Imaging in occupational lung diseases

This chapter consists of a review of the literature regarding radiographic and tomographic characteristics of the principal occupational respiratory diseases (silicosis and asbestosis). Special attention is given to the practical relevance of high-resolution computed tomography, which is the most sensitive and specific method of identifying and quantifying the extent of pleural and parenchymal lesions related to such diseases.A presente revisão apresenta as características radiográficas e tomográficas das principais doenças ocupacionais respiratórias (silicose e asbestose). Em especial, enfatiza-se a relevância prática da tomografia computadorizada de alta resolução, método mais sensível e específico para a detecção e quantificação da extensão das lesões pleuroparenquimatosas a elas relacionadas.Universidade Federal de São Paulo (UNIFESP)Memorial Sloan-Kettering Cancer CenterUniversidade de São Paulo Faculdade de Medicina Hospital das ClínicasUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de DiagnósticoUNIFESP, EPM, Depto. de DiagnósticoSciEL

Asma persistente em adultos: comparação da tomografia computadorizada de tórax de alta resolução após um ano de seguimento

OBJECTIVE: The aims of this study were to evaluate the role of high resolution computed tomography of the torax in detecting abnormalities in chronic asthmatic patients and to determine the behavior of these lesions after at least one year. METHOD: Fourteen persistent asthmatic patients with a mean forced expiratory volume in 1-second that was 63% of predicted and a mean forced expiratory volume in 1-second /forced vital capacity of 60% had two high resolution computed tomographys separated by an interval of at least one year. RESULTS: All 14 patients had abnormalities on both scans. The most common abnormality was bronchial wall thickening, which was present in all patients on both computed tomographys. Bronchiectasis was suggested on the first computed tomography in 5 of the 14 (36%) patients, but on follow-up, the bronchial dilatation had disappeared in 2 and diminished in a third. Only one patient had any emphysematous changes; a minimal persistent area of paraseptal emphysema was present on both scans. In 3 patients, a "mosaic" appearance was observed on the first scan, and this persisted on the follow-up computed tomography. Two patients had persistent areas of mucoid impaction. In a third patient, mucus plugging was detected only on the second computed tomography. CONCLUSIONS: We conclude that there are many abnormalities on the high resolution computed tomography of patients with persistent asthma. Changes suggestive of bronchiectasis, namely bronchial dilatation, frequently resolve spontaneously. Therefore, the diagnosis of bronchiectasis by high resolution computed tomography in asthmatic patients must be made with caution, since bronchial dilatation can be reversible or can represent false dilatation. Nonsmoking chronic asthmatic subjects in this study had no evidence of centrilobular or panacinar emphysema.OBJETIVO: Avaliar o papel da tomografia computadorizada de tórax de alta resolução em detectar alterações estruturais pulmonares em pacientes asmáticos persistentes e determinar o comportamento destas lesões após pelo menos um ano de seguimento. MÉTODO: Foram avaliados 14 pacientes asmáticos persistentes em que eram disponíveis duas tomografias computadorizadas de tórax de alta resolução realizadas com um intervalo de pelo menos um ano. O valor médio do volume expiratório forçado no primeiro segundo foi de 63% do predito e o da relação volume expiratório forçado no primeiro segundo/capacidade vital forçada foi de 60%. RESULTADOS: Alterações estruturais foram detectadas em todos os pacientes em ambas tomografias. A anormalidade mais comumente observada foi espessamento brônquico, presente em todos os pacientes nos dois exames. Bronquectasias foram sugeridas na primeira tomografia em cinco dos 14 (36%) pacientes, mas no segundo exame a dilatação brônquica tinha desaparecido em dois e reduzido em um. Enfisema paraseptal foi detectado em um paciente. Em três, havia padrão "em mosaico " no primeiro exame, que persistiu no segundo exame. Em dois pacientes foram detectadas áreas persistentes de impactação mucóide. Em um terceiro, a impactação foi observada somente na segunda tomografia. CONCLUSÕES: Pacientes com asma persistente apresentam múltiplas anormalidades na tomografia computadorizada de tórax de alta resolução. Imagens sugestivas de bronquectasias freqüentemente têm resolução espontânea. Desta forma, é necessária precaução ao fazer o diagnóstico de bronquectasias através de tomografia computadorizada de tórax de alta resolução em pacientes asmáticos, uma vez que a dilatação brônquica pode ser reversível ou representar uma falsa dilatação. Enfisema centrilobular ou panacinar não foi detectado em nenhum paciente deste estudo

Identification of rounded atelectasis in workers exposed to asbestos by contrast helical computed tomography

Rounded atelectasis (RA) is a benign and unusual form of subpleural lung collapse that has been described mostly in asbestos-exposed workers. This form of atelectasis manifests as a lung nodule and can be confused with bronchogenic carcinoma upon conventional radiologic examination. the objective of the present study was to evaluate the variation in contrast uptake in computed tomography for the identification of asbestos-related RA in Brazil. Between January 1998 and December 2000, high-resolution computed tomography (HRCT) was performed in 1658 asbestos-exposed workers. the diagnosis was made in nine patients based on a history of prior asbestos exposure, the presence of characteristic (HRCT) findings and lesions unchanged in size over 2 years or more. in three of them the diagnosis was confirmed during surgery. the dynamic contrast enhancement study was modified to evaluate nodules and pulmonary masses. All nine patients with RA received iodide contrast according to weight. the average enhancement after iodide contrast was infused, reported as Hounsfield units (HU), increased from 62.5 +/- 9.7 to 125.4 +/- 20.7 (P < 0.05), with a mean enhancement of 62.5 +/- 19.7 (range 40 to 89) and with a uniform dense opacification. in conclusion, in this study all patients with RA showed contrast enhancement with uniform dense opacification. the main clinical implication of this finding is that this procedure does not permit differentiation between RA and malignant pulmonary neoplasm.Grp Interinst Estudos Doencas Relacionadas Amiant, São Paulo, BrazilUniv São Paulo, Fac Med, Hosp Clin, Inst Corcao,Disciplina Pneumol, São Paulo, BrazilUniv São Paulo, Fac Med, Disciplinas Radiol, São Paulo, BrazilUniv São Paulo, Fac Med, Disciplinas Patol, São Paulo, BrazilUniv Estadual Campinas, Fac Med, Area Med Ocupac, Campinas, SP, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Disciplinas Pneumol, São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Disciplinas Radiol, São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Disciplinas Pneumol, São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Disciplinas Radiol, São Paulo, BrazilWeb of Scienc