title: Elastographic Strain Index in the Evaluation of Focal Lesions Detected With Transrectal Sonography of the Prostate Gland.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the value of elastography in evaluating focal lesions detected by transrectal sonography and to suggest a reference strain index.
  
  
  METHODS
  Sixty-nine patients with focal lesions on transrectal sonography were referred to our department for prostate biopsy. Focal lesions were classified as either highly or less suspicious lesions by our criteria. A strain index from elastography was calculated for the focal lesions. Systematic 12-core randomized biopsies plus 2 targeted biopsies were performed. The mean strain indices for malignant and benign focal lesions were compared, and a cutoff strain index was attained to maximize the sensitivity and specificity for prostate cancer. Strain indices were correlated with Gleason scores.
  
  
  RESULTS
  The mean strain index ± SD for malignant focal lesions (3.26 ± 1.77) was significantly higher than that for benign focal lesions (2.16 ± 1.52; P = .008). The sensitivity, specificity, and area under the receiver operating characteristic curve for diagnosing cancer were 66.7%, 71.1%, and 0.701, respectively, at a strain index cutoff value of greater than 2.4. The strain index showed a moderate linear correlation with the Gleason score (r = 0.441; P = .013).
  
  
  CONCLUSIONS
  Any focal lesion on transrectal sonography with a strain index of greater than 2.4 is at risk for prostate cancer.
authors.affiliation: Department of Radiology, Seoul National University Bundang Hospital, Bundang-gu, Korea.
authors.forename: Sung Il
authors.initials: SI
authors.lastname: Hwang
authors.affiliation: Department of Radiology, Seoul National University Bundang Hospital, Bundang-gu, Korea. hakjlee@snu.ac.kr.
authors.forename: Hak Jong
authors.initials: HJ
authors.lastname: Lee
authors.affiliation: Department of Urology, Seoul National University Bundang Hospital, Bundang-gu, Korea.
authors.forename: Sang Eun
authors.initials: SE
authors.lastname: Lee
authors.affiliation: Department of Urology, Seoul National University Bundang Hospital, Bundang-gu, Korea.
authors.forename: Sung Kyu
authors.initials: SK
authors.lastname: Hong
authors.affiliation: Department of Urology, Seoul National University Bundang Hospital, Bundang-gu, Korea.
authors.forename: Seok-Soo
authors.initials: SS
authors.lastname: Byun
authors.affiliation: Department of Pathology, Seoul National University Bundang Hospital, Bundang-gu, Korea.
authors.forename: Gheeyoung
authors.initials: G
authors.lastname: Choe
mesh_terms: D000368:Aged; D054459:Elasticity Imaging Techniques / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011467:Prostate / Q000000981:diagnostic imaging; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
keywords: cancer; elastography; genitourinary ultrasound; prostate; sonography