title: Apparent diffusion coefficient quantification as an early imaging biomarker of response and predictor of survival following yttrium-90 radioembolization for unresectable infiltrative hepatocellular carcinoma with portal vein thrombosis.
abstract: OBJECTIVE
  To investigate early diffusion-weighted imaging (DWI) at 30-days post-yttrium-90 (Y-90) radioembolization as a predictor of treatment response and survival in unresectable infiltrative hepatocellular carcinoma (HCC) with portal vein thrombosis (PVT).
  
  
  METHODS
  In a prospective study, 18 consecutive patients with unresectable infiltrative HCC and PVT underwent Y-90 therapy. MR imaging was obtained pre Y-90, and at 1 and 3 months post-therapy with DWI fat-suppressed tri-directional diffusion gradient (b = 50, 400, 800 s/mm(2)). Response was evaluated using target mRECIST and EASL. Relative change in apparent diffusion coefficient (ADC) value of tumors was evaluated. Statistical analysis using receiver operator characteristic curves was performed. Paired t test and Pearson correlation coefficient (r) were used to assess intra- and inter-observer variability. Survival analysis was performed using Kaplan-Meier estimation and log-rank test.
  
  
  RESULTS
  Mean ADC values of all HCC's at baseline and at 30-days post-Y90 therapy was 0.86 × 10(-3) and 1.17×10(-3) mm(2)/s, respectively (p < 0.001). Tumors with objective response by mRECIST had significantly increased ADC value when compared to "non-responders" (1.27 vs. 1.05×10(-3) mm(2)/s, p = 0.002). A >30% increase in ADC value at 30-days was found to be at least 90% sensitive in predicting response at 90 days. A >30% increase in ADC value at 30-days predicted significantly prolonged survival.
  
  
  CONCLUSIONS
  A 30% increase in ADC value at 30-days measured post Y90 is a reproducible early imaging response biomarker predicting tumor response and prolonged survival following Y-90 therapy in infiltrative HCC with PVT.
authors.affiliation: Division of Interventional Radiology & Image Guided Medicine, Department of Radiology, Emory University School of Medicine, Suite AG05, 1364 Clifton Road, NE, Atlanta, GA, 30322, USA, nkokabi@emory.edu.
authors.forename: Nima
authors.initials: N
authors.lastname: Kokabi
authors.forename: Juan C
authors.initials: JC
authors.lastname: Camacho
authors.forename: Minzhi
authors.initials: M
authors.lastname: Xing
authors.forename: Deqiang
authors.initials: D
authors.lastname: Qiu
authors.forename: Hiroumi
authors.initials: H
authors.lastname: Kitajima
authors.forename: Pardeep K
authors.initials: PK
authors.lastname: Mittal
authors.forename: Hyun S
authors.initials: HS
authors.lastname: Kim
mesh_terms: D006528:Carcinoma, Hepatocellular / Q000150:complications / Q000532:radiotherapy*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D004621:Embolization, Therapeutic / Q000379:methods*; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000150:complications / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D011169:Portal Vein; D011237:Predictive Value of Tests; D011446:Prospective Studies; D019275:Radiopharmaceuticals / Q000627:therapeutic use; D016019:Survival Analysis; D016896:Treatment Outcome; D020246:Venous Thrombosis / Q000150:complications / Q000532:radiotherapy*; D015021:Yttrium Radioisotopes / Q000627:therapeutic use*
chemical_list: D019275:Radiopharmaceuticals; D015021:Yttrium Radioisotopes