Cerebral Metabolism in Dogs Assessed by 18F-FDG PET: A Pilot Study to Understand Physiological Changes in Behavioral Disorders in Dogs

The positron emission tomography (PET) imaging technique, which is utilized in human behavior and psychiatric disorder research, was performed on the brains of clinically normal mixed breed dogs, 3 hound-type (long floppy ears) mixed breed dogs and 3 non-hound retriever-type mixed breed dogs. Glucose metabolism was obtained with F-18 fluorodeoxyglucose (FDG), and quantitative analysis was performed by standardized uptake value (SUV) measurement. Magnetic resonance (MR) images were obtained in each dog, and these images were superimposed on PET images to identify anatomical locations. The glucose metabolism in each region of interest was compared between the three hound-type dogs and 3 non-hound-type dogs. The two anatomically different types of dog were compared to assess whether breed-typical behavioral tendencies (e.g., sniffing behavior in hound-type dogs, staring and retrieving in Labrador-type dogs) are reflected in baseline brain metabolic activity. There were no significant differences between the hound-type dogs and non-hound-type dogs in cerebral SUV values. These data might serve as normal canine cerebral metabolism data for FDG PET studies in dogs and form the basis for investigations into behavioral disorders in dogs such as compulsive disorder, anxiety disorders and cognitive dysfunction.