Biograph mct 16

Radiosynthesis and preparation of ¹⁸F-THK-5351 PET tracers were performed as described previously (17 (link)). Tau PET images were acquired 50–60 min after intravenous injections of 378 ± 17 MBq of ¹⁸F-THK-5351 on a dedicated PET/CT scanner (Siemens Biograph mCT 16; Siemens Medical Solutions). The same reconstruction protocols were applied as with the amyloid PET images. In addition, all subjects received an MRI scan with a 3T MR scanner (Magneton Trio, a TIM system, Siemens, Erlangen, Germany) to screen for other diseases and obtain structural information.

The ¹⁸F-THK-5351 radiotracer was synthesized with a slight modification of the method by Harada et al. (details in Additional file 1) [3 (link), 10 (link)]. Serial ¹⁸F-THK-5351 PET scans of the whole brain were acquired on a dedicated PET/CT scanner (Siemens Biograph mCT 16; Siemens Medical Solutions). Ten 1-min frames of PET images were acquired 50–60 min after an intravenous injection of 378 ± 17 MBq ¹⁸F-THK-5351 (¹⁸F-THK-5351 images) [11 (link)]. PET images were reconstructed using a three-dimensional OSEM (ordered subset expectation-maximization) algorithm (four iterations, 24 subsets; Gaussian filter = 2 mm; zoom = 3) with low-dose CT-based attenuation and scatter and random correction. The intervals from the index stroke to the ¹⁸F-THK-5351 PET study were recorded in days.