Thyroid nodule rupture after radiofrequency ablation: case report and literature review.

Purpose: Radiofrequency ablation (RFA) is an effective and safe modality for the treatment of thyroid nodules. Nodule rupture is a major complication of RFA. There is little known on the natural history of nodule rupture due to a lack of clinical experience and no consensus on its management. A comprehensive review of nodule rupture presentation, diagnosis, and management is needed. Methods: We report a case of nodule rupture and conduct a literature review. A total of 33 patients experiencing nodule rupture after RFA were included, and their clinical presentation, management, and outcomes were collected and analyzed. Results: Nodule rupture presents with acute swelling (90.3%) and pain (77.4%) within 7 months of RFA procedure, most commonly due to disruption of the anterior thyroid capsule (87%), and can be diagnosed with ultrasonography. Most ruptures can be managed conservatively, exemplified by our reported case. There are no reported cases of long-term sequalae. Conclusion: Nodule rupture is the second most common major complication of RFA. Based on the available evidence, we propose a treatment algorithm for nodule rupture and recommendations for future data collection to address gaps in our understanding of rupture etiology and effective management.

Radiofrequency ablation for papillary thyroid microcarcinoma close to the thyroid capsule versus far from the thyroid capsule: a retrospective study.

INTRODUCTION: The aim of this study was to evaluate the safety and efficacy of ultrasound-guided radiofrequency ablation (RFA) for the management of papillary thyroid microcarcinoma (PTMC) close to the thyroid capsule. MATERIAL AND METHODS: This was a retrospective study of 202 patients with PTMC who underwent RFA close to the thyroid capsule and 80 patients with PTMC who underwent RFA far from the thyroid capsule between June 2015 and December 2022. The follow-up time after RFA, change in size of tumour, location, thyroid function, the rates of PTMC disappearance, and complications were evaluated. RESULTS: A total of 202 patients with PTMC close to the thyroid capsule and 80 patients with PTMC far from the thyroid capsule successfully treated with RFA were studied. The thyroid function including free triiodothyronine (fT3), free thyroxine (fT4), triiodothyronine (T3), thyroxine (T4), and thyroid-stimulating hormone (TSH) showed no changes after RFA for one months in both groups. The tumour size was increased at 1, 3, and 6 months after RFA compared with pre-operative RFA in both groups. The tumour size was decreased at 12 and 24 months after RFA compared with pre-operative RFA both in both group. Seventy-nine PTMC close to the thyroid capsule and 30 PTMC far from the thyroid capsule completely disappeared as assessed by ultrasound examination. Eighty-four PTMC patients close to the thyroid capsule and 34 PTMC patients far from the thyroid capsule had minor complications after RFA treatment. The complication rates between the 2 groups were similar. CONCLUSION: Ultrasound-guided RFA seems to be an effective and safe method for patients with PTMC close to the thyroid capsule.

Can Machine Learning Predict Favorable Outcome After Radiofrequency Ablation of Hepatocellular Carcinoma?

PURPOSE: The standard practice for limited-stage hepatocellular carcinoma (HCC) is the resection or the use of local ablative techniques, such as radiofrequency ablation (RFA). The outcome after RFA depends on a complex interaction between the patient's general condition, hepatic function, and disease stage. In this study, we aimed to explore using a machine learning model to predict the response. PATIENTS AND METHODS: A retrospective study was conducted for patients with RFA for a localized HCC between 2018 and 2022. The collected clinical, radiologic, and laboratory data were explored using Python and XGBoost. They were split into a training set (70%) and a validation set (30%). The primary end point of this study was to predict the probability of achieving favorable outcomes 12 months after RFA. Favorable outcomes were defined as the patient was alive and HCC was controlled. RESULTS: One hundred and eleven patients were eligible for the study. Males were 78 (70.3%) with a median age of 57 (range of 43-81) years. Favorable outcome was seen in 62 (55.9%) of the patients. The 1-year survival rate and control rate were 94.6%, and 61.3%, respectively. The final model harbored an accuracy and an AUC of 90.6% and 0.95, respectively, for the training set, while they were 78.9% and 0.80, respectively, for the validation set. CONCLUSION: Machine learning can be a predictive tool for the outcome after RFA in patients with HCC. Further validation by a larger study is necessary.

Radiofrequency ablation of hepatocellular carcinoma guided by real-time physics-based ablation simulation: a prospective study.

OBJECTIVES: To assess the safety and efficacy of radiofrequency ablation (RFA) guidance software that incorporated patient-specific physics-based simulation of each ablation volume. MATERIALS AND METHODS: Patients referred for curative ablation of hepatocellular carcinoma (HCC) of 2-5 cm diameter were prospectively enrolled. RFA was performed under general anesthesia. Procedure planning and intraprocedural modifications were guided by computer simulation of each ablation. The segmented target (tumor with 5 mm margin) was registered to and superimposed on subsequent 3D multiplanar images. The applied RF energy was used to calculate a simulated ablation volume which was displayed relative to the electrode and segmented target, to depict any untreated target tissue. After each additional ablation, the software updated the accumulated simulated ablation volume in relation to the target. The primary endpoints were technical efficacy and rate of local tumor progression (LTP). RESULTS: Sixty-eight tumors were ablated during 57 procedures in 52 patients (68.3 ± 9.2 years old, 78.8% male); 15 (26.3%) had multiple lesions and 23 (39.1%) had prior HCC treatment. The mean tumor diameter was 2.73 (±0.64) cm. The intraprocedural simulation directed additional overlapping ablations in 75.9% of tumors. Technical success and efficacy were 100% at 3-month contrast enhanced CT or MRI follow-up after the single treatment session. Cumulative incidence function estimates for 1- and 2-year LTP were 3.9% and 20.2%, respectively. CONCLUSION: This prospective study found computer-assisted guidance that simulated each ablation was both safe and efficacious. The low rate of LTP was similar to studies that employed stereotactic guidance and ablation confirmation, without requiring a second contrast enhanced study.

Cryoballoon pulmonary vein isolation versus radiofrequency ablation of the pulmonary veins and left atrial posterior wall: Patient-reported outcomes.

BACKGROUND: Data are lacking on patient-reported outcomes (PRO) following cryoballoon ablation (CBA) versus radiofrequency ablation (RFA). We sought to evaluate QoL and clinical outcomes of cryoballoon pulmonary vein isolation only (CRYO-PVI-ONLY) versus RFA with PVI and posterior wall isolation (RF-PVI+PWI) in a large prospective PRO registry. METHODS: Patients who underwent AF ablation (2013-2016) at our institution were enrolled in an automated, prospectively maintained PRO registry. CRYO-PVI-ONLY patients were matched (1:1) with RF-PVI+PWI patients based on age, gender, and type of AF (paroxysmal vs. persistent). QoL and clinical outcomes were assessed using PRO surveys at baseline and at 1-year. The atrial fibrillation symptom severity scale (AFSSS) was the measure for QoL. Additionally, we assessed patient-reported clinical improvement, arrhythmia recurrence, and AF burden (as indicated by AF frequency and duration scores). RESULTS: A total of 296 patients were included (148 in each group, 72% paroxysmal). By PRO, a significant improvement in QoL was observed in the overall study population and was comparable between CRYO-PVI-ONLY and RF-PVI+PWI (baseline median AFSSS of 11.5 and 11; reduced to 2 and 4 at 1 year, respectively; p = 0.44). Similarly, the proportion of patients who reported improvement in their overall QoL and AF related symptoms was high and similar between the study groups [92% (CRYO-PVI-ONLY) vs. 92.8% (RF-PVI+PWI); p = 0.88]. Arrhythmia recurrence was significantly more common in the CRYO-PVI-ONLY group (39.7%) compared to RF-PVI+PWI (27.7 %); p = 0.03. Comparable results were observed in paroxysmal and persistent AF. CONCLUSION: CRYO-PVI-ONLY and RF-PVI+PWI resulted in comparable improvements in patient reported outcomes including QoL and AF burden; with RF-PVI+PWI being more effective at reducing recurrences.

Novel and Advanced Ultrasound Techniques for Thyroid Thermal Ablation.

Thyroid radiofrequency ablation and microwave ablation are widely adopted minimally invasive treatments for diverse thyroid conditions worldwide. Fundamental skills such as the trans-isthmic approach and the moving shot technique are crucial for performing thyroid ablation, and advanced techniques, including hydrodissection and vascular ablation, improve safety and efficacy and reduce complications. Given the learning curve associated with ultrasound-guided therapeutic procedures, operators need training and experience. While training models exist, limited attention has been given to ultrasound maneuvers in ablation needle manipulation. This article introduces two essential maneuvers, the zigzag moving technique and the alienate maneuver, while also reviewing the latest ultrasound techniques in thyroid ablation, contributing valuable insights into this evolving field.

Radiofrequency ablation for solitary T1N0M0 papillary thyroid carcinoma in the danger triangle area: a preliminary analysis.

OBJECTIVES: To evaluate the feasibility, efficacy, and safety of radiofrequency ablation (RFA) for solitary T1N0M0 papillary thyroid carcinoma (PTC) in the danger triangle area. METHODS: 94 participants (mean age 44.45 ± 13.08; 73 females) with solitary T1N0M0 PTC in the danger triangle area who underwent percutaneous RFA at the hospital from January 2018 to April 2020 were retrospectively analyzed. Key ablation procedures included sufficient paratracheal fluid isolation, low-power, and short active tip (5 mm working electrode). Tumor size changes at different time points after RFA, technical success rates, tumor disappearance, disease progression, and complications were recorded and compared. RESULTS: Contrast-enhanced ultrasonography revealed that complete tumor ablation was performed with a 100% success rate in these patients. Post-ablation, the maximum diameter and volume of the ablation zone increased at the first and third month (p < 0.001), followed by a gradual decrease in size, without significant difference by the 6th month. The tumor disappearance rate was 76.59% (72/94), with higher rates in the T1a group compared to the T1b group (80% [64/80] VS57.1% [8/14], p < 0.001). There were no local recurrences. The incidence of new lesions and LNM was 3.2% (3/94), limited to the T1a subgroup. Further ablation was successfully applied to all new lesions and LMN. Mild voice changes were the only complication, with a rate of 3.2% (3/94), resolved within 4 months after RFA. CONCLUSIONS: Sufficient paratracheal fluid isolation combined with a low-power, short active tip radiofrequency ablation strategy is a safe and effective method for treating solitary T1N0M0 PTC in the danger triangle area.

The 'danger triangle' area comprises the dorsal edge of the thyroid gland, the lateral tracheal wall, and the anterior edge of the esophageal wall. When PTC tumors are present within the danger triangle, there is only limited space available for ablation. Furthermore, the proximity of the tumor with the esophagus, trachea, and thyroid capsule can complicate technical treatment success, potentially increasing the chance of local tumor recurrence and nerve injury. Therefore, the most effective approach for managing PTC lesions within the danger triangle remains undetermined. The goal of this study was to clarify the viability of ultrasound-guided RFA as a means of managing solitary T1N0M0 PTC tumors within the danger triangle area, providing a foundation for future clinical decision-making efforts.

Comparative Efficacy and Safety of Radiofrequency Ablation and Microwave Ablation in the Treatment of Benign Thyroid Nodules: A Systematic Review and Meta-Analysis.

OBJECTIVE: The current body of evidence lacks clarity regarding the comparative efficacy and safety of radiofrequency ablation (RFA) and microwave ablation (MWA) as minimally invasive treatments for benign thyroid nodules. The primary objective of this study is to clarify these concerns. MATERIALS AND METHODS: A comprehensive search was conducted using the Cochrane Library, Scopus, Europe PMC, and Medline databases until October 10th, 2023, using a combination of relevant keywords. This study incorporated literature that compared RFA and MWA for benign thyroid nodules. The primary outcome was the volume reduction ratio (VRR) from baseline to follow-up. Secondary outcomes were symptom score, cosmetic score, ablation time, major complications rate, hemorrhage, hoarseness, skin burn, cough, and sympathetic nerve injury. We used Risk of Bias in Non-randomized Studies - of Interventions (ROBINS-I) tool to assess the risk of bias in the included studies. We employed random effects models to analyze the standardized mean difference (SMD) and odds ratio for the presentation of outcomes. RESULTS: Nine studies with 2707 nodules were included. The results of our meta-analysis indicated similar efficacy between RFA and MWA in terms of VRR during the 1 (SMD 0.06; 95% confidence interval [CI]: -0.13 to 0.26; P = 0.52) and 3 (SMD 0.11; 95% CI: -0.03 to 0.25; P = 0.12) months of follow-up. VRR was significantly higher in RFA than in MWA at the 6 (SMD 0.25; 95% CI: 0.06-0.43; P = 0.008) and 12 month of follow-up (SMD 0.38; 95% CI: 0.17 to 0.59; P < 0.001). There were no significant differences between RFA and MWA in symptom scores, cosmetic scores, or the incidence of complications, including hemorrhage, hoarseness, skin burn, cough, and sympathetic nerve injury. CONCLUSION: RFA showed a higher VRR than MWA at 6 and 12-month follow-ups, with a comparable safety profile.

Comparison of the efficacy and safety of ultrasound-guided radiofrequency ablation and microwave ablation for the treatment of unifocal papillary thyroid microcarcinoma: a retrospective study.

PURPOSE: This study aimed to compare the efficacy and safety of ultrasound-guided RFA and MWA in the treatment of unifocal PTMC. METHODS: This retrospective study included 512 patients with 512 unifocal papillary thyroid microcarcinomas (PTMCs) who underwent RFA (n = 346) and MWA (n = 166) between January 2021 and December 2021. The volumes of the ablation areas were measured during follow-up, and the volume reduction rates were evaluated. The ablation duration, volume of hydrodissection, and ablation-related complications were also compared between the groups. RESULTS: All lesions received complete ablation and no local or distant recurrences were observed in the two groups. A larger volume of isolation liquid was used for RFA than for MWA (p = 0.000). Hoarseness occurred in seven patients who underwent RFA (p = 0.102). At the 1-week follow-up, the mean volume of the areas ablated by RFA was smaller than that of the areas ablated by MWA (p = 0.049). During follow-ups at months 3, 9, 12, 15, and 18, the mean volumes of the ablated areas were larger in the RFA group than in the MWA group (all, p < 0.05). The mean volume of the ablated lesions increased slightly at the 1-week follow-up and then decreased at 1 month after ablation in both groups. The absorption curve of the ablated lesions in the RFA group was similar to that in the MWA group. CONCLUSIONS: RFA and MWA are both efficient and safe methods for treating unifocal PTMC. They may be alternative techniques for patients who are not eligible or are unwilling to undergo surgery.

Radiofrequency ablation for papillary thyroid microcarcinoma with a trachea-adjacent versus trachea-distant location.

OBJECTIVE: To evaluate the outcomes of radiofrequency ablation (RFA) for papillary thyroid microcarcinoma (PTMC) adjacent to the trachea and compare them with those of PTMC distant from the trachea. METHODS: Patients who received RFA for solitary low-risk PTMC between June 2014 and July 2020 were reviewed and classified into adjacent and distant groups. To balance between-group confounders, the propensity score matching approach was employed. Volume, volume reduction ratio (VRR), tumor disappearance, complications, and disease progression were assessed and compared between the groups. Furthermore, factors affecting disease progression were evaluated. RESULTS: A total of 122 and 470 patients were included in the adjacent and distant groups, respectively. Overall VRR was 99.5% ± 3.1 and cumulative tumor disappearance rate was 99.4% after a mean follow-up time of 40.1 months ± 16.2. Overall disease progression and complications incidence were 3.7% and 1.0%, respectively. No substantial differences were observed between the two groups in the latest volume (0.8 mm3 ± 4.1 vs. 0.9 mm3 ± 4.2, p = .77), VRR (99.7% ± 1.6 vs. 99.5% ± 2.7, p = .75), cumulative tumor disappearance rate (92.6% vs. 94.2%, p = .58), and incidence of disease progression (4.1% vs. 4.5%, p = .70) and complication (1.7% vs. 0.8%, p = .86) after 1:2 matching. Additionally, tracheal adjacency exhibited no association with disease progression in multivariate Cox regression analysis (p = .73). CONCLUSION: For eligible patients with PTMC located adjacent to or distant from the trachea, RFA may offer a safe and effective alternative treatment method.

Comparison of the Therapeutic Efficacy and Technical Outcomes between Conventional Fixed Electrodes and Adjustable Electrodes in the Radiofrequency Ablation of Benign Thyroid Nodules.

OBJECTIVE: This study aimed to compare therapeutic efficacy and technical outcomes between adjustable electrode (AE) and conventional fixed electrode (FE) for radiofrequency ablation (RFA) of benign thyroid nodules. MATERIALS AND METHODS: Between 2013 and 2021, RFA was performed on histologically proven benign thyroid nodules. For the AE method, AE length ≥ 1 cm with higher power and < 1 cm with lower power were utilized for ablating feeding vessels and nodules, especially those near anatomical structures, respectively. The therapeutic efficacy (volume reduction rate [VRR], complication rate, and regrowth rate) and technical outcomes (total energy delivery, ablated volume/energy, RFA time, and ablated volume/time) of FE and AE were compared. Continuous parameters were compared using a two-sample t-test or Mann-Whitney U test, and categorical parameters were compared using a chi-squared test or Fisher's exact test. RESULTS: A total of 182 nodules (FE: 92 vs. AE: 90) in 173 patients (mean age ± standard deviation, 47.0 ± 14.7 years; female, 90.8% [157/173]; median follow-up, 726 days [interquartile range, 441-1075 days]) were analyzed. The therapeutic efficacy was comparable, whereas technical outcomes were more favorable for AE. Both electrodes demonstrated comparable overall median VRR (FE: 92.4% vs. AE: 84.9%, P = 0.240) without immediate major complications. Overall regrowth rates were comparable between the two groups (FE: 2.2% [2/90] vs. AE: 1.1% [1/90], P > 0.99). AE demonstrated a shorter median RFA time (FE: 811 vs. AE: 627 seconds, P = 0.009). Both delivered comparable median energy (FE: 42.8 vs. AE: 29.2 kJ, P = 0.069), but AE demonstrated higher median ablated volume/energy and median ablated volume/time (FE: 0.2 vs. AE: 0.3 cc/kJ, P < 0.001; and FE: 0.7 vs. AE: 1.0 cc/min, P < 0.001, respectively). CONCLUSION: Therapeutic efficacy between FE and AE was comparable. AE demonstrated better technical outcomes than FE in terms of RFA time, ablated volume/energy, and ablated volume/time.

Cutaneous fistula formation after thyroid nodule rupture: A rare complication after radiofrequency ablation.

BACKGROUND: With innovative treatment options such as radiofrequency ablation (RFA) for thyroid nodules, new complications are being identified. It is important to define and delineate complications in order to counsel patients appropriately about treatment options and their associated risks and benefits. METHODS: A 46-year-old male presented with a left thyroid nodule (6.5 cm). Fine needle aspiration results were benign. He started to develop intermittent dyspnea and underwent one RFA procedure. Approximately 6 days post-RFA, the neck area was raised and red with blister. The skin overlying the blister underwent eventual dehiscence with fluid spillage. Several months later, MRI imaging showed substernal extension with tracheal deviation. RESULTS: A left thyroid lobectomy was performed with cutaneous excision and successful closure of a fistula. CONCLUSIONS: This is the first reported case of a thyroid nodule rupture following RFA which manifested into a thyro-cutaneous fistula and required surgical intervention.

Comparison of laparoscopic radiofrequency ablation with percutaneous radiofrequency ablation in the treatment of chronic hepatitis B-related hepatocellular carcinoma involving specific sites: A retrospective cohort study.

BACKGROUND: This study compared the effectiveness and safety of laparoscopic radiofrequency ablation (LRFA) and percutaneous radiofrequency ablation (PRFA) in the treatment of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) involving specific sites. METHODS: This retrospective cohort study included patients with HBV-related HCC involving specific sites treated with LRFA or PRFA between January 2012 and December 2020. The overall survival (OS), disease-free survival (DFS), and complications were compared between the LRFA and PRFA groups. The Cox proportional-hazards regression model was used to determine the factors affecting prognosis. RESULTS: This study included 109 patients: 69 in the LRFA group and 40 cases in the PRFA group. No significant differences were found in the 3-year OS rate between the two groups (73.7% vs. 70.0%, P = 0.514), but the LRFA group showed a higher 3-year DFS rate than the PRFA group (58.2% vs. 42.5%, P = 0.018). The RFA method was not associated with OS but was independently associated with DFS (LRPA vs. PRFA, HR = 2.078, P = 0.012). The common complications were ascites, pleural effusion, and fever in the two groups. The occurrence of complications in patients treated with LRFA or PRFA was similar (15.9% vs. 12.5%, P = 0.785). CONCLUSION: LRFA was associated with a better DFS in patients with HBV-related HCC involving specific sites. Thus, LRFA might have more advantages in treating liver cancer involving specific sites.

Sonographic Evolution and Pathologic Findings of Papillary Thyroid Cancer After Radiofrequency Ablation: A Five-Year Retrospective Cohort Study.

Background: The criteria for determining technical efficacy of thermal ablation for papillary thyroid carcinoma (PTC) are not clearly defined. We analyzed the involution process of the ablation zone with clear pathologic results on core-needle biopsy (CNB) to clarify the relationship between sonographic changes and pathologic findings. Methods: This retrospective cohort study included 382 patients with unifocal T1N0M0 PTC who underwent radiofrequency ablation (RFA) between May 2014 and August 2021. Patients with a single ablation zone biopsy (recommended at 3 or 6 months for T1a and 6 or 12 months for T1b) and regular neck ultrasound (US)/contrast-enhanced ultrasound imaging follow-up at 1, 3, 6, and 12 months and every 6-12 months thereafter after RFA were included. Patients also underwent yearly chest computed tomography. CNB was performed in the target lesion ablation zone's central, peripheral, and surrounding thyroid parenchyma to detect the presence of tumor cells. If the thyrotropin (TSH) was >2 mU/L, levothyroxine was prescribed with the intention of keeping the TSH 0.5-2 mU/L. Technical efficacy was defined as tumor disappearance by imaging follow-up together with the pathologically confirmed absence of tumor cells in the ablation zone. Results: During the mean follow-up period of 67.8 ± 18.2 months (22-110 months), the overall incidence of persistent disease and the technical efficacy rate were 3.9% (15/382; 2.9% of T1a, and 12.2% of T1b) and 96.1%, respectively. Tumor size (p = 0.03) and subcapsular location (p = 0.04) were risk factors associated with persistent disease. The technical success rate was 100%. Of the 367 ablation zones with benign CNB results, 336 (91.6%) showed tumor disappearance on US and no re-emergence of imaging-visible tumors during follow-up. Male sex (p = 0.006), age <40 years (p = 0.003), T1a tumor (p < 0.01), and energy per milliliter (p < 0.03) were significantly associated with tumor disappearance. Conclusions: US-guided RFA is an effective treatment for small low-risk PTC. Tumor disappearance on US after RFA may suggest an excellent prognosis and confirm complete ablation of the macroscopic tumor, but this sonographic finding is generally late and requires histological confirmation.

Long-Term Outcomes and Risk Factors of Radiofrequency Ablation for T1N0M0 Papillary Thyroid Carcinoma.

Importance: Radiofrequency ablation (RFA) has gained increasing interest as a minimally invasive procedure to treat low-risk papillary thyroid carcinoma (PTC). Considering the indolent nature of this disease, studies in large populations with long follow-up would be invaluable to further substantiate the effectiveness of RFA. Objective: To evaluate the long-term (58.5 months) outcomes of patients with T1N0M0 PTC who underwent RFA and investigate risk factors for local tumor progression (LTP). Design, Setting, and Participants: This cohort study included 1613 patients aged 18 years or older with T1N0M0 PTC who underwent ultrasonography-guided RFA between January 2014 and December 2020 at the Chinese People's Liberation Army General Hospital in Beijing, China. Included in the analysis were patients with PTC (confirmed by biopsy) with a maximum diameter of 20 mm or less; no evidence of extrathyroidal extension (capsular disruption or involvement of perithyroidal tissue), lymph node metastasis, or distant metastasis on ultrasonography or computed tomography; and no evidence of an aggressive subtype of PTC on biopsy. Patients with PTC larger than 2 cm, less than 12 months of follow-up, or inadequate follow-up information were excluded. Data were analyzed in April 2023. Main Outcomes and Measures: Long-term progression rate, disease-free survival, and complete tumor disappearance and their associations with patient and tumor characteristics. Disease-free survival was calculated using Kaplan-Meier analysis. Cox proportional hazards regression analyses were performed to assess risk factors for LTP and complete tumor disappearance. Results: The study comprised 1613 patients (mean [SD] age, 43.3 [10.2] years; 1256 women [77.9%]) with 1834 T1N0M0 PTC tumors. During a mean follow-up of 58.5 months (range, 27 to 111 months), LTP was observed in 69 patients (4.3%), including 42 (2.6%) with tumor recurrence and 27 (1.7%) with tumor persistence. Cumulative disease-free survival rates at 1, 3, 5, and 8 years were 98.0%, 96.7%, 96.0%, and 95.7%, respectively. The overall complication rate was 2.0% (32 patients), with 6 (0.4%) major complications. Independent risk factors for LTP included subcapsular tumor location 2 mm or less from the capsule or trachea (hazard ratio [HR], 3.36; 95% CI, 2.02-5.59; P < .001) and multifocal tumors (HR, 2.27; 95% CI, 1.30-3.96; P = .004). Furthermore, 1376 patients (85.3%) showed complete tumor disappearance at follow-up ultrasonographic examination. Factors associated with complete tumor disappearance included age 40 years or less (HR, 0.78; 95% CI, 0.70-0.87; P < .001), stage T1a tumors (HR, 0.37; 95% CI, 0.31-0.45; P < .001), and unifocal tumors (HR, 0.50; 95% CI, 0.42-0.60; P < .001). Conclusions and Relevance: In this cohort study, ultrasonography-guided RFA for T1N0M0 PTC had excellent long-term outcomes. Patients with unifocal T1N0M0 PTC and subcapsular tumor location more than 2 mm from the capsule or trachea may be the best candidates for RFA.

Volume reduction rate of radiofrequency ablation in ≤ 2 cm Bethesda IV thyroid nodules.

OBJECTIVE: This prospective observational study aimed to evaluate the efficacy of radiofrequency ablation (RFA) in treating ≤ 2 cm thyroid nodules with Bethesda IV cytology and C-TIRADS 4A categorization. Additionally, the factors influencing the completed absorption of ablation (CAA) were examined. METHODS: A total of 62 cases with 62 nodules underwent ultrasound-guided RFA and were included in the study. The volume reduction rate (VRR), CAA, and incomplete absorption of ablation (IAA) were assessed at the 1st, 3rd, 6th, and subsequent 6-month follow-ups. Clinical and ultrasound features were compared between the CAA and IAA groups at the 12th month follow-up. RESULTS: The average VRR at the 1st, 3rd, 6th, 12th month, and last follow-up were -88.6%, 16.0%, 59.7%, 82.0%, and 98.2%, respectively. More than half of the nodules achieved a 90% VRR after 1 year of RFA, with 88.7% demonstrating CAA at the end of the study (follow-up duration of 14 to 63 months). Nodules with grade 3 vascularity and those associated with chronic thyroiditis showed delayed CAA at the 12th month follow-up (p = 0.036 and 0.003, respectively). CONCLUSION: RFA is an effective technique for treating ≤ 2 cm thyroid nodules with Bethesda IV cytology and C-TIRADS 4A categorization. Nodules with grade 3 blood supply and patients with chronic thyroiditis exhibited an impact on the completed absorption following RFA. CLINICAL RELEVANCE STATEMENT: Our study has shown that radiofrequency ablation is an effective treatment for ≤ 2 cm thyroid nodules classified as Bethesda IV cytology. However, we identified that high vascularity of the nodule and chronic thyroiditis are adverse factors affecting the completed absorption of the ablation. KEY POINTS: •Radiofrequency ablation (RFA) is an effective technique for treatment of ≤ 2 cm Bethesda IV category thyroid nodules. •Higher blood supply and chronic thyroiditis influence the completed absorption after RFA.

3D fusion is superior to 2D point-to-point contrast-enhanced US to evaluate the ablative margin after RFA for hepatocellular carcinoma.

PURPOSE: To compare the efficiency of three-dimensional (3D) and two-dimensional (2D) contrast-enhanced ultrasound (CEUS)-derived techniques in evaluating the ablative margin (AM) after radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC). METHODS: In total, 98 patients with 98 HCCs were enrolled. The 2D CEUS point-to-point imaging (2D CEUS-PI) was conducted by comparing the pre- and post-RFA 2D CEUS images manually, and the 3D CEUS fusion imaging (3D CEUS-FI) was conducted by fusing the pre- and post-RFA 3D CEUS images automatically. These two techniques were compared in distinguishing an adequate AM ≥ 5 mm. Risk factors for local tumor progression (LTP) after RFA were analyzed by the Kaplan-Meier method with log-rank test. RESULTS: The mean registration time of 3D CEUS-FI and 2D CEUS-PI was 5.0 and 9.3 min, respectively (p < 0.0001). The kappa coefficient was 0.680 for agreement between 2D CEUS-PI and 3D CEUS-FI in the evaluation of AM (p < 0.0001). Tumors with AM < 5 mm by 2D CEUS-PI were all identified as AM < 5 mm by 3D CEUS-FI. Nonetheless, 16 (26%) tumors identified as AM ≥ 5 mm by 2D CEUS-PI were re-classified as AM < 5 mm by 3D CEUS-FI. During a median follow-up time of 31.2 months (range, 3.2-66.0 months), LTP was identified in 8 tumors. The estimated 1-/2-/3-year cumulative incidence of LTP was 4.4%, 8.1%, and 10.3%, respectively. Higher estimated cumulative incidence of LTP was identified in tumors with AM < 5 mm by 2D CEUS-PI (at 3-year, 27.2% vs 0%; p < 0.001), and by 3D CEUS-FI (at 3-year, 20.7% vs 0%; p = 0.004). CONCLUSION: 3D CEUS-FI excelled in the evaluation of AM when compared with 2D CEUS-PI. With equivalent efficacy in the prediction of LTP, 3D CEUS-FI was superior to 2D CEUS-PI for its automatic and time-saving procedure. CLINICAL RELEVANCE STATEMENT: 3D CEUS fusion imaging may serve as an effective tool in evaluating ablative margin and predicting local tumor progression after RFA in HCC. KEY POINTS: • Both 2D and 3D CEUS-derived techniques could evaluate ablative margin (AM) after RFA for hepatocellular carcinoma. • 3D CEUS fusion imaging was more precise in the evaluation of AM compared to 2D CEUS point-to-point imaging, with advantages of its automatic and time-saving procedure. • An inadequate AM < 5 mm evaluated by CEUS-derived techniques was the only risk factor of LTP after RFA for hepatocellular carcinoma (p < 0.001 for 2D CEUS point-to-point imaging, and p = 0.004 for 3D CEUS fusion imaging).

Follow-up strategy of radiofrequency ablation for papillary thyroid microcarcinoma: defining a response-to-ablation system.

OBJECTIVE: To define a response-to-ablation system based on dynamic risk stratification proposed by the 2015 American Thyroid Association guidelines for predicting clinical outcomes and guiding follow-up strategies for patients with low-risk papillary thyroid microcarcinoma (PTMC) who underwent radiofrequency ablation (RFA). METHODS: This retrospective study reviewed patients with low-risk PTMC who underwent RFA between 2014 and 2018. We classified patients into three groups based on their response to therapy at the 1-year follow-up: complete, indeterminate, and incomplete. The primary endpoints were local tumor progression (LTP) and disease-free survival (DFS). RESULTS: Among the 748 patients (mean age, 43.7 years ± 9.8; 586 women), 4.0% (30/748) had LTP during a median follow-up of 5 years. The response was complete in 80.2% (600/748) of the patients, indeterminate in 18.1% (135/748), and incomplete in 1.7% (13/748). The LTP rate in the final follow-up was 1% (6/600), 8.1% (11/135), and 100% (13/13), respectively. The risk of LTP was significantly different in the incomplete response group (HR, 1825.82; 95% CI: 458.27, 7274.36; p < 0.001) and indeterminate response group (HR, 8.12; 95% CI: 2.99, 22.09; p < 0.001) than in the complete response group. There were significant differences in DFS among groups (p < 0.001). The proportion of variation explained and C-index of the system was high (27.66% and 0.79, respectively). CONCLUSIONS: We defined a response-to-ablation system that provides a new paradigm for the management of patients with PTMC who underwent RFA. Our data confirm that the system can effectively predict the risk of LTP and guide ongoing follow-up recommendations. KEY POINTS: • The response-to-ablation system can classify patients with low-risk PTMC who underwent RFA into complete, indeterminate, or incomplete response categories. • Results suggest that, in this population, this system can identify three separate cohorts of patients who have significantly different clinical outcomes. • The response-to-ablation system will help better tailor the ongoing follow-up recommendations.

LI-RADS category is associated with treatment outcomes of small single HCC: surgical resection vs. radiofrequency ablation.

OBJECTIVES: To assess whether the Liver Imaging Reporting and Data System (LI-RADS) category is associated with the treatment outcomes of small single hepatocellular carcinoma (HCC) after surgical resection (SR) and radiofrequency ablation (RFA). METHODS: This retrospective study included 357 patients who underwent SR (n = 209) or RFA (n = 148) for a single HCC of ≤ 3 cm between 2014 and 2016. LI-RADS categories were assigned. Overall survival (OS), recurrence-free survival (RFS), and local tumor progression (LTP) rates after treatment were compared according to the LI-RADS category (LR-4/5 vs. LR-M) before and after propensity score matching (PSM). Prognostic factors for treatment outcomes were assessed. RESULTS: In total, 357 patients (mean age, 59 years; men, 272) with 357 HCCs (294 LR-4/5 and 63 LR-M) were included. After PSM (n = 78 in each treatment group), there were 10 and 11 LR-M HCCs in the SR and RFA group, respectively. There were no significant differences in OS or RFS. However, SR provided a lower 5-year LTP rate than RFA (1.4% vs. 14.9%, p = 0.001). SR provided a lower 5-year LTP rate than RFA for LR-M HCCs (0% vs. 34.4%, p = 0.062) and LR-4/5 HCCs (1.5% vs. 12.0%, p = 0.008). The LI-RADS category was the sole risk factor associated with poor OS (hazard ratio [HR] 3.79, p = 0.004), RFS (HR 2.12; p = 0.001), and LTP (HR 2.89; p = 0.032). CONCLUSION: LI-RADS classification is associated with the treatment outcome of HCC, supporting favorable outcomes of SR over RFA for LTP, especially for HCCs categorized as LR-M. CLINICAL RELEVANCE STATEMENT: Liver Imaging Reporting and Data System category has a potential prognostic role, supporting favorable outcomes of surgical resection over radiofrequency ablation for local tumor progression, especially for hepatocellular carcinoma categorized as LR-M. KEY POINTS: • SR provided a lower 5-year LTP rate than RFA for HCCs categorized as LR-M (0% vs. 34.4%, p = 0.062) and HCCs categorized as LR-4/5 (1.5% vs. 12.0%, p = 0.008). • There is a steeply increased risk of LTP within 1 year after RFA for LR-M HCCs, compared to SR. • The LI-RADS category was the sole risk factor associated with poor OS (HR 3.79, p = 0.004), RFS (HR 2.12; p = 0.001), and LTP (HR 2.89; p = 0.032) in patients with HCC of ≤ 3 cm treated with SR or RFA.

Temperature-Mediated Neural Interventions in Knee Osteoarthritis: a Review of Cryoneurolysis and Cooled Radiofrequency Ablation with Ultrasound Guidance.

PURPOSE OF REVIEW: Knee osteoarthritis is a debilitating chronic disease affecting nearly half of the world's population at some point in their lives. Treatment of pain and loss of function associated with this disease has been limited. In this review, we seek to explore how neural interventions with ultrasound guidance may be an emerging option for non-pharmacologic pain relief in patients with knee osteoarthritis. RECENT FINDINGS: Cryoneurolysis techniques have been demonstrated to provide pain relief out to 150 days post-treatment in knee osteoarthritis in select individuals. There have also been studies of cryoneurolysis pre-operatively to total knee replacement providing reduced pain, reduced opioid use post-operatively, and shorter hospital length of stay. Cooled radiofrequency ablation (CRFA) has been demonstrated to significantly reduce pain, improve functionality, and reduce pharmacologic needs in knee osteoarthritis out to 2 years. Both interventions appear to have increased accuracy with ultrasound, and CRFA appears to be associated with improved patient outcomes. The research demonstrates the efficacy of both cryoneurolysis and cooled radiofrequency ablation in the treatment of knee osteoarthritis. Ultrasound guidance in neurolysis provides an additional tool with real-time, high-accuracy nerve localization. These therapies should be considered for certain patients to assist in pain management in the non-operative and post-operative phase of knee osteoarthritis management. Further research is needed to further define the long-term effects and the long-term utility of the techniques in knee pain.