title: Anterior Prostate Cancer: Diagnostic Performance of T2-Weighted MRI and an Apparent Diffusion Coefficient Map.
abstract: OBJECTIVE
  Diagnosis of anterior prostate cancer is challenging. The purpose of this study was to evaluate the diagnostic performance of T2-weighted imaging and an apparent diffusion coefficient (ADC) map in the detection of anterior prostate cancer and to compare that with the diagnostic performance in the detection of posterior prostate cancer.
  
  
  METHODS
  We retrospectively reviewed the records of 87 patients who underwent 3-T MRI that included T2-weighted imaging and diffusion-weighted imaging before radical prostatectomy. The prostate gland was divided into anterior and posterior segments, and the radiologists interpreted two protocols (T2-weighted imaging alone vs T2-weighted imaging and an ADC map) and sorted the confidence levels for the presence of prostate cancer into five grades. ROC analysis was performed to evaluate the diagnostic performance of each protocol for the detection of anterior and posterior prostate cancers. We also assessed the relative fractions of sensitivity and specificity between anterior and posterior prostate cancers. Additionally, the ADCs of noncancerous anterior fibromuscular stroma were measured and compared with the ADCs of anterior prostate cancers.
  
  
  RESULTS
  The AUCs with T2-weighted imaging alone and with T2-weighted imaging and an ADC map were 0.75 and 0.88 for anterior prostate cancer, respectively, and were 0.70 and 0.81 for posterior prostate cancer. The sensitivity for detecting anterior prostate cancer was 90% and was significantly higher than that for detecting posterior prostate cancer in the protocol using T2-weighted imaging and an ADC map (p = 0.003) when scores of 3-5 were considered as positive for prostate cancer. The ADC was significantly lower in anterior prostate cancer (mean, 0.80 × 10(-3) mm(2)/s) than in noncancerous anterior fibromuscular stroma (1.13 × 10(-3) mm(2)/s) (p < 0.001).
  
  
  CONCLUSIONS
  The protocol using T2-weighted imaging and an ADC map showed higher accuracy for the detection of anterior prostate cancer than for the detection of posterior prostate cancer.
authors.affiliation: 1 Department of Radiology, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Shinmoto
authors.affiliation: 1 Department of Radiology, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan.
authors.forename: Chiharu
authors.initials: C
authors.lastname: Tamura
authors.affiliation: 1 Department of Radiology, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan.
authors.forename: Shigeyoshi
authors.initials: S
authors.lastname: Soga
authors.affiliation: 1 Department of Radiology, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan.
authors.forename: Teppei
authors.initials: T
authors.lastname: Okamura
authors.affiliation: 2 Department of Urology, National Defense Medical College, Tokorozawa, Saitama, Japan.
authors.forename: Akio
authors.initials: A
authors.lastname: Horiguchi
authors.affiliation: 2 Department of Urology, National Defense Medical College, Tokorozawa, Saitama, Japan.
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Asano
authors.affiliation: 1 Department of Radiology, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan.
authors.forename: Tatsumi
authors.initials: T
authors.lastname: Kaji
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000097:blood; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
chemical_list: D014408:Biomarkers, Tumor; D017430:Prostate-Specific Antigen
keywords: DWI; MRI; apparent diffusion coefficient; diagnosis; prostate neoplasms