FDG PET/CT imaging
Patients fasted for at least 6 h before the injection of FDG, and their blood glucose concentration was confirmed to be less than 200 mg/dL at the time of FDG injection. At 60 min after injection of 5 MBq/kg of FDG, imaging was performed using an STe PET/CT scanner (GE Healthcare) without intravenous or oral contrast. Whole-body CT images were obtained with a continuous spiral 16-slice helical CT technique (140 keV; 30–170 mA; section width, 3.75 mm). An emission PET scan was obtained from the level of the thigh to the skull base. Scanning was performed at 2.5 min per frame in 3-D mode with attenuation-corrected images (3.9 × 3.9 × 3.3 mm) reconstructed using a 3-D ordered-subset expectation maximization algorithm (20 subsets, 2 iterations).