title: Optimal high b-value for diffusion weighted MRI in diagnosing high risk prostate cancers in the peripheral zone.
abstract: To retrospectively determine the optimal b-value(s) of diffusion-weighted imaging (DWI) associated with intermediate-high risk cancer in the peripheral zone (PZ) of the prostate.
  
  
  
  Forty-two consecutive patients underwent multi b-value (16 evenly spaced b-values between 0 and 2000 s/mm2) DWI along with multi-parametric MRI (MP-MRI) of the prostate at 3 Tesla followed by trans-rectal ultrasound/MRI fusion guided targeted biopsy of suspicious lesions detected at MP-MRI. Computed DWI images up to a simulated b-value of 4000 s/mm2were also obtained using a pair of b-values (b = 133 and 400 or 667 or 933 s/mm2) from the multi b-value DWI. The contrast ratio of average intensity of the targeted lesions and the background PZ was determined. Receiver operator characteristic curves and the area under the curve (AUCs) were obtained for separating patients eligible for active surveillance with low risk prostate cancers from intermediate-high risk prostate cancers as per the cancer of the prostate risk assessment (CAPRA) scoring system.
  
  
  
  The AUC first increased then decreased with the increase in b-values reaching maximum at b = 1600 s/mm2(0.74) with no statistically significant different AUC of DWI with b-values 1067-2000 s/mm2. The AUC of computed DWI increased then decreased with the increase in b-values reaching a maximum of 0.75 around b = 2000 s/mm2. There was no statistically significant difference between the AUC of optimal acquired DWI and either of optimal computed DWI.
  
  
  
  The optimal b-value for acquired DWI in differentiating intermediate-high from low risk prostate cancers in the PZ is b = 1600 s/mm2. The computed DWI has similar performance as that of acquired DWI with the optimal performance around b = 2000 s/mm2.
  
  
  
  4 J. Magn. Reson. Imaging 2017;45:125-131.
authors.affiliation: Molecular Imaging Program, NCI, NIH, Bethesda, Maryland, USA.|Philips Research North America, Cambridge, Massachusetts, USA.
authors.forename: Harsh K
authors.initials: HK
authors.lastname: Agarwal
authors.affiliation: Molecular Imaging Program, NCI, NIH, Bethesda, Maryland, USA.
authors.forename: Francesca V
authors.initials: FV
authors.lastname: Mertan
authors.affiliation: Molecular Imaging Program, NCI, NIH, Bethesda, Maryland, USA.
authors.forename: Sandeep
authors.initials: S
authors.lastname: Sankineni
authors.affiliation: Molecular Imaging Program, NCI, NIH, Bethesda, Maryland, USA.|Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Maryland, USA.
authors.forename: Marcelino
authors.initials: M
authors.lastname: Bernardo
authors.affiliation: Philips Research Laboratories, Hamburg, Germany.
authors.forename: Julien
authors.initials: J
authors.lastname: Senegas
authors.affiliation: Philips Research Laboratories, Hamburg, Germany.
authors.forename: Jochen
authors.initials: J
authors.lastname: Keupp
authors.affiliation: Molecular Imaging Program, NCI, NIH, Bethesda, Maryland, USA.|Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Maryland, USA.
authors.forename: Dagane
authors.initials: D
authors.lastname: Daar
authors.affiliation: Laboratory of Pathology, NCI, NIH, Bethesda, Maryland, USA.
authors.forename: Maria
authors.initials: M
authors.lastname: Merino
authors.affiliation: Center for Interventional Oncology, NCI and Radiology and Imaging Sciences, Clinical Center, NIH, Bethesda, Maryland, USA.
authors.forename: Bradford J
authors.initials: BJ
authors.lastname: Wood
authors.affiliation: Urologic Oncology Branch, NCI, NIH, Bethesda, Maryland, USA.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Pinto
authors.affiliation: Molecular Imaging Program, NCI, NIH, Bethesda, Maryland, USA.
authors.forename: Peter L
authors.initials: PL
authors.lastname: Choyke
authors.affiliation: Molecular Imaging Program, NCI, NIH, Bethesda, Maryland, USA.
authors.forename: Baris
authors.initials: B
authors.lastname: Turkbey
mesh_terms: D000328:Adult; 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; D009367:Neoplasm Staging; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity
keywords: DWI; high b-value; prostate cancer