Objective: To correlate the prevalence and prognosis of each HRCT pattern of typical, probable, and indeterminate usual interstitial pneumonia (UIP) with the clinical multidisciplinary diagnosis of interstitial lung disease (ILD). Methods: We included all patients with a multidisciplinary diagnosis of ILD with an HRCT pattern of typical UIP, probable UIP, or indeterminate for UIP. Clinical and histopathological data, pulmonary function tests, and survival status were retrospectively obtained. The final diagnosis was validated by a multidisciplinary team. Results: A total of 244 patients were included in the study, with a mean age of 68 ±13 years and being 52.5% males. In a total of 106 patients with typical UIP pattern, 62% had the multidisciplinary diagnosis of IPF, 20% had chronic hypersensitivity pneumonitis (CHP), and 10% had connective tissue disease-related ILD (CTD-ILD). Out of the 114 cases with probable UIP, CTD-ILD corresponded to 39%, IPF to 31%, desquamative interstitial pneumonia to 11%, drug-related lung disease to 9%, and CHP to 8%. In the 24 patients with CT indeterminate for UIP, CTD-ILD was the final diagnosis in 33%, followed by desquamative interstitial pneumonia (21%), and IPF (13%). Patients with typical UIP were more likely to die or had lung transplantation in the follow-up (17.9% and 11.3%, respectively). Conclusion: IPF, CHP, and CTD-ILD were the main differential diagnoses in patients with HRCT patterns of typical, probable and indeterminate UIP. Patients with HRCT typical UIP pattern were more likely to die or had lung transplantation in the follow-up.

Keywords: High resolution computed tomography; Interstitial lung disease; Idiopathic pulmonary fibrosis; Usual interstitial pneumonia.

High-resolution computed tomography (HRCT) is the radiological imaging technique best suited to revealing changes in lung structure. Various HRCT findings, taken together, can represent typical patterns. These patterns, in conjunction with the anatomical distribution of findings and with clinical data, can narrow the differential diagnosis of diffuse interstitial lung disease and, in many cases, indicate the correct diagnosis with a high degree of accuracy. The most common HRCT patterns seen in cases of diffuse interstitial lung diseases are the nodular pattern, linear/reticular opacities, cystic lesions, ground-glass opacities and consolidations. This article reviews the correlations between HRCT patterns and pathologic findings, summarizing the most common causes, as well as detailing the methods of investigation employed in order to diagnose the most common types of chronic diffuse lung disease.

Keywords: Lung diseases, interstitial/pathology; Tomography, X-Ray computed; Diagnostic techniques, respiratory system.

Objective: Respiratory infections constitute a major cause of morbidity and mortality in solid organ transplant recipients. The incidence of pulmonary tuberculosis is high among such patients. On imaging, tuberculosis has various presentations. Greater understanding of those presentations could reduce the impact of the disease by facilitating early diagnosis. Therefore, we attempted to describe the HRCT patterns of pulmonary tuberculosis in lung transplant recipients. Methods: From two hospitals in southern Brazil, we collected the following data on lung transplant recipients who developed pulmonary tuberculosis: gender; age; symptoms; the lung disease that led to transplantation; HRCT pattern; distribution of findings; time from transplantation to pulmonary tuberculosis; and mortality rate. The HRCT findings were classified as miliary nodules; cavitation and centrilobular nodules with a tree-in-bud pattern; ground-glass attenuation with consolidation; mediastinal lymph node enlargement; or pleural effusion. Results: We evaluated 402 lung transplant recipients, 19 of whom developed pulmonary tuberculosis after transplantation. Among those 19 patients, the most common HRCT patterns were ground-glass attenuation with consolidation (in 42%); cavitation and centrilobular nodules with a tree-in-bud pattern (in 31.5%); and mediastinal lymph node enlargement (in 15.7%). Among the patients with cavitation and centrilobular nodules with a tree-in-bud pattern, the distribution was within the upper lobes in 66.6%. No pleural effusion was observed. Despite treatment, one-year mortality was 47.3%. Conclusions: The predominant HRCT pattern was ground-glass attenuation with consolidation, followed by cavitation and centrilobular nodules with a tree-in-bud pattern. These findings are similar to those reported for immunocompetent patients with pulmonary tuberculosis and considerably different from those reported for AIDS patients with the same disease.

Keywords: Lung transplantation; Diagnostic imaging; Mycobacterium infections; Thoracic diseases; Tomography, X-Ray computed/methods; Tuberculosis, pulmonary.

Background: The aim of this study was to describe the signs of active tuberculosis in patients submitted to high resolution computerized tomography and the distribution of lesions along the pulmonary parenchyma. Material and methods: The high resolution CTs performed on 42 patients with tuberculosis either bacteriologically diagnosed or clinical suspected and later confirmed by bacteriological tests were studied. Results: The signs of disease activity observed were airspace nodule (83%), centrilobular nodule (74%), tree-in-bud pattern (67%), cavitations (67%), bronchial thickening (55%), parenchymal consolidations (48%), ground glass opacity (21%) and thickening of the inter and intralobular septa (9%). Conclusion: High resolution computed tomography can be strongly suggestive of disease activity, is particularly helpful in patients with negative smear and/or undetermined radiographs, and allows the establishment of proper treatment, even before mycobacteria are identified in means of culture.

Keywords: Pulmonary tuberculosis. X-ray computed tomography.

Introduction: At present, chest radiography (CR) is the main instrument used in the diagnosis of silicosis, following the International Labor Organization (ILO) recommendations. In incipient cases, the interpretation of radiographs is difficult and disagreement may occur, even among experienced readers. Recently, the possibility of evaluating incipient cases by using high resolution computed tomography (HRCT) has been considered. Objective: To compare CR with HRCT results. Patients and methods: An original group of 135 ex-miners were evaluated by CR, according to ILO recommendations, examined by three readers, from November 1997 to December 1999. HRCT was indicated to 68 patients whose median profusion readings was 1/0 or below. HRCT results were examined by two readers and, in cases of disagreement, a third reader was consulted. HRCT results were classified according to micronodule profusion into categories 0 to 3. CR and HRCT results were compared using McNemar test, weighed Kappa coefficient and log-linear models. Results and conclusion: There was good agreement among the methods in category 0, so it was concluded that both methods are similar in excluding the diagnosis of silicosis. However, in category 1 or greater (diagnosis of the disease) a good agreement among the methods was not observed.

Keywords: Silicosis. Thoracic radiography. Tomography X-ray computed. Pneumoconiosis.

Objective: To evaluate clinical, functional, and CT characteristics, as well as disease progression, in patients with idiopathic inflammatory myopathy-associated interstitial lung disease (IIM-ILD) treated at a referral center in Brazil. Methods: This was a retrospective cohort study analyzing demographic characteristics, clinical variables, pulmonary function test results, HRCT findings, serological profiles, treatments, and outcomes. Results: Seventy-nine IIM-ILD patients were included in the present study. The mean follow-up period was 8.7 ± 4.7 years. The most common diagnosis was antisynthetase syndrome, observed in 51 (64.5%) of the 79 patients. The most common symptoms were dyspnea (in 94.9%), arthralgia (in 82.2%), and muscle weakness (in 75.9%). Mean baseline FVC was 2.19 ± 0.75 L, corresponding to 62.5% of the predicted value. During follow-up, FVC showed significant improvement. The most common CT patterns were indeterminate (in 44.4%) and nonspecific interstitial pneumonia (in 35.4%). Treatment most frequently included prednisone (in 98.7%), azathioprine (in 92.3%), or methotrexate (in 57.7%). Overall survival was 84.8%. Mortality was higher among patients who developed pulmonary hypertension and those who required intravenous methylprednisolone pulse therapy. Conclusions: Most patients with IIM-ILD progress well with immunosuppressive therapy. Pulmonary hypertension and the need for methylprednisolone pulse therapy appear to be associated with higher mortality.

Keywords: Lung diseases, interstitial; Myositis; Antisynthetase syndrome; Tomography; Spirometry.

Objective: To describe the characteristics of a cohort of patients with lung-dominant connective tissue disease (LD-CTD). Methods: This was a retrospective study of patients with interstitial lung disease (ILD), positive antinuclear antibody (ANA) results (≥ 1/320), with or without specific autoantibodies, and at least one clinical feature suggestive of connective tissue disease (CTD). Results: Of the 1,998 patients screened, 52 initially met the criteria for a diagnosis of LD-CTD: 37% were male; the mean age at diagnosis was 56 years; and the median follow-up period was 48 months. During follow-up, 8 patients met the criteria for a definitive diagnosis of a CTD. The remaining 44 patients comprised the LD-CTD group, in which the most prevalent extrathoracic features were arthralgia, gastroesophageal reflux disease, and Raynaud's phenomenon. The most prevalent autoantibodies in this group were ANA (89%) and anti-SSA (anti-Ro, 27%). The mean baseline and final FVC was 69.5% and 74.0% of the predicted values, respectively (p > 0.05). Nonspecific interstitial pneumonia and usual interstitial pneumonia patterns were found in 45% and 9% of HRCT scans, respectively; 36% of the scans were unclassifiable. A similar prevalence was noted in histological samples. Diffuse esophageal dilatation was identified in 52% of HRCT scans. Nailfold capillaroscopy was performed in 22 patients; 17 showed a scleroderma pattern. Conclusions: In our LD-CTD group, there was predominance of females and the patients showed mild spirometric abnormalities at diagnosis, with differing underlying ILD patterns that were mostly unclassifiable on HRCT and by histology. We found functional stability on follow-up. Esophageal dilatation on HRCT and scleroderma pattern on nailfold capillaroscopy were frequent findings and might come to serve as diagnostic criteria.

Keywords: Idiopathic interstitial pneumonias; Autoantibodies; Connective tissue diseases; Autoimmunity.

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 or benign symptoms 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.

Keywords: Idiopathic interstitial pneumonias; Autoantibodies; Connective tissue diseases; Autoimmune diseases; Diagnosis, differential.

Objective: To determine the prevalence of ventilator-associated pneumonia in an intensive care unit, as well as to identify related factors and characterize patient evolution. Methods: This study evaluated 278 patients on mechanical ventilation for more than 24 hours in a university hospital. Results: Ventilator-associated pneumonia developed in 38.1% of the patients, translating to 35.7 cases/1000 ventilator-days: 45.3% were caused by gram-negative agents (Pseudomonas aeruginosa accounting for 22%); and multidrug resistant organisms were identified in 43.4%. In the ventilator-associated pneumonia group, time on mechanical ventilation, time to mechanical ventilation weaning, hospital stays and intensive care unit stays were all longer (p < 0.001). In addition, atelectasis, acute respiratory distress syndrome, pneumothorax, sinusitis, tracheobronchitis and infection with multidrug resistant organisms were more common in the ventilator-associated pneumonia group (p < 0.05). Mortality rates in the intensive care unit were comparable to those observed in the hospital infirmary. Associations between ventilator-associated pneumonia and various factors are expressed as odds ratios and 95% confidence intervals: acute sinusitis (38.8; 3.4-441); > 10 days on mechanical ventilation (7.7; 4.1-14.2); immunosuppression (4.3; 1.3-14.3); acute respiratory distress syndrome (3.5; 1.4-9.0); atelectasis (3.0; 1.2-7.3); cardiac arrest (0.18; 0.05-0.66); and upper gastrointestinal tract bleeding (0.07; 0.009-0.62). The variables found to be associated with in-hospital death were as follows: chronic renal failure (26.1; 1.9-350.7); previous intensive care unit admission (15.6; 1.6-152.0); simplified acute physiologic score II > 50 (11.9; 3.4-42.0); and age > 55 years (4.4; 1.6-12.3). Conclusion: Ventilator-associated pneumonia increased the time on mechanical ventilation and the number of complications, as well as the length of intensive care unit and hospital stays, but did not affect mortality rates.

Keywords: Bacterial pneumonia; Hospital infection; Intensive care units; Prognosis; Prospective studies; Intensive care medicine

Objective: To characterize the prevalence of latent tuberculosis infection (LTBI) in patients with interstitial lung diseases (ILDs) requiring immunosuppression. Only 5 to 10% of individuals infected with Mycobacterium tuberculosis develop tuberculosis, and certain groups of patients have an increased risk of illness, such as the immunocompromised. Patients with ILDs are frequently treated with immunosuppressants and, therefore, might have a higher risk of developing the disease. Methods: Prospective study conducted at the ILD reference center of the Federal University of Paraná from January 2019 to December 2020. The screening of LTBI was performed with the use of the tuberculin skin test (TST). Results: The sample consisted of 88 patients, of whom 64.8% were women, with a mean age of 61.4 years. The most frequent diagnoses were autoimmune rheumatic disease ILD (38.6%) and hypersensitivity pneumonitis (35.2%). The most common immunosuppressant in use at the time of the TST was prednisone, either in combination with mycophenolate (19.3%) or alone (17.1%). The majority of participants had fibrotic lung disease, characterized by a reticular interstitial pattern on chest computed tomography (79.5%) and moderate to severe functional impairment (mean FVC 69.2%). A prevalence of LTBI of 9.1% (CI 95%, 2.1%-15.1%) was found, with a TST median of 13. Conclusion: Patients with ILD who are treated with immunosuppressants are not commonly screened for LTBI, despite being under a greater risk of progression to active disease. This study suggests the need for a more cautious approach to these patients.

Keywords: Latent tuberculosis infection; Interstitial lung diseases; Immunosuppression; Tuberculin test.

Objective: To investigate the correlation of HRCT findings with pulmonary metabolic activity in the corresponding regions using 18F-FDG PET/CT and inflammatory markers in patients with systemic sclerosis (SSc)-associated interstitial lung disease (ILD). Methods: This was a cross-sectional study involving 23 adult patients with SSc-associated ILD without other connective tissue diseases. The study also involved 18F-FDG PET/CT, HRCT, determination of serum chemokine levels, clinical data, and pulmonary function testing. Results: In this cohort of patients with long-term disease (disease duration, 11.8 ± 8.7 years), a nonspecific interstitial pneumonia pattern was found in 19 (82.6%). Honeycombing areas had higher median standardized uptake values (1.95; p = 0.85). Serum levels of soluble tumor necrosis factor receptor 1, soluble tumor necrosis factor receptor 2, C-C motif chemokine ligand 2 (CCL2), and C-X-C motif chemokine ligand 10 were higher in SSc patients than in controls. Serum levels of CCL2-a marker of fibroblast activity-were correlated with pure ground-glass opacity (GGO) areas on HRCT scans (p = 0.007). 18F-FDG PET/CT showed significant metabolic activity for all HRCT patterns. The correlation between serum CCL2 levels and GGO on HRCT scans suggests a central role of fibroblasts in these areas, adding new information towards the understanding of the mechanisms surrounding cellular and molecular elements and their expression on HRCT scans in patients with SSc-associated ILD. Conclusions: 18F-FDG PET/CT appears to be unable to differentiate the intensity of metabolic activity across HRCT patterns in chronic SSc patients. The association between CCL2 and GGO might be related to fibroblast activity in these areas; however, upregulated CCL2 expression in the lung tissue of SSc patients should be investigated in order to gain a better understanding of this association.

Keywords: Tomography; Lung diseases, interstitial; Scleroderma, systemic; Cytokines.

Objective: To investigate the applicability of ultrasound imaging of the diaphragm in interstitial lung disease (ILD). Methods: Using ultrasound, we compared ILD patients and healthy volunteers (controls) in terms of diaphragmatic mobility during quiet and deep breathing; diaphragm thickness at functional residual capacity (FRC) and at total lung capacity (TLC); and the thickening fraction (TF, proportional diaphragm thickening from FRC to TLC). We also evaluated correlations between diaphragmatic dysfunction and lung function variables. Results: Between the ILD patients (n = 40) and the controls (n = 16), mean diaphragmatic mobility was comparable during quiet breathing, although it was significantly lower in the patients during deep breathing (4.5 ± 1.7 cm vs. 7.6 ± 1.4 cm; p < 0.01). The patients showed greater diaphragm thickness at FRC (p = 0.05), although, due to lower diaphragm thickness at TLC, they also showed a lower TF (p < 0.01). The FVC as a percentage of the predicted value (FVC%) correlated with diaphragmatic mobility (r = 0.73; p < 0.01), and an FVC% cut-off value of < 60% presented high sensitivity (92%) and specificity (81%) for indentifying decreased diaphragmatic mobility. Conclusions: Using ultrasound, we were able to show that diaphragmatic mobility and the TF were lower in ILD patients than in healthy controls, despite the greater diaphragm thickness at FRC in the former. Diaphragmatic mobility correlated with ILD functional severity, and an FVC% cut-off value of < 60% was found to be highly accurate for indentifying diaphragmatic dysfunction on ultrasound.

Keywords: Diaphragm/ultrasonography; Lung diseases, interstitial; Respiratory muscles; Respiratory function tests.

Objective: To correlate tomographic findings with pulmonary function findings, as well as to compare chest X-ray findings with high-resolution computed tomography (HRCT) findings, in patients with silicosis. Methods: A cross-sectional study was conducted in 44 non-smoking patients without a history of tuberculosis. Chest X-ray findings were classified according to the International Labour Organization recommendations. Using a semiquantitative system, the following HRCT findings were measured: the full extent of pulmonary involvement; parenchymal opacities; and emphysema. Spirometry and forced oscillation were performed. Pulmonary volumes were evaluated using the helium dilution method, and diffusing capacity of the lung for carbon monoxide was assessed. Results: Of the 44 patients studied, 41 were male. The mean age was 48.4 years. There were 4 patients who were classified as category 0 based on X-ray findings and as category 1 based on HRCT findings. Using HRCT scans, we identified progressive massive fibrosis in 33 patients, compared with only 23 patients when X-rays were used. Opacity score was found to correlate most closely with airflow, DLCO and compliance. Emphysema score correlated inversely with volume, DLCO and airflow. In this sample of patients presenting a predominance of large opacities (75% of the individuals), the deterioration of pulmonary function was associated with the extent of structural changes. Conclusions: In the early detection of silicosis and the identification of progressive massive fibrosis, HRCT scans are superior to X-rays.

Keywords: Silicosis; Occupational diseases; Tomography, x-ray computed; Respiratory function tests.