title: Diffusion-weighted signal models in healthy and cancerous peripheral prostate tissues: comparison of outcomes obtained at different b-values.
abstract: OBJECTIVE
  To evaluate the dependence on the b-values adopted of apparent diffusion coefficient (ADC), perfusion fraction (PF), slow and fast diffusion coefficient (Dslow, Dfast), corrected diffusion coefficient (D) and kurtosis (K), in healthy peripheral (HP) and peripheral cancerous (PCa) prostate tissues.
  
  
  METHODS
  Patients who underwent multiparametric prostate MR examination were retrospectively evaluated for possible inclusion. ADC, PF, Dslow, Dfast, D, and K were estimated both in HP and PCa tissues, using three different ranges of b-values: 0-2300, 0-1800, 0-800 s/mm2 (group A, B and C, respectively). Analysis of variance (ANOVA) and receiver operating characteristic (ROC) analysis were performed, to establish differences among groups and to evaluate sensitivity and specificity of every parameter in distinguishing HP and PCa tissues when calculated with different b-values.
  
  
  RESULTS
  In all, 57 patients were included. ANOVA showed significant differences of all parameters between group A-B vs. C, both in HP and PCa tissues. In ROC analysis K showed the best area under the curve (AUC) when calculated in groups A and B (0.87 and 0.86), while it was comparable with the ADC one in group C (both 0.82).
  
  
  CONCLUSIONS
  A significant dependence on the adopted b-values of DWI parameters is shown. The best performance in distinguishing HP from PCa tissues was obtained by K, calculated using a high b-value sequence.
authors.affiliation: Health Physics Unit, Azienda Ospedaliero-Universitaria Careggi, Florence, Italy.
authors.forename: Lorenzo N
authors.initials: LN
authors.lastname: Mazzoni
authors.forename: Silvia
authors.initials: S
authors.lastname: Lucarini
authors.forename: Stefano
authors.initials: S
authors.lastname: Chiti
authors.forename: Simone
authors.initials: S
authors.lastname: Busoni
authors.forename: Cesare
authors.initials: C
authors.lastname: Gori
authors.forename: Ilario
authors.initials: I
authors.lastname: Menchi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D019540:Area Under Curve; D016022:Case-Control Studies; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D008875:Middle Aged; D011467:Prostate / Q000166:cytology*; D011471:Prostatic Neoplasms / Q000175:diagnosis / Q000473:pathology*; D012372:ROC Curve; D012016:Reference Values; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
keywords: ADC; biexponential DWI model; kurtosis; prostate DWI