title: MRI techniques for prediction of local tumor progression after high-intensity focused ultrasonic ablation of prostate cancer.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the diagnostic performance of dynamic contrast-enhanced MRI (DCE-MRI) and of T2-weighted MRI with diffusion-weighted imaging (DWI) for predicting local tumor progression after high-intensity focused ultrasonic ablation of localized prostate cancer.
  
  
  METHODS
  Twenty-seven patients who had increased levels of prostate-specific antigen after high-intensity focused ultrasonic ablation underwent MRI and endorectal biopsy. The MR images and biopsy results were correlated for six prostate sectors. Residual or recurrent prostate cancer after treatment was defined as local tumor progression if the biopsy results showed cancer foci. Two readers blinded to the clinical findings and biopsy results used a 5-point scale to independently assess DCE-MR images and T2-weighted and diffusion-weighted MR images. The results were compared by use of the McNemar test with Bonferroni correction, generalized estimating equations, and receiver operating characteristic analysis.
  
  
  RESULTS
  After high-intensity focused ultrasonic ablation, local tumor progression was pathologically detected in 54 (33%) of 162 sectors in 18 patients. The sensitivities of DCE-MRI and T2-weighted MRI with DWI were 80% and 63% for reader 1 (p = 0.004) and 87% and 70% for reader 2 (p = 0.004). The specificities of DCE-MRI and T2-weighted MRI with DWI were 68% and 78% for reader 1 (p = 0.002) and 63% and 74% for reader 2 (p < 0.001). The accuracy rates of DCE-MRI and T2-weighted MRI with DWI were 72% and 73% for reader 1 (p > 0.05) and 71% and 73% for reader 2 (p > 0.05). The areas under the receiver operating characteristic curve for DCE-MRI and T2-weighted MRI with DWI were 0.77 and 0.77 for reader 1 and 0.85 and 0.81 for reader 2.
  
  
  CONCLUSIONS
  For prediction of local tumor progression of prostate cancer after high-intensity focused ultrasonic ablation, DCE-MRI was more sensitive than T2-weighted MRI with DWI, but T2-weighted MRI with DWI was more specific than DCE-MRI.
authors.affiliation: Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-dong, Kangnam-gu, Seoul, Republic of Korea 135-710. chankyokim@skku.edu <chankyokim@skku.edu>
authors.forename: Chan Kyo
authors.initials: CK
authors.lastname: Kim
authors.forename: Byung Kwan
authors.initials: BK
authors.lastname: Park
authors.forename: Hyun Moo
authors.initials: HM
authors.lastname: Lee
authors.forename: Sam Soo
authors.initials: SS
authors.lastname: Kim
authors.forename: EunJu
authors.initials: E
authors.lastname: Kim
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D003287:Contrast Media; D019786:Gadolinium DTPA; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011471:Prostatic Neoplasms / Q000473:pathology* / Q000628:therapy*; D012372:ROC Curve; D012189:Retrospective Studies; D036761:Ultrasound, High-Intensity Focused, Transrectal
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA