title: Assessment of prostate cancer aggressiveness using dynamic contrast-enhanced magnetic resonance imaging at 3 T.
abstract: BACKGROUND
  A challenge in the diagnosis of prostate cancer (PCa) is the accurate assessment of aggressiveness.
  
  
  OBJECTIVE
  To validate the performance of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) of the prostate at 3 tesla (T) for the assessment of PCa aggressiveness, with prostatectomy specimens as the reference standard.
  
  
  METHODS
  A total of 45 patients with PCa scheduled for prostatectomy were included. This study was approved by the institutional review board; the need for informed consent was waived.
  
  
  METHODS
  Subjects underwent a clinical MRI protocol including DCE-MRI. Blinded to DCE-images, PCa was indicated on T2-weighted images based on histopathology results from prostatectomy specimens with the use of anatomical landmarks for the precise localization of the tumor. PCa was classified as low-, intermediate-, or high-grade, according to Gleason score. DCE-images were used as an overlay on T2-weighted images; mean and quartile values from semi-quantitative and pharmacokinetic model parameters were extracted per tumor region. Statistical analysis included Spearman's ρ, the Kruskal-Wallis test, and a receiver operating characteristics (ROC) analysis.
  
  
  CONCLUSIONS
  Significant differences were seen for the mean and 75th percentile (p75) values of wash-in (p = 0.024 and p = 0.017, respectively), mean wash-out (p = 0.044), and p75 of transfer constant (K(trans)) (p = 0.035), all between low-grade and high-grade PCa in the peripheral zone. ROC analysis revealed the best discriminating performance between low-grade versus intermediate-grade plus high-grade PCa in the peripheral zone for p75 of wash-in, K(trans), and rate constant (Kep) (area under the curve: 0.72). Due to a limited number of tumors in the transition zone, a definitive conclusion for this region of the prostate could not be drawn.
  
  
  CONCLUSIONS
  Quantitative parameters (K(trans) and Kep) and semi-quantitative parameters (wash-in and wash-out) derived from DCE-MRI at 3 T have the potential to assess the aggressiveness of PCa in the peripheral zone. P75 of wash-in, K(trans), and Kep offer the best possibility to discriminate low-grade from intermediate-grade plus high-grade PCa.
authors.affiliation: Department of Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands. e.vos@rad.umcn.nl
authors.forename: Eline K
authors.initials: EK
authors.lastname: Vos
authors.forename: Geert J S
authors.initials: GJ
authors.lastname: Litjens
authors.forename: Thiele
authors.initials: T
authors.lastname: Kobus
authors.forename: Thomas
authors.initials: T
authors.lastname: Hambrock
authors.forename: Christina A
authors.initials: CA
authors.lastname: Hulsbergen-van de Kaa
authors.forename: Jelle O
authors.initials: JO
authors.lastname: Barentsz
authors.forename: Henkjan J
authors.initials: HJ
authors.lastname: Huisman
authors.forename: Tom W J
authors.initials: TW
authors.lastname: Scheenen
mesh_terms: D019540:Area Under Curve; D003287:Contrast Media / Q000493:pharmacokinetics; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008536:Meglumine / Q000493:pharmacokinetics; D060787:Neoplasm Grading; D009942:Organometallic Compounds / Q000493:pharmacokinetics; D011237:Predictive Value of Tests; D011379:Prognosis; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D012372:ROC Curve; D015203:Reproducibility of Results; D012189:Retrospective Studies
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; D008536:Meglumine; C072417:gadoterate meglumine
keywords: Dynamic contrast-enhanced MRI; Pharmacokinetic modeling; Prostate cancer; Prostate cancer aggressiveness; Validation study