title: Inter-reader agreement of multi-parametric MR imaging for the detection of prostate cancer: evaluation of a scoring system.
abstract: OBJECTIVE
  Functional prostate MR is performed in varying combinations of T2-weighted images with diffusion-weighted imaging (DWI), dynamic contrast-enhanced MRI (DCE-MRI), and spectroscopic imaging (MRSI). Recently, a European consensus meeting proposed the use of a simple 5-point scale for estimating the probability of a lesion being malignant. The aim of the present study was to determine the inter-reader agreement of MR imaging using a scoring system based on the recommendations of the consensus.
  
  
  METHODS
  The appearance of 108 predefined lesions in three different MR sequences (T2-weighted images, DWI, and DCE-MRI) in 50 functional prostate MR examinations were retrospectively scored by three blinded radiologists using a 5-point scale for each MR sequence. After scoring T2/DWI and T2/DWI/DCE-MRI, every lesion was graded based on its probability for malignancy. The inter-observer reliability was evaluated using Kappa statistics (ĸ).
  
  
  RESULTS
  With respect to T2-weighted images, DWI and DCE-MRI ĸ was 0.49, 0.97, and 0.77, respectively. Combined scoring of T2-weighted images and DWI demonstrated correct tumor diagnosis (true positive) in 71-88% (depending on reader) of cases (ĸ=0.78). The accuracy was further improved to 88-96% after scoring all three MR sequences including DCE-MRI (ĸ=0.90).
  
  
  CONCLUSIONS
  The use of a simple 5-point scoring system for T2-weighted images, DWI, and DCE-MRI is feasible in functional prostate MRI and has high inter-observer reliability.
authors: Institut für Diagnostische und Interventionelle Radiologie, Medizinische Fakultät, Heinrich-Heine-Universität Düsseldorf, Germany.
authors: M
authors: M
authors: Quentin
authors: C
authors: C
authors: Arsov
authors: S
authors: S
authors: Röhlen
authors: J
authors: J
authors: Klasen
authors: G
authors: G
authors: Antoch
authors: P
authors: P
authors: Albers
authors: D
authors: D
authors: Blondin
mesh_terms: D000328:Adult; D000368:Aged; D001706:Biopsy; D003287:Contrast Media / Q000008:administration & dosage; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods* / Q000706:statistics & numerical data*; D017352:Echo-Planar Imaging / Q000379:methods* / Q000706:statistics & numerical data*; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods* / Q000706:statistics & numerical data*; D008279:Magnetic Resonance Imaging / Q000379:methods* / Q000706:statistics & numerical data*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods* / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D015588:Observer Variation; D011336:Probability; D011467:Prostate / Q000473:pathology; D011471:Prostatic Neoplasms / Q000175:diagnosis*; D012107:Research Design / Q000706:statistics & numerical data*; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media