Efficiency Of Microwave Ablation Research Articles

Microwave-Assisted Chemical Ablation (MA-CA): A Novel Microwave-Assisted Tissue Ablation Procedure—Preliminary Assessment of Efficiency

Microwave (MW) ablation is becoming a routine technology in the interventional radiology field. A new approach combining MW ablation and chemical ablation is developed in this paper. The rationale for the development of this Microwave-Assisted Chemical Ablation (MA-CA) technology was to improve the utility of thermal ablation as a minimally invasive treatment for cancer. The experimental conditions for ex vivo bovine liver samples were: A—100 W (120 s) with no addition of ethanol; B—100 W (30 s), wait (60 s) (no power), and 100 W (90 s) with no addition of ethanol; C—100 W (30 s), wait (60 s), 100 W (30 s), and 100 W (60 s) with the addition of 5 mL ethanol; and D—100 W (30 s), wait (60 s), 100 W (30 s), 0 W (30 s) with the addition of 2.5 mL ethanol, and 100 W (60 s) with the addition of 5 mL ethanol (12,000 Joules Total). The results showed that with the use of ethanol, the ablation zone was enlarged and revealed improved sphericity. This novel combination has greater advantages than either technology individually. The objective is to increase the precision and efficiency of MW ablation and to broaden the range of tissues and pathologies that can be treated using this new approach, and to validate the benefits that arise from combining the advantages of MW and chemical ablation in a relevant setting.

Perfluoropentane/apatinib-encapsulated metal-organic framework nanoparticles enhanced the microwave ablation of hepatocellular carcinoma.

Microwave ablation (MWA) is a promising minimally invasive therapy for hepatocellular carcinoma (HCC). However, the efficiency of MWA in treating HCC is evidently limited by the incomplete ablation of large tumors and tumors in high-risk locations. Here we designed an iron-based metal-organic framework nanomedicine (PFP-Apa-MOF) by loading perfluoropentane (PFP) and apatinib (Apa). After being absorbed by HCC, iron could induce ferroptosis. PFP could be activated into bubbles and act as an ultrasound agent for detecting the ablation margin. As an effective antiangiogenic drug, Apa could inhibit tumor residual growth after MWA. The high efficiency of PFP-Apa-MOF was fully demonstrated in vitro and in vivo. The results showed that MWA combined with PFP-Apa-MOF clearly enhanced the ablation efficiency, leading to apparent tumor inhibition, and increased tumor apoptosis and lipid peroxide. PFP-Apa-MOF could play a valuable role in enhancing MWA to achieve better therapeutic efficacy in HCC.

A Study of Microwave Ablation With Hollow Antenna

To solve the problem of the non-spherical ablation zone in microwave ablation, we propose a hollow microwave ablation antenna. Compared with the microwave ablation antenna with coaxial cable as the main body, we use a hollow structure instead of the coaxial cable in the antenna to reduce the external conductor current and achieve a spherical ablation zone. We match between the antenna and the coaxial cable by an L-type matching network. The simulated results show that the roundness of the ablation zone of the hollow antenna is more than 85 % at 20 W and 600 s compared with the coaxial microwave ablation antenna. The hollow antenna operates at 2.45 GHz in the egg white, and the ablation experiment was carried out at the 20 W power for 600 s. The experimental results were in good agreement with the simulated results, which verified the ability of the antenna to generate a spherical ablation zone. The hollow antenna can effectively avoid damaging normal tissue and improve the accuracy and efficiency of microwave ablation.

Electromagnetic Navigation Bronchoscopy-Guided Microwave Ablation Combined With Uniportal Video-Assisted Thoracoscopic Surgery for Multiple Ground Glass Opacities

BackgroundAn increasing number of patients are being diagnosed with multiple ground glass opacities (GGOs), but a consensus on the treatment of these patients is still lacking. The aim of this study was to investigate the safety and feasibility of a novel technique, electromagnetic navigation bronchoscopy (ENB)-guided microwave ablation combined with uniportal video-assisted thoracoscopic surgery in patients with multiple GGOs. MethodsThe clinical, radiographic, surgical, and pathologic data of patients with multiple GGOs who underwent ENB-guided microwave ablation combined with uniportal video-assisted thoracoscopic surgery from October 2018 to December 2019 were reviewed. ResultsEleven patients with multiple GGOs underwent ENB-guided microwave ablation combined with uniportal video-assisted thoracoscopic surgery; they included 6 men and 5 women with a mean age of 61.3 ± 5.1 years (range, 53 to 68). Thirty-seven lesions were observed in the 11 patients, 21 of which were microwave ablated and 16 of which were surgically resected. Only 1 patient had postoperative pneumothorax and subcutaneous emphysema and was successfully discharged from the hospital after symptomatic treatment. The success rate and the efficiency of microwave ablation under ENB guidance were both 100%, with no other serious complications or procedure-related deaths occurring. No local metastasis or recurrence occurred in any patients during the follow-up period. ConclusionsElectromagnetic navigation bronchoscopy-guided microwave ablation combined with uniportal video-assisted thoracoscopic surgery is safe and feasible in patients with multiple GGOs suspected of having multiple primary lung cancers, and may represent an alternative approach for more patients, particularly patients who cannot tolerate the simultaneous resection of multiple tumors.

Clinical application of ultrasound-guided percutaneous microwave ablation for benign breast lesions: a prospective study

BackgroundBackground: Benign breast lesions are the most common diseases in adult women, which have been treated with minimally invasive therapies in recent years. Little is known about the feasibility of Microwave ablation (MWA) for benign breast lesion treatment. The primary aim of this prospective study was to evaluate the safety and efficiency of MWA as a potential therapeutic option for benign breast lesions in a single-center cohort study.MethodsWomen with possibly benign breast lesions based on an ultrasound (US) assessment who were scheduled to undergo MWA between November 2014 to July 2018 were included in the study. The patients underwent conventional US to measure the size of the lesion, Doppler US to assess the vascularity of the lesion, elastography to evaluate the stiffness of the mass, core needle biopsy of suspicious lesions, contrast-enhanced US to help determine the treatment plan and eventually MWA of the lesion. Lesions were followed at one, three, six, twelve and eighteen months after treatment to with the same imaging modalities.ResultsA total of 314 women aged 17 to 69 years old (mean = 36.9 ± 9.9 years) with 725 benign breast lesions (mean of maximum diameter = 10.86 ± 5.40 mm) were included. The frequency of palpable mass, pain and nipple discharge significantly decreased after treatment. Complete ablation rate was 97.8%, immediately after ablation, which increased to 100% after supplementary ablation of the 15 cases with incomplete ablation. Blood flow classification and lesion’s volume also showed a significant decrease, while both volume reduction ratio and disappearance rate significantly increased following treatment. The elasticity score of the lesions showed fluctuations across different follow-up intervals. None of the patients experienced major complications and the 1% who had mild symptoms were successfully treated.ConclusionMWA treatment is shown to be safe and efficient and has the potential to be considered as an alternative first line treatment for benign breast lesions.

Localized Chemotherapy Prevents Lung Metastasis After Incomplete Microwave Ablation of Hepatic VX2 Tumor.

Microwave ablation is emerging as an effective local treatment for solid tumors. The efficiency of microwave ablation in treating hepatocellular carcinoma is evidently limited by the incomplete ablation of large tumors and tumors in high-risk locations. Microwave ablation in conjunction with localized chemotherapy is a promising strategy for cancer therapy. In this study, we prepared As₂O₃-mPEG-PLGA-PLL nanoparticles by double emulsion method and investigated their efficacy to eliminate residual cancer cells and inhibit lung metastasis after microwave ablation of hepatic VX2 tumor. As₂O₃ formulations were administered into the residual tumor area for four times over four weeks after microwave ablation (As₂O₃ equivalent to 1 mg/kg body weight). Both As₂O₃ treatments showed good therapeutic effects, including inhibiting lung metastasis and decreasing the stiffness of the residual tumors. Additionally, As₂O₃-mPEG-PLGA-PLL nanoparticles had better anti-cancer efficacy than did the As₂O₃ treatment. Compared with As₂O₃ alone, As₂O₃-mPEG-PLGA-PLL nanoparticles could increase the expression of epithelial marker E-cadherin, decrease the expression of mesenchymal markers N-cadherin and snail, as well as down-regulate the expressions of PCNA (proliferation marker), CD34 (angiogenesis marker). The As₂O₃-mPEG-PLGA-PLL nanoparticles are an effective formulation for preventing lung metastasis through reversing EMT progress after incomplete ablation, thus it has the potential to be a new therapy strategy for HCC patients.

Safety and efficiency of ultrasound-guided low power microwave ablation in the treatment of cervical metastatic lymph node from papillary thyroid carcinoma: a mean of 32 months follow-up study.

To evaluate the safety and efficiency of microwave ablation (MWA) with low power of 20 w, respectively, in the treatment of cervical metastatic lymph node (CMLN) from papillary thyroid carcinoma (PTC) with a mean of 32-month follow-up. Eleven patients in total with 24 cervical lymph nodes (LNs) diagnosed with CMLN from PTC underwent MWA at a power of 20 w. We recorded images of the LNs under ultrasound first before MWA and 1, 3, 6, 12, months after MWA, and then every 6 months, respectively. The volumes of the LNs were compared before MWA and at each follow-up point after MWA. The thyroglobulin (Tg) test was performed before MWA and 3 months after MWA. All patients were successfully treated, and they showed no major complications. Before MWA, the mean volume of the LNs was 364.15 ± 306.89 mm3, which decreased to 234.10 ± 230.34 mm3, 107.51 ± 129.47 mm3, 20.88 ± 39.27 mm3, 3.38 ± 12.74 mm3, and completely disappeared at the follow-up point of 1, 3, 6, 12, and 18 months after MWA, respectively. The mean Tg was 11.81 ± 7.50 ng/ml, a data significantly decreased to 0.43 ± 0.11 ng/ml 3 months after MWA (P = 0.000). In the follow-up period, no recurrent lesions were found. For the treatment of CMLN from PTC, low power MWA showed good safety and efficacy. MWA is likely to be a candidate for patients with high risks or who refuse reoperation.

Percutaneous Microwave versus Radiofrequency Ablation of Colorectal Liver Metastases: Ablation with Clear Margins (A0) Provides the Best Local Tumor Control

PurposeTo identify and compare predictors of local tumor progression (LTP)-free survival (LTPFS) after radiofrequency (RF) ablation and microwave (MW) ablation of colorectal liver metastases (CLMs). Materials and MethodsThis is a retrospective review of CLMs ablated from November 2009 to April 2015 (110 patients). Margins were measured on contrast-enhanced computed tomography (CT) 6 weeks after ablation. Clinical and technical predictors of LTPFS were assessed using a competing risk model adjusted for clustering. ResultsTechnique effectiveness (complete ablation) was 93% (79/85) for RF ablation and 97% (58/60) for MW ablation (P = .47). The median follow-up period was significantly longer for RF ablation than for MW ablation (56 months vs. 29 months) (P < .001). There was no difference in the local tumor progression (LTP) rates between RF ablation and MW ablation (P = 0.84). Significant predictors of shorter LTPFS for RF ablation on univariate analysis were ablation margins 5 mm or smaller (P < .001) (hazard ratio [HR]: 14.6; 95% confidence interval [CI]: 5.2–40.9) and perivascular tumors (P = .021) (HR: 2.2; 95% CI: 1.1–4.3); both retained significance on multivariate analysis. Significant predictors of shorter LTPFS on univariate analysis for MW ablation were ablation margins 5 mm or smaller (P < .001) (subhazard ratio: 11.6; 95% CI: 3.1–42.7) and no history of prior liver resection (P < .013) (HR: 3.2; 95%: 1.3–7.8); both retained significance on multivariate analysis. There was no LTP for tumors ablated with margins over 10 mm (median LTPFS: not reached). Perivascular tumors were not predictive for MW ablation (P = .43). ConclusionsRegardless of the thermal ablation modality used, margins larger than 5 mm are critical for local tumor control, with no LTP noted for margins over 10 mm. Unlike RF ablation, the efficiency of MW ablation was not affected for perivascular tumors.

Maximizing efficiency of microwave ablation in normal hepatic parenchyma and hepatic colorectal metastases: Selection of the optimum microwave frequency

Maximizing efficiency of microwave ablation in normal hepatic parenchyma and hepatic colorectal metastases: Selection of the optimum microwave frequency