title: Tissue Microstructure Is Linked to MRI Parameters and Metabolite Levels in Prostate Cancer.
abstract: BACKGROUND
  Magnetic resonance imaging (MRI) can portray spatial variations in tumor heterogeneity, architecture, and its microenvironment in a non-destructive way. The objective of this study was to assess the relationship between MRI parameters measured on patients in vivo, individual metabolites measured in prostatectomy tissue ex vivo, and quantitative histopathology.
  
  
  METHODS
  Fresh frozen tissue samples (n = 53 from 15 patients) were extracted from transversal prostate slices and linked to in vivo MR images, allowing spatially matching of ex vivo measured metabolites with in vivo MR parameters. Color-based segmentation of cryosections of each tissue sample was used to identify luminal space, stroma, and nuclei.
  
  
  RESULTS
  Cancer samples have significantly lower area percentage of lumen and higher area percentage of nuclei than non-cancer samples (p ≤ 0.001). Apparent diffusion coefficient is significantly correlated with percentage area of lumen (ρ = 0.6, p < 0.001) and percentage area of nuclei (ρ = -0.35, p = 0.01). There is a positive correlation (ρ = 0.31, p = 0.053) between citrate and percentage area of lumen. Choline is negatively correlated with lumen (ρ = -0.38, p = 0.02) and positively correlated with percentage area of nuclei (ρ = 0.38, p = 0.02).
  
  
  CONCLUSIONS
  Microstructures that are observed by histopathology are linked to MR characteristics and metabolite levels observed in prostate cancer.
authors.affiliation: Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway; St. Olavs Hospital, Trondheim, Norway.
authors.forename: Kirsten Margrete
authors.initials: KM
authors.lastname: Selnæs
authors.affiliation: Department of Circulation and Medical Imaging, Norwegian University of Science and Technology , Trondheim , Norway.
authors.forename: Riyas
authors.initials: R
authors.lastname: Vettukattil
authors.affiliation: Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway; Department of Urology, St. Olavs Hospital, Trondheim, Norway.
authors.forename: Helena
authors.initials: H
authors.lastname: Bertilsson
authors.affiliation: Cancer Research UK Cambridge Institute, University of Cambridge , Cambridge , UK.
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Wright
authors.affiliation: Department of Radiology and Nuclear Medicine, Radboud University Medical Center , Nijmegen , Netherlands.
authors.forename: Arend
authors.initials: A
authors.lastname: Heerschap
authors.affiliation: Department of Circulation and Medical Imaging, Norwegian University of Science and Technology , Trondheim , Norway.
authors.forename: Anders
authors.initials: A
authors.lastname: Angelsen
authors.affiliation: Department of Circulation and Medical Imaging, Norwegian University of Science and Technology , Trondheim , Norway.
authors.forename: May-Britt
authors.initials: MB
authors.lastname: Tessem
authors.affiliation: Department of Circulation and Medical Imaging, Norwegian University of Science and Technology , Trondheim , Norway.
authors.forename: Tone Frost
authors.initials: TF
authors.lastname: Bathen
keywords: ADC; HR-MAS MRS; choline; citrate; color-based segmentation; magnetic resonance imaging