CT demonstration of tethering of the lung by the pulmonary ligament.

An unusual form of atelectasis has been detected on CT of a patient with large pleural effusions. It has been interpreted to be the result of tethering of the lungs to the mediastinum by the pulmonary ligaments, which may have lacked normal elasticity in this case because of prior irradiation. This appearance may simulate a collection of dense material on the surface of an effusion when there is no obvious air bronchogram present.