Regional Cerebral Blood Flow Changes in Dogs with Anxiety Disorders, Measured with SPECT

Alterations of regional brain activity in the prefrontal cortex and in limbic areas have been reported in humans with anxiety disorders. This animal study reports the results of brain perfusion imaging with single photon emission computed tomography (SPECT) in dogs with anxiety disorders. Based on the human literature, we hypothesized altered prefrontal and higher temporal brain perfusion. SPECT acquisitions were performed using the Tc-99m-labelled tracer ethyl cysteinate dimer (ECD). Eighteen dogs with pathological anxiety were compared with 18 normally behaving reference dogs. We found, in the group of dogs with anxiety disorders, lower perfusion in the left frontal cortex (p = 0.003), in the subcortical region (p = 0.007) and increased perfusion in the right (p = 0.05) temporal cortex. Taken together, our rCBF findings are suggestive for a dysfunction of the prefrontal cortex and the limbic system in canine anxiety disorders.