title: Relationship Between [18F]FDOPA PET Uptake, Apparent Diffusion Coefficient (ADC), and Proliferation Rate in Recurrent Malignant Gliomas.
abstract: OBJECTIVE
  Diffusion magnetic resonance imaging (MRI) and 6-[(18)F]fluoro-L-dopa ([(18)F]FDOPA) positron emission tomography (PET) are used to interrogate malignant tumor microenvironment. It remains unclear whether there is a relationship between [(18)F]FDOPA uptake, diffusion MRI estimates of apparent diffusion coefficient (ADC), and mitotic activity in the context of recurrent malignant gliomas, where the tumor may be confounded by the effects of therapy. The purpose of the current study is to determine whether there is a correlation between these imaging techniques and mitotic activity in malignant gliomas.
  
  
  METHODS
  We retrospectively examined 29 patients with recurrent malignant gliomas who underwent structural MRI, diffusion MRI, and [(18)F]FDOPA PET prior to surgical resection. Qualitative associations were noted, and quantitative voxel-wise and median measurement correlations between [(18)F]FDOPA PET, ADC, and mitotic index were performed.
  
  
  RESULTS
  Areas of high [(18)F]FDOPA uptake exhibited low ADC and areas of hyperintensity T2/fluid-attenuated inversion recovery (FLAIR) with low [(18)F]FDOPA uptake exhibited high ADC. There was a significant inverse voxel-wise correlation between [(18)F]FDOPA and ADC for all patients. Median [(18)F]FDOPA uptake and median ADC also showed a significant inverse correlation. Median [(18)F]FDOPA uptake was positively correlated, and median ADC was inversely correlated with mitotic index from resected tumor tissue.
  
  
  CONCLUSIONS
  A significant association may exist between [(18)F]FDOPA uptake, diffusion MRI, and mitotic activity in recurrent malignant gliomas.
authors.affiliation: Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, 924 Westwood Blvd, Suite 615, Los Angeles, CA, 90024, USA.
authors.forename: Elena
authors.initials: E
authors.lastname: Karavaeva
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Harris
authors.forename: Kevin
authors.initials: K
authors.lastname: Leu
authors.forename: Maryam
authors.initials: M
authors.lastname: Shabihkhani
authors.forename: William H
authors.initials: WH
authors.lastname: Yong
authors.forename: Whitney B
authors.initials: WB
authors.lastname: Pope
authors.forename: Albert
authors.initials: A
authors.lastname: Lai
authors.forename: Phioanh L
authors.initials: PL
authors.lastname: Nghiemphu
authors.forename: Linda M
authors.initials: LM
authors.lastname: Liau
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.forename: Johannes
authors.initials: J
authors.lastname: Czernin
authors.forename: Timothy F
authors.initials: TF
authors.lastname: Cloughesy
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Ellingson
mesh_terms: D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D049109:Cell Proliferation; D003287:Contrast Media / Q000737:chemistry; D004058:Diffusion; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives* / Q000737:chemistry; D005260:Female; D005910:Glioma / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D007249:Inflammation; D019394:Ki-67 Antigen / Q000378:metabolism; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D008938:Mitosis; D008940:Mitotic Index; D009364:Neoplasm Recurrence, Local; D049268:Positron-Emission Tomography; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D003287:Contrast Media; D019394:Ki-67 Antigen; C043437:fluorodopa F 18; D004295:Dihydroxyphenylalanine