title: Endorectal MRI for prediction of tumor site, tumor size, and local extension of prostate cancer.
abstract: OBJECTIVE
  To assess the value of endorectal magnetic resonance imaging (MRI) for detecting the tumor site, tumor size, and disease extent in patients with localized prostate cancer.
  
  
  METHODS
  The MRI findings were compared with the histopathologic findings of radical prostatectomy specimens in 95 patients.
  
  
  RESULTS
  The histologic examination revealed 186 cancer foci. Endorectal MRI detected 109 cancer foci. The accuracy, sensitivity, and positive predictive value of endorectal MRI for detecting tumor foci greater than 1.0 cm in diameter was 79.8%, 85.3%, and 92.6%, respectively; the corresponding value for detecting tumor foci smaller than 1.0 cm was 24.2%, 26.2%, and 75.9%, respectively. The maximal tumor diameter on endorectal MRI correlated with that shown by histologic examination for tumors larger than 1.0 cm in diameter. However, it did not correlate significantly with the histologic diameter of tumors smaller than 1.0 cm. The accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of endorectal MRI was 74.7%, 57.1%, 82.1%, 57.1%, and 82.1%, respectively, for the detection of extracapsular extension and was 75.8%, 62.1%, 81.8%, 60.0%, and 83.1%, respectively, for local staging.
  
  
  CONCLUSIONS
  The results of the present study suggest that endorectal MRI is useful for predicting local extension, as well as tumor site and tumor size, of cancer foci greater than 1.0 cm in diameter.
authors.affiliation: Department of Urology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Nakashima
authors.forename: Akihiro
authors.initials: A
authors.lastname: Tanimoto
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Imai
authors.forename: Makio
authors.initials: M
authors.lastname: Mukai
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Horiguchi
authors.forename: Ken
authors.initials: K
authors.lastname: Nakagawa
authors.forename: Mototsugu
authors.initials: M
authors.lastname: Oya
authors.forename: Takashi
authors.initials: T
authors.lastname: Ohigashi
authors.forename: Ken
authors.initials: K
authors.lastname: Marumo
authors.forename: Masaru
authors.initials: M
authors.lastname: Murai
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology* / Q000601:surgery; D000368:Aged; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging / Q000379:methods*; D011237:Predictive Value of Tests; D011300:Preoperative Care; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000473:pathology* / Q000601:surgery; D012007:Rectum; D012669:Seminal Vesicles / Q000473:pathology; D012680:Sensitivity and Specificity