Scimitar syndrome: four new cases examined with CT.

Four new cases of scimitar syndrome illustrate the complex derangement of the right lung architecture. Computed tomography (CT) helped in demonstrating the hyparterial relationship of the right bronchus to the pulmonary artery, the course and termination of the scimitar vein, the mediastinal shift, unusual fissures, and abnormal lobation and bronchial distribution. The CT findings confirm that the retrosternal opacity and indistinct right heart border are results of the mediastinal shift. One case had features resembling, but clearly distinguishable from, the horseshoe lung syndrome.