(11)C-methionine PET/CT and MRI of primary central nervous system diffuse large B-cell lymphoma before and after high-dose methotrexate

Clin Nucl Med. 2012 Oct;37(10):e241-4. doi: 10.1097/RLU.0b013e318252d1ea.


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.

Publication types

  • Case Reports

MeSH terms

  • Antineoplastic Agents / pharmacology
  • Antineoplastic Agents / therapeutic use
  • Brain / diagnostic imaging*
  • Brain / drug effects
  • Dose-Response Relationship, Drug
  • Female
  • Humans
  • Lymphoma, Large B-Cell, Diffuse / diagnosis*
  • Lymphoma, Large B-Cell, Diffuse / diagnostic imaging
  • Lymphoma, Large B-Cell, Diffuse / drug therapy*
  • Magnetic Resonance Imaging*
  • Male
  • Methionine*
  • Methotrexate / pharmacology
  • Methotrexate / therapeutic use*
  • Middle Aged
  • Multimodal Imaging*
  • Positron-Emission Tomography*
  • Tomography, X-Ray Computed*
  • Treatment Outcome


  • Antineoplastic Agents
  • carbon-11 methionine
  • Methionine
  • Methotrexate