title: Do high glucose levels have differential effect on FDG uptake in inflammatory and malignant disorders?
abstract: BACKGROUND
  The association of hyperglycaemia with reduced fluorodeoxyglucose (FDG) uptake by tumour cells is well established. Therefore, it is standard practice that all patients must fast for at least several hours prior to FDG positron emission tomography (PET) imaging. However, the effect of hyperglycaemia on FDG uptake by inflammatory and infectious lesions is unknown. The aim of this study was to investigate this important issue.
  
  
  METHODS
  For in vitro studies human mononuclear cells were isolated from 12 normal volunteers and FDG uptake was determined in medium containing differing concentrations of glucose. FDG uptake by human mesothelioma cells was also measured for comparison. For studies involving patients, 416 FDG PET scans of patients with confirmed malignancy (n=321) or benign lesions (n=95) were reviewed retrospectively. The relationship between serum glucose level and FDG uptake by the lesions was assessed utilizing the standardized uptake value (SUV) technique.
  
  
  RESULTS
  In the in vitro studies, while FDG uptake by mesothelioma cells decreased as glucose concentration increased, there was no differential uptake of FDG uptake by mononuclear cells at glucose concentrations less than 250 mg x dl(-1). In clinical patients, FDG uptake by malignant lesions was slightly, but negatively affected by serum glucose level (r= -0.21, P<0.01) (glucose range 49-187 mg x dl(-1)). In contrast, FDG uptake by inflammatory lesions was positively associated with serum glucose level (r=0.43, P<0.01) (glucose range 54-215 mg x dl(-1)).
  
  
  CONCLUSIONS
  While the degree of FDG uptake is primarily influenced by the nature of the underlying lesion, serum glucose concentration appears to have a small effect on FDG uptake, which differs between malignant disorders and inflammatory processes. Our data suggest that below a certain level, elevated glucose concentration might not have a negative effect on FDG uptake in inflammatory cells, contrary to that observed in malignant disorders.
authors.affiliation: Division of Nuclear Medicine, The Hospital of the University of Pennsylvania, Philadelphia 19104, USA.
authors.forename: H M
authors.initials: HM
authors.lastname: Zhuang
authors.forename: A
authors.initials: A
authors.lastname: Cortés-Blanco
authors.forename: M
authors.initials: M
authors.lastname: Pourdehnad
authors.forename: L E
authors.initials: LE
authors.lastname: Adam
authors.forename: A J
authors.initials: AJ
authors.lastname: Yamamoto
authors.forename: R
authors.initials: R
authors.lastname: Martínez-Lázaro
authors.forename: J H
authors.initials: JH
authors.lastname: Lee
authors.forename: J C
authors.initials: JC
authors.lastname: Loman
authors.forename: M D
authors.initials: MD
authors.lastname: Rossman
authors.forename: A
authors.initials: A
authors.lastname: Alavi
mesh_terms: D001786:Blood Glucose / Q000378:metabolism*; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D006801:Humans; D007249:Inflammation / Q000000981:diagnostic imaging* / Q000378:metabolism*; D008654:Mesothelioma / Q000378:metabolism; D009000:Monocytes / Q000000981:diagnostic imaging / Q000378:metabolism; D009369:Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D012189:Retrospective Studies; D014055:Tomography, Emission-Computed; D014407:Tumor Cells, Cultured
chemical_list: D001786:Blood Glucose; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18