title: Prostate cancer: multiparametric MRI for index lesion localization--a multiple-reader study.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the utility of multiparametric MRI in localization of the index lesion of prostate cancer.
  
  
  METHODS
  Fifty-one patients who underwent 3-T MRI of the prostate with a pelvic phased-array coil that included T2-weighted, diffusion-weighted, and dynamic contrast-enhanced sequences before prostatectomy were included. Six radiologists assessed all images to identify the lesion most suspicious of being the index lesion, which was localized to one of 18 regions. A uropathologist using the same 18-region scheme reviewed the prostatectomy slides to localize the index lesion. MRI performance was assessed by requiring either an exact match or an approximate match (discrepancy of up to one region) between the MRI and pathologic findings in terms of assigned region.
  
  
  RESULTS
  The pathologist identified an index lesion in 49 of 51 patients. In exact-match analysis, the average sensitivity was 60.2% (range, 51.0-63.3%), and the average positive predictive value (PPV) was 65.3% (range, 61.2-69.4%). In approximate-match analysis, the average sensitivity was 75.9% (range, 65.3-69.6%), and the average PPV was 82.6% (range, 79.2-91.4%). The sensitivity was higher for index lesions with a Gleason score greater than 6 in exact-match (74.8% vs 15.3%, p<0.001) and approximate-match (88.7% vs 36.1%, p=<0.001) analyses and for index lesions measuring at least 1 cm in approximate-match analysis (80.3% vs 58.3%, p=0.016). In exact-match analysis, 30.0%, 44.9%, and 79.1% of abnormalities found with one, two, and three MRI parameters represented the index lesion (p<0.001).
  
  
  CONCLUSIONS
  The sensitivity and PPV of multiparametric MRI for index lesion localization were moderate, although they improved in the setting of more aggressive pathologic features and a greater number of abnormal MRI parameters, respectively.
authors.affiliation: Department of Radiology, New York University School of Medicine, Langone Medical Center, 560 First Ave, TCH-HW202, New York, NY 10016, USA. Andrew.Rosenkrantz@nyumc.org
authors.forename: Andrew B
authors.initials: AB
authors.lastname: Rosenkrantz
authors.forename: Fang-Ming
authors.initials: FM
authors.lastname: Deng
authors.forename: Sooah
authors.initials: S
authors.lastname: Kim
authors.forename: Ruth P
authors.initials: RP
authors.lastname: Lim
authors.forename: Nicole
authors.initials: N
authors.lastname: Hindman
authors.forename: Thais C
authors.initials: TC
authors.lastname: Mussi
authors.forename: Bradley
authors.initials: B
authors.lastname: Spieler
authors.forename: Jason
authors.initials: J
authors.lastname: Oaks
authors.forename: James S
authors.initials: JS
authors.lastname: Babb
authors.forename: Jonathan
authors.initials: J
authors.lastname: Melamed
authors.forename: Samir S
authors.initials: SS
authors.lastname: Taneja
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000473:pathology; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media