# Evaluating Pre-Interventional Administration of a Liver-Specific Contrast Agent During MRI-Guided Thermal Ablation of Malignant Liver Lesions

## TL;DR

This study examines how using a liver-specific contrast agent before MRI-guided ablation affects tumor visibility and treatment assessment.

## Contribution

The study provides empirical evidence on the trade-off between improved lesion visibility and reduced ablation zone contrast when using a hepatocyte-specific contrast agent.

## Key findings

- Contrast agent improved lesion visibility but reduced ablation zone contrast during therapy monitoring.
- Post-procedural imaging showed significantly higher contrast-to-noise ratios in patients without pre-interventional contrast.
- Use of the contrast agent should be limited to cases where lesion delineation is insufficient without it.

## Abstract

Liver cancer and metastatic tumors can be treated with minimally invasive thermoablation procedures like microwave and radiofrequency ablation. Magnetic resonance imaging (MRI) helps guide these procedures by providing clear images of the tumor and surrounding tissue. In some cases, a hepatocyte-specific contrast agent is injected before the procedure to improve tumor visibility. However, this contrast agent may also make it harder to visualize the treated area after ablation, which is crucial for assessing treatment success. This study analyzed data from 57 patients (60 lesions), comparing those who received contrast agent before ablation (Group 1) to those who did not (Group 2). Results showed that contrast administration significantly improved lesion visibility but impaired the differentiation of the ablation zone. The findings will help determine whether using a contrast agent before ablation is beneficial or if it compromises treatment assessment. This research may guide future clinical decisions and improve MRI-based tumor treatment strategies.

Background/Objectives: Hepatocyte-specific contrast agent (Gd-EOB-DTPA) can improve the detection of liver lesions during MRI-guided thermal ablation. This study aimed to assess the impact of contrast agent administration on the delineation of the ablation zone during therapy monitoring. Methods: From 2010 to 2020, 358 patients with primary and secondary hepatic malignancies underwent MRI-guided thermoablation. A total of 27 patients with 30 liver lesions received Gd-EOB-DTPA during the procedure to improve target lesion visibility (Group 1), while 30 patients with 30 lesions underwent MRI-guided thermoablation without contrast administration (Group 2). T1-weighted volumetric interpolated breath-hold examination (VIBE) sequences were used for intraprocedural imaging, and post-procedural control imaging involved intravenous Gadobutrol administration in both groups. The contrast-to-noise ratio (CNR) was assessed for three key structures: the target lesion before applicator placement, the ablation zone during unenhanced therapy monitoring, and the ablation zone in contrast-enhanced control imaging. A statistical comparison of CNR values between the two groups was performed using the non-parametric Wilcoxon test (p < 0.05). Results: The CNR of lesions in group 1 significantly increased following the administration of Gd-EOB-DTPA. During therapy monitoring, the ablation zone in group 2 exhibited a significantly higher CNR compared to group 1 (median: 7.9 vs. 2.1; p < 0.001). Similarly, at the contrast-enhanced final control, the CNR of the ablation zone remained significantly greater in group 2 than in group 1 (median: 7.7 vs. 2.0; p < 0.001). Conclusions: The administration of a hepatocyte-specific contrast agent (Gd-EOB-DTPA) prior to intervention improves the visualization of liver lesions that are poorly demarcated but significantly reduces the contrast of the ablation zone during intra- and post-procedural imaging. Therefore, its use should be reserved for cases in which the target lesion cannot be sufficiently delineated without contrast.