title: Multiparametric Magnetic Resonance Imaging for Discriminating Low-Grade From High-Grade Prostate Cancer.
abstract: OBJECTIVE
  The aim of this study was to determine and validate the optimal combination of parameters derived from 3-T diffusion-weighted imaging, dynamic contrast-enhanced imaging, and magnetic resonance (MR) spectroscopic imaging for discriminating low-grade from high-grade prostate cancer (PCa).
  
  
  METHODS
  The study was approved by the institutional review board, and the need for informed consent was waived. Ninety-four patients with PCa who had undergone multiparametric MR imaging (MRI) before prostatectomy were included. Cancer was indicated on T2-weighted images, blinded to any functional data, with prostatectomy specimens as the reference standard. Tumors were classified as low grade or high grade based on Gleason score; peripheral zone (PZ) and transition zone (TZ) tumors were analyzed separately. In a development set (43 patients), the optimal combination of multiparametric MRI parameters was determined using logistic regression modeling. Subsequently, this combination was evaluated in a separate validation set (51 patients).
  
  
  RESULTS
  In the PZ, the 25th percentile of apparent diffusion coefficient (ADC) derived from diffusion-weighted imaging and washout (WO25) derived from dynamic contrast-enhanced MRI offered the optimal combination of parameters. In the TZ, WO25 and the choline over spermine + creatine ratio (C/SC) derived from MR spectroscopic imaging showed the highest discriminating performance. Using the models built with the development set, 48 (74%) of 65 cancer lesions were classified correctly in the validation set.
  
  
  CONCLUSIONS
  Multiparametric MRI is a useful tool for the discrimination between low-grade and high-grade PCa and performs better than any individual functional parameter in both the PZ and TZ. The 25th percentile of ADC + WO25 offered the optimal combination in the PZ, and the choline over spermine + creatine ratio + WO25 offered the optimal combination in the TZ. The ADC parameter has no additional value for the assessment of PCa aggressiveness in the TZ.
authors: From the Departments of *Radiology and Nuclear Medicine, and †Pathology, Radboud University Medical Center, Nijmegen, the Netherlands.
authors: Eline K
authors: EK
authors: Vos
authors: Thiele
authors: T
authors: Kobus
authors: Geert J S
authors: GJ
authors: Litjens
authors: Thomas
authors: T
authors: Hambrock
authors: Christina A
authors: CA
authors: Hulsbergen-van de Kaa
authors: Jelle O
authors: JO
authors: Barentsz
authors: Marnix C
authors: MC
authors: Maas
authors: Tom W J
authors: TW
authors: Scheenen
mesh_terms: D000328:Adult; D000368:Aged; D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D007089:Image Enhancement; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D011467:Prostate / Q000473:pathology; D011471:Prostatic Neoplasms / Q000473:pathology*; D012372:ROC Curve; D015203:Reproducibility of Results
chemical_list: D003287:Contrast Media