title: Apparent diffusion coefficient value reflects invasive and proliferative potential of bladder cancer.
abstract: OBJECTIVE
  To elucidate a role of apparent diffusion coefficient (ADC) value as a biomarker of bladder cancer, we investigated its associations with Ki-67 labeling index (LI) along with classical clinicopathological prognosticators.
  
  
  METHODS
  Diffusion-weighted MRI (DW-MRI) at 1.5 Tesla using b-values of 0, 500, 1000, and 2000 s/mm(2) was prospectively taken before transurethral resection by 132 bladder cancer patients. ADC value of index tumors was measured and compared with clinicopathological prognosticators including Ki-67 LI.
  
  
  RESULTS
  ADC value was significantly lower in tumors with higher Ki-67 LIs, sessile tumors (versus papillary), larger tumors, higher grade disease, and higher T stage disease. ADC value inversely correlated with Ki-67 LI (ρ = -0.57; P < 0.0001). On multiple regression analysis, T stage and Ki-67 LI significantly correlated with ADC value. The Akaike information criterion confirms these two parameters constitute the best model for determining ADC value. Similarly, T stage and ADC value significantly correlated with Ki-67 LI and these two parameters composed the best model for predicting Ki-67 LI.
  
  
  CONCLUSIONS
  ADC value would reflect T stage and Ki-67 LI, representing invasive and proliferative potential, respectively. ADC value is likely to serve as a biomarker reflecting aggressiveness of bladder cancer.
authors.affiliation: Department of Urology, Tokyo Medical and Dental University Graduate School, Tokyo, Japan.
authors.forename: Shuichiro
authors.initials: S
authors.lastname: Kobayashi
authors.forename: Fumitaka
authors.initials: F
authors.lastname: Koga
authors.forename: Kohei
authors.initials: K
authors.lastname: Kajino
authors.forename: Soichiro
authors.initials: S
authors.lastname: Yoshita
authors.forename: Chikako
authors.initials: C
authors.lastname: Ishii
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tanaka
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Saito
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Masuda
authors.forename: Yasuhisa
authors.initials: Y
authors.lastname: Fujii
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Yamada
authors.forename: Kazunori
authors.initials: K
authors.lastname: Kihara
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000378:metabolism; D049109:Cell Proliferation; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D019394:Ki-67 Antigen / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009361:Neoplasm Invasiveness; D011379:Prognosis; D011446:Prospective Studies; D001749:Urinary Bladder Neoplasms / Q000175:diagnosis / Q000473:pathology*
chemical_list: D015415:Biomarkers; D019394:Ki-67 Antigen
keywords: Ki-67 antigen; apparent diffusion coefficient; bladder cancer; diffusion-weighted magnetic resonance imaging