title: MR imaging to assess immediate response to irreversible electroporation for targeted ablation of liver tissues: preclinical feasibility studies in a rodent model.
abstract: OBJECTIVE
  To test the hypothesis that magnetic resonance (MR) imaging measurements can be used to immediately detect treated tissue regions after irreversible electroporation (IRE) ablation procedures in rodent liver tissues.
  
  
  METHODS
  All experiments received institutional animal care and use committee approval. In four rats for preliminary studies and 18 rats for formal assessment, MR imaging-compatible electrodes were inserted into the liver and MR imaging-monitored IRE procedures were performed at one of three electrode voltages (1000, 1500, or 2500 V), with T1- and T2-weighted images acquired before and immediately after application of the IRE pulses. MR imaging measurements were compared with both finite element modeling (FEM)-anticipated ablation zones and histologically confirmed ablation zones at necropsy. Intraclass and Spearman correlation coefficients were calculated for statistical comparisons.
  
  
  RESULTS
  MR imaging measurements permitted immediate depiction of IRE ablation zones that were hypointense on T1-weighted images and hyperintense on T2-weighted images. MR imaging-based measurements demonstrated excellent consistency with FEM-anticipated ablation zones (r > 0.90 and P < .001 for both T1- and T2-weighted images). MR imaging measurements were also highly correlated with histologically confirmed ablation zone measurements (rho > 0.90 and P < .001 for both T1- and T2-weighted images).
  
  
  CONCLUSIONS
  MR imaging permits immediate depiction of ablated tissue zones for monitoring of IRE ablation procedures. These measurements could potentially be used during treatment to elicit repeat application of IRE pulses or adjustments to electrode positions to ensure complete treatment of targeted lesions.
authors.affiliation: Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA.
authors.forename: Yue
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yang
authors.initials: Y
authors.lastname: Guo
authors.forename: Ann B
authors.initials: AB
authors.lastname: Ragin
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Lewandowski
authors.forename: Guang-Yu
authors.initials: GY
authors.lastname: Yang
authors.forename: Grace M
authors.initials: GM
authors.lastname: Nijm
authors.forename: Alan V
authors.initials: AV
authors.lastname: Sahakian
authors.forename: Reed A
authors.initials: RA
authors.lastname: Omary
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Larson
mesh_terms: D000818:Animals; D017115:Catheter Ablation / Q000379:methods*; D018274:Electroporation / Q000379:methods*; D005240:Feasibility Studies; D006498:Hepatectomy / Q000379:methods*; D006801:Humans; D008099:Liver / Q000033:anatomy & histology* / Q000601:surgery*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D023421:Models, Animal; D051381:Rats; D017207:Rats, Sprague-Dawley; D025321:Surgery, Computer-Assisted / Q000379:methods*