When the brain is active, such as during thinking or speaking, it consumes glucose. Dynamic [18F]-FDG PET imaging is a technique that specifies when and where glucose is being consumed. This reveals patterns of activity between regions over time and how they are connected based on glucose consumption, also known as metabolic connectivity. In this study test-retest reliability of dynamic [18F]-FDG PET was evaluated in rats’ brains to see how consistently glucose metabolism is measured between two time points. Obtaining identical dynamic PET scans in the same animal a few days later is nearly impossible. This is because certain factors such as random background noise and limited spatial resolution of the scanner are always present and can affect the results. These technical limitations mean that no scan is truly “perfect” and some variation is expected each time. If scans are reliable, they can be used to diagnose diseases earlier, but also to monitor whether treatments are working. This work is valuable for multiple sectors, including healthcare and research. If preclinical findings can be translated into human use, it may lead to better tools for patients in a more accurate and personal way. For researchers, it promotes standardization for brain imaging methods, both in animal and clinical studies. Improved brain scans lead to better decisions for doctors, researchers and most importantly for patients. By improving how we measure brain metabolism, this research may support more personalized care, earlier diagnoses and potentially better outcomes for people living with brain disorders.