AGA Clinical Practice Guideline on Endoscopic Eradication Therapy of Barrett's Esophagus and Related Neoplasia.

BACKGROUND & AIMS: Barrett's esophagus (BE) is the precursor to esophageal adenocarcinoma (EAC). Endoscopic eradication therapy (EET) can be effective in eradicating BE and related neoplasia and has greater risk of harms and resource use than surveillance endoscopy. This clinical practice guideline aims to inform clinicians and patients by providing evidence-based practice recommendations for the use of EET in BE and related neoplasia. METHODS: The Grading of Recommendations Assessment, Development and Evaluation framework was used to assess evidence and make recommendations. The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients, conducted an evidence review, and used the Evidence-to-Decision Framework to develop recommendations regarding the use of EET in patients with BE under the following scenarios: presence of (1) high-grade dysplasia, (2) low-grade dysplasia, (3) no dysplasia, and (4) choice of stepwise endoscopic mucosal resection (EMR) or focal EMR plus ablation, and (5) endoscopic submucosal dissection vs EMR. Clinical recommendations were based on the balance between desirable and undesirable effects, patient values, costs, and health equity considerations. RESULTS: The panel agreed on 5 recommendations for the use of EET in BE and related neoplasia. Based on the available evidence, the panel made a strong recommendation in favor of EET in patients with BE high-grade dysplasia and conditional recommendation against EET in BE without dysplasia. The panel made a conditional recommendation in favor of EET in BE low-grade dysplasia; patients with BE low-grade dysplasia who place a higher value on the potential harms and lower value on the benefits (which are uncertain) regarding reduction of esophageal cancer mortality could reasonably select surveillance endoscopy. In patients with visible lesions, a conditional recommendation was made in favor of focal EMR plus ablation over stepwise EMR. In patients with visible neoplastic lesions undergoing resection, the use of either endoscopic mucosal resection or endoscopic submucosal dissection was suggested based on lesion characteristics. CONCLUSIONS: This document provides a comprehensive outline of the indications for EET in the management of BE and related neoplasia. Guidance is also provided regarding the considerations surrounding implementation of EET. Providers should engage in shared decision making based on patient preferences. Limitations and gaps in the evidence are highlighted to guide future research opportunities.

Aquablation versus HoLEP in patients with benign prostatic hyperplasia: a comparative prospective non-randomized study.

PURPOSE: The question of best surgical treatment for lower urinary tract symptoms (LUTS) due to benign prostate hyperplasia (BPH) remains controversial. We compared the outcomes of aquablation and holmium laser enucleation of the prostate ("HoLEP") in a prospective cohort. METHODS: Patients with BPH underwent aquablation or HoLEP according to their preference between June 2020 and April 2022. Prostate volume ("PV"), laboratory results, postvoid residual volume, uroflowmetry, IPSS, ICIQ-SF, MSHQ-EjD, EES and IIEF were evaluated preoperatively and at three, six and 12 months postoperatively. We also analyzed perioperative characteristics and complications via the Clavien Dindo ("CD") classification. RESULTS: We included 40 patients, 16 of whom underwent aquablation and 24 HoLEP. Mean age was 67 years (SD 7.4). Baseline characteristics were balanced across groups, except the HoLEP patients' larger PV. IPSS fell from 20.3 (SD 7.1) at baseline to 6.3 (SD 4.2) at 12 months (p < 0.001) without differences between aquablation and HoLEP. HoLEP was associated with shorter operation time (59.5 (SD 18.6) vs. 87.2 (SD 14.8) minutes, p < 0.001) and led to better PV reduction over all timepoints. At three months, aquablation's results were better regarding ejaculatory (p = 0.02, MSHQ-EjD) and continence function (p < 0.001, ICIQ-SF). Beyond three months, erectile, ejaculatory, continence function and LUTS reduction did not differ significantly between aquablation and HoLEP. CD ≥ grade 3b complications were noted in six patients in aquablation group while only one in HoLEP group (p = < 0.01). CONCLUSIONS: While aquablation revealed temporary benefits regarding ejaculation and continence at three months, HoLEP was superior concerning operation time, the safety profile and volumetric results.

Assessing the relative effectiveness of various ultrasound-guided ablation techniques for treating benign thyroid nodules: A systematic review and network meta-analysis.

BACKGROUND: Benign thyroid nodules (BTNs) represent a prevalent clinical challenge globally, with various ultrasound-guided ablation techniques developed for their management. Despite the availability of these methods, a comprehensive evaluation to identify the most effective technique remains absent. This study endeavors to bridge this knowledge gap through a network meta-analysis (NMA), aiming to enhance the understanding of the comparative effectiveness of different ultrasound-guided ablation methods in treating BTNs. METHODS: We comprehensively searched PubMed, Embase, Cochrane, Web of Science, Ovid, SCOPUS, and ProQuest for studies involving 16 ablation methods, control groups, and head-to-head trials. NMA was utilized to evaluate methods based on the percentage change in nodule volume, symptom score, and cosmetic score. This study is registered in INPLASY (registration number 202260061). RESULTS: Among 35 eligible studies involving 5655 patients, NMA indicated that RFA2 (radiofrequency ablation, 2 sessions) exhibited the best outcomes at 6 months for percentage change in BTN volume (SUCRA value 74.6), closely followed by RFA (SUCRA value 73.7). At 12 months, RFA was identified as the most effective (SUCRA value 81.3). Subgroup analysis showed RFA2 as the most effective for solid nodule volume reduction at 6 months (SUCRA value 75.6), and polidocanol ablation for cystic nodules (SUCRA value 66.5). CONCLUSION: Various ablation methods are effective in treating BTNs, with RFA showing notable advantages. RFA with 2 sessions is particularly optimal for solid BTNs, while polidocanol ablation stands out for cystic nodules.

Sex-Related Differences in Patients With Hypertrophic Cardiomyopathy Undergoing Alcohol Septal Ablation.

BACKGROUND: Previous studies have shown that women with hypertrophic obstructive cardiomyopathy (HCM) have worse long-term outcomes irrespective of intervention. However, the outcomes of patients undergoing alcohol septal ablation (ASA) based on sex have not been described. Hence, this study aimed to evaluate pressure changes and long-term mortality in patients with HCM undergoing ASA based on sex. METHODS AND RESULTS: This is a single-center retrospective study evaluating hemodynamic changes and long-term mortality in patients with HCM treated with ASA according to sex. A total of 259 patients were included (aged 68.4±11.9 years, 62.2% women). Women had higher age and baseline pressures at the time of ASA, with a greater percent reduction in mean left atrial pressure (men versus women: 2.2% versus 15.9%, respectively; P=0.02). Women had better survival (median survival rate of men versus women: 8.6 versus 12.5 years, respectively; P=0.011). On Cox multivariable regression, predictors of mortality were age (per group change <60 years, 61-70 years, 71-80 years, and >80 years; hazard ratio [HR], 1.45 [95% CI, 1.10-1.91], P=0.008), female sex (HR, 0.59 [95% CI, 0.35-0.99], P=0.048), chronic kidney disease (HR, 1.88 [95% CI, 1.06-3.33], P=0.031), and left ventricular outflow tract gradient reduction ≤86% (HR, 1.91 [95% CI, 1.14-3.19], P=0.014). CONCLUSIONS: Women with HCM undergoing ASA are older and have higher left-sided baseline pressures compared with men yet have better survival. Further studies exploring the mechanisms of differential outcomes according to sex in patients with HCM undergoing ASA are needed.

Clinical safety and efficacy of microwave ablation for small renal masses.

PURPOSE: CT-guided MWA is a safe and effective tool that should be utilized in the treatment of small renal masses (SRMs). We aim to clarify the utility of CT-guided MWA by examining patient outcomes such as recurrence, treatment success, changes in renal function, and complications. METHODS: A retrospective review of consecutive patients with SRMs who underwent same day renal mass biopsy (RMB) and CT-guided MWA between 2015 and 2022 was performed. Treatment safety was assessed by 30-day complications according to the Clavien-Dindo system and change in eGFR >30 days post-procedure. Treatment efficacy was defined by local recurrence and incomplete treatment rates and calculated using the Kaplan-Meier method. RESULTS: A total of 108 renal masses were found in 104 patients. The overall complication rate was 7.4% (8/108), of which 4 were major complications (3.7%). For those with renal function available >30 days post ablation, the median eGFR was 47.2 (IQR: 36.0, 57), compared to 52.3 (IQR: 43.7, 61.5) pre-ablation, p<0.0001. 5-year local recurrence free survival was 86%. Among those with biopsy proven malignancy (n= 66), there were five local recurrences (7.54%) occurring at a median of 25.1 months (IQR 19.9, 36.2) and one case (1.5%) of incomplete treatment. CONCLUSIONS: As the medical field continues to evolve towards less invasive interventions, MWA offers a valuable tool in the management of renal masses. With low major complication and recurrence rates, our findings support the utility of CT-guided MWA as a tool for treatment of SRMs.

Advances in Tumor Management: Harnessing the Potential of Histotripsy.

Tissue ablation techniques have long been used in clinical settings to treat various oncologic diseases. However, many of these techniques are invasive and can cause substantial adverse effects. Histotripsy is a noninvasive, nonionizing, nonthermal tissue ablation technique that has the potential to replace surgical interventions in various clinical settings. Histotripsy works by delivering high-intensity focused ultrasound waves to target tissue. These waves create cavitation bubbles within tissues that rapidly expand and collapse, thereby mechanically fractionating the tissue into acellular debris that is subsequently absorbed by the body's immune system. Preclinical and clinical studies have demonstrated the efficacy of histotripsy in treating a range of diseases, including liver, pancreatic, renal, and prostate tumors. Safety outcomes of histotripsy have been generally favorable, with minimal adverse effects reported. However, further studies are needed to optimize the technique and understand its long-term effects. This review aims to discuss the importance of histotripsy as a noninvasive tissue ablation technique, the preclinical and clinical literature on histotripsy and its safety, and the potential applications of histotripsy in clinical practice. Keywords: Tumor Microenvironment, Ultrasound-High-Intensity Focused (HIFU), Ablation Techniques, Abdomen/GI, Genital/Reproductive, Nonthermal Tissue Ablation, Histotripsy, Clinical Trials, Preclinical Applications, Focused Ultrasound © RSNA, 2024.

Hepatic Ablation Technology: Assessment of Conflicts of Interest in Recent Literature.

INTRODUCTION: Collaboration between the health care industry and surgeons is critical in modern medicine. Conflict of interest (COI) has the risk of introducing bias into research studies. We investigated the accuracy of self-disclosed COI for studies that researched the use of microwave ablation for liver metastasis. METHODS: A literature search identified studies that investigated the use of microwave ablation for liver cancer between 2016 and 2022. We utilized the Open Payments Database to query individual authors' financial contributions from the industry. The accuracy of the disclosure statement and financial contribution for each study and author was calculated. We compared the amount of financial contribution authors received based on the accuracy of their COI statement. RESULTS: Twenty-five studies of interest were identified. The mean number of authors was 8.24. A disclosure statement was present in 52% of studies. Of those, 28% had an incongruent disclosure statement. 9/25 (36%) of studies had a conflict of interest based on financial payments provided by industry. Overall, authors received an average of $440,483.41 (SD $1,889,375.34). We did not find a difference in the financial contribution's value based on the disclosure statement's accuracy (P = .55). CONCLUSIONS: Over a quarter of studies in our review of microwave ablation literature had discrepancies in the reporting of conflicts of interest, highlighting the need for improved reporting of potential conflicts of interest to protect the integrity of clinical research. Compared to other fields of surgery, we found a lower rate of undisclosed COI, suggesting that the scope of cancer-directed surgery may be more resistant to industry influence.

Thermometry mapping during CT-guided thermal ablations: proof of feasibility and internal validation using spectral CT.

Objective. Conventional computed tomography (CT) imaging does not provide quantitative information on local thermal changes during percutaneous ablative therapy of cancerous and benign tumors, aside from few qualitative, visual cues. In this study, we have investigated changes in CT signal across a wide range of temperatures and two physical phases for two different tissue mimicking materials, each.Approach. A series of experiments were conducted using an anthropomorphic phantom filled with water-based gel and olive oil, respectively. Multiple, clinically used ablation devices were applied to locally cool or heat the phantom material and were arranged in a configuration that produced thermal changes in regions with inconsequential amounts of metal artifact. Eight fiber optic thermal sensors were positioned in the region absent of metal artifact and were used to record local temperatures throughout the experiments. A spectral CT scanner was used to periodically acquire and generate electron density weighted images. Average electron density weighted values in 1 mm3volumes of interest near the temperature sensors were computed and these data were then used to calculate thermal volumetric expansion coefficients for each material and phase.Main results. The experimentally determined expansion coefficients well-matched existing published values and variations with temperature-maximally differing by 5% of the known value. As a proof of concept, a CT-generated temperature map was produced during a heating time point of the water-based gel phantom, demonstrating the capability to map changes in electron density weighted signal to temperature.Significance. This study has demonstrated that spectral CT can be used to estimate local temperature changes for different materials and phases across temperature ranges produced by thermal ablations.

Clinical characteristics and outcomes of alcohol septal ablation in the era of transcatheter valve interventions.

BACKGROUND: The clinical efficacy and safety of alcohol septal ablation (ASA) for obstructive hypertrophic cardiomyopathy (HCM) have been well-established; however, less is known about outcomes in patients undergoing preemptive ASA before transcatheter mitral valve replacement (TMVR). AIMS: The goal of this study is to characterize the procedural characteristics and examine the clinical outcomes of ASA in both HCM and pre-TMVR. METHODS: This retrospective study compared procedural characteristics and outcomes in patient who underwent ASA for HCM and TMVR. RESULTS: In total, 137 patients were included, 86 in the HCM group and 51 in the TMVR group. The intraventricular septal thickness (mean 1.8 vs. 1.2 cm; p < 0.0001) and the pre-ASA LVOT gradient (73.6 vs. 33.8 mmHg; p ≤ 0.001) were higher in the HCM group vs the TMVR group. The mean volume of ethanol injected was higher (mean 2.4 vs. 1.7 cc; p < 0.0001). The average neo-left ventricular outflow tract area increased significantly after ASA in the patients undergoing TMVR (99.2 ± 83.37 mm2 vs. 196.5 ± 114.55 mm2; p = <0.0001). The HCM group had a greater reduction in the LVOT gradient after ASA vs the TMVR group (49.3 vs. 18 mmHg; p = 0.0040). The primary composite endpoint was higher in the TMVR group versus the HCM group (50.9% vs. 25.6%; p = 0.0404) and had a higher incidence of new permanent pacemaker (PPM) (25.5% vs. 18.6%; p = 0.3402). The TMVR group had a higher rate of all-cause mortality (9.8% vs. 1.2%; p = 0.0268). CONCLUSIONS: Preemptive ASA before TMVR was performed in patients with higher degree of clinical comorbidities, and correspondingly is associated with worse short-term clinical outcomes in comparison to ASA for HCM patients. ASA before TMVR enabled percutaneous mitral interventions in a small but significant minority of patients that would have otherwise been excluded. The degree of LVOT and neoLVOT area increase is significant and predictable.

Does radiofrequency ablation procedural data improve the accuracy of identifying atrial fibrillation recurrence?

Radiofrequency ablation (RFA) using the CARTO 3D mapping system is a common approach for pulmonary vein isolation to treat atrial fibrillation (AF). Linkage between CARTO procedural data and patients' electronical health records (EHR) provides an opportunity to identify the ablation-related parameters that would predict AF recurrence. The objective of this study is to assess the incremental accuracy of RFA procedural data to predict post-ablation AF recurrence using machine learning model. Procedural data generated during RFA procedure were downloaded from CARTONET and linked to deidentified Mercy Health EHR data. Data were divided into train (70%) and test (30%) data for model development and validation. Automate machine learning (AutoML) was used to predict 1 year AF recurrence, defined as a composite of repeat ablation, electrical cardioversion, and AF hospitalization. At first, AutoML model only included Patients' demographic and clinical characteristics. Second, an AutoML model with procedural variables and demographical/clinical variables was developed. Area under receiver operating characteristic curve (AUROC) and net reclassification improvement (NRI) were used to compare model performances using test data. Among 306 patients, 67 (21.9%) patients experienced 1-year AF recurrence. AUROC increased from 0.66 to 0.78 after adding procedural data in the AutoML model based on test data. For patients with AF recurrence, NRI was 32% for model with procedural data. Nine of 10 important predictive features were CARTO procedural data. From CARTO procedural data, patients with lower contact force in right inferior site, long ablation duration, and low number of left inferior and right roof lesions had a higher risk of AF recurrence. Patients with persistent AF were more likely to have AF recurrence. The machine learning model with procedural data better predicted 1-year AF recurrence than the model without procedural data. The model could be used for identification of patients with high risk of AF recurrence post ablation.

Ablation of Kidney Tumors in Patients with Substantial Kidney Impairment: Current Status.

PURPOSE OF REVIEW: To review the current status of kidney tumor ablation in patients with substantial kidney impairment. RECENT FINDINGS: Few reports of kidney tumor ablation in such patients have recently been published. The reported prevalence of patients with stage 4 or 5 chronic kidney disease (CKD) among patients undergoing ablation is 2.0%-10%. In patients with stage 4 or 5 CKD, local tumor control rates were 88%-100%. The effect of ablation on CKD stage is unclear, and the observed deteriorations in kidney function are consistent with both the effect of cryoablation and the natural course of advanced CKD. According to guidelines, active surveillance may be selected. The goals of treatment are complete tumor removal and maintenance of kidney function, both of which can be met by ablation. Given the limited treatment options, ablation may play a pivotal role in the management of patients with advanced CKD.

Development of non-invasive flexible directional microwave ablation for central lung cancer: a simulation study.

Transbronchial microwave ablation (MWA) with flexible antennas has gradually become an attractive alternative to percutaneous MWA for lung cancer due to its characteristic of non-invasiveness. However, flexible antennas for the precision ablation of lung tumors that are adjacent to critical bronchial structures are still not available. In this study, a non-invasive flexible directional (FD) antenna for early stage central lung tumors surrounding the bronchia was proposed. A comprehensive numerical MWA model with the FD antenna was developed in a real human-sized left lung model. The structure of the antenna and the treatment protocol were optimized by a generic algorithm for the precision ablation of two cases of early stage central lung cancer (i.e. spherical-like and ellipsoidal tumors). The electromagnetic efficiency of the optimized antenna was also improved by implementing an optimizedπ-matching network for impedance matching. The results indicate that the electromagnetic energy of MWA can be restricted to a particular area for precision ablation of specific lung tumors using the FD antenna. This study contributes to the field of lung cancer management with MWA.

Interaction Between Microbubbles and Microwave Ablation: A Phantom and Rabbit Model.

OBJECTIVES: This study aimed to explore the interactions between microbubbles and microwave ablation (MWA). METHODS: The study employed custom-made phantoms (in vitro) and white New Zealand rabbits (in vivo). MWA was performed with or without microbubbles in the phantoms (2 × 105 particles mL-1) and rabbit livers (intravenous injection of 0.05 mL/kg SonoVue). During the MWA, K-type thermocouple probes were used to monitor the MWA-induced temperature increase. Contrast-enhanced ultrasound imaging (CEUS) was used to monitor and analyze the microbubbles signal intensity. After MWA, the ablation-zone volumes were evaluated and compared between the groups with and without microbubbles. RESULTS: In both the phantom models and rabbits, microbubbles showed no significant influence on MWA, including the ablation range and MWA-induced temperature increase. In phantoms and rabbit livers filled with microbubbles, MWA caused the formation of a gradually expanding microbubble-defect region over the ablation time. An increase in the temperature caused microbubble destruction. CONCLUSIONS: Microbubbles had no significant influence on MWA. However, MWA induced the destruction of microbubbles in a temperature-dependent manner. Thus, the poor thermotolerance of microbubbles is a non-negligible barrier when using CEUS to monitor the ablation range during MWA in real-time.

Percutaneous interstitial brachytherapy ablation for targeting oligometastatic gynecologic cancers.

INTRODUCTION: Treatment of recurrent oligometastatic gynecologic malignancy may involve targeted surgery, thermal ablation, or CT-guided high-dose-rate interstitial brachytherapy ablation (CT-HDR-IBTA). The purpose of this study was to describe the safety and efficacy of CT-HDR-IBTA for oligometastatic gynecologic malignancies. METHODS: With institutional review board approval (IRB) approval and compliance with the Health Insurance Portability and Accountability Act of 1996 (HIPAA) compliance, we searched our database to assemble a single-arm study cohort of all patients with oligometastatic gynecologic cancers who underwent CT-HDR-IBTA from 2012-2022 with follow-up. The electronic record was reviewed to determine relevant clinicopathological variables including patient demographics, prior treatments, clinical course, local control, and local and distant recurrence with follow-up imaging. RESULTS: The study cohort comprised 37 lesions in 34 patients treated with CT-HDR-IBTA for recurrent oligometastatic uterine (n = 17), cervix (n = 1), or ovarian cancer (n = 16) with an average lesion size of 2.5 cm with an average patient age of 61.4 years. Each lesion was treated with an average radiation dose of 23.8 Gy in 1.8 fractions and a median follow-up time of 24.0 months. The primary efficacy of CT HDR ITBA was 73% with a median progression-free survival of 8.0 months (95% CI 3.6-12.8 months) and with 58% of patients still alive at 43 months with median overall survival not reached. The rate of Grade 1 adverse events was 22% without any Grade 2, 3 or 4 events. CONCLUSIONS: CT HDR IBTA was safe and effective for treating oligometastatic gynecologic cancers in a heavily pretreated cohort.

Cox model risk score to predict survival of intrahepatic cholangiocarcinoma after ultrasound-guided ablation.

PURPOSE: To explore factors associated with overall survival (OS) and progression-free survival (PFS) of intrahepatic cholangiocarcinoma (iCCA) after ultrasound-guided ablation and establish a model for survival risk evaluation. METHODS: Data from 54 patients with 86 iCCAs between August 2008 and October 2022 were retrospectively analyzed. Cox regression were used to analyze the effects of clinical features on OS and PFS. Based on the variables screened by multivariable analysis, a model was established to predict the survival of the patients. Time-dependent receiver operating characteristic (timeROC) curve was constructed to evaluate the performance of this model. The model was further verified by bootstrap validation. The clinical usefulness of the model was evaluated by the decision curve analysis (DCA). RESULTS: During follow up, 39 patients died and 49 patients developed recurrence. Pre-ablation CA199 level > 140 U/ml was the only independent predictor of poor PFS. Age > 70 years, early recurrence, maximal diameter of tumor size > 1.5 cm and pre-ablation CA199 level > 140 U/ml were significantly associated with poor OS. Then a model was established based on the above four variables. The areas under the timeROC curve (AUC) for 1-year, 2-year, 3-year, 5-year were 0.767, 0.854, 0.791 and 0.848, respectively. After bootstrapping for 1000 repetitions, the AUCs were similar to the initial model. DCA also demonstrated that the model had good positive net benefits. CONCLUSION: The established model in this study could predict the survival outcomes of the patients with iCCA after thermal ablation, but further research was needed to validate the results.

The influence of microwave ablation parameters on the positioning of trocar in different cancerous tissues: a numerical study.

The present study analyzed the microwave ablation of cancerous tumors located in six major cancer-prone organs and estimated the significance of input power and treatment time parameters in the apt positioning of the trocar into the tissue during microwave ablation. The present study has considered a three-dimensional two-compartment tumour-embedded tissue model. FEA based COMSOL Multiphysics software with inbuilt bioheat transfer, electromagnetic waves, heat transfer in solids and fluids, and laminar flow physics has been used to obtain the numerical results. Based on the mortality rates caused by cancer, the present study has considered six major organs affected by cancer, viz. lung, breast, stomach/gastric, liver, liver (with colon metastasis), and kidney for MWA analysis. The input power (100 W) and ablation times (4 minutes) with apt and inapt positioning of the trocar have been considered to compare the ablation volume of various cancerous tissues. The present study addresses one of the major problems clinicians face, i.e. the proper placement of the trocar due to poor imaging techniques and human error, resulting in incomplete tumor ablation and increased surgical procedures. The highest values of the ablation region have been observed for the liver, colon metastatic liver and breast cancerous tissues compared with other organs at the same operating conditions.

The present study has investigated the application of microwave ablation for cancer treatment in six major organs, specifically emphasizing the evaluation of ablation volume during the procedure. Using COMSOL-Multiphysics software, the study has investigated MWA of tumor embedded organs in the lung, breast, stomach, liver, and kidney. The positioning of the trocar, a crucial element in the treatment process, has been examined to address challenges in effectively ablating tumors.From the results, it has been revealed that liver, colon metastatic liver, and breast cancer tissues exhibited the largest areas of ablation volume compared with other organs.Organs like the breast and hepatic glands, characterized by lower heat capacity and density, have shown larger ablation zones. Trocar positioning significantly influenced the stomach, liver, and kidney, where improper placement led to notable increases in ablation volume, posing a risk of unintended damage to healthy tissue.Further, the study has concluded that precise trocar positioning plays a crucial role in optimizing microwave ablation. This precision has the potential to enhance the effectiveness of cancer treatments while minimizing harm to healthy tissue. The insights gained from this research offer valuable information for clinicians looking to enhance the precision of cancer therapies, ultimately aiming for improved outcomes for patients.

Superparamagnetic iron oxide nanoparticle enhanced percutaneous microwave ablation: Ex-vivo characterization using magnetic resonance thermometry.

BACKGROUND: Percutaneous microwave ablation (pMWA) is a minimally invasive procedure that uses a microwave antenna placed at the tip of a needle to induce lethal tissue heating. It can treat cancer and other diseases with lower morbidity than conventional surgery, but one major limitation is the lack of control over the heating region around the ablation needle. Superparamagnetic iron oxide nanoparticles have the potential to enhance and control pMWA heating due to their ability to absorb microwave energy and their ease of local delivery. PURPOSE: The purpose of this study is to experimentally quantify the capabilities of FDA-approved superparamagnetic iron oxide Feraheme nanoparticles (FHNPs) to enhance and control pMWA heating. This study aims to determine the effectiveness of locally injected FHNPs in increasing the maximum temperature during pMWA and to investigate the ability of FHNPs to create a controlled ablation zone around the pMWA needle. METHODS: PMWA was performed using a clinical ablation system at 915 MHz in ex-vivo porcine liver tissues. Prior to ablation, 50 uL 5 mg/mL FHNP injections were made on one side of the pMWA needle via a 23-gauge needle. Local temperatures at the FHNP injection site were directly compared to equidistant control sites without FHNP. First, temperatures were compared using directly inserted thermocouples. Next, temperatures were measured non-invasively using magnetic resonance thermometry (MRT), which enabled comprehensive four-dimensional (volumetric and temporal) assessment of heating effects relative to nanoparticle distribution, which was quantified using dual-echo ultrashort echo time (UTE) subtraction MR imaging. Maximum heating within FHNP-exposed tissues versus control tissues were compared at multiple pMWA energy delivery settings. The ability to generate a controlled asymmetric ablation zone using multiple FHNP injections was also tested. Finally, intra-procedural MRT-derived heat maps were correlated with gold standard gross pathology using Dice similarity analysis. RESULTS: Maximum temperatures at the FHNP injection site were significantly higher than control (without FHNP) sites when measured using direct thermocouples (93.1 ± 6.0°C vs. 57.2 ± 8.1°C, p = 0.002) and using non-invasive MRT (115.6 ± 13.4°C vs. 49.0 ± 10.6°C, p = 0.02). Temperature difference between FHNP-exposed and control sites correlated with total energy deposition: 66.6 ± 17.6°C, 58.1 ± 8.5°C, and 20.8 ± 9.2°C at high (17.5 ± 2.2 kJ), medium (13.6 ± 1.8 kJ), and low (8.8 ± 1.1 kJ) energies, respectively (all pairwise p < 0.05). Each FHNP injection resulted in a nanoparticle distribution within 0.9 ± 0.2 cm radially of the injection site and a local lethal heating zone confined to within 1.1 ± 0.4 cm radially of the injection epicenter. Multiple injections enabled a controllable, asymmetric ablation zone to be generated around the ablation needle, with maximal ablation radius on the FHNP injection side of 1.6 ± 0.2 cm compared to 0.7 ± 0.2 cm on the non-FHNP side (p = 0.02). MRT intra-procedural predicted ablation zone correlated strongly with post procedure gold-standard gross pathology assessment (Dice similarity 0.9). CONCLUSIONS: Locally injected FHNPs significantly enhanced pMWA heating in liver tissues, and were able to control the ablation zone shape around a pMWA needle. MRI and MRT allowed volumetric real-time visualization of both FHNP distribution and FHNP-enhanced pMWA heating that was useful for intra-procedural monitoring. This work strongly supports further development of a FHNP-enhanced pMWA paradigm; as all individual components of this approach are approved for patient use, there is low barrier for clinical translation.

Percutaneous microwave ablation of T1a renal cell carcinomas: A 10-year single-center retrospective review.

INTRODUCTION: Partial nephrectomy is currently the preferred treatment option for T1a renal cell carcinomas (RCC), with nephron-sparing techniques, including microwave ablation, becoming more common in select patients. Primary aims are to document outcomes of microwave ablation for T1a RCCs in an Australian tertiary centre to add to the evidence for its safety and efficacy. METHODS: The prospectively maintained Sir Charles Gairdner Hospital Interventional Radiology database was retrospectively searched for all Renal Microwave ablations completed between June 2012 and February 2022. This database and a combination of hospital programmes including Agfa Impax PACS, Bossnet digital medical record and iSoft Clinical Manager were used to extract the relevant data which was anonymized and entered into an Excel spreadsheet for analysis. RESULTS: Forty-eight patients underwent microwave ablation for 50 tumours. Of these, there were two local and two distant recurrences. A fifth patient had metastases on presentation. Higher local recurrence rates were associated with larger tumour size (P = 0.043). Tumour proximity to the collecting system <4 mm was associated with higher rates of complications (P = 0.020). RENAL scores did not show statistically significant correlation with complications (P = 0.092) or local or distant recurrence. Notably, the study follow-up time was longer than many comparative studies (mean = 2796, ~7.66 years censoring for death and mean = 832 days, ~2.28 years not censoring for death). CONCLUSION: Consistent with the literature, this study further demonstrates that microwave ablation is a safe and efficacious option for treatment of T1a RCC.

Revolutionizing brain interventions: the multifaceted potential of histotripsy.

Histotripsy, a non-thermal ultrasound technique, holds significant promise in various applications within the realm of brain interventions. While its use for treating brain tumors is somewhat limited, focused ultrasound technology has been extensively investigated for a wide range of purposes within the brain, including disrupting the blood-brain barrier, supporting immunotherapy, addressing conditions like essential tremor, Parkinson's disease, Alzheimer's disease, epilepsy, and neuropathic pain. Research findings indicate that histotripsy can reduce tumor cells with fewer pulses, minimizing the risk of bleeding and cellular injury. The use of MRI sequences such as T2 and T2* enhances the evaluation of the effects of histotripsy treatment, facilitating non-invasive assessment of treated areas. Furthermore, histotripsy displays promise in creating precise brain lesions with minimal edema and inflammation, particularly in porcine models, suggesting considerable progress in the treatment of brain lesions. Moreover, studies confirm its feasibility, safety, and effectiveness in treating intracerebral hemorrhage by safely liquefying clots without causing significant harm to surrounding brain tissue., opening exciting possibilities for clinical applications. The development of transcranial MR-guided focused ultrasound systems based on histotripsy represents a significant breakthrough in overcoming the limitations associated with thermal ablation techniques. Histotripsy's ability to efficiently liquefy clots, minimize skull heating, and target shallow lesions near the skull establishes it as a promising alternative for various brain treatments. In conclusion, histotripsy offers diverse potential in the field of brain interventions, encompassing applications ranging from tumor treatment to the management of intracerebral hemorrhage. While challenges such as accurate monitoring and differentiation of treatment effects persist, ongoing research efforts and technological advancements continue to expand the role of histotripsy in both neurology and neurosurgery.