The detection of infectious endocarditis may be enhanced by a repeat FDG-PET while maintaining patients on a ketogenic diet

Background This study aims to determine whether the suppression of myocardial FDG uptake and detection of infectious endocarditis (IE) may be enhanced when FDG-PET is repeated on the next day while maintaining patients on a ketogenic diet in the interim. Methods Seventeen patients with definite IE underwent FDG-PET investigations both after a conventional metabolic preparation (> 12-hour fast after a low-carbohydrate evening meal) and a subsequent 12-hour extension of the low-carbohydrate diet followed by an additional > 12-hour fast. Results Plasma biomarkers showed increased ketogenic metabolism between the two FDG-PET scans. A myocardial FDG uptake persisted on the 1st PET in 9 patients (53%) for whom myocardial FDG uptake decreased significantly on the 2nd PET (SUVmax: 6.05 ± 3.25 vs 4.32 ± 3.47, P = 0.021), resulting in an enhancement in the diagnostic confidence of IE in 6 cases. These enhancements were not documented in the 8 patients exhibiting a total suppression of myocardial FDG uptake on the 1st PET. Conclusions Better suppression of myocardial uptake and enhanced detection of IE may be achieved when an FDG-PET, showing an incomplete suppression of the myocardial FDG uptake, is repeated as soon as the next day, while maintaining patients on a ketogenic diet in the interim.