PET in myeloma redefined: a comparative imaging study with FDG and fluorocholine PET/CT

Multiple myeloma (MM) frequently evades complete evaluation with 18 F-FDG-PET/CT due to variable hexokinase expression, leading to false-negative findings. 18 F-fluorocholine-PET/CT (FCH) targets membrane phospholipid synthesis and has been proposed as an alternative imaging strategy to address this limitation.

In this single-center retrospective study, 35 adult MM patients underwent dual-tracer PET/CT within four weeks. Lesions were scored using Deauville-based criteria (IMPeTUs), and exploratory composite scores (hTepe and myPET) were calculated. Laboratory markers, including M-protein, free light chains, and bone marrow infiltration, were collected within four weeks of imaging.

The cohort (22 men, 13 women; mean age 62.2 ± 10.9 years) included 19 patients at initial staging and 16 at restaging. FDG detected active disease in 49% of patients, with 50.0% sensitivity and 100% positive predictive value (PPV). FCH identified disease in 91%, achieving 94.1% sensitivity and 100% PPV. Median bone marrow Deauville scores were similar (score-3), but FCH demonstrated significantly higher hypermetabolic focus scores (median 4 vs. 1; p < 0.001). FCH uptake moderately correlated with marrow plasma cell infiltration and inversely with hemoglobin and albumin, whereas FDG showed no consistent biochemical associations.

FCH demonstrates superior diagnostic performance compared to FDG in MM, particularly in red marrow-rich regions. FCH more reliably reflects disease burden and aligns more closely with laboratory markers, supporting its role in staging, residual disease assessment, and treatment monitoring. Collectively, these results highlight FCH as a clinically applicable biomarker of disease burden with potential utility in routine staging and response evaluation in multiple myeloma.