title: Role of magnetic resonance diffusion-weighted imaging in evaluating response after chemoembolization of hepatocellular carcinoma.
abstract: OBJECTIVE
  To investigate the value of hepatocellular carcinoma pretreatment apparent diffusion coefficients (ADCs) and its ADCs changes after treatment in predicting and early monitoring the response after chemoembolization.
  
  
  METHODS
  Twenty-five responding and nine nonresponding hepatocellular carcinoma lesions were prospectively evaluated with magnetic resonance diffusion-weighted imaging in 24 h before and in 48 h after chemoembolization. Quantitative ADC maps were calculated with images with b values of 0 and 500 s/mm(2).
  
  
  RESULTS
  Nonresponding lesions had a significantly higher pretreatment mean ADC than did responding lesions (1.726+/-0.323 x 10(-3) mm(2)/s vs.1.294+/-0.18510(-3) mm(2)/s, P< or =0.001). The results of receiver operator characteristic (ROC) analysis for identification of nonresponding lesions showed that threshold ADC value of 1.618 x 10(-3) mm(2)/s had 96.0% sensitivity and 77.8% specificity. After transarterial chemoembolization, responding lesions had a significant increase in %ADC values than did nonresponding lesions (32.63% vs. 5.24%, P=0.025). The results of ROC analysis for identification of responding lesions showed that threshold %ADC value of 16.21% had 72% sensitivity and 100% specificity. No significant change was observed in normal liver parenchyma (P=0.862) and spleen (P=0.052).
  
  
  CONCLUSIONS
  High pretreatment mean ADC value of hepatocellular carcinoma was predictive of poor response to chemoembolization. A significant increase in %ADC value was observed in lesions that responded to chemoembolization.
authors.affiliation: Department of Radiology, Affiliated Changzheng Hospital, The Second Military Medical University, 415 Feng Yang Road, Shanghai 200003, PR China. yuanzheng0404@163.com
authors.forename: Zheng
authors.initials: Z
authors.lastname: Yuan
authors.forename: Xiao-Dan
authors.initials: XD
authors.lastname: Ye
authors.forename: Sheng
authors.initials: S
authors.lastname: Dong
authors.forename: Li-Chao
authors.initials: LC
authors.lastname: Xu
authors.forename: Xue-Yuan
authors.initials: XY
authors.lastname: Xu
authors.forename: Shi-Yuan
authors.initials: SY
authors.lastname: Liu
authors.forename: Xiang-Sheng
authors.initials: XS
authors.lastname: Xiao
mesh_terms: D000328:Adult; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000175:diagnosis* / Q000628:therapy*; D016461:Chemoembolization, Therapeutic / Q000379:methods*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care / Q000379:methods*; D011379:Prognosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome