Mediastinal masses: a system for diagnosis based on computed tomography.

A revised system for mediastinal mass differentiation has been developed and used at the Veterans Administration Medical Center, San Diego, and University Hospital of the University of California, San Diego. Contrast medium infusion or bolus computed tomography of the entire mediastinum is obtained, except when the mass is probably a thyroid mass (123I scan then obtained first) or an esophageal mass (barium swallow evaluation then obtained first). Next computed tomography density is determined, and only subsequently are masses of similar density subdivided by location. Further differentiation is based on computed tomography imaging parameters. A new algorithm for evaluation of mediastinal masses has resulted from use of this system. The system has been shown to increase specificity of differential diagnosis and to result in increased efficiency of evaluation of patients with mediastinal masses.