Radiosynthesis and PET Imaging of [18F]FEPPA

[¹⁸F]FEPPA radiosynthesis and control quality were performed as previously described [19 (link)]. [¹⁸F]FEPPA radiochemical purity was more than 99% and its molar activity at the end of synthesis was 183 ± 80 GBq/µmol. During radiotracer administration and image acquisition, mice were anesthetized with 2.5% and 1–1.5% isoflurane in oxygen at 0.8–1.5 L/min and 0.4–0.8 L/min respectively for induction and maintenance. PET/CT studies investigating brain inflammation were performed after the injection of [¹⁸F]FEPPA diluted in 150 µL saline (10 MBq) into the lateral tail vein of mice. The injection was made on an Inveon micro PET/CT animal scanner (Siemens Medical Solutions^®, Saint-Denis, France) with a spatial resolution of 1.4 mm full width at half-maximum at the center of the field of view. Dynamic mod-list PET acquisitions of the whole-body mice were performed from the time of the radiotracer injection until 60 min after the injection (n = 12 FL and 12 KO Cx43) and followed by a 3-min duration CT acquisition. PET data were reconstructed using 3-dimensional ordered-subset expectations maximization algorithm into a 128 × 128 image matrix (21 frames: 3 × 5, 3 × 15, 4 × 30, 3 × 60, 2 × 120, 4 × 300, 2 × 900 s and were corrected for random, scatter and decay events.