FDG PET/MR for the assessment of lymph node involvement in lymphoma: initial results and role of diffusion-weighted MR

Abstract

Rationale and objectives: The purpose of this study was to evaluate the sensitivity and specificity of positron emission tomography/magnetic resonance imaging (PET/MR) with 18F-fluorodeoxyglucose (FDG) for nodal involvement in malignant lymphoma.

Materials and methods: Twenty-seven patients with malignant lymphoma (16 men and 11 women; mean age, 45 years) were included in this retrospective study. The patients underwent FDG PET/MR after intravenous injection of FDG (176-357 MBq FDG, 282 MBq on average). Follow-up imaging and histology served as the standard of reference.

Results: One-hundred and twenty-seven (18.1%) of 702 lymph node stations were rated as having lymphoma involvement based on the standard of reference. One-hundred and twenty-four (17.7%) of 702 lymph node stations were rated as positive by FDG PET/MR. The sensitivity and specificity of FDG PET/MR for lymph node station involvement were 93.8% and 99.4%.

Conclusions: FDG PET/MR is feasible for lymphoma staging and has a high sensitivity and specificity for nodal involvement in lymphoma. Comparison with PET/CT is necessary to determine whether FDG PET/MR can replace PET/CT for lymphoma staging.

Keywords: Lymphoma; PET/MR; sensitivity; specificity; staging.