The value of FDG PET/CT in the initial staging and bone marrow involvement of patients with multiple myeloma.

OBJECTIVE: The aim of this study was to describe the role of positron emission tomography/computed tomography (PET/CT) with fluorine-18 fluorodeoxyglucose (FDG) in the detection of skeletal and visceral involvement in patients with MM (multiple myeloma) at the initial diagnosis and to evaluate the relation between maximum standardized uptake values (SUVmax) of FDG with bone marrow cellularity and plasma cell ratios.

MATERIALS AND METHODS: The study population consisted of 42 patients (15 F, 28 M; mean ± SD age; 47 ± 12 years). Thirty-two patients were referred for initial diagnosis and ten patients were referred for assessment of therapy response. PET/CT scan was obtained 60 min after the administration of 5.4 MBq/kg FDG. The SUVmax of FDG uptake was measured from the region of interest, which was placed at the site of most prominent lesion in bone marrow in PET/CT images.

RESULTS: Thirty patients were positive (29 of 32 initially diagnosed, one of ten previously treated) and 12 patients were negative on PET/CT scan. Conventional radiological methods were negative in three of 30 FDG PET/CT-positive patients and these methods did not show any pathological finding in 12 FDG PET/CT-negative patients. The sensitivity of FDG PET in detecting bone marrow involvement at initial diagnosis was 90%. There was a significant correlation between SUVmax values and bone marrow biopsy cellularity and plasma cell ratios, (r = 0.54 and r = 0.74, p < 0.01).

CONCLUSIONS: The results of this study demonstrated that FDG-PET is a useful technique for the assessment of MM and the correlation between SUVmax and plasma cell ratios in bone marrow biopsy may avoid repeated bone marrow biopsies in the follow-up period.