[Malignant lymphoma: magnetic resonance tomography findings in residual supradiaphragmatic space-occupying lesions].

PURPOSE: Evaluation of MR imaging in patients with Hodgkin's lymphoma and high grade non-Hodgkin's-lymphoma and mediastinal residual mass after first line chemotherapy.

MATERIALS AND

METHODS

MR imaging (1.5 T) was performed in 36 patients (Hodgkin's lymphoma n = 26, NHL n = 10) after first line chemotherapy). Twenty patients had inactive residual mass, 16 patients had residual lymphoproliferative lesions. T1- and T2-weighted spin echo images were visually analysed by a score index (range 1-5) as well as quantification of enhancement by signal-intensity-ratios SImax/SIplain).

RESULTS

For the differentiation between residual lymphoproliferative activity and inactive residual mass, the highest accuracy was obtained for the signal intensity of residual mass on T2-w-SE compared to pectoralis muscle (94% sensitivity, 80% specificity, likelihood ratios: 4.0 [LR+]; 0.3 [LR-]). The cut-off value of the SI ratio was calculated retrospectively at 1.96 (p > 0.05).

CONCLUSIONS

Differentiation between inactive (fibrotic) and lymphoproliferative (active) residual mediastinal mass is possible by MR imaging using as parameter the size reduction after therapy and the signal intensity on T2-w-SE in comparison to pectoralis muscle. Thus study suggests an additional value using the SI ratio for the differentiation.