title: Impacts of biological and procedural factors on semiquantification uptake value of liver in fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography imaging.
abstract: BACKGROUND
  Increased metabolic activity of fluorodeoxyglucose (FDG) in tissue is not only resulting of pathological uptake, but due to physiological uptake as well. This study aimed to determine the impacts of biological and procedural factors on FDG uptake of liver in whole body positron emission tomography/computed tomography (PET/CT) imaging.
  
  
  METHODS
  Whole body fluorine-18 ((18)F) FDG PET/CT scans of 51 oncology patients have been reviewed. Maximum standardized uptake value (SUVmax) of lesion-free liver was quantified in each patient. Pearson correlation was performed to determine the association between the factors of age, body mass index (BMI), blood glucose level, FDG dose and incubation period and liver SUVmax. Multivariate regression analysis was established to determine the significant factors that best predicted the liver SUVmax. Then the subjects were dichotomised into four BMI groups. Analysis of variance (ANOVA) was established for mean difference of SUVmax of liver between those BMI groups.
  
  
  RESULTS
  BMI and incubation period were significantly associated with liver SUVmax. These factors were accounted for 29.6% of the liver SUVmax variance. Statistically significant differences were observed in the mean SUVmax of liver among those BMI groups (P<0.05).
  
  
  CONCLUSIONS
  BMI and incubation period are significant factors affecting physiological FDG uptake of liver. It would be recommended to employ different cut-off value for physiological liver SUVmax as a reference standard for different BMI of patients in PET/CT interpretation and use a standard protocol for incubation period of patient to reduce variation in physiological FDG uptake of liver in PET/CT study.
authors.affiliation: 1 Faculty of Medicine and Health Sciences, 2 Centre for Diagnostic Nuclear Imaging, Universiti Putra Malaysia, Selangor, Malaysia ; 3 Department of Medical Imaging, Faculty of Health Sciences, Universiti Teknologi MARA Puncak Alam Campus, Selangor, Malaysia ; 4 Department of Community Health, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Selangor, Malaysia.
authors.forename: Mohd Hafizi
authors.initials: MH
authors.lastname: Mahmud
authors.affiliation: 1 Faculty of Medicine and Health Sciences, 2 Centre for Diagnostic Nuclear Imaging, Universiti Putra Malaysia, Selangor, Malaysia ; 3 Department of Medical Imaging, Faculty of Health Sciences, Universiti Teknologi MARA Puncak Alam Campus, Selangor, Malaysia ; 4 Department of Community Health, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Selangor, Malaysia.
authors.forename: Abdul Jalil
authors.initials: AJ
authors.lastname: Nordin
authors.affiliation: 1 Faculty of Medicine and Health Sciences, 2 Centre for Diagnostic Nuclear Imaging, Universiti Putra Malaysia, Selangor, Malaysia ; 3 Department of Medical Imaging, Faculty of Health Sciences, Universiti Teknologi MARA Puncak Alam Campus, Selangor, Malaysia ; 4 Department of Community Health, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Selangor, Malaysia.
authors.forename: Fathinul Fikri
authors.initials: FF
authors.lastname: Ahmad Saad
authors.affiliation: 1 Faculty of Medicine and Health Sciences, 2 Centre for Diagnostic Nuclear Imaging, Universiti Putra Malaysia, Selangor, Malaysia ; 3 Department of Medical Imaging, Faculty of Health Sciences, Universiti Teknologi MARA Puncak Alam Campus, Selangor, Malaysia ; 4 Department of Community Health, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Selangor, Malaysia.
authors.forename: Ahmad Zaid Fattah
authors.initials: AZ
authors.lastname: Azman
keywords: Fluorine-18 fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT); body mass index (BMI); incubation period; liver; maximum standardized uptake value (SUVmax)