title: Computed diffusion-weighted imaging of the prostate at 3 T: impact on image quality and tumour detection.
abstract: OBJECTIVE
  To investigate the impact of prostate computed diffusion-weighted imaging (DWI) on image quality and tumour detection.
  
  
  METHODS
  Forty-nine patients underwent 3-T magnetic resonance imaging using a pelvic phased-array coil before prostatectomy, including DWI with b values of 50 and 1,000 s/mm(2). Computed DW images with b value 1,500 s/mm(2) were generated from the lower b-value images. Directly acquired b-1,500 DW images were obtained in 39 patients. Two radiologists independently assessed DWI for image quality measures and location of the dominant lesion. A third radiologist measured tumour-to-peripheral-zone (PZ) contrast. Pathological findings from prostatectomy served as the reference standard.
  
  
  RESULTS
  Direct and computed b-1,500 DWI showed better suppression of benign prostate tissue than direct b-1,000 DWI for both readers (P ≤ 0.024). However, computed b-1,500 DWI showed less distortion and ghosting than direct b-1,000 and direct b-1,500 DWI for both readers (P ≤ 0.067). Direct and computed b-1,500 images showed better sensitivity and positive predictive value (PPV) for tumour detection than direct b-1,000 images for both readers (P ≤ 0.062), with no difference in sensitivity or PPV between direct and computed b-1,500 images (P ≥ 0.180). Tumour-to-PZ contrast was greater on computed b-1,500 than on either direct DWI set (P < 0.001).
  
  
  CONCLUSIONS
  Computed DWI of the prostate using b value ≥1,000 s/mm(2) improves image quality and tumour detection compared with acquired standard b-value images.
  
  
  CONCLUSIONS
  • Diffusion weighted MRI is increasingly used for diagnosing and assessing prostate carcinoma. • Prostate computed DWI can extrapolate high b-value images from lower b values. • Computed DWI provides greater suppression of benign tissue than lower b-value images. • Computed DWI provides less distortion and artefacts than images using same b value. • Computed DWI provides better diagnostic performance than lower b-value images.
authors.affiliation: Department of Radiology, NYU Langone Medical Center, 550 First Avenue, New York, NY, 10016, USA, Andrew.Rosenkrantz@nyumc.org.
authors.forename: Andrew B
authors.initials: AB
authors.lastname: Rosenkrantz
authors.forename: Hersh
authors.initials: H
authors.lastname: Chandarana
authors.forename: Nicole
authors.initials: N
authors.lastname: Hindman
authors.forename: Fang-Ming
authors.initials: FM
authors.lastname: Deng
authors.forename: James S
authors.initials: JS
authors.lastname: Babb
authors.forename: Samir S
authors.initials: SS
authors.lastname: Taneja
authors.forename: Christian
authors.initials: C
authors.lastname: Geppert
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011467:Prostate / Q000473:pathology* / Q000601:surgery; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000601:surgery; D012189:Retrospective Studies