Comparison of Bone Metastases between (18)F-NaF PET/CT, (18)F-NaF PET, and Planar (99m)Tc-MDP Bone Scintigraphy in Patients with Newly Diagnosed Nasopharyngeal Carcinoma

PURPOSE: Our study aims to compare the diagnostic value of (18)F-NaF positron emission tomography-computed tomography (PET/CT), (18)F-NaF PET, and planar (99m)Tc-MDP bone scintigraphy for detection of bone metastases in patients with newly diagnosed nasopharyngeal carcinoma (NPC). METHODS: Our study retrospectively analyzed 58 patients with pathologically proven NPC. They all underwent both (18)F-NaF PET/CT and planar (99m)Tc-MDP bone scintigraphy within a 7-day interval. Bone metastases were confirmed by follow-up using PET/CT, contrast-enhanced computed tomography (CT), and magnetic resonance imaging (MRI). These three examinations were compared using per-patient-based analysis and per-lesion-based analysis. RESULTS: 19 patients (32.7%) were classified as having bone metastatic disease in their final diagnosis. The patient-based diagnostic performances (sensitivity, specificity, and overall accuracy) were as follows: (18)F-NaF PET/CT (100%, 92.3%, and 94.8%), (18)F-NaF PET (100%, 53.8%, and 69.0%), and planar (99m)Tc-MDP bone scintigraphy (78.9%, 74.4%, and 75.9%). The overall accuracy of (18)F-NaF PET/CT was significantly more favorable compared to (18)F-NaF PET (p=0.002) and to planar (99m)Tc-MDP bone scintigraphy (p=0.044). The lesion-based diagnostic performances (sensitivity, specificity, and overall accuracy) were as follows: (18)F-NaF PET/CT (98.5%, 93.9%, and 96.6%), (18)F-NaF PET (98.5%, 57.1%, and 81.1%), and planar (99m)Tc-MDP bone scintigraphy (69.9%, 85.7%, and 76.4%). CONCLUSION: (18)F-NaF PET/CT outperforms (18)F-NaF PET or planar (99m)Tc-MDP bone scintigraphy in detecting bone metastases with newly diagnosed NPC on a patient-based and lesion-based analysis.