Arthur Soares Souza

Reversed Halo Sign: High-Resolution CT Scan Findings in 79 Patients

BACKGROUND The purpose of this study was to evaluate the high-resolution CT (HRCT) scan findings of patients with the reversed halo sign (RHS) and to identify distinguishing features among the various causes. METHODS Two chest radiologists reviewed the HRCT scans of 79 patients with RHS and determined the CT scan findings by consensus. We studied the morphologic characteristics, number of lesions, and presence of features associated with RHS. RESULTS Forty-one patients presented with infectious diseases (paracoccidioidomycosis, TB, zygomycosis, invasive pulmonary aspergillosis, Pneumocystis jiroveci pneumonia, histoplasmosis, cryptococcosis), and 38 presented with noninfectious diseases (cryptogenic organizing pneumonia, pulmonary embolism, sarcoidosis, edema, lepidic predominant adenocarcinoma [formerly bronchiolo-alveolar carcinoma], granulomatosis with polyangiitis [Wegener]). The RHS walls were smooth in 58 patients (73.4%) and nodular in 21 patients (26.6%). Lesions were multiple in 40 patients (50.6%) and single in 39 patients (49.4%). CONCLUSION The presence of nodular walls or nodules inside the halo of the RHS is highly suggestive of granulomatous diseases.

High-Resolution CT Findings of 77 Patients with Untreated Pulmonary Paracoccidioidomycosis

OBJECTIVE The objective of our study was to describe the high-resolution CT findings of 77 patients with pulmonary paracoccidioidomycosis (PCM) who had not yet been treated for PCM. MATERIALS AND METHODS The high-resolution CT scans of 77 consecutive patients with proven pulmonary PCM were reviewed by two chest radiologists, and decisions regarding the CT findings were reached by consensus. Seventy-one of the patients were men and six were women, with an average age of 49 years. The criteria for interpretation of the high-resolution CT scans are defined in the Fleischner Societys Glossary of Terms. RESULTS The most frequent high-resolution CT findings were ground-glass attenuation areas (58.4%), small centrilobular nodules (45.5%), cavitated nodules (42.9%), large nodules (41.6%), parenchymal bands (33.8%), areas of cicatricial emphysema (33.8%), interlobular septal thickening (31.2%), and architectural distortion (29.9%). Most of these high-resolution CT findings predominated at the periphery (53%) and posterior (88%) regions involving all lung zones, with discrete predominance in the middle zones (35%). CONCLUSION The high-resolution CT findings of patients with pulmonary PCM who have not yet been treated consist of ground-glass attenuation areas associated with small centrilobular nodules, cavitated nodules, large nodules, parenchymal bands, and areas of cicatricial emphysema. These abnormalities are usually distributed in the posterior and peripheral regions of the lungs, with discrete predominance in the middle lung zones.

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.

Silicoproteinosis: High-Resolution CT Findings in 13 Patients

OBJECTIVE The purpose of this study was to evaluate the high-resolution CT findings of silicoproteinosis. CONCLUSION Silicoproteinosis usually manifests as bilateral consolidation in the posterior portions of the lungs and as numerous centrilobular nodules. Calcification within areas of consolidation is a common finding.

The Reversed Halo Sign on High-Resolution CT in Infectious and Noninfectious Pulmonary Diseases

OBJECTIVE The purpose of this article is to describe diseases that may present with the reversed halo sign on high-resolution CT. We emphasize the tomographic features most frequently associated with this sign and correlate them with histologic findings. CONCLUSION A wide spectrum of infectious and noninfectious diseases may present with the reversed halo sign on chest CT. The nonspecific nature of this sign should not cloud an otherwise fairly straightforward diagnosis, especially when associated background findings are typical. Although a rigorous analysis of associated CT findings may help with the differential diagnosis, histologic assessment is often needed for a definitive determination of the cause.

Unusual manifestations of metastatic pulmonary calcification: high-resolution CT and pathological findings.

The aim of this report is to describe the high-resolution CT and pathologic findings of 3 patients with unusual manifestations of metastatic pulmonary calcification. These include a case that presented with extensive dense consolidation, a case of metastatic calcification that improved spontaneously, and a case of metastatic calcification in a patient with no demonstrable biochemical abnormality or underlying disease. We conclude that metastatic calcification may present with dense bilateral consolidation, may improve spontaneously, and may rarely present in patients with no apparent underlying biochemical abnormality.

Metastatic pulmonary calcification: State-of-the-art review focused on imaging findings

Metastatic pulmonary calcification (MPC) is a subdiagnosed metabolic lung disease that is commonly associated with end-stage renal disease. This interstitial process is characterized by the deposition of calcium salts predominantly in the alveolar epithelial basement membranes. MPC is seen at autopsy in 60-75% of patients with renal failure. It is often asymptomatic, but can potentially progress to respiratory failure. Chest radiographs are frequently normal or demonstrate confluent or patchy airspace opacities. Three patterns visible on high-resolution computed tomography have been described: multiple diffuse calcified nodules, diffuse or patchy areas of ground-glass opacity or consolidation, and confluent high-attenuation parenchymal consolidation. The relative stability of these pulmonary infiltrates, in contrast to infectious processes, and their resistance to treatment, in the clinical context of hypercalcemia, are of diagnostic value. Scintigraphy with bone-seeking radionuclides may demonstrate increased radioactive isotope uptake. The resolution of pulmonary calcification in chronic renal failure may occur after parathyroidectomy, renal transplantation, or dialysis. Thus, the early diagnosis of MPC is beneficial. The aim of this review is to describe the main clinical, pathological, and imaging aspects of MPC.

Correlation between computed tomographic and magnetic resonance imaging findings of parenchymal lung diseases.

Computed tomography (CT) is considered to be the gold standard method for the assessment of morphological changes in the pulmonary parenchyma. Although its spatial resolution is lower than that of CT, MRI offers the advantage of characterizing different aspects of tissue based on the degree of contrast on T1-weighted image (WI) and T2-WI. In this article, we describe and correlate the MRI and CT features of several common patterns of parenchymal lung disease (air trapping, atelectasis, bronchiectasis, cavitation, consolidation, emphysema, ground-glass opacities, halo sign, interlobular septal thickening, masses, mycetoma, nodules, progressive massive fibrosis, reverse halo sign and tree-in-bud pattern). MRI may be an alternative modality for the collection of morphological and functional information useful for the management of parenchymal lung disease, which would help reduce the number of chest CT scans and radiation exposure required in patients with a variety of conditions.

Can chest high-resolution computed tomography findings diagnose pulmonary alveolar microlithiasis?

Objective The present study was aimed at retrospectively reviewing high-resolution computed tomography (HRCT) findings in patients with pulmonary alveolar microlithiasis in order to evaluate the frequency of tomographic findings and their distribution in the lung parenchyma. Materials and Methods Thirteen patients (9 females and 4 males; age, 9 to 59 years; mean age, 34.5 years) were included in the present study. The HRCT images were independently evaluated by two observers whose decisions were made by consensus. The inclusion criterion was the presence of abnormalities typical of pulmonary alveolar microlithiasis at HRCT, which precludes lung biopsy. However, in 6 cases lung biopsy was performed. Results Ground-glass opacities and small parenchymal nodules were the predominant tomographic findings, present in 100% of cases, followed by small subpleural nodules (92.3%), subpleural cysts (84.6%), subpleural linear calcifications (69.2%), crazy-paving pattern (69.2%), fissure nodularity (53.8%), calcification along interlobular septa (46.2%) and dense consolidation (46.2%). Conclusion As regards distribution of the lesions, there was preferential involvement of the lower third of the lungs. No predominance of distribution in axial and anteroposterior directions was observed.

Ressonância magnética de pulmão: um novo passo no estudo das doenças pulmonares*

Magnetic resonance imaging (MRI) of the lung has progressed tremendously in recent years. Because of improvements in speed and image quality, MRI is now ready for routine clinical use. The main advantage of MRI of the lung is its unique combination of structural and functional assessment in a single imaging session. We review the three major clinical indications for MRI of the lung: staging of lung tumors; evaluation of pulmonary vascular disease; and investigation of pulmonary abnormalities in patients who should not be exposed to radiation.