Comparison of18F-NaF PET/CT with Other Imaging Methods in the Detection of Bone Metastases in Patients with Medullary Thyroid Cancer: a Report of a Series of 31 Cases

Purpose To compare the(18)F-NaF PET/CT studies (F-18-NaF) with other imaging methods in the detection of skeletal metastases (SM) in patients with medullary thyroid cancer (MTC). Methods We retrospectively analyzed 31 patients with MTC who performed(18)F-NaF to assess SM. The results of the(18)F-NaF were compared with other imaging methods performed for metastasis detection:Tc-99-MDP bone scan (BS), magnetic resonance imaging (MRI), contrast-enhanced CT (CT), and(68)Ga-Dotatate and(18)F-FDG PET/CT studies. A qualitative analysis comparing the(18)F-NaF findings with the ones of the other methods was performed, and the results were classified as superior (>), equal (=), and inferior (Results Eleven patients had no bone metastases detected on any of the imaging methods used. Twenty patients presented SM depicted on(18)F-NaF. Of these 20 patients, 12 performed bone scan (in 9(18)F-NaF > BS and in 3(18)F-NaF = BS), 1 performed(18)F-FDG (F-18-NaF > F-18-FDG), 4 performed(68)Ga-Dotatate (in 2(18)F-NaF > Ga-68-Dotatate and in 2(18)F-NaF = Ga-68-Dotatate), 20 performed CT of at least one body segment (in 15(18)F-NaF = CT and in 5(18)F-NaF > CT), and 16 performed MRI of at least one body segment, and in all of them, the(18)F-NaF was equal to the MRI. Beside this, the(18)F-NaF detected SM in body segments not routinely scanned in MRI and CT. Conclusion In patients with MTC, the(18)F-NaF seems to be equal or superior to other imaging modalities in the detection of SM and allows the analysis of the whole skeletal in a single study.