Purpose: This systematic review aims to identify, evaluate, and summarize the findings of the literature on existing computational models for radiofrequency and microwave thermal liver ablation planning and compare their accuracy. Methods: A systematic literature search was performed in the MEDLINE and Web of Science databases. Characteristics of the computational model and validation method of the included articles were retrieved. Results: The literature search identified 780 articles, of which 35 were included. A total of 19 articles focused on simulating radiofrequency ablation (RFA) zones, and 16 focused on microwave ablation (MWA) zones. Out of the 16 articles simulating MWA, only 2 used in vivo experiments to validate their simulations. Out of the 19 articles simulating RFA, 10 articles used in vivo validation. Dice similarity coefficients describing the overlap between in vivo experiments and simulated RFA zones varied between 0.418 and 0.728, with mean surface deviations varying between 1.1 mm and 8.67 mm. Conclusion: Computational models to simulate ablation zones of MWA and RFA show considerable heterogeneity in model type and validation methods. It is currently unknown which model is most accurate and best suitable for use in clinical practice.

Background: Early detection of patients at high risk for recurrence or local tumor progression (LTP) following thermal ablation of hepatocellular carcinoma (HCC) is essential for treatment selection and individualized follow-up. This systematic review aims to assess and compare the performance of prognostic models predicting recurrence or LTP in patients with HCC treated with thermal ablation. Methods: PubMed, Web of Science, Cochrane, and Embase were searched for studies developing models to predict recurrence after thermal ablation in treatment-naïve HCC patients, using imaging and clinical data with reported test set performance. Risk of bias and applicability were assessed by the Prediction model Risk of Bias Assessment Tool. Data on model performance, feature extraction and modeling technique was collected. Results: In total, 16 studies comprising 39 prognostic models were included, all developed using retrospective data from China or Korea. Outcomes included recurrence-free survival, (intrahepatic) early recurrence, LTP, late recurrence and aggressive intrasegmental recurrence. Predictive parameters varied across models addressing identical outcomes. Outcome definitions also differed. Nine models were externally validated. Most studies had a high risk of bias due to methodological limitations. Conclusions: Variability in model development methodology and type of predictors was found. Models that integrated multiple types of predictors consistently outperformed those relying on one type. To advance predictive tools toward clinical implementation, future research should prioritize standardized outcome definitions, external testing, and transparent reporting. Until these challenges are addressed, current evaluated models should be regarded as promising but preliminary tools.

To compare the effectiveness of hydrodissection using 0.9 % NaCl (saline) or 5 % dextrose in water during microwave ablation at different hydrodissection fluid thicknesses, in an ex vivo experimental set-up. Two porcine liver parts were placed in a plastic container simulating a superficial liver ablation with adjacent tissue. The space between the livers was filled with either saline or 5 % dextrose in water. Microwave ablation was performed 4 min at 100 W, at 15 mm from the liver surface. Three thermocouples were used to determine the heat propagation: (1) between the microwave ablation antenna and liver surface; (2) 5 mm from the surface of the adjacent tissue; (3) 15 mm from the surface of the adjacent tissue. Forty experiments were performed using hydrodissection fluid thicknesses ranging from 1 to 10 mm. The maximum temperature increase for each thermocouple was determined. A Spearman’s correlation analysis assessed the relationship between the hydrodissection fluid thickness (in millimeters) and the temperature increase (in degrees Celsius) per fluid. At 5 mm within the adjacent tissue, use of 1 mm hydrodissection fluid thickness with 5 % dextrose in water resulted in less temperature increase (4.6 °C) compared to saline (6.8 °C). Additionally, at this distance, a negative correlation was observed between hydrodissection fluid thickness and temperature increase for both saline hydrodissection (r(18) = −0.96, p < 0.001) and 5 % dextrose in water hydrodissection (r(18) = -0.81, p < 0.001), which differs significantly (p = 0.011). Results from this experimental ex vivo study suggest that 5 % dextrose in water may protect adjacent critical structures better from heating during microwave ablation than saline.

Purpose: This study aims to compare local recurrence-free survival (LRFS) in patients with de novo HCC treated with thermal ablation (TA) using real-time CT/MRI-US fusion imaging (FI) or ultrasound (US) for needle placement. Materials and Methods: This single-center retrospective cohort study included patients with de novo HCC who underwent percutaneous TA between January 2013 and December 2021. US was the preferred image guidance modality for ultrasonographically conspicuous lesions; however, for inconspicuous lesions, FI (US-CT or US-MRI) was used for needle placement. Propensity score matching (PSM) with a 1:1 ratio was applied to balance baseline variables between the US- and FI-guided groups. LRFS, disease-free survival (DFS), and overall survival (OS) were compared before and after matching using the log-rank test. Univariate analyses using Cox regression were used to identify prognostic factors for LRFS. Results: A total of 117 patients with 157 lesions were ablated using US and FI needle guidance in 100 and 57 tumors, respectively. PSM yielded 40 tumors in both groups. The 1-year LRFS rates were similar across the groups before and after matching (US: 0.82, FI: 0.94 ( p = 0.07) and US: 0.87, FI: 0.91 ( p = 0.20), respectively). Univariate analysis revealed that only tumor size was a predictive factor for LRFS. Before and after matching, the DFS and OS did not significantly differ between the groups ( p > 0.05). Conclusion: FI-guided needle placement facilitates effective targeting of HCC lesions that are ultrasonographically inconspicuous, yielding LRFS outcomes comparable to those achieved with US guidance for ultrasonographically conspicuous lesions. Level of Evidence 3b , Retrospective Cohort Study. Graphical