Computed tomography was employed in 71 patients to assess a widened mediastinum detected on plain chest radiographs. In 92% of the patients, CT correctly identified normal variants, soft-tissue density masses or vascular abnormalities as the cause of mediastinal widening. In 8% of the scans, all performed early in our experience, CT diagnosis was indeterminate (4%) or incorrect (4%). In 58% of the cases, a specific and correct CT diagnosis was made, which obviated further and more invasive diagnostic evaluation. CT scanning can differentiate vascular from avascular causes of mediastinal widening, and provide a specific and conclusive diagnosis in many instances. Invasive diagnostic procedures should be reserved for the few cases in which CT is indeterminate or additional preoperative information is required.
