Blood ketone measurement as a test for dietary compliance in cardiac sarcoid patients undergoing 18f-fluorodeoxyglucose positron emission tomography

Abstract Funding Acknowledgements Type of funding sources: None. Background Imaging with 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) is used as part of diagnosis and monitoring response to therapy in patients with cardiac sarcoidosis. In order to supress myocardial uptake of 18F-FDG patients prepare with a low carbohydrate diet followed by an 18-hour overnight fast. Failure to comply with the protocol results in diffuse myocardial 18F-FDG uptake which confounds diagnostic interpretation. Purpose To assess if point of care blood ketones could be used as a marker of dietary compliance and association with suppression of myocardial 18F-FDG uptake on PET scan. Method Patients (n = 26, 57 ± 4 years, 65% Male) from a single centre were instructed to follow standard preparation protocol prior to 18F-FDG PET/CT. After confirmation of dietary compliance, blood glucose and blood ketones were recorded using point of care devices. Images were graded based on the pattern of myocardial 18F-FDG uptake. Results There was no clear correlation between blood ketones in relation to dietary compliance or myocardial 18F-fluorodeoxyglucose uptake. In those with myocardial 18F-FDG uptake maximum standardized uptake value (SUV max) within the myocardium ranged from 2.3 to 9.8 (Mean 5.3) and ketone from 0.1 – 0.7 (normal