Comparison between 18F-NaF PET and PET-CT to detect bone metastases in patients with lung cancer

Abstract

Objective To evaluate the effect of 18F-sodium fluoride(18F-NaF)PET-CT in the detection of bone metastases in patients with lung cancer.Methods Thirty-four patients with newly diagnosed lung cancer were performed with 18F-NaF PET-CT.18F-NaF PET and 18F-NaF PET-CT were interpreted separately.Lesions were categorized as malignant,benign or inconclusive.A panel of reference methods was used,including MRI(34 patients),18F-fluorodeoxyglucose PET-CT(4 patients),histopathology(2 patients),or clinical follow-up of at least 6 months(6 patients).Results In patient-based analysis,11 of 34 patients had bone metastases.18F-NaF PET-CT correctly diagnosed all 11 patients with bone metastases,18F-NaF PET only correctly detected 8 of them.18F-NaF PET-CT had no false and inconclusive diagnosis.In lesion-based analysis,118 lesions were assessed which had final diagnosis(47 metastases,71 benign lesions).18F-NaF PET-CT was correct in 46 metastatic lesions and 71 benign lesions,but false-negative in lesion.18F-NaF PET was correct in 27 metastatic lesions and 64 benign lesions,but wrong in 3 lesions(2 benign lesions,1 metastatic lesions),and equivocal in 24 lesions.Based on the corresponding appearance on low-dose CT,46 of 47 lesions were categorized metastases(31 presented as sites of increased uptake with corresponding lytic or sclerotic changes,and other 15 metastases show normal or non-specific appearing bone),only 1 sclerotic metastasis was judged benign. All 71 benign lesions have a benign appearance on low-dose CT. In patient-based analysis, categorizing equivocal and malignant interpretation as suggestive for malignancy, the 18F-NaF PET-CT was more specific than 18F-NaF PET(100% vs 78%, χ2=10.78, P 0.05). In lesion-based analysis, the similar results were obtained as patient-based analysis.Conclusion 18F-NaF PET-CT was both sensitive and specific for detection of bone metastases in patients with newly diagnosed lung cancer. With the diagnosis information of low-dose CT, its ability of differentiation between malignant and benign lesions is improved. Key words: Lung neoplasm; Neoplasm metastasis; Positron-emission tomography; Tomography, X-ray computed; Sodium fluoride F18