title: Assessment of intratumor hypoxia by integrated 18F-FDG PET / perfusion CT in a liver tumor model.
abstract: OBJECTIVE
  Hypoxia in solid tumors occurs when metabolic demands in tumor cells surpass the delivery of oxygenated blood. We hypothesize that the 18F-fluorodeoxyglucose (18F-FDG) metabolism and tumor blood flow mismatch would correlate with tumor hypoxia.
  
  
  METHODS
  Liver perfusion computed tomography (CT) and 18F-FDG positron emission tomography (PET) imaging were performed in twelve rabbit livers implanted with VX2 carcinoma. Under CT guidance, a fiber optic probe was inserted into the tumor to measure the partial pressure of oxygen (pO2). Tumor blood flow (BF) and standardized uptake value (SUV) were measured to calculate flow-metabolism ratio (FMR). Tumor hypoxia was further identified using pimonidazole immunohistochemical staining. Pearson correlation analysis was performed to determine the correlation between the imaging parameters and pO2 and pimonidazole staining.
  
  
  RESULTS
  Weak correlations were found between blood volume (BV) and pO2 level (r = 0.425, P = 0.004), SUV and pO2 (r = -0.394, P = 0.007), FMR and pimonidazole staining score (r = -0.388, P = 0.031). However, there was stronger correlation between tumor FMR and pO2 level (r = 0.557, P < 0.001).
  
  
  CONCLUSIONS
  FMR correlated with tumor oxygenation and pimonidazole staining suggesting it may be a potential hypoxic imaging marker in liver tumor.
authors.affiliation: Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.|Department of Medical Biophysics, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada.
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Imaging Program, Lawson Health Research Institute, London, Ontario, Canada.
authors.forename: Errol
authors.initials: E
authors.lastname: Stewart
authors.affiliation: Imaging Program, Lawson Health Research Institute, London, Ontario, Canada.
authors.forename: Lise
authors.initials: L
authors.lastname: Desjardins
authors.affiliation: Imaging Program, Lawson Health Research Institute, London, Ontario, Canada.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Hadway
authors.affiliation: Imaging Program, Lawson Health Research Institute, London, Ontario, Canada.
authors.forename: Laura
authors.initials: L
authors.lastname: Morrison
authors.affiliation: Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada.
authors.forename: Cathie
authors.initials: C
authors.lastname: Crukley
authors.affiliation: Department of Medical Biophysics, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada.|Imaging Program, Lawson Health Research Institute, London, Ontario, Canada.|Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada.
authors.forename: Ting-Yim
authors.identifier: http://orcid.org/0000-0001-7605-9752
authors.initials: TY
authors.lastname: Lee
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D019788:Fluorodeoxyglucose F18; D005947:Glucose / Q000378:metabolism; D006801:Humans; D000860:Hypoxia / Q000378:metabolism*; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism* / Q000473:pathology; D008297:Male; D009389:Neovascularization, Pathologic / Q000000981:diagnostic imaging / Q000378:metabolism; D009593:Nitroimidazoles / Q000008:administration & dosage / Q000378:metabolism; D010101:Oxygen Consumption; D010477:Perfusion; D000072078:Positron Emission Tomography Computed Tomography; D049268:Positron-Emission Tomography; D011817:Rabbits
chemical_list: D009593:Nitroimidazoles; D019788:Fluorodeoxyglucose F18; C033815:pimonidazole; D005947:Glucose