Mri compatible cradle

Magnetic resonance imaging was performed on day 60 post-surgery. Anesthesia was induced using isoflurane (4% induction, 1–2% during preparation, and 0–0.3% during concurrent medetomidine infusion) in 40:60 O₂ in medical air (2 L/min flow rate). The rats anesthetized were positioned on an MRI-compatible cradle (Bruker Biospin, Germany) with ear and tooth bars in place to reduce head motion. Rectal temperature and respiratory pattern and rates were monitored using a MR-compatible monitoring and gating system for small animals (Model 1030, Small Animal Instruments, New York, USA). After positioning the animal inside the MRI scanner, we administered the α₂-agonist medetomidine through a peritoneal catheter as a bolus (0.05 mg/kg), immediately followed by continuous infusion (0.1 mg/kg/h). Respiration rate was in the range of 60–95 breaths per minute. Rectal temperature was maintained at 36 ± 1°C by thermostatically controlled warm water circulating in tubes embedded in the animal holding cradle (SC100, Thermo Scientific, USA).

Anaesthesia was induced using 3% isoflurane in 60% air, 40% O₂ at 1L/min. The isoflurane concentration was maintained at 2–2.5% during the preparation which took around 30 min. Each mouse was positioned on an MRI-compatible cradle (Bruker Biospin, Germany) with ear bars and bite bars to reduce head motion. A peritoneal catheter was inserted and fixed to the mouse for delivery of medetomidine (Domitor, Pfizer, USA). For sedation, a bolus of 0.05 mg/kg medetomidine was given intraperitoneally and then sedation was maintained with a continuous infusion of 0.1 mg/kg/h. Once the animal was inside the MRI scanner, isoflurane was then reduced gradually and kept at approximately 0.25% throughout the experiment. The total time under anaesthesia for each animal was approximately 2.5 h. At the end of the scanning session, 1.25 mg/kg atipemazole (medetomidine reversal) (Antisedan, Pfizer, USA) was given intraperitoneally.