Why clinicians should know if patients are on the keto diet before undergoing PET imaging
Can a ketogenic diet affect patients’ imaging results? When it comes to PET scans of the brain, the answer is yes [1].
Researchers recently confirmed the notion that patients adhering to a ketogenic diet can show reduced cerebral 18F-FDG uptake on PET imaging. According to experts involved in the analysis, this study adds to the mounting evidence suggesting that clinicians should take note of patients’ dietary habits as the keto diet becomes more popular.
“Because of this range of proven and postulated benefits of ketosis, more patients are attending 2-[18F]fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography (PET) of the brain while in therapeutic ketosis,” corresponding author O. A. Bennett of Prince of Wales Hospital in Sydney, Australia, and co-authors explained. “Given that ketones can act as a metabolic substrate for the brain, it is relevant to understand the impact of ketosis on these images.”
Using the imaging of 52 individuals adhering to a ketogenic diet who underwent PET scans of the brain, experts noted a negative association between serum glucose levels and whole brain 18F-FDG uptake in these patients. They found that as serum ketones levels increased, standardized uptake values based on body weight (SUVbw) decreased. This finding was observed in the entire brain, but was most prevalent in the precuneus when compared to the cerebellum or whole brain.
Explaining the significance of these findings, the authors noted that “the 18F-FDG uptake associated with ketones most likely reflects a true reduction in glucose metabolism by the brain due to the preferential use of ketone bodies as an alternate energy substrate independent of glucose availability.”
They added that when SUVs are used to differentiate between pathologic and physiologic states, serum glucose and ketone levels should be considered for patients in therapeutic ketosis.
The detailed study is available in the European Journal of Hybrid Imaging.
In addition to her background in journalism, Hannah also has patient-facing experience in clinical settings, having spent more than 12 years working as a registered rad tech. She joined Innovate Healthcare in 2021 and has since put her unique expertise to use in her editorial role with Health Imaging.