Contrast-enhanced ultrasonography (CEUS)-CT/MRI fusion imaging substantially improved the visibility of small tumors that were inconspicuous on both US and US-CT/MRI fusion imaging, contributing to successful percutaneous radiofrequency ablation.
Percutaneous radiofrequency ablation (RFA) has been widely implemented as a curative treatment for liver malignancies. The overall survival post-RFA is comparable to that of surgical outcomes for small hepatocellular carcinomas (HCCs) (≤ 3 cm). US guidance for RFA is common in Asia because the real-time capability of US allows precise electrode placement. However, precisely targeting small liver malignancies with poor sonographic conspicuity in US-guided RFA is often challenging. To solve this problem, CEUS or real-time fusion imaging (FI) of US and CT/MRI have been used. Both approaches have been reported to improve the confidence for tumor localization in RFA for small HCCs with poor B-mode US visibility. However, when an index tumor is entirely invisible on B-mode US, neither method is ideal, especially for multiple-electrode RFA, due to inherent registration errors on FI or insonation-induced bubble destruction on CEUS with SonoVue. Therefore, there is a clinical need to compensate for the inherent registration errors of US-CT/MRI FI for inconspicuous tumors on both US and US-CT/MRI FI. Recent studies reported that after adding CEUS using Sonazoid (GE Healthcare, Waukesha, WI, USA) or SonoVue to FI, 83.3% to 90% of target liver cancers that were initially difficult to visualize on FI became conspicuous, allowing them to be directly targeted for RFA. However, these studies had limitations, including a retrospective study design, a small sample size (\< 30 inconspicuous tumors), or a short-term follow-up (\< 1 year). Furthermore, no prospective study has explored the value of CEUS-CT/MRI FI, using both SonoVue and Sonazoid as contrast agents, for localizing index tumors and guiding RFA procedures in patients with inconspicuous tumors on B-mode US and reported its therapeutic impact on local tumor control. Therefore, the present study investigated whether CEUS-CT/MRI FI improved the visibility of small (≤ 3 cm) primary and secondary liver tumors that were invisible or difficult to visualize on B-mode US for percutaneous RFA.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
248
In brief, ablation was performed using a 200-W multichannel generator and a switching monopolar technique with separate clustered electrodes. Tumor targeting was done under the guidance of CEUS-CT/MRI FI, and the ablation procedure was monitored with US-FI. The ablation procedure was terminated when the operator expected to complete the ablation of the index tumor with a minimum 5-mm ablative margin on the US-FI images.
Seoul National University Hospital
Seoul, Jongno-gu, South Korea
Local tumor progression rate
Evaluate local tumor progression by follow-up computed tomography (CT) or magnetic resonance imaging (MRI)
Time frame: 12 months after the radiofrequency ablation
Technical success rate of radiofrequency ablation using contrast-enhanced US-CT/MRI fusion image
The technical success of radiofrequency ablation is defined as complete ablation of tumor with safety margin and evaluated by immediate post-procedural computed tomography.
Time frame: Immediately after radiofrequency ablation
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