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SIR 2025

Interventional Oncology

Traditional Poster

Session: Traditional Poster Presentations

69 - Transarterial Lipiodol Staining Impact on Microwave Ablation Zone Dimensions and Outcomes in Treatment of Hepatocellular Carcinoma

Monday, March 31, 2025
12:10 PM – 1:10 PM CT
Location: Music City Center, Expo Poster Area
Purpose: Transarterial lipiodol staining (TLS) of hepatocellular carcinoma (HCC) is useful to improve targeting of lesions poorly visualized by non-contrast CT and ultrasound. In our institution, TLS with same day CT microwave ablation (MWA) is frequently performed without bland embolization or cTACE. This study aims to analyze if TLS-MWA has a measurable embolic effect on MWA dimensions and improves 1-year local disease recurrence. 

Materials and Methods: Liver MWA cases performed between 6/2019–6/2023 at a single tertiary referral center were screened. Inclusion criteria were HCC, high power MWA setting (Solero 140W, 6 minutes; Neuwave 65W, 10 minutes), same day post-MWA multiphasic CT, and 1 year follow-up with multiphasic imaging. A total of 317 MWA cases were screened with 24 TLS-MWAs meeting inclusion criteria (10 Solero, 14 Neuwave). Control standard MWA lesions for comparison were selected 1:1 (n = 24) using same device and MWA settings without lipiodol staining and tumor visualization by noncontrast CT or ultrasound. 20 patients were included in the lipiodol group (17M, 3F, mean 62.9 years) and 23 patients in the control group (17M, 6F, mean 62.7 years). Lesion size, maximal MWA short axis diameter (SAD), long axis diameter (LAD), and minimal ablation margin was measured using multiplanar reformatting. Additional variables collected included subcapsular or perivascular location, lipiodol lesion dimensions before and after MWA to assess for tissue contracture, minimal ablation margin, and 1-year local disease recurrence.

Results: Pre-treatment tumor volume was 4.0 ± 2.9 mL for TLS-MWA cases and 4.7 ± 3.0 mL for standard MWA cases (p = 0.39). No difference was observed comparing TLS-MWA dimensions to standard MWA (24 TLS-MWAs vs 24 standard MWAs, two-tailed t-test): SAD, 3.2 ± 0.3 cm vs 3.3 + 0.4 cm (p = 0.28); LAD, 4.1 ± 0.8 cm vs 4.4 ± 0.7 cm (p = 0.14). Analysis of tumor contracture demonstrated a significant decrease in tumor dimensions (pre-MWA lipiodol lesion versus post-MWA):  SAD, 1.8 ± 0.5 cm vs 1.4 ± 0.4 cm (p < 0.001), 18% contracture; volume, 3.8 ± 3.0 mL vs 2.0 ± 1.5 mL (p < 0.01), 46% contracture. Tumor margins were visible immediately post-MWA for all TLS-MWA cases, but not in standard MWA cases. Mean minimal ablation margin for TLS-MWA was 6.0 ± 1.9 mm. Excluding retreatment, 1-year local disease recurrence was 15% for TLS-MWA cases and 26% for standard MWA cases (p = 0.62).
 


Conclusion: In this limited retrospective review, TLS-MWA demonstrates successful MWA of poorly visualized HCC tumors. TLS-MWA did not demonstrate increased MWA dimensions as reported in TACE-MWA investigations.