Pleural calcification. Coloured frontal X-ray of the lungs of a patient with pleural calcification. The calcifications are seen as the white areas in the lower parts of the dark spaces that are the two lungs (left and right). The structures down centre separate the two lungs; the diaphragm is across bottom; the collar bones are across top, and the ribs enclose the lungs. Pleural calcification is a thickening and calcification of the pleural membranes that surround the lungs. It usually occurs secondary to an infection such as pneumonia or tuberculosis. Further calcification can be prevented by treating the underlying cause.