Detection of Ablation Boundaries Using Different MR Sequences in a Swine Liver Model

Area of Science:

• Radiology and Imaging
• Interventional Radiology
• Medical Physics

Background:

• Radiofrequency ablation (RFA) is a minimally invasive technique used to treat various tumors.
• Accurate assessment of the ablation zone is crucial for treatment efficacy and patient outcomes.
• Magnetic resonance (MR) imaging is a valuable tool for monitoring RFA, but optimal sequences require definition.

Purpose of the Study:

• To identify the most effective MR imaging sequences for evaluating ablation zones following RFA.
• To compare the accuracy of different MR sequences against histological findings.

Main Methods:

• Percutaneous MR-guided RFA was performed on swine liver models.
• Multiple pre- and post-contrast MR sequences were acquired.
• Ablation zones were segmented and compared to histological analysis using Dice Similarity Coefficient (DSC) and Contrast-to-Noise Ratio (CNR).

Main Results:

• The post-contrast T1 3D Turboflash (TFL) sequence demonstrated high accuracy in depicting ablation zones.
• T1 VIBE post-contrast, T2 SPACE, and other post-contrast sequences showed no significant size difference compared to histology.
• Pre-contrast T1 VIBE sequences underestimated ablation zone size, while T2 turbo spin-echo overestimated it.

Conclusions:

• Post-contrast T1 3DTFL is the optimal sequence for assessing RFA ablation zones.
• T1 VIBE post-contrast provides a practical balance between imaging time and accuracy for RFA zone evaluation.