PURPOSE:A retrospective study was performed to assess the efficacy of MRI in evaluation of therapeutic response of bone lymphoma. MATERIALS AND METHODS:We reviewed 17 cases of bone lymphoma on MRI that were follow-up studies during or after therapy. Among them, the cases with contrast study during therapy were 5, and those after therapy were 6. The four findings of follow-up MRI considered representative of improvement of bone lymphoma were the decreased size of tumor mass, the decreased signal intensity on T2-weighted images, the increased signal intensity of the tumor on T1 -weighted images, and the decreased or absent enhancement of post-contrast T1 -weighted images. RESULTS: The findings of improvement on T1 and T2-weighted images were shown in 50%(7/14) during therapy and 85.7%(12/14) after therapy. Those On post-contrast T1 -weighted images were shown in 20%(1/5) during therapy and 50%(3/6) after therapy. CONCLUSION:On MRI, both findings of the decreased signal intensity on T2-weighted images and the increased signal intensity of on T1 -weighted images of the tumor were significant in evaluating therapeutic response of bone lymphoma.