title: Prostate cancer: prediction of extracapsular extension with endorectal MR imaging and three-dimensional proton MR spectroscopic imaging.
abstract: OBJECTIVE
  To determine if the addition of three-dimensional (3D) proton magnetic resonance (MR) spectroscopic imaging to endorectal MR imaging helps diagnose extracapsular extension (ECE) of prostate cancer.
  
  
  METHODS
  Endorectal MR imaging and 3D MR spectroscopic imaging were performed in 53 patients with prostate cancer before radical prostatectomy. MR imaging studies were evaluated by two independent readers unaware of histopathologic findings. The presence of ECE was graded on a five-point scale. At 3D MR spectroscopic imaging, cancer was diagnosed if the ratio of choline plus creatine to citrate was 2 or more SDs above normal. The accuracy of MR imaging alone was compared with that of combined MR imaging and 3D MR spectroscopic imaging, with use of the step-section histopathologic results as the standard of reference.
  
  
  RESULTS
  For the less experienced reader, the addition of 3D MR spectroscopic imaging to MR imaging significantly improved accuracy (area under the receiver operating characteristic curve [Az] = 0.75 vs Az = 0.62, P < .05). For the more experienced reader, the addition improved accuracy but not significantly (Az = 0.86 vs Az = 0.78). The addition also reduced interobserver variability (Az = 0.86 vs Az = 0.75).
  
  
  CONCLUSIONS
  The addition of 3D MR spectroscopic imaging to MR imaging improves accuracy for less experienced readers and reduces interobserver variability in the diagnosis of ECE of prostate cancer.
authors.affiliation: Department of Radiology, University of California at San Francisco 94143-0628, USA.
authors.forename: K K
authors.initials: KK
authors.lastname: Yu
authors.forename: J
authors.initials: J
authors.lastname: Scheidler
authors.forename: H
authors.initials: H
authors.lastname: Hricak
authors.forename: D B
authors.initials: DB
authors.lastname: Vigneron
authors.forename: C J
authors.initials: CJ
authors.lastname: Zaloudek
authors.forename: R G
authors.initials: RG
authors.lastname: Males
authors.forename: S J
authors.initials: SJ
authors.lastname: Nelson
authors.forename: P R
authors.initials: PR
authors.lastname: Carroll
authors.forename: J
authors.initials: J
authors.lastname: Kurhanewicz
mesh_terms: D003430:Cross-Sectional Studies; D018450:Disease Progression; D006801:Humans; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D011237:Predictive Value of Tests; D011471:Prostatic Neoplasms / Q000473:pathology*; D012007:Rectum; D012189:Retrospective Studies; D012680:Sensitivity and Specificity