title: Validation of quantitative analysis of multiparametric prostate MR images for prostate cancer detection and aggressiveness assessment: a cross-imager study.
abstract: OBJECTIVE
  To validate three previously identified quantitative image features across multiparametric magnetic resonance (MR) images acquired with imagers made by two different manufacturers to differentiate prostate cancer (PC) from normal prostatic tissue and to assess cancer aggressiveness.
  
  
  METHODS
  This study was HIPAA-compliant and approved by the institutional review board. Preoperative 1.5-T multiparametric endorectal MR images of 119 PC patients (dataset A, 71 patients; dataset B, 48 patients) were analyzed, and 265 PC and normal peripheral zone regions of interests (ROIs) were identified through histologic and MR consensus review. The 10th percentile average apparent diffusion coefficient (ADC) value, average ADC value, and skewness of T2-weighted signal-intensity histogram were evaluated with area under the receiver operating characteristic curve (AUC). The image features were combined with a linear discriminant analysis classifier and evaluated both on the image dataset of each type of imager alone (leave-one-patient-out evaluation) and across the datasets (training on one dataset, testing on the other). Spearman correlation coefficient was calculated between the image features and ROI-specific Gleason scores.
  
  
  RESULTS
  AUC values of the image features combined were 0.95 ± 0.02 (standard error) and 0.88 ± 0.03 on dataset B and dataset A alone, respectively, and 0.96 ± 0.02 and 0.89 ± 0.03 when training on dataset A and testing on dataset B and vice versa, respectively. Spearman correlation coefficients between Gleason scores and the ADC features were between -0.27 and -0.34.
  
  
  CONCLUSIONS
  Consistently across images from datasets A and B, the 10th percentile ADC value, average ADC value, and T2-weighted skewness can distinguish PC from normal-tissue ROIs, and ADC features correlate moderately with ROI-specific Gleason scores.
authors.affiliation: From the Departments of Radiology (Y.P., Y.J., M.L.G., A.O.), Pathology (T.A.), and Surgery Section of Urology (S.E.E.), University of Chicago, 5841 S Maryland Ave, Chicago, IL 60637.
authors.forename: Yahui
authors.initials: Y
authors.lastname: Peng
authors.forename: Yulei
authors.initials: Y
authors.lastname: Jiang
authors.forename: Tatjana
authors.initials: T
authors.lastname: Antic
authors.forename: Maryellen L
authors.initials: ML
authors.lastname: Giger
authors.forename: Scott E
authors.initials: SE
authors.lastname: Eggener
authors.forename: Aytekin
authors.initials: A
authors.lastname: Oto
mesh_terms: D000328:Adult; D000368:Aged; D003287:Contrast Media; D019786:Gadolinium DTPA; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D012189:Retrospective Studies
chemical_list: D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA