Silicosis chest x ray
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Silicosis chest x ray On the Web |
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American Roentgen Ray Society Images of Silicosis chest x ray |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Chest X Ray
In acute silicosis, the chest radiograph demonstrates characteristic bilateral, diffuse ground glass opacities [42,51,52]. The opacities may be perihilar or basilar [53]. These features may progress from a pattern of lower zone opacities to large masses of coalesced parenchymal tissue in the mid and lower zones, which are typically bilateral but not always symmetrical [42,53].
- A chest radiograph is obtained in virtually all patients undergoing evaluation for chronic silicosis; high resolution computed tomography (HRCT) is helpful for patients with an atypical clinical presentation or atypical findings on chest radiograph. In our occupational lung disease specialty clinic, we often obtain a baseline HRCT scan in patients with radiographic findings of silicosis to document the presence and extent of nodules, emphysema, and other silica-related abnormalities that may progress in the future.
●Chest radiograph – The typical chest radiograph finding in chronic simple silicosis is the presence of innumerable, small, rounded opacities (less than 10 mm in diameter). The nodules are generally rounded but can be irregular, and are distributed predominantly in the upper lung zones (image 3A-B). Progressive massive fibrosis (PMF, also known as conglomerate silicosis) occurs when these small opacities gradually enlarge and coalesce to form larger, upper- or mid-zone opacities more than 10 mm in diameter (image 4) [22]. As these opacities progressively enlarge, the hila are retracted upward in association with upper lobe fibrosis and lower lobe hyperinflation. The opacities of PMF can be asymmetrical, and may mimic a neoplastic process. Cavitation may also be present in advanced disease or in the setting of mycobacterial superinfection. Hilar adenopathy with prominent calcification is present in up to 5 percent of workers with silicosis. (See "Imaging of occupational lung diseases", section on 'Silicosis'.)
Several reports have compared the accuracy of the chest radiograph appearance to pathologic examination of the lungs at autopsy in detecting silicosis. In a study of more than 500 South African gold miners, when radiographs were scored using the International Labor Office (ILO) classification system profusion classes of 1/0, 1/1, and 1/2 as cutoffs, sensitivities were found to be 50, 37, and 25 percent, respectively, and specificities 89, 96, and 100 percent, respectively [72]. A subsequent smaller study of 241 South African gold miners evaluated use of "miniradiographs" with cutoffs at ILO profusion categories 0/1, 1/0, and 1/1. Sensitivities were 89, 74, and 71 percent, respectively, and specificities were 73, 87, and 96 percent, respectively [73]. Reasons for improved sensitivity in the second study were unclear. (See "Imaging of occupational lung diseases", section on 'The International Labor Office classification' and "Evaluation of diffuse lung disease by conventional chest radiography".) Chest x-ray will confirm the presence of nodules in the lungs, especially in the upper lobes. Typically, it will also reveal eggshell calcification of the hilar lymph nodes. In rare cases, pulmonary nodules may also be calcified. In advanced cases of silicosis, coalescence of nodules may show up as large masses.
