title: Effect of duration of fasting and diet on the myocardial uptake of F-18-2-fluoro-2-deoxyglucose (F-18 FDG) at rest.
abstract: BACKGROUND
  Patterns of myocardial fluoro-2-deoxyglucose (FDG) uptake with respect to duration of fasting and dietary modifications.
  
  
  OBJECTIVE
  We observed the effect of duration of fasting and diet on the myocardial uptake pattern of F-18 FDG in patients routinely referred for oncological evaluation and no previous history of Coronary Artery Disease (CAD).
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  A total of 153 patients (M: 81, F: 72; mean age: 47 ± 15 years; mean blood glucose level (mBG) 105 ± 23 mg/dl) were randomly divided in three groups. Group A: 4-6 h fasting; Group B: Overnight fasting (12-14 h); Group C: Low carbohydrate and fat rich diet for 2 days coupled with overnight fasting prior to the positron emission tomography (PET) scan. FDG uptake was classified as following: 1) homogeneous uptake, 2) heterogeneous uptake, and 3) 'no uptake' in the left ventricular (LV) myocardium. FDG PET study was performed as standard protocol for oncological conditions.
  
  
  METHODS
  Descriptive statistics, Chi-square test or Fisher's exact test, and Spearman's rank correlation tests were applied.
  
  
  RESULTS
  We observed the 'no uptake' pattern in five (10%), 28 (55%), and 39 (77%), 'heterogeneous' pattern in 20 (39%), 14 (28%), and seven (14%), and 'homogeneous' pattern in 26 (51%), nine (18%), and five (10%) patients in Group A, B, and C, respectively. There was statistically significant difference of myocardial uptake pattern between group A and B (P < 0.0001), between group A and C (P < 0.0001), and between Group B and C (P = 0.023). The mBG was 102, 105, and 111 mg/dl in 'no uptake', heterogeneous, and homogeneous uptake pattern, respectively, (P = 0.103). Also, within each group the mBG was not related to the uptake pattern.
  
  
  CONCLUSIONS
  Both restricted diet and duration of fasting play an important role in determining the pattern and suppression of myocardial F-18 FDG uptake. Overnight fasting and restricted diet together suppress myocardial FDG uptake more than overnight fasting alone, which suppresses uptake more than 4-h fasting.
authors.affiliation: Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Pankaj
authors.initials: P
authors.lastname: Kumar
authors.affiliation: Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Chetan D
authors.initials: CD
authors.lastname: Patel
authors.affiliation: Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Suhas
authors.initials: S
authors.lastname: Singla
authors.affiliation: Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: A
authors.initials: A
authors.lastname: Malhotra
keywords: Fasting; fat-rich diet; fluoro-2-deoxyglucose; low carbohydrate; myocardial uptake; no uptake