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

Abstract

Purpose. Our study aims to compare the diagnostic value of 18F-NaF positron emission tomography-computed tomography (PET/CT), 18F-NaF PET, and planar 99mTc-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 18F-NaF PET/CT and planar 99mTc-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: 18F-NaF PET/CT (100%, 92.3%, and 94.8%), 18F-NaF PET (100%, 53.8%, and 69.0%), and planar 99mTc-MDP bone scintigraphy (78.9%, 74.4%, and 75.9%). The overall accuracy of 18F-NaF PET/CT was significantly more favorable compared to 18F-NaF PET ( $p=0.002$ ) and to planar 99mTc-MDP bone scintigraphy ( $p=0.044$ ). The lesion-based diagnostic performances (sensitivity, specificity, and overall accuracy) were as follows: 18F-NaF PET/CT (98.5%, 93.9%, and 96.6%), 18F-NaF PET (98.5%, 57.1%, and 81.1%), and planar 99mTc-MDP bone scintigraphy (69.9%, 85.7%, and 76.4%). Conclusion. 18F-NaF PET/CT outperforms 18F-NaF PET or planar 99mTc-MDP bone scintigraphy in detecting bone metastases with newly diagnosed NPC on a patient-based and lesion-based analysis.