Superselective Lipiodol CT-guided Microwave Ablation for Small Hepatocellular Carcinoma: A Novel Imaging Guidance Strategy.

[INTRODUCTION] Microwave Ablation (MWA) is a well-established curative therapy for early-stage Hepatocellular Carcinoma (HCC). However, conventional Non- Contrast CT (NCCT) guidance for MWA faces limitations, including poor visualization of isodense lesions and significant needle artifacts, which can compromise targeting accuracy. This study evaluated a novel imaging-guidance strategy utilizing superselective lipiodol CT to explore its feasibility in addressing these challenges.

[MATERIALS AND METHODS] Treatment-naïve patients with BCLC 0/A HCC within the Milan criteria were included in this retrospective study. All patients underwent superselective transarterial lipiodol-only marking followed by CT-guided MWA within 1 week. Treatment efficacy was evaluated based on technical success, Local Tumor Progression (LTP), Intrahepatic Distant Recurrence (IDR), Recurrence-Free Survival (RFS), and Overall Survival (OS). Imaging-guidance performance was descriptively evaluated based on intraprocedural lesion visualization and operator-adjusted window settings used to facilitate needle positioning.

[RESULTS] Forty-five patients with 57 lesions were enrolled. The mean lesion diameter was 18.2 ± 8.8 mm. The initial technical success rate was 95.5% (43/45). The 1-, 2-, and 3-year rates were: LTP: 2.2%, 4.4%, 4.4%; IDR: 24.4%, 37.7%, 44.4%; RFS: 68.9%, 52.7%, 38.2%; OS: 85.1%, 72.4%, and 60.5%. During lipiodol CT-guided procedures, lesions that were isodense and poorly visualized on pre-procedural NCCT were identifiable to the operator, and the window level settings used for final needle positioning confirmation had a mean value of 252.2 ± 75.8 Hounsfield Units.

[DISCUSSION] The superselective lipiodol CT guidance strategy demonstrated feasibility in addressing several practical limitations of conventional NCCT. It allowed visualization of otherwise inconspicuous isodense lesions, supported needle positioning under reduced metallic artifact conditions at empirically adjusted window levels, and aided the visualization of adjacent portal vein branches during the procedure. This approach utilizes Lipiodol primarily as a long-lasting contrast agent for enhanced CT visualization, rather than for its chemotherapeutic or embolic effect.

[CONCLUSION] Superselective lipiodol CT guidance is a feasible imaging approach for intraprocedural lesion visualization and needle positioning during MWA of small HCC in selected procedural scenarios. Controlled comparative or quantitative validation studies are warranted.