Journal of Blood & Lymph

Can 18F-FDG PET/MR Imaging Contribute to the Assessment of Bone Lesions in Patients with Plasma Cell Dyscrasias?

Abstract

Rajnics P, Tóth Z, Zádori P, Repa I, Kovács A, Moizs M and Egyed M

Objective: Two patient groups were studied for evaluation of detection efficacy of 18F-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging (18F-FDG PET/MRI). The first group was dedicated to assess the possible early bone lesions of those patients who had been diagnosed with monoclonal gammopathy of undetermined significance/smouldering multiple myeloma (MGUS/SMM). In the second group, the detection sensitivity of the PET/CT and PET/MRI for bone lesions was compared to each other in patients with symptomatic plasmacytic myeloma (PCM).
Methods: 14 patients with MGUS/SMM and 27 patients with PCM were enrolled in this study. Initially, all patients underwent an 18F-FDG PET/CT examination and it was followed by a PET/MRI imaging.
Results: No bone lesion was detected with PET/CT and PET/MRI in patients either with MGUS and SMM. Bone marrow alteration was also not detected with PET/MRI in this group. Disease progression has not been revealed in the course of the 18 months follow-up period. In regard to lesion detection, there was no difference between the PET/CT and PET/MRI in the symptomatic PCM group. The metabolic tumor volume (MTV) was found to be strongly correlating with both the β2-microglobulin serum level and the ISS stage.
Conclusion: PET/MRI is a reliable diagnostic tool for detection of bone lesions in plasma cell discrasias, and it is not inferior to the PET/CT imaging. The MTV measurement can provide a promising diagnostic tool for the direct assessment of myeloma tumor loading in the future.