title: Comparison between intensity normalization techniques for dynamic susceptibility contrast (DSC)-MRI estimates of cerebral blood volume (CBV) in human gliomas.
abstract: OBJECTIVE
  To compare "standardization," "Gaussian normalization," and "Z-score normalization" intensity transformation techniques in dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) estimates of cerebral blood volume (CBV) in human gliomas. DSC-MRI is a well-established biomarker for CBV in brain tumors; however, DSC-MRI estimates of CBV are semiquantitative. The use of image intensity transformation algorithms provides a mechanism for obtaining quantitatively similar CBV maps with the same intensity scaling.
  
  
  METHODS
  The coefficient of variance (CV) in normal-appearing white matter and relative contrast between tumor regions and normal tissue was compared between the three CBV transformations across five different MR scanners in 96 patients with gliomas.
  
  
  RESULTS
  The results suggest all normalization techniques improved variability and relative tumor contrast of CBV measurements compared with nonnormalized CBV maps. The results suggest Gaussian normalization of CBV maps provided slightly lower CV in normal white matter and provided slightly higher tumor contrast for glioblastomas (WHO grade IV) compared with other techniques.
  
  
  CONCLUSIONS
  The results suggest Gaussian normalization of leakage-corrected CBV maps may be the best choice for image intensity correction for use in large-scale, multicenter clinical trials where MR scanners and protocols vary widely due to ease of implementation, lowest variability, and highest tumor to normal tissue contrast.
authors.affiliation: Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California 90024, USA. bellingson@mednet.ucla.edu
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Ellingson
authors.forename: Taryar
authors.initials: T
authors.lastname: Zaw
authors.forename: Timothy F
authors.initials: TF
authors.lastname: Cloughesy
authors.forename: Kourosh M
authors.initials: KM
authors.lastname: Naeini
authors.forename: Shadi
authors.initials: S
authors.lastname: Lalezari
authors.forename: Sandy
authors.initials: S
authors.lastname: Mong
authors.forename: Albert
authors.initials: A
authors.lastname: Lai
authors.forename: Phioanh L
authors.initials: PL
authors.lastname: Nghiemphu
authors.forename: Whitney B
authors.initials: WB
authors.lastname: Pope
mesh_terms: D000368:Aged; D001810:Blood Volume; D001811:Blood Volume Determination / Q000379:methods*; D001932:Brain Neoplasms / Q000473:pathology* / Q000503:physiopathology*; D002560:Cerebrovascular Circulation; D003287:Contrast Media; D003627:Data Interpretation, Statistical; D005910:Glioma / Q000473:pathology* / Q000503:physiopathology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media