What every radiologist should know about idiopathic interstitial pneumonias

A 53-year-old man with dyspnoea, respiratory failure, consistent with infliximab-induced acute interstitial pneumonitis after an accelerated induction dosing schedule

A 53-year-old man with ulcerative colitis (UC) suffered fatal acute interstitial pneumonitis (AIP) post completing an accelerated infliximab induction course. This is the first case reported in this setting. A literature review found four similar cases of infliximab-induced interstitial lung disease in the setting of treating patients with UC using standard infliximab regimens had successful treatment of the subjects post infliximab discontinuation. Unfortunately, the patient we are presenting, who had an accelerated infliximab induction course, did not survive. Although a prior small trial along more recent new small studies continue to show a benefit in reducing the need for early colectomy with the accelerated infliximab induction regimen as salvage therapy, it should be used cautiously until more safety data are available. Further larger trials are required to investigate rare side effects that may be associated with this regimen such as rapidly progressive lung toxicity as seen in this patient.

Radio-pathological correlation of organizing pneumonia (OP): a pictorial review

Since the description of cryptogenic organizing pneumonia in 1983 by Davison et al and the subsequent report on bronchiolitis obliterans organizing pneumonia by Epler et al, some reports have been published regarding the imaging features of organizing pneumonia (OP). In this pictorial review, we aimed to describe and illustrate different manifestations of OP on high-resolution CT (HRCT) accompanied by their histopathological correlations for a better comprehension of pathomechanism of the radiological findings. The main HRCT findings in OP include: consolidation, ground-glass opacification, perilobular opacity, reversed halo opacity, nodule or mass, parenchymal bands, bronchial wall thickening, bronchial dilatation, mediastinal lymphadenopathy and pleural effusion. In addition, we discuss the radiological differential diagnosis for each manifestation, as well as imaging evolution during patient follow-up, and two OP-related entities: the possibility of non-specific interstitial pneumonia development following OP and a relatively new rare entity related to OP called acute fibrinous and organizing pneumonia. For radiologists and physicians, a detailed knowledge of the potential radiological manifestations in OP is crucial for making a correct diagnosis and managing the patient properly. Moreover, some unnecessary lung biopsies will be avoided.

Imaging in noncardiovascular thoracic emergencies: a pictorial review

Cardiovascular and noncardiovascular conditions are commonly encountered in the emergency department. While the majority of patients have underlying cardiovascular aetiologies, such as acute myocardial infarction, congestive heart failure, aortic dissection and pulmonary embolism, a small subset of patients have underlying noncardiovascular conditions, although they present with similar symptoms of chest pain, dyspnoea, cough, haemoptysis and haematemesis. This article aims to describe the imaging findings in common noncardiovascular conditions of the chest that are frequently encountered in the emergency department, with a review of the existing literature.

High-resolution computed tomography and magnetic resonance imaging protocols in the diagnosis of fibrotic interstitial lung disease: overview for "non-radiologists"

Fibrotic interstitial lung diseases (ILDs) include a number of pulmonary disorders characterized by infiltration of inflammatory cells in lung parenchyma and fibrosis resulting in decreased lung compliance. Idiopathic pulmonary fibrosis (IPF) represents the most common ILD. ILDs can be divided in two anatomo-pathological and radiographic patterns: usual interstitial pneumonitis (UIP) and non-specific interstitial pneumonitis (NSIP). The different radiological features of UIP and NSIP are discussed. The American Thoracic Society, the European Respiratory Society, the Japanese Respiratory Society, and the Latin American Thoracic Association guidelines for the diagnosis and management of IPF have identified several characteristic high-resolution computed tomography (HRCT) features of UIP. However, even if these guidelines recommend to avoid surgical lung biopsy in case of confident UIP diagnosis on HRCT, they present some limitations, the most important of which is represented by interobserver agreement. Magnetic resonance imaging (MRI) can be considered as a radiation-free alternative to HRCT for several lung diseases. However, the clinical value of MRI for IPF diagnosis remains to be proven. (Sarcoidosis Vasc Diffuse Lung Dis 2017; 34: 300-306).

Imaging Pulmonary Inflammation

Lung inflammatory diseases contribute significantly to the socioeconomic burden of disease. Yet very few new, effective therapies for respiratory disease have been approved for use. A major contributing factor is the lack of biomarkers that can accurately quantify the lung inflammatory burden and can be used to understand the contribution of lung inflammation to loss in lung function. Molecular imaging approaches can detect and quantify the recruitment and activation of specific immune cells in lung inflammation. We review the clinical techniques used to image lung inflammation, provide an overview of clinical and emerging PET techniques for quantifying lung inflammation, and discuss potential clinical applications.

Update on Pulmonary Fibrosis: Not All Fibrosis Is Created Equally

CONTEXT

Three distinct patterns of pulmonary fibrosis, including usual interstitial pneumonia, fibrotic nonspecific interstitial pneumonia, and airway-centered fibrosis, can be identified on surgical lung biopsies.

OBJECTIVES

To compare the pathologic definitions, clinical and radiographic presentations, etiologies and differential diagnoses, treatments, and prognoses of usual interstitial pneumonia, fibrotic nonspecific interstitial pneumonia, and airway-centered fibrosis patterns, and to address the challenges and controversies related to pulmonary fibrosis.

DATA SOURCES

Data were derived from published literature and clinical experience.

CONCLUSIONS

Although there may be overlap, identification of the dominant form of fibrosis in a particular case can provide a general category of disease and assist in identifying an etiology.

Radiographic and Pathologic Manifestations of Uncommon and Rare Pulmonary Lesions

Pulmonary opacities/nodules are common findings on computed tomography examinations, which may represent an underlying infections or malignancy. However, not every pulmonary nodule or opacity represents malignancy or infection. We present a pictorial essay illustrating common as well as obscure noninfectious, nonmalignant pulmonary lesions. Lesions discussed include organizing pneumonia, Langerhans cell histiocytosis, pulmonary amyloidosis, hyalinizing granuloma, tumourlet (benign localized neuroendocrine cell proliferations), atypical alveolar hyperplasia, inflammatory myofibroblastic tumour, papillary alveolar adenoma, plasma cell granuloma, juvenile xanthogranuloma, and sclerosing hemangiomas. We discuss the clinical presentation, prevalence, radiographic clues, pathology, and diagnostic pitfalls of these rare lesions.

State of the art in the diagnosis and management of interstitial lung disease

The interstitial lung diseases (ILDs) are a diverse group of disorders characterized by a varying combination of inflammation and fibrosis of the pulmonary parenchyma. Treatment and prognosis of ILD typically depend on the underlying ILD subtype, highlighting the importance of accurate classification and diagnosis. Besides a thorough history and clinical examination, the protocol should include a 6-minute walk test, chest radiography, high-resolution computed tomography, biochemical analysis, pulmonary function tests, blood gas analysis, bronchoalveolar lavage, and, when necessary, a lung biopsy. The final diagnosis of ILD entities requires dynamic interaction between clinicians, radiologists and pathologists to reach a clinico-radiologic-pathologic diagnosis, the gold standard no longer being the histology but rather a multidisciplinary approach.

Interstitial Lung Change in Pre-radiation Therapy Computed Tomography Is a Risk Factor for Severe Radiation Pneumonitis

PURPOSE

We examined clinical and dosimetric factors as predictors of symptomatic radiation pneumonitis (RP) in lung cancer patients and evaluated the relationship between interstitial lung changes in the pre-radiotherapy (RT) computed tomography (CT) and symptomatic RP.

MATERIALS AND METHODS

Medical records and dose volume histogram data of 60 lung cancer patients from August 2005 to July 2006 were analyzed. All patients were treated with three dimensional (3D) conformal RT of median 56.9 Gy. We assessed the association of symptomatic RP with clinical and dosimetric factors.

RESULTS

With a median follow-up of 15.5 months (range, 6.1 to 40.9 months), Radiation Therapy Oncology Group grade ≥ 2 RP was observed in 14 patients (23.3%). Five patients (8.3%) died from RP. The interstitial changes in the pre-RT chest CT, mean lung dose (MLD), and V30 significantly predicted RP in multivariable analysis (p=0.009, p < 0.001, and p < 0.001, respectively). MLD, V20, V30, and normal tissue complication probability normal tissue complication probability (NTCP) were associated with the RP grade but less so for grade 5 RP. The risk of RP grade ≥ 2, ≥ 3, or ≥ 4 was higher in the patients with interstitial lung change (grade 2, 15.6% to 46.7%, p=0.03; grade 3, 4.4% to 40%, p=0.002; grade 4, 4.4% to 33.3%, p=0.008). Four of the grade 5 RP patients had diffuse interstitial change in pre-RT CT and received chemoradiotherapy.

CONCLUSION

Our study identified diffuse interstitial disease as a significant clinical risk for RP, particularly fatal RP. We showed the usefulness of MLD, V20, V30, and NTCP in predicting the incidence and severity of RP.

[HRCT patterns of the most important interstitial lung diseases]

Interstitial lung diseases are a mixed group of diffuse parenchymal lung diseases which can have an acute or chronic course. Idiopathic diseases and diseases with an underlying cause (e.g. collagen vascular diseases) share the same patterns. Thin section computed tomography (CT) plays a central role in the diagnostic work-up. The article describes the most important interstitial lung diseases following a four pattern approach with a predominant nodular or reticular pattern or a pattern with increased or decreased lung density.

Clinical and radiological features of idiopathic interstitial pneumonias (IIPs): a pictorial review

OBJECTIVES

To illustrate the clinical and radiological features of idiopathic interstitial pneumonias (IIPs), according to the American Thoracic Society (ATS)/European Respiratory Society (ERS) classification updated in 2013.

METHODS

IIPs include a subset of diffuse and restrictive lung diseases, resulting from damage to the parenchyma characterised by inflammation and fibrosis of the interstitium. Classification into major and rare IIPs is based on the 2013 ATS/ERS committee.

RESULTS

The diagnosis of idiopathic pulmonary fibrosis (IPF) needs to exclude other well-known causes of interstitial lung diseases. According to the 2011 evidence-based guidelines, usual interstitial pneumonia (UIP) can be diagnosed by HRCT when all criteria are fulfilled. Non-specific interstitial pneumonia (NSIP) is characterised by patchy ground-glass opacities and irregular linear/reticular opacities. The imaging patterns of respiratory bronchiolitis associated-interstitial lung disease (RB-ILD) and desquamative interstitial pneumonia (DIP) show centrolobular nodules and ground-glass opacities. Cryptogenic organising pneumonia (COP) consists of patchy peripheral or peribronchial consolidations, while ground-glass opacities are typically associated with diffuse lung consolidation, evolving to fibrosis, in acute interstitial pneumonia (AIP). Rare IIPs include lymphoid interstitial pneumonia and idiopathic pleuro-parenchymal fibroelastosis (IPPFE).

CONCLUSIONS

The knowledge of IIP imaging features on HRCT images help radiologists in diagnosis. Moreover, the overlap of imaging features needs a multidisciplinary approach.

TEACHING POINTS

• UIP findings are reticulations, bronchiectasis, honeycombing and absence of inconsistent features. • Bilateral patchy ground-glass areas represent the most encountered features in NSIP. • Poorly defined centrilobular nodules are typical of RB-ILD, whereas a ground-glass appearance is typical of DIP. • HRCT features of COP include characteristic peripheral or peribronchial patchy consolidations. • Rare IIPs include idiopathic LIP and idiopathic pleuro-parenchymal fibroelastosis (PPFE).

[Granulomatous lung and systemic diseases]

Granuloma formation occurs in the human body if there is a particle which persists in phagocytes and which the immune system cannot eliminate. The immune reaction of granuloma formation evolved in order to combat mycobacteria with the aim of localizing mycobacteria and to avoid spreading of mycobacteria throughout the body. Granulomatous lung diseases are often accompanied by severe, systemic inflammation. However, acute phase proteins may be only slightly elevated. The spectrum of granulomatous lung diseases is broad. Sarcoidosis is the most common granulomatous lung disease. To diagnose sarcoidosis, other infectious granulomatous lung diseases such as tuberculosis, atypical mycobacterial and fungal infection have to be ruled out. Pulmonary granuloma also evolve in the context of autoimmune diseases such as rheumatoid arthritis, granulomatosis with polyangiitis (GBA, Wegener's) and eosinophilic granulomatosis with polyangiitis (EGPA, Churg-Strauss syndrome). Furthermore, immunodeficiencies such as common variable immunodeficiency (CVID) and immune reconstitution syndrome in HIV can be associated with systemic granulomatous inflammation. Finally, occupational lung disease, particularly hypersensitivity pneumonitis, silicosis, hard metal lung, and chronic berylliosis are associated with pulmonary granuloma formation.

Multiple lung parenchymal abnormalities: Don't panic, let's be pragmatic! The 6 question rule - a checklist strategy

Analysis of multiple lung parenchymal abnormalities on HRCT is a real diagnostic challenge. These abnormalities may be due to a disease of the pulmonary interstitial tissue, the bronchial tree, the cardiovascular system or to abnormal alveolar filling with fluid, blood, cells or tumor, several of these etiologies possibly being concomitant. Systematic pathophysiological reasoning, in the form of a logical checklist, guides reflection and covers many of the most frequent diagnoses and potentially treatable emergencies that can be identified by the non-specialist radiologist. This approach also provides a basis for deepening knowledge of each area. The use of the mnemonic FIBROVAKIM (fibrosis-bronchi-vascular-cancer-infection-medication) is easy to apply and summarizes this strategy.

Quantitative computed tomography imaging of interstitial lung diseases

PURPOSE

High-resolution chest computed tomography (HRCT) is essential in the characterization of interstitial lung disease. The HRCT features of some diseases can be diagnostic. Longitudinal monitoring with HRCT can assess progression of interstitial lung disease; however, subtle changes in the volume and character of abnormalities can be difficult to assess. Accuracy of diagnosis can be dependent on expertise and experience of the radiologist, pathologist, or clinician. Quantitative analysis of thoracic HRCT has the potential to determine the extent of disease reproducibly, classify the types of abnormalities, and automate the diagnostic process.

MATERIALS AND METHODS

Novel software that utilizes histogram signatures to characterize pulmonary parenchyma was used to analyze chest HRCT data, including retrospective processing of clinical CT scans and research data from the Lung Tissue Research Consortium. Additional information including physiological, pathologic, and semiquantitative radiologist assessment was available to allow comparison of quantitative results, with visual estimates of the disease, physiological parameters, and measures of disease outcome.

RESULTS

Quantitative analysis results were provided in regional volumetric quantities for statistical analysis and a graphical representation. These results suggest that quantitative HRCT analysis can serve as a biomarker with physiological, pathologic, and prognostic significance.

CONCLUSIONS

It is likely that quantitative analysis of HRCT can be used in clinical practice as a means to aid in identifying a probable diagnosis, stratifying prognosis in early disease, and consistently determining progression of the disease or response to therapy. Further optimization of quantitative techniques and longitudinal analysis of well-characterized subjects would be helpful in validating these methods.

Expiratory CT scan in patients with normal inspiratory CT scan: a finding of obliterative bronchiolitis and other causes of bronchiolar obstruction

Expiratory CT scan is usually obtained as supplement to normal inspiratory CT scan to recognize air-trapping, which is expression of small airways obstruction. In some patients the air-trapping may be the only sign of an early-stage small airways disease in an otherwise normal lung.

The purpose of this article is to illustrate pathologic conditions, namely obliterative bronchiolitis, in which expiratory CT scan can be abnormal despite normal inspiratory CT examination, and to highlight indications for this technique in patients with clinical and functional suspect of bronchiolar obstruction.

Usual interstitial pneumonia-pattern fibrosis in surgical lung biopsies. Clinical, radiological and histopathological clues to aetiology

Pulmonary fibrosis in surgical lung biopsies is said to have a 'usual interstitial pneumonia-pattern' (UIP-pattern) of disease when scarring of the parenchyma is present in a patchy, 'temporally heterogeneous' distribution. These biopsies are one of the more common non-neoplastic specimens surgical pathologists encounter and often pose a number of challenges. UIP is the expected histopathological pattern in patients with clinical idiopathic pulmonary fibrosis (IPF), but the UIP-pattern can be seen in other conditions on occasion. Most important among these are the rheumatic interstitial lung diseases (RILD) and chronic hypersensitivity pneumonitis (CHrHP). Because theses entities have different mechanisms of injury, approach to therapy, and expected clinical progression, it is imperative for the surgical pathologist to correctly classify them. Taken in isolation, the UIP-pattern seen in patients with IPF may appear to overlap with that of RILD and CHrHP, at least when using the broadest definition of this term (patchy fibrosis). However, important distinguishing features are nearly always present in our experience, and the addition of a multidisciplinary approach will often resolve the critical differences between these diseases. In this manuscript, we review the distinguishing clinical, radiologic and histopathological features of UIP of IPF, RILD and CHrHP, based, in part, on the existing literature, but also lessons learned from a busy lung biopsy consultation practice.

A practical approach to high-resolution CT of diffuse lung disease

Diffuse lung disease presents a variety of high-resolution CT findings reflecting its complex pathology, and provides diagnostic challenge to radiologists. Frequent modification of detailed pathological classification makes it difficult to keep up with the latest understanding. In this review, we describe a practical approach to high-resolution CT diagnosis of diffuse lung disease, emphasizing (1) analysis of "distribution" of the abnormalities, (2) interpretation of "pattern" in relation to distribution, (3) utilization of associated imaging findings and clinical information, and (4) chronicity of the findings. This practical approach will help radiologists establish a way to interpret high-resolution CT, leading to pin-point diagnosis or narrower differential diagnoses of diffuse lung diseases.

Comparative manifestations and diagnostic accuracy of high-resolution computed tomography in usual interstitial pneumonia and nonspecific interstitial pneumonia

PURPOSE OF REVIEW

Of the idiopathic interstitial pneumonias, the differentiation between idiopathic pulmonary fibrosis (IPF) and nonspecific interstitial pneumonitis (NSIP) raises considerable diagnostic challenges, as their clinical presentations share many overlapping features. IPF is a fibrosing pneumonia of unknown cause, showing a histologic pattern of usual interstitial pneumonia (UIP), and has a poorer prognosis than does NSIP. This review examines whether the radiographic features of IFP and NSIP as assessed by high-resolution computed tomography (HRCT) can be used to distinguish between these two entities.

RECENT FINDINGS

The diagnostic accuracy of HRCT for UIP and NSIP has been reported to be approximately 70% in various studies. Disagreement between the HRCT diagnosis and the histologic diagnosis occurs in approximately one-third of the cases. The predominant feature of honeycombing on HRCT yields a specificity of approximately 95% and sensitivity of approximately 40% for UIP. In contrast, a predominant feature of ground glass opacities (GGOs) gives a sensitivity of approximately 95% and specificity of approximately 40% for NSIP.

SUMMARY

The finding of honeycombing as the predominant HRCT feature suggests the diagnosis of UIP and may exclude the need for biopsy. Predominant features of GGOs are not specific enough to distinguish between NSIP and UIP.

Sorafenib-induced acute interstitial pneumonia in patients with advanced hepatocellular carcinoma: report of three cases

Little is known about acute interstitial pneumonia (AIP) induced by sorafenib therapy in patients with advanced hepatocellular carcinoma (HCC). Here, we present three patients with advanced HCC who developed AIP during sorafenib therapy, with fatal complications in two cases. Case 1 was a 76-year-old man who developed dyspnea. Chest CT showed interstitial pneumonia. Sorafenib was discontinued immediately, and prednisolone was started. His pneumonia resolved. A drug-induced lymphocyte stimulation test for sorafenib was positive. Case 2 was a 75-year-old man and case 3 was a 77-year-old man, both of whom developed high-grade fever and hypoxemia during sorafenib therapy, and were diagnosed with AIP. In spite of high-dose steroid therapy, their respiratory failure worsened and both patients died. In all three cases, serum KL-6 or surfactant protein D concentrations were elevated, and blood and sputum cultures did not grow pathogens. All three patients were smokers with restrictive lung disease on preoperative respiratory function testing, but did not have respiratory symptoms before sorafenib therapy. The clinical features of these three cases suggest that male gender, older age, smoking history, and lung disease are associated with acute sorafenib-induced AIP in patients with advanced HCC.

Natural history of honeycombing: follow-up of patients with idiopathic pulmonary fibrosis treated with single-lung transplantation

PURPOSE

Although honeycombing is one of the key features for the diagnosis of idiopathic pulmonary fibrosis (IPF), its origin and evolution are still poorly understood. The aim of our study was to analyse the natural history of honeycombing in patients treated with single-lung transplantation.

MATERIALS AND METHODS

We considered seven patients who underwent single-lung transplantation; two of them (28.6%) were excluded from our analysis because they died in the posttransplantation period, whereas the remaining five (71.4%) were evaluated with computed tomography (CT) over 67.6±38.56 months. Each CT scan was assessed for disease extension and cyst size (visual score and size of target cysts); CT scans acquired after 2006 were also assessed for native lung volume.

RESULTS

All patients showed disease progression (with a concurrent reduction in lung volume in two, 40%) and a progression of honeycombing, with increased number and size of cysts in four (80%). We observed dimensional changes in all target cysts (enlargement or reduction); three patients (60%) also had radiological evidence of complications, such as spontaneous rupture with pneumothorax and development of mycetomas within the cysts.

CONCLUSIONS

Honeycombing is a dynamic process in which the overall trend is represented by a dimensional increase in cystic pattern; however, single cysts may have a different evolution (enlargement, reduction or complications). This behaviour could be explained by the variety of the pathogenetic processes underlying honeycombing, with cysts that may present abnormal communication with the airway, including the development of a check-valve mechanism.

Smoking and idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a disease of unknown etiology with considerable morbidity and mortality. Cigarette smoking is one of the most recognized risk factors for development of IPF. Furthermore, recent work suggests that smoking may have a detrimental effect on survival of patients with IPF. The mechanism by which smoking may contribute to the pathogenesis of IPF is largely unknown. However, accumulating evidence suggests that increased oxidative stress might promote disease progression in IPF patients who are current and former smokers. In this review, potential mechanisms by which cigarette smoking affects IPF, the effects of cigarette smoking on accelerated loss of lung function in patients with IPF, key genetic studies evaluating the potential candidate genes and gene-environment (smoking) interaction, diagnosis, and treatment with emphasis on recently closed and ongoing clinical trials are presented.

Smoking-related interstitial lung diseases

Cigarette smoke, a toxic collection of thousands of chemicals generated from combustion of tobacco, is recognized as the primary causative agent of certain diffuse interstitial and bronchiolar lung diseases. Most patients afflicted with these disorders are cigarette smokers, and smoking cessation has been shown to be capable of inducing disease remission and should occupy a pivotal role in the management of all smokers with these diffuse lung diseases. The role of pharmacotherapy with corticosteroids or other immunomodulating agents is not well established but may be considered in patients with progressive forms of smoking-related interstitial lung diseases.

[Radiological diagnostic approach to idiopathic interstitial pneumonias: findings in high resolution computed tomography]

A review is presented on the histological and radiological findings in idiopathic interstitial pneumonias, which are included among the diffuse parenchymal lung diseases. Although they may affect other compartments, the lung interstitium is the initial substrate of the parenchymal lesion due to different patterns of inflammation and fibrosis. The current classification, proposed in 2002 as an international multidisciplinary consensus document promoted by the American Thoracic Society and the European Respiratory Society, includes 7 conditions. Based on histological criteria, each histological pattern is associated with an image pattern. They are a group of conditions of unknown origin with common characteristics and differential features that enable them to be individualised as diseases with a different prognosis and treatment. They are rare as idiopathic forms, but share a morphological substrate with other more common diseases of unknown cause, which means they have to be excluded to reach a definitive diagnosis. For this reason it is important that the radiologist is familiar with their characteristic imaging findings.

Comparison of usual interstitial pneumonia and nonspecific interstitial pneumonia: quantification of disease severity and discrimination between two diseases on HRCT using a texture-based automated system

Objective

To evaluate the usefulness of an automated system for quantification and discrimination of usual interstitial pneumonia (UIP) and nonspecific interstitial pneumonia (NSIP).

Materials and Methods

An automated system to quantify six regional high-resolution CT (HRCT) patterns: normal, NL; ground-glass opacity, GGO; reticular opacity, RO; honeycombing, HC; emphysema, EMPH; and consolidation, CONS, was developed using texture and shape features. Fifty-four patients with pathologically proven UIP (n = 26) and pathologically proven NSIP (n = 28) were included as part of this study. Inter-observer agreement in measuring the extent of each HRCT pattern between the system and two thoracic radiologists were assessed in 26 randomly selected subsets using an interclass correlation coefficient (ICC). A linear regression analysis was used to assess the contribution of each disease pattern to the pulmonary function test parameters. The discriminating capacity of the system between UIP and NSIP was evaluated using a binomial logistic regression.

Results

The overall ICC showed acceptable agreement among the system and the two radiologists (r = 0.895 for the abnormal lung volume fraction, 0.706 for the fibrosis fraction, 0.895 for NL, 0.625 for GGO, 0.626 for RO, 0.893 for HC, 0.800 for EMPH, and 0.430 for CONS). The volumes of NL, GGO, RO, and EMPH contribute to forced expiratory volume during one second (FEV₁) (r = 0.72, β values, 0.84, 0.34, 0.34 and 0.24, respectively) and forced vital capacity (FVC) (r = 0.76, β values, 0.82, 0.28, 0.21 and 0.34, respectively). For diffusing capacity (DL_co), the volumes of NL and HC were independent contributors in opposite directions (r = 0.65, β values, 0.64, -0.21, respectively). The automated system can help discriminate between UIP and NSIP with an accuracy of 82%.

Conclusion

The automated quantification system of regional HRCT patterns can be useful in the assessment of disease severity and may provide reliable agreement with the radiologists' results. In addition, this system may be useful in differentiating between UIP and NSIP.

Fibrotic idiopathic interstitial pneumonias: HRCT findings that predict mortality

OBJECTIVES

The study aims were to identify CT features that predict outcome of fibrotic idiopathic interstitial pneumonia (IIP) when information from lung biopsy data is unavailable.

METHODS

HRCTs of 146 consecutive patients presenting with fibrotic IIP were studied. Visual estimates were made of the extent of abnormal lung and proportional contribution of fine and coarse reticulation, microcystic (cysts ≤4 mm) and macrocystic honeycombing. A score for severity of traction bronchiectasis was also assigned. Using death as our primary outcome measure, variables were analysed using the Cox proportional hazards model.

RESULTS

CT features predictive of a worse outcome were coarse reticulation, microcystic and macrocystic honeycombing, as well as overall extent of lung abnormality (p < 0.001). Importantly, increased severity of traction bronchiectasis, corrected for extent of parenchymal abnormality, was predictive of poor prognosis regardless of the background pattern of abnormal lung (HR = 1.04, CI = 1.03-1.06, p < 0.001). On bivariate Cox analysis microcystic honeycombing was a more powerful determinant of a poor prognosis than macrocystic honeycombing.

CONCLUSIONS

In fibrotic IIPs we have shown that increasingly severe traction bronchiectasis is indicative of higher mortality irrespective of the HRCT pattern and extent of disease. Extent of microcystic honeycombing is a more powerful determinant of outcome than macrocystic honeycombing.

Computer-aided diagnosis of pulmonary infections using texture analysis and support vector machine classification

RATIONALE AND OBJECTIVES

The purpose of this study was to develop and test a computer-assisted detection method for the identification and measurement of pulmonary abnormalities on chest computed tomographic (CT) imaging in cases of infection, such as novel H1N1 influenza. The method developed could be a potentially useful tool for classifying and quantifying pulmonary infectious disease on CT imaging.

MATERIALS AND METHODS

Forty chest CT examinations were studied using texture analysis and support vector machine classification to differentiate normal from abnormal lung regions on CT imaging, including 10 patients with immunohistochemistry-proven infection, 10 normal controls, and 20 patients with fibrosis.

RESULTS

Statistically significant differences in the receiver-operating characteristic curves for detecting abnormal regions in H1N1 infection were obtained between normal lung and regions of fibrosis, with significant differences in texture features of different infections. These differences enabled the quantification of abnormal lung volumes on CT imaging.

CONCLUSION

Texture analysis and support vector machine classification can distinguish between areas of abnormality in acute infection and areas of chronic fibrosis, differentiate lesions having consolidative and ground-glass appearances, and quantify those texture features to increase the precision of CT scoring as a potential tool for measuring disease progression and severity.

Multi-technique imaging of sarcoidosis

Sarcoidosis is a multisystem granulomatous disorder of unknown aetiology. The diagnosis is suggested on the basis of wide ranging clinical and radiological manifestations, and is supported by the histological demonstration of non-caseating granulomas in affected tissues. This review highlights the multisystem radiological features of the disease across a variety of imaging methods including multidetector computed tomography (CT), magnetic resonance imaging (MRI) as well as functional radionuclide techniques, particularly 2-[(18)F]-fluoro-2-deoxy-d-glucose (FDG) positron emission tomography/computed tomography (PET/CT). It is important for the radiologist to be aware of the varied radiological manifestations of sarcoidosis in order to recognize and suggest the diagnosis in the appropriate clinical setting.

Thoracic manifestations of primary humoral immunodeficiency: a comprehensive review

Humoral immunodeficiencies, which are characterized by defective production of antibodies, are the most common types of primary immunodeficiency. Pulmonary changes are present in as many as 60% of patients with humoral immunodeficiency. Chronic changes and recurrent infections in the respiratory airways are the main causes of morbidity and mortality in those affected by a humoral immunodeficiency. Medical imaging, especially computed tomography (CT), plays a crucial role in the initial detection and characterization of changes and in monitoring the response to therapy. The spectrum of abnormalities seen at thoracic imaging includes noninfectious airway disorders, infections, chronic lung diseases, chronic inflammatory conditions (granulomatosis, interstitial pneumonias), and benign and malignant neoplasms. Recognition of characteristic CT and radiographic features, and correlation of those features with clinical and laboratory findings, are necessary to differentiate between the many possible causes of parenchymal and mediastinal disease seen in patients with primary humoral immunodeficiencies.

Biopsy-proved idiopathic pulmonary fibrosis: spectrum of nondiagnostic thin-section CT diagnoses

PURPOSE

To document the spectrum of misleading thin-section computed tomographic (CT) diagnoses in patients with biopsy-proved idiopathic pulmonary fibrosis (IPF).

MATERIALS AND METHODS

This study had institutional review board approval, and patient consent was not required. Three observers, blinded to any clinical information and the purpose of the study, recorded thin-section CT differential diagnoses and assigned a percentage likelihood to each for a group of 123 patients (79 men, 44 women; age range, 27-82 years) with various chronic interstitial lung diseases, including a core group of 55 biopsy-proved cases of IPF. Patients with IPF in the core group, in whom IPF was diagnosed as low-grade probability (<30%) by at least two observers, were considered to have atypical IPF cases, and the alternative diagnoses were analyzed further.

RESULTS

Thirty-four (62%) of 55 biopsy-proved IPF cases were regarded as alternative diagnoses. In these atypical IPF cases, the first-choice diagnoses, expressed with high degree of probability, were nonspecific interstitial pneumonia (NSIP; 18 [53%] of 34), chronic hypersensitivity pneumonitis (HP; four [12%] of 34), sarcoidosis (three [9%] of 34), and organizing pneumonia (one [3%] of 34); in eight (23%) of 34 cases, no single diagnosis was favored by more than one observer. Frequent differential diagnoses, although not always the first-choice diagnosis, were NSIP (n = 29), chronic HP (n = 23), and sarcoidosis (n = 9).

CONCLUSION

In the correct clinical setting, a diagnosis of IPF is not excluded by thin-section CT appearances more suggestive of NSIP, chronic HP, or sarcoidosis. (c) RSNA, 2010.

High-resolution computed tomography in the diagnosis and follow-up of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is the most common interstitial lung disease and is associated with a fatal prognosis. Familiarity with the typical appearances of IPF on high-resolution computed tomography (HRCT) is important, as in the appropriate clinical setting, it is often sufficient for establishing a confident diagnosis of IPF without the need for surgical biopsy. Moreover, HRCT can provide important prognostic information in IPF. This is noteworthy, as the course of IPF is variable, and many patients develop complications leading to respiratory failure and death. The purpose of this paper is to review the progress made towards a better understanding of the HRCT patterns of IPF.

[Idiopathic pulmonary fibrosis]

Idiopathic pulmonary fibrosis is the most common of the idiopathic interstitial pneumonias. It occurs more often in men than in women and in those older than 65 years than in younger people. It is strongly associated with smoking. Diffuse crackles at auscultation and computed tomographic features of reticulation and honeycombing are major elements of diagnosis. The concept of epithelial-mesenchymal cell transition has recently received much attention; this transition appears to play a greater role in the pathogenesis than inflammation. The recently identified syndrome of combined pulmonary fibrosis and emphysema is characterized by relatively preserved lung volumes and flows contrasting with severely impaired carbon monoxide transfer, major exercise hypoxemia, and an elevated prevalence of pulmonary hypertension. Disease exacerbations contribute to deterioration and to death. There is no effective treatment for this disease. Median survival is about 2-3 years after diagnosis.

Rituximab (B-cell depleting antibody) associated lung injury (RALI): a pediatric case and systematic review of the literature

INTRODUCTION

Pulmonary toxicity of delayed onset is a rare complication of B-lymphocyte depleting antibody therapy and has been almost exclusively reported in older patients with B-cell malignancies.

AIMS

To describe a pediatric patient with rituximab-associated lung injury (RALI), to systematically analyze previous reports of pulmonary complications, and to summarize common clinico-pathological features, treatment, and outcome.

RESULTS

A teenage boy with focal segmental glomerulosclerosis (FSGS) presented with progressive dyspnea, fever, hypoxemia and fatigue 18 days after the completion of a second course of rituximab infusions for calcineurin inhibitor-dependent nephrotic syndrome. Respiratory symptoms started while he received high-dose prednisone for persistent proteinuria. Bilateral, diffuse ground-glass infiltrates corresponded to the presence of inflammatory cells in the bronchioalveolar lavage fluid. Empiric antibiotic treatment including clarithromycin was given, but the microbiological work-up remained negative. Serum IgE, C3, and C4 concentrations were normal. He recovered within 3 weeks after onset.We systematically reviewed 23 reports describing 30 additional cases of rituximab-associated lung disease. Twenty eight patients had received rituximab for B-cell malignancies, one for graft-versus-host disease and one for immune thrombocytopenia. Median age was 64 years (interquartile range [IQR] 58-69 years). Seventy one percent received concomitant chemotherapy. Time to onset from the last rituximab dose was 14 days (IQR 11-22 days). Eleven of 31 patients required mechanical ventilation, and 9 died (29%). Ventilation was a significant predictor of fatal outcome (odds ratio 46.7; confidence interval 9.5-229.9). High dose glucocorticoid therapy did not improve survival or prevent severe lung disease or death.

CONCLUSIONS

With the expanding use of rituximab for novel indications, additional cases of RALI affecting younger age groups are expected to emerge. Mechanical ventilation predicts poor outcome. Glucocorticoids may not be protective.

High resolution computed tomography in idiopathic interstitial pneumonias

In June 2001, using an "international multidisciplinary consensus," the American Thoracic Society and European Respiratory Society classified the idiopathic interstitial pneumonias (Am J Respir Crit Care Med 2002;165:277-304). The American Thoracic Society and European Respiratory Society coined the term idiopathic interstitial pneumonias because the diseases in question have both unknown etiologies and various combinations of inflammation and fibrosis within the lung parenchyma. The consensus included the development of a classification standard of the interstitial pneumonias and discussed the role of surgical lung biopsy and bronchoalveolar lavage evaluation. The classification of idiopathic interstitial pneumonias is based on histologic criteria, which correlate to imaging patterns on high-resolution computed tomography. The group of lung diseases under the umbrella of idiopathic interstitial pneumonias includes the following: usual interstitial pneumonia, nonspecific interstitial pneumonia, desquamative interstitial pneumonia, respiratory bronchiolitis interstitial lung disease, acute interstitial pneumonia, cryptogenic organizing pneumonia, and lymphoid interstitial pneumonia.