Response of non-Hodgkin lymphoma to radiation therapy: Early and long-term assessment with H-1 MR spectroscopic imaging

PURPOSE: To determine whether proton magnetic resonance (MR) spectroscopic imaging is a sensitive technique for defining tumor extent and assessing response of cerebral lymphoma to therapy. MATERIALS AND METHODS: Four hydrogen-1 MR spectroscopic imaging studies were performed in a patient with non-Hodgkin lymphoma (NHL) before, during, and after radiation therapy and at follow-up at 33 months after diagnosis of the recurrence of disease. The patient had a single, large lesion in the brain and underwent hyperfractionated radiation therapy for 4 weeks. A series of MR images was also obtained. RESULTS: The pretreatment study showed a lesion with a distinct spectral pattern: marked elevation of choline and lipids and great reduction of creatine and N-acetylaspartate. During and after treatment, H-1 MR spectroscopic images depicted a progressive reduction of the abnormal choline and lipid signals. Thirtythree months after treatment, multiple-section H-1 MR spectroscopic images showed normal spectral patterns in all sections examined. CONCLUSION: H-1 MR spectroscopy may contribute to the neuroradiologic evaluation of NHL and, in particular, may be useful in monitoring therapeutic response.