title: Early dynamic 18F-FDG PET to detect hyperperfusion in hepatocellular carcinoma liver lesions.
abstract: In addition to angiographic data on vascularity and vascular access, demonstration of hepatocellular carcinoma (HCC) liver nodule hypervascularization is a prerequisite for certain intrahepatic antitumor therapies. Early dynamic (ED) (18)F-FDG PET/CT could serve this purpose when the current standard method, contrast-enhanced (CE) CT, or other CE morphologic imaging modalities are unsuitable. A recent study showed ED (18)F-FDG PET/CT efficacy in this setting but applied a larger-than-standard (18)F-FDG activity and an elaborate protocol likely to hinder routine use. We developed a simplified protocol using standard activities and easily generated visual and descriptive or quantitative endpoints. This pilot study assessed the ability of these endpoints to detect HCC hyperperfusion and, thereby, evaluated the suitability in of the protocol everyday practice.
  
  
  METHODS
  Twenty-seven patients with 34 HCCs (diameter ≥ 1.5 cm) with hypervascularization on 3-phase CE CT underwent liver ED (18)F-FDG PET for 240 s, starting with (18)F-FDG (250-MBq bolus injection). Four frames at 15-s intervals, followed by 3 frames at 60-s intervals were reconstructed. Endpoints included focal tracer accumulation in the first 4 frames (60 s), subsequent focal washout, and visual and quantitative differences between tumor and liver regions of interest in maximum and mean ED standardized uptake value (ED SUVmax and ED SUVmean, respectively) 240-s time-activity curves.
  
  
  RESULTS
  All 34 lesions were identified by early focal (18)F-FDG accumulation and faster time-to-peak ED SUVmax or ED SUVmean than in nontumor tissue. Tumor peak ED SUVmax and ED SUVmean exceeded liver levels in 85% and 53%, respectively, of lesions. Nadir tumor signal showed no consistent pattern relative to nontumor signal. HCC had a significantly shorter time to peak and significantly faster rate to peak for both ED SUVmax and ED SUVmean curves and a significantly higher peak ED SUVmax but not peak ED SUVmean than the liver.
  
  
  CONCLUSIONS
  This pilot study provided proof of principle that our simplified ED (18)F-FDG PET/CT protocol includes endpoints that effectively detect HCC hypervascularization; this finding suggests that the protocol can be used routinely.
authors.affiliation: Clinic of Nuclear Medicine, Jena University Hospital, Jena, Germany.
authors.forename: Jan-Henning
authors.initials: JH
authors.lastname: Schierz
authors.forename: Thomas
authors.initials: T
authors.lastname: Opfermann
authors.forename: Jörg
authors.initials: J
authors.lastname: Steenbeck
authors.forename: Eric
authors.initials: E
authors.lastname: Lopatta
authors.forename: Utz
authors.initials: U
authors.lastname: Settmacher
authors.forename: Andreas
authors.initials: A
authors.lastname: Stallmach
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Marlowe
authors.forename: Martin
authors.initials: M
authors.lastname: Freesmeyer
mesh_terms: D000328:Adult; D000368:Aged; D001775:Blood Circulation; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D023381:Endpoint Determination; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009389:Neovascularization, Pathologic / Q000000981:diagnostic imaging; D049268:Positron-Emission Tomography; D013997:Time Factors; D051598:Whole Body Imaging
chemical_list: D019788:Fluorodeoxyglucose F18
keywords: contrast-enhanced computed tomography; early dynamic 18F-fluorodeoxyglucose-positron emission tomography; hepatocellular carcinoma; hypervascularization; liver