LAUSR

PURPOSE PET/CT with both C-choline and C-methionine has recently been reported to offer advantages over F-FDG for imaging in multiple myeloma (MM). The aim of this study was to directly compare the diagnostic performance of both non-FDG radiotracers in MM patients. METHODS Nineteen patients with a history of MM (n = 18) or solitary bone plasmacytoma (n = 1) underwent both C-choline and C-methionine PET/CT for diagnostic imaging. In this retrospective analysis, scans were compared on a patient and on a lesion basis. In 12 patients, respective tracer uptake in the iliac crest was correlated with the extent of malignant bone marrow plasma cell infiltration. RESULTS C-methionine detected more intramedullary MM lesions in 8 (42.1%) of 19 patients. In the remainder (11/19 [57.9%]), both C-choline and C-methionine provided equal results. C-methionine demonstrated higher lesion-to-muscle ratios (P = 0.0001). In the 12 patients in whom a recent bone marrow biopsy was available, SUVmean as well as SUVmax correlated significantly with the degree of malignant plasma cell infiltration for both C-methionine (SUVmean: r = 0.85, P < 0.001; SUVmax: r = 0.82, P = 0.001) and C-choline (SUVmean: r = 0.72, P < 0.008; SUVmax: r = 0.73; P = 0.006). CONCLUSIONS Our data suggest that C-methionine PET/CT might be more sensitive than C-choline PET/CT for the detection of active MM lesions.