title: Prostate cancer: correlation of intravoxel incoherent motion MR parameters with Gleason score.
abstract: OBJECTIVE
  To evaluate the potential of intravoxel incoherent motion (IVIM) imaging to predict histological prognostic parameters by investigating whether IVIM parameters correlate with Gleason score.
  
  
  METHODS
  The institutional review board approved this retrospective study, and informed consent was waived. A total of 41 patients with histologically proven prostate cancer who underwent prostate MRI using a 3T MRI machine were included. For eight diffusion-weighted imaging b-values (0, 10, 20, 50, 100, 200, 500, and 800s/mm(2)), a spin-echo echo-planar imaging sequence was performed. D, f, D(⁎), and ADCfit values were compared among three groups of patients with prostate cancer: Gleason score 6 (n=9), 7 (n=16), or 8 or higher (n=16). Receiver operating characteristic (ROC) curves were generated for D, f, D(⁎), and ADCfit to assess the ability of each parameter to distinguish cancers with low Gleason scores from cancers with intermediate or high Gleason scores.
  
  
  RESULTS
  Pearson's coefficient analysis revealed significant negative correlations between Gleason score and ADCfit (r=-0.490, P=.001) and Gleason score and D values (r=-0.514, P=.001). Gleason score was poorly correlated with f (r=0.168, P=.292) and D(⁎) values (r=-0.108, P=.500). The ADCfit and D values of prostate cancers with Gleason scores 7 or ≥8 were significantly lower than values for prostate cancers with Gleason score 6 (P<.05). ROC curves were constructed to assess the ability of IVIM parameters to discriminate prostate cancers with Gleason score 6 from cancers with Gleason scores 7 or ≥8. Areas under the curve were 0.671 to 0.974. ADCfit and D yielded the highest Az value (0.960-0.956), whereas f yielded the lowest Az value (0.633).
  
  
  CONCLUSIONS
  The pure molecular diffusion parameter, D, was the IVIM parameter that best discriminated prostate cancers with low Gleason scores from prostate cancers with intermediate or high Gleason scores.
authors.affiliation: Department of Radiology, Kyung Hee University Hospital at Gangdong, Seoul, Republic of Korea. Electronic address: dmy2988@daum.net.
authors.forename: Dal Mo
authors.initials: DM
authors.lastname: Yang
authors.affiliation: Department of Radiology, Kyung Hee University Hospital at Gangdong, Seoul, Republic of Korea.
authors.forename: Hyun Cheol
authors.initials: HC
authors.lastname: Kim
authors.affiliation: Department of Radiology, Kyung Hee University Hospital at Gangdong, Seoul, Republic of Korea.
authors.forename: Sang Won
authors.initials: SW
authors.lastname: Kim
authors.affiliation: Department of Radiology, Kyung Hee University Hospital at Gangdong, Seoul, Republic of Korea.
authors.forename: Geon-Ho
authors.initials: GH
authors.lastname: Jahng
authors.affiliation: Department of Pathology, Kyung Hee University Hospital at Gangdong, Seoul, Republic of Korea.
authors.forename: Kyu Yeoun
authors.initials: KY
authors.lastname: Won
authors.affiliation: Department of Pathology, Kyung Hee University Hospital at Gangdong, Seoul, Republic of Korea.
authors.forename: Sung Jig
authors.initials: SJ
authors.lastname: Lim
authors.affiliation: Department of Biomedical Engineering, College of Electronics and Information, Kyung Hee University, Yongin, Republic of Korea.
authors.forename: Jang-Hoon
authors.initials: JH
authors.lastname: Oh
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D017352:Echo-Planar Imaging / Q000379:methods*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009038:Motion; D060787:Neoplasm Grading / Q000379:methods*; D011467:Prostate / Q000000981:diagnostic imaging / Q000473:pathology*; D011471:Prostatic Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000473:pathology; D012372:ROC Curve; D012189:Retrospective Studies
keywords: Diffusion-weighted imaging; Incoherent intravoxel motion MRI; Magnetic resonance imaging; Prostate; Prostate cancer