Prevention of major biliary complications by fusion imaging for thermal ablation of malignant liver tumors adjacent to the bile ducts: a preliminary comparative study

Intraoperative HIFU ablation of the liver at the hepatocaval confluence as adjunct to surgery: Preliminary animal experiments

Treating colorectal liver metastases (CLMs) located at the hepatocaval confluence with surgery is challenging due to its complexity and associated high risks of perioperative mortality and morbidity. Moreover, thermal ablation techniques are sensitive to the "heat-sink" effect, which reduces their efficacy when tumors are in contact with major blood vessels. In this study we evaluated the feasibility and safety of an intraoperative high-intensity focused ultrasound (HIFU) device for destroying liver tissue volumes sufficiently large to consider treating CLMs at the hepatocaval confluence. Experiments were conducted on six pigs that were followed up to 19 days after the treatment. One HIFU ablation in each animal was created using a 370 s exposure at 100 W. Homogeneous HIFU ablations of liver tissues were safely created at the hepatocaval confluence around the hepatic veins (HVs) in all animals. The targeted HVs were similar to those of humans, with an average diameter of 9.1 ± 1.4 mm. The longest and shortest axes of the HIFU ablations were on average 44.5 ± 11.5 mm and 26.7 ± 4.9 mm, respectively. These values indicate that this device could destroy CLMs up to 2 cm in diameter. Doppler acquisitions, MRI and histological analysis confirmed that HIFU ablations were in contact with the inferior vena cava and extended to the HV wall and that blood flow was maintained. This in vivo preclinical study showed that intraoperative HIFU destruction of liver tissues at the hepatocaval confluence under Doppler ultrasound guidance could therefore represent a new therapeutic option for CLMs.

Three-dimensional ultrasound fusion imaging in precise needle placement for thermal ablation of hepatocellular carcinoma

PURPOSE

To investigate the value of three-dimensional ultrasound fusion imaging (3DUS FI) technique for guiding needle placement in hepatocellular carcinoma (HCC) thermal ablation.

METHODS

A total of 57 patients with 60 HCCs with 3DUS FI-guided thermal ablation were retrospectively included in the study. 3DUS volume data of liver were acquired preoperatively by freehand scanning with the tumor and predetermined 5 mm ablative margin automatically segmented. Plan of needle placement was made through a predetermined simulated ablation zone to ensure a 5 mm ablative margin with the coverage rate toward tumor and ablative margin. With real-time ultrasound and 3DUS fusion imaging, ablation needles were placed according to the plan. After ablation, the ablative margin was immediately evaluated by contrast-enhanced ultrasound and 3DUS fusion imaging. The rate of adequate ablative margin, complete response (CR), local tumor progression (LTP), disease-free survival (DFS), and overall survival (OS) was evaluated.

RESULTS

According to postoperative contrast-enhanced CT or MR imaging, the complete response rate was 100% (60/60), and 83% of tumors (30/36) achieved adequate ablative margin (>5 mm) three-dimensionally. During the follow-up period of 6.0-42.6 months, LTP occurred in 5 lesions, with 1- and 2-year LTP rates being 7.0% and 9.4%. The 1- and 2-year DFS rates were 76.1% and 65.6%, and 1- and 2-year OS rates were 98.1% and 94.0%. No major complications or ablation-related deaths were observed in any patients.

CONCLUSIONS

Three-dimensional ultrasound fusion imaging technique may improve the needle placement of thermal ablation for HCC and reduce the rate of LTP.

Image Fusion Technology in Interventional Radiology

Image fusion technology aims to improve patient outcomes for image-guided interventions by leveraging the strengths of multimodality imaging datasets. This most commonly involves the overlay or co-display of advanced cross-sectional imaging permitting freedom of device placement via conventional image guidance such as ultrasound, fluoroscopy, and computed tomography. This can allow the interventionalist to target and treat lesions that would otherwise be difficult or impossible to visualize and access using conventional imaging guidance. Furthermore, the use of image fusion can allow for procedures traditionally performed with cross-sectional imaging to be performed under ultrasound or fluoroscopy, by importing the data from preacquired cross-sectional imaging into the interventional procedure. This manuscript provides an overview of image fusion technologies used for interventional radiology (IR) guidance, with an emphasis on technical considerations.

Fusion imaging versus ultrasound-guided percutaneous thermal ablation of liver cancer: a meta-analysis

BACKGROUND

Ultrasound-guided percutaneous thermal ablation has become an alternative treatment for small hepatocellular carcinoma (HCC). Recent evidence suggests that fusion imaging (FI) may improve the feasibility and efficacy of thermal ablation for HCC, while the clinical evidence remains limited.

PURPOSE

To compare FI versus ultrasound-guided thermal ablation for HCC.

MATERIAL AND METHODS

Relevant cohort or randomized controlled trials were found by searching Medline, Web of Science, Cochrane Library, and Embase. The pooling of results was performed using a random-effects model incorporating heterogeneity.

RESULTS

In this meta-analysis, 15 studies involving 1472 patients (1831 tumors) for FI-guided ablation and 1380 patients (1864 tumors) for ultrasound-guided ablation were included. Pooled results showed that compared to conventional HCC ablation guided by ultrasound, the FI-guided procedure showed a similar technique efficacy rate (risk ratio [RR] = 1.01, 95% confidence interval [CI] = 1.00-1.02, P = 0.25; I2 = 30%). However, FI-guided tumor ablation was associated with a lower incidence of overall complications (RR = 0.70, 95% CI = 0.50-0.97, P = 0.03; I2 = 0%). Moreover, patients receiving FI-guided tumor ablation had a lower risk of local tumor progression during follow-up than those with ultrasound-guided ablation (RR = 0.61, 95% CI = 0.47-0.78, P < 0.001; I2 = 13%). Subgroup analysis according to FI strategy, imaging techniques in controls, and tumor diameter showed consistent results (p for subgroup difference all >0.05).

CONCLUSION

FI-guided thermal ablation may be more effective and safer than ultrasound-guided ablation for patients with HCC.