title: Diagnostic performance of diffusion-weighted magnetic resonance imaging in bladder cancer: potential utility of apparent diffusion coefficient values as a biomarker to predict clinical aggressiveness.
abstract: OBJECTIVE
  The diagnostic performance of diffusion-weighted magnetic resonance imaging (DW-MRI) in bladder cancer and the potential role of apparent diffusion coefficient (ADC) values in predicting pathological bladder cancer phenotypes associated with clinical aggressiveness were investigated.
  
  
  METHODS
  One hundred and four bladder cancer patients underwent DW-MRI and T2-weighted magnetic resonance imaging (T2W-MRI) before transurethral resection. The image sets were reviewed by two independent radiologists. ADC values were measured in 121 eligible tumours.
  
  
  RESULTS
  In detecting patients with bladder cancer, DW-MRI exhibited high sensitivity equivalent to that of T2W-MRI (>90%). Interobserver agreement was excellent for DW-MRI (κ score, 0.88) though moderate for T2W-MRI (0.67). ADC values were significantly lower in high-grade (vs. low-grade, P < 0.0001) and high-stage (T2 vs. T1 vs. Ta, P < 0.0001) tumours. At a cut-off ADC value determined by partition analysis, clinically aggressive phenotypes including muscle-invasive bladder cancer (MIBC) and high-grade T1 disease were differentiated from less aggressive phenotypes with a sensitivity of 88%, a specificity of 85% and an accuracy of 87%.
  
  
  CONCLUSIONS
  DW-MRI exhibits high diagnostic performance in bladder cancer with excellent objectivity. The ADC value could potentially serve as a biomarker to predict clinical aggressiveness in bladder cancer.
authors.affiliation: Department of Urology, Tokyo Medical and Dental University Graduate School, Bunkyo-Ku, Tokyo, 113-8519, Japan.
authors.forename: Shuichiro
authors.initials: S
authors.lastname: Kobayashi
authors.forename: Fumitaka
authors.initials: F
authors.lastname: Koga
authors.forename: Soichiro
authors.initials: S
authors.lastname: Yoshida
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Masuda
authors.forename: Chikako
authors.initials: C
authors.lastname: Ishii
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tanaka
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Komai
authors.forename: Minato
authors.initials: M
authors.lastname: Yokoyama
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Saito
authors.forename: Yasuhisa
authors.initials: Y
authors.lastname: Fujii
authors.forename: Satoru
authors.initials: S
authors.lastname: Kawakami
authors.forename: Kazunori
authors.initials: K
authors.lastname: Kihara
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000378:metabolism*; D004058:Diffusion; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008495:Medical Oncology / Q000379:methods; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging / Q000379:methods; D010641:Phenotype; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D001749:Urinary Bladder Neoplasms / Q000175:diagnosis* / Q000473:pathology*
chemical_list: D015415:Biomarkers