PET-CT Imaging of Ketamine Effects

In a separate experiment, animals were randomly assigned into three groups: saline control (n = 11), 10 mg/kg (n = 9), or 20 mg/kg (n = 12) ketamine. Two ¹⁸F-FDG-PET and computed tomography (CT) scans were obtained for each animal at baseline, 4 to 5 days before the experiment (scan 1) and immediately after fear conditioning and ketamine infusion (scan 2). ¹⁸F-FDG-PET and CT images were acquired using an Inveon multimodality preclinical scanner (Siemens Medical Solutions, Erlangen, Germany) in the small animal imaging facility at USU as described previously [13 (link)]. Animals were briefly anesthetized with isoflurane (4% induction and 1.5–2.5% maintenance) and injected with 1.7 ± 0.153 mCi (62.9 ± 5.7 MBq) ¹⁸F-FDG through the tail vein. After ¹⁸F-FDG injection, the animal was returned to a clean cage during the uptake period (30 min) in a quiet room adjacent to the PET and CT scanner. Animals were undisturbed and exhibited minimal movement in their cages during the ¹⁸F-FDG uptake period. After uptake, animals were anesthetized with isoflurane (4% induction and 1.5 to 2.5% maintenance) to perform PET and CT scans. Physiologic monitoring during the scan included measurements of temperature, respiration rate, heart rate, and oxygen saturation.