Pleuritic fibrinous exudation, granulation tissue hyperplasia, and organized hematoma resulting from traumatic hemorrhage can cause pleural thickening, adhesion, and calcification. Pleural thickening and adhesion often exist simultaneously. Mild localized pleural thickening and adhesion often occur in the costophrenic angle. Pleural calcification is common in tuberculous pleurisy, organized hematoma, and pneumoconiosis.
X-ray
In localized pleural thickening and adhesion, chest x-ray often shows shallow and flattened costophrenic angle. In extensive pleural thickening and adhesion, collapsed thorax on the affected side can be seen, the intercostal space narrows, the density of lung markings increases, the costophrenic angle is close to a right angle or closed, the diaphragm ascends and the top flattens, and the mediastinum can shift to the affected side. When the pleura is calcified, patchy, irregular punctate, or linear hyperdense opacities at the edge of the lung field can be seen. In encapsulated pleurisy, the pleural calcification may be curvilinear or irregular.
CT
Pleural thickening is manifested by zonate opacity of soft tissue density along the chest wall, with inhomogeneous thickness and rough surface, and small adhesion can be seen at the junction with the lung; pleural thickening can be more than 1 cm, and the thickness over 2 cm is mostly suggestive of malignancy. Pleural calcification shows mostly punctate, zonate, or massive hyperdense opacities, and the CT value can be close to that of bones.
Figure 1 Pleural thickening, adhesion, and calcification
a. CT mediastinal window shows pleural adhesion and thickening on the right chest (↗); b. CT mediastinal window shows pleural adhesion, thickening, and calcification on the right chest (↗).
MRI
In visualization of pleural thickening, adhesion, and calcification, MRI is not as good as conventional x-ray and CT.