Diagnostic utility of FDG PET in multiple myeloma.
OBJECTIVE
Very little information is available regarding the diagnostic utility of positron emission tomography with [(18)F]fluorodeoxyglucose (FDG PET) in multiple myeloma. Our objective was to further define the role of FDG PET in the clinical assessment of patients with multiple myeloma.


METHODS
Nine whole-body PET scans (45 min after intravenous administration of 370-555 MBq FDG) were performed in six patients (age 38-62 years, 5 males) with multiple myeloma for evaluation of the extent of disease at the time of initial diagnosis (n=3) and for assessment of therapy response (n=3). Three patients had PET scans both before and after therapy. Prior treatments included chemoradiation therapy (n=2) and chemotherapy with autologous bone marrow transplantation (n=1). Correlative imaging data were available in all patients and included skeletal radiographic survey (n=6), bone scan (n=3), and spinal CT or MRI (n=4), and were all obtained within 3 months of the PET study. Validation was by clinical or imaging follow-up.


RESULTS
In three patients with both pre- and post-therapy PET scans, PET demonstrated a favorable treatment response, by showing a decline in lesion metabolic activity (n=1), or progression of disease, by showing development of new lesions or higher lesion glucose metabolism (n=2), concordant with the clinical evaluation, while the other imaging studies showed no discernible interval changes. PET detected multiple hypermetabolic lesions in one patient with a negative bone scan and concordant positive skeletal radiographic survey. Bone scans underestimated the extent of disease in two other patients in comparison with PET. PET also detected a few early marrow lesions with subtle radiographic changes while all radiographically aggressive lytic lesions corresponded to intense hypermetabolism on PET.


CONCLUSIONS
PET can detect early marrow involvement of multiple myeloma and is useful in assessing the extent of active disease at the time of initial presentation and in evaluating treatment response.
Jadvar
Hossein
H
PET Imaging Science Center, Division of Nuclear Medicine, Department of Radiology, Keck School of Medicine, University of Southern California, 1200 N. State Street, GNH 5250, Los Angeles, CA 90033, USA. jadvar@usc.edu
Conti
Peter S
PS
D000328:Adult; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000000981:diagnostic imaging*; D019275:Radiopharmaceuticals; D014055:Tomography, Emission-Computed
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18