Radiofrequency Ablation

The following on surveillance and reversal of Barrett's esophagus (BE) includes commentaries on criteria for surveillance even when squamous epithelium stains normally with a variety of biomarkers; the long‐term follow‐up of surgery versus endoscopic ablation of BE; the recommended surveillance intervals in patients without dysplasia; the sampling problems related to anatomic changes following fundoplication; the value of tissue spectroscopy and optical coherence tomography; the cost‐effectiveness of biopsy protocols for surveillance; the quality of life of Barrett's patients; and risk stratification and surveillance strategies.

Purpose This multicenter phase I/II study evaluated the safety, feasibility, and initial efficacy of radiofrequency ablation (RFA) for small malignant renal tumors. Methods Thirty-three patients were enrolled in the study. A single session of RFA was performed in patients with a renal tumor of 1-3 cm in greatest diameter, with the exception of lesions adjacent to the renal hilum. The primary endpoint was the safety of renal RFA, and the secondary endpoints were its feasibility and initial efficacy for local control, as well as the incidence and grade of adverse events. Clinical efficacy was evaluated by CT scans within 1 week and at a further 4 weeks after the procedure using the criteria adapted from the Response Evaluation Criteria in Solid Tumors. The RFA procedure was completed in 100 % (95 % confidence interval [CI] 89-100 %) of all 33 patients. There were no severe adverse events (0 % [95 % CI 0-11 %]). Among the 33 patients, a complete response, partial response, progressive disease, and stable disease were seen in 28 (85 %), 0 (0 %), one (3 %), and one (3 %) patient(s), respectively, with a tumor response rate of 85 % [95 % CI 68-95 %]). Three patients (9 %), including one ineligible patient (3 %), were not evaluable. Out of 30 evaluable patients, a complete response was achieved in 28 (93 %). Conclusion The current multicenter trial revealed that RFA is a safe, feasible, and effective treatment for small malignant renal tumors in patients who are not candidates for surgery.

This multicenter phase I/II study evaluated the safety, feasibility, and initial efficacy of radiofrequency ablation (RFA) for small malignant renal tumors. Thirty-three patients were enrolled in the study. A single session of RFA was performed in patients with a renal tumor of 1-3 cm in greatest diameter, with the exception of lesions adjacent to the renal hilum. The primary endpoint was the safety of renal RFA, and the secondary endpoints were its feasibility and initial efficacy for local control, as well as the incidence and grade of adverse events. Clinical efficacy was evaluated by CT scans within 1 week and at a further 4 weeks after the procedure using the criteria adapted from the Response Evaluation Criteria in Solid Tumors. The RFA procedure was completed in 100 % (95 % confidence interval [CI] 89-100 %) of all 33 patients. There were no severe adverse events (0 % [95 % CI 0-11 %]). Among the 33 patients, a complete response, partial response, progressive disease, and sta...

The aim of the study was to investigate the conduction properties and anisotropy of the crista terminalis (CT) in patients with atrial flutter (AFL) using non-contact mapping. BACKGROUND The CT is a posterior barrier during typical AFL. However, the CT has transverse conduction capabilities in patients with upper loop re-entry (ULR). Twenty-two patients (16 males, 63 Ϯ 15 years) with typical AFL and ULR were included. Non-contact mapping of the right atrium during AFL and pacing from coronary sinus (CS) and low anterolateral right atrium (LARA) was performed to evaluate transverse conduction across the CT. During ULR, the longitudinal (CV L ) and transverse (CV T ) conduction velocity along and across the CT were measured. The width of the CT conduction gap was evaluated to guide radiofrequency ablation (RFA). No transverse CT gap conduction was found during typical AFL. Transverse CT gap conduction was found in three patients during CS pacing and in three patients during LARA pacing. During ULR, CV L was greater than CV T (1.28 Ϯ 0.43 vs. 0.73 Ϯ 0.30 m/s, p Ͻ 0.001). The CV L /CV T ratio was 1.95 Ϯ 0.77, which was inversely related to the CT gap width (15.7 Ϯ 6.8 mm) (p Ͻ 0.001). The RFA of the CT gap was successful in 18 patients. Four patients had recurrence of arrhythmias during the follow-up of 11 Ϯ 3 months. CONCLUSIONS Most of the CT conduction gaps were functional and only appeared during ULR. The width of the CT gap was inversely related to the anisotropic ratio of the CT. The RFA of the CT gap was effective in eliminating ULR. (

Background: Renal denervation with radiofrequency ablation has become an accepted treatment for drug-resistant hypertension. However, there is a continuing need to develop new catheters for high-accuracy, targeted ablation. We, therefore, developed a radiofrequency ablation device with a basket catheter and bipolar electrodes for controlled, targeted ablation through Joule heating induction between 60°C and 100°C.Methods: Finite element modeling was used to determine the optimum catheter design to deliver a minimum ablation zone of 4 mm (W) x 10 mm (L) x 4 mm (H) within 60 seconds with a 500 kHz, 60 Vp-p signal, and 0.9 W maximum. The computational model was validated using in vitro phantom tissue impregnated with a color-changing thermochromic pigment.Results: The in vitro ablation zone closely matched the size and shape of the simulated area. The new electrode design directs the current density towards the artery walls and tissue, reducing unwanted blood temperature increases by f...

Background Renal denervation with radiofrequency ablation has become an accepted treatment for drug-resistant hypertension. However, there is a continuing need to develop new catheters for high-accuracy, targeted ablation. We therefore developed a radiofrequency bipolar electrode for controlled, targeted ablation through Joule heating induction between 60 and 100 °C. The bipolar design can easily be assembled into a basket catheter for deployment inside the renal artery. Methods Finite element modeling was used to determine the optimum catheter design to deliver a minimum ablation zone of 4 mm (W) × 10 mm (L) × 4 mm (H) within 60 s with a 500 kHz, 60 Vp-p signal, and 3 W maximum. The in silico model was validated with in vitro experiments using a thermochromic phantom tissue prepared with polyacrylamide gel and a thermochromic ink additive that permanently changes from pink to magenta when heated over 60 °C. Results The in vitro ablation zone closely matched the size and shape of th...

RF Ablation of VT in Chronic Cocaine UsersBackgroundCocaine use is a known but rare cause of cardiac arrhythmias. Ventricular arrhythmias related to cocaine may not respond to antiarrhythmic drugs and may need treatment with radiofrequency ablation.ObjectivesWe describe the clinical and electrophysiological characteristics of cocaine‐related ventricular tachycardia (VT) from a multicenter registry.MethodsSubjects presenting with VT related to cocaine use and being considered for radiofrequency ablation have been included in the study. Patients who were refractory to maximal medical therapy underwent radiofrequency ablation of the VT. Clinical, procedural variables, efficacy, and safety outcomes were assessed.ResultsA total of 14 subjects met study criteria (age 44 ± 13, range 18‐ to 68‐year‐old with 79% male, 71% Caucasian). MRI showed evidence of scar only in 43% of patients (6/14). The mechanism of VT was focal in 50% (n = 7) and scar related reentry in 50% (n = 7) based on 3D map...

Local ablative techniques have been developed to enable local control of unresectable tumors. Ablation has been performed with several modalities including ethanol ablation, laser ablation, cryoablation, and radiofrequency ablation. Microwave technology is a new thermal ablation technique for different types of tumors, providing all the benefits of radiofrequency and substantial advantages. Microwave ablation has been applied to liver, lung, kidney and more rarely to bone, pancreas and adrenal glands. Preliminary works show that microwave ablation may be a viable alternative to other ablation techniques in selected patients. However further studies are necessary to confirm short-and long-term effectiveness of the methods and to compare it with other ablative techniques, especially RF.

Purpose. After radiofrequency ablation (RFA) of hepatocellular carcinoma (HCC), pre-and postinterventional contrast-enhanced CT (CECT) images are usually qualitatively interpreted to determine technical success, by eyeballing. e objective of this study was to evaluate the feasibility of quantitative assessment, using a nonrigid CT-CT coregistration algorithm. Materials and Methods. 25 patients treated with RFA for HCC between 2009 and 2014 were retrospectively included. Semiautomated coregistration of pre-and posttreatment CECT was performed independently by two radiologists. In scans with a reliable registration, the tumor and ablation area were delineated to identify the side and size of narrowest RFA margin. In addition, qualitative assessment was performed independently by two other radiologists to determine technical success and the anatomical side and size of narrowest margin. Interobserver agreement rates were determined for both methods, and the outcomes were compared with occurrence of local tumor progression (LTP). Results. CT-CT coregistration was technically feasible in 18/25 patients with almost perfect interobserver agreement for quantitative analysis (κ � 0.88). e interobserver agreement for qualitative RFA margin analysis was κ � 0.64. Using quantitative assessment, negative ablative margins were found in 12/18 patients, with LTP occurring in 8 of these patients. In the remaining 6 patients, quantitative analysis demonstrated complete tumor ablation and no LTP occurred. Conclusion. Feasibility of quantitative RFA margin assessment using nonrigid coregistration of pre-and postablation CT is limited, but appears to be a valuable tool in predicting LTP in HCC patients (p � 0.013).

Purpose To investigate the biodistribution of holmium-166 microspheres (166Ho-MS) when administered after radiofrequency ablation (RFA) of early-stage hepatocellular carcinoma (HCC). The aim is to establish a perfused liver administration dose that results in a tumoricidal dose of holmium-166 on the hyperaemic zone around the ablation necrosis (i.e. target volume). Materials and Methods This is a multicentre, prospective, dose-escalation study in HCC patients with a solitary lesion 2–5 cm, or a maximum of 3 lesions of ≤ 3 cm each. The day after RFA patients undergo angiography and cone-beam CT (CBCT) with (super)selective infusion of technetium-99 m labelled microalbumin aggregates (99mTc-MAA). The perfused liver volume is segmented from the CBCT and 166Ho-MS is administered to this treatment volume 5–10 days later. The dose of holmium-166 is escalated in a maximum of 3 patient cohorts (60 Gy, 90 Gy and 120 Gy) until the endpoint is reached. SPECT/CT is used to determine the biodist...

Focal pancreatic lesions include a heterogeneous group of solid and cystic lesions, with different natures and variable clinical, imagiological, and pathological characteristics. Several endoscopic ultrasound (EUS)-guided ablative techniques have been tested during the last decade for the treatment of these pancreatic lesions, mostly consisting of the injection of ablative agents and, more recently, radiofrequency ablation. The most encouraging EUS-guided ablation outcomes are being reached in the treatment of some pancreatic cystic neoplasms and small (≤2 cm) pancreatic neuroendocrine tumours (pNETs). Data supporting a potential role of ablative therapies in the treatment of pancreatic ductal adenocarcinoma is still lacking. In this article, GRUPUGE presents an updated perspective of the potential role of EUS-guided ablation for the treatment of pancreatic cystic neoplasms and pNETs, addressing the selection criteria and technical issues of different techniques and analysing recent data on their safety and efficacy.

Focal pancreatic lesions include a heterogeneous group of solid and cystic lesions, with different natures and variable clinical, imagiological, and pathological characteristics. Several endoscopic ultrasound (EUS)-guided ablative techniques have been tested during the last decade for the treatment of these pancreatic lesions, mostly consisting of the injection of ablative agents and, more recently, radiofrequency ablation. The most encouraging EUS-guided ablation outcomes are being reached in the treatment of some pancreatic cystic neoplasms and small (≤2 cm) pancreatic neuroendocrine tumours (pNETs). Data supporting a potential role of ablative therapies in the treatment of pancreatic ductal adenocarcinoma is still lacking. In this article, GRUPUGE presents an updated perspective of the potential role of EUS-guided ablation for the treatment of pancreatic cystic neoplasms and pNETs, addressing the selection criteria and technical issues of different techniques and analysing recent...

Current management of atrial fibrillation (AF) refractory to pharmacological therapy involves the creation of lines of conduction block in the atrial tissue either by direct surgical incision or fluoroscopy guided radiofrequency (RF) ablation. While these techniques have been shown to be effective in terminating atrial fibrillation, open heart surgery carries considerable inherent risk and fluoroscopy guided approaches are technically difficult and result in extremely long radiation exposure times. Magnetic resonance (MR) guided ablation therapy may represent a safer and more practical alternative for creating lines of conduction block in patients with AF. We have developed a novel MR compatible system that permits simultaneous high resolution MR imaging, cardiac electrical mapping, and RF energy delivery. This system has, for the first time, made it possible to perform a comprehensive MR guided electrophysiology study including guidance, delivery, and monitoring of cardiac ablation therapy.

Study Design: Retrospective. Level IV Evidence. Objective: To assess the utility of intraoperative neurophysiological monitoring (IONM) to detect and eventually prevent impending neurovascular damage during computed tomography (CT)-guided radiofrequency ablation (RFA) of spinal osteoid osteoma (OO) in children. Summary and Background Data: To our knowledge, this is the first case series of spinal OO in pediatric patients treated at a single center employing IONM during RFA. Methods: This is a retrospective study of seven consecutive patients (3 girls and 4 boys, mean age: 9 years 4 months) with imaging and clinical signs compatible with spinal OO who underwent CT-guided RFA, under general anesthesia, and IONM in a single center between 2011 and 2015. Before the RFA procedure, a CT-guided percutaneous biopsy of the nidus was performed in the same setting. RFA was divided into four cycles of increasing time and temperature and performed under IONM in every patient. Results: Two patients had lesions located in the thoracic spine and five patients had lumbar involvement. The RFA technical and clinical success was 85.7%. Six patients presented with reversible neurophysiological changes either during biopsy needle positioning or RFA cycles. In the remaining case, as IONM changes did not improve after several minutes of neuroprotective hypertension, the procedure was interrupted. Neither neurologic nor vascular complications were observed after RFA treatment. In only one biopsy sample, OO was confirmed by histopathologic studies. Conclusion: CT-guided RFA is an accepted minimally invasive technique for the treatment of spinal OO in children. IONM may be a helpful tool that requires minimal additional time and provides feedback on the state of the spinal cord and nerves at risk during the procedure. We promote the use of IONM during these procedures to detect and possibly prevent impending neurologic damage. Level of Evidence: Level IV.

Purpose of Review Examining the efficacy of radiofrequency ablation in treating headache conditions. Recent Findings The efficacy of radiofrequency ablation in treating headache conditions is not well studied. Summary Chronic headache conditions can be difficult to treat with little consensus on management of headaches associated with pericranial neuralgias. In this retrospective study, we found that radiofrequency ablation is an effective and safe treatment for resistant headache conditions. This study is important as it describes a novel treatment for chronic headache which can benefit a large number of patients.

Our objective was to investigate whether increases in atmospheric or local tissue pressure would affect the outcome of radiofrequency ablation procedures and the size of the created thermal lesions. MATERIALS AND METHODS. Thermal lesions were produced in specimens of explanted bovine liver inside a hyperbaric chamber at 101 (atmospheric), 141, 202, 273, and 364 kPa using radiofrequency power settings of 20, 30, 40, and 50 W. In subsequent in vivo experiments, thermal lesions were produced in the livers of anesthetized pigs with or without occlusion of the hepatic vein draining the ablation site. RESULTS. At each radiofrequency power setting, progressive increases in applied pressure were paralleled by decreases in minimum impedance and increases in maximum tissue temperatures at the electrode tip (reflecting tissue-fluid boiling points), delivery time, total energy delivered, and thermal lesion volumes. Similar increases were observed in radiofrequency ablation procedures performed in vivo under occlusion of the vein draining the ablation site. CONCLUSION. By elevating the tissue-fluid boiling point, increased pressure delays the desiccation of tissue in contact with the radiofrequency electrode tip and the related sharp increase in impedance. The result is prolonged delivery of larger amounts of radiofrequency energy and larger thermal lesions.

Objective Radiofrequency ablation (RFA) of the medial branch nerve is a commonly performed procedure for patients with facet syndrome. RFA has previously been demonstrated to provide long-term functional improvement in approximately 50% of patients, including those who had significant pain relief after diagnostic medial branch block. We sought to identify factors associated with success of RFA for facet pain. Design Active-duty military patients who underwent lumbar RFA (L3, L4, and L5 levels) over a 3-year period were analyzed. Defense and Veterans Pain Rating Scale (DVPRS) and Oswestry Disability Index (ODI) scores were assessed the day of procedure and at the 2-month and 6-month follow-up. These data were analyzed to identify associations between patient demographics, pain, and functional status and patients’ improvement after RFA, with a primary outcome of ODI improvement and a secondary outcome of pain reduction. Results Higher levels of starting functional impairment (starting...

BACKGROUND Recurrent sustained ventricular tachycardia (VT) is not responsive to antiarrhythmic drugs in the majority of patients, who therefore need therapy with nonpharmacological methods. We evaluated prospectively the feasibility, safety, and efficacy of transcatheter radiofrequency (RF) ablation of VT in 21 selected patients with ischemic heart disease and VT. METHODS AND RESULTS Twenty-one patients with ischemic heart disease and recurrent, drug-refractory VT documented by 12-lead ECG were selected who had sufficient hemodynamic tolerance of VT to undergo transcatheter mapping. Documented clinical VT was reproduced by programmed cardiac stimulation (PCS), and the site of origin was localized by a combination of techniques, including pace mapping, activation-sequence mapping, recordings of middiastolic potentials, and application of resetting and entrainment principles. RF current at 55 V was applied (3.8 +/- 3.1 applications per patient) for as long as 30 seconds at a time to ...

Purpose: To optimize surveillance schedules for detecting recurrent hepatocellular carcinoma (HCC) after liver-directed therapy. Materials and Methods: New methods have emerged that allow quantitative analysis and optimization of surveillance schedules for diseases with substantial rates of recurrence such as HCC. We applied these methods to 1766 consecutive chemoembolization (TACE), radioembolization (RE), and radiofrequency ablation (RFA) procedures performed on 910 patients between 2006 and 2011. The CT or MRI obtained just prior to repeat therapy was set as the time of recurrence. "Recurrence" included residual and locally recurrent tumor, as well as new liver tumors. Time-to-recurrence distribution was estimated using Kaplan-Meier. Average diagnostic delay (time between recurrence and detection) was calculated for each proposed surveillance schedule, using the time-to-recurrence distribution. An optimized surveillance schedule could then be derived to minimize the average diagnostic delay. Results: Recurrence is 6.5 times more likely in the first year after treatment, compared to the second. Therefore, screening should be much more frequent in the first year. For 8 time points in the first 2 years of follow-up, the optimal schedule is 2, 4, 6, 8, 11, 14, 18, and 24 months. This schedule reduces diagnostic delay compared to published schedules, and is cost effective. The calculated optimal surveillance schedules include shorter interval follow-up when there is a higher probability of recurrence, and longer interval follow-up when there is a lower probability. Cost can be optimized for a specified acceptable diagnostic delay, or diagnostic delay can be optimized within a specified acceptable cost.

Biopsy is usually performed as the first step in percutaneous treatment of osteoid osteomas prior to laser photocoagulation. At our institution, 117 patients with a presumed diagnosis of osteoid osteoma had a trephine biopsy before a percutaneous laser photocoagulation. Biopsies were made using two different types of needles. A Bonopty biopsy needle (14-gauge cannula, 16-gauge trephine needle; Radi Medical Systems, Uppsala, Sweden) was used in 65 patients, and a Laurane biopsy needle (11gauge cannula, 12.5-gauge trephine needle; Laurane Medical, Saint-Arnoult, France) in 43 patients. Overall biopsy results were positive for osteoid osteoma in 83 (70.9%) of the 117 cases. The Laurane needle provided a significantly higher positive rate (81.4%) than the Bonopty needle (66.1%; p \\ 0.05). This difference was not due to the size of the nidus, which was similar in the two groups (p \\ 0.05) and may be an effect of differences in needle caliber (12.5 vs. 14 gauge) as well as differences in needle design. The rate of positive biopsy results obtained in the present series with the Laurane biopsy needle is, to our knowledge, the highest rate reported in series dealing with percutaneous radiofrequency ablation and laser photocoagulation of osteoid osteomas.

Background: When multiple treatments are available, network meta-analysis can synthesise evidence and rank relative effectiveness. We applied this approach to first-line treatments for paroxysmal atrial fibrillation (medical therapy, radiofrequency ablation or cryoballoon ablation). Individual trials were analysed based on the restricted mean survival time (RMST). Methods: Data Sources included PubMed and websites of regulatory agencies. Randomised controlled trials assessing first-line treatments for paroxysmal atrial fibrillation were selected. The end-point for our analysis was atrial fibrillation recurrence-free survival at 12 months. At least 2 reviewers abstracted study data and outcomes. Treatments examined for their relative effectiveness included medical therapy, radiofrequency ablation or cryoballoon ablation. Individual trials were examined based on restricted mean survival time (RMST). A Bayesian network meta-analysis was conducted to comparatively evaluate these treatments. Results: Five trials were included in the analysis: two compared radiofrequency with medical treatment and three cryoballoon with medical treatment. The indirect comparison of radiofrequency ablation vs cryoballoon ablation was assessed in the absence of RCTs. Differences in RMST (with 95% credible intervals) were estimated for all binary comparisons (direct or indirect). Radiofrequency and cryoballoon showed higher effectiveness compared with medical treatment, both at significant levels. In the indirect comparison, radiofrequency showed a numerical advantage over cryoballoon, that however remained far from significance. Ranking in effectiveness was as follows: 1) radiofrequency; 2) cryoballoon; 3) medical treatment. We generated an updated synthesis of these treatment effectiveness and we ranked them according to a Bayesian probabilistic model.

This article aims to compare available treatment options for type III liver hydatid cysts, including surgery and percutaneous techniques. Hydatid disease is a helminthic infection caused by Echinococcus granulosus and is a serious public health problem in endemic regions of the world. Hydatid cyst of the liver is the most common clinical presentation of Echinococcus granulosus. According to Gharbi classification, hydatid cysts of the liver are classified into 5 types. Type III hydatid cysts are those with fluid collection and septa. Treatment of Gharbi type III hydatid cysts is still controversial. Some researchers think that Gharbi type III hydatid cysts are not suitable for percutaneous drainage, and surgery is the suitable treatment option. There are not enough prospective studies comparing percutaneous and surgical techniques for the treatment of type III hydatid disease of the liver. A proper meta-analysis does not seem to be possible with the available studies in current medical literature.

Colorectal carcinoma (CRC) is the third most common cancer, and approximately 35%-55% of patients with CRC will develop hepatic metastases during the course of their disease. Surgical resection represents the only chance of long-term survival. The goal of surgery should be to resect all metastases with negative histological margins while preserving sufficient functional hepatic parenchyma. Although resection remains the only chance of long-term survival, management strategies should be tailored for each case. For patients with extensive metastatic disease who would otherwise be unresectable, the combination of advances in medical therapy, such as systemic chemotherapy (CTX), and the improvement in surgical techniques for metastatic disease, have enhanced prognosis with prolongation of the median survival rate and cure. The use of portal vein embolization and preoperative CTX may also increase the number of patients suitable for surgical treatment. Despite current treatment options, many patients still experience a recurrence after hepatic resection. More active systemic CTX agents are being used increasingly as adjuvant therapy either before or after surgery. Local tumor ablative therapies, such as microwave coagulation therapy and radiofrequency ablation therapy, should be considered as an adjunct to hepatic resection, in which resection cannot deal with all of the tumor lesions. Formulation of an individualized plan, which combines surgery with systemic CTX, is a necessary task of the multidisciplinary team. The aim of this paper is to discuss different approaches for patients that are treated due to CRC liver metastasis.

Endoscopic radiofrequency ablation has gained interest for treating abdominal tumors. The radiofrequency ablation electrode geometry largely determines the size and shape of the ablation zone. Mismatch between the ablation zone and tumor shapes leads to reoccurrence of the cancer. Recently, work has been published regarding a novel deployable multi-tine electrode for endoscopic radiofrequency ablation. The prior work developed a thermal ablation model to predict the ablation zone surrounding an electrode and a systematic optimization of the electrode shape to treat a specific tumor shape. The purpose of this work is to validate the thermal ablation model through experiments in a tissue phantom that changes color at ablation temperatures. The experiments highlight the importance of thermal tissue damage in finite element modeling. Thermal induced changes in tissue properties, if not accounted for in finite element modeling, can lead to significant overprediction of the expected ablation zone surrounding an electrode.

To determine whether radiofrequency (RF) ablation targeting the tumor-collecting system interface has a durable effect in patients with transfusion-dependent kidney tumor-related hematuria, four patients aged 61-71 years were successfully treated with RF ablation, with a mean follow up of 12 months. Baseline creatinine levels varied from 2.0 mg/dL to 3.7 mg/dL. All patients had received red blood cell transfusions in the days and hours before RF ablation. No subsequent surgical or interventional procedures were required for management of hematuria. Gross hematuria resolved in 24-48 hours in all four patients. Two of the patients are alive with stable renal function and two died of causes unrelated to treatment. RF ablation may be an effective therapeutic option for transfusiondependent cancer-related hematuria in patients with renal insufficiency, solitary kidney, or comorbidities, or after failed conventional therapies in patients who are not candidates for surgery. HEMATURIA related to advanced primary or secondary renal malignancy can be a difficult problem, often complicated by renal insufficiency or comorbidities that may increase the risks and side effects of conventional therapies such as surgery or angiographic embolization. Therapeutic transcatheter embolization has been used as an effective minimally invasive option for management of intractable hematuria (1). However, this procedure can be relatively nonselective and carries the risk of contrast material-induced nephropathy and acute renal failure in patients who already have limited renal function or have undergone nephrectomy. Radiofrequency (RF) ablation has been employed in the management of renal neoplasm-related hematuria (2). In selected patients, RF ablation may prove to be a reasonable alternative to less nephron-sparing techniques. A series of four patients with transfusion-dependent tumor-related gross hematuria were treated successfully with RF ablation, with durable clinical effects. After written informed consent was obtained, all procedures were performed with a Radionics Cool-Tip 200-W RF ablation system (Radionics, Burlington, MA) under conscious sedation with midazolam and fentanyl. In three of four cases, RF ablation procedures were performed percutaneously under ultrasound (US) and computed tomography (CT) guidance, with the remaining procedure performed with US guidance alone with postprocedural CT. Relevant patient data are summarized in the Table . Age varied from 61 to 71 years. Baseline creatinine levels varied from 2.0 mg/dL to 3.7 mg/dL (normal values are 0.6-1.3 mg/dL for women and 0.8-1.5 mg/dL for men). All patients had received red blood cell transfusions in the days and hours before RF ablation.

Background-Adrenocortical carcinoma (ACC) is a rare disease without effective chemotherapy treated most appropriately with resection. The aim of this study was to evaluate our experience with liver resection for metastatic ACC. Methods-This study is a retrospective review of patients who underwent liver resection or radiofrequency ablation (RFA) for ACC from 1979 to 2009. Results-A total of 27 patients were identified. Of the 27, 19 underwent liver resection. Of the 19, 10 had a single liver lesion, and 18 of 19 were rendered free of disease in the liver, although only 11 of 19 were rendered completely free of disease because of extrahepatic disease (EHD). Of the 19, 13 had synchronous EHD. Also, 6 of 17 remained disease free in the liver at a median follow-up of 6.2 years (status of 2 of 19 was unknown). Of the 27 patients, 8 underwent RFA, 7 of 8 became free of disease in the liver, and 5 of 7 had EHD. No patients responded to prior chemotherapy. Median overall survival and survival of patients who underwent liver resection or RFA were both 1.9 years (0.2-12 + years); 5-year actuarial survivals were 29% and 29%, respectively. Disease-free interval (DFI) greater than 9 months from primary resection was associated with longer survival (median 4.1 vs 0.9 years; P = .013). Conclusions-This study is a tertiary institution series of liver resection and RFA for ACC. Given the lack of effective systemic treatment options and the safety of resection and ablation, liver resection or RFA may be considered in selected patients with ACC metastatic to the liver especially with a long DFI. Adrenocortical carcinoma (ACC) is a rare malignancy with an annual incidence of 0.5-2 cases per million population and causes approximately 0.2% of all cancer deaths in the United States. The male-to-female ratio is 1:1.5. 3 ACC presents with symptoms of an abdominal mass or of hormonal excess of Cushing's syndrome, virilization, feminization, or Conn's syndrome. The prognosis for ACC is poor with 5-year survival with complete

143 at medium volume (n = 4) & 118 at low volume centres (n = 15). There was no difference in entry criteria or demographics between groups. CR-D & CR-IM at 12 months are no different between the groups (CR-D 86-90%, CR-IM 74-81%). IM recurrence is significantly lower in high volume centres (16.1% vs 20.3% and 19.2%, Log Rank p < 0.001) but dysplasia recurrence is no different (Log Rank p = 0.12). Rescue EMR was performed less frequently in medium volume centres (0% vs high 5.3% and low volume 10%, p = 001). Conclusion Endotherapy for Barrett's dysplasia is highly effective whatever the centre volume. The rescue EMR rate in medium volume centres is unexplained. Despite lower IM recurrence in high volume centres, dysplasia recurrence rates are not significantly different. Caseload volume of a centre in the UK Registry does not appear to affect outcome.

Background: Radiofrequency (RF)-assisted liver resection allows non-anatomical liver resection with reduced blood loss and offers the opportunity for a combination of resection and ablation. However, there are still concerns with regard to postoperative complications related to this technique. In the present study, we discuss the technical aspects of RF-assisted liver resections and analyse the rate of perioperative complications, focusing on post-hepatectomy liver failure (PLF), bile leak and abscess, and mortality. Methods: Between 2001 and 2015, 857 consecutive open and laparoscopic elective RF-assisted liver resections for benign and malignant liver tumours were reviewed retrospectively to assess perioperative outcomes. Results: Median intraoperative blood loss was 130 mL, with 9.8% of patients requiring blood transfusion. Intraabdominal collections requiring percutaneous drainage developed in 8.7% of all patients, while bile leak at resection margin developed in 2.8% of the cases. Major liver resection was performed in 34% of patients and the incidence of PLF was 1.5% with one directly related mortality (0.1%). Conclusion: RF-assisted liver resection has evolved into a feasible and safe technique of liver resection with an acceptable incidence of perioperative morbidity and a low incidence of PLF and related mortality.

Resumen.-OBJETIVO: Describir un caso clínico de fístula reno cólica como complicación de ablación por radiofrecuencia de carcinoma de células renales. Se revisa la literatura y se exponen las diferentes actitudes diagnósticas y terapéuticas.

Introduction: one of the minimally invasive methods of treatmenting liver malignancies is Radiofrequency Ablation (RFA) which can be applied to primary or secondary tumors. Nevertheless, the disease recurrence is probable after RFA application partially due to the inadequate capability of temperature monitoring of the target tissue and visualizing the thermal damage. The goal of this work was to study the possibility of real-time temperature monitoring of liver tissue undergoing RFA. For this purpose, variations of brightness in DICOM ultrasonic images were investigated. Materials and Methods: 10pieces of fresh bovine liver underwent RFA in ex vivo experiments. Active and passive needle electrodes were inserted into the tissue and a micro-thermometer was placed between them using ultrasonography guidance to invasively monitor temperature changes. Corresponding to each degree of temperature up to 70 E�C, ultrasonic images were acquired followed by turning the RF generator off and ta...

Radiofrequency ablation (RFA) is a minimally invasive thermal therapy that is under investigation as an alternative to surgery for treating liver tumors. Currently, there is a need to monitor the process of lesion creation to guarantee complete treatment of the diseased tissue. In a previous study, sonoelastography was used to detect and measure RFA lesions during exposed liver experiments in a porcine model in vivo. Manual outlining of these lesions in the sonoelastographic images is challenging due to a lack of boundary definition and artifacts formed by respiratory motion and perfusion. As a result, measuring the lesions becomes a time-consuming process with high variability. This work introduces a semi-automatic segmentation algorithm for sonoelastographic data based on level set methods. This algorithm aims to reduce the variability and processing time involved in manual segmentation while maintaining comparable results. For this purpose, eleven RFA lesions are created in five porcine livers exposed through a midline incision. Three independent observers perform manual and semi-automatic measurements on the in vivo sonoelastographic images. These results are compared to measurements from gross pathology. In addition, we assess the feasibility of performing sonoelastograhic measurements transcutaneously. The procedure previously described is repeated with three more lesions without exposing the liver. Overall, the semi-automatic algorithm outperforms manual segmentation in accuracy, speed, and repeatability. These results suggest that sonoelastography in combination with the segmentation algorithm has the potential to be used as a complementary technique to conventional ultrasound for thermal ablation monitoring and follow-up imaging.

Sonoelastography has been developed as an ultrasound‐based elasticity imaging technique. In this technique, external vibration is induced into the target tissue. In general, tissue stiffness is inversely proportional to the amplitude of tissue vibration. Imaging tissue vibration will provide the elasticity distribution in the target region. This study investigated the feasibility of using real‐time sonoelastography to detect and estimate the volume of thermal lesions in porcine livers in vivo. A total of 32 thermal lesions with volumes ranging from were created using radiofrequency ablation (RFA) or high‐intensity focused ultrasound (HIFU) technique. Lesions were imaged using sonoelastography and coregistered B‐mode ultrasound. Volumes were reconstructed from a sequence of two‐dimensional scans. The comparison of sonoelastographic measurements and pathology findings showed good correlation with respect to the area of the lesions ( for RFA lesions, for HIFU lesions). In addition, goo...

Endothermal heat-induced thrombosis (EHIT) is a known complication of endothermal venous ablation procedures. EHIT can lead to deep vein thrombosis/pulmonary embolism, which cause significant disability and, rarely, death. Other studies have evaluated risk factors for EHIT. There is an accepted grading system for EHIT, but there is no consensus on treatment type, duration, or follow-up. We retrospectively evaluated all cases of EHIT after radiofrequency ablation or endovenous laser ablation at our institution during a 7-year period, focusing on classification, treatment, and outcomes of EHIT. The analysis included all patients aged &gt;18 years who underwent radiofrequency ablation or endovenous laser ablation at our institution, Spectrum Health Hospital Vein Solutions (Grand Rapids, Mich), between January 1, 2008, and December 31, 2014. Electronic medical records were queried retrospectively to identify patients with EHIT during the study interval by International Classification of...

143 at medium volume (n = 4) & 118 at low volume centres (n = 15). There was no difference in entry criteria or demographics between groups. CR-D & CR-IM at 12 months are no different between the groups (CR-D 86-90%, CR-IM 74-81%). IM recurrence is significantly lower in high volume centres (16.1% vs 20.3% and 19.2%, Log Rank p < 0.001) but dysplasia recurrence is no different (Log Rank p = 0.12). Rescue EMR was performed less frequently in medium volume centres (0% vs high 5.3% and low volume 10%, p = 001). Conclusion Endotherapy for Barrett's dysplasia is highly effective whatever the centre volume. The rescue EMR rate in medium volume centres is unexplained. Despite lower IM recurrence in high volume centres, dysplasia recurrence rates are not significantly different. Caseload volume of a centre in the UK Registry does not appear to affect outcome.

OBJECTIVE: Clinical success of atrial fibrillation (AF) ablation depends on persistent block of electrical conduction across the ablation lines. The fate of ablations performed with temperature-controlled bipolar radiofrequency (RF) is unknown. The purpose of this study was to validate the electrophysiological (EP) efficacy of these lesions, recording pulmonary vein isolation (PVI) after open chest ablation, in the human being. Ten consecutive mitral patients (mean age: 53 ± 12 years) with concomitant AF were treated with the Cobra Revolution (Estech, San Ramon, CA, USA) bipolar RF device were enrolled for EP assessment. During surgery, pairs of additional temporary wires were positioned on the right PVs (RPV) and on the roof of the left atrium (RLA), before ablation. Pacing thresholds (PTs) were assessed before, after a single encircling ablation and at chest's closure. EP study was repeated before discharge and at 3 weeks. RLA wires served as control. RESULTS: Baseline PTs were 0.83 ± 0.81 mA (range 0.2-3 mA) from RPV and 1.13 ± 0.78 mA (range 0.3-3 mA) from RLA. PVI was reached in all patients acutely, and was maintained at 1 week. At 3 weeks, the PTs were 14.3 ± 4.3 mA from RPV (range 7-20 mA) and 3.1 ± 1.3 mA (range 1.5-7 mA) from RLA. All patients were discharged in sinus rhythm. CONCLUSIONS: Cobra Revolution temperature-controlled bipolar RF provides complete PVI after a single ablation up to 1 week. This notwithstanding, only 30% of patients were completely isolated (exit block validation) at 3 weeks.