title: Prostate diffusion imaging with distortion correction.
abstract: OBJECTIVE
  Diffusion imaging in the prostate is susceptible to distortion from B0 inhomogeneity. Distortion correction in prostate imaging is not routinely performed, resulting in diffusion images without accurate localization of tumors. We performed and evaluated distortion correction for diffusion imaging in the prostate.
  
  
  METHODS
  28 patients underwent pre-operative MRI (T2, Gadolinium perfusion, diffusion at b=800 s/mm(2)). The restriction spectrum protocol parameters included b-values of 0, 800, 1500, and 4000 s/mm(2) in 30 directions for each nonzero b-value. To correct for distortion, forward and reverse trajectories were collected at b=0 s/mm(2). Distortion maps were generated to reflect the offset of the collected data versus the corrected data. Whole-mount histology was available for correlation.
  
  
  RESULTS
  Across the 27 patients evaluated (excluding one patient due to data collection error), the average root mean square distortion distance of the prostate was 3.1 mm (standard deviation, 2.2mm; and maximum distortion, 12 mm).
  
  
  CONCLUSIONS
  Improved localization of prostate cancer by MRI will allow better surgical planning, targeted biopsies and image-guided treatment therapies. Distortion distances of up to 12 mm due to standard diffusion imaging may grossly misdirect treatment decisions. Distortion correction for diffusion imaging in the prostate improves tumor localization.
authors.affiliation: Department of Radiology, University of California San Diego School of Medicine.
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Rakow-Penner
authors.affiliation: Department of Radiology, University of California San Diego School of Medicine.
authors.forename: Nathan S
authors.initials: NS
authors.lastname: White
authors.affiliation: Department of Radiology, University of California Los Angeles Geffen School of Medicine.
authors.forename: Daniel J A
authors.initials: DJA
authors.lastname: Margolis
authors.affiliation: Department of Urology, University of California San Diego School of Medicine.
authors.forename: John Kellogg
authors.initials: JK
authors.lastname: Parsons
authors.affiliation: Department of Radiology, University of California San Diego School of Medicine.
authors.forename: Natalie
authors.initials: N
authors.lastname: Schenker-Ahmed
authors.affiliation: Department of Radiology, University of California San Diego School of Medicine.
authors.forename: Joshua M
authors.initials: JM
authors.lastname: Kuperman
authors.affiliation: Department of Radiology, University of California San Diego School of Medicine.
authors.forename: Hauke
authors.initials: H
authors.lastname: Bartsch
authors.affiliation: Department of Radiology, University of California San Diego School of Medicine.
authors.forename: Hyung W
authors.initials: HW
authors.lastname: Choi
authors.affiliation: Department of Radiology, University of California San Diego School of Medicine.
authors.forename: William G
authors.initials: WG
authors.lastname: Bradley
authors.affiliation: Department of Pathology, University of California San Diego School of Medicine.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Shabaik
authors.affiliation: Department of Pathology, University of California Los Angeles Geffen School of Medicine.
authors.forename: Jiaoti
authors.initials: J
authors.lastname: Huang
authors.affiliation: Department of Urology, University of Texas Health Science Center San Antonio.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Liss
authors.affiliation: Department of Urology, University of California Los Angeles Geffen School of Medicine.
authors.forename: Leonard
authors.initials: L
authors.lastname: Marks
authors.affiliation: Department of Urology, University of California San Diego School of Medicine.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Kane
authors.affiliation: Department of Urology, University of California Los Angeles Geffen School of Medicine.
authors.forename: Robert E
authors.initials: RE
authors.lastname: Reiter
authors.affiliation: Department of Radiology, University of California Los Angeles Geffen School of Medicine.
authors.forename: Steven S
authors.initials: SS
authors.lastname: Raman
authors.affiliation: Department of Radiology, University of California San Diego School of Medicine. Electronic address: dskarow@ucsd.edu.
authors.forename: David S
authors.initials: DS
authors.lastname: Karow
authors.affiliation: Department of Radiology, University of California San Diego School of Medicine.
authors.forename: Anders M
authors.initials: AM
authors.lastname: Dale
mesh_terms: D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005682:Gadolinium; D006801:Humans; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D011467:Prostate / Q000473:pathology*; D011471:Prostatic Neoplasms / Q000473:pathology*
chemical_list: D003287:Contrast Media; D005682:Gadolinium
keywords: Diffusion-weighted imaging; Distortion correction; MRI; Prostate cancer