Radiofrequency Ablation System Research Articles

Novel self-expandable stent-based endobiliary radiofrequency ablation for unresectable malignant biliary obstruction

Endobiliary radiofrequency ablation (RFA) is an emerging endoscopic palliative adjunctive therapy used for the local treatment of unresectable malignant biliary obstruction (MBO). However, irregular ablation ranges caused by insufficient electrode-to-bile duct contact pose a significant obstacle. The aim was to investigate the feasibility of a self-expandable stent (SES)-based electrode with a customized RFA generator in the porcine liver and common bile duct (CBD). A SES-RFA system with polarity-switching was developed to perform endobiliary RFA. The ablation ranges of 20 ablation protocols were evaluated to validate the feasibility of the newly developed RFA system in the porcine liver. Nine of the 20 ablation protocols were selected for evaluation in the porcine CBD with cholangiography, endoscopy, and histological and immunohistochemical analysis. The SES-RFA system with polarity-switching was successfully constructed and demonstrated high accuracy and reproducibility. The ablation area was clearly identified between the two SESs. The ablation ranges and degree of mucosal damage including TUNEL- and HSP70-positive depositions increased proportionally with ablation protocols in the porcine liver and CBD (all P < .05). Ablation length and depth linearly increased with ablation protocols from 8.74 ± 0.25 to 31.25 ± 0.67 mm and 1.61 ± 0.09 to 11.94 ± 0.44 mm, respectively. The SES-RFA system with polarity-switching between electrodes provided an even circumferential area of ablation and enhanced ablation depth between the electrodes. This novel endobiliary RFA system is a promising modality for local ablation in patients with unresectable MBO.

Endoscopic radiofrequency ablation of pancreatic neuroendocrine tumors

Aim. To present the first experience of EUS-guided radiofrequency ablation in the treatment of patients with functioning neuroendocrine tumors of the pancreas. Materials and methods. Endoscopic radiofrequency ablation was performed in 2 patients with insulin-producing neuroendocrine tumor of the pancreatic head and clinical picture of organic hyperinsulinism. The radiofrequency ablation system includes a 19-gauge needle electrode to be conducted through the forceps aperture, a generator and an intraelectrode cooling system. Results. The efficacy of ultrasound-guided radiofrequency ablation in the cases presented above appears to be clinically proven. The outcomes include stabilization of the blood glucose level, a complete elimination of hypoglycemia-associated clinical symptoms. Both observations reveal no complications after the procedure. Conclusion. EUS-guided radiofrequency ablation appears to possess a potential for wider application as a minimally invasive intervention, thus introducing an alternative to surgical treatment of patients with neuroendocrine tumors of the pancreas. An experience of EUS-guided radiofrequency ablation is worth to be accumulated and outcomes of the method application to be analyzed on a larger number of clinical observations.

Thyroid Nodules: Emerging Trends in Detection and Visualization based on Citespace.

Thyroid nodule (TN) is a highly prevalent clinical endocrine disease. Many countries have formed guidelines on the prevention and treatment of TN based on extensive research. However, there is a scarcity of TN-related literature based on bibliometrics. This study aimed to evaluate the scientific achievements and progress of TN research from a global perspective by investigating the literature for 20 years through bibliometrics. We searched the literature on TN in the core collection of the Web of Science database from 2002 to 2021 and used the Citespace software to analyze the co-authorship, co-citation, and co-occurrence of countries, institutions, authors, keywords, and co-cited literature. We retrieved 12319 documents related to TN. The literature on TN has been growing since 2002. The United States has contributed the largest proportion of TN papers (20.64%), followed by China, Italy, and South Korea. The United States ranked first in terms of centrality (0.38). Haugen BR, Gharib H, and Cibas ES are the top three most cited authors. The papers published in Thyroid were cited most frequently (7952 times). The most prominent keywords were management, cancer, fine needle aspiration, diagnosis, malignant tumor, thyroid cancer, ultrasound, biopsy, benign, surgery, ablation, and cytology. All keywords could be divided into three categories: diagnosis stratification, treatment, and cancer. As far as potential hot spots are concerned, the keywords that have recently burst strongly and are still continuing are: "Association Guideline" (2018-2021), "Radiofrequency Ablation" (2017-2021), "Classification" (2019-2021), and "Data System" (2017-2021). Based on the current trends, the number of publications on TN will continue to increase. The United States is the most active contributor to research in this field. Previous literature focused on stratification, cancer, surgery, and ablation, and there were different opinions on the stratification of diagnosis. There were relatively few studies on pathogenesis and treatment using medicine. More focus will be placed on association guidelines, radiofrequency ablation, classification, and data system, which may be the next popular topics in TN research.

Bipolar radiofrequency ablation lesion areas and confluence: An exvivo study and technical report.

Radiofrequency ablation (RFA) has been used for nearly 100 years, treating an array of medical conditions including chronic pain. Radiofrequency (RF) energy depolarizes and repolarizes tissues adjacent to a probe producing heat and causing direct thermal injury. When positioned adjacent to neural structures, it leads to neural tissue injury and cell death interrupting pain signaling with the ultimate goal of providing lasting pain relief. Today, RFA is commonly used to treat cervical, thoracic, and lumbar zygapophyseal joints, sacroiliac joint, and more recently large peripheral joint-mediated pain. There are several applications of RFA systems, including bipolar, conventional thermal, cooled, protruding, and pulsed. As yet, no study has determined the best technical practice for bipolar RFA. This exvivo study examines RFA lesion midpoint (LMP) area and lesion confluence comparing three different commonly used gauge (g) probes (18-g, 20-g, and 22-g) with 10-mm active tips at various interprobe distances (IPD) to guide best technical practices for its clinical application. Bipolar RFA lesions were generated in preservative-free chicken breast specimens using three different gauge probes (18-g, 20-g, and 22-g) with 10-mm active tips at various IPD (6, 8, 10, 12, 14, 16, and 18 mm). RF was applied for 105 s (15-s ramp time) at 80°C for each lesion at both room and human physiological temperature. The specimen tissues were dissected through the lesion to obtain a length, width, and depth, which were used to calculate the LMP area (mm2 ). The LMP areas of each thermal ablation were investigated using visualization and descriptive analysis. The Kruskal-Wallis test was performed to compare LMP areas between the two temperature groups and the three different gauge probe subgroups at the various IPDs. Of the 36 RF lesions (14: 18-g, 12: 20-g, and 10: 22-g) performed, 24 demonstrated lesion confluence. The average time to reach 80°C was 16-17 s; therefore, the average time of RF-energy delivery (at goal temperature) was 88-89 s despite varying needle size or IPD. Comparing the 25 and 37°C groups, 18-g probes produced mean LMP areas of 73.7 and 79.2 mm2 , respectively; 20-g probes produced mean LMP areas of 66 and 66.8 mm2 , respectively; 22-g probes produced mean LMP areas of 56.6 and 59.7 mm2 , respectively. There was no statistical evidence to state a difference regarding LMP area between temperature groups; however, the 18-g probes produced consistently larger LMP areas in the 37°C compared to 25°C specimen groups at each IPD. Lesion confluence was lost for 18-g, 20-g, and 22-g probes at IPD of 14, 12, and 10 mm, respectively, in both 25 and 37°C groups. LMP area was similar between 6 and 8 mm IPD in all of the three-gauge groups; however, there was a significant drop in LMP area from 8 mm IPD to 10 mm and greater. The 18-g, 20-g, and 22-g probes all demonstrated a sharp decline in LMP area when increasing the IPD from 8 to 10 mm. This exvivo technical study evaluated bipolar RFA LMP areas and lesion confluence, and determined the recommended IPD of 18-g, 20-g, and 22-g probes to be less than 12, 10, and 8 mm, respectively, for best clinical practice. Placing bipolar probes at an IPD greater than 14, 12, and 10 mm, respectively, risks the loss of lesion confluence and failure to produce a clinically significant treatment response due to lack of nerve capture. In clinical practice, the use of injectate may produce larger lesions than demonstrated in this study. Additionally, invivo factors may impact ablation zone size and ablation patterns. As there are a paucity of studies comparing various RFA applications and conventional RFA needles are least expensive, it is possible that bipolar conventional RFA is more cost-effective than other techniques.

Case Reports of Low-Temperature Plasma Radiofrequency Treatment for Congenital Epiglottic Cysts in Neonates and Infants.

An uncommon benign condition in neonates, known as congenital epiglottic cyst, can lead to symptoms such as neonatal dyspnea, laryngeal stridor, and, in severe cases, even pose a potential threat of asphyxia-related mortality. A congenital epiglottic cyst is one of the neonatal emergencies. Fibrolaryngoscopy is the predominant method of diagnosis, and early identification, diagnosis, as well as treatment are the key points. Successful endoscopic ablation of congenital epiglottic cysts in 3 newborns was achieved through the utilization of a low-temperature plasma radiofrequency ablation system. Consequently, the purpose of this case report is to assist pediatric emergency physicians in the timely identification of congenital epiglottic cysts with the potential risk of mortality and to provide additional experience in clinical management.

Research on High Precision Temperature Acquisition System for Radiofrequency Ablation System

RFA (radiofrequency ablation) is a new type of tumor treatment in recent decades. It has excellent effects in treating certain tumors. Radiofrequency ablation technology is a physical-type treatment technology. At present, RF ablation technology has been very successful in medical clinics. Radiofrequency ablator, as a kind of medical device, implemented directly on the organs, which must ensure good stability and high safety. RF ablators can work in temperature control mode. In this mode, the accuracy of temperature sampling is critical. When working in temperature control mode, the ablator must monitor the temperature of the polar needle tip in real time. In this paper, we study the temperature sampling system for RF ablators, including hardware circuit design and filtering algorithm design.

Application of respiratory sensing technique in CT-guided radiofrequency ablation of liver malignancies.

This study aimed to examine the effectiveness and safety of respiratory sensing methods in nonvascular interventional therapy of liver tumors. In this study, 64 patients with primary liver cancer or liver metastasis were retrospectively analyzed. According to two widely used clinical techniques to limit respiratory movement-breath holding and respiratory sensing technology-they were randomly allocated into two groups: respiratory gated and respiratory training. We aimed to compare the application and effect of these two techniques in the nonvascular interventional therapy of liver tumors. The puncture times of the respiratory-gated and respiratory training groups were 5.34 ± 2.47 and 8.41 ± 3.63 min, respectively. Puncture errors were 10.00 ± 2.65 and 12.81 ± 8.57 mm, respectively. Puncture adjustment times were 3.06 ± 1.26 and 4.87 ± 1.69 times, respectively, and the differences were statistically significant (P < 0.01). Respiratory sensing technology has been effectively used to assist in puncturing liver malignant tumors using a radiofrequency (RF) ablation (RFA) system that is guided by computed tomography (CT) scans. It is superior to the classical breath-holding step puncture technique in terms of puncture time, puncture error, and puncture needle adjustment times.

Characterizing lesion morphology of a novel diamond-tip temperature-controlled irrigated radiofrequency ablation catheter.

The DiamondTemp ablation (DTA) system is a novel temperature-controlled irrigated radiofrequency (RF) ablation system that accurately measures tip-tissue temperatures for real-time power modulation. Lesion morphologies from longer RF durations with the DTA system have not been previously described. We sought to evaluate lesion characteristics of the DTA system when varying the application durations. A bench model using porcine myocardium was used to deliver discrete lesions in a simulated clinical environment. The DTA system was power-limited at 50 W with temperature set-points of 50 °C and 60 °C (denoted Group_50 and Group_60). Application durations were randomized with a range of 5-120 s. In total, 280 applications were performed. Steam pops were observed in five applications: two applications at 90 s and three applications at 120 s. Lesion size (depth and maximum width) increased significantly with longer applications, until 60 s for both Group_50 and Group_60 (depth: 4.5 ± 1.2 mm and 5.6 ± 1.3 mm; maximum width: 9.3 ± 2.7mm and 11.2 ± 1.7mm, respectively). As lesions transition from resistive to conductive heating (longer than 10 s), the maximum width progressed in a sub-surface propagation. Using a "Time after Temperature 60 °C" (TaT60) analysis, depths of 2-3 mm occur in 0-5 s and depths plateau at 4.6 ± 0.8 mm between 20 and 30 s. The DTA system rapidly creates wide lesions with lesion depth increasing over time with application durations up to 60 s. Using a TaT60 approach is a promising ablation guidance that would benefit from further investigation.

Radiofrequency ablation of the great saphenous vein; does the choice of monopolar or bipolar catheters affect outcomes?

Radiofrequency-based procedure is one of the leading methods of endovenous thermal ablation. The most fundamental difference with regards to currently available radiofrequency ablation systems is the way of electric current flow given to the vein wall; bipolar segmental and monopolar ablation. This study aimed to compare the monopolar ablation method with conventional bipolar segmental endovenous radiofrequency ablation method for the management of incompetent saphenous veins. Between November 2019 and November 2021, 121 patients with incompetent varicose veins who were treated either with the F-Care/monopolar (N = 49) or ClosureFast/bipolar (N = 72) were included in the study. A single extremity of each patient with isolated great saphenous vein insufficiency was enrolled. The differences between the two groups in demographic parameters, disease severity, treated veins, peri- and postoperative complications, and treatment efficacy indicators were retrospectively evaluated. There was no statistically significant difference between the groups regarding demographic parameters, disease severity, and treated veins in preoperative period (p > 0,05). The average procedural time was 21.4 ± 4minutes in the monopolar group, while it was 17.1 ± 3minutes in the bipolar group. In both groups, the venous clinical severity scores declined significantly compared with the preoperative period, however; there was no difference between groups (p > 0,05). The occlusion rate of the saphenofemoral junction and proximal saphenous vein after 1year was 94.1% in the bipolar group and 91.8% in the monopolar group (p = 0.4) while there was a significant difference in the occlusion rate of the shaft and distal part of the saphenous vein (93.2% in the bipolar group and 80.4% in the monopolar group, p = 0.04). Postoperative complications (bruising and skin pigmentation) were slightly higher in the bipolar group (p = 0.02, p = 0.01). Both systems are effective in treating the venous insufficiency of the lower extremity. Monopolar system revealed a better early postoperative course with similar occlusion rate of the proximal part of saphenous vein compared with bipolar system, however; the occlusion of the lower half of the saphenous vein was significantly lower which may negatively affect long-term occlusion rates and recurrence of the disease.

Durable patient-reported outcomes following 60-day percutaneous peripheral nerve stimulation (PNS) of the medial branch nerves

BackgroundChronic low back pain (CLBP) is often associated with clinical evidence of central nervous system sensitization and finding a clear source of nociceptive input can be challenging. Conventional therapies targeting peripheral spinal pain structures can fail to address centrally-mediated, underlying causes of pain. Sixty-day percutaneous peripheral nerve stimulation (PNS) applied to the lumbar medial branch nerves is a non-surgical, non-opioid treatment that may restore the balance of peripheral inputs to the central nervous system and reverse maladaptive changes in central pain processing. As a minimally invasive, non-destructive treatment, percutaneous PNS was designed to be used earlier in the treatment continuum than radiofrequency ablation or permanently-implanted neurostimulation systems. ObjectiveThe objective of this clinical trial was to characterize the durability of responses to medial branch PNS in a prospective multicenter case series study of CLBP patients recalcitrant to multiple non-surgical treatments. DesignProspective, multicenter clinical trial. PopulationAdults with CLBP without radicular leg pain who had previously failed multiple types of conventional treatments. InterventionSixty-day percutaneous PNS applied to the lumbar medial branch nerves. MethodsPercutaneous PNS leads were implanted under image guidance (ultrasound and/or fluoroscopy) and treatment was applied for up to 60 days, after which the leads were removed. Participants were followed through 14 months (12 months after the 2-month PNS treatment). Prospectively-defined endpoints included assessments of pain intensity, disability, pain interference, health-related quality of life, depression, and patient global impression of change. ResultsTreatment of CLBP with 60-day percutaneous PNS treatment produced clinically meaningful improvements in average pain intensity, disability, and/or pain interference for a majority of participants through the entire 14 month follow up period without requiring permanent system implantation. The proportion of participants experiencing clinically meaningful improvement in at least one outcome (pain intensiy, disability, pain interference) with PNS was 91% after 2 months, 79% at 5 months, 73% at 8 months, 75% at 11 months, and 77% at 14 months. There were no serious or unanticipated study-related adverse events. ConclusionThis prospective multicenter clinical trial demonstrates the clinical utility of percutaneous PNS when applied to the medial branch nerves for the treatment of chronic low back pain recalcitrant to non-surgical treatments. Given the minimally invasive nature of percutaneous PNS and the significant benefits experienced by participants, percutaneous PNS provides a safe and effective first-line neuromodulation treatment for patients with CLBP that may obviate the need for neuroablative procedures or permanent neurostimulation system implantation.

Bipolar Radiofrequency Ablation of the Adrenal Gland: In Vivo and Ex Vivo Experiments.

Laparoscopic adrenalectomy is currently the standard treatment modality for unilateral aldosterone-producing adenoma (APA); however, a less-invasive treatment is needed for its treatment. A new bipolar ablation system that poses a lower risk of complications has been recently developed. This study aimed to evaluate the safety and performance of a novel bipolar radiofrequency ablation (RFA) system for the treatment of APAs. Ablations were performed in an ex vivo study using bovine adrenal glands [group A: n = 6, single-probe; group B: n = 6, two probes, interprobe distance (ID) = 12 mm; group C: n = 6, two probes, ID = 20 mm]. The in vivo study was conducted in groups A and B (n = 2 each) using porcine adrenal glands. For the ex vivo study, the mean vertical diameter (Dv) of the coagulative necrosis area and the mean transverse diameter (Dt) values were 11.99 mm and 10.96 mm for group A, 12.66 mm and 10.0 mm for group B, and 23.37 mm and 22.10 mm for group C, respectively. For the in vivo study, the mean Dv and Dt values were 12.23 mm and 9.03 mm for group A, and 16.38 mm and 9.52 mm for group B, respectively. No heat-induced damage to the adjacent organs was observed. To our best knowledge, this is the first study to evaluate the performance of the bipolar system in RFA of the adrenal gland. RFA using the new bipolar ablation system is safe and produces a sufficient coagulation area to treat APAs.

An Investigation of Popping During Radiofrequency Ablation After Lenvatinib Administration for Hepatocellular Carcinoma.

Lenvatinib is available as a molecular target agent for hepatocellular carcinoma (HCC). In this study, we investigated the popping phenomena in patients with HCC who underwent radiofrequency ablation (RFA) after taking lenvatinib. Fifty-nine patients with HCC between 21-30 mm in diameter and no history of systemic treatment were enrolled in the study. The patients underwent RFA using a VIVA RFA SYSTEM with an ablation tip of 30 mm in length. For the initial lenvatinib administration, 16 patients had an adequate course of treatment and were treated with RFA as add-on therapy (combination group). The other 43 patients were treated by RFA monotherapy (monotherapy group). The popping frequency during RFA was recorded and compared. Popping frequency in the combination group (RFA combined with lenvatinib) was significantly higher than that in the monotherapy group. There was no significant difference between the combination group and the monotherapy group in ablation time, maximum output level, tumour temperature after ablation, or initial resistance value. Popping frequency was significantly higher in the combination group. It is possible that the intra-tumour temperature increased rapidly during RFA in the combination group due to the inhibitory effect of lenvatinib on tumour angiogenesis, leading to the occurrence of popping. Further studies are needed to investigate popping after RFA, and precise protocols need to be developed.

Stent-based electrode for radiofrequency ablation in the rat esophagus: a preliminary study

Endoluminal radiofrequency (RF) ablation has been widely used as a safe and effective treatment for Barrett’s esophagus. However, inadequate RF ablation may occur due to insufficient contact between the electrode and target tissues. Herein, a stent-based monopolar RF electrode (SE) was developed to evenly deliver RF energy to the inner wall of the rat esophagus. The optimal RF parameters were evaluated in the exposed rat esophagus. The temperature in the rat esophagus reached 70 ℃ in 89 s at 30 W, 59 s at 40 W, and 34 s at 50 W. The technical feasibility and efficacy of RF ablation using SE were evaluated based on changes in histological transformation and immunohistochemical parameters of tissues compared at immediately, 1 and 2 weeks after the procedure. The degrees of inflammatory cell infiltration, fibrotic changes, TUNEL, and HSP70 in the RF-ablated rat esophagus were significantly higher than compared with sham control (all p < 0.05). TUNEL-positive deposition gradually decreased, but HSP 70-positive deposition maintained a similar level for 2 weeks. The stent-based RF ablation was technically feasible and effective in evenly inducing thermal damages to the rat esophagus. The RF ablation system using the SE may represent a promising treatment for endoluminal malignancies.

First-in-man application of Liwen RF™ ablation system in the treatment of drug-resistant hypertrophic obstructive cardiomyopathy.

This study sought to evaluate the clinical applicability of the Liwen Liu RF™ ablation system for percutaneous intramyocardial septal radiofrequency ablation (PIMSRA). Data on new cardiac radiofrequency ablation devices for the treatment of hypertrophic obstructive cardiomyopathy (HOCM) are limited. From July 2019 to July 2020, a total of 68 patients with drug-resistant HOCM, who underwent PIMSRA with the Liwen RF™ ablation system, which has an ablation electrode of stepless adjustable length, were prospectively enrolled. Safety endpoints included, amongst others, the occurrence of pericardial effusion and/or hemorrhage, cardiac arrhythmias, device failure and procedural death. The reduction in left ventricular outflow tract (LVOT) gradients at 12 months follow-up were used as a surrogate marker for device efficacy. All procedures were technically successful. The total energy output time of the system was 75.8 (IQR: 30.0) min, and the average power was 43.61 ± 13.34 watts. No ablation system error occurred. The incidence of pericardial effusion or hemorrhage, transient arrhythmia and resuscitation was 8.8, 39.7, and 1.5% during procedure, respectively. None of the patients died. During 30-day follow-up, there were no complications with the exception of a pericardial effusion in one patient (1.5%). No further complications were reported after 30 days. The patients' resting [baseline: 75 (IQR: 48) vs. 12-months: 12 (IQR: 19) mmHg, p < 0.001] and provoked [baseline: 122 (IQR: 53) vs. 12-months: 41 (IQR: 59) mmHg, p < 0.001] LVOT gradients decreased significantly during follow-up. In this study, we demonstrate the safety and feasibility of the Liwen RF™ ablation system to treat HOCM. The system allows for significant and sustainable LVOT gradient reduction during 12-months of follow-up. Hence, the Liwen RF™ ablation system is a promising new device that has the potential to become an alternative to existing septal reduction concepts in HOCM patients.

Clinical Experience of Percutaneous Radiofrequency Ablation Using an arfa RF ABLATION SYSTEMⓇ in Various Organs.

To evaluate the feasibility, safety, and efficacy of radiofrequency (RF) ablation using an ablation system (arfa RF ABLATION SYSTEMⓇ; Japan Lifeline Co. Ltd.) for treating solid tumors in various organs. Between October 2019 and August 2021, 80 patients (29 women, 51 men; median age, 70.0 yr) underwent 107 RF ablation sessions using the ablation system to treat 151 tumors in the liver (n = 86), lung (n = 51), adrenal gland (n = 4), pleura (n = 4), bone (n = 3), lymph node (n = 2), and kidney (n = 1). The maximum tumor diameter was 2-40 mm (median, 11 mm). This study evaluated technical success (defined as the completion of planned RF ablation), technique efficacy (defined as the complete tumor ablation on follow-up images), and adverse events. Local tumor progression in 146 curatively treated malignant tumors was evaluated. The technical success rate was 100% (107/107). Ablation zones in two tumors were insufficient. Therefore, the primary technique efficacy rate was 98.1% (105/107). Grade 3 hepatic infarction (1.6%, 1/64) and grade 4 pleuritis (3.4%, 1/29) occurred respectively after liver and lung RF ablation. During the median follow-up period of 10.2 months (Interquartile range, 4.2 and 16.4 months), local tumor progression developed in two tumors (1.4%, 2/146). The arfa RF ABLATION SYSTEMⓇ is a feasible, safe, and effective RF ablation device for managing solid tumors in various organs.

In vivo thermal ablation control using three-dimensional echo decorrelation imaging in swine liver

In experiments modeling clinical thermal ablation of liver tumors, radiofrequency ablation (RFA) of swine liver was controlled using a three-dimensional (3D) ultrasound echo decorrelation imaging. Up to six ablations with target diameter 2 cm were done in each animal’s liver using a clinical RFA system (RITA/Angiodynamics, 50 W, 6–10 min). Paired sequential volumes of beamformed pulse-echo data (inter-frame time &amp;lt;50 ms) were acquired from a Siemens Acuson SC2000 scanner with a Z6Ms transesophageal matrix array and transferred via an Ethernet to a computer running a custom MATLAB program to compute 3D echo decorrelation images. When the average cumulative, motion-compensated echo decorrelation within the planned ablation zone exceeded a prespecified threshold determined from preliminary trials, ablation was ceased automatically. After each procedure, the animal’s liver was excised, uniformly sectioned, and optically scanned to reconstruct 3D ablation zones. Local ablation prediction was assessed using receiver operating characteristic (ROC) curve analysis comparing echo decorrelation images to co-registered ablation zones. To assess differences in outcomes, ablation zone volumes, ablation rates, Dice coefficients for measured versus targeted ablation zones, and ROC curves were statistically compared for controlled versus uncontrolled trials. The results indicate promise for control of in vivo thermal ablation using motion-corrected 3D echo decorrelation imaging.

Efficacy and Safety of Radiofrequency Ablation Versus Surgery for Thyroid Nodules

Objectives: To assess the efficacy and safety of radiofrequency (RF) ablation versus surgery for benign thyroid nodules for 24 months period. Methods: From January 2019 to January 2021, 200 patients with nodular goiters who underwent surgery (group A) and 183 patients treated by radiofrequency ablation (group B) were enrolled in this study. Inclusion criteria were the following: 1) cosmetic problem, 2) nodule-related symptoms, 3) refusal of surgery (for group B). An internally cooled radiofrequency ablation system and an 18 g internally cooled electrode were used. We compared the 2 groups in terms of efficacy, and safety during a 2-year follow-up. Results: Nodule type did not differ between groups, although in total 60.1 % were solid, 31.3 % were mixed, and 8.6 % were cystic. However, the number of nodules, median volume before surgery, and diameter of the nodule differed significantly. The median volume reduction was 34.6 % at 1 month, 56.1 % at 3 months, 70.6 % at 6 months, 73.9 % at 12 months, and 74.9 % at 24 months. Any volume reduction between follow-up intervals was statistically significant (p &lt; 0.000). The most patients had no complications. However, surgical patients were more likely to have complications such as bleeding, hoarseness, and infection (14.5 %) than the RFA group (1.6 %). Conclusion: Surgical resection and radiofrequency ablation are both effective treatments of nodular goiter. Compared with surgery, the advantages of radiofrequency ablation include fewer complications, preservation of thyroid function, and fewer hospitalization days. Therefore, radiofrequency ablation should be considered a first-line treatment for benign thyroid nodules.

Multipolar radiofrequency ablation via three bipolar electrodes with C-arm type X-ray fluoroscopy assistance for hepatocellular carcinoma: An observational study

The present study aimed to investigate the therapeutic efficacy and safety of the insertion technique of 3 bipolar electrodes in patients with hepatocellular carcinoma (HCC), using C-arm type X-ray fluoroscopy-assisted ultrasonography (US) in guiding a multipolar radiofrequency ablation (RFA) system. Seventy-three patients with HCC treated with a multipolar RFA system (1 electrode, n = 2; 2 electrodes, n = 56; 3 electrodes, n = 17) were enrolled in this retrospective cohort study. To analyze their therapeutic outcome in this study, we divided among 17 patients using 3 electrodes into 2 subgroups: the C-arm type X-ray fluoroscopy-assisted (n = 7) and the US-guided alone groups (n = 10). Therapeutic efficacy and safety were analyzed between the 2 groups. Multipolar RFA treatment was performed safely in all cases, and no severe adverse events occurred. Comparing the patient background of the group treated using 1 or 2 electrodes with that treated using 3 electrodes, larger-sized HCC was treated using 3 electrodes (P < .001). The differences in overall and recurrence-free survival rates between the 1- or 2-electrode and the 3-electrode groups were not significantly different (P = .843 and P = .891). Comparing the C-arm type X-ray fluoroscopy-assisted and the US-guided alone groups among patients treated using 3 electrodes, technical factors such as total ablation time and the number of sessions were not significantly different between the 2 groups. The local tumor progression rate was not significantly different between the 2 groups (P = .942). Multipolar RFA treatment was effective for the treating HCC; using 3 electrodes was suitable for larger-sized HCCs. The technical approach with C-arm type X-ray fluoroscopy assistance using 3 electrodes was useful for operators to perform safe and appropriate insertion techniques by synchronizing the US and X-ray fluoroscopy images.

Radiofrequency Ablation of Recurrent Metastatic Papillary Thyroid Cancer to a Lymph Node

Radiofrequency Ablation of Recurrent Metastatic Papillary Thyroid Cancer to a Lymph Node

Ex-vivo investigation of radiofrequency ablation in pancreatic adenocarcinoma after neoadjuvant chemotherapy.

ObjectiveEndoscopic ultrasound (US)‐guided radiofrequency ablation (RFA) has been investigated for pancreatic ductal adenocarcinoma (PDAC) but studies are limited and heterogeneous. Computed tomography (CT) scan features may predict RFA response after chemotherapy but their role is unexplored. The primary aim was to investigate the efficacy of ex‐vivo application of a dedicated RFA system at three power on surgically resected PDAC in patients who underwent neoadjuvant chemotherapy. The secondary aim was to explore the association between pre‐treatment CT‐based quantitative features and RFA response.MethodsFifteen ex‐vivo PDAC samples were treated by RFA under US control at three power groups (10, 30, and 50 W). Short axis necrosis diameter was measured by two expert blinded pathologists as the primary outcome. Two radiologists independently reviewed preoperative CT images.ResultsEighty percent of specimens showed coagulative necrosis consisting of few millimeters: 5.7 ± 3.9 mm at 10 W, 3.7 ± 2.2 mm at 30 W, and 3.5 ± 2.4 mm at 50 W (p = 0.3), without a significant correlation between power setting and mean necrosis short axis (rho = –0.28; p = 0.30). Good agreement was seen between pathologists (k = 0.76; 95% confidence interval 0.55–0.98). Logistic regression analysis did not show associations between CT features and RFA response.ConclusionsRFA causes histologically evident damage with coagulative necrosis of a few millimeters in 80% of ex‐vivo PDAC samples after chemotherapy and no clinical or pre‐operative CT features can predict efficacy. Power settings do not correlate with the histological ablation area. These results are of relevance when employing RFA in vivo and planning clinical trials on its role in PDAC patients.