A new proposal for phenotypic classification and outcome assessment of dermatomyositis based on clinical manifestations and serological testing.

BACKGROUND: Dermatomyositis (DM) is an infrequent disease subgroup of idiopathic inflammatory myopathies characterized by distinct skin lesions. However, high heterogeneity makes clinical diagnosis and treatment of DM very challenging. OBJECTIVES: Unsupervised classification in DM patients and analysis of key factors related to clinical outcomes. METHODS: This retrospective study was conducted between 2017 and 2022 at the Department of Rheumatology, Xiangya Hospital, Central South University. 162 DM patients were enrolled for unsupervised hierarchical cluster analysis. In addition, we divided the clinical outcomes of DM patients into four subgroups: withdrawal, stabilization, aggravation, and death, and compared the clinical profiles amongst the subgroups. RESULTS: Out of 162 DM patients, three clusters were defined. Cluster 1 (n = 40) was mainly grouped by patients with prominent muscular involvement and mild Interstitial Lung Disease (ILD). Cluster 2 (n = 72) grouped patients with skin rash, anti-Melanoma Differentiation Associated protein 5 positive (anti-MDA5+), and Rapid Progressive Interstitial Lung Disease (RP-ILD). Cluster 3 (n = 50) grouped patients with the mildest symptoms. The proportion of death increased across the three clusters (cluster 3 < cluster 1 < cluster 2). STUDY LIMITATIONS: The number of cases was limited for the subsequent construction and validation of predictive models. We did not review all skin symptoms or pathological changes in detail. CONCLUSIONS: We reclassified DM into three clusters with different risks for poor outcome based on diverse clinical profiles. Clinical serological testing and cluster analysis are necessary to help clinicians evaluate patients during follow-up and conduct phenotype-based personalized care in DM.

Two-Stage Hybrid Approach of Deep Learning Networks for Interstitial Lung Disease Classification.

High-resolution computed tomography (HRCT) images in interstitial lung disease (ILD) screening can help improve healthcare quality. However, most of the earlier ILD classification work involves time-consuming manual identification of the region of interest (ROI) from the lung HRCT image before applying the deep learning classification algorithm. This paper has developed a two-stage hybrid approach of deep learning networks for ILD classification. A conditional generative adversarial network (c-GAN) has segmented the lung part from the HRCT images at the first stage. The c-GAN with multiscale feature extraction module has been used for accurate lung segmentation from the HRCT images with lung abnormalities. At the second stage, a pretrained ResNet50 has been used to extract the features from the segmented lung image for classification into six ILD classes using the support vector machine classifier. The proposed two-stage algorithm takes a whole HRCT as input eliminating the need for extracting the ROI and classifies the given HRCT image into an ILD class. The performance of the proposed two-stage deep learning network-based ILD classifier has improved considerably due to the stage-wise improvement of deep learning algorithm performance.

A new standard scoring for interstitial pneumonia based on quantitative analysis of ultrasonographic data: A study on COVID-19 patients.

OBJECTIVE: To assess the effectiveness of 3 novel lung ultrasound (LUS)-based parameters: Pneumonia Score and Lung Staging for pneumonia staging and COVID Index, indicating the probability of SARS-CoV-2 infection. METHODS: Adult patients admitted to the emergency department with symptoms potentially related to pneumonia, healthy volunteers and clinical cases from online accessible databases were evaluated. The patients underwent a clinical-epidemiological questionnaire and a LUS acquisition, following a 14-zone protocol. For each zone, a Pneumonia score from 0 to 4 was assigned by the algorithm and by an expert operator (kept blind with respect to the algorithm results) on the basis of the identified imaging signs and the patient Lung Staging was derived as the highest observed score. The output of the operator was considered as the ground truth. The algorithm calculated also the COVID Index by combining the automatically identified LUS markers with the questionnaire answers and compared with the nasopharyngeal swab results. RESULTS: Overall, 556 patients were analysed. A high agreement between the algorithm assignments and the expert operator evaluations was observed, both for Pneumonia Score and Lung Staging, with the latter having sensitivity and specificity over 92% both in the discrimination between healthy/sick patients and between sick patients with mild/severe pneumonia. Regarding the COVID Index, an area under the curve of 0.826 was observed for the classification of patients with/without SARS-CoV-2. CONCLUSION: The proposed methodology allowed the identification and staging of patients suffering from pneumonia with high accuracy. Moreover, it provided the probability of being infected by SARS-CoV-2.

Characteristics and mortality in primary Sjögren syndrome-related interstitial lung disease.

ABSTRACT: Aim of the study was to determine the characteristics and prognosis, and to identify the risk factors for mortality in patients with primary Sjögren syndrome (pSS) with interstitial lung disease (pSS-ILD).A total of 1422 patients with SS were screened and 178 patients with pSS-ILD were recruited. The medical records and outcomes were retrospectively reviewed. Overall survival and case control study were performed to explore the predictors of death.Among 178 pSS-ILD patients, 87.1% were women. Mean age was 61.59 ±â€Š11.69-year-old. Median disease duration was 72.0 (24.0, 156.0) months. Nonspecific interstitial pneumonia was the predominant high-resolution computed tomography pattern (44.9%). Impairment in diffusion capacity was the most common abnormality of pulmonary function test (75.8%) and the most severe consequence. Type 1 respiratory failure and hypoxia were observed in 15.0% and 30.0% patients, respectively. Mean survival time after confirmation of pSS-ILD diagnosis was 9.0 (6.8, 13.0) years. The 10-year survival rate for all patients with pSS-ILD was 81.7%. Forty-four (24.7%) of 178 patients died during the follow-up period. The most predominant cause of death was respiratory failure (n = 27). Twenty-seven patients died of ILD and formed study group. The 78 patients who survived formed control group. Age and smoking were risk factors for mortality in patients with pSS-ILD. In addition, severity of ILD, as reflected by high-resolution computed tomography, pulmonary function test, and arterial blood gas, was an independent risk factor. However, inflammation status (erythrocyte sedimentation rate, C-reactive protein) and anti-Sjögren syndrome-related antigen A and anti-Sjögren syndrome-related antigen B were not.ILD is a severe complication of pSS. Age, smoking, and severity of lung involvement are more critical for prognosis rather than inflammation status and autoantibodies.

Diagnostic and prognostic implications of 2018 guideline for the diagnosis of idiopathic pulmonary fibrosis in clinical practice.

The purpose of this study was to evaluate the implications of the 2018 updated guideline for the diagnosis of idiopathic pulmonary fibrosis (IPF) in clinical practice compared to 2011 guideline. This study involved 535 patients including 339 IPF and 196 non-IPF, and we retrospectively evaluated CT classifications of usual interstitial pneumonia (UIP) by two guidelines. Interobserver agreement of 2018 criteria showed moderate reliability (κ = 0.53) comparable to 2011 (κ = 0.56) but interobserver agreement for probable UIP was fair (κ = 0.40). CT pattern of indeterminate for UIP was associated with better prognosis compared with the other groups (adjusted hazard ratio [HR] = 0.36, p < 0.001). Compared to possible UIP, probable UIP demonstrated a lower positive predictive value (PPV, 62.9% vs 65.8%). In analysis of patients with CT patterns of non-definite UIP, diagnosing IPF when CT pattern showed probable UIP with lymphocyte count ≤ 15% in BAL fluid, and either male sex or age ≥ 60 years showed a high specificity of 90.6% and a PPV of 80.8% in the validation cohort. The 2018 criteria provide better prognostic stratification than the 2011 in patients with possible UIP. BAL fluid analysis can improve the diagnostic certainty for IPF diagnosis in patients with probable UIP CT pattern.

Diagnostic Classification of Interstitial Lung Disease in Clinical Practice.

Interstitial lung diseases (ILDs) are challenging to diagnose, requiring integration of multiple complex features that are often difficult to interpret. This article reviews a pragmatic approach to ILD diagnosis and classification, focusing on diagnostic tools and strategies that are used to separate different subtypes and identify the most appropriate management. We discuss the evolution of ILD classification and the contemporary approach that integrates routinely used diagnostic tools in a multidisciplinary discussion. We highlight the increasing importance of taking a multipronged approach to ILD classification that reflects the recent emphasis on disease behavior while also considering etiopathogenesis and morphologic features.

Low dose computed tomography of the lung for detection and grading of interstitial lung disease: A systematic simulation study.

PURPOSE: HRCT is the preferred imaging technique to evaluate Interstitial-Lung-Disease. Optimal Low-Dose-Computed-Tomography protocol for monitoring ILD with lowest radiation dose and optimal diagnostic accuracy and image quality unknown. METHODS: 28 Patients underwent HRCT. Image reconstructions with varying combinations of tube current (50mA, 20mA, 15 mA, 10mA) and image-thickness/increment (1/1mm, 2/2mm, 3/2.4mm, 5/4mm) were simulated from raw data. 448 CTs evaluated by 2 readers on image quality and ILD-specific features (ground glass opacification (ggo), honeycombing (hc), reticulation (ret)). RESULTS: Reduced dose settings with 20 mA did not show any significant difference to standard dose settings for all parameters in reader 1, while results were significantly altered in reader 2. Slice thickness did not significantly influence rating of typical ILD features like ggo, hc, ret or total disease extent. The correct differentiation between UIP and NSIP could be made on all dose settings and with all slice thickness. It was even found, that an increased slice thickness can compensate for the noise associated image quality degradation. Overall, for ggo detection a combination of 20 mA and 3 or 5 mm slice thickness was not different to the original evaluation. CONCLUSIONS: Assessment of ILD specific CT features down to 20 mA and a slice thickness of 3 or 5 mm is feasible.

Evaluation of health-related quality of life and the related factors in a group of Chinese patients with interstitial lung diseases.

INTRODUCTION: Interstitial lung diseases (ILDs) include a wide variety of chronic progressive pulmonary diseases characterized by lung inflammation, fibrosis and hypoxemia and can progress to respiratory failure and even death. ILDs are associated with varying degrees of quality of life impairments in affected people. Studies on the quality of life in patients with ILDs are still limited, and there are few studies with long-term follow-up periods in these patients. METHODS: Data from patients who were clinically diagnosed with ILDs in the Respiratory Department, Beijing Chaoyang Hospital, Capital Medical University from January 2017 to February 2018 were collected. Clinical status and HRQoL were assessed at baseline and subsequently at 6- and 12-month intervals with the LCQ, mMRC, HADS, SF-36, and SGRQ. Multivariate linear regression was used to evaluate the determinants of the decline in HRQoL. RESULTS: A total of 139 patients with idiopathic interstitial pneumonia (IIP) and 30 with connective tissue disease-associated ILD (CTD-ILD) were enrolled, 140 of whom completed the follow-up. The mean age was 63.7 years, and 92 patients were men. At baseline, the decline in HRQoL assessed by the SF-36 and SGRQ was significantly associated with the mMRC, LCQ and HADS depression score. In the follow-up, changes in FVC%, DLco%, mMRC and LCQ were significantly associated with changes in HRQoL. CONCLUSIONS: HRQoL in both IIP and CTD-ILD patients deteriorates to varying degrees, and the trend suggests that poor HRQoL in these patients is associated with many determinants, primarily dyspnea, cough and depression. Improving HRQoL is the main aim when treating patients living with ILDs.

Interstitial lung diseases in children.

Interstitial lung disease (ILD) in children (chILD) is a heterogeneous group of rare respiratory disorders that are mostly chronic and associated with high morbidity and mortality. The pathogenesis of the various chILD is complex and the diseases share common features of inflammatory and fibrotic changes of the lung parenchyma that impair gas exchanges. The etiologies of chILD are numerous. In this review, we chose to classify them as ILD related to exposure/environment insults, ILD related to systemic and immunological diseases, ILD related to primary lung parenchyma dysfunctions and ILD specific to infancy. A growing part of the etiologic spectrum of chILD is being attributed to molecular defects. Currently, the main genetic mutations associated with chILD are identified in the surfactant genes SFTPA1, SFTPA2, SFTPB, SFTPC, ABCA3 and NKX2-1. Other genetic contributors include mutations in MARS, CSF2RA and CSF2RB in pulmonary alveolar proteinosis, and mutations in TMEM173 and COPA in specific auto-inflammatory forms of chILD. However, only few genotype-phenotype correlations could be identified so far. Herein, information is provided about the clinical presentation and the diagnosis approach of chILD. Despite improvements in patient management, the therapeutic strategies are still relying mostly on corticosteroids although specific therapies are emerging. Larger longitudinal cohorts of patients are being gathered through ongoing international collaborations to improve disease knowledge and targeted therapies. Thus, it is expected that children with ILD will be able to reach the adulthood transition in a better condition.

Hospitalisation patterns of patients with interstitial lung disease in the light of comorbidities and medical treatment - a German claims data analysis.

BACKGROUND: Interstitial lung disease (ILD) is a heterogeneous group of mainly chronic lung diseases differing in disease course and prognosis. For most subtypes, evidence on relevance and outcomes of hospitalisations is lacking. METHODS: Using German claims data we investigated number of hospitalisations (zero-inflated-negative-binomial models providing rate ratios (RR)) and time to first hospitalisation (Cox proportional-hazard models providing hazard ratios (RR)) for nine ILD-subtypes. Models were stratified by ILD-related and non-ILD-related hospitalisations. We adjusted for age, gender, ILD-subtype, ILD-relevant comorbidities and ILD-medication (immunosuppressive drugs, steroids, anti-fibrotic drugs). RESULTS: Among 36,816 ILD-patients (mean age 64.7 years, 56.2% male, mean observation period 9.3 quarters), 71.2% had non-ILD-related and 56.6% ILD-related hospitalisations. We observed more and earlier non-ILD-related hospitalisations in ILD patients other than sarcoidosis. Medical ILD-treatment was associated with increased frequency and in case of late initiation, earlier (non-)ILD-related hospitalisations. Comorbidities were associated with generally increased hospitalisation frequency except for COPD (RR = 0.90) and PH (RR = 0.94) in non-ILD-related and for lung cancer in ILD-related hospitalisations (RR = 0.89). Coronary heart disease was linked with earlier (ILD-related: HR = 1.17, non-ILD-related HR = 1.19), but most other conditions with delayed hospitalisations. CONCLUSION: Hospitalisations are frequent across all ILD-subtypes. The hospitalisation risk might be reduced independently of the subtype by improved management of comorbidities and improved pharmacological and non-pharmacological ILD therapy.

Childhood diffuse parenchymal lung diseases: We need a new classification.

INTRODUCTION: Childhood diffuse parenchymal lung diseases (DPLD) are a heterogeneous group of respiratory disorders of both known and unknown causes that share common histological features. To date, there is not an exact consensus about the terminology, classification, therapy and follow up of this disease because of its rarity and wide clinical spectrum. OBJECTIVES: In this study, we tried to classify our DPLD patients according to the last classification scheme (chILD Network Classification). METHODS: The files of the children diagnosed with DPLD at our university hospital between 1974 and 2012 were retrospectively investigated. Clinical features, laboratory, radiological and histopathological findings, therapy and follow-up outcomes of these patients were recorded and evaluated according to the actual information and definitions. RESULTS: We described 130 DPLD patients, the largest childhood DPLD series from a single center, classified in 16 distinct groups according to their diagnosis. Our largest group in this serie is pulmonary hemosiderosis (28.5%); idiopathic interstitial pneumonias, pulmonary hemosiderosis, sarcoidosis and lipid storage diseases with lung involvement represent the 70% of the diagnoses. When we classified our patients according to the chILD Network Classification; patients with idiopathic interstitial pneumonia older than 2 years, idiopathic pulmonary hemosiderosis, pulmonary alveolar microlithiasis and diffuse chondroid malformation of the lung stayed out of this classification. CONCLUSION: To ensure a consensus about the therapy and follow up, we have to make revisions and reorganisations on the DPLD classification which was proposed in 2007. We need a new childhood DPLD classification that will cover all these disease groups.

[Childhood Interstitial Lung Disease in Infancy. Classification, diagnosis and management]. / Enfermedades del intersticio pulmonar en niños menores de 2 años. Clasificación, diagnóstico y tratamiento.

Childhood interstitial lung diseases, which some authors refer to as diffuse diseases of the lung, constitute a group of entities that are characterized by remodeling of the interstitium and distal airspaces that cause disturbances of gas exchange in the lungs. While some entities have few symptoms and naturally evolve favorably, others are potentially lethal. Its etiology is very varied, including forms of genetic cause, infectious origin, associated with systemic diseases, drugs and some remain of unknown origin. At present, the development of genetic testing allows diagnosing a group of pathologies, avoiding sometimes a lung biopsy. Its treatment includes different immunosuppressive and immunomodulatory drugs, mainly corticosteroids and hydroxychloroquine, which aim to reduce inflammation, stabilize the disease and prevent the phenomena of remodeling and fibrosis. This consensus is focused on children under 2 years of age, because most of the new entities recently described are manifested at this age.

Las enfermedades intersticiales pulmonares en la infancia, a las que algunos autores se refieren como enfermedades difusas del pulmón, constituyen un grupo de entidades que se caracteriza por la remodelación del intersticio y de los espacios aéreos distales. Mientras algunas entidades tienen pocos síntomas y evolucionan naturalmente en forma favorable, otras pueden ser letales. Su etiología es muy variada e incluye formas de causa genética, origen infeccioso, asociadas a enfermedades sistémicas, fármacos y algunas son de causa desconocida. El desarrollo de estudios genéticos permite, actualmente, diagnosticar un grupo de patologías y, en ocasiones, evitar la biopsia pulmonar. Su tratamiento incluye diferentes drogas inmunosupresoras e inmunomoduladores, sobre todo, corticoides e hidroxicloroquina, que tienen el objetivo de reducir la inflamación y prevenir los fenómenos de remodelación y la fibrosis. Este consenso está enfocado en los niños menores de 2 años, debido a que la mayoría de las nuevas entidades descritas recientemente se manifiestan a esta edad.

Enfermedades pulmonares intersticiales. Una perspectiva actual / Update on interstitial lung diseases

Interstitial lung diseases are a broad, diverse, challenging group of diseases, most of them chronic whose prognosis is not good. In the last two decades there have been considerable advances in the knowledge of the epidemiology, pathological and genetic bases and treatment of several of these diseases. This article summarizes and presents updated information about their classification, new knowledge on genetics and treatments in idiopathic pulmonary fibrosis, advances in the diagnosis and management of hypersensitivity pneumonitis and a review of the broad spectrum of interstitial diseases associated with connective tissue diseases. Several clinical trials are currently underway whose results will be available in the coming years and will provide more information and tools to improve the treatment of these patients.

Children's interstitial and diffuse lung disease.

Children's interstitial and diffuse lung disease (chILD) is a rare heterogenous group of conditions, with symptoms often overlapping with more common conditions, impeding diagnosis and frustrating parents and clinicians alike. Clinical collaborations are improving diagnostic precision, disease phenotyping, mechanistic understanding, and interventional therapeutic capability; however, with over 200 conditions, chILD requires greater aligned international collaboration to address the knowledge gaps. The use of genetics plays an increasing part in diagnosis, and thus might help to align current classification systems. Empirical therapeutics are few, of no proven benefit, and with important side-effects, particularly in infants. Novel therapeutics postulated for several chILD conditions on the basis of mechanistic observations are in development and represent real hope for those conditions to which they apply. Broader therapeutics against the downstream effects (ie, fibrosis) are under consideration for chILD conditions, but require adequately validated biological outcome measures, which the chILD community urgently needs to address.

Multidisciplinary approach in the diagnosis of idiopathic nonspecific interstitial pneumonia.

The article provides a modern classification of interstitial lung diseases. The focus is on the poorly studied and difficult to diagnose idiopathic nonspecific interstitial pneumonia, isolated in a separate nosological form and included in the classification only in 2002. The paper presents the features of the clinical, radiological, histological picture of idiopathic nonspecific interstitial pneumonia in comparison with idiopathic pulmonary fibrosis. The presented materials are based on the results of the largest study conducted by the working group of the American Thoracic Society, which shows the importance of the interaction of specialists in the diagnosis of idiopathic nonspecific interstitial pneumonia. A comprehensive assessment of the examination of patients conducted in collaboration with the clinician and radiologist, after their cooperative discussion, in many cases can help to avoid lung biopsy, and the study of morphological material is more often necessary only in difficult diagnostic situations.

Interstitial Pneumonia with Autoimmune Features and Undifferentiated Connective Tissue Disease.

In 2015, a multidisciplinary task force comprising pulmonologists, rheumatologists, pathologists, and radiologists representing the European Respiratory Society and American Thoracic Society published a diagnostic classification schema for individuals with interstitial lung disease and autoimmune features who did not meet criteria for a defined connective tissue disease. The term interstitial pneumonia with autoimmune features (IPAF) was applied. Classification criteria are often nonspecific, but up to 90% of subjects with IPAF have serological evidence for autoimmunity (particularly (+) antinuclear antibodies). Distinguishing patients with IPAF from idiopathic pulmonary disorders may be difficult. The natural history and appropriate management of IPAF have not been clarified, as data are largely limited to retrospective studies. In this review, we discuss the salient clinical, serologic, histologic, and radiographic features of IPAF and discuss an approach to management.

Incidence and risk factors of interstitial lung disease of patients with head and neck cancer treated with cetuximab.

BACKGROUND: Interstitial lung disease (ILD) is known as a potentially severe adverse event associated with epidermal growth factor receptor (EGFR)-targeted therapy. The incidence and risk factors of ILD in patients with head and neck squamous cancer (HNSCC) treated with cetuximab, an anti-EGFR monoclonal antibody, have not been established. METHODS: We retrospectively reviewed patients with HNSCC who received cetuximab from December 2012 to December 2016 at our institute and evaluated the incidence and risk factors of ILD. RESULTS: Of the 201 patients with HNSCC, ILD was observed in 9 patients (4.5%), 8 of whom had grade 3 or higher. High Krebs von den Lungen-6 (KL-6) and ≥50 pack-years of smoking were significantly predictive of associated with ILD (P = 0.00011 and 0.05, respectively). CONCLUSION: The incidence of ILD in patients with HNSCC treated with cetuximab was <5%, but most of the ILD cases were severe. High KL-6 and smoking histories might be predictive for ILD among patients with HNSCC.

In vivo probe-based confocal laser endomicroscopy in chronic interstitial lung diseases: Specific descriptors and correlation with chest CT.

BACKGROUND AND OBJECTIVE: Probe-based confocal laser endomicroscopy (pCLE) enables in vivo microimaging of the distal lung, during bronchoscopy. This study aims at identifying pCLE descriptors of chronic interstitial lung diseases (ILD), their correlations with chest HRCT and assessing inter-observer agreement. METHODS: pCLE was performed in 21 healthy volunteers (HV) and 59 non-smoking ILD patients, including 19 patients with idiopathic pulmonary fibrosis (IPF) or asbestosis, 15 with connective tissue disease-associated ILD (CTD-ILD), 17 with sarcoidosis and 8 with hypersensitivity pneumonitis (HP). pCLE descriptors were identified in ILD on the basis of comparison with HV. RESULTS: Nine pCLE descriptors were more frequent in ILD compared to HV, with good inter-observer agreement, including fluorescent bronchiolar cells (sarcoidosis, CTD-ILD and HP), fluorescent alveolar cells (CTD-ILD and HP), small alveolar entrance rings (IPF or asbestosis and CTD-ILD), enlarged axial elastic fibres (IPF or asbestosis), septal fibres (IPF or asbestosis, CTD-ILD and HP), disorganized acinar network and rigid acinar network (IPF or asbestosis and CTD-ILD), dense elastic network (IPF or asbestosis) and alveolar fluorescent nodular structures (in sarcoidosis) (P < 0.01, Fisher's exact test, all comparisons). The distribution of nodules on computed tomography (CT) appeared to correlate with pCLE alveolar nodular structures, rigid acinar network and septal fibres, while reticulations were associated with septal fibres and disorganized or dense acinar network; ground-glass opacities on CT with small alveolar entrances, rigid elastic network and septal fibres; and honeycombing with septal fibres. CONCLUSION: In the four groups of ILD studied, 9 pCLE descriptors are described, which appear specific and reproducible, and correlate with chest HRCT patterns.

Tissue Continues to Be the Issue: Role of Histopathology in the Context of Recent Updates in the Radiologic Classification of Interstitial Lung Diseases.

CONTEXT.­: High-resolution computed tomography (HRCT) imaging has an increasingly important role in clinical decision-making in patients with interstitial lung diseases. The recent Fleischner Society white paper on the diagnostic criteria for idiopathic pulmonary fibrosis highlights the advances in our understanding of HRCT imaging in interstitial lung diseases. OBJECTIVE.­: To discuss the evidence and recommendations outlined in the white paper as it pertains to the radiologic diagnosis of interstitial lung disease, specifically highlighting the current limitations of HRCT in confidently predicting histopathologic findings. DATA SOURCES.­: The recent Fleischner Society white paper and other studies pertaining to the role of HRCT in predicting histopathology in interstitial lung diseases are reviewed. CONCLUSIONS.­: High-resolution computed tomography is highly predictive of a usual interstitial pneumonia (UIP) pattern on histopathology when the HRCT shows a typical UIP pattern on a "confident" read by the radiologist. A probable UIP pattern is also very predictive of a UIP pattern on histopathology, and histopathologic confirmation is not needed for most patients demonstrating this pattern in the appropriate clinical setting. A UIP pattern may be seen in a substantial proportion of patients with an "indeterminate UIP" pattern on HRCT and in many patients for whom the HRCT suggests an alternative diagnosis; histopathologic confirmation should be considered in patients demonstrating these patterns whenever feasible.

Interstitial lung diseases in dogs and cats part II: Known cause and other discrete forms.

In addition to idiopathic interstitial pneumonias, interstitial lung diseases (ILDs) can occur secondary to known causes or be classified as discrete syndromes. Also known as diffuse parenchymal lung diseases, the ILDs represent a heterogenous group of non-infectious, non-neoplastic disorders characterized by varied patterns of inflammation and fibrosis. Characteristically associated with the true interstitium (i.e. the anatomic space lined by alveolar epithelial cells and capillary endothelial cells and the loose-binding connective tissue), it is important to understand ILDs are associated with pathology of the distal lung parenchyma and thus lesions can be bronchiolocentric or resemble alveolar filling disorders. Injury to the distal lung can occur via inhalation or hematogenous routes. This review will build on a proposed classification scheme adapted from human medicine to describe known cause and discrete forms of ILDs in dogs and cats.