title: Prostate volume estimations using magnetic resonance imaging and transrectal ultrasound compared to radical prostatectomy specimens.
abstract: BACKGROUND
  We sought to evaluate the accuracy of prostate volume estimates in patients who received both a preoperative transrectal ultrasound (TRUS) and magnetic resonance imaging (MRI) in relation to the referent pathological specimen post-radical prostatectomy.
  
  
  METHODS
  Patients receiving both TRUS and MRI prior to radical prostatectomy at one academic institution were retrospectively analyzed. TRUS and MRI volumes were estimated using the prolate ellipsoid formula. TRUS volumes were collected from sonography reports. MRI volumes were estimated by two blinded raters and the mean of the two was used for analyses. Pathological volume was calculated using a standard fluid displacement method.
  
  
  RESULTS
  Three hundred and eighteen (318) patients were included in the analysis. MRI was slightly more accurate than TRUS based on interclass correlation (0.83 vs. 0.74) and absolute risk bias (higher proportion of estimates within 5, 10, and 20 cc of pathological volume). For TRUS, 87 of 298 (29.2%) prostates without median lobes differed by >10 cc of specimen volume and 22 of 298 (7.4%) differed by >20 cc. For MRI, 68 of 298 (22.8%) prostates without median lobes differed by >10 cc of specimen volume, while only 4 of 298 (1.3%) differed by >20 cc.
  
  
  CONCLUSIONS
  MRI and TRUS prostate volume estimates are consistent with pathological volumes along the prostate size spectrum. MRI demonstrated better correlation with prostatectomy specimen volume in most patients and may be better suited in cases where TRUS and MRI estimates are disparate. Validation of these findings with prospective, standardized ultrasound techniques would be helpful.
authors.affiliation: Division of Urology, Department of Surgery, The Ottawa Hospital, University of Ottawa, Ottawa, ON, Canada.
authors.forename: Nicholas R
authors.initials: NR
authors.lastname: Paterson
authors.affiliation: Division of Urology, Department of Surgery, The Ottawa Hospital, University of Ottawa, Ottawa, ON, Canada;; Ottawa Hospital Research Institute, Department of Clinical Epidemiology, Ottawa, ON, Canada.
authors.forename: Luke T
authors.initials: LT
authors.lastname: Lavallée
authors.affiliation: Division of Urology, Department of Surgery, The Ottawa Hospital, University of Ottawa, Ottawa, ON, Canada.
authors.forename: Laura N
authors.initials: LN
authors.lastname: Nguyen
authors.affiliation: Ottawa Hospital Research Institute, Department of Clinical Epidemiology, Ottawa, ON, Canada.
authors.forename: Kelsey
authors.initials: K
authors.lastname: Witiuk
authors.affiliation: Division of Urology, Department of Surgery, The Ottawa Hospital, University of Ottawa, Ottawa, ON, Canada.
authors.forename: James
authors.initials: J
authors.lastname: Ross
authors.affiliation: Ottawa Hospital Research Institute, Department of Clinical Epidemiology, Ottawa, ON, Canada.
authors.forename: Ranjeeta
authors.initials: R
authors.lastname: Mallick
authors.affiliation: Department of Radiology, The Ottawa Hospital, University of Ottawa, Ottawa, ON, Canada.
authors.forename: Wael
authors.initials: W
authors.lastname: Shabana
authors.affiliation: Department of Radiology, The Ottawa Hospital, University of Ottawa, Ottawa, ON, Canada.
authors.forename: Blair
authors.initials: B
authors.lastname: MacDonald
authors.affiliation: Department of Radiology, The Ottawa Hospital, University of Ottawa, Ottawa, ON, Canada.
authors.forename: Nicola
authors.initials: N
authors.lastname: Scheida
authors.affiliation: Ottawa Hospital Research Institute, Department of Clinical Epidemiology, Ottawa, ON, Canada.
authors.forename: Dean
authors.initials: D
authors.lastname: Fergusson
authors.affiliation: Ottawa Hospital Research Institute, Department of Clinical Epidemiology, Ottawa, ON, Canada.
authors.forename: Franco
authors.initials: F
authors.lastname: Momoli
authors.affiliation: Ottawa Hospital Research Institute, Department of Clinical Epidemiology, Ottawa, ON, Canada.
authors.forename: Sonya
authors.initials: S
authors.lastname: Cnossen
authors.affiliation: Division of Urology, Department of Surgery, The Ottawa Hospital, University of Ottawa, Ottawa, ON, Canada.
authors.forename: Christopher
authors.initials: C
authors.lastname: Morash
authors.affiliation: Division of Urology, Department of Surgery, The Ottawa Hospital, University of Ottawa, Ottawa, ON, Canada.
authors.forename: Ilias
authors.initials: I
authors.lastname: Cagiannos
authors.affiliation: Division of Urology, Department of Surgery, The Ottawa Hospital, University of Ottawa, Ottawa, ON, Canada;; Ottawa Hospital Research Institute, Department of Clinical Epidemiology, Ottawa, ON, Canada.
authors.forename: Rodney H
authors.initials: RH
authors.lastname: Breau