Importance of chest HRCT in the diagnostic evaluation of fibrosing interstitial lung diseases.

Many conditions result in chronic interstitial lung disease (ILD), being classified as fibrosing ILDs, including idiopathic pulmonary fibrosis, connective tissue diseases, sarcoidosis, and fibrotic hypersensitivity pneumonitis. HRCT plays an important role in the clinical evaluation of fibrosing ILDs. Current treatment perspectives are encouraging and reinforce the need for HRCT scans of adequate technical quality for early detection of fibrosing ILD. Despite efforts in this regard, the significance and management of imaging findings of early interstitial lung abnormalities have yet to be clarified. After identification of CT findings consistent with fibrosing ILD, radiologists must be able to identify characteristic morphological patterns and, in some cases, features of specific clinical entities. In cases in which HRCT features are not sufficiently specific for a definitive diagnosis, HRCT can aid in selecting the best site for surgical lung biopsy. CT follow-up is useful for identifying progressive fibrosing ILDs and detecting complications unrelated to the underlying disease, including infections, acute exacerbations, and neoplasms. Automated quantification tools have clinical applicability and are likely to be available for use in imaging analysis in the near future. In addition, incorporation of CT evaluation into scoring systems based on clinical and functional parameters for staging fibrosing disease is likely to become valuable in determining prognosis. Knowledge of the clinical applications of CT evaluation is essential for specialists managing patients with fibrosing ILD and can have a positive impact on the clinical course of the disease.

High-resolution computed tomography and histopathological findings in hypersensitivity pneumonitis: a pictorial essay.

Hypersensitivity pneumonitis is a diffuse interstitial and granulomatous lung disease caused by the inhalation of any one of a number of antigens. The objective of this study was to illustrate the spectrum of abnormalities in high-resolution computed tomography and histopathological findings related to hypersensitivity pneumonitis. We retrospectively evaluated patients who had been diagnosed with hypersensitivity pneumonitis (on the basis of clinical-radiological or clinical-radiological-pathological correlations) and had undergone lung biopsy. Hypersensitivity pneumonitis is clinically divided into acute, subacute, and chronic forms; high-resolution computed tomography findings correlate with the time of exposure; and the two occasionally overlap. In the subacute form, centrilobular micronodules, ground-glass opacities, and air trapping are characteristic high-resolution computed tomography findings, whereas histopathology shows lymphocytic inflammatory infiltrates, bronchiolitis, variable degrees of organizing pneumonia, and giant cells. In the chronic form, high-resolution computed tomography shows traction bronchiectasis, honeycombing, and lung fibrosis, the last also being seen in the biopsy sample. A definitive diagnosis of hypersensitivity pneumonitis can be made only through a multidisciplinary approach, by correlating clinical findings, exposure history, high-resolution computed tomography findings, and lung biopsy findings.

A pneumonite por hipersensibilidade é uma doença intersticial difusa, granulomatosa e de natureza inalatória, com inúmeros antígenos orgânicos e inorgânicos implicados. Nosso objetivo é ilustrar o espectro de anormalidades na tomografia de alta resolução do tórax e achados histopatológicos. Foram avaliadas, retrospectivamente, tomografias de alta resolução do tórax de pacientes com diagnóstico de pneumonite por hipersensibilidade estabelecido em correlação clínico-radiológica e clínico-radiológico-patológica em pacientes em que a biópsia esteve disponível. A pneumonite por hipersensibilidade é dividida, do ponto de vista clínico e didático, em aguda, subaguda e crônica, e as manifestações tomográficas da tomografia de alta resolução do tórax correlacionam-se com o tempo da evolução da doença, e por vezes se superpõem. Micronódulos centrolobulares, vidro fosco e aprisionamento aéreo são características tomográficas na manifestação subaguda, em que, histopatologicamente, se observam infiltrado inflamatório linfocítico, bronquiolite, graus variáveis de pneumonia em organização e células gigantes. Na fase crônica, a tomografia demonstra sinais de fibrose com bronquiolectasias de tração e eventualmente faveolamento, com predomínio superior, sendo observados também sinais de fibrose no estudo histopatológico. A abordagem multidisciplinar é definitiva no diagnóstico, que é realizado correlacionando-se as características clínicas, nexo causal de exposição, achados tomográficos e aspectos histopatológicos.

High-resolution computed tomography and histopathological findings in hypersensitivity pneumonitis: a pictorial essay / Aspectos tomográficos e histopatológicos da pneumonite por hipersensibilidade: ensaio iconográfico

Abstract Hypersensitivity pneumonitis is a diffuse interstitial and granulomatous lung disease caused by the inhalation of any one of a number of antigens. The objective of this study was to illustrate the spectrum of abnormalities in high-resolution computed tomography and histopathological findings related to hypersensitivity pneumonitis. We retrospectively evaluated patients who had been diagnosed with hypersensitivity pneumonitis (on the basis of clinical-radiological or clinical-radiological-pathological correlations) and had undergone lung biopsy. Hypersensitivity pneumonitis is clinically divided into acute, subacute, and chronic forms; high-resolution computed tomography findings correlate with the time of exposure; and the two occasionally overlap. In the subacute form, centrilobular micronodules, ground-glass opacities, and air trapping are characteristic high-resolution computed tomography findings, whereas histopathology shows lymphocytic inflammatory infiltrates, bronchiolitis, variable degrees of organizing pneumonia, and giant cells. In the chronic form, high-resolution computed tomography shows traction bronchiectasis, honeycombing, and lung fibrosis, the last also being seen in the biopsy sample. A definitive diagnosis of hypersensitivity pneumonitis can be made only through a multidisciplinary approach, by correlating clinical findings, exposure history, high-resolution computed tomography findings, and lung biopsy findings.

Resumo A pneumonite por hipersensibilidade é uma doença intersticial difusa, granulomatosa e de natureza inalatória, com inúmeros antígenos orgânicos e inorgânicos implicados. Nosso objetivo é ilustrar o espectro de anormalidades na tomografia de alta resolução do tórax e achados histopatológicos. Foram avaliadas, retrospectivamente, tomografias de alta resolução do tórax de pacientes com diagnóstico de pneumonite por hipersensibilidade estabelecido em correlação clínico-radiológica e clínico-radiológico-patológica em pacientes em que a biópsia esteve disponível. A pneumonite por hipersensibilidade é dividida, do ponto de vista clínico e didático, em aguda, subaguda e crônica, e as manifestações tomográficas da tomografia de alta resolução do tórax correlacionam-se com o tempo da evolução da doença, e por vezes se superpõem. Micronódulos centrolobulares, vidro fosco e aprisionamento aéreo são características tomográficas na manifestação subaguda, em que, histopatologicamente, se observam infiltrado inflamatório linfocítico, bronquiolite, graus variáveis de pneumonia em organização e células gigantes. Na fase crônica, a tomografia demonstra sinais de fibrose com bronquiolectasias de tração e eventualmente faveolamento, com predomínio superior, sendo observados também sinais de fibrose no estudo histopatológico. A abordagem multidisciplinar é definitiva no diagnóstico, que é realizado correlacionando-se as características clínicas, nexo causal de exposição, achados tomográficos e aspectos histopatológicos.