Magnetic resonance imaging of benign mediastinal masses.

Eight patients who had benign mediastinal masses underwent CT and magnetic resonance (MR) imaging. The intensity difference between mass and surrounding mediastinal fat was greater on MR than CT images. Although the masses were clearly identified with both modalities, delineation of a mass from surrounding mediastinal structures was better with CT. Heterogeneity on CT and MR images was a prominent feature of most larger benign mediastinal masses, although this should not be considered indicative of benignity. These benign mediastinal masses were best demonstrated on MR images obtained using a long TR and short TE. In general, the MR studies provided information comparable to but not identical to that of CT scanning. The viewing of mediastinal masses using a variety of TR and TE imaging parameters appeared to be an important aspect of the MR studies.