The semi-erect position for better visualization of subphrenic hepatocellular carcinoma during ultrasonography examinations

Usefulness of Body Position Change during Local Ablation Therapies for the High-Risk Location Hepatocellular Carcinoma

Local ablation therapies are important treatment options for early-stage hepatocellular carcinoma (HCC). Various techniques have been used to perform these therapies efficiently and safely. However, few reports have discussed the usefulness of body position change (BPC). This study aimed to investigate the usefulness of BPC during local ablation therapies in patients with HCC. We evaluated 283 HCC nodules that underwent local ablation therapy. These nodules were categorized into high- or low-risk locations on the basis of their proximity to large vessels, adjacent extrahepatic organs, or poor visibility under ultrasound (US) guidance. The technical success rates, procedure time, and prognosis were evaluated. In this study, 176 (62%) nodules were classified in the high-risk location group. The high-risk location group was treated with techniques such as BPC, artificial pleural fluid, artificial ascites, fusion imaging, and contrast-enhanced US more frequently than the low-risk location group. The technical success rates were 96% and 95% for the high- and low-risk location groups, respectively. Within the high-risk location group, those without BPC had a lower success rate than those with BPC (91% vs. 99%, p = 0.015). Notably, BPC emerged as the sole contributing factor to the technical success rate in the high-risk location group (OR = 10, 95% CI 1.2-86, p = 0.034). In contrast, no differences were found in the procedure time, local tumor progression rates, intrahepatic distant recurrence rates, and overall survival between the groups with and without BPC in the high-risk location group. In conclusion, BPC during local ablation therapy in patients with HCC in high-risk locations was safe and efficient. The body position should be adjusted for HCC in high-risk locations to maintain good US visibility and ensure a safe puncture route in patients undergoing local ablation therapies.

Utility of fusion imaging for the evaluation of ultrasound quality in hepatocellular carcinoma surveillance

PURPOSE

This study evaluated the quality of surveillance ultrasound (US) for hepatocellular carcinoma (HCC) utilizing fusion imaging.

METHODS

This research involved a secondary analysis of a prospectively recruited cohort. Under institutional review board approval, participants referred for surveillance US who had undergone liver computed tomography (CT) or magnetic resonance imaging (MRI) within the past year were screened between August 2022 and January 2023. After patient consent was obtained, the US visualization score in the Liver Imaging Reporting and Data System was assessed with fusion imaging at the time of examination. This score was compared to that of conventional US using the extended McNemar test. Multivariable logistic regression analysis was used to identify factors independently associated with a US visualization score of B or C. Factors limiting visualization of focal lesions were recorded during fusion imaging.

RESULTS

Among the 105 participants (mean age, 59±11 years; 66 men), US visualization scores of B and C were assigned to 57 (54.3%) and 17 (16.2%) participants, respectively, by conventional US and 54 (51.4%) and 32 (30.5%) participants, respectively, by fusion imaging. The score distribution differed significantly between methods (P=0.010). Male sex was independently associated with US visualization scores of B or C (adjusted odds ratio, 3.73 [95% confidence interval, 1.30 to 10.76]; P=0.015). The most common reason (64.5%) for lesion nondetection was a limited sonic window.

CONCLUSION

Conventional US may underestimate the limitations of the sonic window relative to real-time fusion imaging with pre-acquired CT or MRI in the surveillance of HCC.

Tips for Preparing and Practicing Thermal Ablation Therapy of Hepatocellular Carcinoma

Thermal ablation therapy, including radiofrequency ablation (RFA) and microwave ablation (MWA), is considered the optimal locoregional treatment for unresectable early-stage hepatocellular carcinomas (HCCs). Percutaneous image-guided ablation is a minimally invasive treatment that is being increasingly performed because it achieves good clinical outcomes with a lower risk of complications. However, the physics and principles of RFA and MWA markedly differ. Although percutaneous thermal ablation under image guidance may be challenging in HCC cases with limited access or a risk of thermal injury, a number of ablative techniques, each of which may be advantageous and disadvantageous for individual cases, are available. Furthermore, even when a HCC is eligible for ablation based on tumor selection and technical factors, additional patient factors may have an impact on whether it is the appropriate treatment choice. Therefore, a basic understanding of the advantages and limitations of each ablation device and imaging guidance technique, respectively, is important. We herein provide an overview of the basic principles of tissue heating in thermal ablation, clinical and laboratory parameters for ablation therapy, preprocedural management, imaging assessments of responses, and early adverse events. We also discuss associated challenges and how they may be overcome using optimized imaging techniques.

Percutaneous radiofrequency ablation for hepatic metastasis of colorectal cancer: assessment of tumor visibility and the feasibility of the procedure with planning ultrasonography

Purpose

The aim of this study was to assess the incidence and causes of percutaneous radiofrequency ablation (RFA) infeasibility in cases of metastatic colorectal cancer and to evaluate factors affecting the invisibility of the tumor on planning ultrasonography (US).

Methods

This study screened 386 patients who underwent planning US using fusion imaging and/or contrast-enhanced US for percutaneous RFA for suspected metastatic colorectal cancer between January 2013 and December 2020, from whom 136 patients with a single hepatic metastasis from colorectal cancer measuring <3 cm were included. The factors related to the infeasibility of percutaneous RFA were investigated. Univariate and multivariate analyses were performed to assess the factors associated with tumor invisibility on planning US.

Results

Among the 136 patients, percutaneous RFA was considered infeasible in 24.3% (33/136) due to a high risk of the heat-sink effect caused by the abutment of a large vessel (n=12), an inconspicuous tumor on planning US (n=11), a high risk of collateral thermal damage to an adjacent organ (n=8), and the absence of a safe electrode path (n=2). In univariate and multivariate analyses, tumor size was a statistically significant factor affecting invisibility on planning US (P=0.003 and P=0.018, respectively).

Conclusion

Percutaneous RFA was infeasible in approximately one-fourth of patients with metastatic colorectal cancer. The reason for the infeasibility was mainly an unfavorable tumor location and invisibility on planning US. Small tumor size was the sole significant factor affecting the invisibility of hepatic metastases on planning US.