Magnetic resonance imaging of intrathoracic masses

65 patients suspected of having intrathoracic masses were studied using magnetic resonance imaging (MRI) and computed tomography (CT). The intensity difference between mass and adjacent normal tissue or mediastinal fat was greater on MRI than on CT images. MRI was superior to CT in differentiating bronchogenic carcinomatous tumours from postobstructive pneumonia and/or lobar collapse. MRI images most clearly depicted obstructed mediastinal vessels and were also able to indicate intravenous flow reductions. The latter could be demonstrated by an increase of signal intensity within venous structures proximal to the obstruction. In patients with lung cancer no significant differences were found between the two imaging methods for the evaluation of tumour extent or node involvement. (orig.)