Forced Vital Capacity in Patients With Idiopathic Pulmonary Fibrosis: A Randomized Clinical Trial

IMPORTANCE

Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic lung disease with poor prognosis. Approved therapies do not halt disease progression.

OBJECTIVE

To determine the effect of recombinant human pentraxin 2 vs placebo on change from baseline to week 28 in mean forced vital capacity (FVC) percentage of predicted value.

DESIGN, SETTING, AND PARTICIPANTS

Phase 2, randomized, double-blind, placebo-controlled trial conducted at 18 sites in 7 countries of eligible patients with IPF (N = 117; aged 40-80 years; FVC ≥50% and ≤90% predicted; ratio of forced expiratory volume in the first second/FVC >0.70; diffusing capacity for carbon monoxide [Dlco] ≥25% and ≤90% predicted; and distance of ≥150 m on the 6-minute walk test). Study period was August 2015-May 2017.

INTERVENTIONS

Patients were randomized to receive either recombinant human pentraxin 2 (10 mg/kg intravenous every 4 weeks, n = 77) or placebo (n = 39) for 24 weeks, and stratified by concurrent IPF treatment status.

MAIN OUTCOMES AND MEASURES

The primary end point was the least-squares mean change in FVC percentage of predicted value from baseline to week 28 (minimal clinically important difference, decline of 2%-6%). Secondary end points included mean change in lung volumes (total, normal, and interstitial lung abnormalities) on high-resolution computed tomography (HRCT) and 6-minute walk distance (minimal clinically important difference, 24-45 m).

RESULTS

Of 117 randomized patients, 116 received at least 1 dose of study drug (mean age, 68.6 years; 81.0% men; mean time since IPF diagnosis, 3.8 years), and 111 (95.7%) completed the study. The least-squares mean change in FVC percentage of predicted value from baseline to week 28 in patients treated with recombinant human pentraxin 2 was -2.5 vs -4.8 for those in the placebo group (difference, +2.3 [90% CI, 1.1 to 3.5]; P = .001). No significant treatment differences were observed in total lung volume (difference, 93.5 mL [90% CI, -27.7 to 214.7]), quantitative parenchymal features on HRCT (normal lung volume difference, -1.2% [90% CI, -4.4 to 1.9]; interstitial lung abnormalities difference, 1.1% [90% CI, -2.2 to 4.3]), or measurement of Dlco (difference, -0.4 [90% CI, -2.6 to 1.7]). The change in 6-minute walk distance was -0.5 m for patients treated with recombinant human pentraxin 2 vs -31.8 m for those in the placebo group (difference, +31.3 m [90% CI, 17.4 to 45.1]; P < .001). The most common adverse events in the recombinant human pentraxin 2 vs placebo group were cough (18% vs 5%), fatigue (17% vs 10%), and nasopharyngitis (16% vs 23%).

CONCLUSIONS AND RELEVANCE

In this preliminary study, recombinant human pentraxin 2 vs placebo resulted in a slower decline in lung function over 28 weeks for patients with idiopathic pulmonary fibrosis. Further research should more fully assess efficacy and safety.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT02550873.

Series of rare lung diseases mimicking imaging patterns of common diffuse parenchymal lung diseases

Diffuse parenchymal lung diseases (DPLDs) encompass a variety of restrictive and obstructive lung pathologies. In this article, the authors discuss a series of rare pulmonary entities and their high-resolution computed tomography imaging appearances, which can mimic more commonly encountered patterns of DPLDs. These cases highlight the importance of surgical lung biopsies in patients with imaging findings that do not show typical imaging features of usual interstitial pneumonia.

Radiographic Differentiation of Advanced Fibrocystic Lung Diseases

The concept of end-stage lung disease suggests a final common pathway for most diffuse parenchymal lung diseases. In accordance with this concept, end-stage disease is characterized radiographically and pathologically by the presence of extensive honeycombing. However, sequential computed tomographic (CT) scans obtained from patients with chronic diffuse lung disease evolve over time to show various advanced lung disease patterns other than honeycombing. In addition, several radiographically distinct honeycomb patterns, including microcystic, macrocystic, mixed, and combined emphysema and honeycombing, differentiate one advanced lung disease from another. For example, usual interstitial pneumonia (IP) usually shows mixed microcystic and macrocystic honeycombing. In contrast, CT images of long-standing fibrotic nonspecific IP typically show only small, scattered foci of honeycombing; instead, most enlarged airspaces observed in the advanced stage of this disease represent dilatation of bronchioles. In desquamative IP and pulmonary Langerhans cell histiocytosis, focal opacities typically evolve into emphysema-like lesions seen on CT imaging. In combined pulmonary fibrosis and emphysema and sarcoidosis, the cysts tend to be larger than those observed in usual IP. Sequential CT scans in other chronic, diffuse lung diseases also show various distinctive changes. This article highlights radiographic patterns of lung destruction that belie a single common pathway to end-stage lung disease. Recognition of distinct radiographic patterns of lung destruction can help differentiate diffuse parenchymal lung diseases, even in advanced stages of disease evolution.

Imaging of Idiopathic Pulmonary Fibrosis

Idiopathic interstitial pneumonias are a heterogeneous group of diffuse lung diseases characterized by distinct clinicopathologic entities with the usual interstitial pneumonia (UIP) being the most common. The pattern of UIP can be seen in idiopathic pulmonary fibrosis (IPF) as well as in secondary causes, most commonly in connective tissue diseases. IPF is usually progressive and associated with a very poor prognosis, and newer therapies pose a risk of serious complications; therefore, diagnostic certainty is crucial. This article reviews the radiologic findings in UIP with clinical correlation and histopathologic features along with its significance for prognosis and patients monitoring.

Ockham's razor for the MET-driven invasive growth linking idiopathic pulmonary fibrosis and cancer

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) identifies a specific lung disorder characterized by chronic, progressive fibrosing interstitial pneumonia of unknown etiology, which lacks effective treatment. According to the current pathogenic perspective, the aberrant proliferative events in IPF resemble those occurring during malignant transformation.

MAIN BODY

Receptor tyrosine kinases (RTK) are known to be key players in cancer onset and progression. It has been demonstrated that RTK expression is sometimes also altered and even druggable in IPF. One example of an RTK-the MET proto-oncogene-is a key regulator of invasive growth. This physiological genetic program supports embryonic development and post-natal organ regeneration, as well as cooperating in the evolution of cancer metastasis when aberrantly activated. Growing evidence sustains that MET activation may collaborate in maintaining tissue plasticity and the regenerative potential that characterizes IPF.

CONCLUSION

The present work aims to elucidate-by applying the logic of simplicity-the bio-molecular mechanisms involved in MET activation in IPF. This clarification is crucial to accurately design MET blockade strategies within a fully personalized approach to IPF.