title: Locally recurrent prostate cancer after high-dose-rate brachytherapy: the value of diffusion-weighted imaging, dynamic contrast-enhanced MRI, and T2-weighted imaging in localizing tumors.
abstract: OBJECTIVE
  The purpose of this article is to retrospectively evaluate the utility of prostate MRI for detecting locally recurrent prostate cancer after high-dose-rate (HDR) brachytherapy.
  
  
  METHODS
  Sixteen men with biochemical failure after HDR brachytherapy for prostate cancer underwent prostate MRI, including T2-weighted imaging, dynamic contrast-enhanced MRI (DCE-MRI), and diffusion-weighted imaging (DWI), using a 1.5-T MRI unit before 12-core-specimen biopsy. Two radiologists in consensus assessed the presence of tumor on each sequence within eight regions of the prostate (six from the peripheral zone [PZ] and two from the transition zone [TZ]) on the basis of biopsy.
  
  
  RESULTS
  Biopsy revealed locally recurrent prostate cancer in 22 (17 in PZ and five in TZ) of 128 regions (17.2%). The sensitivity, specificity, and accuracy of each MRI method in the detection of recurrent tumor were 27%, 99%, and 87%, respectively, for T2-weighted imaging; 50%, 98%, and 90%, respectively, for DCE-MRI; and 68%, 95%, and 91%, respectively, for DWI. The sensitivity of DWI in detecting recurrent tumor was significantly higher than that of T2-weighted imaging (p = 0.004). Multiparametric MRI achieved the highest sensitivity (77%) but with slightly decreased specificity (92%).
  
  
  CONCLUSIONS
  These results indicate that a multiparametric MRI protocol that includes DWI provides a sensitive method to detect local recurrence after HDR brachytherapy.
authors.affiliation: Department of Radiology, Kawasaki Medical School, 577 Matsushima, Kurashiki City, Okayama 701-0192, Japan. ttamada@med.kawasaki-m.ac.jp
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Tamada
authors.forename: Teruki
authors.initials: T
authors.lastname: Sone
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Jo
authors.forename: Junichi
authors.initials: J
authors.lastname: Hiratsuka
authors.forename: Atsushi
authors.initials: A
authors.lastname: Higaki
authors.forename: Hiroki
authors.initials: H
authors.lastname: Higashi
authors.forename: Katsuyoshi
authors.initials: K
authors.lastname: Ito
mesh_terms: D000368:Aged; D001706:Biopsy; D001918:Brachytherapy / Q000379:methods*; D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000532:radiotherapy*; D011237:Predictive Value of Tests; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D017430:Prostate-Specific Antigen