title: Clinical utility of apparent diffusion coefficient values obtained using high b-value when diagnosing prostate cancer using 3 tesla MRI: comparison between ultra-high b-value (2000 s/mm²) and standard high b-value (1000 s/mm²).
abstract: OBJECTIVE
  To determine whether the apparent diffusion coefficient (ADC) obtained using b = 2000 s/mm(2) upon 3 Tesla (T) diffusion-weighted MRI is superior to b = 1000 s/mm(2) for discriminating malignant from normal prostate tissue and predicting the aggressiveness of prostate cancer, using histopathological findings of radical prostatectomy as a reference.
  
  
  METHODS
  Eighty prostate cancer patients underwent preoperative 3T MRI including diffusion weighted imaging with b-values of 0, 1000, and 2000 s/mm(2) . ADCs were measured for malignant lesions and normal sites on three sets of ADC maps calculated with monoexponential fitting between b = 0 and 1000, 0 and 2000, and 1000 and 2000, respectively. The relationship between the ADC and Gleason score was evaluated.
  
  
  RESULTS
  The areas under the ROC curves for b = 0,1000, b = 0,2000, and b = 1000,2000 were 0.896, 0.937, and 0.857, respectively, in the peripheral zone (PZ) and 0.877, 0.889, and 0.731, respectively, in the transition zone (TZ). The difference between b = 0,1000 and b = 0,2000 was significant in PZ (P = 0.033), but not in TZ (P = 0.84). Weak but significant negative correlations were identified between ADCs and Gleason score in both PZ and TZ cancer at b = 0,1000 and b = 0,2000 (r = -0.323 to -0.341).
  
  
  CONCLUSIONS
  For 3T MRI, ADCs using b = 0,2000 are more accurate than b = 0,1000 for diagnosing PZ cancer, and as accurate for TZ cancer.
authors.affiliation: Department of Radiology of Kobe University Graduate School of Medicine, Kobe, Japan. kazu10041976@yahoo.co.jp
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kitajima
authors.forename: Satoru
authors.initials: S
authors.lastname: Takahashi
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Ueno
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yoshikawa
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Ohno
authors.forename: Makoto
authors.initials: M
authors.lastname: Obara
authors.forename: Hideaki
authors.initials: H
authors.lastname: Miyake
authors.forename: Masato
authors.initials: M
authors.lastname: Fujisawa
authors.forename: Kazuro
authors.initials: K
authors.lastname: Sugimura
mesh_terms: D000368:Aged; D000465:Algorithms; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity