The therapeutic effectiveness and safety of radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC) have been clinically established, and the procedure is now generally accepted as a curative treatment for very early or early stage HCC. Recently, we observed an aggressive recurrence after RFA for HCC in 50 year-old female. RFA was performed for a 2.7 cm sized HCC, which was completely ablated. However, 7 months later, aggressive intrahepatic recurrence was observed. Herein, we report a case with a discussion.
Ablation Techniques ; Carcinoma, Hepatocellular* ; Catheter Ablation* ; Female ; Humans ; Recurrence

As a novel tumor therapy, pulse electric field has shown a clinical perspective. This paper reviews the characteristics of tumor ablation by microsecond pulse and nanosecond pulse electric field, and the research advances of anti-tumor immune response induced by pulse electric field ablation. Recent researches indicate that the pulse electric field not only leads to a complete ablation of local tumor, but also stimulates a protective immune response, thereby inhibiting tumor recurrence and metastasis. These unique advantages will show an extensive clinical application in the future. However, the mechanism of anti-tumor immune response and the development of related tumor vaccine need further studies.
Ablation Techniques ; Electricity ; Humans ; Neoplasms ; immunology ; therapy

BACKGROUND: To achieve a prolonged therapeutic effect in patients with lumbar facet joint syndrome, radiofrequency medial branch neurotomy (RF-MB) is commonly performed. The purpose of this study was to evaluate the prognostic value of paravertebral muscle twitching when performing RF-MB in patients with lumbar facet joint syndrome. METHODS: We collected and analyzed data from 68 patients with confirmed facet joint syndrome. Sensory stimulation was performed at 50 Hz with a 0.5 V cut-off value. Patients were divided into 3 groups according to the twitching of the paravertebral muscle during 2 Hz motor stimulation: ‘Complete’, when twitching was observed at all needles; ‘Partial’, when twitching was present at 1 or 2 needles; and ‘None’, when no twitching was observed. The relationship between the long-term effects of RF-MB and paravertebral muscle twitching was analyzed. RESULTS: The mean effect duration of RF-MB was 4.6, 5.8, and 7.0 months in the None, Partial, and Complete groups, respectively (P = 0.47). Although the mean effect duration of RF-MB did not increase significantly in proportion to the paravertebral muscle twitching, the Complete group had prolonged effect duration (> 6 months) than the None group in subgroup analysis. (P = 0.03). CONCLUSIONS: Paravertebral muscle twitching while performing lumbar RF-MB may be a reliable predictor of long-term efficacy when sensory provocation under 0.5 V is achieved. However, further investigation may be necessary for clarifying its clinical significance.
Ablation Techniques ; Catheter Ablation ; Fasciculation ; Humans ; Low Back Pain ; Needles ; Prognosis ; Zygapophyseal Joint

In the treatment of benign thyroid nodules, ethanol ablation (EA), and radiofrequency ablation (RFA) have been suggested for cystic and solid thyroid nodules, respectively. Although combining these ablation techniques may be effective, no guidelines for or reviews of the combination have been published. Currently, there are three ways of combining EA and RFA: additional RFA is effective for treatment of incompletely resolved symptoms and solid residual portions of a thyroid nodule after EA. Additional EA can be performed for the residual unablated solid portion of a nodule after RFA if it is adjacent to critical structures (e.g., trachea, esophagus, and recurrent laryngeal nerve). In the concomitant procedure, ethanol is injected to control venous oozing after aspiration of cystic fluid prior to RFA of the remaining solid nodule.
Ablation Techniques ; Catheter Ablation* ; Esophagus ; Ethanol* ; Thyroid Gland* ; Thyroid Nodule* ; Trachea

We report two cases of needle-tract seeding after cryoablation and radiofrequency ablation for hepatocellular carcinomas. The seeding nodule appeared 6 and 12 months on the follow-up computed tomographic scan, respectively. In both cases, the seeding nodules were solitary in the chest wall, and could be completely resected.
Ablation Techniques ; Carcinoma, Hepatocellular ; Catheter Ablation ; Cryosurgery ; Follow-Up Studies ; Thoracic Wall ; Thorax

PURPOSE: The purpose of this study was to evaluate the accuracy of an active contour model for estimating the posterior ablative margin in images obtained by the fusion of real-time ultrasonography (US) and 3-dimensional (3D) US or magnetic resonance (MR) images of an experimental tumor model for radiofrequency ablation. METHODS: Chickpeas (n=12) and bovine rump meat (n=12) were used as an experimental tumor model. Grayscale 3D US and T1-weighted MR images were pre-acquired for use as reference datasets. US and MR/3D US fusion was performed for one group (n=4), and US and 3D US fusion only (n=8) was performed for the other group. Half of the models in each group were completely ablated, while the other half were incompletely ablated. Hyperechoic ablation areas were extracted using an active contour model from real-time US images, and the posterior margin of the ablation zone was estimated from the anterior margin. After the experiments, the ablated pieces of bovine rump meat were cut along the electrode path and the cut planes were photographed. The US images with the estimated posterior margin were compared with the photographs and post-ablation MR images. The extracted contours of the ablation zones from 12 US 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 the transducer and the insertion of an electrode resulted in misregistration between the real-time US and MR images, making the estimation of the ablation zones less accurate than was achieved through fusion between real-time US and 3D US. Eight of the 12 post-ablation 3D US images were graded as good when compared with the sectioned specimens, and 10 of the 12 were graded as good in a comparison with nicotinamide adenine dinucleotide staining and histopathologic results. CONCLUSION: Estimating the posterior ablative margin using an active contour model is a feasible way of predicting the ablation area, and US/3D US fusion was more accurate than US/MR fusion.
Ablation Techniques ; Catheter Ablation* ; Cicer ; Dataset ; Electrodes ; Meat ; NAD ; Shadowing (Histology) ; Transducers ; Ultrasonography*

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 “no-touch” 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.
Ablation Techniques ; Animals ; Carcinoma, Hepatocellular ; Catheter Ablation* ; Cryosurgery ; Electrodes* ; Incidence ; Liver* ; Microwaves

BACKGROUND: Radiofrequency catheter ablation was introduced the curative method of supraventricular tachycardia in patients with accessory pathways. The success of catheter ablation depends on the accurate localization of accessory pathway and the destruction of accessory pathways. METHOD: We analyzed the local electrograms in 35 patients to be underwent the successful catheter ablation and measured the catheter stability, A/V ratio, AV interval, Accessory pathway potential, and the interval from the onset of RF energy to loss of accessory pathway from local electrograms at the successful ablation sites. RESULTS: The ratio of A wave and V wave range from 0.06 to 6.33 and the mean of A/V ratio is 0.62. The shortest AoVo interval is 20 msec and the longest AoVo interval is 120 msec and the mean of AoVo interval is 58.23 msec. The shortest ApVp interval is 20 msec and the longest ApVp interval is 100 msec and the mean of this interval is 51.88 msec. The incidence of accessory pathway potential among 35 successful ablation sites in 25%. The mean of time from RF energy to loss of accessory pathway is 4.48 sec. CONCLUSION: We concluded that the finding of local electrogram during catheter ablation is very important for shortening of procedure time and the successful procedure.
Catheter Ablation* ; Catheters ; Electrophysiologic Techniques, Cardiac* ; Humans ; Incidence ; Tachycardia, Supraventricular

Percutaneous ethanol injection (PEI) therapy has been replaced by more-effective thermal ablation techniques that have lower local recurrence rates. However, PEI therapy remains useful in certain settings. Since PEI can be performed in any portion of the liver, PEI therapy can be valuable when tumors are located in close proximity to intestinal loops or other positions that are risky for thermal local ablative techniques. PEI therapy is also valuable in other situations where radiofrequency ablation (RFA) is difficult, including technically difficult masses that are not detected with ultrasound (US), are located in the hepatic dome, in the subcapsular area, and exophytically, or are surrounded by large vessels. PEI therapy contributes to combination therapy with transcatheter arterial chemoembolization or RFA in advanced-stage hepatocellular carcinoma (HCC), and also to the treatment of large HCC or extrahepatic metastasis from HCC. These roles of PEI therapy should be stressed for the treatment of HCCs in appropriate clinical situations. This comprehensive review of articles related to PEI therapy illustrates the recent role and indications of this therapy, which is currently valuable for HCC in the era of RFA.
Ablation Techniques ; Carcinoma, Hepatocellular ; Ethanol ; Liver ; Neoplasm Metastasis ; Recurrence

BACKGROUND: Catheter ablation of accessory pathways using radiofrequency(RF) energy was recently introduced to cure accessory pathway related tachyarrhythmias. The purpose of the present study was to evaluate the efficacy and safety of radiofrequency catheter ablation of accessory pathways and to determine factors influencing the outcome of catheter ablation. METHODS: Electrophysiology study was performed with standard technique and catheter ablation of accessory pathways using RF and conventional ablation technique. The outcome of RF catheter ablation were evaluated according to the location and the overtness of accessory pathways. Eighty patients(Mean +/-SD age, 36+/-15 years ; 50 male, 30 female)comprising 49(61%) with Wolff-Parkinson-White(WPW) syndrome and 31(39%) with atrioventricular reentry tachycardia(AVRT) using concealed bypass tract underwent RF catheter ablation for total of 85 accessory pathways in the Chonnam University Hospital. Five(6.3%) patients had multiple accessory pathways. RESULTS: Seventy-nine(92.9%) out of 85 pathways and all the pathways in 75(93.8%) out of 80 patients were ablated successfully. The success rate showed no significant difference between patients with overt accessory pathways and patients with concealed accessory pathways(92.0% vs. 93.9%). However, the success rate in right free wall location(72.7% of 11) was significantly lower than that in the other sites (95.9% of 74, p<0.05). More attempts were tried to ablate right-sided accessory pathway than left-sided pathways(6.4+/-24.1 vs. 3.8+/-6.8, p<0.05). Three(3.8%) pathways recurred within 30 minutes after the initial successful ablation. Four(5.1%) pathways recurred from 16 hours to 7 months after completion of the initial successful ablation session during the mean follow-up period of 43+/-24 weeks(range, 2-84 weeks). This late recurrence was more frequent, although statistically insignificant, in right-sided accessory pathways(11.1% vs. 3.3%, p=0.22). All 4 recurrent pathways(1 at the same session, 3 at the repeated sessions) reattempted for ablation were successfully ablated. As procedure-related complications, second degree AV block developed in a patients with mid septal and posteroseptal pahways and hemopericardium in a patients with a left anterolateral pathway. CONCLUSION: RF catheter ablation of atrioventricular accessory pathways is very effective and safe, with a success rate of 93.8% and a complication rate of 2.5%. Right-sided accessory pathways are more difficult to ablate than left-sided accessory pathways, requiring the development of a better technique for right free wall pathways.
Ablation Techniques ; Atrioventricular Block ; Catheter Ablation* ; Catheters* ; Electrophysiology ; Follow-Up Studies ; Humans ; Jeollanam-do ; Male ; Pericardial Effusion ; Recurrence ; Tachycardia