Correlation between computed electric dose maps and early post-operative MRI for the evaluation of irreversible electroporation

<i>Objective.</i>To correlate numerical simulations of the electric dose distribution with early post-operative MRI following irreversible electroporation (IRE) treatment of hepatocellular carcinoma (HCC).<i>Approach.</i>A standard linear electrostatic model was employed to simulate the three-dimensional electric field (EF) distribution using real electric pulses and geometrical characteristics and intraoperative cone-beam CT (CBCT) data. Spatial registration between intraoperative CBCT and post-operative MRI was performed using both rigid and deformable methods, ranging from simple global translations based on anatomical landmarks to advanced deformable image registration (DIR) techniques accounting for elastic tissue deformations.<i>Main results.</i>The proposed approach was retrospectively evaluated using data from 22 patients who underwent IRE liver ablation (one patient underwent two distinct IRE procedures), resulting in a total of 23 procedures. The most accurate correspondence between predicted and observed ablation zones was achieved using a dose threshold of approximately 350 V cm^-1, yielding a median dice similarity coefficient around 0.74, indicative of substantial spatial overlap. Although elastic DIR approaches applied to segmented liver regions provided the highest registration accuracy, the simpler translational registration based on manually selected landmarks demonstrated surprisingly robust performance in localizing the simulated EF within the actual ablation zone.<i>Significance.</i>These findings contribute to the standardization of IRE efficacy assessment on MRI and highlight the significant potential EF simulations to predict the extent of tissue ablation in IRE procedures for HCC. This approach may offer a valuable tool for improving intraoperative decision-making and post-operative assessment.