Suppression of myocardial glucose metabolism in FDG PET/CT: impact of dose variation in heparin bolus pre-administration.
INTRODUCTION
Adequate suppression of physiologic myocardial glucose uptake is important to ensure the interpretability and diagnostic reliability of [18F]fluorodeoxyglucose (FDG) PET/CT studies performed in the context of cardiac inflammation and infection. This study describes our experience with 4 preparatory protocols used in our institution.


METHODS
FDG PET/CT scans were performed according to 4 preparatory protocols (716 scans total), i.e. 6-h fast (group 1), low-carbohydrate diet plus 12-h fast (group 2), low-carbohydrate diet plus 12-h fast plus intravenous heparin pre-administration (15 IU/kg) (group 3), and low-carbohydrate diet plus 12-h fast plus intravenous heparin pre-administration (50 IU/kg) (group 4). Consecutive scans were retrospectively included from time frames during which the particular protocol was used. FDG uptake in normal myocardium was scored on a scale ranging from 0 (uptake less than that in the left ventricular blood pool) to 4 (diffuse uptake greater than that in the liver). Complete suppression was defined as uptake less than or equal to the blood pool (scores 0-1).


RESULTS
Complete suppression was accomplished in 27% in group 1, 68% in group 2, 69% in group 3 and 81% in group 4. Complete suppression was significantly lower in group 1 compared with all other groups (P < 0.0001 for all comparisons) and significantly higher in group 4 compared with group 2 (P = 0.005) and group 3 (P = 0.007). Groups 2 and 3 did not differ significantly (P = 0.92).


CONCLUSION
A total of 50 IU/kg single-dose heparin administration before FDG PET/CT in addition to a low-carbohydrate diet and prolonged fast significantly outperformed protocols with no or lower dose (15 IU/kg) heparin in completely suppressing myocardial glucose metabolism.
['Scholtens|A M|AM|http://orcid.org/0000-0003-3894-5010', 'van den Berk|A M|AM|', 'van der Sluis|N L|NL|', 'Esser|J P|JP|', 'Lammers|G K|GK|', 'de Klerk|J M H|JMH|', 'Lam|M G E H|MGEH|', 'Verberne|H J|HJ|']
D019788:Fluorodeoxyglucose F18 D005947:Glucose D006493:Heparin D006801:Humans D009206:Myocardium D000072078:Positron Emission Tomography Computed Tomography D019275:Radiopharmaceuticals D015203:Reproducibility of Results D012189:Retrospective Studies
FDG PET/CT Heparin Inflammation Infection Cardiac glucose metabolism Low carbohydrate diet