Research Goal

Key Findings

Validated alternatives to general anaesthesia for canine CT examinations exist and are well-supported by the evidence. The most prominent alternative is the use of alpha-2 agonists (medetomidine or dexmedetomidine) combined with opioids (butorphanol). This combination has been successfully applied via both intravenous and intramuscular routes to facilitate CT imaging of the spine, thorax, abdomen, and limbs. Studies consistently report that these protocols provide adequate immobilization and image quality for diagnostic purposes, with the added benefit of reducing lung atelectasis compared to general anaesthesia. Protocols involving deep sedation or "chemical restraint" using ketamine or tiletamine-zolazepam alongside alpha-2 agonists are also validated, often achieving a depth of sedation approaching anaesthesia without the need for inhalants. However, the reliability of these sedation-only protocols can vary. While many studies report successful imaging without additional drugs, one optimization study noted that while 88% of dogs could start the procedure under sedation (dexmedetomidine-ketamine-butorphanol), 57% required supplemental propofol to complete it. Furthermore, while sedation preserves lung aeration, the hemodynamic effects of alpha-2 agonists (vasoconstriction) can alter contrast enhancement timing and reduce peak perfusion in vascular studies compared to general anaesthesia. Novel approaches such as awake CT using physical restraint (e.g., cat bags, acrylic cases) are feasible for specific fast scanners or compliant patients, avoiding pharmaceutical risks entirely.