Magnetic resonance in the study of residual mediastinal masses after therapy of lymphoma

Forty-five patients with mediastinal spread of malignant, Hodgkin's and non-Hodgkin's lymphomas were examined with MR Imaging at 0.5 T. Ninety-two examinations were performed at diagnosis and/or during and after treatment to investigate MR capabilities in distinguishing fibrous tissue from active disease in the masses residuing after therapy--which cannot be done by means of CT. MR results indicated T2-weighted sequences to be the most useful. MR results were compared with the data collected from follow-up, clinics, and biology. MR Imaging had high accuracy (92.1%). The number of false negatives was very low, thanks to the low intensity of fibrous tissue, while a relatively high number of false positives was observed, probably due to the difficulties in discriminating inflammatory from neoplastic tissue.