title: Biexponential apparent diffusion coefficients values in the prostate: comparison among normal tissue, prostate cancer, benign prostatic hyperplasia and prostatitis.
abstract: OBJECTIVE
  To investigate the biexponential apparent diffusion parameters of diverse prostate tissues and compare them with monoexponential apparent diffusion coefficient (ADC) value in the efficacy to discriminate prostate cancer from benign lesions.
  
  
  METHODS
  Eleven healthy volunteers and 61 patients underwent a conventional (b-factors 0, 1000 s/mm(2)) and a 10 b-factor (0 to 3000 s/mm(2)) diffusion-weighted imaging (DWI). The monoexponential ADC value and biexponential parameters of fast ADC (ADCf), fraction of ADCf (f), slow ADC (ADCs) value for 29 prostate cancer, 28 benign prostatic hyperplasia (BPH), 24 prostatitis lesions and normal tissue were calculated and compared. Receiver operating characteristic analysis was performed to determine the sensitivity, specificity and optimal cut-off points.
  
  
  RESULTS
  Prostate cancer had lower ADC, ADCf, f, and ADCs than all other tissues (p < 0.01). Prostatitis exhibited a lower ADC, ADCf, ADCs and f than the peripheral zone tissue (p < 0.01), and BPH showed a lower ADC and ADCf than the central gland tissue (p < 0.01). The ADCf demonstrated a comparable accuracy with ADC in differentiating cancer from BPH [area under the curve (AUC) 0.93 vs. 0.92] and prostatitis AUC 0.98 vs. 0.99) (both p > 0.05), but the AUC of f and ADCs in differentiating cancer from BPH (0.73 and 0.81) and prostatitis (0.88 and 0.91) were significantly lower than ADC (all p < 0.05).
  
  
  CONCLUSIONS
  The biexponential DWI appears to provide additional parameters for tissue characterization in prostate, and ADCf helps to yield comparable accuracy with ADC in differentiating cancer from benign lesions.
authors.affiliation: Department of Radiology, Fudan University Shanghai Cancer Center, Shanghai 200032, China.
authors.forename: Xiaohang
authors.initials: X
authors.lastname: Liu
authors.forename: Weijun
authors.initials: W
authors.lastname: Peng
authors.forename: Liangping
authors.initials: L
authors.lastname: Zhou
authors.forename: He
authors.initials: H
authors.lastname: Wang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001706:Biopsy; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D017430:Prostate-Specific Antigen / Q000097:blood; D011468:Prostatectomy; D011470:Prostatic Hyperplasia / Q000175:diagnosis*; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000601:surgery; D011472:Prostatitis / Q000175:diagnosis*; D012372:ROC Curve; D012680:Sensitivity and Specificity
chemical_list: D017430:Prostate-Specific Antigen
keywords: Biexponential decay; Diffusion weighted imaging; Magnetic resonance imaging; Prostate