The basic radiographic manifestations of pneumoconiosis can be categorized into four types: small opacities, including rounded small opacities, irregular small opacities, large opacities, small opacity clusters, and pleural plaques. 1. Rounded small opacities refer to nodular shadows with a diameter of less than 10 millimeters, which are the most common and significant imaging findings in pneumoconiosis, particularly in silicosis. 2. Irregular small opacities refer to reticular or honeycomb-like shadows with a width of less than 10 millimeters, which are the primary imaging findings in asbestosis, atypical silicosis, and other forms of pneumoconiosis. 3. Large opacities refer to shadows with a diameter or width greater than 10 millimeters, often accompanied by emphysema, and typically appear symmetrically in the upper and middle lung zones. 4. Small opacity clusters refer to localized areas where small opacities are significantly increased and clustered but have not yet formed large opacities. 5. Pleural plaques refer to localized pleural thickening or calcified pleural plaques with a thickness greater than 5 millimeters, excluding the apical and costophrenic angle regions, and are commonly seen in asbestosis.