Role of 18F-FDG PET/CT in staging of patients with multiple myeloma

Objectives Multiple myeloma(MM) is the most common plasma cell neoplasm, with abnormal clone proliferation of B cells in bone marrow. The aim of this study was to investigate the characteristics of PET/CT imaging and to assess the value of 18F-FDG PET/CT in staging of patients with MM.

Methods 32 newly diagnosed MM patients underwent 18F-fluomdeoxyglucose (FDG) PET/CT imaging before treatment. All patients received 370-555 MBq of 18F-FDG intravenously, and whole body PET/CT scans were acquired 60 min after injection using Siemens Biograph 64 PET/CT scanner. Histopathology was confirmed by bone marrow biopsy. Serum IgG and urine Bence-Jones protein were measured. The number and site of lesions detected by 18F-FDG PET/CT were compared with those of CT and/or MRI.

Results One of 32 patients has normal 18F-FDG PET/CT imaging. The other 31 patients have abnormal FDG uptake with three main patterns: focal(n=7) ,diffuse(n=5) , focal and diffuse(n=19). A total 242 lesions were detected on PET/CT imaging. 175 lesions was hypermetabolic uptake, whereas other 67 lesions with hypometabolic uptake. On CT imaging, typical findings were multiple osteolytic lesions and punched-out defected without surrounding sclerosis. 18F-FDG PET/CT detected more osteolytic lesions than MRI in 10/31 pts (32%). MRI was superior to18F-FDG PET/CT in the assessment of bone marrow involvement of the spine in MM patients with diffuse FDG uptake.

Conclusions 18F-FDG PET/CT is useful in the detection of osseous and extramedullary involvement. Combined whole body 18F-FDG PET/CT and MRI of the spine is recommended in staging of MM patients