title: Evaluation of apparent diffusion coefficient and MR volumetry as independent associative factors for extra-prostatic extension (EPE) in prostatic carcinoma.
abstract: BACKGROUND
  To assess mean apparent diffusion coefficient (ADC) and MR-derived tumor volume (Vt) as associative factors for extra-prostatic extension (EPE) in prostate cancer (PCa).
  
  
  METHODS
  With institutional review board approval, 73 consecutive patients diagnosed with PCa at trans-rectal ultrasound biopsy underwent preoperative multi-parametric (T2W+DWI+DCE) 3 Tesla MRI before radical prostatectomy between 2012 and 2014; 52% (38/73) patients had EPE. Clinical parameters including: age, prostate serum antigen (PSA), digital rectal examination (DRE) and percentage positive cores (PPC) were recorded. Two blinded radiologists subjectively evaluated for EPE using PI-RADS with T2W-MRI. A third blinded radiologist recorded: mean ADC (mm(2) /s) of tumor and tumor volume on ADC and T2W (derived from planar volumetry). VtMAX (the largest volume on ADC or T2W) was documented. Multivariate and receiver operator characteristic analyses were performed.
  
  
  RESULTS
  There were no significant differences in age, DRE, or Gleason score between groups (P = 0.52, 0.06, 0.61, 0.36). PSA approached significance being higher with EPE (12.9 ± 12.6 versus 8.2 ± 7.4; P = 0.06). PPC was higher with EPE (60.9 ± 21.9% versus 38.3 ± 21.6%; P < 0.01) with an area under the curve (AUC) of 0.78 and sensitivity/specificity = 75.7/75% when PPC ≥ 45%. AUC for T2W-MRI was 0.46-0.51 with sensitivity/specificity = 40.0-42.9/48.6-57.1% (R1, R2). Inter-observer agreement was fair, k = 0.39. There was no difference in mean ADC between groups (0.89 ± 0.25 versus 0.88 ± 0.19 [EPE] mm(2) /s), P = 0.70. T2W-Vt, ADC-Vt, and VtMAX were larger with EPE (5.1 ± 7.4, 5.8 ± 6.5, 6.3 ± 7.4 cm(3) versus 1.6 ± 1.8, 1.8 ± 1.3, 2.1 ± 1.8), P < 0.01. VtMAX AUC was 0.77 with sensitivity/specificity = 78.4/73.5% when VtMAX  ≥ 2.1 cm(3) which outperformed all other parameters (P > 0.05) except PPC (P = 0.6) for the diagnosis EPE.
  
  
  CONCLUSIONS
  MR volumetry and percentage of positive core biopsies are associated with EPE; whereas, in this study, other clinical and MR parameters including mean ADC and subjective T2W-MR analysis were not useful for assessment of EPE.
authors: The Ottawa Hospital, The University of Ottawa Department of Radiology, Civic Campus C1, Ottawa, Ontario, Canada.
authors: Christopher
authors: C
authors: Lim
authors: The Ottawa Hospital, The University of Ottawa Department of Anatomical Pathology, Ottawa, Ontario, Canada.
authors: Trevor A
authors: TA
authors: Flood
authors: The Ottawa Hospital, The University of Ottawa Department of Anatomical Pathology, Ottawa, Ontario, Canada.
authors: Shaheed W
authors: SW
authors: Hakim
authors: The Ottawa Hospital, The University of Ottawa Department of Radiology, Civic Campus C1, Ottawa, Ontario, Canada.
authors: Wael M
authors: WM
authors: Shabana
authors: The Ottawa Hospital, The University of Ottawa Department of Radiology, Civic Campus C1, Ottawa, Ontario, Canada.
authors: Jeffrey S
authors: JS
authors: Quon
authors: The Ottawa Hospital, The University of Ottawa Department of Radiology, Civic Campus C1, Ottawa, Ontario, Canada.
authors: Mohamed
authors: M
authors: El-Khodary
authors: The Ottawa Hospital, The University of Ottawa Department of Radiology, Civic Campus C1, Ottawa, Ontario, Canada.
authors: Rebecca E
authors: RE
authors: Thornhill
authors: The Ottawa Hospital, The University of Ottawa Department of Anatomical Pathology, Ottawa, Ontario, Canada.
authors: Soufiane
authors: S
authors: El Hallani
authors: The Ottawa Hospital, The University of Ottawa Department of Radiology, Civic Campus C1, Ottawa, Ontario, Canada.
authors: Nicola
authors: N
authors: Schieda
mesh_terms: D000368:Aged; D019540:Area Under Curve; D001706:Biopsy; D002277:Carcinoma / Q000000981:diagnostic imaging* / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D060787:Neoplasm Grading; D015588:Observer Variation; D011467:Prostate / Q000473:pathology; D017430:Prostate-Specific Antigen / Q000097:blood; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D012372:ROC Curve; D011871:Radiology; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014463:Ultrasonography
chemical_list: D017430:Prostate-Specific Antigen
keywords: apparent diffusion coefficient; local staging; magnetic resonance imaging; prostate cancer; volume