title: The effects of 18-h fasting with low-carbohydrate diet preparation on suppressed physiological myocardial (18)F-fluorodeoxyglucose (FDG) uptake and possible minimal effects of unfractionated heparin use in patients with suspected cardiac involvement sarcoidosis.
abstract: BACKGROUND
  (18)F-fluorodeoxyglucose (FDG) PET plays an important role in the detection of cardiac involvement sarcoidosis (CS). However, diffuse left ventricle (LV) wall uptake sometimes makes it difficult to distinguish between positive uptake and physiological uptake. The aims of this study were to evaluate the effects of 18-h fasting with low-carbohydrate diet (LCD) vs a minimum of 6-h fasting preparations on diffuse LV FDG uptake and free fatty acid (FFA) levels in patients with suspected CS.
  
  
  METHODS
  Eighty-two patients with suspected CS were divided into 2 preparation protocols: one with a minimum 6-h fast without LCD preparation (group A, n = 58) and the other with a minimum 18-h fast with LCD preparation (group B, n = 24). All patients also received intravenous unfractionated heparin (UFH; 50 IU/kg) before the injection of FDG.
  
  
  RESULTS
  Group A showed a higher percentage of diffuse LV uptake than did group B (27.6 vs 0.0%, P = .0041). Group B showed higher FFA levels (1159.1  ±  393.0, 650.5  ±  310.9 μEq/L, P < .0001) than did group A. Patients with diffuse LV uptake (n = 16) showed lower FFA levels than did other patients (n = 66) (432.1  ±  296.1, 888.4  ±  381.4 μEq/L, P < .0001). UFH administration significantly increased FFAs in both groups, even in the patients with diffuse LV FDG uptake.
  
  
  CONCLUSIONS
  The 18-h fast with LCD preparation significantly reduced diffuse LV uptake and increased FFA levels. In particular, the FFA level was significantly lower in patients with LV diffuse uptake than in patients without LV diffuse uptake. Acutely increasing plasma FFA through the use of UFH may not have a significant role in reducing physiological LV FDG uptake.
authors.affiliation: Department of Nuclear Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Manabe
authors.affiliation: Department of Nuclear Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan. kyoshi@nirs.go.jp.|Molecular Imaging Research Center, National Institute of Radiological Science, 4-9-1 Anage, Inage-Ku, Chiba, 263-8555, Japan. kyoshi@nirs.go.jp.
authors.forename: Keiichiro
authors.initials: K
authors.lastname: Yoshinaga
authors.affiliation: First Department of Medicine, Hokkaido University Hospital, Sapporo, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ohira
authors.affiliation: Department of Nuclear Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Atsuro
authors.initials: A
authors.lastname: Masuda
authors.affiliation: First Department of Medicine, Hokkaido University Hospital, Sapporo, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Sato
authors.affiliation: First Department of Medicine, Hokkaido University Hospital, Sapporo, Japan.
authors.forename: Ichizo
authors.initials: I
authors.lastname: Tsujino
authors.affiliation: First Department of Medicine, Hokkaido University Hospital, Sapporo, Japan.
authors.forename: Asuka
authors.initials: A
authors.lastname: Yamada
authors.affiliation: Diagnostic and Interventional Radiology, Hokkaido University Hospital, Sapporo, Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Oyama-Manabe
authors.affiliation: Department of Nuclear Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Hirata
authors.affiliation: First Department of Medicine, Hokkaido University Hospital, Sapporo, Japan.
authors.forename: Masaharu
authors.initials: M
authors.lastname: Nishimura
authors.affiliation: Department of Nuclear Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Nagara
authors.initials: N
authors.lastname: Tamaki
mesh_terms: D000328:Adult; D000368:Aged; D009202:Cardiomyopathies / Q000000981:diagnostic imaging*; D050528:Diet, Carbohydrate-Restricted; D005215:Fasting; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D006493:Heparin / Q000494:pharmacology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D000072078:Positron Emission Tomography Computed Tomography; D012507:Sarcoidosis / Q000000981:diagnostic imaging*
chemical_list: D005230:Fatty Acids, Nonesterified; D019788:Fluorodeoxyglucose F18; D006493:Heparin
keywords: 18F-fluorodeoxyglucose; Cardiac sarcoidosis; free fatty acid; long fasting; positron emission tomography