Ablation Of Liver Tumors Research Articles

Thermoacoustic CBE imaging for monitoring microwave ablation of the liver: A feasibility study

Microwave ablation is the most commonly used minimally invasive technique for thermal ablation of liver tumors, and accurate monitoring of the ablation area is crucial for evaluating treatment efficacy. While traditional imaging techniques play an important role in clinical monitoring, they still face several insurmountable challenges. Microwave-induced thermoacoustic imaging (TAI) has emerged as a promising modality for ablation detection due to its high resolution and deep imaging capabilities. To further enhance the effectiveness of TAI in ablation monitoring, we propose a technique based on thermoacoustic changes in backscattered energy (CBE) imaging. This method accurately delineates the liver ablation area by monitoring temperature variations before and after ablation. Experimental results show that thermoacoustic CBE imaging offers significant advantages over traditional TAI, achieving accuracies of 97.12% in ex vivo and 93.46% in in vivo experiments. Its superior resolution makes it an ideal choice for monitoring tissue damage during microwave ablation.

Percutaneous Delivery of Oncogel for Targeted Liver Tumor Ablation and Controlled Release of Therapeutics.

Advanced-stage liver cancers are associated with poor prognosis and have limited treatment options, often leading the patient to hospice care. Percutaneous intratumoral injection of anticancer agents has emerged as a potential alternative to systemic therapy to overcome tumor barriers, increase bioavailability, potentiate immunotherapy, and avoid systemic toxicity, which advanced-stage cancer patients cannot tolerate. Here, an injectable OncoGel (OG) comprising of a nanocomposite hydrogel loaded with an ionic liquid (IL) is developed for achieving a predictable and uniform tumor ablation and long-term slow release of anticancer agents into the ablation zone. Rigorous mechanical, physiochemical, drug release, cytotoxicity experiments, and ex vivo human tissue testing identify an injectable version of the OG with bactericidal properties against highly resistant bacteria. Intratumoral injection of OG loaded with Nivolumab (Nivo) and doxorubicin (Dox) into highly malignant tumor models in mice, rats, and rabbits demonstrates enhanced survival and tumor regression associated with robust tissue ablation and drug distribution throughout the tumor. Mass cytometry and proteomic studies in a mouse model of colorectal cancer that often metastasizes to the liver indicate an enhanced anticancer immune response following the intratumoral injection of OG. OG may augment immunotherapy and potentially improve outcomes in liver cancer patients.

Percutaneous Delivery of Oncogel for Targeted Liver Tumor Ablation and Controlled Release of Therapeutics (Adv. Mater. 45/2024)

Percutaneous Delivery of Oncogel for Targeted Liver Tumor Ablation and Controlled Release of Therapeutics (Adv. Mater. 45/2024)

Multi-stage automatic and rapid ablation and needle trajectory planning method for CT-guided percutaneous liver tumor ablation.

Computer-assisted planning methods have increasingly contributed to preoperative ablation planning; however, these methods cannot automatically obtain the final optimal solution within a short time and are rarely validated in practice, greatly limiting their clinical applicability. We aimed to propose a full-automatic multi-stage ablation and needle trajectory planning method for CT-guided percutaneous liver ablation to attain the final optimal plans under multiple clinical constraints rapidly. Our proposed method integrates the ablation zone planning fulfilling complete tumor coverage and critical structure avoidance while reaching a trade-off between ablation number and healthy tissue damage, and needle trajectory planning under multiple clinical constraints. Our needle trajectory planning determines feasible skin entry regions based on hard constraints, where the multi-objective optimization (MOO) considering soft constraints is performed using the Pareto Optimality and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) methods for the final optimal solution. The performance of our proposed method was evaluated on 30 tumors of various characteristics from 23 patients and clinically validated in five clinical cases. Our proposed method achieved 99.8% treatment zone coverage and 40.5% ablation efficiency without involving critical structures, and completely satisfied multiple clinical constraints in all needle trajectory planning results. The average planning time was 23.6 s for tumors of different sizes. All the plans were considered clinically acceptable by the doctors' evaluation. Our method achieved complete tumor coverage without complications in clinical case validation. Our proposed planning method can generate a final optimal plan satisfying multiple clinical constraints within a short time, potentially facilitating preoperative planning for hepatic tumor ablation.

Endoscopic ultrasound-guided vascular interventions: A review (with videos).

Endoscopic ultrasound (EUS) has evolved from a diagnostic to an interventional modality, allowing precise vascular access and therapy. EUS-guided vascular access of the portal vein has received increasing attention in recent years as a diagnostic and therapeutic tool. EUS-guided portal pressure gradient directly measures the hepatic vein portal pressure gradient and is crucial for understanding of liver function and prognostication of liver disease. EUS facilitates the sampling of portal venous blood to obtain circulating tumor cells (CTCs) in pancreatobiliary malignancies. This technique aids in the diagnosis and staging of cancers. EUS-guided interventions have a substantial potential for diagnosing portal vein tumor thrombus (PVTT) in patients with hepatocellular carcinoma. EUS-guided coil and glue embolization have higher efficacy for the treatment of gastric varices than direct endoscopic glue. Pseudoaneurysm (PsA), a rare vascular complication of acute and chronic pancreatitis, is typically managed with interventional radiology (IR)-guided embolization and surgery. EUS is increasingly used in specialized centers for non-variceal gastrointestinal bleeding, particularly for pseudoaneurysm-related bleeding. There is limited data on EUS-guided intervention for bleeding ectopic varices, rectal varices and Dieulafoy lesions, but it is becoming more widely accepted. In this extensive review, we evaluated both current and potential future applications of EUS-guided vascular interventions, including EUS-guided gastric variceal bleed therapy, rectal and ectopic varices, pseudoaneurysmal bleeding, splenic artery embolization, portal pressure gradient measurement, portal vein sampling for CTCs, fine needle aspiration of PVTT, intrahepatic portosystemic shunt placement, liver tumor ablation and EUS-guided cardiac intervention.

The #HOPE4LIVER Single-Arm Pivotal Trial for Histotripsy of Primary and Metastatic Liver Tumors.

Background Histotripsy is a nonthermal, nonionizing, noninvasive, focused US technique that relies on cavitation for mechanical tissue breakdown at the focal point. Preclinical data have shown its safety and technical success in the ablation of liver tumors. Purpose To evaluate the safety and technical success of histotripsy in destroying primary or metastatic liver tumors. Materials and Methods The parallel United States and European Union and England #HOPE4LIVER trials were prospective, multicenter, single-arm studies. Eligible patients were recruited at 14 sites in Europe and the United States from January 2021 to July 2022. Up to three tumors smaller than 3 cm in size could be treated. CT or MRI and clinic visits were performed at 1 week or less preprocedure, at index-procedure, 36 hours or less postprocedure, and 30 days postprocedure. There were co-primary end points of technical success of tumor treatment and absence of procedure-related major complications within 30 days, with performance goals of greater than 70% and less than 25%, respectively. A two-sided 95% Wilson score CI was derived for each end point. Results Forty-four participants (21 from the United States, 23 from the European Union or England; 22 female participants, 22 male participants; mean age, 64 years ± 12 [SD]) with 49 tumors were enrolled and treated. Eighteen participants (41%) had hepatocellular carcinoma and 26 (59%) had non-hepatocellular carcinoma liver metastases. The maximum pretreatment tumor diameter was 1.5 cm ± 0.6 and the maximum post-histotripsy treatment zone diameter was 3.6 cm ± 1.4. Technical success was observed in 42 of 44 treated tumors (95%; 95% CI: 84, 100) and procedure-related major complications were reported in three of 44 participants (7%; 95% CI: 2, 18), both meeting the performance goal. Conclusion The #HOPE4LIVER trials met the co-primary end-point performance goals for technical success and the absence of procedure-related major complications, supporting early clinical adoption. Clinical trial registration nos. NCT04572633, NCT04573881 Published under a CC BY 4.0 license. Supplemental material is available for this article. See also the editorial by Nezami and Georgiades in this issue.

Precise liver tumor ablation: the clinical potential of US-US overlay fusion guidance.

Image-guided thermal ablation is a minimally invasive option for patients with early-stage hepatocellular carcinoma (HCC). However, the risk of local recurrence remains substantial because ultrasound (US) artifacts have a negative impact on the assessment of ablative margins during and immediately after ablation. Precise, real-time assessment of the ablation zone is key to reducing the risk of local tumor progression. With the advent of US image fusion technology, ablative margins can now be assessed three-dimensionally with greater accuracy. Therefore, US-US overlay fusion guidance has the potential to improve the local controllability of ablation in patients with HCC. This review discusses the US-US fusion guidance technique and its current clinical applications for hepatic interventions, with descriptions of its concept, methodology, and efficacy.

Outcomes of radiofrequency ablation for liver tumors in patients on hemodialysis: Results from the US Nationwide Inpatient Sample 2005–2020

ObjectiveFew studies have examined the outcomes of radiofrequency ablation (RFA) for liver tumors in patients on hemodialysis. This study aimed to investigate short-term outcomes following RFA for liver tumors in patients on hemodialysis. MethodsData of patients ≥ 20 years old diagnosed with liver tumors who underwent RFA were extracted from the Nationwide Inpatient Sample (NIS) database 2005–2020. The study population was divided into two groups: patients on hemodialysis and those not on hemodialysis. Propensity score matching (PSM) was employed to address baseline differences. Associations between hemodialysis and in-hospital outcomes, including prolonged length of stay (LOS), in-hospital mortality, unfavorable discharge, and complications were determined using logistic regression analyses. ResultsAfter applying the inclusion and exclusion criteria, a total of 12,749 patients constituted the study population, with 550 remaining after 1:4 PSM (110 on hemodialysis and 440 without hemodialysis). After adjustment in the multivariable analyses, patients on maintenance hemodialysis showed significantly higher risks of prolonged LOS (adjusted odds ratio [aOR] = 2.88, 95 % confidence interval [CI]: 1.78–4.65), in-hospital mortality (aOR=31.90, 95 % CI: 17.68–57.58), unfavorable discharge (aOR=3.79, 95 % CI: 2.05–7.01), at least one complications (aOR=3.68, 95 % CI: 2.49–5.44), and greater total hospital costs (adjusted Beta [aBeta] = 126.75, 95 % CI: 113.68–139.82). ConclusionsPatients on hemodialysis undergoing RFA for liver tumors have greater risks of adverse short-term outcomes including in-hospital mortality, prolonged LOS, complications, and unfavorable discharge. Careful consideration and close monitoring are warranted for patients on hemodialysis when planning for RFA.3

Past, present, and future perspectives of ultrasound-guided ablation of liver tumors: Where could artificial intelligence lead interventional oncology?

The first ablation procedures for small hepatocellular carcinomas were percutaneous ethanol injection under ultrasound (US) guidance. Later, radiofrequency ablation was shown to achieve larger coagulation areas than percutaneous ethanol injection and became the most used ablation technique worldwide. In the past decade, microwave ablation systems have achieved larger ablation areas than radiofrequency ablation, suggesting that the 3-cm barrier could be broken in the treatment of liver tumors. Likewise, US techniques to guide percutaneous ablation have seen important progress. Contrast-enhanced US (CEUS) can define and target the tumor better than US and can assess the size of the ablation area after the procedure, which allows immediate retreatment of the residual tumor foci. Furthermore, fusion imaging fuses real-time US images with computed tomography or magnetic resonance imaging with significant improvements in detecting and targeting lesions with low conspicuity on CEUS. Recently, software powered by artificial intelligence has been developed to allow three-dimensional segmentation and reconstruction of the anatomical structures, aiding in procedure planning, assessing ablation completeness, and targeting the residual viable foci with greater precision than CEUS. Hopefully, this could lead to the ablation of tumors up to 5-7 cm in size.

Particle swarm optimization solution for roll-off control in radiofrequency ablation of liver tumors: Optimal search for PID controller tuning.

The study investigates the efficacy of a bioinspired Particle Swarm Optimization (PSO) approach for PID controller tuning in Radiofrequency Ablation (RFA) for liver tumors. Ex-vivo experiments were conducted, yielding a 9th order continuous-time transfer function. PSO was applied to optimize PID parameters, achieving outstanding simulation results: 0.605% overshoot, 0.314 seconds rise time, and 2.87 seconds settling time for a unit step input. Statistical analysis of 19 simulations revealed PID gains: Kp (mean: 5.86, variance: 4.22, standard deviation: 2.05), Ki (mean: 9.89, variance: 0.048, standard deviation: 0.22), Kd (mean: 0.57, variance: 0.021, standard deviation: 0.14) and ANOVA analysis for the 19 experiments yielded a p-value ≪ 0.05. The bioinspired PSO-based PID controller demonstrated remarkable potential in mitigating roll-off effects during RFA, reducing the risk of incomplete tumor ablation. These findings have significant implications for improving clinical outcomes in hepatocellular carcinoma management, including reduced recurrence rates and minimized collateral damage. The PSO-based PID tuning strategy offers a practical solution to enhance RFA effectiveness, contributing to the advancement of radiofrequency ablation techniques.

Determination of the Optimal Parameters for Microwave Ablation of Liver Tumor

Microwave ablation is a minimally invasive cancer treatment with high survival and low recurrence rates. Despite the unquestionable benefits of microwave ablation, the interaction between the medical tool and the tissue may cause damage to the surrounding tissue, which can be removed by clarifying the conditions for their development. In addition to clinical methods, computer simulation has proven to be a very effective tool to optimize microwave ablation performance. This study aimed to determine the optimal input power for complete microwave tumor ablation with an adequate safety margin while avoiding injury to surrounding healthy tissue. The liver tumor model was based on a real tumor labeled 1.02 in the 3D-IRCADb-01 database. Calculations were performed for a 10-slot microwave antenna with a frequency of 2.45 GHz using COMSOL Multiphysics. The obtained simulation results revealed that with proper input power, the necrotic tissue was mainly located in the tumor with minimal damage to the surrounding healthy tissue. This study may represent a step forward in planning individual microwave ablation procedures for each patient.

Using Patient-Specific 3D Modeling and Simulations to Optimize Microwave Ablation Therapy for Liver Cancer.

Microwave ablation (MWA) of liver tumors presents challenges like under- and over-ablation, potentially leading to inadequate tumor destruction and damage to healthy tissue. This study aims to develop personalized three-dimensional (3D) models to simulate MWA for liver tumors, incorporating patient-specific characteristics. The primary objective is to validate the predicted ablation zones compared to clinical outcomes, offering insights into MWA before therapy to facilitate accurate treatment planning. Contrast-enhanced CT images from three patients were used to create 3D models. The simulations used coupled electromagnetic wave propagation and bioheat transfer to estimate the temperature distribution, predicting tumor destruction and ablation margins. The findings indicate that prolonged ablation does not significantly improve tumor destruction once an adequate margin is achieved, although it increases tissue damage. There was a substantial overlap between the clinical ablation zones and the predicted ablation zones. For patient 1, the Dice score was 0.73, indicating high accuracy, with a sensitivity of 0.72 and a specificity of 0.76. For patient 2, the Dice score was 0.86, with a sensitivity of 0.79 and a specificity of 0.96. For patient 3, the Dice score was 0.8, with a sensitivity of 0.85 and a specificity of 0.74. Patient-specific 3D models demonstrate potential in accurately predicting ablation zones and optimizing MWA treatment strategies.

Design of Path-Planning System for Interventional Thermal Ablation of Liver Tumors Based on CT Images.

Aiming at the shortcomings of artificial surgical path planning for the thermal ablation of liver tumors, such as the time-consuming and labor-consuming process, and relying heavily on doctors' puncture experience, an automatic path-planning system for thermal ablation of liver tumors based on CT images is designed and implemented. The system mainly includes three modules: image segmentation and three-dimensional reconstruction, automatic surgical path planning, and image information management. Through organ segmentation and three- dimensional reconstruction based on CT images, the personalized abdominal spatial anatomical structure of patients is obtained, which is convenient for surgical path planning. The weighted summation method based on clinical constraints and the concept of Pareto optimality are used to solve the multi-objective optimization problem, screen the optimal needle entry path, and realize the automatic planning of the thermal ablation path. The image information database was established to store the information related to the surgical path. In the discussion with clinicians, more than 78% of the paths generated by the planning system were considered to be effective, and the efficiency of system path planning is higher than doctors' planning efficiency. After improvement, the system can be used for the planning of the thermal ablation path of a liver tumor and has certain clinical application value.

Dosimetric comparison of proton therapy and CyberKnife in stereotactic body radiation therapy for liver cancers

Stereotactic body radiation therapy (SBRT) has been increasingly used for the ablation of liver tumours. CyberKnife and proton beam therapy (PBT) are two advanced treatment technologies suitable to deliver SBRT with high dose conformity and steep dose gradients. However, there is very limited data comparing the dosimetric characteristics of CyberKnife to PBT for liver SBRT. PBT and CyberKnife plans were retrospectively generated using 4DCT datasets of ten patients who were previously treated for hepatocellular carcinoma (HCC, N = 5) and liver metastasis (N = 5). Dose volume histogram data was assessed and compared against selected criteria; given a dose prescription of 54 Gy in 3 fractions for liver metastases and 45 Gy in 3 fractions for HCC, with previously published consensus-based normal tissue dose constraints. Comparison of evaluation parameters showed a statistically significant difference for target volume coverage and liver, lungs and spinal cord (p < 0.05) dose, while chest wall and skin did not indicate a significant difference between the two modalities. A number of optimal normal tissue constraints was violated by both the CyberKnife and proton plans for the same patients due to proximity of tumour to chest wall. PBT resulted in greater organ sparing, the extent of which was mainly dependent on tumour location. Tumours located on the liver periphery experienced the largest increase in organ sparing. Organ sparing for CyberKnife was comparable with PBT for small target volumes.

Ablation of liver tumors : From pre-interventional imaging to post-interventional assessment

The aim of this article is to provide an overview on the most frequently applied image-guided, percutaneous, local ablative techniques for treatment of primary and secondary liver tumors. The technical procedures of microwave ablation (MWA) and radiofrequency ablation (RFA) are presented. The pre-interventional diagnostics, indications and feasibility are also discussed, taking the current national guidelines into consideration. Finally, treatment outcomes and recommendations on post-interventional imaging following local tumor ablation are presented.

Conventional versus Hepatic Arteriography and C-Arm CT-Guided Ablation of Liver Tumors (HepACAGA): A Comparative Analysis.

Hepatic Arteriography and C-Arm CT-Guided Ablation of liver tumors (HepACAGA) is a novel technique, combining hepatic-arterial contrast injection with C-arm CT-guided navigation. This study compared the outcomes of the HepACAGA technique with patients treated with conventional ultrasound (US) and/or CT-guided ablation. In this retrospective cohort study, all consecutive patients with hepatocellular carcinoma (HCC) or colorectal liver metastases (CRLM) treated with conventional US-/CT-guided ablation between 1 January 2015, and 31 December 2020, and patients treated with HepACAGA between 1 January 2021, and 31 October 2023, were included. The primary outcome was local tumor recurrence-free survival (LTRFS). Secondary outcomes included the local tumor recurrence (LTR) rate and complication rate. 68 patients (120 tumors) were included in the HepACAGA cohort and 53 patients (78 tumors) were included in the conventional cohort. In both cohorts, HCC was the predominant tumor type (63% and 73%, respectively). In the HepACAGA cohort, all patients received microwave ablation. Radiofrequency ablation was the main ablation technique in the conventional group (78%). LTRFS was significantly longer for patients treated with the HepACAGA technique (p = 0.015). Both LTR and the complication rate were significantly lower in the HepACAGA cohort compared to the conventional cohort (LTR 5% vs. 26%, respectively; p < 0.001) (complication rate 4% vs. 15%, respectively; p = 0.041). In this study, the HepACAGA technique was safer and more effective than conventional ablation for HCC and CRLM, resulting in lower rates of local tumor recurrence, longer local tumor recurrence-free survival and fewer procedure-related complications.

Robotic Assistance in Percutaneous Liver Ablation Therapies: A Systematic Review and Meta-Analysis.

The aim of this systematic review and meta-analysis is to identify current robotic assistance systems for percutaneous liver ablations, compare approaches, and determine how to achieve standardization of procedural concepts for optimized ablation outcomes. Image-guided surgical approaches are increasingly common. Assistance by navigation and robotic systems allows to optimize procedural accuracy, with the aim to consistently obtain adequate ablation volumes. Several databases (PubMed/MEDLINE, ProQuest, Science Direct, Research Rabbit, and IEEE Xplore) were systematically searched for robotic preclinical and clinical percutaneous liver ablation studies, and relevant original manuscripts were included according to the Preferred Reporting items for Systematic Reviews and Meta-Analyses guidelines. The endpoints were the type of device, insertion technique (freehand or robotic), planning, execution, and confirmation of the procedure. A meta-analysis was performed, including comparative studies of freehand and robotic techniques in terms of radiation dose, accuracy, and Euclidean error. The inclusion criteria were met by 33/755 studies. There were 24 robotic devices reported for percutaneous liver surgery. The most used were the MAXIO robot (8/33; 24.2%), Zerobot, and AcuBot (each 2/33, 6.1%). The most common tracking system was optical (25/33, 75.8%). In the meta-analysis, the robotic approach was superior to the freehand technique in terms of individual radiation (0.5582, 95% confidence interval [CI] = 0.0167-1.0996, dose-length product range 79-2216 mGy.cm), accuracy (0.6260, 95% CI = 0.1423-1.1097), and Euclidean error (0.8189, 95% CI = -0.1020 to 1.7399). Robotic assistance in percutaneous ablation for liver tumors achieves superior results and reduces errors compared with manual applicator insertion. Standardization of concepts and reporting is necessary and suggested to facilitate the comparison of the different parameters used to measure liver ablation results. The increasing use of image-guided surgery has encouraged robotic assistance for percutaneous liver ablations. This systematic review analyzed 33 studies and identified 24 robotic devices, with optical tracking prevailing. The meta-analysis favored robotic assessment, showing increased accuracy and reduced errors compared with freehand technique, emphasizing the need for conceptual standardization.

Abstract 1456: First successful engraftment of human liver cancer cell line in highly robust immunocompromised porcine model to test the tumor ablation efficacy by histotripsy

Abstract Liver tumor, commonly called Hepatocellular carcinoma(HCC), is the most common type of primary liver malignancy. It is the fourth leading cause of cancer-related deaths. Late diagnosis, location of the tumor, tumor burden, and metastases makes liver tumor very challenging to treat by liver transplantation, surgical procedures, and other ablation techniques like cryoablation and thermal ablation. Also, the absence of a preclinical animal model makes it challenging to develop and explore the feasibility of treatment modalities. Histotripsy is a non-invasive, non-ionizing, non-thermal, image-guided focused ultrasound ablation treatment method that uses high-pressure pulses to create acoustic cavitation, a “bubble cloud,” at the target. The bubble cloud expands and collapses, which ablates the tissue into an acellular homogenate. Pigs are ideal animal models as they closely resemble human anatomy and are significant in improving the translation to human patients. This study aimed to establish the feasibility of successfully ablating liver tumors by histotripsy using an immunocompromised porcine model to generate HepG2 human liver cancer cell line tumors in the liver of the immunocompromised pigs. The orthotopic porcine model was established using RAG2/IL2RG double knockout immunocompromised pigs. HepG2 cells were injected orthotopically into the liver of immunocompromised pigs. Three weeks after the injections, CT images and necropsy indicated successful engraftment and growth of liver tumors in the pigs. The ultrasound images and post-histotripsy treatment histology images showed confirmed ablation zones in the liver. Therefore, in conclusion, our preliminary results in the study could demonstrate, for the first time, a highly robust model of human liver cancer in a large animal model. Soon, we plan to conduct more such studies and explore all the possible utilities of these immunocompromised porcine models to develop therapeutic strategies to increase the efficacy of liver tumor ablation by histotripsy. Citation Format: Tamalika Paul, Khan M. Imran, Jessica Gannon, Brie Trusiano, Kristin Eden, Hannah Ivester, Madeline Mott, Manali Powar, Michael Edwards, Christopher Byron, Sherrie Clark-Deener, Kiho Lee, Eli Vlaisavljevich, Irving Coy Allen. First successful engraftment of human liver cancer cell line in highly robust immunocompromised porcine model to test the tumor ablation efficacy by histotripsy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1456.

The Added Value of Transcatheter CT Hepatic Angiography (CTHA) Image Guidance in Percutaneous Thermal Liver Ablation: An Experts' Opinion Pictorial Essay.

With the rapidly evolving field of image-guided tumor ablation, there is an increasing demand and need for tools to optimize treatment success. Known factors affecting the success of (non-)thermal liver ablation procedures are the ability to optimize tumor and surrounding critical structure visualization, ablation applicator targeting, and ablation zone confirmation. A recent study showed superior local tumor progression-free survival and local control outcomes when using transcatheter computed tomography hepatic angiography (CTHA) guidance in percutaneous liver ablation procedures. This pictorial review provides eight clinical cases from three institutions, MD Anderson (Houston, TX, USA), Gustave Roussy (Paris, France), and Amsterdam UMC (Amsterdam, The Netherlands), with the intent to demonstrate the added value of real-time CTHA guided tumor ablation for primary liver tumors and liver-only metastatic disease. The clinical illustrations highlight the ability to improve the detectability of the initial target liver tumor(s) and identify surrounding critical vascular structures, detect 'vanished' and/or additional tumors intraprocedurally, differentiate local tumor progression from non-enhancing scar tissue, and promptly detect and respond to iatrogenic hemorrhagic events. Although at the cost of adding a minor but safe intervention, CTHA-guided liver tumor ablation minimizes complications of the actual ablation procedure, reduces the number of repeat ablations, and improves the oncological outcome of patients with liver malignancies. Therefore, we recommend adopting CTHA as a potential quality-improving guiding method within the (inter)national standards of practice.

A comparison of three different microwave systems for laparoscopic liver tumor ablation.

Our aim was to perform a comparison of three current microwave ablation (MWA) systems widely used for laparoscopic liver ablations in terms of ablation kinetics and geometry of ablation zones. This was a retrospective, institutional review board-approved study comparing Emprint, Emprint HP, and NeuWave systems for laparoscopic liver ablation. Analyses were performed via Mann-Whitney U and χ2tests. Continuous data are presented as median (interquartile range). For Emprint, Emprint HP, and NeuWave groups, tumor size was 1.16 (0.8), 1.21 (0.7), and 1.27 (0.9) cm(p = 0.54). Ablation time per lesion was 7 (6), 4 (2.8), and 4 (3.3) min(p < 0.0001), yielding similar ablation zone volumes and margins. The time to first ablation bubble was 1 (0.13), 1.5 (0.85), and 0.75 (0.5) min, and total ablation times were 7 (4.4), 4 (2), and 3.5 (2.8) min(p < 0.0001). The roundness index A, B, and transverse were 0.94, 0.98, and 0.79; 0.95, 0.95, and 0.78; and 1.02, 0.95, and 0.96. Although a saline-cooling system with Emprint system allowed for larger diameter spherical ablation zones to be created, it led to decreased efficiency compared to the CO2-cooled NeuWave system, which exposes the active antenna directly to tissue. Increased power delivered by Emprint HP improved the efficiency of saline-cooled design, as demonstrated by faster ablation times.