Skip Navigation LinksHome > October 2012 - Volume 37 - Issue 10 > 11C-Methionine PET/CT and MRI of Primary Central Nervous Sys...
Clinical Nuclear Medicine:
doi: 10.1097/RLU.0b013e318252d1ea
Original Articles

11C-Methionine PET/CT and MRI of Primary Central Nervous System Diffuse Large B-cell Lymphoma Before and After High-Dose Methotrexate

Jang, Su Jin MD*; Lee, Kyung-Han MD; Lee, Ji Young MD*; Choi, Joon Young MD; Kim, Byung-Tae MD; Kim, Seok Jin MD; Kim, Won Seog MD

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Abstract

Purpose: Although the optimum treatment of primary central nervous system lymphoma (PCNSL) remains a challenge, there is increasing interest in methotrexate-based chemotherapy as an effective strategy. Here, we report evidence supporting the utility of methionine PET/CT for evaluating PCNSL disease extent and response to high-dose methotrexate therapy.

Patients and Methods: Four patients newly diagnosed with diffuse large B-cell PCNSL underwent methionine PET/CT and MRI of the brain at baseline and again after completion of high-dose methotrexate combination chemotherapy. Three patients also received pretreatment FDG PET/CT, and the intervals between MRI and both PET/CTs were within 3 weeks. The results of methionine PET/CT were compared with MRI and clinical findings.

Results: Pretreatment methionine PET/CT demonstrated clear demarcation of PCNSL tumors with high contrast in 3 patients and only faint uptake in the remaining patient, which also showed low FDG uptake. In 1 patient, methionine PET/CT displayed more tumor lesions than FDG PET/CT did. After high-dose methotrexate chemotherapy, methionine images displayed complete disappearance of abnormal uptake in all 4 patients. In 3 of the patients, posttreatment MRI and clinical follow-up corroborated findings of complete remission. In the remaining patient, MRI showed nonenhancing T2 hyperintensities in the periventricular white matter, for which the significance was inconclusive.

Conclusions: Methionine PET/CT may provide clinically useful information complementary to MRI for monitoring the response to systemic chemotherapy in patients with PCNSL.

© 2012 Lippincott Williams & Wilkins, Inc.

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