title: Diffusion anisotropy in fresh and fixed prostate tissue ex vivo.
abstract: To investigate diffusion anisotropy in whole human prostate specimens
  
  
  
  Seven whole radical prostatectomy specimens were obtained with informed patient consent and institutional ethics approval. Diffusion tensor imaging was performed at 9.4 Tesla. Diffusion tensors were calculated from the native acquired data and after progressive downsampling
  
  
  
  Fractional anisotropy (FA) decreased as voxel volume increased, and differed widely between prostates. Fixation decreased mean FA by ∼0.05-0.08 at all voxel volumes but did not alter principle eigenvector orientation. In unfixed tissue high FA (> 0.6) was found only in voxels of volume <0.5 mm(3) , and then only in a small fraction of all voxels. At typical clinical voxel volumes (4-16 mm(3) ) less than 50% of voxels had FA > 0.25. FA decreased at longer diffusion times (Δ = 60 or 80 ms compared with 20 ms), but only by ∼0.02 at typical clinical voxel volume. Peripheral zone FA was significantly lower than transition zone FA in five of the seven prostates
  
  
  
  FA varies widely between prostates. The very small proportion of clinical size voxels with high FA suggests that in clinical DWI studies ADC based on three-direction measurements will be minimally affected by anisotropy. Magn Reson Med 76:626-634, 2016. © 2015 Wiley Periodicals, Inc.
authors.affiliation: University of Sydney, Sydney, Australia.
authors.forename: Roger M
authors.initials: RM
authors.lastname: Bourne
authors.affiliation: University of New South Wales, Sydney, Australia.
authors.forename: Andre
authors.initials: A
authors.lastname: Bongers
authors.affiliation: University of Sydney, Sydney, Australia.
authors.forename: Aritrick
authors.initials: A
authors.lastname: Chatterjee
authors.affiliation: University of Sydney and Royal Prince Alfred Hospital, Sydney, Australia.
authors.forename: Paul
authors.initials: P
authors.lastname: Sved
authors.affiliation: Royal Prince Alfred Hospital, Sydney, Australia.
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Watson
mesh_terms: D000368:Aged; D016880:Anisotropy; D016477:Artifacts; D004058:Diffusion; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D011467:Prostate / Q000000981:diagnostic imaging* / Q000473:pathology*; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D059629:Signal-To-Noise Ratio
keywords: diffusion tensor imaging; diffusion weighted imaging; fractional anisotropy; prostate