Cardiac ablation

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Kelly Ratheal

2016-01-01

Full Text Available Cardiac ablation is a procedure that uses either radiofrequency or cryothermal energy to destroy cells in the heart to terminate and/or prevent arrhythmias. The indications for cardiac catheter ablation include refractory, symptomatic arrhythmias, with more specific guidelines for atrial fibrillation in particular. The ablation procedure itself involves mapping the arrhythmia and destruction of the aberrant pathway in an effort to permanently prevent the arrhythmia. There are many types of arrhythmias, and they require individualized approaches to ablation based on their innately different electrical pathways. Ablation of arrhythmias, such as Wolff-Parkinson-White syndrome, AV nodal reentrant tachycardia, and atrial-fibrillation, is discussed in this review. Ablation has a high success rate overall and minimal complication rates, leading to improved quality of life in many patients.

Comparison of biatrial and left atrial radiofrequency ablation in patients with heart valves diseases

Directory of Open Access Journals (Sweden)

А. В. Богачев-прокофьев

2015-10-01

Full Text Available We analysed results of left atrial and biatrial anatomic scheme of radiofrequency (RF ablation of the atria in patients with valvular heart. From 2007 to 2011, RF ablation procedure performed 283 patients with atrial fibrillation and heart valve disease. Patients were divided into two groups - group I performed a complete circuit biatrial procedure (procedure maze IV - 131 patients, in group II only ablation of the left atrium -152 patients. Most of the patients had long-term persistent AF. The main problem of early postoperative period is dysfunction of pacemaker complex, which observed in 64.9% and 50.7% patients for group I and II, respectively (p = 0.031. Permanent dysfunction of pacemaker complex required implantation of permanent pacemaker (9.2% and 4.6% of cases for group I and II, respectively, p = 0,023. Predictors of dysfunction of the pacemaker complex were biatrial execution method and duration of AF. Freedom from AF and AT during 36 months after surgery was 80.4% for patients in group I and 78.5% for patients in group II, with no statistically significant difference (log-rank test, p = 0.621. Atrial transport function has not revealed that the active fraction of the right atrium was 29.8% higher than in group II in the early postoperative phase and by 17.9% in the long term, with no difference between groups for the left atrium has been received.

Harmine treatment enhances short-term memory in old rats: Dissociation of cognition and the ability to perform the procedural requirements of maze testing.

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Mennenga, Sarah E; Gerson, Julia E; Dunckley, Travis; Bimonte-Nelson, Heather A

2015-01-01

Harmine is a naturally occurring monoamine oxidase inhibitor that has recently been shown to selectively inhibit the dual-specificity tyrosine-(Y)-phosphorylation-regulated kinase 1A (DYRK1A). We investigated the cognitive effects of 1mg (low) Harmine and 5mg (high) Harmine using the delayed-match-to-sample (DMS) asymmetrical 3-choice water maze task to evaluate spatial working and recent memory, and the Morris water maze task (MM) to test spatial reference memory. Animals were also tested on the visible platform task, a water-escape task with the same motor, motivational, and reinforcement components as the other tasks used to evaluate cognition, but differing in its greater simplicity and that the platform was visible above the surface of the water. A subset of the Harmine-high treated animals showed clear motor impairments on all behavioral tasks, and the visible platform task confirmed a lack of competence to perform the procedural components of water maze testing. After excluding animals from the high dose group that could not perform the procedural components of a swim task, it was revealed that both high- and low-dose treatment with Harmine enhanced performance on the latter portion of DMS testing, but had no effect on MM performance. Thus, this study demonstrates the importance of confirming motor and visual competence when studying animal cognition, and verifies the one-day visible platform task as a reliable measure of ability to perform the procedural components necessary for completion of a swim task. Copyright © 2014. Published by Elsevier Inc.

Chronic prenatal caffeine exposure impairs novel object recognition and radial arm maze behaviors in adult rats.

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Soellner, Deborah E; Grandys, Theresa; Nuñez, Joseph L

2009-12-14

In this report, we demonstrate that chronic prenatal exposure to a moderate dose of caffeine disrupts novel object recognition and radial arm maze behaviors in adult male and female rats. Pregnant dams were administered either tap water or 75 mg/L caffeinated tap water throughout gestation. Oral self-administration in the drinking water led to an approximate maternal intake of 10mg/kg/day, equivalent to 2-3 cups of coffee/day in humans based on a metabolic body weight conversion. In adulthood, the offspring underwent testing on novel object recognition, radial arm maze, and Morris water maze tasks. Prenatal caffeine exposure was found to impair 24-h memory retention in the novel object recognition task and impair both working and reference memory in the radial arm maze. However, prenatal caffeine exposure did not alter Morris water maze performance in either a simple water maze procedure or in an advanced water maze procedure that included reversal and working memory paradigms. These findings demonstrate that chronic oral intake of caffeine throughout gestation can alter adult cognitive behaviors in rats.

X-ray exposure hazards for physicians performing ablation procedures and device implantation

DEFF Research Database (Denmark)

Marinskis, Germanas; Bongiorni, Maria Grazia; Dagres, Nikolaos

2013-01-01

The purpose of the survey was to evaluate physician's and authorities policies and clinical practices when using occupational X-ray during ablation procedures and device implantation. This survey shows infrequent use of lead gloves, radiation absorbing pads, and lead glass cabins, but increasing ...

CT-guided Bipolar and Multipolar Radiofrequency Ablation (RF Ablation) of Renal Cell Carcinoma: Specific Technical Aspects and Clinical Results

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Sommer, C. M., E-mail: christof.sommer@med.uni-heidelberg.de [University Hospital Heidelberg, INF 110, Department of Diagnostic and Interventional Radiology (Germany); Lemm, G.; Hohenstein, E. [Minimally Invasive Therapies and Nuclear Medicine, SLK Kliniken Heilbronn GmbH, Clinic for Radiology (Germany); Bellemann, N.; Stampfl, U. [University Hospital Heidelberg, INF 110, Department of Diagnostic and Interventional Radiology (Germany); Goezen, A. S.; Rassweiler, J. [Clinic for Urology, SLK Kliniken Heilbronn GmbH (Germany); Kauczor, H. U.; Radeleff, B. A. [University Hospital Heidelberg, INF 110, Department of Diagnostic and Interventional Radiology (Germany); Pereira, P. L. [Minimally Invasive Therapies and Nuclear Medicine, SLK Kliniken Heilbronn GmbH, Clinic for Radiology (Germany)

2013-06-15

Purpose. This study was designed to evaluate the clinical efficacy of CT-guided bipolar and multipolar radiofrequency ablation (RF ablation) of renal cell carcinoma (RCC) and to analyze specific technical aspects between both technologies. Methods. We included 22 consecutive patients (3 women; age 74.2 {+-} 8.6 years) after 28 CT-guided bipolar or multipolar RF ablations of 28 RCCs (diameter 2.5 {+-} 0.8 cm). Procedures were performed with a commercially available RF system (Celon AG Olympus, Berlin, Germany). Technical aspects of RF ablation procedures (ablation mode [bipolar or multipolar], number of applicators and ablation cycles, overall ablation time and deployed energy, and technical success rate) were analyzed. Clinical results (local recurrence-free survival and local tumor control rate, renal function [glomerular filtration rate (GFR)]) and complication rates were evaluated. Results. Bipolar RF ablation was performed in 12 procedures and multipolar RF ablation in 16 procedures (2 applicators in 14 procedures and 3 applicators in 2 procedures). One ablation cycle was performed in 15 procedures and two ablation cycles in 13 procedures. Overall ablation time and deployed energy were 35.0 {+-} 13.6 min and 43.7 {+-} 17.9 kJ. Technical success rate was 100 %. Major and minor complication rates were 4 and 14 %. At an imaging follow-up of 15.2 {+-} 8.8 months, local recurrence-free survival was 14.4 {+-} 8.8 months and local tumor control rate was 93 %. GFR did not deteriorate after RF ablation (50.8 {+-} 16.6 ml/min/1.73 m{sup 2} before RF ablation vs. 47.2 {+-} 11.9 ml/min/1.73 m{sup 2} after RF ablation; not significant). Conclusions. CT-guided bipolar and multipolar RF ablation of RCC has a high rate of clinical success and low complication rates. At short-term follow-up, clinical efficacy is high without deterioration of the renal function.

CT-Guided Microwave Ablation of 45 Renal Tumors: Analysis of Procedure Complexity Utilizing a Percutaneous Renal Ablation Complexity Scoring System.

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Mansilla, Alberto V; Bivins, Eugene E; Contreras, Francisco; Hernandez, Manuel A; Kohler, Nathan; Pepe, Julie W

2017-02-01

To develop a scoring system that stratifies complexity of percutaneous ablation of renal tumors. Analysis was performed of 36 consecutive patients (mean age, 64 y; range, 30-89 y) who underwent CT-guided microwave (MW) ablation of 45 renal tumors (mean tumor diameter, 2.4 cm; range, 1.2-4.0 cm). Technical success and effectiveness were determined based on intraprocedural and follow-up imaging studies. The RENAL score and the proposed percutaneous renal ablation complexity (P-RAC) score were calculated for each tumor. Technical success was 93.3% (n = 42). Biopsy of 38 of 45 renal tumors revealed 23 renal cell carcinomas. Median follow-up period was 9.7 months (range, 2.9-46.8 months). There were no tumor recurrences. One major complication, ureteropelvic junction stricture, occurred (2.6%). The P-RAC score was found to differ statistically from the RENAL score (t = 3.754, df = 44, P = .001). A positive correlation was found between the P-RAC score and number of antenna insertions (r = .378, n = 45, P = .011) and procedure duration (r = .328, n = 45, P = .028). No correlation was found between the RENAL score and number of MW antenna insertions (r = .110, n = 45, P = .472) or procedure duration (r = .263, n = 45, P = .081). Hydrodissection was significantly more common in the P-RAC high-complexity category than in low-complexity category (χ 2 = 12.073, df = 2, P = .002). The P-RAC score may be useful in stratifying percutaneous renal ablation complexity. Further studies with larger sample sizes are necessary to validate the P-RAC score and to determine if it can predict risk of complications. Copyright © 2016 SIR. Published by Elsevier Inc. All rights reserved.

Early Heparin Administration Reduces Risk for Left Atrial Thrombus Formation during Atrial Fibrillation Ablation Procedures

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Stefan Asbach

2011-01-01

Full Text Available Objective. Despite the use of anticoagulation during left atrial (LA ablation procedures, ischemic cerebrovascular accidents (CVAs are recognized as a serious complication. Heparin is usually given after safe transseptal access has been obtained, resulting in a short unprotected dwell time of catheters within the LA, which may account for CVAs. We investigated the frequency of CVAs and LA thrombus formation as detected by intracardiac ultrasound (ICE depending on the timing of heparin administration. Methods and Results. Sixty LA ablation procedures with the use of ICE were performed in 55 patients. Patients were grouped by heparin administration after (Group I, =13 and before (Group II, =47 transseptal access. Group I patients were younger (56.6±13.7 versus 65.9±9.9 years, =.01; other clinical and echocardiographic characteristics did not differ between groups. Early thrombus formation was observed in 2 (15.4% of group I patients as compared to 0% of group II patients (=.04. One CVA (2.1% occurred in one group II patient without prior thrombus detection, and none occurred in group I patients (=ns. Conclusion. Early administration of heparin reduces the risk of early intracardiac thrombus formation during LA ablation procedures. This did not result in reduced rate of CVAs.

CT-guided Bipolar and Multipolar Radiofrequency Ablation (RF Ablation) of Renal Cell Carcinoma: Specific Technical Aspects and Clinical Results

International Nuclear Information System (INIS)

Sommer, C. M.; Lemm, G.; Hohenstein, E.; Bellemann, N.; Stampfl, U.; Goezen, A. S.; Rassweiler, J.; Kauczor, H. U.; Radeleff, B. A.; Pereira, P. L.

2013-01-01

Purpose. This study was designed to evaluate the clinical efficacy of CT-guided bipolar and multipolar radiofrequency ablation (RF ablation) of renal cell carcinoma (RCC) and to analyze specific technical aspects between both technologies. Methods. We included 22 consecutive patients (3 women; age 74.2 ± 8.6 years) after 28 CT-guided bipolar or multipolar RF ablations of 28 RCCs (diameter 2.5 ± 0.8 cm). Procedures were performed with a commercially available RF system (Celon AG Olympus, Berlin, Germany). Technical aspects of RF ablation procedures (ablation mode [bipolar or multipolar], number of applicators and ablation cycles, overall ablation time and deployed energy, and technical success rate) were analyzed. Clinical results (local recurrence-free survival and local tumor control rate, renal function [glomerular filtration rate (GFR)]) and complication rates were evaluated. Results. Bipolar RF ablation was performed in 12 procedures and multipolar RF ablation in 16 procedures (2 applicators in 14 procedures and 3 applicators in 2 procedures). One ablation cycle was performed in 15 procedures and two ablation cycles in 13 procedures. Overall ablation time and deployed energy were 35.0 ± 13.6 min and 43.7 ± 17.9 kJ. Technical success rate was 100 %. Major and minor complication rates were 4 and 14 %. At an imaging follow-up of 15.2 ± 8.8 months, local recurrence-free survival was 14.4 ± 8.8 months and local tumor control rate was 93 %. GFR did not deteriorate after RF ablation (50.8 ± 16.6 ml/min/1.73 m 2 before RF ablation vs. 47.2 ± 11.9 ml/min/1.73 m 2 after RF ablation; not significant). Conclusions. CT-guided bipolar and multipolar RF ablation of RCC has a high rate of clinical success and low complication rates. At short-term follow-up, clinical efficacy is high without deterioration of the renal function.

Radiofrequency ablation of chondroblastoma: procedure technique, clinical and MR imaging follow up of four cases

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Christie-Large, M.; Evans, N.; Davies, A.M.; James, S.L.J. [Royal Orthopaedic Hospital Foundation Trust, Department of Radiology, Birmingham (United Kingdom)

2008-11-15

The aim of this study is to describe the procedure technique, clinical and imaging outcomes of patients treated with radiofrequency ablation for chondroblastoma. Four patients (female/male, 3:1; mean age, 13 years; age range; 9-16 years) underwent the procedure. All had pre-operative magnetic resonance imaging (MRI) and symptomatic, biopsy-proven chondroblastomas (two proximal femur, two proximal tibia). The lesion size ranged from 1.5 to 2.5 cm in maximal dimension (mean size, 1.8 cm). Bone access was gained with a Bonopty biopsy needle system (mean number of radiofrequency needle placements, 5; mean ablation time, 31 min). Clinical and MRI follow-up was available in all cases (mean, 12.25 months; range, 5-18 months). All patients reported resolution of symptoms at 2-6 weeks post ablation. At their most recent clinical follow-up, three patients remained completely asymptomatic with full return to normal activities and one patient had minor local discomfort (different pain pattern) that was not limiting activity. All four patients' follow-up MRI studies demonstrated resolution of the oedema pattern around the lesion and temporal evolution of the internal signal characteristics with fatty replacement. Radiofrequency ablation for chondroblastoma provides an alternative to surgical curettage, and we have demonstrated both a clinical improvement in symptoms and the follow-up MRI appearances. (orig.)

Automatic segmentation of rotational x-ray images for anatomic intra-procedural surface generation in atrial fibrillation ablation procedures.

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Manzke, Robert; Meyer, Carsten; Ecabert, Olivier; Peters, Jochen; Noordhoek, Niels J; Thiagalingam, Aravinda; Reddy, Vivek Y; Chan, Raymond C; Weese, Jürgen

2010-02-01

Since the introduction of 3-D rotational X-ray imaging, protocols for 3-D rotational coronary artery imaging have become widely available in routine clinical practice. Intra-procedural cardiac imaging in a computed tomography (CT)-like fashion has been particularly compelling due to the reduction of clinical overhead and ability to characterize anatomy at the time of intervention. We previously introduced a clinically feasible approach for imaging the left atrium and pulmonary veins (LAPVs) with short contrast bolus injections and scan times of approximately 4 -10 s. The resulting data have sufficient image quality for intra-procedural use during electro-anatomic mapping (EAM) and interventional guidance in atrial fibrillation (AF) ablation procedures. In this paper, we present a novel technique to intra-procedural surface generation which integrates fully-automated segmentation of the LAPVs for guidance in AF ablation interventions. Contrast-enhanced rotational X-ray angiography (3-D RA) acquisitions in combination with filtered-back-projection-based reconstruction allows for volumetric interrogation of LAPV anatomy in near-real-time. An automatic model-based segmentation algorithm allows for fast and accurate LAPV mesh generation despite the challenges posed by image quality; relative to pre-procedural cardiac CT/MR, 3-D RA images suffer from more artifacts and reduced signal-to-noise. We validate our integrated method by comparing 1) automatic and manual segmentations of intra-procedural 3-D RA data, 2) automatic segmentations of intra-procedural 3-D RA and pre-procedural CT/MR data, and 3) intra-procedural EAM point cloud data with automatic segmentations of 3-D RA and CT/MR data. Our validation results for automatically segmented intra-procedural 3-D RA data show average segmentation errors of 1) approximately 1.3 mm compared with manual 3-D RA segmentations 2) approximately 2.3 mm compared with automatic segmentation of pre-procedural CT/MR data and 3

A New Radiofrequency Ablation Procedure to Treat Sacroiliac Joint Pain.

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Cheng, Jianguo; Chen, See Loong; Zimmerman, Nicole; Dalton, Jarrod E; LaSalle, Garret; Rosenquist, Richard

2016-01-01

Low back pain may arise from disorders of the sacroiliac joint in up to 30% of patients. Radiofrequency ablation (RFA) of the nerves innervating the sacroiliac joint has been shown to be a safe and efficacious strategy. We aimed to develop a new RFA technique to relieve low back pain secondary to sacroiliac joint disorders. Methodology development with validation through prospective observational non-randomized trial (PONRT). Academic multidisciplinary health care system, Ohio, USA. We devised a guide-block to facilitate accurate placement of multiple electrodes to simultaneously ablate the L5 dorsal ramus and lateral branches of the S1, S2, and S3 dorsal rami. This was achieved by bipolar radiofrequency ablation (b-RFA) to create a strip lesion from the lateral border of the base of the sacral superior articular process (L5-S1 facet joint) to the lateral border of the S3 sacral foramen. We applied this technique in 31 consecutive patients and compared the operating time, x-ray exposure time and dose, and clinical outcomes with patients (n = 62) who have been treated with the cooled radiofrequency technique. Patients' level of pain relief was reported as 80% pain relief at one, 3, 6, and 12 months after the procedure. The relationship between RFA technique and duration of pain relief was evaluated using interval-censored multivariable Cox regression. The new technique allowed reduction of operating time by more than 50%, x-ray exposure time and dose by more than 80%, and cost by more than $1,000 per case. The percent of patients who achieved > 50% pain reduction was significantly higher in the b-RFA group at 3, 6, and 12 months follow-up, compared to the cooled radiofrequency group. No complications were observed in either group. Although the major confounding factors were taken into account in the analysis, use of historical controls does not balance observed and unobserved potential confounding variables between groups so that the reported results are potentially

Analysis of excimer laser radiant exposure effect toward corneal ablation volume at LASIK procedure

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Adiati, Rima Fitria; Rini Rizki, Artha Bona; Kusumawardhani, Apriani; Setijono, Heru; Rahmadiansah, Andi

2016-11-01

LASIK (Laser Asissted In Situ Interlamelar Keratomilieusis) is a technique for correcting refractive disorders of the eye such as myopia and astigmatism using an excimer laser. This procedure use photoablation technique to decompose corneal tissues. Although preferred due to its efficiency, permanency, and accuracy, the inappropriate amount radiant exposure often cause side effects like under-over correction, irregular astigmatism and problems on surrounding tissues. In this study, the radiant exposure effect toward corneal ablation volume has been modelled through several processes. Data collecting results is laser data specifications with 193 nm wavelength, beam diameter of 0.065 - 0.65 cm, and fluence of 160 mJ/cm2. For the medical data, the myopia-astigmatism value, cornea size, corneal ablation thickness, and flap data are taken. The first modelling step is determining the laser diameter between 0.065 - 0.65 cm with 0.45 cm increment. The energy, power, and intensity of laser determined from laser beam area. Number of pulse and total energy is calculated before the radiant exposure of laser is obtained. Next is to determine the parameters influence the ablation volume. Regression method used to create the equation, and then the spot size is substituted to the model. The validation used is statistic correlation method to both experimental data and theory. By the model created, it is expected that any potential complications can be prevented during LASIK procedures. The recommendations can give the users clearer picture to determine the appropriate amount of radiant exposure with the corneal ablation volume necessary.

A computer vision-based automated Figure-8 maze for working memory test in rodents.

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Pedigo, Samuel F; Song, Eun Young; Jung, Min Whan; Kim, Jeansok J

2006-09-30

The benchmark test for prefrontal cortex (PFC)-mediated working memory in rodents is a delayed alternation task utilizing variations of T-maze or Figure-8 maze, which requires the animals to make specific arm entry responses for reward. In this task, however, manual procedures involved in shaping target behavior, imposing delays between trials and delivering rewards can potentially influence the animal's performance on the maze. Here, we report an automated Figure-8 maze which does not necessitate experimenter-subject interaction during shaping, training or testing. This system incorporates a computer vision system for tracking, motorized gates to impose delays, and automated reward delivery. The maze is controlled by custom software that records the animal's location and activates the gates according to the animal's behavior and a control algorithm. The program performs calculations of task accuracy, tracks movement sequence through the maze, and provides other dependent variables (such as running speed, time spent in different maze locations, activity level during delay). Testing in rats indicates that the performance accuracy is inversely proportional to the delay interval, decreases with PFC lesions, and that animals anticipate timing during long delays. Thus, our automated Figure-8 maze is effective at assessing working memory and provides novel behavioral measures in rodents.

Luminal esophageal temperature monitoring with a deflectable esophageal temperature probe and intracardiac echocardiography may reduce esophageal injury during atrial fibrillation ablation procedures: results of a pilot study.

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Leite, Luiz R; Santos, Simone N; Maia, Henrique; Henz, Benhur D; Giuseppin, Fábio; Oliverira, Anderson; Zanatta, André R; Peres, Ayrton K; Novakoski, Clarissa; Barreto, Jose R; Vassalo, Fabrício; d'Avila, Andre; Singh, Sheldon M

2011-04-01

Luminal esophageal temperature (LET) monitoring is one strategy to minimize esophageal injury during atrial fibrillation ablation procedures. However, esophageal ulceration and fistulas have been reported despite adequate LET monitoring. The objective of this study was to assess a novel approach to LET monitoring with a deflectable LET probe on the rate of esophageal injury in patients undergoing atrial fibrillation ablation. Forty-five consecutive patients undergoing an atrial fibrillation ablation procedure followed by esophageal endoscopy were included in this prospective observational pilot study. LET monitoring was performed with a 7F deflectable ablation catheter that was positioned as close as possible to the site of left atrial ablation using the deflectable component of the catheter guided by visualization of its position on intracardiac echocardiography. Ablation in the posterior left atrial was limited to 25 W and terminated when the LET increased 2°C from baseline. Endoscopy was performed 1 to 2 days after the procedure. All patients had at least 1 LET elevation >2°C necessitating cessation of ablation. Deflection of the LET probe was needed to accurately measure LET in 5% of patients when ablating near the left pulmonary veins, whereas deflection of the LET probe was necessary in 88% of patients when ablating near the right pulmonary veins. The average maximum increase in LET was 2.5±1.5°C. No patients had esophageal thermal injury on follow-up endoscopy. A strategy of optimal LET probe placement using a deflectable LET probe and intracardiac echocardiography guidance, combined with cessation of radiofrequency ablation with a 2°C rise in LET, may reduce esophageal thermal injury during left atrial ablation procedures.

Comparing energy sources for surgical ablation of atrial fibrillation: a Bayesian network meta-analysis of randomized, controlled trials.

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Phan, Kevin; Xie, Ashleigh; Kumar, Narendra; Wong, Sophia; Medi, Caroline; La Meir, Mark; Yan, Tristan D

2015-08-01

Simplified maze procedures involving radiofrequency, cryoenergy and microwave energy sources have been increasingly utilized for surgical treatment of atrial fibrillation as an alternative to the traditional cut-and-sew approach. In the absence of direct comparisons, a Bayesian network meta-analysis is another alternative to assess the relative effect of different treatments, using indirect evidence. A Bayesian meta-analysis of indirect evidence was performed using 16 published randomized trials identified from 6 databases. Rank probability analysis was used to rank each intervention in terms of their probability of having the best outcome. Sinus rhythm prevalence beyond the 12-month follow-up was similar between the cut-and-sew, microwave and radiofrequency approaches, which were all ranked better than cryoablation (respectively, 39, 36, and 25 vs 1%). The cut-and-sew maze was ranked worst in terms of mortality outcomes compared with microwave, radiofrequency and cryoenergy (2 vs 19, 34, and 24%, respectively). The cut-and-sew maze procedure was associated with significantly lower stroke rates compared with microwave ablation [odds ratio <0.01; 95% confidence interval 0.00, 0.82], and ranked the best in terms of pacemaker requirements compared with microwave, radiofrequency and cryoenergy (81 vs 14, and 1, <0.01% respectively). Bayesian rank probability analysis shows that the cut-and-sew approach is associated with the best outcomes in terms of sinus rhythm prevalence and stroke outcomes, and remains the gold standard approach for AF treatment. Given the limitations of indirect comparison analysis, these results should be viewed with caution and not over-interpreted. © The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Electric Current Solves Mazes

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Ayrinhac, Simon

2014-01-01

We present in this work a demonstration of the maze-solving problem with electricity. Electric current flowing in a maze as a printed circuit produces Joule heating and the right way is instantaneously revealed with infrared thermal imaging. The basic properties of electric current can be discussed in this context, with this challenging question:…

Impact of catheter ablation with remote magnetic navigation on procedural outcomes in patients with persistent and long-standing persistent atrial fibrillation

DEFF Research Database (Denmark)

Jin, Qi; Pehrson, Steen; Jacobsen, Peter Karl

2015-01-01

with RMN. METHODS: A total of 313 patients (275 male, age 59 ± 9.5 years) with PsAF (187/313) or L-PsAF (126/313) undergoing ablation using RMN were included. Patients' disease history, pulmonary venous anatomy, left atrial (LA) volume, procedure time, mapping plus ablation time, radiofrequency (RF...

Low rate of asymptomatic cerebral embolism and improved procedural efficiency with the novel pulmonary vein ablation catheter GOLD: results of the PRECISION GOLD trial.

Science.gov (United States)

De Greef, Yves; Dekker, Lukas; Boersma, Lucas; Murray, Stephen; Wieczorek, Marcus; Spitzer, Stefan G; Davidson, Neil; Furniss, Steve; Hocini, Mélèze; Geller, J Christoph; Csanádi, Zoltan

2016-05-01

This prospective, multicentre study (PRECISION GOLD) evaluated the incidence of asymptomatic cerebral embolism (ACE) after pulmonary vein isolation (PVI) using a new gold multi-electrode radiofrequency (RF) ablation catheter, pulmonary vein ablation catheter (PVAC) GOLD. Also, procedural efficiency of PVAC GOLD was compared with ERACE. The ERACE study demonstrated that a low incidence of ACE can be achieved with a platinum multi-electrode RF catheter (PVAC) combined with procedural manoeuvres to reduce emboli. A total of 51 patients with paroxysmal atrial fibrillation (AF) (age 57 ± 9 years, CHA2DS2-VASc score 1.4 ± 1.4) underwent AF ablation with PVAC GOLD. Continuous oral anticoagulation using vitamin K antagonists, submerged catheter introduction, and heparinization (ACT ≥ 350 s prior to ablation) were applied. Cerebral magnetic resonance imaging (MRI) scans were performed within 48 h before and 16-72 h post-ablation. Cognitive function assessed by the Mini-Mental State Exam at baseline and 30 days post-ablation. New post-procedural ACE occurred in only 1 of 48 patients (2.1%) and was not detectable on MRI after 30 days. The average number of RF applications per patient to achieve PVI was lower in PRECISION GOLD (20.3 ± 10.0) than in ERACE (28.8 ± 16.1; P = 0.001). Further, PVAC GOLD ablations resulted in significantly fewer low-power (GOLD in combination with established embolic lowering manoeuvres results in a low incidence of ACE. Pulmonary vein ablation catheter GOLD demonstrates improved biophysical efficiency compared with platinum PVAC. ClinicalTrials.gov NCT01767558. © The Author 2016. Published by Oxford University Press on behalf of the European Society of Cardiology.

Voltage and pace-capture mapping of linear ablation lesions overestimates chronic ablation gap size.

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O'Neill, Louisa; Harrison, James; Chubb, Henry; Whitaker, John; Mukherjee, Rahul K; Bloch, Lars Ølgaard; Andersen, Niels Peter; Dam, Høgni; Jensen, Henrik K; Niederer, Steven; Wright, Matthew; O'Neill, Mark; Williams, Steven E

2018-04-26

Conducting gaps in lesion sets are a major reason for failure of ablation procedures. Voltage mapping and pace-capture have been proposed for intra-procedural identification of gaps. We aimed to compare gap size measured acutely and chronically post-ablation to macroscopic gap size in a porcine model. Intercaval linear ablation was performed in eight Göttingen minipigs with a deliberate gap of ∼5 mm left in the ablation line. Gap size was measured by interpolating ablation contact force values between ablation tags and thresholding at a low force cut-off of 5 g. Bipolar voltage mapping and pace-capture mapping along the length of the line were performed immediately, and at 2 months, post-ablation. Animals were euthanized and gap sizes were measured macroscopically. Voltage thresholds to define scar were determined by receiver operating characteristic analysis as voltage, pace-capture, and ablation contact force maps. All modalities overestimated chronic gap size, by 1.4 ± 2.0 mm (ablation contact force map), 5.1 ± 3.4 mm (pace-capture), and 9.5 ± 3.8 mm (voltage mapping). Error on ablation contact force map gap measurements were significantly less than for voltage mapping (P = 0.003, Tukey's multiple comparisons test). Chronically, voltage mapping and pace-capture mapping overestimated macroscopic gap size by 11.9 ± 3.7 and 9.8 ± 3.5 mm, respectively. Bipolar voltage and pace-capture mapping overestimate the size of chronic gap formation in linear ablation lesions. The most accurate estimation of chronic gap size was achieved by analysis of catheter-myocardium contact force during ablation.

Cryoballoon Catheter Ablation in Atrial Fibrillation

Directory of Open Access Journals (Sweden)

Cevher Ozcan

2011-01-01

Full Text Available Pulmonary vein isolation with catheter ablation is an effective treatment in patients with symptomatic atrial fibrillation refractory or intolerant to antiarrhythmic medications. The cryoballoon catheter was recently approved for this procedure. In this paper, the basics of cryothermal energy ablation are reviewed including its ability of creating homogenous lesion formation, minimal destruction to surrounding vasculature, preserved tissue integrity, and lower risk of thrombus formation. Also summarized here are the publications describing the clinical experience with the cryoballoon catheter ablation in both paroxysmal and persistent atrial fibrillation, its safety and efficacy, and discussions on the technical aspect of the cryoballoon ablation procedure.

Rolling block mazes are PSPACE-complete

NARCIS (Netherlands)

Buchin, K.; Buchin, M.

2012-01-01

In a rolling block maze, one or more blocks lie on a rectangular board with square cells. In most mazes, the blocks have size k × m × n where k, m, n are integers that determine the size of the block in terms of units of the size of the board cells. The task of a rolling block maze is to roll a

Multiphasic helical Computed Tomography of hepatocellular carcinoma. Evaluation after various percutaneous ablation procedures

International Nuclear Information System (INIS)

Catalano, O.; Esposito, M.; Lobianco, R.; Cusati, B.; Altei, F.; Siani, A.

1999-01-01

The purpose of this paper is to report the personal experience with helical CT evaluation of hepatocellular carcinoma treated with various percutaneous interventional procedures. From December 1996 to September 1998 it were examined with helical CT 41 patients (73 nodules in all) with hepatocellular carcinoma treated with percutaneous ablation therapies: conventional ethanol injection in 18 subjects (31 nodules), one-shot ethanol injection 3 (8 nodules), radiofrequency thermal ablation in 16 (25 nodules), and combined chemo embolization and ethanol injection in 4 (9 nodules). CT performed was 4-27 days after the last session, acquiring biphasic volumetric images in 14 patients and triphasic volumetric images in 27. A second treatment with subsequent CT study was performed for 28 lesions; 15 underwent 3 serial studies and 6 underwent 4 studies. Compared with pretreatment findings, the diameter was unchanged in 62% of the nodules and increased in 38%. Morphology was unchanged in 63% of the lesions while in 37% a mild deformation toward the needle path or a more regular and round shape was evident. Borders were unchanged in 37% of the cases and modified in 63%, appearing well-defined in 73% and ill-defined in 27%. The necrotic portion had a low attenuation with a nodule-to-parenchyma gradient more evident on delayed than on venous and finally arterial acquisitions; 8% of the lesions were not recognizable on unenhanced scans. During the arterial phase the residual tumor appeared hyperdense in 97% of the nodules and isodense in 3%, while during the portal phase it was hyperdense in 22%, isodense in 28% and hypodense in 50%, and during the delayed phase hypodense in 100%. Residual viable tissue was identified in 44% of the nodules and quantified as 100% in 1% of all lesions, > 75% in 3%, > 50% in 4%, > 25% in 23%. In conclusion, multiple-phase helical CT allows optimal depiction of primitive liver nodules treated with percutaneous interventional procedures and has a

Percutaneous Renal Tumor Ablation: Radiation Exposure During Cryoablation and Radiofrequency Ablation

Energy Technology Data Exchange (ETDEWEB)

McEachen, James C., E-mail: james.mceachen2@gmail.com [Mayo Clinic, Division of Preventive, Occupational, and Aerospace Medicine (United States); Leng, Shuai; Atwell, Thomas D. [Mayo Clinic, Department of Radiology (United States); Tollefson, Matthew K. [Mayo Clinic, Department of Urology (United States); Friese, Jeremy L. [Mayo Clinic, Department of Radiology (United States); Wang, Zhen; Murad, M. Hassan [Mayo Clinic, Division of Preventive, Occupational, and Aerospace Medicine (United States); Schmit, Grant D. [Mayo Clinic, Department of Radiology (United States)

2016-02-15

IntroductionOnce reserved solely for non-surgical cases, percutaneous ablation is becoming an increasingly popular treatment option for a wider array of patients with small renal masses and the radiation risk needs to be better defined as this transition continues.Materials and MethodsRetrospective review of our renal tumor ablation database revealed 425 patients who underwent percutaneous ablation for treatment of 455 renal tumors over a 5-year time period. Imparted radiation dose information was reviewed for each procedure and converted to effective patient dose and skin dose using established techniques. Statistical analysis was performed with each ablative technique.ResultsFor the 331 cryoablation procedures, the mean DLP was 6987 mGycm (SD = 2861) resulting in a mean effective dose of 104.7 mSv (SD = 43.5) and the mean CTDI{sub vol} was 558 mGy (SD = 439) resulting in a mean skin dose of 563.2 mGy (SD = 344.1). For the 124 RFA procedures, the mean DLP was 3485 mGycm (SD = 1630) resulting in a mean effective dose of 50.3 mSv (SD = 24.0) and the mean CTDI{sub vol} was 232 mGy (SD = 149) resulting in a mean skin dose of 233.2 mGy (SD = 117.4). The difference in patient radiation exposure between the two renal ablation techniques was statistically significant (p < 0.001).ConclusionBoth cryoablation and RFA imparted an average skin dose that was well below the 2 Gy deterministic threshold for appreciable sequela. Renal tumor cryoablation resulted in a mean skin and effective radiation dose more than twice that for RFA. The radiation exposure for both renal tumor ablation techniques was at the high end of the medical imaging radiation dose spectrum.

Glow discharge based device for solving mazes

Energy Technology Data Exchange (ETDEWEB)

Dubinov, Alexander E., E-mail: dubinov-ae@yandex.ru; Mironenko, Maxim S.; Selemir, Victor D. [Russian Federal Nuclear Center − All-Russian Scientific and Research Institute of Experimental Physics (RFNC-VNIIEF), Sarov, Nizhni Novgorod region 607188 (Russian Federation); Sarov Institute of Physics and Technology (SarFTI) of National Research Nuclear University “MEPhI,” Sarov, Nizhni Novgorod region 607188 (Russian Federation); Maksimov, Artem N.; Pylayev, Nikolay A. [Russian Federal Nuclear Center − All-Russian Scientific and Research Institute of Experimental Physics (RFNC-VNIIEF), Sarov, Nizhni Novgorod region 607188 (Russian Federation)

2014-09-15

A glow discharge based device for solving mazes has been designed and tested. The device consists of a gas discharge chamber and maze-transformer of radial-azimuth type. It allows changing of the maze pattern in a short period of time (within several minutes). The device has been tested with low pressure air. Once switched on, a glow discharge has been shown to find the shortest way through the maze from the very first attempt, even if there is a section with potential barrier for electrons on the way. It has been found that ionization waves (striations) can be excited in the maze along the length of the plasma channel. The dependancy of discharge voltage on the length of the optimal path through the maze has been measured. A reduction in discharge voltage with one or two potential barriers present has been found and explained. The dependency of the magnitude of discharge ignition voltage on the length of the optimal path through the maze has been measured. The reduction of the ignition voltage with the presence of one or two potential barriers has been observed and explained.

Pheochromocytoma diagnosed after anticoagulation for atrial fibrillation ablation procedure: a giant in disguise.

Science.gov (United States)

Galvão Braga, Carlos; Ribeiro, Sílvia; Martins, Juliana; Arantes, Carina; Ramos, Vítor; Primo, João; Magalhães, Sónia; Correia, Adelino

2014-04-01

Pheochromocytoma is a rare catecholamine-producing tumor, discovered incidentally in 50% of cases. We present the case of a 44-year-old male with a history of paroxysmal palpitations. Baseline ECG, transthoracic echocardiogram and ECG stress test showed no relevant alterations. Paroxysmal atrial fibrillation was detected on 24-hour Holter ECG. After antiarrhythmic therapy, the patient remained symptomatic, and was accordingly referred for electrophysiological study and atrial fibrillation ablation. Anticoagulation was initiated before the procedure. After ablation and still anticoagulated, he complained of hematospermia. The abdominal and pelvic imaging study showed a 10-cm left adrenal mass, predominantly cystic, compatible with pheochromocytoma, which was confirmed after biochemical tests (increased urine metanephrines and plasma catecholamines). Metaiodobenzylguanidine scintigraphy scanning confirmed localized disease in the adrenal gland, excluding other uptake foci. Following appropriate preoperative management, surgical resection of the giant mass was performed successfully and without complications. Copyright © 2013 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.

INTRAOPERATIVE RADIOFREQUENCY AND CRYOABLATION FOR ATRIAL FIBRILLATION IN PATIENTS WITH VALVULAR HEART DISEASE

Directory of Open Access Journals (Sweden)

N. Maghamipour N. Safaie

2007-05-01

Full Text Available Patients with valvular heart disease and suffering atrial fibrillation of more than 12 months duration have a low probability of remaining in sinus rhythm after valve surgery alone. We performed intra-operative radiofrequency ablation or cryoablation as an alternative to surgical maze ІІІ procedure to create linear lesion lines for conversion of this arrhythmia to sinus rhythm. A total of 30 patients with valvular heart disease and chronic persistent atrial fibrillation underwent different combinations of valve surgery and concomitant maze procedure with radiofrequency or cryo probes. These patients aged 48.10 ± 9.84 years in radiofrequency ablation group and 51.10 ± 13.93 years in cryoablation group. Both atrial ablation with radiofrequency probes, needed 26.15 ± 3.67 min extra ischemic time and ablation by mean of cryo-probes needed an extra ischemic time of 29.62 ± 4.27 min. There was one in hospital death postoperatively because of respiratory failure but no other complication. 6 months after the operation, among 30 patients with both atrial ablations, 25 patients were in sinus rhythm, no patient had junctional rhythm and 5 patients had persistent atrial fibrillation. At 12 months follow up, freedom from atrial fibrillation was 85% in radiofrequency group and 80% in cryo group. Doppler echocardiography in these patients demonstrated atrial contractility in 70% of the patients. Intraoperative radiofrequency or cryo-ablation of both atriums are effective and less invasive alternatives for the original maze procedure to eliminate the atrial fibrillation, and can be done in patients with valvular heart disease without increasing the risk of operation.

Ablation of an atriofascicular accessory pathway with a zero-fluoroscopy procedure

Directory of Open Access Journals (Sweden)

Riccardo Proietti, MD, PhD

2015-10-01

Full Text Available A 16-year-old patient with recurrent palpitations and documented left bundle branch block superior axis wide complex tachycardia underwent an electrophysiological study and ablation with a zero-fluoroscopy procedure. The electrophysiological study showed a decremental antegrade conducting atriofascicular pathway. Three-dimensional CARTO-guided mapping of the tricuspid annulus in sinus rhythm was performed, and a distinct signal corresponding to the accessory pathway potential of the atriofascicular pathway was found in the posterolateral region. By using an SR0 sheath and a 4-mm-tip catheter, radiofrequency application was delivered at this point on the annulus and successfully eliminated conduction through the accessory pathway.

Persistent Atrial Fibrillation Ablation in Females: Insight from the MAGIC-AF Trial.

Science.gov (United States)

Singh, Sheldon M; D'Avila, Andre; Aryana, Arash; Kim, Young-Hoon; Mangrum, J Michael; Michaud, Gregory F; Dukkipati, Srinivas R; Heist, E Kevin; Barrett, Conor D; Thorpe, Kevin E; Reddy, Vivek Y

2016-07-27

Atrial fibrillation (AF) ablation is less frequently performed in women when compared to men. There are conflicting data on the safety and efficacy of AF ablation in women. The objective of this study was to compare the clinical characteristics and outcomes in a contemporary cohort of men and women undergoing persistent AF ablation procedures. A total of 182 men and 53 women undergoing a first-ever persistent AF catheter ablation procedure in The Modified Ablation Guided by Ibutilide Use in Chronic Atrial Fibrillation (MAGIC-AF) trial were evaluated. Clinical and procedural characteristics were compared between each gender. The primary efficacy endpoint was the 1-year single procedure freedom from atrial arrhythmia off anti-arrhythmic drugs. Women undergoing catheter ablation procedures were older than men (P Single procedure drug-free atrial arrhythmia recurrence occurred in 53% of the cohort with no difference based on gender (men = 54%, women = 53%; P = 1.0). Procedural (P = 0.04), fluoroscopic (P = 0.02), and ablation times (P = 0.003) were shorter in women compared to men. Periprocedural complications and postablation improvement in quality of life were similar between men and women. Women undergoing a first-ever persistent AF ablation procedure were older but had similar clinical outcomes and complications when compared with men. © 2016 Wiley Periodicals, Inc.

Multiphasic helical Computed Tomography of hepatocellular carcinoma. Evaluation after various percutaneous ablation procedures; Tomografia Computerizzata spirale multifasica dell'epatocarcinoma. Valutazione dopo differenti procedure ablative percutanee

Energy Technology Data Exchange (ETDEWEB)

Catalano, O.; Esposito, M.; Lobianco, R.; Cusati, B.; Altei, F.; Siani, A. [Ospedale S. Maria delle Grazie, Pozzuoli, NA (Italy). Servizio di Radiologia

1999-12-01

The purpose of this paper is to report the personal experience with helical CT evaluation of hepatocellular carcinoma treated with various percutaneous interventional procedures. From December 1996 to September 1998 it were examined with helical CT 41 patients (73 nodules in all) with hepatocellular carcinoma treated with percutaneous ablation therapies: conventional ethanol injection in 18 subjects (31 nodules), one-shot ethanol injection 3 (8 nodules), radiofrequency thermal ablation in 16 (25 nodules), and combined chemo embolization and ethanol injection in 4 (9 nodules). CT performed was 4-27 days after the last session, acquiring biphasic volumetric images in 14 patients and triphasic volumetric images in 27. A second treatment with subsequent CT study was performed for 28 lesions; 15 underwent 3 serial studies and 6 underwent 4 studies. Compared with pretreatment findings, the diameter was unchanged in 62% of the nodules and increased in 38%. Morphology was unchanged in 63% of the lesions while in 37% a mild deformation toward the needle path or a more regular and round shape was evident. Borders were unchanged in 37% of the cases and modified in 63%, appearing well-defined in 73% and ill-defined in 27%. The necrotic portion had a low attenuation with a nodule-to-parenchyma gradient more evident on delayed than on venous and finally arterial acquisitions; 8% of the lesions were not recognizable on unenhanced scans. During the arterial phase the residual tumor appeared hyperdense in 97% of the nodules and isodense in 3%, while during the portal phase it was hyperdense in 22%, isodense in 28% and hypodense in 50%, and during the delayed phase hypodense in 100%. Residual viable tissue was identified in 44% of the nodules and quantified as 100% in 1% of all lesions, > 75% in 3%, > 50% in 4%, > 25% in 23%. In conclusion, multiple-phase helical CT allows optimal depiction of primitive liver nodules treated with percutaneous interventional procedures and has a

Sex differences in a human analogue of the Radial Arm Maze: the "17-Box Maze Test".

Science.gov (United States)

Rahman, Qazi; Abrahams, Sharon; Jussab, Fardin

2005-08-01

This study investigated sex differences in spatial memory using a human analogue of the Radial Arm Maze: a revision on the Nine Box Maze originally developed by called the 17-Box Maze Test herein. The task encourages allocentric spatial processing, dissociates object from spatial memory, and incorporates a within-participants design to provide measures of location and object, working and reference memory. Healthy adult males and females (26 per group) were administered the 17-Box Maze Test, as well as mental rotation and a verbal IQ test. Females made significantly fewer errors on this task than males. However, post hoc analysis revealed that the significant sex difference was specific to object, rather than location, memory measures. These were medium to large effect sizes. The findings raise the issue of task- and component-specific sexual dimorphism in cognitive mapping.

Thermal Ablation for Benign Thyroid Nodules: Radiofrequency and Laser

Energy Technology Data Exchange (ETDEWEB)

Baek, Jung Hwan; Lee, Jeong Hyun [University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of); Valcavi, Roberto [Endocrinology Division and Thyroid Disease Center, Arcispedale Santa Maria Nuova, Reggio Emilia (Italy); Pacella, Claudio M. [Diagnostic Imaging and Interventional Radiology Department, Ospedale Regina Apostolorum, Albano Laziale-Rome (IT); Rhim, Hyun Chul [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Na, Dong Kyu [Human Medical Imaging and Intervention Center, Seoul (Korea, Republic of)

2011-10-15

Although ethanol ablation has been successfully used to treat cystic thyroid nodules, this procedure is less effective when the thyroid nodules are solid. Radiofrequency (RF) ablation, a newer procedure used to treat malignant liver tumors, has been valuable in the treatment of benign thyroid nodules regardless of the extent of the solid component. This article reviews the basic physics, techniques, applications, results, and complications of thyroid RF ablation, in comparison to laser ablation.

Navigation for fluoroscopy-guided cryo-balloon ablation procedures of atrial fibrillation

Science.gov (United States)

Bourier, Felix; Brost, Alexander; Kleinoeder, Andreas; Kurzendorfer, Tanja; Koch, Martin; Kiraly, Attila; Schneider, Hans-Juergen; Hornegger, Joachim; Strobel, Norbert; Kurzidim, Klaus

2012-02-01

Atrial fibrillation (AFib), the most common arrhythmia, has been identified as a major cause of stroke. The current standard in interventional treatment of AFib is the pulmonary vein isolation (PVI). PVI is guided by fluoroscopy or non-fluoroscopic electro-anatomic mapping systems (EAMS). Either classic point-to-point radio-frequency (RF)- catheter ablation or so-called single-shot-devices like cryo-balloons are used to achieve electrically isolation of the pulmonary veins and the left atrium (LA). Fluoroscopy-based systems render overlay images from pre-operative 3-D data sets which are then merged with fluoroscopic imaging, thereby adding detailed 3-D information to conventional fluoroscopy. EAMS provide tracking and visualization of RF catheters by means of electro-magnetic tracking. Unfortunately, current navigation systems, fluoroscopy-based or EAMS, do not provide tools to localize and visualize single shot devices like cryo-balloon catheters in 3-D. We present a prototype software for fluoroscopy-guided ablation procedures that is capable of superimposing 3-D datasets as well as reconstructing cyro-balloon catheters in 3-D. The 3-D cyro-balloon reconstruction was evaluated on 9 clinical data sets, yielded a reprojected 2-D error of 1.72 mm +/- 1.02 mm.

Advances in Imaging for Atrial Fibrillation Ablation

International Nuclear Information System (INIS)

D'Silva, A.; Wright, M.; Wright, M.

2011-01-01

Over the last fifteen years, our understanding of the pathophysiology of atrial fibrillation (AF) has paved the way for ablation to be utilized as an effective treatment option. With the aim of gaining more detailed anatomical representation, advances have been made using various imaging modalities, both before and during the ablation procedure, in planning and execution. Options have flourished from procedural fluoroscopy, electro anatomic mapping systems, pre procedural computed tomography (CT), magnetic resonance imaging (MRI), ultrasound, and combinations of these technologies. Exciting work is underway in an effort to allow the electro physiologist to assess scar formation in real time. One advantage would be to lessen the learning curve for what are very complex procedures. The hope of these developments is to improve the likelihood of a successful ablation procedure and to allow more patients access to this treatment

Endometrial ablation: normal appearance and complications.

Science.gov (United States)

Drylewicz, Monica R; Robinson, Kathryn; Siegel, Cary Lynn

2018-03-14

Global endometrial ablation is a commonly performed, minimally invasive technique aimed at improving/resolving abnormal uterine bleeding and menorrhagia in women. As non-resectoscopic techniques have come into existence, endometrial ablation performance continues to increase due to accessibility and decreased requirements for operating room time and advanced technical training. The increased utilization of this method translates into increased imaging of patients who have undergone the procedure. An understanding of the expected imaging appearances of endometrial ablation using different modalities is important for the abdominal radiologist. In addition, the frequent usage of the technique naturally comes with complications requiring appropriate imaging work-up. We review the expected appearance of the post-endometrial ablated uterus on multiple imaging modalities and demonstrate the more common and rare complications seen in the immediate post-procedural time period and remotely.

Vdrive Evaluation of Remote Steering and Testing in Lasso Electrophysiology Procedures Study: The VERSATILE Study in Atrial Fibrillation Ablation.

Science.gov (United States)

Nölker, Georg; Schwagten, Bruno; Deville, J Brian; Burkhardt, J David; Horton, Rodney P; Sha, Qun; Tomassoni, Gery

2016-03-01

Circular mapping catheters (CMC) are an essential tool in most atrial fibrillation ablation procedures. The Vdrive™ with V-Loop™ system enables a physician to remotely manipulate a CMC during electrophysiology studies. Our aim was to compare the clinical performance of the system to conventional CMC navigation according to efficiency and safety endpoints. A total of 120 patients scheduled to undergo a CMC study followed by pulmonary vein isolation (PVI) were included. Treatment allocation was randomized 2:1, remote navigation:manual navigation. The primary effectiveness endpoint was assessed based on both successful navigation to the targeted pulmonary vein (PV) and successful recording of PV electrograms. All PVs were treated independently within and between patients. The primary safety endpoint was assessed based on the occurrence of major adverse events (MAEs) through seven days after the study procedure. Primary effectiveness endpoints were achieved in 295/302 PVs in the Vdrive arm (97.7%) and 167/167 PVs in the manual arm (100%). Effectiveness analysis indicates Vdrive non-inferiority (pnon-inferiority = 0.0405; δ = -0.05) per the Cochran-Mantel-Haenszel test adjusted for PV correlation. Five MAEs related to the ablation procedure occurred (three in the Vdrive arm-3.9%; two in the manual arm-2.33%). No device-related MAEs were observed; safety analysis indicates Vdrive non-inferiority (pnon-inferiority = 0.0441; δ = 0.07) per the normal Z test. Remote navigation of a CMC is equivalent to manual in PVI in terms of safety and effectiveness. This allows for single-operator procedures in conjunction with a magnetically guided ablation catheter. © 2016 Wiley Periodicals, Inc.

Image-Guided Spinal Ablation: A Review

Energy Technology Data Exchange (ETDEWEB)

Tsoumakidou, Georgia, E-mail: gtsoumakidou@yahoo.com; Koch, Guillaume, E-mail: guillaume.koch@chru-strasbourg.fr; Caudrelier, Jean, E-mail: jean.caudrelier@chru-strasbourg.fr; Garnon, Julien, E-mail: julien.garnon@chru-strasbourg.fr; Cazzato, Roberto Luigi, E-mail: roberto-luigi.cazzato@chru-strasbourg.fr; Edalat, Faramarz, E-mail: faramarz.edalat@gmail.com; Gangi, Afshin, E-mail: gangi@unistra.fr [Strasbourg University Hospital (France)

2016-09-15

The image-guided thermal ablation procedures can be used to treat a variety of benign and malignant spinal tumours. Small size osteoid osteoma can be treated with laser or radiofrequency. Larger tumours (osteoblastoma, aneurysmal bone cyst and metastasis) can be addressed with radiofrequency or cryoablation. Results on the literature of spinal microwave ablation are scarce, and thus it should be used with caution. A distinct advantage of cryoablation is the ability to monitor the ice-ball by intermittent CT or MRI. The different thermal insulation, temperature and electrophysiological monitoring techniques should be applied. Cautious pre-procedural planning and intermittent intra-procedural monitoring of the ablation zone can help reduce neural complications. Tumour histology, patient clinical-functional status and life-expectancy should define the most efficient and least disabling treatment option.

Induction of habits in rats by a forced-choice procedure in T-maze and the effect of pre-test free exploration

DEFF Research Database (Denmark)

Moustgaard, Anette; Hau, Jann

2009-01-01

the opportunity to explore the entire maze immediately before the free-choice challenge after 200 forced-choice trials, this resulted in a large variation in the choice pattern of the individual rats, and a subgroup of rats choose the newly opened maze arm in 95-100% of the 20 free-choice trials....

Problem-solving in English through business mazes

CERN Document Server

Farthing, Joni

1981-01-01

We choose our job carefully. What we cannot choose are our colleagues - so it's not surprising that conflict and friction can arise in our working relationships. Business Mazes presents such problems for you to solve. Follow a route through the maze ans see the outcome of each decision you make. You may find that the quickest rout isn't always the best, or the easiest, in the long run. Business Mazes is designed for intermediate and advanced level students of English, working alone or in groups. It includes full teaching plans and exercises. The mazes may also be used effectively as an interesting approach to discussion for young people preparing their first job.

Combination acetabular radiofrequency ablation and cementoplasty using a navigational radiofrequency ablation device and ultrahigh viscosity cement: technical note.

Science.gov (United States)

Wallace, Adam N; Huang, Ambrose J; Vaswani, Devin; Chang, Randy O; Jennings, Jack W

2016-03-01

Percutaneous radiofrequency ablation and cementoplasty is an alternative palliative therapy for painful metastases involving axial load-bearing bones. This technical report describes the use of a navigational radiofrequency probe to ablate acetabular metastases from an anterior approach followed by instillation of ultrahigh viscosity cement under CT-fluoroscopic guidance. The tumor ablation databases of two institutions were retrospectively reviewed to identify patients who underwent combination acetabular radiofrequency ablation and cementoplasty using the STAR Tumor Ablation and StabiliT Vertebral Augmentation Systems (DFINE; San Jose, CA). Pre-procedure acetabular tumor volume was measured on cross-sectional imaging. Pre- and post-procedure pain scores were measured using the Numeric Rating Scale (10-point scale) and compared. Partial pain improvement was categorically defined as ≥ 2-point pain score reduction. Patients were evaluated for evidence of immediate complications. Electronic medical records were reviewed for evidence of delayed complications. During the study period, 12 patients with acetabular metastases were treated. The median tumor volume was 54.3 mL (range, 28.3-109.8 mL). Pre- and post-procedure pain scores were obtained from 92% (11/12) of the cohort. The median pre-procedure pain score was 8 (range, 3-10). Post-procedure pain scores were obtained 7 days (82%; 9/11), 11 days (9.1%; 1/11) or 21 days (9.1%; 1/11) after treatment. The median post-treatment pain score was 3 (range, 1-8), a statistically significant difference compared with pre-treatment (P = 0.002). Categorically, 73% (8/11) of patients reported partial pain relief after treatment. No immediate symptomatic complications occurred. Three patients (25%; 3/12) were discharged to hospice within 1 week of treatment. No delayed complications occurred in the remaining 75% (9/12) of patients during median clinical follow-up of 62 days (range, 14-178 days). Palliative percutaneous

Imaging in percutaneous ablation for atrial fibrillation

Energy Technology Data Exchange (ETDEWEB)

Maksimovic, Ruzica [Erasmus Medical Center, Department of Radiology, GD Rotterdam (Netherlands); Institute for Cardiovascular Diseases of the University Medical Center, Belgrade (Czechoslovakia); Dill, Thorsten [Kerckhoff-Heart Center, Department of Cardiology, Bad Nauheim (Germany); Ristic, Arsen D.; Seferovic, Petar M. [Institute for Cardiovascular Diseases of the University Medical Center, Belgrade (Czechoslovakia)

2006-11-15

Percutaneous ablation for electrical disconnection of the arrhythmogenic foci using various forms of energy has become a well-established technique for treating atrial fibrillation (AF). Success rate in preventing recurrence of AF episodes is high although associated with a significant incidence of pulmonary vein (PV) stenosis and other rare complications. Clinical workup of AF patients includes imaging before and after ablative treatment using different noninvasive and invasive techniques such as conventional angiography, transoesophageal and intracardiac echocardiography, computed tomography (CT) and magnetic resonance imaging (MRI), which offer different information with variable diagnostic accuracy. Evaluation before percutaneous ablation involves assessment of PVs (PV pattern, branching pattern, orientation and ostial size) to facilitate position and size of catheters and reduce procedure time as well as examining the left atrium (presence of thrombi, dimensions and volumes). Imaging after the percutaneous ablation is important for assessment of overall success of the procedure and revealing potential complications. Therefore, imaging methods enable depiction of PVs and the anatomy of surrounding structures essential for preprocedural management and early detection of PV stenosis and other ablation-related procedures, as well as long-term follow-up of these patients. (orig.)

Imaging in percutaneous ablation for atrial fibrillation

International Nuclear Information System (INIS)

Maksimovic, Ruzica; Dill, Thorsten; Ristic, Arsen D.; Seferovic, Petar M.

2006-01-01

Percutaneous ablation for electrical disconnection of the arrhythmogenic foci using various forms of energy has become a well-established technique for treating atrial fibrillation (AF). Success rate in preventing recurrence of AF episodes is high although associated with a significant incidence of pulmonary vein (PV) stenosis and other rare complications. Clinical workup of AF patients includes imaging before and after ablative treatment using different noninvasive and invasive techniques such as conventional angiography, transoesophageal and intracardiac echocardiography, computed tomography (CT) and magnetic resonance imaging (MRI), which offer different information with variable diagnostic accuracy. Evaluation before percutaneous ablation involves assessment of PVs (PV pattern, branching pattern, orientation and ostial size) to facilitate position and size of catheters and reduce procedure time as well as examining the left atrium (presence of thrombi, dimensions and volumes). Imaging after the percutaneous ablation is important for assessment of overall success of the procedure and revealing potential complications. Therefore, imaging methods enable depiction of PVs and the anatomy of surrounding structures essential for preprocedural management and early detection of PV stenosis and other ablation-related procedures, as well as long-term follow-up of these patients. (orig.)

A Maze Game on Android Using Growing Tree Method

Science.gov (United States)

Hendrawan, Y. F.

2018-01-01

A maze is a type of puzzle games where a player moves in complex and branched passages to find a particular target or location. One method to create a maze is the Growing Tree method. The method creates a tree that has branches which are the paths of a maze. This research explored three types of Growing Tree method implementations for maze generation on Android mobile devices. The layouts produced could be played in first and third-person perspectives. The experiment results showed that it took 17.3 seconds on average to generate 20 cells x 20 cells dynamic maze layouts.

Optimization of Apparatus Design and Behavioral Measures for the Assessment of Visuo-Spatial Learning and Memory of Mice on the Barnes Maze

Science.gov (United States)

O'Leary, Timothy P.; Brown, Richard E.

2013-01-01

We have previously shown that apparatus design can affect visual-spatial cue use and memory performance of mice on the Barnes maze. The present experiment extends these findings by determining the optimal behavioral measures and test procedure for analyzing visuo-spatial learning and memory in three different Barnes maze designs. Male and female…

Relationships between cardiac innervation/perfusion imbalance and ventricular arrhythmias: impact on invasive electrophysiological parameters and ablation procedures

International Nuclear Information System (INIS)

Gimelli, Alessia; Menichetti, Francesca; Soldati, Ezio; Liga, Riccardo; Vannozzi, Andrea; Bongiorni, Maria Grazia; Marzullo, Paolo

2016-01-01

To assess the relationship between regional myocardial perfusion and sympathetic innervation parameters at myocardial scintigraphy and intra-cavitary electrophysiological data in patients with ventricular arrhythmias (VA) submitted to invasive electrophysiological study and ablation procedure. Sixteen subjects underwent invasive electrophysiological study with electroanatomical mapping (EAM) followed by trans-catheter ablations of VA. Before ablation all patients were studied with a combined evaluation of regional myocardial perfusion and sympathetic innervation by means of tomographic "9"9"mTc-tetrofosmin and "1"2"3I- metaiodobenzylguanidine cadmium-zinc-telluride (CZT) scintigraphies, respectively. Off-line spatial co-registration of CZT perfusion and innervation data with the three-dimensional EAM reconstruction was performed in every patient. CZT revealed the presence of myocardial scar in 55 (20 %) segments. Of the viable myocardial segments, 131 (60 %) presented a preserved adrenergic innervation, while 86 (40 %) showed a significantly depressed innervation (i.e. innervation/perfusion mismatch). On EAM, the invasively measured intra-cavitary voltage was significantly lower in scarred segments than in viable ones (1.7 ± 1.5 mV vs. 4.0 ± 2.2 mV, P < 0.001). Interestingly, among the viable segments, those showing an innervation/perfusion mismatch presented a significantly lower intra-cavitary voltage than those with preserved innervation (1.9 ± 2.5 mV vs. 4.7 ± 2.3 mV, P < 0.001). Intra-cardiac ablation was performed in 63 (23 %) segments. On multivariate analysis, after correction for scar burden, the segments showing an innervation/perfusion mismatch remained the most frequent ablation targets (OR 5.6, 95 % CI 1.5-20.8; P = 0.009). In patients with VA, intra-cavitary electrical abnormalities frequently originate at the level of viable myocardial segments with depressed sympathetic innervation that frequently represents the ultimate ablation target. (orig.)

Relationships between cardiac innervation/perfusion imbalance and ventricular arrhythmias: impact on invasive electrophysiological parameters and ablation procedures

Energy Technology Data Exchange (ETDEWEB)

Gimelli, Alessia [Fondazione Toscana Gabriele Monasterio, Pisa (Italy); Menichetti, Francesca; Soldati, Ezio; Liga, Riccardo; Vannozzi, Andrea; Bongiorni, Maria Grazia [University Hospital of Pisa, Cardio-Thoracic and Vascular Department, Pisa (Italy); Marzullo, Paolo [Fondazione Toscana Gabriele Monasterio, Pisa (Italy); CNR, Institute of Clinical Physiology, Pisa (Italy)

2016-12-15

To assess the relationship between regional myocardial perfusion and sympathetic innervation parameters at myocardial scintigraphy and intra-cavitary electrophysiological data in patients with ventricular arrhythmias (VA) submitted to invasive electrophysiological study and ablation procedure. Sixteen subjects underwent invasive electrophysiological study with electroanatomical mapping (EAM) followed by trans-catheter ablations of VA. Before ablation all patients were studied with a combined evaluation of regional myocardial perfusion and sympathetic innervation by means of tomographic {sup 99m}Tc-tetrofosmin and {sup 123}I- metaiodobenzylguanidine cadmium-zinc-telluride (CZT) scintigraphies, respectively. Off-line spatial co-registration of CZT perfusion and innervation data with the three-dimensional EAM reconstruction was performed in every patient. CZT revealed the presence of myocardial scar in 55 (20 %) segments. Of the viable myocardial segments, 131 (60 %) presented a preserved adrenergic innervation, while 86 (40 %) showed a significantly depressed innervation (i.e. innervation/perfusion mismatch). On EAM, the invasively measured intra-cavitary voltage was significantly lower in scarred segments than in viable ones (1.7 ± 1.5 mV vs. 4.0 ± 2.2 mV, P < 0.001). Interestingly, among the viable segments, those showing an innervation/perfusion mismatch presented a significantly lower intra-cavitary voltage than those with preserved innervation (1.9 ± 2.5 mV vs. 4.7 ± 2.3 mV, P < 0.001). Intra-cardiac ablation was performed in 63 (23 %) segments. On multivariate analysis, after correction for scar burden, the segments showing an innervation/perfusion mismatch remained the most frequent ablation targets (OR 5.6, 95 % CI 1.5-20.8; P = 0.009). In patients with VA, intra-cavitary electrical abnormalities frequently originate at the level of viable myocardial segments with depressed sympathetic innervation that frequently represents the ultimate ablation target

Randomized, Split-Face/Décolleté Comparative Trial of Procedure Enhancement System for Fractional non-Ablative Laser Resurfacing Treatment.

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Robinson, Deanne Mraz; Frulla, Ashton P

2017-07-01

INTRODUCTION: A topical proprietary procedural enhancement system (PES) containing a combination of active ingredients including a tripeptide and hexapeptide (TriHex Technology™, Alastin Procedure Enhancement Invasive System, ALASTIN Skincare™, Inc., Carlsbad, CA) has been used successfully to aid in healing and improve symptomatology following resurfacing procedures. METHODS: PES (Gentle Cleanser, Regenerating Skin Nectar with TriHex Technology™, Ultra Nourishing Moisturizer with TriHex Technology™, Soothe + Protect Recovery Balm, Broad Spectrum 30+ Sunscreen) was compared to a basic regimen (Aquaphor™, Cerave™ cleanser, Vanicream™, Alastin Broad Spectrum 30+ Sunscreen) in a split face/ décolleté trial following fractional non-ablative thulium-doped resurfacing treatment to the face or décolleté. The skin was pre-conditioned and treated during and after the procedure using the two regimens. RESULTS: A blinded investigator rated the PES statistically superior to the basic regimen on healing post-laser treatment on day 4 based on lentigines, texture, and Global Skin Quality. Subjects also reported 'better looking and feeling' skin on the PES side. CONCLUSION: PES appears to improve healing post-non ablative thulium-doped resurfacing treatment to the face/décolleté in comparison with standard of care. J Drugs Dermatol. 2017;16(7):707-710..

Burn, freeze, or photo-ablate?: comparative symptom profile in Barrett's dysplasia patients undergoing endoscopic ablation

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Gill, Kanwar Rupinder S.; Gross, Seth A.; Greenwald, Bruce D.; Hemminger, Lois L.; Wolfsen, Herbert C.

2009-06-01

Background: There are few data available comparing endoscopic ablation methods for Barrett's esophagus with high-grade dysplasia (BE-HGD). Objective: To determine differences in symptoms and complications associated with endoscopic ablation. Design: Prospective observational study. Setting: Two tertiary care centers in USA. Patients: Consecutive patients with BE-HGD Interventions: In this pilot study, symptoms profile data were collected for BE-HGD patients among 3 endoscopic ablation methods: porfimer sodium photodynamic therapy, radiofrequency ablation and low-pressure liquid nitrogen spray cryotherapy. Main Outcome Measurements: Symptom profiles and complications from the procedures were assessed 1-8 weeks after treatment. Results: Ten BE-HGD patients were treated with each ablation modality (30 patients total; 25 men, median age: 69 years (range 53-81). All procedures were performed in the clinic setting and none required subsequent hospitalization. The most common symptoms among all therapies were chest pain, dysphagia and odynophagia. More patients (n=8) in the porfimer sodium photodynamic therapy group reported weight loss compared to radio-frequency ablactation (n=2) and cryotherapy (n=0). Four patients in the porfimer sodium photodynamic therapy group developed phototoxicity requiring medical treatment. Strictures, each requiring a single dilation, were found in radiofrequency ablactation (n=1) and porfimer sodium photodynamic therapy (n=2) patients. Limitations: Small sample size, non-randomized study. Conclusions: These three endoscopic therapies are associated with different types and severity of post-ablation symptoms and complications.

Benign thyroid nodule unresponsive to radiofrequency ablation treated with laser ablation: a case report.

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Oddo, Silvia; Balestra, Margherita; Vera, Lara; Giusti, Massimo

2018-05-11

Radiofrequency ablation and laser ablation are safe and effective techniques for reducing thyroid nodule volume, neck symptoms, and cosmetic complaints. Therapeutic success is defined as a nodule reduction > 50% between 6 and 12 months after the procedure, but a percentage of nodules inexplicably do not respond to thermal ablation. We describe the case of a young Caucasian woman with a solid benign thyroid nodule who refused surgery and who had undergone radiofrequency ablation in 2013. The nodule did not respond in terms of either volume reduction or improvement in neck symptoms. After 2 years, given the patient's continued refusal of thyroidectomy, we proposed laser ablation. The nodule displayed a significant volume reduction (- 50% from radiofrequency ablation baseline volume, - 57% from laser ablation baseline), and the patient reported a significant improvement in neck symptoms (from 6/10 to 1/10 on a visual analogue scale). We conjecture that some benign thyroid nodules may be intrinsically resistant to necrosis when one specific ablation technique is used, but may respond to another technique. To the best of our knowledge, this is the first description of the effect of performing a different percutaneous ablation technique in a nodule that does not respond to radiofrequency ablation.

Incidence and Cause of Hypertension During Adrenal Radiofrequency Ablation

International Nuclear Information System (INIS)

Yamakado, Koichiro; Takaki, Haruyuki; Yamada, Tomomi; Yamanaka, Takashi; Uraki, Junji; Kashima, Masataka; Nakatsuka, Atsuhiro; Takeda, Kan

2012-01-01

Purpose: To evaluate the incidence and cause of hypertension prospectively during adrenal radiofrequency ablation (RFA). Methods: For this study, approved by our institutional review board, written informed consent was obtained from all patients. Patients who received RFA for adrenal tumors (adrenal ablation) and other abdominal tumors (nonadrenal ablation) were included in this prospective study. Blood pressure was monitored during RFA. Serum adrenal hormone levels including epinephrine, norepinephrine, dopamine, and cortisol levels were measured before and during RFA. The respective incidences of procedural hypertension (systolic blood pressure >200 mmHg) of the two patient groups were compared. Factors correlating with procedural systolic blood pressure were evaluated by regression analysis.ResultsNine patients underwent adrenal RFA and another 9 patients liver (n = 5) and renal (n = 4) RFA. Asymptomatic procedural hypertension that returned to the baseline by injecting calcium blocker was found in 7 (38.9%) of 18 patients. The incidence of procedural hypertension was significantly higher in the adrenal ablation group (66.7%, 6/9) than in the nonadrenal ablation group (11.1%, 1/9, P 2 = 0.68, P 2 = 0.72, P < 0.0001) levels during RFA. The other adrenal hormones did not show correlation with procedural systolic blood pressure. Conclusion: Hypertension occurs frequently during adrenal RFA because of the release of catecholamine.

Radiofrequency thermal ablation of malignant hepatic tumors: post-ablation syndrome

International Nuclear Information System (INIS)

Choi, Jung Bin; Rhim, Hyunchul; Kim, Yongsoo; Koh, Byung Hee; Cho, On Koo; Seo, Heung Suk; Lee, Seung Ro

2000-01-01

To evaluate post-ablation syndrome after radiofrequency thermal ablation of malignant hepatic tumors. Forty-two patients with primary (n=3D29) or secondary (n=3D13) hepatic tumors underwent radiofrequency thermal ablation. A total of 65 nodules ranging in size from 1.1 to 5.0 (mean, 3.1) cm were treated percutaneously using a 50W RF generator with 15G expandable needle electrodes. We retrospectively evaluated the spectrum of post-ablation syndrome including pain, fever (≥3D 38 deg C), nausea, vomiting, right shoulder pain, and chest discomfort according to frequency, intensity and duration, and the findings were correlated with tumor location and number of ablations. We also evaluated changes in pre-/post-ablation serum aminotransferase (ALT/AST) and prothrombin time, and correlated these findings with the number of ablations. Post-ablation syndrome was noted in 29 of 42 patients (69.0%), and most symptoms improved with conservative treatment. The most important of these were abdominal plan (n=3D20, 47.6%), fever (n=3D8, 19.0%), and nausea (n=3D7, 16.7%), and four of 42 (9.5%) patients complained of severe pain. The abdominal pain lasted from 3 hours to 5.5 days (mean; 20.4 hours), the fever from 6 hours to 5 days (mean; 63.0 hours). And the nausea from 1 hours to 4 days (mean; 21.0 hours). Other symptoms were right shoulder pain (n=3D6, 14.3%), chest discomfort (n=3D3, 7.1%), and headache (n=3D3, 7.1%). Seventeen of 20 patients (85%) with abdominal pain had subcapsular tumor of the liver. There was significant correlation between pain, location of the tumor, and a number of ablations. After ablation, ALT/AST was elevated more than two-fold in 52.6%/73.7% of patients, respectively but there was no significant correlation with the number of ablation. Post-ablation syndrome is a frequent and tolerable post-procedural process after radiofrequency thermal ablation. The spectrum of this syndrome provides a useful guideline for the post-ablation management. (author)

Intelligence-Augmented Rat Cyborgs in Maze Solving.

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Yipeng Yu

Full Text Available Cyborg intelligence is an emerging kind of intelligence paradigm. It aims to deeply integrate machine intelligence with biological intelligence by connecting machines and living beings via neural interfaces, enhancing strength by combining the biological cognition capability with the machine computational capability. Cyborg intelligence is considered to be a new way to augment living beings with machine intelligence. In this paper, we build rat cyborgs to demonstrate how they can expedite the maze escape task with integration of machine intelligence. We compare the performance of maze solving by computer, by individual rats, and by computer-aided rats (i.e. rat cyborgs. They were asked to find their way from a constant entrance to a constant exit in fourteen diverse mazes. Performance of maze solving was measured by steps, coverage rates, and time spent. The experimental results with six rats and their intelligence-augmented rat cyborgs show that rat cyborgs have the best performance in escaping from mazes. These results provide a proof-of-principle demonstration for cyborg intelligence. In addition, our novel cyborg intelligent system (rat cyborg has great potential in various applications, such as search and rescue in complex terrains.

Intelligence-Augmented Rat Cyborgs in Maze Solving.

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Yu, Yipeng; Pan, Gang; Gong, Yongyue; Xu, Kedi; Zheng, Nenggan; Hua, Weidong; Zheng, Xiaoxiang; Wu, Zhaohui

2016-01-01

Cyborg intelligence is an emerging kind of intelligence paradigm. It aims to deeply integrate machine intelligence with biological intelligence by connecting machines and living beings via neural interfaces, enhancing strength by combining the biological cognition capability with the machine computational capability. Cyborg intelligence is considered to be a new way to augment living beings with machine intelligence. In this paper, we build rat cyborgs to demonstrate how they can expedite the maze escape task with integration of machine intelligence. We compare the performance of maze solving by computer, by individual rats, and by computer-aided rats (i.e. rat cyborgs). They were asked to find their way from a constant entrance to a constant exit in fourteen diverse mazes. Performance of maze solving was measured by steps, coverage rates, and time spent. The experimental results with six rats and their intelligence-augmented rat cyborgs show that rat cyborgs have the best performance in escaping from mazes. These results provide a proof-of-principle demonstration for cyborg intelligence. In addition, our novel cyborg intelligent system (rat cyborg) has great potential in various applications, such as search and rescue in complex terrains.

LASER treatment for women with high-grade vaginal intraepithelial neoplasia: A propensity-matched analysis on the efficacy of ablative versus excisional procedures.

Science.gov (United States)

Bogani, Giorgio; Ditto, Antonino; Martinelli, Fabio; Mosca, Lavinia; Chiappa, Valentina; Rossetti, Diego; Leone Roberti Maggiore, Umberto; Sabatucci, Ilaria; Lorusso, Domenica; Raspagliesi, Francesco

2018-05-14

To investigate the long-term effectiveness of LASER treatment in women affected by high-grade vaginal intra-epithelial neoplasia. Data of consecutive women treated for high-grade vaginal intra-epithelial neoplasia were retrieved. Efficacy and long-term effectiveness of ablative and excisional procedures were tested using a propensity-matched algorithm. Risk of recurrence over the time was assessed using Kaplan-Meier and Cox models. Overall, 204 patients met the inclusion criteria. LASER ablation and exicision were performed in 169 (82.8%) and 35 (17.2%) patients. A total of 41 (20%) patients developed high-grade vaginal intraepithelial neoplasia at a median follow-up of 65 (range, 6-120) months. We observed that only HPV persistence (HR: 2.37 [95%CI:1.03, 5.42]; P = 0.04) was associated with the risk of recurrence at multivariate analysis. Seven (3.4%) invasive cancers of the lower genital tract were observed in our population. Considering the efficacy of type of procedure (after we applied the propensity-matched analysis), we observed that type of procedure did not influence persistence of HPV infection (22.8% after excision and 15.7% after ablation; P = 0.424). Similarly, recurrence (17.1% vs. 18.6%; P = 1.00) and lower genital tract (2.8% vs. 1.4%; P = 1.00) rates were similar between groups. Women affected by high-grade vaginal intra-epithelial neoplasia are at high risk of recurrence. LASER ablation seems to be equivalent to excision in term of long-term effectiveness. Lasers Surg. Med. 9999:1-7, 2018. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

Memory-Enhancing Activity of Palmatine in Mice Using Elevated Plus Maze and Morris Water Maze

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Dinesh Dhingra

2012-01-01

Full Text Available The present study was designed to evaluate the effect of palmatine on memory of Swiss young male albino mice. Palmatine (0.1, 0.5, 1 mg/kg, i.p. and physostigmine (0.1 mg/kg, i.p. per se were administered for 10 successive days to separate groups of mice. Effect of drugs on learning and memory of mice was evaluated using elevated plus maze and Morris water maze. Brain acetylcholinesterase activity was also estimated. Effect of palmatine on scopolamine- and diazepam-induced amnesia was also investigated. Palmatine (0.5 and 1 mg/kg and physostigmine significantly improved learning and memory of mice, as indicated by decrease in transfer latency using elevated plus maze, and decrease in escape latency during training and increase in time spent in target quadrant during retrieval using Morris water maze. The drugs did not show any significant effect on locomotor activity of the mice. Memory-enhancing activity of palmatine (1 mg/kg was comparable to physostigmine. Palmatine (1 mg/kg significantly reversed scopolamine- and diazepam-induced amnesia in mice. Palmatine and physostigmine also significantly reduced brain acetylcholinesterase activity of mice. Thus, palmatine showed memory-enhancing activity in mice probably by inhibiting brain acetylcholinesterase activity, through involvement of GABA-benzodiazepine pathway, and due to its antioxidant activity.

Distinction between epigenic and hypogenic maze caves

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Palmer, Arthur N.

2011-11-01

Certain caves formed by dissolution of bedrock have maze patterns composed of closed loops in which many intersecting fractures or pores have enlarged simultaneously. Their origin can be epigenic (by shallow circulation of meteoric groundwater) or hypogenic (by rising groundwater or production of deep-seated solutional aggressiveness). Epigenic mazes form by diffuse infiltration through a permeable insoluble caprock or by floodwater supplied by sinking streams. Most hypogenic caves involve deep sources of aggressiveness. Transverse hypogenic cave origin is a recently proposed concept in which groundwater of mainly meteoric origin rises across strata in the distal portions of large flow systems, to form mazes in soluble rock sandwiched between permeable but insoluble strata. The distinction between maze types is debated and is usually based on examination of diagnostic cave features and relation of caves to their regional setting. In this paper, the principles of mass transfer are applied to clarify the limits of each model, to show how cave origin is related to groundwater discharge, dissolution rate, and time. The results show that diffuse infiltration and floodwater can each form maze caves at geologically feasible rates (typically within 500 ka). Transverse hypogenic mazes in limestone, to enlarge significantly within 1 Ma, require an unusually high permeability of the non-carbonate beds (generally ≥ 10-4 cm/s), large discharge, and calcite saturation no greater than 90%, which is rare in deep diffuse flow in sedimentary rocks. Deep sources of aggressiveness are usually required. The origin of caves by transverse hypogenic flow is much more favorable in evaporite rocks than in carbonate rocks.

Incidence and Cause of Hypertension During Adrenal Radiofrequency Ablation

Energy Technology Data Exchange (ETDEWEB)

Yamakado, Koichiro, E-mail: yama@clin.medic.mie-u.ac.jp; Takaki, Haruyuki [Mie University School of Medicine, Department of Interventional Radiology (Japan); Yamada, Tomomi [Mie University School of Medicine, Department of Translational Medicine (Japan); Yamanaka, Takashi; Uraki, Junji; Kashima, Masataka; Nakatsuka, Atsuhiro; Takeda, Kan [Mie University School of Medicine, Department of Interventional Radiology (Japan)

2012-12-15

Purpose: To evaluate the incidence and cause of hypertension prospectively during adrenal radiofrequency ablation (RFA). Methods: For this study, approved by our institutional review board, written informed consent was obtained from all patients. Patients who received RFA for adrenal tumors (adrenal ablation) and other abdominal tumors (nonadrenal ablation) were included in this prospective study. Blood pressure was monitored during RFA. Serum adrenal hormone levels including epinephrine, norepinephrine, dopamine, and cortisol levels were measured before and during RFA. The respective incidences of procedural hypertension (systolic blood pressure >200 mmHg) of the two patient groups were compared. Factors correlating with procedural systolic blood pressure were evaluated by regression analysis.ResultsNine patients underwent adrenal RFA and another 9 patients liver (n = 5) and renal (n = 4) RFA. Asymptomatic procedural hypertension that returned to the baseline by injecting calcium blocker was found in 7 (38.9%) of 18 patients. The incidence of procedural hypertension was significantly higher in the adrenal ablation group (66.7%, 6/9) than in the nonadrenal ablation group (11.1%, 1/9, P < 0.0498). Procedural systolic blood pressure was significantly correlated with serum epinephrine (R{sup 2} = 0.68, P < 0.0001) and norepinephrine (R{sup 2} = 0.72, P < 0.0001) levels during RFA. The other adrenal hormones did not show correlation with procedural systolic blood pressure. Conclusion: Hypertension occurs frequently during adrenal RFA because of the release of catecholamine.

Guiding brine shrimp through mazes by solving reaction diffusion equations

Science.gov (United States)

Singal, Krishma; Fenton, Flavio

Excitable systems driven by reaction diffusion equations have been shown to not only find solutions to mazes but to also to find the shortest path between the beginning and the end of the maze. In this talk we describe how we can use the Fitzhugh-Nagumo model, a generic model for excitable media, to solve a maze by varying the basin of attraction of its two fixed points. We demonstrate how two dimensional mazes are solved numerically using a Java Applet and then accelerated to run in real time by using graphic processors (GPUs). An application of this work is shown by guiding phototactic brine shrimp through a maze solved by the algorithm. Once the path is obtained, an Arduino directs the shrimp through the maze using lights from LEDs placed at the floor of the Maze. This method running in real time could be eventually used for guiding robots and cars through traffic.

Radiofrequency ablation in dermatology

Directory of Open Access Journals (Sweden)

Sachdeva Silonie

2007-01-01

Full Text Available Radiofreqeuency ablation is a versatile dermatosurgical procedure used for surgical management of skin lesions by using various forms of alternating current at an ultra high frequency. The major modalities in radiofrequency are electrosection, electrocoagulation, electrodessication and fulguration. The use of radiofrequency ablation in dermatosurgical practice has gained importance in recent years as it can be used to treat most of the skin lesions with ease in less time with clean surgical field due to adequate hemostasis and with minimal side effects and complications. This article focuses on the major tissue effects and factors influencing radiofrequency ablation and its application for various dermatological conditions.

Delayed-matching-to-place Task in a Dry Maze to Measure Spatial Working Memory in Mice.

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Feng, Xi; Krukowski, Karen; Jopson, Timothy; Rosi, Susanna

2017-07-05

The delayed-matching-to-place (DMP) dry maze test is a variant of DMP water maze (Steele and Morris, 1999; Faizi et al. , 2012) which measures spatial working/episodic-like learning and memory that depends on both hippocampal and cortical functions (Wang and Morris, 2010; Euston et al. , 2012). Using this test we can detect normal aging related spatial working memory decline, as well as trauma induced working memory deficits. Furthermore, we recently reported that fractionated whole brain irradiation does not affect working memory in mice (Feng et al. , 2016). Here we describe the experimental setup and procedures of this behavioral test.

Delayed Development of Pneumothorax After Pulmonary Radiofrequency Ablation

International Nuclear Information System (INIS)

Clasen, Stephan; Kettenbach, Joachim; Kosan, Bora; Aebert, Hermann; Schernthaner, Melanie; Kroeber, Stefan-Martin; Boemches, Andrea; Claussen, Claus D.; Pereira, Philippe L.

2009-01-01

Acute pneumothorax is a frequent complication after percutaneous pulmonary radiofrequency (RF) ablation. In this study we present three cases showing delayed development of pneumothorax after pulmonary RF ablation in 34 patients. Our purpose is to draw attention to this delayed complication and to propose a possible approach to avoid this major complication. These three cases occurred subsequent to 44 CT-guided pulmonary RF ablation procedures (6.8%) using either internally cooled or multitined expandable RF electrodes. In two patients, the pneumothorax, being initially absent at the end of the intervention, developed without symptoms. One of these patients required chest drain placement 32 h after RF ablation, and in the second patient therapy remained conservative. In the third patient, a slight pneumothorax at the end of the intervention gradually increased and led into tension pneumothorax 5 days after ablation procedure. Underlying bronchopleural fistula along the coagulated former electrode track was diagnosed in two patients. In conclusion, delayed development of pneumothorax after pulmonary RF ablation can occur and is probably due to underlying bronchopleural fistula, potentially leading to tension pneumothorax. Patients and interventionalists should be prepared for delayed onset of this complication, and extensive track ablation following pulmonary RF ablation should be avoided.

Psychometric Properties of Maze Tasks in Middle School Students

Science.gov (United States)

Tolar, Tammy D.; Barth, Amy E.; Francis, David J.; Fletcher, Jack M.; Stuebing, Karla K.; Vaughn, Sharon

2012-01-01

Maze tasks have appealing properties as progress-monitoring tools, but there is a need for a thorough examination of the psychometric properties of Maze tasks among middle school students. We evaluated form effects, reliability, validity, and practice effects of Maze among students in Grades 6 through 8. We administered the same (familiar) and…

Laser ablation of tumors: current concepts and recent developments

International Nuclear Information System (INIS)

Stroszczynski, C.; Gaffke, G.; Gnauck, M.; Ricke, J.; Felix, R.; Puls, R.; Speck, U.; Hosten, N.; Oettle, H.; Hohenberger, P.

2004-01-01

Purpose. The purpose of this paper is to present technical innovations and clinical results of percutaneous interventional laser ablation of tumors using new techniques. Methods. Laser ablation was performed in 182 patients (liver tumors: 131, non hepatic tumors - bone, lung, others: 51) after interdisciplinary consensus was obtained. The procedure was done using a combination of imaging modalities (CT/MRI, CT/US) or only closed high field MRI (1.5 T). All patients received an MRI-scan immediately after laser ablation. Results. In 90.9% of the patients with liver tumors, a complete ablation was achieved. Major events occurred in 5.4%. The technical success rate of laser ablation in non-hepatic tumors was high, clinical results differed depending on the treated organ. Conclusions. The treatment of tumors of the liver and other organs up to 5 cm by laser ablation was a safe procedure with a low rate of complications and side effects. Image guidance by MRI is advantageous for precise tumor visualization in all dimensions, therapy monitoring, and control of laser ablation results. (orig.) [de

Emergency bypass post percutaneous atrial ablation: a case report.

LENUS (Irish Health Repository)

Hargrove, M

2010-11-01

A 34-year-old male undergoing percutaneous atrial ablation procedure for paroxysmal fibrillation required emergency sternotomy for cardiac tamponade. The patient had been anticoagulated and had received plavix and aspirin prior to and during the ablation procedure. Seven units of red cell concentrate had been transfused in the cardiac catherisation laboratory. On arrival in theatre, the patient was hypotensive, but was awake on induction of anaesthesia. No recordable blood pressure with non-invasive monitoring was observed. A sternotomy was immediately performed and, on evacuation of the pericardium, a bleeding site was not visible. The patient was commenced on cardiopulmonary bypass. Bleeding site was identified and the defect closed. The patient was weaned from cardiopulmonary bypass with minimal inotropic support and made an uneventful recovery. Bypass time was 38 minutes. A literature review showed a 1% incidence of post-ablation bleeding(1). The incidence of reverting to bypass for such an event has not been reported previously. During these procedures, it might be wise to have the cardiothoracic team notified while atrial ablation procedures are being performed in the cardiac catheterization laboratory.

CT thermometry for cone-beam CT guided ablation

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DeStefano, Zachary; Abi-Jaoudeh, Nadine; Li, Ming; Wood, Bradford J.; Summers, Ronald M.; Yao, Jianhua

2016-03-01

Monitoring temperature during a cone-beam CT (CBCT) guided ablation procedure is important for prevention of over-treatment and under-treatment. In order to accomplish ideal temperature monitoring, a thermometry map must be generated. Previously, this was attempted using CBCT scans of a pig shoulder undergoing ablation.1 We are extending this work by using CBCT scans of real patients and incorporating more processing steps. We register the scans before comparing them due to the movement and deformation of organs. We then automatically locate the needle tip and the ablation zone. We employ a robust change metric due to image noise and artifacts. This change metric takes windows around each pixel and uses an equation inspired by Time Delay Analysis to calculate the error between windows with the assumption that there is an ideal spatial offset. Once the change map is generated, we correlate change data with measured temperature data at the key points in the region. This allows us to transform our change map into a thermal map. This thermal map is then able to provide an estimate as to the size and temperature of the ablation zone. We evaluated our procedure on a data set of 12 patients who had a total of 24 ablation procedures performed. We were able to generate reasonable thermal maps with varying degrees of accuracy. The average error ranged from 2.7 to 16.2 degrees Celsius. In addition to providing estimates of the size of the ablation zone for surgical guidance, 3D visualizations of the ablation zone and needle are also produced.

A Wireless EEG Recording Method for Rat Use inside the Water Maze.

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Richard C Pinnell

Full Text Available With the continued miniaturisation of portable embedded systems, wireless EEG recording techniques are becoming increasingly prevalent in animal behavioural research. However, in spite of their versatility and portability, they have seldom been used inside water-maze tasks designed for rats. As such, a novel 3D printed implant and waterproof connector is presented, which can facilitate wireless water-maze EEG recordings in freely-moving rats, using a commercial wireless recording system (W32; Multichannel Systems. As well as waterproofing the wireless system, battery, and electrode connector, the implant serves to reduce movement-related artefacts by redistributing movement-related forces away from the electrode connector. This implant/connector was able to successfully record high-quality LFP in the hippocampo-striatal brain regions of rats as they undertook a procedural-learning variant of the double-H water-maze task. Notably, there were no significant performance deficits through its use when compared with a control group across a number of metrics including number of errors and speed of task completion. Taken together, this method can expand the range of measurements that are currently possible in this diverse area of behavioural neuroscience, whilst paving the way for integration with more complex behaviours.

Radiofrequency catheter ablation for electrical storm in a patient with dilated cardiomyopathy.

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Kolettis, Theofilos M; Naka, Katerina K; Katsouras, Christos S

2005-01-01

We report a case of successful radiofrequency catheter ablation in a patient with dilated cardiomyopathy, who presented with multiple, haemodynamically poorly tolerated episodes of monomorphic ventricular tachycardia, resistant to antiarrhythmic drug treatment. The ablation procedure consisted of focal ablation of three mapped left ventricular sites, using pace and activation mapping. Additional linear ablation lesions were created across these sites. After the procedure, the patient remained free of tachycardia episodes and seven days post-ablation he underwent implantation of a cardioverter-defibrillator. During a twelve-month follow-up period, the patient has remained free of monomorphic ventricular tachycardia episodes. Radiofrequency catheter ablation is feasible in electrical storm, using conventional mapping techniques, even in haemodynamically unstable tachycardias.

Percutaneous treatment of hepatocellular carcinoma in patients with cirrhosis: A comparison of the safety of cryoablation and radiofrequency ablation

International Nuclear Information System (INIS)

Dunne, Ruth M.; Shyn, Paul B.; Sung, Jeffrey C.; Tatli, Servet; Morrison, Paul R.; Catalano, Paul J.; Silverman, Stuart G.

2014-01-01

Purpose: To compare the safety of image-guided percutaneous cryoablation and radiofrequency ablation in the treatment of hepatocellular carcinoma in patients with cirrhosis. Materials and methods: This retrospective HIPAA-compliant study received institutional review board approval. Forty-two adult patients with cirrhosis underwent image-guided percutaneous ablation of hepatocellular carcinoma from 2003 to 2011. Twenty-five patients underwent 33 cryoablation procedures to treat 39 tumors, and 22 underwent 30 radiofrequency ablation procedures to treat 39 tumors. Five patients underwent both cryoablation and radiofrequency ablation procedures. Complication rates and severity per procedure were compared between the ablation groups. Potential confounding patient, procedure, and tumor-related variables were also compared. Statistical analyses included Kruskal–Wallis, Wilcoxon rank sum, and Fisher's exact tests. Two-sided P-values <0.05 were considered significant. Results: The overall complication rates, 13 (39.4%) of 33 cryoablation procedures versus eight (26.7%) of 30 radiofrequency ablation procedures and severe/fatal complication rates, two (6.1%) of 33 cryoablation procedures versus one (3.3%) of 30 radiofrequency ablation procedures, were not significantly different between the ablation groups (both P = 0.26). Severe complications included pneumothoraces requiring chest tube insertion during two cryoablation procedures. One death occurred within 90 days of a radiofrequency ablation procedure; all other complications were managed successfully. Conclusion: No significant difference was seen in the overall safety of image-guided percutaneous cryoablation and radiofrequency ablation in the treatment of hepatocellular carcinoma in patients with cirrhosis

Efficacy and Safety of Atrial Fibrillation Ablation Using Remote Magnetic Navigation

DEFF Research Database (Denmark)

Jin, Q I; Pehrson, Steen; Jacobsen, Peter Karl

2016-01-01

.0 minutes, PerAF, P = 0.17). The overall complication rate was 0.6%. One PAF patient experienced cardiac tamponade. AF repeat ablations by RMN significantly reduced the procedural and ablation times when compared with their first ablation times. CONCLUSIONS: AF ablation guided by RMN is safe as evidenced...

Cognitive and Neural Determinants of Response Strategy in the Dual-Solution Plus-Maze Task

Science.gov (United States)

De Leonibus, Elvira; Costantini, Vivian J. A.; Massaro, Antonio; Mandolesi, Georgia; Vanni, Valentina; Luvisetto, Siro; Pavone, Flaminia; Oliverio, Alberto; Mele, Andrea

2011-01-01

Response strategy in the dual-solution plus maze is regarded as a form of stimulus-response learning. In this study, by using an outcome devaluation procedure, we show that it can be based on both action-outcome and stimulus-response habit learning, depending on the amount of training that the animals receive. Furthermore, we show that…

Cryoballoon Ablation for Atrial Fibrillation

Directory of Open Access Journals (Sweden)

Jason G. Andrade, MD

2012-03-01

Full Text Available Focal point-by-point radiofrequency catheter ablation has shown considerable success in the treatment of paroxysmal atrial fibrillation. However, it is not without limitations. Recent clinical and preclinical studies have demonstrated that cryothermal ablation using a balloon catheter (Artic Front©, Medtronic CryoCath LP provides an effective alternative strategy to treating atrial fibrillation. The objective of this article is to review efficacy and safety data surrounding cryoballoon ablation for paroxysmal and persistent atrial fibrillation. In addition, a practical step-by-step approach to cryoballoon ablation is presented, while highlighting relevant literature regarding: 1 the rationale for adjunctive imaging, 2 selection of an appropriate cryoballoon size, 3 predictors of efficacy, 4 advanced trouble-shooting techniques, and 5 strategies to reduce procedural complications, such as phrenic nerve palsy.

Hippocampal activation during the recall of remote spatial memories in radial maze tasks.

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Schlesiger, Magdalene I; Cressey, John C; Boublil, Brittney; Koenig, Julie; Melvin, Neal R; Leutgeb, Jill K; Leutgeb, Stefan

2013-11-01

Temporally graded retrograde amnesia is observed in human patients with medial temporal lobe lesions as well as in animal models of medial temporal lobe lesions. A time-limited role for these structures in memory recall has also been suggested by the observation that the rodent hippocampus and entorhinal cortex are activated during the retrieval of recent but not of remote memories. One notable exception is the recall of remote memories for platform locations in the water maze, which requires an intact hippocampus and results in hippocampal activation irrespective of the age of the memory. These findings raise the question whether the hippocampus is always involved in the recall of spatial memories or, alternatively, whether it might be required for procedural computations in the water maze task, such as for calculating a path to a hidden platform. We performed spatial memory testing in radial maze tasks to distinguish between these possibilities. Radial maze tasks require a choice between spatial locations on a center platform and thus have a lesser requirement for navigation than the water maze. However, we used a behavioral design in the radial maze that retained other aspects of the standard water maze task, such as the use of multiple start locations and retention testing in a single trial. Using the immediate early gene c-fos as a marker for neuronal activation, we found that all hippocampal subregions were more activated during the recall of remote compared to recent spatial memories. In areas CA3 and CA1, activation during remote memory testing was higher than in rats that were merely reexposed to the testing environment after the same time interval. Conversely, Fos levels in the dentate gyrus were increased after retention testing to the extent that was also observed in the corresponding exposure control group. This pattern of hippocampal activation was also obtained in a second version of the task that only used a single start arm instead of multiple

Radiofrequency ablation of liver tumors (II): clinical application and outcomes.

Science.gov (United States)

Vanagas, Tomas; Gulbinas, Antanas; Pundzius, Juozas; Barauskas, Giedrius

2010-01-01

Radiofrequency ablation is one of the alternatives in the management of liver tumors, especially in patients who are not candidates for surgery. The aim of this article is to review applicability of radiofrequency ablation achieving complete tumor destruction, utility of imaging techniques for patients' follow-up, indications for local ablative procedures, procedure-associated morbidity and mortality, and long-term results in patients with different tumors. The success of local thermal ablation consists in creating adequate volumes of tissue destruction with adequate "clear margin," depending on improved delivery of radiofrequency energy and modulated tissue biophysiology. Different volumes of coagulation necrosis are achieved applying different types of electrodes, pulsing energy sources, utilizing sophisticated ablation schemes. Some additional methods are used to increase the overall deposition of energy through alterations in tissue electrical conductivity, to improve heat retention within the tissue, and to modulate tolerance of tumor tissue to hyperthermia. Contrast-enhanced computed tomography, magnetic resonance imaging, ultrasound or positron emission tomography are applied to control the effectiveness of radiofrequency ablation. The long-term results of radiofrequency ablation are controversial.

Virtual In-Silico Modeling Guided Catheter Ablation Predicts Effective Linear Ablation Lesion Set for Longstanding Persistent Atrial Fibrillation: Multicenter Prospective Randomized Study.

Science.gov (United States)

Shim, Jaemin; Hwang, Minki; Song, Jun-Seop; Lim, Byounghyun; Kim, Tae-Hoon; Joung, Boyoung; Kim, Sung-Hwan; Oh, Yong-Seog; Nam, Gi-Byung; On, Young Keun; Oh, Seil; Kim, Young-Hoon; Pak, Hui-Nam

2017-01-01

Objective: Radiofrequency catheter ablation for persistent atrial fibrillation (PeAF) still has a substantial recurrence rate. This study aims to investigate whether an AF ablation lesion set chosen using in-silico ablation (V-ABL) is clinically feasible and more effective than an empirically chosen ablation lesion set (Em-ABL) in patients with PeAF. Methods: We prospectively included 108 patients with antiarrhythmic drug-resistant PeAF (77.8% men, age 60.8 ± 9.9 years), and randomly assigned them to the V-ABL ( n = 53) and Em-ABL ( n = 55) groups. Five different in-silico ablation lesion sets [1 pulmonary vein isolation (PVI), 3 linear ablations, and 1 electrogram-guided ablation] were compared using heart-CT integrated AF modeling. We evaluated the feasibility, safety, and efficacy of V-ABL compared with that of Em-ABL. Results: The pre-procedural computing time for five different ablation strategies was 166 ± 11 min. In the Em-ABL group, the earliest terminating blinded in-silico lesion set matched with the Em-ABL lesion set in 21.8%. V-ABL was not inferior to Em-ABL in terms of procedure time ( p = 0.403), ablation time ( p = 0.510), and major complication rate ( p = 0.900). During 12.6 ± 3.8 months of follow-up, the clinical recurrence rate was 14.0% in the V-ABL group and 18.9% in the Em-ABL group ( p = 0.538). In Em-ABL group, clinical recurrence rate was significantly lower after PVI+posterior box+anterior linear ablation, which showed the most frequent termination during in-silico ablation (log-rank p = 0.027). Conclusions: V-ABL was feasible in clinical practice, not inferior to Em-ABL, and predicts the most effective ablation lesion set in patients who underwent PeAF ablation.

Unbiased classification of spatial strategies in the Barnes maze.

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Illouz, Tomer; Madar, Ravit; Clague, Charlotte; Griffioen, Kathleen J; Louzoun, Yoram; Okun, Eitan

2016-11-01

Spatial learning is one of the most widely studied cognitive domains in neuroscience. The Morris water maze and the Barnes maze are the most commonly used techniques to assess spatial learning and memory in rodents. Despite the fact that these tasks are well-validated paradigms for testing spatial learning abilities, manual categorization of performance into behavioral strategies is subject to individual interpretation, and thus to bias. We have previously described an unbiased machine-learning algorithm to classify spatial strategies in the Morris water maze. Here, we offer a support vector machine-based, automated, Barnes-maze unbiased strategy (BUNS) classification algorithm, as well as a cognitive score scale that can be used for memory acquisition, reversal training and probe trials. The BUNS algorithm can greatly benefit Barnes maze users as it provides a standardized method of strategy classification and cognitive scoring scale, which cannot be derived from typical Barnes maze data analysis. Freely available on the web at http://okunlab.wix.com/okunlab as a MATLAB application. eitan.okun@biu.ac.ilSupplementary information: Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Contemporary Tools and Techniques for Substrate Ablation of Ventricular Tachycardia in Structural Heart Disease.

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Hutchinson, Mathew D; Garza, Hyon-He K

2018-02-24

As we have witnessed in other arenas of catheter-based therapeutics, ventricular tachycardia (VT) ablation has become increasingly anatomical in its execution. Multi-modality imaging provides anatomical detail in substrate characterization, which is often complex in nonischemic cardiomyopathy patients. Patients with intramural, intraseptal, and epicardial substrates provide challenges in delivering effective ablation to the critical arrhythmia substrate due to the depth of origin or the presence of adjacent critical structures. Novel ablation techniques such as simultaneous unipolar or bipolar ablation can be useful to achieve greater lesion depth, though at the expense of increasing collateral damage. Disruptive technologies like stereotactic radioablation may provide a tailored approach to these complex patients while minimizing procedural risk. Substrate ablation is a cornerstone of the contemporary VT ablation procedure, and recent data suggest that it is as effective and more efficient that conventional activation guided ablation. A number of specific targets and techniques for substrate ablation have been described, and all have shown a fairly high success in achieving their acute procedural endpoint. Substrate ablation also provides a novel and reproducible procedural endpoint, which may add predictive value for VT recurrence beyond conventional programmed stimulation. Extrapolation of outcome data to nonischemic phenotypes requires caution given both the variability in substrate nonischemic distribution and the underrepresentation of these patients in previous trials.

Atrial Fibrillation Ablation in Systolic Dysfunction: Clinical and Echocardiographic Outcomes

Directory of Open Access Journals (Sweden)

Tasso Julio Lobo

2015-01-01

Full Text Available Background: Heart failure and atrial fibrillation (AF often coexist in a deleterious cycle. Objective: To evaluate the clinical and echocardiographic outcomes of patients with ventricular systolic dysfunction and AF treated with radiofrequency (RF ablation. Methods: Patients with ventricular systolic dysfunction [ejection fraction (EF <50%] and AF refractory to drug therapy underwent stepwise RF ablation in the same session with pulmonary vein isolation, ablation of AF nests and of residual atrial tachycardia, named "background tachycardia". Clinical (NYHA functional class and echocardiographic (EF, left atrial diameter data were compared (McNemar test and t test before and after ablation. Results: 31 patients (6 women, 25 men, aged 37 to 77 years (mean, 59.8±10.6, underwent RF ablation. The etiology was mainly idiopathic (19 p, 61%. During a mean follow-up of 20.3±17 months, 24 patients (77% were in sinus rhythm, 11 (35% being on amiodarone. Eight patients (26% underwent more than one procedure (6 underwent 2 procedures, and 2 underwent 3 procedures. Significant NYHA functional class improvement was observed (pre-ablation: 2.23±0.56; postablation: 1.13±0.35; p<0.0001. The echocardiographic outcome also showed significant ventricular function improvement (EF pre: 44.68%±6.02%, post: 59%±13.2%, p=0.0005 and a significant left atrial diameter reduction (pre: 46.61±7.3 mm; post: 43.59±6.6 mm; p=0.026. No major complications occurred. Conclusion: Our findings suggest that AF ablation in patients with ventricular systolic dysfunction is a safe and highly effective procedure. Arrhythmia control has a great impact on ventricular function recovery and functional class improvement.

Attitudes Towards Catheter Ablation for Atrial Fibrillation

DEFF Research Database (Denmark)

Vadmann, Henrik; Pedersen, Susanne S; Nielsen, Jens Cosedis

2015-01-01

BACKGROUND: Catheter ablation for atrial fibrillation (AF) is an important but expensive procedure that is the subject of some debate. Physicians´ attitudes towards catheter ablation may influence promotion and patient acceptance. This is the first study to examine the attitudes of Danish...... cardiologists towards catheter ablation for AF, using a nationwide survey. METHODS AND RESULTS: We developed a purpose-designed questionnaire to evaluate attitudes towards catheter ablation for AF that was sent to all Danish cardiologists (n = 401; response n = 272 (67.8%)). There was no association between...... attitudes towards ablation and the experience or age of the cardiologist with respect to patients with recurrent AF episodes with a duration of 7 days and/or need for cardioversion. The majority (69%) expected a recurrence of AF after catheter ablation in more than 30% of the cases...

Individualized laparoscopic B-ultrasound-guided microwave ablation for multifocal primary liver cancer.

Science.gov (United States)

Xu, Zhifeng; Yang, Zhangwei; Pan, Jianghua; Hu, Yiren

2018-03-01

Liver cancer is one of the most common malignancies of the digestive system. Minimally invasive ablation procedures have become one of the major means for treating unresectable multifocal liver cancer and have been extensively applied in primary and metastatic liver cancer treatment. Laparoscopic B-ultrasound-guided microwave ablation is an example of the progress made in this field. To analyze and summarize the results of and experience with laparoscopic B-ultrasound-guided microwave ablation for multifocal primary liver cancer; moreover, the ablation effects were compared between tumors of different sizes. Laparoscope-guided needle ablation was conducted on 84 lesions from 32 patients with primary liver cancer based on tumor size, quantity, and location. Moreover, the perioperative data, ablation effects according to tumor size, and long-term follow-up results were analyzed. Among the 84 nodules treated via microwave ablation, tumors measuring ≤ 3 cm demonstrated complete ablation upon imaging analysis conducted 1 month after surgery. Moreover, 5 of the tumors measuring > 3 cm demonstrated incomplete ablation. In these cases, a second procedure was performed, until imaging studies confirmed that complete ablation was achieved. Laparoscopic microwave ablation allows for precise puncture positioning, an effective ablation range, and safe and feasible surgery, which is especially suitable for liver tumors located in sites difficult to access.

Microwave Ablation of Lung Tumors Near the Heart: A Retrospective Review of Short-Term Procedural Safety in Ten Patients.

Science.gov (United States)

Maxwell, Aaron W P; Healey, Terrance T; Dupuy, Damian E

2017-09-01

To evaluate the rate of short-term complications associated with microwave ablation of lung tumors located near the heart. This HIPAA-compliant study was performed with a waiver for informed consent. Patients who underwent microwave ablation of lung tumors located 10 mm or less from the heart were identified by retrospective chart review. Both primary and metastatic tumors were included. Only tumors directly adjacent to one of the four cardiac chambers were included. All patients were treated in a single session using CT guidance with continuous electrocardiographic monitoring. Rates of new-onset arrhythmia and myocardial infarction (MI) within 90 days of the procedure were quantified, and evidence of cardiac or pericardiac injury was assessed for using post-ablation contrast-enhanced chest CT, electrocardiography (EKG), and-when available-echocardiography. Complications were graded using the Common Terminology Criteria for Adverse Events (CTCAE) system. Ten patients (four males, six females; mean age 73.1 ± 9.5 years) met all inclusion criteria. Mean tumor distance from the heart was 3 mm (range, 0-6 mm). New-onset arrhythmia was not observed during or following any of the microwave ablation treatments, and there were no documented 90-day MI events. CTCAE Grade 1 complications were observed by CT in eight patients, most commonly mild focal pericardial thickening. EKG and echocardiography were normal in all patients. No major complications (CTCAE Grade 3 or greater) were observed. Microwave ablation of lung tumors located 10 mm or less from the heart appears to have low associated short-term morbidity and may be appropriate in selected patients.

Organized Atrial Tachycardias after Atrial Fibrillation Ablation

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Castrejón-Castrejón, Sergio; Ortega, Marta; Pérez-Silva, Armando; Doiny, David; Estrada, Alejandro; Filgueiras, David; López-Sendón, José L.; Merino, José L.

2011-01-01

The efficacy of catheter-based ablation techniques to treat atrial fibrillation is limited not only by recurrences of this arrhythmia but also, and not less importantly, by new-onset organized atrial tachycardias. The incidence of such tachycardias depends on the type and duration of the baseline atrial fibrillation and specially on the ablation technique which was used during the index procedure. It has been repeatedly reported that the more extensive the left atrial surface ablated, the higher the incidence of organized atrial tachycardias. The exact origin of the pathologic substrate of these trachycardias is not fully understood and may result from the interaction between preexistent regions with abnormal electrical properties and the new ones resultant from radiofrequency delivery. From a clinical point of view these atrial tachycardias tend to remit after a variable time but in some cases are responsible for significant symptoms. A precise knowledge of the most frequent types of these arrhythmias, of their mechanisms and components is necessary for a thorough electrophysiologic characterization if a new ablation procedure is required. PMID:21941669

7-NI and ODQ Disturbs Memory in the Elevated Plus Maze, Morris Water Maze, and Radial Arm Maze Tests in Mice.

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Mutlu, Oguz; Akar, Furuzan; Celikyurt, Ipek Komsuoglu; Tanyeri, Pelin; Ulak, Guner; Erden, Faruk

2015-01-01

Nitric oxide (NO) is an atypical neurotransmitter that causes changes in cognition. Nitric oxide synthase (NOS) and guanylate cyclase (GC) inhibitors have been shown to exert some effects on cognition in previous studies; however, the findings have been controversial. This study was aimed at understanding the effects of an NOS inhibitor, 7-nitroindazole (7-NI), and a guanylate cyclase inhibitor, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), on spatial memory in modified elevated plus maze (mEPM), Morris water maze (MWM), and radial arm maze (RAM) tests. Male Balb-c mice were treated via intraperitoneal injections with 7-NI (15 mg/kg), ODQ (3, 10 mg/kg), L-arginine (100 mg/kg) + 7-NI (15 mg/kg), or physiological saline. ODQ (3 mg/kg) and 7-NI (15 mg/kg) significantly increased the second-day latency in the mEPM test. 7-NI (15 mg/kg) and ODQ (10 mg/kg) significantly increased the escape latency in second, third, and fourth sessions, decreased the time spent in the escape platform's quadrant, and increased the mean distance to the platform in the probe trial of the MWM test. ODQ (3, 10 mg/kg) and 7-NI (15 mg/kg) significantly increased the number of errors, whereas only 7-NI increased the latency in the RAM test. The administration of L-arginine (100 mg/kg) prior to 7-NI inverted the effects of 7-NI, which supports the role of NO on cognition. Our study shows that the NO/cGMP/GS pathway can regulate spatial memory in mice.

Characterisation of tissue shrinkage during microwave thermal ablation.

Science.gov (United States)

Farina, Laura; Weiss, Noam; Nissenbaum, Yitzhak; Cavagnaro, Marta; Lopresto, Vanni; Pinto, Rosanna; Tosoratti, Nevio; Amabile, Claudio; Cassarino, Simone; Goldberg, S Nahum

2014-11-01

The aim of this study was to characterise changes in tissue volume during image-guided microwave ablation in order to arrive at a more precise determination of the true ablation zone. The effect of power (20-80 W) and time (1-10 min) on microwave-induced tissue contraction was experimentally evaluated in various-sized cubes of ex vivo liver (10-40 mm ± 2 mm) and muscle (20 and 40 mm ± 2 mm) embedded in agar phantoms (N = 119). Post-ablation linear and volumetric dimensions of the tissue cubes were measured and compared with pre-ablation dimensions. Subsequently, the process of tissue contraction was investigated dynamically during the ablation procedure through real-time X-ray CT scanning. Overall, substantial shrinkage of 52-74% of initial tissue volume was noted. The shrinkage was non-uniform over time and space, with observed asymmetry favouring the radial (23-43 % range) over the longitudinal (21-29%) direction. Algorithmic relationships for the shrinkage as a function of time were demonstrated. Furthermore, the smallest cubes showed more substantial and faster contraction (28-40% after 1 min), with more considerable volumetric shrinkage (>10%) in muscle than in liver tissue. Additionally, CT imaging demonstrated initial expansion of the tissue volume, lasting in some cases up to 3 min during the microwave ablation procedure, prior to the contraction phenomenon. In addition to an asymmetric substantial shrinkage of the ablated tissue volume, an initial expansion phenomenon occurs during MW ablation. Thus, complex modifications of the tissue close to a radiating antenna will likely need to be taken into account for future methods of real-time ablation monitoring.

Use of asymmetric bidirectional catheters with different curvature radius for catheter ablation of cardiac arrhythmias.

Science.gov (United States)

Mantziari, Lilian; Suman-Horduna, Irina; Gujic, Marko; Jones, David G; Wong, Tom; Markides, Vias; Foran, John P; Ernst, Sabine

2013-06-01

The impact of recently introduced asymmetric bidirectional ablation catheters on procedural parameters and acute success rates of ablation procedures is unknown. We retrospectively analyzed data regarding ablations using a novel bidirectional catheter in a tertiary cardiac center and compared these in 1:5 ratio with a control group of procedures matched for age, gender, operator, and ablation type. A total of 50 cases and 250 controls of median age 60 (50-68) years were studied. Structural heart disease was equally prevalent in both groups (39%) while history of previous ablations was more common in the study arm (54% vs 30%, P = 0.001). Most of the ablation cases were for atrial fibrillation (46%), followed by atrial tachycardia (28%), supraventricular tachycardia (12%), and ventricular tachycardia (14%). Median procedure duration was 128 (52-147) minutes with the bidirectional, versus 143 (105-200) minutes with the conventional catheter (P = 0.232), and median fluoroscopy time was 17 (10-34) minutes versus 23 (12-39) minutes, respectively (P = 0.988). There was a trend toward a lower procedure duration for the atrial tachycardia ablations, 89 (52-147) minutes versus 130 (100-210) minutes, P = 0.064. The procedure was successfully completed in 96% of the bidirectional versus 84% of the control cases (P = 0.151). A negative correlation was observed between the relative fluoroscopy duration and the case number (r = -0.312, P = 0.028), reflecting the learning curve for the bidirectional catheter. The introduction of the bidirectional catheter resulted in no prolongation of procedure parameters and similar success rates, while there was a trend toward a lower procedure duration for atrial tachycardia ablations. ©2013, The Authors. Journal compilation ©2013 Wiley Periodicals, Inc.

Ultrasound-guided percutaneous thermal ablation of hepatocellular carcinoma using microwave and radiofrequency ablation

Energy Technology Data Exchange (ETDEWEB)

Xu, H.-X.; Xie, X.-Y.; Lu, M.-D. E-mail: lumd@21cn.com; Chen, J.-W.; Yin, X.-Y.; Xu, Z.-F.; Liu, G.-J

2004-01-01

AIM: To investigate the therapeutic efficacy of thermal ablation for treatment of hepatocellular carcinoma (HCC) using microwave and radiofrequency (RF) energy application. MATERIALS AND METHODS: A total of 190 nodules in 97 patients (84 male, 13 female; mean age 53.4 years, range 24-74 years) with HCC were treated with microwave or RF ablation in the last 4 years. The applicators were introduced into the tumours under conscious analgesic sedation by intravenous administration of fentanyl citrate and droperidol and local anaesthesia in both thermal ablation procedures. The patients were then followed up with contrast-enhanced computed tomography (CT) to evaluate treatment response. Survival was analysed using the Kaplan-Meier method. RESULTS: Complete ablation was obtained in 92.6% (176/190) nodules. The complete ablation rates were 94.6% (106/112) in microwave ablation and 89.7% (70/78) in RF ablation. The complete ablation rates in tumours{<=}2.0, 2.1-3.9 and {>=}4.0 cm were 93.1, 93.8 and 86.4%, respectively. Local recurrence was found in 9.5% nodules and the rates in tumours{<=}2.0, 2.1-3.9 and {>=}4.0 cm in diameter were 3.4, 9.9 and 31.8%, respectively. In the follow-up period, 7.1% nodules ablated by microwave and 12.8% by RF presented local recurrence. The 1, 2 and 3-year distant recurrence-free survivals were 47.2, 34.9 and 31.0%, respectively. Estimated mean survival was 32 months, and 1, 2 and 3-year cumulative survivals were 75.6, 58.5, and 50.0%, respectively. One and 2 years survivals of Child-Pugh class A, B and C patients were 83.8 and 70.4%, 78.2 and 53.2%, 36.3 and 27.3%, respectively. CONCLUSION: Thermal ablation therapy by means of microwave and RF energy application is an effective and safe therapeutic technique for hepatocellular carcinoma. Large tumours can be completely ablated, but have a significantly higher risk of local recurrence at follow-up.

Ultrasound-guided percutaneous thermal ablation of hepatocellular carcinoma using microwave and radiofrequency ablation

International Nuclear Information System (INIS)

Xu, H.-X.; Xie, X.-Y.; Lu, M.-D.; Chen, J.-W.; Yin, X.-Y.; Xu, Z.-F.; Liu, G.-J.

2004-01-01

AIM: To investigate the therapeutic efficacy of thermal ablation for treatment of hepatocellular carcinoma (HCC) using microwave and radiofrequency (RF) energy application. MATERIALS AND METHODS: A total of 190 nodules in 97 patients (84 male, 13 female; mean age 53.4 years, range 24-74 years) with HCC were treated with microwave or RF ablation in the last 4 years. The applicators were introduced into the tumours under conscious analgesic sedation by intravenous administration of fentanyl citrate and droperidol and local anaesthesia in both thermal ablation procedures. The patients were then followed up with contrast-enhanced computed tomography (CT) to evaluate treatment response. Survival was analysed using the Kaplan-Meier method. RESULTS: Complete ablation was obtained in 92.6% (176/190) nodules. The complete ablation rates were 94.6% (106/112) in microwave ablation and 89.7% (70/78) in RF ablation. The complete ablation rates in tumours≤2.0, 2.1-3.9 and ≥4.0 cm were 93.1, 93.8 and 86.4%, respectively. Local recurrence was found in 9.5% nodules and the rates in tumours≤2.0, 2.1-3.9 and ≥4.0 cm in diameter were 3.4, 9.9 and 31.8%, respectively. In the follow-up period, 7.1% nodules ablated by microwave and 12.8% by RF presented local recurrence. The 1, 2 and 3-year distant recurrence-free survivals were 47.2, 34.9 and 31.0%, respectively. Estimated mean survival was 32 months, and 1, 2 and 3-year cumulative survivals were 75.6, 58.5, and 50.0%, respectively. One and 2 years survivals of Child-Pugh class A, B and C patients were 83.8 and 70.4%, 78.2 and 53.2%, 36.3 and 27.3%, respectively. CONCLUSION: Thermal ablation therapy by means of microwave and RF energy application is an effective and safe therapeutic technique for hepatocellular carcinoma. Large tumours can be completely ablated, but have a significantly higher risk of local recurrence at follow-up

Atrial Fibrillation Ablation Guided by a Novel Nonfluoroscopic Navigation System.

Science.gov (United States)

Ballesteros, Gabriel; Ramos, Pablo; Neglia, Renzo; Menéndez, Diego; García-Bolao, Ignacio

2017-09-01

Rhythmia is a new nonfluoroscopic navigation system that is able to create high-density electroanatomic maps. The aim of this study was to describe the acute outcomes of atrial fibrillation (AF) ablation guided by this system, to analyze the volume provided by its electroanatomic map, and to describe its ability to locate pulmonary vein (PV) reconnection gaps in redo procedures. This observational study included 62 patients who underwent AF ablation with Rhythmia compared with a retrospective cohort who underwent AF ablation with a conventional nonfluoroscopic navigation system (Ensite Velocity). The number of surface electrograms per map was significantly higher in Rhythmia procedures (12 125 ± 2826 vs 133 ± 21 with Velocity; P < .001), with no significant differences in the total procedure time. The Orion catheter was placed for mapping in 99.5% of PV (95.61% in the control group with a conventional circular mapping catheter; P = .04). There were no significant differences in the percentage of PV isolation between the 2 groups. In redo procedures, an ablation gap could be identified on the activation map in 67% of the reconnected PV (40% in the control group; P = .042). The measured left atrial volume was lower than that calculated by computed tomography (109.3 v 15.2 and 129.9 ± 13.2 mL, respectively; P < .001). There were no significant differences in the number of complications. The Rhythmia system is effective for AF ablation procedures, with procedure times and safety profiles similar to conventional nonfluoroscopic navigation systems. In redo procedures, it appears to be more effective in identifying reconnected PV conduction gaps. Copyright © 2016 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

Bilateral cornual abscess after endometrial ablation following Essure sterilization.

NARCIS (Netherlands)

Jansen, N.E.; Vleugels, M.P.; Kluivers, K.B.; Vierhout, M.E.

2007-01-01

Endometrial ablation is used extensively to treat dysfunctional bleeding. Since the introduction of Essure tubal sterilization, this permanent contraception method has been widely used. Both endometrial ablation and Essure sterilization are procedures reported to have only a few complications. We

Assessment of anxiety in open field and elevated plus maze using infrared thermography.

Science.gov (United States)

Lecorps, Benjamin; Rödel, Heiko G; Féron, Christophe

2016-04-01

Due to their direct inaccessibility, affective states are classically assessed by gathering concomitant physiological and behavioral measures. Although such a dual approach to assess emotional states is frequently used in different species including humans, the invasiveness of procedures for physiological recordings particularly in smaller-sized animals strongly restricts their application. We used infrared thermography, a non-invasive method, to assess physiological arousal during open field and elevated plus maze tests in mice. By measuring changes in surface temperature indicative of the animals' emotional response, we aimed to improve the inherently limited and still controversial information provided by behavioral parameters commonly used in these tests. Our results showed significant and consistent thermal responses during both tests, in accordance with classical physiological responses occurring in stressful situations. Besides, we found correlations between these thermal responses and the occurrence of anxiety-related behaviors. Furthermore, initial temperatures measured at the start of each procedure (open field, elevated plus maze), which can be interpreted as a measure of the animals' initial physiological arousal, predicted the levels of activity and of anxiety-related behaviors displayed during the tests. Our results stress the strong link between physiological correlates of emotions and behaviors expressed during unconditioned fear tests. Copyright © 2016 Elsevier Inc. All rights reserved.

Microwave Tissue Ablation: Biophysics, Technology and Applications

Science.gov (United States)

2010-01-01

Microwave ablation is an emerging treatment option for many cancers, cardiac arrhythmias and other medical conditions. During treatment, microwaves are applied directly to tissues to produce rapid temperature elevations sufficient to produce immediate coagulative necrosis. The engineering design criteria for each application differ, with individual consideration for factors such as desired ablation zone size, treatment duration, and procedural invasiveness. Recent technological developments in applicator cooling, power control and system optimization for specific applications promise to increase the utilization of microwave ablation in the future. This article will review the basic biophysics of microwave tissue heating, provide an overview of the design and operation of current equipment, and outline areas for future research for microwave ablation. PMID:21175404

Perioral Rejuvenation With Ablative Erbium Resurfacing.

Science.gov (United States)

Cohen, Joel L

2015-11-01

Since the introduction of the scanning full-field erbium laser, misconceptions regarding ablative erbium resurfacing have resulted in its being largely overshadowed by ablative fractional resurfacing. This case report illustrates the appropriateness of full-field erbium ablation for perioral resurfacing. A patient with profoundly severe perioral photodamage etched-in lines underwent full-field ablative perioral resurfacing with an erbium laser (Contour TRL, Sciton Inc., Palo Alto, CA) that allows separate control of ablation and coagulation. The pre-procedure consultations included evaluation of the severity of etched-in lines, and discussion of patient goals, expectations, and appropriate treatment options, as well as a review of patient photos and post-treatment care required. The author generally avoids full-field erbium ablation in patients with Fitzpatrick type IV and above. For each of 2 treatment sessions (separated by approximately 4 months), the patient received (12 cc plain 2% lidodaine) sulcus blocks before undergoing 4 passes with the erbium laser at 150 μ ablation, no coagulation, and then some very focal 30 μ ablation to areas of residual lines still visualized through the pinpoint bleeding. Similarly, full-field ablative resurfacing can be very reliable for significant wrinkles and creping in the lower eyelid skin--where often a single treatment of 80 μ ablation, 50 μ coagulation can lead to a nice improvement. Standardized digital imaging revealed significant improvement in deeply etched rhytides without significant adverse events. For appropriately selected patients requiring perioral (or periorbital) rejuvenation, full-field ablative erbium resurfacing is safe, efficacious and merits consideration.

Microwave ablation of renal tumors: state of the art and development trends.

Science.gov (United States)

Floridi, Chiara; De Bernardi, Irene; Fontana, Federico; Muollo, Alessandra; Ierardi, Anna Maria; Agostini, Andrea; Fonio, Paolo; Squillaci, Ettore; Brunese, Luca; Fugazzola, Carlo; Carrafiello, Gianpaolo

2014-07-01

In the last decades an increased incidence of new renal tumor cases has been for clinically localized, small tumors elderly patients, with medical comorbidities whom the risk of surgical complications may pose a greater risk of death than that due to the tumor itself. In these patients, unsuitable for surgical approach, thermal ablation represents a valid alternative to traditional surgery. Thermal ablation is a less invasive, less morbid treatment option thanks to reduced blood loss, lower incidence of complications during the procedure and a less long convalescence. At present, the most widely used thermal ablative techniques are cryoablation, radiofrequency ablation and microwave ablation (MWA). MWA offers many benefits of other ablation techniques and offers several other advantages: higher intratumoral temperatures, larger tumor ablation volumes, faster ablation times, the ability to use multiple applicators simultaneously, optimal heating of cystic masses and tumors close to the vessels and less procedural pain. This review aims to provide the reader with an overview about the state of the art of microwave ablation for renal tumors and to cast a glance on the new development trends of this technique.

7-NI and ODQ Disturbs Memory in the Elevated plus Maze, Morris Water Maze, and Radial Arm Maze Tests in Mice

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Oguz Mutlu

2015-01-01

Full Text Available Nitric oxide (NO is an atypical neurotransmitter that causes changes in cognition. Nitric oxide synthase (NOS and guanylate cyclase (GC inhibitors have been shown to exert some effects on cognition in previous studies; however, the findings have been controversial. This study was aimed at understanding the effects of an NOS inhibitor, 7-nitroindazole (7-NI, and a guanylate cyclase inhibitor, 1 H -[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, on spatial memory in modified elevated plus maze (mEPM, Morris water maze (MWM, and radial arm maze (RAM tests. Male Balb-c mice were treated via intraperitoneal injections with 7-NI (15 mg/kg, ODQ (3, 10 mg/kg, L-arginine (100 mg/kg + 7-NI (15 mg/kg, or physiological saline. ODQ (3 mg/kg and 7-NI (15 mg/kg significantly increased the second-day latency in the mEPM test. 7-NI (15 mg/kg and ODQ (10 mg/kg significantly increased the escape latency in second, third, and fourth sessions, decreased the time spent in the escape platform's quadrant, and increased the mean distance to the platform in the probe trial of the MWM test. ODQ (3, 10 mg/kg and 7-NI (15 mg/kg significantly increased the number of errors, whereas only 7-NI increased the latency in the RAM test. The administration of L-arginine (100 mg/kg prior to 7-NI inverted the effects of 7-NI, which supports the role of NO on cognition. Our study shows that the NO/cGMP/GS pathway can regulate spatial memory in mice.

A comparison of the calculation methods of the maze shielding dose

International Nuclear Information System (INIS)

Li Wenqian; Li Junli; Li Pengyu; Tao Yinghua

2009-01-01

This paper gives a theoretical calculating method for the dose rate of the maze of the low-energy accelerators or high-energy accelerators, based on the NCRP report Nos.49, 51 and 151. The multi-legged maze of the Miyun CT workshop of the NUCTECH Company Limited and the arc maze of the radiation laboratory of the Academy of Military Medical Sciences were calculated using this method. The calculating results were compared with the MCNP simulating results and the measured results. For the commonly estimation of the maze dose rate, as long as the parameters chosen properly, this method can give a conservative result, and save time from simulation. It's hoped that this work could offer a reference for the maze design and the dose estimation method in the aftertime. (authors)

Percutaneous thermal ablation of renal neoplasms

International Nuclear Information System (INIS)

Tacke, J.; Mahnken, A.H.; Guenther, R.W.

2005-01-01

Due to modern examination techniques such as multidetector computed tomography and high-field magnetic resonance imaging, the detection rate of renal neoplasms is continually increasing. Even though tumors exceeding 4 cm in diameter rarely metastasize, all renal lesions that are possible neoplasms should be treated. Traditional treatment techniques include radical nephrectomy or nephron-sparing resection, which are increasingly performed laparoscopically. Modern thermal ablation techniques such as hyperthermal techniques like radiofrequency ablation RFA, laser induced thermal ablation LITT, focused ultrasound FUS and microwave therapy MW, as well as hypothermal techniques (cryotherapy) may be a useful treatment option for patients who are unfit for or refuse surgical resection. Cryotherapy is the oldest and best known thermal ablation technique and can be performed laparoscopically or percutaneously. Since subzero temperatures have no antistyptic effect, additional maneuvers must be performed to control bleeding. Percutaneous cryotherapy of renal tumors is a new and interesting method, but experience with it is still limited. Radiofrequency ablation is the most frequently used method. Modern probe design allows volumes between 2 and 5 cm in diameter to be ablated. Due to hyperthermal tract ablation, the procedure is deemed to be safe and has a low complication rate. Although there are no randomized comparative studies to open resection, the preliminary results for renal RFA are promising and show RFA to be superior to other thermal ablation techniques. Clinical success rates are over 90% for both, cryo- and radiofrequency ablation. Whereas laser induced thermal therapy is established in hepatic ablation, experience is minimal with respect to renal application. For lesions of more than 2 cm in diameter, additional cooling catheters are required. MR thermometry offers temperature control during ablation. Microwave ablation is characterized by small ablation volumes

CT-guided radiofrequency tumor ablation in children

International Nuclear Information System (INIS)

Botsa, Evanthia; Poulou, Loukia S.; Koundouraki, Antonia; Thanos, Loukas; Koutsogiannis, Ioannis; Ziakas, Panayiotis D.; Alexopoulou, Efthimia

2014-01-01

Image-guided radiofrequency ablation is a well-accepted technique of interventional oncology in adults. To evaluate the efficacy and safety of CT-guided radiofrequency ablation as a minimally invasive treatment for metastatic neoplasms in children. A total of 15 radiofrequency ablation sessions were performed in 12 children and young adults (median age 9.5; range 5-18 years) with metastatic malignancies. Seven children and young adults had secondary hepatic lesions, three had pulmonary and two had bone lesions. Radiofrequency ablation was performed under conscious sedation. The median lesion size was 1.7 cm (range 1.3-2.8 cm). The median time for ablation was 8 min (range 7-10 min). Radiofrequency procedures were technically successful in all tumors. Postablation imaging immediately after, and 1 month and 3 months after radiofrequency ablation showed total necrosis in all patients. At 6-month follow-up, three patients (all with lesion size >2 cm) had local recurrence and underwent a second radiofrequency ablation session. At 2-year follow-up no patient had recurrence of the treated tumor. Post-ablation syndrome occurred in four children. No major complication occurred. CT-guided radiofrequency tumor ablation was safe and efficient for palliative treatment in our cohort of patients. (orig.)

CT-guided radiofrequency tumor ablation in children

Energy Technology Data Exchange (ETDEWEB)

Botsa, Evanthia [National and Kapodistrian University of Athens, First Pediatric Clinic, Agia Sofia Children' s Hospital, Athens (Greece); Poulou, Loukia S.; Koundouraki, Antonia; Thanos, Loukas [Sotiria General Hospital for Chest Diseases, Department of Medical Imaging and Interventional Radiology, Athens (Greece); Koutsogiannis, Ioannis [General Military Hospital NIMTS, Department of Medical Imaging, Athens (Greece); Ziakas, Panayiotis D. [Warren Alpert Medical School of Brown University Rhode Island Hospital, Division of Infectious Diseases, Providence, RI (United States); Alexopoulou, Efthimia [Attikon University Hospital, Second Department of Radiology, Athens University School of Medicine, Athens (Greece)

2014-11-15

Image-guided radiofrequency ablation is a well-accepted technique of interventional oncology in adults. To evaluate the efficacy and safety of CT-guided radiofrequency ablation as a minimally invasive treatment for metastatic neoplasms in children. A total of 15 radiofrequency ablation sessions were performed in 12 children and young adults (median age 9.5; range 5-18 years) with metastatic malignancies. Seven children and young adults had secondary hepatic lesions, three had pulmonary and two had bone lesions. Radiofrequency ablation was performed under conscious sedation. The median lesion size was 1.7 cm (range 1.3-2.8 cm). The median time for ablation was 8 min (range 7-10 min). Radiofrequency procedures were technically successful in all tumors. Postablation imaging immediately after, and 1 month and 3 months after radiofrequency ablation showed total necrosis in all patients. At 6-month follow-up, three patients (all with lesion size >2 cm) had local recurrence and underwent a second radiofrequency ablation session. At 2-year follow-up no patient had recurrence of the treated tumor. Post-ablation syndrome occurred in four children. No major complication occurred. CT-guided radiofrequency tumor ablation was safe and efficient for palliative treatment in our cohort of patients. (orig.)

Innovative approach for in-vivo ablation validation on multimodal images

Science.gov (United States)

Shahin, O.; Karagkounis, G.; Carnegie, D.; Schlaefer, A.; Boctor, E.

2014-03-01

Radiofrequency ablation (RFA) is an important therapeutic procedure for small hepatic tumors. To make sure that the target tumor is effectively treated, RFA monitoring is essential. While several imaging modalities can observe the ablation procedure, it is not clear how ablated lesions on the images correspond to actual necroses. This uncertainty contributes to the high local recurrence rates (up to 55%) after radiofrequency ablative therapy. This study investigates a novel approach to correlate images of ablated lesions with actual necroses. We mapped both intraoperative images of the lesion and a slice through the actual necrosis in a common reference frame. An electromagnetic tracking system was used to accurately match lesion slices from different imaging modalities. To minimize the liver deformation effect, the tracking reference frame was defined inside the tissue by anchoring an electromagnetic sensor adjacent to the lesion. A validation test was performed using a phantom and proved that the end-to-end accuracy of the approach was within 2mm. In an in-vivo experiment, intraoperative magnetic resonance imaging (MRI) and ultrasound (US) ablation images were correlated to gross and histopathology. The results indicate that the proposed method can accurately correlate invivo ablations on different modalities. Ultimately, this will improve the interpretation of the ablation monitoring and reduce the recurrence rates associated with RFA.

Genetic ablation of the GluK4 kainate receptor subunit causes anxiolytic and antidepressant-like behavior in mice.

Science.gov (United States)

Catches, Justin S; Xu, Jian; Contractor, Anis

2012-03-17

There is a clear link between dysregulation of glutamatergic signaling and mood disorders. Genetic variants in the glutamate receptor gene GRIK4, which encodes the kainate receptor subunit GluK4, alter the susceptibility for depression, bipolar disorder and schizophrenia. Here we demonstrate that Grik4(-/-) mice have reduced anxiety and an antidepressant-like phenotype. In the elevated zero-maze, a test for anxiety and risk taking behavior, Grik4(-/-) mice spent significantly more time exploring the open areas of the maze. In anxiogenic tests of marble-burying and novelty-induced suppression of feeding, anxiety-like behavior was consistently reduced in knockout animals. In the forced swim test, a test of learned helplessness that is used to determine depression-like behavior, knockout mice demonstrated significantly less immobility suggesting that Grik4 ablation has an antidepressant-like effect. Finally, in the sucrose preference test, a test for anhedonia in rodents, Grik4(-/-) mice demonstrated increased sucrose preference. Expression of the GluK4 receptor subunit in the forebrain is restricted to the CA3 region of the hippocampus and dentate gyrus regions where KARs are known to modulate synaptic plasticity. We tested whether Grik4 ablation had effects on mossy fiber (MF) plasticity and found there to be a significant impairment in LTP likely through a loss of KAR modulation of excitability of the presynaptic MF axons. These studies demonstrate a clear anxiolytic and antidepressant phenotype associated with ablation of Grik4 and a parallel disruption in hippocampal plasticity, providing support for the importance of this receptor subunit in mood disorders. Copyright © 2011 Elsevier B.V. All rights reserved.

Ultrasound-guided radiofrequency ablation of thyroid gland: a preliminary study in dogs

International Nuclear Information System (INIS)

Choi, Ji Won; Yoo, Seung Min; Kwak, Seo Hyun

2005-01-01

The purpose of this study was to evaluate the possibility of using radiofrequency ablation as the treatment modality for the benign or malignant thyroid nodules in humans. Therefore, we examined the results of using radiofrequency ablation on the thyroid glands in dogs, in respect of the extent of the ablated tissue and the complications. Five dogs (10 lobes of the thyroid glands) were included in this study. US-guided radiofrequency ablation was undertaken with a 10 mm, uncovered 17 gauge cool-tip needle. The power and duration was 20 wattage and 1 minute in five thyroid lobes (group 1) and 20 wattage and 2 minutes in another 5 thyroid lobes (group 2). The ultrasound scans and the pre-and post-enhancement CT scans were undertaken before and immediately after the procedures, and at 24 hours, 72 hours and 1 week later. The US and CT findings of the ablated tissue and complications were evaluated. Blood sampling was done at the pre-procedure time and 1 week later for evaluating the functional status of the thyroid gland. Laryngoscopy was done at the pre-procedure and post-procedure times, and at 24 hours, 72 hours and 1 week later for the evaluation of any recurrent laryngeal nerve palsy. The echo pattern of the ablated thyroid gland at immediately after the radiofrequency ablation appeared as poorly marginated and hyperechoic. On the US obtained 24 hours after radiofrequency ablation, the echo pattern of the ablated thyroid gland was hypoechoic. The maximum diameters after RFA were 9.4 ρ 0.5 mm in group I and 11.4 ρ 0.5 mm in group II. The pre-enhanced CT scan taken at immediately after the radiofrequency ablation showed ill defined hypodense areas in the ablated thyroid gland. Differentiation between the normal and abnormal portions of the thyroid gland was difficult on the contrast enhanced CT scan. Complications induced by radiofrequency ablation were one recurrent laryngeal nerve palsy, two perforations of esophagus and five thickenings of the esophageal wall

Ultrasound-guided radiofrequency ablation of thyroid gland: a preliminary study in dogs

Energy Technology Data Exchange (ETDEWEB)

Choi, Ji Won; Yoo, Seung Min [College of Medicine, Chungang University, Seoul, (Korea, Republic of); Kwak, Seo Hyun [Seoul Veterans Hospital, Seoul (Korea, Republic of)

2005-07-15

The purpose of this study was to evaluate the possibility of using radiofrequency ablation as the treatment modality for the benign or malignant thyroid nodules in humans. Therefore, we examined the results of using radiofrequency ablation on the thyroid glands in dogs, in respect of the extent of the ablated tissue and the complications. Five dogs (10 lobes of the thyroid glands) were included in this study. US-guided radiofrequency ablation was undertaken with a 10 mm, uncovered 17 gauge cool-tip needle. The power and duration was 20 wattage and 1 minute in five thyroid lobes (group 1) and 20 wattage and 2 minutes in another 5 thyroid lobes (group 2). The ultrasound scans and the pre-and post-enhancement CT scans were undertaken before and immediately after the procedures, and at 24 hours, 72 hours and 1 week later. The US and CT findings of the ablated tissue and complications were evaluated. Blood sampling was done at the pre-procedure time and 1 week later for evaluating the functional status of the thyroid gland. Laryngoscopy was done at the pre-procedure and post-procedure times, and at 24 hours, 72 hours and 1 week later for the evaluation of any recurrent laryngeal nerve palsy. The echo pattern of the ablated thyroid gland at immediately after the radiofrequency ablation appeared as poorly marginated and hyperechoic. On the US obtained 24 hours after radiofrequency ablation, the echo pattern of the ablated thyroid gland was hypoechoic. The maximum diameters after RFA were 9.4 {rho} 0.5 mm in group I and 11.4 {rho} 0.5 mm in group II. The pre-enhanced CT scan taken at immediately after the radiofrequency ablation showed ill defined hypodense areas in the ablated thyroid gland. Differentiation between the normal and abnormal portions of the thyroid gland was difficult on the contrast enhanced CT scan. Complications induced by radiofrequency ablation were one recurrent laryngeal nerve palsy, two perforations of esophagus and five thickenings of the esophageal

ROLE OF RADIOFREQUENCY ABLATION IN ADENOMA SEBACEUM

Directory of Open Access Journals (Sweden)

Ch. Madh

2016-03-01

Full Text Available Adenoma sebaceum, pathognomonic of tuberous sclerosis, are tiny angiofibromas which commonly occur over central part of face. Recurrence after treatment is common and hence a need for inexpensive, safe and efficient treatment is required. Radiofrequency ablation is a safe and an economical procedure and has been known to cause less scarring with good aesthetic results compared to other ablative methods such as electrocautery.

Radiofrequency Ablation of Liver Tumors

Science.gov (United States)

... have had a surgical procedure in which the liver bile duct has been connected to a loop of bowel are at much greater risk of developing a liver abscess after ablation. Women should always inform their ...

Elevated mazes as animal models of anxiety: effects of serotonergic agents

Directory of Open Access Journals (Sweden)

Simone H. Pinheiro

2007-03-01

Full Text Available This article reviews reported results about the effects of drugs that act upon the serotonergic neurotransmission measured in three elevated mazes that are animal models of anxiety. A bibliographic search has been performed in MEDLINE using different combinations of the key words X-maze, plus-maze, T-maze, serotonin and 5-HT, present in the title and/or the abstract, with no time limit. From the obtained abstracts, several publications were excluded on the basis of the following criteria: review articles that did not report original results, species other than the rat, intracerebral drug administration alone, genetically manipulated rats, and animals having any kind of experimental pathology. The reported results indicate that the effect of drugs on the inhibitory avoidance task performed in the elevated T-maze and on the spatio temporal indexes of anxiety measured in the X and plus mazes correlate with their effect in patients diagnosed with generalized anxiety disorder. In contrast, the drug effects on the one-way escape task in the elevated T-maze predict the drug response of panic disorder patients. Overall, the drug effects assessed with the avoidance task in the T-maze are more consistent than those measured through the anxiety indexes of the X and plus mazes. Therefore, the elevated T-maze is a promising animal model of generalized anxiety and panic disorder.No presente artigo, revisamos resultados publicados relatando efeitos de drogas que atuam na neurotransmissão serotonérgica medidos em três labirintos elevados, que são modelos animais de ansiedade. Realizamos uma busca bibliográfica no MEDLINE, usando diferentes combinações das palavras-chave: X-maze, plus-maze, T-maze, serotonin e 5-HT, presentes no título ou no resumo, sem limite de tempo. Dos resumos obtidos, vários foram excluídos com base nos seguintes critérios: artigos de revisão que não continham resultados originais, espécies diferentes do rato, apenas inje

Osteoid Osteoma: Experience with Laser- and Radiofrequency-Induced Ablation

International Nuclear Information System (INIS)

Gebauer, Bernhard; Tunn, Per-Ulf; Gaffke, Gunnar; Melcher, Ingo; Felix, Roland; Stroszczynski, Christian

2006-01-01

The purpose of this study was to analyze the clinical outcome of osteoid osteoma treated by thermal ablation after drill opening. A total of 17 patients and 20 procedures were included. All patients had typical clinical features (age, pain) and a typical radiograph showing a nidus. In 5 cases, additional histological specimens were acquired. After drill opening of the osteoid osteoma nidus, 12 thermal ablations were induced by laser interstitial thermal therapy (LITT) (9F Power-Laser-Set; Somatex, Germany) and 8 ablations by radiofrequency ablation (RFA) (RITA; StarBurst, USA). Initial clinical success with pain relief has been achieved in all patients after the first ablation. Three patients had an osteoid osteoma recurrence after 3, 9, and 10 months and were successfully re-treated by thermal ablation. No major complication and one minor complication (sensible defect) were recorded. Thermal ablation is a safe and minimally invasive therapy option for osteoid osteoma. Although the groups are too small for a comparative analysis, we determined no difference between laser- and radiofrequency-induced ablation in clinical outcome after ablation

Innovative techniques for image-guided ablation of benign thyroid nodules: Combined ethanol and radiofrequency ablation

Energy Technology Data Exchange (ETDEWEB)

Park, Hye Sun; Baek, Jung Hwan; Choi, Young Jun; Lee, Jeong Hyun [Dept. of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of)

2017-06-15

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.

A novel elevated plus-maze procedure to avoid the one-trial tolerance problem

Directory of Open Access Journals (Sweden)

Peggy eSchneider

2011-07-01

Full Text Available The elevated plus-maze (EPM test is one of the most commonly used behavioural assays to evaluate anxiety-related behaviour in rodents. It is a rather economic test which usually uses a short (5 min protocol and does not require conditioning of the animals. The critical measure for anxiety is the time spent in the open arms of the maze. A confounding problem of the EPM is the so called one-trial tolerance (OTT, characterised by a marked decrease of open arm exploration in spite of treatment with anxiolytic acting benzodiazepines upon re-exposure to the EPM. This consistent finding is often raised as an evidence for the inappropriateness to re-test rodents in the EPM. However, a reliable re-test paradigm would broaden the usability and effectiveness of this test.Therefore, we tested how a prolongation of the inter-trial interval to 28 days (instead of the usual 24 hours, and an additional change of the testing room would affect the open arm time and other behaviours on the EPM. In two experiments, drug naive Wistar rats were exposed to the EPM on trial 1, and treated intraperitoneally with either vehicle or midazolam (0.25 mg/kg 30 min before trial 2. Then, trial 2 (28 days after trial 1 was carried out in either the same testing room (Exp. 1 or a second unfamiliar room (Exp. 2.Twenty-eight days after trial 1 the open arm time of the rats in the vehicle treated control rats of both experimental groups was comparable to that of the first trial, independent of the testing room. Most importantly, we found that the treatment with the benzodiazepine midazolam had a significantly anxiolytic-like (i.e. increase of open arm time effect in trial 2 only when conducted in the previously unfamiliar testing room (Exp. 2. We suggest that in order to reliably re-test the EPM and to prevent confounding effects due to the OTT, an inter-trial interval of 28 days and a change in testing rooms reinstates anxiolytic-like actions of benzodiazepines

Laser ablation in analytical chemistry - A review

Energy Technology Data Exchange (ETDEWEB)

Russo, Richard E.; Mao, Xianglei; Liu, Haichen; Gonzalez, Jhanis; Mao, Samuel S.

2001-10-10

Laser ablation is becoming a dominant technology for direct solid sampling in analytical chemistry. Laser ablation refers to the process in which an intense burst of energy delivered by a short laser pulse is used to sample (remove a portion of) a material. The advantages of laser ablation chemical analysis include direct characterization of solids, no chemical procedures for dissolution, reduced risk of contamination or sample loss, analysis of very small samples not separable for solution analysis, and determination of spatial distributions of elemental composition. This review describes recent research to understand and utilize laser ablation for direct solid sampling, with emphasis on sample introduction to an inductively coupled plasma (ICP). Current research related to contemporary experimental systems, calibration and optimization, and fractionation is discussed, with a summary of applications in several areas.

Survival after Radiofrequency Ablation in 122 Patients with Inoperable Colorectal Lung Metastases

Energy Technology Data Exchange (ETDEWEB)

Gillams, Alice, E-mail: alliesorting@gmail.com [The London Clinic, Radiology Department (United Kingdom); Khan, Zahid [Countess of Chester Hospital (United Kingdom); Osborn, Peter [Queen Alexandra Hospital (United Kingdom); Lees, William [University College London Medical School (United Kingdom)

2013-06-15

Purpose. To analyze the factors associated with favorable survival in patients with inoperable colorectal lung metastases treated with percutaneous image-guided radiofrequency ablation. Methods. Between 2002 and 2011, a total of 398 metastases were ablated in 122 patients (87 male, median age 68 years, range 29-90 years) at 256 procedures. Percutaneous CT-guided cool-tip radiofrequency ablation was performed under sedation/general anesthesia. Maximum tumor size, number of tumors ablated, number of procedures, concurrent/prior liver ablation, previous liver or lung resection, systemic chemotherapy, disease-free interval from primary resection to lung metastasis, and survival from first ablation were recorded prospectively. Kaplan-Meier analysis was performed, and factors were compared by log rank test. Results. The initial number of metastases ablated was 2.3 (range 1-8); the total number was 3.3 (range 1-15). The maximum tumor diameter was 1.7 (range 0.5-4) cm, and the number of procedures was 2 (range 1-10). The major complication rate was 3.9 %. Overall median and 3-year survival rate were 41 months and 57 %. Survival was better in patients with smaller tumors-a median of 51 months, with 3-year survival of 64 % for tumors 2 cm or smaller versus 31 months and 44 % for tumors 2.1-4 cm (p = 0.08). The number of metastases ablated and whether the tumors were unilateral or bilateral did not affect survival. The presence of treated liver metastases, systemic chemotherapy, or prior lung resection did not affect survival. Conclusion. Three-year survival of 57 % in patients with inoperable colorectal lung metastases is better than would be expected with chemotherapy alone. Patients with inoperable but small-volume colorectal lung metastases should be referred for ablation.

Catheter ablation of epicardial ventricular tachycardia

Directory of Open Access Journals (Sweden)

Takumi Yamada, MD, PhD

2014-08-01

Full Text Available Ventricular tachycardias (VTs can usually be treated by endocardial catheter ablation. However, some VTs can arise from the epicardial surface, and their substrate can be altered only by epicardial catheter ablation. There are two approaches to epicardial catheter ablation: transvenous and transthoracic. The transvenous approach through the coronary venous system (CVS has been commonly used because it is easily accessible. However, this approach may be limited by the distribution of the CVS and insufficient radiofrequency energy delivery. Transthoracic epicardial catheter ablation has been developed to overcome these limitations of the transvenous approach. It is a useful supplemental or even preferred strategy to eliminate epicardial VTs in the electrophysiology laboratory. This technique has been applied for scar-related VTs secondary to often non-ischemic cardiomyopathy and sometimes ischemic cardiomyopathy, and idiopathic VTs as the epicardial substrates of these VTs have become increasingly recognized. When endocardial ablation and epicardial ablation through the CVS are unsuccessful, transthoracic epicardial ablation should be the next option. Intrapericardial access is usually obtained through a subxiphoidal pericardial puncture. This approach might not be possible in patients with pericardial adhesions caused by prior cardiac surgery or pericarditis. In such cases, a hybrid procedure involving surgical access with a subxiphoid pericardial window and a limited anterior or lateral thoracotomy might be a feasible and safe method of performing an epicardial catheter ablation in the electrophysiology laboratory. Potential complications associated with this technique include bleeding and collateral damage to the coronary arteries and phrenic nerve. Although the risk of these complications is low, electrophysiologists who attempt epicardial catheter ablation should know the complications associated with this technique, how to minimize their

Amazeobot : The construction of a maze mapping robot

OpenAIRE

REBECCA, WIKSTRÖM; MARTIN, SJÖGREN

2016-01-01

For the purpose of exploring how a computer can navigate through a maze, this project examines how a robot’s surroundings can be interpreted, mapped and navigated through, by applying common maze solving algorithms. The execution of the project involves infrared sensors used to interpret a controlled environment, consisting of a twodimensional board with paths. Movement and navigation decisions will be made possible by two DCmotorized wheels mounted on a platform, two simple computers and two...

Percutaneous radiofrequency ablation for benign nodules of the thyroid gland

International Nuclear Information System (INIS)

Baek, Jung Hwan; Jeong, Hyun Jo; Kim, Yoon Suk; Kwak, Min Sook; Chang, Sun Hee; Rhim, Hyun Chul

2005-01-01

We wanted to evaluate the efficacy and safety of using ultrasound guided percutaneous radiofrequency ablation for the benign nodules of the thyroid gland. We studied 148 patients with benign thyroid nodules (200 total nodules) that were confirmed histopathologically, and we performed ultrasound guided radiofrequency ablation. The radiofrequency ablation was done 1 to 5 times per one nodule, and follow-up ultrasonography was performed one to nineteen months after the ablation procedures. The physical changes and the decrease of volume of the nodules were evaluated, and the complications related to radiofrequency ablation were observed. The mean initial nodule volume was 0.01-95.61 ml (mean; 6.83 ± SD of 10.63 ml) and the nodule volume after radiofrequency ablation was decreased to 0.00-46.56 ml (mean; 1.83 ± SD of 4.69 ml). The mean volume reduction rate was 73.2%. Reduction of more than 50% was noted in 90% of all cases. For 180 nodules (90%), the decrease was 50% or more, in 20 nodules (10%), the decrease was 49% or less. On gray-scale ultrasonogram obtained after ablation, the echogenicity of the nodules changed to darker, and on the doppler-sonogram, the vascular flow within the nodules disappeared in all cases. Most patients complained pain during or right after the procedure, but the pain was transient and subsided after medication. Two patients developed hoarseness that was improved in 1 week and 2 months, respectively. Sonoguided percutaneous radiofrequency ablation can be one of the treatments for benign nodules of the thyroid gland

[Comparison of ablation of left-sided accessory pathway by atrial septal and retrograde arterial approach].

Science.gov (United States)

Zhu, J G; Bao, Z Y; Gu, X

2017-03-07

Objective: To compare the advantages and disadvantages of radiofrequency ablation of left-sided accessory pathways by via atrial septal approach with retrograde through aortic approach. Methods: A total of 184 patients of left-side accessory pathways were treated in Taizhou People's Hospital and the Subei People's Hospital from March 2012 to August 2015.A total of 103 cases were treated by aortic retrograde approach as through arterial group, 81 cases were treated by punctured atrial septal to left atrial for mapping and ablation as through atrial septal group.Comparison of ablation procedure time, total and pathways of different parts(subgroup) at instant success and relapse rates, safety (serious complications), and statistics other complications in operation and postoperative. Results: Through arterial group and through atrial septal group were no significant difference ( P >0.05) in the ablation procedure time((25±18 ) vs (22±15)min ), instant success(98.1% vs 97.5%) and relapse rates(1.0% vs 1.2%), security(1 vs 0 case). There was no statistical difference in septal part subgroups (all P >0.05) in the ablation procedure time((22±18)vs (25±19)min), instant success(91.7% vs 89.9 %) and relapse rates(0 vs 11.1%); posterior wall subgroup had no statistical difference in the ablation procedure time((18±15)vs (16±12)min), instant success(100% vs 100 %) and relapse rates(0 vs 0)(all P >0.05); side wall subgroup had no statistical difference in the ablation procedure time((29±20)vs (21±18) min), instant success (98.3% vs 98.1%)and relapse rates(1.7% vs 0%)(all P >0.05). Conclusion: Ablation of left-sided accessory pathways by transseptal approach and transaortic approach has no statistical difference in the procedure time, instant success and relapse rates, security.In a particular case, there is a certain complementarity between the two methods.

Behavioral consequences of predator stress in the rat elevated T-maze.

Science.gov (United States)

Bulos, Erika Mondin; Pobbe, Roger Luis Henschel; Zangrossi, Helio

2015-07-01

Analyses of the behavioral reactions of rodents to predators have greatly contributed to the understanding of defense-related human psychopathologies such as anxiety and panic.We here investigated the behavioral consequences of exposing male Wistar rats to a live cat using the elevated T-maze test of anxiety. This test allows the measurement of two defensive responses: inhibitory avoidance and escape, which in terms of pathology have been associated with generalized anxiety and panic disorders, respectively. For comparative reasons, the effects of exposure to the cat were also assessed in the elevated plus-maze. The results showed that a 5-min exposure to the cat selectively facilitated inhibitory avoidance acquisition, an anxiogenic effect, without affecting escape expression in the elevated T-maze. This was seen immediately but not 30 min after contact with the predator. This short-lived anxiogenic effect was also detected in the elevated plus-maze. Previous administration of the benzodiazepine anxiolytic diazepam (2 mg/kg) decreased the immediate avoidance response to the predator and the neophobic reaction to a dummy cat used as a control stimulus. The drug also impaired inhibitory avoidance acquisition in the elevated T-maze, indicating an anxiolytic effect, without affecting escape performance. The results indicate that the state of anxiety evoked during contact with the predator generalizes to both elevated plus- and T-mazes, impacting on defensive responses associated with generalized anxiety disorder.

Ablative thermal protection systems

International Nuclear Information System (INIS)

Vaniman, J.; Fisher, R.; Wojciechowski, C.; Dean, W.

1983-01-01

The procedures used to establish the TPS (thermal protection system) design of the SRB (solid rocket booster) element of the Space Shuttle vehicle are discussed. A final evaluation of the adequacy of this design will be made from data obtained from the first five Shuttle flights. Temperature sensors installed at selected locations on the SRB structure covered by the TPS give information as a function of time throughout the flight. Anomalies are to be investigated and computer design thermal models adjusted if required. In addition, the actual TPS ablator material loss is to be measured after each flight and compared with analytically determined losses. The analytical methods of predicting ablator performance are surveyed. 5 references

Effect of Radiofrequency Endometrial Ablation on Dysmenorrhea.

Science.gov (United States)

Wyatt, Sabrina N; Banahan, Taylor; Tang, Ying; Nadendla, Kavita; Szychowski, Jeff M; Jenkins, Todd R

To examine rates of dysmenorrhea after radiofrequency endometrial ablation in patients with and without known dysmenorrhea symptoms prior to the procedure in a diverse population. Retrospective cohort study (Canadian Task Force classification II-2). Academic gynecology practice. A total of 307 women underwent endometrial ablation between 2007 and 2013 at our institution. Patients who had preoperative and postoperative pain symptom assessments as well as a description of pain timing recorded were included in our analysis. Exclusion criteria were age dysmenorrhea was evaluated. Demographic information and other outcome variables were used to evaluate factors associated with resolution of dysmenorrhea. A total of 307 patients who underwent radiofrequency endometrial ablation were identified. After exclusions, 296 charts were examined, and 144 patients met our enrollment criteria. The mean age of the study cohort was 45.4 ± 6.2 years; 57 patients (40%) were African American, 16 (11%) had a body mass index (BMI) > 40, and 41 (29%) were of normal weight. Preoperative dysmenorrhea was reported by 100 patients (69%); 48 of these patients (48%) experienced resolution of symptoms postoperatively. Only 3 of the 44 patients (7%) without preoperative dysmenorrhea reported new-onset dysmenorrhea postoperatively. Significantly fewer patients had dysmenorrhea after compared to before radiofrequency ablation (55 of 144 [38%] vs 100 of 144 [69%]; p dysmenorrhea after ablation was associated with reduction in bleeding volume (p = .048) but not with a reduction in frequency of bleeding (p = .12). Approximately one-half of women who undergo radiofrequency endometrial ablation to treat heavy menstrual bleeding who also have preoperative dysmenorrhea exhibit documented pain resolution after the procedure. Resolution of dysmenorrhea is more likely if menstrual flow volume is decreased postprocedure. Copyright © 2016 AAGL. Published by Elsevier Inc. All rights reserved.

Effects of endocardial microwave energy ablation

Directory of Open Access Journals (Sweden)

Vicente Climent

2005-07-01

Full Text Available Until recently the treatment of atrial fibrillation (AF consisted primarily of palliation, mostly in the form of pharmacological intervention. However because of recent advances in nonpharmacologic therapies, the current expectation of patients and referring physicians is that AF will be cured, rather than palliated. In recent years there has been a rapid expansion in the availability and variety of energy sources and devices for ablation. One of these energies, microwave, has been applied clinically only in the last few years, and may be a promising technique that is potentially capable of treating a wide range of ventricular and supraventricular arrhythmias. The purpose of this study was to review microwave energy ablation in surgical treatment of AF with special interest in histology and ultrastructure of lesions produced by this endocardial ablation procedure.

Skin pre-ablation and laser assisted microjet injection for deep tissue penetration.

Science.gov (United States)

Jang, Hun-Jae; Yeo, Seonggu; Yoh, Jack J

2017-04-01

For conventional needless injection, there still remain many unresolved issues such as the potential for cross-contamination, poor reliability of targeted delivery dose, and significantly painstaking procedures. As an alternative, the use of microjets generated with Er:YAG laser for delivering small doses with controlled penetration depths has been reported. In this study, a new system with two stages is evaluated for effective transdermal drug delivery. First, the skin is pre-ablated to eliminate the hard outer layer and second, laser-driven microjet penetrates the relatively weaker and freshly exposed epidermis. Each stage of operation shares a single Er:YAG laser that is suitable for skin ablation as well as for the generation of a microjet. In this study, pig skin is selected for quantification of the injection depth based on the two-stage procedure, namely pre-ablation and microjet injection. The three types of pre-ablation devised here consists of bulk ablation, fractional ablation, and fractional-rotational ablation. The number of laser pulses are 12, 18, and 24 for each ablation type. For fractional-rotational ablation, the fractional beams are rotated by 11.25° at each pulse. The drug permeation in the skin is evaluated using tissue marking dyes. The depth of penetration is quantified by a cross sectional view of the single spot injections. Multi-spot injections are also carried out to control the dose and spread of the drug. The benefits of a pre-ablation procedure prior to the actual microjet injection to the penetration is verified. The four possible combinations of injection are (a) microjet only; (b) bulk ablation and microjet injection; (c) fractional ablation and microjet injection; and (d) fractional-rotational ablation and microjet injection. Accordingly, the total depth increases with injection time for all cases. In particular, the total depth of penetration attained via fractional pre-ablation increased by 8 ∼ 11% and that of fractional

Three-dimensional atrial wall thickness maps to inform catheter ablation procedures for atrial fibrillation.

Science.gov (United States)

Bishop, Martin; Rajani, Ronak; Plank, Gernot; Gaddum, Nicholas; Carr-White, Gerry; Wright, Matt; O'Neill, Mark; Niederer, Steven

2016-03-01

Transmural lesion formation is critical to success in atrial fibrillation ablation and is dependent on left atrial wall thickness (LAWT). Pre- and peri-procedural planning may benefit from LAWT measurements. To calculate the LAWT, the Laplace equation was solved over a finite element mesh of the left atrium derived from the segmented computed tomographic angiography (CTA) dataset. Local LAWT was then calculated from the length of field lines derived from the Laplace solution that spanned the wall from the endocardium or epicardium. The method was validated on an atrium phantom and retrospectively applied to 10 patients who underwent routine coronary CTA for standard clinical indications at our institute. The Laplace wall thickness algorithm was validated on the left atrium phantom. Wall thickness measurements had errors of atrial wall thickness measurements were performed on 10 patients. Successful comprehensive LAWT maps were generated in all patients from the coronary CTA images. Mean LAWT measurements ranged from 0.6 to 1.0 mm and showed significant inter and intra patient variability. Left atrial wall thickness can be measured robustly and efficiently across the whole left atrium using a solution of the Laplace equation over a finite element mesh of the left atrium. Further studies are indicated to determine whether the integration of LAWT maps into pre-existing 3D anatomical mapping systems may provide important anatomical information for guiding radiofrequency ablation. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

Pellet ablation and ablation model development

International Nuclear Information System (INIS)

Houlberg, W.A.

1989-01-01

A broad survey of pellet ablation is given, based primarily on information presented at this meeting. The implications of various experimental observations for ablation theory are derived from qualitative arguments of the physics involved. The major elements of a more complete ablation theory are then outlined in terms of these observations. This is followed by a few suggestions on improving the connections between theory and experimental results through examination of ablation data. Although this is a rather aggressive undertaking for such a brief (and undoubtedly incomplete) assessment, some of the discussion may help us advance the understanding of pellet ablation. 17 refs

Penentuan Nilai Motorik Halus Anak Dengan Game Magic Maze Menggunakan Metode Mamdani

OpenAIRE

Fadly, Muhammad

2015-01-01

Motor development is a very important factor in the development of the whole child. fine motor skills are very important because it affects the other terms of learning in early childhood. Therefore, it made the game Magic Maze to assess motor skills early childhood. Game Magic Maze in this study using Mamdani method in determining the values to a child's fine motor skills. Maze game will be made on the PC. 081402045

An image-guided system for optimized volumetric treatment planning and execution for radiofrequency ablation of liver tumors

Energy Technology Data Exchange (ETDEWEB)

Banovac, F.; Popa, T.; Cheng, P.; Cleary, K. [Computer Aided Interventions and Medical Robotics (CAIMR), Imaging Science and Information Systems (ISIS) Center, Georgetown Univ. Medical Center, Washington, DC (United States); Abeledo, H.; Campos-Nanez, E. [Dept. of Engineering Management and System Engineering, George Washington Univ., Washington, DC (United States); Wood, B.J. [Diagnostic Radiology Dept., NIH Clinical Center, Bethesda, MD (United States)

2007-06-15

Radiofrequency ablation of liver tumors is becoming an increasingly popular option for the treatment of cancer. However, the procedure has several technical challenges, mostly associated with precision targeting of the tumor and ensuring complete ablation coverage. In this paper we describe an image-guided system that we are developing for improved visualization and probe placement during these procedures. The system will include a pre-procedure optimization module and an intra-procedure guidance component. The system concept is explained and some preliminary results are given. While this system is designed for radiofrequency ablation of liver tumors, the methods are applicable to other organs and treatment methods. (orig.)

Thermal Ablation of Lung Tissue: In Vivo Experimental Comparison of Microwave and Radiofrequency

International Nuclear Information System (INIS)

Crocetti, Laura; Bozzi, Elena; Faviana, Pinuccia; Cioni, Dania; Della Pina, Clotilde; Sbrana, Alberto; Fontanini, Gabriella; Lencioni, Riccardo

2010-01-01

This study was designed to compare feasibility, safety, and effectiveness of microwave (MW) ablation versus radiofrequency (RF) ablation of lung tissue in a rabbit model. Twenty New Zealand White rabbits were submitted to MW (n = 10, group A) or RF ablation (n = 10, group B). The procedures were performed with a prototype MW ablation device with a 1.6-cm radiating section antenna (Valleylab MW Ablation System) and with a 2-cm exposed-tip RF electrode (Cool-tip RF Ablation System). At immediate computed tomography increase in density, maximum diameters (D1-D3) of ablation zones were measured and ablation volume was calculated. Histopathologic assessment was performed 3 and 7 days after the procedure. Technical success was achieved in nine of 10 rabbits in each group. One death occurred in group B. Complications included pneumothorax (group A, n = 4; group B, n = 4), abscess (group A, n = 1; group B, n = 1), and thoracic wall burn (group A, n = 4). No significant differences were demonstrated in attenuation increase (P = 0.73), dimensions (P = 0.28, 0.86, 0.06, respectively, comparing D1-D3) and volume (P = 0.17). At histopathology, ablation zones were similar, with septal necrosis, edema, hemorrhage, and peripheral lymphocytic infiltrate. Complete thrombosis of more than 90% of vessels up to 2 mm in diameter was depicted at the periphery of the ablation zone in group A specimens. In group B specimens, complete thrombosis was depicted in 20% of vessels. Feasibility and safety of MW and RF ablation are similar in a lung rabbit model. MW ablation produces a greater damage to peripheral small vessels inducing thrombosis.

Cone-beam computed tomography fusion and navigation for real-time positron emission tomography-guided biopsies and ablations: a feasibility study.

Science.gov (United States)

Abi-Jaoudeh, Nadine; Mielekamp, Peter; Noordhoek, Niels; Venkatesan, Aradhana M; Millo, Corina; Radaelli, Alessandro; Carelsen, Bart; Wood, Bradford J

2012-06-01

To describe a novel technique for multimodality positron emission tomography (PET) fusion-guided interventions that combines cone-beam computed tomography (CT) with PET/CT before the procedure. Subjects were selected among patients scheduled for a biopsy or ablation procedure. The lesions were not visible with conventional imaging methods or did not have uniform uptake on PET. Clinical success was defined by adequate histopathologic specimens for molecular profiling or diagnosis and by lack of enhancement on follow-up imaging for ablation procedures. Time to target (time elapsed between the completion of the initial cone-beam CT scan and first tissue sample or treatment), total procedure time (time from the moment the patient was on the table until the patient was off the table), and number of times the needle was repositioned were recorded. Seven patients underwent eight procedures (two ablations and six biopsies). Registration and procedures were completed successfully in all cases. Clinical success was achieved in all biopsy procedures and in one of the two ablation procedures. The needle was repositioned once in one biopsy procedure only. On average, the time to target was 38 minutes (range 13-54 min). Total procedure time was 95 minutes (range 51-240 min, which includes composite ablation). On average, fluoroscopy time was 2.5 minutes (range 1.3-6.2 min). An integrated cone-beam CT software platform can enable PET-guided biopsies and ablation procedures without the need for additional specialized hardware. Copyright © 2012 SIR. Published by Elsevier Inc. All rights reserved.

The creativity maze

DEFF Research Database (Denmark)

Bourgeois-Bougrine, Samira; Glaveanu, Vlad Petre; Botella, Marion

2014-01-01

The present article aims to address a current gap in our understanding of creativity in screenplay writing by focusing on the cognitive, conative, affective, and environmental factors that come into play at different stages in the creative process. It reports a study employing in-depth interviews...... and or treatment), and, finally, intense periods of writing and rewriting the script. These 3 stages, and, in particular, the multiple and concrete decisions to be taken within each one of them, support a vision of the creative process in this domain metaphorically conceptualized as crossing a maze. Creators...

Walkable self-overlapping virtual reality maze and map visualization demo

DEFF Research Database (Denmark)

Serubugo, Sule; Skantarova, Denisa; Evers, Nicolaj

2017-01-01

This paper describes our demonstration of a walkable self-overlapping maze and its corresponding map to facilitate asymmetric collaboration for room-scale virtual reality setups in public places.......This paper describes our demonstration of a walkable self-overlapping maze and its corresponding map to facilitate asymmetric collaboration for room-scale virtual reality setups in public places....

Percutaneous Microwave Ablation of Renal Angiomyolipomas

Energy Technology Data Exchange (ETDEWEB)

Cristescu, Mircea, E-mail: mcristescu@uwhealth.org [University of Wisconsin, Department of Radiology (United States); Abel, E. Jason, E-mail: abel@urology.wisc.edu [University of Wisconsin, Department of Urology (United States); Wells, Shane, E-mail: swells@uwhealth.org; Ziemlewicz, Timothy J., E-mail: tziemlewicz@uwhealth.org [University of Wisconsin, Department of Radiology (United States); Hedican, Sean P., E-mail: hedican@surgery.wisc.edu [University of Wisconsin, Department of Urology (United States); Lubner, Megan G., E-mail: mlubner@uwhealth.org; Hinshaw, J. Louis, E-mail: jhinshaw@uwhealth.org; Brace, Christopher L., E-mail: cbrace@uwhealth.org; Lee, Fred T., E-mail: flee@uwhealth.org [University of Wisconsin, Department of Radiology (United States)

2016-03-15

PurposeTo evaluate the safety and efficacy of US-guided percutaneous microwave (MW) ablation in the treatment of renal angiomyolipoma (AML).Materials and MethodsFrom January 2011 to April 2014, seven patients (5 females and 2 males; mean age 51.4) with 11 renal AMLs (9 sporadic type and 2 tuberous sclerosis associated) with a mean size of 3.4 ± 0.7 cm (range 2.4–4.9 cm) were treated with high-powered, gas-cooled percutaneous MW ablation under US guidance. Tumoral diameter, volume, and CT/MR enhancement were measured on pre-treatment, immediate post-ablation, and delayed post-ablation imaging. Clinical symptoms and creatinine were assessed on follow-up visits.ResultsAll ablations were technically successful and no major complications were encountered. Mean ablation parameters were ablation power of 65 W (range 60–70 W), using 456 mL of hydrodissection fluid per patient, over 4.7 min (range 3–8 min). Immediate post-ablation imaging demonstrated mean tumor diameter and volume decreases of 1.8 % (3.4–3.3 cm) and 1.7 % (27.5–26.3 cm{sup 3}), respectively. Delayed imaging follow-up obtained at a mean interval of 23.1 months (median 17.6; range 9–47) demonstrated mean tumor diameter and volume decreases of 29 % (3.4–2.4 cm) and 47 % (27.5–12.1 cm{sup 3}), respectively. Tumoral enhancement decreased on immediate post-procedure and delayed imaging by CT/MR parameters, indicating decreased tumor vascularity. No patients required additional intervention and no patients experienced spontaneous bleeding post-ablation.ConclusionOur early experience with high-powered, gas-cooled percutaneous MW ablation demonstrates it to be a safe and effective modality to devascularize and decrease the size of renal AMLs.

Catheter Ablation of Focal Atrial Tachycardia Using Remote Magnetic Navigation

DEFF Research Database (Denmark)

Liu, Xiao-Yu; Jacobsen, Peter Karl; Pehrson, Steen

2018-01-01

, a total of 56 atrial foci were found. Acute success of the primary ablation was obtained in 52 patients (98%). Mean procedure duration was 109 ± 35 min, ablation duration was 401 sec (interquartile range [IQR], 332 sec), and fluoroscopy time was 5.0 min (IQR, 3.0 min). After a mean follow-up of 31 ± 18...

Actual role of radiofrequency ablation of liver metastases

Energy Technology Data Exchange (ETDEWEB)

Pereira, Philippe L. [Eberhard-Karls-University of Tuebingen, Department of Diagnostic Radiology, Tuebingen (Germany)

2007-08-15

The liver is, second only to lymph nodes, the most common site for metastatic disease irrespective of the primary tumour. More than 50% of all patients with malignant diseases will develop liver metastases with a significant morbidity and mortality. Although the surgical resection leads to an improved survival in patients with colorectal metastases, only approximately 20% of patients are eligible for surgery. Thermal ablation and especially radiofrequency ablation emerge as an important additional therapy modality for the treatment of liver metastases. RF ablation shows a benefit in life expectancy and may lead in a selected patient group to cure. Percutaneous RF ablation appears safer (versus cryotherapy), easier (versus laser), and more effective (versus ethanol instillation and transarterial chemoembolisation) compared with other minimally invasive procedures. RF ablation can be performed by a percutaneous, laparoscopical or laparotomic approach, and may be potentially combined with chemotherapy and surgery. At present ideal candidates have tumours with a maximum diameter less than 3.5 cm. An untreatable primary tumour or a systemic disease represents contraindications for performing local therapies. Permanent technical improvements of thermal ablation devices and a better integration of thermal ablation in the overall patient care may lead to prognosis improvement in patients with liver metastases. (orig.)

Actual role of radiofrequency ablation of liver metastases

International Nuclear Information System (INIS)

Pereira, Philippe L.

2007-01-01

The liver is, second only to lymph nodes, the most common site for metastatic disease irrespective of the primary tumour. More than 50% of all patients with malignant diseases will develop liver metastases with a significant morbidity and mortality. Although the surgical resection leads to an improved survival in patients with colorectal metastases, only approximately 20% of patients are eligible for surgery. Thermal ablation and especially radiofrequency ablation emerge as an important additional therapy modality for the treatment of liver metastases. RF ablation shows a benefit in life expectancy and may lead in a selected patient group to cure. Percutaneous RF ablation appears safer (versus cryotherapy), easier (versus laser), and more effective (versus ethanol instillation and transarterial chemoembolisation) compared with other minimally invasive procedures. RF ablation can be performed by a percutaneous, laparoscopical or laparotomic approach, and may be potentially combined with chemotherapy and surgery. At present ideal candidates have tumours with a maximum diameter less than 3.5 cm. An untreatable primary tumour or a systemic disease represents contraindications for performing local therapies. Permanent technical improvements of thermal ablation devices and a better integration of thermal ablation in the overall patient care may lead to prognosis improvement in patients with liver metastases. (orig.)

[Left versus bi-atrial radiofrequency ablation in the treatment of atrial fibrillation].

Science.gov (United States)

Wang, Jian-Gang; Meng, Xu; Li, Hui

2008-11-25

To evaluate the effectiveness of radiofrequency modified maze operation for the treatment of atrial fibrillation (AF) and compare the results of the left versus bi-atrial procedures. 305 patients of organic heart disease combined with AF, 117 males and 188 females, aged (53 +/- 10), that underwent cardiac valve operation (n = 293) and/or coronary artery bypass graft surgery (n = 14), received concomitant atrial fibrillation, bi-atrial (n = 160) or left atrial (n = 145) with a mean duration of (36 +/- 43) months. Follow-up was conducted for (28 +/- 5) (3 - 42) months. Thirteen patients (4.3%) died postoperatively: 7 died of multisystem and organ failure, 3 of low cardiac output, 1 of rupture of left ventricle, 1 of arrhythmia, and 1 of sudden death. During the follow-up, 1 patient died of heart failure, 1 of encephalorrhagia and 1 of unknown reason in the bi-atrial group. At the end of the procedure 223 patients (73.1%) had sinus rhythm, with a sinus rhythm rate of 66.9% (107/160) in the bi-atrial group, significant lower than that in the left atrial group (80.0%, 116/145, P bi-atrial group was 80.0%, not significantly different from that of the left atrial group (81.9%, P > 0.05). The Kaplan-Meier survival analysis showed there was no significant difference in the AF rhythm rate between these 2 groups (P = 0.33). Logistic regression analysis showed that the left atrial diameter of >/= 80 mm was an independent predictor of AF recurrence. Both the left and bi-atrial procedures are successful in terms of restoring sinus rhythm. Left atrial ablation in severe cases and where the incision of right atrium is not needed is a reasonable choice.

Tissue Necrosis Monitoring for HIFU Ablation with T1 Contrast MRI Imaging

Science.gov (United States)

Hwang, San-Chao; Yao, Ching; Kuo, Ih-Yuan; Tsai, Wei-Cheng; Chang, Hsu

2011-09-01

In MR-guided HIFU ablation, MTC (Magnetization Transfer Contrast) or perfusion imaging is usually used after ablation to evaluate the ablated area based on the thermally induced necrosis contrast. In our MR-guided HIFU ablation study, a T1 contrast MRI scan sequence has been used to distinguish between necrotic and non-necrotic tissue. The ablation of porcine meat in-vitro and in-vivo pig leg muscle show that the necrotic area of T1 contrast MRI image coincides with the photographs of sliced specimen. The sequence is considerably easier to apply than MTC or perfusion imaging, while giving good necrosis contrast. In addition, no injection of contrast agent is needed, allowing multiple scans to be applied throughout the entire ablation procedure.

Estimating Effective Dose from Phantom Dose Measurements in Atrial Fibrillation Ablation Procedures and Comparison of MOSFET and TLD Detectors in a Small Animal Dosimetry Setting

Science.gov (United States)

Anderson-Evans, Colin David

Two different studies will be presented in this work. The first involves the calculation of effective dose from a phantom study which simulates an atrial fibrillation (AF) ablation procedure. The second involves the validation of metal-oxide semiconducting field effect transistors (MOSFET) for small animal dosimetry applications as well as improved characterization of the animal irradiators on Duke University's campus. Atrial Fibrillation is an ever increasing health risk in the United States. The most common type of cardiac arrhythmia, AF is associated with increased mortality and ischemic cerebrovascular events. Managing AF can include, among other treatments, an interventional procedure called catheter ablation. The procedure involves the use of biplane fluoroscopy during which a patient can be exposed to radiation for as much as two hours or more. The deleterious effects of radiation become a concern when dealing with long fluoroscopy times, and because the AF ablation procedure is elective, it makes relating the risks of radiation ever more essential. This study hopes to quantify the risk through the derivation of dose conversion coefficients (DCCs) from the dose-area product (DAP) with the intent that DCCs can be used to provide estimates of effective dose (ED) for typical AF ablation procedures. A bi-plane fluoroscopic and angiographic system was used for the simulated AF ablation procedures. For acquisition of organ dose measurements, 20 diagnostic MOSFET detectors were placed at selected organs in a male anthropomorphic phantom, and these detectors were attached to 4 bias supplies to obtain organ dose readings. The DAP was recorded from the system console and independently validated with an ionization chamber and radiochromic film. Bi-plane fluoroscopy was performed on the phantom for 10 minutes to acquire the dose rate for each organ, and the average clinical procedure time was multiplied by each organ dose rate to obtain individual organ doses. The

Percutaneous laser ablation of benign and malignant thyroid nodules.

Science.gov (United States)

Papini, Enrico; Bizzarri, Giancarlo; Pacella, Claudio M

2008-10-01

Percutaneous image-guided procedures, largely based on thermal ablation, are at present under investigation for achieving a nonsurgical targeted cytoreduction in benign and malignant thyroid lesions. In several uncontrolled clinical trials and in two randomized clinical trials, laser ablation has demonstrated a good efficacy and safety for the shrinkage of benign cold thyroid nodules. In hyperfunctioning nodules, laser ablation induced a nearly 50% volume reduction with a variable frequency of normalization of thyroid-stimulating hormone levels. Laser ablation has been tested for the palliative treatment of poorly differentiated thyroid carcinomas, local recurrences or distant metastases. Laser ablation therapy is indicated for the shrinkage of benign cold nodules in patients with local pressure symptoms who are at high surgical risk. The treatment should be performed only by well trained operators and after a careful cytological evaluation. Laser ablation does not seem to be consistently effective in the long-term control of hyperfunctioning thyroid nodules and is not an alternative treatment to 131I therapy. Laser ablation may be considered for the cytoreduction of tumor tissue prior to external radiation therapy or chemotherapy of local or distant recurrences of thyroid malignancy that are not amenable to surgical or radioiodine treatment.

CT imaging of complications of catheter ablation for atrial fibrillation

International Nuclear Information System (INIS)

Shroff, G.S.; Guirguis, M.S.; Ferguson, E.C.; Oldham, S.A.A.; Kantharia, B.K.

2014-01-01

The complication rate following radiofrequency catheter ablation for atrial fibrillation is low (<5%). Complications include pericardial effusion, cardiac tamponade, pulmonary vein stenosis, oesophageal ulceration or perforation, atrio-oesophageal fistula formation, stroke/transient ischaemic attack, phrenic nerve injury, haematoma at the puncture site, and femoral arteriovenous fistula. Among available imaging tools, computed tomography (CT) can be very useful in diagnosing complications of the procedure, particularly in the subacute and delayed stages after ablation. This review illustrates CT imaging of several of the common and uncommon complications of radiofrequency catheter ablation

Automated planning of ablation targets in atrial fibrillation treatment

Science.gov (United States)

Keustermans, Johannes; De Buck, Stijn; Heidbüchel, Hein; Suetens, Paul

2011-03-01

Catheter based radio-frequency ablation is used as an invasive treatment of atrial fibrillation. This procedure is often guided by the use of 3D anatomical models obtained from CT, MRI or rotational angiography. During the intervention the operator accurately guides the catheter to prespecified target ablation lines. The planning stage, however, can be time consuming and operator dependent which is suboptimal both from a cost and health perspective. Therefore, we present a novel statistical model-based algorithm for locating ablation targets from 3D rotational angiography images. Based on a training data set of 20 patients, consisting of 3D rotational angiography images with 30 manually indicated ablation points, a statistical local appearance and shape model is built. The local appearance model is based on local image descriptors to capture the intensity patterns around each ablation point. The local shape model is constructed by embedding the ablation points in an undirected graph and imposing that each ablation point only interacts with its neighbors. Identifying the ablation points on a new 3D rotational angiography image is performed by proposing a set of possible candidate locations for each ablation point, as such, converting the problem into a labeling problem. The algorithm is validated using a leave-one-out-approach on the training data set, by computing the distance between the ablation lines obtained by the algorithm and the manually identified ablation points. The distance error is equal to 3.8+/-2.9 mm. As ablation lesion size is around 5-7 mm, automated planning of ablation targets by the presented approach is sufficiently accurate.

Surgical Ablation of Atrial Fibrillation Using Energy Sources.

Science.gov (United States)

Brick, Alexandre Visconti; Braile, Domingo Marcolino

2015-01-01

Surgical ablation, concomitant with other operations, is an option for treatment in patients with chronic atrial fibrillation. The aim of this study is to present a literature review on surgical ablation of atrial fibrillation in patients undergoing cardiac surgery, considering energy sources and return to sinus rhythm. A comprehensive survey was performed in the literature on surgical ablation of atrial fibrillation considering energy sources, sample size, study type, outcome (early and late), and return to sinus rhythm. Analyzing studies with immediate results (n=5), the percentage of return to sinus rhythm ranged from 73% to 96%, while those with long-term results (n=20) (from 12 months on) ranged from 62% to 97.7%. In both of them, there was subsequent clinical improvement of patients who underwent ablation, regardless of the energy source used. Surgical ablation of atrial fibrillation is essential for the treatment of this arrhythmia. With current technology, it may be minimally invasive, making it mandatory to perform a procedure in an attempt to revert to sinus rhythm in patients requiring heart surgery.

Air-kerma evaluation at the maze entrance of HDR brachytherapy facilities

International Nuclear Information System (INIS)

Pujades, M C; Granero, D; Vijande, J; Ballester, F; Perez-Calatayud, J; Papagiannis, P; Siebert, F A

2014-01-01

In the absence of procedures for evaluating the design of brachytherapy (BT) facilities for radiation protection purposes, the methodology used for external beam radiotherapy facilities is often adapted. The purpose of this study is to adapt the NCRP 151 methodology for estimating the air-kerma rate at the door in BT facilities. Such methodology was checked against Monte Carlo (MC) techniques using the code Geant4. Five different facility designs were studied for 192 Ir and 60 Co HDR applications to account for several different bunker layouts. For the estimation of the lead thickness needed at the door, the use of transmission data for the real spectra at the door instead of the ones emitted by 192 Ir and 60 Co will reduce the lead thickness by a factor of five for 192 Ir and ten for 60 Co. This will significantly lighten the door and hence simplify construction and operating requirements for all bunkers. The adaptation proposed in this study to estimate the air-kerma rate at the door depends on the complexity of the maze: it provides good results for bunkers with a maze (i.e. similar to those used for linacs for which the NCRP 151 methodology was developed) but fails for less conventional designs. For those facilities, a specific Monte Carlo study is in order for reasons of safety and cost-effectiveness. (paper)

Air-kerma evaluation at the maze entrance of HDR brachytherapy facilities.

Science.gov (United States)

Pujades, M C; Granero, D; Vijande, J; Ballester, F; Perez-Calatayud, J; Papagiannis, P; Siebert, F A

2014-12-01

In the absence of procedures for evaluating the design of brachytherapy (BT) facilities for radiation protection purposes, the methodology used for external beam radiotherapy facilities is often adapted. The purpose of this study is to adapt the NCRP 151 methodology for estimating the air-kerma rate at the door in BT facilities. Such methodology was checked against Monte Carlo (MC) techniques using the code Geant4. Five different facility designs were studied for (192)Ir and (60)Co HDR applications to account for several different bunker layouts.For the estimation of the lead thickness needed at the door, the use of transmission data for the real spectra at the door instead of the ones emitted by (192)Ir and (60)Co will reduce the lead thickness by a factor of five for (192)Ir and ten for (60)Co. This will significantly lighten the door and hence simplify construction and operating requirements for all bunkers.The adaptation proposed in this study to estimate the air-kerma rate at the door depends on the complexity of the maze: it provides good results for bunkers with a maze (i.e. similar to those used for linacs for which the NCRP 151 methodology was developed) but fails for less conventional designs. For those facilities, a specific Monte Carlo study is in order for reasons of safety and cost-effectiveness.

Dynamics of tissue shrinkage during ablative temperature exposures

International Nuclear Information System (INIS)

Rossmann, Christian; Haemmerich, Dieter; Garrett-Mayer, Elizabeth; Rattay, Frank

2014-01-01

There is a lack of studies that examine the dynamics of heat-induced shrinkage of organ tissues. Clinical procedures such as radiofrequency ablation, microwave ablation or high-intensity focused ultrasound, use heat to treat diseases such as cancer and cardiac arrhythmia. When heat is applied to tissues, shrinkage occurs due to protein denaturation, dehydration and contraction of collagen at temperatures greater 50 °C. This is particularly relevant for image-guided procedures such as tumor ablation, where pre- and post-treatment images are compared and any changes in dimensions must be considered to avoid misinterpretations of the treatment outcome. We present data from ex vivo, isothermal shrinkage tests in porcine liver tissue, where axial changes in tissue length were recorded during 15 min of heating to temperatures between 60 and 95 °C. A mathematical model was developed to accurately describe the time and temperature-dependent shrinkage behavior. The shrinkage dynamics had the same characteristics independent of temperature; the estimated relative shrinkage, adjusted for time since death, after 15 min heating to temperatures of 60, 65, 75, 85 and 95 °C, was 12.3, 13.8, 16.6, 19.2 and 21.7%, respectively. Our results demonstrate the shrinkage dynamics of organ tissues, and suggest the importance of considering tissue shrinkage for thermal ablative treatments. (paper)

A review of the safety aspects of radio frequency ablation

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Abhishek Bhaskaran

2015-09-01

Full Text Available In light of recent reports showing high incidence of silent cerebral infarcts and organized atrial arrhythmias following radiofrequency (RF atrial fibrillation (AF ablation, a review of its safety aspects is timely. Serious complications do occur during supraventricular tachycardia (SVT ablations and knowledge of their incidence is important when deciding whether to proceed with ablation. Evidence is emerging for the probable role of prophylactic ischemic scar ablation to prevent VT. This might increase the number of procedures performed. Here we look at the various complications of RF ablation and also the methods to minimize them. Electronic database was searched for relevant articles from 1990 to 2015. With better awareness and technological advancements in RF ablation the incidence of complications has improved considerably. In AF ablation it has decreased from 6% to less than 4% comprising of vascular complications, cardiac tamponade, stroke, phrenic nerve injury, pulmonary vein stenosis, atrio-esophageal fistula (AEF and death. Safety of SVT ablation has also improved with less than 1% incidence of AV node injury in AVNRT ablation. In VT ablation the incidence of major complications was 5–11%, up to 3.4%, up to 1.8% and 4.1–8.8% in patients with structural heart disease, without structural heart disease, prophylactic ablations and epicardial ablations respectively. Vascular and pericardial complications dominated endocardial and epicardial VT ablations respectively. Up to 3% mortality and similar rates of tamponade were reported in endocardial VT ablation. Recent reports about the high incidence of asymptomatic cerebral embolism during AF ablation are concerning, warranting more research into its etiology and prevention.

Topography-guided custom ablation treatment for treatment of keratoconus

Directory of Open Access Journals (Sweden)

Rohit Shetty

2013-01-01

Full Text Available Keratoconus is a progressive ectatic disorder of the cornea which often presents with fluctuating refraction and high irregular astigmatism. Correcting the vision of these patients is often a challenge because glasses are unable to correct the irregular astigmatism and regular contact lenses may not fit them very well. Topography-guided custom ablation treatment (T-CAT is a procedure of limited ablation of the cornea using excimer laser with the aim of regularizing the cornea, improving the quality of vision and possibly contact lens fit. The aim of the procedure is not to give a complete refractive correction. It has been tried with a lot of success by various groups of refractive surgeons around the world but a meticulous and methodical planning of the procedure is essential to ensure optimum results. In this paper, we attempt to elucidate the planning for a T-CAT procedure for various types of cones and asphericities.

Clinical impact of rotor ablation in atrial fibrillation: a systematic review.

Science.gov (United States)

Parameswaran, Ramanathan; Voskoboinik, Aleksandr; Gorelik, Alexandra; Lee, Geoffrey; Kistler, Peter M; Sanders, Prashanthan; Kalman, Jonathan M

2018-01-11

Rotor mapping and ablation have gained favour over the recent years as an emerging ablation strategy targeting drivers of atrial fibrillation (AF). Their efficacy, however, has been a topic of great debate with variable outcomes across centres. The aim of this study was to systematically review the recent medical literature to determine the medium-term outcomes of rotor ablation in patients with paroxysmal atrial fibrillation (PAF) and persistent atrial fibrillation (PeAF). A systematic search of the contemporary scientific literature (PubMed and EMBASE) was performed in August 2017. Only studies assessing arrhythmia-free survival from rotor ablation of AF were included. We used the random-effects model to assess the primary outcome of pooled medium-term single-procedure AF-free survival for both PAF and PeAF. Success rates from multiple procedures and complication rates were also examined. We included 11 observational studies (4 PAF and 10 PeAF) with a total of 556 patients (166 PAF and 390 PeAF). Pooled single-procedure freedom from AF was 37.8% [95% confidence interval 5.6-86.3%] at a mean follow-up period of 13.8 ± 1.8 months for PAF and 59.2% (95% CI 41.4-74.9%) at a mean follow-up period of 12.9 ± 6 months for PeAF. There was a marked heterogeneity between studies (I2 = 93.8% for PAF and 88.3% for PeAF). The mean complication rate of rotor ablation among the reported studies was 3.4%. The wide variability in success rate between different centres performing rotor ablations suggests that the optimal ablation strategy, particularly targeting rotors, is unclear. Results from randomized studies are necessary before this technique can be considered as an established clinical tool. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2018. For permissions, please email: journals.permissions@oup.com.

Gastrodia elata Bl. Attenuated learning deficits induced by forced-swimming stress in the inhibitory avoidance task and Morris water maze.

Science.gov (United States)

Chen, Pei-Ju; Liang, Keng-Chen; Lin, Hui-Chen; Hsieh, Ching-Liang; Su, Kuan-Pin; Hung, Mei-Chu; Sheen, Lee-Yan

2011-06-01

This study adopted the forced-swimming paradigm to induce depressive symptoms in rats and evaluated the effects on learning and memory processing. Furthermore, the effects of the water extract of Gastrodia elata Bl., a well-known Chinese traditional medicine, on amnesia in rats subjected to the forced-swimming procedure were studied. Rats were subjected to the forced-swimming procedure, and the inhibitory avoidance task and Morris water maze were used to assess learning and memory performance. The acquisition of the two tasks was mostly impaired after the 15-minute forced-swimming procedure. Administration of the water extract of G. elata Bl. for 21 consecutive days at a dosage of 0.5 or 1.0 g/kg of body weight significantly improved retention in the inhibitory avoidance test, and the lower dose showed a better effect than the higher one and the antidepressant fluoxetine (18 mg/kg of body weight). In the Morris water maze, the lower dose of the water extract of G. elata Bl. significantly improved retention by shortening escape latency in the first test session and increasing the time in searching the target zone during the probe test. These findings suggest that water extracts of G. elata Bl. ameliorate the learning and memory deficits induced by forced swimming.

Surgical outcome of Fontan conversion and arrhythmia surgery: Need a pacemaker?

Science.gov (United States)

Terada, Takafumi; Sakurai, Hajime; Nonaka, Toshimichi; Sakurai, Takahisa; Sugiura, Junya; Taneichi, Tetsuyoshi; Ohtsuka, Ryohei

2014-07-01

Atrial tachyarrhythmias are frequent complications in the late period after the Fontan procedure, and important risk factors for a poor prognosis. The impact of Fontan conversion and arrhythmia surgery in failed Fontan patients has been described in many reports. We evaluated our experience with Fontan conversion procedures, concomitant arrhythmia surgery, and pacemaker implantation. We reviewed the hospital records of 25 consecutive patients who underwent a Fontan conversion procedure from January 2004 to March 2012. Twenty-four patients had arrhythmia surgery using cryoablation and radiofrequency ablation at the time of conversion. A bilateral atrial maze procedure was performed in 6 patients, right-side maze in 15, and isthmus block in 3. Three patients with a diagnosis of corrected transposition of the great arteries underwent simultaneous pacemaker implantation electively. There was no early death and one late death during a mean follow-up period of 21.2 months. Three tachyarrhythmia recurrences developed, and there were 4 occurrences of sinus bradycardia. Five of these patients required postoperative pacemaker implantation. The mid-term results of Fontan conversion and arrhythmia surgery in our institute were satisfactory. The occurrence of unexpected postoperative pacemaker requirement was high in the patients who underwent a right atrial or bilateral atrial maze procedure. Pacemaker or lead implantation is recommended for patients planned to undergo a right-side or full maze procedure. © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Contemporary management of patients undergoing atrial fibrillation ablation: in-hospital and 1-year follow-up findings from the ESC-EHRA atrial fibrillation ablation long-term registry.

Science.gov (United States)

Arbelo, Elena; Brugada, Josep; Blomström-Lundqvist, Carina; Laroche, Cécile; Kautzner, Josef; Pokushalov, Evgeny; Raatikainen, Pekka; Efremidis, Michael; Hindricks, Gerhard; Barrera, Alberto; Maggioni, Aldo; Tavazzi, Luigi; Dagres, Nikolaos

2017-05-01

The ESC-EHRA Atrial Fibrillation Ablation Long-Term registry is a prospective, multinational study that aims at providing an accurate picture of contemporary real-world ablation for atrial fibrillation (AFib) and its outcome. A total of 104 centres in 27 European countries participated and were asked to enrol 20-50 consecutive patients scheduled for first and re-do AFib ablation. Pre-procedural, procedural and 1-year follow-up data were captured on a web-based electronic case record form. Overall, 3630 patients were included, of which 3593 underwent an AFib ablation (98.9%). Median age was 59 years and 32.4% patients had lone atrial fibrillation. Pulmonary vein isolation was attempted in 98.8% of patients and achieved in 95-97%. AFib-related symptoms were present in 97%. In-hospital complications occurred in 7.8% and one patient died due to an atrioesophageal fistula. One-year follow-up was performed in 3180 (88.6%) at a median of 12.4 months (11.9-13.4) after ablation: 52.8% by clinical visit, 44.2% by telephone contact and 3.0% by contact with the general practitioner. At 12-months, the success rate with or without antiarrhythmic drugs (AADs) was 73.6%. A significant portion (46%) was still on AADs. Late complications included 14 additional deaths (4 cardiac, 4 vascular, 6 other causes) and 333 (10.7%) other complications. AFib ablation in clinical practice is mostly performed in symptomatic, relatively young and otherwise healthy patients. Overall success rate is satisfactory, but complication rate remains considerable and a significant portion of patients remain on AADs. Monitoring after ablation shows wide variations. Antithrombotic treatment after ablation shows insufficient guideline-adherence. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For Permissions, please email: journals.permissions@oup.com.

Percutaneous laser ablation of unresectable primary and metastatic adrenocortical carcinoma

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Pacella, Claudio M. [Regina Apostolorum Hospital, Department of Diagnostic Imaging and Interventional Radiology, Via San Francesco 50, Albano Laziale, Rome 00041 (Italy)], E-mail: claudiomaurizio.pacella@fastwebnet.it; Stasi, Roberto; Bizzarri, Giancarlo; Pacella, Sara; Graziano, Filomena Maria; Guglielmi, Rinaldo; Papini, Enrico [Regina Apostolorum Hospital, Department of Diagnostic Imaging and Interventional Radiology, Via San Francesco 50, Albano Laziale, Rome 00041 (Italy)

2008-04-15

Purpose: To evaluate the feasibility, safety, and clinical benefits of percutaneous laser ablation (PLA) in patients with unresectable primary and metastatic adrenocortical carcinoma (ACC). Patients and methods: Four patients with hepatic metastases from ACC and a Cushing's syndrome underwent ultrasound-guided PLA. In one case the procedure was performed also on the primary tumor. Results: After three sessions of PLA, the primary tumor of 15 cm was ablated by 75%. After 1-4 (median 1) sessions of PLA, five liver metastases ranging from 2 to 5 cm were completely ablated, while the sixth tumor of 12 cm was ablated by 75%. There were no major complications. Treatment resulted in an improvement of performance status and a reduction of the daily dosage of mitotane in all patients. The three patients with liver metastases presented a marked decrease of 24-h urine cortisol levels, an improved control of hypertension and a mean weight loss of 2.8 kg. After a median follow-up after PLA of 27.0 months (range, 9-48 months), two patients have died of tumor progression, while two other patients remain alive and free of disease. Conclusions: Percutaneous laser ablation is a feasible, safe and well tolerated procedure for the palliative treatment of unresectable primary and metastatic ACC. Further study is required to evaluate the impact of PLA on survival.

Percutaneous laser ablation of unresectable primary and metastatic adrenocortical carcinoma

International Nuclear Information System (INIS)

Pacella, Claudio M.; Stasi, Roberto; Bizzarri, Giancarlo; Pacella, Sara; Graziano, Filomena Maria; Guglielmi, Rinaldo; Papini, Enrico

2008-01-01

Purpose: To evaluate the feasibility, safety, and clinical benefits of percutaneous laser ablation (PLA) in patients with unresectable primary and metastatic adrenocortical carcinoma (ACC). Patients and methods: Four patients with hepatic metastases from ACC and a Cushing's syndrome underwent ultrasound-guided PLA. In one case the procedure was performed also on the primary tumor. Results: After three sessions of PLA, the primary tumor of 15 cm was ablated by 75%. After 1-4 (median 1) sessions of PLA, five liver metastases ranging from 2 to 5 cm were completely ablated, while the sixth tumor of 12 cm was ablated by 75%. There were no major complications. Treatment resulted in an improvement of performance status and a reduction of the daily dosage of mitotane in all patients. The three patients with liver metastases presented a marked decrease of 24-h urine cortisol levels, an improved control of hypertension and a mean weight loss of 2.8 kg. After a median follow-up after PLA of 27.0 months (range, 9-48 months), two patients have died of tumor progression, while two other patients remain alive and free of disease. Conclusions: Percutaneous laser ablation is a feasible, safe and well tolerated procedure for the palliative treatment of unresectable primary and metastatic ACC. Further study is required to evaluate the impact of PLA on survival

Single-shot and single-spot measurement of laser ablation threshold for carbon nanotubes

International Nuclear Information System (INIS)

Lednev, Vasily N; Pershin, Sergey M; Bunkin, Alexey F; Obraztsova, Elena D; Kudryashov, Sergey I

2013-01-01

A simple and convenient procedure for single-shot, single-spot ablation threshold measurement is developed. It is based on the employment of cylindrical lens to obtain an elliptical Gaussian laser spot. The ablated spot chords that are parallel to the minor axis are measured across the spot major axis, which is proportional to the fluence cross-section, thus providing wide range dependence of damaged spot size versus fluence in one spot measurement. For both conventional and newly developed procedures the ablation threshold for typical Nd:YAG laser parameters (1064 nm, 10 ns) is measured as 50 ± 5 mJ cm -2 , which is one order of magnitude lower than that for bulk graphite.

Attitudes toward catheter ablation for atrial fibrillation : A nationwide survey among Danish cardiologists

NARCIS (Netherlands)

Vadmann, Henrik; Pedersen, S.S.; Nielsen, Jens Cosedis; Rodrigo-Domingo, Maria; Pehrson, Steen; Johannessen, Arne; Hansen, Peter Steen; Johansen, Jens Brock; Riahi, Sam

2015-01-01

BackgroundCatheter ablation for atrial fibrillation (AF) is an important but expensive procedure that is the subject of some debate. Physicians' attitudes toward catheter ablation may influence promotion and patient acceptance. This is the first study to examine the attitudes of Danish cardiologists

Cholecystokinin-Assisted Hydrodissection of the Gallbladder Fossa during FDG PET/CT-guided Liver Ablation

Energy Technology Data Exchange (ETDEWEB)

Tewari, Sanjit O., E-mail: tewaris@mskcc.org [Memorial Sloan-Kettering Cancer Center, Molecular Imaging and Therapy Service, Department of Radiology (United States); Petre, Elena N., E-mail: petree@mskcc.org [Memorial Sloan-Kettering Cancer Center, Interventional Radiology Service, Department of Radiology (United States); Osborne, Joseph, E-mail: osbornej@mskcc.org [Memorial Sloan-Kettering Cancer Center, Molecular Imaging and Therapy Service, Department of Radiology (United States); Sofocleous, Constantinos T., E-mail: sofoclec@mskcc.org [Memorial Sloan-Kettering Cancer Center, Interventional Radiology Service, Department of Radiology (United States)

2013-12-15

A 68-year-old female with colorectal cancer developed a metachronous isolated fluorodeoxyglucose-avid (FDG-avid) segment 5/6 gallbladder fossa hepatic lesion and was referred for percutaneous ablation. Pre-procedure computed tomography (CT) images demonstrated a distended gallbladder abutting the segment 5/6 hepatic metastasis. In order to perform ablation with clear margins and avoid direct puncture and aspiration of the gallbladder, cholecystokinin was administered intravenously to stimulate gallbladder contraction before hydrodissection. Subsequently, the lesion was ablated successfully with sufficient margins, of greater than 1.0 cm, using microwave with ultrasound and FDG PET/CT guidance. The patient tolerated the procedure very well and was discharged home the next day.

Use of the Open Field Maze to measure locomotor and anxiety-like behavior in mice.

Science.gov (United States)

Seibenhener, Michael L; Wooten, Michael C

2015-02-06

Animal models have proven to be invaluable to researchers trying to answer questions regarding the mechanisms of behavior. The Open Field Maze is one of the most commonly used platforms to measure behaviors in animal models. It is a fast and relatively easy test that provides a variety of behavioral information ranging from general ambulatory ability to data regarding the emotionality of the subject animal. As it relates to rodent models, the procedure allows the study of different strains of mice or rats both laboratory bred and wild-captured. The technique also readily lends itself to the investigation of different pharmacological compounds for anxiolytic or anxiogenic effects. Here, a protocol for use of the open field maze to describe mouse behaviors is detailed and a simple analysis of general locomotor ability and anxiety-related emotional behaviors between two strains of C57BL/6 mice is performed. Briefly, using the described protocol we show Wild Type mice exhibited significantly less anxiety related behaviors than did age-matched Knock Out mice while both strains exhibited similar ambulatory ability.

Ten-year literature review of global endometrial ablation with the NovaSure® device

Directory of Open Access Journals (Sweden)

Gimpelson RJ

2014-03-01

Full Text Available Richard J Gimpelson Mercy Clinic, Minimally Invasive Gynecology, Department of Obstetrics and Gynecology, Mercy Hospital St Louis, St Louis, MO, USA Abstract: This review examines the peer-reviewed literature describing prospective studies that report amenorrhea rates, patient satisfaction, and surgical reintervention rates following the NovaSure® endometrial ablation procedure. A search of the English-language literature published from 2000 to 2011 was conducted using PubMed. Ten prospective studies, six single-arm NovaSure trials, and four randomized controlled trials comparing the NovaSure procedure with other global endometrial ablation modalities met the inclusion criteria and were reviewed. The follow-up periods ranged from 6 to 60 months. Amenorrhea rates for the NovaSure procedure ranged from 30.0% to 75.0%. Patients who reported being satisfied with the NovaSure procedure ranged from 85.0% to 94.0%. In randomized controlled trials with other global endometrial ablation modalities, amenorrhea rates at 12 months with the NovaSure procedure ranged from 43.0% to 56.0%, while other modalities ranged from 8% to 24%. In addition, this manuscript reviews the following: the NovaSure technology; use of the NovaSure procedure in the office setting; intraoperative and postoperative pain; effects on premenstrual syndrome (PMS; dysmenorrhea; special circumstances, including presence of uterine disease, history of cesarean delivery, coagulopathy, or use of anticoagulant medication; post-procedure uterine cavity assessment and cancer risk; contraception and pregnancy; and safety. Keywords: abnormal uterine bleeding, menorrhagia, endometrial ablation, NovaSure®

Navigation using sensory substitution in real and virtual mazes.

Science.gov (United States)

Chebat, Daniel-Robert; Maidenbaum, Shachar; Amedi, Amir

2015-01-01

Under certain specific conditions people who are blind have a perception of space that is equivalent to that of sighted individuals. However, in most cases their spatial perception is impaired. Is this simply due to their current lack of access to visual information or does the lack of visual information throughout development prevent the proper integration of the neural systems underlying spatial cognition? Sensory Substitution devices (SSDs) can transfer visual information via other senses and provide a unique tool to examine this question. We hypothesize that the use of our SSD (The EyeCane: a device that translates distance information into sounds and vibrations) can enable blind people to attain a similar performance level as the sighted in a spatial navigation task. We gave fifty-six participants training with the EyeCane. They navigated in real life-size mazes using the EyeCane SSD and in virtual renditions of the same mazes using a virtual-EyeCane. The participants were divided into four groups according to visual experience: congenitally blind, low vision & late blind, blindfolded sighted and sighted visual controls. We found that with the EyeCane participants made fewer errors in the maze, had fewer collisions, and completed the maze in less time on the last session compared to the first. By the third session, participants improved to the point where individual trials were no longer significantly different from the initial performance of the sighted visual group in terms of errors, time and collision.

Role of contact force-guided radiofrequency catheter ablation for treatment of atrial fibrillation: A systematic review and meta-analysis.

Science.gov (United States)

Lin, Hui; Chen, Yi-He; Hou, Jian-Wen; Lu, Zhao-Yang; Xiang, Yin; Li, Yi-Gang

2017-09-01

CF-sensing catheter emerged as a novel ablation technology and was increasingly used in clinical practice. Nonetheless, available evidence of efficacy and safety comparison between CF-guided RF catheter ablation and non-CF-guided ablation for treatment of AF was still lacking. Twenty-two eligible studies were included after systematic review through the MEDLINE, Google Scholar, the Cochrane Library and PubMed databases. AF/atrial tachycardia-free survival was markedly improved in CF-guided catheter ablation compared with non-CF-guided ablation at a median 12-month follow-up (RR: 1.12, 95% CI: 1.06-1.19, P = 0.000, fixed). Notably, CF-guided catheter ablation presented a robust survival benefit for treatment of paroxysmal AF (RR: 1.10, 95% CI: 1.03-1.18, P = 0.005, fixed), but not persistent AF (RR: 1.07, 95% CI: 0.89-1.28, P = 0.466, fixed). Moreover, procedure time (WMD: -23.87, 95% CI: -33.83 to -13.91, P = 0.000, random), fluoroscopy time (WMD: -7.78, 95% CI: -13.93 to -1.63, P = 0.013, random) and RF time (WMD: -3.98, 95% CI: -7.78 to -0.17, P = 0.040, random) were significantly reduced in CF-guided catheter ablation. The incidence of procedure-related complications did not differ between these two technologies (RR: 0.83, 95% CI: 0.59 to 1.16, P = 0.271, fixed). CF-guided RF catheter ablation was associated with a significant AF/atrial tachycardia-free survival benefit compared with non-CF-guided ablation in patients with paroxysmal AF rather than persistent AF. In addition, CF-guided ablation strategy also reduced the procedure time, fluoroscopy time, as well as RF time despite no distinct effect on the alleviation of procedure-related complications. © 2017 Wiley Periodicals, Inc.

Tests of the Aversive Summation Hypothesis in Rats: Effects of Restraint Stress on Consummatory Successive Negative Contrast and Extinction in the Barnes Maze

Science.gov (United States)

Ortega, Leonardo A.; Prado-Rivera, Mayerli A.; Cardenas-Poveda, D. Carolina; McLinden, Kristina A.; Glueck, Amanda C.; Gutierrez, German; Lamprea, Marisol R.; Papini, Mauricio R.

2013-01-01

The present research explored the effects of restraint stress on two situations involving incentive downshift: consummatory successive negative contrast (cSNC) and extinction of escape behavior in the Barnes maze. First, Experiment 1 confirmed that the restraint stress procedure used in these experiments increased levels of circulating…

Ablation, Thermal Response, and Chemistry Program for Analysis of Thermal Protection Systems

Science.gov (United States)

Milos, Frank S.; Chen, Yih-Kanq

2010-01-01

In previous work, the authors documented the Multicomponent Ablation Thermochemistry (MAT) and Fully Implicit Ablation and Thermal response (FIAT) programs. In this work, key features from MAT and FIAT were combined to create the new Fully Implicit Ablation, Thermal response, and Chemistry (FIATC) program. FIATC is fully compatible with FIAT (version 2.5) but has expanded capabilities to compute the multispecies surface chemistry and ablation rate as part of the surface energy balance. This new methodology eliminates B' tables, provides blown species fractions as a function of time, and enables calculations that would otherwise be impractical (e.g. 4+ dimensional tables) such as pyrolysis and ablation with kinetic rates or unequal diffusion coefficients. Equations and solution procedures are presented, then representative calculations of equilibrium and finite-rate ablation in flight and ground-test environments are discussed.

Discussion on the optimization design on mazes of medical linear accelerator facilities

International Nuclear Information System (INIS)

Cao Lei; Zhang Wenyi; Liu Baiqun; Hou Changsong; Zhao Lancai

2007-01-01

Objective: To discuss the differences on the design and evaluation between the L-type and Z-type mazes of typical medical electric linear accelerator. Methods: The study is conducted by choosing some typical medical electric linear accelerators used in China, further analyzing on the running conditions of the accelerators in the mode of MV-X-ray, and referring to the late NCRP Report 51 and other references. Results: The radiation levels at the access to therapy room are effectively reduced by Z-type mazes. Conclusions: The Z-type mazes are advisable during the optimization design. (authors)

Three-year follow-up and quality of life of endovenous radiofrequency ablation of the great saphenous vein with the ClosureFast™ procedure: Influence of BMI and CEAP class.

Science.gov (United States)

Casana, Renato; Tolva, Valerio Stefano; Odero, Andrea; Malloggi, Chiara; Parati, Gianfranco

2018-01-01

Purpose Endovascular ablation of the great saphenous vein has been proposed as a less invasive alternative to conventional ligation and stripping of varicose veins. Outcomes of patients treated with the radiofrequency ablation ClosureFast™ system over an eight-year period from a single-center were evaluated. Methods Three-year follow-up data included duplex ultrasound scan, complication rate, and questionnaires to assess patients' QOL, level of pain, and days off work. Results A total of 1080 consecutive patients (49.5 ± 18.6 years, 72% female, mean body mass index: 25.44 ± 4.1 kg m -2 ) underwent radiofrequency ablation for incompetent saphenous veins in a single institution. Occlusion of the great saphenous vein was obtained in 98.6% and 93.8% cases at the end of the procedures and within 36 months, respectively. Only three deep venous thromboses and minor complications occurred in this series throughout the first week from the procedure. A decrease of the external vein diameter, equal to 72.7% and 31.1% of the pretreatment diameter, was observed at 1 week and 36 months, respectively. The average Aberdeen Varicose Vein Questionnaire score improved from 18.06 ± 9.47 before treatment to 11.56 ± 10.23 at 12 months, with no significant differences in the subsequent follow-up. SF-36 QOL scores significantly improved after the procedure in all domains, while there were no changes over time. Patients reported a prompt return to normal daily activities (1.5 ± 0.7 days) and work (3.1 ± 1.9 days). Body mass index influenced QOL scores, while it did not affect great saphenous vein diameter reduction during the follow-up. On the contrary, Clinical Etiologic Anatomic Pathophysiologic class significantly influenced both great saphenous vein diameter reduction after the treatment and QOL scores within 36 months. Conclusion Results of this retrospective monocentric, large patients study suggest that radiofrequency ablation of the great

A tubular electrode for radiofrequency ablation therapy

KAUST Repository

Antunes, Carlos Lemos Lemos Lemos

2012-07-06

Purpose – Due to its good mechanical and biocompatibility characteristics, nitinol SEMS is a popular endoprothesis used for relieving stricture problems in hollow organs due to carcinomas. Besides its mechanical application, SEMS can be regarded as well as potential electrode for performing RF ablation therapy on the tumor. The purpose of this work is to perform numerical and experimental analyses in order to characterize the lesion volume induced in biological tissue using this kind of tubular electrode. Design/methodology/approach – Data concerning electrical conductivity and dimension of the damaged tissue after RF ablation procedure were obtained from ex vivo samples. Next, numerical models using 3D finite element method were obtained reassembling the conditions considered at experimentation setup and results were compared. Findings – Numerical and experimental results show that a regular volume of damaged tissue can be obtained considering this type of electrode. Also, results obtained from numerical simulation are close to those obtained by experimentation. Originality/value – SEMSs, commonly used as devices to minimize obstruction problems due to the growth of tumors, may still be considered as an active electrode for RF ablation procedures. A method considering this observation is presented in this paper. Also, numerical simulation can be regarded in this case as a tool for determining the lesion volume.

Hepatocellular carcinoma after radiofrequency ablation: recurrent pattern and influenting factor

Energy Technology Data Exchange (ETDEWEB)

Kang, Myong Jin; Nam, Kyung Jin; Oh, Jong Young; Choi, Jong Chul; Park, Byeong Ho; Lee, Yung Il [College of Medicine, DongA Univ., Pusan (Korea, Republic of)

2002-02-01

To evaluate patterns of recurrence and factors which influence them in radiofreqency (RF) ablation for the treatment of hepatocellular carcinoma (HCC). Between May 1999 and March 2000, 69 patients with 82 HCCs underwent RF ablation for complete necrosis. They were diagnosed by tissue biopsy or tumor marker, and the results of triphasic spiral CT. The indications were that nodular lesions were clearly visualized at sonography, less than 5 cm in size and less than four in number, and that patients had no history of previous treatment. Local therapeutic efficacy such as complete necrosis and marginal recurrence, and new lesions were evaluated by means of triphasic spiral CT performed at least six months after the completion of ablation. We then analyzed the correlation between local therapeutic efficacy and various influential factors such as tumor size, whether the tumor was attached to the portal vein, gross morphology, Child-Pugh classification, and {alpha}-fetoprotein level vefore the procedure, as well as the correlation between new lesions and influential factors which included the {alpha}-fetoprotein level before the procedure, Child-Pugh classification, and multiplicity per person. During a mean follow-up period of 8.95 (range, 6-14) months after RF ablation, the rate of complete necrosis and of marginal recurrence was 91% and 12%, respectively. When a tumor was larger and was attached to a large branch of the portal vien, the incidence of incomplete necrosis and marginal recurrence was greater. The occurrence rate of new lesion was 19.4%. When the {alpha}-fetoprotein level before the procedure was higher and a tumor was multiple in number, new lesions occurred more frequently. Sufficient knowledge of patterns of recurrence and the factors which influence them might improve the therapeutic effects of RF ablation in patients with HCC.

Disentangling the cognitive components supporting Austin Maze performance in left versus right temporal lobe epilepsy.

Science.gov (United States)

Hocking, Julia; Thomas, Hannah J; Dzafic, Ilvana; Williams, Rebecca J; Reutens, David C; Spooner, Donna M

2013-12-01

Neuropsychological tests requiring patients to find a path through a maze can be used to assess visuospatial memory performance in temporal lobe pathology, particularly in the hippocampus. Alternatively, they have been used as a task sensitive to executive function in patients with frontal lobe damage. We measured performance on the Austin Maze in patients with unilateral left and right temporal lobe epilepsy (TLE), with and without hippocampal sclerosis, compared to healthy controls. Performance was correlated with a number of other neuropsychological tests to identify the cognitive components that may be associated with poor Austin Maze performance. Patients with right TLE were significantly impaired on the Austin Maze task relative to patients with left TLE and controls, and error scores correlated with their performance on the Block Design task. The performance of patients with left TLE was also impaired relative to controls; however, errors correlated with performance on tests of executive function and delayed recall. The presence of hippocampal sclerosis did not have an impact on maze performance. A discriminant function analysis indicated that the Austin Maze alone correctly classified 73.5% of patients as having right TLE. In summary, impaired performance on the Austin Maze task is more suggestive of right than left TLE; however, impaired performance on this visuospatial task does not necessarily involve the hippocampus. The relationship of the Austin Maze task with other neuropsychological tests suggests that differential cognitive components may underlie performance decrements in right versus left TLE. © 2013.

Characterization of the rat exploratory behavior in the elevated plus-maze with Markov chains.

Science.gov (United States)

Tejada, Julián; Bosco, Geraldine G; Morato, Silvio; Roque, Antonio C

2010-11-30

The elevated plus-maze is an animal model of anxiety used to study the effect of different drugs on the behavior of the animal. It consists of a plus-shaped maze with two open and two closed arms elevated 50cm from the floor. The standard measures used to characterize exploratory behavior in the elevated plus-maze are the time spent and the number of entries in the open arms. In this work, we use Markov chains to characterize the exploratory behavior of the rat in the elevated plus-maze under three different conditions: normal and under the effects of anxiogenic and anxiolytic drugs. The spatial structure of the elevated plus-maze is divided into squares, which are associated with states of a Markov chain. By counting the frequencies of transitions between states during 5-min sessions in the elevated plus-maze, we constructed stochastic matrices for the three conditions studied. The stochastic matrices show specific patterns, which correspond to the observed behaviors of the rat under the three different conditions. For the control group, the stochastic matrix shows a clear preference for places in the closed arms. This preference is enhanced for the anxiogenic group. For the anxiolytic group, the stochastic matrix shows a pattern similar to a random walk. Our results suggest that Markov chains can be used together with the standard measures to characterize the rat behavior in the elevated plus-maze. Copyright © 2010 Elsevier B.V. All rights reserved.

Real-time tumor ablation simulation based on the dynamic mode decomposition method

KAUST Repository

Bourantas, George C.

2014-05-01

Purpose: The dynamic mode decomposition (DMD) method is used to provide a reliable forecasting of tumor ablation treatment simulation in real time, which is quite needed in medical practice. To achieve this, an extended Pennes bioheat model must be employed, taking into account both the water evaporation phenomenon and the tissue damage during tumor ablation. Methods: A meshless point collocation solver is used for the numerical solution of the governing equations. The results obtained are used by the DMD method for forecasting the numerical solution faster than the meshless solver. The procedure is first validated against analytical and numerical predictions for simple problems. The DMD method is then applied to three-dimensional simulations that involve modeling of tumor ablation and account for metabolic heat generation, blood perfusion, and heat ablation using realistic values for the various parameters. Results: The present method offers very fast numerical solution to bioheat transfer, which is of clinical significance in medical practice. It also sidesteps the mathematical treatment of boundaries between tumor and healthy tissue, which is usually a tedious procedure with some inevitable degree of approximation. The DMD method provides excellent predictions of the temperature profile in tumors and in the healthy parts of the tissue, for linear and nonlinear thermal properties of the tissue. Conclusions: The low computational cost renders the use of DMD suitable forin situ real time tumor ablation simulations without sacrificing accuracy. In such a way, the tumor ablation treatment planning is feasible using just a personal computer thanks to the simplicity of the numerical procedure used. The geometrical data can be provided directly by medical image modalities used in everyday practice. © 2014 American Association of Physicists in Medicine.

Experimental study on ablating goat liver tissue with ultrasound imaging guided percutaneous irreversible electroporation

Directory of Open Access Journals (Sweden)

Ying LIU

2011-03-01

Full Text Available Objective To investigate the proper method of percutaneous irreversible electroporation(IRE to ablate goat liver tissue under ultrasonic guidance,and observe the features of ultrasound imaging and histological changes.Methods The pulse electric fields(PEFs with permanent duration(100 μs,frequency(1Hz,voltage(2000V and pulses(120 pieces were applied to the electrodes,and the electrodes were placed into goats’ liver under ultrasound guidance through the animal skin to the target area.The treated area was observed by real-time ultrasound scanning,and the histopathological changes were assessed by hematoxylin and eosin(HE staining under light microscope at the time of 0h and 24h after IRE ablation.The circumscribed ablated area was compared with that of finite element modeling(FEM calculation method.Results Ultrasound imaging guidance was accurate in focusing on the target area.Imaging captured by the ultrasound after IRE procedure was quite different from that of the normal liver imaging.Complete hepatic cell death with a sharp demarcation between the ablated zone and the non-ablated zone was well visualized 24 hours after the procedure.Necrospy-based measurement demonstrated a high consistence with FEM-anticipated ablation zones.Conclusion With real-time monitoring by ultrasonography and well-controlled ablation of the target tissue,percutaneous IRE can provide a novel and unique ablative method for cancer treatment.The present paper provides a fundamental experimental work for future studies on clinical application of IRE.

Blind rats are not profoundly impaired in the reference memory Morris water maze and cannot be clearly discriminated from rats with cognitive deficits in the cued platform task.

Science.gov (United States)

Lindner, M D; Plone, M A; Schallert, T; Emerich, D F

1997-06-01

The Morris water maze is commonly used to test cognitive function in rodent models of neurological disorders including age-related cognitive deficits. It is often assumed that the most profoundly impaired aged rats may be blind due to retinal degeneration, and it has been reported that animals with visual sensory deficits can be identified based on their performance in a cued platform task. The results of the present study demonstrate that blind rats can perform surprisingly well in the reference memory version of the Morris water maze, and that blind rats cannot be selectively excluded based on performance in the cued platform task since atropine-treated rats also perform poorly in the cued platform task. Future studies may be able to develop screening procedures that help to eliminate subjects with non-cognitive deficits, but the present results do not support the use of the cued platform or straight swim task as screening procedures. Experimenters must be careful to consider the role that visual sensory function and other non-cognitive factors may have in performance of the spatial learning Morris water maze, and also the role that severe cognitive deficits may have in performance of the cued platform task.

Radiofrequency ablation of pulmonary metastasis from colorectal cancer - follow up radiological appearances and results

International Nuclear Information System (INIS)

Chai, D.; Glenn, D.

2002-01-01

Full text: Tumour ablation with radiofrequency (RF) energy is a relatively new procedure for the treatment of focal malignant disease. Several published trials show the benefit of this procedure in the treatment of malignant liver lesions, however, there are few trials on the benefits of treating pulmonary metastases in this way. The first 14 patients having RF ablation of pulmonary metastases from colorectal cancer (CRC) have been followed. 11 had their RF ablation performed at St George Public Hospital under CT fluoroscopy, 3 under fluoroscopy at St George Private Hospital. Complications from the procedure are described, as well as follow up appearances and results. The only significant complications described so far are five pneumothoraces, three requiring treatment with one needing extended hospital admission. Intraprocedural parenchymal haemorrhage, and changes of consolidation in surrounding lung not causing significant clinical symptoms were also found. One case of post procedure pneumonia occurred. Minor haemoptysis also occurred. Successfully ablated lesions show and increase in size in the one week and one month CT scans, but then progressively fall in size. Some show cavitation, which resolves. No significant detrimental impact on quality of life has so far been found, but medium and long-term effects are yet to be studied. RF ablation of pulmonary metastases from CRC, while still at its early stages, shows promise as a possible second line treatment (with other adjuvant therapy) for the management of focal malignant disease in the lung. CT fluoroscopy/fluoroscopy is a viable method for electrode placement and is performed this way at our institution. Copyright (2002) Blackwell Science Pty Ltd

Navigation using sensory substitution in real and virtual mazes.

Directory of Open Access Journals (Sweden)

Daniel-Robert Chebat

Full Text Available Under certain specific conditions people who are blind have a perception of space that is equivalent to that of sighted individuals. However, in most cases their spatial perception is impaired. Is this simply due to their current lack of access to visual information or does the lack of visual information throughout development prevent the proper integration of the neural systems underlying spatial cognition? Sensory Substitution devices (SSDs can transfer visual information via other senses and provide a unique tool to examine this question. We hypothesize that the use of our SSD (The EyeCane: a device that translates distance information into sounds and vibrations can enable blind people to attain a similar performance level as the sighted in a spatial navigation task. We gave fifty-six participants training with the EyeCane. They navigated in real life-size mazes using the EyeCane SSD and in virtual renditions of the same mazes using a virtual-EyeCane. The participants were divided into four groups according to visual experience: congenitally blind, low vision & late blind, blindfolded sighted and sighted visual controls. We found that with the EyeCane participants made fewer errors in the maze, had fewer collisions, and completed the maze in less time on the last session compared to the first. By the third session, participants improved to the point where individual trials were no longer significantly different from the initial performance of the sighted visual group in terms of errors, time and collision.

Laser Guidance in C-Arm Cone-Beam CT-Guided Radiofrequency Ablation of Osteoid Osteoma Reduces Fluoroscopy Time

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Kroes, Maarten W., E-mail: Maarten.Kroes@radboudumc.nl; Busser, Wendy M. H.; Hoogeveen, Yvonne L.; Lange, Frank de; Schultze Kool, Leo J. [Radboud University Medical Center, Department of Radiology and Nuclear Medicine (Netherlands)

2017-05-15

PurposeTo assess whether laser guidance can reduce fluoroscopy and procedure time of cone-beam computed tomography (CBCT)-guided radiofrequency (RF) ablations of osteoid osteoma compared to freehand CBCT guidance.Materials and Methods32 RF ablations were retrospectively analyzed, 17 laser-guided and 15 procedures using the freehand technique. Subgroup selection of 18 ablations in the hip–pelvic region with a similar degree of difficulty was used for a direct comparison. Data are presented as median (ranges).ResultsComparison of all 32 ablations resulted in fluoroscopy times of 365 s (193–878 s) for freehand and 186 s (75–587 s) for laser-guided procedures (p = 0.004). Corresponding procedure times were 56 min (35–97 min) and 52 min (30–85 min) (p = 0.355). The subgroup showed comparable target sizes, needle path lengths, and number of scans between groups. Fluoroscopy times were lower for laser-guided procedures, 215 s (75–413 s), compared to 384 s (193–878 s) for freehand (p = 0.012). Procedure times were comparable between groups, 51 min (30–72 min) for laser guidance and 58 min (35–79 min) for freehand (p = 0.172).ConclusionAdding laser guidance to CBCT-guided osteoid osteoma RF ablations significantly reduced fluoroscopy time without increasing procedure time.Level of EvidenceLevel 4, case series.

Factors associated with initial incomplete ablation for benign thyroid nodules after radiofrequency ablation: First results of CEUS evaluation.

Science.gov (United States)

Zhao, Chong-Ke; Xu, Hui-Xiong; Lu, Feng; Sun, Li-Ping; He, Ya-Ping; Guo, Le-Hang; Li, Xiao-Long; Bo, Xiao-Wan; Yue, Wen-Wen

2017-01-01

To assess the factors associated with initial incomplete ablation (ICA) after radiofrequency ablation for benign thyroid nodules (BTNs). 69 BTNs (mean volume 6.35±5.66 ml, range 1.00-25.04 ml) confirmed by fine-needle aspiration cytology (FNAC) in fifty-four patients were treated with ultrasound-guided percutaneous radiofrequency ablation (RFA) and the local treatment efficacy was immediately assessed by intra-procedural contrast-enhanced ultrasound (CEUS). The RFA was performed with a bipolar electrode (CelonProSurge 150-T20, output power: 20 W). CEUS was performed with a second generation contrast agent under low acoustic power (i.e. coded phase inversion, CPI). Characteristics of clinical factors, findings on conventional gray-scale ultrasound, color-Doppler ultrasound, and CEUS were evaluated preoperatively. Factors associated with initial ICA and initial ICA patterns on CEUS were assessed. Volume reduction ratios (VRRs) of ICA nodules were compared with those with complete ablation (CA). The RFA procedures were accomplished with a mean ablation time and mean total energy deposition of 11.13±3.39 min (range, 5.38-22.13 min) and 12612±4466 J (range, 6310-26130 J) respectively. CEUS detected initial ICA in 21 of 69 (30.8%) BTNs and 16 (76.2%) of the 21 BTNs with initial ICA achieved CA after additional RFA, leading to a final CA rate of 92.8% (64/69). The factors associated with initial ICA were predominantly solid nodule, nodule close to danger triangle area, nodule close to carotid artery, and peripheral blood flow on color-Doppler ultrasound (all P 50% at the 6-month follow-up, among which 7 nodules (10.1%) had VRRs of >90%. There were significant differences in VRRs between ICA nodules and CA nodules at the 3- and 6-month follow-up (all P ultrasound. CEUS assists quick treatment response evaluation and facilitates subsequent additional RFA and final CA of the nodules. Nodules with CA achieve a better outcome in terms of VRR in comparison with

Clinical impact of an open-irrigated radiofrequency catheter with direct force measurement on atrial fibrillation ablation.

Science.gov (United States)

Martinek, Martin; Lemes, Christine; Sigmund, Elisabeth; Derndorfer, Michael; Aichinger, Josef; Winter, Siegmund; Nesser, Hans-Joachim; Pürerfellner, Helmut

2012-11-01

Electrode-tissue contact is crucial for adequate lesion formation in radiofrequency catheter ablation (RFCA). We assessed the impact of direct catheter force measurement on acute procedural parameters during RFCA of atrial fibrillation (AF). Fifty consecutive patients (28 male) with paroxysmal AF who underwent their first procedure of circumferential pulmonary vein (PV) isolation (PVI) were assigned to either RFCA using (1) a standard 3.5-mm open-irrigated-tip catheter or (2) a catheter with contact force measurement capabilities. Using the endpoint of PVI with entry and exit block, acute procedural parameters were assessed. Procedural data showed a remarkable decline in ablation time (radiofrequency time needed for PVI) from 50.5 ± 15.9 to 39.0 ± 11.0 minutes (P = 0.007) with a reduction in overall procedure duration from 185 ± 46 to 154 ± 39 minutes (P = 0.022). In parallel, the total energy delivered could be significantly reduced from 70,926 ± 19,470 to 58,511 ± 14,655 Ws (P = 0.019). The number of acute PV reconnections declined from 36% to 12% (P = 0.095). The use of contact force sensing technology is able to significantly reduce ablation and procedure times in PVI. In addition, energy delivery is substantially reduced by avoiding radiofrequency ablation in positions with insufficient surface contact. Procedural efficacy and safety of this new feature have to be evaluated in larger cohorts. ©2012, The Authors. Journal compilation ©2012 Wiley Periodicals, Inc.

Percutaneous radiofrequency ablation of hepatocellular carcinoma: analysis of 80 patients treated with two consecutive sessions

International Nuclear Information System (INIS)

Rhim, Hyunchul; Kim, Young-sun; Choi, Dongil; Lim, Hyo K.; Park, KoWoon

2008-01-01

This study investigated the reasons for some patients requiring two consecutive sessions of percutaneous radiofrequency (RF) ablation of hepatocellular carcinoma (HCC). We reviewed our database of 1,179 patients (1,624 treatments) with HCCs treated by percutaneous ultrasound (US)-guided RF ablation over 6 years. We retrospectively evaluated 80 patients who required a second session after the first session. The medical records and follow-up CTs were studied. We assessed the reasons for the second session and the patient outcomes. A second session was required in 80 (4.8%) out of 1,642 treatments of percutaneous RF ablation for HCC. The reason for the second session included technical failure related to the patient or the procedure (n=26), technical failure due to residual (n=40), newly detected (n=11) or missed (n=3) tumors found at the immediate follow-up CT. All patients were retreated with a second RFA session the next day. Seventy-five (93%) of 80 patients achieved complete ablation after the second session. The remaining five patients were treated by TACE (n=1), additional RFA (as second treatment at next admission) (n=3), or were lost to follow-up (n=1). After 1 month follow-up, 72 patients (96%) showed complete ablation after the second session. The interventional oncologist should understand the technical reasons for a patient requiring a second session of RF ablation when providing treatment for HCCs and perform careful pre-procedural planning to minimize the need for multi-session procedures. (orig.)

Palliative Treatment of Rectal Carcinoma Recurrence Using Radiofrequency Ablation

Energy Technology Data Exchange (ETDEWEB)

Mylona, Sophia, E-mail: mylonasophia@yahoo.com; Karagiannis, Georgios, E-mail: gekaragiannis@yahoo.gr; Patsoura, Sofia, E-mail: sofia.patsoura@yahoo.gr [Hellenic Red Cross Hospital ' Korgialenio-Benakio' (Greece); Galani, Panagiota, E-mail: gioulagalani@yahoo.com [Amalia Fleming Hospital (Greece); Pomoni, Maria, E-mail: marypomoni@gmail.com [Evgenidion Hospital (Greece); Thanos, Loukas, E-mail: loutharad@yahoo.com [Sotiria Hospital (Greece)

2012-08-15

Purpose: To evaluate the safety and efficacy of CT-guided radiofrequency (RF) ablation for the palliative treatment of recurrent unresectable rectal tumors. Materials and Methods: Twenty-seven patients with locally recurrent rectal cancer were treated with computed tomography (CT)-guided RF ablation. Therapy was performed with the patient under conscious sedation with a seven- or a nine-array expandable RF electrode for 8-10 min at 80-110 Degree-Sign C and a power of 90-110 W. All patients went home under instructions the next day of the procedure. Brief Pain Inventory score was calculated before and after (1 day, 1 week, 1 month, 3 months, and 6 months) treatment. Results: Complete tumor necrosis rate was 77.8% (21 of a total 27 procedures) despite lesion location. BPI score was dramatically decreased after the procedure. The mean preprocedure BPI score was 6.59, which decreased to 3.15, 1.15, and 0.11 at postprocedure day 1, week 1, and month 1, respectively, after the procedure. This decrease was significant (p < 0.01 for the first day and p < 0.001 for the rest of the follow-up intervals (paired Student t test; n - 1 = 26) for all periods during follow-up. Six patients had partial tumor necrosis, and we were attempted to them with a second procedure. Although the necrosis area showed a radiographic increase, no complete necrosis was achieved (secondary success rate 65.6%). No immediate or delayed complications were observed. Conclusion: CT-guided RF ablation is a minimally invasive, safe, and highly effective technique for treatment of malignant rectal recurrence. The method is well tolerated by patients, and pain relief is quickly achieved.

Percutaneous thermal ablation of renal neoplasms; Perkutane Thermoablation von Nierentumoren

Energy Technology Data Exchange (ETDEWEB)

Tacke, J. [Inst. fuer Diagnostische und Interventionelle Radiologie/Neuroradiologie, Klinikum Passau (Germany); Mahnken, A.H.; Guenther, R.W. [Klinik fuer Radiologische Diagnostik, Universitaetsklinikum Aachen (Germany)

2005-12-15

Due to modern examination techniques such as multidetector computed tomography and high-field magnetic resonance imaging, the detection rate of renal neoplasms is continually increasing. Even though tumors exceeding 4 cm in diameter rarely metastasize, all renal lesions that are possible neoplasms should be treated. Traditional treatment techniques include radical nephrectomy or nephron-sparing resection, which are increasingly performed laparoscopically. Modern thermal ablation techniques such as hyperthermal techniques like radiofrequency ablation RFA, laser induced thermal ablation LITT, focused ultrasound FUS and microwave therapy MW, as well as hypothermal techniques (cryotherapy) may be a useful treatment option for patients who are unfit for or refuse surgical resection. Cryotherapy is the oldest and best known thermal ablation technique and can be performed laparoscopically or percutaneously. Since subzero temperatures have no antistyptic effect, additional maneuvers must be performed to control bleeding. Percutaneous cryotherapy of renal tumors is a new and interesting method, but experience with it is still limited. Radiofrequency ablation is the most frequently used method. Modern probe design allows volumes between 2 and 5 cm in diameter to be ablated. Due to hyperthermal tract ablation, the procedure is deemed to be safe and has a low complication rate. Although there are no randomized comparative studies to open resection, the preliminary results for renal RFA are promising and show RFA to be superior to other thermal ablation techniques. Clinical success rates are over 90% for both, cryo- and radiofrequency ablation. Whereas laser induced thermal therapy is established in hepatic ablation, experience is minimal with respect to renal application. For lesions of more than 2 cm in diameter, additional cooling catheters are required. MR thermometry offers temperature control during ablation. Microwave ablation is characterized by small ablation volumes

Image-guided focused ultrasound ablation of breast cancer: current status, challenges, and future directions

NARCIS (Netherlands)

Schmitz, A.C.; Gianfelice, D.; Daniel, B.L.; Mali, W.P.T.M.; Bosch, M.A.A.J. van den

2008-01-01

Image-guided focussed ultrasound (FUS) ablation is a noninvasive procedure that has been used for treatment of benign or malignant breast tumours. Image-guidance during ablation is achieved either by using real-time ultrasound (US) or magnetic resonance imaging (MRI). The past decade phase I

Activation of the hippocampal complex during tactile maze solving in congenitally blind subjects

DEFF Research Database (Denmark)

Gagnon, Léa; Schneider, Fabien C; Siebner, Hartwig R

2012-01-01

Despite their lack of vision, congenitally blind subjects are able to build and manipulate cognitive maps for spatial navigation. It is assumed that they thereby rely more heavily on echolocation, proprioceptive signals and environmental cues such as ambient temperature and audition to compensate...... imaging (fMRI) in congenitally blind and blindfolded sighted participants while they navigated through a tactile multiple T-maze. Both groups learned the maze task at a similar pace. In blind participants, tactile maze navigation was associated with increased BOLD responses in the right hippocampus...

Impact of radiofrequency ablation geometry on electrical conduction

Science.gov (United States)

Rivas, Rhiana N.; Lye, Theresa H.; Hendon, Christine P.

2018-02-01

The gold standard of current treatment for atrial fibrillation is radiofrequency ablation (RFA). Single RFA procedures have low long-term, single-procedure success rates, which can be attributed to factors including inability to measure and visualize lesion depth in real time and incomplete knowledge of how atrial fibrillation manifests and persists. One way to address this problem is to develop a heart model that accurately fits lesion dimensions and depth using OCT to extract structural information. Twenty-three lesions of varying transmurality in left and right swine atrial tissue have been imaged with a Thorlabs OCT system with 6.5-micron axial resolution and a custom Ultra High Resolution system with 2.5-micron axial resolution. The boundaries of the ablation lesions were identified by the appearance of the birefringence artifact to identify areas of un-ablated tissue, as well as by changes to depth penetration and structural features, including decreased contrast between the endocardium and myocardium and disappearance of collagen fibers within the ablation lesion. Using these features, the lateral positions of the lesion boundaries were identified. An algorithm that fit ellipses to the lesion contours modeled the ablation geometry in depth. Lesion dimensions and shape were confirmed by comparison with trichrome histological processing. Finite-element models were fitted with these parameters and electrophysiological simulations were run with the Continuity 6 package. Next steps include correlating lesion geometry to conduction velocity, and including further tissue complexity such as varying tissue composition and fiber orientation. Additional models of linear lesions with gaps and adjacent lesions created with non-perpendicular contact will be created. This work will provide insight into how lesion geometry, tissue composition, and fiber organization impact electrophysiological propagation.

Mathematical methods to model rodent behavior in the elevated plus-maze.

Science.gov (United States)

Arantes, Rafael; Tejada, Julián; Bosco, Geraldine G; Morato, Silvio; Roque, Antonio C

2013-11-15

The elevated plus maze is a widely used experimental test to study anxiety-like rodent behavior. It is made of four arms, two open and two closed, connected at a central area forming a plus shaped maze. The whole apparatus is elevated 50 cm from the floor. The anxiety of the animal is usually assessed by the number of entries and duration of stay in each arm type during a 5-min period. Different mathematical methods have been proposed to model the mechanisms that control the animal behavior in the maze, such as factor analysis, statistical inference on Markov chains and computational modeling. In this review we discuss these methods and propose possible extensions of them as a direction for future research. Copyright © 2013 Elsevier B.V. All rights reserved.

Preoperative study of the surface ECG for the prognosis of atrial fibrillation maze surgery outcome at discharge

International Nuclear Information System (INIS)

Hernández, Antonio; Rieta, José Joaquín; Alcaraz, Raúl; Hornero, Fernando

2014-01-01

The Cox-maze surgery is an effective procedure for terminating atrial fibrillation (AF) in patients requiring open-heart surgery associated with another heart disease. After the intervention, regardless of the patient's rhythm, all are treated with oral anticoagulants and antiarrhythmic drugs prior to discharge. Furthermore, patients maintaining AF before discharge could also be treated with electrical cardioversion (ECV). In view of this, a preoperative prognosis of the patient's rhythm at discharge would be helpful for optimizing drug therapy planning as well as for advancing ECV therapy. This work analyzes 30 preoperative electrocardiograms (ECGs) from patients suffering from AF in order to predict the Cox-maze surgery outcome at discharge. Two different characteristics of the AF pattern have been studied. On the one hand, the atrial activity (AA) organization, which provides information about the number of propagating wavelets in the atria, was investigated. AA organization has been successfully used in previous studies related to spontaneous reversion of paroxysmal AF and to the outcome of ECV. To assess organization, the dominant atrial frequency (DAF) and sample entropy (SampEn) have been computed. On the other hand, the second characteristic studied was the fibrillatory wave (f-wave) amplitude, which has been demonstrated to be a valuable indicator of the Cox-maze surgery outcome in previous studies. Moreover, this parameter has been obtained through a new methodology, based on computing the f-wave average power (fWP). Finally, all the computed indices were combined in a decision tree in order to improve prediction capability. Results for the DAF yielded a sensitivity (Se), a specificity (Sp) and an accuracy (Acc) of 61.54%, 82.35% and 73.33%, respectively. For SampEn the values were 69.23%, 76.00% and 73.33%, respectively, and for fWP they were 92.31%, 82.35% and 86.67%, respectively. Finally, the decision tree combining the three parameters

Effects of Amphetamine and β-Endorphin Fragments on Maze Performance in Rats

NARCIS (Netherlands)

Boer, S. de; Bohus, B.

1990-01-01

Fragments of β-endorphin and amphetamine cause similar effects in some tests of maze behavior in rats. The present study served to compare the influence of amphetamine and two β-endorphin fragments [β-endorphin (βE)-(2-9) and βE-(2-16)] on maze behavior in more detail. In Experiment I no significant

Lesion size in relation to ablation site during radiofrequency ablation

DEFF Research Database (Denmark)

Petersen, H H; Chen, X; Pietersen, A

1998-01-01

This study was designed to investigate the effect of the convective cooling of the tip of the ablation electrode during temperature controlled radiofrequency ablation. In vivo two different application sites in the left ventricle of anaesthetised pigs were ablated and in vitro ablation was perfor......This study was designed to investigate the effect of the convective cooling of the tip of the ablation electrode during temperature controlled radiofrequency ablation. In vivo two different application sites in the left ventricle of anaesthetised pigs were ablated and in vitro ablation...... was performed during two different flow-velocities in a tissue bath, while electrode contact pressure and position were unchanged. Target temperature was 80 degrees C. Obtained tip temperature, power consumption and lesion dimensions were measured. In vivo lesion volume, depth and width were found significantly.......61 in vitro). We conclude that during temperature controlled radiofrequency ablation lesion size differs for septal and apical left ventricular applications. Differences in convective cooling might play an important role in this respect. This is supported by our in vitro experiments, where increased...

12-month efficacy of a single radiofrequency ablation on autonomously functioning thyroid nodules.

Science.gov (United States)

Bernardi, Stella; Stacul, Fulvio; Michelli, Andrea; Giudici, Fabiola; Zuolo, Giulia; de Manzini, Nicolò; Dobrinja, Chiara; Zanconati, Fabrizio; Fabris, Bruno

2017-09-01

Radiofrequency ablation has been advocated as an alternative to radioiodine and/or surgery for the treatment of autonomously functioning benign thyroid nodules. However, only a few studies have measured radiofrequency ablation efficacy on autonomously functioning benign thyroid nodules. The aim of this work was to evaluate the 12-month efficacy of a single session of radiofrequency ablation (performed with the moving shot technique) on solitary autonomously functioning benign thyroid nodules. Thirty patients with a single, benign autonomously functioning benign thyroid nodules, who were either unwilling or ineligible to undergo surgery and radioiodine, were treated with radiofrequency ablation between April 2012 and May 2015. All the patients underwent a single radiofrequency ablation, performed with the 18-gauge needle and the moving shot technique. Clinical, laboratory, and ultrasound evaluations were scheduled at baseline, and after 1, 3, 6, and 12 months from the procedure. A single radiofrequency ablation reduced thyroid nodule volume by 51, 63, 69, and 75 % after 1, 3, 6, and 12 months, respectively. This was associated with a significant improvement of local cervical discomfort and cosmetic score. As for thyroid function, 33 % of the patients went into remission after 3 months, 43 % after 6 months, and 50 % after 12 months from the procedure. This study demonstrates that a single radiofrequency ablation allowed us to withdraw anti-thyroid medication in 50 % of the patients, who remained euthyroid afterwards. This study shows that a single radiofrequency ablation was effective in 50 % of patients with autonomously functioning benign thyroid nodules. Patients responded gradually to the treatment. It is possible that longer follow-up studies might show greater response rates.

Risk of Ionizing Radiation in Women of Childbearing Age undergoing Radiofrequency Ablation

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Lima, Gustavo Glotz de, E-mail: gglima.pesquisa@gmail.com; Gomes, Daniel Garcia; Gensas, Caroline Saltz; Simão, Mariana Fernandez; Rios, Matheus N.; Pires, Leonardo Martins; Kruse, Marcelo Lapa; Leiria, Tiago Luiz Luz [Instituto de Cardiologia, Fundação Universitária de Cardiologia, Porto Alegre, RS (Brazil)

2013-11-15

The International Commission of Radiology recommends a pregnancy screening test to all female patients of childbearing age who will undergo a radiological study. Radiation is known to be teratogenic and its effect is cumulative. The teratogenic potential starts at doses close to those used during these procedures. The prevalence of positive pregnancy tests in patients undergoing electrophysiological studies and/or catheter ablation in our midst is unknown. To evaluate the prevalence of positive pregnancy tests in female patients referred for electrophysiological study and/or radiofrequency ablation. Cross-sectional study analyzing 2,966 patients undergoing electrophysiological study and/or catheter ablation, from June 1997 to February 2013, in the Institute of Cardiology of Rio Grande do Sul. A total of 1490 procedures were performed in women, of whom 769 were of childbearing age. All patients were screened with a pregnancy test on the day before the procedure. Three patients tested positive, and were therefore unable to undergo the procedure. The prevalence observed was 3.9 cases per 1,000 women of childbearing age. Because of their safety and low cost, pregnancy screening tests are indicated for all women of childbearing age undergoing radiological studies, since the degree of ionizing radiation needed for these procedures is very close to the threshold for teratogenicity, especially in the first trimester, when the signs of pregnancy are not evident.

Risk of Ionizing Radiation in Women of Childbearing Age undergoing Radiofrequency Ablation

International Nuclear Information System (INIS)

Lima, Gustavo Glotz de; Gomes, Daniel Garcia; Gensas, Caroline Saltz; Simão, Mariana Fernandez; Rios, Matheus N.; Pires, Leonardo Martins; Kruse, Marcelo Lapa; Leiria, Tiago Luiz Luz

2013-01-01

The International Commission of Radiology recommends a pregnancy screening test to all female patients of childbearing age who will undergo a radiological study. Radiation is known to be teratogenic and its effect is cumulative. The teratogenic potential starts at doses close to those used during these procedures. The prevalence of positive pregnancy tests in patients undergoing electrophysiological studies and/or catheter ablation in our midst is unknown. To evaluate the prevalence of positive pregnancy tests in female patients referred for electrophysiological study and/or radiofrequency ablation. Cross-sectional study analyzing 2,966 patients undergoing electrophysiological study and/or catheter ablation, from June 1997 to February 2013, in the Institute of Cardiology of Rio Grande do Sul. A total of 1490 procedures were performed in women, of whom 769 were of childbearing age. All patients were screened with a pregnancy test on the day before the procedure. Three patients tested positive, and were therefore unable to undergo the procedure. The prevalence observed was 3.9 cases per 1,000 women of childbearing age. Because of their safety and low cost, pregnancy screening tests are indicated for all women of childbearing age undergoing radiological studies, since the degree of ionizing radiation needed for these procedures is very close to the threshold for teratogenicity, especially in the first trimester, when the signs of pregnancy are not evident

Epiphysiodesis Made with Radio Frequency Ablation: First Results From a Pilot Study

DEFF Research Database (Denmark)

Shiguetomi Medina, Juan Manuel; Gottliebsen, Martin; Rahbek, Ole

for a reliable and precise procedure which overcomes the complications. Development of a new technique for epiphysiodesis using radiofrequency ablation on an animal model that involves less scarring, less exposure to X-rays, and reduces the risk of injuring the surrounding structures compared to current methods...... the procedure and 12 weeks later. The length of both tibiae was measured. Both legs were equal at the beginning of the study and there was a leg length difference of around 4mm at the end. No damage to the surrounding cartilage structures was found. Epiphysiodesis using radio frequency ablation is an innovative...

Measurement of intrahepatic pressure during radiofrequency ablation in porcine liver.

Science.gov (United States)

Kawamoto, Chiaki; Yamauchi, Atsushi; Baba, Yoko; Kaneko, Keiko; Yakabi, Koji

2010-04-01

To identify the most effective procedures to avoid increased intrahepatic pressure during radiofrequency ablation, we evaluated different ablation methods. Laparotomy was performed in 19 pigs. Intrahepatic pressure was monitored using an invasive blood pressure monitor. Radiofrequency ablation was performed as follows: single-step standard ablation; single-step at 30 W; single-step at 70 W; 4-step at 30 W; 8-step at 30 W; 8-step at 70 W; and cooled-tip. The array was fully deployed in single-step methods. In the multi-step methods, the array was gradually deployed in four or eight steps. With the cooled-tip, ablation was performed by increasing output by 10 W/min, starting at 40 W. Intrahepatic pressure was as follows: single-step standard ablation, 154.5 +/- 30.9 mmHg; single-step at 30 W, 34.2 +/- 20.0 mmHg; single-step at 70 W, 46.7 +/- 24.3 mmHg; 4-step at 30 W, 42.3 +/- 17.9 mmHg; 8-step at 30 W, 24.1 +/- 18.2 mmHg; 8-step at 70 W, 47.5 +/- 31.5 mmHg; and cooled-tip, 114.5 +/- 16.6 mmHg. The radiofrequency ablation-induced area was spherical with single-step standard ablation, 4-step at 30 W, and 8-step at 30 W. Conversely, the ablated area was irregular with single-step at 30 W, single-step at 70 W, and 8-step at 70 W. The ablation time was significantly shorter for the multi-step method than for the single-step method. Increased intrahepatic pressure could be controlled using multi-step methods. From the shapes of the ablation area, 30-W 8-step expansions appear to be most suitable for radiofrequency ablation.

The first clinical application of planning software for laparoscopic microwave thermosphere ablation of malignant liver tumours.

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Berber, Eren

2015-07-01

Liver tumour ablation is an operator-dependent procedure. The determination of the optimum needle trajectory and correct ablation parameters could be challenging. The aim of this study was to report the utility of a new, procedure planning software for microwave ablation (MWA) of liver tumours. This was a feasibility study in a pilot group of five patients with nine metastatic liver tumours who underwent laparoscopic MWA. Pre-operatively, parameters predicting the desired ablation zones were calculated for each tumour. Intra-operatively, this planning strategy was followed for both antenna placement and energy application. Post-operative 2-week computed tomography (CT) scans were performed to evaluate complete tumour destruction. The patients had an average of two tumours (range 1-4), measuring 1.9 ± 0.4 cm (range 0.9-4.4 cm). The ablation time was 7.1 ± 1.3 min (range 2.5-10 min) at 100W. There were no complications or mortality. The patients were discharged home on post-operative day (POD) 1. At 2-week CT scans, there were no residual tumours, with a complete ablation demonstrated in all lesions. This study describes and validates pre-treatment planning software for MWA of liver tumours. This software was found useful to determine precisely the ablation parameters and needle placement to create a predicted zone of ablation. © 2015 International Hepato-Pancreato-Biliary Association.

Pelvic denervation procedures for dysmenorrhea.

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Ramirez, Christina; Donnellan, Nicole

2017-08-01

Chronic pelvic pain and dysmenorrhea are common conditions affecting reproductive-age women. Surgical pelvic denervation procedures may be a treatment option for women with midline dysmenorrhea, in which medical management is declined by the patient, ineffective at managing symptoms, or medically contraindicated. This review describes the surgical techniques and complications associated with pelvic denervation procedures as well as the current evidence for these procedures in women with primary dysmenorrhea and dysmenorrhea secondary to endometriosis. Presacral neurectomy is the preferred pelvic denervation procedure in patients with primary dysmenorrhea and midline chronic pelvic pain associated with endometriosis. In patients with endometriosis presacral neurectomy is a useful adjunct to excision or ablation of all endometrial lesions to improve postoperative pain relief. There is no additional patient benefit of performing combined presacral neurectomy and uterine nerve ablation procedures. Pelvic denervation procedures can be performed safely and quickly with a low risk of complication if the surgeon is knowledgeable and skilled in operating in the presacral space. Patients should be adequately counseled on expected success rates and potential complications associated with pelvic denervation procedures.

Effects of rolipram and zaprinast on learning and memory in the Morris water maze and radial arm maze tests in naive mice.

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Akar, F; Mutlu, O; Celikyurt, I K; Ulak, G; Erden, F; Bektas, E; Tanyeri, P

2015-02-01

Inhibition of phosphodiesterase 5 (PDE) improved recognition memory and counteracted spatial learning impairment induced by nitric oxide synthase (NOS) inhibition in recent studies. Aim of this study was to investigate effects of rolipram, a PDE4 inhibitor and zaprinast, a PDE5 inhibitor, on learning and memory in Morris water maze (MWM) and radial arm maze (RAM) tests in naive mice. Male Balb-c mice were treated subchronically with zaprinast (3 and 10 mg/kg) and rolipram (0.05 and 0.1 mg/kg) for 6 days in the MWM test and acutely before the retention trial of radial arm maze test. Rolipram (0.05 and 0.1 mg/kg) significantly decreased escape latency between 2(nd) and 5(th) sessions, while zaprinast (10 mg/kg) significantly decreased escape latency only in 2(nd) session. Rolipram (0.05 and 0.1 mg/kg) and zaprinast (10 mg/kg) significantly increased time spent in escape platform's quadrant in probe trial of MWM test; only rolipram decreased mean distance to platform, while zaprinast had no effect on mean distance to platform. Zaprinast (3 and 10 mg/kg) significantly decreased number of errors compared to control group, while rolipram (0.05 and 0.1mg/kg) had no effect on number of errors in retention trial of RAM test. Rolipram (0.05 and 0.1 mg/kg) and zaprinast (10 mg/kg) significantly decreased time spent to complete retention trial (latency) compared to control group. Our study revealed that both zaprinast and rolipram enhanced spatial memory in MWM, while zaprinast seems to have more memory enhancing effects compared to rolipram in radial arm maze test. © Georg Thieme Verlag KG Stuttgart · New York.

What does the CBM-maze test measure?

NARCIS (Netherlands)

Muijselaar, M.M.L.; Kendeou, P.; de Jong, P.F.; van den Broek, P.W.

2017-01-01

In this study, we identified the code-related (decoding, fluency) and language comprehension (vocabulary, listening comprehension) demands of the CBM-Maze test, a formative assessment, and compared them to those of the Gates–MacGinitie test, a standardized summative assessment. The demands of these

Younger apes and human children plan their moves in a maze task.

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Völter, Christoph J; Call, Josep

2014-02-01

Planning defined as the predetermination of a sequence of actions towards some goal is crucial for complex problem solving. To shed light on the evolution of executive functions, we investigated the ontogenetic and phylogenetic origins of planning. Therefore, we presented all four great apes species (N=12) as well as 4- and 5-year-old human preschoolers (N=24) with a vertical maze task. To gain a reward placed on the uppermost level of the maze, subjects had to move the reward to the bottom through open gaps situated at each level of the maze. In total, there were ten gaps located over three of the maze's levels, and free passage through these gaps could be flexibly blocked using multiple traps. Due to the decision tree design of the maze, the subjects had to plan their actions depending on the trap configuration up to two steps ahead to successfully retrieve the reward. We found that (1) our measure of planning was negatively correlated with age in nonhuman apes, (2) younger apes as well as 5-year-old children planned their moves up to two steps ahead whereas 4-year-olds were limited to plan one step ahead, and (3) similar performance but different underlying limitations between apes and children. Namely, while all species of nonhuman apes were limited by a lack of motor control, human children exhibited a shortage in shifting their attention across a sequence of subgoals. Copyright © 2013 Elsevier B.V. All rights reserved.

Therapeutic efficacy of percutaneous radiofrequency ablation versus microwave ablation for hepatocellular carcinoma.

Directory of Open Access Journals (Sweden)

Lei Zhang

Full Text Available The aim of this study was to investigate the therapeutic efficacy of percutaneous radiofrequency (RF ablation versus microwave (MW ablation for hepatocellular carcinoma (HCC measuring ≤ 5 cm in greatest diameter. From January 2006 to December 2006, 78 patients had undergone RF ablation whereas 77 had undergone MW ablation. Complete ablation (CA, local tumour progression (LTP and distant recurrence (DR were compared. The overall survival curves were calculated with the Kaplan-Meier technique and compared with the log-rank test. The CA rate was 83.4% (78/93 for RF ablation and 86.7%(91/105 for MW ablation. The LTP rate was 11.8% (11/93 for RF ablation and 10.5% (11/105 for MW ablation. DR was found in 51 (65.4% in the RF ablation and 62 (80.5% in the MW ablation. There was no significant difference in the 1-, 3-, and 5-year overall survival rates (P = 0.780 and the 1-, 3-, and 5-year disease-free survival rates (P = 0.123 between RF and MW ablation. At subgroup analyses, for patients with tumors ≤ 3.0 cm, there was no significant difference in the 1-, 3-, and 5-year overall survival rates (P = 0.067 and the corresponding disease-free survival rates(P = 0.849. For patients with tumor diameters of 3.1-5.0 cm, the 1-, 3-, and 5-year overall survival rates were 87.1%, 61.3%, and 40.1% for RF ablation and 85.4%, 36.6%, and 22% for MW ablation, with no significant difference (P = 0.068. The corresponding disease-free survival rates were 74.2%, 54.8%, and 45.2% for the RF ablation group and 53.3%, 26.8%, and 17.1% for the MW ablation group. The disease-free survival curve for the RF ablation group was significantly better than that for the MW ablation group (P = 0.018. RF ablation and MW ablation are both effective methods in treating hepatocellular carcinomas, with no significant differences in CA, LTP, DR, and overall survival.

Intracardiac echo-facilitated 3D electroanatomical mapping of ventricular arrhythmias from the papillary muscles: assessing the 'fourth dimension' during ablation.

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Proietti, Riccardo; Rivera, Santiago; Dussault, Charles; Essebag, Vidal; Bernier, Martin L; Ayala-Paredes, Felix; Badra-Verdu, Mariano; Roux, Jean-François

2017-01-01

Ventricular arrhythmias (VA) originating from a papillary muscle (PM) have recently been described as a distinct clinical entity with peculiar features that make its treatment with catheter ablation challenging. Here, we report our experience using an intracardiac echo-facilitated 3D electroanatomical mapping approach in a case series of patients undergoing ablation for PM VA. Sixteen patients who underwent catheter ablation for ventricular tachycardia (VT) or symptomatic premature ventricular contractions originating from left ventricular PMs were included in the study. A total of 24 procedures (mean 1.5 per patient) were performed: 15 using a retrograde aortic approach and 9 using a transseptal approach. Integrated intracardiac ultrasound for 3D electroanatomical mapping was used in 15 of the 24 procedures. The posteromedial PM was the most frequent culprit for the clinical arrhythmia, and the body was the part of the PM most likely to be the successful site for ablation. The site of ablation was identified based on the best pace map matching the clinical arrhythmia and the site of earliest the activation. At a mean follow-up of 10.5 ± 7 months, only two patients had recurrent arrhythmias following a repeat ablation procedure. An echo-facilitated 3D electroanatomical mapping allows for real-time creation of precise geometries of cardiac chambers and endocavitary structures. This is useful during procedures such as catheter ablation of VAs originating from PMs, which require detailed representation of anatomical landmarks. Routine adoption of this technique should be considered to improve outcomes of PM VA ablation. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.

Plasma-mediated radiofrequency ablation followed by percutaneous cementoplasty under fluoro-CT guidance: a case report.

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Carrafiello, Gianpaolo; Laganà, Domenico; Ianniello, Andrea; Fontana, Federico; Mangini, Monica; Mocciardini, Lucia; Spanò, Emanuela; Piacentino, Filippo; Cuffari, Salvatore; Fugazzola, Carlo

2009-08-17

We report a case of a 81-year-old Caucasian man with colorectal carcinoma, treated by surgery in 1998, referred for palliative treatment of a refractory painful caused by osteolytic metastases of 2.5 cm in back-upper ilium spine. Plasma-mediated radiofrequency ablation was performed under conscious sedation, using Fluoroscopic Computer Tomography guidance. After completing the ablation phase of the procedure, a mixture of bone cement and Biotrace sterile barium sulfate was injected into the ablated cavity.Patient was evaluated by using the Brief Pain Inventory and considering pain interference with daily living at day 1 and 3 and week 1, 2, 3, 4 by means of a telephone interview. A post-procedure Computer Tomography scan was performed to examine the distribution of cement deposition few minutes after the procedure. The plasma mediated RFA and cementoplasty were well tolerated by the patient who did not develop any complication.

Mitral valve perforation appearing years after radiofrequency ablation

DEFF Research Database (Denmark)

Fisch-Thomsen, Marie; Jensen, Jesper K; Egeblad, Henrik

2011-01-01

The case is reported of a young adult with Wolff-Parkinson-White (WPW) syndrome who, three years after a complicated radiofrequency (RF) catheter ablation procedure, developed dyspnea on exertion. Echocardiography revealed severe mitral valve regurgitation caused by a perforation of the posterior...

Palliative Treatment of Rectal Carcinoma Recurrence Using Radiofrequency Ablation

International Nuclear Information System (INIS)

Mylona, Sophia; Karagiannis, Georgios; Patsoura, Sofia; Galani, Panagiota; Pomoni, Maria; Thanos, Loukas

2012-01-01

Purpose: To evaluate the safety and efficacy of CT-guided radiofrequency (RF) ablation for the palliative treatment of recurrent unresectable rectal tumors. Materials and Methods: Twenty-seven patients with locally recurrent rectal cancer were treated with computed tomography (CT)-guided RF ablation. Therapy was performed with the patient under conscious sedation with a seven- or a nine-array expandable RF electrode for 8–10 min at 80–110°C and a power of 90–110 W. All patients went home under instructions the next day of the procedure. Brief Pain Inventory score was calculated before and after (1 day, 1 week, 1 month, 3 months, and 6 months) treatment. Results: Complete tumor necrosis rate was 77.8% (21 of a total 27 procedures) despite lesion location. BPI score was dramatically decreased after the procedure. The mean preprocedure BPI score was 6.59, which decreased to 3.15, 1.15, and 0.11 at postprocedure day 1, week 1, and month 1, respectively, after the procedure. This decrease was significant (p < 0.01 for the first day and p < 0.001 for the rest of the follow-up intervals (paired Student t test; n − 1 = 26) for all periods during follow-up. Six patients had partial tumor necrosis, and we were attempted to them with a second procedure. Although the necrosis area showed a radiographic increase, no complete necrosis was achieved (secondary success rate 65.6%). No immediate or delayed complications were observed. Conclusion: CT-guided RF ablation is a minimally invasive, safe, and highly effective technique for treatment of malignant rectal recurrence. The method is well tolerated by patients, and pain relief is quickly achieved.

Laparoscopic Ultrasound-Guided Radiofrequency Ablation of Uterine Fibroids

International Nuclear Information System (INIS)

Milic, Andrea; Asch, Murray R.; Hawrylyshyn, Peter A.; Allen, Lisa M.; Colgan, Terence J.; Kachura, John R.; Hayeems, Eran B.

2006-01-01

Four patients with symptomatic uterine fibroids measuring less than 6 cm underwent laparoscopic ultrasound-guided radiofrequency ablation (RFA) using multiprobe-array electrodes. Follow-up of the treated fibroids was performed with gadolinium-enhanced magnetic resonance imaging (MRI) and patients' symptoms were assessed by telephone interviews. The procedure was initially technically successful in 3 of the 4 patients and MRI studies at 1 month demonstrated complete fibroid ablation. Symptom improvement, including a decrease in menstrual bleeding and pain, was achieved in 2 patients at 3 months. At 7 months, 1 of these 2 patients experienced symptom worsening which correlated with recurrent fibroid on MRI. The third, initially technically successfully treated patient did not experience any symptom relief after the procedure and was ultimately diagnosed with adenomyosis. Our preliminary results suggest that RFA is a technically feasible treatment for symptomatic uterine fibroids in appropriately selected patients

Ischemic stroke associated with radio frequency ablation for nodal reentry

International Nuclear Information System (INIS)

Diaz M, Juan C; Duran R, Carlos E; Perafan B, Pablo; Pava M, Luis F

2010-01-01

Atrioventricular nodal reentry tachycardia is the most common type of paroxysmal supraventricular tachycardia. In those patients in whom drug therapy is not effective or not desired, radio frequency ablation is an excellent therapeutic method. Although overall these procedures are fast and safe, several complications among which ischemic stroke stands out, have been reported. We present the case of a 41 year old female patient with repetitive episodes of tachycardia due to nodal reentry who was treated with radiofrequency ablation. Immediately after the procedure she presented focal neurologic deficit consistent with ischemic stroke in the right medial cerebral artery territory. Angiography with angioplastia and abxicimab was performed and then tissue plasminogen activator (rtPA) was locally infused, with appropriate clinical and angiographic outcome.

Global Endometrial Ablation in the Presence of Essure® Microinserts

Science.gov (United States)

Aldape, Diana; Chudnoff, Scott G; Levie, Mark D

2013-01-01

Abnormal uterine bleeding (AUB) affects 30% of women at some time during their reproductive years and is one of the most common reasons a woman sees a gynecologist. Many women are turning to endometrial ablation to manage their AUB. This article reviews the data relating to the available endometrial ablation techniques performed with hysteroscopic sterilization, and focuses on data from patients who had Essure® (Conceptus, San Carlos, CA) coils placed prior to performance of endometrial ablation. Reviewed specifically are data regarding safety and efficacy of these two procedures when combined. Data submitted to the US Food and Drug Administration for the three devices currently approved are reviewed, as well as all published case series. Articles included were selected based on a PubMed search for endometrial ablation (also using the brand names of the different techniques currently available), hysteroscopic sterilization, and Essure. PMID:24358407

Pathological effects of lung radiofrequency ablation that contribute to pneumothorax, using a porcine model.

Science.gov (United States)

Izaaryene, Jean; Cohen, Frederic; Souteyrand, Philippe; Rolland, Pierre-Henri; Vidal, Vincent; Bartoli, Jean-Michel; Secq, Veronique; Gaubert, Jean-Yves

2017-11-01

The incidence of pneumothorax is 7 times higher after lung radiofrequency ablation (RFA) than after lung biopsy. The reasons for such a difference have never been objectified. The histopathologic changes in lung tissue are well-studied and established for RF in the ablation zone. However, it has not been previously described what the nature of thermal injury might be along the shaft of the RF electrode as it traverses through normal lung tissue to reach the ablation zone. The purpose of this study was to determine the changes occurring around the RF needle along the pathway between the ablated zone and the pleura. In 3 anaesthetised and ventilated swine, 6 RFA procedures (right and left lungs) were performed using a 14-gauge unipolar multi-tined retractable 3 cm radiofrequency LeVeen probe with a coaxial introducer positioned under CT fluoroscopic guidance. In compliance with literature guidelines, we implemented a gradually increasing thermo-ablation protocol using a RF generator. Helical CT images were acquired pre- and post-RFA procedure to detect and evaluate pneumothorax. Four percutaneous 19-gauge lung biopsies were also performed on the fourth swine under CT guidance. Swine were sacrificed for lung ex vivo examinations, scanning electron microscopy (SEM) and pathological analysis. Three severe (over 50 ml) pneumothorax were detected after RFA. In each one of them, pathological examination revealed a fistulous tract between ablation zone and pleura. No fistulous tract was observed after biopsies. In the 3 cases of severe pneumothorax, the tract was wide open and clearly visible on post procedure CT images and SEM examinations. The RFA tract differed from the needle biopsy tract. The histological changes that are usually found in the ablated zone were observed in the RFA tract's wall and were related to thermal lesions. These modifications caused the creation of a coagulated pulmonary parenchyma rim between the thermo-ablation zone and the pleural space

Phobos: A novel software for recording rodents' behavior during the thigmotaxis and the elevated plus-maze test.

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Telonis, Aristeidis G; Margarity, Marigoula

2015-07-10

Evaluation of fear and anxiety levels offers valuable insight on the impact of experimental conditions. The elevated plus-maze and the open field (thigmotactic responce) tests are two well-established behavioral procedures for the quantification of anxiety in rodents. In this study, Phobos, a novel, effective and simple application developed for recording rodents' behavior during the elevated plus-maze and the open-field test, is being presented. Phobos is able to generate all basic locomotor-related behavioral results at once, immediately after a simple manual record of the rodent's position, along with simultaneous analysis of the experiment in 5-min periods. The efficiency of Phobos is demonstrated by presenting results from the two behavioral tests showing that animal's behavior unfolds differently in each one. Phobos manages to ease the experimenter from laborious work by providing self-explanatory characteristics and a convenient way to record the behavior of the animal, while it quickly calculates all basic locomotor-related parameters, easing behavioral studies. Phobos is freely accessible at https://sourceforge.net/projects/phobosapplication/. Copyright © 2015. Published by Elsevier Ireland Ltd.

A novel technique to optimise the length of a linear accelerator treatment room maze without compromising radiation protection.

Science.gov (United States)

Al-Affan, I A M; Evans, S C; Qutub, M; Hugtenburg, R P

2018-03-01

Simulations with the FLUktuierende KAskade (FLUKA) Monte Carlo code were used to establish the possibility of introducing lead to cover the existing concrete walls of a linear accelerator treatment room maze, in order to reduce the dose of the scattered photons at the maze entrance. In the present work, a pilot study performed at Singleton Hospital in Swansea was used to pioneer the use of lead sheets of various thicknesses to absorb scattered low energy photons in the maze. The dose reduction was considered to be due to the strong effect of the photoelectric interaction in lead resulting in attenuation of the back-scattered photons. Calculations using FLUKA with mono-energetic photons were used to represent the main components of the x-ray spectrum up to 10 MV. Mono-energetic photons were used to enable the study of the behaviour of each energy component from the associated interaction processes. The results showed that adding lead of 1 to 4 mm thickness to the walls and floor of the maze reduced the dose at the maze entrance by up to 80%. Subsequent scatter dose measurements performed at the maze entrance of an existing treatment room with lead sheet of 1.3 mm thickness added to the maze walls and floor supported the results from the simulations. The dose reduction at the maze entrance with the lead in place was up to 50%. The variation between simulation and measurement was attributed to the fact that insufficient lead was available to completely cover the maze walls and floor. This novel proposal of partly, or entirely, covering the maze walls with lead a few millimetres in thickness has implications for the design of linear accelerator treatment rooms since it has the potential to provide savings, in terms of space and costs, when an existing maze requires upgrading in an environment where space is limited and the maze length cannot be extended sufficiently to reduce the dose.

Place and Response Learning in the Open-field Tower Maze.

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Lipatova, Olga; Campolattaro, Matthew M; Toufexis, Donna J; Mabry, Erin A

2015-10-28

This protocol describes how the Open-field Tower Maze (OFTM) paradigm is used to study spatial learning in rodents. This maze is especially useful for examining how rats learn to use a place- or response-learning to successfully navigate in an open-field arena. Additionally, this protocol describes how the OFTM differs from other behavioral maze paradigms that are commonly used to study spatial learning in rodents. The OFTM described in this article was adapted from the one previously described by Cole, Clipperton, and Walt (2007). Specifically, the OFTM was created to test spatial learning in rodents without the experimenter having to consider how "stress" might play a role as a confounding variable. Experiments have shown that stress-alone can significantly affect cognitive function(1). The representative results section contains data from an experiment that used the OFTM to examine the effects of estradiol treatment on place- and response-learning in adult female Sprague Dawley rats(2). Future studies will be designed to examine the role of the hippocampus and striatum in place- and response-learning in the OFTM.

Percutaneous ultrasound-guided radiofrequency ablation for kidney tumors in patients with surgical risk

International Nuclear Information System (INIS)

Salagierski, Marek; Salagierski, Maciej; Sosnowski, Marek; Salagierska-Barwinska, Anna

2006-01-01

The aim of this study was to describe our experience with percutaneous ultrasound-guided radiofrequency ablation of kidney tumors. From July 2002 to August 2005, 45 radiofrequency ablations (RFA) in 42 selected patients with kidney tumor were performed. The patients had either contraindications to surgery procedures or had a solitary kidney. The average tumor size was 37.5 mm (range, 18-59 mm) with the mean age of 68 years (range, 28-83 years). RFA were performed based on radiographic findings. Needle biopsy was made only twice. Monopolar Cool-tip Tyco or bipolar Celon Olympus radiofrequency devices were used. The procedure was performed under conscious sedation with local anesthesia. Treatment efficacy was assessed by computed tomography and by Doppler ultrasound. The absence of contrast enhancement on computed tomography was considered to be a successful treatment. The average follow up was 14 months (range, 3-36 months). In 42 tumors (93%), total absence of contrast enhancement was obtained after the initial RFA and in three tumors (7%) after the second ablation session. There were no complications following 41 procedures, including all ablations in small (<35 mm) renal masses. In four procedures, minor complications were observed. All patients are alive. There has been no need for chronic hemodialysis and, until now, we have not observed any local recurrences with the exception of one metastasis to an ipsilateral adrenal gland. RFA of kidney tumors is a promising alternative treatment which could be considered for patients who are not suitable for surgery. (author)

Case Experience of Radiofrequency Ablation for Benign Thyroid Nodules: From an Ex Vivo Animal Study to an Initial Ablation in Taiwan

Directory of Open Access Journals (Sweden)

Ming-Tsang Lee

2016-03-01

Full Text Available Radiofrequency ablation (RFA is a minimally invasive technique, used with ultrasound or computed tomography guidance, which can produce tissue coagulation necrosis in various kinds of tumors in the human body. In the past 10 years, numerous studies about RFA in benign thyroid nodules have been published. Reviewing these studies, we noticed that the effectiveness of ablation was higher when it was performed with the “moving-shot technique” via an internally cooled electrode. A consensus statement published from the Korean Society of Radiology also suggested the moving-shot technique as a standard ablation procedure for benign thyroid nodule ablation in Korea. In Taiwan, most symptomatic benign nodules are currently treated with surgical removal. RFA for mass lesions is primarily performed for the treatment of metastatic hepatic tumors. In our case, we have attempted to introduce RFA for benign thyroid nodules in Taiwan. Because endocrinologists in Taiwan were not familiar with this technique, we adopted a stepwise approach in learning how to perform RFA. We conducted ex vivo animal ablation exercises to gain experience in setting the radiofrequency generator for the right ablation mode and appropriate power output. The thyroid nodule volume reduction rate after 1 year of follow up was approximately 50% in this case. The most important thing we learned from this trial is that we confirmed the safety of thyroid nodule ablation. To the best of our knowledge, this is the first reported study of RFA of a thyroid nodule in Taiwan.

Histopathology of cryoballoon ablation-induced phrenic nerve injury.

Science.gov (United States)

Andrade, Jason G; Dubuc, Marc; Ferreira, Jose; Guerra, Peter G; Landry, Evelyn; Coulombe, Nicolas; Rivard, Lena; Macle, Laurent; Thibault, Bernard; Talajic, Mario; Roy, Denis; Khairy, Paul

2014-02-01

Hemi-diaphragmatic paralysis is the most common complication associated with cryoballoon ablation for atrial fibrillation, yet the histopathology of phrenic nerve injury has not been well described. A preclinical randomized study was conducted to characterize the histopathology of phrenic nerve injury induced by cryoballoon ablation and assess the potential for electromyographic (EMG) monitoring to limit phrenic nerve damage. Thirty-two dogs underwent cryoballoon ablation of the right superior pulmonary vein with the objective of inducing phrenic nerve injury. Animals were randomized 1:1 to standard monitoring (i.e., interruption of ablation upon reduction in diaphragmatic motion) versus EMG guidance (i.e., cessation of ablation upon a 30% reduction in the diaphragmatic compound motor action potential [CMAP] amplitude). The acute procedural endpoint was achieved in all dogs. Phrenic nerve injury was characterized by Wallerian degeneration, with subperineural injury to large myelinated axons and evidence of axonal regeneration. The degree of phrenic nerve injury paralleled the reduction in CMAP amplitude (P = 0.007). Animals randomized to EMG guidance had a lower incidence of acute hemi-diaphragmatic paralysis (50% vs 100%; P = 0.001), persistent paralysis at 30 days (21% vs 75%; multivariate odds ratio 0.12, 95% confidence interval [0.02, 0.69], P = 0.017), and a lesser severity of histologic injury (P = 0.001). Mature pulmonary vein ablation lesion characteristics, including circumferentiality and transmurality, were similar in both groups. Phrenic nerve injury induced by cryoballoon ablation is axonal in nature and characterized by Wallerian degeneration, with potential for recovery. An EMG-guided approach is superior to standard monitoring in limiting phrenic nerve damage. © 2013 Wiley Periodicals, Inc.

Multipolar hepatic radiofrequency ablation using up to six applicators: preliminary results

International Nuclear Information System (INIS)

Bruners, P.; Schmitz-Rode, T.; Guenther, R.W.; Mahnken, A.

2008-01-01

Purpose: to evaluate the clinical feasibility and safety of hepatic radiofrequency (RF) ablation using a multipolar RF system permitting the simultaneous use of up to six electrodes. Materials and methods: ten patients (3 female, 7 male, mean age 61) suffering from 29 hepatic metastases (range: 1-5) of different tumors were treated with a modified multipolar RF system (CelonLab Power, Celon Medical Instruments, Teltow, Germany) operating four to six needle-shaped internally cooled RF applicators. The procedure duration, applied energy and generator output were recorded during the intervention. The treatment result and procedure-related complications were analyzed. The achieved coagulation volume was calculated on the basis of contrast-enhanced CT scans 24 hours after RF ablation. Results: complete tumor ablation was achieved in all cases as determined by the post-interventional lack of contrast enhancement in the target region using four applicators in five patients, five applicators in one patient and six applicators in four patients. A mean energy deposition of 353.9 ± 176.2 kJ resulted in a mean coagulation volume of 115.9 ± 79.5 cm 3 . The mean procedure duration was 74.9 ± 21.2 minutes. Four patients showed an intraabdominal hemorrhage which necessitated further interventional treatment (embolization; percutaneous histoacryl injection) in two patients. (orig.)

Right atrium positioning for exposure of right pulmonary veins during off-pump atrial fibrillation ablation.

Science.gov (United States)

Suwalski, Grzegorz; Emery, Robert; Mróz, Jakub; Kaczejko, Kamil; Gryszko, Leszek; Cwetsch, Andrzej; Skrobowski, Andrzej

2017-06-01

Concomitant surgical ablation of atrial fibrillation (AF) is recommended for patients undergoing off-pump coronary revascularization in the presence of this arrhythmia. Achievement of optimal visualization of pulmonary veins while maintaining stable haemodynamic conditions is crucial for proper completion of the ablation procedure. This study evaluates the safety and feasibility of right atrial positioning using a suction-based cardiac positioner as opposed to compressive manoeuvres for exposure during off-pump surgical ablation for AF. Thirty-four consecutive patients underwent pulmonary vein isolation, ganglionated plexi ablation and left atrial appendage occlusion during off-pump coronary artery bypass grafting. Right atrial suction positioning was used to visualize right pulmonary veins. Safety and feasibility end points were analysed intraoperatively and in the early postoperative course. In all patients, right atrial positioning created optimal conditions to complete transverse and oblique sinus blunt dissection, correct placement of a bipolar ablation probe, detection and ablation of ganglionated plexi and conduction block assessment. In all patients, this entire right-sided ablation procedure was completed with a single exposure manoeuvre. Feasibility end points were achieved in all study patients. This report documents the safety and feasibility of right atrial exposure using a suction-based cardiac positioner to complete ablation for AF concomitant with off-pump coronary revascularization. This technique may be widely adopted to create stable haemodynamic conditions and optimal visualization of the right pulmonary veins. © The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Inadvertent puncture of the aortic noncoronary cusp during postoperative left atrial tachycardia ablation

Directory of Open Access Journals (Sweden)

Dursun Aras, MD

2015-08-01

Full Text Available Transseptal catheterization has become part of the interventional electrophysiologist׳s technical armamentarium since the development of left atrial catheter ablation and percutaneous technologies for treating mitral and aortic valve disease. Although frequently performed, the procedure׳s most feared complication is aortic root penetration. Focal atrial tachycardia has been described as the most common late sequela of surgical valve replacements. We present a complicated case involving the inadvertent delivery of an 8 French sheath across the noncoronary cusp during radiofrequency catheter ablation for left atrial tachycardia originating from the mitral annulus in a patient with prior mitral valve replacement.

Complications associated with radiofrequency ablation of pulmonary veins.

Science.gov (United States)

Madrid Pérez, J M; García Barquín, P M; Villanueva Marcos, A J; García Bolao, J I; Bastarrika Alemañ, G

Radiofrequency ablation is an efficacious alternative in patients with symptomatic atrial fibrillation who do not respond to or are intolerant to at least one class I or class III antiarrhythmic drug. Although radiofrequency ablation is a safe procedure, complications can occur. Depending on the location, these complications can be classified into those that affect the pulmonary veins themselves, cardiac complications, extracardiac intrathoracic complications, remote complications, and those that result from vascular access. The most common complications are hematomas, arteriovenous fistulas, and pseudoaneurysms at the puncture site. Some complications are benign and transient, such as gastroparesis or diaphragmatic elevation, whereas others are potentially fatal, such as cardiac tamponade. Radiologists must be familiar with the complications that can occur secondary to pulmonary vein ablation to ensure early diagnosis and treatment. Copyright © 2016 SERAM. Publicado por Elsevier España, S.L.U. All rights reserved.

Robotic-assisted thermal ablation of liver tumours

International Nuclear Information System (INIS)

Abdullah, Basri Johan Jeet; Yeong, Chai Hong; Goh, Khean Lee; Yoong, Boon Koon; Ho, Gwo Fuang; Yim, Carolyn Chue Wai; Kulkarni, Anjali

2015-01-01

This study aimed to assess the technical success, radiation dose, safety and performance level of liver thermal ablation using a computed tomography (CT)-guided robotic positioning system. Radiofrequency and microwave ablation of liver tumours were performed on 20 patients (40 lesions) with the assistance of a CT-guided robotic positioning system. The accuracy of probe placement, number of readjustments and total radiation dose to each patient were recorded. The performance level was evaluated on a five-point scale (5-1: excellent-poor). The radiation doses were compared against 30 patients with 48 lesions (control) treated without robotic assistance. Thermal ablation was successfully completed in 20 patients with 40 lesions and confirmed on multiphasic contrast-enhanced CT. No procedure related complications were noted in this study. The average number of needle readjustment was 0.8 ± 0.8. The total CT dose (DLP) for the entire robotic assisted thermal ablation was 1382 ± 536 mGy.cm, while the CT fluoroscopic dose (DLP) per lesion was 352 ± 228 mGy.cm. There was no statistically significant (p > 0.05) dose reduction found between the robotic-assisted versus the conventional method. This study revealed that robotic-assisted planning and needle placement appears to be safe, with high accuracy and a comparable radiation dose to patients. (orig.)

Robotic-assisted thermal ablation of liver tumours

Energy Technology Data Exchange (ETDEWEB)

Abdullah, Basri Johan Jeet; Yeong, Chai Hong [University of Malaya, Department of Biomedical Imaging and University of Malaya Research Imaging Centre, Faculty of Medicine, Kuala Lumpur (Malaysia); University of Malaya, Department of Internal Medicine, Faculty of Medicine, Kuala Lumpur (Malaysia); Goh, Khean Lee [University of Malaya, Department of Internal Medicine, Faculty of Medicine, Kuala Lumpur (Malaysia); Yoong, Boon Koon [University of Malaya, Department of Surgery, Faculty of Medicine, Kuala Lumpur (Malaysia); Ho, Gwo Fuang [University of Malaya, Department of Oncology, Faculty of Medicine, Kuala Lumpur (Malaysia); Yim, Carolyn Chue Wai [University of Malaya, Department of Anesthesia, Faculty of Medicine, Kuala Lumpur (Malaysia); Kulkarni, Anjali [Perfint Healthcare Corporation, Florence, OR (United States)

2015-01-15

This study aimed to assess the technical success, radiation dose, safety and performance level of liver thermal ablation using a computed tomography (CT)-guided robotic positioning system. Radiofrequency and microwave ablation of liver tumours were performed on 20 patients (40 lesions) with the assistance of a CT-guided robotic positioning system. The accuracy of probe placement, number of readjustments and total radiation dose to each patient were recorded. The performance level was evaluated on a five-point scale (5-1: excellent-poor). The radiation doses were compared against 30 patients with 48 lesions (control) treated without robotic assistance. Thermal ablation was successfully completed in 20 patients with 40 lesions and confirmed on multiphasic contrast-enhanced CT. No procedure related complications were noted in this study. The average number of needle readjustment was 0.8 ± 0.8. The total CT dose (DLP) for the entire robotic assisted thermal ablation was 1382 ± 536 mGy.cm, while the CT fluoroscopic dose (DLP) per lesion was 352 ± 228 mGy.cm. There was no statistically significant (p > 0.05) dose reduction found between the robotic-assisted versus the conventional method. This study revealed that robotic-assisted planning and needle placement appears to be safe, with high accuracy and a comparable radiation dose to patients. (orig.)

[Ablation on the undersurface of a LASIK flap. Instrument and method for continuous eye tracking].

Science.gov (United States)

Taneri, S; Azar, D T

2007-02-01

The risk of iatrogenic keratectasia after laser in situ keratomileusis (LASIK) increases with thinner posterior stromal beds. Ablations on the undersurface of a LASIK flap could only be performed without the guidance of an eye tracker, which may lead to decentration. A new method for laser ablation with flying spot lasers on the undersurface of a LASIK flap was developed that enables the use of an active eye tracker by utilizing a novel instrument. The first clinical results are reported. Patients wishing an enhancement procedure were eligible for a modified repeat LASIK procedure if the flaps cut in the initial procedure were thick enough to perform the intended additional ablation on the undersurface leaving at least 90 microm of flap thickness behind. (1) The horizontal axis and the center of the entrance pupil were marked on the epithelial side of the flap using gentian violet dye. (2) The flap was reflected on a newly designed flap holder which had a donut-shaped black marking. (3) The eye tracker was centered on the mark visible in transparency on the flap. (4) Ablation with a flying spot Bausch & Lomb Technolas 217z laser was performed on the undersurface of the flap with a superior hinge taking into account that in astigmatic ablations the cylinder axis had to be mirrored according to the formula: axis on the undersurface=180 degrees -axis on the stromal bed. (5) The flap was repositioned. Detection of the marking on the modified flap holder and continuous tracking instead of the real pupil was possible in all of the 12 eyes treated with this technique. It may be necessary to cover the real pupil during ablation in order not to confuse the eye tracker. Ablation could be performed without decentration or loss of best spectacle-corrected visual acuity. Refractive results in minor corrections were good without nomogram adjustment. Using this novel flap holder with a marking that is tracked instead of the real pupil, centered ablations with a flying spot laser

Transarterial ablation of hepatocellular carcinoma. Status and developments

International Nuclear Information System (INIS)

Radeleff, B.A.; Stampfl, U.; Sommer, C.M.; Bellemann, N.; Kauczor, H.U.; Hoffmann, K.; Ganten, T.; Ehehalt, R.

2012-01-01

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide and represents the main cause of death among European patients with liver cirrhosis. Only 30-40% of patients diagnosed with HCC are candidates for curative treatment options (e.g. surgical resection, liver transplantation or ablation). The remaining majority of patients must undergo local regional and palliative therapies. Transvascular ablation of HCC takes advantage of the fact that the hypervascularized HCC receives most of its blood supply from the hepatic artery. In this context transvascular ablation describes different therapy regimens which can be assigned to four groups: cTACE (conventional transarterial chemoembolization), bland embolization (transarterial embolization TAE), DEB-TACE (TACE with drug-eluting beads, DEB) and SIRT (selective internal radiation therapy, radioembolization). Conventional TACE is the most common type of transvascular ablation and represents a combination of intra-arterial chemotherapy and embolization with occlusion of the arterial blood supply. However, there is no standardized regimen with respect to the chemotherapeutic drug, the embolic agent, the usage of lipiodol and the interval between the TACE procedures. Even the exact course of a cTACE procedure (order of chemotherapy or embolization) is not standardized. It remains unclear whether or not intra-arterial chemotherapy is definitely required as bland embolization using very small, tightly calibrated spherical particles (without intra-arterial administration of a chemotherapeutic drug) shows tumor necrosis comparable to cTACE. For DEB-TACE microparticles loaded with a chemotherapeutic drug combine the advantages of cTACE and bland embolization. Thereby, a continuing chemotherapeutic effect within the tumor might cause a further increase in intratumoral cytotoxicity and at the same time a decrease in systemic toxicity. (orig.) [de

Use of an Eight-arm Radial Water Maze to Assess Working and Reference Memory Following Neonatal Brain Injury

OpenAIRE

Penley, Stephanie C.; Gaudet, Cynthia M.; Threlkeld, Steven W.

2013-01-01

Working and reference memory are commonly assessed using the land based radial arm maze. However, this paradigm requires pretraining, food deprivation, and may introduce scent cue confounds. The eight-arm radial water maze is designed to evaluate reference and working memory performance simultaneously by requiring subjects to use extra-maze cues to locate escape platforms and remedies the limitations observed in land based radial arm maze designs. Specifically, subjects are required to avoid ...

Acute and early outcomes of focal impulse and rotor modulation (FIRM)-guided rotors-only ablation in patients with nonparoxysmal atrial fibrillation.

Science.gov (United States)

Gianni, Carola; Mohanty, Sanghamitra; Di Biase, Luigi; Metz, Tamara; Trivedi, Chintan; Gökoğlan, Yalçın; Güneş, Mahmut F; Bai, Rong; Al-Ahmad, Amin; Burkhardt, J David; Gallinghouse, G Joseph; Horton, Rodney P; Hranitzky, Patrick M; Sanchez, Javier E; Halbfaß, Phillipp; Müller, Patrick; Schade, Anja; Deneke, Thomas; Tomassoni, Gery F; Natale, Andrea

2016-04-01

Focal impulse and rotor modulation (FIRM)-guided ablation targets sites that are thought to sustain atrial fibrillation (AF). The purpose of this study was to evaluate the acute and mid-term outcomes of FIRM-guided only ablation in patients with nonparoxysmal AF. We prospectively enrolled patients with persistent and long-standing persistent (LSP) AF at three centers to undergo FIRM-guided only ablation. We evaluated acute procedural success (defined as AF termination, organization, or ≥10% slowing), safety (incidence of periprocedural complications), and long-term success (single-procedure freedom from atrial tachycardia [AT]/AF off antiarrhythmic drugs [AAD] after a 2-month blanking period). Twenty-nine patients with persistent (N = 20) and LSP (N = 9) AF underwent FIRM mapping. Rotors were presents in all patients, with a mean of 4 ± 1.2 per patient (62% were left atrial); 1 focal impulse was identified. All sources were successfully ablated, and overall acute success rate was 41% (0 AF termination, 2 AF slowing, 10 AF organization). There were no major procedure-related adverse events. After a mean 5.7 months of follow-up, single-procedure freedom from AT/AF without AADs was 17%. In nonparoxysmal AF patients, targeted ablation of FIRM-identified rotors is not effective in obtaining AF termination, organization, or slowing during the procedure. After mid-term follow-up, the strategy of ablating FIRM-identified rotors alone did not prevent recurrence from AT/AF. Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

CBM maze-scores as indicators of reading level and growth for seventh-grade students

NARCIS (Netherlands)

Chung, S.; Espin, C.A.; Stevenson, C.E.

The technical adequacy of CBM maze-scores as indicators of reading level and growth for seventh-grade secondary-school students was examined. Participants were 452 Dutch students who completed weekly maze measures over a period of 23 weeks. Criterion measures were school level, dyslexia status,

Microwave Ablation: Comparison of Simultaneous and Sequential Activation of Multiple Antennas in Liver Model Systems.

Science.gov (United States)

Harari, Colin M; Magagna, Michelle; Bedoya, Mariajose; Lee, Fred T; Lubner, Meghan G; Hinshaw, J Louis; Ziemlewicz, Timothy; Brace, Christopher L

2016-01-01

To compare microwave ablation zones created by using sequential or simultaneous power delivery in ex vivo and in vivo liver tissue. All procedures were approved by the institutional animal care and use committee. Microwave ablations were performed in both ex vivo and in vivo liver models with a 2.45-GHz system capable of powering up to three antennas simultaneously. Two- and three-antenna arrays were evaluated in each model. Sequential and simultaneous ablations were created by delivering power (50 W ex vivo, 65 W in vivo) for 5 minutes per antenna (10 and 15 minutes total ablation time for sequential ablations, 5 minutes for simultaneous ablations). Thirty-two ablations were performed in ex vivo bovine livers (eight per group) and 28 in the livers of eight swine in vivo (seven per group). Ablation zone size and circularity metrics were determined from ablations excised postmortem. Mixed effects modeling was used to evaluate the influence of power delivery, number of antennas, and tissue type. On average, ablations created by using the simultaneous power delivery technique were larger than those with the sequential technique (P Simultaneous ablations were also more circular than sequential ablations (P = .0001). Larger and more circular ablations were achieved with three antennas compared with two antennas (P simultaneous power delivery creates larger, more confluent ablations with greater temperatures than those created with sequential power delivery. © RSNA, 2015.

Critical phase transitions during ablation of atrial fibrillation

Science.gov (United States)

Iravanian, Shahriar; Langberg, Jonathan J.

2017-09-01

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia with significant morbidity and mortality. Pharmacological agents are not very effective in the management of AF. Therefore, ablation procedures have become the mainstay of AF management. The irregular and seemingly chaotic atrial activity in AF is caused by one or more meandering spiral waves. Previously, we have shown the presence of sudden rhythm organization during ablation of persistent AF. We hypothesize that the observed transitions from a disorganized to an organized rhythm is a critical phase transition. Here, we explore this hypothesis by simulating ablation in an anatomically-correct 3D AF model. In 722 out of 2160 simulated ablation, at least one sudden transition from AF to an organized rhythm (flutter) was noted (33%). They were marked by a sudden decrease in the cycle length entropy and increase in the mean cycle length. At the same time, the number of reentrant wavelets decreased from 2.99 ± 0.06 in AF to 1.76 ± 0.05 during flutter, and the correlation length scale increased from 13.3 ± 1.0 mm to 196.5 ± 86.6 mm (both P < 0.0001). These findings are consistent with the hypothesis that transitions from AF to an anatomical flutter behave as phase transitions in complex non-equilibrium dynamical systems with flutter acting as an absorbing state. Clinically, the facilitation of phase transition should be considered a novel mechanism of ablation and may help to design effective ablation strategies.

Comparison of wet radiofrequency ablation with dry radiofrequency ablation and radiofrequency ablation using hypertonic saline preinjection: ex vivo bovine liver

International Nuclear Information System (INIS)

Lee, Jeong Min; Han, Joon Koo; Kim, Se Hyung; Lee, Jae Young; Park, Hee Sun; Hur, Hurn; Choi, Byung Ihn; Shin, Kyung Sook

2004-01-01

We wished to compare the in-vitro efficiency of wet radiofrequency (RF) ablation with the efficiency of dry RF ablation and RF ablation with preinjection of NaCl solutions using excised bovine liver. Radiofrequency was applied to excised bovine livers in a monopolar mode for 10 minutes using a 200 W generator and a perfused-cooled electrode with or without injection or slow infusion of NaCl solutions. After placing the perfused-cooled electrode in the explanted liver, 50 ablation zones were created with five different regimens: group A; standard dry RF ablation, group B; RF ablation with 11 mL of 5% NaCl solution preinjection, group C; RF ablation with infusion of 11 mL of 5% NaCl solution at a rate of 1 mL/min, group D; RFA with 6 mL of 36% NaCl solution preinjection, group E; RF ablation with infusion of 6 mL of 36% NaCl solution at a rate of 0.5 mL/min. In groups C and E, infusion of the NaCl solutions was started 1 min before RF ablation and then maintained during RF ablation (wet RF ablation). During RF ablation, we measured the tissue temperature at 15 mm from the electrode. The dimensions of the ablation zones and changes in impedance, current and liver temperature during RF ablation were then compared between the groups. With injection or infusion of NaCl solutions, the mean initial tissue impedance prior to RF ablation was significantly less in groups B, C, D, and E (43-75 Ω) than for group A (80 Ω) (ρ 3 in group A; 12.4 ± 3.8 cm 3 in group B; 80.9 ± 9.9 cm 3 in group C; 45.3 ± 11.3 cm 3 in group D and 81.6 ± 8.6 cm 3 in group E. The tissue temperature measured at 15 mm from the electrode was higher in groups C, D and E than other groups (ρ < 0.05): 53 ± 12 .deg. C in group A, 42 ± 2 .deg. C in group B, 93 ± 8 .deg. C in group C; 79 ± 12 .deg. C in group D and 83 ± 8 .deg.C in group E. Wet RF ablation with 5% or 36% NaCl solutions shows better efficiency in creating a large ablation zone than does dry RF ablation or RF ablation with

Ablation of tumor and inflammatory tissue with absolute ethanol

Energy Technology Data Exchange (ETDEWEB)

Uflacker, R.; Paolini, R.M.; Nobrega, M.

Absolute ethanol was used to ablate tumors, inflammatory lesions, and end-stage nephrosclerotic kidneys in 38 patients. Thirty patients had various types of renal tumors, and 3 had chronic end-stage renal failure with malignant hypertension. One patient had a fibrosarcoma of the right leg and one had a metastatis in the humerus from a renal carcinoma. A large adrenal carcinoma was treated with absolute ethanol in a patient who had liver metastases that were ablated one year after the first procedure. An additional patient had metastatic liver disease from a non-functioning adrenal carcinoma. The remaining patient had an extensive hypervascular inflammatory lesion (tuberculosis and aspergilloma) of the right upper pulmonary lobe. In addition to ethanol, coils were introduced in one patient and Gelfoam in another. The amount of ethanol used ranged from 5 to 50 ml. Twenty-two patients suffered from considerable transient pain during ethanol injection, but sedation was necessary in only 3 of them. Skin necrosis appeared in 2 patients requiring plastic reconstruction in one of them. Two patients died within 5 days of the procedure unrelated to the ablation. Two patients presented upper gastrointestinal bleeding within 2 days of the ethanol injection and one of these died in acute renal failure. One patient suffered from left colonic infarction after left renal tumor ablation, but survived for several months. Absolute ethanol was a useful and efficient sclerosing agent causing extensive tumor destruction and marked reduction of the vascularity in tumor and inflammatory lesions, but caused an 18% complication rate.

The adenosine A2A antagonist MSX-3 reverses the effects of the dopamine antagonist haloperidol on effort-related decision making in a T-maze cost/benefit procedure.

Science.gov (United States)

Mott, Allison M; Nunes, Eric J; Collins, Lyndsey E; Port, Russell G; Sink, Kelly S; Hockemeyer, Jörg; Müller, Christa E; Salamone, John D

2009-05-01

Mesolimbic dopamine (DA) is a critical component of the brain circuitry regulating behavioral activation and effort-related processes. Research involving choice tasks has shown that rats with impaired DA transmission reallocate their instrumental behavior away from food-reinforced tasks with high response requirements and instead select less effortful food-seeking behaviors. Previous work showed that adenosine A(2A) antagonism can reverse the effects of the DA antagonist haloperidol in an operant task that assesses effort-related choice. The present work used a T-maze choice procedure to assess the effects of adenosine A(2A) and A(1) antagonism. With this task, the two arms of the maze have different reinforcement densities (four vs. two food pellets), and a vertical 44 cm barrier is positioned in the arm with the higher density, presenting the animal with an effort-related challenge. Untreated rats strongly prefer the arm with the high density of food reward and climb the barrier in order to obtain the food. Haloperidol produced a dose-related (0.05-0.15 mg/kg i.p.) reduction in the number of trials in which the rats chose the high-barrier arm. Co-administration of the adenosine A(2A) receptor antagonist MSX-3 (0.75, 1.5, and 3.0 mg/kg i.p.), but not the A(1) antagonist 8-cyclopentyl-1,3-dipropylxanthine (0.75, 1.5, and 3.0 mg/kg i.p.), reversed the effects of haloperidol on effort-related choice and latency. Adenosine A(2A) and D2 receptors interact to regulate effort-related decision making, which may have implications for the treatment of psychiatric symptoms such as psychomotor slowing or anergia that can be observed in depression, parkinsonism, and other disorders.

Interest of Electrostimulation of Peripheral Motor Nerves during Percutaneous Thermal Ablation

International Nuclear Information System (INIS)

Tsoumakidou, Georgia; Garnon, Julien; Ramamurthy, Nitin; Buy, Xavier; Gangi, Afshin

2013-01-01

Purpose: We present our experience of utilizing peripheral nerve electrostimulation as a complementary monitoring technique during percutaneous thermal ablation procedures; and we highlight its utility and feasibility in the prevention of iatrogenic neurologic thermal injury. Methods: Peripheral motor nerve electrostimulation was performed in 12 patients undergoing percutaneous image-guided thermal ablations of spinal/pelvic lesions in close proximity to the spinal cord and nerve roots. Electrostimulation was used in addition to existing insulation (active warming/cooling with hydrodissection, passive insulation with CO 2 insufflation) and temperature monitoring (thermocouples) techniques. Impending neurologic deficit was defined as a visual reduction of muscle response or need for a stronger electric current to evoke muscle contraction, compared with baseline. Results: Significant reduction of the muscle response to electrostimulation was observed in three patients during the ablation, necessitating temporary interruption, followed by injection of warm/cool saline. This resulted in complete recovery of the muscle response in two cases, while for the third patient the response did not improve and the procedure was terminated. No patient experienced postoperative motor deficit. Conclusion: Peripheral motor nerve electrostimulation is a simple, easily accessible technique allowing early detection of impending neurologic injury during percutaneous image-guided thermal ablation. It complements existing monitoring techniques and provides a functional assessment along the whole length of the nerve

Interest of Electrostimulation of Peripheral Motor Nerves during Percutaneous Thermal Ablation

Energy Technology Data Exchange (ETDEWEB)

Tsoumakidou, Georgia, E-mail: gtsoumakidou@yahoo.com; Garnon, Julien, E-mail: juliengarnon@gmail.com; Ramamurthy, Nitin, E-mail: nitin_ramamurthy@hotmail.com; Buy, Xavier, E-mail: xbuy@ymail.com; Gangi, Afshin, E-mail: gangi@unistra.fr [University Hospital of Strasbourg (France)

2013-12-15

Purpose: We present our experience of utilizing peripheral nerve electrostimulation as a complementary monitoring technique during percutaneous thermal ablation procedures; and we highlight its utility and feasibility in the prevention of iatrogenic neurologic thermal injury. Methods: Peripheral motor nerve electrostimulation was performed in 12 patients undergoing percutaneous image-guided thermal ablations of spinal/pelvic lesions in close proximity to the spinal cord and nerve roots. Electrostimulation was used in addition to existing insulation (active warming/cooling with hydrodissection, passive insulation with CO{sub 2} insufflation) and temperature monitoring (thermocouples) techniques. Impending neurologic deficit was defined as a visual reduction of muscle response or need for a stronger electric current to evoke muscle contraction, compared with baseline. Results: Significant reduction of the muscle response to electrostimulation was observed in three patients during the ablation, necessitating temporary interruption, followed by injection of warm/cool saline. This resulted in complete recovery of the muscle response in two cases, while for the third patient the response did not improve and the procedure was terminated. No patient experienced postoperative motor deficit. Conclusion: Peripheral motor nerve electrostimulation is a simple, easily accessible technique allowing early detection of impending neurologic injury during percutaneous image-guided thermal ablation. It complements existing monitoring techniques and provides a functional assessment along the whole length of the nerve.

A randomized prospective long-term (>1 year) clinical trial comparing the efficacy and safety of radiofrequency ablation to 980 nm laser ablation of the great saphenous vein.

Science.gov (United States)

Sydnor, Malcolm; Mavropoulos, John; Slobodnik, Natalia; Wolfe, Luke; Strife, Brian; Komorowski, Daniel

2017-07-01

Purpose To compare the short- and long-term (>1 year) efficacy and safety of radiofrequency ablation (ClosureFAST™) versus endovenous laser ablation (980 nm diode laser) for the treatment of superficial venous insufficiency of the great saphenous vein. Materials and methods Two hundred patients with superficial venous insufficiency of the great saphenous vein were randomized to receive either radiofrequency ablation or endovenous laser ablation (and simultaneous adjunctive therapies for surface varicosities when appropriate). Post-treatment sonographic and clinical assessment was conducted at one week, six weeks, and six months for closure, complications, and patient satisfaction. Clinical assessment of each patient was conducted at one year and then at yearly intervals for patient satisfaction. Results Post-procedure pain ( p radiofrequency ablation group. Improvements in venous clinical severity score were noted through six months in both groups (endovenous laser ablation 6.6 to 1; radiofrequency ablation 6.2 to 1) with no significant difference in venous clinical severity score ( p = 0.4066) or measured adverse effects; 89 endovenous laser ablation and 87 radiofrequency patients were interviewed at least 12 months out with a mean long-term follow-up of 44 and 42 months ( p = 0.1096), respectively. There were four treatment failures in each group, and every case was correctable with further treatment. Overall, there were no significant differences with regard to patient satisfaction between radiofrequency ablation and endovenous laser ablation ( p = 0.3009). There were no cases of deep venous thrombosis in either group at any time during this study. Conclusions Radiofrequency ablation and endovenous laser ablation are highly effective and safe from both anatomic and clinical standpoints over a multi-year period and neither modality achieved superiority over the other.

Treatment of osteoid osteoma using CT-guided radiofrequency ablation versus MR-guided laser ablation: A cost comparison

International Nuclear Information System (INIS)

Maurer, M.H.; Gebauer, B.; Wieners, G.; De Bucourt, M.; Renz, D.M.; Hamm, B.; Streitparth, F.

2012-01-01

Objective: To compare the costs of CT-guided radiofrequency ablation (RFA) and MR-guided laser ablation (LA) for minimally invasive percutaneous treatment of osteoid osteoma. Materials and methods: Between November 2005 and October 2011, 20 patients (14 males, 6 females, mean age 20.3 ± 9.1 years) underwent CT-guided RFA and 24 patients (18 males, 6 females; mean age, 23.8 ± 13.8 years) MR-guided LA (open 1.0 Tesla, Panorama HFO, Philips, Best, Netherlands) for osteoid osteoma diagnosed on the basis of clinical presentation and imaging findings. Prorated costs of equipment use (purchase, depreciation, and maintenance), staff costs, and expenditure for disposables were identified for CT-guided RFA and MR-guided LA procedures. Results: The average total costs per patient were EUR 1762 for CT-guided RFA and EUR 1417 for MR-guided LA. These were (RFA/LA) EUR 92/260 for equipment use, EUR 149/208 for staff, and EUR 870/300 for disposables. Conclusion: MR-guided LA is less expensive than CT-guided RFA for minimally invasive percutaneous ablation of osteoid osteoma. The higher costs of RFA are primarily due to the higher price of the disposable RFA probes.

Inducible forebrain-specific ablation of the transcription factor Creb during adulthood induces anxiety but no spatial/contextual learning deficits

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Miriam Annika Vogt

2014-11-01

Full Text Available The cyclic AMP (cAMP-response element binding protein (CREB is an activity-dependent transcription factor playing a role in synaptic plasticity, learning and memory, and emotional behavior. However, the impact of Creb ablation on rodent behavior is vague as e.g. memory performance of different Creb mutant mice depends on the specific type of mutation per se but additionally on the background and learning protocol differences. Here we present the first targeted ablation of CREB induced during adulthood selectively in principal forebrain neurons in a pure background strain of C57BL/6 mice. All hippocampal principal neurons exhibited lack of CREB expression. Mutant mice showed a severe anxiety phenotype in the openfield and novel object exploration test as well as in the Dark-Light Box Test, but unaltered hippocampus-dependent long-term memory in the Morris water maze and in context dependent fear conditioning. On the molecular level, CREB ablation led to CREM up regulation in the hippocampus and frontal cortex which may at least in part compensate for the loss of CREB. BDNF, a postulated CREB target gene, was down regulated in the frontal lobe but not in the hippocampus; neurogenesis remained unaltered. Our data indicate that in the adult mouse forebrain the late onset of CREB ablation can, in case of memory functionality, be compensated for and is not essential for memory consolidation and retrieval during adulthood. In contrast, the presence of CREB protein during adulthood seems to be pivotal for the regulation of emotional behavior.

Catheter Ablation of Atrial Fibrillation in Patients with Hardware in the Heart - Septal Closure Devices, Mechanical Valves and More.

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Bartoletti, Stefano; Santangeli, Pasquale; DI Biase, Luigi; Natale, Andrea

2013-01-01

Patients with mechanical "hardware" in the heart, such as those with mechanical cardiac valves or atrial septal closure devices, represent a population at high risk of developing AF. Catheter ablation of AF in these subjects might represent a challenge, due to the perceived higher risk of complications associated with the presence of intracardiac mechanical devices. Accordingly, such patients were excluded or poorly represented in major trials proving the benefit of catheter ablation for the rhythm-control of AF. However, recent evidence supports the concept that catheter ablation procedures might be equally effective in these patients, without a significant increase in the risk of procedural complications. This review will summarize the current state-of-the-art on catheter ablation of AF in patients with mechanical "hardware" in the heart.

Laparoscopic microwave thermosphere ablation of malignant liver tumors: an initial clinical evaluation.

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Berber, Eren

2016-02-01

Microwave ablation (MWA) has been recently recognized as a technology to overcome the limitations of radiofrequency ablation. The aim of the current study was to evaluate the safety and efficacy of a new 2.45-GHz thermosphere MWA system in the treatment of malignant liver tumors. This was a prospective IRB-approved study of 18 patients with malignant liver tumors treated with MWA within a 3-month time period. Tumor sizes and response to MWA were obtained from triphasic liver CT scans done before and after MWA. The ablation zones were assessed for complete tumor response and spherical geometry. There were a total of 18 patients with an average of three tumors measuring 1.4 cm (range 0.2-4). Ablations were performed laparoscopically in all, but three patients who underwent combined liver resection. A single ablation was created in 72% and overlapping ablations in 28% of lesions. Total ablation time per patient was 15.6 ± 1.9 min. There was no morbidity or mortality. At 2-week CT scans, there was 100% tumor destruction, with no residual lesions. Roundness indices A, B and transverse were 1.1, 0.9 and 0.9, respectively, confirming the spherical nature of ablation zones. To the best of our knowledge, this is the first report of a new thermosphere MWA technology in the laparoscopic treatment of malignant liver tumors. The results demonstrate the safety of the technology, with satisfactory spherical ablation zones seen on post-procedural CT scans.

An experimental study of simultaneous ablation with dual probes in radiofrequency thermal ablation

International Nuclear Information System (INIS)

Jang, Il Soo; Rhim, Hyun Chul; Koh, Byung Hee; Cho, On Koo; Seo, Heung Suk; Kim, Yong Soo; Kim, Young Sun; Heo, Jeong Nam

2003-01-01

To determine the differences between sequential ablation with a single probe and simultaneous ablation with dual probes. Using two 14-gauge expandable probes (nine internal prongs with 4-cm deployment), radiofrequency was applied sequentially (n=8) or simultaneously (n=8) to ten ex-vivo cow livers. Before starting ablation, two RF probes with an inter-probe space of 2 cm (n=8) or 3 cm (n=8) were inserted. In the sequential group, switching the connecting cable to an RF generator permitted ablation with the second probe just after ablation with the first probe had finished. In the simultaneous group, single ablation was performed only after connecting the shafts of both RF probes using a connection device. Each ablation lasted 7 minutes at a target temperature of 105-110 .deg. C. The size and shape of the ablated area, and total ablation time were then compared between the two groups. With 2-cm spacing, the group, mean length and overlapping width of ablated lesions were, respectively, 5.20 and 5.05 cm in the sequential group (n=4), and 5.81 and 5.65 cm in the simultaneous group (n=4). With 3-cm spacing, the corresponding figures were 4.99 and 5.60 cm in the sequential group (n=4), and 6.04 and 6.78 cm in the simultaneous group (n=4). With 2-cm spacing, the mean depth of the proximal waist was 0.58 cm in the sequential (group and 0.28 cm in the simultaneous group, while with 3-cm spacing, the corresponding figures were 1.65 and 1.48 cm. In neither group was there a distal waist. Mean total ablation time was 23.4 minutes in the sequential group and 14 minutes in the simultaneous group. In terms of ablation size and ablation time, simultaneous radiofrequency ablation with dual probes is superior to sequential ablation with a single probe. A simultaneous approach will enable an operator to overcome difficulty in probe repositioning during overlapping ablation, resulting in complete ablation with a successful safety margin

Mexametric and cutometric assessment of the signs of aging of the skin area around the eyes after the use of non-ablative fractional laser, non-ablative radiofrequency and intense pulsed light.

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Kołodziejczak, Anna Maria; Rotsztejn, Helena

2017-03-01

The assessment of the signs of aging within eyes area in cutometric (skin elasticity) and mexametric (discoloration and severity of erythema) examination after the treatment with: non-ablative fractional laser, non-ablative radiofrequency (RF) and intense light source (IPL). This study included 71 patients, aged 33-63 years (the average age was 45.81) with Fitzpatrick skin type II and III. 24 patients received 5 successive treatment sessions with a 1,410-nm non-ablative fractional laser in two-week intervals, 23 patients received 5 successive treatment sessions with a non-ablative RF in one-week intervals and 24 patients received 5 successive treatment sessions with an IPL in two-week intervals. The treatment was performed for the skin in the eye area. The Cutometer and Mexameter (Courage + Khazaka electronic) reference test was used as an objective method for the assessment of skin properties: elasticity, skin pigmentation and erythema. Measurements of skin elasticity were made in three or four sites within eye area. The results of cutometric measurements for R7 showed the improvement in skin elasticity in case of all treatment methods. The largest statistically significant improvement (p measurements and for all methods, the greatest improvement in skin elasticity was demonstrated between the first and second measurement (after 3rd procedures). The majority of the results of mexametric measurements-MEX (melanin level) and ERYT (the severity of erythema) are statistically insignificant. Fractional, non-ablative laser, non-ablation RF and intense light source can be considered as methods significantly affecting elasticity and to a lesser extent erythema and skin pigmentation around the eyes. Fractional non-ablative laser is a method which, in comparison to other methods, has the greatest impact on skin viscoelasticity. These procedures are well tolerated and are associated with a low risk of side effects. © 2017 Wiley Periodicals, Inc.

Effects of an early experience involving training in a T-maze under either denial or receipt of expected reward through maternal contact.

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Antonios eStamatakis

2013-11-01

Full Text Available The mother is the most salient stimulus for the developing pups and a number of early experience models employ manipulation of the mother-infant interaction. We have developed a new model which in addition to changes in maternal behavior includes a learning component on the part of the pups. More specifically, pups were trained in a T-maze and either received (RER rats or were denied (DER the reward of maternal contact, during postnatal days 10—13.Pups of both experimental groups learn the T-maze, but the RER do so more efficiently utilizing a procedural-type of learning and memory with activation of the dorsal basal ganglia. On the other hand, the DER experience leads to activation of the hippocampus, prefrontal cortex and amygdala in the pups.In adulthood, male DER animals exhibit better mnemonic abilities in the Morris water maze and higher activation of the hippocampus, while they have decreased brain serotonergic activity, exhibit a depressive-like phenotype and proactive aggressive behavior in the resident-intruder test. On the other hand, male RER animals assume a reactive coping style in this test, showed increased emotionality as well as freezing in the memory test following both contextual and cued fear conditioning.

Ablation mass features in multi-pulses femtosecond laser ablate molybdenum target

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Zhao, Dongye; Gierse, Niels; Wegner, Julian; Pretzler, Georg; Oelmann, Jannis; Brezinsek, Sebastijan; Liang, Yunfeng; Neubauer, Olaf; Rasinski, Marcin; Linsmeier, Christian; Ding, Hongbin

2018-03-01

In this study, the ablation mass features related to reflectivity of bulk Molybdenum (Mo) were investigated by a Ti: Sa 6 fs laser pulse at central wavelength 790 nm. The ablated mass removal was determined using Confocal Microscopy (CM) technique. The surface reflectivity was calibrated and measured by a Lambda 950 spectrophotometer as well as a CCD camera during laser ablation. The ablation mass loss per pulse increase with the increasing of laser shots, meanwhile the surface reflectivity decrease. The multi-pulses (100 shots) ablation threshold of Mo was determined to be 0.15 J/cm2. The incubation coefficient was estimated as 0.835. The reflectivity change of the Mo target surface following multi-pulses laser ablation were studied as a function of laser ablation shots at various laser fluences from 1.07 J/cm2 to 36.23 J/cm2. The results of measured reflectivity indicate that surface reflectivity of Mo target has a significant decline in the first 3-laser pulses at the various fluences. These results are important for developing a quantitative analysis model for laser induced ablation and laser induced breakdown spectroscopy for the first wall diagnosis of EAST tokamak.

Bipolar radiofrequency ablation of liver metastases during laparotomy. First clinical experiences with a new multipolar ablation concept.

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Ritz, Joerg-Peter; Lehmann, Kai S; Reissfelder, Christoph; Albrecht, Thomas; Frericks, Bernd; Zurbuchen, Urte; Buhr, Heinz J

2006-01-01

Radiofrequency ablation (RFA) is a promising method for local treatment of liver malignancies. Currently available systems for radiofrequency ablation use monopolar current, which carries the risk of uncontrolled electrical current paths, collateral damages and limited effectiveness. To overcome this problem, we used a newly developed internally cooled bipolar application system in patients with irresectable liver metastases undergoing laparotomy. The aim of this study was to clinically evaluate the safety, feasibility and effectiveness of this new system with a novel multipolar application concept. Patients with a maximum of five liver metastases having a maximum diameter of 5 cm underwent laparotomy and abdominal exploration to control resectability. In cases of irresectability, RFA with the newly developed bipolar application system was performed. Treatment was carried out under ultrasound guidance. Depending on tumour size, shape and location, up to three applicators were simultaneously inserted in or closely around the tumour, never exceeding a maximum probe distance of 3 cm. In the multipolar ablation concept, the current runs alternating between all possible pairs of consecutively activated electrodes with up to 15 possible electrode combinations. Post-operative follow-up was evaluated by CT or MRI controls 24-48 h after RFA and every 3 months. In a total of six patients (four male, two female; 61-68 years), ten metastases (1.0-5.5 cm) were treated with a total of 14 RF applications. In four metastases three probes were used, and in another four and two metastases, two and one probes were used, respectively. During a mean ablation time of 18.8 min (10-31), a mean energy of 48.8 kJ (12-116) for each metastases was applied. No procedure-related complications occurred. The patients were released from the hospital between 7 and 12 days post-intervention (median 9 days). The post-interventional control showed complete tumour ablation in all cases. Bipolar

Results of radiofrequency ablation of liver tumors: experience of 134 cases

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Marcelo Augusto Fontenelle Ribeiro Junior

2008-12-01

Full Text Available Objective: To study radiofrequency ablation of primary and metastatic livertumors. Methods: The authors present a series of 134 cases, 63 femalesand 71 males with a mean age of 61.2 years, in whom radiofrequencyablation was used either by laparotomy or percutaneously to treat 203lesions. The group was composed of 51 cases of hepatocellular carcinoma,four cases of cholangiocarcinoma, and cases of hepatic metastases, asfollows: 64 of colorectal cancer, 6 of neuroendocrine tumors, 5 of breastcancer, 1 case of pancreas cancer, 1 of kidney cancer, 1 of endometrialcancer and 1 of leiomyosarcoma. Results: Procedure-associatedmorbidity/mortality was 24.8 and 3.7%, respectively. Recurrence wasobserved in 12.7% within a mean time of 10.5 months. Conclusions:Radiofrequency ablation is a safe procedure and can be used in patientswith impaired hepatic function. For metastatic diseases, it does notreplace surgery but it can be associated with other procedures, such assurgery and transarterial chemoembolization, or after recurrence, leadingto greater probability of remaining disease-free.

Echocardiography-guided Radiofrequency Catheter Ablation of Atrioventricular Node and VVI Pacemaker Implantation

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T Guo

2014-05-01

Full Text Available Objective: This study is to evaluate the feasibility and safety of intracardiac radiofrequency catheter ablation (RFCA of the atrioventricular node (AVN and pacemaker implantation using transthoracic echocardiography. Methods: Eleven patients – six males and five females (mean age 66 years – with persistent or permanent atrial fibrillation/atrial flutter received RFCA of AVN and VVI pacemaker implantation (paces and senses the ventricle and is inhibited if it senses ventricular activity. Under transthoracic echocardiography, the electrode catheters were positioned intracardiac, and target ablation was performed, with the permanent pacemaking catheter in the left subclavian vein and the ablation catheter in the right femoral vein. The multi-view imaging and dynamic observation applied during the stable AV dissociation were successful. Results: Atrioventricular node ablation and permanent pacemaker implantation in 11 patients were completed successfully without X-ray exposure. The operation success rate was 100%. All patients recovered well within the follow-up period. Conclusions: Radiofrequency catheter ablation of AVN and VVI pacemaker implantation under transthoracic echocardiography guidance is a safe, easy and feasible approach. This procedure could be an important supplemental measure to catheter ablation of arrhythmia under routine X-ray fluoroscopy.

Growth rates of the ablative Rayleigh endash Taylor instability in inertial confinement fusion

International Nuclear Information System (INIS)

Betti, R.; Goncharov, V.N.; McCrory, R.L.; Verdon, C.P.

1998-01-01

A simple procedure is developed to determine the Froude number Fr, the effective power index for thermal conduction ν, the ablation-front thickness L 0 , the ablation velocity V a , and the acceleration g of laser-accelerated ablation fronts. These parameters are determined by fitting the density and pressure profiles obtained from one-dimensional numerical simulations with the analytic isobaric profiles of Kull and Anisimov [Phys. Fluids 29, 2067 (1986)]. These quantities are then used to calculate the growth rate of the ablative Rayleigh endash Taylor instability using the theory developed by Goncharov et al. [Phys. Plasmas 3, 4665 (1996)]. The complicated expression of the growth rate (valid for arbitrary Froude numbers) derived by Goncharov et al. is simplified by using reasonably accurate fitting formulas. copyright 1998 American Institute of Physics

Chemical nonequilibrium Navier-Stokes solutions for hypersonic flow over an ablating graphite nosetip

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Chen, Y. K.; Henline, W. D.

1993-01-01

The general boundary conditions including mass and energy balances of chemically equilibrated or nonequilibrated gas adjacent to ablating surfaces have been derived. A computer procedure based on these conditions was developed and interfaced with the Navier-Stokes solver for predictions of the flow field, surface temperature, and surface ablation rates over re-entry space vehicles with ablating Thermal Protection Systems (TPS). The Navier-Stokes solver with general surface thermochemistry boundary conditions can predict more realistic solutions and provide useful information for the design of TPS. A test case with a proposed hypersonic test vehicle configuration and associated free stream conditions was developed. Solutions with various surface boundary conditions were obtained, and the effect of nonequilibrium gas as well as surface chemistry on surface heating and ablation rate were examined. The solutions of the GASP code with complete ablating surface conditions were compared with those of the ASC code. The direction of future work is also discussed.

CBM Maze-Scores as Indicators of Reading Level and Growth for Seventh-Grade Students

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Chung, Siuman; Espin, Christine A.; Stevenson, Claire E.

2018-01-01

The technical adequacy of CBM maze-scores as indicators of reading level and growth for seventh-grade secondary-school students was examined. Participants were 452 Dutch students who completed weekly maze measures over a period of 23 weeks. Criterion measures were school level, dyslexia status, scores and growth on a standardized reading test.…

Heart-type fatty acid binding protein is an early marker of myocardial damage after radiofrequency catheter ablation.

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Giannessi, Daniela; Piacenti, Marcello; Maltinti, Maristella; Rossi, Andrea; Di Cecco, Pietro; Startari, Umberto; Cabiati, Manuela; Panchetti, Luca; Del Ry, Silvia; Morales, Maria-Aurora

2010-10-01

Radiofrequency (RF) ablation of arrhythmias induces myocardial damage and release of biomarkers. This study aimed to assess the kinetics of heart-type fatty acid-binding protein (h-FABP), a cytosolic protein released after myocardial injury incurred by both atrial and ventricular RF ablation, compared to other markers of myocardial injury. h-FABP, cTnI, CK-MB(mass) and myoglobin were evaluated in 30 patients with atrial or ventricular tachyarrhythmias before, immediately after and at 3, 6 and 24h after the procedure. h-FABP increased immediately after the procedure in all subjects (6.6 ± 1.2 μg/L vs 2.7 ± 0.3, pvalues of time for mean power of RF application in both the entire patient cohort and in ventricular ablations. h-FABP may be an early parameter for monitoring RF-induced lesions and the site of ablation was relevant for biomarker increase. Copyright © 2010 Elsevier Inc. All rights reserved.

Anatomic characterization of cavotricuspid isthmus by 3D transesophageal echocardiography in patients undergoing radiofrequency ablation of typical atrial flutter.

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Regoli, François; Faletra, Francesco; Marcon, Serena; Leo, Laura Anna; Dequarti, Maria Cristina; Caputo, Maria Luce; Conte, Giulio; Moccetti, Tiziano; Auricchio, Angelo

2018-01-01

Radiofrequency ablation (RFA) is the treatment of choice of cavotricuspid isthmus (CTI)-dependent atrial flutter. Procedural time is highly variable due to anatomical structures. This study aimed to characterize CTI anatomy by transesophageal 3D echocardiography imaging (3D-TEE) to identify anatomic structures related to longer ablation time. Thirty-one consecutive patients (mean age 67.3 ± 11.5 years, 22 males) underwent CTI-ablation procedure. Before ablation, TEE was performed and 3D-TEE images were acquired to evaluate CTI anatomy qualitatively as well as perform measures of CTI morphological features. The electrophysiologist performing RFA was blinded to 3D-TEE data. Bidirectional block of CTI was achieved in all patients without procedural complications after a median ablation time of 11 (IQR 7-14) min. Patients with RFA time ≥11 min (Group 2) presented lower left ventricular ejection fraction (51.1 ± 17.0 vs. 59.5 ± 6.6%, P 3D-TEE imaging is extremely helpful in qualitative and quantitative evaluation of CTI anatomy in patients undergoing RFA for symptomatic typical atrial flutter. Detection of a deep right atrial pouch was found to be associated with significantly prolonged CTI ablation time to achieve bidirectional block. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions, please email: journals.permissions@oup.com.

Radiofrequency ablation of hepatocellular carcinoma located in the liver dome under intermittent CT fluoroscopy guidance

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Park, Darlene; Cho, Yun Ku; Cho, Hyun Je; KIm, Mi Young [Dept. of Radiology, VHS Medical Center, Seoul (Korea, Republic of)

2014-02-15

To evaluate the clinical effectiveness of an intermittent computed tomography (CT) fluoroscopy-guided radiofrequency (RF) ablation of hepatocellular carcinoma located in the liver dome. Between 2005 and 2010 23 patients with hepatocellular carcinoma (HCC) nodules located in the liver dome underwent an intermittent CT fluoroscopy-guided RF ablation. The primary endpoint was the local tumor progression. Procedure-related complications occurred in 3 of 23 patients. To evaluate the prognostic factors for the local tumor progression, univariate and multivariate analyses were performed using the Cox proportional hazards model. The chi-squared test was performed to evaluate the association of access route and procedure-related complication. The study was approved by the Institutional Review Board of our hospital. The Tumor sizes ranged between 1.0 and 2.9 cm. An initial complete ablation was achieved in all patients. The median follow-up period was 31 months and the major complication rate was 4.3%. The cumulative rate of local tumor progression at 3 years was 20%. The univariate analysis revealed that only serum total bilirubin level (p = 0.048) and prior chemoembolization were statistically significant (p = 0.044), but there was no independently significant prognostic factor on multivariate analysis. Procedure-related complications occurred in 3 of 23 patients. For HCC located in the liver dome an intermittent CT fluoroscopy-guided RF ablation could be performed safely and effectively.

Pulmonary vein region ablation in experimental vagal atrial fibrillation: role of pulmonary veins versus autonomic ganglia.

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Lemola, Kristina; Chartier, Denis; Yeh, Yung-Hsin; Dubuc, Marc; Cartier, Raymond; Armour, Andrew; Ting, Michael; Sakabe, Masao; Shiroshita-Takeshita, Akiko; Comtois, Philippe; Nattel, Stanley

2008-01-29

Pulmonary vein (PV) -encircling radiofrequency ablation frequently is effective in vagal atrial fibrillation (AF), and there is evidence that PVs may be particularly prone to cholinergically induced arrhythmia mechanisms. However, PV ablation procedures also can affect intracardiac autonomic ganglia. The present study examined the relative role of PVs versus peri-PV autonomic ganglia in an experimental vagal AF model. Cholinergic AF was studied under carbachol infusion in coronary perfused canine left atrial PV preparations in vitro and with cervical vagal stimulation in vivo. Carbachol caused dose-dependent AF promotion in vitro, which was not affected by excision of all PVs. Sustained AF could be induced easily in all dogs during vagal nerve stimulation in vivo both before and after isolation of all PVs with encircling lesions created by a bipolar radiofrequency ablation clamp device. PV elimination had no effect on atrial effective refractory period or its responses to cholinergic stimulation. Autonomic ganglia were identified by bradycardic and/or tachycardic responses to high-frequency subthreshold local stimulation. Ablation of the autonomic ganglia overlying all PV ostia suppressed the effective refractory period-abbreviating and AF-promoting effects of cervical vagal stimulation, whereas ablation of only left- or right-sided PV ostial ganglia failed to suppress AF. Dominant-frequency analysis suggested that the success of ablation in suppressing vagal AF depended on the elimination of high-frequency driver regions. Intact PVs are not needed for maintenance of experimental cholinergic AF. Ablation of the autonomic ganglia at the base of the PVs suppresses vagal responses and may contribute to the effectiveness of PV-directed ablation procedures in vagal AF.

Un cas particulier du scénario dans l'apprentissage des langues : le labyrinthe (action maze Action Mazes: a special case of the scenario for language learning

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Joseph Rézeau

2008-03-01

Full Text Available En didactique des langues l'approche actionnelle et les scénarios sont d'actualité, en lien avec les Tice (Technologies de l'Information et de la Communication pour l'Enseignement. Cependant, des activités de type labyrinthe (action mazes, courantes dans les années 1980 et souvent portées sur les micro-ordinateurs de l'époque, semblent quelque peu tombées dans l'oubli. Cet article entend montrer qu'il est relativement aisé de concevoir et de réaliser de telles activités sur une plateforme d'enseignement à distance telle que Moodle. Nous analyserons également l'impact d'une activité de type labyrinthe sur une population d'étudiants dans le cadre d'un enseignement d'anglais de type Lansad (langues pour spécialistes d'autres disciplines.The development of ICT in language teaching concurs with an interest in task-based approaches and scenarios. Surprisingly, however, such activities as "adventure games" and "action mazes" which were quite popular in CALL (Computer Assisted Language Learning in the 1980s seem to have fallen into oblivion. This article aims at demonstrating that it is relatively easy to design and implement "action mazes" on an LMS (Learning Management System such as Moodle. We shall then analyse the impact of an "action maze" learning activity on a population of students of ESP (English for Specific Purposes.

The effect of a paraffin screen on the neutron dose at the maze door of a 15 MV linear accelerator.

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Krmar, M; Nikolić, D; Kuzmanović, A; Kuzmanović, Z; Ganezer, K

2013-08-01

The purpose of this study was to explore the effects of a paraffin screen located at various positions in the maze on the neutron dose equivalent at the maze door. The neutron dose equivalent was measured at the maze door of a room containing a 15 MV linear accelerator for x-ray therapy. Measurements were performed for several positions of the paraffin screen covering only 27.5% of the cross-sectional area of the maze. The neutron dose equivalent was also measured at all screen positions. Two simple models of the neutron source were considered in which the first assumed that the source was the cross-sectional area at the inner entrance of the maze, radiating neutrons in an isotropic manner. In the second model the reduction in the neutron dose equivalent at the maze door due to the paraffin screen was considered to be a function of the mean values of the neutron fluence and energy at the screen. The results of this study indicate that the equivalent dose at the maze door was reduced by a factor of 3 through the use of a paraffin screen that was placed inside the maze. It was also determined that the contributions to the dosage from areas that were not covered by the paraffin screen as viewed from the dosimeter, were 2.5 times higher than the contributions from the covered areas. This study also concluded that the contributions of the maze walls, ceiling, and floor to the total neutron dose equivalent were an order of magnitude lower than those from the surface at the far end of the maze. This study demonstrated that a paraffin screen could be used to reduce the neutron dose equivalent at the maze door by a factor of 3. This paper also found that the reduction of the neutron dose equivalent was a linear function of the area covered by the maze screen and that the decrease in the dose at the maze door could be modeled as an exponential function of the product φ·E at the screen.

Contact force sensing for ablation of persistent atrial fibrillation: A randomized, multicenter trial.

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Conti, Sergio; Weerasooriya, Rukshen; Novak, Paul; Champagne, Jean; Lim, Hong Euy; Macle, Laurent; Khaykin, Yaariv; Pantano, Alfredo; Verma, Atul

2018-02-01

Impact of contact force sensing (CFS) on ablation of persistent atrial fibrillation (PeAF) is unknown. The purpose of the TOUCH AF (Therapeutic Outcomes Using Contact force Handling during Ablation of Persistent Atrial Fibrillation) randomized trial was to compare CFS-guided ablation to a CFS-blinded strategy. Patients (n = 128) undergoing first-time ablation for persistent AF were randomized to a CFS-guided vs CFS-blinded strategy. In the CFS-guided procedure, operators visualized real-time force data. In the blinded procedure, force data were hidden. Wide antral pulmonary vein isolation plus a roof line were performed. Patients were followed at 3, 6, 9, and 12 months with clinical visit, ECG, and 48-hour Holter monitoring. The primary endpoint was cumulative radiofrequency (RF) time for all procedures. Atrial arrhythmia >30 seconds after 3 months was a recurrence. PeAF was continuous for 26 weeks (interquartile range [IQR] 13-52), and left atrial size was 45 ± 5 mm. Force in the CFS-blinded and CFS-guided arms was 12 g [IQR 6-20] and 14 g [IQR 9-20] (P = .10), respectively. Total RF time did not differ between CFS-guided and CFS-blinded groups (49 ± 14 min vs 50 ± 20 min, respectively; P = .70). Single procedure freedom from atrial arrhythmia was 60% in the CFS-guided arm and 63% in the CFS-blinded arm off drugs. Lesions with gaps were associated with significantly less force (11.4 g [IQR 6-19] vs 13.2 g [IQR 8-20], respectively; P = .0007) and less force-time integral (174 gs [IQR 91-330] vs 210 gs [IQR 113-388], respectively; P force/force-time integral was associated with significantly more gaps. Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Sex differences in vicarious trial-and-error behavior during radial arm maze learning.

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Bimonte, H A; Denenberg, V H

2000-02-01

We investigated sex differences in VTE behavior in rats during radial arm maze learning. Females made more VTEs than males, although there were no sex differences in learning. Further, VTEs and errors were positively correlated during the latter testing sessions in females, but not in males. This sex difference may be a reflection of differences between the sexes in conflict behavior or cognitive strategy while solving the maze.

Radiofrequency Ablation of Lung Tumors

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... News Physician Resources Professions Site Index A-Z Radiofrequency Ablation (RFA) / Microwave Ablation (MWA) of Lung Tumors ... and Microwave Ablation of Lung Tumors? What are Radiofrequency and Microwave Ablation of Lung Tumors? Radiofrequency ablation, ...

Microjet-assisted dye-enhanced diode laser ablation of cartilaginous tissue

Science.gov (United States)

Pohl, John; Bell, Brent A.; Motamedi, Massoud; Frederickson, Chris J.; Wallace, David B.; Hayes, Donald J.; Cowan, Daniel

1994-08-01

Recent studies have established clinical application of laser ablation of cartilaginous tissue. The goal of this study was to investigate removal of cartilaginous tissue using diode laser. To enhance the interaction of laser light with tissue, improve the ablation efficiency and localize the extent of laser-induced thermal damage in surrounding tissue, we studied the use of a novel delivery system developed by MicroFab Technologies to dispense a known amount of Indocyanine Green (ICG) with a high spatial resolution to alter the optical properties of the tissue in a controlled fashion. Canine intervertebral disks were harvested and used within eight hours after collection. One hundred forty nL of ICG was topically applied to both annulus and nucleus at the desired location with the MicroJet prior to each irradiation. Fiber catheters (600 micrometers ) were used and positioned to irradiate the tissue with a 0.8 mm spot size. Laser powers of 3 - 10 W (Diomed, 810 nm) were used to irradiate the tissue with ten pulses (200 - 500 msec). Discs not stained with ICG were irradiated as control samples. Efficient tissue ablation (80 - 300 micrometers /pulse) was observed using ICG to enhance light absorption and confine thermal damage while there was no observable ablation in control studied. The extent of tissue damage observed microscopically was limited to 50 - 100 micrometers . The diode laser/Microjet combination showed promise for applications involving removal of cartilaginous tissue. This procedure can be performed using a low power compact diode laser, is efficient, and potentially more economical compared to procedures using conventional lasers.

Radiation dose electrophysiology procedures

International Nuclear Information System (INIS)

Hernandez-Armas, J.; Rodriguez, A.; Catalan, A.; Hernandez Armas, O.; Luque Japon, L.; Moral, S.; Barroso, L.; Rfuez-Hdez, R.

2006-01-01

The aim of this paper has been to measure and analyse some of the parameters which are directly related with the doses given to patients in two electrophysiology procedures: diagnosis and ablation with radiofrequency. 16 patients were considered in this study. 13 them had an ablation with radiofrequency at the Unit of Electrophysiology at the University Hospital of the Canaries, La Laguna., Tenerife. The results of skin doses, in the ablation cases, were higher than 2 Gy (threshold of some deterministic effects). The average value was 1.1 Gy. The personal doses, measured under the lead apron, for physician and nurses were 4 and 3 micro Sievert. These results emphasised the necessity of radiation protection measures in order to reduce, ad much as possible, the doses to patients. (Author)

Endometrial ablation in the management of abnormal uterine bleeding.

Science.gov (United States)

Laberge, Philippe; Leyland, Nicholas; Murji, Ally; Fortin, Claude; Martyn, Paul; Vilos, George; Leyland, Nicholas; Wolfman, Wendy; Allaire, Catherine; Awadalla, Alaa; Dunn, Sheila; Heywood, Mark; Lemyre, Madeleine; Marcoux, Violaine; Potestio, Frank; Rittenberg, David; Singh, Sukhbir; Yeung, Grace

2015-04-01

, preoperative and postoperative care, operative set-up, anaesthesia, and practical considerations for practice. Implementation of the guideline recommendations will improve the provision of EA as an effective treatment of AUB. Following these recommendations would allow the surgical procedure to be performed safely and maximize success for patients. EA is a safe and effective minimally invasive option for the treatment of AUB of benign etiology. Summary Statements 1. Endometrial ablation is a safe and effective minimally invasive surgical procedure that has become a well-established alternative to medical treatment or hysterectomy to treat abnormal uterine bleeding in select cases. (I) 2. Endometrial preparation can be used to facilitate resectoscopic endometrial ablation (EA) and can be considered for some non-resectoscopic techniques. For resectoscopic EA, preoperative endometrial thinning results in higher short-term amenorrhea rates, decreased irrigant fluid absorption, and shorter operative time than no treatment. (I) 3. Non-resectoscopic techniques are technically easier to perform than resectoscopic techniques, have shorter operative times, and allow the use of local rather than general anaesthesia. However, both techniques have comparable patient satisfaction and reduction of heavy menstrual bleeding. (I) 4. Both resectoscopic and non-resectoscopic endometrial ablation (EA) have low complication rates. Uterine perforation, fluid overload, hematometra, and cervical lacerations are more common with resectoscopic EA; perioperative nausea/vomiting, uterine cramping, and pain are more common with non-resectoscopic EA. (I) 5. All non-resectoscopic endometrial ablation devices available in Canada have demonstrated effectiveness in decreasing menstrual flow and result in high patient satisfaction. The choice of which device to use depends primarily on surgical judgement and the availability of resources. (I) 6. The use of local anaesthetic and blocks, oral analgesia, and

Long-wave plasma radiofrequency ablation for treatment of xanthelasma palpebrarum.

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Baroni, Adone

2018-03-01

Xanthelasma palpebrarum is the most common type of xanthoma affecting the eyelids. It is characterized by asymptomatic soft yellowish macules, papules, or plaques over the upper and lower eyelids. Many treatments are available for management of xanthelasma palpebrarum, the most commonly used include surgical excision, ablative CO 2 or erbium lasers, nonablative Q-switched Nd:YAG laser, trichloroacetic acid peeling, and radiofrequency ablation. This study aims to evaluate the effectiveness of RF ablation in the treatment of xanthelasma palpebrarum, with D.A.S. Medical portable device (Technolux, Italia), a radiofrequency tool working with long-wave plasma energy and without anesthesia. Twenty patients, 15 female and 5 male, affected by xanthelasma palpebrarum, were enrolled for long-wave plasma radiofrequency ablation treatment. The treatment consisted of 3/4 sessions that were carried out at intervals of 30 days. Treatments were well tolerated by all patients with no adverse effects and optimal aesthetic results. The procedure is very fast and can be performed without anesthesia because of the low and tolerable pain stimulation. Long-wave plasma radiofrequency ablation is an effective option for treatment of xanthelasma palpebrarum and adds an additional tool to the increasing list of medical devices for aesthetic treatments. © 2018 Wiley Periodicals, Inc.

[Catheter ablation in patients with refractory cardiac arrhythmias with radiofrequency techniques].

Science.gov (United States)

de Paola, A A; Balbão, C E; Silva Netto, O; Mendonça, A; Villacorta, H; Vattimo, A C; Souza, I A; Guiguer Júnior, N; Portugal, O P; Martinez Filho, E E

1993-02-01

evaluate the efficacy of radiofrequency catheter ablation in patients with refractory cardiac arrhythmias. twenty patients with refractory cardiac arrhythmias were undertaken to electrophysiologic studies for diagnosis and radiofrequency catheter ablation of their reentrant arrhythmias. Ten patients were men and 10 women with ages varying from 13 to 76 years (mean = 42.4 years). Nineteen patients had supraventricular tachyarrhythmias: One patient had atrial tachycardia and 1 atrial fibrillation with rapid ventricular rate, 5 patients had reentrant nodal tachycardia, 12 patients had reentrant atrioventricular tachycardia and 1 patient had right ventricular outflow tract tachycardia. the mean time of the procedure was 4.1 hours. The radiofrequency current energy applied was 40-50 V for 30-40 seconds. Ablation was successful in 18/20 (90%) patients; in 15/18 (83%) of successfully treated patients the same study was done for diagnosis and radiofrequency ablation. One patient had femoral arterial occlusion and was treated with no significant sequelae. During a mean follow-up of 4 months no preexcitation or reentrant tachycardia occurred. the results of our experience with radiofrequency catheter ablation of cardiac arrhythmias suggest that this technique can benefit an important number of patients with cardiac arrhythmias.

Percutaneous local ablation of unifocal subclinical breast cancer: clinical experience and preliminary results of cryotherapy

Energy Technology Data Exchange (ETDEWEB)

Manenti, Guglielmo; Perretta, Tommaso; Gaspari, Eleonora; Pistolese, Chiara A.; Scarano, Lia; Cossu, Elsa; Simonetti, Giovanni; Masala, Salvatore [University Hospital ' ' Tor Vergata' ' , Department of Diagnostic Imaging and Interventional Radiology, Molecular Imaging and Radiotherapy, Rome (Italy); Bonanno, Elena [University Hospital ' ' Tor Vergata' ' , Department of Biopathology, Rome (Italy); Buonomo, Oreste C.; Petrella, Giuseppe [University Hospital ' ' Tor Vergata' ' , Department of General Surgery Division, Rome (Italy)

2011-11-15

To assess the ablative effectiveness, the oncological and cosmetic efficacy of image-guided percutaneous cryoablation in the treatment of single breast nodules with subclinical dimensions after identification with ultrasonography (US), mammography, magnetic resonance (MRI) and characterization by vacuum assisted biopsy. Fifteen women with a mean age of 73 {+-} 5 years (range 64-82 years) and lesion diameter of 8 {+-} 4 mm were undergoing cryotherapy technology with a single probe under US-guidance associated with intra-procedural lymph-node mapping and excision of the sentinel node. All the patients underwent surgical resection (lumpectomy) from 30 to 45 days after the percutaneous ablation. The iceball size generated by the cryoprobe during the procedure at minus 40 C was 16 x 41 mm. In 14 of the 15 patients was observed a complete necrosis of the cryo-ablated lesion both in post-procedural MRI follow-up and anatomo-pathological evaluation after surgical resection. In one case there was a residual disease in post-procedural MRI and postoperative histological examination, probably justified by an incorrect positioning of the probe. The percutaneous cryoablation as a ''minimally invasive'' technique can provide excellent oncological and cosmetic results on selected cases handled by experienced operators by using the tested devices. (orig.)

Percutaneous local ablation of unifocal subclinical breast cancer: clinical experience and preliminary results of cryotherapy

International Nuclear Information System (INIS)

Manenti, Guglielmo; Perretta, Tommaso; Gaspari, Eleonora; Pistolese, Chiara A.; Scarano, Lia; Cossu, Elsa; Simonetti, Giovanni; Masala, Salvatore; Bonanno, Elena; Buonomo, Oreste C.; Petrella, Giuseppe

2011-01-01

To assess the ablative effectiveness, the oncological and cosmetic efficacy of image-guided percutaneous cryoablation in the treatment of single breast nodules with subclinical dimensions after identification with ultrasonography (US), mammography, magnetic resonance (MRI) and characterization by vacuum assisted biopsy. Fifteen women with a mean age of 73 ± 5 years (range 64-82 years) and lesion diameter of 8 ± 4 mm were undergoing cryotherapy technology with a single probe under US-guidance associated with intra-procedural lymph-node mapping and excision of the sentinel node. All the patients underwent surgical resection (lumpectomy) from 30 to 45 days after the percutaneous ablation. The iceball size generated by the cryoprobe during the procedure at minus 40 C was 16 x 41 mm. In 14 of the 15 patients was observed a complete necrosis of the cryo-ablated lesion both in post-procedural MRI follow-up and anatomo-pathological evaluation after surgical resection. In one case there was a residual disease in post-procedural MRI and postoperative histological examination, probably justified by an incorrect positioning of the probe. The percutaneous cryoablation as a ''minimally invasive'' technique can provide excellent oncological and cosmetic results on selected cases handled by experienced operators by using the tested devices. (orig.)

Is there still a role for additional linear ablation in addition to pulmonary vein isolation in patients with paroxysmal atrial fibrillation? An Updated Meta-analysis of randomized controlled trials.

Science.gov (United States)

Hu, Xiaoliang; Jiang, Jingzhou; Ma, Yuedong; Tang, Anli

2016-04-15

The benefits and risks of additional left atrium (LA) linear ablation in patients with paroxysmal atrial fibrillation (AF) remain unclear. Randomized controlled trials were identified in the PubMed, Web of Science, Embase and Cochrane databases, and the relevant papers were examined. Pooled relative risks (RR) and 95% confidence interval (95% CI) were estimated using random effects models. The primary endpoint was the maintenance of sinus rhythm after a single ablation. Nine randomized controlled trials involving 1138 patients were included in this analysis. Additional LA linear ablation did not improve the maintenance of the sinus rhythm following a single procedure (RR, 1.03; 95% CI, 0.93-1.13; P=0.60). A subgroup analysis demonstrated that all methods of additional linear ablation failed to improve the outcome. Additional linear ablation significantly increased the mean procedural time (166.53±67.7 vs. 139.57±62.44min, Plinear ablation did not exhibit any benefits in terms of sinus rhythm maintenance for paroxysmal AF patients following a single procedure. Additional linear ablation significantly increased the mean procedural, fluoroscopy and RF application times. This additional ablation was not associated with a statistically significant increase in complication rates. This finding must be confirmed by further large, high-quality clinical trials. Copyright © 2016. Published by Elsevier Ireland Ltd.

Efficacy and safety of radiofrequency ablation of hepatocellular carcinoma in the hepatic dome with the CT-guided extrathoracic transhepatic approach

International Nuclear Information System (INIS)

Kim, Young Kon; Kim, Chong Soo; Lee, Jeong Min; Chung, Gyung Ho; Chon, Su Bin

2006-01-01

Purpose: The purpose of this study was to determine the efficacy and safety of radiofrequency (RF) ablation for the treatment of hepatocellular carcinoma (HCC) in the hepatic dome with CT-guided extrathoracic transhepatic approach. Materials and methods: Fifteen patients with 15 HCCs (size range: 0.8-4 cm, mean size: 1.8 cm) in the hepatic dome were treated by RF ablation using cooled-tip electrodes and with CT-guided extrathoracic transhepatic approach. Therapeutic response of the tumor to RF ablation and procedure-related complications including hepatic injury, hemoperitoneum, and thermal injury of diaphragm were evaluated. Results: The average number of needle punctures to ensure the correct needle position in the targeted tumor was 3.7 (range: 1-6 punctures). The average ablation time was 14.7 min (range: 8-25 min). Complete necrosis without marginal recurrence after at least 13-month follow-up was attained in 13 tumors (86.7%). There were no major complications related to the procedures. Six patients had shoulder pain that lasted three days to two weeks after the procedures and their symptoms were resolved with conservative treatment. Conclusions: RF ablation using CT-guided extrathoracic transhepatic approach is an effective and safe technique for the treatment of HCC in the hepatic dome

Local ablation therapy with contrast-enhanced ultrasonography for hepatocellular carcinoma: a practical review

Directory of Open Access Journals (Sweden)

Tae Kyoung Kim

2015-10-01

Full Text Available A successful program for local ablation therapy for hepatocellular carcinoma (HCC requires extensive imaging support for diagnosis and localization of HCC, imaging guidance for the ablation procedures, and post-treatment monitoring. Contrast-enhanced ultrasonography (CEUS has several advantages over computed tomography/magnetic resonance imaging (CT/MRI, including real-time imaging capability, sensitive detection of arterial-phase hypervascularity and washout, no renal excretion, no ionizing radiation, repeatability, excellent patient compliance, and relatively low cost. CEUS is useful for image guidance for isoechoic lesions. While contrast-enhanced CT/MRI is the standard method for the diagnosis of HCC and post-ablation monitoring, CEUS is useful when CT/MRI findings are indeterminate or CT/MRI is contraindicated. This article provides a practical review of the role of CEUS in imaging algorithms for pre- and post-ablation therapy for HCC.

Multimodality imaging to guide cardiac interventional procedures

NARCIS (Netherlands)

Tops, Laurens Franciscus

2010-01-01

In recent years, a number of new cardiac interventional procedures have been introduced. Catheter ablation procedures for atrial fibrillation (AF) have been refined and are now considered a good treatment option in patients with drug-refractory AF. In cardiac pacing, cardiac resynchronization

Increased preference of surface ablation over laser in situ keratomileusis between 2008–2011 is correlated to risk of ecatasia

Directory of Open Access Journals (Sweden)

Moisseiev E

2013-01-01

Full Text Available Elad Moisseiev,1,3 Tzahi Sela,2 Liza Minkev,2 David Varssano1,31Department of Ophthalmology, Tel-Aviv Medical Center, Tel-Aviv, Israel; 2Care Vision, Tel Aviv, Israel; 3Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, IsraelPurpose: To evaluate the trends in corneal refractive procedure selection for the correction of myopia, focusing on the relative proportions of laser in situ keratomileusis (LASIK and surface ablation procedures.Methods: Only eyes that underwent LASIK or surface ablation for the correction of myopia between 2008–2011 were included in this retrospective study. Additional recorded parameters included patient age, preoperative manifest refraction, corneal thickness, and calculated residual corneal bed thickness. A risk score was given to each eye, based on these parameters, according to the Ectasia Risk Factor Score System (ERFSS, without the preoperative corneal topography.Results: This study included 16,163 eyes, of which 38.4% underwent LASIK and 61.6% underwent surface ablation. The risk score correlated with procedure selection, with LASIK being preferred in eyes with a score of 0 and surface ablation in eyes with a score of 2 or higher. When controlling for age, preoperative manifest refraction, corneal thickness, and all parameters, the relative proportion of surface ablation compared with LASIK was found to have grown significantly during the study period.Conclusions: Our results indicate that with time, surface ablation tended to be performed more often than LASIK for the correction of myopia in our cohort. Increased awareness of risk factors and preoperative risk assessment tools, such as the ERFSS, have shifted the current practice of refractive surgery from LASIK towards surface ablation despite the former's advantages, especially in cases in which the risk for ectasia is more than minimal (risk score 2 and higher.Keywords: surface ablation, LASIK, PRK, myopia correction, ectasia

Advanced surface ablation for presbyopia using the Nidek EC-5000 laser.

Science.gov (United States)

Cantú, Roberto; Rosales, Marco A; Tepichín, Eduardo; Curioca, Andrée; Montes, Victor; Bonilla, Julio

2004-01-01

To present 1 to 6-month follow-up results of laser in situ keratomileusis (LASIK) using multizone presbyopic advanced surface ablation (PASA) with a peripheral near zone. LASIK was performed on 28 eyes of 17 patients (10 men and 7 women; mean age 49.8 years with a range of 37 to 62 years). Eyes had primary or enhancement treatments with the Nidek EC-5000 excimer laser. Three techniques were used: 1) total transepithelial ablation, 2) surface ablation for far vision ametropia correction, and 3) concentric peripheral near zone presbyopia correction (technique developed by Dr. A. Telandro with a modified nomogram by Dr. R. Cantú for surface ablation). One surgeon (RC) performed all surgery. We present the preoperative and postoperative measurements for far and near uncorrected visual acuity, total high order aberrations, spherical aberration (Z-12), asphericity Q index, eccentricity corneal shape factor, and total coma and trefoil aberrations. Increases occurred in negative spherical aberration, negative asphericity index, and positive eccentricity corneal shape factor. Advanced surface ablation for presbyopia with a concentric peripheral near zone is a promising approach for surgical correction of presbyopia and potentially could be used with any advanced surface ablation procedure. Increases in negative spherical aberration and asphericity/ eccentricity indices seemed to increase the depth of focus of the eye, improving the near vision.

Development of locomotor activity of rat pups in figure-eight mazes.

Science.gov (United States)

Ruppert, P H; Dean, K F; Reiter, L W

1985-05-01

In a series of four experiments, social and experiential factors that influence the development of motor activity in rat pups were examined. Motor activity was monitored from postnatal Days 13 to 21 as photocell interruptions in figure-eight mazes and comparisons were made between pups maintained in a nest box containing a dam and siblings and allowed access to the maze for 23 hr/day, pups tested daily for 1 hr/day vs pups tested only on postnatal Days 15, 18, or 21, pups tested daily for either 5 min, 30 min, or 1 hr/day, and pups tested daily for 30 min/day either singly in a maze, paired with a littermate, or paired with an anesthetized pup of the same age. A monotonic increase in activity was seen for nest-box testing, minimal developmental change was seen for pups tested on only a single day or for pups tested with an anesthetized pup, whereas all other groups showed an inverted U-shaped profile of activity which was influenced by the duration of testing and/or the presence of a littermate. These data emphasize the relevance of environmental factors as determinants of preweaning behavior.

Impact of Tricuspid Regurgitation on the Success of Atrioventricular Node Ablation for Rate Control in Patients With Atrial Fibrillation: The Node Blast Study.

Science.gov (United States)

Reddy, Yeruva Madhu; Gunda, Sampath; Vallakati, Ajay; Kanmanthareddy, Arun; Pillarisetti, Jayasree; Atkins, Donita; Bommana, Sudharani; Emert, Martin P; Pimentel, Rhea; Dendi, Raghuveer; Berenbom, Loren D; Lakkireddy, Dhanunjaya

2015-09-15

Atrioventricular node (AVN) ablation is an effective treatment for symptomatic patients with atrial arrhythmias who are refractory to rhythm and rate control strategies where optimal ventricular rate control is desired. There are limited data on the predictors of failure of AVN ablation. Our objective was to identify the predictors of failure of AVN ablation. This is an observational single-center study of consecutive patients who underwent AVN ablation in a large academic center. Baseline characteristics, procedural variables, and outcomes of AVN ablation were collected. AVN "ablation failure" was defined as resumption of AVN conduction resulting in recurrence of either rapid ventricular response or suboptimal biventricular pacing. A total of 247 patients drug refractory AF who underwent AVN ablation at our center with a mean age of 71 ± 12 years with 46% being males were included. Ablation failure was seen in 11 (4.5%) patients. There were no statistical differences between patients with "ablation failure" versus "ablation success" in any of the baseline clinical variables. Patients with moderate-to-severe tricuspid regurgitation (TR) were much more likely to have ablation failure than those with ablation success (8 [73%] vs 65 [27%]; p = 0.003). All 11 patients with ablation failure had a successful redo procedure, 9 with right and 2 with the left sided approach. On multivariate analysis, presence of moderate-to-severe TR was found to be the only predictor of failure of AVN ablation (odds ratio 9.1, confidence interval 1.99 to 42.22, p = 0.004). In conclusion, moderate-to-severe TR is a strong and independent predictor of failure of AVN ablation. Copyright © 2015 Elsevier Inc. All rights reserved.

Radiofrequency ablation of liver metastases; Radiofrequenzablation von Lebermetastasen

Energy Technology Data Exchange (ETDEWEB)

Pereira, P.L.; Clasen, S.; Schmidt, D.; Wiskirchen, J.; Tepe, G.; Claussen, C.D. [Abt. fuer Radiologische Diagnostik, Eberhard-Karls-Univ. Tuebingen (Germany); Boss, A. [Abt. fuer Radiologische Diagnostik, Eberhard-Karls-Univ. Tuebingen (Germany); Sektion fuer Experimentelle Radiologie der Abt. fuer Radiologische Diagnostik, Eberhard-Karls-Univ. Tuebingen (Germany); Gouttefangeas, C. [Abt. Immunologie des Inst. fuer Zellbiologie, Eberhard-Karls-Univ. Tuebingen (Germany); Burkart, C. [Zentrum fuer gastroenterologische Onkologie der Medizinischen Klinik, Eberhard-Karls-Univ. Tuebingen (Germany)

2004-04-01

The liver is the second only to lymph nodes as the most common site of metastatic disease irrespective of the primary tumor. Up to 50% of all patients with malignant diseases will develop liver metastases with a significant morbidity and mortality. Although the surgical resection leads to an improvement of the survival time, only approximately 20% of the patients are eligible for surgical intervention. Radiofrequency (RF) ablation represents one of the most important alternatives as well as complementary methods for the therapy of liver metastases. RF ablation can lead in a selected patient group to a palliation or to an increased life expectancy. RF ablation appears either safer (vs. cryotherapy) or easier (vs. laser) or more effective (percutaneous ethanol instillation [PEI]), transarterial chemoembolisation [TACE] in comparison with other minimal invasive procedures. RF ablation can be performed percutaneously, laparoscopically or intraoperatively and may be combined with chemotherapy as well as with surgical resection. Permanent technical improvements of RF systems, a better understanding of the underlying electrophysiological principles and an interdisciplinary approach will lead to a prognosis improvement in patients with liver metastases. (orig.) [German] Die Leber ist unabhaengig vom Primaertumor nach den Lymphknoten die zweithaeufigste Lokalisation von Metastasen. Bis zu 50% aller Patienten mit malignen Erkrankungen werden im Verlauf ihrer Erkrankung Lebermetastasen entwickeln, die mit einer signifikanten Morbiditaet und Mortalitaet verbunden sind. Obwohl die chirurgische Resektion zu einer verlaengerten Ueberlebenszeit fuehrt, sind nur ca. 20% der Patienten fuer einen chirurgischen Eingriff geeignet. Die Radiofrequenz-(RF-)Ablation stellt derzeit eine der effektivsten Alternativen und komplementaeren Methoden bei der Therapie von Lebermetastasen dar. In einem selektierten Patientengut fuehrt die RF-Ablation ueber den palliativen Einsatz hinaus zu einer

Effect of ablatant composition on the ablation of a fuelling pellet

International Nuclear Information System (INIS)

Chang, C.T.; Thomsen, K.; Piret, S.

1988-01-01

The single species neutral-shielding model for the ablation of a hydrogenic pellet is extended by considering the ablatant as a mixture of four species: molecular and atomic hydrogen, protons and electrons. Compared with the results of the frozen flow, (i.e. the single species molecular hydrogen gas model), results of the analysis showed that the presence of dissociation and ionization effects caused a marked difference of the ablatant state. The attenuations of the incoming electron energy and energy flux, however, are very much similar irrespective of whether the ablated flow is in a frozen or an equilibrium state. The scaling law of the pellet ablation rate with respect to the plasma state of Te, ne and the pellet radius remains the same; the ablation rate is reduced by approximately 15%. To examine the possible existence of a spherical shell around the pellet where most of the incoming electron energy is absorbed, acodmparison is made between the local electron collisional mean free path and the electron Larmor radius. A critical field at the ionization radius is evaluated. An effective spherical energyabsorbing region exists when the local field strength is below the critical value. For a plasma state of low Te and ne, (where the ablatant is hardly ionized), and for one near the thermonuclear condition (where a highly dense ablatant exists near the pellet), the effective energy absorption region is nearly spherical. 20 refs. (author)

On the tenth value distance of the photon field along the maze of high-energy linear accelerator vaults.

Science.gov (United States)

Han, Zhaohui; Chin, Lee M

2018-03-01

There is a wide range in the reported photon tenth value distance (TVD) in the maze of high-energy linear accelerator vaults. In order to gain insight into the appropriate use of the TVD value during door design, we performed measurements of the photon dose in the maze of four vaults. In addition, our study represents the first to describe a scenario where an inner borated polyethylene (BPE) door for neutron shielding is installed in the maze downstream to Point A, the point on the maze centerline that is just visible from the isocenter. The measurements were made along the maze centerline at 1 m above the floor. In all cases, the accelerator operated at a nominal energy of 15 MV. Of the four vaults, three were equipped with an inner BPE door at a distance of 1.0-2.1 m downstream to Point A. The door was made of 10.16 cm (4″) BPE sandwiched between two 0.635 cm (1/4″) steel face plates. The photon dose in the maze without a BPE door decreases exponentially with a characteristic TVD of 6 m beyond a distance of 2.5 m from Point A. The presence of a BPE door in an identical vault not only reduces the photon intensity in the maze by about an order of magnitude, but also softens the energy spectrum with a shortened TVD of 4.7 m, significantly lessening the shielding burden at the outer maze entrance. In contrast to the common use of Point A as the reference point to specify distance, the photon dose in the maze with a BPE door located downstream to Point A can be satisfactorily described as exponential functions of the distance measured from the door, which shows good consistency among the three vaults of different room parameters. © 2018 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

Conventional versus 3-D Echocardiography to Predict Arrhythmia Recurrence After Atrial Fibrillation Ablation.

Science.gov (United States)

Bossard, Matthias; Knecht, Sven; Aeschbacher, Stefanie; Buechel, Ronny R; Hochgruber, Thomas; Zimmermann, Andreas J; Kessel-Schaefer, Arnheid; Stephan, Frank-Peter; Völlmin, Gian; Pradella, Maurice; Sticherling, Christian; Osswald, Stefan; Kaufmann, Beat A; Conen, David; Kühne, Michael

2017-06-01

Arrhythmia recurrence after atrial fibrillation (AF) ablation remains high and requires repeat interventions in a substantial number of patients. We assessed the value of conventional and 3-D echocardiography to predict AF recurrence. Consecutive patients undergoing AF ablation by means of pulmonary vein isolation were included in a prospective registry. Echocardiograms were obtained prior to the ablation procedure, and analyzed offline in a standardized manner, including 3-D left atrial (LA) volumetry and determination of LA function and sphericity. The primary endpoint, AF recurrence (>30 seconds) between 3 to 12 months after AF ablation, was independently adjudicated. We included 276 patients (73% male, mean age 59.9 ± 9.9 years). Paroxysmal and persistent AF were present in 178 (64%) and 98 (36%) patients, respectively. Mean left ventricular ejection fraction and indexed LA volume in 3-D (LAVI) were 52 ± 12% and 42 ± 13 mL/m 2 , respectively. AF recurrence was observed in 110 (40%) patients after a single procedure. Median (interquartile range) time to AF recurrence was 123 (92; 236) days. In multivariable Cox regression models, the only predictors for AF recurrence were the minimal, maximal, and indexed 3-D LA volumes, P = 0.024, P = 0.016, and P = 0.014, respectively. Quartile specific analysis of 3-D LAVI showed an HR of 1.885 (95%CI 1.066-3.334; P for trend = 0.015) for the highest compared to the lowest quartile. Our results show the important role of LA volume for the long-term freedom from arrhythmia after AF ablation. These data also highlight the potential of 3-D echocardiography in this context and may facilitate patient selection for AF ablation. © 2017 Wiley Periodicals, Inc.

Frequency and Risk Factors of Various Complications After Computed Tomography-Guided Radiofrequency Ablation of Lung Tumors

International Nuclear Information System (INIS)

Okuma, Tomohisa; Matsuoka, Toshiyuki; Yamamoto, Akira; Oyama, Yoshimasa; Toyoshima, Masami; Nakamura, Kenji; Inoue, Yuichi

2008-01-01

Objective. To retrospectively determine the frequency and risk factors of various side effects and complications after percutaneous computed tomography-guided radiofrequency (RF) ablation of lung tumors. Methods. We reviewed and analyzed records of 112 treatment sessions in 57 of our patients (45 men and 12 women) with unresectable lung tumors treated by ablation. Risk factors, including sex, age, tumor diameter, tumor location, history of surgery, presence of pulmonary emphysema, electrode gauge, array diameter, patient position, maximum power output, ablation time, and minimum impedance during ablation, were analyzed using univariate and multivariate analyses. Results. Total rates of side effects and minor and major complications occurred in 17%, 50%, and 8% of treatment sessions, respectively. Side effects, including pain during ablation (46% of sessions) and pleural effusion (13% of sessions), occurred with RF ablation. Minor complications, including pneumothorax not requiring chest tube drainage (30% of sessions), subcutaneous emphysema (16% of sessions), and hemoptysis (9% of sessions) also occurred after the procedure. Regarding major complications, three patients developed fever >38.5 deg. C; three patients developed abscesses; two patients developed pneumothorax requiring chest tube insertion; and one patient had air embolism and was discharged without neurologic deficit. Univariate and multivariate analyses suggested that a lesion located ≤1 cm of the chest wall was significantly related to pain (p < 0.01, hazard index 5.76). Risk factors for pneumothorax increased significantly with previous pulmonary surgery (p < 0.05, hazard index 6.1) and presence of emphysema (p <0.01, hazard index 13.6). Conclusion. The total complication rate for all treatment sessions was 58%, and 25% of patients did not have any complications after RF ablation. Although major complications can occur, RF ablation of lung tumors can be considered a safe and minimally invasive

Treatment of Osteoid Osteomas Using a Navigational Bipolar Radiofrequency Ablation System

Energy Technology Data Exchange (ETDEWEB)

Wallace, Adam N., E-mail: wallacea@mir.wustl.edu; Tomasian, Anderanik, E-mail: tomasiana@mir.wustl.edu [Washington University School of Medicine, Mallinckrodt Institute of Radiology (United States); Chang, Randy O., E-mail: changr@wusm.wustl.edu [Washington University School of Medicine (United States); Jennings, Jack W., E-mail: jenningsj@mir.wustl.edu [Washington University School of Medicine, Mallinckrodt Institute of Radiology (United States)

2016-05-15

BackgroundPercutaneous CT-guided radiofrequency ablation is a safe and effective minimally invasive treatment for osteoid osteomas. This technical case series describes the use of a recently introduced ablation system with a probe that can be curved in multiple directions, embedded thermocouples for real-time monitoring of the ablation volume, and a bipolar design that obviates the need for a grounding pad.MethodsMedical records of all patients who underwent radiofrequency ablation of an osteoid osteoma with the STAR Tumor Ablation System (DFINE; San Jose, CA) were reviewed. The location of each osteoid osteoma, nidus volume, and procedural details were recorded. Treatment efficacy and long-term complications were assessed at clinical follow-up.ResultsDuring the study period, 18 osteoid osteomas were radiofrequency ablated with the multidirectional bipolar system. Lesion locations included the femur (50 %; 9/18), tibia (22 %; 4/18), cervical spine (11 %; 2/18), calcaneus (5.5 %; 1/18), iliac bone (5.5 %; 1/18), and fibula (5.5 %; 1/18). The median nidus volume of these cases was 0.33 mL (range 0.12–2.0 mL). All tumors were accessed via a single osseous channel. Median cumulative ablation time was 5 min and 0 s (range 1 min and 32 s–8 min and 50 s). All patients with clinical follow-up reported complete symptom resolution. No complications occurred.ConclusionSafe and effective CT-guided radiofrequency ablation of osteoid osteomas can be performed in a variety of locations using a multidirectional bipolar system.

Treatment of Osteoid Osteomas Using a Navigational Bipolar Radiofrequency Ablation System

International Nuclear Information System (INIS)

Wallace, Adam N.; Tomasian, Anderanik; Chang, Randy O.; Jennings, Jack W.

2016-01-01

BackgroundPercutaneous CT-guided radiofrequency ablation is a safe and effective minimally invasive treatment for osteoid osteomas. This technical case series describes the use of a recently introduced ablation system with a probe that can be curved in multiple directions, embedded thermocouples for real-time monitoring of the ablation volume, and a bipolar design that obviates the need for a grounding pad.MethodsMedical records of all patients who underwent radiofrequency ablation of an osteoid osteoma with the STAR Tumor Ablation System (DFINE; San Jose, CA) were reviewed. The location of each osteoid osteoma, nidus volume, and procedural details were recorded. Treatment efficacy and long-term complications were assessed at clinical follow-up.ResultsDuring the study period, 18 osteoid osteomas were radiofrequency ablated with the multidirectional bipolar system. Lesion locations included the femur (50 %; 9/18), tibia (22 %; 4/18), cervical spine (11 %; 2/18), calcaneus (5.5 %; 1/18), iliac bone (5.5 %; 1/18), and fibula (5.5 %; 1/18). The median nidus volume of these cases was 0.33 mL (range 0.12–2.0 mL). All tumors were accessed via a single osseous channel. Median cumulative ablation time was 5 min and 0 s (range 1 min and 32 s–8 min and 50 s). All patients with clinical follow-up reported complete symptom resolution. No complications occurred.ConclusionSafe and effective CT-guided radiofrequency ablation of osteoid osteomas can be performed in a variety of locations using a multidirectional bipolar system.

Factors related to postoperative pain among patients who underwent radiofrequency ablation of hepatocellular carcinoma

International Nuclear Information System (INIS)

Hsieh, Y.-C.; Yap, Y.-S.; Hung, C.-H.; Chen, C.-H.; Lu, S.-N.; Wang, J.-H.

2013-01-01

Aim: To evaluate the incidence and associated factors of postoperative intense pain and haemodynamic changes during radiofrequency ablation of hepatocellular carcinoma. Materials and methods: A total of 123 consecutive hepatocellular carcinoma patients who underwent radiofrequency ablation were prospectively recruited. Patient factors, tumour characteristics, procedural factors, intraoperative haemodynamic changes, complications, postoperative events, laboratory values before and after ablation, and postoperative pain were evaluated. Postoperative pain was scored using a visual analogue scale after the procedure. Results: The mean age of the patients was 65.6 ± 9.6 years. In multiple logistic regression analysis, patients who underwent general anaesthesia [odds ratio (95% CI): 2.68 (1.23–5.81); p = 0.013] and had more postoperative nausea and vomiting episodes [3.10 (1.11–8.63); p = 0.036] were associated with intense pain. These findings remain robust after propensity score matching. For mean difference values between before and after RFA, higher in change in aspartate transaminase (p = 0.026), alanine transaminase (p = 0.016) and white blood cell count (p = 0.015), and lower in change in haemoglobin (p = 0.009) were also correlated with intense pain. There was no significant difference in haemodynamic changes between the general anaesthesia and local anaesthesia group during ablation. Conclusion: General anaesthesia, postoperative nausea and vomiting, and laboratory factors were associated with postoperative intense pain in patients who underwent radiofrequency ablation. Counselling and modification of analgesics should be considered in patients with related factors for intense pain

Neural correlates of olfactory and visual memory performance in 3D-simulated mazes after intranasal insulin application.

Science.gov (United States)

Brünner, Yvonne F; Rodriguez-Raecke, Rea; Mutic, Smiljana; Benedict, Christian; Freiherr, Jessica

2016-10-01

This fMRI study intended to establish 3D-simulated mazes with olfactory and visual cues and examine the effect of intranasally applied insulin on memory performance in healthy subjects. The effect of insulin on hippocampus-dependent brain activation was explored using a double-blind and placebo-controlled design. Following intranasal administration of either insulin (40IU) or placebo, 16 male subjects participated in two experimental MRI sessions with olfactory and visual mazes. Each maze included two separate runs. The first was an encoding maze during which subjects learned eight olfactory or eight visual cues at different target locations. The second was a recall maze during which subjects were asked to remember the target cues at spatial locations. For eleven included subjects in the fMRI analysis we were able to validate brain activation for odor perception and visuospatial tasks. However, we did not observe an enhancement of declarative memory performance in our behavioral data or hippocampal activity in response to insulin application in the fMRI analysis. It is therefore possible that intranasal insulin application is sensitive to the methodological variations e.g. timing of task execution and dose of application. Findings from this study suggest that our method of 3D-simulated mazes is feasible for studying neural correlates of olfactory and visual memory performance. Copyright © 2016 Elsevier Inc. All rights reserved.

Single-shot and single-spot measurement of laser ablation threshold for carbon nanotubes

OpenAIRE

Lednev, Vasily N.; Pershin, Sergey M.; Obraztsova, Elena D.; Kudryashov, Sergey I.; Bunkin, Alexey F.

2013-01-01

A simple and convenient procedure for single-shot, single-spot ablation threshold measurement has been developed. It is based on the employment of cylindrical lens to obtain elliptical Gaussian laser spot. The ablated spot chords which are parallel to the minor axis were measured across the spot major axis which is proportional to the fluence cross-section thus providing wide range dependence of damaged spot size versus fluence in one spot measurement. For both conventional and new-developed ...

Phrenic nerve injury after radiofrequency ablation of lung tumors: retrospective evaluation of the incidence and risk factors.

Science.gov (United States)

Matsui, Yusuke; Hiraki, Takao; Gobara, Hideo; Uka, Mayu; Masaoka, Yoshihisa; Tada, Akihiro; Toyooka, Shinichi; Mitsuhashi, Toshiharu; Mimura, Hidefumi; Kanazawa, Susumu

2012-06-01

To retrospectively investigate the incidence of and risk factors for phrenic nerve injury after radiofrequency (RF) ablation of lung tumors. The study included 814 RF ablation procedures of lung tumors. To evaluate the development of phrenic nerve injury, chest radiographs obtained before and after the procedure were examined. Phrenic nerve injury was assumed to have developed if the diaphragmatic level was elevated after the procedure. To identify risk factors for phrenic nerve injury, multiple variables were compared between cases of phrenic nerve injury and randomly selected controls by using univariate analyses. Multivariate analysis was then performed to identify independent risk factors. Evaluation of phrenic nerve injury from chest radiographs was possible after 786 procedures. Evidence of phrenic nerve injury developed after 10 cases (1.3%). Univariate analysis revealed that larger tumor size (≥ 20 mm; P = .014), proximity of the phrenic nerve to the tumor (phrenic nerve injury. Multivariate analysis demonstrated that the proximity of the phrenic nerve to the tumor (phrenic nerve injury after RF ablation was 1.3%. The proximity of the phrenic nerve to the tumor was an independent risk factor for phrenic nerve injury. Copyright © 2012 SIR. Published by Elsevier Inc. All rights reserved.

A prospective development study of software-guided radio-frequency ablation of primary and secondary liver tumors: Clinical intervention modelling, planning and proof for ablation cancer treatment (ClinicIMPPACT).

Science.gov (United States)

Reinhardt, Martin; Brandmaier, Philipp; Seider, Daniel; Kolesnik, Marina; Jenniskens, Sjoerd; Sequeiros, Roberto Blanco; Eibisberger, Martin; Voglreiter, Philip; Flanagan, Ronan; Mariappan, Panchatcharam; Busse, Harald; Moche, Michael

2017-12-01

Radio-frequency ablation (RFA) is a promising minimal-invasive treatment option for early liver cancer, however monitoring or predicting the size of the resulting tissue necrosis during the RFA-procedure is a challenging task, potentially resulting in a significant rate of under- or over treatments. Currently there is no reliable lesion size prediction method commercially available. ClinicIMPPACT is designed as multicenter-, prospective-, non-randomized clinical trial to evaluate the accuracy and efficiency of innovative planning and simulation software. 60 patients with early liver cancer will be included at four European clinical institutions and treated with the same RFA system. The preinterventional imaging datasets will be used for computational planning of the RFA treatment. All ablations will be simulated simultaneously to the actual RFA procedure, using the software environment developed in this project. The primary outcome measure is the comparison of the simulated ablation zones with the true lesions shown in follow-up imaging after one month, to assess accuracy of the lesion prediction. This unique multicenter clinical trial aims at the clinical integration of a dedicated software solution to accurately predict lesion size and shape after radiofrequency ablation of liver tumors. Accelerated and optimized workflow integration, and real-time intraoperative image processing, as well as inclusion of patient specific information, e.g. organ perfusion and registration of the real RFA needle position might make the introduced software a powerful tool for interventional radiologists to optimize patient outcomes.

Maze solving algorithm and its programs using Z-80 assembler language for a robot

Energy Technology Data Exchange (ETDEWEB)

Takeno, J; Mukaidono, M

1982-01-01

In the first part the formation of a maze problem is introduced and the outline of this algorithm to solve a maze is explained in the second part. The third part describes the detail of this program, and the final part shows the program which has been developed using Z-80 assembler language. This program has portability for other robots using Z-80 microprocessors. 7 references.

MR-Guided Laser Ablation of Osteoid Osteoma in an Open High-Field System (1.0 T)

International Nuclear Information System (INIS)

Streitparth, F.; Gebauer, B.; Melcher, I.; Schaser, K.; Philipp, C.; Rump, J.; Hamm, B.; Teichgraeber, U.

2009-01-01

Computed tomography is the standard imaging modality to minimize the extent of surgical or ablative treatment in osteoid osteomas. In the last 15 years, since a description of thermal ablation of osteoid osteomas was first published, this technique has become a treatment of choice for this tumor. We report the case of a 20-year-old man with an osteoid osteoma treated with laser ablation in an open high-field magnetic resonance imaging scanner (1.0 T). The tumor, located in the right fibula, was safely and effectively ablated under online monitoring. We describe the steps of this interventional procedure and discuss related innovative guidance and monitoring features and potential benefits compared with computed tomographic guidance.

Resultados da ablação cirúrgica por radiofreqüência da fibrilação atrial crônica Results of the intraoperative radiofrequency ablation of chronic atrial fibrillation

Directory of Open Access Journals (Sweden)

Carlos Alberto Cordeiro de Abreu Filho

2004-09-01

Full Text Available OBJETIVO: A operação de "Cox-Maze III" apresenta alta efetividade para o tratamento da fibrilação atrial (FA crônica, porém, devido a sua alta complexidade, não é amplamente utilizada. Novas alternativas, que envolvem o uso de fontes de energia, como a radiofreqüência, para criação de lesões transmurais, que substituem as linhas de secção e sutura da técnica de Cox, foram desenvolvidas visando simplificar o procedimento. O objetivo deste estudo é avaliar os resultados do emprego da radiofreqüência intra-operatória para tratamento da FA crônica em pacientes com cardiopatias associadas com indicação de tratamento cirúrgico. MÉTODO: Entre fevereiro de 2002 e março de 2003, 35 pacientes consecutivos portadores de FA crônica foram submetidos à ablação com radiofreqüência intra-operatória, associada a outros procedimentos cirúrgicos. A idade variou de 16 a 69 anos (média = 55,4 anos, sendo 23 (65,7% pacientes do sexo feminino. RESULTADOS: A ablação foi associada ao tratamento cirúrgico da valva mitral em 29 (82,9% pacientes e à atriosseptoplastia em seis (17,1% pacientes. A mortalidade hospitalar foi de 2,8%; vinte e seis (76,4% pacientes apresentavam-se em ritmo sinusal no momento da alta hospitalar. Após seguimento médio de 11,7 ± 2,8 meses, a sobrevida foi de 94,2% e 24 (72,7% pacientes apresentavam-se em ritmo sinusal. CONCLUSÃO: A ablação por radiofreqüência intra-operatória demonstrou ser uma técnica segura e eficiente para o tratamento da FA crônica, apresentando índices satisfatórios de reversão para o ritmo sinusal em médio prazo.OBJECTIVE: The "Cox-Maze III" operation is very effective in the treatment of chronic atrial fibrillation, but many surgeons do not use this technique because of its high complexity. In order to simplify the procedure, new alternatives that involve the use of different energy sources, such as radiofrequency, to create transmural lesions that substitute the atrial

Laser ablation principles and applications

CERN Document Server

1994-01-01

Laser Ablation provides a broad picture of the current understanding of laser ablation and its many applications, from the views of key contributors to the field. Discussed are in detail the electronic processes in laser ablation of semiconductors and insulators, the post-ionization of laser-desorbed biomolecules, Fourier-transform mass spectroscopy, the interaction of laser radiation with organic polymers, laser ablation and optical surface damage, laser desorption/ablation with laser detection, and laser ablation of superconducting thin films.

Prediction and prognosis of ventricular tachycardia recurrence after catheter ablation with remote magnetic navigation for electrical storm in patients with ischemic cardiomyopathy.

Science.gov (United States)

Jin, Qi; Jacobsen, Peter Karl; Pehrson, Steen; Chen, Xu

2017-11-01

Ventricular tachycardia (VT) recurrence after catheter ablation for electrical storm is commonly seen in patients with ischemic cardiomyopathy (ICM). We hypothesized that VT recurrence can be predicted and be related to the all-cause death after VT storm ablation guided by remote magnetic navigation (RMN) in patients with ICM. A total of 54 ICM patients (87% male; mean age, 65 ± 7.1 years) presenting with VT storm undergoing acute ablation using RMN were enrolled. Acute complete ablation success was defined as noninducibility of any sustained monomorphic VT at the end of the procedure. Early VT recurrence was defined as the occurrence of sustained VT within 1 month after the first ablation. After a mean follow-up of 17.1 months, 27 patients (50%) had freedom from VT recurrence. Sustained VT recurred in 12 patients (22%) within 1 month following the first ablation. In univariate analysis, VT recurrence was associated with incomplete procedural success (hazard ratio [HR]: 6.25, 95% confidence interval [CI]: 1.20-32.47, P = 0.029), lack of amiodarone usage before ablation (HR: 4.71, 95% CI: 1.12-19.7, P = 0.034), and a longer procedural time (HR: 1.023, 95% CI: 1.00-1.05, P = 0.05). The mortality of patients with early VT recurrence was higher than that of patients without recurrence (P storm guided by RMN is the strongest predictor of VT recurrence. ICM patients who have early recurrences after VT storm ablation are at high risk of all-cause death. © 2017 Wiley Periodicals, Inc.

Percutaneous Irreversible Electroporation Lung Ablation: Preliminary Results in a Porcine Model

International Nuclear Information System (INIS)

Deodhar, Ajita; Monette, Sébastien; Single, Gordon W.; Hamilton, William C.; Thornton, Raymond H.; Sofocleous, Constantinos T.; Maybody, Majid; Solomon, Stephen B.

2011-01-01

Objective: Irreversible electroporation (IRE) uses direct electrical pulses to create permanent “pores” in cell membranes to cause cell death. In contrast to conventional modalities, IRE has a nonthermal mechanism of action. Our objective was to study the histopathological and imaging features of IRE in normal swine lung. Materials and Methods: Eleven female swine were studied for hyperacute (8 h), acute (24 h), subacute (96 h), and chronic (3 week) effects of IRE ablation in lung. Paired unipolar IRE applicators were placed under computed tomography (CT) guidance. Some applicators were deliberately positioned near bronchovascular structures. IRE pulse delivery was synchronized with the cardiac rhythm only when ablation was performed within 2 cm of the heart. Contrast-enhanced CT scan was performed immediately before and after IRE and at 1 and 3 weeks after IRE ablation. Representative tissue was stained with hematoxylin and eosin for histopathology. Results: Twenty-five ablations were created: ten hyperacute, four acute, and three subacute ablations showed alveolar edema and necrosis with necrosis of bronchial, bronchiolar, and vascular epithelium. Bronchovascular architecture was maintained. Chronic ablations showed bronchiolitis obliterans and alveolar interstitial fibrosis. Immediate post-procedure CT images showed linear or patchy density along the applicator tract. At 1 week, there was consolidation that resolved partially or completely by 3 weeks. Pneumothorax requiring chest tube developed in two animals; no significant cardiac arrhythmias were noted. Conclusion: Our preliminary porcine study demonstrates the nonthermal and extracellular matrix sparing mechanism of action of IRE. IRE is a potential alternative to thermal ablative modalities.

Little and often? Maintaining continued performance in an automated T-maze for mice.

Science.gov (United States)

Gaskill, Brianna N; Lucas, Jeffrey R; Pajor, Edmond A; Garner, Joseph P

2011-02-01

Operant and maze tasks in mice are limited by the small number of trials possible in a session before mice lose motivation. We hypothesized that by manipulating reward size and session length, motivation, and hence performance, would be maintained in an automated T-maze. We predicted that larger rewards and shorter sessions would improve acquisition; and smaller rewards and shorter sessions would maintain higher and less variable performance. Eighteen C57BL/6J mice (9 per sex) acquired (criterion 8/10 correct) and performed a spatial discrimination, with one of 3 reward sizes (.02, .04, or .08 g) and one of 3 session schedules (15, 30, or 45 min sessions). Each mouse had a total of 360 min of access to the maze per night, for two nights, and averaged 190 trials. Analysis used split-plot GLM with contrasts testing for linear effects. Acquisition of the discrimination was unaffected by reward size or session length/interval. After-criterion average performance improved as reward size decreased. After-criterion variability in performance was also affected. Variability increased as reward size increased. Session length/interval did not affect any outcome. We conclude that an automated maze, with suitable reward sizes, can sustain performance with low variability, at 5-10 times faster than traditional methods. Copyright © 2011 Elsevier B.V. All rights reserved.

Impact of esophageal temperature monitoring guided atrial fibrillation ablation on preventing asymptomatic excessive transmural injury

Science.gov (United States)

Kiuchi, Kunihiko; Okajima, Katsunori; Shimane, Akira; Kanda, Gaku; Yokoi, Kiminobu; Teranishi, Jin; Aoki, Kousuke; Chimura, Misato; Toba, Takayoshi; Oishi, Shogo; Sawada, Takahiro; Tsukishiro, Yasue; Onishi, Tetsuari; Kobayashi, Seiichi; Taniguchi, Yasuyo; Yamada, Shinichiro; Yasaka, Yoshinori; Kawai, Hiroya; Yoshida, Akihiro; Fukuzawa, Koji; Itoh, Mitsuaki; Imamura, Kimitake; Fujiwara, Ryudo; Suzuki, Atsushi; Nakanishi, Tomoyuki; Yamashita, Soichiro; Hirata, Ken-ichi; Tada, Hiroshi; Yamasaki, Hiro; Naruse, Yoshihisa; Igarashi, Miyako; Aonuma, Kazutaka

2015-01-01

Background Even with the use of a reduced energy setting (20–25 W), excessive transmural injury (ETI) following catheter ablation of atrial fibrillation (AF) is reported to develop in 10% of patients. However, the incidence of ETI depends on the pulmonary vein isolation (PVI) method and its esophageal temperature monitor setting. Data comparing the incidence of ETI following AF ablation with and without esophageal temperature monitoring (ETM) are still lacking. Methods This study was comprised of 160 patients with AF (54% paroxysmal, mean: 24.0±2.9 kg/m2). Eighty patients underwent ablation accompanied by ETM. The primary endpoint was defined as the occurrence of ETI assessed by endoscopy within 5 d after the AF ablation. The secondary endpoint was defined as AF recurrence after a single procedure. If the esophageal temperature probe registered >39 °C, the radiofrequency (RF) application was stopped immediately. RF applications could be performed in a point-by-point manner for a maximum of 20 s and 20 W. ETI was defined as any injury that resulted from AF ablation, including esophageal injury or periesophageal nerve injury (peri-ENI). Results The incidence of esophageal injury was significantly lower in patients whose AF ablation included ETM compared with patients without ETM (0 [0%] vs. 6 [7.5%], p=0.028), but not the incidence of peri-ENI (2 [2.5%] vs. 3 [3.8%], p=1.0). AF recurrence 12 months after the procedure was similar between the groups (20 [25%] in the ETM group vs. 19 [24%] in the non-ETM group, p=1.00). Conclusions Catheter ablation using ETM may reduce the incidence of esophageal injury without increasing the incidence of AF recurrence but not the incidence of peri-ENI. PMID:26949429

Microwave Ablation Compared with Radiofrequency Ablation for Breast Tissue in an Ex Vivo Bovine Udder Model

International Nuclear Information System (INIS)

Tanaka, Toshihiro; Westphal, Saskia; Isfort, Peter; Braunschweig, Till; Penzkofer, Tobias; Bruners, Philipp; Kichikawa, Kimihiko; Schmitz-Rode, Thomas; Mahnken, Andreas H.

2012-01-01

Purpose: To compare the effectiveness of microwave (MW) ablation with radiofrequency (RF) ablation for treating breast tissue in a nonperfused ex vivo model of healthy bovine udder tissue. Materials and Methods: MW ablations were performed at power outputs of 25W, 35W, and 45W using a 915-MHz frequency generator and a 2-cm active tip antenna. RF ablations were performed with a bipolar RF system with 2- and 3-cm active tip electrodes. Tissue temperatures were continuously monitored during ablation. Results: The mean short-axis diameters of the coagulation zones were 1.34 ± 0.14, 1.45 ± 0.13, and 1.74 ± 0.11 cm for MW ablation at outputs of 25W, 35W, and 45W. For RF ablation, the corresponding values were 1.16 ± 0.09 and 1.26 ± 0.14 cm with electrodes having 2- and 3-cm active tips, respectively. The mean coagulation volumes were 2.27 ± 0.65, 2.85 ± 0.72, and 4.45 ± 0.47 cm 3 for MW ablation at outputs of 25W, 35W, and 45W and 1.18 ± 0.30 and 2.29 ± 0.55 cm 3 got RF ablation with 2- and 3-cm electrodes, respectively. MW ablations at 35W and 45W achieved significantly longer short-axis diameters than RF ablations (P < 0.05). The highest tissue temperature was achieved with MW ablation at 45W (P < 0.05). On histological examination, the extent of the ablation zone in MW ablations was less affected by tissue heterogeneity than that in RF ablations. Conclusion: MW ablation appears to be advantageous with respect to the volume of ablation and the shape of the margin of necrosis compared with RF ablation in an ex vivo bovine udder.

Image and pathological changes after microwave ablation of breast cancer: A pilot study

Energy Technology Data Exchange (ETDEWEB)

Zhou, Wenbin [Department of Breast Surgery, The First Affiliated Hospital, Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029 (China); Jiang, Yanni [Department of Radiology, The First Affiliated Hospital, Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029 (China); Chen, Lin; Ling, Lijun; Liang, Mengdi; Pan, Hong [Department of Breast Surgery, The First Affiliated Hospital, Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029 (China); Wang, Siqi [Department of Radiology, The First Affiliated Hospital, Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029 (China); Ding, Qiang [Department of Breast Surgery, The First Affiliated Hospital, Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029 (China); Liu, Xiaoan, E-mail: liuxiaoan@126.com [Department of Breast Surgery, The First Affiliated Hospital, Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029 (China); Wang, Shui, E-mail: ws0801@hotmail.com [Department of Breast Surgery, The First Affiliated Hospital, Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029 (China)

2014-10-15

Highlights: • We report successful experience of MWA in breast cancer under local anesthesia. • We report MR imaging evaluation of microwave ablation zone in breast cancer. • Pathological changes after microwave ablation in breast cancer was reported. • 2 min MWA caused an ablation zone with three diameters > 2 cm in breast cancer. - Abstract: Purpose: To prospectively assess MR imaging evaluation of the ablation zone and pathological changes after microwave ablation (MWA) in breast cancer. Materials and methods: Twelve enrolled patients, diagnosed with non-operable locally advanced breast cancer (LABC), were treated by MWA and then neoadjuvant chemotherapy, followed by surgery. MR imaging was applied to evaluate the effect of MWA. Hematoxylin-eosin (HE) staining and transmission electron microscopy (TEM) were applied to analyze the ablated area. Results: All MWA procedures were performed successfully under local anesthesia. For a mean duration of 2.15 min, the mean largest, middle and smallest diameters in the ablated zone 24-h post-ablation in MR imaging were 2.98 cm ± 0.53, 2.51 cm ± 0.41 and 2.23 cm ± 0.41, respectively. The general shape of the ablation zone was close to a sphere. The ablated area became gradually smaller in MR imaging. No adverse effects related to MWA were noted in all 12 patients during and after MWA. HE staining could confirm the effect about 3 months after MWA, which was confirmed by TEM. Conclusions: 2 min MWA can cause an ablation zone with three diameters larger than 2 cm in breast cancer, which may be suitable for the local treatment of breast cancer up to 2 cm in largest diameter. However, the long-term effect of MWA in the treatment of small breast cancer should be determined in the future.

CT-guided radiofrequency ablation of spinal osteoid osteomas with concomitant perineural and epidural irrigation for neuroprotection

International Nuclear Information System (INIS)

Klass, Darren; Marshall, Tom; Toms, Andoni

2009-01-01

Here we report our experience of a neuroprotective adaptation of the technique of CT-guided radiofrequency (RF) ablation of spinal osteoid osteomas. Over 9 years seven patients underwent eight CT-guided RF treatments for osteoid osteoma. CT-guided RF ablation was performed with general anaesthesia. The lesion was heated to 90 C for 2 min for two cycles by using a Cosman SMK TC-10 RF electrode. This was preceded by a bolus of room temperature sterile water (10 ml) injected through a 26G curved spinal needle into the exit foramen and adjacent epidural space for neuroprotection. The age of the patient, sex, lesion location, biopsy results and complications were recorded. All the biopsies (n = 7) demonstrated histological features of osteoid osteoma. All the procedures were technically successful. Clinical success was assessed up to 3 years post procedure. There was an 85% clinical success rate (6 of the 7 patients), with recurrence of a lesion at 6 months, necessitating a repeat procedure (successful). CT-guided percutaneous RF ablation of spinal osteoid osteoma preceded by bolus of sterile water, injected through a spinal needle into the exit foramen and adjacent epidural space for neuroprotection, is a safe and effective procedure. (orig.)

Increase in Volume of Ablation Zones during Follow-up Is Highly Suggestive of Ablation Site Recurrence in Colorectal Liver Metastases Treated with Radiofrequency Ablation

NARCIS (Netherlands)

Kele, Petra G.; de Jong, Koert P.; van der Jagt, Eric J.

Purpose: To test the hypothesis that volume changes of ablation zones (AZs) on successive computed tomography (CT) scans could predict ablation site recurrences (ASRs) in patients with colorectal liver metastases treated by radiofrequency (RF) ablation. Materials and Methods: RF ablation was

Accuracy and efficacy of percutaneous biopsy and ablation using robotic assistance under computed tomography guidance: a phantom study

International Nuclear Information System (INIS)

Koethe, Yilun; Xu, Sheng; Velusamy, Gnanasekar; Wood, Bradford J.; Venkatesan, Aradhana M.

2014-01-01

To compare the accuracy of a robotic interventional radiologist (IR) assistance platform with a standard freehand technique for computed-tomography (CT)-guided biopsy and simulated radiofrequency ablation (RFA). The accuracy of freehand single-pass needle insertions into abdominal phantoms was compared with insertions facilitated with the use of a robotic assistance platform (n = 20 each). Post-procedural CTs were analysed for needle placement error. Percutaneous RFA was simulated by sequentially placing five 17-gauge needle introducers into 5-cm diameter masses (n = 5) embedded within an abdominal phantom. Simulated ablations were planned based on pre-procedural CT, before multi-probe placement was executed freehand. Multi-probe placement was then performed on the same 5-cm mass using the ablation planning software and robotic assistance. Post-procedural CTs were analysed to determine the percentage of untreated residual target. Mean needle tip-to-target errors were reduced with use of the IR assistance platform (both P < 0.0001). Reduced percentage residual tumour was observed with treatment planning (P = 0.02). Improved needle accuracy and optimised probe geometry are observed during simulated CT-guided biopsy and percutaneous ablation with use of a robotic IR assistance platform. This technology may be useful for clinical CT-guided biopsy and RFA, when accuracy may have an impact on outcome. (orig.)

Accuracy and efficacy of percutaneous biopsy and ablation using robotic assistance under computed tomography guidance: a phantom study

Energy Technology Data Exchange (ETDEWEB)

Koethe, Yilun [National Institutes of Health, Center for Interventional Oncology, NIH Clinical Center, Bethesda, MD (United States); National Institutes of Health, Radiology and Imaging Sciences, NIH Clinical Center, Bethesda, MD (United States); Duke University School of Medicine, Durham, NC (United States); Xu, Sheng [National Institutes of Health, Center for Interventional Oncology, NIH Clinical Center, Bethesda, MD (United States); Velusamy, Gnanasekar [Perfint Healthcare Pvt. Ltd., Chennai (India); Wood, Bradford J. [National Institutes of Health, Center for Interventional Oncology, NIH Clinical Center, Bethesda, MD (United States); National Institutes of Health, Radiology and Imaging Sciences, NIH Clinical Center, Bethesda, MD (United States); Venkatesan, Aradhana M. [National Institutes of Health, Center for Interventional Oncology, NIH Clinical Center, Bethesda, MD (United States); National Institutes of Health, Radiology and Imaging Sciences, NIH Clinical Center, Bethesda, MD (United States); National Institutes of Health, Center for Interventional Oncology, Radiology and Imaging Sciences, NIH Clinical Center, Bethesda, MD (United States)

2014-03-15

To compare the accuracy of a robotic interventional radiologist (IR) assistance platform with a standard freehand technique for computed-tomography (CT)-guided biopsy and simulated radiofrequency ablation (RFA). The accuracy of freehand single-pass needle insertions into abdominal phantoms was compared with insertions facilitated with the use of a robotic assistance platform (n = 20 each). Post-procedural CTs were analysed for needle placement error. Percutaneous RFA was simulated by sequentially placing five 17-gauge needle introducers into 5-cm diameter masses (n = 5) embedded within an abdominal phantom. Simulated ablations were planned based on pre-procedural CT, before multi-probe placement was executed freehand. Multi-probe placement was then performed on the same 5-cm mass using the ablation planning software and robotic assistance. Post-procedural CTs were analysed to determine the percentage of untreated residual target. Mean needle tip-to-target errors were reduced with use of the IR assistance platform (both P < 0.0001). Reduced percentage residual tumour was observed with treatment planning (P = 0.02). Improved needle accuracy and optimised probe geometry are observed during simulated CT-guided biopsy and percutaneous ablation with use of a robotic IR assistance platform. This technology may be useful for clinical CT-guided biopsy and RFA, when accuracy may have an impact on outcome. (orig.)

The effect of elastic modulus on ablation catheter contact area.

Science.gov (United States)

Camp, Jon J; Linte, Cristian A; Rettmann, Maryam E; Sun, Deyu; Packer, Douglas L; Robb, Richard A; Holmes, David R

2015-02-21

Cardiac ablation consists of navigating a catheter into the heart and delivering RF energy to electrically isolate tissue regions that generate or propagate arrhythmia. Besides the challenges of accurate and precise targeting of the arrhythmic sites within the beating heart, limited information is currently available to the cardiologist regarding intricate electrode-tissue contact, which directly impacts the quality of produced lesions. Recent advances in ablation catheter design provide intra-procedural estimates of tissue-catheter contact force, but the most direct indicator of lesion quality for any particular energy level and duration is the tissue-catheter contact area, and that is a function of not only force, but catheter pose and material elasticity as well. In this experiment, we have employed real-time ultrasound (US) imaging to determine the complete interaction between the ablation electrode and tissue to accurately estimate contact, which will help to better understand the effect of catheter pose and position relative to the tissue. By simultaneously recording tracked position, force reading and US image of the ablation catheter, the differing material properties of polyvinyl alcohol cryogel [1] phantoms are shown to produce varying amounts of tissue depression and contact area (implying varying lesion quality) for equivalent force readings. We have shown that the elastic modulus significantly affects the surface-contact area between the catheter and tissue at any level of contact force. Thus we provide evidence that a prescribed level of catheter force may not always provide sufficient contact area to produce an effective ablation lesion in the prescribed ablation time.

Radiofrequency ablation of lung and liver lesions using CT fluoroscopy

International Nuclear Information System (INIS)

Chai, A.; Glenn, D.

2002-01-01

Full text: Tumour ablation with radiofrequency (RF) energy is a relatively new procedure for the treatment of focal malignant disease. At our institution this is currently being used in the treatment of certain liver and lung lesions with the patients involved being enrolled in clinical trials. The poster describes the technique used at our institution for the placement of the radiofrequency ablation electrode using CT fluoroscopy. Criteria for patient selection are included. Complications from the procedure are described, as well as follow up appearances and results. Our results from the treatment of primary and secondary lesions in the liver correlate well with published literature. Treatment is still not as successful as surgical resection but there is significantly less morbidity. Where this method may be appropriate is when the patient is not a candidate for surgical resection. The treatment of colorectal metastases in the lung shows early promise as a possible second line treatment (as for liver) where the patient is not a candidate for surgery. Preliminary results are soon to be published in conjunction with the Department of Surgery at our institution. RF Electrode placement using CT Fluoroscopy is performed at our institution. While still at its early stages, RF Ablation shows promise as a possible second line treatment (with other adjuvant therapy) for the management of focal malignant disease in the lung and liver. Copyright (2002) Blackwell Science Pty Ltd

Increased resting heart rate following radiofrequency catheter ablation for atrial fibrillation

DEFF Research Database (Denmark)

Nilsson, Brian; Chen, Xu; Pehrson, Steen

2005-01-01

the procedure. RESULTS: Following PV isolation, the mean HR significantly increased from 58 +/- 10 bpm at baseline to 67 +/- 12 bpm at one month, 71 +/- 13 bpm at three months, 69 +/- 12 bpm at six months, 69 +/- 13 at nine months, and 70 +/- 13 at 12 months follow-up. The ablation success significantly...... correlated with the increase in HR at one month follow-up. In three patients the mean HR increased > 25 bpm resulting in symptoms necessitating therapy with rate-controlling drugs. CONCLUSION: PV isolation in patients with AF may result in increased HR, which positively correlated with the ablation success...

The effect of radiofrequency ablation on different organs: Ex vivo and in vivo comparative studies

Energy Technology Data Exchange (ETDEWEB)

Kim, Yoo Na [Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-dong, Kangnam-Ku, Seoul 135-710 (Korea, Republic of); Rhim, Hyunchul, E-mail: rhimhc@skku.edu [Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-dong, Kangnam-Ku, Seoul 135-710 (Korea, Republic of); Choi, Dongil; Kim, Young-sun; Lee, Min Woo; Chang, Ilsoo; Lee, Won Jae; Lim, Hyo K. [Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-dong, Kangnam-Ku, Seoul 135-710 (Korea, Republic of)

2011-11-15

Objective: The purposes of this study are to evaluate the ex vivo and in vivo efficacy of radiofrequency ablation (RFA) on different porcine tissues by the ablation of three different sites simultaneously. Materials and methods: A multichannel RFA system, enables three separate tumors to be ablated simultaneously, was used. RFA procedures were applied to normal porcine liver, kidney, and muscle together ex vivo (n = 12) and in vivo (n = 17). Pre-impedances, defined as baseline systemic impedances of tissues before beginning RFA, and the areas of ablation zones were measured and compared. Results: The areas of ablation zones among three organs had a significant difference in decreasing order as follows: liver, muscle, and kidney in the ex vivo study (p = 0.001); muscle, liver, and kidney in the in vivo study (p < 0.0001). The areas of ablation zones between ex vivo and in vivo had a significant difference in the liver and muscle (each p < 0.05). There was no significant correlation between the areas of ablation zones and pre-impedances in both studies. Conclusions: Renal RFA produced the smallest ablation zone in both in vivo and ex vivo studies. Muscular RFA demonstrated the largest ablation zone in the in vivo study, and hepatic RFA showed the largest ablation zone in the ex vivo study. This variability in the tissues should be considered for performing an optimized RFA for each organ site.

Radiation protection of cyclotron vault with maze in PET Cyclotron Center

International Nuclear Information System (INIS)

Fueloep, Marko

2003-01-01

The PET Cyclotron center (PCC) is a complex for production, research and application of positron radiopharmaceuticals for PET (Positron Emission Tomography), which was commissioned this year (2004) in Bratislava, Slovak Republic. Positron radionuclides are produced by 18/9 MeV proton/deuteron cyclotron CYCLONE 18/9. Radiation protection of personnel and inhabitants against ionizing radiation in the PCC is solved with regard to the ICRP recommendations and Slovak regulatory system, protection rules and criteria and optimization of radiation protection. In the article comparisons of calculated and measured neutron and gamma dose equivalent rates around the CYCLONE 18/9 and at various points behind the shielding of cyclotron vault with maze are presented. Description of the CYCLONE 18/9 as a source of angular distribution of neutron energy spectra (production of 18 F was considered) was simulated by Monte Carlo code MCNPX. Code MCNP4B was used for shielding calculation of cyclotron vault with maze. Neutron energy spectra behind the shielding were measured by Bonner spectrometer. The values of neutron dose equivalent, which were calculated and measured around the CYCLONE 18/9 and at various points behind the shielding of cyclotron vault with maze, are within the range of factor 2. (authors)

Pulmonary ablation: a primer.

Science.gov (United States)

Roberton, Benjamin J; Liu, David; Power, Mark; Wan, John M C; Stuart, Sam; Klass, Darren; Yee, John

2014-05-01

Percutaneous image-guided thermal ablation is safe and efficacious in achieving local control and improving outcome in the treatment of both early stage non-small-cell lung cancer and pulmonary metastatic disease, in which surgical treatment is precluded by comorbidity, poor cardiorespiratory reserve, or unfavorable disease distribution. Radiofrequency ablation is the most established technology, but new thermal ablation technologies such as microwave ablation and cryoablation may offer some advantages. The use of advanced techniques, such as induced pneumothorax and the popsicle stick technique, or combining thermal ablation with radiotherapy, widens the treatment options available to the multidisciplinary team. The intent of this article is to provide the reader with a practical knowledge base of pulmonary ablation by concentrating on indications, techniques, and follow-up. Copyright © 2014 Canadian Association of Radiologists. Published by Elsevier Inc. All rights reserved.

Lung Tumor Radiofrequency Ablation: Where Do We Stand?

International Nuclear Information System (INIS)

Baère, Thierry de

2011-01-01

Today, radiofrequency ablation (RFA) of primary and metastatic lung tumor is increasingly used. Because RFA is most often used with curative intent, preablation workup must be a preoperative workup. General anesthesia provides higher feasibility than conscious sedation. The electrode positioning must be performed under computed tomography for sake of accuracy. The delivery of RFA must be adapted to tumor location, with different impedances used when treating tumors with or without pleural contact. The estimated rate of incomplete local treatment at 18 months was 7% (95% confidence interval, 3–14) per tumor, with incomplete treatment depicted at 4 months (n = 1), 6 months (n = 2), 9 months (n = 2), and 12 months (n = 2). Overall survival and lung disease-free survival at 18 months were, respectively, 71 and 34%. Size is a key point for tumor selection because large size is predictive of incomplete local treatment and poor survival. The ratio of ablation volume relative to tumor volume is predictive of complete ablation. Follow-up computed tomography that relies on the size of the ablation zone demonstrates the presence of incomplete ablation. Positron emission tomography might be an interesting option. Chest tube placement for pneumothorax is reported in 8 to 12%. Alveolar hemorrhage and postprocedure hemoptysis occurred in approximately 10% of procedures and rarely required specific treatment. Death was mostly related to single-lung patients and hilar tumors. No modification of forced expiratory volume in the first second between pre- and post-RFA at 2 months was found. RFA in the lung provides a high local efficacy rate. The use of RFA as a palliative tool in combination with chemotherapy remains to be explored.

Percutaneous radiofrequency and microwave ablation in the treatment of renal tumors - 10 years of experience.

Science.gov (United States)

Dvorak, Petr; Hoffmann, Petr; Brodak, Milos; Kosina, Josef; Pacovsky, Jaroslav; Raupach, Jan; Krajina, Antonin

2017-12-01

The standard radical treatment of renal cell carcinoma is surgical resection, but it is not suitable for patients with serious medical comorbidities and solitary kidney tumors. Minimally invasive ablation techniques could be an appropriate therapeutic alternative. To retrospectively evaluate the technical success, mid-term and long-term efficacy and safety of radiofrequency and microwave ablation in patients with small renal tumors. Over the course of 10 years, 91 ablation procedures in 64 patients for 68 tumors, of size 12-60 mm, were performed using only conscious sedation. These ablations were done under the guidance of computed tomography. We treated 41 males and 23 females with solitary kidney tumors (14 cases) and tumors in non-surgical candidates (54 cases). In 50 (73.5%) tumors single treatment was successful; in 13 (19.1%) cases a second procedure was used successfully, and in the 5 largest tumors (sizes 45-60 mm, 7.4%) a third treatment was necessary. Within the follow-up 10 (15.6%) patients died, but none due to metastatic renal cell carcinoma. Only 1 serious complication was observed - retroperitoneal and psoatic hematoma. Early recurrence occurred in 18 (26.5%) tumors. Late recurrence was detected in 5 (7.4%) cases. In all cases complete local control of the renal tumors was reached. Percutaneous ablation is a very effective treatment for patients with small renal tumors of the T1a group with a minimal complication rate.

Radiofrequency ablation of small hepatocellular carcinoma : early experience of efficacy and safety

International Nuclear Information System (INIS)

Choi, Dongil; Lim, Hyo Keun; Kim, Seung Hoon; And Others

2000-01-01

To evaluate the efficacy and safety of radiofrequency (RF) ablation for the treatment of small hepatocellular carcinoma (HCC). Forty-four patients with 51 HCCs underwent ultrasound guided RF ablation using expandable needle electrodes and monopolar RF generator. The patients were not considered suitable candidates for surgery or declined this option, and had no history of previous treatment. Mean tumor diameter was 2.5 cm (range, 1.0-4.0 cm). Therapeutic efficacy was evaluated by means of three-phase helical computed tomography (CT) performed at least one month after the completion of ablation. The recurrence rate was also evaluated by follow-up CT at least four months after treatment. Using RF ablation, complete necrosis was achieved in 48 of 51 tumors (94%). Among 20 patients in whom follow-up CT was performed at least four months after ablation, one (5%) showed marginal recurrence and in another (5%) there was recurrence in remote liver parenchyma. We experienced neither procedure-related mortality nor major complications which required specific treatment. Three minor complications (one small pneumothorax and two cases of intraperitoneal bleeding) occurred, but these disappeared without specific treatment. RF ablation using an expandable needle electrode showed a high rate of complete necrosis and a low rate of complications. The technique is therefore considered effective and safe for the local control of small HCCs. (author)

Laparoscopic microwave thermosphere ablation of malignant liver tumors: An analysis of 53 cases.

Science.gov (United States)

Zaidi, Nisar; Okoh, Alexis; Yigitbas, Hakan; Yazici, Pinar; Ali, Noaman; Berber, Eren

2016-02-01

Microwave thermosphere ablation (MTA) is a new technology that is designed to create spherical zones of ablation using a single antenna. The aim of this study is to assess the results of MTA in a large series of patients. This was a prospective study assessing the use of MTA in patients with malignant liver tumors. The procedures were done mostly laparoscopically and ablation zones created were assessed for completeness of tumor response, spherical geometry and recurrence on tri-phasic CT scans done on follow-up. There were a total of 53 patients with an average of 3 tumors measuring 1.5 cm. Ablations were performed laparoscopically in all but eight patients. Morbidity was 11.3% (n = 6), and mortality zero. On postoperative scans, there was 99.3% tumor destruction. Roundness indices A, B, and transverse were 1.1, 1.0, and 0.9, respectively. At a median follow-up of 4.5 months, incomplete ablation was seen in 1 of 149 lesions treated (0.7%) and local tumor recurrence in 1 lesion (0.7%). The results of this series confirm the safety and feasibility of MTA technology. The 99.3% rate of complete tumor ablation and low rate of local recurrence at short-term follow up are promising. © 2015 Wiley Periodicals, Inc.

The contemporary role of ablative treatment approaches in the management of renal cell carcinoma (RCC): focus on radiofrequency ablation (RFA), high-intensity focused ultrasound (HIFU), and cryoablation.

Science.gov (United States)

Klatte, Tobias; Kroeger, Nils; Zimmermann, Uwe; Burchardt, Martin; Belldegrun, Arie S; Pantuck, Allan J

2014-06-01

Currently, most of renal tumors are small, low grade, with a slow growth rate, a low metastatic potential, and with up to 30 % of these tumors being benign on the final pathology. Moreover, they are often diagnosed in elderly patients with preexisting medical comorbidities in whom the underlying medical conditions may pose a greater risk of death than the small renal mass. Concerns regarding overdiagnosis and overtreatment of patients with indolent small renal tumors have led to an increasing interest in minimally invasive, ablative as an alternative to extirpative interventions for selected patients. To provide an overview about the state of the art in radiofrequency ablation (RFA), high-intensity focused ultrasound, and cryoablation in the clinical management of renal cell carcinoma. A PubMed wide the literature search of was conducted. International consensus panels recommend ablative techniques in patients who are unfit for surgery, who are not considered candidates for or elect against elective surveillance, and who have small renal masses. The most often used techniques are cryoablation and RFA. These ablative techniques offer potentially curative outcomes while conferring several advantages over extirpative surgery, including improved patient procedural tolerance, faster recovery, preservation of renal function, and reduction in the risk of intraoperative and postsurgical complications. While it is likely that outcomes associated with ablative modalities will improve with further advances in technology, their application will expand to more elective indications as longer-term efficacy data become available. Ablative techniques pose a valid treatment option in selected patients.

Comparison of microbubble presence in the right heart during mechanochemical and radiofrequency ablation for varicose veins.

Science.gov (United States)

Moon, K H; Dharmarajah, B; Bootun, R; Lim, C S; Lane, Tra; Moore, H M; Sritharan, K; Davies, A H

2017-07-01

Objective Mechanochemical ablation is a novel technique for ablation of varicose veins utilising a rotating catheter and liquid sclerosant. Mechanochemical ablation and radiofrequency ablation have no reported neurological side-effect but the rotating mechanism of mechanochemical ablation may produce microbubbles. Air emboli have been implicated as a cause of cerebrovascular events during ultrasound-guided foam sclerotherapy and microbubbles in the heart during ultrasound-guided foam sclerotherapy have been demonstrated. This study investigated the presence of microbubbles in the right heart during varicose vein ablation by mechanochemical abaltion and radiofrequency abaltion. Methods Patients undergoing great saphenous vein ablation by mechanochemical abaltion or radiofrequency ablation were recruited. During the ablative procedure, the presence of microbubbles was assessed using transthoracic echocardiogram. Offline blinded image quantification was performed using International Consensus Criteria grading guidelines. Results From 32 recruited patients, 28 data sets were analysed. Eleven underwent mechanochemical abaltion and 17 underwent radiofrequency abaltion. There were no neurological complications. In total, 39% (11/28) of patients had grade 1 or 2 microbubbles detected. Thirty-six percent (4/11) of mechanochemical abaltion patients and 29% (5/17) of radiofrequency ablation patients had microbubbles with no significant difference between the groups ( p=0.8065). Conclusion A comparable prevalence of microbubbles between mechanochemical abaltion and radiofrequency ablation both of which are lower than that previously reported for ultrasound-guided foam sclerotherapy suggests that mechanochemical abaltion may not confer the same risk of neurological events as ultrasound-guided foam sclerotherapy for treatment of varicose veins.

Endovascular Radiofrequency Ablation for Varicose Veins

Science.gov (United States)

2011-01-01

treatment plan. The RFA procedure involves the introduction of a guide wire into the target vein under ultrasound guidance followed by the insertion of an introducer sheath through which the RFA catheter is advanced. Once satisfactory positioning has been confirmed with ultrasound, a tumescent anaesthetic solution is injected into the soft tissue surrounding the target vein along its entire length. This serves to anaesthetize the vein, insulate the heat from damaging adjacent structures, including nerves and skin and compresses the vein increasing optimal contact of the vessel wall with the electrodes or expanded prongs of the RF device. The RF generator is then activated and the catheter is slowly pulled along the length of the vein. At the end of the procedure, hemostasis is then achieved by applying pressure to the vein entry point. Adequate and proper compression stockings and bandages are applied after the procedure to reduce the risk of venous thromboembolism and to reduce postoperative bruising and tenderness. Patients are encouraged to walk immediately after the procedure. Follow-up protocols vary, with most patients returning 1 to 3 weeks later for an initial follow-up visit. At this point, the initial clinical result is assessed and occlusion of the treated vessels is confirmed with ultrasound. Patients often have a second follow-up visit 1 to 3 months following RFA at which time clinical evaluation and ultrasound are repeated. If required, additional procedures such as phlebectomy or sclerotherapy may be performed during the RFA procedure or at any follow-up visits. Regulatory Status The Closure System® radiofrequency generator for endovascular thermal ablation of varicose veins was approved by Health Canada as a class 3 device in March 2005, registered under medical device license 67865. The RFA intravascular catheter was approved by Health Canada in November 2007 for the ClosureFast catheter, registered under medical device license 16574. The Closure System

Effect of variable heat transfer coefficient on tissue temperature next to a large vessel during radiofrequency tumor ablation

Directory of Open Access Journals (Sweden)

Pinheiro Cleber

2008-07-01

Full Text Available Abstract Background One of the current shortcomings of radiofrequency (RF tumor ablation is its limited performance in regions close to large blood vessels, resulting in high recurrence rates at these locations. Computer models have been used to determine tissue temperatures during tumor ablation procedures. To simulate large vessels, either constant wall temperature or constant convective heat transfer coefficient (h have been assumed at the vessel surface to simulate convection. However, the actual distribution of the temperature on the vessel wall is non-uniform and time-varying, and this feature makes the convective coefficient variable. Methods This paper presents a realistic time-varying model in which h is a function of the temperature distribution at the vessel wall. The finite-element method (FEM was employed in order to model RF hepatic ablation. Two geometrical configurations were investigated. The RF electrode was placed at distances of 1 and 5 mm from a large vessel (10 mm diameter. Results When the ablation procedure takes longer than 1–2 min, the attained coagulation zone obtained with both time-varying h and constant h does not differ significantly. However, for short duration ablation (5–10 s and when the electrode is 1 mm away from the vessel, the use of constant h can lead to errors as high as 20% in the estimation of the coagulation zone. Conclusion For tumor ablation procedures typically lasting at least 5 min, this study shows that modeling the heat sink effect of large vessels by applying constant h as a boundary condition will yield precise results while reducing computational complexity. However, for other thermal therapies with shorter treatment using a time-varying h may be necessary.

Acute stress switches spatial navigation strategy from egocentric to allocentric in a virtual Morris water maze.

Science.gov (United States)

van Gerven, Dustin J H; Ferguson, Thomas; Skelton, Ronald W

2016-07-01

Stress and stress hormones are known to influence the function of the hippocampus, a brain structure critical for cognitive-map-based, allocentric spatial navigation. The caudate nucleus, a brain structure critical for stimulus-response-based, egocentric navigation, is not as sensitive to stress. Evidence for this comes from rodent studies, which show that acute stress or stress hormones impair allocentric, but not egocentric navigation. However, there have been few studies investigating the effect of acute stress on human spatial navigation, and the results of these have been equivocal. To date, no study has investigated whether acute stress can shift human navigational strategy selection between allocentric and egocentric navigation. The present study investigated this question by exposing participants to an acute psychological stressor (the Paced Auditory Serial Addition Task, PASAT), before testing navigational strategy selection in the Dual-Strategy Maze, a modified virtual Morris water maze. In the Dual-Strategy maze, participants can chose to navigate using a constellation of extra-maze cues (allocentrically) or using a single cue proximal to the goal platform (egocentrically). Surprisingly, PASAT stress biased participants to solve the maze allocentrically significantly more, rather than less, often. These findings have implications for understanding the effects of acute stress on cognitive function in general, and the function of the hippocampus in particular. Copyright © 2016 Elsevier Inc. All rights reserved.

Tactile maze solving in congenitally blind individuals

DEFF Research Database (Denmark)

Gagnon, Léa; Kupers, Ron; Schneider, Fabien C

2010-01-01

and environmental cues such as temperature and echolocation. We hypothesize that by limiting these cues, blind individuals will lose their advantage compared with controls in spatial navigation tasks. We therefore evaluated the performance of blind and sighted individuals in small-scale, tactile multiple T mazes....... Our results show that blindfolded sighted controls outperformed blind participants in the route-learning tasks. This suggests that, contrary to indoor large-scale spaces, navigational skills inside small-scale spaces benefit from visual experience....

Comparing Exploration Strategies for Q-learning in Random Stochastic Mazes

NARCIS (Netherlands)

Tijsma, Arryon; Drugan, Madalina; Wiering, Marco

2016-01-01

Balancing the ratio between exploration and exploitation is an important problem in reinforcement learning. This paper evaluates four different exploration strategies combined with Q-learning using random stochastic mazes to investigate their performances. We will compare: UCB-1, softmax,

Improving Students’ English Pronunciation Ability Through Go Fish Game and Maze Game

Directory of Open Access Journals (Sweden)

Dwi Astuti Wahyu Nurhayati

2015-12-01

Full Text Available The problem highlighted in this research is the low pronunciation ability of Kindergarten students in Al-Irsyad  Madiun  that is caused by (1 the uninteresting activities in learning English; (2 the students' difficulties in pronunciating English words; (3 the students' low motivation in learning. The theoretical review includes the young learners characteristics, games in language, games for young learners. The procedure of the research consists of identifying the problem, planning the action, implementing the action, observing the action, and reflecting the result of the research. In this research, the researcher acts as the teacher who conducts the action research in the classroom and she is helped by the classsroom teacher. In collecting the data, the researcher uses observational technique supported with tests. In analyzing the data, the researcher uses the field notes, teacher's diaries, students ‘work supported with the cassette recording and photograph,then also compares the result of the students' pre-test and post-test to answer the research questions. There is significant improvement in the result of pre-test and post-test of cycle 1 and 2. In cycle 1, t0 (2.55734 is higher than tt (1.73 and in cycle 2, t0 (6.765738 is also higher than tt (1.73. From these two results, therefore, h0 is rejected and the alternative hypothesis (ha is accepted. They practice their pronunciation through taking turn and asking each other for cards to match those they have in their hands, arranging a word and sticking on alphabet, pronunciating the word, giving the meaning, hen making a sentence such as Go Fish Game and Maze Game. By conducting these games, using interesting media, creating various interesting tasks and activities can increase the students' motivation in learning English and pronunciation ability.Keywords: Improving, pronunciation, ability,  go fish and Maze games

Fiber-Optic Temperature and Pressure Sensors Applied to Radiofrequency Thermal Ablation in Liver Phantom: Methodology and Experimental Measurements

Directory of Open Access Journals (Sweden)

Daniele Tosi

2015-01-01

Full Text Available Radiofrequency thermal ablation (RFA is a procedure aimed at interventional cancer care and is applied to the treatment of small- and midsize tumors in lung, kidney, liver, and other tissues. RFA generates a selective high-temperature field in the tissue; temperature values and their persistency are directly related to the mortality rate of tumor cells. Temperature measurement in up to 3–5 points, using electrical thermocouples, belongs to the present clinical practice of RFA and is the foundation of a physical model of the ablation process. Fiber-optic sensors allow extending the detection of biophysical parameters to a vast plurality of sensing points, using miniature and noninvasive technologies that do not alter the RFA pattern. This work addresses the methodology for optical measurement of temperature distribution and pressure using four different fiber-optic technologies: fiber Bragg gratings (FBGs, linearly chirped FBGs (LCFBGs, Rayleigh scattering-based distributed temperature system (DTS, and extrinsic Fabry-Perot interferometry (EFPI. For each instrument, methodology for ex vivo sensing, as well as experimental results, is reported, leading to the application of fiber-optic technologies in vivo. The possibility of using a fiber-optic sensor network, in conjunction with a suitable ablation device, can enable smart ablation procedure whereas ablation parameters are dynamically changed.

An experimental study on hepatic ablation using an expandable radio-frequency needle electrode

International Nuclear Information System (INIS)

Choi, Dong Il; Lim, Hyo Keun; Park, Jong Min; Kang, Bo Kyung; Woo, Ji Young; Jang, Hyun Jung; Kim, Seung Hoon; Lee, Won Jae; Park, Cheol Keun; Heo, Jin Seok

1999-01-01

The purpose of this study was to determine the factors influencing on the size of thermal lesions after ablation using an expendable radio-frequency needle electrode in porcine liver. Ablation procedures involved the use of a monopolar radio-frequency generator and 15-G needle electrodes with four and seven retractable hooks (RITA Medical System, Mountain View, Cal., U.S.A.). The ablation protocol in fresh porcine liver comprised of combinations of varying hook deployment, highest set temperature, and ablation time. Following ablation, the maximum diameter of all thermal lesions was measured on a longitudinal section of the specimen. Ten representive lesions were examined by an experienced pathologist. At 3-cm hook deployment of the needle electrode with four lateral hooks, the size of spherical thermal lesions increased substantially with increases in the highest set temperature and ablation time until 11 minutes. After 11 minutes lesion size remained similar, with a maximum diameter of 3.3 cm. At 2-cm hook deployment, sizes decreased to about 2/3 of those at 3 cm , and at 1-cm hook deployment lesions were oblong. At 3-cm hook deployment of a needle electrode with seven hooks, the size of thermal lesions increased with increasing ablation time until 14 minutes, and the maximum diameter was 4.1 cm. Microscopic examination showed a wide zone of degeneration and focal coagulation necrosis. The size of thermal lesions produced by the use of an expandable radio-frequency needle electrode were predictable, varying according to degree of hook deployment, highest set temperature, and ablation time

Utility of finger maze test for learning and memory abilities in infants of cynomolgus monkeys exposed to thiamazole.

Science.gov (United States)

Inoue, Ayumi; Arima, Akihiro; Kato, Hirohito; Ebihara, Shizufumi

2014-11-01

A new type of learning and memory test using a finger maze was conducted in infant cynomolgus monkeys that were exposed to thiamazole (2 and 3.5 mg/kg per day to pregnant animals orally) during the fetal period (gestational days 120 to 150). We modified Tsuchida's original finger maze test method by reducing the number of trials per day and simplifying the criteria for achievement of training, and we added a long-term memory test. In the memory test, thiamazole-exposed infants required greater time to complete the finger maze test than the control infants although no effect was noted in the training or learning test. The results suggest that an impaired long-term memory could be detected by our modified finger maze test. © 2014 Japanese Teratology Society.

Protection of skin with subcutaneous administration of 5% dextrose in water during superficial radiofrequency ablation in a rabbit model.

Science.gov (United States)

Guo, Hui; Liu, Xia-Lei; Wang, Yu-Ling; Li, Jing-Yi; Lu, Wu-Zhu; Xian, Jian-Zhong; Zhang, Bai-Meng; Li, Jian

2014-06-01

This study was to evaluate the efficacy of subcutaneous administration of 5% dextrose in water (D5W), to prevent skin injury during radiofrequency (RF) ablation. Twenty-four rabbits were divided into three groups: a pre-injection group, a perfusion group, and a control group. Ablative zones were created in the superficial part of the thigh muscle for 6 min. A needle was placed subcutaneously for injection of D5W, and a thermal sensor was positioned nearby for real-time temperature monitoring. The sizes of the ablative zones were measured by contrast-enhanced ultrasonography, and severity of the observed skin injury were scored semi-quantitatively and compared. The highest temperature, the duration of the temperature above 50 °C, and the rise time of the post-procedure temperature were all highest in the control group (p skin injury was most severe in the control group (p skin injury of the pre-injection group and the perfusion group (p = 0.091), while the skin injury of the perfusion group was less severe than that of the pre-injection group on post-procedure day 14 (p = 0.004). No significant difference was found in the sizes of the ablative zones among the groups (p = 0.720). Subcutaneous perfusion with D5W is effective in protecting the skin against burns during RF ablation without compromising the effect of ablation.

Microglial ablation and lipopolysaccharide preconditioning affects pilocarpine-induced seizures in mice

Energy Technology Data Exchange (ETDEWEB)

Mirrione, M.M.; Mirrione, M.M.; Konomosa, D.K.; Ioradanis, G.; Dewey, S.L.; Agzzid, A.; Heppnerd, F.L.; Tsirka, St.E.

2010-04-01

Activated microglia have been associated with neurodegeneration in patients and in animal models of Temporal Lobe Epilepsy (TLE), however their precise functions as neurotoxic or neuroprotective is a topic of significant investigation. To explore this, we examined the effects of pilocarpine-induced seizures in transgenic mice where microglia/macrophages were conditionally ablated. We found that unilateral ablation of microglia from the dorsal hippocampus did not alter acute seizure sensitivity. However, when this procedure was coupled with lipopolysaccharide (LPS) preconditioning (1 mg/kg given 24 h prior to acute seizure), we observed a significant pro-convulsant phenomenon. This effect was associated with lower metabolic activation in the ipsilateral hippocampus during acute seizures, and could be attributed to activity in the mossy fiber pathway. These findings reveal that preconditioning with LPS 24 h prior to seizure induction may have a protective effect which is abolished by unilateral hippocampal microglia/macrophage ablation.

[Interventional radiology procedures for malignancies of the liver treatment: Intraarterial procedures].

Science.gov (United States)

Cristina, V; Pracht, M; Lachenal, Y; Adib, S; Boubaker, A; Prior, J; Senys, A; Wagner, A D; Bize, P

2014-05-21

Intraarterial procedures such as chemoembolization and radioembolization aim for the palliative treatment of advanced hepatocellular carcinoma (stage BCLC B and C with tumoral portal thrombosis). The combination of hepatic intraarterial chemotherapy and systemic chemotherapy can increase the probability of curing colorectal cancer with hepatic metastases not immediately accessible to surgical treatment or percutaneous ablation.

Ablation threshold and ablation mechanism transition of polyoxymethylene irradiated by CO2 laser.

Science.gov (United States)

Li, Gan; Cheng, Mousen; Li, Xiaokang

2016-09-01

Polyoxymethylene (POM) decomposes gradually as it is heated up by the irradiation of CO2 laser; the long-chain molecules of POM are broken into short chains, which leads to the lowering of the melting point and the critical temperature of the ablation products. When the product temperature is above the melting point, ablation comes up in the way of vaporization; when the product temperature is higher than the critical temperature, all liquid products are transformed into gas instantly and the ablation mechanism is changed. The laser fluence at which significant ablation is observed is defined as the ablation threshold, and the fluence corresponding to the ablation mechanism changing is denoted as the flyover threshold. In this paper, random pyrolysis is adopted to describe the pyrolytic decomposition of POM, and consequently, the components of the pyrolysis products under different pyrolysis rates are acquired. The Group Contribution method is used to count the thermodynamic properties of the pyrolysis products, and the melting point and the critical temperature of the product mixture are obtained by the Mixing Law. The Knudsen layer relationship is employed to evaluate the ablation mass removal when the product temperature is below the critical temperature. The gas dynamics conservation laws associated with the Jouguet condition are used to calculate the mass removal when the product temperature is higher than the critical temperature. Based on the model, a set of simulations for various laser intensities and lengths are carried out to generalize the relationships between the thresholds and the laser parameters. Besides the ablated mass areal density, which fits the experimental data quite well, the ablation temperature, pyrolysis rate, and product components are also discussed for a better understanding of the ablation mechanism of POM.

Catheter ablation as a treatment of atrioventricular block.

Science.gov (United States)

Tuohy, Stephen; Saliba, Walid; Pai, Manjunath; Tchou, Patrick

2018-01-01

Symptomatic second-degree atrioventricular (AV) block is typically treated by implantation of a pacemaker. An otherwise healthy AV conduction system can nevertheless develop AV block due to interference from junctional extrasystoles. When present with a high burden, these can produce debilitating symptoms from AV block despite an underlying normal AV node and His-Purkinje system properties. The purpose of this study was to describe a catheter ablation approach for alleviating symptomatic AV block due to a ventricular nodal pathway interfering with AV conduction. Common clinical monitoring techniques such as Holter and event recorders were used. Standard electrophysiological study techniques using multipolar recording and ablation catheters were utilized during procedures. A 55-year-old woman presented with highly symptomatic, high-burden second-degree AV block due to concealed and manifest junctional premature beats. Electrophysiological characteristics indicated interference of AV conduction due to a concealed ventricular nodal pathway as the cause of the AV block. The patient's AV nodal and His-Purkinje system conduction characteristics were otherwise normal. Radiofrequency catheter ablation of the pathway was successful in restoring normal AV conduction and eliminating her clinical symptoms. Pathways inserting into the AV junction can interfere with AV conduction. When present at a high burden, this type of AV block can be highly symptomatic. Catheter ablation techniques can be used to alleviate this type of AV block and restore normal AV conduction. Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Atrial fibrillation ablation using a closed irrigation radiofrequency ablation catheter.

Science.gov (United States)

Golden, Keith; Mounsey, John Paul; Chung, Eugene; Roomiani, Pahresah; Morse, Michael Andew; Patel, Ankit; Gehi, Anil

2012-05-01

Catheter ablation is an effective therapy for symptomatic, medically refractory atrial fibrillation (AF). Open-irrigated radiofrequency (RF) ablation catheters produce transmural lesions at the cost of increased fluid delivery. In vivo models suggest closed-irrigated RF catheters create equivalent lesions, but clinical outcomes are limited. A cohort of 195 sequential patients with symptomatic AF underwent stepwise AF ablation (AFA) using a closed-irrigation ablation catheter. Recurrence of AF was monitored and outcomes were evaluated using Kaplan-Meier survival analysis and Cox proportional hazards models. Mean age was 59.0 years, 74.9% were male, 56.4% of patients were paroxysmal and mean duration of AF was 5.4 years. Patients had multiple comorbidities including hypertension (76.4%), tobacco abuse (42.1%), diabetes (17.4%), and obesity (mean body mass index 30.8). The median follow-up was 55.8 weeks. Overall event-free survival was 73.6% with one ablation and 77.4% after reablation (reablation rate was 8.7%). Median time to recurrence was 26.9 weeks. AF was more likely to recur in patients being treated with antiarrhythmic therapy at the time of last follow-up (recurrence rate 30.3% with antiarrhythmic drugs, 13.2% without antiarrhythmic drugs; hazard ratio [HR] 2.2, 95% confidence interval [CI] 1.1-4.4, P = 0.024) and in those with a history of AF greater than 2 years duration (HR 2.7, 95% CI 1.1-6.9, P = 0.038). Our study represents the largest cohort of patients receiving AFA with closed-irrigation ablation catheters. We demonstrate comparable outcomes to those previously reported in studies of open-irrigation ablation catheters. Given the theoretical benefits of a closed-irrigation system, a large head-to-head comparison using this catheter is warranted. ©2012, The Authors. Journal compilation ©2012 Wiley Periodicals, Inc.

Interatrial septum thickness and difficulty with transseptal puncture during redo catheter ablation of atrial fibrillation.

Science.gov (United States)

Tomlinson, David R; Sabharwal, Nikant; Bashir, Yaver; Betts, Timothy R

2008-12-01

Patients undergoing catheter ablation for atrial fibrillation (AF) frequently require redo procedures, but there are no data reporting interatrial septum thickness (IAS) and difficulty during repeat transseptal puncture (TSP). Patients undergoing two separate AF ablation procedures had preprocedural fossa ovalis (FO) thickness measured using transesophageal echocardiography (TEE). "Difficult" TSP was defined by two observers as requiring excessive force, or conversion to TEE guidance. The study comprised 42 patients (37 male) with mean+/-SD age 55+/-9 years. Mean FO thickness was significantly greater at the time of redo TSP (2.2+/-1.6 mm vs 2.6+/-1.5 mm at redo, P=0.03); however, this finding was limited to those who underwent initial dual transseptal sheath procedures, FO thickness 2.0+/-1.5 mm and 2.5+/-1.4 mm for TEE 1 and 2, respectively (P=0.048). There was a trend for more frequent difficult redo TSP procedures, 7/42 (17%; 95% confidence interval [CI] 8-31) redo, versus 4/42 (10%; 95% CI 3-23) first TSP. On univariate analysis, FO thickness was not predictive of TSP difficulty; the only predictor of difficult redo TSP was diabetes. IAS thickness at the FO increased following catheter ablation of AF, yet on subgroup analysis this was limited to initial procedures utilizing dual transseptal sheaths. There was a trend toward more frequent difficulty during redo TSP, yet this was not associated with FO thickening. Diabetes may predispose to difficulty during redo TSP; this finding requires confirmation in a larger study population.

Percutaneous laser ablation of hepatocellular carcinoma in patients with liver cirrhosis awaiting liver transplantation

International Nuclear Information System (INIS)

Pompili, Maurizio; Pacella, Claudio Maurizio; Francica, Giampiero; Angelico, Mario; Tisone, Giuseppe; Craboledda, Paolo; Nicolardi, Erica; Rapaccini, Gian Ludovico; Gasbarrini, Giovanni

2010-01-01

Objective: The aim of this study was to determine the effectiveness and safety of percutaneous laser ablation for the treatment of cirrhotic patients with hepatocellular carcinoma awaiting liver transplantation. Materials and methods: The data of 9 male cirrhotic patients (mean age 50 years, range 45-60 years) with 12 biopsy proven nodules of hepatocellular carcinoma (mean diameter 2.0 cm, range 1.0-3.0 cm) treated by laser ablation before liver transplantation between June 2000 and January 2006 were retrospectively reviewed. Laser ablation was carried out by inserting 300 nm optical fibers through 21-Gauge needles (from two to four) positioned under ultrasound guidance into the target lesions. A continuous wave Neodymium:Yttrium Aluminium Garnet laser was used. Transarterial chemoembolization prior to liver transplantation was performed in two incompletely ablated tumors. Results: No procedure-related major complications were recorded. During the waiting time to liver transplantation local tumor progression after ablation occurred in 3 nodules (25%). At histological examination of the explanted livers complete necrosis was found in 8 nodules (66.7%, all treated exclusively with laser ablation), partial necrosis >50% in 3 nodules (25%), and partial necrosis <50% in 1 nodule. Conclusion: In patients with cirrhotic livers awaiting liver transplantation, percutaneous laser ablation is safe and effective for the management of small hepatocellular carcinoma.

Loss of pace capture on the ablation line: a new marker for complete radiofrequency lesions to achieve pulmonary vein isolation.

Science.gov (United States)

Steven, Daniel; Reddy, Vivek Y; Inada, Keiichi; Roberts-Thomson, Kurt C; Seiler, Jens; Stevenson, William G; Michaud, Gregory F

2010-03-01

Catheter ablation procedures for atrial fibrillation (AF) often involve circumferential antral isolation of pulmonary veins (PV). Inability to reliably identify conduction gaps on the ablation line necessitates placing additional lesions within the intended lesion set. This pilot study investigated the relationship between loss of pace capture directly along the ablation line and electrogram criteria for PV isolation (PVI). Using a 3-dimensional anatomic mapping system and irrigated-tip radiofrequency (RF) ablation catheter, lesions were placed in the PV antra to encircle ipsilateral vein pairs until pace capture at 10 mA/2 ms no longer occurred along the line. During ablation, a circular mapping catheter was placed in an ipsilateral PV, but the electrograms were not revealed until loss-of-pace capture. The procedural end point was PVI (entrance and exit block). Thirty patients (57 +/- 12 years; 15 male [50%]) undergoing PVI in 2 centers (3 primary operators) were included (left atrial diameter 40 +/- 4 mm, left ventricular ejection fraction 60 +/- 7%). All patients reached the end points of complete PVI and loss of pace capture. When PV electrograms were revealed after loss of pace capture along the line, PVI was present in 57 of 60 (95%) vein pairs. In the remaining 3 of 60 (5%) PV pairs, further RF applications achieved PVI. The procedure duration was 237 +/- 46 minutes, with a fluoroscopy time of 23 +/- 9 minutes. Analysis of the blinded PV electrograms revealed that even after PVI was achieved, additional sites of pace capture were present on the ablation line in 30 of 60 (50%) of the PV pairs; 10 +/- 4 additional RF lesions were necessary to fully achieve loss of pace capture. After ablation, the electrogram amplitude was lower at unexcitable sites (0.25 +/- 0.15 mV vs. 0.42 +/- 0.32 mV, P capture sites, suggesting that electrogram amplitude lacks specificity for identifying pace capture sites. Complete loss of pace capture directly along the circumferential

Percutaneous radiofrequency ablation of spleen for the treatment of hypersplenism

International Nuclear Information System (INIS)

Wu Yuxuan; Zhang Yanfang; Zheng Xuefen; Zhang Yuanhua; Kong Jian; Shen Xinying; Dou Yongchong

2009-01-01

Objective: To summarize the clinical effect and experience of CT-guided radiofrequency ablation (RFA) of spleen by using cool-tip electrodes in the treatment of hypersplenism in patients with liver cirrhosis and portal hypertension. Methods: CT-guided RFA of spleen by using cool-tip electrodes was performed in 15 patients with hypersplenism associated with liver cirrhosis and portal hypertension. The routine blood count was studied both before and after the procedure. Enhanced CT or MR scanning was reexamined after the treatment to determine the ablated volume of the spleen. The results were statistically analyzed. Results: The ablated volume of the spleen accounted for (31.0 ± 4.6)% of the whole spleen. Before the treatment the platelet count was (62 ± 9.8) x 10 9 /L. One month after the treatment, the platelet count was increased to (96 ± 11) x 10 9 /L, which was significantly higher than that before the treatment (P<0.05). One patient developed portal thrombosis four months after RFA, and no other serious complications occurred. Conclusion: CT-guided radiofrequency ablation of spleen by using cool-tip electrodes is an effective and safe treatment for hypersplenism in patients with liver cirrhosis and portal hypertension. (authors)

Nursing care for patients with pulmonary malignancy after radiofrequency ablation therapy

International Nuclear Information System (INIS)

Ren Caifeng; Gong Yunzhen; Li Huiqian; Ge Lei; Zhao Fang

2009-01-01

Objective: To discuss the nursing care strategy for patients with pulmonary malignancy who were treated with CT-guided radiofrequency ablation (RFA) therapy. Methods CT-guided RFA was performed in 21 patients with pulmonary malignancy, the sum total of ablated lesions was 31. Results: RFA procedure was successfully accomplished in all patients. The operation-related complications included minor pneumothorax, hydropneumothorax, bloody sputum, pain and mild fever. The clinical symptoms were soon relieved after medication according to indications. No death or serious complications occurred. Conclusion: For patients with pulmonary malignancy who were treated with CT-guided RFA, esponsible nursing care and serious, careful observation after operation are very helpful for patient's recovery. (authors)

Food restriction affects Y-maze spatial recognition memory in developing mice.

Science.gov (United States)

Fu, Yu; Chen, Yanmei; Li, Liane; Wang, Yumei; Kong, Xiangyang; Wang, Jianhong

2017-08-01

The ambiguous effects of food restriction (FR) on cognition in rodents have been mostly explored in the aged brain by a variety of paradigms, in which either rewards or punishments are involved. This study aims to examine the effects of chronic and acute FR with varying intensities on spatial recognition memory in developing mice. We have used a Y-maze task that is based on the innate tendency of rodents to explore novel environments. In chronic FR, mice had 70-30% chow of control for seven weeks. In acute FR, mice were food restricted for 12-48h before the tests. We found that chronic FR had no effect on the preference of mice for novelty in the Y-maze, but severe FR (50-30% of control) caused impairment on spatial recognition memory. The impairment significantly correlated with the slow weight growth induced by FR. Acute FR also did not affect the novelty preference of mice, but either improved or impaired the memory retention. These data suggest chronic FR impairs Y-maze spatial recognition memory in developing mice depending on FR intensity and individual tolerability of the FR. Moreover, acute FR exerts diverse effects on the memory, either positive or negative. Our findings have revealed new insights on the effects of FR on spatial recognition memory in developing animals. Copyright © 2017 ISDN. Published by Elsevier Ltd. All rights reserved.

Radiofrequency ablation of pulmonary tumors

Energy Technology Data Exchange (ETDEWEB)

Crocetti, Laura, E-mail: l.crocetti@med.unipi.i [Division of Diagnostic Imaging and Intervention, Department of Liver Transplants, Hepatology and Infectious Diseases, Pisa University School of Medicine (Italy); Lencioni, Riccardo [Division of Diagnostic Imaging and Intervention, Department of Liver Transplants, Hepatology and Infectious Diseases, Pisa University School of Medicine (Italy)

2010-07-15

The development of image-guided percutaneous techniques for local tumor ablation has been one of the major advances in the treatment of solid tumors. Among these methods, radiofrequency (RF) ablation is currently established as the primary ablative modality at most institutions. RF ablation is accepted as the best therapeutic choice for patients with early-stage hepatocellular carcinoma when liver transplantation or surgical resection are not suitable options and is considered as a viable alternate to surgery for inoperable patients with limited hepatic metastatic disease, especially from colorectal cancer. Recently, RF ablation has been demonstrated to be a safe and valuable treatment option for patients with unresectable or medically inoperable lung malignancies. Resection should remain the standard therapy for non-small cell lung cancer (NSCLC) but RF ablation may be better than conventional external-beam radiation for the treatment of the high-risk individual with NSCLC. Initial favourable outcomes encourage combining radiotherapy and RF ablation, especially for treating larger tumors. In the setting of colorectal cancer lung metastases, survival rates provided by RF ablation in selected patients, are substantially higher than those obtained with any chemotherapy regimens and provide indirect evidence that RF ablation therapy improves survival in patients with limited lung metastatic disease.

Use of an eight-arm radial water maze to assess working and reference memory following neonatal brain injury.

Science.gov (United States)

Penley, Stephanie C; Gaudet, Cynthia M; Threlkeld, Steven W

2013-12-04

Working and reference memory are commonly assessed using the land based radial arm maze. However, this paradigm requires pretraining, food deprivation, and may introduce scent cue confounds. The eight-arm radial water maze is designed to evaluate reference and working memory performance simultaneously by requiring subjects to use extra-maze cues to locate escape platforms and remedies the limitations observed in land based radial arm maze designs. Specifically, subjects are required to avoid the arms previously used for escape during each testing day (working memory) as well as avoid the fixed arms, which never contain escape platforms (reference memory). Re-entries into arms that have already been used for escape during a testing session (and thus the escape platform has been removed) and re-entries into reference memory arms are indicative of working memory deficits. Alternatively, first entries into reference memory arms are indicative of reference memory deficits. We used this maze to compare performance of rats with neonatal brain injury and sham controls following induction of hypoxia-ischemia and show significant deficits in both working and reference memory after eleven days of testing. This protocol could be easily modified to examine many other models of learning impairment.

Ultrasound-guided percutaneous radiofrequency ablation of liver tumors: How we do it safety and completely

Energy Technology Data Exchange (ETDEWEB)

Kim, Jin Woong; Shin, Sang Soo; Heo, Suk Hee; Hong, Jun Hyung; Lim, Hyo Soon; Seon, Hyun Ju; Hur, Young Hoe; Park, Chang Hwan; Jeong, Yong Yeon; Kang, Heoung Keun [Chonnam National University Medical School, Gwangju (Korea, Republic of)

2015-12-15

Ultrasound-guided percutaneous radiofrequency (RF) ablation has become one of the most promising local cancer therapies for both resectable and nonresectable hepatic tumors. Although RF ablation is a safe and effective technique for the treatment of liver tumors, the outcome of treatment can be closely related to the location and shape of the tumors. There may be difficulties with RF ablation of tumors that are adjacent to large vessels or extrahepatic heat-vulnerable organs and tumors in the caudate lobe, possibly resulting in major complications or treatment failure. Thus, a number of strategies have been developed to overcome these challenges, which include artificial ascites, needle track ablation, fusion imaging guidance, parallel targeting, bypass targeting, etc. Operators need to use the right strategy in the right situation to avoid the possibility of complications and incomplete thermal tissue destruction; with the right strategy, RF ablation can be performed successfully, even for hepatic tumors in high-risk locations. This article offers technical strategies that can be used to effectively perform RF ablation as well as to minimize possible complications related to the procedure with representative cases and schematic illustrations.

Ablative skin resurfacing.

Science.gov (United States)

Agrawal, Nidhi; Smith, Greg; Heffelfinger, Ryan

2014-02-01

Ablative laser resurfacing has evolved as a safe and effective treatment for skin rejuvenation. Although traditional lasers were associated with significant thermal damage and lengthy recovery, advances in laser technology have improved safety profiles and reduced social downtime. CO2 lasers remain the gold standard of treatment, and fractional ablative devices capable of achieving remarkable clinical improvement with fewer side effects and shorter recovery times have made it a more practical option for patients. Although ablative resurfacing has become safer, careful patient selection and choice of suitable laser parameters are essential to minimize complications and optimize outcomes. This article describes the current modalities used in ablative laser skin resurfacing and examines their efficacy, indications, and possible side effects. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Diaphragmatic Hernia After Radiofrequency Ablation for Hepatocellular Carcinoma

International Nuclear Information System (INIS)

Yamagami, Takuji; Yoshimatsu, Rika; Matsushima, Shigenori; Tanaka, Osamu; Miura, Hiroshi; Nishimura, Tsunehiko

2011-01-01

We describe a 71-year-old woman with a hepatocellular carcinoma who underwent percutaneous radiofrequency ablation (RF) with a single internally cooled electrode under computed tomography (CT) fluoroscopic guidance. Nine months after the procedure, CT images showed herniation of the large intestine into the right pleural cavity. To our knowledge this complication of RF performed with a single internally cooled electrode under CT guidance has not been previously reported.

Picosecond laser ablation of porcine sclera

Science.gov (United States)

Góra, Wojciech S.; Harvey, Eleanor M.; Dhillon, Baljean; Parson, Simon H.; Maier, Robert R. J.; Hand, Duncan P.; Shephard, Jonathan D.

2013-03-01

Lasers have been shown to be successful in certain medical procedures and they have been identified as potentially making a major contribution to the development of minimally invasive procedures. However, the uptake is not as widespread and there is scope for many other applications where laser devices may offer a significant advantage in comparison to the traditional surgical tools. The purpose of this research is to assess the potential of using a picosecond laser for minimally invasive laser sclerostomy. Experiments were carried out on porcine scleral samples due to the comparable properties to human tissue. Samples were prepared with a 5mm diameter trephine and were stored in lactated Ringer's solution. After laser machining, the samples were fixed in 3% glutaraldehyde, then dried and investigated under SEM. The laser used in the experiments is an industrial picosecond TRUMPF TruMicro laser operating at a wavelength of 1030nm, pulse length of 6ps, repetition rate of 1 kHz and a focused spot diameter of 30μm. The laser beam was scanned across the samples with the use of a galvanometer scan head and various ablation patterns were investigated. Processing parameters (pulse energy, spot and line separation) which allow for the most efficient laser ablation of scleral tissue without introducing any collateral damage were investigated. The potential to create various shapes, such as linear incisions, square cavities and circular cavities was demonstrated.

Plasma-mediated radiofrequency ablation followed by percutaneous cementoplasty under fluoro-CT guidance: a case report

OpenAIRE

Carrafiello, Gianpaolo; Lagan?, Domenico; Ianniello, Andrea; Fontana, Federico; Mangini, Monica; Mocciardini, Lucia; Span?, Emanuela; Piacentino, Filippo; Cuffari, Salvatore; Fugazzola, Carlo

2009-01-01

We report a case of a 81-year-old Caucasian man with colorectal carcinoma, treated by surgery in 1998, referred for palliative treatment of a refractory painful caused by osteolytic metastases of 2.5 cm in back-upper ilium spine. Plasma-mediated radiofrequency ablation was performed under conscious sedation, using Fluoroscopic Computer Tomography guidance. After completing the ablation phase of the procedure, a mixture of bone cement and Biotrace sterile barium sulfate was injected into the a...

Left atrial and left ventricular diastolic function after the maze procedure for atrial fibrillation in mitral valve disease: degenerative versus rheumatic.

Science.gov (United States)

Kim, Hwan Wook; Moon, Mi Hyoung; Jo, Keon Hyun; Song, Hyun; Lee, Jae Won

2015-02-01

The present study was aimed to compare the left atrial and left ventricular diastolic functions amongst the rheumatic and degenerative mitral valve disease patients in atrial fibrillation who reverted to normal sinus rhythm following Cox-maze procedure. We prospectively investigated the left atrial and left ventricular function with Doppler echocardiography, by dividing into the rheumatic (N = 105) and the degenerative group (N = 47). Over the follow-up period (mean: 4.4 ± 1.2 years in the rheumatic group, 4.8 ± 1.3 years in the degenerative group), the rheumatic group showed statistically significant decrease in A' velocity and E' velocity, on contrary to degenerative group (A' velocity: mean decrease of 0.43 ± 0.13 cm/s in the rheumatic group, mean increase of 0.57 ± 0.11 cm/s in the degenerative group, p = 0.029, E' velocity: mean decrease of 0.23 ± 0.17 cm/s in the rheumatic group, mean increase of 0.21 ± 0.15 cm/s in the degenerative group, p = 0.031). In addition, the rheumatic group showed statistically significant increase in E/E' ratio than the degenerative group (mean increase of 4.49 ± 1.98 in the rheumatic group, mean increase of 1.74 ± 1.52 in the degenerative group, p = 0.047). Despite successful sinus rhythm restoration, the progressive loss of LA function as well as LV diastolic function is more prominent in the rheumatic group than the degenerative group. Therefore, differentiated strategies for postoperative surveillance are needed according to the pathology of mitral valve disease.

Real-time circumferential mapping catheter tracking for motion compensation in atrial fibrillation ablation procedures

Science.gov (United States)

Brost, Alexander; Bourier, Felix; Wimmer, Andreas; Koch, Martin; Kiraly, Atilla; Liao, Rui; Kurzidim, Klaus; Hornegger, Joachim; Strobel, Norbert

2012-02-01

Atrial fibrillation (AFib) has been identified as a major cause of stroke. Radiofrequency catheter ablation has become an increasingly important treatment option, especially when drug therapy fails. Navigation under X-ray can be enhanced by using augmented fluoroscopy. It renders overlay images from pre-operative 3-D data sets which are then fused with X-ray images to provide more details about the underlying soft-tissue anatomy. Unfortunately, these fluoroscopic overlay images are compromised by respiratory and cardiac motion. Various methods to deal with motion have been proposed. To meet clinical demands, they have to be fast. Methods providing a processing frame rate of 3 frames-per-second (fps) are considered suitable for interventional electrophysiology catheter procedures if an acquisition frame rate of 2 fps is used. Unfortunately, when working at a processing rate of 3 fps, the delay until the actual motion compensated image can be displayed is about 300 ms. More recent algorithms can achieve frame rates of up to 20 fps, which reduces the lag to 50 ms. By using a novel approach involving a 3-D catheter model, catheter segmentation and a distance transform, we can speed up motion compensation to 25 fps which results in a display delay of only 40 ms on a standard workstation for medical applications. Our method uses a constrained 2-D/3-D registration to perform catheter tracking, and it obtained a 2-D tracking error of 0.61 mm.

Radiofrequency ablation of neuroendocrine liver metastases: the Middlesex experience.

Science.gov (United States)

Gillams, A; Cassoni, A; Conway, G; Lees, W

2005-01-01

Current treatment options for neuroendocrine liver metastases are not widely applicable or not that effective. Image-guided thermal ablation offers the possibility of a minimally invasive, albeit palliative, treatment that decreases tumor volume, preserves most of the normal liver, and can be repeated several times. We report our experience with image-guided thermal ablation in 25 patients with unresectable liver metastases. Since 1990 we have treated 189 tumors at 66 treatment sessions in 25 patients (12 female, 13 male; median age, 56 years; age range, 26--78 years). Thirty treatments were performed with a solid-state laser, and 36 treatments were performed with radiofrequency ablation. All but one treatment was performed percutaneously under image guidance. Sixteen patients had metastases from carcinoid primaries, three from gastrinoma, two from insulinoma, and four from miscellaneous causes. Fourteen of 25 had symptoms from hormone secretion. Imaging follow-up was available in 19 patients at a median of 21 months (range, 4--75 months). There was a complete response in six patients, a partial response in seven, and stable disease in one; hence, tumor load was controlled in 14 of 19 patients (74%). Relief of hormone-related symptoms was achieved in nine of 14 patients (69%). The median survival period from the diagnosis of liver metastases was 53 months. One patient with end-stage cardiac disease died after a carcinoid crisis. There were eight (12%) complications: five local and three distant, four major and four minor. As a minimally invasive, readily repeatable procedure that can be used to ablate small tumors, preferably before patients become severely symptomatic, radiofrequency ablation can provide effective control of liver tumor volume in most patients over many years.

The safety and efficacy of irreversible electroporation for the ablation of prostate cancer: a multicentre prospective human in vivo pilot study protocol

NARCIS (Netherlands)

van den Bos, W.; de Bruin, D. M.; Muller, B. G.; Varkarakis, I. M.; Karagiannis, A. A.; Zondervan, P. J.; Laguna Pes, M. P.; Veelo, D. P.; Savci Heijink, C. D.; Engelbrecht, M. R. W.; Wijkstra, H.; de Reijke, T. M.; de la Rosette, J. J. M. C. H.

2014-01-01

Current surgical and ablative treatment options for prostate cancer have a relatively high incidence of side effects, which may diminish the quality of life. The side effects are a consequence of procedure-related damage of the blood vessels, bowel, urethra or neurovascular bundle. Ablation with

Transcervical, intrauterine ultrasound-guided radiofrequency ablation of uterine fibroids with the VizAblate® System: three- and six-month endpoint results from the FAST-EU study.

Science.gov (United States)

Bongers, Marlies; Brölmann, Hans; Gupta, Janesh; Garza-Leal, José Gerardo; Toub, David

This was a prospective, longitudinal, multicenter, single-arm controlled trial, using independent core laboratory validation of MRI results, to establish the effectiveness and confirm the safety of the VizAblate® System in the treatment of symptomatic uterine fibroids. The VizAblate System is a transcervical device that ablates fibroids with radiofrequency energy, guided by a built-in intrauterine ultrasound probe. Fifty consecutive women with symptomatic uterine fibroids received treatment with the VizAblate System. Patients had a minimum Menstrual Pictogram score of 120, no desire for fertility, and met additional inclusion and exclusion criteria. The VizAblate System was inserted transcervically and individual fibroids were ablated with radiofrequency energy. An integrated intrauterine ultrasound probe was used for fibroid imaging and targeting. Anesthesia was at the discretion of each investigator. The primary study endpoint was the percentage change in perfused fibroid volume, as assessed by contrast-enhanced MRI at 3 months. Secondary endpoints, reached at 6 months, included safety, percentage reductions in the Menstrual Pictogram (MP) score and the Symptom Severity Score (SSS) subscale of the Uterine Fibroid Symptom-Quality of Life questionnaire (UFS-QOL), along with the rate of surgical reintervention for abnormal uterine bleeding and the mean number of days to return to normal activity. Additional assessments included the Health-Related Quality of Life (HRQOL) subscale of the UFS-QOL, medical reintervention for abnormal uterine bleeding, and procedure times. Fifty patients were treated, representing 92 fibroids. Perfused fibroid volumes were reduced at 3 months by an average of 68.8 ± 27.8 % ( P  abnormal uterine bleeding associated with fibroids, with appropriate safety and a low reintervention rate.

Fast and automatic depth control of iterative bone ablation based on optical coherence tomography data

Science.gov (United States)

Fuchs, Alexander; Pengel, Steffen; Bergmeier, Jan; Kahrs, Lüder A.; Ortmaier, Tobias

2015-07-01

Laser surgery is an established clinical procedure in dental applications, soft tissue ablation, and ophthalmology. The presented experimental set-up for closed-loop control of laser bone ablation addresses a feedback system and enables safe ablation towards anatomical structures that usually would have high risk of damage. This study is based on combined working volumes of optical coherence tomography (OCT) and Er:YAG cutting laser. High level of automation in fast image data processing and tissue treatment enables reproducible results and shortens the time in the operating room. For registration of the two coordinate systems a cross-like incision is ablated with the Er:YAG laser and segmented with OCT in three distances. The resulting Er:YAG coordinate system is reconstructed. A parameter list defines multiple sets of laser parameters including discrete and specific ablation rates as ablation model. The control algorithm uses this model to plan corrective laser paths for each set of laser parameters and dynamically adapts the distance of the laser focus. With this iterative control cycle consisting of image processing, path planning, ablation, and moistening of tissue the target geometry and desired depth are approximated until no further corrective laser paths can be set. The achieved depth stays within the tolerances of the parameter set with the smallest ablation rate. Specimen trials with fresh porcine bone have been conducted to prove the functionality of the developed concept. Flat bottom surfaces and sharp edges of the outline without visual signs of thermal damage verify the feasibility of automated, OCT controlled laser bone ablation with minimal process time.

A new catheter design for combined radiofrequency ablation and optoacoustic treatment monitoring using copper-coated light-guides

Science.gov (United States)

Rebling, Johannes; Oyaga Landa, Francisco Javier; Deán-Ben, Xosé Luis; Razansky, Daniel

2018-02-01

Electrosurgery, i.e. the application of radiofrequency current for tissue ablation, is a frequently used treatment for many cardiac arrhythmias. Electrophysiological and anatomic mapping, as well as careful radiofrequency power control typically guide the radiofrequency ablation procedure. Despite its widespread application, accurate monitoring of the lesion formation with sufficient spatio-temporal resolution remains challenging with the existing imaging techniques. We present a novel integrated catheter for simultaneous radiofrequency ablation and optoacoustic monitoring of the lesion formation in real time and 3D. The design combines the delivery of both electric current and optoacoustic excitation beam in a single catheter consisting of copper-coated multimode light-guides and its manufacturing is described in detail. The electrical current causes coagulation and desiccation while the excitation light is locally absorbed, generating OA responses from the entire treated volume. The combined ablation-monitoring capabilities were verified using ex-vivo bovine tissue. The formed ablation lesions showed a homogenous coagulation while the ablation was monitored in realtime with a volumetric frame rate of 10 Hz over 150 seconds.

1.0 T open-configuration magnetic resonance-guided microwave ablation of pig livers in real time

Science.gov (United States)

Dong, Jun; Zhang, Liang; Li, Wang; Mao, Siyue; Wang, Yiqi; Wang, Deling; Shen, Lujun; Dong, Annan; Wu, Peihong

2015-01-01

The current fastest frame rate of each single image slice in MR-guided ablation is 1.3 seconds, which means delayed imaging for human at an average reaction time: 0.33 seconds. The delayed imaging greatly limits the accuracy of puncture and ablation, and results in puncture injury or incomplete ablation. To overcome delayed imaging and obtain real-time imaging, the study was performed using a 1.0-T whole-body open configuration MR scanner in the livers of 10 Wuzhishan pigs. A respiratory-triggered liver matrix array was explored to guide and monitor microwave ablation in real-time. We successfully performed the entire ablation procedure under MR real-time guidance at 0.202 s, the fastest frame rate for each single image slice. The puncture time ranged from 23 min to 3 min. For the pigs, the mean puncture time was shorted to 4.75 minutes and the mean ablation time was 11.25 minutes at power 70 W. The mean length and widths were 4.62 ± 0.24 cm and 2.64 ± 0.13 cm, respectively. No complications or ablation related deaths during or after ablation were observed. In the current study, MR is able to guide microwave ablation like ultrasound in real-time guidance showing great potential for the treatment of liver tumors. PMID:26315365

Anxiolytic effect of clonazepam in female rats: grooming microstructure and elevated plus maze tests.

Science.gov (United States)

Nin, Maurício S; Couto-Pereira, Natividade S; Souza, Marilise F; Azeredo, Lucas A; Ferri, Marcelo K; Dalprá, Walesca L; Gomez, Rosane; Barros, Helena M T

2012-06-05

Grooming behavior is an adaptation to a stressful environment that can vary in accordance with stress intensity. Direct and indirect GABA(A) receptor agonists decrease duration, frequency, incorrect transitions and uninterrupted bouts of grooming. Hormonal variation during the different phases of the estrous cycle of female rats also changes the grooming behavior. It is known that GABA(A) agonists and endogenous hormones change anxiety-like behaviors observed in the elevated plus maze test, a classical animal model of anxiety. This study was designed to determine the anxiolytic effect of clonazepam in female rats in different estrous phases and to correlate anxiety behaviors in the elevated plus maze and grooming microstructure tests. Our results show that female rats displayed higher anxiety-like behavior scores during the estrus and proestrus phases in the elevated plus maze and that clonazepam (0.25 mg/kg; i.p.) had an anxiolytic effect that was independent of the estrous phase. Grooming behaviors were higher in the proestrus phase but were decreased by clonazepam administration, independent of the estrous phase, demonstrating the anxiolytic effect of this drug in both animal models. Grooming behaviors were moderately associated with anxiolytic-like behaviors in the elevated plus maze test. Here, we describe the anxiolytic effect of clonazepam and the influence of estrous phase on anxiety. Moreover, we show that the grooming microstructure test is a useful tool for detecting anxiolytic-like behaviors in rats. Copyright © 2012 Elsevier B.V. All rights reserved.

Clinical application of early PET-CT imaging after radiofrequency ablation of liver neoplasms

International Nuclear Information System (INIS)

Liu Zhaoyu; Chang Zhihui; Lu Zaiming; Xin Jun; Wang Xiaoming; Guo Qiyong

2009-01-01

Objective: To evaluate the application of early 18 F-FDG PET-CT imaging after radiofrequency ablation (RFA) of hepatic malignancies. Methods: Fifteen patients with liver tumors (five hepatocellular carcinoma, ten colorectal cancer liver metastasis) underwent RFA as part of clinical management. The lesions were all hypermetabolic on PET-CT performed within 2 weeks prior to RFA. All subjects underwent 18 F-FDG PET-CT (early PET-CT) within 24 hours after RFA. Total photopenia, focal uptake, and rim-shaped uptake were regarded as complete ablation, residual tumor, and inflammation, respectively. Follow-up PET-CT scans were performed as the reference standard. Results: Twelve patients showed total photopenia at the ablation site on the early PET-CT scan, and in all of these patients, total photopenia at the ablation sites was seen on the follow-up PET-CT scans. Two patients had focal uptake at the ablation sites on the early PET-CT scan, and both of these foci increased in size and intensity, which were compatible with residual tumors at the time of ablation. Only one patient had rim-shaped uptake on the early PET-CT scan. The rim-shaped uptake disappeared on PET-CT performed 3 months later, which indicated the nature of inflammation. Conclusions: There is infrequent inflammatory uptake at the RFA site of liver tumors on 18 F-FDG PET-CT if scanning is performed within 24 hours after ablation. Thus, early PET- CT has the potential to evaluate the efficacy of an RFA procedure by indicating tumor-free as total photopenia and residual tumors as focal uptake. (authors)

Ablation of fast-spiking interneurons in the dorsal striatum, recapitulating abnormalities seen post-mortem in Tourette syndrome, produces anxiety and elevated grooming.

Science.gov (United States)

Xu, M; Li, L; Pittenger, C

2016-06-02

Tic disorders, including Tourette syndrome (TS), are thought to involve pathology of cortico-basal ganglia loops, but their pathology is not well understood. Post-mortem studies have shown a reduced number of several populations of striatal interneurons, including the parvalbumin-expressing fast-spiking interneurons (FSIs), in individuals with severe, refractory TS. We tested the causal role of this interneuronal deficit by recapitulating it in an otherwise normal adult mouse using a combination transgenic-viral cell ablation approach. FSIs were reduced bilaterally by ∼40%, paralleling the deficit found post-mortem. This did not produce spontaneous stereotypies or tic-like movements, but there was increased stereotypic grooming after acute stress in two validated paradigms. Stereotypy after amphetamine, in contrast, was not elevated. FSI ablation also led to increased anxiety-like behavior in the elevated plus maze, but not to alterations in motor learning on the rotorod or to alterations in prepulse inhibition, a measure of sensorimotor gating. These findings indicate that a striatal FSI deficit can produce stress-triggered repetitive movements and anxiety. These repetitive movements may recapitulate aspects of the pathophysiology of tic disorders. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

Image-guided Tumor Ablation: Standardization of Terminology and Reporting Criteria—A 10-Year Update

Science.gov (United States)

Solbiati, Luigi; Brace, Christopher L.; Breen, David J.; Callstrom, Matthew R.; Charboneau, J. William; Chen, Min-Hua; Choi, Byung Ihn; de Baère, Thierry; Dodd, Gerald D.; Dupuy, Damian E.; Gervais, Debra A.; Gianfelice, David; Gillams, Alice R.; Lee, Fred T.; Leen, Edward; Lencioni, Riccardo; Littrup, Peter J.; Livraghi, Tito; Lu, David S.; McGahan, John P.; Meloni, Maria Franca; Nikolic, Boris; Pereira, Philippe L.; Liang, Ping; Rhim, Hyunchul; Rose, Steven C.; Salem, Riad; Sofocleous, Constantinos T.; Solomon, Stephen B.; Soulen, Michael C.; Tanaka, Masatoshi; Vogl, Thomas J.; Wood, Bradford J.; Goldberg, S. Nahum

2014-01-01

Image-guided tumor ablation has become a well-established hallmark of local cancer therapy. The breadth of options available in this growing field increases the need for standardization of terminology and reporting criteria to facilitate effective communication of ideas and appropriate comparison among treatments that use different technologies, such as chemical (eg, ethanol or acetic acid) ablation, thermal therapies (eg, radiofrequency, laser, microwave, focused ultrasound, and cryoablation) and newer ablative modalities such as irreversible electroporation. This updated consensus document provides a framework that will facilitate the clearest communication among investigators regarding ablative technologies. An appropriate vehicle is proposed for reporting the various aspects of image-guided ablation therapy including classification of therapies, procedure terms, descriptors of imaging guidance, and terminology for imaging and pathologic findings. Methods are addressed for standardizing reporting of technique, follow-up, complications, and clinical results. As noted in the original document from 2003, adherence to the recommendations will improve the precision of communications in this field, leading to more accurate comparison of technologies and results, and ultimately to improved patient outcomes. © RSNA, 2014 Online supplemental material is available for this article. PMID:24927329

Radiofrequency ablation of atrial tachyarrhythmias in adults with tetralogy of Fallot - predictors of success and outcome.

Science.gov (United States)

Ezzat, Vivienne A; Ryan, Matthew J; O'Leary, Justin; Ariti, Cono; Deanfield, John; Pandya, Bejal; Cullen, Shay; Walker, Fiona; Khan, Fakhar; Abrams, Dominic J; Lambiase, Pier D; Lowe, Martin D

2017-03-01

Adults with tetralogy of Fallot experience atrial tachyarrhythmias; however, there are a few data on the outcomes of radiofrequency ablation. We examined the characteristics, outcome, and predictors of recurrence of atrial tachyarrhythmias after radiofrequency ablation in tetralogy of Fallot patients. Methods/results Retrospective data were collected from 2004 to 2013. In total, 56 ablations were performed on 37 patients. We identified two matched controls per case: patients with tetralogy of Fallot but no radiofrequency ablation and not known to have atrial tachyarrhythmias. Acute success was 98%. Left atrial arrhythmias increased in frequency over time. The mean follow-up was 41 months; 78% were arrhythmia-free. Number of cardiac surgeries, age, and presence of atrial fibrillation were predictors of recurrence. Lone cavo-tricuspid isthmus-dependent flutter reduced the likelihood of atrial fibrillation. Right and left atria in patients with tetralogy of Fallot were larger in ablated cases than controls. NYHA class was worse in cases and improved after ablation; baseline status predicted death. Of matched non-ablated controls, a number of them had atrial fibrillation. These patients were excluded from the case-control study but analysed separately. Most of them had died during follow-up, whereas of the matched ablated cases all were alive and the majority in sinus rhythm. Patients with tetralogy of Fallot and atrial tachyarrhythmias have more dilated atria than those without atrial tachyarrhythmias. Radiofrequency ablation improves functional status. Left atrial ablation is more commonly required with repeat procedures. There is a high prevalence of atrial tachyarrhythmias, particularly atrial fibrillation, in patients with tetralogy of Fallot; early radiofrequency ablation may have a protective effect against this.

Safety profile of multielectrode-phased radiofrequency pulmonary vein ablation catheter and irrigated radiofrequency catheter.

Science.gov (United States)

Wasmer, K; Foraita, P; Leitz, P; Güner, F; Pott, C; Lange, P S; Eckardt, L; Mönnig, G

2016-01-01

Silent cerebral lesions with the multielectrode-phased radiofrequency (RF) pulmonary vein ablation catheter (PVAC(®)) have recently been investigated. However, comparative data on safety in relation to irrigated RF ablation are missing. One hundred and fifty consecutive patients (58 ± 12 years, 56 female) underwent first pulmonary vein isolation (PVI) for atrial fibrillation (61% paroxysmal) using PVAC(®) (PVAC). Procedure data as well as in-hospital complications were compared with 300 matched patients who underwent PVI using irrigated RF (iRF). Procedure duration (148 ± 63 vs. 208 ± 70 min; P drainage n = 0 vs. n = 6] occurred more frequently using iRF. Two patients in each group developed a TIA (1.3% vs. 0.6%). Of note, four of five thromboembolic events in the PVAC group (two TIAs and three transient ST elevations during ablation) occurred when all 10 electrodes were used for ablation. Pulmonary vein isolation using PVAC as a 'one-shot-system' has a comparable complication rate but a different risk profile. Pericardial effusion and tamponade occurred more frequently using iRF, whereas thromboembolic events were more prevalent using PVAC. Occurrence of clinically relevant thromboembolic events might be reduced by avoidance of electrode 1 and 10 interaction and uninterrupted anticoagulation, whereas contact force sensing for iRF might minimize pericardial effusion. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

Short and medium term outcomes after rollerball endometrial ablation for menorrhagia.

Science.gov (United States)

Fraser, I S; Angsuwathana, S; Mahmoud, F; Yezerski, S

1993-04-05

To review prospectively the intraoperative, short and medium term outcomes of patients treated by rollerball endometrial ablation during the learning curve for this relatively new procedure. Seventy-seven women with menorrhagia (71 with dysfunctional bleeding; six with additional small intramural myomas) underwent hysteroscopic rollerball endometrial ablation by coagulation diathermy during 1.5% glycine irrigation, after a two-month period of hormonal suppression. OPERATIVE AND SHORT-TERM EFFECTS: These were recorded at operation and six-week follow-up. No serious short-term complications were recorded. Objective measurement of intraoperative blood loss was always less than 20 mL. One woman experienced uterine perforation with a narrow cervical dilator which did not interfere with the ablation, and two patients had mild postoperative uterine infections. One patient experienced persistent postoperative pain. MEDIUM-TERM OUTCOME: This was recorded at each visit, or by telephone, and confirmed by questionnaire at one year. Twenty-five per cent achieved complete amenorrhoea, 29% staining only, 30% light periods, 10% "normal" or erratic periods and 6% were unchanged. Five patients underwent a second ablation, and three of these later underwent hysterectomy. Measured menstrual blood loss fell from 104 +/- 19 mL (mean +/- standard error of mean) to 1.7 +/- 1.1 mL at six months in 18 women. Other menstrual symptoms were also often dramatically reduced. Of those women with dysmenorrhoea, 33% were cured and 43% markedly improved; of those with midcycle pain, 28% were cured and 53% markedly improved; of those with significant premenstrual symptoms, 13% were cured, 47% markedly improved, 11% unchanged, and 6% were worse. This new procedure is a safe and effective treatment for menorrhagia caused by dysfunctional uterine bleeding, with impressive ancillary benefits for dysmenorrhoea, midcycle pain and premenstrual tension. It is often called minimally invasive surgery, but it

US-Guided Femoral and Sciatic Nerve Blocks for Analgesia During Endovenous Laser Ablation

International Nuclear Information System (INIS)

Yilmaz, Saim; Ceken, Kagan; Alimoglu, Emel; Sindel, Timur

2013-01-01

Endovenous laser ablation may be associated with significant pain when performed under standard local tumescent anesthesia. The purpose of this study was to investigate the efficacy of femoral and sciatic nerve blocks for analgesia during endovenous ablation in patients with lower extremity venous insufficiency. During a 28-month period, ultrasound-guided femoral or sciatic nerve blocks were performed to provide analgesia during endovenous laser ablation in 506 legs and 307 patients. The femoral block (n = 402) was performed at the level of the inguinal ligament, and the sciatic block at the posterior midthigh (n = 124), by injecting a diluted lidocaine solution under ultrasound guidance. After the blocks, endovenous laser ablations and other treatments (phlebectomy or foam sclerotherapy) were performed in the standard fashion. After the procedures, a visual analogue pain scale (1–10) was used for pain assessment. After the blocks, pain scores were 0 or 1 (no pain) in 240 legs, 2 or 3 (uncomfortable) in 225 legs, and 4 or 5 (annoying) in 41 legs. Patients never experienced any pain higher than score 5. The statistical analysis revealed no significant difference between the pain scores of the right leg versus the left leg (p = 0.321) and between the pain scores after the femoral versus sciatic block (p = 0.7). Ultrasound-guided femoral and sciatic nerve blocks may provide considerable reduction of pain during endovenous laser and other treatments, such as ambulatory phlebectomy and foam sclerotherapy. They may make these procedures more comfortable for the patient and easier for the operator.

Timing of post 131I ablation diagnostic whole body scan in differentiated thyroid cancer patients. Less than four months post ablation may be too early.

Science.gov (United States)

Winter, M; Winter, J; Heinzel, A; Behrendt, F F; Krohn, T; Mottaghy, F M; Verburg, F A

2015-01-01

to determine whether the first three months after 131I ablation is too early to perform radioiodine diagnostic whole body scintigraphy (dxWBS) in differentiated thyroid carcinoma patients. The files of 462 patients who were treated for DTC in our hospital were reviewed. All patients underwent surgical thyroidectomy. 146 patients had data available on a. a dxWBS which was performed less than four months (max 120 days) after 131I ablation with concurrent stimulated TSH stimulated thyroglobulin (Tg) measurement without further therapeutic measures between ablation and dxWBS and b. a second dxWBS or 131I therapy (rxWBS) within 1.5 years after ablation. A discordance between the initial and follow-up scan was found in 25/129 (19%) patients: of 54 patients with a positive initial dxWBS, scan results of a second dxWBS or rxWBS obtained with a suitable distance to the initial scan contradicted the initial one in 15 patients (27%). New lesions were discovered in 10/74 negative first dxWBS cases (14%). A discordance between the initial and follow-up stimulated Tg was found in 5/129 (4%) patients: 2/90 (2%) of patients with a negative stimulated Tg at initial dxWBS subsequently showed a positive results whereas 3/29 (10%) patients with an initially positive Tg showed a negative Tg level at the second procedure. Less than four months after 131I ablation is too early to perform radioiodine diagnostic whole body scintigraphy with concurrent TSH stimulated Tg measurement. The identification of the right, later, timepoint however requires further research.

Effect of single and fractionated x-irradiation on maze learning ability of mice

International Nuclear Information System (INIS)

Aoyama, Takashi; Norimura, Toshiyuki; Nakamura, Takeshi; Yoshikawa, Isao

1976-01-01

Fifty-six-day-old male ddk mice at the starting of the investigation were used as subjects through the experiment for 64 weeks. After 15 days' preliminary training, and 16 times of weekly trial training using complete maze, 15 mice received a single 224 rads of x-rays (S group), another 15 mice received two 112 rads spaced two weeks apart (F group) and another 15 mice were sham-irradiated (Control group). Then those mice were tested on the multiple T-maze with nine-choice points and change of performance was observed in terms of errorchoices by giving one test trial a week. We introduced the concept of ''confusional trials'' as an index for surmising to what extent mice failed to exhibit good maze learning habits. In the results, the F group showed significantly worse performance than the two other groups at early stages, opposite to it the S group exhibited the same, but at late stages after irradiation. The worse performance of F group should be considered to be due to the psychological after-effect to fractionated irradiation and that for S group could be assumed to be due to the acceleration of aging by the irradiation. (auth.)

Percutaneous Radiofrequency Ablation with Multiple Electrodes for Medium-Sized Hepatocellular Carcinomas

Science.gov (United States)

Lee, Jung; Yoon, Jung-Hwan; Lee, Jae Young; Kim, Se Hyung; Lee, Jeong Eun; Han, Joon Koo; Choi, Byung Ihn

2012-01-01

Objective To prospectively evaluate the safety and short-term therapeutic efficacy of switching monopolar radiofrequency ablation (RFA) with multiple electrodes to treat medium-sized (3.1-5.0 cm), hepatocellular carcinomas (HCC). Materials and Methods In this prospective study, 30 patients with single medium-sized HCCs (mean, 3.5 cm; range, 3.1-4.4 cm) were enrolled. The patients were treated under ultrasonographic guidance by percutaneous switching monopolar RFA with a multichannel RF generator and two or three internally cooled electrodes. Contrast-enhanced CT scans were obtained immediately after RFA, and the diameters and volume of the ablation zones were then measured. Follow-up CT scans were performed at the first month after ablation and every three months thereafter. Technical effectiveness, local progression and remote recurrence of HCCs were determined. Results There were no major immediate or periprocedural complications. However, there was one bile duct stricture during the follow-up period. Technical effectiveness was achieved in 29 of 30 patients (97%). The total ablation time of the procedures was 25.4 ± 8.9 minutes. The mean ablation volume was 73.8 ± 56.4 cm3 and the minimum diameter was 4.1 ± 7.3 cm. During the follow-up period (mean, 12.5 months), local tumor progression occurred in three of 29 patients (10%) with technical effectiveness, while new HCCs were detected in six of 29 patients (21%). Conclusion Switching monopolar RFA with multiple electrodes in order to achieve a sufficient ablation volume is safe and efficient. This method also showed relatively successful therapeutic effectiveness on short-term follow up for the treatment of medium-sized HCCs. PMID:22247634

Model testing of a 10-kg high explosive blast attenuation maze

International Nuclear Information System (INIS)

Bacigalupi, C.M.; Burton, W.A.

1981-01-01

The basement area of the proposed High Explosive Applications Facility (HEAF) at the Lawrence Livermore National Laboratory includes 10-kg HE assembly and process cells, and a 10-kg corridor for the transport of up to 10 kg of HE from the receiving dock to the cells and to the experimental firing tanks. Previous model experiments developed a process cell-maze configuration that attenuated the effects of an accidental 10-kg detonation to acceptable levels (maximum of 10 to 11 psi reflected). This document reports 1/8-scale model tests conducted to confirm the maze design and to determine the blast pressures in adjacent areas in the final HEAF building configuration. In addition, pressure/time information was obtained at selected points in the model expansion chamber to provide the architect-engineer with information for structural design

Isolated core vs. superficial cooling effects on virtual maze navigation.

Science.gov (United States)

Payne, Jennifer; Cheung, Stephen S

2007-07-01

Cold impairs cognitive performance and is a common occurrence in many survival situations. Altered behavior patterns due to impaired navigation abilities in cold environments are potential problems in lost-person situations. We investigated the separate effects of low core temperature and superficial cooling on a spatially demanding virtual navigation task. There were 12 healthy men who were passively cooled via 15 degrees C water immersion to a core temperature of 36.0 degrees C, then transferred to a warm (40 degrees C) water bath to eliminate superficial shivering while completing a series of 20 virtual computer mazes. In a control condition, subjects rested in a thermoneutral (approximately 35 degrees C) bath for a time-matched period before being transferred to a warm bath for testing. Superficial cooling and distraction were achieved by whole-body immersion in 35 degree water for a time-matched period, followed by lower leg immersion in 10 degree C water for the duration of the navigational tests. Mean completion time and mean error scores for the mazes were not significantly different (p > 0.05) across the core cooling (16.59 +/- 11.54 s, 0.91 +/- 1.86 errors), control (15.40 +/- 8.85 s, 0.82 +/- 1.76 errors), and superficial cooling (15.19 +/- 7.80 s, 0.77 +/- 1.40 errors) conditions. Separately reducing core temperature or increasing cold sensation in the lower extremities did not influence performance on virtual computer mazes, suggesting that navigation is more resistive to cooling than other, simpler cognitive tasks. Further research is warranted to explore navigational ability at progressively lower core and skin temperatures, and in different populations.

Epiphysiodesis Made with Radio Frequency Ablation: First Results from a Pilot Study

DEFF Research Database (Denmark)

Shiguetomi Medina, Juan Manuel; Rahbek, Ole; Stødkilde-Jørgensen, Hans

Objective Development of a new technique for epiphysiodesis using radiofrequency ablation on an animal model (pig) that involves less scarring, less exposure to X-rays, and reduces the risk of injuring the surrounding structures compared to current methods. Material and Methods 4 non-mature 40 kg...... performed right after the procedure and 12 weeks later.The length of both tibiae was measured immediately after the ablation and at the end of the study. Results Both legs were equal at the beginning of the study and there was a leg length difference in average of 3.7mm (SD=0.48) at the end. No damage...

Optical fiber biocompatible sensors for monitoring selective treatment of tumors via thermal ablation

Science.gov (United States)

Tosi, Daniele; Poeggel, Sven; Dinesh, Duraibabu B.; Macchi, Edoardo G.; Gallati, Mario; Braschi, Giovanni; Leen, Gabriel; Lewis, Elfed

2015-09-01

Thermal ablation (TA) is an interventional procedure for selective treatment of tumors, that results in low-invasive outpatient care. The lack of real-time control of TA is one of its main weaknesses. Miniature and biocompatible optical fiber sensors are applied to achieve a dense, multi-parameter monitoring, that can substantially improve the control of TA. Ex vivo measurements are reported performed on porcine liver tissue, to reproduce radiofrequency ablation of hepatocellular carcinoma. Our measurement campaign has a two-fold focus: (1) dual pressure-temperature measurement with a single probe; (2) distributed thermal measurement to estimate point-by-point cells mortality.

Microwave Ablation of Pulmonary Malignancies Using a Novel High-energy Antenna System

Energy Technology Data Exchange (ETDEWEB)

Little, Mark W.; Chung, Daniel; Boardman, Philip; Gleeson, Fergus V.; Anderson, Ewan M., E-mail: ewan.anderson@ouh.nhs.uk [Churchill Hospital, Department of Radiology (United Kingdom)

2013-04-15

To evaluate the technical success, safety, and imaging follow-up of malignant pulmonary nodules treated with a novel high-energy percutaneous microwave ablation (MWA) system. Between July 2010 and September 2011, a total of 23 patients, 12 men, mean age 68 (range 30-87) years with 29 pulmonary malignancies of median diameter 19 (range 8-57) mm, underwent computed tomography (CT)-guided MWA with a 16G microwave needle antenna enabling power up to 180 W. Technical success was defined as needle placement in the intended lesion without death or serious injury. Adequacy of ablation was assessed at 24 h on contrast-enhanced CT. Circumferential solid or ground glass opacification >5 mm was used to define an ideal ablation. Local tumor recurrence was assessed at 1, 3, and 6 months after ablation on contrast-enhanced CT. MWA was technically successful in 93 % (n = 27). Mean ablation duration was 3.6 (range 1-9) min. Ten patients (43 %) developed a pneumothorax as a result of the MWA; only 3 (13 %) required placement of a chest drain. Thirty-day mortality rate was 0 %. The mean hospital stay was 1.5 (range 1-7) days. A total of 22 lesions (75 %) were surrounded by {>=}5 mm ground glass or solid opacification after the procedure. At a median follow-up of 6 months, local recurrence was identified in 3 out of 26 lesions, giving a local control rate of 88 %. MWA using a high-power antenna of pulmonary malignancies is safe, technically achievable, and enables fast ablation times.

Laboratory Simulations of Micrometeoroid Ablation

Science.gov (United States)

Thomas, Evan Williamson

Each day, several tons of meteoric material enters Earth's atmosphere, the majority of which consist of small dust particles (micrometeoroids) that completely ablate at high altitudes. The dust input has been suggested to play a role in a variety of phenomena including: layers of metal atoms and ions, nucleation of noctilucent clouds, effects on stratospheric aerosols and ozone chemistry, and the fertilization of the ocean with bio-available iron. Furthermore, a correct understanding of the dust input to the Earth provides constraints on inner solar system dust models. Various methods are used to measure the dust input to the Earth including satellite detectors, radar, lidar, rocket-borne detectors, ice core and deep-sea sediment analysis. However, the best way to interpret each of these measurements is uncertain, which leads to large uncertainties in the total dust input. To better understand the ablation process, and thereby reduce uncertainties in micrometeoroid ablation measurements, a facility has been developed to simulate the ablation of micrometeoroids in laboratory conditions. An electrostatic dust accelerator is used to accelerate iron particles to relevant meteoric velocities (10-70 km/s). The particles are then introduced into a chamber pressurized with a target gas, and they partially or completely ablate over a short distance. An array of diagnostics then measure, with timing and spatial resolution, the charge and light that is generated in the ablation process. In this thesis, we present results from the newly developed ablation facility. The ionization coefficient, an important parameter for interpreting meteor radar measurements, is measured for various target gases. Furthermore, experimental ablation measurements are compared to predictions from commonly used ablation models. In light of these measurements, implications to the broader context of meteor ablation are discussed.

Radiofrequency catheter ablation: A study concerning electrode configuration, lesion size and potential complications

International Nuclear Information System (INIS)

Anfinsen, Ole-Gunnar

1999-01-01

the delivery of RF current in the right atrial free wall. Lung lesions were particularly deep in unipolar 10 mm ablation, because lesion length and depth increased proportionately. Sudden impedance rise most frequently was observed with the bipolar two-catheter technique and was never observed in the dielectrode mode when the power limit was 50 W. 3) When choosing a set temperature for temperature controlled ablations it is important to consider both the location of the thermo sensor in the ablation electrode, the most probable catheter up-tissue orientation at the target of ablation and the estimated local flow (=convective heat loss). 4) In patients subjected to RF ablation, the procedure duration prior to heparin administration and not the delivery of RF current per se, determines activation of haemostasis and fibrinolysis. Some future perspectives are mentioned

Radiofrequency catheter ablation: A study concerning electrode configuration, lesion size and potential complications

Energy Technology Data Exchange (ETDEWEB)

Anfinsen, Ole-Gunnar

1999-07-01

related to the delivery of RF current in the right atrial free wall. Lung lesions were particularly deep in unipolar 10 mm ablation, because lesion length and depth increased proportionately. Sudden impedance rise most frequently was observed with the bipolar two-catheter technique and was never observed in the dielectrode mode when the power limit was 50 W. 3) When choosing a set temperature for temperature controlled ablations it is important to consider both the location of the thermo sensor in the ablation electrode, the most probable catheter up-tissue orientation at the target of ablation and the estimated local flow (=convective heat loss). 4) In patients subjected to RF ablation, the procedure duration prior to heparin administration and not the delivery of RF current per se, determines activation of haemostasis and fibrinolysis. Some future perspectives are mentioned.

Patients’ survival in lung malignancies treated by microwave ablation: our experience on 56 patients

Energy Technology Data Exchange (ETDEWEB)

Belfiore, G.; Ronza, F. [Department of Diagnostic Imaging, “S. Anna-S. Sebastiano” Hospital, Via F. Palasciano, 81100 Caserta (Italy); Belfiore, M.P., E-mail: mariapaola.belfiore@virgilio.it [Institute of Radiology, Second University of Naples, Piazza Miraglia, 80138 Naples (Italy); Serao, N.; Di Ronza, G. [Department of Diagnostic Imaging, “S. Anna-S. Sebastiano” Hospital, Via F. Palasciano, 81100 Caserta (Italy); Grassi, R.; Rotondo, A. [Institute of Radiology, Second University of Naples, Piazza Miraglia, 80138 Naples (Italy)

2013-01-15

Objectives: We retrospectively evaluated percutaneous CT-guided microwave (MW) ablation safety and efficacy in unresectable lung malignancies focusing on patients’ survival. Materials and methods: All procedures were approved by the hospital ethical committee. From 2008 to 2012 we treated 69 unresectable lesions (44 lung cancer, 25 lung metastases) in 56 patients (35 men/21 women; mean age: 61.5 years). Treatment was performed under CT guidance using 14 G needles with a 3 cm active tip and a 55 W MW generator (Vivawave Microwave Coagulation System; Valley Lab). Treatment was performed at 45 W for 6–10 min. Patients were scheduled for a 3 and 6 month CT follow-up to evaluate lesion diameter and enhancement. Survival rate was evaluated by Kaplan–Meier analysis. Results: Ablation procedures were completed according to protocol in all patients. Pneumothorax occurred in 18 patients and 8 required chest tube. Four lesions (all >4.3 cm) were retreated 20 days after the ablation because of peripheral focal areas of residual tumor. Follow-up CT evaluation showed a decrease in maximum diameter in 44/69 lesions (64%) and in 42/59 lesions (71%) at 3 and 6 months, respectively. In all cases no pathologic enhancement was observed. Cancer-specific mortality yielded a survival rate of 69% at 12 months, 54% at 24 months and 49% at 36 months, respectively. An estimate mean for survival time was 27.8 months with a standard error of 2.8 months (95% confidence interval: 22.4–33.2 months). Conclusion: Based on our experience, MW ablation seems to represent a potential safe and effective percutaneous technique in the treatment of lung malignancies. MW ablation may improve survival in patients not suitable to surgery.

Laser, radiofrequency, and ethanol ablation for the management of thyroid nodules.

Science.gov (United States)

Papini, Enrico; Gugliemi, Rinaldo; Pacella, Claudio Maurizio

2016-10-01

The majority of benign thyroid nodules are nearly asymptomatic, remain stable in size, and do not require treatment. However, a minority of patients with growing nodules may complain of local symptoms or have cosmetic concerns, and thus seek surgical consultation. The timely use of ultrasound-guided minimally invasive procedures can change the natural history of benign enlarging thyroid nodules. The procedures produce persistent shrinkage of thyroid nodules and are associated with improvement of local symptoms. Among the various procedures, percutaneous ethanol injection represents the first-line treatment for relapsing thyroid cysts. In solid nonfunctioning nodules, laser and radiofrequency ablation produces a more than 50% reduction in nodular volume that remains persistent over several years. For hyperfunctioning nodules, thermal ablation techniques are not appropriate unless radioactive iodine is contraindicated or not accessible. MITs are best suited for the management of medium or large-sized nodules that are sonographically well visualized. Conversely, large nodules or nodular goiters that extend into the chest are difficult to treat. MITs are performed in outpatient clinics, are less expensive, and have a lower risk of complications, compared to surgery, and usually do not induce thyroid dysfunction. However, malignancy should be ruled out with a dedicated ultrasound neck assessment and repeat fine needle aspiration of the lesion before treatment.

Ventricular fibrillation occurring after atrioventricular node ablation despite minimal difference between pre- and post-ablation heart rates.

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Squara, F; Theodore, G; Scarlatti, D; Ferrari, E

2017-02-01

We report the case of an 82-year-old man presenting with ventricular fibrillation (VF) occurring acutely after atrioventricular node (AVN) ablation. This patient had severe valvular cardiomyopathy, chronic atrial fibrillation (AF), and underwent prior to the AVN ablation a biventricular implantable cardiac defibrillator positioning. The VF was successfully cardioverted with one external electrical shock. What makes this presentation original is that the pre-ablation spontaneous heart rate in AF was slow (84 bpm), and that VF occurred after ablation despite a minimal heart rate drop of only 14 bpm. VF is the most feared complication of AVN ablation, but it had previously only been described in case of acute heart rate drop after ablation of at least 30 bpm (and more frequently>50 bpm). This case report highlights the fact that VF may occur after AVN ablation regardless of the heart rate drop, rendering temporary fast ventricular pacing mandatory whatever the pre-ablation heart rate. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Optimizing radiofrequency ablation of paroxysmal and persistent atrial fibrillation by direct catheter force measurement-a case-matched comparison in 198 patients.

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Sigmund, Elisabeth; Puererfellner, Helmut; Derndorfer, Michael; Kollias, Georgios; Winter, Siegmund; Aichinger, Josef; Nesser, Hans-Joachim; Martinek, Martin

2015-02-01

Sufficient electrode-tissue contact is crucial for adequate lesion formation in radiofrequency catheter ablation (RFCA). We assessed the impact of direct catheter force measurement on acute procedural parameters and outcome of RFCA for paroxysmal and persistent atrial fibrillation (AF). Ninety-nine consecutive patients (70% men) with paroxysmal (63.6%) or persistent AF underwent left atrial RFCA using a 3.5-mm open-irrigated-tip (OIT) catheter with contact force measurement capabilities (group 1). For comparison a case-matched cohort with standard OIT catheters was used (99 patients; group 2). Case matching included gender, type of AF, number or RFCA procedures, and type of procedure. Procedural data showed a significant decline in radiofrequency ablation time from 52 ± 20 to 44 ± 16 minutes (P = 0.003) with a remarkable mean reduction in overall procedure time of 34 minutes (P = 0.0001; 225.8 ± 53.1 vs 191.9 ± 53.3 minutes). In parallel, the total fluoroscopy time could be significantly reduced from 28.5 ± 11.0 to 19.9 ± 9.3 minutes (P = 0.0001) as well as fluoroscopy dose from 74.1 ± 58.0 to 56.7 ± 38.9 Gy/cm(2) (P = 0.016). Periprocedural complications were similar in both groups. The use of contact force sensing technology is able to significantly reduce ablation, procedure, and fluoroscopy times as well as dose in RFCA of AF in a mixed case-matched group of paroxysmal and persistent AF. Energy delivery is substantially reduced by avoiding radiofrequency ablation in positions with insufficient surface contact. Additionally 12-month outcome data showed increased efficacy. Such time saving and equally safe technology may have a relevant impact on laboratory management and increased cost effectiveness. © 2014 Wiley Periodicals, Inc.

Direct quantitative comparison of molecular responses in photodamaged human skin to fractionated and fully ablative carbon dioxide laser resurfacing.

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Orringer, Jeffrey S; Sachs, Dana L; Shao, Yuan; Hammerberg, Craig; Cui, Yilei; Voorhees, John J; Fisher, Gary J

2012-10-01

Fractionated ablative laser resurfacing has become a widely used treatment modality. Its clinical results are often found to approach those of traditional fully ablative laser resurfacing. To directly compare the molecular changes that result from fractionated and fully ablative carbon dioxide (CO(2)) laser resurfacing in photodamaged human skin. Photodamaged skin of 34 adult volunteers was focally treated at distinct sites with a fully ablative CO(2) laser and a fractionated CO(2) laser. Serial skin samples were obtained at baseline and several time points after treatment. Real-time reverse transcriptase polymerase chain reaction technology and immunohistochemistry were used to quantify molecular responses to each type of laser treatment. Fully ablative and fractionated CO(2) laser resurfacing induced significant dermal remodeling and collagen induction. After a single treatment, fractionated ablative laser resurfacing resulted in collagen induction that was approximately 40% to 50% as pronounced as that induced by fully ablative laser resurfacing. The fundamental cutaneous responses that result from fully ablative and fractionated carbon dioxide laser resurfacing are similar but differ in magnitude and duration, with the fully ablative procedure inducing relatively greater changes including more pronounced collagen induction. However, the molecular data reported here provide substantial support for fractionated ablative resurfacing as an effective treatment modality for improving skin texture. © 2012 by the American Society for Dermatologic Surgery, Inc. Published by Wiley Periodicals, Inc.

Near-real-time feedback control system for liver thermal ablations based on self-referenced temperature imaging

International Nuclear Information System (INIS)

Keserci, Bilgin M.; Kokuryo, Daisuke; Suzuki, Kyohei; Kumamoto, Etsuko; Okada, Atsuya; Khankan, Azzam A.; Kuroda, Kagayaki

2006-01-01

Our challenge was to design and implement a dedicated temperature imaging feedback control system to guide and assist in a thermal liver ablation procedure in a double-donut 0.5T open MR scanner. This system has near-real-time feedback capability based on a newly developed 'self-referenced' temperature imaging method using 'moving-slab' and complex-field-fitting techniques. Two phantom validation studies and one ex vivo experiment were performed to compare the newly developed self-referenced method with the conventional subtraction method and evaluate the ability of the feedback control system in the same MR scanner. The near-real-time feedback system was achieved by integrating the following primary functions: (1) imaging of the moving organ temperature; (2) on-line needle tip tracking; (3) automatic turn-on/off the heating devices; (4) a Windows operating system-based novel user-interfaces. In the first part of the validation studies, microwave heating was applied in an agar phantom using a fast spoiled gradient recalled echo in a steady state sequence. In the second part of the validation and ex vivo study, target visualization, treatment planning and monitoring, and temperature and thermal dose visualization with the graphical user interface of the thermal ablation software were demonstrated. Furthermore, MR imaging with the 'self-referenced' temperature imaging method has the ability to localize the hot spot in the heated region and measure temperature elevation during the experiment. In conclusion, we have demonstrated an interactively controllable feedback control system that offers a new method for the guidance of liver thermal ablation procedures, as well as improving the ability to assist ablation procedures in an open MR scanner

Economic and clinical benefits of endometrial radiofrequency ablation compared with other ablation techniques in women with menorrhagia: a retrospective analysis with German health claims data

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Bischoff-Everding C

2016-01-01

Full Text Available Christoph Bischoff-Everding,1 Ruediger Soeder,2 Benno Neukirch3 1HGC GesundheitsConsult GmbH, Duesseldorf, Germany; 2Gynecological Joint Practice, Mainz, Germany; 3Faculty of Health Care, Hochschule Niederrhein – University of Applied Sciences, Krefeld, Germany Objective: To evaluate the economic and clinical benefits of endometrial radiofrequency ablation (RFA compared with other ablation techniques for the treatment of menorrhagia.Methods: Using German health claims data, women meeting defined inclusion criteria for the intervention group (RFA were selected. A comparable control group (other endometrial ablations was established using propensity score matching. These two groups were compared during the quarter of treatment (QoT and a follow-up of 2 years for the following outcomes: costs during QoT and during follow-up, repeated menorrhagia diagnoses during follow-up and necessary retreatments during follow-up. Results: After performing propensity score matching, 50 cases could be allocated to the intervention group, while 38 were identified as control cases. Patients in the RFA group had 5% fewer repeat menorrhagia diagnoses (40% vs 45%; not significant and 5% fewer treatments associated with recurrent menorrhagia (6% vs 11%; not significant than cases in the control group. During the QoT, the RFA group incurred €578 additional costs (€2,068 vs €1,490; ns. However, during follow-up, the control group incurred €1,254 additional costs (€4,561 vs €5,815; ns, with medication, outpatient physician consultations, and hospitals costs being the main cost drivers. However, none of the results were statistically significant. Conclusion: Although RFA was more cost-intensive in the QoT compared with other endometrial ablation techniques, an average total savings of €676 was generated during the follow-up period. While having evidence that RFA is clinically equivalent to other endometrial ablation procedures, we generated indications that

Long-term Results after CT-Guided Percutaneous Ethanol Ablation for the Treatment of Hyperfunctioning Adrenal Disorders

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Nathan Elie Frenk

Full Text Available OBJECTIVES: To evaluate the safety and long-term efficacy of computed tomography-guided percutaneous ethanol ablation for benign primary and secondary hyperfunctioning adrenal disorders. METHOD: We retrospectively evaluated the long-term results of nine patients treated with computed tomography-guided percutaneous ethanol ablation: eight subjects who presented with primary adrenal disorders, such as pheochromocytoma, primary macronodular adrenal hyperplasia and aldosterone-producing adenoma, and one subject with Cushing disease refractory to conventional treatment. Eleven sessions were performed for the nine patients. The patient data were reviewed for the clinical outcome and procedure-related complications over ten years. RESULTS: Patients with aldosterone-producing adenoma had clinical improvement: symptoms recurred in one case 96 months after ethanol ablation, and the other patient was still in remission 110 months later. All patients with pheochromocytoma had clinical improvement but were eventually submitted to surgery for complete remission. No significant clinical improvement was seen in patients with hypercortisolism due to primary macronodular adrenal hyperplasia or Cushing disease. Major complications were seen in five of the eleven procedures and included cardiovascular instability and myocardial infarction. Minor complications attributed to sedation were seen in two patients. CONCLUSION: Computed tomography-guided ethanol ablation does not appear to be suitable for the long-term treatment of hyperfunctioning adrenal disorders and is not without risks.

Use of maze in cyclotron hoppers

International Nuclear Information System (INIS)

Fernandes, Fernando A.; Alves, Juliano S.; Fochesatto, Cintia; Cerioli, Luciane; Borges, Joao Alfredo; Gonzalez, Delfin; Silva, Daniel C.

2013-01-01

Introduction: the increasing number of cyclotrons in Brazil due to constitutional amendment 49 /06 that enabled the production of radiopharmaceuticals with a short half - life by private companies. The radionuclides used for PET - CT require production centers near or within the diagnostic centers. In order to minimize maintenance and operating risks, gaining efficiency, our facility was the first in Brazil to use the access to a cyclotron bunker via maze, rather than armored door stopper type. Materials: the design calculations were based on the Monte Carlo method (MCNP5 - Monte Carlo N-Particletransportcode version 5). At the ends of the labyrinth are installed a door of polyethylene, for thermalization of neutrons, and other of wood for limiting access. Both legs of the maze have wall thickness of 100cm. In inspection Brazilian CNEN realize measures of dose rate for neutrons and gamma 9 points: 7 around the bunker, 1 over the bunker and 1 in the exhaust with the cyclotron operating with maximum load, double beam of 50uA for 2 hours. After commissioning were carried out around the bunker, the following measures: cumulative dose in three months with dosimeters for neutron rate dose with a gas proportional detector type filled with 3 He and polyethylene neutron moderator and dose rate with a Geiger - Mueller detector for gamma radiation. Readings with neutron detectors were classified as background radiation and dose rates were always below the limits established in standard EN 3.01, and the calculation of the predicted regardless of the intensity of irradiation inside the bunker. Conclusion: the use of labyrinths as a way to access the bunkers cyclotron has been shown to be effective as the radiation shielding and efficient by allowing quick and easy access, virtually eliminating the maintenance

Declarative virtual water maze learning and emotional fear conditioning in primary insomnia.

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Kuhn, Marion; Hertenstein, Elisabeth; Feige, Bernd; Landmann, Nina; Spiegelhalder, Kai; Baglioni, Chiara; Hemmerling, Johanna; Durand, Diana; Frase, Lukas; Klöppel, Stefan; Riemann, Dieter; Nissen, Christoph

2018-05-02

Healthy sleep restores the brain's ability to adapt to novel input through memory formation based on activity-dependent refinements of the strength of neural transmission across synapses (synaptic plasticity). In line with this framework, patients with primary insomnia often report subjective memory impairment. However, investigations of memory performance did not produce conclusive results. The aim of this study was to further investigate memory performance in patients with primary insomnia in comparison to healthy controls, using two well-characterized learning tasks, a declarative virtual water maze task and emotional fear conditioning. Twenty patients with primary insomnia according to DSM-IV criteria (17 females, three males, 43.5 ± 13.0 years) and 20 good sleeper controls (17 females, three males, 41.7 ± 12.8 years) were investigated in a parallel-group study. All participants completed a hippocampus-dependent virtual Morris water maze task and amygdala-dependent classical fear conditioning. Patients with insomnia showed significantly delayed memory acquisition in the virtual water maze task, but no significant difference in fear acquisition compared with controls. These findings are consistent with the notion that memory processes that emerge from synaptic refinements in a hippocampal-neocortical network are particularly sensitive to chronic disruptions of sleep, while those in a basic emotional amygdala-dependent network may be more resilient. © 2018 European Sleep Research Society.

Osteoid osteomas in common and in technically challenging locations treated with computed tomography-guided percutaneous radiofrequency ablation

International Nuclear Information System (INIS)

Mylona, Sophia; Patsoura, Sofia; Karapostolakis, Georgios; Galani, Panagiota; Pomoni, Anastasia; Thanos, Loukas

2010-01-01

To evaluate the efficacy of computed tomography (CT)-guided radiofrequency (RF) ablation for the treatment of osteoid osteomas in common and in technically challenging locations. Twenty-three patients with osteoid osteomas in common (nine cases) and technically challenging [14 cases: intra-articular (n = 7), spinal (n = 5), metaphyseal (n = 2)] positions were treated with CT-guided RF ablation. Therapy was performed under conscious sedation with a seven-array expandable RF electrode for 8-10 min at 80-110 C and power of 90-110 W. The patients went home under instruction. A brief pain inventory (BPI) score was calculated before and after (1 day, 4 weeks, 6 months and 1 year) treatment. All procedures were technically successful. Primary clinical success was 91.3% (21 of total 23 patients), despite the lesions' locations. BPI score was dramatically reduced after the procedure, and the decrease in BPI score was significant (P < 0.001, paired t-test; n - 1 = 22) for all periods during follow up. Two patients had persistent pain after 1 month and were treated successfully with a second procedure (secondary success rate 100%). No immediate or delayed complications were observed. CT-guided RF ablation is safe and highly effective for treatment of osteoid osteomas, even in technically difficult positions. (orig.)

Right atrial angiographic evaluation of the posterior isthmus: relevance for ablation of typical atrial flutter.

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Heidbüchel, H; Willems, R; van Rensburg, H; Adams, J; Ector, H; Van de Werf, F

2000-05-09

Gaining anatomic information about the posterior isthmus is not generally part of flutter ablation procedures. We postulated that right atrial (RA) angiography could rationalize the ablation approach by revealing the conformation of the isthmus. In 100 consecutive patients, biplane RA angiography was performed before ablation to guide catheter contact with the isthmus along its length. Angiography showed a wide variation in the width of the isthmus (17 to 54 mm; 31.3+/-7.9), its angle with the inferior vena cava in the right anterior oblique projection (68 degrees to 114 degrees; 90.3+/-9.0 degrees ), and its lateral position relative to the inferior vena cava in the left anterior oblique projection. A deep sub-Eustachian recess was revealed in 47%, with a mean depth of 4.3+/-2.1 mm (1.5 to 9.4). A Eustachian valve was visualized in 24%. Ablation resulted in bidirectional conduction block (which could be transient) in all, with a median of 2 dragging radiofrequency (RF) applications (2.3+/-2.5 RF applications; 57 degrees C, deep pouches. The number of RF applications decreased statistically throughout the study, indicating a learning curve. No patient had a recurrence after a follow-up of 13+/-11 months. Right atrial angiography reveals a highly variable isthmus anatomy, often showing particular configurations that can make ablation more laborious. Rational adaptation of the ablation approach to these anatomic findings may contribute to successful ablation.

Water spray assisted ultrashort laser pulse ablation

International Nuclear Information System (INIS)

Silvennoinen, M.; Kaakkunen, J.J.J.; Paivasaari, K.; Vahimaa, P.

2013-01-01

Highlights: ► We show the novel method to use multibeam processing with ultrashort pulses efficiently. ► Sprayed thin water layer on ablation zone enhances ablation rate and quality. ► In some cases this method also enables ablation of the deeper and straighter holes compared to ones made without the water layer. ► Method also makes possible to directly write features without the self-organizing structures. - Abstract: We have studied femtosecond ablation under sprayed thin water film and its influence and benefits compared with ablation in the air atmosphere. These have been studied in case of the hole and the groove ablation using IR femtosecond laser. Water enhances the ablation rate and in some situations it makes possible to ablate the holes with a higher aspect ratio. While ablating the grooves, the water spray allows using the high fluences without the generation of the self-organized structures.

Radiofrequency ablation combined with transcatheter arterial embolisation in rabbit liver: investigation of the ablation zone according to the time interval between the two therapies.

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Lee, I J; Kim, Y I; Kim, K W; Kim, D H; Ryoo, I; Lee, M W; Chung, J W

2012-11-01

This study was designed to evaluate the extent of the radiofrequency ablation zone in relation to the time interval between transcatheter arterial embolisation (TAE) and radiofrequency ablation (RFA) and, ultimately, to determine the optimal strategy of combining these two therapies for hepatocellular carcinoma. 15 rabbits were evenly divided into three groups: Group A was treated with RFA alone; Group B was treated with TAE immediately followed by RFA; and Group C was treated with TAE followed by RFA 5 days later. All animals underwent perfusion CT (PCT) scans immediately after RFA. Serum liver transaminases were measured to evaluate acute liver damage. Animals were euthanised for pathological analysis of ablated tissues 10 days after RFA. Non-parametric analyses were conducted to compare PCT indices, the RFA zone and liver transaminase levels among the three experimental groups. Group B showed a significantly larger ablation zone than the other two groups. Arterial liver perfusion and hepatic perfusion index represented well the perfusion decrease after TAE on PCT. Although Group B showed the most elevated liver transaminase levels at 1 day post RFA, the enzymes decreased to levels that were not different from the other groups at 10 days post-RFA. When combined TAE and RFA therapy is considered, TAE should be followed by RFA as quickly as possible, as it can be performed safely without serious hepatic deterioration, despite the short interval between the two procedures.

The effect of ethanol infusion on the size of the ablated lesion in radiofrequency thermal ablation: A pilot study

International Nuclear Information System (INIS)

Kim, Young Sun; Rhim, Hyun Chul; Koh, Byung Hee; Cho, On Koo; Seo, Heung Suk; Kim, Yong Soo; Joo, Kyoung Bin

2001-01-01

To assess the effect of ethanol infusion on the size of ablated lesion during radiofrequency (RF) thermal ablation. We performed an ex vivo experimental study using a total of 15 pig livers. Three groups were designed: 1)normal control (n=10), 2) saline infusion (n=10) 3) ethanol infusion (n=10). Two radiofrequency ablations were done using a 50 watt RF generator and a 15 guage expandable elections with four prongs in each liver. During ablation for 8 minutes, continuous infusion of fluid at a rate of 0.5 ml/min through the side arm of electrode was performed. We checked the frequency of the 'impeded-out' phenomenon due to abrupt increase of impedance during ablation. Size of ablated lesion was measured according to length, width, height, and subsequently volume after the ablations. The sizes of the ablated lesions were compared between the three groups. 'Impeded-out' phenomenon during ablation was noted 4 times in control group, although that never happened in saline or ethanol infusion groups. There were significant differences in the volumes of ablated lesions between control group (10.62 ± 1.45 cm 3 ) and saline infusion group (15.33 ± 2.47 cm 3 ), and saline infusion group and ethanol infusion group (18.78 ± 3.58 cm 3 ) (p<0.05). Fluid infusion during radiofrequency thermal ablation decrease a chance of charming and increase the volume of the ablated lesion. Ethanol infusion during ablation may induce larger volume of ablated lesion than saline infusion.

Strict sequential catheter ablation strategy targeting the pulmonary veins and superior vena cava for persistent atrial fibrillation.

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Yoshiga, Yasuhiro; Shimizu, Akihiko; Ueyama, Takeshi; Ono, Makoto; Fukuda, Masakazu; Fumimoto, Tomoko; Ishiguchi, Hironori; Omuro, Takuya; Kobayashi, Shigeki; Yano, Masafumi

2018-08-01

An effective catheter ablation strategy, beyond pulmonary vein isolation (PVI), for persistent atrial fibrillation (AF) is necessary. Pulmonary vein (PV)-reconduction also causes recurrent atrial tachyarrhythmias. The effect of the PVI and additional effect of a superior vena cava (SVC) isolation (SVCI) was strictly evaluated. Seventy consecutive patients with persistent AF who underwent a strict sequential ablation strategy targeting the PVs and SVC were included in this study. The initial ablation strategy was a circumferential PVI. A segmental SVCI was only applied as a repeat procedure when patients demonstrated no PV-reconduction. After the initial procedure, persistent AF was suppressed in 39 of 70 (55.7%) patients during a median follow-up of 32 months. After multiple procedures, persistent AF was suppressed in 46 (65.7%) and 52 (74.3%) patients after receiving the PVI alone and PVI plus SVCI strategies, respectively. In 6 of 15 (40.0%) patients with persistent AF resistant to PVI, persistent AF was suppressed. The persistent AF duration independently predicted persistent AF recurrences after multiple PVI alone procedures [HR: 1.012 (95% confidence interval: 1.006-1.018); pstrategies [HR: 1.018 (95% confidence interval: 1.011-1.025); pstrategies, respectively. The outcomes of the PVI plus SVCI strategy were favorable for patients with shorter persistent AF durations. The initial SVCI had the additional effect of maintaining sinus rhythm in some patients with persistent AF resistant to PVI. Copyright © 2018 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

Enhancement After Myopic Small Incision Lenticule Extraction (SMILE) Using Surface Ablation.

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Siedlecki, Jakob; Luft, Nikolaus; Kook, Daniel; Wertheimer, Christian; Mayer, Wolfgang J; Bechmann, Martin; Wiltfang, Rainer; Priglinger, Siegfried G; Sekundo, Walter; Dirisamer, Martin

2017-08-01

To report the feasibility and outcomes of surface ablation after small incision lenticule extraction (SMILE). In this retrospective evaluation of 1,963 SMILE procedures, 43 eyes (2.2%) were re-treated at three separate clinics. Of these, 40 eyes of 28 patients with a follow-up of at least 3 months were included in the analysis. During surface ablation, mitomycin C was applied for haze prevention. Spherical equivalent was -6.35 ± 1.31 diopters (D) before SMILE and -0.86 ± 0.43 D before surface ablation. Surface ablation was performed after a mean of 9.82 ± 5.27 months and resulted in a spherical equivalent of 0.03 ± 0.57 D at 3 months (P line. Corrected distance visual acuity (CDVA) remained unchanged with 0.01 ± 0.07 logMAR before versus -0.01 ± 0.05 logMAR after re-treatment (P = .99). Six eyes (15.0%) lost one line of CDVA, but final CDVA was 0.00 logMAR in four and 0.10 logMAR in two of these cases. The safety and efficacy indices were 1.06 and 0.90 at 3 months, respectively. Three of the four surface ablation profiles (Triple-A, tissue-saving algorithm, and topography-guided) resulted in equally good results, whereas enhancement with the aspherically optimized profile (ASA), used in two eyes, resulted in overcorrection (+1.38 and +1.75 D). Combined with the intraoperative application of mitomycin C, surface ablation seems to be a safe and effective method of secondary enhancement after SMILE. Due to the usually low residual myopia, the ASA profile is not recommended in these cases. [J Refract Surg. 2017;33(8):513-518.]. Copyright 2017, SLACK Incorporated.

The APPLE Score - A Novel Score for the Prediction of Rhythm Outcomes after Repeat Catheter Ablation of Atrial Fibrillation.

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Jelena Kornej

Full Text Available Arrhythmia recurrences after catheter ablation occur in up to 50% within one year but their prediction remains challenging. Recently, we developed a novel score for the prediction of rhythm outcomes after single AF ablation demonstrating superiority to other scores. The current study was performed to 1 prove the predictive value of the APPLE score in patients undergoing repeat AF ablation and 2 compare it with the CHADS2 and CHA2DS2-VASc scores.Rhythm outcome between 3-12 months after AF ablation were documented. The APPLE score (one point for Age >65 years, Persistent AF, imPaired eGFR (<60 ml/min/1.73m2, LA diameter ≥43 mm, EF <50% was calculated in every patient before procedure.379 consecutive patients from The Leipzig Heart Center AF Ablation Registry (60±10 years, 65% male, 70% paroxysmal AF undergoing repeat AF catheter ablation were included. Arrhythmia recurrences were observed in 133 patients (35%. While the CHADS2 (AUC 0.577, p = 0.037 and CHA2DS2-VASc scores (AUC 0.590, p = 0.015 demonstrated low predictive value, the APPLE score showed better prediction of arrhythmia recurrences (AUC 0.617, p = 0.002 than other scores (both p<0.001. Compared to patients with an APPLE score of 0, the risk (OR for arrhythmia recurrences was 2.9, 3.0 and 6.0 (all p<0.01 for APPLE scores 1, 2, or ≥3, respectively.The novel APPLE score is superior to the CHADS2 and CHA2DS2-VASc scores for prediction of rhythm outcomes after repeat AF catheter ablation. It may be helpful to identify patients with low, intermediate or high risk for recurrences after repeat procedure.

Transcatheter radiofrequency ablation under the guidance of three-dimensional mapping for the treatment of complex cardiac arrhythmias

International Nuclear Information System (INIS)

Hong Lang; Wang Hong; Lai Hengli; Ying Qiulin; Chen Zhangqiang; Lu Linxiang; Qiu Yun; Xiao Chengwei

2010-01-01

Objective: To investigate the effectiveness and safety of transcatheter radiofrequency ablation guided by a three-dimensional mapping system (Ensite or Carto) for the treatment of complex cardiac arrhythmias. Methods: A cohort of 123 consecutive hospitalized inpatients during the period from February 2006 to December 2008 were selected for this study. These patients suffered from various arrhythmias, including paroxysmal atrial fibrillation (n = 58), persistent or permanent atrial fibrillation (n = 10), atrial flutter (n = 13), atrial tachycardia (n = 12) and ventricular tachycardia or frequent ventricular premature beats (n = 30). Transcatheter radiofrequency ablation for arrhythmias was performed under the guidance of an EnSite3000 / NavX or Array mapping system in 80 cases, and under the guidance of a CARTO mapping system in the remaining 43 cases. Results: Successful ablation of arrhythmias was obtained by single operation in 106 cases (86.18%), including 59 cases with atrial fibrillation, 11 cases with atrial flutter, 10 cases with atrial tachycardia, and 26 cases with ventricular tachycardia or premature ventricular beat.Ablation procedure was carried out and was successful in 10 cases with a successful rate of 94.31%, including 5 cases with atrial fibrillation, 1 case with recurred atrial flutter, 1 case with recurrent atrial tachycardia, and 3 cases with ventricular tachycardia or premature ventricular beat.After operation, complications occurred in 6 cases, including cardiac tamponade in 4 cases, distal embolism of the left anterior descending coronary artery in 1 case, and pulmonary embolism in 1 case. Conclusion: Three-dimensional mapping system can clearly and stereoscopically display the cardiac structures. Therefore, this technique is of great value in guiding the transcatheter radiofrequency ablation for complex arrhythmias, in improving the success rate of ablation and in increasing the safety of the procedure. (authors)

Clinical Benefit of Ablating Localized Sources for Human Atrial Fibrillation: The Indiana University FIRM Registry.

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Miller, John M; Kalra, Vikas; Das, Mithilesh K; Jain, Rahul; Garlie, Jason B; Brewster, Jordan A; Dandamudi, Gopi

2017-03-14

Mounting evidence shows that localized sources maintain atrial fibrillation (AF). However, it is unclear in unselected "real-world" patients if sources drive persistent atrial fibrillation (PeAF), long-standing persistent atrial fibrillation (LPeAF), or paroxysmal atrial fibrillation (PAF); if right atrial sites are important; and what the long-term success of source ablation is. The aim of this study was to analyze the role of rotors and focal sources in a large academic registry of consecutive patients undergoing source mapping for AF. One hundred seventy consecutive patients (mean age 59 ± 12 years, 79% men) with PAF (37%), PeAF (31%), or LPeAF (32%). Of these, 73 (43%) had undergone at least 1 prior ablation attempt (mean 1.9 ± 0.8; range: 1 to 4). Focal impulse and rotor modulation (FIRM) with an endocardial basket catheter was used in all cases. FIRM analysis revealed sources in the right atrium in 85% of patients (1.8 ± 1.3) and in the left atrium in 90% of patients (2.0 ± 1.3). FIRM ablation terminated AF to sinus rhythm or atrial flutter or tachycardia in 59% (PAF), 37% (PeAF), and 19% (LPeAF) of patients, with 15 of 67 terminations due to right atrial ablation. On follow-up, freedom from AF after a single FIRM procedure for the entire series was 95% (PAF), 83% (PeAF), and 82% (LPeAF) at 1 year and freedom from all atrial arrhythmias was 77% (PAF), 75% (PeAF), and 57% (LPeAF). In the Indiana University FIRM registry, FIRM-guided ablation produced high single-procedure success, mostly in patients with nonparoxysmal AF. Data from mapping, acute terminations, and outcomes strongly support the mechanistic role of biatrial rotors and focal sources in maintaining AF in diverse populations. Randomized trials of FIRM-guided ablation and mechanistic studies to determine how rotors form, progress, and regress are needed. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Novel Approaches for the Treatment of the Patient with Resistant Hypertension: Renal Nerve Ablation

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Gulati, Vinay; White, William B.

2013-01-01

Sympathetic innervation of the kidneys plays a major role in the pathogenesis of hypertension through modulation of renin secretion, glomerular filtration rate and renal absorption of sodium. Targeted interventions for renal nerve ablation are being developed for treatment of drug resistant hypertension in the USA and rest of the world. Early studies with the use of radiofrequency based renal denervation systems have shown encouraging results with significant reduction of blood pressure in patients inadequately controlled despite nearly maximal drug therapy regimens. Thus far, the renal denervation procedure has been associated with minimal side effects. Long term efficacy and safety beyond 3 years needs to be determined for renal nerve ablation. This review focuses on the physiology of the renal sympathetic system, the rationale for renal nerve ablation and current evidence in support of the available therapeutic renal denervation systems. PMID:24244757

"Rescue" ablation of electrical storm in arrhythmogenic right ventricular cardiomyopathy in pregnancy.

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Stec, Sebastian; Krynski, Tomasz; Baran, Jakub; Kulakowski, Piotr

2013-08-13

Radiofrequency ablation (RFCA) became a treatment of choice in patients with recurrent ventricular tachycardia, ventricular fibrillation, and appropriate interventions of implanted cardioverter-defibrillator (ICD), however, electrical storm (ES) ablation in a pregnant woman has not yet been reported. We describe a case of a successful rescue ablation of recurrent ES in a 26-year-old Caucasian woman during her first pregnancy (23rd week). The arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) was diagnosed 3 years earlier and several drugs as well as 2 ablations failed to control recurrences of ventricular tachycardia. RFCA was performed on the day of the third electric storm. The use of electroanatomic mapping allowed very low X-ray exposure, and after applications in the right ventricular outflow tract, arrhythmia disappeared. Three months after ablation, a healthy girl was delivered without any complications. During twelve-month follow-up there was no recurrence of ventricular tachycardia or ICD interventions. This case documents the first successful RFCA during ES due to recurrent unstable ventricular arrhythmias in a patient with ARVD/C in pregnancy. Current guidelines recommend metoprolol, sotalol and intravenous amiodarone for prevention of recurrent ventricular tachycardia in pregnancy, however, RFCA should be considered as a therapeutic option in selected cases. The use of 3D navigating system and near zero X-ray approach is associated with minimal radiation exposure for mother and fetus as well as low risk of procedural complication.

2-Methyl-6-(phenylethynyl pyridine (MPEP reverses maze learning and PSD-95 deficits in Fmr1 knock-out mice.

Directory of Open Access Journals (Sweden)

Réno Michelle Gandhi

2014-03-01

Full Text Available Fragile X syndrome (FXS is caused by the lack of expression of the fragile X mental retardation protein (FMRP, which results in intellectual disability and other debilitating symptoms including impairment of visual-spatial functioning. FXS is the only single-gene disorder that is highly co-morbid with autism spectrum disorder and can therefore provide insight into its pathophysiology. Lack of FMRP results in altered group I metabotropic glutamate receptor (mGluR signalling, which is a target for putative treatments. The Hebb-Williams (H-W mazes are a set of increasingly complex spatial navigation problems that depend on intact hippocampal and thus mGluR-5 functioning. In the present investigation, we examined whether an antagonist of mGluR-5 would reverse previously described behavioural deficits in Fmr1 KO mice. Mice were trained on a subset of the H-W mazes and then treated with either 20 mg/kg of an mGluR-5 antagonist, 2-Methyl-6-(phenylethynyl pyridine (MPEP; n = 11 or an equivalent dose of saline (n = 11 prior to running test mazes. Latency and errors were dependent variables recorded during the test phase. Immediately after completing each test, marble-burying behavior was assessed which confirmed that the drug treatment was pharmacologically active during maze learning. Although latency was not statistically different between the groups, MPEP treated Fmr1 KO mice made significantly fewer errors on mazes deemed more difficult suggesting a reversal of the behavioural deficit. MPEP treated mice were also less perseverative and impulsive when navigating mazes. Furthermore, MPEP treatment reversed PSD-95 protein deficits in Fmr1 KO treated mice, whereas levels of a control protein (β-tubulin remained unchanged. These data further validate MPEP as a potentially beneficial treatment for FXS. Our findings also suggest that adapted H-W mazes may be a useful tool to document alterations in behavioural functioning following pharmacological

Ablation of Solid Hydrogen in a Plasma

DEFF Research Database (Denmark)

Jørgensen, L. W.; Sillesen, Alfred Hegaard

1979-01-01

Several hydrogen pellet ablation models based on the formation of a shielding neutral cloud have been reported by different authors. The predicted ablation rates are shown to follow almost the same scaling law and this is used to explain the authors' ablation experiment.......Several hydrogen pellet ablation models based on the formation of a shielding neutral cloud have been reported by different authors. The predicted ablation rates are shown to follow almost the same scaling law and this is used to explain the authors' ablation experiment....

Validating the Electric Maze Task as a Measure of Planning

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Sheppard, Kelly W.; Cheatham, Carol L.

2017-01-01

The Electric Maze Task (EMT) is a novel planning task designed to allow flexible testing of planning abilities across a broad age range and to incorporate manipulations to test underlying planning abilities, such as working-memory and inhibitory control skills. The EMT was tested in a group of 63 typically developing 7- to 12-year-olds.…

History of hyperthyroidism and long-term outcome of catheter ablation of drug-refractory atrial fibrillation.

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Wongcharoen, Wanwarang; Lin, Yenn-Jiang; Chang, Shih-Lin; Lo, Li-Wei; Hu, Yu-Feng; Chung, Fa-Po; Chong, Eric; Chao, Tze-Fan; Tuan, Ta-Chuan; Chang, Yao-Ting; Lin, Chin-Yu; Liao, Jo-Nan; Lin, Yi-Chun; Chen, Yun-Yu; Chen, Shih-Ann

2015-09-01

Hyperthyroidism is a known reversible cause of atrial fibrillation (AF). However, some patients remain in AF despite restoration of euthyroid status. The purpose of this study was to compare the electrophysiologic characteristics and long-term ablation outcome in AF patients with and without history of hyperthyroidism. The study enrolled 717 consecutive patients with AF who underwent first AF ablation, which involved pulmonary vein (PV) isolation in paroxysmal AF and additional substrate modification in nonparoxysmal AF patients. Eighty-four patients (12%) with hyperthyroidism history were compared to those without. Euthyroid status was achieved for ≥3 months before ablation in hyperthyroid patients. Patients with hyperthyroid history were associated with older age, more female gender, lower mean right atrial voltage, higher number of PV ectopic foci (1.3 ± 0.4 vs 1.0 ± 0.2, P hyperthyroid patients (7.1% vs 1.6%, P hyperthyroidism was an independent predictor of AF recurrence after single procedure (hazard ratio 2.07, 95% confidence interval 1.27-3.38). AF recurrence rates after multiple procedures were not different between patients with and those without hyperthyroid history. Patients with hyperthyroid history had a significantly higher number of PV ectopies and higher prevalence of non-PV ectopic foci compared to euthyroid patients, which resulted in a higher AF recurrence rate after a single procedure. Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

MK-801 induced amnesia for the elevated plus-maze in mice

Czech Academy of Sciences Publication Activity Database

Hliňák, Zdeněk; Krejčí, I.

2002-01-01

Roč. 131, 1-2 (2002), s. 221-225 ISSN 0166-4328 R&D Projects: GA ČR GA309/00/1644 Institutional research plan: CEZ:AV0Z5011922 Keywords : amnesia * elevated plus-maze * MK-801 Subject RIV: FH - Neurology Impact factor: 2.791, year: 2002

Nogo-A downregulation impairs place avoidance in the Carousel maze but not spatial memory in the Morris water maze

Czech Academy of Sciences Publication Activity Database

Petrásek, Tomáš; Prokopová, Iva; Bahník, Štěpán; Schönig, K.; Berger, S.; Valeš, Karel; Tews, B.; Schwab, M. E.; Bartsch, D.; Stuchlík, Aleš

2014-01-01

Roč. 107, Jan 2014 (2014), s. 42-49 ISSN 1074-7427 R&D Projects: GA ČR(CZ) GCP303/10/J032; GA ČR(CZ) GBP304/12/G069; GA MZd(CZ) NT13386; GA ČR(CZ) GA14-03627S Grant - others:Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR(CZ) M200111204; Univerzita Karlova(CZ) 365911 Institutional support: RVO:67985823 Keywords : Nogo-A * spatial navigation * cognitive coordination * spatial mazes * transgenic rat model Subject RIV: FH - Neurology Impact factor: 3.652, year: 2014

Influence of ablation wavelength and time on optical properties of laser ablated carbon dots

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Isnaeni, Hanna, M. Yusrul; Pambudi, A. A.; Murdaka, F. H.

2017-01-01

Carbon dots, which are unique and applicable materials, have been produced using many techniques. In this work, we have fabricated carbon dots made of coconut fiber using laser ablation technique. The purpose of this work is to evaluate two ablation parameters, which are ablation wavelength and ablation time. We used pulsed laser from Nd:YAG laser with emit wavelength at 355 nm, 532 nm and 1064 nm. We varied ablation time one hour and two hours. Photoluminescence and time-resolved photoluminescence setup were used to study the optical properties of fabricated carbon dots. In general, fabricated carbon dots emit bluish green color emission upon excitation by blue laser. We found that carbon dots fabricated using 1064 nm laser produced the highest carbon dots emission among other samples. The peak wavelength of carbon dots emission is between 495 nm until 505 nm, which gives bluish green color emission. Two hours fabricated carbon dots gave four times higher emission than one hour fabricated carbon dot. More emission intensity of carbon dots means more carbon dots nanoparticles were fabricated during laser ablation process. In addition, we also measured electron dynamics of carbon dots using time-resolved photoluminescence. We found that sample with higher emission has longer electron decay time. Our finding gives optimum condition of carbon dots fabrication from coconut fiber using laser ablation technique. Moreover, fabricated carbon dots are non-toxic nanoparticles that can be applied for health, bio-tagging and medical applications.

Collateral findings during computed tomography scan for atrial fibrillation ablation: Let's take a look around.

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Perna, Francesco; Casella, Michela; Narducci, Maria Lucia; Dello Russo, Antonio; Bencardino, Gianluigi; Pontone, Gianluca; Pelargonio, Gemma; Andreini, Daniele; Vitulano, Nicola; Pizzamiglio, Francesca; Conte, Edoardo; Crea, Filippo; Tondo, Claudio

2016-04-26

The growing number of atrial fibrillation catheter ablation procedures warranted the development of advanced cardiac mapping techniques, such as image integration between electroanatomical map and cardiac computed tomography. While scanning the chest before catheter ablation, it is frequent to detect cardiac and extracardiac collateral findings. Most collateral findings are promptly recognized as benign and do not require further attention. However, sometimes clinically relevant collateral findings are detected, which often warrant extra diagnostic examinations or even invasive procedure, and sometimes need to be followed-up over time. Even though reporting and further investigating collateral findings has not shown a clear survival benefit, almost all the working groups providing data on collateral findings reported some collateral findings eventually coming out to be malignancies, sometimes at an early stage. Therefore, there is currently no clear agreement about the right strategy to be followed.

Investigation of different liquid media and ablation times on pulsed laser ablation synthesis of aluminum nanoparticles

International Nuclear Information System (INIS)

Baladi, Arash; Sarraf Mamoory, Rasoul

2010-01-01

Aluminum nanoparticles were synthesized by pulsed laser ablation of Al targets in ethanol, acetone, and ethylene glycol. Transmission Electron Microscope (TEM) and Scanning Electron Microscope (SEM) images, Particle size distribution diagram from Laser Particle Size Analyzer (LPSA), UV-visible absorption spectra, and weight changes of targets were used for the characterization and comparison of products. The experiments demonstrated that ablation efficiency in ethylene glycol is too low, in ethanol is higher, and in acetone is highest. Comparison between ethanol and acetone clarified that acetone medium leads to finer nanoparticles (mean diameter of 30 nm) with narrower size distribution (from 10 to 100 nm). However, thin carbon layer coats some of them, which was not observed in ethanol medium. It was also revealed that higher ablation time resulted in higher ablated mass, but lower ablation rate. Finer nanoparticles, moreover, were synthesized in higher ablation times.

Investigation of different liquid media and ablation times on pulsed laser ablation synthesis of aluminum nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Baladi, Arash [Materials Engineering Department, Tarbiat Modares University, Jalal Al Ahmad, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of); Sarraf Mamoory, Rasoul, E-mail: rsarrafm@modares.ac.ir [Materials Engineering Department, Tarbiat Modares University, Jalal Al Ahmad, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of)

2010-10-01

Aluminum nanoparticles were synthesized by pulsed laser ablation of Al targets in ethanol, acetone, and ethylene glycol. Transmission Electron Microscope (TEM) and Scanning Electron Microscope (SEM) images, Particle size distribution diagram from Laser Particle Size Analyzer (LPSA), UV-visible absorption spectra, and weight changes of targets were used for the characterization and comparison of products. The experiments demonstrated that ablation efficiency in ethylene glycol is too low, in ethanol is higher, and in acetone is highest. Comparison between ethanol and acetone clarified that acetone medium leads to finer nanoparticles (mean diameter of 30 nm) with narrower size distribution (from 10 to 100 nm). However, thin carbon layer coats some of them, which was not observed in ethanol medium. It was also revealed that higher ablation time resulted in higher ablated mass, but lower ablation rate. Finer nanoparticles, moreover, were synthesized in higher ablation times.

Influence of spatial and temporal manipulations on the anxiolytic efficacy of chlordiazepoxide in mice previously exposed to the elevated plus-maze.

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Holmes, A; Rodgers, R J

1999-11-01

It has been widely reported that the anxiolytic efficacy of benzodiazepines in the elevated plus-maze test is abolished in subjects (rats or mice) that have been given a single prior undrugged experience of the test apparatus. The present series of experiments was designed to further characterise the key experiential determinants of this intriguing phenomenon in Swiss Webster mice. Using a standard 5 min test duration for both trials, Experiment 1 confirmed the anxiolytic efficacy of chlordiazepoxide (CDP; 5-20 mg/kg) in mice naive to the plus-maze, but a virtual elimination of drug effects in animals that had been pre-exposed to the maze 24 h earlier. Experiments 2 and 3 demonstrated that, while extending the duration of initial exposure to 10 min did not prevent the loss of CDP (10 mg/kg) efficacy in a standard-duration second trial, increasing the duration of both trials reinstated an anxiolytic profile for the compound. Finally, although trial 1 confinement to an open arm did not compromise CDP efficacy when animals were subsequently allowed to freely explore the maze (Experiment 4), closed arm confinement during initial exposure abolished the drug's anxiolytic action upon retest (Experiment 5). In contrast to previous findings in rats, these data suggest that the experientially induced loss of benzodiazepine efficacy in the mouse plus-maze depends rather critically upon prior discovery and exploration of relatively safe areas of the maze (i.e. closed arms). Results are discussed in relation to the hypothesis that the absence of an anxiolytic response to benzodiazepines in plus-maze-experienced subjects reflects the acquisition of an open arm phobia during trial 1.

Long-term results after CT-guided percutaneous ethanol ablation for the treatment of hyper functioning adrenal disorders

International Nuclear Information System (INIS)

Frenk, Nathan Elie; Sebastianes, Fernando; Lerario, Antonio Marcondes; Fragoso, Maria Candida Barisson Villares; Mendonca, Berenice Bilharinho

2016-01-01

Objectives: To evaluate the safety and long-term efficacy of computed tomography-guided percutaneous ethanol ablation for benign primary and secondary hyper functioning adrenal disorders. Method: We retrospectively evaluated the long-term results of nine patients treated with computed tomography guided percutaneous ethanol ablation: eight subjects who presented with primary adrenal disorders, such as pheochromocytoma, primary macro nodular adrenal hyperplasia and aldosterone-producing adenoma, and one subject with Cushing disease refractory to conventional treatment. Eleven sessions were performed for the nine patients. The patient data were reviewed for the clinical outcome and procedure-related complications over ten years. Results: Patients with aldosterone-producing adenoma had clinical improvement: symptoms recurred in one case 96 months after ethanol ablation, and the other patient was still in remission 110 months later. All patients with pheochromocytoma had clinical improvement but were eventually submitted to surgery for complete remission. No significant clinical improvement was seen in patients with hypercortisolism due to primary macro nodular adrenal hyperplasia or Cushing disease. Major complications were seen in five of the eleven procedures and included cardiovascular instability and myocardial infarction. Minor complications attributed to sedation were seen in two patients. Conclusion: Computed tomography-guided ethanol ablation does not appear to be suitable for the long-term treatment of hyper functioning adrenal disorders and is not without risks. (author)

Long-term results after CT-guided percutaneous ethanol ablation for the treatment of hyper functioning adrenal disorders

Energy Technology Data Exchange (ETDEWEB)

Frenk, Nathan Elie; Sebastianes, Fernando; Lerario, Antonio Marcondes; Fragoso, Maria Candida Barisson Villares; Mendonca, Berenice Bilharinho [Universidade de Sao Paulo (USP), SP (Brazil). Faculdade de Medicina; Menezes, Marcos Roberto de, E-mail: menezesmr@gmail.com [Instituto do Cancer do Estado de Sao Paulo, SP (Brazil)

2016-10-15

Objectives: To evaluate the safety and long-term efficacy of computed tomography-guided percutaneous ethanol ablation for benign primary and secondary hyper functioning adrenal disorders. Method: We retrospectively evaluated the long-term results of nine patients treated with computed tomography guided percutaneous ethanol ablation: eight subjects who presented with primary adrenal disorders, such as pheochromocytoma, primary macro nodular adrenal hyperplasia and aldosterone-producing adenoma, and one subject with Cushing disease refractory to conventional treatment. Eleven sessions were performed for the nine patients. The patient data were reviewed for the clinical outcome and procedure-related complications over ten years. Results: Patients with aldosterone-producing adenoma had clinical improvement: symptoms recurred in one case 96 months after ethanol ablation, and the other patient was still in remission 110 months later. All patients with pheochromocytoma had clinical improvement but were eventually submitted to surgery for complete remission. No significant clinical improvement was seen in patients with hypercortisolism due to primary macro nodular adrenal hyperplasia or Cushing disease. Major complications were seen in five of the eleven procedures and included cardiovascular instability and myocardial infarction. Minor complications attributed to sedation were seen in two patients. Conclusion: Computed tomography-guided ethanol ablation does not appear to be suitable for the long-term treatment of hyper functioning adrenal disorders and is not without risks. (author)

Value of Nonrigid Registration of Pre-Procedure MR with Post-Procedure CT After Radiofrequency Ablation for Hepatocellular Carcinoma

Energy Technology Data Exchange (ETDEWEB)

Park, Juil; Lee, Jeong Min, E-mail: jmlshy2000@gmail.com, E-mail: jmsh@snu.ac.kr; Lee, Dong Ho; Joo, Ijin; Yoon, Jeong Hee [Seoul National University Hospital, Department of Radiology (Korea, Republic of); Park, Jin Young [Dongnam Institute of Radiological and Medical Sciences, Department of Radiology (Korea, Republic of); Klotz, Ernst [Siemens Healthineers, Computed Tomography (Germany)

2017-06-15

PurposeTo evaluate the value of pre-radiofrequency ablation (RFA) MR and post-RFA CT registration for the assessment of the therapeutic response of hepatocellular carcinoma (HCC).Materials and MethodsA total of 178 patients with single HCC who received RFA as an initial treatment and had available pre-RFA MR and post-RFA CT images were included in this retrospective study. Two independent readers (one experienced radiologist, one inexperienced radiologist) scored the ablative margin (AM) of treated tumors on a four-point scale (1, residual tumor; 2, incomplete AM; 3, borderline AM; 4, sufficient AM), in two separate sessions: (1) visual comparison between pre-and post-RFA images; (2) with addition of nonrigid registration for pre- and post-RFA images. Local tumor progression (LTP) rates between low-risk (response score, 3–4) and high-risk groups (1–2) were analyzed using the Kaplan–Meier method at each interpretation session.ResultsThe patients’ reassignments after using the registered images were statistically significant for inexperienced reader (p < 0.001). In the inexperienced reader, LTP rates of low- and high-risk groups were significantly different with addition of registered images (session 2) (p < 0.001), but not significantly different in session 1 (p = 0.101). However, in the experienced reader, LTP rates of low- and high-risk groups were significantly different in both interpretation sessions (p < 0.001). Using the registered images, the cumulative incidence of LTP at 2 years was 3.0–6.6%, for the low-risk group, and 18.6–27.8% for the high-risk group.ConclusionRegistration between pre-RFA MR and post-RFA CT images may allow better assessment of the therapeutic response of HCC after RFA, especially for inexperienced radiologists, helping in the risk stratification for LTP.

Pulmonary venous thrombosis secondary to radiofrequency ablation of the pulmonary veins

Directory of Open Access Journals (Sweden)

Raquel López-Reyes

Full Text Available Background: Pulmonary Vein Thrombosis (PVT is a rare and underdiagnosed entity produced by local mechanical nature mechanisms, vascular torsion or direct injury to the vein. PVT has been described in clinical cases or small multicenter series mainly in relation to pulmonary vein stenosis, metastatic carcinoma, fibrosing mediastinitis, as an early surgical complication of lung transplantation lobectomy and radiofrequency ablation performed in patients with atrial fibrillation, although in some cases the cause is not known. Case: We report the case of a 57 years old male with history of atrial fibrillation treated by radiofrequency ablation who was admitted in our center because of a two-week history of consistent pleuritic pain in the left hemithorax and low-grade hemoptysis and a lung consolidation treated as a pneumonia with antibiotic but not responding to medical therapy. In view of the poor evolution of the patient, computed tomography angiography was performed with findings of PVT and secondary venous infarction and anticoagulation therapy was optimized. At the end, pulmonary resection was performed due to hemorrhagic recurrence. Conclusion: PVT remains a rare complication of radiofrequency ablation and other procedures involving pulmonary veins. Clinical suspicion and early diagnosis is crucial because is a potentially life-threatening entity. Keywords: Venous thrombosis, Atrial fibrilation, Radiofrequency ablation, Hemoptysis, Lung consolidation, Lung infarction, Lung resection surgery

Activity-based cost analysis of hepatic tumor ablation using CT-guided high-dose rate brachytherapy or CT-guided radiofrequency ablation in hepatocellular carcinoma.

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