• Journal of the Korean Society of Radiology
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• v.85 no.3
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• pp.618-630
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• 2024

Purpose To compare the efficacy and safety of radiofrequency ablation (RFA) and ethanol ablation (EA) followed by RFA in treating mixed cystic and solid thyroid nodules. Materials and Methods We included 243 nodules from 243 patients who underwent RFA for mixed cystic and solid benign nodules. The nodules were divided into two groups (RFA alone and EA + RFA). We evaluated volume reduction rate (VRR), therapeutic success rate, improvement in symptomatic and cosmetic issues, complications, and adverse effects. Results The RFA group included 204 patients, and the EA + RFA group included 39 patients. The long-term success rates in the RFA only and EA + RFA groups were 90.2% and 97.4%, respectively. The mean VRR at the last follow-up in the RFA and EA + RFA groups were 81.6% and 87.2%, respectively. Therapeutic results were similar in both groups at the last followup. Cosmetic and symptomatic problems markedly improved in both groups. No major complications were observed. Conclusion Both RFA alone and EA + RA are safe and effective methods for treating mixed cystic and solid thyroid nodules, although EA + RFA is slightly more effective.

• Korean Journal of Radiology
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• v.19 no.6
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• pp.1099-1109
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• 2018

Objective: In a proof of concept study, we compared no-touch radiofrequency ablation (NtRFA) in bipolar mode with conventional direct tumor puncture (DTP) in terms of local tumor control (LTC), peritoneal seeding, and tumorigenic factors, in the rabbit VX2 subcapsular hepatic tumor model. Materials and Methods: Sixty-two rabbits with VX2 subcapsular hepatic tumors were divided into three groups according to the procedure: DTP-RFA (n = 25); NtRFA (n = 25); and control (n = 12). Each of the three groups was subdivided into two sets for pathologic analysis (n = 24) or computed tomography (CT) follow-up for 6 weeks after RFA (n = 38). Ultrasonography-guided DTP-RFA and NtRFA were performed nine days after tumor implantation. LTC was defined by either achievement of complete tumor necrosis on histopathology or absence of local tumor progression on follow-up CT and autopsy. Development of peritoneal seeding was also compared among the groups. Serum hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF) and interleukin-6 (IL-6) were measured via ELISA (Elabscience Biotechnology Co.) after RFA for tumorigenic factor evaluation. Results: Regarding LTC, there was a trend in NtRFA (80%, 20/25) toward better ablation than in DTP-RFA (56%, 14/25) (p = 0.069). Complete tumor necrosis was achieved in 54.5% of DTP-RFA (6/11) and 90.9% of NtRFA (10/11). Peritoneal seeding was significantly more common in DTP-RFA (71.4%, 10/14) than in NtRFA (21.4%, 3/14) (p = 0.021) or control (0%). Elevations of HGF, VEGF or IL-6 were not detected in any group. Conclusion: No-touch radiofrequency ablation led to lower rates of peritoneal seeding and showed a tendency toward better LTC than DTP-RFA.

• Journal of the Korean Society of Radiology
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• v.81 no.3
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• pp.620-631
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• 2020

Purpose We aimed to assess local tumor progression (LTP) rate and associated prognostic factors in 92 patients who underwent radiofrequency ablation (RFA) using saline-perfused electrodes to treat hepatocellular carcinoma (HCC) (≤ 5 cm). Materials and Methods Total 92 patients with 148 HCCs were treated with RFA using saline-perfused electrodes, from 2009 to 2015. We retrospectively evaluated technical success, technique efficacy, and LTP rates. Potential prognostic factors for LTP were perivascular tumor, subphrenic tumor, artificial ascites, tumor size (≥ 2 cm), and previous treatment of transarterial chemoembolization. Analysis was performed by lesion, rather than by person. Results During follow-up period from 1 to 97.4 months, total cumulative LTP rates were 7.9%, 11.4%, and 14.6% at 1, 3, and 5 years, respectively. These values were significantly higher in the perivascular (35.1%; p = 0.009) and subphrenic group (38.9%; p = 0.002) at 5-year. We did not observe any significant difference in LTP according to other prognostic factors (p > 0.05). Conclusion RFA with saline-perfused electrode is a safe and effective treatment modality for HCC (≤ 5 cm), with lower LTP rates. Nevertheless, perivascular and subphrenic HCCs demonstrated higher LTP rate than other sites. It is imperative to note that perivascular and subphrenic location of HCC are associated with a high risk of local recurrence, despite the use of saline-perfused electrodes.

• Korean Journal of Radiology
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• v.25 no.3
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• pp.289-300
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• 2024

Objective: To prospectively evaluate the outcomes of ultrasound (US)-guided radiofrequency ablation (RFA) in tertiary hyperparathyroidism (THPT). Materials and Methods: Patients with THPT underwent RFA between September 2017 and January 2022. Laboratory parameters, including serum intact parathyroid hormone (iPTH) levels, were monitored for 48 months after RFA and compared with the levels at baseline. Complications related to RFA and changes in hyperparathyroidism-related clinical symptoms were recorded before and after RFA. Results: A total of 42 patients with THPT were recruited for this study. Ultimately, 36 patients with renal failure and 2 patients who underwent successful renal transplantation (male:female, 17:21; median age, 54.5 years) were enrolled. The follow-up time was 21.5 ± 19.0 months in the 36 patients with renal failure. In these 36 patients, iPTH levels were significantly decreased to 261.1 pg/mL at 48 months compared with the baseline value of 1284.9 pg/mL (P = 0.012). Persistent hyperparathyroidism, defined as iPTH levels maintained at > 585.0 pg/mL for 6 months after treatment, occurred in 4.0% of patients (1/25). Recurrent hyperparathyroidism, defined as iPTH levels > 585.0 pg/mL after 6 months, were 4.0% (1/25) and 0.0% (0/9) at 6 months and 4 years after treatment, respectively. In two patients with THPT after successful renal transplantation, iPTH decreased from the baseline value of 242.5 and 115.9 pg/mL to 171.0 and 62.0 pg/mL at 6 months after treatment. All complications resolved within 6 months of ablation without medical intervention, except in 10.5% (4/38) patients with permanent hypocalcemia. The overall symptom recovery rate was 58.8% (10/17). The severity scores for bone pain, arthralgia, and itchy skin associated with hyperparathyroidism improved after treatment (P < 0.05). Conclusion: US-guided RFA is an effective and safe alternative to surgery in the treatment of patients with TPTH and improves hyperparathyroidism-related clinical symptoms.

• Korean Journal of Radiology
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• v.24 no.8
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• pp.761-771
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• 2023

Objective: To investigate the association among the electrode placement method, electrode type, and local tumor progression (LTP) following percutaneous radiofrequency ablation (RFA) for small hepatocellular carcinomas (HCCs) and to assess the risk factors for LTP. Materials and Methods: In this retrospective study, we enrolled 211 patients, including 150 males and 61 females, who had undergone ultrasound-guided RFA for a single HCC < 3 cm. Patients were divided into four combination groups of the electrode type and placement method: 1) tumor-puncturing with an internally cooled tip (ICT), 2) tumor-puncturing with an internally cooled wet tip (ICWT), 3) no-touch with ICT, and 4) no-touch with ICWT. Univariable and multivariable Cox proportional-hazards regression analyses were performed to evaluate the risk factors for LTP. The major RFA-related complications were assessed. Results: Overall, 83, 34, 80, and 14 patients were included in the ICT, ICWT, no-touch with ICT, and no-touch with ICWT groups, respectively. The cumulative LTP rates differed significantly among the four groups. Compared to tumor puncturing with ICT, tumor puncturing with ICWT was associated with a lower LTP risk (adjusted hazard ratio [aHR] = 0.11, 95% confidence interval [CI] = 0-0.88, P = 0.034). However, the cumulative LTP rate did not differ significantly between tumor-puncturing with ICT and no-touch RFA with ICT (aHR = 0.34, 95% CI = 0.03-1.62, P = 0.188) or ICWT (aHR = 0.28, 95% CI = 0-2.28, P = 0.294). An insufficient ablative margin was a risk factor for LTP (aHR = 6.13, 95% CI = 1.41-22.49, P = 0.019). The major complication rates were 1.2%, 0%, 2.5%, and 21.4% in the ICT, ICWT, no-touch with ICT, and no-touch with ICWT groups, respectively. Conclusion: ICWT was associated with a lower LTP rate compared to ICT when performing tumor-puncturing RFA. An insufficient ablation margin was a risk factor for LTP.

• Journal of Biomedical Engineering Research
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• v.28 no.2
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• pp.235-243
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• 2007

Hepatocellular carcinoma is significant worldwide public health problem with an estimated annually mortality of 1,000,000 people. Radiofrequency (RF) ablation is an interventional technique that in recent years has come to be used for treatment of the hepatocellualr carcinoma, by destructing tumor tissues in high temperatures. Numerous studies have been attempted to prove excellence of RF ablation and to improve its efficiency by various methods. However, the attempts are sometimes paradox to advantages of a minimum invasive characteristic and an operative simplicity in RF ablation. The aim of the current study is, therefore, to suggest an improved RF ablation technique by identifying an optimum RF pattern, which is one of important factors capable of controlling the extent of high temperature region in lossless of the advantages of RF ablation. Three-dimensional finite element (FE) model was developed and validated comparing with the results reported by literature. Four representative Rf patterns (sine, square, exponential, and simulated RF waves), which were corresponding to currents fed during simulated RF ablation, were investigated. Following parameters for each RF pattern were analyzed to identify which is the most optimum in eliminating effectively tumor tissues. 1) maximum temperature, 2) a degree of alteration of maximum temperature in a constant time range (30-40 second), 3) a domain of temperature over $47^{\circ}C$ isothermal temperature (IT), and 4) a domain inducing over 63% cell damage. Here, heat transfer characteristics within the tissues were determined by Bioheat Governing Equation. Developed FE model showed 90-95% accuracy approximately in prediction of maximum temperature and domain of interests achieved during RF ablation. Maximum temperatures for sine, square, exponential, and simulated RF waves were $69.0^{\circ}C,\;66.9^{\circ}C,\;65.4^{\circ}C,\;and\;51.8^{\circ}C$, respectively. While the maximum temperatures were decreased in the constant time range, average time intervals for sine, square, exponential, and simulated RE waves were $0.49{\pm}0.14,\;1.00{\pm}0.00,\;1.65{\pm}0.02,\;and\;1.66{\pm}0.02$ seconds, respectively. Average magnitudes of the decreased maximum temperatures in the time range were $0.45{\pm}0.15^{\circ}C$ for sine wave, $1.93{\pm}0.02^{\circ}C$ for square wave, $2.94{\pm}0.05^{\circ}C$ for exponential wave, and $1.53{\pm}0.06^{\circ}C$ for simulated RF wave. Volumes of temperature domain over $47^{\circ}C$ IT for sine, square, exponential, and simulated RF waves were 1480mm3, 1440mm3, 1380mm3, and 395mm3, respectively. Volumes inducing over 63% cell damage for sine, square, exponential, and simulated RF waves were 114mm3, 62mm3, 17mm3, and 0mm3, respectively. These results support that applying sine wave during RF ablation may be generally the most optimum in destructing effectively tumor tissues, compared with other RF patterns.

• The Korean Journal of Pain
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• v.35 no.4
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• pp.447-457
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• 2022

Background: Ultrasound-guided genicular nerve radiofrequency (RF) procedures are of interest in the management of chronic knee pain. A wide variety of demographic, clinical, and procedural characteristics can affect treatment success. This study aimed to determine predictive factors to provide superior treatment outcomes. Methods: The demographic, clinical, and technical data of patients who received genicular nerve RF for knee pain between September 2016 and September 2021 were evaluated. A positive outcome was defined as at least 50% pain relief on a pain score for at least 6 months. Logistic regression analysis was performed to determine the factors associated with a successful response to genicular RF. Results: Among 206 patients who underwent genicular RF, 62% of the patients reported successful outcomes at 6 months. In the multivariate model, targeting 5 nerves (odds ratio [OR], 6.184; 95% confidence interval [CI], 2.291-16.690; P < 0.001) was the most significant predictor of successful outcomes. Multivariable logistic regression analysis showed that prognostic genicular nerve block with a 50% cut-off value (OR, 2.109; 95% CI, 1.038-4.287; P = 0.039), no opioid use (OR, 2.753; 95% CI, 1.405-5.393; P = 0.003), and depression (OR, 0.297; 95% CI, 0.124-0.713; P = 0.007) were the predictive factors significantly associated with response to genicular RF. Conclusions: Clinical and technical factors associated with better treatment outcomes were ultimately targeting more nerves, performing prognostic block, no opioid use, and no depression. These results are expected to be considered when selecting patients for genicular RF.

• Journal of Chest Surgery
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• v.43 no.6
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• pp.635-641
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• 2010

Background: Radiofrequency endovenous ablation of incompetent saphenous vein has gaining popularity over the conventional ligation and stripping as a minimally invasive technique. The latest version of radiofrequency endovenous catheter, $VNUS^{\circledR}Colosure$ fast VNUS medical Technologies, San Jose, CA, adopted a segmental ablation system, instead of continous pullback, is designed to reduce treatment time in comparison with the previous model $VNUS^{\circledR}Colosure$ plus VNUS medical Technologies, San Jose, CA. The purpose of this study is to compare the difference between two endovenous radiofrequency ablation systems in terms of treatment efficacy and complication rates. We analyze the initial efficacy and complication rates of $VNUS^{\circledR}Colosure$ fast with $VNUS^{\circledR}Colosure$ plus. Material and Method: Between June 2006 and August 2009, $VNUS^{\circledR}Colosure$ plus was performed to treat varicose vein on 59 limbs in 41. patients and $VNUS^{\circledR}Colosure$ fast was performed on 76 limbs in 67 patients. We retrospectively compared in both group with sex, mean treatment time, mean treatment diameter, conjugated treatment, and complications after the procedure. Result: All patient were symptomatic and diagnosed as varicose vein and underwent level 2 clinical classification with color duplex scan. The mean treatment time for the great saphenous vein was significantly less with $VNUS^{\circledR}Colosure$ fast ($17.0{\pm}6.5min$) than $VNUS^{\circledR}Colosure$ plus ($62.7{\pm}9.8min$). There was no significant difference in 1 yr closure rate between groups (p=0.32). Minor complications such as skin burn, thrombophlebitis, ecchymosis, hematoma, cellulitis, tenderness, and there were not different between the groups. Conclusion: Both $VNUS^{\circledR}Colosure$ fast and $VNUS^{\circledR}Colosure$ plus are effective methods of endovenous saphenous ablation. $VNUS^{\circledR}Colosure$ fast is superior to the previous model with less treatment time preserving compatible efficacy and complications. The efficacy of $VNUS^{\circledR}Colosure$ fast for long term closure rate remains to be established.

• Tuberculosis and Respiratory Diseases
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• v.72 no.2
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• pp.228-231
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• 2012

Bronchobiliary fistula (BBF), defined as an abnormal communication between the biliary duct and bronchial trees, is a very rare condition. Bilioptysis is a pathognomonic finding for BBF. We studied a 58-year-old man, who had a BBF complicated by liver biloma that occurred after radiofrequency ablation. The diagnosis was confirmed by the presence of bile-stained sputum and an Endoscopic Retrograde Cholangio-Pancreatography. BBF was treated successfully by endoscopic sphincterotomy and biliary drainage with insertion of a double pig-tail plastic stent into the biloma. We suggest that the optimal choice of treatment modality for BBF depends on the natural course of the underlying disease, and the status of the biliary stricture.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.9
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• pp.4349-4352
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• 2016

Purpose: To evaluate whether combined transarterial chemoembolization (TACE) with radiofrequency ablation (RFA) or percutaneous ethanol injection (PEI) for hepatocellular carcinoma (HCC) have superior efficacy to transarterial chemoembolization (TACE) alone a retrospective review was conducted. Methods: During January 2009 to March 2013, 108 patients with hepatocellular carcinoma underwent TACE or combined therapies (TACE+RFA or TACE+PEI). The long-term survival rates were evaluated in those patients by various statistical analyses. Results: The cumulative survival rates in the combined TACE+RFA/PEI group were significantly superior to those in the TACE alone group. When the comparison among the groups was restricted to patients with two or three tumors fulfilling the Milan criteria, significantly greater prolongation of survival was observed in the combined TACE+ RFA/PEI group than in the RFA/PEI alone group. Conclusions: In terms of the effect on the survival period, combined TACE+ RFA/PEI therapy was more effective than TACE monotherapy, and also more effective than PEI or RFA monotherapy in cases with multiple tumors.