title: High-resolution diffusion-weighted imaging of the prostate.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the effect of increasing the spatial resolution of the prostate DWI protocol on image quality and lesion conspicuity.
  
  
  METHODS
  Twenty-nine patients with biopsy-proven prostate cancer undergoing MRI examinations were imaged with two diffusion-weighted imaging (DWI) protocols: current standard clinical protocol (6.7 mm(3) voxels) and a new high-resolution protocol (3.1 mm(3) voxels). Diffusion-weighted images were independently and subjectively scored on lesion conspicuity, internal architecture definition, and overall image quality by two radiologists. Average apparent diffusion coefficient (ADC) values were measured in normal tissue and cancerous lesions on both sequences. Reader scores and ADC and contrast values were compared between the two protocols. Cancer ADC values were correlated with Gleason scores.
  
  
  RESULTS
  The signal-to-noise ratio of the new high-resolution DWI protocol was 40% lower than that of the standard protocol. The reader scores were higher by 0.73 (range, 0.29-1.16) grades, or 19% (range, 7-32%), on average, for the new protocol, indicating better image quality. The average ADC values were 8% higher with the new protocol, with ADC contrast values between cancer and normal prostate unchanged. There was marginally significant correlation of cancer ADC values with Gleason scores (p = 0.05, r ≈ -0.36).
  
  
  CONCLUSIONS
  We showed that for DWI of the prostate at 3-7 mm(3) voxel sizes the benefits of higher spatial resolution outweigh the effects of reduced signal-to-noise and contrast-to-noise ratios, potentially improving the sensitivity to small or sparse prostate cancers. Radiologists can consider using higher-spatial-resolution DWI sequences in their practices.
authors.affiliation: 1 Department of Radiology, University of Chicago, 5841 S Maryland Ave, MC 2026, Chicago, IL 60637.
authors.forename: Milica
authors.initials: M
authors.lastname: Medved
authors.forename: Fatma N
authors.initials: FN
authors.lastname: Soylu-Boy
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Karademir
authors.forename: Ila
authors.initials: I
authors.lastname: Sethi
authors.forename: Ambereen
authors.initials: A
authors.lastname: Yousuf
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Karczmar
authors.forename: Aytekin
authors.initials: A
authors.lastname: Oto
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D011446:Prospective Studies; D011471:Prostatic Neoplasms / Q000473:pathology*; D059629:Signal-To-Noise Ratio
keywords: MRI; high-resolution diffusion-weighted imaging (DWI); prostate cancer