L polamivet

Anesthesia was induced for CT and rhinoscopy by sedating the dogs with medetomidine (5 µg/kg, Domitor^®, Orion Pharma, Hamburg, Germany) administered intramuscularly and intravenous administration of diazepam (0.5 mg/kg, Rotexmedica, Trittau, Germany), levomethadone (0.25 mg/kg, L-Polamivet^®, MSD, Haar, Germany), ketamine (2 mg/kg, Ketavet^®, Pfizer Pharmacia, Berlin, Germany), and propofol dosed according to effect (1–3 mg/kg iv, Narcofol^®; CP-Pharma, Burgdorf, Germany). All animals were endotracheally intubated, and anesthesia was maintained with isoflurane (2 vol% vaporizer setting; IsoFlo^®, Essex Tierarznei, Munich, Germany) in 50 vol% oxygen under volume-controlled intermittent positive pressure ventilation. Then a maxillary nerve block (intraoral approach) with a total volume of 0.3–0.9 ml (0.5% bupivacaine (Carbostesin 0.5%^®, Aspen Germany GmbH, Munich, Germany) and 2% lidocaine (Xylocitin-loc 2%^®, Mibe GmbH, Brehna, Germany) in a 2:1 ratio) was placed depending on the animal’s size.

MRI of puppies no. 1 and 14 were performed in general anesthesia. Puppies were sedated with diazepam (0.5 mg/kg intravenously (i.v.), Diazepam lipuro, B. Braun Melsungen AG, Melsungen, Germany) and levomethadon (0.2 mg/kg i.v., L-Polamivet, MSD Animal Health GmbH, Unterschleißheim, Germany). General anesthesia was induced with propofol dosed to effect (1–3 mg/kg i.v., Narcofol, CP-Pharma, Burgdorf, Germany). Puppies were orotracheally intubated and connected to a semiclosed circle absorber system (Anaesthesia ventilator, Cato, Dräger, Langenhagen, Germany). Maintenance of anesthesia was performed with isoflurane (CP-Pharma) in an oxygen/air mixture (1:1, flow 50 ml/kg/min).
The following MRI sequences were obtained with a 3.0-T scanner (Achieva, Philips Medical Systems, Best, The Netherlands): T2w and T1w pre- and post-contrast administration (0.5 ml/kg i.v., Dotarem, medithek GmbH, Oststeinbek, Germany) each in sagittal, transversal and dorsal section as well as transversal section of FLAIR.