Prospective evaluation of diagnostic performance to detect bone metastasis with F-18 NaF PET/CT and Tc-99m MDP bone scintigraphy

Objectives The aim of the present study was to compare diagnostic performance of bone metastasis prospectively with F-18 NaF PET-CT and Tc-99m MDP bone scintigraphy (BS).

Methods A total of 190 lesions in 24 patients (mean age, 63 years) with bone metastases who underwent both of whole-body F-18 NaF PET/CT and BS were assessed in this study. We investigated the detectability of bone metastasis with regard to histologic subtypes of primary tumors, morphologic patterns based on CT findings, and distribution on the lesion-basis. Images were assessed independently by 2 readers without knowledge of patient background. All lesions were interpreted according to three diagnostic categories: normal or benign, equivocal, and suspect of malignant.

Results The sensitivity and specificity by categorizing equivocal lesions into benign were 99% and 100% in F-18 NaF PET/CT, 77% and 60% in F-18 NaF PET alone, and 63% and 47% in BS. Detectability of bone metastasis did not depend on modality in prostate (n=73) and breast carcinoma (n=79). However, accuracy in F-18 NaF PET/CT or BS was greater than those of BS in malignant tumors except for prostate and breast carcinomas. Diagnostic accuracy of osteoblastic lesion (n=111) was superior in each modality to those of osteolytic (n=29) or mixed-type lesion (n=36).

Conclusions Diagnostic performance of F-18 NaF PET/CT to detect bone metastasis is superior to BS. Detectability of bone metastasis is significant when stratified by osteoblastic morphologic pattern in this prospective analysis.