Moving-Shot versus Fixed Electrode Techniques for Radiofrequency Ablation: Comparison in an Ex-Vivo Bovine Liver Tissue Model

하은주,백정환,이정현 대한영상의학회 2014 Korean Journal of Radiology Vol.15 No.6

Objective: To compare the ablation characteristics of the moving-shot technique (MST) and the fixed electrode technique (FET) for radiofrequency (RF) ablation in an ex-vivo bovine liver tissue model. Materials and Methods: We performed RF ablation using FET in 110 bovine liver blocks using 11 different ablation times ranging from 5 seconds to 5 minutes (10 blocks per each time duration). Ten bovine liver blocks at each ablation time of 1- or 2-minute, were ablated with MST, which treated conceptual ablation units by moving the electrode tip. We evaluated the ablation volume obtained with FET across ablation time lengths. The results of FET and MST performed with the same ablation time lengths, i.e., 1- and 2-minute ablation time were also compared. Results: The ablation volume achieved with FET gradually increased with increasing ablation time; however, the pair-wise statistical comparison between 2 neighboring ablation time lengths was not significant after 30 seconds. MST with either 1- or 2-minute ablation time achieved larger ablation volumes (1.1 ± 0.2 mL vs. 2.7 ± 0.3 mL, p < 0.001; and 1.4 ± 0.2 mL vs. 5.6 ± 0.4 mL, p < 0.001, respectively), longer true RF times (46.7 ± 4.6 seconds vs. 60 seconds, p < 0.001; and 64.8 ± 4.6 seconds vs. 120 seconds, p < 0.001, respectively), fewer numbers of RF cut-offs (1.6 ± 0.5 vs. 0, p < 0.001; and 5.5 ± 0.5 vs. 0, p < 0.001, respectively), and greater energy deposition (2050.16 ± 209.2 J vs. 2677.76 ± 83.68 J, p < 0.001; and 2970.64 ± 376.56 J vs. 5564.72 ± 5439.2 J, p < 0.001, respectively), than FET. Conclusion: The MST can achieve a larger ablation volume by preventing RF cut-off, compared with the FET in an ex-vivo bovine liver model.

Active contour configuration model for estimating the posterior ablative margin in image fusion of real-time ultrasound and 3D ultrasound or magnetic resonance images for radiofrequency ablation: an experimental study

이중교,이민우,최동일 대한초음파의학회 2018 ULTRASONOGRAPHY Vol.37 No.4

Purpose: The purpose of this study was to evaluate the accuracy of an active contour modelfor estimating the posterior ablative margin in images obtained by the fusion of real-timeultrasonography (US) and 3-dimensional (3D) US or magnetic resonance (MR) images of anexperimental tumor model for radiofrequency ablation. Methods: Chickpeas (n=12) and bovine rump meat (n=12) were used as an experimental tumormodel. Grayscale 3D US and T1-weighted MR images were pre-acquired for use as referencedatasets. US and MR/3D US fusion was performed for one group (n=4), and US and 3D USfusion only (n=8) was performed for the other group. Half of the models in each group werecompletely ablated, while the other half were incompletely ablated. Hyperechoic ablation areaswere extracted using an active contour model from real-time US images, and the posteriormargin of the ablation zone was estimated from the anterior margin. After the experiments, theablated pieces of bovine rump meat were cut along the electrode path and the cut planes werephotographed. The US images with the estimated posterior margin were compared with thephotographs and post-ablation MR images. The extracted contours of the ablation zones from 12US fusion videos and post-ablation MR images were also matched. Results: In the four models fused under real-time US with MR/3D US, compression from thetransducer and the insertion of an electrode resulted in misregistration between the realtime US and MR images, making the estimation of the ablation zones less accurate than wasachieved through fusion between real-time US and 3D US. Eight of the 12 post-ablation 3DUS images were graded as good when compared with the sectioned specimens, and 10 of the12 were graded as good in a comparison with nicotinamide adenine dinucleotide staining andhistopathologic results. Conclusion: Estimating the posterior ablative margin using an active contour model is a feasibleway of predicting the ablation area, and US/3D US fusion was more accurate than US/MR fusion.

Angled Cool-Tip Electrode for Radiofrequency Ablation of Small Superficial Subcapsular Tumors in the Liver: A Feasibility Study

Park, Sung Il,Kim, Il Jung,Lee, Shin Jae,Shin, Min Woo,Shin, Won Sun,Chung, Yong Eun,Kim, Gyoung Min,Kim, Man Deuk,Won, Jong Yun,Lee, Do Yun,Choi, Jin Sub,Han, Kwang-Hyub The Korean Society of Radiology 2016 KOREAN JOURNAL OF RADIOLOGY Vol.17 No.5

<P><B>Objective</B></P><P>To evaluate the feasibility of angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular liver tumors abutting abdominal wall, in order to traverse normal liver parenchyma, and thereby, obtain favorable configuration of ablation margin.</P><P><B>Materials and Methods</B></P><P>In this study, we retrospectively analyzed 15 small superficial subcapsular liver tumors abutting abdominal wall in 15 patients, treated with radiofrequency ablation from March 2013 to June 2015 using a cool-tip electrode manually modified to create 25–35° angle at the junction between exposed and insulated segments. The tumors were hepatocellular carcinoma (n = 13) and metastases (n = 2: cholangiocellular carcinoma and rectosigmoid cancer), with maximum diameter of 10–26 mm (mean, 15.68 ± 5.29 mm). Under ultrasonographic guidance, the electrode tip was advanced to the depth of the tumors' epicenter about 1 cm from the margin. The tip was re-directed to penetrate the tumor for radiofrequency ablation. Minimal ablation margin was measured at immediate post-treatment CT. Radiological images and medical records were evaluated for success rate, length of minimal ablation margin and complications.</P><P><B>Results</B></P><P>Technical success rate of obtaining complete necrosis of the tumors was 100%, with no procedure-related complication. Minimal ablation margin ranged from 3–12 mm (mean, 7.07 ± 2.23 mm). CT/MRI follow-up at 21–1022 days (mean, 519.47 ± 304.51 days) revealed no local recurrence, but distant recurrence in 9 patients.</P><P><B>Conclusion</B></P><P>Using an angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular tumors abutting abdominal wall may be a feasible technique for obtaining adequate ablation margin and lower complication rate.</P>

Angled Cool-Tip Electrode for Radiofrequency Ablation of Small Superficial Subcapsular Tumors in the Liver: A Feasibility Study

박성일,김일중,이신재,신민우,신원선,정용은,김경민,김만득,원종윤,이도연,최진섭,한광협 대한영상의학회 2016 Korean Journal of Radiology Vol.17 No.5

Objective: To evaluate the feasibility of angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular liver tumors abutting abdominal wall, in order to traverse normal liver parenchyma, and thereby, obtain favorable configuration of ablation margin. Materials and Methods: In this study, we retrospectively analyzed 15 small superficial subcapsular liver tumors abutting abdominal wall in 15 patients, treated with radiofrequency ablation from March 2013 to June 2015 using a cool-tip electrode manually modified to create 25–35° angle at the junction between exposed and insulated segments. The tumors were hepatocellular carcinoma (n = 13) and metastases (n = 2: cholangiocellular carcinoma and rectosigmoid cancer), with maximum diameter of 10–26 mm (mean, 15.68 ± 5.29 mm). Under ultrasonographic guidance, the electrode tip was advanced to the depth of the tumors’ epicenter about 1 cm from the margin. The tip was re-directed to penetrate the tumor for radiofrequency ablation. Minimal ablation margin was measured at immediate post-treatment CT. Radiological images and medical records were evaluated for success rate, length of minimal ablation margin and complications. Results: Technical success rate of obtaining complete necrosis of the tumors was 100%, with no procedure-related complication. Minimal ablation margin ranged from 3–12 mm (mean, 7.07 ± 2.23 mm). CT/MRI follow-up at 21–1022 days (mean, 519.47 ± 304.51 days) revealed no local recurrence, but distant recurrence in 9 patients. Conclusion: Using an angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular tumors abutting abdominal wall may be a feasible technique for obtaining adequate ablation margin and lower complication rate.

Prevalence and Characteristics of Atrial Tachycardia From Noncoronary Aortic Cusp During Atrial Fibrillation Catheter Ablation

Myung-Jin Cha,Jun Kim,Yoon Jung Park,Min Soo Cho,Hyoung-Seob Park,Soonil Kwon,Young Soo Lee,Jinhee Ahn,Hyung-Oh Choi,Jong-Sung Park,YouMi Hwang,Jin Hee Choi,Ki-Won Hwang,Yoo-Ri Kim,Seongwook Han,Seil 대한심장학회 2022 Korean Circulation Journal Vol.52 No.7

Background and Objectives: Atrial tachycardias (ATs) from noncoronary aortic cusp (NCC) uncovered after radiofrequency ablation for atrial fibrillation (AF) are rarely reported. This study was conducted to investigate the prevalence and clinical characteristics of NCC ATs detected during AF ablation and compare their characteristics with de novo NCC ATs without AF. Methods: Consecutive patients who underwent radiofrequency catheter ablation for AF were reviewed from the multicenter AF ablation registry of 11 tertiary hospitals. The clinical and electrophysiological characteristics of NCC AT newly detected during AF ablation were compared with its comparators (de novo NCC AT ablation cases without AF). Results: Among 10,178 AF cases, including 1,301 redo ablation cases, 8 (0.08%) NCC AT cases were discovered after pulmonary vein isolation (PVI; 0.07% in first ablation and 0.15% in redo ablation cases). All ATs were reproducibly inducible spontaneously or with programmed atrial stimulation without isoproterenol infusion. The P-wave morphological features of tachycardia were variable depending on the case, and most cases exhibited 1:1 atrioventricular conduction. AF recurrence rate after PVI and NCC AT successful ablation was 12.5% (1 of 8). Tachycardia cycle length was shorter than that of 17 de novo ATs from NCC (303 versus 378, p=0.012). No AV block occurred during and after successful AT ablation. Conclusions: Uncommon NCC ATs (0.08% in AF ablation cases) uncovered after PVI, showing different characteristics compared to de-novo NCC ATs, should be suspected irrespective of P-wave morphologies when AT shows broad propagation from the anterior interatrial septum.

A Hybrid Procedure for Atrial Fibrillation Using Total Thoracoscopic Ablation and Post-Procedural Electrophysiological Confirmation of Ablation Lines

정동섭,정재한,박표원,이영탁,박승정,김준수,온영근 대한심장학회 2013 Korean Circulation Journal Vol.43 No.6

Atrial fibrillation (AF) is the most common chronic arrhythmia in the world, and it is associated with an increased long-term risk of stroke,heart failure, and all-cause mortality. To overcome the limitations of transvenous radiofrequency (RF) ablation for AF, total thoracoscopic ablation (TTA) has evolved as a new technique. TTA has several advantages over transvenous RF ablation and is known to produce better outcomes, especially in patients with persistent AF. Herein, we report 2 cases of successful TTA followed by an electrophysiological study confirming satisfactory ablation lines; the first such procedure reported in Korea. Atrial fibrillation (AF) is the most common chronic arrhythmia in the world, and it is associated with an increased long-term risk of stroke,heart failure, and all-cause mortality. To overcome the limitations of transvenous radiofrequency (RF) ablation for AF, total thoracoscopic ablation (TTA) has evolved as a new technique. TTA has several advantages over transvenous RF ablation and is known to produce better outcomes, especially in patients with persistent AF. Herein, we report 2 cases of successful TTA followed by an electrophysiological study confirming satisfactory ablation lines; the first such procedure reported in Korea. (

2018 심방세동 카테터 절제술 대한민국 진료지침: Part II

유희태,정동섭,박희남,박형섭,김주연,김준,이정명,김기훈,윤남식,노승영,오용석,조영진,심재민 대한부정맥학회 2018 International Journal of Arrhythmia Vol.19 No.3

In this part the writing group will cover strategies, techniques, and endpoints of atrial fibrillation (AF) ablation. Prior to all, electrical isolation of the pulmonary veins is recommended during all AF ablation procedures. In addition, techniques to be used for ablation of persistent and long-standing persistent AF, adjunctive ablation strategies, nonablative strategies to improve outcomes of AF ablation, and endpoints for ablation of paroxysmal, persistent, and long-standing persistent AF will be reviewed. Currently many technologies and tools are employed for AF ablation procedures. Radiofrequency energy, cryoablation, and other energy sources and tools are in various stages of development and/or clinical investigation. Finally, anticoagulation strategies pre-, during, and postcatheter ablation of AF and technical aspects of ablation to maximize safety are discussed in this section.

The Effect of 0.02% Mitomycin C Injection into the Hair Follicle with Radiofrequency Ablation in Trichiasis Patients

김규남,유웅선,김성재,한용섭,정인영,박종문,유지명,서성욱 대한안과학회 2014 Korean Journal of Ophthalmology Vol.28 No.1

Purpose: To investigate the inhibitory effect of 0.02% mitomycin C on eyelash regrowth when injected to theeyelash hair follicle immediately after radiofrequency ablation. Methods: We prospectively included 21 trichiasis patients from June 2011 to October 2012. Twenty eyes of 14patients were treated with 0.02% mitomycin C to the hair follicle immediately after radiofrequency ablation ingroup 1, while radiofrequency ablation only was conducted in ten eyes of seven patients in group 2. Recurrencesand complications were evaluated until six months after treatment. Results: One hundred sixteen eyelashes of 20 eyes in group 1 underwent treatment, and 19 (16.4%) eyelashesrecurred. Eighty-four eyelashes of ten eyes in group 2 underwent treatment, and 51 (60.7%) eyelashes recurred. No patients developed any complications related to mitomycin C. Conclusions: Application of 0.02% mitomycin C in conjunction with radiofrequency ablation may help to improvethe success rate of radiofrequency ablation treatment in trichiasis patients.

Recent Advances in the Image-Guided Tumor Ablation of Liver Malignancies: Radiofrequency Ablation with Multiple Electrodes, Real-Time Multimodality Fusion Imaging, and New Energy Sources

이동호,이정민 대한영상의학회 2018 Korean Journal of Radiology Vol.19 No.4

Radiofrequency ablation (RFA) has emerged as an effective loco-regional treatment modality for malignant hepatic tumors. Indeed, studies have demonstrated that RFA of early stage hepatocellular carcinomas can provide comparable overall survival to surgical resection. However, the incidence of local tumor progression (LTP) after RFA is significantly higher than that of surgical resection. Thus, to overcome this limitation, multiple electrode radiofrequency (RF) systems that use a multi-channel RF generator have been developed, and they demonstrate better efficiency in creating larger ablation zones than that using the conventional RFA with a single electrode. Furthermore, RFA with multiple electrodes can allow the “notouch” ablation technique which may also help to reduce LTP. Another technique that would be helpful in this regard is multi-modality-ultrasound fusion imaging, which helps to not only more accurately determine the target lesion by enabling the RFA of small, poorly visible or invisible tumors, but also improve the monitoring of procedures and determine the appropriateness of the ablation margin. In addition, new energy sources, including microwave and cryoablation, have been introduced in imaging-guided tumor ablation. In this review, these recently introduced ablation techniques and the results of the most current animal and clinical studies are discussed.

No-Touch Radiofrequency Ablation: A Comparison of Switching Bipolar and Switching Monopolar Ablation in Ex Vivo Bovine Liver

장원,이정민,이상민,한준구 대한영상의학회 2017 Korean Journal of Radiology Vol.18 No.2

Objective: To evaluate the feasibility, efficiency, and safety of no-touch switching bipolar (SB) and switching monopolar (SM) radiofrequency ablation (RFA) using ex vivo bovine livers. Materials and Methods: A pork loin cube was inserted as a tumor mimicker in the bovine liver block; RFA was performed using the no-touch technique in the SM (group A1; 10 minutes, n = 10, group A2; 15 minutes, n = 10) and SB (group B; 10 minutes, n = 10) modes. The groups were compared based on the creation of confluent necrosis with sufficient safety margins, the dimensions, and distance between the electrode and ablation zone margin (DEM). To evaluate safety, small bowel loops were placed above the liver surface and 30 additional ablations were performed in the same groups. Results: Confluent necroses with sufficient safety margins were created in all specimens. SM RFA created significantly larger volumes of ablation compared to SB RFA (all p < 0.001). The DEM of group B was significantly lower than those of groups A1 and A2 (all p < 0.001). Although thermal injury to the small bowel was noted in 90%, 100%, and 30% of the cases in groups A1, A2, and B, respectively, full depth injury was noted only in 60% of group A2 cases. Conclusion: The no-touch RFA technique is feasible in both the SB and SM modes; however, SB RFA appears to be more advantageous compared to SM RFA in the creation of an ablation zone while avoiding the unnecessary creation of an adjacent parenchymal ablation zone or adjacent small bowel injuries.