title: Accuracy and agreement of PIRADSv2 for prostate cancer mpMRI: A multireader study.
abstract: Multiparametric MRI (mpMRI) improves the detection of clinically significant prostate cancer, but is limited by interobserver variation. The second version of theProstate Imaging Reporting and Data System (PIRADSv2) was recently proposed as a standard for interpreting mpMRI. To assess the performance and interobserver agreement of PIRADSv2 we performed a multi-reader study with five radiologists of varying experience.
  
  
  
  Five radiologists (n = 2 prostate dedicated, n = 3 general body) blinded to clinicopathologic results detected and scored lesions on prostate mpMRI using PIRADSv2. The endorectal coil 3 Tesla MRI included T2W, diffusion-weighted imaging (apparent diffusion coefficient, b2000), and dynamic contrast enhancement. Thirty-four consecutive patients were included. Results were correlated with radical prostatectomy whole-mount histopathology produced with patient-specific three-dimensional molds. An index lesion was defined on pathology as the lesion with highest Gleason score or largest volume if equivalent grades. Average sensitivity and positive predictive values (PPVs) for all lesions and index lesions were determined using generalized estimating equations. Interobserver agreement was evaluated using index of specific agreement.
  
  
  
  Average sensitivity was 91% for detecting index lesions and 63% for all lesions across all readers. PPV was 85% for PIRADS ≥ 3 and 90% for PIRADS ≥ 4. Specialists performed better only for PIRADS ≥ 4 with sensitivity 90% versus 79% (P = 0.01) for index lesions. Index of specific agreement among readers was 93% for the detection of index lesions, 74% for the detection of all lesions, and 85% for scoring index lesions, and 58% for scoring all lesions.
  
  
  
  By using PIRADSv2, general body radiologists and prostate specialists can detect high-grade index prostate cancer lesions with high sensitivity and agreement.
  
  
  
  1 J. Magn. Reson. Imaging 2017;45:579-585.
authors.affiliation: Molecular Imaging Program, NCI, NIH, Bethesda, Maryland, USA.|Cleveland Clinic Lerner College of Medicine, Cleveland, Ohio, USA.
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Greer
authors.affiliation: Molecular Imaging Program, NCI, NIH, Bethesda, Maryland, USA.|Duke University School of Medicine, Durham, North Carolina, USA.
authors.forename: Anna M
authors.initials: AM
authors.lastname: Brown
authors.affiliation: Biometric Research Program, NCI, NIH, Bethesda, Maryland, USA.
authors.forename: Joanna H
authors.initials: JH
authors.lastname: Shih
authors.affiliation: National Institutes of Health Clinical Center, Imaging Biomarkers and Computer-Aided Diagnosis Laboratory, Radiology and Imaging Sciences, Bethesda, Maryland, USA.
authors.forename: Ronald M
authors.initials: RM
authors.lastname: Summers
authors.affiliation: Walter Reed National Military Medical Center, Bethesda, Maryland, USA.
authors.forename: Jamie
authors.initials: J
authors.lastname: Marko
authors.affiliation: Singapore General Hospital, Singapore.
authors.forename: Yan Mee
authors.initials: YM
authors.lastname: Law
authors.affiliation: Molecular Imaging Program, NCI, NIH, Bethesda, Maryland, USA.
authors.forename: Sandeep
authors.initials: S
authors.lastname: Sankineni
authors.affiliation: Urologic Oncology Branch, NCI, NIH, Bethesda, Maryland, USA.
authors.forename: Arvin K
authors.initials: AK
authors.lastname: George
authors.affiliation: Laboratory of Pathology, NCI, NIH, Bethesda, Maryland, USA.
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Merino
authors.affiliation: Urologic Oncology Branch, NCI, NIH, Bethesda, Maryland, USA.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Pinto
authors.affiliation: Molecular Imaging Program, NCI, NIH, Bethesda, Maryland, USA.
authors.forename: Peter L
authors.initials: PL
authors.lastname: Choyke
authors.affiliation: Molecular Imaging Program, NCI, NIH, Bethesda, Maryland, USA.
authors.forename: Baris
authors.initials: B
authors.lastname: Turkbey
mesh_terms: D038524:Diffusion Magnetic Resonance Imaging / Q000592:standards*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000592:standards*; D008297:Male; D015588:Observer Variation; D017410:Practice Guidelines as Topic; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D011871:Radiology / Q000592:standards*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014481:United States
keywords: PIRADSv2; inter-observer agreement; multi-reader study; prostate cancer; prostate mpMRI