title: Evaluation of MRI for diagnosis of extraprostatic extension in prostate cancer.
abstract: To assess the ability of magnetic resonance imaging (MRI) to diagnose extraprostatic extension (EPE) in prostate cancer.
  
  
  
  With Institutional Review Board (IRB) approval, 149 men with 170 ≥0.5 mL tumors underwent preoperative 3T MRI followed by radical prostatectomy (RP) between 2012-2015. Two blinded radiologists (R1/R2) assessed tumors using Prostate Imaging Reporting and Data System (PI-RADS) v2, subjectively evaluated for the presence of EPE, measured tumor size, and length of capsular contact (LCC). A third blinded radiologist, using MRI-RP-maps, measured whole-lesion: apparent diffusion coefficient (ADC) mean/centile and histogram features. Comparisons were performed using chi-square, logistic regression, and receiver operator characteristic (ROC) analysis.
  
  
  
  The subjective EPE assessment showed high specificity (SPEC = 75.4/91.3% [R1/R2]), low sensitivity (SENS = 43.3/43.6% [R1/R2]), and area-under (AU) ROC curve = 0.67 (confidence interval [CI] 0.61-0.73) R1 and 0.61 (CI 0.53-0.70) R2; (k = 0.33). PI-RADS v2 scores were strongly associated with EPE (P < 0.001 / P = 0.008; R1/R2) with AU-ROC curve = 0.72 (0.64-0.79) R1 and 0.61 (0.53-0.70) R2; (k = 0.44). Tumors with EPE were larger (18.8 ± 7.8 [median 17, range 6-51] vs. 18.8 ± 4.9 [12, 6-28] mm) and had greater LCC (21.1 ± 14.9 [16, 1-85] vs. 13.6 ± 6.1 [11.5, 4-30] mm); P < 0.001 and 0.002, respectively. AU-ROC for size was 0.73 (0.64-0.80) and LCC was 0.69 (0.60-0.76), respectively. Optimal SENS/SPEC for diagnosis of EPE were: size ≥15 mm = 67.7/66.7% and LCC ≥11 mm = 84.9/44.8%. 10th-centile ADC and ADC entropy were both associated with EPE (P = 0.02 and < 0.001), with AU-ROC = 0.56 (0.47-0.65) and 0.76 (0.69-0.83), respectively. Optimal SENS/SPEC for diagnosis of EPE with entropy ≥6.99 was 63.3/75.0%. 25th-centile ADC trended towards being significantly lower with EPE (P = 0.06) with no difference in other ADC metrics (P = 0.25-0.88). Size, LCC, and ADC entropy improved sensitivity but reduced specificity compared with subjective analysis with no difference in overall accuracy (P = 0.38).
  
  
  
  Measurements of tumor size, capsular contact, and ADC entropy improve sensitivity but reduce specificity for diagnosis of EPE compared to subjective assessment.
  
  
  
  3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:176-185.
authors.affiliation: Department of Medical Imaging, Ottawa Hospital, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Satheesh
authors.initials: S
authors.lastname: Krishna
authors.affiliation: Department of Medical Imaging, Ottawa Hospital, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Christopher S
authors.identifier: 0000-0003-1546-5620
authors.initials: CS
authors.lastname: Lim
authors.affiliation: Department of Medical Imaging, Ottawa Hospital, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Matthew D F
authors.initials: MDF
authors.lastname: McInnes
authors.affiliation: Department of Anatomical Pathology, Ottawa Hospital, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Trevor A
authors.initials: TA
authors.lastname: Flood
authors.affiliation: Department of Medical Imaging, Ottawa Hospital, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Wael M
authors.initials: WM
authors.lastname: Shabana
authors.affiliation: Department of Medical Imaging, Ottawa Hospital, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Lim
authors.affiliation: Department of Medical Imaging, Ottawa Hospital, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Nicola
authors.initials: N
authors.lastname: Schieda
mesh_terms: D000368:Aged; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D057234:Preoperative Period; D011467:Prostate / Q000000981:diagnostic imaging; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery; D012372:ROC Curve; D011871:Radiology; D012044:Regression Analysis; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
keywords: MRI; PI-RADS; apparent diffusion coefficient (ADC); extraprostatic extension; prostate cancer; texture analysis