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.

Objective: To estimate the prevalence of latent Mycobacterium tuberculosis infection (LTBI) in renal transplant recipients and to assess sociodemographic, behavioral, and clinical associations with positive tuberculin skin test (TST) results. Methods: This was a cross-sectional study of patients aged ≥ 18 years who underwent renal transplantation at the Renal Transplant Center of the Federal University of Minas Gerais Hospital das Clínicas, located in the city of Belo Horizonte, Brazil. We included renal transplant recipients who underwent the TST between January 2011 and July 2013. If the result of the first TST was negative, a second TST was administered. Bivariate and multivariate analyses using logistic regression were used to determine factors associated with positive TST results. Results: The sample included 216 patients. The prevalence of LTBI was 18.5%. In the multivariate analysis, history of contact with a tuberculosis case and preserved graft function (estimated glomerular filtration rate ≥ 60 mL/min/1.73 m2) were associated with positive TST results. TST induration increased by 5.8% from the first to the second test, which was considered significant (p = 0.012). Conclusions: The prevalence of LTBI was low in this sample of renal transplant recipients. The TST should be administered if renal graft function is preserved. A second TST should be administered if the first TST is negative.

Keywords: Tuberculosis; Tuberculin test; Immunocompromised host.

Objective: To present the high-resolution computed tomography (HRCT) findings of pulmonary alveolar microlithiasis. Methods: The HRCT scans of 10 adult patients (seven females and three males; mean age, 38.7 years) were retrospectively analyzed. The films were studied independently by two radiologists. Results: The most common tomographic findings were ground-glass attenuation and linear subpleural calcifications, which were seen in 90% of the patients. Other relevant findings were small parenchymal nodules, calcification along the interlobular septa, nodular cissures, subpleural nodules, subpleural cysts, dense consolidations, and a mosaic pattern of attenuation. Conclusions: The HRCT findings presented by individuals with pulmonary alveolar microlithiasis are distinct. In most cases, such findings can form the basis of the diagnosis, eliminating the need to perform a lung biopsy.

Keywords: Tomography, X-Ray Computed; Lithiasis/lung; Lung diseases.

Due to the increasing number and improved survival of lung transplant recipients, radiologists should be aware of the imaging features of the postoperative complications that can occur in such patients. The early treatment of complications is important for the long-term survival of lung transplant recipients. Frequently, HRCT plays a central role in the investigation of such complications. Early recognition of the signs of complications allows treatment to be initiated earlier, which improves survival. The aim of this pictorial review was to demonstrate the CT scan appearance of pulmonary complications such as reperfusion edema, acute rejection, infection, pulmonary thromboembolism, chronic rejection, bronchiolitis obliterans syndrome, cryptogenic organizing pneumonia, post-transplant lymphoproliferative disorder, bronchial dehiscence and bronchial stenosis.

Keywords: Tomography, X-ray computed; Lung transplantation; Postoperative complications.

Sarcoidosis is a systemic disease of unknown etiology, characterized by noncaseating granulomas. Although it may affect any organ, morbidity and mortality are most commonly related to pulmonary involvement, which is found in 80-90% of patients. This study illustrates the principal manifestations of sarcoidosis seen in high-resolution computed tomography scans, including typical as well as atypical forms.

Keywords: Sarcoidosis. Lung. High-resolution computed tomography.

Objective: To present findings on computed tomography scans of the chest indicative of extramedullary hematopoiesis in six patients. Methods: We retrospectively analyzed computed tomography scans of six adult patients-five males and one female-with a mean age of 36.5 years. Two radiologists independently reviewed the scans, and a consensus was reached in discrepant cases. Results: The most common finding in the scans was lower paravertebral masses with heterogeneous content (four patients). The scans of two patients showed a solitary parietal and pleural mass. Conclusions: There are findings in computed tomography scans that are highly suggestive of extramedullary hematopoiesis, especially when those findings correlate with underlying blood diseases. Such findings, in most of the cases, allow physicians to dispense with histopathological confirmation.

Keywords: Tomography, X-ray computed; Hematopoiesis, extramedullary; Mediastinum/physiopathology; Anemia, sickle cell.

The objective of this systematic review was to select articles including chest X-ray or chest CT findings in patients who developed pulmonary tuberculosis following solid organ transplantation (lung, kidney, or liver). The following search terms were used: "tuberculosis"; "transplants"; "transplantation"; "mycobacterium"; and "lung". The databases used in this review were PubMed and the Brazilian Biblioteca Virtual em Saúde (Virtual Health Library). We selected articles in English, Portuguese, or Spanish, regardless of the year of publication, that met the selection criteria in their title, abstract, or body of text. Articles with no data on chest CT or chest X-ray findings were excluded, as were those not related to solid organ transplantation or pulmonary tuberculosis. We selected 29 articles involving a collective total of 219 patients. The largest samples were in studies conducted in Brazil and South Korea (78 and 35 patients, respectively). The imaging findings were subdivided into five common patterns. The imaging findings varied depending on the transplanted organ in these patients. In liver and lung transplant recipients, the most common pattern was the classic one for pulmonary tuberculosis (cavitation and "tree-in-bud" nodules), which is similar to the findings for pulmonary tuberculosis in the general population. The proportion of cases showing a miliary pattern and lymph node enlargement, which is most similar to the pattern seen in patients coinfected with tuberculosis and HIV, was highest among the kidney transplant recipients. Further studies evaluating clinical data, such as immunosuppression regimens, are needed in order to improve understanding of the distribution of these imaging patterns in this population.

Keywords: Tomography, X-ray computed; Radiography; Tuberculosis, pulmonary; Lung/transplantation; Kidney/transplantation; Liver/transplantation.

The aim of this pictorial essay was to present the main computed tomography findings seen in diffuse diseases of the trachea. The diseases studied included amyloidosis, tracheobronchopathia osteochondroplastica, tracheobronchomegaly, laryngotracheobronchial papillomatosis, lymphoma, neurofibromatosis, relapsing polychondritis, Wegener's granulomatosis, tuberculosis, paracoccidioidomycosis, and tracheobronchomalacia. The most common computed tomography finding was thickening of the walls of the trachea, with or without nodules, parietal calcifications, or involvement of the posterior wall. Although computed tomography allows the detection and characterization of diseases of the central airways, and the correlation with clinical data reduces the diagnostic possibilities, bronchoscopy with biopsy remains the most useful procedure for the diagnosis of diffuse lesions of the trachea.

Keywords: Thoracic diseases; Tracheal diseases; Tomography, X-ray computed; Trachea.

Abstract Objective: To present the findings of computed tomography (CT) scans of the chest in patients with laryngotracheobronchial papillomatosis. Methods: We retrospectively analyzed CT scans of eight patients, five males and three females, ranging from 5 to 18 years of age with a mean age of 10.5 years. Images were independently reviewed by two radiologists. In discrepant cases, a consensus was reached. Results: The most common CT findings were intratracheal polypoid lesions and pulmonary nodules, many of which were cavitated. Conclusions: In patients with laryngotracheobronchial papillomatosis, the most common tomographic finding was the combination of intratracheal polypoid lesions and multiple pulmonary nodules, many of which were cavitated.

Keywords: Tomography, X-ray computed; Papilloma; Tracheal neoplasms.

Objective: To evaluate the radiological characteristics of conglomerate masses using high-resolution computed tomography of the chest. Methods: From among the patients treated between 1986 and 2004 at the Antonio Pedro University Hospital, 75 patients with silicosis and massive fibrosis, most working in the field of sandblasting, were selected for study. These patients were submitted to a clinical evaluation, chest X-ray and high-resolution computed tomography of the chest. Results: In more than half of the patients with accelerated silicosis, the chest X-ray revealed large type B and C opacities, denoting the severity of the disease in those patients. In 1 case, a unilateral mass simulating lung cancer was observed. High-resolution computed tomography scans of the chest were acquired for 44 patients. In most cases (88.6%), the masses were located in the superior and posterior thirds of the lung. Common findings within the masses included air bronchograms (in 70.4%) and calcifications (in 63.6%). A history of tuberculosis was reported by 52% of the patients. Conclusion: In the vast majority of cases, the masses were bilateral, predominantly located in the superior and posterior regions of the lung, featuring air bronchograms and interposed calcifications. Concomitant calcification of the mediastinal and hilar lymph nodes was another common finding. Exposure to high concentrations of dust and having a history of tuberculosis were considered significant risk factors for the development of progressive massive fibrosis.

Keywords: Pulmonary fibrosis; Silicosis; Silicon dioxide; Occupational diseases; Environmental exposure;

Objective: To evaluate the etiology of and factors associated with pulmonary infection in kidney and kidney-pancreas transplant recipients. Methods: This was a single-center case-control study conducted between December of 2017 and March of 2020 at a referral center for kidney transplantation in the city of Belo Horizonte, Brazil. The case:control ratio was 1:1.8. Cases included kidney or kidney-pancreas transplant recipients hospitalized with pulmonary infection. Controls included kidney or kidney-pancreas transplant recipients without pulmonary infection and matched to cases for sex, age group, and donor type (living or deceased). Results: A total of 197 patients were included in the study. Of those, 70 were cases and 127 were controls. The mean age was 55 years (for cases) and 53 years (for controls), with a predominance of males. Corticosteroid use, bronchiectasis, and being overweight were associated with pulmonary infection risk in the multivariate logistic regression model. The most common etiologic agent of infection was cytomegalovirus (in 14.3% of the cases), followed by Mycobacterium tuberculosis (in 10%), Histoplasma capsulatum (in 7.1%), and Pseudomonas aeruginosa (in 7.1%). Conclusions: Corticosteroid use, bronchiectasis, and being overweight appear to be risk factors for pulmonary infection in kidney/kidney-pancreas transplant recipients, endemic mycoses being prevalent in this population. Appropriate planning and follow-up play an important role in identifying kidney and kidney-pancreas transplant recipients at risk of pulmonary infection.

Keywords: Kidney transplantation; Immunosuppression therapy; Pneumonia.

Objective: To evaluate the main aspects on CT scans of six patients hospitalized in a bone marrow transplant ward, diagnosed with invasive pulmonary aspergillosis (IPA), during an in-hospital outbreak of the disease. Methods: We reviewed 10 chest CT scans of six neutropenic or immunocompromised patients hospitalized in the hematology and bone marrow transplant ward of the Hospital São Paulo, in the city of São Paulo, Brazil, who were diagnosed with IPA between April of 2007 and October of 2007. The diagnosis of IPA was confirmed by anatomopathological findings (in 2 cases), culture (in 3 cases) or appropriate treatment response (in 1 case). Results: We evaluated the CT scans of three male and three female patients, ranging from 22 to 58 years of age. The most common tomographic findings were nodules (5/6 cases) and areas of consolidation (2/6 cases). The nodules were more often multiple (3/5 cases), with irregular contours (4/5 cases) and accompanied by the halo sign (3/5 cases). One case presented multiple, centrally distributed areas of consolidation, and another presented an isolated, peripheral area of consolidation. Areas of ground-glass attenuation and septal thickening were found in three and two patients, respectively. Bilateral pleural effusion occurred in three cases. Conclusions: Consolidation, nodules, septal thickening, pleural effusion and ground-glass opacities were the principal tomographic findings in the six patients hospitalized in the abovementioned ward during the IPA outbreak. The nodules were often (in 67% of the cases) accompanied by the halo sign, a classically described finding in patients with IPA.

Keywords: Aspergillosis; Lung diseases, fungal; Neutropenia; Bone marrow transplantation; Tomography, X-Ray computed.

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.

Objectives: To evaluate the performance of a computer program designed to facilitate the detection of pulmonary nodules using multidetector computed tomography (MDCT) scans of the chest. Methods: We evaluated 24 consecutive MDCT scans of the chest at the Fleury Diagnostic Imaging Center during the period from October 7 to October 19 of 2006, using a 64-channel CT scanner. The study comprised 12 females and 12 males, ranging from 35 to 77 years of age (mean, 57.9 years). Double reading and a computer-aided diagnosis (CAD) system were used in order to perform two independent analyses of the data. The nodules found using both methods were recorded, and the data were compared. Results: The total sensitivity of CAD for the detection of nodules was 16.5%, increasing to 55% when nodules <4 mm in diameter were excluded. Sensitivity by diameter was 6.5% for nodules <4 mm, 45% for nodules of 4-6 mm, 100% for nodules of 6 mm-1 cm, and 0% for nodules >1 cm. More than 99% of true nodules detected by CAD were registered in the image double-reading process. Conclusions: In this preliminary 24-case study, the sensitivity of computer program tested was not significantly greater than that of the double-reading process that is routinely performed in this facility.

Keywords: Image interpretation, computer-assisted; Coin lesion, pulmonary; Tomography, X-ray computed.

Emphysema is a condition of the lung, characterized by the abnormal increase in the size of the airspace distal to the terminal bronchioles. Currently, emphysema is the fourth leading cause of death in the USA, affecting 14 million people. The present article describes the principal tools in the imaging diagnosis of emphysema, from the early days until the present. We describe traditional techniques, such as chest X-ray, together with the evolution of computed tomography (CT) to more advanced forms, such as high resolution CT, as well as three-dimensional CT densitometry and volumetric assessment.

Keywords: Emphysema; Radiology; Tomography, X-Ray computed; Radiography, thoracic.

The authors report the case of a female patient who developed chronic eosinophilic pneumonia secondary to long-term use of nitrofurantoin for prophylaxis of recurrent urinary tract infections due to urethral stenosis. On high-resolution computed tomography scans, the pulmonary reaction to nitrofurantoin most commonly manifests as an interstitial-alveolar pattern in both lung bases. However, in this case, the alterations were most pronounced in the periphery of the upper lobes. In itself, this tomographic profile is strongly indicative of chronic eosinophilic pneumonia. The patient had previously been submitted to an open lung biopsy. The diagnosis of chronic eosinophilic pneumonia was confirmed through a review of the biopsy.

Keywords: Pneumonia; Pulmonary eosinophilia; Nitrofurantoin/adverse effects; Tomography, X-ray computed.

Objective: This study aimed to use high-resolution computed tomography scans of the chest to characterize the principal alterations occurring in cases of hydrostatic pulmonary edema. Methods: A retrospective analysis was made of the tomography scans of 15 patients presenting clinical profiles of hydrostatic pulmonary edema. The cases were divided into five groups by etiology: congestive heart failure (n = 7); acute mitral valve disease (n = 2); acute myocardial infarction (n = 2); myocarditis (n = 2); and fibrosing mediastinitis (n = 2). Results: The principal findings in the cases of hydrostatic pulmonary edema were ground-glass opacities (in 100%), interlobular septal thickening (in 100%), pleural effusion (in 87%) and peribronchovascular interstitial thickening (in 80%). Other, less common, findings were increased blood vessel diameter, consolidations and air-space nodules. Conclusion: The predominant pattern found in the patients studied was that of ground-glass opacities accompanied by interlobular septal thickening (mosaic attenuation pattern) and bilateral (predominantly right-sided) pleural effusion.

Keywords: Pulmonary edema; Tomography, X-ray computed; Lung diseases

Objective: To determine the incidence of the reversed halo sign (RHS) in patients with pulmonary infarction (PI) due to acute pulmonary embolism (PE), detected by computed tomography angiography (CTA) of the pulmonary arteries, and to describe the main morphological features of the RHS. Methods: We evaluated 993 CTA scans, stratified by the risk of PE, performed between January of 2010 and December of 2014. Although PE was detected in 164 scans (16.5%), three of those scans were excluded because of respiratory motion artifacts. Of the remaining 161 scans, 75 (46.6%) showed lesions consistent with PI, totaling 86 lesions. Among those lesions, the RHS was seen in 33 (38.4%, in 29 patients). Results: Among the 29 patients with scans showing lesions characteristic of PI with the RHS, 25 (86.2%) had a single lesion and 4 (13.8%) had two, totaling 33 lesions. In all cases, the RHS was in a subpleural location. To standardize the analysis, all images were interpreted in the axial plane. Among those 33 lesions, the RHS was in the right lower lobe in 17 (51.5%), in the left lower lobe in 10 (30.3%), in the lingula in 5 (15.2%), and in the right upper lobe in 1 (3.0%). Among those same 33 lesions, areas of low attenuation were seen in 29 (87.9%). The RHS was oval in 24 (72.7%) of the cases and round in 9 (27.3%). Pleural effusion was seen in 21 (72.4%) of the 29 patients with PI and the RHS. Conclusions: A diagnosis of PE should be considered when there are findings such as those described here, even in patients with nonspecific clinical symptoms.

Keywords: Pulmonary embolism; Pulmonary infarction; Computed tomography angiography.