Fibrosing mediastinitis: CT and MR findings.

The aim of this study is to present the computed tomography (CT) and magnetic resonance (MR) findings in three cases of fibrosing mediastinitis, probably secondary to tuberculosis. Two patients had diffuse involvement of the mediastinum and one patient presented with a posterior mediastinal mass. On CT, the patients with diffuse involvement showed infiltrating soft-tissue masses with multiple foci of dense calcifications. One of these lesions enhanced mildly with contrast and one did not enhance. On MR examination, diffuse masses were of heterogeneous, intermediate and low signal on T1-weighted images (n = 2) and were of homogeneous low signal (n = 1) or heterogeneous (n = 1) signal intensity on T2-weighted images. After administration of Gd-DTPA, these mediastinal masses showed heterogeneous enhancement. The posterior mediastinal mass showed homogeneous pronounced enhancement on CT and was homogeneous with intermediate T1 signal intensity and hypointense T2 signal intensity. The CT findings of an infiltrative or well-defined mediastinal mass with scattered calcifications should suggest the diagnosis of fibrosing mediastinitis in the appropriate clinical setting. Although the appearance of calcification on MR are not specific, this technique provides further information than CT especially in those cases in which the lesions appear noncalcified, because MR imaging revealed areas of low signal intensity characteristic of fibrous tissue.