title: Variability of Hepatic 18F-FDG Uptake at Interim PET in Patients With Hodgkin Lymphoma.
abstract: BACKGROUND
  When evaluating response of Hodgkin lymphoma (HL) to chemotherapy on interim (18)F-FDG-PET/CT, physiological liver uptake is used as reference. Hodgkin lymphoma sites with uptake greater than liver are interpreted as positive. We aimed at examining factors that might influence liver uptake as reference organ.
  
  
  METHODS
  Fifty patients with HL who received baseline (18)F-FDG-PET/CT (PET1) and interim PET (PET2), usually after 2 cycles of adriamycin bleomycin, vinblastine, and dacarbazine chemotherapy, were included retrospectively. SUVmean normalized for body weight (SUVmean) and for lean body mass (SULmean) were obtained from regions of interest in the right lobe of the liver.
  
  
  RESULTS
  On univariate analysis, liver SUVmean on interim PET increased with increasing body mass index (BMI) (P = 0.0453) and were higher in women (P = 0.0401). These factors remained significant on multivariate analysis (P = 0.009 and P = 0.008, respectively). No significant correlation was found with postinjection delay, blood glucose level, and age. Liver SULmean were not affected by the studied variables. Average liver SUVmean in the 50 patients were similar at baseline and interim PET. In 11 patients (22%), however, there was 30% or greater variation in liver SUVmean between PET1 and PET2. No factors explaining intrapatient variation in hepatic uptake between PET1 and PET2 were found on correlation analysis.
  
  
  CONCLUSIONS
  At interim PET in patients with HL, liver SUVmean depends on BMI and sex, but not liver SULmean. Furthermore, our study, conducted with standard clinical procedure, also confirmed the high range of liver uptake values from one patient to another. Caution is required when using liver SUV as reference in patients with high BMI. Intrapatient fluctuation in liver SUVmean should also be expected.
authors.affiliation: From the *Department of Nuclear Medicine, PET/CT Centre, Radiology, Medical Physics, 'Santa Maria della Misericordia' Hospital, Rovigo, Italy; †Department of Nuclear Medicine, Haut-Lévêque Hospital, CHU Bordeaux, University of Bordeaux, Bordeaux, France; ‡Institut de Santé Publique, d'Epidémiologie et de Développement, University of Bordeaux, Bordeaux, France; and §Department of Radiology, University of Southern California, Los Angeles, CA.
authors.forename: Domenico
authors.initials: D
authors.lastname: Rubello
authors.forename: Pierre
authors.initials: P
authors.lastname: Gordien
authors.forename: Camille
authors.initials: C
authors.lastname: Morliere
authors.forename: Martine
authors.initials: M
authors.lastname: Guyot
authors.forename: Laurence
authors.initials: L
authors.lastname: Bordenave
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Colletti
authors.forename: Elif
authors.initials: E
authors.lastname: Hindié
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D015992:Body Mass Index; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D006689:Hodgkin Disease / Q000000981:diagnostic imaging*; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D012737:Sex Factors
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18