Investigating cerebral blood flow in anxious dogs: a 99mTc-HMPAO SPECT imaging study

Anxiety-related disorders have a significant effect on the welfare of pet dogs, often leading to behavioral problems and straining the human-animal bond. Conventional treatments sometimes prove inadequate, highlighting the need for a more objective understanding of the neurobiological pathways underlying canine anxiety disorders. Therefore, this study aimed to investigate anxiety disorders in dogs using 99mTc-HMPAO single photon emission computed tomography (SPECT), focusing on the left frontal region, subcortical region, and cerebellum. While a frequentist approach found no significant differences in brain perfusion between patient and healthy dogs, Bayesian analyses indicated underpowered results. Subsequent correlational analyses were performed and revealed significant positive associations between cerebellar perfusion and aggression, social fear, and nonsocial fear C-BARQ cluster scores (Canine Behavioral Assessment and Research Questionnaire), as well as a negative correlation between subcortical perfusion and nonsocial fear C-BARQ cluster scores in dogs with an anxiety disorder. This study supports the involvement of subcortical regions in anxious dogs and emphasizes the emerging role of the cerebellum in canine anxiety disorders. This study deepens our understanding of the neural correlates of canine anxiety and underscores the potential of nuclear neuroimaging in clinical practice. Future research into broader neural functioning is warranted for improved diagnostic and therapeutic strategies in veterinary behavioral medicine.