title: A randomized trial on the optimization of 18F-FDG myocardial uptake suppression: implications for vulnerable coronary plaque imaging.
abstract: (18)F-FDG PET/CT can be used to detect arterial atherosclerotic plaque inflammation. However, avid myocardial glucose uptake may preclude its use for visualizing coronary plaques. Fatty acid loading or calcium channel blockers could decrease myocardial (18)F-FDG uptake, thus assisting coronary plaque inflammation identification. The present prospective randomized trial compared the efficacies of different interventions for suppressing myocardial (18)F-FDG uptake. We also investigated whether circulating free fatty acid (cFFA) levels predicted the magnitude of myocardial (18)F-FDG uptake.
  
  
  METHODS
  Thirty-six volunteers ate a high-fat low-carbohydrate meal, followed by a 12-h fasting period. They were then randomized to 1 of 4 intervention groups. Group 1 received no additional preparation and served as a reference. Groups 2 and 3, respectively, received a commercial high-fat solution containing 43.8 g of lipids or 50 mL of olive oil 1 h before (18)F-FDG injection to evaluate the impact of fatty acid loading on myocardial (18)F-FDG uptake. Group 4 received verapamil to evaluate the effect of calcium channel blockers. Cardiac PET/CT was performed after administration of 370 MBq of (18)F-FDG. Myocardial uptake suppression was assessed using a qualitative visual scale and by measuring the myocardial maximum standardized uptake value (SUV(max)). Insulin, glucose, and cFFA were serially measured.
  
  
  RESULTS
  The qualitative visual scale showed good myocardial (18)F-FDG uptake suppression in 8 of 9, 5 of 9, 4 of 9, and 8 of 9 subjects of groups 1, 2, 3, and 4, respectively (P = 0.09). SUV(max) did not significantly differ between groups (P = 0.17). Interestingly, cFFA levels were higher in volunteers with good suppression (0.80 ± 0.31 mmol/L) than in those with poor suppression (0.53 ± 0.15 mmol/L; P = 0.011). We found an inverse correlation between cFFA level (measured at (18)F-FDG injection) and the SUV(max) (R = 0.61). Receiver-operating-characteristic curve analysis identified 0.65 mmol/L cFFA as the best cutoff value to predict adequate (18)F-FDG uptake suppression (positive predictive value, 89%).
  
  
  CONCLUSIONS
  A high-fat low-carbohydrate meal followed by a 12-h fasting period effectively suppressed myocardial (18)F-FDG uptake in most subjects. Neither complementary fatty acid loading nor verapamil administered 1 h before (18)F-FDG injection conferred any additional benefit. Myocardial (18)F-FDG uptake was inversely correlated with cFFA level, representing an interesting way to predict myocardial (18)F-FDG uptake suppression.
authors.affiliation: From the Pôle de Recherche Cardiovasculaire (CARD), Institut de Recherche Expérimentale et Clinique (IREC), Université Catholique de Louvain, Brussels, Belgium.
authors.forename: Fabian
authors.initials: F
authors.lastname: Demeure
authors.affiliation: From the Pôle d'imagerie Médicale, Radiothérapie et Oncologie (MIRO), Institut de Recherche Expérimentale et Clinique (IREC), Université Catholique de Louvain, Brussels, Belgium; and.
authors.forename: François-Xavier
authors.initials: FX
authors.lastname: Hanin
authors.affiliation: From the Pôle d'imagerie Médicale, Radiothérapie et Oncologie (MIRO), Institut de Recherche Expérimentale et Clinique (IREC), Université Catholique de Louvain, Brussels, Belgium; and.
authors.forename: Anne
authors.initials: A
authors.lastname: Bol
authors.affiliation: From the Laboratoire des Maladies Métaboliques et Centre de Dépistage Néonatal, Cliniques Universitaires St-Luc, Université Catholique de Louvain, Brussels, Belgium.
authors.forename: Marie-Françoise
authors.initials: MF
authors.lastname: Vincent
authors.affiliation: From the Pôle de Recherche Cardiovasculaire (CARD), Institut de Recherche Expérimentale et Clinique (IREC), Université Catholique de Louvain, Brussels, Belgium.
authors.forename: Anne-Catherine
authors.initials: AC
authors.lastname: Pouleur
authors.affiliation: From the Pôle de Recherche Cardiovasculaire (CARD), Institut de Recherche Expérimentale et Clinique (IREC), Université Catholique de Louvain, Brussels, Belgium.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Gerber
authors.affiliation: From the Pôle de Recherche Cardiovasculaire (CARD), Institut de Recherche Expérimentale et Clinique (IREC), Université Catholique de Louvain, Brussels, Belgium.
authors.forename: Agnès
authors.initials: A
authors.lastname: Pasquet
authors.affiliation: From the Pôle d'imagerie Médicale, Radiothérapie et Oncologie (MIRO), Institut de Recherche Expérimentale et Clinique (IREC), Université Catholique de Louvain, Brussels, Belgium; and.
authors.forename: François
authors.initials: F
authors.lastname: Jamar
authors.affiliation: From the Pôle de Recherche Cardiovasculaire (CARD), Institut de Recherche Expérimentale et Clinique (IREC), Université Catholique de Louvain, Brussels, Belgium.
authors.forename: Jean-Louis J
authors.initials: JL
authors.lastname: Vanoverschelde
authors.affiliation: From the Pôle de Recherche Cardiovasculaire (CARD), Institut de Recherche Expérimentale et Clinique (IREC), Université Catholique de Louvain, Brussels, Belgium David.Vancraeynest@uclouvain.be.
authors.forename: David
authors.initials: D
authors.lastname: Vancraeynest
mesh_terms: D000328:Adult; D003331:Coronary Vessels / Q000473:pathology*; D004032:Diet; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D064368:Healthy Volunteers; D006801:Humans; D007249:Inflammation; D008055:Lipids / Q000008:administration & dosage; D008297:Male; D000069463:Olive Oil; D010938:Plant Oils / Q000008:administration & dosage / Q000737:chemistry; D058226:Plaque, Atherosclerotic / Q000000981:diagnostic imaging*; D049268:Positron-Emission Tomography / Q000379:methods*; D011446:Prospective Studies; D015203:Reproducibility of Results; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods; D014700:Verapamil / Q000008:administration & dosage
chemical_list: D005230:Fatty Acids, Nonesterified; D008055:Lipids; D000069463:Olive Oil; D010938:Plant Oils; D019788:Fluorodeoxyglucose F18; D014700:Verapamil
keywords: 18F-FDG PET/CT; calcium channel blocker; free fatty acids; inflammation; vulnerable coronary plaque