Micronodule subpleural

Fig. 26.21. A 37-year-old man with pulmonary alveolar microlithiasis. Axial CT image shows miliary distributed calcified micronodules predominantly located in the middle and lower zones of both lungs. Also note the formation of small subpleural cysts and subpleural emphysema and the formation of the pathognomonic black subpleural line (white arrows)...

Fig. 6.8a,b. Coal worker s pneumoconiosis computed tomography scan showing mild micronodular lung and subpleural involvement, a Axial view with slice thickness of 1 mm.b Coronal reconstruction with slice thickness of 3 mm. Micronodules are seen in the upper part of the right lung. Notice also the presence of a few subpleural micronodules (arrows)... 

Subpleural micronodules are closely related to the subpleural lymphatic system and present on CT as rounded, hemispheric or triangular opacities with a diameter less than 7 mm (Remy-Jardin et al. 1992) in the peripheral and fissural subpleural areas (Fig. 6.8, Fig 6.9). These micronodules are seen in the majority of coal miners with radiographic evidence of CWP, although with thin-section CT, they are often depicted in miners without radiographic... 

The subpleural micronodules can merge, and subpleural focal linear areas of increased opacity develop (Fig. 6.10). These pseudo plaques have a diameter of less than 7 mm and should be differentiated from real plaques , which are focal areas of fibrous thickening on the parietal pleura and occur in response to asbestos exposure. The differential diagnosis is based on the distribution of these pleural abnormalities asbestos exposure-related plaques are usually located in the dorsal and posterior part of the chest when involvement is mild and extend towards the anterior chest wall when diseases become more pronounced. Sometimes the pseudo plaque is separated from the chest wall by small emphysematous areas and then presents as a tubular opacity parallel to the chest wall (Remy-Jardin et al. 1992). 

Remy-Jardin M, Beuscart R, Sault MC, Marquette CH, Remy J (1990a) Subpleural micronodules in diffuse infiltrative lung diseases evaluation with thin section CT scans. Radiology 177 133-139... 

Nodules are seen in about 60% of cases, often clustered together around the bronchi, interlobular septa, or in the subpleural region (Fig. 10.5) (Newman, Buschman et al. 1994). Subpleural clusters of nodules may form pseudo-plaques, and pleural irregularity is found in about 25%. As in sarcoidosis, even small subpleural nodules maybe readily visible along the major fissures (Fig. 10.5). Although the nodules are usually well defined and 2-5 mm in size, fine micronodules, quite similar to those found in hypersensitivity pneumonitis, may also be seen (Fig. 10.6). 

Fig. 3. 33. Cytomegalovirus pneumonia. CT ofthe lung shows a ground-glass opacification predominating in the upper lobes with subpleural micronodules on the right side...

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