title: Value of diffusion-weighted imaging at 3 T for prediction of extracapsular extension in patients with prostate cancer: a preliminary study.
abstract: OBJECTIVE
  The purpose of this study was to retrospectively investigate the value of adding diffusion-weighted imaging (DWI) to T2-weighted imaging for the prediction of extracapsular extension (ECE) in patients with prostate cancer, as well as to compare apparent diffusion coefficients (ADCs) between patients with and without ECE.
  
  
  METHODS
  Seventy-six patients with suspected prostate cancer underwent T2-weighted imaging and DWI at 3 T using a phased-array coil, followed by radical prostatectomy. For prediction of ECE, the prostate was divided into six sectors. Two experienced radiologists analyzed T2-weighted images alone and in combination with DWI in consensus and rated the likelihood of ECE on a five-point scale. Tumor ADC values were measured, and the results were compared between patients with and without ECE.
  
  
  RESULTS
  Of the 456 sectors studied, 74 (16%) were positive for ECE in 31 patients. For prediction of ECE, the specificity and accuracy of combined T2-weighted imaging and DWI were 94.5% and 91.7%, respectively, superior to those of T2-weighted imaging alone (87.2% and 81.2%, respectively) (p < 0.001). On receiver operating characteristic analysis, the area under the curve (Az) of combined T2-weighted imaging and DWI (Az = 0.900) was significantly greater than that of T2-weighted imaging alone (Az = 0.828) (p < 0.001). The mean tumor ADC values were significantly lower in patients with ECE than patients without ECE (p < 0.001).
  
  
  CONCLUSIONS
  DWI at 3 T in addition to T2-weighted imaging improves the ability to predict ECE in patients with prostate cancer. Furthermore, tumor ADC values in patients with and without ECE are significantly different.
authors.affiliation: 1 Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-dong, Gangnam-gu, Seoul, Republic of Korea.
authors.forename: Yousun
authors.initials: Y
authors.lastname: Chong
authors.forename: Chan Kyo
authors.initials: CK
authors.lastname: Kim
authors.forename: Sung Yoon
authors.initials: SY
authors.lastname: Park
authors.forename: Byung Kwan
authors.initials: BK
authors.lastname: Park
authors.forename: Ghee Young
authors.initials: GY
authors.lastname: Kwon
authors.forename: Jung Jae
authors.initials: JJ
authors.lastname: Park
mesh_terms: D000368:Aged; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000473:pathology* / Q000601:surgery; D012189:Retrospective Studies; D012680:Sensitivity and Specificity