Gustavo de Souza Portes Meirelles

High-resolution computed tomography findings from adult patients with Influenza A (H1N1) virus-associated pneumonia

OBJECTIVE The aim of this study was to assess the high-resolution computed tomography (HRCT) findings at presentation in patients diagnosed with Influenza A (H1N1) virus-associated pneumonia. MATERIALS AND METHODS We reviewed the HRCT findings from 20 patients diagnosed with Influenza A (H1N1) and compared their HRCT scans with chest radiographs, obtained on the same day. The imaging studies were obtained 4-9 days after the onset of symptoms. The patients included 11 men and 9 women (ages 24-62 years; mean 42.7 years). All patients had a body temperature greater than 100.4 degrees F (>38 degrees C), tachypnea, and cough. Other common symptoms included diarrhea (60%) and sore throat (30%). The radiographs and HRCT scans were reviewed independently by two observers who reached a consensus decision. RESULTS The predominant HRCT findings consisted of bilateral ground-glass opacities (n=12), bilateral areas of consolidation (n=2), or a mixed bilateral pattern of ground-glass opacities and areas of consolidation (n=6). The abnormalities were bilateral in all of the 20 patients, had a predominantly sub-pleural distribution in 13 patients, and had a random distribution in the remaining 7 patients. The predominant radiographic findings were consolidations. Normal radiographs were found in 4 out of the 20 patients. CONCLUSION HRCT may reveal parenchymal abnormalities in patients with Influenza A (H1N1) infection who have normal findings on radiographs. The predominant HRCT findings were bilateral, peripheral, ground-glass opacities and/or bilateral areas of consolidation. The patients who presented consolidations had more severe clinical course.

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.

Thoracic Manifestations of Collagen Vascular Diseases

Collagen vascular diseases are a diverse group of immunologically mediated systemic disorders that often lead to thoracic changes. The collagen vascular diseases that most commonly involve the lung are rheumatoid arthritis, progressive systemic sclerosis, systemic lupus erythematosus, polymyositis and dermatomyositis, mixed connective tissue disease, and Sjögren syndrome. Interstitial lung disease and pulmonary arterial hypertension are the main causes of mortality and morbidity among patients with collagen vascular diseases. Given the broad spectrum of possible thoracic manifestations and the varying frequency with which different interstitial lung diseases occur, the interpretation of thoracic images obtained in patients with collagen vascular diseases can be challenging. The task may be more difficult in the presence of treatment-related complications such as drug toxicity and infections, which are common in this group of patients. Although chest radiography is most often used for screening and monitoring of thoracic alterations, high-resolution computed tomography can provide additional information about lung involvement in collagen vascular diseases and may be especially helpful for differentiating specific disease patterns in the lung. General knowledge about the manifestations of thoracic involvement in collagen vascular diseases allows radiologists to provide better guidance for treatment and follow-up of these patients.

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.

Swine-Origin Influenza A (H1N1) Viral Infection: Thoracic Findings on CT

OBJECTIVE The purpose of this article is to illustrate and describe various CT manifestations of swine-origin influenza A (H1N1) viral infection. CONCLUSION The imaging findings seen in patients with H1N1 infection include consolidations, ground-glass opacities, interlobular septal thickening, small nodules, and findings suggestive of small airways disease, among others. Definitive diagnosis is based on correlation of the CT findings with the clinical symptoms and laboratory test results.

Comparative study of clinical, pathological and HRCT findings of primary alveolar proteinosis and silicoproteinosis

OBJECTIVE To compare the clinical, high-resolution computed tomography (HRCT) and pathological findings of primary alveolar proteinosis (PAP) and silicoproteinosis. MATERIAL AND METHODS The study included 15 patients with PAP (6 women, 9 men, mean age 31 years) and 13 with silicoproteinosis (13 men, mean age 29.5 years). PAP was diagnosed by lung biopsy in 13 and bronchoalveolar lavage in two patients and silicoproteinosis by bronchoalveolar lavage in 10 and autopsy in three cases. HRCT images were reviewed by two chest radiologists with consensus for the presence, extent and distribution of ground-glass opacities, septal thickening, consolidation and nodules. Radiological-pathological correlation was performed by one radiologist and one chest pathologist. RESULTS Seven (46%) patients with PAP were asymptomatic; the remainder presented slowly progressive dyspnea and dry cough. All silicoproteinosis patients had dry cough and rapidly progressive dyspnea. The most common HRCT finding on PAP was the crazy-paving pattern (93%). All cases had areas of geographic sparing in the affected lung. The most common finding in silicoproteinosis (92%) was dependent consolidation with calcification in 83%. Centrilobular nodules were common (85%). On pathology, both diseases demonstrated intra-alveolar accumulation of PAS material, thickening of interlobular septae and alveolar walls and no evidence of fibrosis. A few silica particles were seen in silicoproteinosis. CONCLUSION Despite the pathological similarities, PAP and silicoproteinosis have distinct clinical and imaging features and prognosis. Bilateral crazy-paving pattern with areas of geographic sparing is characteristic for PAP. Silicoproteinosis presents with bilateral dependent consolidation often with areas of calcification. The crazy-paving pattern is not seen in silicoproteinosis.

Hematopoese extramedular: achados em tomografia computadorizada do tórax de 6 pacientes

OBJETIVO: Apresentar os achados na tomografia computadorizada do torax indicativos de hematopoese extramedular de seis pacientes. METODOS: Foram estudadas, retrospectivamente, as tomografias de seis pacientes adultos-cinco homens e uma mulher-com idade media de 36,5 anos. Os exames foram analisados por dois radiologistas, de forma independente, e as decisoes finais foram obtidas por consenso. RESULTADOS: O achado mais frequente nas tomografias foi o de massas paravertebrais inferiores, de conteudo heterogeneo (quatro pacientes). As tomografias de dois pacientes mostravam uma massa solitaria parietal e pleural. CONCLUSOES: A hematopoese extramedular apresenta aspectos na tomografia computadorizada fortemente sugestivos do diagnostico que, quando correlacionados com a presenca de doenca hematologica de base, permitem, na maior parte dos casos, dispensar a comprovacao histopatologica.

Observer agreement in the diagnosis of interstitial lung diseases based on HRCT scans

OBJECTIVE To determine the interobserver and intraobserver agreement in the diagnosis of interstitial lung diseases (ILDs) based on HRCT scans and the impact of observer expertise, clinical data and confidence level on such agreement. METHODS Two thoracic radiologists and two general radiologists independently reviewed the HRCT images of 58 patients with ILDs on two distinct occasions: prior to and after the clinical anamnesis. The radiologists selected up to three diagnostic hypotheses for each patient and defined the confidence level for these hypotheses. One of the thoracic and one of the general radiologists re-evaluated the same images up to three months after the first readings. In the coefficient analyses, the kappa statistic was used. RESULTS The thoracic and general radiologists, respectively, agreed on at least one diagnosis for each patient in 91.4% and 82.8% of the patients. The thoracic radiologists agreed on the most likely diagnosis in 48.3% (kappa = 0.42) and 62.1% (kappa = 0.58) of the cases, respectively, prior to and after the clinical anamnesis; likewise, the general radiologists agreed on the most likely diagnosis in 37.9% (kappa = 0.32) and 36.2% (kappa = 0.30) of the cases. For the thoracic radiologist, the intraobserver agreement on the most likely diagnosis was 0.73 and 0.63 prior to and after the clinical anamnesis, respectively. That for the general radiologist was 0.38 and 0.42.The thoracic radiologists presented almost perfect agreement for the diagnostic hypotheses defined with the high confidence level. CONCLUSIONS Interobserver and intraobserver agreement in the diagnosis of ILDs based on HRCT scans ranged from fair to almost perfect and was influenced by radiologist expertise, clinical history and confidence level.

Recurrent respiratory papillomatosis with pulmonary involvement

1. Departamento de Diagnostico por Imagem, Escola Paulista de Medicina, Universidade Federal de Sao Paulo, Sao Paulo, SP. 2. Centro de Medicina Diagnostica Fleury, Sao Paulo, SP. Address to: Dr. Gustavo de Souza Portes Meirelles. Alameda Itu 78/1404, 01421-000 Sao Paulo, SP. e-mail: gmeirelles@gmail.com Recebido para publicacao em: 16/07/2007 Aceito em: 11/10/2007 IMAGENS EM DIP/IMAGES IN INFECTIOUS DISEASE

Screening of miners and millers at decreasing levels of asbestos exposure: comparison of chest radiography and thin-section computed tomography.

Background Chest radiography (CXR) is inferior to Thin-section computed tomography in the detection of asbestos related interstitial and pleural abnormalities. It remains unclear, however, whether these limitations are large enough to impair CXR´s ability in detecting the expected reduction in the frequency of these asbestos-related abnormalities (ARA) as exposure decreases. Methods Clinical evaluation, CXR, Thin-section CT and spirometry were obtained in 1418 miners and millers who were exposed to progressively lower airborne concentrations of asbestos. They were separated into four groups according to the type, period and measurements of exposure and/or procedures for controlling exposure: Group I (1940–1966/tremolite and chrysotile, without measurements of exposure and procedures for controlling exposure); Group II (1967–1976/chrysotile only, without measurements of exposure and procedures for controlling exposure); Group III (1977–1980/chrysotile only, initiated measurements of exposure and procedures for controlling exposure) and Group IV (after 1981/chrysotile only, implemented measurements of exposure and a comprehensive procedures for controlling exposure). Results In all groups, CXR suggested more frequently interstitial abnormalities and less frequently pleural plaques than observed on Thin-section CT (p<0.050). The odds for asbestosis in groups of decreasing exposure diminished to greater extent at Thin-section CT than on CXR. Lung function was reduced in subjects who had pleural plaques evident only on Thin-section CT (p<0.050). In a longitudinal evaluation of 301 subjects without interstitial and pleural abnormalities on CXR and Thin-section CT in a previous evaluation, only Thin-section CT indicated that these ARA reduced as exposure decreased. Conclusions CXR compared to Thin-section CT was associated with false-positives for interstitial abnormalities and false-negatives for pleural plaques, regardless of the intensity of asbestos exposure. Also, CXR led to a substantial misinformation of the effects of the progressively lower asbestos concentrations in the occurrence of asbestos-related diseases in miners and millers.