Claudia Mauro Mano

Pulmonary Talcosis: Imaging Findings

Talc is a mineral widely used in the ceramic, paper, plastics, rubber, paint, and cosmetic industries. Four distinct forms of pulmonary disease caused by talc have been defined. Three of them (talcosilicosis, talcoasbestosis, and pure talcosis) are associated with aspiration and differ in the composition of the inhaled substance. The fourth form, a result of intravenous administration of talc, is seen in drug users who inject medications intended for oral use. The disease most commonly affects men, with a mean age in the fourth decade of life. Presentation of patients with talc granulomatosis can range from asymptomatic to fulminant disease. Symptomatic patients typically present with nonspecific complaints, including progressive exertional dyspnea, and cough. Late complications include chronic respiratory failure, emphysema, pulmonary arterial hypertension, and cor pulmonale. History of occupational exposure or of drug addiction is the major clue to the diagnosis. The high-resolution computed tomography (HRCT) finding of small centrilobular nodules associated with heterogeneous conglomerate masses containing high-density amorphous areas, with or without panlobular emphysema in the lower lobes, is highly suggestive of pulmonary talcosis. The characteristic histopathologic feature in talc pneumoconiosis is the striking appearance of birefringent, needle-shaped particles of talc seen within the giant cells and in the areas of pulmonary fibrosis with the use of polarized light. In conclusion, computed tomography can play an important role in the diagnosis of pulmonary talcosis, since suggestive patterns may be observed. The presence of these patterns in drug abusers or in patients with an occupational history of exposure to talc is highly suggestive of pulmonary talcosis.

Exogenous lipoid pneumonia. Clinical and radiological manifestations

Lipoid pneumonia results from the pulmonary accumulation of endogenous or exogenous lipids. Host tissue reactions to the inhaled substances differ according to their chemical characteristics. Symptoms can vary significantly among individuals, ranging from asymptomatic to severe, life-threatening disease. Acute, sometimes fatal, cases can occur, but the disease is usually indolent. Possible complications include superinfection by nontuberculous mycobacteria, pulmonary fibrosis, respiratory insufficiency, cor pulmonale, and hypercalcemia. The radiological findings are nonspecific, and the disease presents with variable patterns and distribution. For this reason, lipoid pneumonia may mimic many other diseases. The diagnosis of exogenous lipoid pneumonia is based on a history of exposure to oil, characteristic radiological findings, and the presence of lipid-laden macrophages on sputum or BAL analysis. High-resolution computed tomography (HRCT) is the best imaging modality for the diagnosis of lipoid pneumonia. The most characteristic CT finding in LP is the presence of negative attenuation values within areas of consolidation. There are currently no studies in the literature that define the best therapeutic option. However, there is a consensus that the key measure is identifying and discontinuing exposure to the offending agent. Treatment in patients without clinical symptoms remains controversial, but in patients with diffuse pulmonary damage, aggressive therapies have been reported. They include whole lung lavage, systemic corticosteroids, and thoracoscopy with surgical debridement.

Pulmonary tuberculosis associated with the reversed halo sign on high-resolution CT

We describe the case of a 32-year-old woman with pulmonary tuberculosis in whom a high-resolution CT scan demonstrated the reversed halo sign. The diagnosis of tuberculosis was made by lung biopsy and the detection of acid-fast bacilli in the sputum smear and culture. Follow-up assessment revealed a significant improvement in the lesions.

Lipoid pneumonia in 53 patients after aspiration of mineral oil: comparison of high-resolution computed tomography findings in adults and children.

Objective: To evaluate the high-resolution computed tomography (HRCT) findings in 53 patients with exogenous lipoid pneumonia and to compare the imaging features of adults and children. Materials and Methods: The study included 35 children and 18 adults. Statistical comparisons of findings in the 2 age groups were performed using either Pearson &khgr;2 or Fisher exact test, as appropriate, at 5% significance level. Results: The main HRCT findings included air-space consolidation, ground glass attenuation, air-space nodules, and crazy-paving pattern. Abnormalities predominated in the posterior regions of the right lung. The right lower lobe was most likely to show severe involvement. Conclusions: The presence of air-space consolidation, the involvement of upper right lobe, and the central and posterior distribution of the lesions were more common in children, whereas the crazy-paving pattern and random localization were significantly more frequent in adults. The other findings were not different between the 2 groups.

Influenza A (H1N1) virus-associated pneumonia: High-resolution computed tomography–pathologic correlation

OBJECTIVE The purpose of this study was to describe the high-resolution computed tomography (HRCT) features of fatal cases of Influenza A (H1N1) virus-associated pneumonia and to correlate them with pathologic findings. METHODS The study included six adult patients who died following Influenza A (H1N1) virus-associated pneumonia. All patients had undergone HRCT, and the images were retrospectively analyzed by two chest radiologists, who reached decisions by consensus. Two experienced lung pathologists reviewed all pathological specimens. The HRCT findings were correlated with the histopathologic data. RESULTS The predominant HRCT findings included areas of airspace consolidation (n=6) and ground-glass opacities (n=3). The main pathological features consisted of diffuse alveolar damage with hyaline membrane formation (n=5), associated with various degrees of pulmonary congestion, edema, hemorrhage, inflammatory infiltration and bronchiolitis. A patient who survived longer showed findings of organizing pneumonia. CONCLUSION Fatal cases of Influenza A (H1N1) virus-associated pneumonia can present as areas of consolidation on CT, with or without ground-glass opacities. These abnormalities can be pathologically correlated with diffuse alveolar damage. Patients with longer survival may present with findings of organizing pneumonia.

Paracoccidioidomycosis: High-resolution computed tomography–pathologic correlation

OBJECTIVE The purpose of this study was to describe the high-resolution computed tomography (HRCT) features of pulmonary paracoccidioidomycosis and to correlate them with pathologic findings. METHODS The study included 23 adult patients with pulmonary paracoccidioidomycosis. All patients had undergone HRCT, and the images were retrospectively analyzed by two chest radiologists, who reached decisions by consensus. An experienced lung pathologist reviewed all pathological specimens. The HRCT findings were correlated with histopathologic data. RESULTS The predominant HRCT findings included areas of ground-glass opacities, nodules, interlobular septal thickening, airspace consolidation, cavitation, and fibrosis. The main pathological features consisted of alveolar and interlobular septal inflammatory infiltration, granulomas, alveolar exudate, cavitation secondary to necrosis, and fibrosis. CONCLUSION Paracoccidioidomycosis can present different tomography patterns, which can involve both the interstitium and the airspace. These abnormalities can be pathologically correlated with inflammatory infiltration, granulomatous reaction, and fibrosis.

The reversed halo sign: another atypical manifestation of sarcoidosis.

We read with great interest the well-written and informative pictorial essay by Park et al. (1), which reviews the thoracic manifestations of sarcoidosis, classifying them as typical and atypical. They indicate that the less frequent and unusual manifestations may be observed in 25% to 30% of cases, emphasizing the difficulty to differentiate sarcoidosis from other diseases, and the importance of understanding the radiological manifestations of sarcoidosis in making a proper diagnosis. We would like to add another atypical aspect of the disease, recently reported by Kumazoe et al. (2) and also observed by us, which is the reversed halo sign (RHS). The RHS is defined as a focal, rounded area of groundglass surrounded by an approximately complete ring of consolidation. This sign was described by Kim et al. (3) as a finding that was relatively specific to making a diagnosis for cryptogenic organizing pneumonia (COP). Later, various authors demonstrated the presence of this sign in a wide spectrum of diseases (4), including infectious (paracoccidioidomycosis, tuberculosis, zygomycosis, and aspergillosis, among others) and non-infectious conditions (Wegener’s granulomatosis, lymphomatoid granulomatosis, and bronchioloalveolar carcinoma, among other processes). Therefore, the RHS must be regarded as a nonspecific sign that is encountered in various pulmonary diseases. Also, it may correspond to secondary organizing pneumonia in numerous conditions, as a response to the primary disease. In the case reported by Kumazoe et al. (2), the high resolution CT (HRCT) images showed multiple central ground-glass opacities surrounded by crescent or ringshaped areas of consolidation in both lungs (RHS). Moreover, the authors observed miliary nodules in the Letter to the Editor

Pulmonary hemorrhage syndrome associated with dengue fever, High-resolution computed tomography findings: a case report

Dengue hemorrhagic fever is an acute infectious disease caused by dengue virus. We described the high-resolution CT findings in a 70-year-old male with the disease, which was diagnosed by clinical examination and confirmed by serological methods. High-resolution CT demonstrated bilateral areas of consolidation with air bronchogram and ground glass opacities, as well as small bilateral pleural effusions. Dengue hemorrhagic fever should be considered in the differential diagnosis of diffuse pulmonary hemorrhage.

Follow-up aspects of influenza A (H1N1) virus-associated pneumonia: the role of high-resolution computed tomography in the evaluation of the recovery phase.

We read with great interest the manuscript written by Lee et al. (1), who described the imaging findings of pulmonary complications in two patients with influenza A (H1N1) infection. The first patient showed ill-defined ground-glass opacity nodules and patchy areas of groundglass attenuation. The second, with secondary bacterial pneumonia, showed bilateral areas of lobar consolidation and ground-glass opacities. In addition, some other reports describing the imaging features, especially on high-resolution computed tomography (HRCT), have been published in the last months (2). The predominant HRCT findings reported bilateral, peripheral, ground-glass opacities and/or bilateral areas of consolidation. The patients who presented with consolidations had a more severe clinical course (2). Limited data are available, however, on the tomographic or pathological aspects observed during the recovery phase after H1N1 infection. However, the information available on pneumonias caused by other strains of the Influenza A virus allow us to presume similarities with the behavior of H1N1. In the early stages, features of diffuse alveolar damage are predominant. Later stages may show typical changes of organization and fibrosis, including interstitial fibrosis, and bronchiolitis obliterans with or without evidence of organizing pneumonia (3). Recently, Gill et al. (4) described the pulmonary pathologic findings of 34 people who died following confirmed H1N1 infection. Twentyfive patients showed focal to extensive diffuse alveolar damage (DAD). Of these, 16 cases showed only acute DAD, seven showed acute and organizing DAD, and two had fibrosing and organizing DAD (average hospitalization time: 31.5 days). During the treatment and recovery phases, persistent opacities on radiographs may not be informative enough to distinguish disease progression from healing. HRCT may play a role in the detection and characterization of the disease, in monitoring the disease progress and response to treatment, as well as in the identification of complications. We have recently followed a patient treated for H1N1 virus-associated pneumonia, whose condition improved. The initial HRCT showed consolidations and ground-glass opacities. A follow-up examination conducted at one month, during convalescence, showed marked improvement in cough; however, dyspnea on exertion persisted. A follow-up scan performed in this phase revealed an almost complete remission of the lesions, as well as the development of linear opacities in the same location. These opacities probably represent the stage of organizing pneumonia. The patient was then treated with corticosteroids and became asymptomatic. An additional follow-up HRCT performed three months after the onset of the symptoms was normal. In conclusion, although pulmonary opacities secondary to H1N1 infection usually regress during convalescence, the consolidations may occasionally progress to linear opacities (parenchymal bands). These linear opacities probably represent organizing pneumonia.

Swine-Origin Influenza A (H1N1) Viral Infection: Small Airways Disease

AJR 2010; 195:W317 0361–803X/10/1954–W317