Bone metastasis in malignancy: the diagnostic role of 18F-FDG PET/CT

Objective: The aim of this retrospective study was to understand the role of18F-fluorodeoxyglucose (FDG) PET/CT in detecting bone metastasis in various cancers. Methods: Six hundred and eighty-nine cancer patients who had 18 F-FDG PET/CT were included. The diagnosis of bone metastasis was based on matched findings of FDG-avid lesion on PET and characteristic morphological changes on CT. The sensitivity, specificity and accuracy of CT, and PET/CT were calculated and the results were statistically analyzed (McNemar test). Results: Ninety-one patients with 442 regions were diagnosed to have bone metastases. On patient base analysis, the sensitivity, specificity, and accuracy of hybrid CT for detecting bone metastases were 79.1% (72/91) , 91.8 % ( 549/598 ) , 90.1% ( 621/689 ) and were 94.5% (86/91), 97.8% (585/598), 97.4% (671/689) for PET/CT (χ2=20.049, 148.890, 168.792, all P=0.000). On lesion base analysis, the sensitivity, specificity, and accuracy of hybrid CT for detecting bone metastases were 81.0% (358/442), 90.4% (423/468), 85.8% (781/910) and were 95.0% (420/442), 97.2% (455/468), 96.2% (875/910) for PET/CT (χ2=98.673, 125.691, 220.375, all P= 0.000). The maximum standardized uptake value ( SUVmax) of PET true positive and false positive lesions were 6.7 ± 3.0 and 3.7 ± 1.3 respectively (χ2 =463.120, P =0.000). The SUVmax of osteoblastic and osteolytic lesions were 4.9 ± 2.0 and 7.4 ± 3.1, respectively (χ2 =327. 175, P=0.000). Conclusions: It is worth noting that 18F-FDG PET/CT is a novel tool to evaluate bone metastasis and its performances due to the combination of PET and CT. Hybrid CT has a high value in providing precise location of the metastatic sites. (authors)