title: Efficacy of using three-tesla magnetic resonance imaging diagnosis of capsule invasion for decision-making about neurovascular bundle preservation in robotic-assisted radical prostatectomy.
abstract: OBJECTIVE
  To evaluate the efficacy of using 3-tesla (T) magnetic resonance imaging (MRI) diagnosis of extracapsular extension (ECE) for decision-making about neurovascular bundle (NVB) preservation in robot-assisted radical prostatectomy (RARP) for prostate cancer (PC).
  
  
  METHODS
  We prospectively collected data on PC patients (n=67) who underwent preoperative 3-T MRI before RARP. The choice between nerve sparing or resection was based on 3-T MRI findings of ECE. We compared the MRI findings with the pathological data on surgical margins. Our clinical staging in this study was defined only by MRI.
  
  
  RESULTS
  When the data were divided by prostate lobe (right lobe or left lobe, n=134), 3-T MRI showed 28 positive cases of ECE in 134 prostate lobes, allowing NVB preservation in 42 cases (31.3%). Nerve-sparing surgery was achieved in 38.7% of cases in which clinical T2 staging by MRI was reported. The pathological data revealed that 10 of 134 prostate lobes had positive ECE. The overall sensitivity, specificity, positive predictive value, and negative predictive value for predicting stage T3 (positive ECE) by side were 60.0% (12 of 20 sides), 86.0% (98 of 114 sides), 42.9% (12 of 28 sides), and 92.5% (98 of 106 sides), respectively.
  
  
  CONCLUSIONS
  Three-T MRI prior to RARP enables the use of ECE diagnosis to guide decision-making about NVB preservation, with comparatively high specificity and negative predictive value. Further prospective studies are underway to reach more definitive conclusions.
authors.affiliation: Division of Urology, Department of Surgery Related, Kobe University Graduate School of Medicine, Kobe, Japan.
authors.forename: Kazushi
authors.initials: K
authors.lastname: Tanaka
authors.forename: Katsumi
authors.initials: K
authors.lastname: Shigemura
authors.forename: Mototsugu
authors.initials: M
authors.lastname: Muramaki
authors.forename: Satoru
authors.initials: S
authors.lastname: Takahashi
authors.forename: Hideaki
authors.initials: H
authors.lastname: Miyake
authors.forename: Masato
authors.initials: M
authors.lastname: Fujisawa
keywords: Diagnoses; Magnetic resonance imaging; Prostatectomy; Robotics