title: Novel technique for characterizing prostate cancer utilizing MRI restriction spectrum imaging: proof of principle and initial clinical experience with extraprostatic extension.
abstract: BACKGROUND
  Standard magnetic resonance imaging (MRI) of the prostate lacks sensitivity in the diagnosis and staging of prostate cancer (PCa). To improve the operating characteristics of prostate MRI in the detection and characterization of PCa, we developed a novel, enhanced MRI diffusion technique using restriction spectrum imaging (RSI-MRI).
  
  
  METHODS
  We compared the efficacy of our novel RSI-MRI technique with standard MRI for detecting extraprostatic extension (EPE) among 28 PCa patients who underwent MRI and RSI-MRI prior to radical prostatectomy, 10 with histologically proven pT3 disease. RSI cellularity maps isolating the restricted isotropic water fraction were reconstructed based on all b-values and then standardized across the sample with z-score maps. Distortion correction of the RSI maps was performed using the alternating phase-encode technique.
  
  
  RESULTS
  27 patients were evaluated, excluding one patient where distortion could not be performed. Preoperative standard MRI correctly identified extraprostatic the extension in two of the nine pT3 (22%) patients, whereas RSI-MRI identified EPE in eight of nine (89%) patients. RSI-MRI correctly identified pT2 disease in the remaining 18 patients.
  
  
  CONCLUSIONS
  In this proof of principle study, we conclude that our novel RSI-MRI technology is feasible and shows promise for substantially improving PCa imaging. Further translational studies of prostate RSI-MRI in the diagnosis and staging of PCa are indicated.
authors.affiliation: Department of Radiology, School of Medicine, University of California San Diego, La Jolla, CA, USA.
authors.forename: R A
authors.initials: RA
authors.lastname: Rakow-Penner
authors.affiliation: Department of Radiology, School of Medicine, University of California San Diego, La Jolla, CA, USA.
authors.forename: N S
authors.initials: NS
authors.lastname: White
authors.affiliation: Department of Urology, School of Medicine, University of California San Diego, La Jolla, CA, USA.
authors.forename: J K
authors.initials: JK
authors.lastname: Parsons
authors.affiliation: Department of Radiology, School of Medicine, University of California San Diego, La Jolla, CA, USA.
authors.forename: H W
authors.initials: HW
authors.lastname: Choi
authors.affiliation: Department of Urology, School of Medicine, University of California San Diego, La Jolla, CA, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Liss
authors.affiliation: Department of Radiology, School of Medicine, University of California San Diego, La Jolla, CA, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Kuperman
authors.affiliation: Department of Radiology, School of Medicine, University of California San Diego, La Jolla, CA, USA.
authors.forename: N
authors.initials: N
authors.lastname: Schenker-Ahmed
authors.affiliation: Department of Radiology, School of Medicine, University of California San Diego, La Jolla, CA, USA.
authors.forename: H
authors.initials: H
authors.lastname: Bartsch
authors.affiliation: Department of Radiology, School of Medicine, University of California San Diego, La Jolla, CA, USA.
authors.forename: R F
authors.initials: RF
authors.lastname: Mattrey
authors.affiliation: Department of Radiology, School of Medicine, University of California San Diego, La Jolla, CA, USA.
authors.forename: W G
authors.initials: WG
authors.lastname: Bradley
authors.affiliation: Department of Pathology, School of Medicine, University of California San Diego, La Jolla, CA, USA.
authors.forename: A
authors.initials: A
authors.lastname: Shabaik
authors.affiliation: Department of Pathology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA.
authors.forename: J
authors.initials: J
authors.lastname: Huang
authors.affiliation: Department of Radiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA.
authors.forename: D J A
authors.initials: DJ
authors.lastname: Margolis
authors.affiliation: Department of Radiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA.
authors.forename: S S
authors.initials: SS
authors.lastname: Raman
authors.affiliation: Department of Urology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA.
authors.forename: L
authors.initials: L
authors.lastname: Marks
authors.affiliation: Department of Urology, School of Medicine, University of California San Diego, La Jolla, CA, USA.
authors.forename: C J
authors.initials: CJ
authors.lastname: Kane
authors.affiliation: Department of Urology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA.
authors.forename: R E
authors.initials: RE
authors.lastname: Reiter
authors.affiliation: Department of Radiology, School of Medicine, University of California San Diego, La Jolla, CA, USA.
authors.forename: D S
authors.initials: DS
authors.lastname: Karow
authors.affiliation: Department of Radiology, School of Medicine, University of California San Diego, La Jolla, CA, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Dale
mesh_terms: D000368:Aged; D005682:Gadolinium; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011467:Prostate / Q000000981:diagnostic imaging* / Q000473:pathology; D017430:Prostate-Specific Antigen; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D011859:Radiography
chemical_list: D005682:Gadolinium; D017430:Prostate-Specific Antigen