Padrões tomográficos das doenças intersticiais pulmonares difusas com correlação clínica e patológica

Improving Accessibility to Patients with Interstitial Lung Disease (ILD): Barriers to Early Diagnosis and Timely Treatment in Latin America

Delayed initiation of effective antifibrotic therapy in patients with interstitial lung diseases (ILD) may influence the progression and outcome of the disease. This study analyzes the differences in the journey of patients with ILD in the Brazilian and Mexican health systems. An evaluative study was conducted in reference centers for interstitial lung diseases in Brazil and Mexico with a panel of four specialists. The patient's journey in both countries begins when the patient seeks medical care after observing a chronic respiratory symptom. In both countries, due to diagnostic complexity, these patients arrive at ILD referral centers at an advanced stage of the disease. Once diagnosis is established, the treatment onset differs between Mexico and Brazil. In Brazil, access to antifibrotic drugs through the public health system has been a significant challenge, and their cost makes them unaffordable for most people. This situation forces medical specialists to provide only supportive care to patients until these drugs can be accessed. In Mexico, antifibrotics have been available in health sectors since 2018. Brazil and Mexico have several similarities regarding the initial journey of the patient due to diagnosis difficulties. Still, the outcome tends to be different due to a difference in access to treatment with antifibrotics. For this reason, advancing health policies that ensure proper treatment for patients with ILD is crucial for the sustainability and reliability of the health system.

An Analysis of Image Features Extracted by CNNs to Design Classification Models for COVID-19 and Non-COVID-19

The SARS-CoV-2 virus causes a respiratory disease in humans, known as COVID-19. The confirmatory diagnostic of this disease occurs through the real-time reverse transcription and polymerase chain reaction test (RT-qPCR). However, the period of obtaining the results limits the application of the mass test. Thus, chest X-ray computed tomography (CT) images are analyzed to help diagnose the disease. However, during an outbreak of a disease that causes respiratory problems, radiologists may be overwhelmed with analyzing medical images. In the literature, some studies used feature extraction techniques based on CNNs, with classification models to identify COVID-19 and non-COVID-19. This work compare the performance of applying pre-trained CNNs in conjunction with classification methods based on machine learning algorithms. The main objective is to analyze the impact of the features extracted by CNNs, in the construction of models to classify COVID-19 and non-COVID-19. A SARS-CoV-2 CT data-set is used in experimental tests. The CNNs implemented are visual geometry group (VGG-16 and VGG-19), inception V3 (IV3), and EfficientNet-B0 (EB0). The classification methods were k-nearest neighbor (KNN), support vector machine (SVM), and explainable deep neural networks (xDNN). In the experiments, the best results were obtained by the EfficientNet model used to extract data and the SVM with an RBF kernel. This approach achieved an average performance of 0.9856 in the precision macro, 0.9853 in the sensitivity macro, 0.9853 in the specificity macro, and 0.9853 in the F1 score macro.

Fish Oil Nanoemulsion Supplementation Attenuates Bleomycin-Induced Pulmonary Fibrosis BALB/c Mice

Diets rich in omega-3 or -6 fatty acids will produce different profiles for cell membranes phospholipid constitutions. Omegas 3 and 6 are part of the diet and can modulate the inflammatory profile. We evaluated the effects of the oral absorption of fish oil, when associated with a lipid nanoemulsion in an experimental pulmonary inflammatory model. Pulmonary fibrosis is a disease associated with excessive extracellular matrix deposition. We determined to investigate the morphophysiological mechanisms in mice that were pretreated after induction with bleomycin (BLM). The pretreatment was for 21 days with saline solution, sunflower oil (SO), fish oil (FO), and fish oil nanoemulsion (NEW3). The animals received a daily dose of 50 mg/Kg of docosahexaenoic acid DHA and 10 mg/Kg eicosapentaenoic (EPA) (100 mg/Kg), represented by a daily dose of 40 µL of NEW3. The blank group was treated with the same amount daily (40 µL) during the 21 days of pretreatment. The animals were treated with SO and FO, 100 mg/Kg (containing 58 mg/Kg of polyunsaturated fats/higher% linoleic acid) and 100 mg/Kg (50 mg/Kg of DHA and 10 mg/Kg EPA), respectively. A single dose of 5 mg/mL (50 μL) bleomycin sulfate, by the intratracheal surgical method in BALB/cAnNTac (BALB/c). NEW3 significantly reduced fibrotic progression, which can be evidenced by the protection from loss of body mass, increase in respiratory incursions per minute, decreased spacing of alveolar septa, decreased severity of fibrosis, and changes in the respiratory system. NEW3 attenuated the inflammatory changes developed in the experimental model of pulmonary fibrosis, while group SO showed a significant increase in inflammatory changes. This concluded that the presented results demonstrated that is possible to positively modulate the immune and inflamamtory response to an external agressor, by changing the nutitional intake of specific fatty acids, such as omega-3 placed in fish oil. Moreover, these benefits can be improved by the nanoencapsulation of fish oil in lipid nanoemulsions.

Development and evaluation of a computer-based decision support system for diffuse lung diseases at high-resolution computed tomography

BACKGROUND

High-resolution computed tomography (HRCT) is essential in narrowing the possible differential diagnoses of diffuse and interstitial lung diseases.

PURPOSE

To investigate the value of a novel computer-based decision support system (CDSS) for facilitating diagnosis of diffuse lung diseases at HRCT.

MATERIAL AND METHODS

A CDSS was developed that includes about 100 different illustrations of the most common HRCT signs and patterns and describes the corresponding pathologies in detail. The logical set-up of the software facilitates a structured evaluation. By selecting one or more CT patterns, the program generates a ranked list of the most likely differential diagnoses. Three independent and blinded radiology residents initially evaluated 40 cases with different lung diseases alone; after at least 12 weeks, observers re-evaluated all cases using the CDSS.

RESULTS

In 40 patients, a total of 113 HRCT patterns were evaluated. The percentage of correctly classified patterns was higher with CDSS (96.8%) compared to assessment without CDSS (90.3%; P < 0.01). Moreover, the percentage of correct diagnosis (81.7% vs. 64.2%) and differential diagnoses (89.2% vs. 38.3%) were superior with CDSS compared to evaluation without CDSS (both P < 0.01).

CONCLUSION

Addition of a CDSS using a structured approach providing explanations of typical HRCT patterns and graphical illustrations significantly improved the performance of trainees in characterizing and correctly identifying diffuse lung diseases.

Sjogren's Syndrome and Pulmonary Disease

Sjogren's syndrome is an autoimmune connective tissue disease targeting the exocrine glands and frequently affecting the respiratory system. The pulmonary disease is the most important extra-glandular manifestation as it carries most of the morbidity and mortality. Typically, it affects the small airways ranging from mild to severe respiratory symptoms. The upper airways are also commonly involved, predisposing sinusitis to occur more frequently than in the normal population. Lymphocytic interstitial pneumonia was initially thought to be the prevailing parenchymal disease; however, multiple cohorts report non-interstitial pneumonia to be the most frequent subtype of interstitial lung disease. In the review of high-resolution computed tomography scans, cystic lesions are commonly found and associate with both the small airways and parenchymal disease. Under their presence, amyloidosis or lymphomas should be considered in the differential. Overall, Sjogren's syndrome has a higher risk for lymphoma, and in lungs this condition should be thought of, especially when the images reveal pulmonary nodularity, lymphocytic interstitial pneumonia and lymphadenopathy. Although, pulmonary artery hypertension was traditionally and exceptionally linked with Sjogren's syndrome, together with systemic lupus erythematosus, they are now acknowledged to be the most common pulmonary vascular disease in east Asian populations, even over patients with systemic sclerosis. Although there are no controlled prospective trials to treat pulmonary disease in Sjogren's syndrome, the mainstay treatment modality still falls on glucocorticoid therapy (systemic and inhaled), combined with immune modulators or alone. Most of the evidence sustains successful outcomes based on reported cases or case series.

Investigation of high-resolution computed tomographic (HRCT) outcomes associated with chronic pulmonary microaspiration (CPM) in Tehran and Zahedan, Iran

Background

In patients with chronic pulmonary microaspiration (CPM) the recognition of high-resolution computed tomographic (HRCT) findings and their pattern is important.

Objective

To investigate the HRCT detections in patients with CPM.

Materials and Methods

This descriptive study enrolled 100 consecutive patients with CPM underwent HRCT of the lungs between 2017 and 2018 in Tehran and Zahedan Hospitals and private centers. The required variables were recorded for each patient with a questionnaire. Subsequently, HRCT was performed and abnormalities were then reported by two radiologists.

Results

Most of patients exhibited bronchial thickening in 33.6% of cases, followed by ground-glass opacity (12.4%), emphysema (11.1%), and bronchiectasis (8.5%). In addition, the most common HRCT findings were found in left lower lobe (LLL) (37.1%), followed by right lower lobe (RLL) (35.9 %), right upper lobe (RUL) (6,2%), and left upper lobe (LUL) (6%).

Conclusion

Our data showed the most common findings in HRCT were bronchial thickening ground-glass opacity, emphysema, and bronchiectasis, where these findings was dominantly found in LLL, RLL, RUL, and LUL, indicating its high tendency to dependent areas.

Diagnostic Accuracy of Multidetector CT in Detection of Early Interstitial Lung Disease With Its Role in Characterization

Background

Multidetector CT (MDCT) has emerged as a useful option for early diagnosis of interstitial lung disease (ILD) with adequate accuracy.

Methods

A total of 80 patients with restricted pulmonary functions and clinical suspicion of ILD were enrolled in the study. MDCT evaluation was done using Siemens Somatom Force 384 slice multidetector computer tomography machine. Pattern analysis for reticular opacities, nodules and lung opacities was done to reach at a diagnosis. Final diagnosis was based on correlation of radiological and clinicopathological findings. Diagnostic efficacy of MDCT was evaluated in terms of sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy for detection of ILD.

Results

Mean age of patients was 58 ± 8.75 years. Majority were females (51.3%). History of chronic obstructive pulmonary disease (COPD), tuberculosis and bronchial asthma was revealed in 31 (38.8%), 26 (32.5%) and 16 (20%) patients, respectively. There were 30 (37.5%) patients having no history of respiratory diseases. MDCT diagnosed ILD in 45 (56.3%) cases. On final diagnosis, ILD was diagnosed in 35 (43.8%) cases (15 usual interstitial pneumonia [UIP], 9 cryptogenic organizing pneumonia [COP], 8 nonspecific interstitial pneumonia [NSIP] and 3 respiratory bronchiolitis associated interstitial lung disease [RBILD]). The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of MDCT in detection of ILD was 91.4%, 71.1%, 71.1%, 91.4% and 80%, respectively.

Conclusion

MDCT as a single modality had a high sensitivity for detection of ILD and could be recommended as first line diagnostic imaging technique.

ChILD: A Pictorial Review of Pulmonary Imaging Findings in Childhood Interstitial Lung Diseases

Childhood interstitial lung disease (chILD) is a group of lung disorders characterized by lung remodeling leading to abnormal gas exchange. ChILD is classified differently from adult interstitial lung disease and encompasses 2 broad categories: "disorders more prevalent in infancy" (<2 years) and "disorders not specific to infancy" (>2 years). High-resolution computed tomography can play an important role in the evaluation of chILD by narrowing the differential diagnosis and preventing unnecessary invasive procedures if typical imaging patterns are recognized. Thus, the pediatric radiologist should consider chILD in children with respiratory distress and identify the imaging patterns to suggest the diagnosis.

Interobserver variability in high-resolution CT of the lungs

Purpose

To quantify the interobserver variability among the most frequently encountered parenchymal patterns in High Resolution CT (HRCT) and to compare the interobserver variability in the application of the 2011 and 2018 usual interstitial pneumonia (UIP) criteria according to the joint guidelines from international thoracic and respiratory societies.

Material and methods

Two observers independently evaluated 126 HRCT, with examples of most common parenchymal patterns, and noted the presence of each pattern. The readers also noted whether the findings met the 2011 criteria for UIP. In a second reading, the same readers noted whether the HRCT met the UIP criteria according to the 2018 UIP update.

Results

The kappa values for interobserver variability for the different patterns ranged from 0.28 (intralobular lines) to 0.85 (tree-in-bud nodules). The kappa value for UIP pattern was similar for 2011 and 2018 criteria, 0.58 and 0.69, respectively. Compared to the 2011 UIP criteria, there was no statistically significant difference in the number of HRCT classified as UIP using the 2018 criteria.

Conclusions

There is a substantial variation in interobserver agreement between the different parenchymal patterns, which suggests that some patterns a more easily identified than others. There is also a considerable reader variation in the assessment of UIP applying the 2011 UIP criteria as well as applying the 2018 UIP update.

Chest CT imaging features for prediction of treatment response in cryptogenic and connective tissue disease-related organizing pneumonia

OBJECTIVES

To investigate CT imaging features associated with poor clinical outcome after corticosteroid treatment in patients diagnosed with cryptogenic organizing pneumonia (COP) and connective tissue disease-related organizing pneumonia (CTD-OP) and to assess the difference in CT findings and treatment responses between COP and CTD-OP.

METHODS

Chest CT images from 166 patients (COP, 131; CTD-OP, 35) with pathologically proven organizing pneumonia were reviewed by two thoracic radiologists. The type, distribution pattern, and extent of parenchymal abnormalities, along with other associated imaging features, were assessed for each patient. Logistic regression analyses were used to identify features associated with poor clinical outcomes such as residual disease (RD) and disease relapse. The differences between COP and CTD-OP were also analyzed.

RESULTS

Consolidation involving more than 10% of parenchyma (hazard ratio [HR], 2.27), detectable bronchiectasis (HR, 3.59), and diagnosis of CTD-OP (HR, 4.31) were associated with a higher risk of RD after adjustments for patient age and sex. More than 10% consolidation involvement (HR, 2.54) and diagnosis of CTD-OP (HR, 6.42) were also associated with a higher risk of disease relapse. Compared with COP, CTD-OP demonstrated a greater extent of parenchymal abnormalities, especially consolidation, and was less likely to show a peribronchovascular distribution pattern.

CONCLUSION

Bronchiectasis and a greater extent of consolidation were associated with RD, with the latter also being associated with disease relapse. Compared with COP, CTD-OP was associated with worse treatment outcomes and demonstrated a greater extent of parenchymal abnormalities, which were also less likely to show a peribronchovascular pattern.

KEY POINTS

• The presence of bronchiectasis and a high parenchymal involvement of consolidation on initial chest CT were associated with a worse response to corticosteroids in patients with organizing pneumonia. • Connective tissue disease-related organizing pneumonia (CTD-OP) was associated with worse treatment outcomes than its idiopathic counterpart cryptogenic organizing pneumonia (COP). • Compared with COP, CTD-OP generally demonstrated a greater extent of parenchymal abnormalities, especially consolidation, and was less likely to show a peribronchovascular distribution pattern.

Pulmonary involvement in human visceral leishmaniasis: Clinical and tomographic evaluation

Visceral leishmaniasis (VL) is a severe, systemic and potentially lethal parasitosis. The lung, like any other organ, can be affected in VL, and interstitial pneumonitis has been described in past decades. This research aimed to bring more recent knowledge about respiratory impairment in VL, characterizing pulmonary involvement through clinical, radiographic and tomographic evaluation. This is an observational, cross-sectional study that underwent clinical evaluation, radiography and high-resolution computed tomography of the chest in patients admitted with the diagnosis of VL in a university service in Northeast Brazil, from January 2015 to July 2018. The sample consisted of 42 patients. Computed tomography was considered abnormal in 59% of patients. Images compatible with pulmonary interstitial involvement were predominant (50%). The most observed respiratory symptom was cough (33.3%), followed by tachypnea (14.1%). Chest radiography was altered in only four patients. VL is a disease characterized by systemic involvement and broad spectrum of clinical manifestations. The respiratory symptoms and tomographic alterations found show that the involvement of respiratory system in VL deserves attention because it is more common than previously thought. Chest X-ray may not reveal this impairment.

Magnetic resonance imaging of interstitial lung diseases: A state-of-the-art review

Magnetic resonance imaging (MRI) has been emerging as an imaging modality to assess interstitial lung diseases (ILD). An optimal chest MRI protocol for ILDs should include non-contrast breath-holding sequences, steady-state free-precession sequences, and contrast-enhanced sequences. One of the main MRI applications in ILDs is the differentiation between areas of active inflammation (i.e. reversible stage) and fibrosis. Alveolitis presents high signal intensity on T2-weighted sequences (WS) and early-enhancement on contrast-enhanced MR sequences, while fibrotic-predominant lesions present low signal and late-enhancement in these sequences, respectively. MRI can be useful in connective tissue diseases, idiopathic pulmonary fibrosis, and sarcoidosis. The aim of this state-of-the-art review was to perform a state-of-the-art review on the use of MRI in ILDs, and propose the optimal MRI protocols for imaging ILDs.

Metabolomics in chronic lung diseases

Chronic lung diseases represent a significant global burden. Their increasing incidence and complexity render a comprehensive, multidisciplinary and personalized approach to each patient, critically important. Most recently, unique biochemical pathways and disease markers have been identified through large-scale metabolomic studies. Metabolomics is the study of metabolic pathways and the measurement of unique biomolecules in a living system. Analysing samples from different compartments such as bronchoalveolar lavage fluid (BALF) and plasma has proven useful for the characterization of a number of pathological conditions and offers promise as a clinical tool. For example, several studies using mass spectrometry (MS) have shown alterations in the sphingolipid metabolism of chronic obstructive pulmonary disease (COPD) sufferers. In this article, we present a practical review of the application of metabolomics to the study of chronic lung diseases (CLD): COPD, idiopathic pulmonary fibrosis (IPF) and asthma. The insights, which the analytical strategies employed in metabolomics, have provided to the dissection of the biochemistry of CLD and future clinical biomarkers are explored.

Lung Infections

A review of pulmonary infections of all types with diagnostic and morphological features.

Validation of a model for predicting smear-positive active pulmonary tuberculosis in patients with initial acid-fast bacilli smear-negative sputum

OBJECTIVES

The objective of this study was to develop a predictive model for final smear-positive (SP) active pulmonary tuberculosis (aPTB) in patients with initial negative acid fast bacilli (AFB) sputum smears (iSN-SP-aPTB) based on high-resolution computed tomography (HRCT).

METHOD AND MATERIALS

Eighty (126, 21) patients of iSN-SP-aPTB and 402 (459, 876) patients of non-initial positive acid fast bacilli (non-iSP) pulmonary disease without iSN-SP-aPTB were included in a derivation (validation, prospective) cohort. HRCT characteristics were analysed, and multivariable regression and receiver operating characteristic (ROC) curve analysis was performed to develop a score predictive of iSN-SP-aPTB.

RESULTS

The derivation cohort showed clusters of nodules/mass of the right upper lobe or left upper lobe were independent predictors of iSN-SP-aPTB, while bronchiectasis in the right middle lobe or left lingual lobe were negatively associated with iSN-SP-aPTB. A predictive score for iSN-SP-aPTB based on these findings was tested in the validation and prospective cohorts. With an ideal cut-off score = 1, the sensitivity, specificity, positive predictive value, and negative predictive value of the prediction model were 87.5% (90%, 90.5%), 99% (97.1%, 98.4%), 94.6% (81.3%, 57.5%), and 97.6% (97%, 99.8%) in the derivation (validation, prospective) cohorts, respectively.

CONCLUSIONS

The model may help identify iSN-SP-aPTB among patients with non-iSP pulmonary diseases.

KEY POINTS

• Smear-positive active pulmonary tuberculosis that is initial smear-negative (iSN-SP-aPTB) is infectious. • High-resolution computed tomography can identify iSN-SP-aPTB among non-iSP pulmonary diseases. • Clusters nodules/mass in right/left upper lobe are positively associated with iSN-SP-aPTB. • Bronchiectasis in right middle/left lingual lobe is negatively associated with iSN-SP-aPTB. • The model may have high post-test probability in identifying iSN-SP-aPTB.

Pulmonary infection caused by Mycobacterium kansasii: findings on computed tomography of the chest

Objective

To describe the main tomography findings in patients diagnosed with pulmonary infection caused by Mycobacterium kansasii.

Materials and Methods

Retrospective study of computed tomography scans of 19 patients with pulmonary infection by M. kansasii.

Results

Of the 19 patients evaluated, 10 (52.6%) were male and 9 (47.4%) were female. The mean age of the patients was 58 years (range, 33-76 years). Computed tomography findings were as follows: architectural distortion, in 17 patients (89.5%); reticular opacities and bronchiectasis, in 16 (84.2%); cavities, in 14 (73.7%); centrilobular nodules, in 13 (68.4%); small consolidations, in 10 (52.6%); atelectasis and large consolidations, in 9 (47.4%); subpleural blebs and emphysema, in 6 (31.6%); and adenopathy, in 1 (5.3%).

Conclusion

There was a predominance of cavities, as well as of involvement of the small and large airways. The airway disease was characterized by bronchiectasis and bronchiolitis presenting as centrilobular nodules.

Cystic and nodular lung disease

Diffuse cystic and nodular lung diseases have characteristic imaging findings. The most common causes of cystic lung disease are lymphangioleiomyomatosis and Langerhans cell histiocytosis. Other less common cystic lung diseases include Birt-Hogg-Dube syndrome, lymphocytic interstitial pneumonitis, and light chain deposition disease. Computed tomography is used to differentiate cystic lung disease from emphysema, honeycombing, cavities, and bronchiectasis, which mimic cystic lung disease. Diffuse nodular lung disease are categorized as centrilobular, perilymphatic, and random types. In diffuse nodular lung disease, a specific diagnosis is achieved through a combination of history, physical examination, and imaging findings.

Emphysema mimicking interstitial lung disease: Two case reports

Honeycombing in general is a sign of severe end-stage fibrosis. Here we present two cases, where the combination of emphysema, acute inflammation and pulmonary embolism gave an appearance of honeycombing seen in pulmonary fibrosis. HRCT interpretation in the evaluation of acutely ill patients with pulmonary infection is a challenge. Our case reports emphasize the importance of a multidisciplinary approach, when it comes to patients with suspected complicated pulmonary diseases. At the same time they give very realistic examples of the challenges found in diagnosing patients with simultaneous acute and chronic pulmonary diseases.

Interpretation of autoantibody positivity in interstitial lung disease and lung-dominant connective tissue disease

The initial evaluation of patients with interstitial lung disease (ILD) primarily involves a comprehensive, active search for the cause. Autoantibody assays, which can suggest the presence of a rheumatic disease, are routinely performed at various referral centers. When interstitial lung involvement is the condition that allows the definitive diagnosis of connective tissue disease and the classical criteria are met, there is little debate. However, there is still debate regarding the significance, relevance, specificity, and pathophysiological role of autoimmunity in patients with predominant pulmonary involvement and only mild symptoms or formes frustes of connective tissue disease. The purpose of this article was to review the current knowledge of autoantibody positivity and to discuss its possible interpretations in patients with ILD and without clear etiologic associations, as well as to enhance the understanding of the natural history of an allegedly new disease and to describe the possible prognostic implications. We also discuss the proposition of a new term to be used in the classification of ILDs: lung-dominant connective tissue disease.

Follicular bronchiolitis in primary ciliary dyskinesia

Ciliary dysfunction in primary ciliary dyskinesia (PCD) may be associated with bronchiolitis. Diffuse bronchiolitis has been reported in a subset of PCD patients who have Kartagener's syndrome in Japan. We report a case of follicular bronchiolitis (FB) in a case of PCD presenting with recurrent episodes of cough, dyspnea, and bronchiectasis. This may motivate researchers to study rarer variants and presentations in PCD.

A high resolution computer tomography scoring system to predict culture-positive pulmonary tuberculosis in the emergency department

This study evaluated the use of high-resolution computed tomography (HRCT) to predict the presence of culture-positive pulmonary tuberculosis (PTB) in adult patients with pulmonary lesions in the emergency department (ED). The study included a derivation phase and validation phase with a total of 8,245 patients with pulmonary disease. There were 132 patients with culture-positive PTB in the derivation phase and 147 patients with culture-positive PTB in the validation phase. Imaging evaluation of pulmonary lesions included morphology and segmental distribution. The post-test probability ratios between both phases in three prevalence areas were analyzed. In the derivation phase, a multivariate analysis model identified cavitation, consolidation, and clusters/nodules in right or left upper lobe (except anterior segment) and consolidation of the superior segment of the right or left lower lobe as independent positive factors for culture-positive PTB, while consolidation of the right or left lower lobe (except superior segment) were independent negative factors. An ideal cutoff point based on the receiver operating characteristic (ROC) curve analysis was obtained at a score of 1. The sensitivity, specificity, positivity predictive value, and negative predictive value from derivation phase were 98.5% (130/132), 99.7% (3997/4008), 92.2% (130/141), and 99.9% (3997/3999). Based on the predicted positive likelihood ratio value of 328.33 in derivation phase, the post-test probability was observed to be 91.5% in the derivation phase, 92.5% in the validation phase, 94.5% in a high TB prevalence area, 91.0% in a moderate prevalence area, and 76.8% in moderate-to-low prevalence area. Our model using HRCT, which is feasible to perform in the ED, can promptly diagnose culture-positive PTB in moderate and moderate-to-low prevalence areas.

Postmortem virtual volumetry of the heart and lung in situ using CT data for investigating terminal cardiopulmonary pathophysiology in forensic autopsy

Postmortem CT (PM-CT) is useful to investigate the viscera in situ before opening the body cavity at autopsy. The present study investigated heart and lung volumes in situ with regard to the cause of death as possible indexes of terminal cardiopulmonary dysfunction by means of PM-CT data analysis of forensic autopsy cases within 3 days postmortem (n=70). Estimated heart volume was larger in sudden cardiac death (SCD; n=10) and fatal methamphetamine abuse (n=5) than in other groups, including mechanical asphyxiation (n=12), drowning (n=11), acute alcohol/sedative-hypnotic intoxication (n=8), fire fatality (n=12), hyperthermia (heatstroke; n=6) and fatal hypothermia (cold exposure; n=6). Estimated combined lung volume was larger in drowning, smaller in fire fatality due to carbon monoxide intoxication and SCD, and intermediate in other groups. Volume ratio of the lung to heart was higher in drowning, lower in SCD, and intermediate or varied in other groups; high and low ratios can indicate predominant/antecedent pulmonary and cardiac dysfunctions, respectively. These findings provide quantitative data that are not available at conventional autopsy or by routine two-dimensional CT morphology to assess three-dimensional gross heart and lung morphologies for interpreting terminal cardiopulmonary pathophysiology, detecting significant difference between SCD and other causes of death, especially mechanical asphyxiation and drowning.

Pulmonary manifestations of Sjögren's syndrome

Sjögren's syndrome (SS) is primarily defined by its impact on the oral and ocular system resulting in xerostomia and xerophthalmia. However, SS can also manifest throughout the respiratory system. Subclinical pulmonary involvement is common. Clinically significant involvement can result in a 4-fold increased risk of death. Thus, recognizing the many potential presentations of SS in the lung is critical in caring for patients with SS. Additionally, SS should be included in the differential diagnosis of a number of forms of interstitial lung disease.

Ground-glass opacity in lung metastasis from breast cancer: a case report

A 43-year-old woman with breast cancer who was on neoadjuvant chemotherapy presented with cough, sputum and mild fever. High-resolution computed tomography showed diffuse ground glass opacities in bilateral lungs and subpleural patchy consolidations. Initially, she was thought to have pneumonia or interstitial lung diseases such as drug-induced pneumonitis and treated with antibiotics and steroids. She subsequently got breast cancer surgery because of disease progression, and concurrent thoracoscopic lung biopsy revealed metastatic carcinoma of the lung from breast cancer. The diagnosis of suspected interstitial lung disease can be made without lung biopsy, but malignancy should always be considered and lung biopsy should be performed in the absence of a definitive clinical diagnosis.

Mimics in chest disease: interstitial opacities

Septal, reticular, nodular, reticulonodular, ground-glass, crazy paving, cystic, ground-glass with reticular, cystic with ground-glass, decreased and mosaic attenuation pattern characterise interstitial lung diseases on high-resolution computed tomography (HRCT). Occasionally different entities mimic each other, either because they share identical HRCT findings or because of superimposition of patterns. Idiopathic pulmonary fibrosis (IPF), fibrosis associated with connective tissue disease, asbestosis, end-stage sarcoidosis or chronic hypersensitivity pneumonitis (HP) may present with lower zone, subpleural reticular pattern associated with honeycombing. Lymphangiomyomatosis may be indistinguishable from histiocytosis or extensive emphysema. Both pulmonary oedema and lymphangitic carcinomatosis may be characterised by septal pattern resulting from thickened interlobular septa. Ill-defined centrilobular nodular pattern may be identically present in HP and respiratory bronchiolitis–associated with interstitial lung disease (RBILD). Sarcoidosis may mimic miliary tuberculosis or haematogenous metastases presenting with miliary pattern, while endobronchial spread of tuberculosis may be indistinguishable from panbronchiolitis, both presenting with tree-in-bud pattern. Atypical infection presenting with ground-glass mimics haemorrhage. Ground-glass pattern with minimal reticulation is seen in desquamative interstitial pneumonia (DIP), RBILD and non-specific interstitial pneumonia (NSIP). Obliterative bronchiolitis and panlobular emphysema may present with decreased attenuation pattern, while obliterative bronchiolitis, chronic pulmonary embolism and HP may manifest with mosaic attenuation pattern. Various mimics in interstitial lung diseases exist. Differential diagnosis is narrowed based on integration of predominant HRCT pattern and clinical history.

Teaching Points

• To learn about the different HRCT patterns, which are related to interstitial lung diseases.

• To be familiar with the more “classical” entities presenting with each HRCT pattern.

• To discuss possible overlap of different HRCT patterns and the more common mimics in each case.

• To learn about some clues that help differentiate the various diagnostic mimics on HRCT.

My approach to interstitial lung disease using clinical, radiological and histopathological patterns

The complex world of interstitial lung disease presents nearly insurmountable challenges to the general surgical pathologist faced with a lung biopsy in this setting. The pathology is often inflammatory and always requires clinical and radiological context for a relevant and clinically useful histopathological diagnosis. A pattern-based histopathological approach to interstitial lung disease provides a “map” for the general pathologist to navigate this area successfully, especially so when used with aid of the clinical and radiological patterns of presentation.