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 present the computed tomography aspects of Rhodococcus equi pneumonia in seven patients with acquired immunodeficiency syndrome. Methods: A retrospective study of the computed tomography scans of seven patients with acquired immunodeficiency syndrome and Rhodococcus equi infection. Results: The most common findings were consolidation (n = 7), consolidation with cavitation (n = 6), ground glass opacities (n = 6), peribronchial nodules (n = 4) and centrilobular nodules presenting a "tree-in-bud" pattern (n = 3). Conclusion: The most common finding in patients with Rhodococcus equi pulmonary infection and acquired immunodeficiency syndrome was consolidation with cavitation.

Keywords: Acquired immunodeficiency syndrome; Rhodococcus equi; Actimomycetales infections; Lung diseases, fungal; Tomography, emission-computed

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 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.

Reexpansion pulmonary edema (RPE) is a rare, but frequently lethal, clinical entity. The precise pathophysiologic abnormalities associated with this disorder are still unknown: decreased surfactant levels and a pro-inflammatory status are putative mechanisms. Early diagnosis is crucial, since prognosis depends on early recognition and prompt treatment. Considering the high mortality rates related to RPE, preventive measures are still the best available strategy for patient handling. This review provides a brief overview of the pathophysiology, diagnosis, treatment, and prevention of RPE, with practical recommendations for adequate intervention.

Although pneumonectomy is a technically simple procedure, it has been associated with a high (60%) incidence of complications. Respiratory complications account for approximately 15% of such complications. Worldwide, the mortality rate among patients subjected to pneumonectomy is 8.6%. However, the rate among patients developing respiratory complications is 30%. Although postpneumonectomy pulmonary edema is rare (occurring in 3% to 5% of cases), it is a serious complication and is almost always fatal. It was first described twenty years ago and, despite these alarming statistics, little is known regarding the physiopathology of postpneumonectomy pulmonary edema. Once it has become entrenched, the condition is difficult to treat, and there is no proven efficient treatment. Various risk factors have been correlated with postpneumonectomy pulmonary edema onset. Fluid overload was the first to be identified as a factor to avoid. However, many studies have shown that there is no direct correlation between fluid overload and the development of edema. Prevention is the best way to avoid postpneumonectomy pulmonary edema and must be performed in a multidisciplinary fashion, involving the entire medical staff - from the initiation of anesthesia through the surgical procedure and extending into the critical care management phase. Equally important is early identification and testing of patients at risk for postpneumonectomy pulmonary edema when there is clinical suspicion of this serious complication.

Keywords: Key Words: Pulmonary edema/complications. Pneumonectomy/adverse effects. Risk factors. Pulmonary edema/prevention & control.

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.

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.

Here, we report high-resolution computed tomography (HRCT) findings in a patient who developed sudden hemoptysis, dyspnea and chest pain after smoking crack cocaine. Chest X-rays showed consolidations, primarily in the upper lobes, and HRCT scans showed ground glass attenuation opacities, consolidations and air-space nodules. A follow-up CT, after drug use discontinuation and administration of corticosteroids, showed partial resolution of pulmonary lesions and the appearance of cavitations. Clinical, imaging and laboratory findings led to a diagnosis of 'crack lung'.

Keywords: Crack cocaine/adverse effects; Cocaine-related disorders; Tomography, X-ray computed; Street drugs/adverse effects;

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.

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.

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.

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 identify the characteristics of thoracic calcifications on magnetic resonance (MR) imaging, as well as correlations between MR imaging and CT findings. Methods: This was a retrospective study including data on 62 patients undergoing CT scans and MR imaging of the chest at any of seven hospitals in the Brazilian states of Rio Grande do Sul, São Paulo, and Rio de Janeiro between March of 2014 and June of 2016 and presenting with calcifications on CT scans. T1- and T2-weighted MR images (T1- and T2-WIs) were semiquantitatively analyzed, and the lesion-to-muscle signal intensity ratio (LMSIR) was estimated. Differences between neoplastic and non-neoplastic lesions were analyzed. Results: Eighty-four calcified lesions were analyzed. Mean lesion density on CT was 367 ± 435 HU. Median LMSIRs on T1- and T2-WIs were 0.4 (interquartile range [IQR], 0.1-0.7) and 0.2 (IQR, 0.0-0.7), respectively. Most of the lesions were hypointense on T1- and T2-WIs (n = 52 [61.9%] and n = 39 [46.4%], respectively). In addition, 19 (22.6%) were undetectable on T1-WIs (LMSIR = 0) and 36 (42.9%) were undetectable on T2-WIs (LMSIR = 0). Finally, 15.5% were hyperintense on T1-WIs and 9.5% were hyperintense on T2-WIs. Median LMSIR was significantly higher for neoplastic lesions than for non-neoplastic lesions. There was a very weak and statistically insignificant negative correlation between lesion density on CT and the following variables: signal intensity on T1-WIs, LMSIR on T1-WIs, and signal intensity on T2-WIs (r = −0.13, p = 0.24; r = −0.18, p = 0.10; and r = −0.16, p = 0.16, respectively). Lesion density on CT was weakly but significantly correlated with LMSIR on T2-WIs (r = −0.29, p < 0.05). Conclusions: Thoracic calcifications have variable signal intensity on T1- and T2-weighted MR images, sometimes appearing hyperintense. Lesion density on CT appears to correlate negatively with lesion signal intensity on MR images.

Keywords: Calcification, physiologic; Thorax/diagnostic imaging; Tomography, X-ray computed; Magnetic resonance imaging.

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.

Negative-pressure pulmonary edema accompanied by hemorrhage as a manifestation of upper airway obstruction is an uncommon problem that is potentially life-threatening. The principal pathophysiological mechanism involved is the generation of markedly negative intrathoracic pressure, which leads to an increase in pulmonary vascular volume and pulmonary capillary transmural pressure, creating a risk of disruption of the alveolar-capillary membrane. We report the case of an adult male with diffuse alveolar hemorrhage following acute upper airway obstruction caused by the formation of a cervical and mediastinal abscess resulting from the insertion of a metallic tracheal stent. The patient was treated through drainage of the abscess, antibiotic therapy, and positive pressure mechanical ventilation. This article emphasizes the importance of including this entity in the differential diagnosis of acute lung injury after procedures involving upper airway instrumentation.

Keywords: Hemorrhage; Pulmonary edema; Airway obstruction; Abscess; Prostheses and implants.