title: Diffusion-weighted magnetic resonance imaging to predict response of hepatocellular carcinoma to chemoembolization.
abstract: OBJECTIVE
  To investigate whether intra-procedural diffusion-weighted magnetic resonance imaging can predict response of hepatocellular carcinoma (HCC) during transcatheter arterial chemoembolization (TACE).
  
  
  METHODS
  Sixteen patients (15 male), aged 59 +/- 11 years (range: 42-81 years) underwent a total of 21 separate treatments for unresectable HCC in a hybrid magnetic resonance/interventional radiology suite. Anatomical imaging and diffusion-weighted imaging (b = 0, 500 s/mm(2)) were performed on a 1.5-T unit. Tumor enhancement and apparent diffusion coefficient (ADC, mm(2)/s) values were assessed immediately before and at 1 and 3 mo after TACE. We calculated the percent change (PC) in ADC values at all time points. We compared follow-up ADC values to baseline values using a paired t test (alpha = 0.05).
  
  
  RESULTS
  The intra-procedural sensitivity, specificity, and positive and negative predictive values (%) for detecting a complete or partial 1-mo tumor response using ADC PC thresholds of +/-5%, +/-10%, and +/-15% were 77, 67, 91, and 40; 54, 67, 88, and 25; and 46, 100, 100, and 30, respectively. There was no clear predictive value for the 3-mo follow-up. Compared to baseline, the immediate post-procedure and 1-mo mean ADC values both increased; the latter obtaining statistical significance (1.48 +/- 0.29 mm(2)/s vs 1.65 +/- 0.35 x 10(-3) mm(2)/s, P < 0.014).
  
  
  CONCLUSIONS
  Intra-procedural ADC changes of > 15% predicted 1-mo anatomical HCC response with the greatest accuracy, and can provide valuable feedback at the time of TACE.
authors.affiliation: Department of Radiology, Northwestern University Feinberg School of Medicine, 737 N. Michigan Ave., Chicago, IL 60611, United States.
authors.forename: Johnathan C
authors.initials: JC
authors.lastname: Chung
authors.forename: Neel K
authors.initials: NK
authors.lastname: Naik
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Lewandowski
authors.forename: Jie
authors.initials: J
authors.lastname: Deng
authors.forename: Mary F
authors.initials: MF
authors.lastname: Mulcahy
authors.forename: Laura M
authors.initials: LM
authors.lastname: Kulik
authors.forename: Kent T
authors.initials: KT
authors.lastname: Sato
authors.forename: Robert K
authors.initials: RK
authors.lastname: Ryu
authors.forename: Riad
authors.initials: R
authors.lastname: Salem
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Larson
authors.forename: Reed A
authors.initials: RA
authors.lastname: Omary
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000473:pathology / Q000628:therapy*; D016461:Chemoembolization, Therapeutic / Q000379:methods*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D006801:Humans; D008113:Liver Neoplasms / Q000473:pathology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D016896:Treatment Outcome