Computed tomography of the thorax and standard radiographic evaluation of the chest: a comparative study.

Comparison of standard radiographic evaluation of the chest with computed tomography (CT) was carried out in 109 patients who were examined on a prototype EMI CT5000 scanner. Forty-eight patients had lung problems, and 61 were evaluated because of a mediastinal mass or widening, or for the detection of an occult thymoma in myasthenia gravis. Computed tomography was of value in the staging of bronchogenic carcinoma, particularly in the detection of direct mediastinal and pleural extension, and in evaluating patients with solitary or multiple nodules by detecting additional lesions and calcification. Thymomas not detected on conventional imaging modalities were visualized in 4 of 33 patients with myasthenia gravis or red cell aplasia. One of these was a false positive. In 28 patients with a mediastinal mass or widening on the chest roentgenogram, incremental information was noted on CT in 22. These included a definitive diagnosis of lesions composed of fat, evaluation of the isolated esophagus after colon by bypass surgery,and identification of the cause of paraspinal widening.