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Sample records for ablative maze procedure

  1. Design and evaluation of a transesophageal HIFU probe for ultrasound-guided cardiac ablation: simulation of a HIFU mini-maze procedure and preliminary ex vivo trials.

    Science.gov (United States)

    Constanciel, Elodie; N'Djin, W Apoutou; Bessière, Francis; Chavrier, Françoise; Grinberg, Daniel; Vignot, Alexandre; Chevalier, Philippe; Chapelon, Jean Yves; Lafon, Cyril

    2013-09-01

    Atrial fibrillation (AF) is the most frequent cardiac arrhythmia. Left atrial catheter ablation is currently performed to treat this disease. Several energy sources are used, such as radio-frequency or cryotherapy. The main target of this procedure is to isolate the pulmonary veins. However, significant complications caused by the invasive procedure are described, such as stroke, tamponade, and atrioesophageal fistula, and a second intervention is often needed to avoid atrial fibrillation recurrence. For these reasons, a minimally-invasive device allowing performance of more complex treatments is still needed. High-intensity focused ultrasound (HIFU) can cause deep tissue lesions without damaging intervening tissues. Left atrial ultrasound-guided transesophageal HIFU ablation could have the potential to become a new ablation technique. The goal of this study was to design and test a minimally-invasive ultrasound-guided transesophageal HIFU probe under realistic treatment conditions. First, numerical simulations were conducted to determine the probe geometry, and to validate the feasibility of performing an AF treatment using a HIFU mini-maze (HIFUMM) procedure. Then, a prototype was manufactured and characterized. The 18-mm-diameter probe head housing contained a 3-MHz spherical truncated HIFU transducer divided into 8 rings, with a 5-MHz commercial transesophageal echocardiography (TEE) transducer integrated in the center. Finally, ex vivo experiments were performed to test the impact of the esophagus layer between the probe and the tissue to treat, and also the influence of the lungs and the vascularization on lesion formation. First results show that this prototype successfully created ex vivo transmural myocardial lesions under ultrasound guidance, while preserving intervening tissues (such as the esophagus). Ultrasound-guided transesophageal HIFU can be a good candidate for treatment of AF in the future. PMID:24658718

  2. Postoperative metabolic acidosis following the minimally invasive radiofrequency maze procedure

    OpenAIRE

    Raymond Patrick Hom; Anna Dubovoy; Elizabeth Jewell; Milo Engoren

    2016-01-01

    Purpose: Atrial fibrillation (AF) is the most common arrhythmia treated in the world. While medical treatment with antiarrhythmic drugs remains the primary treatment modality, symptomatic refractory AF often requires treatment with a catheter or surgical ablation. One minimally invasive therapy is the Mini-Maze procedure, which utilizes epicardial radiofrequency ablation via a subxiphoid approach to rid the heart of arrhythmogenic atrial foci without a median sternotomy or cardiopulmonary byp...

  3. Surgical Radiofrequency MAZE III Ablation for Treatment of Atrial Fibrillation During Open Heart Surgery

    Directory of Open Access Journals (Sweden)

    Fariborz Akbarzadeh

    2006-05-01

    Full Text Available Background: Atrial fibrillation is a common arrhythmia in patients with rheumatic mitral and other valve diseases who are candidates for valve repair surgeries. Conversion of rhythm to sinus has positive effects on quality of life and lower use of medications. The aim of this clinical study was to evaluate the effectiveness of the radiofrequency ablation Maze III procedure in the treatment of atrial fibrillation associated with rheumatic heart valve disease. Methods: We applied a modified Cox III Maze procedure using radiofrequency ablation in the treatment of atrial fibrillation associated with rheumatic heart valve disease and evaluated the outcome of 20 patients of atrial fibrillation associated rheumatic valve disease who underwent radiofrequency ablation Maze III procedure plus heart valve surgery. Demographic, echocardiographic, Electrocardiographic and Doppler study data were calculated before surgery, six month and one year after surgery.. Results: No perioperative deaths occurred in the study group. Duration of additional time for doing radiofrequency ablation was about 22 minutes. Freedom from atrial fibrillation was 85% and 75% at six months and one year follow-up respectively... Conclusions: The addition of the radiofrequency ablation Maze procedure to heart valve surgery is safe and effective in the treatment of atrial fibrillation associated with rheumatic heart valve disease.

  4. 改良迷宫双极射频消融术治疗心房颤动的早期疗效分析%The early outcome of atrial fibrillation treated by bipolar radiofrequency ablation modified maze procedure

    Institute of Scientific and Technical Information of China (English)

    邓元子; 李韬; 胡楝; 刘超; 余观水; 曹永科

    2013-01-01

    Objective:To evaluate the early outcomes of bipolar radiofrequency ablation modified maze procedure for treating atrial fibrillation in valve replacement.Methods:From September 2011 to September 2012,bipolar radiofrequency was used to perform modified maze procedure for 39 patients with atrial fibrillation in valve replacement,including male 16 cases,female 23 cases.The age distribution was from 23 to 69 years.28 cases of mitral valve replacement,11 cases of double valve replacement,add tricuspid valve plasty in 26 cases.ECG was performed preoperatively,at ICU,and at discharge,after 1 month,3 months to determine the early effect of bipolar radiofrequency ablation modified maze procedure.89 patients who had received valve replacement by the same surgeon in the same period were divided into control group.Results:In the radiofrequency ablation group,34 patients was returned to sinus rhythm while atrial fibrillation remained in 3 patients at discharge (atrial fibrillation elimination coefficient was 87.1%).The patients took amiodarone for 3 months.At 3-month follow-up,35 patients remained in sinus rhythm(Atrial fibrillation elimination coefficient was 89.7%).The total drainage of the first 3 postoperative days statistics in Ablation group was more than control group (P <0.05).The CPB time of Ablation group was more than control group (P < 0.05).There was no significant difference in surgical complications between Ablation group and control group(P > 0.05).Conclusion:Bipolar radiofrequency ablation modified maze procedure is a safe and simple method for treating atrial fibrillation.The early outcome is very good.%目的:分析瓣膜置换同期行改良迷宫双极射频消融术治疗合并心房颤动的早期疗效.方法:2011年9月至2012年9月,39例患者在瓣膜置换术同期采用双极射频消融系统,取改良迷宫手术路径治疗心房颤动.其中男性16例,女性23例,年龄23 ~69岁,二尖瓣置换28例,双瓣膜置换11

  5. Postoperative metabolic acidosis following the minimally invasive radiofrequency maze procedure

    Directory of Open Access Journals (Sweden)

    Raymond Patrick Hom

    2016-01-01

    Full Text Available Purpose: Atrial fibrillation (AF is the most common arrhythmia treated in the world. While medical treatment with antiarrhythmic drugs remains the primary treatment modality, symptomatic refractory AF often requires treatment with a catheter or surgical ablation. One minimally invasive therapy is the Mini-Maze procedure, which utilizes epicardial radiofrequency ablation via a subxiphoid approach to rid the heart of arrhythmogenic atrial foci without a median sternotomy or cardiopulmonary bypass. The goal of this retrospective cohort study was to identify clinical factors associated with metabolic acidosis following the Mini-Maze procedure. Materials and Methods: After Institutional Review Board approval, we studied patients undergoing the Mini-Maze procedure, off-pump coronary artery bypass grafting or patients conventional Cox-Maze on cardiopulmonary bypass. The first base deficit value obtained in the Intensive Care Unit was used as a measure of metabolic acidosis. Using logistic regression with Akaike information criteria, we analyzed preoperative, intraoperative, and postoperative data to determine the factors associated with changes in base deficit. Results: A multivariable model using stepwise selection demonstrated that diabetes mellitus and weight were associated with a decrease in the base deficit by 2.87 mEq/L (95% CI: −5.55-−0.19 and 0.04 mEq/L (95%CI: −0.08, 0.004, respectively. Furthermore, creatinine was associated with a 1.57 mEq/L (95% CI: 0.14, 2.99 increase in the base deficit. Conclusion: The Mini-Maze procedure was not associated with postoperative metabolic acidosis. Instead, nondiabetic patients and patients with higher creatinine were associated with greater base deficits after undergoing cardiac surgery.

  6. Surgical Radiofrequency MAZE III Ablation for Treatment of Atrial Fibrillation During Open Heart Surgery

    OpenAIRE

    Fariborz Akbarzadeh; Rezayat Parvizi

    2006-01-01

    Background: Atrial fibrillation is a common arrhythmia in patients with rheumatic mitral and other valve diseases who are candidates for valve repair surgeries. Conversion of rhythm to sinus has positive effects on quality of life and lower use of medications. The aim of this clinical study was to evaluate the effectiveness of the radiofrequency ablation Maze III procedure in the treatment of atrial fibrillation associated with rheumatic heart valve disease. Methods: We applied a modified Cox...

  7. 永久性心房颤动外科双极射频消融术的效果%Outcomes of Maze Procedure Using Bipolar Radiofrequency Ablation for Surgical Treatment of Permanent Atrial Fibrillation

    Institute of Scientific and Technical Information of China (English)

    杨嵩; 张希; 唐白云; 殷胜利

    2012-01-01

    Objective To summarize the clinical outcomes of maze procedure using bipolar radiofrequency ablation accompanied with valve replacement for the surgical treatment of permanent atrial fibrillation (AF) and rheumatic valve diseases. Methods A total of 124 patients with permanent AF and rheumatic valves diseases undergoing surgical treatment from March 2006 to October 2010 in the First Affiliated Hospital of Sun Yat-sen University were randomly divided into ablation group and control group using coin method with 62 patients in each group. The mean atrial fibrillation duration was (56.1+47.1) months in ablation group, and patients in this group underwent maze procedure using bipolar radiofrequency ablation and valve replacement. The mean atrial fibrillation duration was (43. 8+25.6) months in control group, and patients in this group underwent only valve replacement. Demographic characteristics, cardiopulmonary bypass (CPB) time, aortic cross-clamping (ACC) time, mechanical ventilation time, intensive care unit (ICU) length of stay, postoperative complications and follow-up outcomes were compared between the two groups. Results The demographic characteristics of the two groups were not statistically different (P > 0.05). The CPB time and ACC time between the two groups were not statistically different (P > 0.05). The postoperative hospital stay of ablation group was significantly longer than that of control group (15.8+6.1 d vs. 12.9+3.1 d, P=0.001). No patient needed permanent pacemaker implantation in either group. Postoperative ejection fraction of ablation group was significantly higher than that of control group (59.6%±9.2% vs. 55.5%±5.4%, P < 0.01). The rate of sinus rhythm maintenance at 6 months, 12 months, 18 months, 24 months during follow-up in ablation group were 88.5%, 87.5%, 87.1% and 82.4% respectively, 3. 3%, 2.2%, 0.0%, and 0.0% in control group respectively, which was statistically different between the two groups (P < 0.05). Conclusion Maze

  8. Paracardioscopic Ex-Maze

    Medline Plus

    Full Text Available ... The Ex-Maze procedure, which we have been working on for quite some time, is a procedure ... slide, that demonstrates how the VisiTrax ablation device works. It's a suction device. It actually sucks up ...

  9. Minimally invasive Cox Mazeablation procedure performed entirely by bipolar clamp concomitant to mitral valve surgery through right lateral minithoracotomy%微创右胸切口二尖瓣手术同期双极钳Cox迷宫Ⅳ手术及中期结果

    Institute of Scientific and Technical Information of China (English)

    姜兆磊; 马南; 梅举; 丁芳宝; 黄健兵; 刘浩; 沈赛娥

    2015-01-01

    目的 探讨经微创右胸切口二尖瓣手术同期应用双极射频消融钳行Cox MazeⅣ(迷宫Ⅳ)手术治疗房颤的方法,评价其治疗效果.方法 2012年6月至2015年1月,微创右胸切口二尖瓣手术同期应用双极射频消融钳作Cox迷宫Ⅳ手术69例,男43例,女26例;年龄52~71岁.房颤病程1.5~13.0年,均为长程持续性房颤.左心房直径42~ 60 mm;左心室直径43~ 66 mm;左心室射血分数0.45~0.67.二尖瓣风湿性病变41例,退行性病变28例;合并中度以上功能性三尖瓣关闭不全16例.结果 69例顺利完成心脏瓣膜手术及Cox迷宫Ⅳ手术,无转为正中开胸手术者.其中二尖瓣置换41例,同期行三尖瓣成形10例;二尖瓣成形28例,同期行三尖瓣成形6例.体外循环94~ 161 min,平均(130.3±17.7) min;主动脉阻断70~ 125 min,平均(91.8±12.7) min.围术期无死亡,无置入永久起搏器者.术后早期并发症包括低心排血量综合征3例,急性肾功能不全1例,肺部感染1例.住院7~16天,平均(9.8±3.3)天.出院时,65例(65/69,94.2%)维持窦性心律.术后随访6~ 37个月,平均(21.0±8.6)个月,62例(62/69,89.9%)维持窦性心律,术后2年累计窦性心律维持率为(85.1±5.8)%.结论 经微创右胸切口行二尖瓣手术时,同期应用双极射频消融钳作Cox迷宫Ⅳ术治疗房颤安全、有效,早、中期效果满意.%Objective Objectives: To introduce the technique of performing minimally invasive concomitant Cox Mazeablation procedure entirely by bipolar clamp through right lateral minithoracotomy for patients with atrial fibrillation(AF) associated with mitral valve diseases.Methods Sixty nine patients with mitral valve disease and long-standing persistent AF received minimally invasive Cox Mazeablation procedure combined with mitral valve surgery from June 2012 to January 2015.The etiology of mitral valve disease was rheumatic(41 cases) and degenerative(28 cases).Age at operation ranged from 52

  10. DSTYK kinase domain ablation impaired the mice capabilities of learning and memory in water maze test.

    Science.gov (United States)

    Li, Kui; Liu, Ji-Wei; Zhu, Zhi-Chuan; Wang, Hong-Tao; Zu, Yong; Liu, Yong-Jie; Yang, Yan-Hong; Xiong, Zhi-Qi; Shen, Xu; Chen, Rui; Zheng, Jing; Hu, Ze-Lan

    2014-01-01

    DSTYK (Dual serine/threonine and tyrosine protein kinase) is a putative dual Ser/Thr and Tyr protein kinase with unique structural features. It is proposed that DSTYK may play important roles in brain because of its high expression in most brain areas. In the present study, a DSTYK knockout (KO) mouse line with the ablation of C-terminal of DSTYK including the kinase domain was generated to study the physiological function of DSTYK. The DSTYK KO mice are fertile and have no significant morphological defects revealed by Nissl staining compared with wildtype mice. Open field test and rotarod test showed there is no obvious difference in basic motor and balance capacity between the DSTYK homozygous KO mice and DSTYK heterozygous KO mice. In water maze test, however, the DSTYK homozygous KO mice show impaired capabilities of learning and memory compared with the DSTYK heterozygous KO mice.

  11. The totally thoracoscopic left atrial maze procedure for the treatment of atrial fibrillation.

    Science.gov (United States)

    van Laar, Charlotte; Geuzebroek, Guillaume S C; Hofman, Frederik N; Van Putte, Bart P

    2016-01-01

    The totally thoracoscopic left atrial maze (TT-maze) is a recent, minimally invasive surgical procedure for the treatment of atrial fibrillation, with promising results in terms of freedom from atrial fibrillation. The TT-maze consists of a bilateral, epicardial pulmonary vein isolation with the creation of a box using radiofrequency and exclusion of the left atrial appendage (LAA). In addition, the box is connected with the base of the LAA and furthermore with the mitral annulus with the so-called trigonum line. In this report, we describe our surgical approach and short-term results. PMID:26993056

  12. Modified Maze lines plus pulmonary vein isolation created by radiofrequency catheter ablation on the atrial wall to treat atrial fibrillation in elderly

    Institute of Scientific and Technical Information of China (English)

    Caiyi LU; Shiwen WANG; Xinping DU; Yinglong HOU; Qiao XUE; Xinli WU; Rui CHEN; Peng LIU

    2005-01-01

    Objective To evaluate the effect of modified Maze lines plus pulmonary vein (PV) isolation created by radiofrequency catheter ablation (RFCA) on atrial wall guided by a novel geometry mapping system in the treatment of elderly patients with paroxysmal atrial fibrillation (PAF). Methods After regular electrophysiological study, transseptal punctures were achieved twice with Swartz L1 and R1 sheaths. PV angiographies were conducted to evaluate their orifices and branches. A balloon electrode array catheter with 64 electrodes was put in the middle of the left atrium. Atrium geometry was constructed using Ensite 3000 Navx system. Two RFCA lesion loops and three lines (modified Maze) were created on left and right atrial walls. Each lesion point was ablated for 30 seconds with preset temperature 50 (ae) and energy 30W. The disappearance or 80% decrease of the amplitude of target atrial potential and 10 to 20(|), decrease of ablation impedance were used as an index of effective ablation. Results A total of 11 patients (7 male and 4 female, mean age, 68.7±5.1 years) were enrolled. PAF history was 7.9±4.5 years. PAF could not be prevented by mean 3.1±1.6 antiarrhythmic agents in 6.3±3.4 years. None of the patients had complications with structural heart disease or stroke. Left atrial diameter was 41.3±3.6 mm and LVEF was 59.2±3.7% on echocardiography. Two loops and three lines were completed with 67.8±13.1 (73-167) lesion points. Altogether 76-168 (89.4±15.3) lesion points were created in each patient. PAF could not be provoked by rapid burst pacing up to 600 beat per minute delivered from paroxysmal coronary sinus electrode pair.Complete PV electrical isolation was confirmed by three-dimensional activation mapping. Mean procedure time was 2.7±0.6 hours and fluoroscopy time was 17.8±9.4 minutes. Patients were discharged with oral aspirin and without antiarrhythmic agents. During follow up of 6.5±1.8 months, seven patients were PAF symptom free (63.6%). PAF

  13. Outcome of Cox Maze procedure concomitant with mitral valve operation in treatment of atrial fibrillation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Sai; CHEN Ru-kun; DONG Ai-qiang; WANG Yong-qin; CHEN Suo-cheng; LI Zhi-jun

    2006-01-01

    @@ Atrial fibrillation (AF) is fairly common in patients with chronic mitral valve disease and a markedly dilated left atrium. These patients rarely return to sinus rhythm spontaneously, even after a successful mitral valve operation. The Maze procedure,developed by Cox and associates,1-5 has been used in patients undergoing a mitral valve operation.Restoration of normal sinus rhythm and atrial contraction in such patients have been reported by some groups. This study will summarize retrospectively a group of patients who underwent the Cox Maze procedure for the treatment of AF associated with rheumatic mitral valve disease in China.

  14. Electrocardiographic nature of restored sinus rhythm after Cox maze procedure in patients with chronic atrial fibrillation who also had other cardiac surgery.

    OpenAIRE

    Kamata, J.; Nakai, K.; Chiba, N; Hosokawa, S.; Sato, Y.; Nasu, M.; Sasaki, T.; Kitahara, H; Izumoto, H.; Yagi, Y; Itoh, C.; Hiramori, K; Kawazoe, K

    1997-01-01

    OBJECTIVE: To characterise heart rate variability and high frequency components of restored sinus rhythm after the maze procedure. The maze procedure for chronic atrial fibrillation may prevent thrombotic events and improve the quality of life. However, the electrocardiographic nature of restored sinus rhythm after the maze procedure has not been fully elucidated. PATIENTS AND METHODS: Between March 1993 and August 1995, 104 consecutive patients undergoing the maze procedure in combination wi...

  15. Radiofrequency ablation of hepatic tumors: lessons learned from 3000 procedures.

    Science.gov (United States)

    Rhim, Hyunchul; Lim, Hyo K; Kim, Young-sum; Choi, Dongil; Lee, Won Jae

    2008-10-01

    Radiofrequency ablation has been accepted as the most popular local ablative therapy for unresectable malignant hepatic tumors. For 9 years from April 1999, we performed 3000 radiofrequency ablation procedures for hepatic tumors in our institution. Our results on the safety (mortality, 0.15%/patient) and therapeutic efficacy (5-year survival rate, 58%) are similar to those of previous studies reported, supporting the growing evidence of a clear survival benefit, excellent results for local tumor control and improved quality of life. The most important lesson learned from our 3000 procedures is that the best planning, safe ablation and complete ablation are key factors for patient outcome. Furthermore, multimodality treatment is the best strategy for recurrent hepatocellular carcinoma encountered after any kind of first-line treatment.

  16. The effects of apparatus design and test procedure on learning and memory performance of C57BL/6J mice on the Barnes maze.

    Science.gov (United States)

    O'Leary, Timothy P; Brown, Richard E

    2012-01-30

    The Barnes maze is a visuo-spatial learning and memory test originally designed for use with rats, and later adapted for use with mice. The Barnes maze design and test procedure vary across studies using mice, but the effects of variation in Barnes maze design and test procedure on learning and memory in mice have not yet been investigated. Therefore the present experiment investigates whether test procedures, such as the number of habituation trials and parameters of the probe trial (correct zone size and trial length) influence learning and memory performance on three Barnes maze designs that differed in size and the presence of a wall with intra-maze visual cues. Performance was compared across the three mazes to determine how apparatus design influences visuo-spatial cue use. The number of habituation trials and parameters of the probe trial had small effects on learning and memory performance. Apparatus design, had little effect on acquisition performance but had a significant effect on memory performance. Mice on a maze with a small diameter, external wall and intra-maze visual cues had very poor visuo-spatial memory relative to mice tested on small and large diameter mazes without a wall or intra-maze visual cues. Assessment of visuo-spatial cue use indicated that mice do not rely on visuo-spatial cues to locate the escape hole on the small-diameter maze with a wall and intra-maze visual cues, but show reliable visuo-spatial cue use on small or large diameter mazes with no wall. These results indicate that apparatus design influences search strategy use and memory performance on the Barnes maze, and that including a wall around the edge of the Barnes maze decreases visuo-spatial cue use.

  17. Optimizing safety and efficacy of catheter ablation procedures

    NARCIS (Netherlands)

    F. Akca (Ferdi)

    2015-01-01

    markdownabstractAbstract In this thesis new developments in the field of invasive electrophysiology are studied and discussed. The aim of this work is to find strategies to optimize safety and efficacy of catheter ablation procedures. The most important developments that are studied in this thesis

  18. Learning-related coordination of striatal and hippocampal theta rhythms during acquisition of a procedural maze task

    OpenAIRE

    DeCoteau, William E.; Thorn, Catherine; Gibson, Daniel J.; Courtemanche, Richard; Mitra, Partha; Kubota, Yasuo; Graybiel, Ann M.

    2007-01-01

    The striatum and hippocampus are conventionally viewed as complementary learning and memory systems, with the hippocampus specialized for fact-based episodic memory and the striatum for procedural learning and memory. Here we directly tested whether these two systems exhibit independent or coordinated activity patterns during procedural learning. We trained rats on a conditional T-maze task requiring navigational and cue-based associative learning. We recorded local field potential (LFP) acti...

  19. Wolf Mini-Maze procedure for atrial fibrillation%Wolf Mini-Maze手术治疗单纯性心房颤动

    Institute of Scientific and Technical Information of China (English)

    刘胜中; 曾富春; 丛伟

    2013-01-01

    目的 总结Wolf Mini-Maze手术治疗单纯性心房颤动的临床经验,并评价其安全性和疗效.方法 自2010年11月起,我科采用AtriCureTM干式双极微创射频消融系统经胸腔镜对2例单纯性心房颤动患者施行了双侧肺静脉隔离及左心耳切除术.结果 2例手术过程顺利,消融术后即刻恢复窦性心律.术后随访3 ~17个月,维持窦性心律,无卒中及其它并发症发生.结论 Wolf Mini-Maze手术治疗单纯性心房颤动具有微创、简单、安全、高效的特点,值得推广.%Objective To summarize the experience of Wolf Mini-Maze procedure for atrial fibrillation, and to evaluate its safety and effect. Methods From November 2010, 2 patients with atrial fibrillation accepted thoracoscopic off-pump bilateral epicardial pulmonary vein isolation by using an AtriCure bipolar radiofrequency ablation device and endoscopic excision of the left atrial appendage by using a EZ-45G stapler. Results The operation was performed successfully. The patients were in sinus rhythm immediately after procedure, and still in sinus rhythm during following-up period (from 3 to 17 months). No stroke and other complications were found during following-up period. Conclusion Wolf Mini-Maze procedure is minimally invasive, simple, safe and effective. It is a promising procedure in atrial fibrillation treatment.

  20. Factors influencing the efficacy of radiofrequency ablation Maze procedure combined with open-heart operation for treatment of atrial fibrillation%影响心内直视手术加射频消融迷宫术治疗心房颤动疗效的因素

    Institute of Scientific and Technical Information of China (English)

    王邵华; 王春生

    2008-01-01

    目的 分析影响心内直视手术加射频(RF)消融迷宫(Maze)术治疗心房颤动(AF)疗效的因素.方法 连续收集58例接受心内直视手术加RF消融MazeⅢ术患者的临床资料并随访患者的心电图,运用COX回归分析确定影响手术疗效的独立因素.结果 本组失访3例,随访率为94.8%(55/58),随访6~28个月,平均随访时间为(14.2±6.5)个月,最后1次随访中窦性心律恢复率为76.4%(42/55).术前AF病程>4年是影响心内直视手术加RF消融Maze术治疗AF疗效的独立危险因素(P=0.025).结论 AF病程影响心内直视手术加RF消融Maze术治疗AF的疗效,AF病程越长,手术效果越差.

  1. Learning-related coordination of striatal and hippocampal theta rhythms during acquisition of a procedural maze task.

    Science.gov (United States)

    DeCoteau, William E; Thorn, Catherine; Gibson, Daniel J; Courtemanche, Richard; Mitra, Partha; Kubota, Yasuo; Graybiel, Ann M

    2007-03-27

    The striatum and hippocampus are conventionally viewed as complementary learning and memory systems, with the hippocampus specialized for fact-based episodic memory and the striatum for procedural learning and memory. Here we directly tested whether these two systems exhibit independent or coordinated activity patterns during procedural learning. We trained rats on a conditional T-maze task requiring navigational and cue-based associative learning. We recorded local field potential (LFP) activity with tetrodes chronically implanted in the caudoputamen and the CA1 field of the dorsal hippocampus during 6-25 days of training. We show that simultaneously recorded striatal and hippocampal theta rhythms are modulated differently as the rats learned to perform the T-maze task but nevertheless become highly coherent during the choice period of the maze runs in rats that successfully learned the task. Moreover, in the rats that acquired the task, the phase of the striatal-hippocampal theta coherence was modified toward a consistent antiphase relationship, and these changes occurred in proportion to the levels of learning achieved. We suggest that rhythmic oscillations, including theta-band activity, could influence not only neural processing in cortico-basal ganglia circuits but also dynamic interactions between basal ganglia-based and hippocampus-based forebrain circuits during the acquisition and performance of learned behaviors. Experience-dependent changes in coordination of oscillatory activity across brain structures thus may parallel the well known plasticity of spike activity that occurs as a function of experience. PMID:17372196

  2. Sinus node function after cardiac surgery : is impairment specific for the maze procedure?

    NARCIS (Netherlands)

    Tuinenburg, AE; Van Gelder, IC; Van Den Berg, MP; Grandjean, JG; Tieleman, RG; Smit, AJ; Huet, RCG; Van Der Maaten, JMAA; Volkers, CP; Ebels, T; Crijns, HJGM

    2004-01-01

    Background: Maze surgery is a final solution for intractable atrial fibrillation (AF), but an adverse effect on postoperative sinus node function has been reported. Whether this also applies to other types of cardiac surgery is unclear. Methods: We assessed postoperative rhythm by means of repeated

  3. Paracardioscopic Ex-Maze

    Medline Plus

    Full Text Available ... because as in every procedure there is a learning curve as we all know. The question is, “ ... procedure done. He told us exactly where the problem was, we did that ablation, that one ablation, ...

  4. Effect of a water-maze procedure on the redox mechanisms in brain parts of aged rats

    Directory of Open Access Journals (Sweden)

    Natalia Andreevna Krivova

    2015-03-01

    Full Text Available The Morris water maze (MWM is a tool for assessment of age-related cognitive deficits. In our work, MWM was used for appraisal of cognitive deficits in 11-month-old rats and investigation of the effect exerted by training in the Morris water maze on the redox mechanisms in rat brain parts. Young adult (3-month-old and aged (11-month-old male rats were trained in the water maze. Intact animals of the corresponding age were used as the reference groups. The level of pro- and antioxidant capacity in brain tissue homogenates was assessed using the chemiluminescence method.Cognitive deficits were found in 11-month-old rats: at the first day of training they showed only 30% of successful MWM trials. However, at the last training day the percentage of successful trials was equal for young adult and aged animals. This indicates that cognitive deficits in aged rats can be reversed by MWM training. Therewith, the MWM spatial learning procedure itself produces changes in different processes of redox homeostasis in 11-month-old and 3-month-old rats as compared to intact animals. Young adult rats showed a decrease in prooxidant capacity in all brain parts, while 11-month-old rats demonstrated an increase in antioxidant capacity in the olfactory bulb, pons + medulla oblongata and frontal lobe cortex. Hence, the MWM procedure activates the mechanisms that restrict the oxidative stress in brain parts. The obtained results may be an argument for further development of the animal training procedures aimed to activate the mechanisms responsible for age-related cognitive deficits. This may be useful not only for the development of training procedures applicable to human patients with age-related cognitive impairments, but also for their rehabilitation.

  5. Paracardioscopic Ex-Maze

    Medline Plus

    Full Text Available ... about doing this procedure. This is actually a video animation of an Ex-Maze procedure done totally ... fibrillation treatment. If we can go to the video, we'll go to the operating room and ...

  6. Validation and scopolamine-reversal of latent learning in the water maze utilizing a revised direct platform placement procedure.

    Science.gov (United States)

    Malin, David H; Schaar, Krystal L; Izygon, Jonathan J; Nghiem, Duyen M; Jabitta, Sikirat Y; Henceroth, Mallori M; Chang, Yu-Hsuan; Daggett, Jenny M; Ward, Christopher P

    2015-08-01

    The Morris water maze is routinely used to explore neurobiological mechanisms of working memory. Humans can often acquire working memory relevant to performing a task by mere sensory observation, without having to actually perform the task followed by reinforcement. This can be modeled in the water maze through direct placement of a rat on the escape platform so that it can observe the location, and then assessing the subject's performance in swimming back to the platform. However, direct placement procedures have hardly been studied for two decades, reflecting a controversy about whether direct placement resulted in sufficiently rapid and direct swims back to the platform. In the present study, utilizing revised training methods, a more comprehensive measure of trajectory directness, a more rigorous sham-trained control procedure and an optimal placement-test interval, rats swam almost directly back to the platform in under 4s, significantly more quickly and directly than sham-trained subjects. Muscarinic cholinergic mechanisms, which are inactivated by scopolamine, are essential to memory for standard learning paradigms in the water maze. This experiment determined whether this would also be true for latent learning. ANOVA revealed significant negative effects of scopolamine on both speed and accuracy of trajectory, as well as significant positive effects of direct placement training vs. sham-training. In a probe trial, placement-trained animals without scopolamine spent significantly more time and path length in the target quadrant than trained rats with scopolamine and sham-trained rats without scopolamine. Scopolamine impairments are likely due to effects on memory, since the same dose had little effect on performance with a visible platform. The revised direct placement model offers a means of further comparing the neural mechanisms of latent learning with those of standard instrumental learning. PMID:26033423

  7. Validation and scopolamine-reversal of latent learning in the water maze utilizing a revised direct platform placement procedure.

    Science.gov (United States)

    Malin, David H; Schaar, Krystal L; Izygon, Jonathan J; Nghiem, Duyen M; Jabitta, Sikirat Y; Henceroth, Mallori M; Chang, Yu-Hsuan; Daggett, Jenny M; Ward, Christopher P

    2015-08-01

    The Morris water maze is routinely used to explore neurobiological mechanisms of working memory. Humans can often acquire working memory relevant to performing a task by mere sensory observation, without having to actually perform the task followed by reinforcement. This can be modeled in the water maze through direct placement of a rat on the escape platform so that it can observe the location, and then assessing the subject's performance in swimming back to the platform. However, direct placement procedures have hardly been studied for two decades, reflecting a controversy about whether direct placement resulted in sufficiently rapid and direct swims back to the platform. In the present study, utilizing revised training methods, a more comprehensive measure of trajectory directness, a more rigorous sham-trained control procedure and an optimal placement-test interval, rats swam almost directly back to the platform in under 4s, significantly more quickly and directly than sham-trained subjects. Muscarinic cholinergic mechanisms, which are inactivated by scopolamine, are essential to memory for standard learning paradigms in the water maze. This experiment determined whether this would also be true for latent learning. ANOVA revealed significant negative effects of scopolamine on both speed and accuracy of trajectory, as well as significant positive effects of direct placement training vs. sham-training. In a probe trial, placement-trained animals without scopolamine spent significantly more time and path length in the target quadrant than trained rats with scopolamine and sham-trained rats without scopolamine. Scopolamine impairments are likely due to effects on memory, since the same dose had little effect on performance with a visible platform. The revised direct placement model offers a means of further comparing the neural mechanisms of latent learning with those of standard instrumental learning.

  8. 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

  9. Paracardioscopic Ex-Maze

    Medline Plus

    Full Text Available ... pattern that he described has been the gold standard to treat all types of atrial fibrillation, but ... A Fib and anti-rhythmic medications. The gold standard at six months, the surgical Maze 3 procedure, ...

  10. Paracardioscopic Ex-Maze

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    Full Text Available ... to the video, we'll go to the operating room and actually see an Ex-Maze procedure ... totally endoscopically. We can see here in the operating room, there are three people at the table, ...

  11. Paracardioscopic Ex-Maze

    Medline Plus

    Full Text Available ... see a live paracardioscopic Ex-Maze procedure for treatment of atrial fibrillation. You'll also learn how ... and often times don't have a good treatment opportunity because of their prolonged disease and because ...

  12. [Maze procedure in a case of dextrocardia with atrial septal defect and persistent left superior vena cava].

    Science.gov (United States)

    Muraoka, Arata; Kawada, Masaaki; Misawa, Yoshio

    2014-08-01

    A 52-year-old man was diagnosed with dextrocardia at the age of 1 year and was asymptomatic until 1 year before admission. He was transferred to our hospital for management of atrial fibrillation. A transthoracic echocardiogram showed dextrocardia with atrial septal defect;moderate tricuspid valve regurgitation; and a large, persistent left superior vena cava. A cardiac catheterization study revealed that pulmonary flow/systemic flow (Qp/Qs) was 3.6 and that pulmonary vascular resistance was 2.5 Wood U·m². Intracardiac repair with tricuspid annuloplasty and a maze procedure was scheduled. When establishing cardiopulmonary bypass, venous drainage was initially obtained from the inferior vena cava and the left superior vena cava, and the small superior vena cava was then directly cannulated after opening the right atrium. The patient's postoperative course was uneventful, and serial electrocardiograms have demonstrated maintenance of normal sinus rhythm for 3.5 years after the operation.

  13. Surgical Ablation of Atrial Fibrillation.

    Science.gov (United States)

    Ramlawi, Basel; Abu Saleh, Walid K

    2015-01-01

    The Cox-maze procedure for the restoration of normal sinus rhythm, initially developed by Dr. James Cox, underwent several iterations over the years. The main concept consists of creating a series of transmural lesions in the right and left atria that disrupt re-entrant circuits responsible for propagating the abnormal atrial fibrillation rhythm. The left atrial appendage is excluded as a component of the Maze procedure. For the first three iterations of the Cox- maze procedure, these lesions were performed using a surgical cut-and-sew approach that ensured transmurality. The Cox-Maze IV is the most currently accepted iteration. It achieves the same lesion set of the Cox- maze III but uses alternative energy sources to create the transmural lesions, potentially in a minimally invasive approach on the beating heart. High-frequency ultrasound, microwave, and laser energy have all been used with varying success in the past. Today, bipolar radiofrequency heat or cryotherapy cooling are the most accepted sources for creating linear lesions with consistent safety and transmurality. The robust and reliable nature of these energy delivery methods has yielded a success rate reaching 90% freedom from atrial fibrillation at 12 months. Such approaches offer a significant long-term advantage over catheter-based ablation, especially in patients having longstanding, persistent atrial fibrillation with characteristics such as dilated left atrial dimensions, poor ejection fraction, and failed catheter ablation. Based on these improved results, there currently is significant interest in developing a hybrid ablation strategy that incorporates the superior transmural robust lesions of surgical ablation, the reliable stroke prevention potential of epicardial left atrial appendage exclusion, and sophisticated mapping and confirmatory catheter-based ablation technology. Such a minimally invasive hybrid strategy for ablation may lead to the development of multidisciplinary "Afib teams" to

  14. Post-procedural Dabigatran Versus Interrupted Warfarin Therapy Following Catheter Ablation for Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Jeffrey Lin, MD; Sharon Shen, MD; Prashant Bhave, MD; Bradley Knight, MD; Martha Bohn, RN, BSN; Evaldas Giedrimas, MD; Taral K. Patel, MD; Alexandru Chicos, MD; Jeffrey Goldberger, MD; Leonard Ilkhanoff, MD, MS; Susan Kim, MD; Albert Lin, MD; Rod Passman, MD, MSCE.

    2014-02-01

    Full Text Available Purpose: Patients undergoing catheter ablation for atrial fibrillation (AF are at a higher risk of thromboembolic events post-procedure and therefore require therapeutic anticoagulation after ablation. Anticoagulation strategies include performing the procedure on or off therapeutic warfarin, though the latter approach requires post-procedure bridging therapy with low molecular-weight heparin (LMWH until a therapeutic INR is achieved. The purpose of this study is to compare the safety and efficacy of post-ablation dabigatran as compared to warfarin with LMWH bridging. Methods: We performed a single-center retrospective analysis of consecutive patients who underwent catheter ablation for AF between January 2010 and December 2012 and received either post-procedure warfarin with a LMWH bridge or dabigatran. Warfarin was started the night of ablation; LMWH was started the next morning and continued until the INR was ≥ 2.0. Dabigatran was started the morning post-ablation. Results: The analysis included 324 patients. Of these, mean age was 60 ± 9 years, 78% were male, 81% had CHADS2 scores of 0 or 1, and 181 (56% received dabigatran post-ablation. Patients who received dabigatran had lower CHADS2 scores and were more likely to be in NYHA Class I. At 30-days post-procedure, there were 0 thromboembolic or bleeding complications in the dabigatran group versus 4 (2.8% in the warfarin group (p=0.037. There were no deaths in either group at 30 days post-ablation. Conclusions: Post-ablation dabigatran appears safe and efficacious compared to an interrupted warfarin strategy with LMWH bridging.

  15. Intermittently “Pre-Excited” ECG after Accessory Pathway Ablation: Unsuccessful Procedure or a Complication?

    Directory of Open Access Journals (Sweden)

    Evgeny Mikhaylov

    2012-01-01

    Full Text Available A 52-year-old woman with previously unsuccessful posteroseptal pathway ablation using radiofrequency energy presented with intermittently occurring short PR followed by a wide QRS complex, and complaining of palpitations with characteristics different from previous history. During a second electrophysiological procedure no signs of preexcitation were found. Ventricular discharges with fusion with sinus beats were revealed, and catheter ablation of premature contractions originating from the proximity to previous accessory pathway was carried out.

  16. Molecular thermometers for potential applications in thermal ablation procedures

    Science.gov (United States)

    Zhegalova, Natalia G.; Aydt, Alex; Wang, Steven T.; Berezin, Mikhail Y.

    2013-02-01

    Thermal ablation is a promising minimally invasive method for treating tumors without surgical intervention. Thermal ablation uses thermal sources such as lasers, radiowaves or focused ultrasound to increase the temperature of the tumor to levels lethal to cancer cells. This treatment based on heat therapy may be problematic as the temperature of the operation site is unknown. To address this problem, we developed optical molecular thermometers that can potentially measure the temperature on a molecular scale and be compatible with in vivo measurements. The thermometers are centered on a combination of two fluorophores emitting in two distinct spectral ranges and having different temperature-dependent emission properties. In this design, a fluorophore with relatively insensitive temperature-dependent fluorescence serves as a reference while another sensitive fluorophore serves as a sensor. We have demonstrated the feasibility of this approach using a coumarin-rhodamine conjugate. The sensitivity of the construct to the clinically relevant ablation temperatures (20-85 °C) was demonstrated in vitro.

  17. 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

    A forced-choice procedure in T-maze designed for the induction of habits was used to induce strong habits in rats. The response choices of rats in 20 free-choice trials were compared after the rats had been subjected to 1 or 200 forced-choice trials to one side of the T-maze. After 200 forced......-choice trials the rats showed a significant (pmaze in the subsequent free-choice trials. The habit was at least as pronounced when analysed over the last 10 free-choice trials as when it was analysed over the first 10 free-choice trials. When the rats were given...... 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....

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

    Science.gov (United States)

    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. PMID:25250831

  19. Intermittent swim stress causes Morris water maze performance deficits in a massed-learning trial procedure that are exacerbated by reboxetine.

    Science.gov (United States)

    Warner, Timothy A; Stafford, Nathaniel P; Rompala, Gregory R; Van Hoogenstyn, Andrew J; Elgert, Emily; Drugan, Robert C

    2013-11-15

    Various animal models of depression have been used to seek a greater understanding of stress-related disorders. However, there is still a great need for research in this area, as many unanswered questions remain. Therefore, we sought to employ a novel animal model of depression known as intermittent swim stress (ISS). In this model, the animal experiences 100 trials of cold water swim stress. ISS has already shown subsequent immobility in the forced swim test (FST), deficits in instrumental and spatial (spaced-trial procedure), and responsiveness to norepinephrine. We are now examining how this will translate in the Morris water maze for rats in a massed-learning trial procedure, and further assessing ISS sensitivity toward norepinephrine selective anti-depressant drugs. The results indicated no difference in cued learning when the platform was visible in the water maze, but a hidden platform task revealed poorer spatial learning for ISS-exposed rats versus controls. In terms of spatial memory, there was a notable ISS-induced deficit 1h after the learning trials, regardless of performance on the previous platform task. Interestingly, the administration of reboxetine interfered with the spatial learning and memory trials for both ISS and CC groups. As a result, ISS exposure compromised spatial learning and memory in the Morris water maze, and norepinephrine does not appear to be a mediator of this deficit. The results demonstrate a key difference in the effects of reboxetine in a massed- vs. spaced-learning trial procedure in the Morris water maze following ISS exposure.

  20. Paracardioscopic Ex-Maze

    Medline Plus

    Full Text Available ... live paracardioscopic Ex-Maze procedure for treatment of atrial fibrillation. You'll also learn how this minimally invasive ... you. 00:01:26 ANDY C. KISER, MD: Atrial fibrillation is a disease that affects a lot of ...

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

    Energy Technology Data Exchange (ETDEWEB)

    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.)

  2. 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 ...... use of three-dimensional mapping systems to decrease X-ray radiation hazards. Digital fluoroscopy with decreased frame rate is not used by approximately one-third of responding centres....

  3. Case report of surgical treatment of abnormal atrial flutter (incisional atrial tachycardia in the patient after mitral valve replacement and radiofrequency modification of Maze procedure

    Directory of Open Access Journals (Sweden)

    Revishvili А. Sh.

    2012-12-01

    Conclusion. This type of tachycardia following after an atrial fibrillation surgery may be considered as a failing transmural myocardial damage during the procedure. The catheter method can be used succesfully unless there are no effects of antiarrhythmic therapy. The catheter method enables not only to verify the disconnection between the left atrial pulmonary veins and left atrium myocardium but also to perform the ablation in zones of the atrial myocardium that are anatomic substrates of post surgery tachyarrhythmias.

  4. Robust tracking of a virtual electrode on a coronary sinus catheter for atrial fibrillation ablation procedures

    Science.gov (United States)

    Wu, Wen; Chen, Terrence; Strobel, Norbert; Comaniciu, Dorin

    2012-02-01

    Catheter tracking in X-ray fluoroscopic images has become more important in interventional applications for atrial fibrillation (AF) ablation procedures. It provides real-time guidance for the physicians and can be used as reference for motion compensation applications. In this paper, we propose a novel approach to track a virtual electrode (VE), which is a non-existing electrode on the coronary sinus (CS) catheter at a more proximal location than any real electrodes. Successful tracking of the VE can provide more accurate motion information than tracking of real electrodes. To achieve VE tracking, we first model the CS catheter as a set of electrodes which are detected by our previously published learning-based approach.1 The tracked electrodes are then used to generate the hypotheses for tracking the VE. Model-based hypotheses are fused and evaluated by a Bayesian framework. Evaluation has been conducted on a database of clinical AF ablation data including challenging scenarios such as low signal-to-noise ratio (SNR), occlusion and nonrigid deformation. Our approach obtains 0.54mm median error and 90% of evaluated data have errors less than 1.67mm. The speed of our tracking algorithm reaches 6 frames-per-second on most data. Our study on motion compensation shows that using the VE as reference provides a good point to detect non-physiological catheter motion during the AF ablation procedures.2

  5. Paracardioscopic Ex-Maze

    Medline Plus

    Full Text Available ... to make the procedure better. Are there other things we can add? We talked about catheter ablations as part of this operation. We're clearly waiting to see how outcomes are, but if someone has atrial fibrillation, that's a good tool to have in our material when treating ...

  6. One-Dimensional Ablation with Pyrolysis Gas Flow Using a Full Newton's Method and Finite Control Volume Procedure

    Science.gov (United States)

    Amar, Adam J.; Blackwell, Ben F.; Edwards, Jack R.

    2007-01-01

    The development and verification of a one-dimensional material thermal response code with ablation is presented. The implicit time integrator, control volume finite element spatial discretization, and Newton's method for nonlinear iteration on the entire system of residual equations have been implemented and verified for the thermochemical ablation of internally decomposing materials. This study is a continuation of the work presented in "One-Dimensional Ablation with Pyrolysis Gas Flow Using a Full Newton's Method and Finite Control Volume Procedure" (AIAA-2006-2910), which described the derivation, implementation, and verification of the constant density solid energy equation terms and boundary conditions. The present study extends the model to decomposing materials including decomposition kinetics, pyrolysis gas flow through the porous char layer, and a mixture (solid and gas) energy equation. Verification results are presented for the thermochemical ablation of a carbon-phenolic ablator which involves the solution of the entire system of governing equations.

  7. Acquiring Multiview C-Arm Images to Assist Cardiac Ablation Procedures

    Directory of Open Access Journals (Sweden)

    Pascal Fallavollita

    2010-01-01

    Full Text Available CARTO XP is an electroanatomical cardiac mapping system that provides 3D color-coded maps of the electrical activity of the heart; however it is expensive and it can only use a single costly magnetic catheter for each patient intervention. Our approach consists of integrating fluoroscopic and electrical data from the RF catheters into the same image so as to better guide RF ablation, shorten the duration of this procedure, increase its efficacy, and decrease hospital cost when compared to CARTO XP. We propose a method that relies on multi-view C-arm fluoroscopy image acquisition for (1 the 3D reconstruction of the anatomical structure of interest, (2 the robust temporal tracking of the tip-electrode of a mapping catheter between the diastolic and systolic phases and (3 the 2D/3D registration of color coded isochronal maps directly on the 2D fluoroscopy image that would help the clinician guide the ablation procedure much more effectively. The method has been tested on canine experimental data.

  8. 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.

  9. The clinical application of DSA and Xper-CT in guiding lung tumor radiofrequency ablation procedure

    International Nuclear Information System (INIS)

    Objective: To discuss the clinical application of DSA and Xper-CT in guiding lung tumor radiofrequency ablation (RFA). Methods: Navigated by DSA and Xper-CT images, RFA was performed in 21 patients with lung tumor. The tumors included peripheral lung cancer (n=3) and lung metastases from hepatocellular carcinoma (n=12) or from colorectal cancer (n=6). The lesions were located at left upper lobe (n=5), at left lower lobe (n=2), at right upper lobe (n=5), at right middle lobe (n=6) and at right lower lobe (n=4). One lesion was situated at the right thoracic wall and one lesion was situated at the left thoracic wall. Results: A total of 24 lesions were detected in the 21 patients. Of the 24 lesions, successful puncturing with single procedure was obtained in 22, with a success rate of 91.67%. Two lesions had the diameter less than one cm, and the treatment was accomplished after two times of puncturing. Conclusion: For the treatment of lung tumors, DSA and Xper-CT-guided radiofrequency ablation is clinically - safe and technically - simple with higher localizing accuracy. Therefore, this technique should be recommended in clinical practice. (authors)

  10. Effective dose analysis of three-dimensional rotational angiography during catheter ablation procedures

    Science.gov (United States)

    Wielandts, J.-Y.; Smans, K.; Ector, J.; De Buck, S.; Heidbüchel, H.; Bosmans, H.

    2010-02-01

    There is increasing use of three-dimensional rotational angiography (3DRA) during cardiac ablation procedures. As compared with 2D angiography, a large series of images are acquired, creating the potential for high radiation doses. The aim of the present study was to quantify patient-specific effective doses. In this study, we developed a computer model to accurately calculate organ doses and the effective dose incurred during 3DRA image acquisition. The computer model simulates the exposure geometry and uses the actual exposure parameters, including the variation in tube voltage and current that is realized through the automatic exposure control (AEC). We performed 3DRA dose calculations in 42 patients referred for ablation on the Siemens Axiom Artis DynaCT system (Erlangen, Germany). Organ doses and effective dose were calculated separately for all projections in the course of the C-arm rotation. The influence of patient body mass index (BMI), dose-area product (DAP), collimation and dose per frame (DPF) rate setting on the calculated doses was also analysed. The effective dose was found to be 5.5 ± 1.4 mSv according to ICRP 60 and 6.6 ± 1.8 mSv according to ICRP 103. Effective dose showed an inversely proportional relationship to BMI, while DAP was nearly BMI independent. No simple conversion coefficient between DAP and effective dose could be derived. DPF reduction did not result in a proportional effective dose decrease. These paradoxical findings were explained by the settings of the AEC and the limitations of the x-ray tube. Collimation reduced the effective dose by more than 20%. Three-dimensional rotational angiography is associated with a definite but acceptable radiation dose that can be calculated for all patients separately. Their BMI is a predictor of the effective dose. The dose reduction achieved with collimation suggests that its use is imperative during the 3DRA procedure.

  11. Effective dose analysis of three-dimensional rotational angiography during catheter ablation procedures

    Energy Technology Data Exchange (ETDEWEB)

    Wielandts, J-Y; Ector, J; De Buck, S; Heidbuechel, H [Department of Electrophysiology-Cardiology, University Hospital Gasthuisberg, 49, Herestraat, 3000-Leuven (Belgium); Smans, K [Belgian Nuclear Research Centre (SCK-CEN), Radiation Protection, Dosimetry and Calibration, Boeretang, 2400-Mol (Belgium); Bosmans, H [Department of Radiology, University Hospital Gasthuisberg, 49, Herestraat, 3000-Leuven (Belgium)], E-mail: jean-yves.wielandts@uz.kuleuven.ac.be

    2010-02-07

    There is increasing use of three-dimensional rotational angiography (3DRA) during cardiac ablation procedures. As compared with 2D angiography, a large series of images are acquired, creating the potential for high radiation doses. The aim of the present study was to quantify patient-specific effective doses. In this study, we developed a computer model to accurately calculate organ doses and the effective dose incurred during 3DRA image acquisition. The computer model simulates the exposure geometry and uses the actual exposure parameters, including the variation in tube voltage and current that is realized through the automatic exposure control (AEC). We performed 3DRA dose calculations in 42 patients referred for ablation on the Siemens Axiom Artis DynaCT system (Erlangen, Germany). Organ doses and effective dose were calculated separately for all projections in the course of the C-arm rotation. The influence of patient body mass index (BMI), dose-area product (DAP), collimation and dose per frame (DPF) rate setting on the calculated doses was also analysed. The effective dose was found to be 5.5 {+-} 1.4 mSv according to ICRP 60 and 6.6 {+-} 1.8 mSv according to ICRP 103. Effective dose showed an inversely proportional relationship to BMI, while DAP was nearly BMI independent. No simple conversion coefficient between DAP and effective dose could be derived. DPF reduction did not result in a proportional effective dose decrease. These paradoxical findings were explained by the settings of the AEC and the limitations of the x-ray tube. Collimation reduced the effective dose by more than 20%. Three-dimensional rotational angiography is associated with a definite but acceptable radiation dose that can be calculated for all patients separately. Their BMI is a predictor of the effective dose. The dose reduction achieved with collimation suggests that its use is imperative during the 3DRA procedure.

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

    OpenAIRE

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

    2014-01-01

    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 1 mg (low) Harmine and 5 mg (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 ...

  13. Laser Ablation Of Atrial Fibrillation: Mid-term Clinical Experience

    Directory of Open Access Journals (Sweden)

    Li Poa, MD

    2009-08-01

    Full Text Available Background: Atrial Fibrillation is known to account for one third of all the strokes caused in the US in the population above the age of 70. Patients treated with the surgical Cox MAZE operation have been shown to have a 150 fold decrease in the incidence of stroke over an 18 year period. However, the original Cox MAZE although extremely successful in treating atrial fibrillation and decreasing the incidence of strokes was not performed widely because of complexity and invasiveness of the procedure. A variety of alternative energy based curative ablation strategies are now available for more minimally invasive therapeutic management of atrial fibrillation (AF. In this communication, we report our clinical experience in AF therapy utilizing laser energy ablation technology. Methods: Fifty two consecutive AF patients underwent concomitant or isolated ablation prior to any coexisting cardiac procedures that included CABG (coronary artery bypass surgery, MV (mitral valve or AV (aortic valve repairs. All patients had an epicardially based ablation pattern with basic lesions being en bloc box type pulmonary vein isolation which included the antral surface of the left atrium, directed ganglionectomies of the the right anterior and inferior ganglions, posteriomedial ablation of the IVC ( inferior vena cava, and a right isthmus ablation. Twenty seven patients had ligation of their left atrial appendage, 14 patients had resection of the ligament of Marshall, and three patients had endocardial placed lesions of a mitral annular connecting type lesion. In order to maintain the patients in normal sinus rhythm (NSR, electrical cardioversion and anti-arrhythmic drugs were employed as required. Results: At a median follow-up of 250 days, 44 of the total 52 patients (84.6% exhibited NSR.. No complications or mortality were reported due to the laser procedure. Conclusion: Laser ablation was successfully and safely used for endocardial and epicardial AF ablation

  14. 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.

  15. Electric Current Solves Mazes

    Science.gov (United States)

    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:…

  16. 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

    BACKGROUND: The objectives of this study were to assess the procedural outcomes of persistent and long-standing persistent atrial fibrillation (PsAF and L-PsAF) ablation guided by remote magnetic navigation (RMN), and to detect factors predicting acute restoration of sinus rhythm (SR) by ablation...... 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.......03). Stepwise regression analysis showed LA volume was the primary parameter affecting SR restoration (P = 0.01). The LA volume of patients without direct SR restoration by ablation was 24% greater than that of patients with SR restoration (P RMN is a safe...

  17. Radiofrequency catheter ablation of atrioventricular nodal reentrant tachycardia guided by magnetic navigation system: a prospective randomized comparison with conventional procedure

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yu-xiao; LU Cai-yi; XUE Qiao; LI Ke; YAN Wei; ZHOU Sheng-hua

    2012-01-01

    Background Atrioventricular nodal reentrant tachycardia (AVNRT) is one of the most common paroxysmal supraventricular tachyarrhythmias.The aim of the study was to prospectively compare the characteristics of radiofrequency catheter ablation of AVNRT guided by a magnetic navigation system with the conventional procedure.Methods Patients with AVNRT diagnosed by electrophysiological tests were randomized into two groups.In the conventional technique group (CMT),a common 4-mm-tip quadrapolar temperature-controlled ablation catheter was used. In the magnetic navigation system guidance group (MNS), a magnetic 4-mm-tip quadrapolar temperature-controlled ablation catheter was used.The following parameters were collected and compared between the two groups: ablation procedure time,patient fluoroscopy time,operator fluoroscopy time,energy delivery numbers,maximal energy per deployment,success rate,complication rate and operative cost.Results Forty patients were enrolled and randomized into CMT and MNS groups.The age,gender,tachycardia history and basic cardiovascular diseases of the two groups were comparable (P >0.05).All procedures were conducted successfully without complications.No tachycardia recurred during the follow-up period of (9.3±2.6) months.In the MNS group,the patient and operator fluoroscopy times ((11.5±4.3) min,(4.2±1.5) min),energy delivery numbers (3.2±0.9),and maximal energy per deployment ((16.9±3.4) W) were shorter or lower than those of the CMT group ((14.3±6.2) min,(13.6±3.5) min,6.3±2.1,(23.7±1.3) W,respectively) (P <0.05).But the operative cost for the MNS group was higher than that of the CMT group (P <0.01 ).Conclusion Magnetic navigation system guided radiofrequency catheter ablation of AVNRT has the advantages of shorter fluoroscopy time and lower energy delivery numbers and maximal energy per deployment compared to the present conventional ablation technique.

  18. Rook Jumping Maze Design Considerations

    Science.gov (United States)

    Neller, Todd W.; Fisher, Adrian; Choga, Munyaradzi T.; Lalvani, Samir M.; McCarty, Kyle D.

    We define the Rook Jumping Maze, provide historical perspective, and describe a generation method for such mazes. When applying stochastic local search algorithms to maze design, most creative effort concerns the definition of an objective function that rates maze quality. We define and discuss several maze features to consider in such a function definition. Finally, we share our preferred design choices, make design process observations, and note the applicability of these techniques to variations of the Rook Jumping Maze.

  19. Paracardioscopic Ex-Maze

    Medline Plus

    Full Text Available ... ablation line somewhere, that's not contiguous. There's a gap that needs to be fixed. Again, you put ... on the pulmonary vein and because there's a gap, electricity is going across the ablation line and ...

  20. Reinforce the study of treatment of atrial fibrillation by catheter ablation

    Institute of Scientific and Technical Information of China (English)

    HUANG Cong-xin

    2005-01-01

    @@ In the past decade, there is a great progress in the treatment of atrial fibrillation (AF) by transcatheter ablation. The catheter-based procedures have developed from Maze-like linear lesion, focal lesion to segmental electrical isolation of pulmonary veins and circumferential ablation under guidance of anatomical mapping, ablation energy developed from radiofrequency to multiple energy such as radiofrequency, ultrasound and cryoablation; and success rate has risen to 90% from around 30% in the past.1 Catheter ablation has been widely accepted as a treatment of AF and tends to substitute pharmacological therapy and become first-line treatment gradually. It must point out that, however, catheter ablation of AF is not perfect and there are many issues desiderating resolution.

  1. Paracardioscopic Ex-Maze

    Medline Plus

    Full Text Available ... However, in the pattern you see on the right, that is an open-chest pattern. That's the ... minimally invasive paracardioscopic Ex-Maze pattern on the right. This pattern is one that's very similar to, ...

  2. Paracardioscopic Ex-Maze

    Medline Plus

    Full Text Available ... That pattern that he described has been the gold standard to treat all types of atrial fibrillation, ... from A Fib and anti-rhythmic medications. The gold standard at six months, the surgical Maze 3 ...

  3. Magnetic Resonance Imaging-Guided High-Intensity Focused Ultrasound Ablation of Uterine Fibroids: Effect of Bowel Interposition on Procedure Feasibility and a Unique Bowel Displacement Technique

    OpenAIRE

    Young-Sun Kim; Hyo Keun Lim; Hyunchul Rhim

    2016-01-01

    Purpose To evaluate the effect of bowel interposition on assessing procedure feasibility, and the usefulness and limiting conditions of bowel displacement techniques in magnetic resonance imaging-guided high-intensity focused ultrasound (MR-HIFU) ablation of uterine fibroids. Materials and Methods Institutional review board approved this study. A total of 375 screening MR exams and 206 MR-HIFU ablations for symptomatic uterine fibroids performed between August 2010 and March 2015 were retrosp...

  4. 2D/3D registration using only single-view fluoroscopy to guide cardiac ablation procedures: a feasibility study

    Science.gov (United States)

    Fallavollita, Pascal

    2010-02-01

    The CARTO XP is an electroanatomical cardiac mapping system that provides 3D color-coded maps of the electrical activity of the heart, however it is expensive and it can only use a single costly magnetic catheter for each patient intervention. Aim: To develop an affordable fluoroscopic navigation system that could shorten the duration of RF ablation procedures and increase its efficacy. Methodology: A 4-step filtering technique was implemented in order to project the tip electrode of an ablation catheter visible in single-view C-arm images in order to calculate its width. The width is directly proportional to the depth of the catheter. Results: For phantom experimentation, when displacing a 7- French catheter at 1cm intervals away from an X-ray source, the recovered depth using a single image was 2.05 +/- 1.47 mm, whereas depth errors improved to 1.55 +/- 1.30 mm when using an 8-French catheter. In clinic experimentation, twenty posterior and left lateral images of a catheter inside the left ventricle of a mongrel dog were acquired. The standard error of estimate for the recovered depth of the tip-electrode of the mapping catheter was 13.1 mm and 10.1 mm respectively for the posterior and lateral views. Conclusions: A filtering implementation using single-view C-arm images showed that it was possible to recover depth in phantom study and proved adequate in clinical experimentation based on isochronal map fusion results.

  5. Cone-Beam Computed Tomography (CBCT) Versus CT in Lung Ablation Procedure: Which is Faster?

    Energy Technology Data Exchange (ETDEWEB)

    Cazzato, Roberto Luigi, E-mail: r.cazzato@unicampus.it; Battistuzzi, Jean-Benoit, E-mail: j.battistuzzi@bordeaux.unicancer.fr; Catena, Vittorio, E-mail: vittoriocatena@gmail.com [Institut Bergonié, Department of Radiology (France); Grasso, Rosario Francesco, E-mail: r.grasso@unicampus.it; Zobel, Bruno Beomonte, E-mail: b.zobel@unicampus.it [Università Campus Bio-Medico di Roma, Department of Radiology and Diagnostic Imaging (Italy); Schena, Emiliano, E-mail: e.schena@unicampus.it [Università Campus Bio-Medico di Roma, Unit of Measurements and Biomedical Instrumentations, Biomedical Engineering Laboratory (Italy); Buy, Xavier, E-mail: x.buy@bordeaux.unicancer.fr; Palussiere, Jean, E-mail: j.palussiere@bordeaux.unicancer.fr [Institut Bergonié, Department of Radiology (France)

    2015-10-15

    AimTo compare cone-beam CT (CBCT) versus computed tomography (CT) guidance in terms of time needed to target and place the radiofrequency ablation (RFA) electrode on lung tumours.Materials and MethodsPatients at our institution who received CBCT- or CT-guided RFA for primary or metastatic lung tumours were retrospectively included. Time required to target and place the RFA electrode within the lesion was registered and compared across the two groups. Lesions were stratified into three groups according to their size (<10, 10–20, >20 mm). Occurrences of electrode repositioning, repositioning time, RFA complications, and local recurrence after RFA were also reported.ResultsForty tumours (22 under CT, 18 under CBCT guidance) were treated in 27 patients (19 male, 8 female, median age 67.25 ± 9.13 years). Thirty RFA sessions (16 under CBCT and 14 under CT guidance) were performed. Multivariable linear regression analysis showed that CBCT was faster than CT to target and place the electrode within the tumour independently from its size (β = −9.45, t = −3.09, p = 0.004). Electrode repositioning was required in 10/22 (45.4 %) tumours under CT guidance and 5/18 (27.8 %) tumours under CBCT guidance. Pneumothoraces occurred in 6/14 (42.8 %) sessions under CT guidance and in 6/16 (37.5 %) sessions under CBCT guidance. Two recurrences were noted for tumours receiving CBCT-guided RFA (2/17, 11.7 %) and three after CT-guided RFA (3/19, 15.8 %).ConclusionCBCT with live 3D needle guidance is a useful technique for percutaneous lung ablation. Despite lesion size, CBCT allows faster lung RFA than CT.

  6. Paracardioscopic Ex-Maze

    Medline Plus

    Full Text Available ... see the previous ablation line just at that black arrow. So now I can see my previous ... of the diaphragmatic defect. This is the same hole we created to put the paracardioscopic cannula in. ...

  7. Paracardioscopic Ex-Maze

    Medline Plus

    Full Text Available ... pulmonary veins, be happy, be satisfied that the orientation of the device is into the heart and ... camera, through the chest, that it's in appropriate orientation and it's ablation the left anterior pulmonary veins. ...

  8. Paracardioscopic Ex-Maze

    Medline Plus

    Full Text Available ... slide, that demonstrates how the VisiTrax ablation device works. It's a suction device. It actually sucks up ... and you can see now how we can work with the assistance of a technician, a nurse, ...

  9. Paracardioscopic Ex-Maze

    Medline Plus

    Full Text Available ... you can see the monitor that monitors the energy that we're delivering to create the ablation ... with the heart. Because we do that, the energy can be directed into the heart and create ...

  10. Paracardioscopic Ex-Maze

    Medline Plus

    Full Text Available ... appropriate orientation and it's ablation the left anterior pulmonary veins. Once that line is completed, we go back to the right chest and you can see now how we can work with the assistance of a technician, a nurse, ...

  11. Limited posterior left atrial linear radiofrequency ablation for patients with chronic atrial fibrillation undergoing rheumatic valvular heart surgery

    Institute of Scientific and Technical Information of China (English)

    王均志; 杜日映; 丁会霞; 柏本健; 王刚; 崔国方; 钟志欢

    2004-01-01

    @@ Since 1996, we have begun to successfully treat atrial fibrillation (AF) with the maze procedure, replacing surgical incisions with radiofrequency (RF) ablation.1,2 Recent data show that the posterior wall of the left atrium seems to be a critical area for the occurrence and the maintenance of AF in patients with valvular heart disease. The objective of this study was to evaluate whether limited surgical RF ablation of the posterior region of the left atrium is safe and effective in curing chronic AF in patients also suffering from valvular heart disease.

  12. Paracardioscopic Ex-Maze

    Medline Plus

    Full Text Available ... enhanced procedures and we created a lot of new procedures. One of those procedures was a totally ... fatigued, almost all the time, to an enormous new sense of energy. Certainly I'd say anyone ...

  13. Quantitative modeling of the accuracy in registering preoperative patient-specific anatomic models into left atrial cardiac ablation procedures

    Energy Technology Data Exchange (ETDEWEB)

    Rettmann, Maryam E., E-mail: rettmann.maryam@mayo.edu; Holmes, David R.; Camp, Jon J.; Cameron, Bruce M.; Robb, Richard A. [Biomedical Imaging Resource, Mayo Clinic College of Medicine, Rochester, Minnesota 55905 (United States); Kwartowitz, David M. [Department of Bioengineering, Clemson University, Clemson, South Carolina 29634 (United States); Gunawan, Mia [Department of Biochemistry and Molecular and Cellular Biology, Georgetown University, Washington D.C. 20057 (United States); Johnson, Susan B.; Packer, Douglas L. [Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota 55905 (United States); Dalegrave, Charles [Clinical Cardiac Electrophysiology, Cardiology Division Hospital Sao Paulo, Federal University of Sao Paulo, 04024-002 Brazil (Brazil); Kolasa, Mark W. [David Grant Medical Center, Fairfield, California 94535 (United States)

    2014-02-15

    Purpose: In cardiac ablation therapy, accurate anatomic guidance is necessary to create effective tissue lesions for elimination of left atrial fibrillation. While fluoroscopy, ultrasound, and electroanatomic maps are important guidance tools, they lack information regarding detailed patient anatomy which can be obtained from high resolution imaging techniques. For this reason, there has been significant effort in incorporating detailed, patient-specific models generated from preoperative imaging datasets into the procedure. Both clinical and animal studies have investigated registration and targeting accuracy when using preoperative models; however, the effect of various error sources on registration accuracy has not been quantitatively evaluated. Methods: Data from phantom, canine, and patient studies are used to model and evaluate registration accuracy. In the phantom studies, data are collected using a magnetically tracked catheter on a static phantom model. Monte Carlo simulation studies were run to evaluate both baseline errors as well as the effect of different sources of error that would be present in a dynamicin vivo setting. Error is simulated by varying the variance parameters on the landmark fiducial, physical target, and surface point locations in the phantom simulation studies. In vivo validation studies were undertaken in six canines in which metal clips were placed in the left atrium to serve as ground truth points. A small clinical evaluation was completed in three patients. Landmark-based and combined landmark and surface-based registration algorithms were evaluated in all studies. In the phantom and canine studies, both target registration error and point-to-surface error are used to assess accuracy. In the patient studies, no ground truth is available and registration accuracy is quantified using point-to-surface error only. Results: The phantom simulation studies demonstrated that combined landmark and surface-based registration improved

  14. Quantitative modeling of the accuracy in registering preoperative patient-specific anatomic models into left atrial cardiac ablation procedures

    International Nuclear Information System (INIS)

    Purpose: In cardiac ablation therapy, accurate anatomic guidance is necessary to create effective tissue lesions for elimination of left atrial fibrillation. While fluoroscopy, ultrasound, and electroanatomic maps are important guidance tools, they lack information regarding detailed patient anatomy which can be obtained from high resolution imaging techniques. For this reason, there has been significant effort in incorporating detailed, patient-specific models generated from preoperative imaging datasets into the procedure. Both clinical and animal studies have investigated registration and targeting accuracy when using preoperative models; however, the effect of various error sources on registration accuracy has not been quantitatively evaluated. Methods: Data from phantom, canine, and patient studies are used to model and evaluate registration accuracy. In the phantom studies, data are collected using a magnetically tracked catheter on a static phantom model. Monte Carlo simulation studies were run to evaluate both baseline errors as well as the effect of different sources of error that would be present in a dynamicin vivo setting. Error is simulated by varying the variance parameters on the landmark fiducial, physical target, and surface point locations in the phantom simulation studies. In vivo validation studies were undertaken in six canines in which metal clips were placed in the left atrium to serve as ground truth points. A small clinical evaluation was completed in three patients. Landmark-based and combined landmark and surface-based registration algorithms were evaluated in all studies. In the phantom and canine studies, both target registration error and point-to-surface error are used to assess accuracy. In the patient studies, no ground truth is available and registration accuracy is quantified using point-to-surface error only. Results: The phantom simulation studies demonstrated that combined landmark and surface-based registration improved

  15. Impairment of reward-related learning by cholinergic cell ablation in the striatum.

    Science.gov (United States)

    Kitabatake, Yasuji; Hikida, Takatoshi; Watanabe, Dai; Pastan, Ira; Nakanishi, Shigetada

    2003-06-24

    The striatum in the basal ganglia-thalamocortical circuitry is a key neural substrate that is implicated in motor balance and procedural learning. The projection neurons in the striatum are dynamically modulated by nigrostriatal dopaminergic input and intrastriatal cholinergic input. The role of intrastriatal acetylcholine (ACh) in learning behaviors, however, remains to be fully clarified. In this investigation, we examine the involvement of intrastriatal ACh in different categories of learning by selectively ablating the striatal cholinergic neurons with use of immunotoxin-mediated cell targeting. We show that selective ablation of cholinergic neurons in the striatum impairs procedural learning in the tone-cued T-maze memory task. Spatial delayed alternation in the T-maze learning test is also impaired by cholinergic cell elimination. In contrast, the deficit in striatal ACh transmission has no effect on motor learning in the rota-rod test or spatial learning in the Morris water-maze test or on contextual- and tone-cued conditioning fear responses. We also report that cholinergic cell elimination adaptively up-regulates nicotinic ACh receptors not only within the striatum but also in the cerebral cortex and substantia nigra. The present investigation indicates that cholinergic modulation in the local striatal circuit plays a pivotal role in regulation of neural circuitry involving reward-related procedural learning and working memory. PMID:12802017

  16. The procedure outcome of laparoscopic resection for ‘small’ hepatocellular carcinoma is comparable to vlaparoscopic radiofrequency ablation

    Science.gov (United States)

    Casaccia, Marco; Santori, Gregorio; Bottino, Giuliano; Diviacco, Pietro; Negri, Antonella De; Moraglia, Eva; Adorno, Enzo

    2015-01-01

    BACKGROUND: The aim of this study was to compare the effectiveness of laparoscopic liver resection (LLR) and laparoscopic radiofrequency ablation (LRFA) in the treatment of small nodular hepatocellular carcinoma (HCC). PATIENTS AND METHODS: We enrolled 50 cirrhotic patients with similar baseline characteristics that underwent LLR (n = 26) or LRFA (n = 24), in both cases with intraoperative ultrasonography. Operative and peri-operative data were retrospectively evaluated. RESULTS: LLR included anatomic resection in eight cases and non-anatomic resection in 18. In LRFA patients, a thermoablation of 62 nodules was achieved. Between LLR and LRFA groups, a significant difference was found both for median diameters of treated HCC nodules (30 vs. 17.1 mm; P < 0.001) and the number of treated nodules/patient (1.29 ± 0.62 vs. 2.65 ± 1.55; P < 0.001). A conversion to laparotomy occurred in two LLR patient (7.7%) for bleeding. No deaths occurred in both groups. Morbidity rates were 26.9% in the LLR group versus 16.6% in the LRFA group (P = 0.501). Hospital stay in the LLR and LRFA group was 8.30 ± 6.52 and 6.52 ± 2.69 days, respectively (P = 0.022). The surgical margin was free of tumour cells in all LLR patients, with a margin <5 mm in only one case. In the LRFA group, a complete response was achieved in 90.3% of thermoablated HCC nodules at the 1-month post-treatment computed tomography evaluation. CONCLUSIONS: LLR for small peripheral HCC in patients with chronic liver disease represents a valid alternative to LRFA in terms of patient toleration, surgical outcome of the procedure, and short-term morbidity. PMID:26622111

  17. Paracardioscopic Ex-Maze

    Medline Plus

    Full Text Available ... FirstHealth Moore Regional Hospital in Pinehurst, North Carolina. I'm Dr. Andy Kiser, Medical Director of the ... chest procedure to a totally endoscopic procedure and I've been involved in the development of a ...

  18. Paracardioscopic Ex-Maze

    Medline Plus

    Full Text Available ... heart. Unique to this procedure is actually an access to the heart, through the abdomen. An incision ... very small defect in the diaphragm to gain access to the heart. Here, these instruments that we ...

  19. Paracardioscopic Ex-Maze

    Medline Plus

    Full Text Available ... to you, Mr. Woods. Coming from Europe, our system is a little bit different. So, what would ... is no, they don't. Actually, also in robotic surgery and in other totally endoscopic procedures we ...

  20. Paracardioscopic Ex-Maze

    Medline Plus

    Full Text Available ... atrial fibrillation of almost 80 percent. Although our numbers are small, the initial six month data for ... to make the procedure less invasive, decrease the number of incisions, improve the device to make it ...

  1. Paracardioscopic Ex-Maze

    Medline Plus

    Full Text Available ... 45:48 JON WOODS: A little discomfort. I sleep on my right side. A little discomfort for ... t get tired and we don't lose quality in performing those procedures. One question coming from ...

  2. Paracardioscopic Ex-Maze

    Medline Plus

    Full Text Available ... off medication. It is getting better quality of life, by not having to take so many medications, ... Mr. Woods would agree, minimally invasive into their life. Because we can do this procedure with the ...

  3. Paracardioscopic Ex-Maze

    Medline Plus

    Full Text Available ... and some of the slides, some of the data. These are the results of the first 39 ... our numbers are small, the initial six month data for the minimally invasive procedure closely reflects that ...

  4. Paracardioscopic Ex-Maze

    Medline Plus

    Full Text Available ... I can see the heart, but the unique advantage to this is the patient is asleep, but ... problem at that time, which again is an advantage to this procedure because the patient's laying flat ...

  5. Implementation of Endovenous Laser Ablation for Varicose Veins in a Large Community Hospital : The First 400 Procedures

    NARCIS (Netherlands)

    van den Bremer, J.; Joosten, P. Ph. A. Hedeman; Hamming, J. F.; Moll, F. L.

    2009-01-01

    Endovenous Laser ablation (ELA) has become a standard treatment of the incompetent great saphenous vein (GSV). Our prospective audit examines the implementation of this new method in a large community hospital with special attention to obstacles, technical results, pain scores, failures and our lear

  6. Percutaneous radiofrequency ablation: relationship between different probe types and procedure time on length and extent of osteonecrosis in dog long bones

    Energy Technology Data Exchange (ETDEWEB)

    Martel, J.; Bueno, A. [Fundacion Hospital Alcorcon, Departamento de Diagnostico por Imagen, Alcorcon, Madrid (Spain); Dominguez, M.P. [Fundacion Hospital Alcorcon, Departamento de Patologia, Alcorcon, Madrid (Spain); Llorens, P.; Quiros, J.; Delgado, C. [Universidad Complutense, Facultad de Veterinaria, Madrid (Spain)

    2008-02-15

    We have been using radiofrequency ablation for the percutaneous treatment of osteoid osteoma since 2001. Frequently, lesions are located near the joint surface, involve the vertebral body or are close to major nerves. We seek to determine whether radiofrequency ablation (RFA) can be used safely in these cases. A total of 65 lesions were induced in 4 dogs. Each dog underwent RFA on the diaphysis of long bones, as well as femoral and humeral heads. Four different sessions were carried out by using 1- and 2-cm probes with or without a cool-tip system and by varying the timing of the procedure. Plain film, CT, and MRI were obtained. All bone samples were examined histologically. The dogs' activity after the procedure was normal. No pathologic fractures occurred despite unrestricted activity of the animals. Cortical bone was always respected; therefore, articular cartilage has not been damaged. Radiological findings were characteristic. There were no significant differences in lesion size, probe type, and the duration of the procedure. The mean lesion diameter perpendicular to the electrode was 18.5 mm. Our study confirms the insulative effect of cortical bone. RFA can be safely performed close to the joint surface without damaging the cartilage. (orig.)

  7. Paracardioscopic Ex-Maze

    Medline Plus

    Full Text Available ... Canada.” Another question coming from Michigan is “Will insurance pay?” 00:51:03 ANDY C. KISER, MD: ... diagnostic related groups. This is the way that Medicare pays and defines payment for procedures like this. ...

  8. Paracardioscopic Ex-Maze

    Medline Plus

    Full Text Available ... very important in this procedure. Over my left shoulder, you can see two cameras – the two cameras ... the incisions to help control any post-operative pain. 00:34:43 GERHARD WIMMER-GREINECKER, MD, PhD: ...

  9. Magnetic Resonance Imaging-Guided High-Intensity Focused Ultrasound Ablation of Uterine Fibroids: Effect of Bowel Interposition on Procedure Feasibility and a Unique Bowel Displacement Technique.

    Directory of Open Access Journals (Sweden)

    Young-Sun Kim

    Full Text Available To evaluate the effect of bowel interposition on assessing procedure feasibility, and the usefulness and limiting conditions of bowel displacement techniques in magnetic resonance imaging-guided high-intensity focused ultrasound (MR-HIFU ablation of uterine fibroids.Institutional review board approved this study. A total of 375 screening MR exams and 206 MR-HIFU ablations for symptomatic uterine fibroids performed between August 2010 and March 2015 were retrospectively analyzed. The effect of bowel interposition on procedure feasibility was assessed by comparing pass rates in periods before and after adopting a unique bowel displacement technique (bladder filling, rectal filling and subsequent bladder emptying; BRB maneuver. Risk factors for BRB failure were evaluated using logistic regression analysis.Overall pass rates of pre- and post-BRB periods were 59.0% (98/166 and 71.7% (150/209, and in bowel-interposed cases they were 14.6% (7/48 and 76.4% (55/72, respectively. BRB maneuver was technically successful in 81.7% (49/60. Through-the-bladder sonication was effective in eight of eleven BRB failure cases, thus MR-HIFU could be initiated in 95.0% (57/60. A small uterus on treatment day was the only significant risk factor for BRB failure (B = 0.111, P = 0.017.The BRB maneuver greatly reduces the fraction of patients deemed ineligible for MR-HIFU ablation of uterine fibroids due to interposed bowels, although care is needed when the uterus is small.

  10. Magnetic resonance angiography virtual endoscopy in the assessment of pulmonary veins before radiofrequency ablation procedures for atrial fibrillation

    International Nuclear Information System (INIS)

    Magnetic resonance angiography (MRA) is a safe and non-invasive imaging method that can readily depict the pulmonary veins (PV), whose imaging has acquired momentum with the advent of new techniques for radiofrequency ablation of atrial fibrillation (AF). We evaluated whether virtual endoscopy from 3D MRA images (MRA-VE) is feasible in studying the morphology of PV. Fifty patients with AF underwent pre-ablative MRA (1.5 T). Images were acquired with axial T-2 weighted and 3D-SPGR sequences after intravenous administration of Gd-DTPA and automatic triggering. Postprocessing was performed by an experienced radiologist with maximum intensity projection (MIP) and virtual endoscopy software (Navigator, GEMS). The venoatrial junction was visualized with MRA-VE in 49 of 50 patients (98.0%). Twenty-seven patients (55.1%) had two ostia on both sides, 13 patients (26.5%) had two ostia on the right and a single common ostium on the left, 5 patients (10.2%) had accessory PV and 4 patients (8.2%) had both an accessory right PV and a single common ostium on the left. Flythrough navigation showed the number and spatial disposition of second-order PV branches in 48 out of 49 patients (98.0%). MRA-VE is an excellent tool for at-a-glance visualization of ostia morphology, navigation of second-generation PV branches and easy endoluminal assessment of left atrial structures in pre-ablative imaging. (orig.)

  11. Magnetic resonance angiography virtual endoscopy in the assessment of pulmonary veins before radiofrequency ablation procedures for atrial fibrillation

    Energy Technology Data Exchange (ETDEWEB)

    Cirillo, S.; Tosetti, Irene; Giuseppe, M.De; Longo, M.; Regge, D. [Institute for Cancer Research and Treatment (IRCC), Unit of Radiology, Candiolo (Torino) (Italy); Bonamini, R. [University of Torino, Department of Cardiology, Torino (Italy); Gaita, F.; Bianchi, F.; Vivalda, L. [Ospedale Mauriziano Umberto I, Department of Cardiology, Torino (Italy)

    2004-11-01

    Magnetic resonance angiography (MRA) is a safe and non-invasive imaging method that can readily depict the pulmonary veins (PV), whose imaging has acquired momentum with the advent of new techniques for radiofrequency ablation of atrial fibrillation (AF). We evaluated whether virtual endoscopy from 3D MRA images (MRA-VE) is feasible in studying the morphology of PV. Fifty patients with AF underwent pre-ablative MRA (1.5 T). Images were acquired with axial T-2 weighted and 3D-SPGR sequences after intravenous administration of Gd-DTPA and automatic triggering. Postprocessing was performed by an experienced radiologist with maximum intensity projection (MIP) and virtual endoscopy software (Navigator, GEMS). The venoatrial junction was visualized with MRA-VE in 49 of 50 patients (98.0%). Twenty-seven patients (55.1%) had two ostia on both sides, 13 patients (26.5%) had two ostia on the right and a single common ostium on the left, 5 patients (10.2%) had accessory PV and 4 patients (8.2%) had both an accessory right PV and a single common ostium on the left. Flythrough navigation showed the number and spatial disposition of second-order PV branches in 48 out of 49 patients (98.0%). MRA-VE is an excellent tool for at-a-glance visualization of ostia morphology, navigation of second-generation PV branches and easy endoluminal assessment of left atrial structures in pre-ablative imaging. (orig.)

  12. Second Language Learning with the Story Maze Task: Examining the Training Effect of Weaving through Stories

    Science.gov (United States)

    Enkin, Elizabeth

    2016-01-01

    The maze task is a psycholinguistic experimental procedure that measures real-time incremental sentence processing. The task has recently been tested as a language learning tool with promising results. Therefore, the present study examines the merits of a contextualized version of this task: the story maze. The findings are consistent with…

  13. 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

  14. 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.

  15. Sacro-Iliac Joint Sensory Block and Radiofrequency Ablation: Assessment of Bony Landmarks Relevant for Image-Guided Procedures

    Science.gov (United States)

    Roberts, Shannon L.; Burnham, Robert S.; Loh, Eldon; Agur, Anne M.

    2016-01-01

    Image-guided sensory block and radiofrequency ablation of the nerves innervating the sacro-iliac joint require readily identifiable bony landmarks for accurate needle/electrode placement. Understanding the relative locations of the transverse sacral tubercles along the lateral sacral crest is important for ultrasound guidance, as they demarcate the position of the posterior sacral network (S1–S3 ± L5/S4) innervating the posterior sacro-iliac joint. No studies were found that investigated the spatial relationships of these bony landmarks. The purpose of this study was to visualize and quantify the interrelationships of the transverse sacral tubercles and posterior sacral foramina to inform image-guided block and radiofrequency ablation of the sacro-iliac joint. The posterior and lateral surfaces of 30 dry sacra (15 M/15 F) were digitized and modeled in 3D and the distances between bony landmarks quantified. The relationships of bony landmarks (S1–S4) were not uniform. The mean intertubercular and interforaminal distances decreased from S1 to S4, whereas the distance from the lateral margin of the posterior sacral foramina to the transverse sacral tubercles increased from S1 to S3. The mean intertubercular distance from S1 to S3 was significantly (p < 0.05) larger in males. The interrelationships of the sacral bony landmarks should be taken into consideration when estimating the site and length of an image-guided strip lesion targeting the posterior sacral network. PMID:27747222

  16. Repeat procedure using radiofrequency energy for recurrence of atrial fibrillation after initial cryoballoon ablation: a 2-year follow-up

    NARCIS (Netherlands)

    Conte, G.; Chierchia, G.B.; Sieira, J.; Levinstein, M.; Casado-Arroyo, R.; Asmundis, C. de; Sarkozy, A.; Rodriguez-Manero, M.; Giovanni, G.; Baltogiannis, G.; Wauters, K.; Brugada, P.

    2013-01-01

    AIMS: The ideal energy source needed to perform 're-isolation' of the pulmonary veins (PVs) during a repeat procedure for recurrence of paroxysmal atrial fibrillation (AF) has not been established yet. In this study we analysed the outcome of repeat procedure using radiofrequency (RF) energy after i

  17. Is radiation-induced ovarian ablation in breast cancer an obsolete procedure? Results of a meta-analysis

    Directory of Open Access Journals (Sweden)

    Al Asiri M

    2016-05-01

    Full Text Available Mushabbab Al Asiri,1,* Mutahir A Tunio,1,* Reham Abdulmoniem,2,*1Radiation Oncology, Comprehensive Cancer Center, King Fahad Medical City, Riyadh, Saudi Arabia; 2Radiation Oncology, National Cancer Institute, Cairo, Egypt *These authors contributed equally to this work Background: A meta-analysis was conducted to assess the impact of radiation-induced ovarian ablation (RT-OA on amenorrhea cessation rates, progression-free survival, and overall survival in pre/perimenopausal women with breast cancer. Materials and methods: The Medline, CANCERLIT, and Cochrane Library databases and search engines were searched to identify randomized controlled studies comparing RT-OA with control for early or metastatic breast cancer. Further, radiotherapy doses, techniques, and associated side effects were evaluated. Results: Six controlled trials with a total patient population of 3,317 were identified. Pooled results from these trials showed significant amenorrhea rates (P<0.00001 and increase in progression-free survival in patients treated with RT-OA (P<0.00001. However, there was no difference in overall survival (P=0.37. The majority of patients were treated with larger field sizes with parallel-opposed anteroposterior and posteroanterior pelvic fields. RT-OA was generally well tolerated. Radiotherapy doses of 1,500 cGy in five fractions, 1,500 cGy in four fractions, 1,600 cGy in four fractions, and 2,000 cGy in ten fractions were associated with excellent amenorrhea rates. The resultant funnel plot showed no publication bias (Egger test P=0.16. Conclusion: RT-OA is cost-effective and can safely be used in pre/perimenopausal women with metastatic breast cancer, or if luteinizing hormone-releasing hormone analogs are contraindicated, or in patients in whom fertility preservation is not an issue. Radiation dose of 1,500 cGy in five fractions, 1,500 cGy in four fractions, 1,600 cGy in four fractions, and 2,000 cGy in ten fractions showed more efficacies

  18. Bone and Soft Tissue Ablation

    OpenAIRE

    Foster, Ryan C.B.; Joseph M Stavas

    2014-01-01

    Bone and soft tissue tumor ablation has reached widespread acceptance in the locoregional treatment of various benign and malignant musculoskeletal (MSK) lesions. Many principles of ablation learned elsewhere in the body are easily adapted to the MSK system, particularly the various technical aspects of probe/antenna design, tumoricidal effects, selection of image guidance, and methods to reduce complications. Despite the common use of thermal and chemical ablation procedures in bone and soft...

  19. Is radiation-induced ovarian ablation in breast cancer an obsolete procedure? Results of a meta-analysis

    Science.gov (United States)

    Asiri, Mushabbab Al; Tunio, Mutahir A; Abdulmoniem, Reham

    2016-01-01

    Background A meta-analysis was conducted to assess the impact of radiation-induced ovarian ablation (RT-OA) on amenorrhea cessation rates, progression-free survival, and overall survival in pre/perimenopausal women with breast cancer. Materials and methods The Medline, CANCERLIT, and Cochrane Library databases and search engines were searched to identify randomized controlled studies comparing RT-OA with control for early or metastatic breast cancer. Further, radiotherapy doses, techniques, and associated side effects were evaluated. Results Six controlled trials with a total patient population of 3,317 were identified. Pooled results from these trials showed significant amenorrhea rates (Pwomen with metastatic breast cancer, or if luteinizing hormone-releasing hormone analogs are contraindicated, or in patients in whom fertility preservation is not an issue. Radiation dose of 1,500 cGy in five fractions, 1,500 cGy in four fractions, 1,600 cGy in four fractions, and 2,000 cGy in ten fractions showed more efficacies. However, further studies incorporating three-dimensional conformal radiotherapy and intensity-modulated radiotherapy are warranted. PMID:27307764

  20. Endogenous anxiety and stress responses in water maze and Barnes maze spatial memory tasks

    OpenAIRE

    Harrison, F. E.; Hosseini, A.H.; McDonald, M.P.

    2008-01-01

    The effects of abnormally high or low stress on learning are well established. The Barnes maze and Morris water maze are two commonly-used tests of spatial memory, of which the water maze is considered more stressful; however, until now this has not been demonstrated empirically. In the present study, mice matched for performance on commonly-used anxiety tasks were trained on either the Barnes maze or water maze or received no cognitive testing. Water-maze training induced greater increases i...

  1. Analytical procedure for characterization of medieval wall-paintings by X-ray fluorescence spectrometry, laser ablation inductively coupled plasma mass spectrometry and Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Syta, Olga; Rozum, Karol; Choińska, Marta [Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw (Poland); Zielińska, Dobrochna [Institute of Archaeology, University of Warsaw, Krakowskie Przedmieście 26/28, 00-927 Warsaw (Poland); Żukowska, Grażyna Zofia [Chemical Faculty, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw (Poland); Kijowska, Agnieszka [National Museum in Warsaw, Aleje Jerozolimskie 3, 00-495 Warsaw (Poland); Wagner, Barbara, E-mail: barbog@chem.uw.edu.pl [Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw (Poland)

    2014-11-01

    Analytical procedure for the comprehensive chemical characterization of samples from medieval Nubian wall-paintings by means of portable X-ray fluorescence (pXRF), laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) and Raman spectroscopy (RS) was proposed in this work. The procedure was used for elemental and molecular investigations of samples from archeological excavations in Nubia (modern southern Egypt and northern Sudan). Numerous remains of churches with painted decorations dated back to the 7th–14th century were excavated in the region of medieval kingdoms of Nubia but many aspects of this art and its technology are still unknown. Samples from the selected archeological sites (Faras, Old Dongola and Banganarti) were analyzed in the form of transfers (n = 26), small fragments collected during the excavations (n = 35) and cross sections (n = 15). XRF was used to collect data about elemental composition, LA-ICPMS allowed mapping of selected elements, while RS was used to get the molecular information about the samples. The preliminary results indicated the usefulness of the proposed analytical procedure for distinguishing the substances, from both the surface and sub-surface domains of the wall-paintings. The possibility to identify raw materials from the wall-paintings will be used in the further systematic, archeometric studies devoted to the detailed comparison of various historic Nubian centers. - Highlights: • The analytical procedure for examination of unique wall paintings was proposed. • Identification of pigments and supporting layers of wall-paintings was obtained. • Heterogeneous samples were mapped with the use of LA-ICPMS. • Anatase in the sub-surface regions of samples was detected by Raman spectroscopy.

  2. Analytical procedure for characterization of medieval wall-paintings by X-ray fluorescence spectrometry, laser ablation inductively coupled plasma mass spectrometry and Raman spectroscopy

    International Nuclear Information System (INIS)

    Analytical procedure for the comprehensive chemical characterization of samples from medieval Nubian wall-paintings by means of portable X-ray fluorescence (pXRF), laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) and Raman spectroscopy (RS) was proposed in this work. The procedure was used for elemental and molecular investigations of samples from archeological excavations in Nubia (modern southern Egypt and northern Sudan). Numerous remains of churches with painted decorations dated back to the 7th–14th century were excavated in the region of medieval kingdoms of Nubia but many aspects of this art and its technology are still unknown. Samples from the selected archeological sites (Faras, Old Dongola and Banganarti) were analyzed in the form of transfers (n = 26), small fragments collected during the excavations (n = 35) and cross sections (n = 15). XRF was used to collect data about elemental composition, LA-ICPMS allowed mapping of selected elements, while RS was used to get the molecular information about the samples. The preliminary results indicated the usefulness of the proposed analytical procedure for distinguishing the substances, from both the surface and sub-surface domains of the wall-paintings. The possibility to identify raw materials from the wall-paintings will be used in the further systematic, archeometric studies devoted to the detailed comparison of various historic Nubian centers. - Highlights: • The analytical procedure for examination of unique wall paintings was proposed. • Identification of pigments and supporting layers of wall-paintings was obtained. • Heterogeneous samples were mapped with the use of LA-ICPMS. • Anatase in the sub-surface regions of samples was detected by Raman spectroscopy

  3. Navigating mazes in a virtual environment

    Science.gov (United States)

    Browse, Roger A.; Skillicorn, David B.; Middleman, Darren

    2003-06-01

    In this research we are concerned with computer interfaces with which subjects navigate through maze simulations which are essentially buildings, with corridors and intersections, such as frequently encountered in computer games and simulations. We wish to determine if virtual reality interfaces introduce a performance enhancement that might be expected for display configurations which mimic natural perceptual experiences. We have experimented primarily with two display conditions for presentation of and navigation through the mazes. Subjects either view the maze on a desktop computer monitor, turning and moving within the maze with the mouse in a way that is similar to the configurations used in most first-person role playing computer games, or they viewed the maze from a standing position with a head-mounted display, being free to direct the view of the maze through body and head movements, and using the depression of a mouse button to effect movement in the direction that they were facing. Head-tracking was required for this latter condition. As expected there are striking individual differences in subjects" abilities to learn to traverse the mazes. Across a variety of maze configuration parameters which significantly do influence performance, the results indicate that the virtual reality enhancements have no effect subjects' ability to learn the mazes, either as route knowledge or as cognitive maps.

  4. Sex Differences in a Human Analogue of the Radial Arm Maze: The ''17-Box Maze Test''

    Science.gov (United States)

    Rahman, Q.; Abrahams, S.; Jussab, F.

    2005-01-01

    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 Abrahams, Pickering, Polkey, and Morris (1997) called the 17-Box Maze Test herein. The task encourages allocentric spatial processing, dissociates object from spatial memory, and…

  5. Rotary pin-in-maze discriminator

    Science.gov (United States)

    Benavides, Gilbert L.

    1997-01-01

    A discriminator apparatus and method that discriminates between a unique signal and any other (incorrect) signal. The unique signal is a sequence of events; each event can assume one of two possible event states. Given the unique signal, a maze wheel is allowed to rotate fully in one direction. Given an incorrect signal, both the maze wheel and a pin wheel lock in position.

  6. 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.

  7. [Glass maze in women's leadership].

    Science.gov (United States)

    Barberá Heredia, Ester; Ramos López, Amparo; Candela Agulló, Carlos

    2011-04-01

    Psychological gender discrimination explanations have changed over the past thirty years, becoming more complex in order to obtain a better understanding of the social reality. At the present moment, one of the most interesting research areas is the one referring to the 'glass maze' phenomenon in women's management careers. The main purpose of this work is to reveal the theoretical evolution in an attempt to explain the leadership study from a gender perspective. The consecutive hypotheses, starting with the labour sexual division idea, are becoming more interactive in order to understand the current labour-social situation. Social psychology has underlined the role of beliefs, observed via gender stereotyped roles, prejudiced attitudes against women, sexist and neo-sexist ideology, or masculine, feminine and androgynous identity development. New psychological interpretations insist on the variability of the gender concept, where gender is sometimes observed through men and women's behaviours, and other times through those behaviour expectations. But gender is mainly observed though the power relations between men and women during social interactions in labour organizations.

  8. [Glass maze in women's leadership].

    Science.gov (United States)

    Barberá Heredia, Ester; Ramos López, Amparo; Candela Agulló, Carlos

    2011-04-01

    Psychological gender discrimination explanations have changed over the past thirty years, becoming more complex in order to obtain a better understanding of the social reality. At the present moment, one of the most interesting research areas is the one referring to the 'glass maze' phenomenon in women's management careers. The main purpose of this work is to reveal the theoretical evolution in an attempt to explain the leadership study from a gender perspective. The consecutive hypotheses, starting with the labour sexual division idea, are becoming more interactive in order to understand the current labour-social situation. Social psychology has underlined the role of beliefs, observed via gender stereotyped roles, prejudiced attitudes against women, sexist and neo-sexist ideology, or masculine, feminine and androgynous identity development. New psychological interpretations insist on the variability of the gender concept, where gender is sometimes observed through men and women's behaviours, and other times through those behaviour expectations. But gender is mainly observed though the power relations between men and women during social interactions in labour organizations. PMID:21504666

  9. Reversão da fibrilação atrial crônica pela técnica do labirinto com aplicação de radiofreqüência e ultra-som transoperatórios Chronic atrial fibrillation reversion by a modified Cox Maze procedure using radiofrequency and transoperatory ultrasound

    Directory of Open Access Journals (Sweden)

    Alexandre Visconti BRICK

    1999-10-01

    Full Text Available A técnica do labirinto, idealizada por Cox (Maze procedure, tem sido utilizada, prioritariamente, para reversão ao ritmo sinusal, em pacientes com fibrilação atrial crônica (FAC e doenças cardíacas de indicação cirúrgica. As incisões atriais, para formação do labirinto, são realizadas por dissecção, seguida de sutura, o que eleva o tempo cirúrgico, aumentando a probabilidade de complicações pós-operatórias. Em vista disso, idealizamos a realização destas linhas pela aplicação transcirúrgica de radiofreqüência (RF ou ultra-som, na parede atrial, o que proporciona uma redução acentuada do tempo cirúrgico. Foram operados, nos anos de 1998 e 1999, 5 pacientes, sendo 3 do sexo feminino, com média de idades de 45,8 anos, portadores de lesão orovalvar mitral e FAC. Durante o ato cirúrgico, os pacientes foram monitorizados com ECG das derivações periféricas. Após a instalação da circulação extracorpórea convencional, sem cardioplegia, foi aberto o átrio direito e aplicado RF, realizando as linhas, de acordo com a técnica do labirinto modificada (Maze procedure. Ao término da aplicação da RF, no átrio direito, observou-se a regularização do R-R da FAC e o aumento das ondas "F", dando a impressão de flutter atípico. Em seguida ao pinçamento da aorta e abertura do átrio esquerdo, procedeu-se ao isolamento da aurícula esquerda e à realização das linhas do átrio esquerdo.Com a liberação da aorta, o coração voltou a contrair-se, espontaneamente, com retorno ao ritmo sinusal, observando-se a contração dos átrios. Após as trocas valvares e redução do átrio esquerdo, o ECG continuava a registrar o ritmo sinusal. Nos 2 últimos pacientes foi utilizado o ultra-som, que nos pareceu, além de facilitar a realização das linhas, produzir lesões mais profundas. Todos evoluíram bem no pós-operatório imediato e tardio, mantendo-se em ritmo sinusal. Com a finalidade de remodelação atrial, usou

  10. Spatial and Nonspatial Escape Strategies in the Barnes Maze

    Science.gov (United States)

    Harrison, Fiona E.; Reiserer, Randall S.; Tomarken, Andrew J.; McDonald, Michael P.

    2006-01-01

    The Barnes maze is a spatial memory task that requires subjects to learn the position of a hole that can be used to escape the brightly lit, open surface of the maze. Two experiments assessed the relative importance of spatial (extra-maze) versus proximal visible cues in solving the maze. In Experiment 1, four groups of mice were trained either…

  11. 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.

  12. 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.

  13. Thermal Ablation for Benign Thyroid Nodules: Radiofrequency and Laser

    OpenAIRE

    Baek, Jung Hwan; Lee, Jeong Hyun; Valcavi, Roberto; Pacella, Claudio M.; Rhim, Hyunchul; Na, Dong Gyu

    2011-01-01

    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.

  14. Factors related to sinus rhythm at discharge after radiofrequency ablation of permanent atrial fibrillation in patients undergoing mitral valve surgery.

    Science.gov (United States)

    Rostagno, Carlo; Gelsomino, Sandro; Capecchi, Irene; Rossi, Alessandra; Montesi, Gian Franco; Stefàno, Pier Luigi

    2016-04-01

    Late recovery of sinus rhythm is unusual in patients with permanent AF treated by (radiofrequency) RF maze procedure during mitral valve surgery. Identification of clinical and instrumental preoperative factors predictive of early success of RF ablation in patients with permanent AF undergoing mitral valve surgery may improve selection of subjects to obtain long-term results. Hundred and thirty consecutive patients with permanent AF and mitral valve disease underwent modified RF maze procedure during concomitant mitral valve surgery. Rheumatic valve disease (61 pts) and mitral valve prolapse (41 pts) were the more common aetiology of valve abnormalities. Mitral valve replacement was performed in 54 % of patients and mitral valve repair in the remaining 46 %. Four patients died after surgery. At discharge, 87 patients (69 %) were in sinus rhythm (group 1) and 43 patients in AF persisted (group 2). At an average 24-month follow-up, sinus rhythm was present in 67 % of patients, and 33 % were in atrial fibrillation. In this period, late recovery of sinus rhythm was observed only in five patients, while eight discharged in sinus rhythm developed again atrial fibrillation. Among preoperative parameters at univariate analysis female sex, atrial fibrillation >24 months, left atrial diameter >54 mm, left atrial area >24 cm(2), rheumatic valve disease and NYHA class were associated with persistence of AF. At Cox regression multivariate analysis, increased left atrial area (OR 1.07 per unit increase-95 % CI 1.01-1.131) and rheumatic aetiology of valve disease (OR 4.52, 95 % CI 1.65-12.4) were associated with persistence of AF at hospital discharge. Persistence of AF after RF ablation in patients undergoing mitral valve surgery is related to aetiology, e.g. rheumatic valve disease, and to increasing left atrial diameter. Due to low rate of late recovery of sinus rhythm, indication to RF ablation associated with MV surgery should be carefully considered in patients with large

  15. Cardiac Remodeling After Atrial Fibrillation Ablation

    Directory of Open Access Journals (Sweden)

    Li-Wei Lo, MD; Shih-Ann Chen, MD

    2013-06-01

    Full Text Available Radiofrequency catheter ablation procedures are considered a reasonable option for patients with symptomatic, drug refractory atrial fibrillation (AF. Ablation procedures have been reported to effectively restore sinus rhythm and provide long-term relief of symptoms. Both electrical and structural remodeling occurs with AF. A reversal of the electrical remodeling develops within 1 week after restoration to sinus rhythm following the catheter ablation. The recovery rate is faster in the right atrium than the left atrium. Reverse structural remodeling takes longer and is still present 2 to 4 months after restoration of sinus rhythm. The left atrial transport function also improves after successful catheter ablation of AF. Left atrial strain surveys from echocardiography are able to identify patients who respond to catheter ablation with significant reverse remodeling after ablation. Pre-procedural delayed enhancement magnetic resonance imaging is also able to determine the degree of atrial fibrosis and is another tool to predict the reverse remodeling after ablation. The remodeling process is complex if recurrence develops after ablation. Recent evidence shows that a combined reverse electrical and structural remodeling occurs after ablation of chronic AF when recurrence is paroxysmal AF. Progressive electrical remodeling without any structural remodeling develops in those with recurrence involving chronic AF. Whether progressive atrial remodeling is the cause or consequence during the recurrence of AF remains obscure and requires further study.

  16. Evaluating the Sensitivity of the Maze as an Index of Reading Proficiency for Students Who Are Severely Deficient in Reading.

    Science.gov (United States)

    Faykus, Suzanne P.; McCurdy, Barry L.

    1998-01-01

    The sensitivity of two curriculum-based measurement procedures, maze (a modified cloze procedure), and oral reading, were evaluated with six students with mental retardation and concomitant emotional/behavioral disorders. Although teacher acceptability of the two procedures was equal, ideographic comparisons revealed oral reading fluency to be a…

  17. 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…

  18. 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...

  19. Analysis of iodinated contrast delivered during thermal ablation: is material trapped in the ablation zone?

    Science.gov (United States)

    Wu, Po-hung; Brace, Chris L.

    2016-08-01

    Intra-procedural contrast-enhanced CT (CECT) has been proposed to evaluate treatment efficacy of thermal ablation. We hypothesized that contrast material delivered concurrently with thermal ablation may become trapped in the ablation zone, and set out to determine whether such an effect would impact ablation visualization. CECT images were acquired during microwave ablation in normal porcine liver with: (A) normal blood perfusion and no iodinated contrast, (B) normal perfusion and iodinated contrast infusion or (C) no blood perfusion and residual iodinated contrast. Changes in CT attenuation were analyzed from before, during and after ablation to evaluate whether contrast was trapped inside of the ablation zone. Visualization was compared between groups using post-ablation contrast-to-noise ratio (CNR). Attenuation gradients were calculated at the ablation boundary and background to quantitate ablation conspicuity. In Group A, attenuation decreased during ablation due to thermal expansion of tissue water and water vaporization. The ablation zone was difficult to visualize (CNR  =  1.57  ±  0.73, boundary gradient  =  0.7  ±  0.4 HU mm-1), leading to ablation diameter underestimation compared to gross pathology. Group B ablations saw attenuation increase, suggesting that iodine was trapped inside the ablation zone. However, because the normally perfused liver increased even more, Group B ablations were more visible than Group A (CNR  =  2.04  ±  0.84, boundary gradient  =  6.3  ±  1.1 HU mm-1) and allowed accurate estimation of the ablation zone dimensions compared to gross pathology. Substantial water vaporization led to substantial attenuation changes in Group C, though the ablation zone boundary was not highly visible (boundary gradient  =  3.9  ±  1.1 HU mm-1). Our results demonstrate that despite iodinated contrast being trapped in the ablation zone, ablation visibility was

  20. Analysis of iodinated contrast delivered during thermal ablation: is material trapped in the ablation zone?

    Science.gov (United States)

    Wu, Po-hung; Brace, Chris L.

    2016-08-01

    Intra-procedural contrast-enhanced CT (CECT) has been proposed to evaluate treatment efficacy of thermal ablation. We hypothesized that contrast material delivered concurrently with thermal ablation may become trapped in the ablation zone, and set out to determine whether such an effect would impact ablation visualization. CECT images were acquired during microwave ablation in normal porcine liver with: (A) normal blood perfusion and no iodinated contrast, (B) normal perfusion and iodinated contrast infusion or (C) no blood perfusion and residual iodinated contrast. Changes in CT attenuation were analyzed from before, during and after ablation to evaluate whether contrast was trapped inside of the ablation zone. Visualization was compared between groups using post-ablation contrast-to-noise ratio (CNR). Attenuation gradients were calculated at the ablation boundary and background to quantitate ablation conspicuity. In Group A, attenuation decreased during ablation due to thermal expansion of tissue water and water vaporization. The ablation zone was difficult to visualize (CNR  =  1.57  ±  0.73, boundary gradient  =  0.7  ±  0.4 HU mm‑1), leading to ablation diameter underestimation compared to gross pathology. Group B ablations saw attenuation increase, suggesting that iodine was trapped inside the ablation zone. However, because the normally perfused liver increased even more, Group B ablations were more visible than Group A (CNR  =  2.04  ±  0.84, boundary gradient  =  6.3  ±  1.1 HU mm‑1) and allowed accurate estimation of the ablation zone dimensions compared to gross pathology. Substantial water vaporization led to substantial attenuation changes in Group C, though the ablation zone boundary was not highly visible (boundary gradient  =  3.9  ±  1.1 HU mm‑1). Our results demonstrate that despite iodinated contrast being trapped in the ablation zone, ablation visibility

  1. Just add water: cannabinoid discrimination in a water T-maze with FAAH(-/-) and FAAH(+/+) mice.

    Science.gov (United States)

    Wiley, Jenny L; Lefever, Timothy W; Pulley, Nikita S; Marusich, Julie A; Cravatt, Benjamin F; Lichtman, Aron H

    2016-08-01

    Incomplete overlap in the discriminative stimulus effects of Δ-tetrahydrocannabinol (THC) and the endocannabinoids, anandamide (AEA) and 2-arachidonoylglycerol has been reported in food-reinforced tasks. The aim of this study was to examine cannabinoid discriminative stimulus effects in a nonappetitive procedure. Adult male mice lacking the gene for AEA's major metabolic enzyme, fatty acid amide hydrolase (FAAH), and FAAH mice were trained to discriminate THC or AEA in a water T-maze, in which the response was swimming to an escape platform on the injection-appropriate side. JZL184, a monoacylglycerol lipase inhibitor, was also tested. FAAH mice showed faster acquisition than FAAH mice. THC and AEA fully substituted, with only minor cross-procedure potency variations. Incomplete substitution of JZL184 was observed in THC-trained FAAH mice in the water-maze task, as contrasted with full substitution in a food-reinforced nose-poke procedure. Stress-induced changes in AEA and/or 2-arachidonoylglycerol concentrations in the brain may have mediated this attenuation. JZL184 also partially substituted in AEA-trained FAAH mice in the water maze, suggesting incomplete overlap in the stimulus effects of AEA and JZL184. Through the use of a novel water-maze procedure, the present study supports the work of previous behavioral pharmacologists in showing the robustness of the discrimination paradigm. PMID:27385208

  2. 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…

  3. A randomized study of combining maze surgery for atrial fibrillation with mitral valve surgery

    NARCIS (Netherlands)

    Jessurun, ER; Van Hemel, NM; Defauw, JJ; De La Riviere, AB; Stofmeel, MAM; Kingma, JH; Ernst, JMPG

    2003-01-01

    Aim Mitral valve surgery seldom suppresses atrial fibrillation (AF), present prior to surgery. Maze III surgery eliminates AF in >80% of cases, the reason why combining this procedure with mitral valve surgery in patients with AF seems worthwhile. We prospectively studied the outcome of combining th

  4. Acute fatal pulmonary vein occlusion after catheter ablation of atrial fibrillation

    DEFF Research Database (Denmark)

    Nilsson, Brian; Chen, Xu; Pehrson, Steen;

    2004-01-01

    the ablation procedure. Selective autopsy of the left lung revealed diffuse alveolar damage, disseminated intravascular coagulation, multiple thrombi formation, and haemorrhagic infarctions. CONCLUSIONS: PV stenosis may occur very early after the ablation procedure. Delayed diagnosis can be fatal. The early...

  5. Monitoring of tumor radio frequency ablation using derivative spectroscopy

    NARCIS (Netherlands)

    Spliethoff, J.W.; Tanis, E.; Evers, Daniel James; Hendriks, B.H.; Prevoo, W.; Ruers, T.J.M.

    2014-01-01

    Despite the widespread use of radio frequency (RF) ablation, an effective way to assess thermal tissue damage during and after the procedure is still lacking. We present a method for monitoring RF ablation efficacy based on thermally induced methemoglobin as a marker for full tissue ablation. Diffus

  6. Quantifying Local Stiffness Variations in Radiofrequency Ablations with Dynamic Indentation

    OpenAIRE

    DeWall, Ryan J.; Varghese, Tomy; Brace, Christopher L.

    2011-01-01

    Elastographic imaging can be used to monitor ablation procedures, however confident and clear determination of the ablation boundary is essential to ensure complete treatment of the pathological target. To investigate the potential for ablation boundary representation on elastographic images, local variations in the viscoelastic properties in radiofrequency ablated regions that were formed in vivo in porcine liver tissue were quantified using dynamic indentation. Spatial stiffness maps were t...

  7. Percutaneous thermal ablation of renal neoplasms

    International Nuclear Information System (INIS)

    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

  8. 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.

  9. CTS Trials Network: Surgical ablation of atrial fibrillation during mitral valve surgery - many questions unanswered.

    Science.gov (United States)

    Afifi, Ahmed

    2015-01-01

    A disease that is associated with stroke and mortality, atrial fibrillation (AF) complicates 30 to 50% of mitral valve disease patients admitted for surgery.(1) Since the introduction of the Cox maze III procedure in 1992 many efforts have been made to come up with modified lesion sets and/or energy sources to surgically treat AF. This lead to the recently published American Heart Association (AHA)- American College of Cardiology (ACC)-Heart Rhythm Society (HRS) guidelines(2) stating that it is reasonable to perform atrial fibrillation ablation in selected patients undergoing other types of cardiac surgery. The effectiveness of different techniques in conversion to sinus rhythm and the clinical impact of freedom from AF remain a question. The CTS Trials Network have undertaken a trial to answer these questions. The first year results of their randomized trial comparing AF ablation at the time of mitral valve surgery with mitral valve surgery alone were published recently in The New England Journal of Medicine.(3).

  10. Studies of ablation pressure, ablative acceleration and ablative implosions

    International Nuclear Information System (INIS)

    Time and space resolved X-ray spectroscopy have been used to measure ablation rate and ablation pressure on plane targets irradiated by the first and second harmonics of Nd glass laser light. Streaked X-ray shadowgraphy has been applied to the study of ablatively imploded spherical shell targets uniformly irradiated by six 1.05 μm laser beams. The results give a direct measurement of shell acceleration and thus of ablation pressure and show evidence of fluid instability increasing as the shell ratio is varied from 10 to 100. A direct determination of implosion core density is also obtained. (author)

  11. Advances in Imaging for Atrial Fibrillation Ablation

    International Nuclear Information System (INIS)

    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

  12. Development of a 2D laser ablation inductively coupled plasma mass spectrometry mapping procedure for mercury in maize (Zea mays L.) root cross-sections

    International Nuclear Information System (INIS)

    Graphical abstract: -- Highlights: •LA-ICP-MS mapping to study the distribution of Hg in plant root cross-sections. •Sorption of LA-generated Hg vapour leads to serious memory effects. •Spot analysis with a delay time of 10 s in between spots alleviates memory effects. •Ablation straight through the sample simplifies calibration. •Hg2+ does not cross the endodermal root barrier of maize plants. -- Abstract: A LA-ICP-MS method based on a 213 nm Nd:YAG laser and a quadrupole ICP-MS has been developed for mapping of mercury in root cross-sections of maize (Zea mays L.) to investigate the mechanism of mercury uptake from soil and its potential translocation to the edible parts. Conventional rastering was found to be unusable due to sorption of mercury onto the internal parts of the LA device, giving rising to memory effects resulting in serious loss of resolution and inaccurate quantification. Spot analysis on a virtual grid on the surface of the root sections using washout times of 10 s in between spots greatly alleviated problems related to these memory effects. By ablating straight through the root sections on a poly(methyl methacrylate) support the calibration process was simplified as internal standardization and matrix-matching could be circumvented. Mercury-spiked freeze-drying embedding medium, sectioned similarly to the root sections, was used for the preparation of the standards. Standards and root sections were subjected to spot analysis using the following operational parameters: beam diameter, 15 μm; laser fluence, 2.5 J cm−2; repetition rate, 20 Hz; dwell time, 1 s; acquisition time, 0.1 s. The mercury peaks for standards and roots sections could be consistently integrated for quantification and construction of the 2D mercury maps for the root sections. This approach was successfully used to investigate the mercury distribution in root sections of maize grown in soil spiked to a level of 50 mg kg−1 DW HgCl2. It was found that at given Hg

  13. Development of a 2D laser ablation inductively coupled plasma mass spectrometry mapping procedure for mercury in maize (Zea mays L.) root cross-sections

    Energy Technology Data Exchange (ETDEWEB)

    Debeljak, Marta [Analytical Chemistry Laboratory, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana (Slovenia); Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna Pot 111, SI-1000 Ljubljana (Slovenia); Elteren, Johannes T. van, E-mail: elteren@ki.si [Analytical Chemistry Laboratory, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana (Slovenia); Vogel-Mikuš, Katarina [Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna Pot 111, SI-1000 Ljubljana (Slovenia)

    2013-07-17

    Graphical abstract: -- Highlights: •LA-ICP-MS mapping to study the distribution of Hg in plant root cross-sections. •Sorption of LA-generated Hg vapour leads to serious memory effects. •Spot analysis with a delay time of 10 s in between spots alleviates memory effects. •Ablation straight through the sample simplifies calibration. •Hg{sup 2+} does not cross the endodermal root barrier of maize plants. -- Abstract: A LA-ICP-MS method based on a 213 nm Nd:YAG laser and a quadrupole ICP-MS has been developed for mapping of mercury in root cross-sections of maize (Zea mays L.) to investigate the mechanism of mercury uptake from soil and its potential translocation to the edible parts. Conventional rastering was found to be unusable due to sorption of mercury onto the internal parts of the LA device, giving rising to memory effects resulting in serious loss of resolution and inaccurate quantification. Spot analysis on a virtual grid on the surface of the root sections using washout times of 10 s in between spots greatly alleviated problems related to these memory effects. By ablating straight through the root sections on a poly(methyl methacrylate) support the calibration process was simplified as internal standardization and matrix-matching could be circumvented. Mercury-spiked freeze-drying embedding medium, sectioned similarly to the root sections, was used for the preparation of the standards. Standards and root sections were subjected to spot analysis using the following operational parameters: beam diameter, 15 μm; laser fluence, 2.5 J cm{sup −2}; repetition rate, 20 Hz; dwell time, 1 s; acquisition time, 0.1 s. The mercury peaks for standards and roots sections could be consistently integrated for quantification and construction of the 2D mercury maps for the root sections. This approach was successfully used to investigate the mercury distribution in root sections of maize grown in soil spiked to a level of 50 mg kg{sup −1} DW HgCl{sub 2}. It was

  14. Clustering for Improved Learning in Maze Traversal Problem

    CERN Document Server

    White, Eddie

    2009-01-01

    The maze traversal problem (finding the shortest distance to the goal from any position in a maze) has been an interesting challenge in computational intelligence. Recent work has shown that the cellular simultaneous recurrent neural network (CSRN) can solve this problem for simple mazes. This thesis focuses on exploiting relevant information about the maze to improve learning and decrease the training time for the CSRN to solve mazes. Appropriate variables are identified to create useful clusters using relevant information. The CSRN was next modified to allow for an additional external input. With this additional input, several methods were tested and results show that clustering the mazes improves the overall learning of the traversal problem for the CSRN.

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

    Directory of Open Access Journals (Sweden)

    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.

  16. Dabigatran in the peri-procedural period for ablation of atrial fibrillation%达比加群酯在心房颤动消融围术期的应用

    Institute of Scientific and Technical Information of China (English)

    潘文麒; 胡文瑛; 林长坚; 张凝; 凌天佑; 吴立群

    2015-01-01

    目的 探讨达比加群酯在心房颤动(房颤)消融围术期抗凝治疗的有效性和安全性.方法 2014年1月至10月在上海交通大学医学院附属瑞金医院共入选进行房颤消融术患者60例,根据围术期抗凝用药不同分为两组,其中华法林组30例,达比加群酯组30例,比较两组患者用药的有效性和安全性.结果 两组患者共有11例发生大小并发症(18.3%).在达比加群酯组中没有严重出血,华法林组中严重出血1例,但两组相比差异无统计学意义(0对3.3%,P>0.05);在达比加群酯组中轻微出血4例,华法林组中轻微出血6例,两组相比差异无统计学意义(13.3%对20%,P>0.05).两组患者均无血栓栓塞事件发生.结论 达比加群酯在房颤消融围术期抗凝治疗与华法林同样有效和安全,可以作为华法林的替代药物.%Objective To evaluated the efficacy and safety of peri-procedural dabigatran in atrial fibrillation(AF) ablation.Methods A total of 60 patients who underwent AF ablation,including 30 patients from Ruijin Hospital,Shanghai Jiaotong University,who received dabigatran(group D)and 30 patients who received warfarin(group W),were evaluated.Results There was no significant difference between the two groups in the incidence of major bleeding(no case of intracranial bleeding in the D group and one case of intracranial bleeding in the W group,0% vs.3.3%,P>0.05)or minor bleeding(four cases in the D group vs.six in the W group,13.3% vs.20%,P>0.05).There were no acute thromboembolic complications in either group.Conclusion Peri-procedural anticoagulation therapy with dabigatran for ablation of AF was equally safe and effective compared with warfarin.Dabigatran appears to be useful as an alternative anticoagulant therapy to warfarin for AF ablation.

  17. Atrioventricular Junction Ablation for Atrial Fibrillation.

    Science.gov (United States)

    Patel, Dilesh; Daoud, Emile G

    2016-04-01

    Atrioventricular junction (AVJ) ablation is an effective therapy in patients with symptomatic atrial fibrillation who are intolerant to or unsuccessfully managed with rhythm control or medical rate control strategies. A drawback is that the procedure mandates a pacing system. Overall, the safety and efficacy of AVJ ablation is high with a majority of the patients reporting significant improvement in symptoms and quality-of-life measures. Risk of sudden cardiac death after device implantation is low, especially with an appropriate postprocedure pacing rate. Mortality benefit with AVJ ablation has been shown in patients with heart failure and cardiac resynchronization therapy devices. PMID:26968669

  18. How I do it: Radiofrequency ablation

    International Nuclear Information System (INIS)

    Over the past decade, image-guided tumor ablation using thermal energy has emerged as a promising technique for treating focal, primary or secondary, nonoperable tumors. Radiofrequency ablation (RFA) is minimally invasive and requires less resources, time, and recovery period and is, moreover, relatively inexpensive. RFA has been used to treat tumors located in the liver, lung, bone, kidneys, brain, thyroid, breast, and pancreas. This article will describe how to choose an appropriate case; precisely place the needle into the tumor; the precautions to be taken before, during, and after the procedure; probable complications; and the follow-up of patients undergoing ablation

  19. Totally thorascopic surgical ablation of persistent AF and long-standing persistent atrial fibrillation using the "Dallas" lesion set.

    Science.gov (United States)

    Edgerton, James R; Jackman, Warren M; Mahoney, Cecile; Mack, Michael J

    2009-12-01

    Minimally invasive surgery consisting of bipolar radiofrequency pulmonary vein (PV) isolation and limited ganglionated plexus ablation is effective in eliminating atrial fibrillation (AF) in patients with paroxysmal AF but is less effective in those with persistent AF or long-standing persistent AF. The purpose of this study was examine the results of minimally invasive surgery incorporating an additional set of radiofrequency ablation lines replicating a left-sided Cox maze III procedure. Thirty patients with persistent AF (n = 10) or long-standing persistent AF (n = 20) underwent minimally invasive surgery with an extended lesion set and PV isolation for a minimum follow-up of 6 months. Linear lesions were created at the roof line, at the anterior line, and between the roof line and the left atrial appendage. All patients underwent limited ganglionated plexus ablation and left atrial appendage excision as well as PV isolation verification. Block across the roof and anterior lines was confirmed in 29 (96.6%) of the 30 patients. Follow-up included 2-week event monitoring with auto-trigger in 21 patients, pacemaker interrogation in 8, and ECG in 1 who was in AF and refused longer-term monitoring. No operative mortality or major morbidity occurred. At 6 months, 24 (80%) of the 30 patients were free of AF: 15 (75%) with long-standing persistent AF and 9 (90%) with persistent AF. Among the six failures, burden of AF was low: one had 1 episode >15 seconds, two had 4 episodes, one had 6 episodes, one had >50 episodes, and one had AF on ECG and refused further monitoring. Early results of minimally invasive surgery with a new extended linear lesion set suggest increased efficacy over PV isolation and limited ganglionated plexus ablation in patients with persistent AF or long-standing persistent AF. PMID:19959146

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  1. Barnes maze testing strategies with small and large rodent models.

    Science.gov (United States)

    Rosenfeld, Cheryl S; Ferguson, Sherry A

    2014-02-26

    Spatial learning and memory of laboratory rodents is often assessed via navigational ability in mazes, most popular of which are the water and dry-land (Barnes) mazes. Improved performance over sessions or trials is thought to reflect learning and memory of the escape cage/platform location. Considered less stressful than water mazes, the Barnes maze is a relatively simple design of a circular platform top with several holes equally spaced around the perimeter edge. All but one of the holes are false-bottomed or blind-ending, while one leads to an escape cage. Mildly aversive stimuli (e.g. bright overhead lights) provide motivation to locate the escape cage. Latency to locate the escape cage can be measured during the session; however, additional endpoints typically require video recording. From those video recordings, use of automated tracking software can generate a variety of endpoints that are similar to those produced in water mazes (e.g. distance traveled, velocity/speed, time spent in the correct quadrant, time spent moving/resting, and confirmation of latency). Type of search strategy (i.e. random, serial, or direct) can be categorized as well. Barnes maze construction and testing methodologies can differ for small rodents, such as mice, and large rodents, such as rats. For example, while extra-maze cues are effective for rats, smaller wild rodents may require intra-maze cues with a visual barrier around the maze. Appropriate stimuli must be identified which motivate the rodent to locate the escape cage. Both Barnes and water mazes can be time consuming as 4-7 test trials are typically required to detect improved learning and memory performance (e.g. shorter latencies or path lengths to locate the escape platform or cage) and/or differences between experimental groups. Even so, the Barnes maze is a widely employed behavioral assessment measuring spatial navigational abilities and their potential disruption by genetic, neurobehavioral manipulations, or drug

  2. Use of maze in cyclotron hoppers

    International Nuclear Information System (INIS)

    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 3He 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

  3. Risk analysis on postoperative recurrence of atrial fibrillation after bipolar radiofrequency ablation undergoing open heart procedures%心内直视房颤射频消融术前危险因素与术后转律关系

    Institute of Scientific and Technical Information of China (English)

    韦俊; 张大发; 刘志勇; 陆启同; 刘德森

    2012-01-01

    Objective Surgical radiofrequency (RF) ablation has recently been one of the most effective means to treat chronic atrial fibrillation(AF).However,about 20% to 30% patients have shown recurrence of AF during the follow-up period.This study retrospectively analyzed AF recurrence rate in those patients who underwent valve replacement procedures combined with RF ablation to treat AF in our department during the last three years.We compared the information and clinical date in the sinus rhythm(SR) group with in the AF recurrence group to analyze the relationship between various preoperative risk factors and operation failure.The aim of this study is to provide evidences to select patients who can benefit most from this type of surgery and to reduce their surgical risk and hospital charges.Methods From June 2006 to June 2009,52 patients with rheumatic heart disease (RHD) and chronic AF underwent RF ablation concomitant with valve replacement in our department by a same surgeon with the same method.Preoperative and intraoperative data was retrospectively collected and all patients were followed up longer than six months to determine the type of heart rhythm.Operation failure was defined as showing any rhythm except normal sinus rhythm by electrocardiogram.We divided all patients to the SR grope and AF grope.Univariate and multivariate statistical analysis was used to compare the data between the two groups in pre-,intra- and postoperative period.Results There was only one case in-hospital mortality ( 1.9% ).None mortality,re-exploration for bleeding and pacemaker implantation for malignant arrhythmia was shown during the mean follow-up period of 14 months (9-35 months).At the last follow-up,sinus rhythm was shown in 71.2% (37/52) patients.In univariaye analysis,the left atrial diameter,AF duration,left ventricular end diastolic volume and aortic cross-clamp were predictors of recurrence of AF.Age,left ventricular ejection factor,cardiopulmonary bypass time showed

  4. Solving mazes with memristors: A massively parallel approach

    Science.gov (United States)

    Pershin, Yuriy V.; di Ventra, Massimiliano

    2011-10-01

    Solving mazes is not just a fun pastime: They are prototype models in several areas of science and technology. However, when maze complexity increases, their solution becomes cumbersome and very time consuming. Here, we show that a network of memristors—resistors with memory—can solve such a nontrivial problem quite easily. In particular, maze solving by the network of memristors occurs in a massively parallel fashion since all memristors in the network participate simultaneously in the calculation. The result of the calculation is then recorded into the memristors’ states and can be used and/or recovered at a later time. Furthermore, the network of memristors finds all possible solutions in multiple-solution mazes and sorts out the solution paths according to their length. Our results demonstrate not only the application of memristive networks to the field of massively parallel computing, but also an algorithm to solve mazes, which could find applications in different fields.

  5. A review of the safety aspects of radio frequency ablation

    Directory of Open Access Journals (Sweden)

    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.

  6. Neuropsychological Decline After Catheter Ablation of Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Schwarz, N

    2011-09-01

    Full Text Available The article “Neuropsychological decline after cath- eter ablation of atrial fibrillation” by Schwarz et al. is the first publication that focused on cognitive side effects of elective circumferential pulmonary vein isolation (PVI.1 Adverse neuropsychological changes after left atrial catheter ablation, as report- ed in this paper, were found in verbal memory and the result, conjoined with ischemic brain lesions, might represent cerebral side-effects of the ablation procedure.

  7. Neural Ablation and Regeneration in Pain Practice.

    Science.gov (United States)

    Choi, Eun Ji; Choi, Yun Mi; Jang, Eun Jung; Kim, Ju Yeon; Kim, Tae Kyun; Kim, Kyung Hoon

    2016-01-01

    A nerve block is an effective tool for diagnostic and therapeutic methods. If a diagnostic nerve block is successful for pain relief and the subsequent therapeutic nerve block is effective for only a limited duration, the next step that should be considered is a nerve ablation or modulation. The nerve ablation causes iatrogenic neural degeneration aiming only for sensory or sympathetic denervation without motor deficits. Nerve ablation produces the interruption of axonal continuity, degeneration of nerve fibers distal to the lesion (Wallerian degeneration), and the eventual death of axotomized neurons. The nerve ablation methods currently available for resection/removal of innervation are performed by either chemical or thermal ablation. Meanwhile, the nerve modulation method for interruption of innervation is performed using an electromagnetic field of pulsed radiofrequency. According to Sunderland's classification, it is first and foremost suggested that current neural ablations produce third degree peripheral nerve injury (PNI) to the myelin, axon, and endoneurium without any disruption of the fascicular arrangement, perineurium, and epineurium. The merit of Sunderland's third degree PNI is to produce a reversible injury. However, its shortcoming is the recurrence of pain and the necessity of repeated ablative procedures. The molecular mechanisms related to axonal regeneration after injury include cross-talk between axons and glial cells, neurotrophic factors, extracellular matrix molecules, and their receptors. It is essential to establish a safe, long-standing denervation method without any complications in future practices based on the mechanisms of nerve degeneration as well as following regeneration. PMID:26839664

  8. Image-Guided Spinal Ablation: A Review.

    Science.gov (United States)

    Tsoumakidou, Georgia; Koch, Guillaume; Caudrelier, Jean; Garnon, Julien; Cazzato, Roberto Luigi; Edalat, Faramarz; Gangi, Afshin

    2016-09-01

    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. PMID:27329231

  9. 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.

  10. 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.)

  11. Imaging in percutaneous ablation for atrial fibrillation

    International Nuclear Information System (INIS)

    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.)

  12. Development of procedures and instrumentation for use of the Nd:YAG laser in the ablation of metastases from colorectal cancer

    Science.gov (United States)

    Bartels, Kenneth E.; Mellow, Mark H.; Kostolich, Marilyn; Henry, George A.; Barnes, Bradley R.; Durville, Frederic M.; Schafer, Steven A.; Krasinski, Jerzy S.; Powell, Richard C.

    1992-06-01

    While many colon cancers are curable, curability relates closely to stage. Once disease is spread beyond the confines of the colon and adjacent lymph nodes, cure is clearly the exception rather than the rule. Recently, surgical resection of solitary liver metastases has been effective in treatment of colon cancer, producing long term survival in approximately 20% of treatable patients. Surgery, however, is technically complex and there is a high perioperative morbidity and substantial perioperative mortality. For patients with multiple hepatic metastases in whom surgical extirpation is not possible, the outlook is dismal. Other modalities including chemotherapy have also resulted in limited success. Recently, a number of investigators have evaluated the effect of low power interstitial Nd:YAG laser irradiation for inducing hyperthermia and coagulative necrosis is hepatic tissue. In treating multiple or large hepatic metastases, the use of a lower power (1 - 5 watts), long duration (50 - 2400 seconds), single fiber laser delivery system has limitations. A computer controlled continuous wave Nd:YAG (1064 nm) laser system using a single fiber 'coupled' to a multiple array of fibers (4 to 6) has been developed for the delivery of low power laser irradiation to hepatic tissue. The advantage of laser energy being delivered simultaneously through multiple fibers is that it expands the area of tissue that can be treated over a given time. Through the use of interventional techniques including percutaneous ultrasound and/or CAT scan directed treatment, laser induced interstitial hyperthermia for large or multiple metastatic lesions could be initiated without the morbidity associated with open surgical procedures.

  13. Radiofrequency Ablation of Thyroid Nodules: Basic Principles and Clinical Application

    Directory of Open Access Journals (Sweden)

    Ji Hoon Shin

    2012-01-01

    Full Text Available Radiofrequency (RF ablation has been gaining popularity as a minimally invasive treatment for benign thyroid nodules regardless of the extent of the solid component. RF ablation of benign nodules demonstrated volume reductions of 33–58% after one month and 51–85% after six months, while solving nodule-related clinical problems. RF ablation has recently shown positive short-term results for locoregional control as well as symptom improvement in patients with recurrent thyroid cancers. This paper reviews the basic physics, indications, patient preparation, devices, procedures, clinical results, and complications of RF ablation.

  14. Atrium-atrioventricular node block: an unusual complication during catheter ablation of persistent atrial fibrillation

    Institute of Scientific and Technical Information of China (English)

    MIAO Cheng-long; SANG Cai-hua; DONG Jian-zeng; MA Chang-sheng

    2011-01-01

    Ablation of persistent atrial fibrillation is still a challenge for the ablationist. Extensive ablation is required under some conditions and could lead to some unintended complications. Here we report a case of atrium-atrioventricular node block complicating multiple catheter ablation procedures for persistent atrial fibrillation. After extensive ablation, including circumferential pulmonary vein ablation, linear ablation at the left atrial roof, mitral isthmus, atrial septum, cavotricuspid isthmus, and complex fractionated atrial electrogram ablation, conduction obstacle was found, and sinus impulse could not travel from the right atrium, atrial septum and left atrium to atrioventricular node. The case indicated that intensive ablation at some key sites, especially the interatrial septum, should be careful during ablation of atrial fibrillation.

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

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jung Bin; Rhim, Hyunchul; Kim, Yongsoo; Koh, Byung Hee; Cho, On Koo; Seo, Heung Suk; Lee, Seung Ro [College of Medicine, Hanyang University, Seoul (Korea, Republic of)

    2000-07-01

    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)

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

    International Nuclear Information System (INIS)

    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)

  17. 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.

  18. Lung Ablation: Whats New?

    Science.gov (United States)

    Xiong, Lillian; Dupuy, Damian E

    2016-07-01

    Lung cancer had an estimated incidence of 221,200 in 2015, making up 13% of all cancer diagnoses. Tumor ablation is an important treatment option for nonsurgical lung cancer and pulmonary metastatic patients. Radiofrequency ablation has been used for over a decade with newer modalities, microwave ablation, cryoablation, and irreversible electroporation presenting as additional and possibly improved treatment options for patients. This minimally invasive therapy is best for small primary lesions or favorably located metastatic tumors. These technologies can offer palliation and sometimes cure of thoracic malignancies. This article discusses the current available technologies and techniques available for tumor ablation. PMID:27050331

  19. Feasibility and safety of remote-controlled magnetic navigation for ablation of atrial fibrillation.

    Science.gov (United States)

    Katsiyiannis, William T; Melby, Daniel P; Matelski, Jayme L; Ervin, Vanessa L; Laverence, Kerri L; Gornick, Charles C

    2008-12-15

    Radiofrequency ablation for atrial fibrillation (AF) involves complex catheter manipulation resulting in prolonged procedure time and fluoroscopy exposure. Remote magnetic navigation (RMN) represents a novel approach toward improving the ability to perform complex ablation. Forty patients underwent ablation for AF, 20 using RMN (NIOBE II, Stereotaxis, Inc) with a 4-mm-tip magnetic catheter (Celsius, Biosense Webster) and 20 using a conventional 8-mm-tip bidirectional ablation catheter (Blazer, Boston Scientific). All patients underwent a combined wide area circumferential ablation and segmental pulmonary vein (PV) isolation using a circular mapping catheter and cavotricuspid isthmus ablation for right atrial flutter. The procedural end point was PV entrance block. There was no difference in atrial size, left ventricular systolic function, or type of AF between groups. PV entrance block was achieved in all patients. Mean procedure time was 279 +/- 60 minutes in the conventional group versus 209 +/- 56 minutes in the RMN group (p RMN group (p RMN group free from clinical AF and off antiarrhythmic drugs (p = NS). There were 2 additional ablations performed for atypical atrial flutter in the conventional group and 3 in the RMN group (p = ns). Ablation catheter char formation was not observed. There were no procedural complications. In conclusion, radiofrequency ablation of AF performed with RMN is safe and feasible. Compared with conventional hand-navigated ablation, RMN ablation results in similar clinical outcomes with decreased fluoroscopy and procedure times.

  20. Catheter ablation of atrial fibrillation in a patient with dextrocardia: what is the challenge?

    Institute of Scientific and Technical Information of China (English)

    WANG Xin-hua; SHI Hai-feng; HAN Bing; TAN Hong-wei; JIANG Wei-feng; LIU Xu

    2010-01-01

    @@ Catheter ablation has been an established strategy for treating paroxysmal atrial fibrillation (AF).Pulmonary vein isolation is the predominant approach of catheter ablation. This procedure is characterized as transseptal catheterization and point-by-point ablation around the ipsilateral pulmonary veins (PVs). Although catheter ablation can be safely performed in a heart with normal structures, it may be challenging to be performed in a dextrocardia.

  1. 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.

  2. 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

  3. 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.

  4. Ablation of Atrial Fibrillation: Patient Selection, Periprocedural Anticoagulation, Techniques, and Preventive Measures After Ablation.

    Science.gov (United States)

    Link, Mark S; Haïssaguerre, Michel; Natale, Andrea

    2016-07-26

    Atrial fibrillation (AF) is the most common arrhythmia encountered by cardiologists and is a major cause of morbidity and mortality. Risk factors for AF include age, male sex, genetic predisposition, hypertension, diabetes mellitus, sleep apnea, obesity, excessive alcohol, smoking, hyperthyroidism, pulmonary disease, air pollution, heart failure, and possibly excessive exercise. The management of AF involves decisions about rate versus rhythm control. Asymptomatic patients are generally managed with rate control and anticoagulation. Symptomatic patients will desire rhythm control. Rhythm control options are either antiarrhythmic agents or ablation, with each having its own risks and benefits. Ablation of AF has evolved from a rare and complex procedure to a common electrophysiological technique. Selection of patients to undergo ablation is an important aspect of AF care. Patients with the highest success rates of ablation are those with normal structural hearts and paroxysmal AF, although those with congestive heart failure have the greatest potential benefit of the procedure. Although pulmonary vein isolation of any means/energy source is the approach generally agreed on for those with paroxysmal AF, optimal techniques for the ablation of nonparoxysmal AF are not yet clear. Anticoagulation reduces thromboembolic complications; the newer anticoagulants have eased management for both the patient and the cardiologist. Aggressive management of modifiable risk factors (hypertension, diabetes mellitus, sleep apnea, obesity, excessive alcohol, smoking, hyperthyroidism, pulmonary disease, air pollution, and possibly excessive exercise) after ablation reduces the odds of recurrent AF and is an important element of care. PMID:27462054

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

    Science.gov (United States)

    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.

  6. 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.)

  7. Delayed Development of Pneumothorax After Pulmonary Radiofrequency Ablation

    International Nuclear Information System (INIS)

    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.

  8. Collateral damage from Catheter Ablation of Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Wanwarang Wongcharoen, MD

    2013-04-01

    Full Text Available Atrial fibrillation (AF is the most common sustained arrhythmia, contributing to a significant morbidity and mortality. Catheter ablation of the pulmonary veins (PVs and left atrium (LA has been shown to be an effective strategy for the treatment of symptomatic AF. Regardless of technological advances and technique improvement, catheter ablation for AF remains a highly complex procedure and the risk of procedural complications is not negligible. The major complications have been reported to occur in up to 5.2% of procedures. A systematic investigation among 32,569 patients undergoing catheter ablation for AF has demonstrated that mortality is around 0.1%. Nevertheless, the true prevalence of complications is possibly underestimated in retrospective surveys because of recollection bias and other factors. This article will focus on the management of serious complications of catheter AF ablation including PV stenosis, atrioesophageal fistula, cardiac tamponade, stroke and thromboembolic complication

  9. Intelligence-Augmented Rat Cyborgs in Maze Solving

    Science.gov (United States)

    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. PMID:26859299

  10. Mental walking through a complex maze influences lateralized ultradian rhythms.

    Science.gov (United States)

    Meier-Koll, A; Albrecht, U; Neuschwander, D

    1998-12-01

    Subjects of two experimental groups, 10 males and 10 females in each group, explored artificial environments represented by compact city mazes. The mazes, a simple and a complex one, were generated by means of a computer program. After turning the program on, a scene with houses, streets, and alleys appeared on a TV screen. The subjects sat in front of the screen and manoeuvered through the simple or the complex maze with the help of a hand-operated device. Correspondingly the street scenes changed in such a way that the subject had the illusion of a normal pace. Each subject explored one maze for eight hours. Every 15 min. an experimenter interrupted the subject's walk and measured tactile discrimination in either hand. Ultradian periodic variations in the tactile error rate of the right and left hands with periods of 2 or 3 hours are found. They are considered manifestations of endogenous rhythms operating separately in the left and right cerebral hemispheres. As demonstrated in a previous paper, lateralized ultradian rhythms in tactile discrimination are different for males and females when tested under quiet laboratory conditions. The present paper shows that the rhythms are specifically influenced in both sexes by the spatial complexity of an artificial environment (maze). These findings are discussed from an evolutionary point of view.

  11. 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.

  12. Unexplained liver laceration after metastasis radiofrequency ablation

    Institute of Scientific and Technical Information of China (English)

    Esther U(n)a; Javier Trueba; Jose Manuel Montes

    2009-01-01

    Many studies have established the role of radiofrequency (RF) ablation as a minimally invasive treatment for liver metastases. Although relatively safe, several complications have been reported with the increased use of RF ablation. We describe here a case of unexplained liver laceration after a RF procedure. A woman who presented a solitary metachronous liver metastasis underwent RF ablation treatment for this lesion. Six hours later the patient displayed fatigue and pallor.Emergency blood tests showed a haemoglobin level of < 7 g/dL and markedly elevated transaminase levels.A computed tomography examination revealed two areas of liver laceration with haematoma, one of them following the path of the needle and the other leading away from the first. Following a blood transfusion, the patient was haemodynamically stable and completely recovered 24 h later. The patient remained in bed for 1 wk. No surgical intervention was required, and she was discharged 1 wk later.

  13. MR Guided RF Ablation and Thermometery

    Directory of Open Access Journals (Sweden)

    Sara Eskandari

    2009-01-01

    Full Text Available "nIntroduction: Liver metastasis is detected in more than one million people in each year. Only 10% of them are eligible for surgery. Radiofrequency ablation is the most popular local ablation technique for the management of the other 90% of the metastases. Complete ablation of the lesion with a safe margin is the goal of such a local ablative method. There is no routine available technique for monitoring the treatment process. MRI is the only method which can monitor tissue ablation in real time however interaction of radiofrequency energy by MRI acquisition makes it impossible for clinical use. "nMaterials and Methods: In our in-vitro study, the effect of bipolar needles were evaluated on the signal intensity of theliver parenchyma. This evaluation was repeated 15 times. A calibration curve was also calculated from the in-vitro measurement of tissue temperature with an interstitial NTC sensor with dedicated data collecting software written by our team. Finally the correlation between temperature and signal intensity was prepared and during the RF ablation, the temperature map could be created in an almost real time manner. "nResults: Our results show an exponential calibration curve for sensors and a linear reduction of the signal intensities during the RF procedure. "nConclusion: We introduce a method for calibration of the MRI signal intensity with tissue temperature between alternative RF pulses. This method brings MR monitoring as the practical method in clinical use. By this innovative technique it is possible for all the hospitals and clinics to use their routine MR scanner for monitoring this ablative technique without any additional hardware.  

  14. Photoacoustic characterization of radiofrequency ablation lesions

    Science.gov (United States)

    Bouchard, Richard; Dana, Nicholas; Di Biase, Luigi; Natale, Andrea; Emelianov, Stanislav

    2012-02-01

    Radiofrequency ablation (RFA) procedures are used to destroy abnormal electrical pathways in the heart that can cause cardiac arrhythmias. Current methods relying on fluoroscopy, echocardiography and electrical conduction mapping are unable to accurately assess ablation lesion size. In an effort to better visualize RFA lesions, photoacoustic (PA) and ultrasonic (US) imaging were utilized to obtain co-registered images of ablated porcine cardiac tissue. The left ventricular free wall of fresh (i.e., never frozen) porcine hearts was harvested within 24 hours of the animals' sacrifice. A THERMOCOOLR Ablation System (Biosense Webster, Inc.) operating at 40 W for 30-60 s was used to induce lesions through the endocardial and epicardial walls of the cardiac samples. Following lesion creation, the ablated tissue samples were placed in 25 °C saline to allow for multi-wavelength PA imaging. Samples were imaged with a VevoR 2100 ultrasound system (VisualSonics, Inc.) using a modified 20-MHz array that could provide laser irradiation to the sample from a pulsed tunable laser (Newport Corp.) to allow for co-registered photoacoustic-ultrasound (PAUS) imaging. PA imaging was conducted from 750-1064 nm, with a surface fluence of approximately 15 mJ/cm2 maintained during imaging. In this preliminary study with PA imaging, the ablated region could be well visualized on the surface of the sample, with contrasts of 6-10 dB achieved at 750 nm. Although imaging penetration depth is a concern, PA imaging shows promise in being able to reliably visualize RF ablation lesions.

  15. Role of Intracardiac echocardiography in Atrial Fibrillation Ablation

    Directory of Open Access Journals (Sweden)

    Antonio Dello Russo, MD PhD

    2013-04-01

    Full Text Available In the recent years, several new evidences support catheter-based ablation as a treatment modality of atrial fibrillation (AF. Based on a plenty of different applications, intracardiac echocardiography (ICE is now a well-established technology in complex electrophysiological procedures, in particular in AF ablation. ICE contributes to improve the efficacy and safety of such procedures defining the anatomical structures involved in ablation procedures and monitoring in real time possible complications. In particular ICE allows: a correct identification of the endocardial structures; a guidance of transseptal puncture; an assessment of accurate placement of the circular mapping catheter; an indirect evaluation of evolving lesions during radiofrequency (RF energy delivery via visualization of micro and macrobubbles tissue heating; assessment of catheter contact with cardiac tissues. Recently, also the feasibility of the integration of electroanatomical mapping (EAM and intracardiac echocardiography has been demonstrated, combining accurate real time anatomical information with electroanatomical data. As a matter of fact, different techniques and ablation strategies have been developed throughout the years. In the setting of balloon-based ablation systems, recently adopted by an increasing number of centers, ICE might have a role in the choice of appropriate balloon size and to confirm accurate occlusion of pulmonary veins. Furthermore, in the era of minimally fluoroscopic ablation, ICE has successfully provided a contribute in reducing fluoroscopy time. The purpose of this review is to summarize the current applications of ICE in catheter based ablation strategies of atrial fibrillation, focusing-on electronically phased-array ICE.

  16. Hippocampal GluR1 Associates with Behavior in the Elevated Plus Maze and Shows Sex Differences

    OpenAIRE

    Xiang, Xiaojun; Huang, Wen; Haile, Colin N.; Therese A Kosten

    2011-01-01

    The hippocampus is involved in anxiety as well as spatial memory formation and is sexually dimorphic. Female rats typically show less anxiety in elevated plus maze procedure (EPM), a standard animal model of anxiety. Many intracellular proteins, including α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunit GluR1 and the cyclic AMP response element-binding protein (CREB), in hippocampus contribute to memory formation. However, less is known about the roles for hippocam...

  17. Microwave Ablation of Hepatic Malignancy

    OpenAIRE

    Lubner, Meghan G.; Brace, Christopher L.; Ziemlewicz, Tim J.; Hinshaw, J. Louis; Lee, Fred. T.

    2013-01-01

    Microwave ablation is an extremely promising heat-based thermal ablation modality that has particular applicability in treating hepatic malignancies. Microwaves can generate very high temperatures in very short time periods, potentially leading to improved treatment efficiency and larger ablation zones. As the available technology continues to improve, microwave ablation is emerging as a valuable alternative to radiofrequency ablation in the treatment of hepatic malignancies. This article rev...

  18. Aspects of procedural memory are differentially impaired in Huntington's disease.

    Science.gov (United States)

    Bylsma, F W; Brandt, J; Strauss, M E

    1990-01-01

    Procedural memory encompasses several phenomena, including motor and perceptual learning, cognitive rule learning and priming. These subclasses are differentially affected by differing neuropathologies, suggesting their functional independence and reliance upon different neural substrates. To test this hypothesis, performance on a maze learning task was compared in 15 Huntington's disease (HD) patients and 15 normal controls (NC) to assess specific route learning, cognitive skill learning and the effects of route predictability on performance. Results revealed that the HD group: (1) showed normal learning curves for a specific maze route; (2) are deficient in generalizing the cognitive skills across mazes; and, (3) fail to improve performance on a maze with a predictable route relative to mazes with unpredictable routes. These results are interpreted as supporting the independence of procedural memory subclasses. The basal ganglia are suggested as important structures in mediating the ability to generalize skills and appreciate patterned organization in to-be-acted-upon stimuli. PMID:14589688

  19. Moldable cork ablation material

    Science.gov (United States)

    1977-01-01

    A successful thermal ablative material was manufactured. Moldable cork sheets were tested for density, tensile strength, tensile elongation, thermal conductivity, compression set, and specific heat. A moldable cork sheet, therefore, was established as a realistic product.

  20. Ablation of Myocardial Tissue With Nanosecond Pulsed Electric Fields.

    Directory of Open Access Journals (Sweden)

    Fei Xie

    Full Text Available Ablation of cardiac tissue is an essential tool for the treatment of arrhythmias, particularly of atrial fibrillation, atrial flutter, and ventricular tachycardia. Current ablation technologies suffer from substantial recurrence rates, thermal side effects, and long procedure times. We demonstrate that ablation with nanosecond pulsed electric fields (nsPEFs can potentially overcome these limitations.We used optical mapping to monitor electrical activity in Langendorff-perfused New Zealand rabbit hearts (n = 12. We repeatedly inserted two shock electrodes, spaced 2-4 mm apart, into the ventricles (through the entire wall and applied nanosecond pulsed electric fields (nsPEF (5-20 kV/cm, 350 ns duration, at varying pulse numbers and frequencies to create linear lesions of 12-18 mm length. Hearts were stained either with tetrazolium chloride (TTC or propidium iodide (PI to determine the extent of ablation. Some stained lesions were sectioned to obtain the three-dimensional geometry of the ablated volume.In all animals (12/12, we were able to create nonconducting lesions with less than 2 seconds of nsPEF application per site and minimal heating (< 0.2°C of the tissue. The geometry of the ablated volume was smoother and more uniform throughout the wall than typical for RF ablation. The width of the lesions could be controlled up to 6 mm via the electrode spacing and the shock parameters.Ablation with nsPEFs is a promising alternative to radiofrequency (RF ablation of AF. It may dramatically reduce procedure times and produce more consistent lesion thickness than RF ablation.

  1. Ablation of Myocardial Tissue With Nanosecond Pulsed Electric Fields

    Science.gov (United States)

    Xie, Fei; Varghese, Frency; Pakhomov, Andrei G.; Semenov, Iurii; Xiao, Shu; Philpott, Jonathan; Zemlin, Christian

    2015-01-01

    Background Ablation of cardiac tissue is an essential tool for the treatment of arrhythmias, particularly of atrial fibrillation, atrial flutter, and ventricular tachycardia. Current ablation technologies suffer from substantial recurrence rates, thermal side effects, and long procedure times. We demonstrate that ablation with nanosecond pulsed electric fields (nsPEFs) can potentially overcome these limitations. Methods We used optical mapping to monitor electrical activity in Langendorff-perfused New Zealand rabbit hearts (n = 12). We repeatedly inserted two shock electrodes, spaced 2–4 mm apart, into the ventricles (through the entire wall) and applied nanosecond pulsed electric fields (nsPEF) (5–20 kV/cm, 350 ns duration, at varying pulse numbers and frequencies) to create linear lesions of 12–18 mm length. Hearts were stained either with tetrazolium chloride (TTC) or propidium iodide (PI) to determine the extent of ablation. Some stained lesions were sectioned to obtain the three-dimensional geometry of the ablated volume. Results In all animals (12/12), we were able to create nonconducting lesions with less than 2 seconds of nsPEF application per site and minimal heating (< 0.2°C) of the tissue. The geometry of the ablated volume was smoother and more uniform throughout the wall than typical for RF ablation. The width of the lesions could be controlled up to 6 mm via the electrode spacing and the shock parameters. Conclusions Ablation with nsPEFs is a promising alternative to radiofrequency (RF) ablation of AF. It may dramatically reduce procedure times and produce more consistent lesion thickness than RF ablation. PMID:26658139

  2. Contact Force and Atrial Fibrillation Ablation

    Directory of Open Access Journals (Sweden)

    Waqas Ullah; Richard Schilling; Tom Wong

    2016-02-01

    Full Text Available Catheters able to measure the force and vector of contact between the catheter tip and myocardium are now available. Pre-clinical work has established that the degree of contact between the radiofrequency ablation catheter and myocardium correlates with the size of the delivered lesion. Excess contact is associated with steam pops and perforation. Catheter contact varies within the left atrium secondary to factors including respiration, location, atrial rhythm and the trans-septal catheter delivery technology used. Compared with procedures performed without contact force (CF-sensing, the use of this technology has, in some studies, been found to improve complication rates, procedure and fluoroscopy times, and success rates. However, for each of these parameters there are also studies suggesting a lack of difference from the availability of CF data. Nevertheless, CF-sensing technology has been adopted as a standard of care in many institutions. It is likely that use of CF-sensing technology will allow for the optimization of each individual radiofrequency application to maximize efficacy and procedural safety. Recent work has attempted to define what these optimal targets should be, and approaches to do this include assessing for sites of pulmonary vein reconnection after ablation, or comparing the impedance response to ablation. Based on such work, it is apparent that factors including mean CF, force time integral (the area under the force-time curve and contact stability are important determinants of ablation efficacy. Multicenter prospective randomized data are lacking in this field and required to define the CF parameters required to produce optimal ablation.

  3. 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…

  4. 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.

  5. 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.

  6. Mazes and Maps: Can Young Children Find Their Way?

    Science.gov (United States)

    Jirout, Jamie J.; Newcombe, Nora S.

    2014-01-01

    Games provide important informal learning activities for young children, and spatial game play (e.g., puzzles and blocks) has been found to relate to the development of spatial skills. This study investigates 4- and 5-year-old children's use of scaled and unscaled maps when solving mazes, asking whether an important aspect of spatial…

  7. [The olfactory orientation traits of white rats in a maze].

    Science.gov (United States)

    Stol'berg, A M; Grigorian, G E

    1991-01-01

    Some characteristics of olfactory behaviour of albino rats in three-arm maze have been studied. It was found that the olfactory discrimination of different food reinforcements may be elaborated in passages as long as 90 cm. Choice reactions were determined by olfactory, not visual, stimuli on their simultaneous presentation. PMID:1808972

  8. Role of Percutaneous Microwave Ablation in Treatment of Hepatocellular Carcinoma

    Directory of Open Access Journals (Sweden)

    Ahmed Tharwat Sayed *, Sahar M El Fiky*,

    2014-07-01

    Full Text Available Introduction: Hepatocellular carcinoma (HCC is one of the most common malignancies worldwide with an annual occurrence of one million new cases. An etiologic association between HBV infection and the development of HCC has been established. Hepatitis C virus is also proving an important predisposing factor for this malignancy, the use of minimally invasive Percutaneous ablative technique (e.g. Radiofrequency (RF and Microwave ablation (MW has gained great momentum and because of the drawbacks of RF ablation, several groups have successfully proved the efficacious nature of Microwave ablation in the treatment of hepatocellular carcinoma. Aim of the Work: The aim of this work is to highlight the role, the principles and the applications of percutaneous Microwave Ablation in Hepatocellular carcinoma. Methods: The studied group included 30 patients (25 men and 5 women with hepatocellular carcinoma. All patients underwent microwave ablation for the hepatocellular carcinoma. Results: The results of the procedures will be assessed as regarding sizeand enhancement of the lesion (s on triphasic CT abdomen before the procedure and at the follow up at one month as well as the Alpha fetoprotein levels. Conclusion: MWA technique represents a safe, fast and efficacious way to perform hepatic ablation in patients with HCC. Initial results are encouraging; however, longer follow-up is needed for further classification of our results.

  9. Laser ablation of tumors: current concepts and recent developments

    International Nuclear Information System (INIS)

    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.)

  10. AF Termination: the Holy Grail of Persistent AF Ablation?

    Directory of Open Access Journals (Sweden)

    Dennis H. Lau, MBBS

    2010-06-01

    Full Text Available The optimal catheter ablation approach for longstanding persistent atrial fibrillation (AF remains elusive despite significant advances made in our understanding of this arrhythmia. A recent systematic review highlighted the significant variation in procedural success rate both within and between techniques, necessitating repeat ablation procedures and anti-arrhythmic drugs to achieve improved outcomes in those with long-standing persistent AF.1 Indeed, current expert consensus statement recommended ablation beyond ostial pulmonary vein isolation for these patients.2 Despite incorporating various substrate modification techniques which commonly include linear lesions and targeting of complex fractionated electrograms, the reported success rates from various laboratories are still below par to those in paroxysmal AF patients.1 Perhaps the often dilated and chronically remodeled atria in longstanding persistent AF patients harbor complex structural substrates capable of maintaining the arrhythmia beyond amelioration even with extensive catheter ablation in some. Certainly, this reflects our incomplete understanding of the complex mechanisms underlying this arrhythmia.

  11. CT imaging of complications of catheter ablation for atrial fibrillation

    International Nuclear Information System (INIS)

    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

  12. Clinical outcomes of bipolar radiofrequency ablation modified maze procedure for treating atrial fibrillation in patients with left atrial diameter more than 60 mm%左心房内径大于60 mm心房颤动患者行改良迷宫射频消融术的疗效

    Institute of Scientific and Technical Information of China (English)

    邓元子; 李韬; 胡楝; 刘超

    2013-01-01

    目的 评价改良迷宫双极射频消融术在左心房内径>60 mm患者中治疗心房颤动(房颤)的临床疗效.方法 对同一术者在瓣膜置换同期行改良迷宫双极射频消融术并随访9个月以上的患者106例,按左心房内径大小分为两组:观察组左心房内径>60 mm(27例),对照组左心房内径<60 mm(79例).对所有患者进行随访分析,比较两组手术疗效.结果 两组手术并发症发生率比较,差异无统计学意义(P>0.05).观察组术后当日恢复窦性心律23例,心房扑动1例,房颤2例,交界性心律1例,房颤消除率为88.9%.出院时窦性心律22例,心房扑动2例,房颤消除率为88.9%.术后9~12个月窦性心律21例,房颤6例,房颤消除率为77.8%.对照组术后当日恢复窦性心律71例,心房扑动1例,房颤5例,交界性心律2例,房颤消除率为91.1%.术后9~12个月窦性心律70例,房颤9例,房颤消除率为88.6%.随访至术后9~12个月观察组房颤消除率与对照组相比,差异无统计学意义[77.8%(21/27)vs.88.6%(70/79),P>0.05].结论 左心房内径>60 mm的患者行改良迷宫双极射频消融术治疗房颤安全、简便,仍可获得较好的近期疗效.对左心房显著增大的患者,增加左心房后壁消融线路,术后注意避免过高的中心静脉压、维持钾离子浓度在正常高值,有利于提高手术疗效.

  13. CORRECTION OF MYOPIA USING CORNEA SPARING LASIK (ABLATION ON FLAP

    Directory of Open Access Journals (Sweden)

    Nikhilesh

    2015-02-01

    Full Text Available Cornea sparing lasik is useful tool allowing surgeons to preserve the posterior stroma. The study comprised of prospective evaluation of 17 eyes treated with CSL – Cornea Sparing Lasik at Mahatme Eye Bank Eye Hospital , N agpur India. Our results show that the laser ablation on the corneal flap is safe and effective procedure. The refractive , efficacy and safety outcomes were similar to those in routine Lasik ablation on posterior stroma.

  14. Treatment of bone tumours by radiofrequency thermal ablation

    OpenAIRE

    Santiago, Fernando Ruiz; del Mar Castellano García, María; Montes, Jose Luis Martínez; García, Manuel Ruiz; Fernández, Juan Miguel Tristán

    2009-01-01

    Radiofrequency thermal ablation (RFTA) is considered the treatment of choice for osteoid osteomas, in which it has long been safely used. Other benign conditions (chondroblastoma, osteoblastoma, giant cell tumour, etc.) can also be treated by this technique, which is less invasive than traditional surgical procedures. RFTA ablation is also an option for the palliation of localized, painful osteolytic metastatic and myeloma lesions. The reduction in pain improves the quality of life of patient...

  15. Tumor ablation with irreversible electroporation.

    Directory of Open Access Journals (Sweden)

    Bassim Al-Sakere

    Full Text Available We report the first successful use of irreversible electroporation for the minimally invasive treatment of aggressive cutaneous tumors implanted in mice. Irreversible electroporation is a newly developed non-thermal tissue ablation technique in which certain short duration electrical fields are used to permanently permeabilize the cell membrane, presumably through the formation of nanoscale defects in the cell membrane. Mathematical models of the electrical and thermal fields that develop during the application of the pulses were used to design an efficient treatment protocol with minimal heating of the tissue. Tumor regression was confirmed by histological studies which also revealed that it occurred as a direct result of irreversible cell membrane permeabilization. Parametric studies show that the successful outcome of the procedure is related to the applied electric field strength, the total pulse duration as well as the temporal mode of delivery of the pulses. Our best results were obtained using plate electrodes to deliver across the tumor 80 pulses of 100 micros at 0.3 Hz with an electrical field magnitude of 2500 V/cm. These conditions induced complete regression in 12 out of 13 treated tumors, (92%, in the absence of tissue heating. Irreversible electroporation is thus a new effective modality for non-thermal tumor ablation.

  16. Incidence and Cause of Hypertension During Adrenal Radiofrequency Ablation

    International Nuclear Information System (INIS)

    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.

  17. Generalizability Theory Analysis of CBM Maze Reliability in Third- through Fifth-Grade Students

    Science.gov (United States)

    Mercer, Sterett H.; Dufrene, Brad A.; Zoder-Martell, Kimberly; Harpole, Lauren Lestremau; Mitchell, Rachel R.; Blaze, John T.

    2012-01-01

    Despite growing use of CBM Maze in universal screening and research, little information is available regarding the number of CBM Maze probes needed for reliable decisions. The current study extends existing research on the technical adequacy of CBM Maze by investigating the number of probes and assessment durations (1-3 min) needed for reliable…

  18. Transient Ablation of Teflon Hemispheres

    Science.gov (United States)

    Arai, Norio; Karashima, Kei-ichi; Sato, Kiyoshi

    1997-01-01

    For high-speed entry of space vehicles into atmospheric environments, ablation is a practical method for alleviating severe aerodynamic heating. Several studies have been undertaken on steady or quasi-steady ablation. However, ablation is a very complicated phenomenon in which a nonequilibrium chemical process is associated with an aerodynamic process that involves changes in body shape with time. Therefore, it seems realistic to consider that ablation is an unsteady phenomenon. In the design of an ablative heat-shield system, since the ultimate purpose of the heat shield is to keep the internal temperature of the space vehicle at a safe level during entry, the transient heat conduction characteristics of the ablator may be critical in the selection of the material and its thickness. This note presents an experimental study of transient ablation of Teflon, with particular emphasis on the change in body shape, the instantaneous internal temperature distribution, and the effect of thermal expansion on ablation rate.

  19. Power Laser Ablation Symposia

    CERN Document Server

    Phipps, Claude

    2007-01-01

    Laser ablation describes the interaction of intense optical fields with matter, in which atoms are selectively driven off by thermal or nonthermal mechanisms. The field of laser ablation physics is advancing so rapidly that its principal results are seen only in specialized journals and conferences. This is the first book that combines the most recent results in this rapidly advancing field with authoritative treatment of laser ablation and its applications, including the physics of high-power laser-matter interaction. Many practical applications exist, ranging from inertial confinement fusion to propulsion of aerostats for pollution monitoring to laser ignition of hypersonic engines to laser cleaning nanoscale contaminants in high-volume computer hard drive manufacture to direct observation of the electronic or dissociative states in atoms and molecules, to studying the properties of materials during 200kbar shocks developed in 200fs. Selecting topics which are representative of such a broad field is difficu...

  20. Local Ablative Strategies for Ductal Pancreatic Cancer (Radiofrequency Ablation, Irreversible Electroporation): A Review.

    Science.gov (United States)

    Paiella, Salvatore; Salvia, Roberto; Ramera, Marco; Girelli, Roberto; Frigerio, Isabella; Giardino, Alessandro; Allegrini, Valentina; Bassi, Claudio

    2016-01-01

    Pancreatic ductal adenocarcinoma (PDAC) has still a dismal prognosis. Locally advanced pancreatic cancer (LAPC) accounts for the 40% of the new diagnoses. Current treatment options are based on chemo- and radiotherapy regimens. Local ablative techniques seem to be the future therapeutic option for stage-III patients with PDAC. Radiofrequency Ablation (RFA) and Irreversible Electroporation (IRE) are actually the most emerging local ablative techniques used on LAPC. Initial clinical studies on the use of these techniques have already demonstrated encouraging results in terms of safety and feasibility. Unfortunately, few studies on their efficacy are currently available. Even though some reports on the overall survival are encouraging, randomized studies are still required to corroborate these findings. This study provides an up-to-date overview and a thematic summary of the current available evidence on the application of RFA and IRE on PDAC, together with a comparison of the two procedures. PMID:26981115

  1. Local Ablative Strategies for Ductal Pancreatic Cancer (Radiofrequency Ablation, Irreversible Electroporation: A Review

    Directory of Open Access Journals (Sweden)

    Salvatore Paiella

    2016-01-01

    Full Text Available Pancreatic ductal adenocarcinoma (PDAC has still a dismal prognosis. Locally advanced pancreatic cancer (LAPC accounts for the 40% of the new diagnoses. Current treatment options are based on chemo- and radiotherapy regimens. Local ablative techniques seem to be the future therapeutic option for stage-III patients with PDAC. Radiofrequency Ablation (RFA and Irreversible Electroporation (IRE are actually the most emerging local ablative techniques used on LAPC. Initial clinical studies on the use of these techniques have already demonstrated encouraging results in terms of safety and feasibility. Unfortunately, few studies on their efficacy are currently available. Even though some reports on the overall survival are encouraging, randomized studies are still required to corroborate these findings. This study provides an up-to-date overview and a thematic summary of the current available evidence on the application of RFA and IRE on PDAC, together with a comparison of the two procedures.

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

    International Nuclear Information System (INIS)

    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 192Ir and 60Co 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 192Ir and 60Co will reduce the lead thickness by a factor of five for 192Ir and ten for 60Co. 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)

  3. Cross-species translation of the Morris maze for Alzheimer's disease.

    Science.gov (United States)

    Possin, Katherine L; Sanchez, Pascal E; Anderson-Bergman, Clifford; Fernandez, Roland; Kerchner, Geoffrey A; Johnson, Erica T; Davis, Allyson; Lo, Iris; Bott, Nicholas T; Kiely, Thomas; Fenesy, Michelle C; Miller, Bruce L; Kramer, Joel H; Finkbeiner, Steven

    2016-02-01

    Analogous behavioral assays are needed across animal models and human patients to improve translational research. Here, we examined the extent to which performance in the Morris water maze - the most frequently used behavioral assay of spatial learning and memory in rodents - translates to humans. We designed a virtual version of the assay for human subjects that includes the visible-target training, hidden-target learning, and probe trials that are typically administered in the mouse version. We compared transgenic mice that express human amyloid precursor protein (hAPP) and patients with mild cognitive impairment due to Alzheimer's disease (MCI-AD) to evaluate the sensitivity of performance measures in detecting deficits. Patients performed normally during visible-target training, while hAPP mice showed procedural learning deficits. In hidden-target learning and probe trials, hAPP mice and MCI-AD patients showed similar deficits in learning and remembering the target location. In addition, we have provided recommendations for selecting performance measures and sample sizes to make these assays sensitive to learning and memory deficits in humans with MCI-AD and in mouse models. Together, our results demonstrate that with careful study design and analysis, the Morris maze is a sensitive assay for detecting AD-relevant impairments across species.

  4. 7-NI and ODQ Disturbs Memory in the Elevated Plus Maze, Morris Water Maze, and Radial Arm Maze Tests in Mice.

    Science.gov (United States)

    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.

  5. Optical-vortex laser ablation

    OpenAIRE

    Hamazaki, Junichi; Morita, Ryuji; Chujo, Keisuke; Kobayashi, Yusuke; Tanda, Satoshi; Omatsu, Takashige

    2010-01-01

    Laser ablation of Ta plates using nanosecond optical vortex pulses was carried out, for the first time. It was suggested that owing to orbital angular momentum of optical vortex, clearer and smoother processed surfaces were obtained with less ablation threshold fluence, in comparison with the ablation by a nonvortex annular beam modified from a spatially Gaussian beam.

  6. Slab model for Rayleigh--Taylor stabilization by vortex shedding, compressibility, thermal conduction, and ablation

    International Nuclear Information System (INIS)

    Analytical models are derived for stabilization of the Rayleigh--Taylor instability of an ablatively accelerated slab. The procedure is to conserve mass, momentum, and energy flux across a perturbed interface through which plasma flows. In various regimes, the stabilization mechanism can be described as vortex shedding, compressibility, thermal conduction, and ablation. Comparisons are made with recent fluid simulations, and simple laws relevant to laser-driven ablative acceleration are derived

  7. Evidence for social cooperation in rodents by automated maze

    OpenAIRE

    Avi Avital; Shlomit Aga-Mizrachi; Salman Zubedat

    2016-01-01

    Social cooperation is defined as a joint action for mutual benefit that depends on the individual and the counterparts’ behaviors. To gain valid evidence for social cooperation behavior we conducted a series of experiments in our suggested fully automated non-conditioned maze and depicted three major findings: (i) During 18 days of training the rats showed a progressive social learning curve as well as latent social learning; (ii) Examining the perceptual communication between the cooperating...

  8. 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.)

  9. Actual role of radiofrequency ablation of liver metastases

    International Nuclear Information System (INIS)

    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.)

  10. Tumor ablations in IMRI

    Institute of Scientific and Technical Information of China (English)

    Roberto Blanco Sequeiros

    2002-01-01

    @@ IntroductionMagnetic resonance imaging based guidance control and monitoring of minimally invasive intervention has developed from a hypothetical concept to a practical possibility. Magnetic-resonance-guided interstitial therapy in principle is defined as a treatment technique for ablating deepseated tumors in the human body.

  11. Spark ablation device

    NARCIS (Netherlands)

    Schmidt-Ott, A.; Pfeiffer, T.V.

    2013-01-01

    A spark ablation device for generating nanoparticles comprising a spark generator; the spark generator comprising first and second electrodes, wherein the spark generator further comprises at least one power source which is arranged to be operative at a first energy level for maintaining a discharge

  12. Optimal Navigation of Self-Propelled Colloids in Microstructured Mazes

    Science.gov (United States)

    Yang, Yuguang; Bevan, Michael

    Controlling navigation of self-propelled microscopic `robots' subject to random Brownian motion in complex microstructured environments (e.g., porous media, tumor vasculature) is important to many emerging applications (e.g., enhanced oil recovery, drug delivery). In this work, we design an optimal feedback policy to navigate an active self-propelled colloidal rod in complex mazes with various obstacle types. Actuation of the rods is modelled based on a light-controlled osmotic flow mechanism, which produces different propulsion velocities along the rod's long axis. Actuator-parameterized Langevin equations, with soft rod-obstacle repulsive interactions, are developed to describe the system dynamics. A Markov decision process (MDP) framework is used for optimal policy calculations with design goals of colloidal rods reaching target end points in minimum time. Simulations show that optimal MDP-based policies are able to control rod trajectories to reach target regions order-of-magnitudes faster than uncontrolled rods, which diverges as maze complexity increases. An efficient multi-graph based implementation for MDP is also presented, which scales linearly with the maze dimension.

  13. Evidence for social cooperation in rodents by automated maze.

    Science.gov (United States)

    Avital, Avi; Aga-Mizrachi, Shlomit; Zubedat, Salman

    2016-01-01

    Social cooperation is defined as a joint action for mutual benefit that depends on the individual and the counterparts' behaviors. To gain valid evidence for social cooperation behavior we conducted a series of experiments in our suggested fully automated non-conditioned maze and depicted three major findings: (i) During 18 days of training the rats showed a progressive social learning curve as well as latent social learning; (ii) Examining the perceptual communication between the cooperating partners, we found a correlation between the available perceptual modalities and the social cooperation performance; and (iii) Investigating contextual learning as a competing process to the social cooperation, we found that additional contextual cues impaired the social cooperation performance. In conclusion, our suggested automated cooperation maze is designed to further our understanding of social cooperation under normal conditions, such as decision-making, and to examine the neural basis of social cooperation. A variety of neuropsychiatric disorders are characterized by disruptions in social behavior and social cognition, including depression, autism spectrum disorders, obsessive-compulsive disorder, and schizophrenia. Thus, on the pathological end, our maze for social cooperation evaluation can contribute significantly to the investigation of a wide range of social cooperation impairments in a rodent model. PMID:27378418

  14. 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.

  15. Radiofrequency ablation for neuroendocrine liver metastases: a systematic review.

    Science.gov (United States)

    Mohan, Helen; Nicholson, Patrick; Winter, Des C; O'Shea, Donal; O'Toole, Dermot; Geoghegan, Justin; Maguire, Donal; Hoti, Emir; Traynor, Oscar; Cantwell, Colin P

    2015-07-01

    To determine the efficacy of radiofrequency (RF) ablation in neuroendocrine tumor (NET) liver metastases. A systematic review was performed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Eight studies were included (N = 301). Twenty-six percent of RF ablation procedures were percutaneous (n = 156), with the remainder conducted at surgery. Forty-eight percent of patients had a concomitant liver resection. Fifty-four percent of patients presented with symptoms, with 92% reporting symptom improvement following RF ablation (alone or in combination with surgery). The median duration of symptom improvement was 14-27 months. However, recurrence was common (63%-87%). RF ablation can provide symptomatic relief in NET liver metastases alone or in combination with surgery. PMID:25840836

  16. Laser ablation in analytical chemistry-a review.

    Science.gov (United States)

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

    2002-05-24

    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. PMID:18968642

  17. 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.

  18. Percutaneous radiofrequency ablation for benign nodules of the thyroid gland

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Jung Hwan; Jeong, Hyun Jo; Kim, Yoon Suk; Kwak, Min Sook; Chang, Sun Hee [Daerim St. Mary' s Hospital, Seoul (Korea, Republic of); Rhim, Hyun Chul [Hanyang University Hospital, Seoul (Korea, Republic of)

    2005-07-15

    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.

  19. When to go epicardially during ventricular tachycardia ablation? Role of surface electrocardiogram

    OpenAIRE

    Ozcan, Emin Evren; Széplaki, Gábor; Tahin, Tamás; Osztheimer, István; SZILÁGYI Szabolcs; Merkely, Béla; Gellér, László

    2013-01-01

    Early recognition of ventricular tachycardias (VTs) with epicardial circuits is crucial. Surface electrocardiogram (ECG) suggesting an epicardial origin could guide ablation procedures and increase success rates. A 35-year-old female patient with VT treated by combined epicardial and endocardial ablation approach is presented in this report, and the role of surface electrocardiogram and timing of epicardial access is discussed.

  20. CT thermometry for cone-beam CT guided ablation

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Dunne, Ruth M., E-mail: rmdunne@partners.org [Division of Abdominal Imaging and Intervention, Department of Radiology, Brigham and Women' s Hospital, 75 Francis Street, Boston, MA 02115 (United States); Shyn, Paul B., E-mail: pshyn@partners.org [Division of Abdominal Imaging and Intervention, Department of Radiology, Brigham and Women' s Hospital, 75 Francis Street, Boston, MA 02115 (United States); Sung, Jeffrey C., E-mail: jcsung@gmail.com [Division of Abdominal Imaging and Intervention, Department of Radiology, Brigham and Women' s Hospital, 75 Francis Street, Boston, MA 02115 (United States); Tatli, Servet, E-mail: statli@partners.org [Division of Abdominal Imaging and Intervention, Department of Radiology, Brigham and Women' s Hospital, 75 Francis Street, Boston, MA 02115 (United States); Morrison, Paul R. [Division of Abdominal Imaging and Intervention, Department of Radiology, Brigham and Women' s Hospital, 75 Francis Street, Boston, MA 02115 (United States); Catalano, Paul J., E-mail: pcata@jimmy.harvard.edu [Department of Biostatistics and Computational Biology, Dana Farber Cancer Institute, 450 Brookline Avenue, CLSB 11007, Boston, MA 02215 (United States); Department of Biostatistics, Harvard School of Public Health, Boston, MA 02215 (United States); Silverman, Stuart G., E-mail: sgsilverman@partners.org [Division of Abdominal Imaging and Intervention, Department of Radiology, Brigham and Women' s Hospital, 75 Francis Street, Boston, MA 02115 (United States)

    2014-04-15

    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.

  2. Lesion size in relation to ablation site during radiofrequency ablation

    DEFF Research Database (Denmark)

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

    1998-01-01

    convective cooling by induction of a flow around the electrode tip increases lesion dimensions and power consumptions. Furthermore we conclude that for the given target temperature the power consumption is positively correlated with lesion volume (p ...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...... larger for septal applications than apical applications (p convective cooling by induction of flow yielded larger lesion volume, depth and width (p

  3. Unconscious sedation/analgesia with propofol versus conscious sedation with fentanyl/midazolam for catheter ablation of atrial fibrillation: a prospective, randomized study

    Institute of Scientific and Technical Information of China (English)

    TANG Ri-bo; MA Chang-sheng; DONG Jian-zeng; ZHAO Wen-du; LIU Xing-peng; KANG Jun-ping; LONG De-yong; YU Rong-hui; HU Fu-li; LIU Xiao-hui

    2007-01-01

    @@ Catheter ablation of atrial fibrillation (AF) has been increased dramatically recently.1 However, it is an unpleasant procedure with intolerable pain without sedation. Propofol and fentanyl/midazolam have been widely used in painful clinical examination and cardiovascular procedures with established safety and efficacy.2,3 Propofol, alfentanyl and midazolam were administrated for catheter ablation in some electrophysiological labs for a less painful procedure.4However, there is few published work on the sedation regimen for catheter ablation of AF.

  4. Cows in the Maze And other mathematical explorations

    CERN Document Server

    Stewart, Ian

    2010-01-01

    From the mathematics of mazes, to cones with a twist, and the amazing sphericon - and how to make one - Ian Stewart is back with more mathematical stories and puzzles that are as quirky as they are fascinating, and each from the cutting edge of the world of mathematics. We find out about the mathematics of time travel, explore the shape of teardrops (which are not tear-drop shaped, but something much, much more strange!), dance with dodecahedra, and play the game of Hex, amongst many more strange and delightful mathematical diversions.

  5. 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.

  6. 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.

  7. AF Termination: the Holy Grail of Persistent AF Ablation?

    Directory of Open Access Journals (Sweden)

    Dennis H. Lau

    2010-05-01

    Full Text Available The optimal catheter ablation approach for long-standing persistent atrial fibrillation (AF remains elusive despite significant advances made in our understanding of this arrhythmia. A recent systematic review highlighted the significant variation in procedural success rate both within and between techniques, necessitating repeat ablation procedures and anti-arrhythmic drugs to achieve improved outcomes in those with long-standing persistent AF . Indeed, current expert consensus statement recommended ablation beyond ostial pulmonary vein isolation for these patients . Despite incorporating various substrate modification techniques which commonly include linear lesions and targeting of complex fractionated electrograms, the reported success rates from various laboratories are still below par to those in paroxysmal AF patients.

  8. Prediction of Primary Slow-Pathway Ablation Success Rate According to the Characteristics of Junctional Rhythm Developed during the Radiofrequency Catheter Ablation of Atrioventricular Nodal Reentrant Tachycardia

    Directory of Open Access Journals (Sweden)

    Maryam Moshkani Farahani

    2011-02-01

    Full Text Available Background: Nowadays, developed junctional rhythm (JR that occurs during slow-pathway radiofrequency (RF catheter ablation of atrioventricular nodal reentrant tachycardia (AVNRT has been focused upon as a highly sensitive surrogate end point for successful radiofrequency ablation. This study was conducted to assess the relationship between the presence and pattern of developed JR during the RF ablation of AVNRT and a successful outcome.Methods: Seventy-five patients aged between 14 and 88 who underwent slow-pathway RF ablation due to symptomatic AVNRT were enrolled into the study and received a total of 162 RF energy applications. Combined anatomic and electrogram mapping approach was used for slow-pathway RF ablation. The ablation procedure consisted of 60-second, 60 °C temperature-controlled energy delivery. After each ablation pulse, successful ablation was assessed according to the loss of AVNRT inducibility via isoproterenol infusion. Four different patterns were considered for the developed JR, namely sparse, intermittent, continuous, and transient block. Success ablation rate was assessed with respect to the position, pattern, and number of junctional beats.Results: Successful RF ablation with a loss of AVNRT inducibility was achieved in 43 (57.3% patients using 119 RF energy applications (73.5%. JR developed in 133 of the 162 (82.1% applications with a given sensitivity of 90.8% and low specificity of 41.9% as an end point of successful RF ablation, with a negative predictive value of 62.1%. The mean number of the developed junctional beats was significantly higher in the successful ablations (p value < 0.001, and the ROC analysis revealed that the best cut-off point of the cumulative junctional beats for identifying accurate AVNRT ablation therapy is 14 beats with 90.76 % sensitivity and 90.70% specificity. There were no significant differences in terms of successful ablation rates according to the four different patterns of JR and its

  9. 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.

  10. Efficacy of percutaneous radiofrequency ablation of osteoid osteoma in children

    Energy Technology Data Exchange (ETDEWEB)

    Donkol, Ragab H. [Cairo University, Department of Radiology, Faculty of Medicine, Cairo (Egypt); Assir Central Hospital, Department of Radiology, P.O. Box 34, Abha (Saudi Arabia); Al-Nammi, Ahmed [Assir Central Hospital, Department of Radiology, P.O. Box 34, Abha (Saudi Arabia); Moghazi, Khaled [Alexandria University, Faculty of Medicine, Alexandria (Egypt)

    2008-02-15

    Percutaneous radiofrequency (RF) ablation of osteoid osteoma has high technical and clinical success rates. However, there are limited data on its use in the treatment of osteoid osteoma in children. To assess the safety and efficacy of CT-guided percutaneous RF ablation of osteoid osteoma in children and compare the outcomes with published data on its use in patients unselected for age. From January 2003 to July 2006, 23 children with osteoid osteoma were treated with CT-guided RF ablation using a straight rigid electrode. Their mean age was 11 years (range 3.5-16 years) and there were 15 boys and 8 girls. The procedures were carried out under general anaesthesia. Follow-up was performed to assess technical and clinical outcome. The mean follow-up period was 2.5 years (range 13-49 months). Technical success was achieved in 21 children (91.3%). Failure occurred in two children, in one due to failure to adequately localize the nidus within the dense sclerosis and in the other because of a short ablation time (2 min) because he developed hyperthermia. Clinical success was achieved in 18 patients within 2-5 days (primary clinical success rate 78.2%).These patients were allowed to fully weight-bear and function without limitation 1 week after the procedure. Pain recurrence was observed in two patients; one was treated successfully with a second ablation after 6 months (secondary clinical success rate 82.6%). Hyperthermia was observed in two patients during the procedure. Three other minor complications were observed: wound infection in one child and skin burn in two children. No major immediate or delayed complications were observed. Percutaneous CT-guided RF ablation is an effective and safe minimally invasive procedure for the treatment of osteoid osteoma in children. It has high technical and clinical success rates that are slightly lower than those of patients with a wider range of ages. (orig.)

  11. Endoscopic ultrasound guided radiofrequency ablation in pancreas

    DEFF Research Database (Denmark)

    Seicean, Andrada; Tefas, Cristian; Ungureanu, Bogdan;

    2014-01-01

    Radiofrequency ablation of the pancreas represents a more effective tumor-destruction method compared to other ablation techniques. The endoscopic ultrasound guided radiofrequency ablation is indicated for locally advanced, non-metastatic pancreatic adenocarcinoma, without the need of general...

  12. 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

  13. Image-guided radiofrequency ablation of hepatocellular carcinoma (HCC): Is MR guidance more effective than CT guidance?

    Energy Technology Data Exchange (ETDEWEB)

    Clasen, Stephan, E-mail: stephan.clasen@med.uni-tuebingen.de [University Hospital, Department of Diagnostic and Interventional Radiology, Hoppe-Seyler Str. 3, 72076 Tübingen (Germany); Rempp, Hansjörg, E-mail: hansjoerg.rempp@med.uni-tuebingen.de [University Hospital, Department of Diagnostic and Interventional Radiology, Hoppe-Seyler Str. 3, 72076 Tübingen (Germany); Hoffmann, Rüdiger, E-mail: ruediger.hoffmann@med.uni-tuebingen.de [University Hospital, Department of Diagnostic and Interventional Radiology, Hoppe-Seyler Str. 3, 72076 Tübingen (Germany); Graf, Hansjörg, E-mail: hansjoerg.graf@med.uni-tuebingen.de [University Hospital, Department of Diagnostic and Interventional Radiology, Section of Experimental Radiology, Hoppe-Seyler Str. 3, 72076 Tübingen (Germany); Pereira, Philippe L., E-mail: Philippe.Pereira@slk-kliniken.de [SLK Clinic Heilbronn, Clinic for Radiology, Minimal-invasive Therapies, and Nuclear Medicine, Am Gesundbrunnen 20-26, 74078 Heilbronn (Germany); Claussen, Claus D., E-mail: claus.claussen@med.uni-tuebingen.de [University Hospital, Department of Diagnostic and Interventional Radiology, Hoppe-Seyler Str. 3, 72076 Tübingen (Germany)

    2014-01-15

    Objectives: The purpose of the study was to retrospectively compare technique effectiveness of computed tomography (CT)-guided versus magnetic resonance (MR)-guided radiofrequency (RF) ablation of hepatocellular carcinoma (HCC). Materials and methods: In 35 consecutive patients 53 CT-guided (n = 29) or MR-guided (n = 24) ablation procedures were performed in the treatment of 56 (CT: 29; MR: 27) HCC. The entire ablation procedure was performed at a multislice CT-scanner or an interventional 0.2-Tesla MR-scanner. Assessment of treatment response was based on dynamic MR imaging at 1.5 Tesla. The mean follow-up was 22.9 months. Primary technique effectiveness was assessed 4 months after ablation therapy. Secondary technique effectiveness was assessed 4 months after a facultative second ablation procedure. Primary and secondary technique effectiveness of CT-guided and MR-guided RF ablation was compared by using Chi-Square (likelihood ratio) test. Results: Primary technique effectiveness after a single session was achieved in 26/27 (96.3%) HCC after MR-guided RF ablation and 23/29 (79.3%) HCC after CT-guided RF ablation (Chi-Square: p = 0.04). Secondary technique effectiveness was achieved in 26/27 (96.3%) HCC after MR-guided RF ablation and in 26/29 (89.7%) HCC after CT-guided RF ablation (Chi-Square: p = 0.32). A local tumor progression was detected in 8/52 (15.4%) tumors after initial technique effectiveness. Major complications were detected after 3/53 (5.7%) ablation procedures. Conclusions: CT-guided and MR-guided RF ablations are locally effective therapies in the treatment of HCC. Due to a higher rate of primary technique effectiveness MR-guided RF ablation may reduce the number of required sessions for complete tumor treatment.

  14. Radiofrequency Ablation for Chronic Low Back Pain: A Systematic Review of Randomized Controlled Trials

    Directory of Open Access Journals (Sweden)

    Laura E Leggett

    2014-01-01

    Full Text Available BACKGROUND: Radiofrequency ablation (RFA, a procedure using heat to interrupt pain signals in spinal nerves, is an emerging treatment option for chronic low back pain. Its clinical efficacy has not yet been established.

  15. Goal representation heuristic dynamic programming on maze navigation.

    Science.gov (United States)

    Ni, Zhen; He, Haibo; Wen, Jinyu; Xu, Xin

    2013-12-01

    Goal representation heuristic dynamic programming (GrHDP) is proposed in this paper to demonstrate online learning in the Markov decision process. In addition to the (external) reinforcement signal in literature, we develop an adaptively internal goal/reward representation for the agent with the proposed goal network. Specifically, we keep the actor-critic design in heuristic dynamic programming (HDP) and include a goal network to represent the internal goal signal, to further help the value function approximation. We evaluate our proposed GrHDP algorithm on two 2-D maze navigation problems, and later on one 3-D maze navigation problem. Compared to the traditional HDP approach, the learning performance of the agent is improved with our proposed GrHDP approach. In addition, we also include the learning performance with two other reinforcement learning algorithms, namely Sarsa(λ) and Q-learning, on the same benchmarks for comparison. Furthermore, in order to demonstrate the theoretical guarantee of our proposed method, we provide the characteristics analysis toward the convergence of weights in neural networks in our GrHDP approach. PMID:24805221

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

    International Nuclear Information System (INIS)

    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

  17. 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

  18. Catheter ablation of persistent atrial fibrillation in a patient with dextrocardia

    Institute of Scientific and Technical Information of China (English)

    XUE Zeng-ming; SANG Cai-hua; DONG Jian-zeng; MA Chang-sheng

    2012-01-01

    The technique of catheter ablation for atrial fibrillation (AF) has advanced rapidly over the last ten years.Catheter ablation of AF with special anatomy like dextrocardia was seldomly reported,1,2 which may be difficult for its complex anatomy.Three-dimensional electroanatomical mapping system and image integration system may be helpful during the procedure.We report a case with drug refractory persistent AF and dextrocardia,who underwent an ablation procedure.%Dextrocardia is a rare anomaly where the heart is located on the right side of the chest instead of the normal left side.Ablation of atrial fibrillation (AF) with such an inverted anatomy may be challenging for the manipulation of the catheters.Here we report a case of dextrocardia who underwent ablation for persistent AF guided by image integration system.

  19. Optimization of the generator settings for endobiliary radiofrequency ablation

    Institute of Scientific and Technical Information of China (English)

    Maximilien; Barret; Sarah; Leblanc; Ariane; Vienne; Alexandre; Rouquette; Frederic; Beuvon; Stanislas; Chaussade; Frederic; Prat

    2015-01-01

    AIM:To determine the optimal generator settings for endobiliary radiofrequency ablation. METHODS:Endobiliary radiofrequency ablation was performed in live swine on the ampulla of Vater,the common bile duct and in the hepatic parenchyma. Radiofrequency ablation time,"effect",and power were allowed to vary. The animals were sacrificed two hours after the procedure. Histopathological assessment of the depth of the thermal lesions was performed. RESULTS:Twenty-five radiofrequency bursts were applied in three swine. In the ampulla of Vater(n = 3),necrosis of the duodenal wall was observed starting with an effect set at 8,power output set at 10 W,and a 30 s shot duration,whereas superficial mucosal damage of up to 350 μm in depth was recorded for an effect set at 8,power output set at 6 W and a 30 s shot duration. In the common bile duct(n = 4),a 1070 μm,safe and efficient ablation was obtained for an effect set at 8,a power output of 8 W,and an ablation time of 30 s. Within the hepatic parenchyma(n = 18),the depth of tissue damage varied from 1620 μm(effect = 8,power = 10 W,ablation time = 15 s) to 4480 μm(effect = 8,power = 8 W,ablation time = 90 s). CONCLUSION:The duration of the catheter application appeared to be the most important parameter influencing the depth of the thermal injury during endobiliary radiofrequency ablation. In healthy swine,the currently recommended settings of the generator may induce severe,supratherapeutic tissue damage in the biliary tree,especially in the high-risk area of the ampulla of Vater.

  20. Osteoid Osteoma Treated with Radiofrequency Ablation

    Directory of Open Access Journals (Sweden)

    Murat Çakar

    2015-01-01

    Full Text Available Purpose. Our aim is to evaluate the results of treatment with computed tomography (CT guided percutaneous radiofrequency ablation for osteoid osteomas which were localized in a difficult area for operation. Materials and Methods. Glenoid, distal tibia, humerus shaft, proximal humerus, and in third finger of the hand proximal phalanx were involved in one patient. Proximal femur was involved in three patients, distal femur was involved in three patients, and proximal tibia was involved in two patients. 9 males and 4 females were aged 4 to 34 years (mean age: 18.5 years. All patients had pain and were evaluated with X-rays, CT, bone scintigraphy, and MRI. In all patients, RF ablation was performed with local anesthesia. The lesion heated to 90°C for 6 minutes. Results. All of the patients achieved complete pain relief after ablation and were fully weight bearing without any support. In all patients, there was soft tissue edema after the procedure. During follow-up, all patients were free from the pain and there was no sign about the tumor. There was no other complication after the process. Conclusion. CT guided RFA is a minimally invasive, safe, and cost-effective treatment for osteoid osteoma placed in difficult area for surgery.

  1. 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...

  2. 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.

  3. 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.

  4. Percutaneous laser ablation of unresectable primary and metastatic adrenocortical carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    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.

  5. Sex-Specific Effects of Gonadectomy and Hormone Treatment on Acquisition of a 12-Arm Radial Maze Task by Sprague Dawley Rats

    OpenAIRE

    Gibbs, Robert B; Johnson, David A.

    2008-01-01

    The effects of gonadectomy and hormone treatment on spatial learning were evaluated in adult male and female rats using a modified version of a 12-arm radial maze task. In this version, procedures were used to minimize the effectiveness of strategies less reliant on working and reference memory. Results demonstrate significant sex differences favoring male performance on the working memory component of the task. In contrast, females performed slightly better than males on the reference memory...

  6. Pulmonary vein triggers, focal sources, rotors and atrial cardiomyopathy: implications for the choice of the most effective ablation therapy.

    Science.gov (United States)

    Pison, L; Tilz, R; Jalife, J; Haïssaguerre, M

    2016-05-01

    Understanding of the pathophysiological mechanism(s) underlying atrial fibrillation (AF) is the foundation on which current ablation strategies are built. In the vast majority of patients with paroxysmal AF, the ablation procedure should target the pulmonary veins. In patients with nonparoxysmal AF, however, pulmonary vein isolation alone seems to be insufficient to prevent the arrhythmia. Several recent clinical trials have investigated the concept that rotors (re-entry based on a meandering central core from which spiral waves emanate) might be the mechanism responsible for sustaining AF. Ablation of these localized AF sources is an important step towards substrate-driven procedures in persistent AF. Hybrid AF ablation procedures, based on the integration of endocardial transcatheter and epicardial off-pump surgical techniques, have been introduced to overcome their mutual shortcomings. The long-term results are encouraging, especially in currently challenging settings such as nonparoxysmal AF and failed endocardial catheter ablation procedures. PMID:26991806

  7. 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.

  8. Topography-guided custom ablation treatment for treatment of keratoconus.

    Science.gov (United States)

    Shetty, Rohit; D'Souza, Sharon; Srivastava, Samaresh; Ashwini, R

    2013-08-01

    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. PMID:23925335

  9. Cerebral embolization during AF ablation �Pathophysiology, Prevention and Management

    Directory of Open Access Journals (Sweden)

    Nasir Shariff, MD

    2013-04-01

    Full Text Available Catheter based ablation therapy has evolved as an invaluable tool in the management of symptomatic patients with atrial fibrillation (AF. The procedure of AF ablation requires instrumentation in the systemic circulation predisposing to various concerns that can result in systemic embolization. We will describe the reported incidence of these events and refer to the various pathophysiologic explanations for their occurrence. Details on the risk factors and the relevant studies will also be reviewed. Preventive and treatment strategies in patients undergoing the ablation procedure will be discussed.

  10. Thermal ablation for the treatment of abdominal tumors.

    Science.gov (United States)

    Brace, Christopher L; Hinshaw, J Louis; Lubner, Meghan G

    2011-03-07

    Percutaneous thermal ablation is an emerging treatment option for many tumors of the abdomen not amenable to conventional treatments. During a thermal ablation procedure, a thin applicator is guided into the target tumor under imaging guidance. Energy is then applied to the tissue until temperatures rise to cytotoxic levels (50-60 °C). Various energy sources are available to heat biological tissues, including radiofrequency (RF) electrical current, microwaves, laser light and ultrasonic waves. Of these, RF and microwave ablation are most commonly used worldwide. During RF ablation, alternating electrical current (~500 kHz) produces resistive heating around the interstitial electrode. Skin surface electrodes (ground pads) are used to complete the electrical circuit. RF ablation has been in use for nearly 20 years, with good results for local tumor control, extended survival and low complication rates. Recent studies suggest RF ablation may be a first-line treatment option for small hepatocellular carcinoma and renal-cell carcinoma. However, RF heating is hampered by local blood flow and high electrical impedance tissues (eg, lung, bone, desiccated or charred tissue). Microwaves may alleviate some of these problems by producing faster, volumetric heating. To create larger or conformal ablations, multiple microwave antennas can be used simultaneously while RF electrodes require sequential operation, which limits their efficiency. Early experiences with microwave systems suggest efficacy and safety similar to, or better than RF devices. Alternatively, cryoablation freezes the target tissues to lethal levels (-20 to -40 °C). Percutaneous cryoablation has been shown to be effective against RCC and many metastatic tumors, particularly colorectal cancer, in the liver. Cryoablation may also be associated with less post-procedure pain and faster recovery for some indications. Cryoablation is often contraindicated for primary liver cancer due to underlying coagulopathy and

  11. LASER ABLATION STUDIES OF CONCRETE

    Science.gov (United States)

    Laser ablation was studied as a means of removing radioactive contaminants from the surface and near-surface regions of concrete. We present the results of ablation tests on cement and concrete samples using a 1.6 kW pulsed Nd:YAG laser with fiber optic beam delivery. The laser-s...

  12. Radiofrequency ablation of osteoid osteoma

    NARCIS (Netherlands)

    Vanderschueren, Geert Maria Joris Michael

    2009-01-01

    The main purpose of this thesis was to evaluate the effectiveness and safety of CT-guided radiofrequency ablation for the treatment of spinal and non-spinal osteoid osteomas. Furthermore, the technical requirements needed for safe radiofrequency ablation and the clinical outcome after radiofrequency

  13. Radiofrequency ablation of locally advanced pancreatic adenocarcinoma:An overview

    Institute of Scientific and Technical Information of China (English)

    Mirko; D’Onofrio; Emilio; Barbi; Roberto; Girelli; Enrico; Martone; Anna; Gallotti; Roberto; Salvia; Paolo; Tinazzi; Martini; Claudio; Bassi; Paolo; Pederzoli; Roberto; Pozzi; Mucelli

    2010-01-01

    Radiofrequency ablation(RFA)of pancreatic neoplasms is restricted to locally advanced,non-resectable but nonmetastatic tumors.RFA of pancreatic tumors is nowadays an ultrasound-guided procedure performed during laparotomy in open surgery.Intraoperative ultrasound covers the mandatory role of staging,evaluation of feasibility,guidance and monitoring of the procedure.Different types of needle can be used.The first aim in the evaluation of RFA as a treatment for locally advanced pancreatic ductal adenocarcinom...

  14. The water maze paradigm in experimental studies of chronic cognitive disorders: Theory, protocols, analysis, and inference.

    Science.gov (United States)

    Kapadia, Minesh; Xu, Josie; Sakic, Boris

    2016-09-01

    An instrumental step in assessing the validity of animal models of chronic cognitive disorders is to document disease-related deficits in learning/memory capacity. The water maze (WM) is a popular paradigm because of its low cost, relatively simple protocol and short procedure time. Despite being broadly accepted as a spatial learning task, inference of generalized, bona fide "cognitive" dysfunction can be challenging because task accomplishment is also reliant on non-cognitive processes. We review theoretical background, testing procedures, confounding factors, as well as approaches to data analysis and interpretation. We also describe an extended protocol that has proven useful in detecting early performance deficits in murine models of neuropsychiatric lupus and Alzheimer's disease. Lastly, we highlight the need for standardization of inferential criteria on "cognitive" dysfunction in experimental rodents and exclusion of preparations of a limited scientific merit. A deeper appreciation for the multifactorial nature of performance in WM may also help to reveal other deficits that herald the onset of neurodegenerative brain disorders. PMID:27229758

  15. 达比加群酯在房性快速心律失常射频导管消融围术期抗凝治疗中的应用%Safety and efficacy of dabigatran for the peri-procedural anticoagulation in patients undergoing abla-tion of atrial tachyarrhythmias

    Institute of Scientific and Technical Information of China (English)

    周高俊; 郭艳如; 曹克将; 陈明龙; 杨兵; 郦明芳; 张凤祥; 居维竹; 陈红武; 杨刚; 顾凯; 谢欣

    2016-01-01

    Objective To evaluate the safety and efficacy of dabigatran for the peri-procedural antico-agulation in patients with atrial tachyarrhythmias ( ATA) undergoing radiofrequency catheter ablation ( RFCA) . Methods From September 2013 to April 2015,859 patients who underwent RFCA of ATA in the First Affilia-ted Hospital of Nanjing Medical University were retrospectively reviewed. Among them,165 patients administra-ted with dabigatran were defined as Dabigatran group,and another 165 patients taking warfarin matched with age (±3years),sex,type of ATA,and comorbidities were defined as Warfarin group. We evaluated detailed peri-procedural anticoagulation regimens, and compared the incidence of thromboembolic events, major and minor bleeding events and other adverse effects of drugs between these two groups. Results Compared to Warfarin group,Dabigatran group had significantly lower level of the baseline activated clotting time (ACT)[(143. 6± 24. 9)s vs(197. 8±59. 9)s,P0. 05) . The in-cidence of gastrointestinal adverse events was significantly higher in Dabigatran group compared with Warfarin group (9. 1% vs. 0,P0.05)。达比加群酯组胃肠道反应发生率高于华法林组(9.1%对0,P<0.001)。结论达比加群酯可安全有效地用于ATA患者RFCA围术期的抗凝,术中应加强ACT监测。

  16. Cognitive Evaluation Using Morris Water Maze in Neurotrauma.

    Science.gov (United States)

    Deng-Bryant, Ying; Leung, Lai Yee; Caudle, Krista; Tortella, Frank; Shear, Deborah

    2016-01-01

    The Morris water maze (MWM) task is one of the most widely used and versatile tools in behavioral neuroscience for evaluating spatial learning and memory. With regard to detecting cognitive deficits following central nervous system (CNS) injuries, MWM has been commonly utilized in various animal models of neurotrauma, such as fluid percussion injury (FPI), cortical controlled impact (CCI) injury, weight-drop impact injury, and penetrating ballistic-like brain injury (PBBI). More importantly, it serves as a therapeutic index for assessing the efficacy of treatment interventions on cognitive performance following neurotrauma. Thus, it is critical to design an MWM testing paradigm that is sensitive yet discriminating for the purpose of evaluating potential therapeutic interventions. In this chapter, we discuss how multiple test manipulations, including the size of platform, numbers of trials per day, the frequency of retesting intervals, and the texture of platform surface, impact MWM's ability to detect cognitive deficits using a rat model of PBBI. PMID:27604737

  17. Changes in brain oxidative metabolism induced by water maze training.

    Science.gov (United States)

    Conejo, N M; González-Pardo, H; Vallejo, G; Arias, J L

    2007-03-16

    Although the hippocampus has been shown to be essential for spatial memory, the contribution of associated brain regions is not well established. Wistar rats were trained to find a hidden escape platform in the water maze during eight days. Following training, the oxidative metabolism in different brain regions was evaluated using cytochrome oxidase histochemistry. Metabolic activations were found in the prelimbic cortex, cornu ammonis (CA) 1 subfield of the dorsal hippocampus and the anterior thalamic nuclei, relative to yoked swim controls and naïve rats. In addition, many cross-correlations in brain metabolism were observed among the latter regions. These results support the implication of a hippocampal-prefrontal-thalamic system to spatial memory in rats. PMID:17222984

  18. Comparison of the Outcomes of Monopolar and Bipolar Radiofrequency Ablation in Surgical Treatment of Atrial Fibrillation

    Institute of Scientific and Technical Information of China (English)

    Wei-zhao Huang; Ying-meng Wu; Hong-yu Ye; Hai-ming Jiang

    2014-01-01

    Objective To compare the therapeutic effects and safety of monopolar and bipolar radiofrequency (RF) ablation used during cardiac surgery to treat atrial fibrillation. Methods We retrospectively studied a total of 81 patients with chronic atrial fibrillation who underwent open cardiac surgery with concomitant RF ablation between January 2007 and March 2011. Fifty-eight patients received bipolar RF ablation and 23 received monopolar RF ablation, respectively. The sinus rhythm restoration rate, the procedural duration, the frequency of severe perioperative complications, and mortality were compared between the two groups. Results The sinus rhythm restoration rate did not differ significantly between the two groups after follow-up of 15.1 ± 12.6 months (P=0.199). The frequencies of severe perioperative complications and mortality were also similar in the two groups. The total procedural time using bipolar RF ablation was significantly shorter than that using monopolar ablation (19.7±4.6 minutes vs. 28.1±8.5 minutes, P Conclusions Both monopolar and bipolar RF ablation are safe and effective in treating chronic atrial fibrillation patients during open cardiac surgery, but bipolar RF ablation is more convenient in practice.

  19. 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

  20. Water maze learning and hippocampal synaptic plasticity in streptozotocin diabetic rats: effects of insulin treatment

    NARCIS (Netherlands)

    Gispen, W.H.; Biessels, G.J.; Kamal, A.; Urban, I.J.A.; Spruijt, B.M.; Erkelens, D.W.

    1998-01-01

    Streptozotocin-diabetic rats express deficits in water maze learning and hippocampal synaptic plasticity. The present study examined whether these deficits could be prevented and/or reversed with insulin treatment. In addition, the water maze learning deficit in diabetic rats was further characteriz

  1. Effects of amphetamine and beta-endorphin fragments on maze performance in rats

    NARCIS (Netherlands)

    Bohus, B; de Boer, S.F.

    1990-01-01

    Fragments of beta-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 beta-endorphin fragments [beta-endorphin (beta E)-(2-9) and beta E-(2-16)] on maze behavior in more detail. In Experiment

  2. Mini-maze suffices as adjunct to mitral valve surgery in patients with preoperative atrial fibrillation

    NARCIS (Netherlands)

    Tuinenburg, AE; Van Gelder, IC; Tieleman, RG; Grandjean, JG; Huet, RCG; Van der Maaten, JMAA; Pieper, EG; De Kam, PJ; Ebels, MSCT; Crijns, HJGM

    2000-01-01

    Mini-Maze and Mitral Valve Surgery. Introduction: After mitral valve (MV) surgery, preoperative atrial fibrillation (AF) often recurs while cardioversion therapy generally fails. Additional Cox maze surgery improves postoperative arrhythmia outcome, but the extensive nature of such an approach limit

  3. A Seven-year Experience for The Surgical Radiofrequency Ablation in Patients With Atrial Fibrillation

    Institute of Scientific and Technical Information of China (English)

    Bin XIE; Hui-ming GUO; Ruo-bin WU; Cong LU

    2009-01-01

    Objective A 7-year experience for the treatment strategy using mono- and bi-polar radiofrequency (RF) ablation procedures in a heterogeneous group of patients was reported. Methods Between July 2003 and May 2009, the data of 314 consecutive patients aged 13 -75 (48. 70 + 11.09)undergone the radiofrequency ablation procedure for atrial fibrillation (AF) associated with concomitant cardiac surgery were analyzed. Monopolar was used for 91 patients; Medtronic bi-polar RF ablation procedure for 92 patients and Atricure RF ablation procedure for 131 patients. All patients were combined with valve surgery. Regular follow-ups were performed at 3, 6 month after surgery. Results Hospital mortality after combined open heart and surgical RF ablation was 0 %. The success rates for sinus rhythm con-version with monopolar RF were 73.6 % immediately, 74. 7 % at 3 months, 79. 1% at 6 months; with Medtronic bi-polar RF, the rates were 78.3 % immediately, 82. 8 % at 3 months, 84 % at 6 months; with Atricure bi-polar RF, the rates were 82. 4 % immediately, 84. 1% at 3 months, 83.9 % at 6 months. Conclusions The use of RF ablation pro-cedures is a safe and efficient option to cure AF during open heart surgery in a selective group of patients.

  4. Irrigated Tip Catheters for Radiofrequency Ablation in Ventricular Tachycardia

    Directory of Open Access Journals (Sweden)

    Andreas Müssigbrodt

    2015-01-01

    Full Text Available Radiofrequency (RF ablation with irrigated tip catheters decreases the likelihood of thrombus and char formation and enables the creation of larger lesions. Due to the potential dramatic consequences, the prevention of thromboembolic events is of particular importance for left-sided procedures. Although acute success rates of ventricular tachycardia (VT ablation are satisfactory, recurrence rate is high. Apart from the progress of the underlying disease, reconduction and the lack of effective transmural lesions play a major role for VT recurrences. This paper reviews principles of lesion formation with radiofrequency and the effect of tip irrigation as well as recent advances in new technology. Potential areas of further development of catheter technology might be the improvement of mapping by better substrate definition and resolution, the introduction of bipolar and multipolar ablation techniques into clinical routine, and the use of alternative sources of energy.

  5. An automated maze task for assessing hippocampus-sensitive memory in mice.

    Science.gov (United States)

    Pioli, Elsa Y; Gaskill, Brianna N; Gilmour, Gary; Tricklebank, Mark D; Dix, Sophie L; Bannerman, David; Garner, Joseph P

    2014-03-15

    Memory deficits associated with hippocampal dysfunction are a key feature of a number of neurodegenerative and psychiatric disorders. The discrete-trial rewarded alternation T-maze task is highly sensitive to hippocampal dysfunction. Normal mice have spontaneously high levels of alternation, whereas hippocampal-lesioned mice are dramatically impaired. However, this is a hand-run task and handling has been shown to impact crucially on behavioural responses, as well as being labour-intensive and therefore unsuitable for high-throughput studies. To overcome this, a fully automated maze was designed. The maze was attached to the mouse's home cage and the subject earned all of its food by running through the maze. In this study the hippocampal dependence of rewarded alternation in the automated maze was assessed. Bilateral hippocampal-lesioned mice were assessed in the standard, hand-run, discrete-trial rewarded alternation paradigm and in the automated paradigm, according to a cross-over design. A similarly robust lesion effect on alternation performance was found in both mazes, confirming the sensitivity of the automated maze to hippocampal lesions. Moreover, the performance of the animals in the automated maze was not affected by their handling history whereas performance in the hand-run maze was affected by prior testing history. By having more stable performance and by decreasing human contact the automated maze may offer opportunities to reduce extraneous experimental variation and therefore increase the reproducibility within and/or between laboratories. Furthermore, automation potentially allows for greater experimental throughput and hence suitability for use in assessment of cognitive function in drug discovery.

  6. Initial experience with circumferential pulmonary vein ablation guided by fusion of magnetic resonance imaging with three-dimensional electroanatomic mapping

    Institute of Scientific and Technical Information of China (English)

    TANG Kai; MA Jian; MA Fu-sheng; JlA Yu-he; ZHANG Shu

    2006-01-01

    @@ Catheter ablation for the treatment of atrial fibrillation (AF) has been a focal target of electrophysiological study in recent years. Up to date,circumferential pulmonary vein ablation (CPVA)guided by three-dimensional (3-D) electroanatomic mapping (Carto, USA) has been one of the most favourable procedures for the treatment of AF.

  7. Field enhancement induced laser ablation

    DEFF Research Database (Denmark)

    Fiutowski, Jacek; Maibohm, Christian; Kjelstrup-Hansen, Jakob;

    Sub-diffraction spatially resolved, quantitative mapping of strongly localized field intensity enhancement on gold nanostructures via laser ablation of polymer thin films is reported. Illumination using a femtosecond laser scanning microscope excites surface plasmons in the nanostructures...

  8. Optical properties measurement of the laser-ablated tissues for the combined laser ablation with photodynamic therapy

    Science.gov (United States)

    Honda, Norihiro; Ishii, Katsunori; Awazu, Kunio

    2012-03-01

    Laser ablation therapy combined with photodynamic therapy (PDT) is studied for treatment of advanced cancers. The clinical outcome of PDT may be improved by the accurate knowledge about the light distribution within tissue. Optical properties [absorption coefficient (μa), scattering coefficient (μs), anisotropy factor (g), refractive index, etc.] of tissues help us realizing a light propagation through the tissue. It is important to understand of the effect of laser coagulation formed by laser ablation to PDT. The aim of this study is to estimate of influence of coagulated region to PDT for effective PDT combined laser ablation therapy. We evaluated the optical property of mouse tumor tissue in native and coagulated state using a double integrating sphere system and an inverse Monte Carlo method in the wavelength range from 350 to 1000 nm. After laser ablation, the μa and reduced scattering coefficient spectra of coagulated tissues were increased in the wavelength range from 350 to 1000 nm. The optical penetration depth of coagulated tissues is 1.2-2.9 times lower than the native state in the wavelength range from 350 to 1000 nm. The intensity of the light energy inside the coagulated tissue falls to about 60% of its original value at the end of coagulated layer. The evaluation of light energy distribution by the determination of the tissues optical properties could be useful for optimization of the treatment procedure in combined laser ablation with PDT.

  9. Structural and functional atrial remodeling in patients after catheter and surgical ablation of atrial fibrillation

    Directory of Open Access Journals (Sweden)

    Bockeria L.A.

    2016-03-01

    Full Text Available Atrial fibrillation (AF is the most common supraventricular arrhythmia which occurs in 1.5–2.0% of population. Morbidity of AF increased by 13% over the past two decades. Modern treatment of AF includes drug therapy, catheter radiofrequency ablation and various modifications of Cox Maze operations. The purpose of this review was to assess the atrial remodeling according to world literature. This involved a search of published articles in Medline, Web of Science, PubMed, Cochrane Central Register of Controlled Trials medical databases. During the primary stage of analysis 25 articles of 456 were identified. The researches carried out demonstrate that after catheter ablation and Cox Maze operation in patients with atrial fibrillation left atrium volume decrease, atrial contractile function improvment and sinus rhythm restoration are observed. In the absence of AF recurrence and postoperative atrial arrhythmias in early and late postoperative periods in some patients atrial remodeling is expressed. All data were confirmed by echocardiography, computer tomography and magnetic resonance imaging studies both before and after surgery.

  10. Ablative Approaches for Pulmonary Metastases.

    Science.gov (United States)

    Boyer, Matthew J; Ricardi, Umberto; Ball, David; Salama, Joseph K

    2016-02-01

    Pulmonary metastases are common in patients with cancer for which surgery is considered a standard approach in appropriately selected patients. A number of patients are not candidates for surgery due to a medical comorbidities or the extent of surgery required. For these patients, noninvasive or minimally invasive approaches to ablate pulmonary metastases are potential treatment strategies. This article summarizes the rationale and outcomes for non-surgical treatment approaches, including radiotherapy, radiofrequency and microwave ablation, for pulmonary metastases.

  11. Laser ablation in analytical chemistry.

    Science.gov (United States)

    Russo, Richard E; Mao, Xianglei; Gonzalez, Jhanis J; Zorba, Vassilia; Yoo, Jong

    2013-07-01

    In 2002, we wrote an Analytical Chemistry feature article describing the Physics of Laser Ablation in Microchemical Analysis. In line with the theme of the 2002 article, this manuscript discusses current issues in fundamental research, applications based on detecting photons at the ablation site (LIBS and LAMIS) and by collecting particles for excitation in a secondary source (ICP), and directions for the technology. PMID:23614661

  12. Using the Morris water maze to assess spatial learning and memory in weanling mice.

    Science.gov (United States)

    Barnhart, Christopher D; Yang, Dongren; Lein, Pamela J

    2015-01-01

    Mouse models have been indispensable for elucidating normal and pathological processes that influence learning and memory. A widely used method for assessing these cognitive processes in mice is the Morris water maze, a classic test for examining spatial learning and memory. However, Morris water maze studies with mice have principally been performed using adult animals, which preclude studies of critical neurodevelopmental periods when the cellular and molecular substrates of learning and memory are formed. While weanling rats have been successfully trained in the Morris water maze, there have been few attempts to test weanling mice in this behavioral paradigm even though mice offer significant experimental advantages because of the availability of many genetically modified strains. Here, we present experimental evidence that weanling mice can be trained in the Morris water maze beginning on postnatal day 24. Maze-trained weanling mice exhibit significant improvements in spatial learning over the training period and results of the probe trial indicate the development of spatial memory. There were no sex differences in the animals' performance in these tasks. In addition, molecular biomarkers of synaptic plasticity are upregulated in maze-trained mice at the transcript level. These findings demonstrate that the Morris water maze can be used to assess spatial learning and memory in weanling mice, providing a potentially powerful experimental approach for examining the influence of genes, environmental factors and their interactions on the development of learning and memory.

  13. Using the Morris water maze to assess spatial learning and memory in weanling mice.

    Directory of Open Access Journals (Sweden)

    Christopher D Barnhart

    Full Text Available Mouse models have been indispensable for elucidating normal and pathological processes that influence learning and memory. A widely used method for assessing these cognitive processes in mice is the Morris water maze, a classic test for examining spatial learning and memory. However, Morris water maze studies with mice have principally been performed using adult animals, which preclude studies of critical neurodevelopmental periods when the cellular and molecular substrates of learning and memory are formed. While weanling rats have been successfully trained in the Morris water maze, there have been few attempts to test weanling mice in this behavioral paradigm even though mice offer significant experimental advantages because of the availability of many genetically modified strains. Here, we present experimental evidence that weanling mice can be trained in the Morris water maze beginning on postnatal day 24. Maze-trained weanling mice exhibit significant improvements in spatial learning over the training period and results of the probe trial indicate the development of spatial memory. There were no sex differences in the animals' performance in these tasks. In addition, molecular biomarkers of synaptic plasticity are upregulated in maze-trained mice at the transcript level. These findings demonstrate that the Morris water maze can be used to assess spatial learning and memory in weanling mice, providing a potentially powerful experimental approach for examining the influence of genes, environmental factors and their interactions on the development of learning and memory.

  14. Acute effects of ketamine in the holeboard, the elevated-plus maze, and the social interaction test in Wistar rats.

    Science.gov (United States)

    Silvestre, J S; Nadal, R; Pallarés, M; Ferré, N

    1997-01-01

    Although noncompetitive NMDA receptor antagonists have shown an anxiolyticlike profile in several studies, such effects have not been observed consistently. Previous studies with ketamine, a noncompetitive NMDA antagonist, have employed only shock tests of anxiety based on conflict procedures. In the present experiment, the effect of an acute low dose of ketamine (7 mg/kg) was examined in adult male Wistar rats tested in three nonconflict tests: holeboard, social interaction, and elevated plus-maze paradigms. The results showed that ketamine decreased time spent in active social interaction and the number of rearings and central activity in the social interaction test. It also decreased the number of entries into the percentage of time spent in open arms and the total number of entries in the elevated plus-maze. No significant effect was observed in head dipping in the holeboard test, although the number of crossings did increase. These results suggest an anxiogeniclike effect of ketamine in contrast with results previously described for noncompetitive NMDA receptor antagonists. These effects of ketamine are more similar to those described for stimulant drugs such as caffeine, cocaine, or amphetamine in anxiety tests.

  15. Percutaneous microwave ablation vs radiofrequency ablation in the treatment of hepatocellular carcinoma.

    Science.gov (United States)

    Poulou, Loukia S; Botsa, Evanthia; Thanou, Ioanna; Ziakas, Panayiotis D; Thanos, Loukas

    2015-05-18

    Hepatocellular cancer ranks fifth among cancers and is related to chronic viral hepatitis, alcohol abuse, steatohepatitis and liver autoimmunity. Surgical resection and orthotopic liver transplantation have curative potential, but fewer than 20% of patients are suitable candidates. Interventional treatments are offered to the vast majority of patients. Radiofrequency (RFA) and microwave ablation (MWA) are among the therapeutic modalities, with similar indications which include the presence of up to three lesions, smaller than 3 cm in size, and the absence of extrahepatic disease. The therapeutic effect of both methods relies on thermal injury, but MWA uses an electromagnetic field as opposed to electrical current used in RFA. Unlike MWA, the effect of RFA is partially limited by the heat-sink effect and increased impedance of the ablated tissue. Compared with RFA, MWA attains a more predictable ablation zone, permits simultaneous treatment of multiple lesions, and achieves larger coagulation volumes in a shorter procedural time. Major complications of both methods are comparable and infrequent (approximately 2%-3%), and they include haemorrhage, infection/abscess, visceral organ injury, liver failure, and pneumothorax. RFA may incur the additional complication of skin burns. Nevertheless, there is no compelling evidence for differences in clinical outcomes, including local recurrence rates and survival. PMID:26052394

  16. Percutaneous radiofrequency ablation for osteoid osteoma: How we do it

    International Nuclear Information System (INIS)

    To describe our technique for performing radiofrequency ablation (RFA) in osteoid osteoma and to evaluate the results of treatment. We evaluated 40 patients in whom RFA was performed for osteoid osteomas between October 2005 and February 2008. The lesions were located in the femur (n = 22), tibia (n = 10), humerus (n = 2), acetabulum (n = 2), radius (n = 1), fibula (n = 1), patella (n = 1), and calcaneum (n = 1). The procedure was performed using a standard technique. Technical success was achieved in all patients, with intranidal localization of the needle and complete ablation. All patients were fully weight bearing 2–3 h after the procedure. Successful pain relief was achieved in all patients within 48 h. Immediate complications included a case of minor thermal skin burn and a small cortical chip fracture, which healed on its own. There were no delayed complications. The average follow-up period was 12 months. Two patients (5% of cases) had recurrence of pain after intervals of 5 and 8 months, respectively, following the ablation; this was due to recurrence of the lesion. Complete pain relief was however achieved after a second ablation in both cases. Thus, our primary and secondary clinical success rates were 95 and 100%, respectively. RFA is a safe, quick, minimally invasive, and extremely effective method for the management of osteoid osteomas

  17. 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.

  18. Maze learning by a hybrid brain-computer system

    Science.gov (United States)

    Wu, Zhaohui; Zheng, Nenggan; Zhang, Shaowu; Zheng, Xiaoxiang; Gao, Liqiang; Su, Lijuan

    2016-09-01

    The combination of biological and artificial intelligence is particularly driven by two major strands of research: one involves the control of mechanical, usually prosthetic, devices by conscious biological subjects, whereas the other involves the control of animal behaviour by stimulating nervous systems electrically or optically. However, to our knowledge, no study has demonstrated that spatial learning in a computer-based system can affect the learning and decision making behaviour of the biological component, namely a rat, when these two types of intelligence are wired together to form a new intelligent entity. Here, we show how rule operations conducted by computing components contribute to a novel hybrid brain-computer system, i.e., ratbots, exhibit superior learning abilities in a maze learning task, even when their vision and whisker sensation were blocked. We anticipate that our study will encourage other researchers to investigate combinations of various rule operations and other artificial intelligence algorithms with the learning and memory processes of organic brains to develop more powerful cyborg intelligence systems. Our results potentially have profound implications for a variety of applications in intelligent systems and neural rehabilitation.

  19. Maze learning by a hybrid brain-computer system

    Science.gov (United States)

    Wu, Zhaohui; Zheng, Nenggan; Zhang, Shaowu; Zheng, Xiaoxiang; Gao, Liqiang; Su, Lijuan

    2016-01-01

    The combination of biological and artificial intelligence is particularly driven by two major strands of research: one involves the control of mechanical, usually prosthetic, devices by conscious biological subjects, whereas the other involves the control of animal behaviour by stimulating nervous systems electrically or optically. However, to our knowledge, no study has demonstrated that spatial learning in a computer-based system can affect the learning and decision making behaviour of the biological component, namely a rat, when these two types of intelligence are wired together to form a new intelligent entity. Here, we show how rule operations conducted by computing components contribute to a novel hybrid brain-computer system, i.e., ratbots, exhibit superior learning abilities in a maze learning task, even when their vision and whisker sensation were blocked. We anticipate that our study will encourage other researchers to investigate combinations of various rule operations and other artificial intelligence algorithms with the learning and memory processes of organic brains to develop more powerful cyborg intelligence systems. Our results potentially have profound implications for a variety of applications in intelligent systems and neural rehabilitation. PMID:27619326

  20. Maze learning by a hybrid brain-computer system.

    Science.gov (United States)

    Wu, Zhaohui; Zheng, Nenggan; Zhang, Shaowu; Zheng, Xiaoxiang; Gao, Liqiang; Su, Lijuan

    2016-01-01

    The combination of biological and artificial intelligence is particularly driven by two major strands of research: one involves the control of mechanical, usually prosthetic, devices by conscious biological subjects, whereas the other involves the control of animal behaviour by stimulating nervous systems electrically or optically. However, to our knowledge, no study has demonstrated that spatial learning in a computer-based system can affect the learning and decision making behaviour of the biological component, namely a rat, when these two types of intelligence are wired together to form a new intelligent entity. Here, we show how rule operations conducted by computing components contribute to a novel hybrid brain-computer system, i.e., ratbots, exhibit superior learning abilities in a maze learning task, even when their vision and whisker sensation were blocked. We anticipate that our study will encourage other researchers to investigate combinations of various rule operations and other artificial intelligence algorithms with the learning and memory processes of organic brains to develop more powerful cyborg intelligence systems. Our results potentially have profound implications for a variety of applications in intelligent systems and neural rehabilitation. PMID:27619326

  1. Barnes maze performance of Octodon degus is gender dependent.

    Science.gov (United States)

    Popović, Natalija; Madrid, Juan Antonio; Rol, María Angeles; Caballero-Bleda, María; Popović, Miroljub

    2010-10-15

    Gender differences in spatial navigation have been widely reported in nocturnal rodent species. Here, for the first time we report gender differences in spatial learning and memory of Octodon degus, a long-lived diurnal hystricomorph rodent. In the present study, 16 months old male and female O. degus were tested in the 18-holes Barnes circular maze. The acquisition session consisted of four daily 4 min trials, during 10 days. Seven days later, the retention test was performed. To avoid the effect of hormonal fluctuation on spatial navigation, both the acquisition and the retention tests, were performed in 21-day regular cycling females in a period that corresponds to the diestrus phase of the estrus cycle. At the beginning of the acquisition, female degus were significantly slower than males to find the escape hole, but the situation reversed afterwards. Moreover, during the course of acquisition, females made significantly less reference memory errors, working memory errors as well as omission errors, than males. In both sexes, motivation and learning ceiling effects were reached at days 5-6 of the training. During the acquisition, females used more frequently a spatial strategy, while males preferably applied either serial, random or opposite strategies. The observed cognitive differences between male and female O. degus existed only during the acquisition period but not during the retention, indicating that acquisition and consolidation are differently influenced by gender. PMID:20385170

  2. Unicursal random maze tool path for computer-controlled optical surfacing.

    Science.gov (United States)

    Wang, Chunjin; Wang, Zhenzhong; Xu, Qiao

    2015-12-01

    A novel unicursal random maze tool path is proposed in this paper, which can not only implement uniform coverage of the polishing surfaces, but also possesses randomness and multidirectionality. The simulation experiments along with the practical polishing experiments are conducted to make the comparison of three kinds of paths, including maze path, raster path, and Hilbert path. The experimental results validate that the maze path can warrant uniform polishing and avoid the appearance of the periodical structures in the polished surface. It is also more effective than the Hilbert path in restraining the mid-spatial frequency error in computer-controlled optical surfacing process. PMID:26836670

  3. Unicursal random maze tool path for computer-controlled optical surfacing.

    Science.gov (United States)

    Wang, Chunjin; Wang, Zhenzhong; Xu, Qiao

    2015-12-01

    A novel unicursal random maze tool path is proposed in this paper, which can not only implement uniform coverage of the polishing surfaces, but also possesses randomness and multidirectionality. The simulation experiments along with the practical polishing experiments are conducted to make the comparison of three kinds of paths, including maze path, raster path, and Hilbert path. The experimental results validate that the maze path can warrant uniform polishing and avoid the appearance of the periodical structures in the polished surface. It is also more effective than the Hilbert path in restraining the mid-spatial frequency error in computer-controlled optical surfacing process.

  4. Percutaneous radiofrequency ablation for lung tumors beneath the rib under CT fluoroscopic guidance with gantry tilt

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Takanobu; Yamagami, Takuji; Tanaka, Osamu; Yoshimatsu, Rika; Miura, Hiroshi; Nishimura, Tsunehiko (Dept. of Radiology, Graduate School of Medical Science, Kyoto Prefectural Univ. of Medicine, Kamigyo, Kyoto (Japan)), e-mail: yamagami@koto.kpu-m.ac.jp

    2010-05-15

    Background: Radiofrequency (RF) ablation of lung tumors has become a treatment of choice, especially for unresectable cases. However, RF ablation of small lung lesions located just beneath the rib is difficult. Purpose: To evaluate the efficacy and safety of gantry tilting for the performance of RF ablation of peripheral lesions located beneath the rib. Material and Methods: Our study was based on 18 of 293 lesions in the lung for which RF ablation was performed under CT scan fluoroscopic guidance at our institution between October 2004 and March 2009. For these 18 lesions, RF ablation was performed with gantry tilting because a rib blocked visualization of the RF ablation route even after other attempts had been made to change the relationship between the target and the rib. Results: All RF needles, with only one exception, were successfully advanced to hit the tumor. The commonest complication was a pneumothorax, which occurred in seven procedures. No serious complications occurred. The progression-free rates were 82.4% at 6 months, 62.5% at 12 months, and 30% at 24 months. Mean local progression-free duration was 17.6+-11.6 months (range 4-36 months). Conclusion: RF ablation under CT scan fluoroscopic guidance with gantry tilt is a useful and safe technique for RF ablation of lung nodules located beneath the rib

  5. Una técnica para la extirpación de los órganos vomeronasales en el armadillo Chaetophractus villosus. Abordaje desde la cavidad bucal - A surgical procedure for the ablation of the Vomeronasal Organs in the armadillo Chaetophractus villosus. Approach from oral cavity

    Directory of Open Access Journals (Sweden)

    Iodice, O. H.

    2010-03-01

    Full Text Available ResumenSe describen los pasos de un procedimiento quirúrgico para la extirpación bilateral de los órganos vomeronasales del armadillo Chaetophractus villosus (Mammalia, Xenarthra. Cada órgano está ubicado en el piso de la cavidad nasal, adosado a cada lado del tabique nasal. Los órganos se abordan a través de unaabertura practicada en el techo de la cavidad bucal. Este procedimiento se realiza bajo lupa estereoscópica y permite una visualización directa de los órganos Los mismos se destruyen por medio de una fresa accionada por un torno. De este modo se tiene la certeza de una ablación total. La posterior verificación por mediode cortes histológicos no es por lo tanto necesaria. Esto representa una ventaja importante puesto que las características físicas del hueso de estos animales requieren períodos largos de ablandamiento (generalmente alrededor tres meses. SummaryA surgical procedure for the bilateral ablation of the vomeronasal organs of the armadillo Chaetophractus villosus (Mammalia, Xenarthra is described. The organs are approached from the roof of the oral cavity through a longitudinal slit performed with a dental drill. This procedure is performed under magnifying stereoscopic lens and permits the direct visualization of the organs. Those structures are then destroyed with the dental drill. This provides certainty of totalablation. As a consequence, verification by means of histological sections is not needed. This represents an important advantage since the physical characteristics of the bone of these animals require long periods of softening (usually around three months.

  6. 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. PMID:26174606

  7. Ablation of incessant ventricular tachycardia by epicardial approach. A case report

    International Nuclear Information System (INIS)

    A ventricular tachycardia (VT) is relentless when it persists longer than 24 hours despite completing treatment with at least two antiarrhythmic drugs, electrical cardioversion (CEV) or overstimulation. It is a dramatic clinical situation, with high mortality. Catheter ablation endocardial using radio frequency is the treatment of choice, although it is a highly complex and procedure with a success rate of between 45% and 75% in different publications. One reason for these results, sometimes discouraging of endocardial ablation, is that circuits of re-entry, basic mechanism of this arrhythmia, often are subepicardicos. We present a case of incessant TV referred to our service in which an epicardial ablation was performed

  8. The advent of ultrasound-guided ablation techniques in nodular thyroid disease

    DEFF Research Database (Denmark)

    Papini, Enrico; Pacella, Claudio M; Misischi, Irene;

    2014-01-01

    non-functioning thyroid nodules that grow or become symptomatic, trained operators may safely induce, with a single session of laser ablation treatment or radiofrequency ablation, a 50% volume decrease and, in parallel, improve local symptoms. In contrast, hyperfunctioning nodules remain best treated...... and thermal ablation with laser or radiofrequency have been thoroughly evaluated, and are accessible procedures in specialized centres. In clinical practice, relapsing thyroid cysts are effectively managed with percutaneous ethanol injection treatment, which should be considered therapy of choice. In solid...

  9. Impact of different ablation strategies on the delayed cure after trans-catheter ablation for treating patients with atrial fibrillation

    Institute of Scientific and Technical Information of China (English)

    DONG Jian-zeng; MA Chang-sheng; LIU Xing-peng; LONG De-yong; LIU Xiao-qing; WANG Jing; Fang Dong-ping; HAO Peng; LI Yong-sheng; LIU Chuang

    2005-01-01

    Background Delayed cure had been observed in recurrent cases after index ablation of atrial fibrillation (AF), however, its mechanism and incidence have not been elucidated in detail. This study aims to investigate the impact of different ablation strategies on the incidence of delayed cure and its possible mechanisms after trans-catheter ablation of AF. Methods One hundred and fifty-one consecutive cases with highly symptomatic, drug refractory AF were included in this study [M/F=109/42, mean age (56.0±11.2) (18-79) years]. Segmental pulmonary vein ablation (SPVA) was performed in 83 patients with the guidance of circular mapping catheter (SPVA Group), circumferential PV linear ablation (CPVA) was carried out in the rest 68 cases under the guidance of 3 dimensional mapping system in conjunction with circular mapping catheter (CPVA Group). Delayed cure was defined as that early recurrence of atrial tachyarrhythmias (AF, atrial tachycardia, or atrial flutter) after ablation procedure was no longer observed during subsequent follow-up, and stable sinus rhythm was maintained ≥2 months. Results Early recurrence of atrial tachyarrhythmias was detected in 41 cases from SPVA group and 23 cases from CPVA group, and delayed cure occurred in 21.9% (9/41) of the cases from SPVA group and 47.8% (11/23) of the cases from CPVA group, more delayed cure in later group was observed (P<0.05). Meanwhile, patients in SPVA group took a longer time to achieve a delayed cure [(27.0±18.0) days vs (14.0±8.1) days, P<0.05], and presented more recurrent episodes [(3.50±1.08) times a week vs (2.42±1.11) times a week, P<0.05]. However, recurrent episodes after index ablation were markedly decreased in cases with delayed cure from both groups (P<0.05). Conclusions Despite of an early recurrence of atrial tachyarrhythimas after index ablation of AF, delayed cure occurs in a significant number of patients undergoing either SPVA or CPVA. However, different ablation strategies place

  10. 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....

  11. Esophageal papilloma: Flexible endoscopic ablation byradiofrequency

    Institute of Scientific and Technical Information of China (English)

    Gianmattia del Genio; Federica del Genio; Pietro Schettino; Paolo Limongelli; Salvatore Tolone; Luigi Brusciano; Manuela Avellino; Chiara Vitiello; Giovanni Docimo; Angelo Pezzullo; Ludovico Docimo

    2015-01-01

    Squamous papilloma of the esophagus is a rare benignlesion of the esophagus. Radiofrequency ablation is anestablished endoscopic technique for the eradication ofBarrett esophagus. No cases of endoscopic ablation ofesophageal papilloma by radiofrequency ablation (RFA)have been reported. We report a case of esophagealpapilloma successfully treated with a single sessionof radiofrequency ablation. Endoscopic ablation ofthe lesion was achieved by radiofrequency using anew catheter inserted through the working channelof endoscope. The esophageal ablated tissue wasremoved by a specifically designed cup. Completeablation was confirmed at 3 mo by endoscopy withbiopsies. This case supports feasibility and safety of asa new potential indication for BarrxTM RFA in patientswith esophageal papilloma.

  12. Durable Pulmonary Vein Isolation: The Holy Grail of Atrial Fibrillation Ablation

    Directory of Open Access Journals (Sweden)

    Duy Thai Nguyen; William H. Sauer

    2010-10-01

    Full Text Available The inability to achieve durable pulmonary vein isolation remains a major limitation to catheter ablation for the treatment of atrial fibrillation (AF. In this review, we discuss the research performed over the past decade investigating methods to improve lesion permanence for the goal of durable pulmonary vein isolation (PVI. Investigations evaluating procedural techniques, adjunctive pharmacologic therapy, and newer energy sources designed to improve ablation lesion permanence are discussed.

  13. Entwicklung und Validierung eines Therapieplanungssystems für die in-situ-Ablation maligner Lebertumore

    OpenAIRE

    Lehmann, Kai

    2014-01-01

    Surgical resection is the established curative treatment of liver metastases. However, only few patients are eligible for resection. In thermal in-situ ablation techniques, such as laser-induced thermotherapy (LITT) and radiofrequency ablation (RFA), a liver tumor is punctured with a needle-like applicator and is destroyed by thermal energy in-situ. These procedures are characterized by a less invasive application and repeatable therapy. Currently, the technique is mostly used in palliative i...

  14. Durable Pulmonary Vein Isolation: The Holy Grail of Atrial Fibrillation Ablation

    Directory of Open Access Journals (Sweden)

    Darrat Y; Morales G; Shah J; Di Biase L; Natale A; Elayi CS

    2014-04-01

    Full Text Available The inability to achieve durable pulmonary vein isolation (PVI remains a major limitation to catheter ablation for the treatment of atrial fibrillation (AF, potentially resulting in AF recurrence. In this review, we discuss the research performed investigating methods to improve lesion permanence for the goal of durable PVI. Investigations evaluating procedural techniques, various catheters utilized, adjunctive pharmacologic therapy, and novel energy sources designed to improve ablation lesion permanence are discussed.

  15. Idiopathic ventricular tachycardia: transcatheter ablation or antiarrhythmic drugs?

    Directory of Open Access Journals (Sweden)

    Claudio Tondo; Corrado Carbucicchio; Antonio Dello Russo; Benedetta Majocchi; Martina Zucchetti; Francesca Pizzamiglio; Fabrizio Bologna; Fabio Cattaneo; Daniele Colombo; Eleonora Russo; Michela Casella

    2015-02-01

    Full Text Available Introduction Ventricular tachycardia or frequent premature ventricular contractions (PVCs can occur in the absence of any detectable structural heart disease. In this clinical setting, these arrhythmias are termed idiopathic. Usually, they carry a benign prognosis and any potential ablative intervention is carried out if patients are highly symptomatic or, more importantly, if frequent ventricular arrhythmias can lead to ventricular dysfunction. Methods In this paper, different forms of idiopathic ventricular tachycardia are reviewed. Outflow tract ventricular tachycardia from the right ventricle is the most frequent form of the so-called idiopathic ventricular tachycardia. Other forms of idiopathic ventricular arrhythmias include ventricular tachycardia/PVCs arising from tricuspid annulus, from the mitral annulus, inter-fascicular ventricular tachycardia and papillary muscle ventricular tachycardia. When interventional treatment is deemed necessary, detailed mapping ( earliest activation during VT/PVC, pace mapping is crucial as to identify the successful ablation site. Catheter ablation more than antiarrhythmic drug treatment is usually highly effective in eliminating idiopathic ventricular arrhythmias and providing prevention of recurrence. Conclusion Idiopathic VTs are not considered life-threatening arrhythmias and, prevention of recurrences is often achieved by means of catheter ablation that provides an improvement of quality of life. The overall acute success rate of catheter ablation is about 85-90% with a long–term prevention of arrhythmia recurrence of about 75-80%. It is advisable that the procedure is carried out by electrophysiologists with expertise in VT catheter ablation and extensive knowledge of cardiac anatomy as to ensure a high success rate and reduce the likelihood of major complications.

  16. Slime mould solves maze in one pass ... assisted by gradient of chemo-attractants

    CERN Document Server

    Adamatzky, Andrew

    2011-01-01

    Plasmodium of Physarum polycephalum is a large cell, visible by unaided eye, which exhibits sophisticated patterns of foraging behaviour. The plasmodium's behaviour is well interpreted in terms of computation, where data are spatially extended configurations of nutrients and obstacles, and results of computation are networks of protoplasmic tubes formed by the plasmodium. In laboratory experiments and numerical simulation we show that if plasmodium of Physarum is inoculated in a maze's peripheral channel and an oat flake (source of attractants) in a the maze's central chamber then the plasmodium grows toward target oat flake and connects the flake with the site of original inoculation with a pronounced protoplasmic tube. The protoplasmic tube represents a path in the maze. The plasmodium solves maze in one pass because it is assisted by a gradient of chemo-attractants propagating from the target oat flake.

  17. Fast escape of a quantum walker from an integrated photonic maze

    Science.gov (United States)

    Caruso, Filippo; Crespi, Andrea; Ciriolo, Anna Gabriella; Sciarrino, Fabio; Osellame, Roberto

    2016-06-01

    Escaping from a complex maze, by exploring different paths with several decision-making branches in order to reach the exit, has always been a very challenging and fascinating task. Wave field and quantum objects may explore a complex structure in parallel by interference effects, but without necessarily leading to more efficient transport. Here, inspired by recent observations in biological energy transport phenomena, we demonstrate how a quantum walker can efficiently reach the output of a maze by partially suppressing the presence of interference. In particular, we show theoretically an unprecedented improvement in transport efficiency for increasing maze size with respect to purely quantum and classical approaches. In addition, we investigate experimentally these hybrid transport phenomena, by mapping the maze problem in an integrated waveguide array, probed by coherent light, hence successfully testing our theoretical results. These achievements may lead towards future bio-inspired photonics technologies for more efficient transport and computation.

  18. Femtosecond laser ablation of enamel

    Science.gov (United States)

    Le, Quang-Tri; Bertrand, Caroline; Vilar, Rui

    2016-06-01

    The surface topographical, compositional, and structural modifications induced in human enamel by femtosecond laser ablation is studied. The laser treatments were performed using a Yb:KYW chirped-pulse-regenerative amplification laser system (560 fs and 1030 nm) and fluences up to 14 J/cm2. The ablation surfaces were studied by scanning electron microscopy, grazing incidence x-ray diffraction, and micro-Raman spectroscopy. Regardless of the fluence, the ablation surfaces were covered by a layer of resolidified material, indicating that ablation is accompanied by melting of hydroxyapatite. This layer presented pores and exploded gas bubbles, created by the release of gaseous decomposition products of hydroxyapatite (CO2 and H2O) within the liquid phase. In the specimen treated with 1-kHz repetition frequency and 14 J/cm2, thickness of the resolidified material is in the range of 300 to 900 nm. The micro-Raman analysis revealed that the resolidified material contains amorphous calcium phosphate, while grazing incidence x-ray diffraction analysis allowed detecting traces of a calcium phosphate other than hydroxyapatite, probably β-tricalcium phosphate Ca3), at the surface of this specimen. The present results show that the ablation of enamel involves melting of enamel's hydroxyapatite, but the thickness of the altered layer is very small and thermal damage of the remaining material is negligible.

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

    Directory of Open Access Journals (Sweden)

    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.

  20. Effects of an Early Experience Involving Training in a T-Maze Under either Denial or Receipt of Expected Reward through Maternal Contact.

    Science.gov (United States)

    Stamatakis, Antonios; Diamantopoulou, Anastasia; Panagiotaropoulos, Theofanis; Raftogianni, Androniki; Stylianopoulou, Fotini

    2013-01-01

    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. While male RER animals assume a reactive coping style in this test, and showed increased freezing during both contextual and cued memory recall following fear conditioning. PMID:24298269

  1. Evaluation of neurotransmitters involved in the anxiolytic and panicolytic effect of the aqueous fraction of Paullinia cupana (guaraná in elevated T maze

    Directory of Open Access Journals (Sweden)

    Marcel P. Rangel

    2013-04-01

    Full Text Available This study investigated the effects of repeatedly administration of an aqueous fraction of Paullinia cupana Kunth, Sapindaceae (guaraná seeds (8 mg/kg on rats submitted to the elevated T-maze, model of generalized anxiety and panic disorders. The selective serotonin reuptake inhibitor paroxetine (3 mg/kg, was used as a positive control. To evaluate possible neurotransmissions involvement, ineffective doses of metergoline (3 mg/kg - non-selective serotonin receptor antagonist, sulpiride (20 mg/kg - non-selective dopaminergic receptor antagonist or ketamine (0.125 mg/kg - non-selective glutamate receptor antagonist were acutely administered in association with the aqueous fraction of P. cupana. Both aqueous fraction and paroxetine decrease the inhibitory avoidance latencies of the elevated T-maze, indicating anxiolytic effect and increased one-way escape latencies from the open arm of the elevated T-maze, indicating a panicolytic effect. The pre-treatment with metergoline, sulpiride and ketamine blocked the anxiolytic effect of aqueous fraction. The panicolytic effect of aqueous fraction was blocked by both metergoline and sulpiride. These results show that the serotonergic, dopaminergic and glutamatergic neurotransmission systems are involved in anxiolytic effect promoted by aqueous fraction, whereas only the serotonergic and the dopaminergic neurotransmission systems are involved in the panicolytic effect promoted by aqueous fraction of P. cupana. The effects produced by paroxetine, were blocked only by metergoline, validating this experimental procedure.

  2. Radial Maze Analog for Pigeons: Evidence for Flexible Coding Strategies May Result from Faulty Assumptions

    OpenAIRE

    Gipson, Cassandra D.; DiGian, Kelly A.; Miller, Holly C.; Zentall, Thomas R

    2008-01-01

    Previous research with the radial maze has found evidence that rats can remember both places that they have already been (retrospective coding) and places they have yet to visit (prospective coding; Cook, Brown, & Riley, 1985). Such dual coding also has been found in pigeons using a radial maze analog in which insertion of a delay at different points during a trial affects performance differentially depending on where in the trial it is inserted. When a delay is interpolated either early or l...

  3. Detailed classification of swimming paths in the Morris Water Maze: multiple strategies within one trial

    OpenAIRE

    Tiago V. Gehring; Gediminas Luksys; Carmen Sandi; Eleni Vasilaki

    2015-01-01

    The Morris Water Maze is a widely used task in studies of spatial learning with rodents. Classical performance measures of animals in the Morris Water Maze include the escape latency, and the cumulative distance to the platform. Other methods focus on classifying trajectory patterns to stereotypical classes representing different animal strategies. However, these approaches typically consider trajectories as a whole, and as a consequence they assign one full trajectory to one class, whereas a...

  4. Characteristics of P wave in Patients with Sinus Rhythm after Maze Operation

    OpenAIRE

    Park, Hyo Eun; Kim, Kyung-Hwan; Kim, Ki-Bong; Ahn, Hyuk; Choi, Yun-Shik; Oh, Seil

    2010-01-01

    Maze operation could alter P wave morphology in electrocardiogram (ECG), which might prevent exact diagnosis of the cardiac rhythm of patients. However, characteristics of P wave in patients with sinus rhythm after the operation have not been elucidated systematically. Consecutive patients who underwent the modified Cox Maze operation from January to December 2007 were enrolled. The standard 12-lead ECG and echocardiography were evaluated in patients who had sinus rhythm at 6 months after the...

  5. Role of Optical Coherence Tomography on Corneal Surface Laser Ablation

    OpenAIRE

    Ventura, Bruna V.; Moraes, Haroldo V.; Newton Kara-Junior; Santhiago, Marcony R.

    2012-01-01

    This paper focuses on reviewing the roles of optical coherence tomography (OCT) on corneal surface laser ablation procedures. OCT is an optical imaging modality that uses low-coherence interferometry to provide noninvasive cross-sectional imaging of tissue microstructure in vivo. There are two types of OCTs, each with transverse and axial spatial resolutions of a few micrometers: the time-domain and the fourier-domain OCTs. Both have been increasingly used by refractive surgeons and have spec...

  6. Skin Burn at the Site of Indifferent Electrode after Radiofrequency Catheter Ablation of AV Node for Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Subba Reddy Vanga, MBBS

    2008-07-01

    Full Text Available Radiofrequency Ablation of AV node with permanent pacemaker has been used to achieve rate control in persistent symptomatic atrial fibrillation. Although RF Ablation is safe, complications may occur in up to 3% of the procedures. A rare complication of 2nd degree skin burn at indifferent electrode site has been described here. This report highlights the rare but possible complication in patients undergoing such a procedure and help in preventing by taking appropriate measures.

  7. Skin Burn at the Site of Indifferent Electrode after Radiofrequency Catheter Ablation of AV Node for Atrial Fibrillation.

    Directory of Open Access Journals (Sweden)

    Dhanunjaya R Lakkireddy

    2008-07-01

    Full Text Available Radiofrequency Ablation of AV node with permanent pacemaker has been used to achieve rate control in persistent symptomatic atrial fibrillation. Although RF Ablation is safe, complications may occur in up to 3% of the procedures. A rare complication of 2nd degree skin burn at indifferent electrode site has been described here. This report highlights the rare but possible complication in patients undergoing such a procedure and help in preventing by taking appropriate measures.

  8. LAPAROSCOPIC NEPHRECTOMY USING RADIOFREQUENCY THERMAL ABLATION

    Directory of Open Access Journals (Sweden)

    B. Ya. Alekseev

    2012-01-01

    Full Text Available The wide use of current diagnostic techniques, such as ultrasound study, computed tomography, and magnetic resonance imaging, has led to significantly increased detection rates for disease in its early stages. This gave rise to a change in the standards for the treatment of locally advanced renal cell carcinoma (RCC. Laparoscopic nephrectomy (LN has recently become the standard treatment of locally advanced RCC in the clinics having much experience with laparoscopic surgery. The chief drawback of LN is difficulties in maintaining intraoperative hemostasis and a need for creating renal tissue ischemia. The paper gives the intermediate results of application of the new procedure of LN using radiofrequency thermal ablation in patients with non-ischemic early-stage RCC.

  9. Surgical ablation devices for atrial fibrillation.

    Science.gov (United States)

    Lall, Shelly C; Damiano, Ralph J

    2007-12-01

    The introduction of ablation technology has revolutionized the surgical treatment of atrial fibrillation (AF). It has greatly simplified surgical approaches and has significantly increased the number of procedures being performed. Various energy sources have been used clinically, including cryoablation, radiofrequency, microwave, laser, and high-frequency ultrasound. The goal of these devices is to create conduction block to either block activation wavefronts or to isolate the triggers of AF. All present devices have been shown to have clinical efficacy in some patients. The devices each have their unique advantages and disadvantages. It is important that surgeons develop accurate dose-response curves for new devices in clinically relevant models on both the arrested and beating heart. This will allow the appropriate use of technology to facilitate AF surgery. PMID:18175210

  10. Radiofrequency ablation of a misdiagnosed Brodie's abscess.

    Science.gov (United States)

    Chan, Rs; Abdullah, Bjj; Aik, S; Tok, Ch

    2011-04-01

    Radiofrequency ablation (RFA) therapy is recognised as a safe and effective treatment option for osteoid osteoma. This case report describes a 27-year-old man who underwent computed tomography (CT)-guided percutaneous RFA for a femoral osteoid osteoma, which was diagnosed based on his clinical presentation and CT findings. The patient developed worsening symptoms complicated by osteomyelitis after the procedure. His clinical progression and subsequent MRI findings had led to a revised diagnosis of a Brodie's abscess, which was further supported by the eventual resolution of his symptoms following a combination of antibiotics treatment and surgical irrigations. This case report illustrates the unusual MRI features of osteomyelitis mimicking soft tissue tumours following RFA of a misdiagnosed Brodie's abscess and highlights the importance of a confirmatory histopathological diagnosis for an osteoid osteoma prior to treatment.

  11. Microwave ablation of hepatocellular carcinoma.

    Science.gov (United States)

    Poggi, Guido; Tosoratti, Nevio; Montagna, Benedetta; Picchi, Chiara

    2015-11-01

    Although surgical resection is still the optimal treatment option for early-stage hepatocellular carcinoma (HCC) in patients with well compensated cirrhosis, thermal ablation techniques provide a valid non-surgical treatment alternative, thanks to their minimal invasiveness, excellent tolerability and safety profile, proven efficacy in local disease control, virtually unlimited repeatability and cost-effectiveness. Different energy sources are currently employed in clinics as physical agents for percutaneous or intra-surgical thermal ablation of HCC nodules. Among them, radiofrequency (RF) currents are the most used, while microwave ablations (MWA) are becoming increasingly popular. Starting from the 90s', RF ablation (RFA) rapidly became the standard of care in ablation, especially in the treatment of small HCC nodules; however, RFA exhibits substantial performance limitations in the treatment of large lesions and/or tumors located near major heat sinks. MWA, first introduced in the Far Eastern clinical practice in the 80s', showing promising results but also severe limitations in the controllability of the emitted field and in the high amount of power employed for the ablation of large tumors, resulting in a poor coagulative performance and a relatively high complication rate, nowadays shows better results both in terms of treatment controllability and of overall coagulative performance, thanks to the improvement of technology. In this review we provide an extensive and detailed overview of the key physical and technical aspects of MWA and of the currently available systems, and we want to discuss the most relevant published data on MWA treatments of HCC nodules in regard to clinical results and to the type and rate of complications, both in absolute terms and in comparison with RFA. PMID:26557950

  12. Femtosecond laser ablation of dentin

    International Nuclear Information System (INIS)

    The surface morphology, structure and composition of human dentin treated with a femtosecond infrared laser (pulse duration 500 fs, wavelength 1030 nm, fluences ranging from 1 to 3 J cm-2) was studied by scanning electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The average dentin ablation threshold under these conditions was 0.6 ± 0.2 J cm-2 and the ablation rate achieved in the range 1 to 2 µm/pulse for an average fluence of 3 J cm-2. The ablation surfaces present an irregular and rugged appearance, with no significant traces of melting, deformation, cracking or carbonization. The smear layer was entirely removed by the laser treatment. For fluences only slightly higher than the ablation threshold the morphology of the laser-treated surfaces was very similar to the dentin fracture surfaces and the dentinal tubules remained open. For higher fluences, the surface was more porous and the dentin structure was partially concealed by ablation debris and a few resolidified droplets. Independently on the laser processing parameters and laser processing method used no sub-superficial cracking was observed. The dentin constitution and chemical composition was not significantly modified by the laser treatment in the processing parameter range used. In particular, the organic matter is not preferentially removed from the surface and no traces of high temperature phosphates, such as the β-tricalcium phosphate, were observed. The achieved results are compatible with an electrostatic ablation mechanism. In conclusion, the high beam quality and short pulse duration of the ultrafast laser used should allow the accurate preparation of cavities, with negligible damage of the underlying material. (paper)

  13. Microwave ablation of hepatocellular carcinoma

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    Although surgical resection is still the optimal treatmentoption for early-stage hepatocellular carcinoma(HCC) in patients with well compensated cirrhosis,thermal ablation techniques provide a valid nonsurgicaltreatment alternative, thanks to their minimalinvasiveness, excellent tolerability and safety profile,proven efficacy in local disease control, virtuallyunlimited repeatability and cost-effectiveness. Differentenergy sources are currently employed in clinics asphysical agents for percutaneous or intra-surgicalthermal ablation of HCC nodules. Among them, radiofrequency(RF) currents are the most used, whilemicrowave ablations (MWA) are becoming increasinglypopular. Starting from the 90s', RF ablation (RFA) rapidlybecame the standard of care in ablation, especially inthe treatment of small HCC nodules; however, RFAexhibits substantial performance limitations in thetreatment of large lesions and/or tumors located nearmajor heat sinks. MWA, first introduced in the FarEastern clinical practice in the 80s', showing promisingresults but also severe limitations in the controllabilityof the emitted field and in the high amount of poweremployed for the ablation of large tumors, resultingin a poor coagulative performance and a relativelyhigh complication rate, nowadays shows better resultsboth in terms of treatment controllability and of overallcoagulative performance, thanks to the improvementof technology. In this review we provide an extensiveand detailed overview of the key physical and technicalaspects of MWA and of the currently available systems,and we want to discuss the most relevant published dataon MWA treatments of HCC nodules in regard to clinicalresults and to the type and rate of complications, both inabsolute terms and in comparison with RFA.

  14. 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

  15. Transhemangioma Ablation of Hepatocellular Carcinoma

    International Nuclear Information System (INIS)

    Radiofrequency ablation (RFA) is a well-established treatment modality in the treatment of early hepatocellular carcinoma (HCC) [1]. Safe trajectory of the RFA probe is crucial in decreasing collateral tissue damage and unwarranted probe transgression. As a percutaneous technique, however, the trajectory of the needle is sometimes constrained by the available imaging plane. The presence of a hemangioma beside an HCC is uncommon but poses the question of safety related to probe transgression. We hereby describe a case of transhemangioma ablation of a dome HCC.

  16. Transhemangioma Ablation of Hepatocellular Carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Pua, Uei, E-mail: druei@yahoo.com [Tan Tock Seng Hospital, Department of Diagnostic Radiology (Singapore)

    2012-12-15

    Radiofrequency ablation (RFA) is a well-established treatment modality in the treatment of early hepatocellular carcinoma (HCC) [1]. Safe trajectory of the RFA probe is crucial in decreasing collateral tissue damage and unwarranted probe transgression. As a percutaneous technique, however, the trajectory of the needle is sometimes constrained by the available imaging plane. The presence of a hemangioma beside an HCC is uncommon but poses the question of safety related to probe transgression. We hereby describe a case of transhemangioma ablation of a dome HCC.

  17. Catheter ablation of parahisian premature ventricular complex.

    Science.gov (United States)

    Kim, Jun; Kim, Jeong Su; Park, Yong Hyun; Kim, June Hong; Chun, Kook Jin

    2011-12-01

    Catheter ablation is performed in selected patients with a symptomatic premature ventricular complex (PVC) or PVC-induced cardiomyopathy. Ablation of PVC from the His region has a high risk of inducing a complete atrioventricular block. Here we report successful catheter ablation of a parahisian PVC in a 63-year-old man.

  18. Soft thrombus formation in radiofrequency catheter ablation

    NARCIS (Netherlands)

    Demolin, JM; Eick, OJ; Munch, K; Koullick, E; Nakagawa, H; Wittkampf, FHM

    2002-01-01

    During RF catheter ablation, local temperature elevation can result in coagulum formation on the ablation electrode, resulting in impedance rise. A recent study has also demonstrated the formation of a so-called soft thrombus during experimental ablations. This deposit poorly adhered to the catheter

  19. Ablated tektite from the central Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Glass, B.P.; Chapman, D.R.; ShyamPrasad, M.

    A well-preserved ablated (button-shaped) tektite recovered from the surface sediments of the central Indian Ocean lacks flow ridges and has apparently undergone ablation of 6.9 to 7.9 mm. The lack of flow ridges and amount of ablation indicate that...

  20. Catheter ablation of atrial fibrillation in the elderly

    Science.gov (United States)

    Lioni, Louiza; Letsas, Konstantinos P.; Efremidis, Michael; Vlachos, Konstantinos; Giannopoulos, Georgios; Kareliotis, Vasileios; Deftereos, Spyridon; Sideris, Antonios

    2014-01-01

    Background Atrial fibrillation (AF) catheter ablation has emerged as a promising treatment strategy for AF, but has not been widely adopted in the elderly population. The present study aimed to determine the safety and efficacy of AF catheter ablation in the elderly population. Methods and Results The study population consisted of 316 patients with paroxysmal AF who underwent left atrial ablation. Ninety-five patients were ≥ 65 years (48 males, mean age 68.9 ± 3.0 years old) and 221 patients were < 65 years old (130 males, mean age 52.5 ± 10.4 years old). After a mean follow-up period of 34.0 ± 15.1 months, 55 (57.9%) patients in the elderly group were free from arrhythmia recurrence compared with 149 (67.4%) patients in the younger group (P = 0.169). Procedural complications were uncommon in both study groups. In logistic regression analysis, left atrial diameter (P = 0.003), hypertension (P = 0.001), dyslipidemia (P = 0.039), and coronary artery disease (P = 0.018) were independent predictors of AF recurrence in the elderly population. Conclusions Catheter ablation of AF is safe and effective in older patients. Invasive strategies should be considered as an alternative choice in symptomatic elderly patients with AF. PMID:25593577

  1. Catheter ablation of atrial fibrillation in the elderly

    Institute of Scientific and Technical Information of China (English)

    Louiza Lioni; Konstantinos P Letsas; Michael Efremidis; Konstantinos Vlachos; Georgios Giannopoulos; Vasileios Kareliotis; Spyridon Deftereos; Antonios Sideris

    2014-01-01

    Background Atrial fibrillation (AF) catheter ablation has emerged as a promising treatment strategy for AF, but has not been widely adopted in the elderly population. The present study aimed to determine the safety and efficacy of AF catheter ablation in the elderly popula-tion. Methods and Results The study population consisted of 316 patients with paroxysmal AF who underwent left atrial ablation. Ninety-five patients were≥65 years (48 males, mean age 68.9 ± 3.0 years old) and 221 patients were<65 years old (130 males, mean age 52.5 ± 10.4 years old). After a mean follow-up period of 34.0 ± 15.1 months, 55 (57.9%) patients in the elderly group were free from ar-rhythmia recurrence compared with 149 (67.4%) patients in the younger group (P=0.169). Procedural complications were uncommon in both study groups. In logistic regression analysis, left atrial diameter (P=0.003), hypertension (P=0.001), dyslipidemia (P=0.039), and coronary artery disease (P=0.018) were independent predictors of AF recurrence in the elderly population. Conclusions Catheter ablation of AF is safe and effective in older patients. Invasive strategies should be considered as an alternative choice in symptomatic elderly patients with AF.

  2. Robotic-assisted thermal ablation of liver tumours

    International Nuclear Information System (INIS)

    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.)

  3. 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.)

  4. Regional pericarditis status post cardiac ablation: A case report

    Directory of Open Access Journals (Sweden)

    Joseph Orme

    2014-01-01

    Full Text Available Context: Regional pericarditis is elusive and difficult to diagnosis. Healthcare providers should be familiar with post-cardiac ablation complications as this procedure is now widespread and frequently performed. The management of regional pericarditis differs greatly from that of acute myocardial infarction. Case report: A 52 year-old male underwent atrial fibrillation ablation and developed severe mid-sternal chest pain the following day with electrocardiographic findings suggestive of acute myocardial infarction, and underwent coronary angiography, a left ventriculogram, and 2D transthoracic echocardiogram, all of which were unremarkable without evidence of obstructive coronary disease, wall motion abnormalities, or pericardial effusions. Ultimately, the patient was diagnosed with regional pericarditis. After diagnosis, the patient′s presenting symptoms resolved with treatment including nonsteroidal anti-inflammatory agents and colchicine. Conclusion: This is the first reported case study of regional pericarditis status post cardiac ablation. Electrocardiographic findings were classic for an acute myocardial infarction; however, coronary angiography and left ventriculogram demonstrated no acute coronary occlusion or ventricular wall motion abnormalities. Healthcare professionals must remember that the electrocardiographic findings in pericarditis are not always classic and that pericarditis can occur status post cardiac ablation.

  5. Factors Associated with Recurrence of Varicose Veins after Thermal Ablation: Results of The Recurrent Veins after Thermal Ablation Study

    Directory of Open Access Journals (Sweden)

    R. G. Bush

    2014-01-01

    Full Text Available Background. The goal of this retrospective cohort study (REVATA was to determine the site, source, and contributory factors of varicose vein recurrence after radiofrequency (RF and laser ablation. Methods. Seven centers enrolled patients into the study over a 1-year period. All patients underwent previous thermal ablation of the great saphenous vein (GSV, small saphenous vein (SSV, or anterior accessory great saphenous vein (AAGSV. From a specific designed study tool, the etiology of recurrence was identified. Results. 2,380 patients were evaluated during this time frame. A total of 164 patients had varicose vein recurrence at a median of 3 years. GSV ablation was the initial treatment in 159 patients (RF: 33, laser: 126, 52 of these patients had either SSV or AAGSV ablation concurrently. Total or partial GSV recanalization occurred in 47 patients. New AAGSV reflux occurred in 40 patients, and new SSV reflux occurred in 24 patients. Perforator pathology was present in 64% of patients. Conclusion. Recurrence of varicose veins occurred at a median of 3 years after procedure. The four most important factors associated with recurrent veins included perforating veins, recanalized GSV, new AAGSV reflux, and new SSV reflux in decreasing frequency. Patients who underwent RF treatment had a statistically higher rate of recanalization than those treated with laser.

  6. Interventional radiology neck procedures.

    Science.gov (United States)

    Zabala Landa, R M; Korta Gómez, I; Del Cura Rodríguez, J L

    2016-05-01

    Ultrasonography has become extremely useful in the evaluation of masses in the head and neck. It enables us to determine the anatomic location of the masses as well as the characteristics of the tissues that compose them, thus making it possible to orient the differential diagnosis toward inflammatory, neoplastic, congenital, traumatic, or vascular lesions, although it is necessary to use computed tomography or magnetic resonance imaging to determine the complete extension of certain lesions. The growing range of interventional procedures, mostly guided by ultrasonography, now includes biopsies, drainages, infiltrations, sclerosing treatments, and tumor ablation.

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

    Energy Technology Data Exchange (ETDEWEB)

    Pompili, Maurizio, E-mail: mpompili@rm.unicatt.i [Department of Internal Medicine, Universita Cattolica del Sacro Cuore, Largo A. Gemelli, 8, 00168 Roma (Italy); Pacella, Claudio Maurizio, E-mail: claudiomauriziopacella@gmail.co [Department of Diagnostic Imaging and Interventional Radiology, Ospedale Regina Apostolorum, Via S. Francesco D' Assisi, 50, 00041 Albano Laziale (RM) (Italy); Francica, Giampiero, E-mail: giampierofrancica@tin.i [Department of Interventional Ultrasound, Presidio Ospedaliero Camilliani, S. Maria della Pieta, Via S. Rocco, 9, 80026 Casoria (Namibia) (Italy); Angelico, Mario, E-mail: angelico@med.uniroma2.i [Hepatology Unit, Universita di Tor Vergata, Viale Oxford, 81, 00133 Rome (Italy); Tisone, Giuseppe, E-mail: tisone@med.uniroma2.i [Transplant and General Surgery Unit, Universita di Tor Vergata, Ospedale S. Eugenio, Piazzale dell' Umanesimo 10-00144 Rome (Italy); Craboledda, Paolo, E-mail: paolo.craboledda@virgilio.i [Department of Pathology, Ospedale S. Eugenio, Piazzale dell' Umanesimo, 10-00144 Rome (Italy); Nicolardi, Erica; Rapaccini, Gian Ludovico; Gasbarrini, Giovanni [Department of Internal Medicine, Universita Cattolica del Sacro Cuore, Largo A. Gemelli, 8, 00168 Roma (Italy)

    2010-06-15

    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.

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

    International Nuclear Information System (INIS)

    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.

  9. Remote Magnetic Navigation: A Focus on Catheter Ablation of Ventricular Arrhythmias.

    Science.gov (United States)

    Aagaard, Philip; Natale, Andrea; Briceno, David; Nakagawa, Hiroshi; Mohanty, Sanghamitra; Gianni, Carola; Burkhardt, J David; DI Biase, Luigi

    2016-03-01

    VT ablation is based on percutaneous catheter insertion under fluoroscopic guidance to selectively destroy (i.e., ablate) myocardial tissue regions responsible for the initiation or propagation of ventricular arrhythmias. Although the last decade has witnessed a rapid evolution of ablation equipment and techniques, the control over catheter movement during manual ablation has remained largely unchanged. Moreover, the procedures are long, and require ergonomically unfavorable positions, which can lead to operator fatigue. In an attempt to overcome these constraints, several technical advancements, including remote magnetic navigation (RMN), have been developed. RMN utilizes a magnetic field to remotely manipulate specially designed soft-tip ablation catheters anywhere in the x, y, or z plane inside the patient's chest. RMN also facilitates titration of the contact force between the catheter and the myocardial tissue, which may reduce the risk of complications while ensuring adequate lesion formation. There are several non-randomized studies showing that RMN has similar efficacy to manual ablation, while complication rates and total radiation exposure appears to be lower. Although these data are promising, larger randomized studies are needed to prove that RMN is superior to manual ablation of VT.

  10. Modern Advances in Ablative TPS

    Science.gov (United States)

    Venkatapathy, Ethiraj

    2013-01-01

    Topics covered include: Physics of Hypersonic Flow and TPS Considerations. Destinations, Missions and Requirements. State of the Art Thermal Protection Systems Capabilities. Modern Advances in Ablative TPS. Entry Systems Concepts. Flexible TPS for Hypersonic Inflatable Aerodynamic Decelerators. Conformal TPS for Rigid Aeroshell. 3-D Woven TPS for Extreme Entry Environment. Multi-functional Carbon Fabric for Mechanically Deployable.

  11. A numerical simulation of ablation controlled arcs

    Energy Technology Data Exchange (ETDEWEB)

    Godin, D.; Trepanier, J.Y. [Ecole Polytechnique, Dept. of Mechanical Engineering, Montreal, PQ (Canada); Eby, S.D. [Ecole Polytechnique, Centre de Recherche en Calcul Applique, Montreal, PQ (Canada); Robin-Jouan, P. [GEC-Alsthom T and D, Villeurbanne, (France)

    1998-09-01

    An approach to model the ablation phenomenon of ablation controlled arcs using computational fluid dynamics was presented. Ablation controlled arcs are found in high voltage electrical equipment such as fuses and circuit-breakers. A qualitative prediction of the ablation level is critical from an industrial point of view because deliberate use of ablation is made to increase the pressure in a circuit-breaker chamber to allow for an efficient extinction when the current returns to zero. The numerical model was validated by comparing results of published experimental data. 7 refs., 10 figs.

  12. 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. PMID:27174311

  13. Investigation of radiation streaming and maze design for the Taiwan Photon Source.

    Science.gov (United States)

    Sheu, Rong-Jiun; Liu, Joseph

    2010-04-01

    This study investigates the radiation streaming through the personnel access maze designed for the Taiwan Photon Source, with special interest in the characteristics of radiation fields along the labyrinth and the comparison of different estimation methods. The effect of maze orientation with respect to the beam direction has also been examined in detail. The FLUKA Monte Carlo code was used to simulate the radiation production and transport for a beam loss occurring near a typical three-legged maze. In addition, we have also tested three factorized approximation formulae for the neutron and gamma-ray attenuation in our maze design. It was found that Cossairt's expression fits better and can predict satisfactory results for the neutron attenuation along the maze. We accordingly proposed a set of fitting parameters used with Cossairt's formulae for estimating the gamma-ray attenuation in labyrinths for high-energy electron accelerators. The information presented here will be valuable for our further design revisions and may be useful to those performing similar studies. PMID:20220363

  14. 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.

  15. Acute high dose of chlorpyrifos alters performance of rats in the elevated plus-maze and the elevated T-maze.

    Science.gov (United States)

    López-Crespo, G A; Flores, P; Sánchez-Santed, F; Sánchez-Amate, M C

    2009-11-01

    Chlorpyrifos (CPF) is a broad spectrum organophosphate (OP) pesticide widely used in agriculture, industry and household. Several animal studies indicate emotional disturbances after CPF exposure, although the results are sometimes puzzling. Thus, both anxiolytic and anxiogenic effects of CPF have been reported in different animal models of anxiety [Sánchez-Amate MC, Flores P, Sánchez-Santed F. Effects of chlorpyrifos in the plus-maze model of anxiety. Behav Pharmacol 2001;12:285-92; Sánchez-Amate MC, Dávila E, Cañadas F, Flores P, Sánchez-Santed F. Chlorpyrifos shares stimulus properties with pentilenetetrazol as evaluated by and operant drug discrimination task. Neurotoxicology 2002;23:795-803; López-Crespo G, Carvajal F, Flores P, Sánchez-Santed F, Sánchez-Amate MC. Time-course of biochemical and behavioural effects of a single high dose of chlorpyrifos. Neurotoxicology 2007;28:541-7]. On the other hand, other behavioural effects of CPF are time-dependent [López-Crespo G, Carvajal F, Flores P, Sánchez-Santed F, Sánchez-Amate MC. Time-course of biochemical and behavioural effects of a single high dose of chlorpyrifos. Neurotoxicology 2007;28:541-7], raising the question that the effects of CPF could be task and post-administration time dependent. To test this hypothesis, three groups of rats were treated with a single high dose of CPF (250 mg/kg); one of the groups was tested on day 5 on the elevated plus-maze, to complete our previous study on day 2 [Sánchez-Amate MC, Flores P, Sánchez-Santed F. Effects of chlorpyrifos in the plus-maze model of anxiety. Behav Pharmacol 2001;12:285-92]. The remaining groups were tested on the elevated T-maze on days 2 and 5. CPF produced an increased open arm activity on the elevated plus-maze on day 5, an increased escape latency on the elevated T-maze on day 2 and an impaired inhibitory avoidance on day 5. Data are discussed taking together all studies carried out in our laboratory, confirming that CPF effects on

  16. Radiofrequency ablation of osteoid osteoma: initial experience with a new monopolar ablation device.

    Science.gov (United States)

    Mahnken, Andreas H; Bruners, Philipp; Delbrück, Heide; Günther, Rolf W

    2011-06-01

    The purpose of this article is to report our initial experience with the "off-label" use of a new monopolar radiofrequency (RF) probe for percutaneous ablation of osteoid osteomas. Seventeen patients (12 male and 5 female, mean age 24.8 [range 9-49]) with osteoid osteoma were treated by computed tomography (CT)-guided RF ablation (RFA). All procedures were performed with the patient under general aesthesia. After localization of the nidus, a 13G hollow drill was introduced into the nidus through a 7F introducer sheath. A monopolar 16.5G RF probe with a 9-mm active tip (Soloist; Boston Scientific, Natick, MA) was inserted through the introducer sheath and connected to the RF generator. Energy application was started at 2 W and subsequently increased every 2 min by 1 W to a maximum of 8 W. The procedure ended if impedance increased by 500 Ω. Mean duration of energy deposition was 14.2±3.3 min. Fourteen of 17 patients (82%) were free of symptoms at 29.9±14.8 (range 4 to 47) months of follow-up. The primary and secondary success rates were 83% and 100%, respectively. In 3 patients, recurrence of pain at 6 (n=1) and 15 (n=2) months after the initial procedure was successfully treated by reablation. There were no complications. Monopolar RFA using the Soloist probe is effective and safe for the treatment of osteoid osteoma. It results in comparable success rates as other monopolar or bipolar RF systems in the treatment of osteoid osteoma. PMID:20490491

  17. Ablation of premature ventricular complexes exclusively guided by three-dimensional noninvasive mapping.

    Science.gov (United States)

    Erkapic, Damir; Neumann, Thomas

    2015-03-01

    Preprocedural detailed characterization of premature ventricular complexes before ablation, currently limited to the 12-lead electrocardiogram, may aid in planning and improve procedural outcomes. This article summarizes current published data on feasibility, accuracy, and impact on clinical outcomes of a novel, three-dimensional, noninvasive, single-beat mapping system (ECVUE, CardioInsight). ECVUE technology offers premature ventricular complex characterization and localization with clinically relevant accuracy and performance superior to the surface electrocardiogram. With its noninvasive and single beat advantages, ECVUE has the potential to simplify mapping, and reduce ablation and procedural time.

  18. Real-time spectroscopic assessment of thermal damage: implications for radiofrequency ablation.

    Science.gov (United States)

    Anderson, Christopher D; Lin, Wei-Chiang; Buttemere, Clay R; Washington, M Kay; Mahadevan-Jansen, Anita; Pierce, Janene; Nicoud, Ian B; Pinson, C Wright; Chari, Ravi S

    2004-01-01

    Radiofrequency ablation (RFA) is an evolving technology used to treat unresectable liver tumors. Currently, there is no accurate method to determine RFA margins in real-time during the procedure. We hypothesized that a fiber-optic based spectroscopic monitoring system could detect thermal damage from RFA in real-time. Fluorescence (F) and diffuse reflectance (Rd) spectra were continuously acquired from within the expected ablation zone during canine hepatic RFA using a fiber-optic microinterrogation probe (MIP). The F and Rd spectral feedback were continuously monitored and ablations were stopped based on changes in spectra alone. After each ablation, the MIP tract was marked with India ink and the ablation zone was excised. The relationship of the MIP to the zone of ablation was examined grossly and microscopically. F and Rd spectral changes occurred in three characteristic phases as the ablation zone progresses past the MIP. Phase 1 indicates minimal deviation from normal lives. Phase 2 occurs as the MIP lies within the hemorrhagic zone of the ablated tissue. Phase 3 correlates with complete tissue coagulation. The absolute magnitude of spectral change correlates with the gross and histologic degree of thermal damage. Optical spectroscopy is a technology that allows real-time detection of thermal tissue damage. In this study, both F and Rd spectroscopy accurately defined the advancing hemorrhagic edge of the zone of ablation and the central coagulation zone. These results suggest that F and Rd spectroscopy can be used to create a real-time feedback system to accurately define RFA margins. PMID:15358325

  19. Treatment of bone tumours by radiofrequency thermal ablation.

    Science.gov (United States)

    Santiago, Fernando Ruiz; Del Mar Castellano García, María; Montes, Jose Luis Martínez; García, Manuel Ruiz; Fernández, Juan Miguel Tristán

    2009-03-01

    Radiofrequency thermal ablation (RFTA) is considered the treatment of choice for osteoid osteomas, in which it has long been safely used. Other benign conditions (chondroblastoma, osteoblastoma, giant cell tumour, etc.) can also be treated by this technique, which is less invasive than traditional surgical procedures. RFTA ablation is also an option for the palliation of localized, painful osteolytic metastatic and myeloma lesions. The reduction in pain improves the quality of life of patients with cancer, who often have multiple morbidities and a limited life expectancy. In some cases, these patients are treated with RFTA because conventional therapies (surgery, radiotherapy, chemotherapy, etc.) have been exhausted. In other cases, it is combined with conventional therapies or other percutaneous treatments, e.g., cementoplasty, offering faster pain relief and bone strengthening. A multidisciplinary approach to the management of these patients is recommended to select the optimal treatment, including orthopaedic surgeons, neurosurgeons, medical and radiation oncologists and interventional radiologists. PMID:19468917

  20. Ablation dynamics in laser sclerotomy ab externo

    Science.gov (United States)

    Brinkmann, Ralf; Droege, Gerit; Mohrenstecher, Dirk; Scheu, M.; Birngruber, Reginald

    1996-01-01

    Laser sclerostomy ab externo with flashlamp excited mid-IR laser systems emitting in the 2-3 micrometer spectral range is in phase II clinical trials. Although acutely high success rates were achieved, the restenosis rate after several months is about 40%. Laser pulses of several hundreds of microseconds, known to induce thermo-mechanical explosive evaporation were used for this procedure. We investigated the ablation dynamics in tissue and the cavitation bubble dynamics in water by means of an Er:YAG laser system to estimate the extent of mechanical damage zones in the sclera and in the anterior chamber, which may contribute to the clinical failure. We found substantial mechanical tissue deformation during the ablation process caused by the cavitation effects. Stress waves up to several bar generated by explosive evaporization were measured. The fast mechanical stretching and collapsing of the scleral tissue induced by cavitation resulted in tissue dissection as could be proved by flash photography and histology. The observed high restenosis might be a result of a subsequent enhanced wound healing process. Early fistula occlusions due to iris adherences, observed in about 20% of the clinical cases may be attributed to intraocular trauma induced by vapor bubble expansion through the anterior chamber after scleral perforation. An automatic feedback system minimizing adverse effects by steering and terminating the laser process during scleral fistulization is demonstrated. Moreover, a new approach in laser sclerostomy ab externo is presented using a cw-IR laser diode system emitting at the 1.94 micrometer mid-IR water absorption peak. This system was used in vitro and showed smaller damage zones compared to the pulsed laser radiation.

  1. A cold radial maze for long-lasting spatial memory in mice.

    Science.gov (United States)

    Vizi, Sándor; Mansuy, Isabelle M

    2013-03-15

    Here we report the establishment of a novel spatial learning and memory test called the cold radial maze. It is specifically designed for mice, with all conditions tailored to their natural behaviors. The cold radial maze is a dry-land test with easy-to-measure variables that relies on a consistent motivation system and limits the moderately adverse experience to the duration of testing. Training on this maze produces a long-lasting, resistant, and reversible spatial memory in mice in a reproducible way, without introducing undesirable side effects typically produced in other spatial learning tests. This novel behavioral technique may prove useful in studying mouse models of memory impairment-associated human conditions.

  2. Palliative Procedures in Lung Cancer

    OpenAIRE

    Masuda, Emi; Sista, Akhilesh K.; Pua, Bradley B.; Madoff, David C.

    2013-01-01

    Palliative care aims to optimize comfort and function when cure is not possible. Image-guided interventions for palliative treatment of lung cancer is aimed at local control of advanced disease in the affected lung, adjacent mediastinal structures, or distant metastatic sites. These procedures include endovascular therapy for superior vena cava syndrome, bronchial artery embolization for hemoptysis associated with lung cancer, and ablation of osseous metastasis. Pathophysiology, clinical pres...

  3. Atrial fibrillation radiofrequency ablation: safety using contact force catheter in a low-volume centre

    Directory of Open Access Journals (Sweden)

    Diego Vaccari, MD; Daniele Giacopelli, MSc; Eros Rocchetto, MSc; Sabina Vittadello, MD; Roberto Mantovan, MD; Gianfilippo Neri, MD

    2014-08-01

    Full Text Available The tip-to-tissue contact force (CF has been identified as a potential determinant of lesion quality during radiofrequency (RF ablation. The aim of this paper is to report the experience of a single low-volume centre in the atrial fibrillation (AF ablation procedure with an RF catheter capable of measuring this parameter. CF data and their possible implications on patient safety are presented. Thirty-nine consecutive patients suffering of paroxysmal or permanent AF received percutaneous ablation with the novel catheter studied. Procedural characteristics, CF applied and safety events related to the procedure were reported. During RF application the mean CF value was 17 ± 3 g, with a maximum mean value of 37 ± 8 g. CF value never exceeds 62 g and in the 74% of the RF applications ranged between 10 g and 30 g. No complication related to the catheter manipulation or to the energy delivered was observed. This study of a single centre with a low level of experience in AF ablation suggests that the ability to measure CF may provide additional useful information to the operator. It ensures uniform ablations, with little variability in the catheter manipulations, and it avoids excessive contact forces increasing the patient safety.

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

    Science.gov (United States)

    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.

  5. Tumor Ablation with Irreversible Electroporation

    OpenAIRE

    Al-Sakere, Bassim; André, Franck,; Bernat, Claire; Connault, Elisabeth; Opolon, Paule; Davalos, Rafael V.; Rubinsky, Boris; Mir, Lluis M.

    2007-01-01

    We report the first successful use of irreversible electroporation for the minimally invasive treatment of aggressive cutaneous tumors implanted in mice. Irreversible electroporation is a newly developed non-thermal tissue ablation technique in which certain short duration electrical fields are used to permanently permeabilize the cell membrane, presumably through the formation of nanoscale defects in the cell membrane. Mathematical models of the electrical and thermal fields that develop dur...

  6. Caries selective ablation: the handpiece

    Science.gov (United States)

    Hennig, Thomas; Rechmann, Peter; Holtermann, Andreas

    1995-05-01

    Caries selective ablation is fixed to a window of fluences predicted by the ablation thresholds of carious and healthy dentin, respectively. The aim of the study was to develop a dental handpiece which guarantees homogeneous fluence at the irradiated tooth surface. Furthermore the point of treatment should be cooled down without energy losses due to the cooling system. We suggest the direct coupling of the laser radiation into a laminar stream of liquid, which acts in turn as a lengthened beam guide. The impacts of the laser radiation and of the cooling medium fall exactly into the same point. Hot ablation debris is removed out of the crater by the flush of the water jet. Fluences are constant if the handpiece is used in contact mode or at a distance. Normally the surface of a bare fiber working in contact mode is destroyed after a few shots. Coupling the laser radiation into a stream of liquid prevents this destruction. Putting together the benefits of this special handpiece short overall treatment times seem to be possible. High average power can be applied to the tooth without the threat of thermal damage. Furthermore no time consuming cutting of the fiber prolongs the treatment time.

  7. Effects of 5-HT1A receptor agonists and NMDA receptor antagonists in the social interaction test and the elevated plus maze.

    Science.gov (United States)

    Dunn, R W; Corbett, R; Fielding, S

    1989-10-01

    The effects of several 5-HT1A agonists and excitatory amino acid antagonists were compared to the standard benzodiazepines, diazepam and chlordiazepoxide (CDP) in two assays predictive of anxiolytic activity, the social interaction and elevated plus maze procedures. Indicative of anxiolytic effects the 5-HT1A agonists, buspirone, gepirone and 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) all significantly increased social interaction time and open arm exploration time in the social interaction and elevated plus maze procedures, respectively. Likewise, anxiolytic activity in these assays were also produced by the competitive N-methyl-D-aspartate (NMDA) antagonists, 2-amino-5-phosphonovaleric acid (AP-5), 2-amino-7-phosphonoheptanoic acid (AP-7), 3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP) and the non-competitive NMDA antagonist, (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine (MK-801) while NMDA produced anxiogenic effects. Furthermore, the anxiolytic effects of these agents were of equal magnitude to the benzodiazepines. These two classes of compounds were differentiated in the yohimbine-induced seizure assay, with the NMDA antagonists dose dependently antagonizing seizures similar to the benzodiazepines while the 5-HT1A agonists were inactive. These results suggest that the 5-HT1A agonists and the NMDA antagonists may be potential non-classical anxiolytic agents with different mechanisms of action.

  8. Explosive character of the atheroma plaques ablation

    International Nuclear Information System (INIS)

    At the present time, ischemia (heart disease) is a main cause of the death in the world; a promising method for its treatment is the use of the technology of the laser light of raised power for the ablation of the atherosclerosis plaques. In this paper, the thermodynamic processes will be studied at the beginning and during atheroma ablation using Nd-YAG (10-50 w) and Argon (4-10 w) lasers of a theoretical point of view. The spatial distribution of the temperature during the ablation has been modelated by the method of finite volumes. The manifestation of the raised temperature of the tissue at the threshold of the ablation, which describes the explosive nature of the ablation by laser (popcorn effect), is observed and discussed. The results indicate the quantitative differences in the ablation behavior between the two used lasers, which can have important clinical implications particularly in the reduction of thermal damages to surrounding normal tissue. (author)

  9. Transient Ablation Regime in Circuit Breakers

    Institute of Scientific and Technical Information of China (English)

    Alexandre MARTIN; Jean-Yves TREPANIER; Marcelo REGGIO; GUO Xue-yan

    2007-01-01

    Nozzle wall ablation caused by high temperature electric arcs is studied in the context of high voltage SF6 circuit breakers.The simplified ablation model used in litterature has been updated to take into account the unsteady state of ablation.Ablation rate and velocity are now calculated by a kinetic model using two layers of transition,between the bulk plasma and the ablating wall.The first layer (Knudsen layer),right by the wall,is a kinetic layer of a few mean-free path of thickness.The second layer is collision dominated and makes the transition between the kinetic layer and the plasma bulk.With this new coupled algorithm,it is now possible to calculate the temperature distribution inside the wall,as well as more accurate ablation rates.

  10. Ablation and carbon deposition induced by UV laser irradiation of polyimide: Application to the metallization of VIAs in high density printed circuit boards

    International Nuclear Information System (INIS)

    Polyimides are known to exhibit large ablation rates upon irradiation with excimer laser due to their high absorbance in the UV and low fluorescence yield. We have studied different regimes of laser ablation according to the fluence and studied the structures resulting from carbon products deposition. For fluences larger than the polyimide ablation threshold, but lower than the carbon one, the development of one structure is the dominant process, whereas large ablation rates lead to polyimide etching above the carbon ablation threshold. The deposition of a carbon layer on the walls of ablated slits has in particular been investigated using an original experimental technique. Optical microscopy and MEB have shown that this carbon layer covered the main height of the ablated holes whereas a threshold (bare polyimide) for carbon condensation was evidenced at the bottom of the ablated hole. Raman spectroscopy and conductivity measurements have shown that the carbon phase is mainly graphitic. A dependence of the carbon condensation threshold on the slit width has been evidenced and discussed in relation with the angle of ejection of ablation debris. A procedure has been developed to render the bare polyimide of the threshold region conductive. At last the conductive properties of the walls of the ablated holes have been exploited to perform an electrolytic metallization. Implications for the production of interconnection vertical interconnections (VIAs) in high density printed circuits are addressed

  11. Computer-aided hepatic tumour ablation

    CERN Document Server

    Voirin, D; Amavizca, M; Leroy, A; Letoublon, C; Troccaz, J; Voirin, David; Payan, Yohan; Amavizca, Miriam; Leroy, Antoine; Letoublon, Christian; Troccaz, Jocelyne

    2001-01-01

    Surgical resection of hepatic tumours is not always possible. Alternative techniques consist in locally using chemical or physical agents to destroy the tumour and this may be performed percutaneously. It requires a precise localisation of the tumour placement during ablation. Computer-assisted surgery tools may be used in conjunction to these new ablation techniques to improve the therapeutic efficiency whilst benefiting from minimal invasiveness. This communication introduces the principles of a system for computer-assisted hepatic tumour ablation.

  12. Role of Cardiac Imaging (CT/MR Before and After RF Catheter Ablation in Patients with Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Aravindan Kolandaivelu, MD

    2012-08-01

    Full Text Available Pre-procedure X-ray computed tomography (CT and magnetic resonance imaging (MRI angiography are commonly used to delineate the complex and variable relationship of the left atrium, pulmonary veins, and surrounding structures. 3D CT and MR angiography are routinely incorporated into electroanatomic mapping systems to guide ablation lesion placement in the context of patient specific anatomy. Post-procedure CT and MRI have also proven useful for evaluating complications such as pulmonary vein stenosis. In the future, these imaging modalities may be used to visualize more detailed tissue characteristics such as atrial fibrosis and ablation lesions. This could improve selection of patients for different treatment strategies and perhaps guide more effective ablation. This review will discuss current and emerging applications of CT and MRI before and after radiofrequency catheter ablation of atrial fibrillation.

  13. Biatrial ablation versus left atrial ablation with bipolar system in the surgical treatment of atrial fibrillation with mitral valve disease%二尖瓣手术同期双心房与左心房心房颤动射频消融效果对比

    Institute of Scientific and Technical Information of China (English)

    姜兆磊; 梅举; 丁芳宝; 徐方杰; 马南; 沈赛娥; 汤敏; 尹航

    2014-01-01

    Objective The purpose of this study was to compare the outcome after biatrial ablation or left atrial ablation in patients with atrial fibrillation(AF) associated with mitral valve diseases.Methods All 109 patients who received biatrial ablation (n =61) or left atrial ablation (n =48) of atrial fibrillation combined with mitral valve surgery from January 2008 to December 2012 were analyzed for outcome differences.The etiology of mitral valve disease was rheumatic(n =81) and degenerative(n =28).Age at operation ranged from 39 to 62 years.AF duration ranged from 7 months to 13 years.Clinical manifestations of atrial fibrillation were persistent in 34 patiens and long-standing persistent in 75 patients.Results All patients successfully underwent radiofrequency modified maze procedure and mitral valve surgery.The biatrial ablation group had longer cardiopulmonary bypass time and crossclamp time.But there was no significant difference in mechanical ventilation,hospital length of stay and major postoperative complications or other postoperative outcome variables between biatrial ablation and lefi atrial ablation groups.There was 1 early death in left arial ablation group.At postoperative moment,the elimination rate of atrial fibril lation were 100% (sinus rhythm in 94 and junctional rhythm in 15).At discharge,maintenance of normal sinus rhythm was 93.4% in biatrial group and 80.9% in left atrial group (P =0.046).Cumulative maintenance of normal sinus rhythm without atrial fibrillation recurrence at 3 years postoperatively was (89.0 ± 4.4) % in biatrial group and (75.6 ± 7.3) % in left atrial group,P =0.096.But the incidence of atrial flutter at 1 year postoperatively in left atrial group(10.6%) was significantly higher than the biatrial group (0),P =0.032.Conclusion Compared with left atrial ablation,biatrial ablation was more effective in restoration and maintenance of sinus rhythm without increasing the risk of postoperative complications.In addition

  14. Aromatic Thermosetting Copolyesters for Ablative TPS Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Better performing ablative thermal protection systems than currently available are needed to satisfy requirements of the most severe crew exploration vehicles, such...

  15. A robust animal model of state anxiety: fear-potentiated behaviour in the elevated plus-maze

    NARCIS (Netherlands)

    Korte, S.M.; Boer, de S.F.

    2003-01-01

    Fear (i.e., decreased percentage time spent on open-arm exploration) in the elevated plus-maze can be potentiated by prior inescapable stressor exposure, but not by escapable stress. The use of fear-potentiated plus-maze behaviour has several advantages as compared to more traditional animal models

  16. Variance in Broad Reading Accounted for by Measures of Reading Speed Embedded within Maze and Comprehension Rate Measures

    Science.gov (United States)

    Hale, Andrea D.; Skinner, Christopher H.; Wilhoit, Brian; Ciancio, Dennis; Morrow, Jennifer A.

    2012-01-01

    Maze and reading comprehension rate measures are calculated by using measures of reading speed and measures of accuracy (i.e., correctly selected words or answers). In sixth- and seventh-grade samples, we found that the measures of reading speed embedded within our Maze measures accounted for 50% and 39% of broad reading score (BRS) variance,…

  17. A robust animal model of state anxiety : fear-potentiated behaviour in the elevated plus-maze

    NARCIS (Netherlands)

    Korte, SM; De Boer, SF

    2003-01-01

    Fear (i.e., decreased percentage time spent on open-arm exploration) in the elevated plus-maze can be potentiated by prior inescapable stressor exposure, but not by escapable stress. The use of fear-potentiated plus-maze behaviour has several advantages as compared to more traditional animal models

  18. 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.

  19. Laser ablation for small hepatocellular carcinoma: State of the art and future perspectives

    Institute of Scientific and Technical Information of China (English)

    Giovan; Giuseppe; Di; Costanzo; Giampiero; Francica; Claudio; Maurizio; Pacella

    2014-01-01

    During the last two decades, various local thermal ablative techniques for the treatment of unresectable hepatocellular carcinoma(HCC) have been developed. According to internationally endorsed guidelines, percutaneous thermal ablation is the mainstay of treatment in patients with small HCC who are not candidates for surgical resection or transplantation. Laser ablation(LA) represents one of currently available loco-ablative techniques. In this article, the general principles, technique, image guidance, and patient selection are reported. Primary effectiveness, long-term outcome, and complications are also discussed. A review of published data suggests that LA is equivalent to the more popular and widespread radiofrequency ablation in both local tumor control and long-term outcome in the percutaneous treatment of early HCC. In addition, the LA technique using multiple thin laser fibres allows improved ablative effectiveness in HCCs greater than 3 cm. Reference centres should be equipped with all the available techniques so as to be able to use the best and the most suitable procedure for each type of lesion for each patient.

  20. Terminology and Reporting Criteria for Radiofrequency Ablation of Tumors in the Scientific Literature: Systematic Review of Compliance with Reporting Standards

    OpenAIRE

    Kang, Tae Wook; Rhim, Hyunchul; Lee, Min Woo; Kim, Young-sun; Choi, Dongil; Lim, Hyo Keun

    2014-01-01

    Objective To perform a systematic review of compliance with standardized terminology and reporting criteria for radiofrequency (RF) tumor ablation, proposed by the International Working Group on Image-Guided Tumor Ablation in 2003, in the published reports. Materials and Methods Literature search in the PubMed database was performed using index keywords, PubMed limit system, and eligibility criteria. The entire content of each article was reviewed to assess the terminology used for procedure ...

  1. Radial Maze Analog for Pigeons: Evidence for Flexible Coding Strategies May Result from Faulty Assumptions

    Science.gov (United States)

    Gipson, Cassandra D.; DiGian, Kelly A.; Miller, Holly C.; Zentall, Thomas R.

    2008-01-01

    Previous research with the radial maze has found evidence that rats can remember both places that they have already been (retrospective coding) and places they have yet to visit (prospective coding; Cook, R. G., Brown, M. F., & Riley, D. A. (1985). Flexible memory processing by rats: Use of prospective and retrospective information in the radial…

  2. Incremental Sentence Processing in Japanese: A Maze Investigation into Scrambled and Control Sentences

    Science.gov (United States)

    Witzel, Jeffrey; Witzel, Naoko

    2016-01-01

    This study investigates preverbal structural and semantic processing in Japanese, a head-final language, using the maze task. Two sentence types were tested--simple scrambled sentences (Experiment 1) and control sentences (Experiment 2). Experiment 1 showed that even for simple, mono-clausal Japanese sentences, (1) there are online processing…

  3. 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

    2012-06-01

    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.

  4. Optimization of Catheter Ablation of Atrial Fibrillation: Insights Gained from Clinically-Derived Computer Models

    Directory of Open Access Journals (Sweden)

    Jichao Zhao

    2015-05-01

    Full Text Available Atrial fibrillation (AF is the most common heart rhythm disturbance, and its treatment is an increasing economic burden on the health care system. Despite recent intense clinical, experimental and basic research activity, the treatment of AF with current antiarrhythmic drugs and catheter/surgical therapies remains limited. Radiofrequency catheter ablation (RFCA is widely used to treat patients with AF. Current clinical ablation strategies are largely based on atrial anatomy and/or substrate detected using different approaches, and they vary from one clinical center to another. The nature of clinical ablation leads to ambiguity regarding the optimal patient personalization of the therapy partly due to the fact that each empirical configuration of ablation lines made in a patient is irreversible during one ablation procedure. To investigate optimized ablation lesion line sets, in silico experimentation is an ideal solution. 3D computer models give us a unique advantage to plan and assess the effectiveness of different ablation strategies before and during RFCA. Reliability of in silico assessment is ensured by inclusion of accurate 3D atrial geometry, realistic fiber orientation, accurate fibrosis distribution and cellular kinetics; however, most of this detailed information in the current computer models is extrapolated from animal models and not from the human heart. The predictive power of computer models will increase as they are validated with human experimental and clinical data. To make the most from a computer model, one needs to develop 3D computer models based on the same functionally and structurally mapped intact human atria with high spatial resolution. The purpose of this review paper is to summarize recent developments in clinically-derived computer models and the clinical insights they provide for catheter ablation.

  5. A questionable indication for ICD extraction after successful VT ablation

    Directory of Open Access Journals (Sweden)

    Luca Segreti, MD; Andrea Di Cori, MD; Giulio Zucchelli, MD, PhD; Ezio Soldati, MD; Giovanni Coluccia, MD; Stefano Viani, MD; Luca Paperini, MD; Maria Grazia Bongiorni, MD, FESC

    2015-04-01

    Full Text Available Sustained ventricular tachyarrhythmias represent a kind of complication shared by a number of clinical presentations of heart disease, sometimes leading to sudden cardiac death. Many efforts have been made in the fight against such a complication, mainly being represented by the implantable cardioverter defibrillator (ICD. In recent years, catheter ablation has grown as a means to effectively treat patients with sustained ventricular arrhythmias, in the contest of different cardiac substrates. Since carrying an ICD is associated with a potential risk deriving from its possible infective or malfunctioning complications, and given the current effectiveness of lead extraction procedures, it has been thought not to be unreasonable to ask ourselves about how to deal with ICD patients who have been successfully treated by means of ablation of their ventricular arrhythmias. In this paper we will review the current evidence about ICD therapy, catheter ablation of ventricular arrhythmias and lead extraction, trying to outline some considerations about how to face this new clinical issue.

  6. Micropatterned polysaccharide surfaces via laser ablation for cell guidance

    Energy Technology Data Exchange (ETDEWEB)

    Barbucci, Rolando; Lamponi, Stefania; Pasqui, Daniela; Rossi, Antonella; Weber, Elisabetta

    2003-03-03

    Micropatterned materials were obtained by a controlled laser ablation of a photoimmobilised homogeneous layer of hyaluronic acid (Hyal) and its sulphated derivative (HyalS). The photoimmobilisation was performed by coating the polysaccharide, adequately functionalised with a photoreactive group, on aminosilanised glass substrate and immobilising it on the surface under UV light. Hyal or HyalS photoimmobilised samples were then subjected to laser ablation with wavelengths in the UV regions in order to drill the pattern. Four different patterns with stripes of 100, 50, 25 and 10 {mu}m were generated. A chemical characterisation by attenuated total reflection/Fourier transform infrared (ATR/FT-IR) and time of flight-secondary ions mass spectrometry (TOF-SIMS) confirmed the success of the laser ablation procedure and the presence of alternating stripes of polysaccharide and native glass. The exact dimensions of the stripes were determined by atomic force microscopy. The analysis of cell behaviour in terms of adhesion, proliferation and movement using mouse fibroblasts (3T3 line) and bovine aortic endothelial cells (BAEC) was also performed.

  7. Contact force assessment in catheter ablation of atrial fibrillatio

    Directory of Open Access Journals (Sweden)

    Josef Kautzner; Petr Peichl

    2014-04-01

    Full Text Available The efficacy of catheter ablation of atrial fibrillation (AF remains limited. Increase of success would require more durable lesions without increased risk of steam pop and cardiac perforation. Recently, novel technologies have been developed to estimate real-time catheter-tissue contact force (CF. This paper reviews three available tools for assessment of CF and data on experimental or clinical experience. Experimental data with open-irrigated catheter showed that lesion size was greater with applications of lower power (like 30 W and greater CF (e.g. 30 to 40 g than vice versa. Impedance drop in the first 5 seconds was significantly correlated to catheter CF. Perforation was achieved more rapidly with the ablation catheter in a sheath despite the same CF because the sheath prevents catheter buckling. Clinical experience confirmed poor relationship between CF and either unipolar amplitude, bipolar amplitude, or impedance. Within the left atrium, the most common high CF site was found at the anterior/rightward LA roof, directly beneath the ascending aorta (confirmed by merging the CT image and map. Importantly, several studies showed that the use of CF leads to shorter procedure with less fluoroscopy time and less RF applications. CF assessment was also found to be associated with higher proportion of durable lesions. Finally, pilot studies showed that CF measurement could be associated with better clinical efficacy AF ablation.

  8. Role of Optical Coherence Tomography on Corneal Surface Laser Ablation

    Directory of Open Access Journals (Sweden)

    Bruna V. Ventura

    2012-01-01

    Full Text Available This paper focuses on reviewing the roles of optical coherence tomography (OCT on corneal surface laser ablation procedures. OCT is an optical imaging modality that uses low-coherence interferometry to provide noninvasive cross-sectional imaging of tissue microstructure in vivo. There are two types of OCTs, each with transverse and axial spatial resolutions of a few micrometers: the time-domain and the fourier-domain OCTs. Both have been increasingly used by refractive surgeons and have specific advantages. Which of the current imaging instruments is a better choice depends on the specific application. In laser in situ keratomileusis (LASIK and in excimer laser phototherapeutic keratectomy (PTK, OCT can be used to assess corneal characteristics and guide treatment decisions. OCT accurately measures central corneal thickness, evaluates the regularity of LASIK flaps, and quantifies flap and residual stromal bed thickness. When evaluating the ablation depth accuracy by subtracting preoperative from postoperative measurements, OCT pachymetry correlates well with laser ablation settings. In addition, OCT can be used to provide precise information on the morphology and depth of corneal pathologic abnormalities, such as corneal degenerations, dystrophies, and opacities, correlating with histopathologic findings.

  9. Epicardial Ventricular Tachycardia Ablation: Clinical Practice and Recent Developments

    Directory of Open Access Journals (Sweden)

    Michalis Efremidis MD

    2011-08-01

    Full Text Available Mapping and radiofrequency (RF catheter ablation of ventricular tachycardia (VT is a demanding procedure, with variable success rates (1. The presence of deep subendocardial or epicardial re-entry circuits is regarded as one of the reasons of failure of endocardial ablation, and these circuits have been acknowledged in ischemic and non-ischemic dilated cardiomyopathy (CMP, other types of CMP and especially in arrhythmogenic right ventricular cardiomyopathy (ARVC.The significance of epicardial VT circuits was brought to light in Chagas’ disease, which characteristically results in epicardial involvement in approximately 70% of patients (2. A recent study found one third of VTs to be epicardial in origin among patients with nonischemic CMP, about double the incidence among those with ischemic heart disease(3. Mapping and ablation of these epicardial circuits is quite exigent. Although coronary veins can be used to perform epicardial mapping, the manipulation of the catheter is strictly limited to the anatomical distribution of these vessels. Thus, the subxiphoid percutaneous approach to the pericardial space is the only technique that allows extensive, unhampered mapping of the epicardial surface of both ventricles.

  10. 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.

    2012-01-01

    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 perform

  11. Complications of atrial fibrillation ablation: when prevention is better than cure

    NARCIS (Netherlands)

    Sorgente, A.; Chierchia, G.B.; Asmundis, C. de; Sarkozy, A.; Capulzini, L.; Brugada, P.

    2011-01-01

    As atrial fibrillation ablation is becoming increasingly popular in many cardiac electrophysiological laboratories around the world, preventing, avoiding, or treating procedure-related complications is of utmost importance. In our review of the literature regarding this issue, we addressed in detail

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

    International Nuclear Information System (INIS)

    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)

  13. 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;

    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...

  14. Long-term clinical outcome after alcohol septal ablation for obstructive hypertrophic cardiomyopathy

    DEFF Research Database (Denmark)

    Veselka, Josef; Jensen, Morten Kvistholm; Liebregts, Max;

    2016-01-01

    AIMS: The first cases of alcohol septal ablation (ASA) for obstructive hypertrophic cardiomyopathy (HCM) were published two decades ago. Although the outcomes of single-centre and national ASA registries have been published, the long-term survival and clinical outcome of the procedure are still...

  15. Transcoronary ablation of septal hypertrophy compared with surgery in the treatment of hypertrophic obstructive cardiomyopathy

    Institute of Scientific and Technical Information of China (English)

    姜腾勇; 吴学思; 吕强; 孟旭; 贾长琪; 张银

    2004-01-01

    @@ Transcoronary ablation of septal hypertrophy (TASH)can lead to sustained improvement in both hemodynamics and symptoms in patients with hypertrophic obstructive cardiomyopathy ( HOCM ) . 1-4 However, there have been few reports about its efficacy and safety compared with traditional surgical procedures. This study sought to compare TASH with surgery in the treatment of HOCM.

  16. 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.

  17. Laser ablation studies of solid aerosols on the Baltic coast

    Directory of Open Access Journals (Sweden)

    Robert Jaworski

    2004-09-01

    Full Text Available A Berner cascade impactor was used for the separation of solid urban aerosols in two localities of the Baltic coastal macro-region - Słupsk and Hel - in different seasons and weathers. Ten ranges of aerodynamic diameters between 0.009 and 8.11 µm were used. The elementary composition for each diameter was obtained in a complex procedure consisting of laser ablation of deposits, then their successive ionization in an inductively coupled plasma generator, and finally, mass selection in a quadrupole spectrometer. Despite its complexity, the chemical element analysis method proved to be versatile, allowing the identification air pollution from natural and industrial sources, and road traffic.

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

    Energy Technology Data Exchange (ETDEWEB)

    Maurer, M.H., E-mail: martin.maurer@charite.de [Charite - Universitaetsmedizin Berlin, Department of Radiology, Augustenburger Platz 1, 13353 Berlin (Germany); Gebauer, B., E-mail: bernhard.gebauer@charite.de [Charite - Universitaetsmedizin Berlin, Department of Radiology, Augustenburger Platz 1, 13353 Berlin (Germany); Wieners, G., E-mail: gero.wieners@charite.de [Charite - Universitaetsmedizin Berlin, Department of Radiology, Augustenburger Platz 1, 13353 Berlin (Germany); De Bucourt, M., E-mail: maximilian.de-bucourt@charite.de [Charite - Universitaetsmedizin Berlin, Department of Radiology, Augustenburger Platz 1, 13353 Berlin (Germany); Renz, D.M., E-mail: diane.renz@charite.de [Charite - Universitaetsmedizin Berlin, Department of Radiology, Augustenburger Platz 1, 13353 Berlin (Germany); Hamm, B., E-mail: bernd.hamm@charite.de [Charite - Universitaetsmedizin Berlin, Department of Radiology, Augustenburger Platz 1, 13353 Berlin (Germany); Streitparth, F., E-mail: florian.streitparth@charite.de [Charite - Universitaetsmedizin Berlin, Department of Radiology, Augustenburger Platz 1, 13353 Berlin (Germany)

    2012-11-15

    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.

  19. Possible role for cryoballoon ablation of right atrial appendage tachycardia when conventional ablation fails.

    Science.gov (United States)

    Amasyali, Basri; Kilic, Ayhan

    2015-06-01

    Focal atrial tachycardia arising from the right atrial appendage usually responds well to radiofrequency ablation; however, successful ablation in this anatomic region can be challenging. Surgical excision of the right atrial appendage has sometimes been necessary to eliminate the tachycardia and prevent or reverse the resultant cardiomyopathy. We report the case of a 48-year-old man who had right atrial appendage tachycardia resistant to multiple attempts at ablation with use of conventional radiofrequency energy guided by means of a 3-dimensional mapping system. The condition led to cardiomyopathy in 3 months. The arrhythmia was successfully ablated with use of a 28-mm cryoballoon catheter that had originally been developed for catheter ablation of paroxysmal atrial fibrillation. To our knowledge, this is the first report of cryoballoon ablation without isolation of the right atrial appendage. It might also be an alternative to epicardial ablation or surgery when refractory atrial tachycardia originates from the right atrial appendage.

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

    Energy Technology Data Exchange (ETDEWEB)

    Krmar, M.; Kuzmanović, A. [Physics Department, Faculty of Science, University of Novi Sad, Novi Sad 21000 (Serbia); Nikolić, D. [National Institute for Nanotechnology, Edmonton, Alberta T6G 2M9 (Canada); Kuzmanović, Z. [International Medical Centers, Banja Luka 78000, Republika Srpska, Bosnia and Herzegovina (Bosnia and Herzegowina); Ganezer, K. [Physics Department, California State University Dominguez Hills, Carson, California 90747 (United States)

    2013-08-15

    Purpose: 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.Methods: 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.Results: 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.Conclusions: 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.

  1. Hyperkalaemia after radiofrequency ablation of hepatocellular carcinoma

    NARCIS (Netherlands)

    Verhoevena, BH; Haagsma, EB; Appeltans, BMG; Slooff, MJH; de Jong, KP

    2002-01-01

    Radiofrequency ablation of liver tumours is a useful therapy for otherwise unresectable tumours. The complication rate is said to be low. In this case report we describe hyperkalaemia after radiofrequency ablation of a hepatocellular carcinoma in a patient with end-stage renal insufficiency. (C) 200

  2. RADIOFREQUENCY ABLATION OF IDIOPATHIC RIGHT VENTRICULAR TACHYCARDIA

    Institute of Scientific and Technical Information of China (English)

    华伟; JituVohra

    1998-01-01

    This paper presents our experieaee with radioreqencey ablation (RFA) for idiopathic ventricular tschycardia (VT) arising from right ventricle in 12 patients(pts). The age range d patients was 21~50, with a mean of 38. 5 years. Ten out of 12 were females, 1 patient had eandia failure due to almost incessant VT while the rest had normal left ventricular function.Twelve pts had VT arising from the fight ventricle; of those, 9 were from the outflow truct, 2 from the RV apex, and l from the RV inflow. In all tats the diagnostic study and therapeutic RFA were combined in a single procedure, pacemapping and local aetlvition time were used to guide the site of RFA in Ors with VT arising froth the tight ventricle.RFA was successful in 11 of the 12 pts ( 91%). Ntmaher of RF applications were 1~27, mean 9. 6; fluoroscopy time were 4~75, mean 26. 9 minutes. RFA for idiopathic RV has a high success rate. This mode of treament should be considered as a nonphartaaeologieal curative treatment for symptomatic pts.

  3. Radiofrequency ablation for renal tumors. Our experience

    International Nuclear Information System (INIS)

    The objective of this study was to report our results of percutaneous radiofrequency ablation (RFA) for renal tumors and to assess predictors of therapeutic efficacy. Forty patients (median age 73 years) with renal tumors were treated with RFA under local or epidural anesthesia. All of them had high surgical risk or refused radical surgery. Tumors were punctured percutaneously using the Radionics Cool-tip RF System under computed tomography or ultrasonographic guidance. Median tumor diameter was 24 mm. After RFA, contrast-enhanced computed tomography or magnetic resonance imaging was performed within 1 month. Complete response (CR) was defined as no enhancement inside the tumor. Factors related to the outcome and to renal function were assessed. Median follow up was 16 months. CR was observed in 34 cases (85.0%). A significant difference in CR rate was observed between tumors ≤30 mm and those >30 mm. Outcomes tended to be better for tumors in the mid to lower kidney, and those away from the renal hilum. Recurrence was observed in one case (2.9%), but a CR was obtained again by additional RFA. Out of a total of 77 RFA procedures, complications occurred in only three cases (3.9%), and conservative treatment was possible in all cases. Serum creatinine levels 3 months after RFA did not differ from those before RFA. Percutaneous RFA is a safe and effective treatment for small renal tumors in patients with high surgical risk or who refuse radical surgery. (author)

  4. High Heat Flux Block Ablator-in-Honeycomb Heat Shield Using Ablator/Aerogel-Filled Foam Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Ultramet and ARA Ablatives Laboratory previously developed and demonstrated advanced foam-reinforced carbon/phenolic ablators that offer substantially increased...

  5. 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.

  6. Imaging Features of Radiofrequency Ablation with Heat-Deployed Liposomal Doxorubicin in Hepatic Tumors

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Cheng William, E-mail: williamhongcheng@gmail.com; Chow, Lucy, E-mail: lucychow282@gmail.com [National Institutes of Health, Center for Interventional Oncology, Clinical Center (United States); Turkbey, Evrim B., E-mail: evrimbengi@yahoo.com [National Institutes of Health, Radiology and Imaging Sciences, Clinical Center (United States); Lencioni, Riccardo, E-mail: riccardo.lencioni@med.unipi.it [Pisa University Hospital, Division of Diagnostic Imaging and Intervention, Department of Hepatology and Liver Transplantation (Italy); Libutti, Steven K., E-mail: slibutti@montefiore.org [Albert Einstein College of Medicine, Montefiore-Einstein Center for Cancer Care, Department of Surgery (United States); Wood, Bradford J., E-mail: bwood@nih.gov [National Institutes of Health, Center for Interventional Oncology, Clinical Center (United States)

    2016-03-15

    IntroductionThe imaging features of unresectable hepatic malignancies in patients who underwent radiofrequency ablation (RFA) in combination with lyso-thermosensitive liposomal doxorubicin (LTLD) were determined.Materials and MethodsA phase I dose escalation study combining RFA with LTLD was performed with peri- and post- procedural CT and MRI. Imaging features were analyzed and measured in terms of ablative zone size and surrounding penumbra size. The dynamic imaging appearance was described qualitatively immediately following the procedure and at 1-month follow-up. The control group receiving liver RFA without LTLD was compared to the study group in terms of imaging features and post-ablative zone size dynamics at follow-up.ResultsPost-treatment scans of hepatic lesions treated with RFA and LTLD have distinctive imaging characteristics when compared to those treated with RFA alone. The addition of LTLD resulted in a regular or smooth enhancing rim on T1W MRI which often correlated with increased attenuation on CT. The LTLD-treated ablation zones were stable or enlarged at follow-up four weeks later in 69 % of study subjects as opposed to conventional RFA where the ablation zone underwent involution compared to imaging acquired immediately after the procedure.ConclusionThe imaging features following RFA with LTLD were different from those after standard RFA and can mimic residual or recurrent tumor. Knowledge of the subtle findings between the two groups can help avoid misinterpretation and proper identification of treatment failure in this setting. Increased size of the LTLD-treated ablation zone after RFA suggests the ongoing drug-induced biological effects.

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

    Energy Technology Data Exchange (ETDEWEB)

    Rhim, Hyunchul; Kim, Young-sun; Choi, Dongil; Lim, Hyo K.; Park, KoWoon [Samsung Medical Center, Sungkyunkwan University School of Medicine, Department of Radiology and Center for Imaging Science, Seoul (Korea)

    2008-07-15

    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.)

  8. Imaging Features of Radiofrequency Ablation with Heat-Deployed Liposomal Doxorubicin in Hepatic Tumors

    International Nuclear Information System (INIS)

    IntroductionThe imaging features of unresectable hepatic malignancies in patients who underwent radiofrequency ablation (RFA) in combination with lyso-thermosensitive liposomal doxorubicin (LTLD) were determined.Materials and MethodsA phase I dose escalation study combining RFA with LTLD was performed with peri- and post- procedural CT and MRI. Imaging features were analyzed and measured in terms of ablative zone size and surrounding penumbra size. The dynamic imaging appearance was described qualitatively immediately following the procedure and at 1-month follow-up. The control group receiving liver RFA without LTLD was compared to the study group in terms of imaging features and post-ablative zone size dynamics at follow-up.ResultsPost-treatment scans of hepatic lesions treated with RFA and LTLD have distinctive imaging characteristics when compared to those treated with RFA alone. The addition of LTLD resulted in a regular or smooth enhancing rim on T1W MRI which often correlated with increased attenuation on CT. The LTLD-treated ablation zones were stable or enlarged at follow-up four weeks later in 69 % of study subjects as opposed to conventional RFA where the ablation zone underwent involution compared to imaging acquired immediately after the procedure.ConclusionThe imaging features following RFA with LTLD were different from those after standard RFA and can mimic residual or recurrent tumor. Knowledge of the subtle findings between the two groups can help avoid misinterpretation and proper identification of treatment failure in this setting. Increased size of the LTLD-treated ablation zone after RFA suggests the ongoing drug-induced biological effects

  9. Interventional procedures in the chest.

    Science.gov (United States)

    Vollmer Torrubiano, I; Sánchez González, M

    2016-05-01

    Many thoracic conditions will require an interventional procedure for diagnosis and/or treatment. For this reason, radiologists need to know the indications and the technique for each procedure. In this article, we review the various interventional procedures that radiologists should know and the indications for each procedure. We place special emphasis on the potential differences in the diagnostic results and complications between fine-needle aspiration and biopsy. We also discuss the indications for radiofrequency ablation of lung tumors and review the concepts related to the drainage of pulmonary abscesses. We devote special attention to the management of pleural effusion, covering the indications for thoracocentesis and when to use imaging guidance, and to the protocol for pleural drainage. We also discuss the indications for percutaneous treatment of pericardial effusion and the possible complications of this treatment. Finally, we discuss the interventional management of mediastinal lesions and provide practical advice about how to approach these lesions to avoid serious complications.

  10. Issues related to radioactive iodine ablation in patients with differentiated thyroid carcinoma undergoing thyroid surgery

    International Nuclear Information System (INIS)

    Differentiated thyroid carcinoma (DTC) is the most common malignant tumor of thyroid gland, including papillary thyroid carcinoma, follicular thyroid carcinoma and the mixed type. Treatment methods include surgery, radioactive iodine treatment and endocrine treatment, in which radioactive iodine treatment for thyroid carcinoma is an important part of the treatment or procedure. With the ongoing research and exploration of radiation treatment, the recombinant human thyroid stimulating hormone assisted in radioactive iodine ablation of thyroid remnants, radioactive iodine to remove a lot of residual thyroid tissue, the radioactive iodine dose selection and other aspects of knowledge and practice are constantly updated. This paper summarizes recent progess in the radioactive iodine ablation. (authors)

  11. History and Technical Approaches and Considerations for Ablative Surgery for Epilepsy.

    Science.gov (United States)

    Sinha, Saurabh; Danish, Shabbar F

    2016-01-01

    The history of epilepsy surgery is generally noted to have begun in 1886 with Victor Horsley's first report of craniotomies for posttraumatic epilepsy. With increased understanding of brain function and development of electroencephalographic methods, nonlesional epilepsy began to be treated with resection in the 1950s. Methodological improvements and increased understanding of pathophysiology followed, and the advent of stereotaxy and ablative technology in the 1960s and 1970s heralded a new era of minimally invasive, targeted procedures for lesional and nonlesional epilepsy. Current techniques combine stereotactic methods, improved ablative technologies, and electroencephalographic methods for a multidisciplinary approach to the neurosurgical treatment of epilepsy.

  12. 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...

  13. Osteoid Osteoma with a Multicentric Nidus: Interstitial Laser Ablation under MRI Guidance

    Directory of Open Access Journals (Sweden)

    David Kaul

    2013-01-01

    Full Text Available Osteoid osteoma (OO is a common benign tumor of the bone and is typically treated by thermal ablation with computed tomography (CT guidance. Only a few cases of multicentric OO have been described. We here report the case of an 11-year-old boy with multicentric OO of the right femur treated with laser ablation under open high-field MRI guidance. The steps of the interventional MRI procedure are described, discussing the benefits and disadvantages of MRI versus CT guidance especially with regard to younger patients.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  15. 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®

  16. Radial-arm-maze behavior of the red-footed tortoise (Geochelone carbonaria).

    Science.gov (United States)

    Mueller-Paul, Julia; Wilkinson, Anna; Hall, Geoffrey; Huber, Ludwig

    2012-08-01

    The radial-arm maze is an established method for testing an animal's spatial win-shift behavior. Research on mammals, birds, and fish has shown that the mastery of this task is commonly mediated, to different degrees, by two types of strategy: those based on external cues and those based on response stereotypy. In the present study we trained four red-footed tortoises (Geochelone carbonaria) to navigate an eight-arm radial maze while providing different levels of access to visual room cues. The results indicate that response stereotypy is the more prevalent mechanism in these tortoises, although navigation based on landmarks can also occur if learned initially. The findings suggest that tortoise spatial navigation may be more similar to that observed in mammals and birds than previously thought. PMID:22390619

  17. EVALUATION OF ANXIOLYTIC ACTIVITY OF CARUM COPTICUM BY USING ELEVATED PLUS MAZE AND OPEN FIELD METHOD

    Directory of Open Access Journals (Sweden)

    Kharade SM

    2011-04-01

    Full Text Available The clinical applications of benzodiazepines as anxiolytics are limited by their unwanted side effects. Therefore, the development of new pharmacological agents is well justified. Among medicinal plants, Carum copticum has been recommended for relief of anxiety and insomnia in Iranian folk medicine. Nevertheless, no pharmacological studies have thus far evaluated its effects on central nervous system. Therefore, the aim of this study was to examine if the aqueous extract of Carum copticum seeds has anxiolytics effect in mice. The anxiolytic effect of aqueous extract (200, 400mg/kg was examined in male albino mice using elevated plus-maze and open field as an animal model of anxiety. In the elevated plus-maze, aqueous extract at 200 mg/kg showed an anxiolytic effect by increasing the time spent on open arms and the percentage of open arm entries, compared to control group. These results suggest that the aqueous extract of Carum copticum seeds has anxiolytic effect.

  18. Impact of different termination modes on atrial fibrillation termination in catheter ablation of persistent atrial fibrillation

    Institute of Scientific and Technical Information of China (English)

    WANG Ping; MA Chang-sheng; DONG Jian-zeng; LONG De-yong; NING Man; TANG Ri-bo; YU Rong-hui; XUE Zeng-ming; SANG Cai-hua; JIANG Chen-xi

    2012-01-01

    Background The optimal endpoint for catheter ablation of persistent atrial fibrillation (AF) remains ambiguous.This study investigated the impact of AF termination as a procedural endpoint and the termination mode on long-term clinical outcome.Methods Two hundred and ninety-three patients who underwent stepwise ablation for persistent AF were categorized into the AF termination by ablation group and into the electrical cardioversion (CV) group.Subgroups were also analyzed based on different termination modes.Follow-up assessment included early recurrence and sinus rhythm (SR) maintenance.Results During initial ablation,33 patients (11.3%) were directly converted to SR,166 patients (56.7%) were converted to atrial tachycardia (AT) that subsequently restored SR with further ablation in 98 patients (33.4%),and a total of 162 patients (55.3%) underwent cardioversion due to persistent atrial arrhythmias.Comparison between termination by ablation and termination by cardioversion in patients exhibiting AF or AT revealed that no significant difference was observed in early recurrence (38.2% vs.43.8%,P=0.328) and SR maintenance (67.2% vs.59.8%,P=0.198) during the (23±7) months follow-up.Even after repeat ablation,the SR maintenance continued to exhibit no statistical difference in above two groups (72.5% vs.70.4%,P=0.686).Further analysis of subgroups,however,demonstrated that patients with AF terminated directly to SR experienced better clinical outcomes than other subgroups (P <0.05).Furthermore,atrial arrhythmias present during ablation have been implicated in prediction of recurrence mode:AF or AT (P <0.05).Conclusions Termination as a procedural endpoint is not associated with favorable long-term SR maintenance in persistent AF.AF methods that convert arrhythmia directly to SR have,however,been linked with improved clinical outcomes,although conversions to AT may not be correlated.Atrial arrhythmias observed during the ablation may be used to

  19. Comparisons of Online Reading Paradigms: Eye Tracking, Moving-Window, and Maze

    Science.gov (United States)

    Witzel, Naoko; Witzel, Jeffrey; Forster, Kenneth

    2012-01-01

    This study compares four methodologies used to examine online sentence processing during reading. Specifically, self-paced, non-cumulative, moving-window reading (Just et al. in "J Exp Psychol Gen" 111:228-238, 1982), eye tracking (see e.g., Rayner in "Q J Exp Psychol" 62:1457-1506, 2009), and two versions of the maze task (Forster et al. in…

  20. Slime mould solves maze in one pass ... assisted by gradient of chemo-attractants

    OpenAIRE

    Adamatzky, Andrew

    2011-01-01

    Plasmodium of Physarum polycephalum is a large cell, visible by unaided eye, which exhibits sophisticated patterns of foraging behaviour. The plasmodium's behaviour is well interpreted in terms of computation, where data are spatially extended configurations of nutrients and obstacles, and results of computation are networks of protoplasmic tubes formed by the plasmodium. In laboratory experiments and numerical simulation we show that if plasmodium of Physarum is inoculated in a maze's periph...

  1. Effect of Food Deprivation on a Delayed Nonmatch-to-place T-maze Task

    OpenAIRE

    Jang, Eun-Hae; Ahn, Seo-Hee; Lee, Ye-Seul; Lee, Hye-Ryeon; Kaang, Bong-Kiun

    2013-01-01

    Food deprivation can affect performance on difficult cognitive task, such as the delayed nonmatch-to-place T-maze task (DNMT). The importance of food deprivation on maintaining high motivation for DNMT task has been emphasized, but not many studies have investigated the optimal conditions for depriving rodents to maximize performance. Establishing appropriate conditions for food deprivation is necessary to maintain DNMT task motivation. We applied different conditions of food deprivation (1-h...

  2. Photoperiod interacts with food restriction on performance in the Barnes maze in female California mice

    OpenAIRE

    Steinman, Michael Q.; Crean, Katie K.; Trainor, Brian C.

    2010-01-01

    Food restriction has been reported to have positive effects on cognition. This study examines how another environmental factor, daylength, can alter the impact of food restriction on the brain and behavior. Female California mice (Peromyscus californicus), housed on either long days (16L:8D) or short days (8L:16D) were restricted to 80% of their normal baseline food intake or provided food ad libitum. Testing in a Barnes maze revealed that the effects of food restriction depend on photoperiod...

  3. Escalated handling of young C57BL/6 mice results in altered Morris water maze performance

    OpenAIRE

    Fridgeirsdottir, Gudrun Andrea; Hillered, Lars; Clausen, Fredrik

    2014-01-01

    Background The handling of experimental animals prior to experimental interventions is often poorly described, even though it may affect the final functional outcome. This study explores how the use of repeated handling of C57BL/6 mice prior to Morris water maze (MWM) tests can affect the performance. Methods and materials The handled animals were subjected to the escalating handling protocol, with the investigator spending 5 min per day per cage for 8 days prior to the MWM test. On the last ...

  4. Search Strategies Used by "APP" Transgenic Mice during Navigation in the Morris Water Maze

    Science.gov (United States)

    Janus, Christopher

    2004-01-01

    TgCRND8 mice represent a transgenic mouse model of Alzheimer's disease, with onset of cognitive impairment and increasing amyloid-[beta] plaques in their brains at 12 weeks of age. In this study, the spatial memory in 25- to 30-week-old TgCRND8 mice was analyzed in two reference and one working memory Morris water maze (MWM) tests. In reference…

  5. Long-term impoverished housing effects on morris maze performance after a fimbria lesion

    OpenAIRE

    Gispen, W. H.; Rijzingen, I.M.S.; Doremalen, E. van; Spruijt, B. M.

    1996-01-01

    Male Wistar rats received bilateral Fimbria lesions and were postoperatively housed in either standard social conditions or in impoverished conditions (one rat per cage) for 2 weeks in experiment I, and for 7 months in experiment II. The effects of lesion and housing conditions were investigated in the Morris maze spatial orientation task. Fimbria lesions increased the latency to reach the platform during acquisition in both experiments, which indicates that functional recovery of the Morris ...

  6. Water associated zero maze: a novel rat test for long term traumatic re-experiencing

    OpenAIRE

    Ritov, Gilad; Richter-levin, Gal

    2014-01-01

    Often, freezing and startle behaviors in the context of a previously experienced stress are taken as an indication of post-traumatic stress disorder (PTSD)-like symptoms in rats. However, PTSD is characterized by large individual variations of symptoms. In order to take into consideration the complex and long term distinctive variations in effects of trauma exposure additional behavioral measures are required. The current study used a novel behavioral test, the water associated zero maze (WAZ...

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

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Il Soo; Rhim, Hyun Chul; Koh, Byung Hee; Cho, On Koo; Seo, Heung Suk; Kim, Yong Soo; Kim, Young Sun; Heo, Jeong Nam [Hanyang University College of Medicine, Seoul (Korea, Republic of)

    2003-02-01

    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.

  8. Effects of telencephalic ablation on short-term memory and attention in goldfish.

    Science.gov (United States)

    Ohnishi, K

    1997-07-01

    Two hypotheses regarding the functions of the teleost telencephalon (short-term memory and nonspecific arousal hypotheses) were examined by using a Y-maze training paradigm. A delayed reinforcement method, which allowed the separation of choice process (a process in which choice responses are evoked) and reward process (a process in which choice responses are reinforced), showed that normal fish can acquire clear learned responses to choice stimuli under different stimulus conditions between the choice process and the reward process, while telencephalon-ablated fish showed greatly impaired learning performance. Neither normal nor telencephalon-ablated fish could acquire learned responses to choice stimuli under neutral stimulus conditions in the reward process with respect to choice stimuli in the choice process. These results suggest that the telencephalon facilitates extratelencephalic short-term memory function essential for memory retention of choice stimuli and evoked choice responses until reinforcement, and support the supplementary function of the telencephalon suggested previously [Ohnishi, K., Telencephalic function implicated in food-reinforced colour discrimination learning in the goldfish, Physiol. Behav., 46 (1989) 707-712 and Savage, G.E., Temporal factors in avoidance learning in normal and forebrainless goldfish (Carassius auratus), Nature, 218 (1968) 1168-1169]. In addition, it was shown that cue information in the reward process is very important for the fixation of short-term memory of choice stimuli and choice responses. Furthermore, telencephalon-ablated fish also showed clear visual aspect selection, as did normal fish, when they were reinforced to a visual compound stimulus containing heterogeneous aspects (pattern and colour). This result shows that the telencephalon-related arousal or attentional function is not critical for aspect selection in goldfish. It seems that visual aspect selection in goldfish is performed without paying

  9. 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.

  10. Endoscopic ultrasound-guided ethanol ablation ofpancreatic neuroendocrine tumours: A case study andliterature review

    Institute of Scientific and Technical Information of China (English)

    2016-01-01

    Here we offer a review of the literature regardingendoscopic ultrasound-guided ethanol ablation forpancreatic neuroendocrine tumours and describe thecase of a cystic tumour completely ablated after amultisession procedure. A total of 35 PubMed indexedcases of treated functioning and non-functioningpancreatic neuroendocrinetumours resulted fromour search, 29 of which are well-documented andsummarised. Endoscopic ultrasound-guided ethanolablation appears as a local, minimallyinvasive treatmentof pancreatic neuroendocrinetumours, suitable forselected patients. This techniqueappears feasible,relatively safe and efficient, especiallywhen applied tosymptom relief in functioning tumours, aiming at loss ofendocrine secretion. For non-functioning tumours, wherethe goal is complete tissue ablation, eus guided ethanolablation can provide good results for patients whoare unfit for surgery or for those who refuse surgicalresection. Its role in "fit for surgery" patients requiresassessment through further studies.

  11. Radiofrequency Ablation: A Minimally Invasive Approach in Kidney Tumor Management

    Energy Technology Data Exchange (ETDEWEB)

    Salagierski, Maciej, E-mail: maciej.salagierski@umed.lodz.pl [I Urology Department, Medical University of Lodz (Poland); Salagierski, Marek S. [II Urology Department, Medical University of Lodz (Poland)

    2010-11-17

    The management and diagnosis of renal tumors have changed significantly over the last decade. Due to advances in imaging techniques, more than 50% of kidney tumors are discovered incidentally and many of them represent an early stage lesion. This has stimulated the development of nephron-sparing surgery and of the minimally invasive treatment options including ablative techniques, i.e., radiofrequency ablation (RFA) and cryoablation. The objective of the minimally invasive approach is to preserve the renal function and to lower the perioperative morbidity. RFA involves inducing the coagulative necrosis of tumor tissue. Being probably one of the least invasive procedures in kidney tumor management, RFA may be performed percutaneously under ultrasound (US), computed tomography (CT) or magnetic resonance (MR) guidance. Most of the studies show that the RFA procedure is efficient, safe and has a low complication rate. Due to the still limited data on the oncological outcome of RFA, the indication for this intervention remains limited to selected patients with small organ-confined renal tumors and contraindication to surgery or who have a solitary kidney. The aim of our study is to review the literature on RFA of kidney tumors.

  12. Electrolytic ablation of the rat pancreas: a feasibility trial

    Directory of Open Access Journals (Sweden)

    Texler Michael

    2001-09-01

    Full Text Available Abstract Background Pancreatic cancer is a biologically aggressive disease with less than 20% of patients suitable for a "curative" surgical resection. This, combined with the poor 5-year survival indicates that effective palliative methods for symptom relief are required. Currently there are no ablative techniques to treat pancreatic cancer in clinical use. Tissue electrolysis is the delivery of a direct current between an anode and cathode to induce localised necrosis. Electrolysis has been shown to be safe and reliable in producing hepatic tissue and tumour ablation in animal models and in a limited number of patients. This study investigates the feasibility of using electrolysis to produce localised pancreatic necrosis in a healthy rat model. Method Ten rats were studied in total. Eight rats were treated with variable "doses" of coulombs, and the systemic and local effects were assessed; 2 rats were used as controls. Results Seven rats tolerated the procedure well without morbidity or mortality, and one died immediately post procedure. One control rat died on induction of anaesthesia. Serum amylase and glucose were not significantly affected. Conclusion Electrolysis in the rat pancreas produced localised necrosis and appears both safe, and reproducible. This novel technique could offer significant advantages for patients with unresectable pancreatic tumours. The next stage of the study is to assess pancreatic electrolysis in a pig model, prior to human pilot studies.

  13. Radiofrequency catheter ablation of atrial tachycardias related to myocardial scar or incision

    Institute of Scientific and Technical Information of China (English)

    Jianqiang HU; Jiang CAO; Shengqiang WANG; Yongwen QIN; Bingyan ZHOU

    2006-01-01

    Intra-atrial re-entrant tachycardias (IARTs) are common late after heart surgery. Conventional mapping and ablation is relatively difficult because of the complicated anatomy and multiple potential re-entry loops. In this study we aimed to evaluate the electrophysiological characteristics and radiofrequency catheter ablation of atrial tachycardia (AT) induced by myocardial scar or incision. Methods In 6 patients (three male and three female, aged 33.3+ 11.8 years) who had AT related to myocardial scar or incision,electrophysiological study and radiofrequency catheter ablation (RFCA) were performed. Earliest activation combined with entrainment mapping was adopted to determine a critical isthmus. Results Re-entry related to the lateral atriotomy scar was inducible in 5 of6 patients. With entrainment mapping, the PPI (post-pacing interval)-TCL (tachycardia cycle length) difference was <30 ms when pacing at the inferior margins of the right lateral atriotomy scar. Among them, 3 patients had successful linear ablation between scar area to inferior vena cava, and 2 patients between scar area to tricuspid annulus. Re-entry involving an ASD patch was demonstrated in 1 of 6 patients. PPI-TCL differences <30 ms were observed when entraining tachycardia at sites near the septal patch. But linear ablation failed in terminating AT. There was no complication during procedure. No recurrence of AT related to incision was observed during follow-up except for the failed patient. Conclusion Under conventional electrophysiological mapping, adopting linear ablation from scar area to anatomic barrier, successful ablation can be obtained in patients with IRATs related to myocardial scar or incision.

  14. 3D ablation catheter localisation using individual C-arm x-ray projections

    Science.gov (United States)

    Haase, C.; Schäfer, D.; Dössel, O.; Grass, M.

    2014-11-01

    Cardiac ablation procedures during electrophysiology interventions are performed under x-ray guidance with a C-arm imaging system. Some procedures require catheter navigation in complex anatomies like the left atrium. Navigation aids like 3D road maps and external tracking systems may be used to facilitate catheter navigation. As an alternative to external tracking a fully automatic method is presented here that enables the calculation of the 3D location of the ablation catheter from individual 2D x-ray projections. The method registers a high resolution, deformable 3D attenuation model of the catheter to a 2D x-ray projection. The 3D localization is based on the divergent beam projection of the catheter. On an individual projection, the catheter tip is detected in 2D by image filtering and a template matching method. The deformable 3D catheter model is adapted using the projection geometry provided by the C-arm system and 2D similarity measures for an accurate 2D/3D registration. Prior to the tracking and registration procedure, the deformable 3D attenuation model is automatically extracted from a separate 3D cone beam CT reconstruction of the device. The method can hence be applied to various cardiac ablation catheters. In a simulation study of a virtual ablation procedure with realistic background, noise, scatter and motion blur an average 3D registration accuracy of 3.8 mm is reached for the catheter tip. In this study four different types of ablation catheters were used. Experiments using measured C-arm fluoroscopy projections of a catheter in a RSD phantom deliver an average 3D accuracy of 4.5 mm.

  15. Fractal dimensions: A new paradigm to assess spatial memory and learning using Morris water maze.

    Science.gov (United States)

    Singh, Surjeet; Kaur, Harpreet; Sandhir, Rajat

    2016-02-15

    Morris water maze has been widely used for analysis of cognitive functions and relies on the time taken by animal to find the platform i.e. escape latency as a parameter to quantify spatial memory and learning. However, escape latency is confounded by swimming speed which is not necessarily a cognitive factor. Rather, path length may be a more appropriate and reliable parameter to assess spatial learning. This paper presents fractal dimension as a new paradigm to assess spatial memory and learning in animals. Male wistar rats were administrated with pentylenetetrazole and scopolamine to induce chronic epilepsy and dementia respectively. Fractal dimension of the random path followed by the animals on Morris water maze was analyzed and statistically compared among different experimental groups; the results suggest that fractal dimension is more reliable and accurate parameter to assess cognitive deficits compared to escape latency. Thus, the present study suggests that fractal dimensions could be used as an independent parameter to assess spatial memory and learning in animals using Morris water maze.

  16. Memory-impairing effects of local anesthetics in an elevated plus-maze test in mice

    Directory of Open Access Journals (Sweden)

    S.L. Blatt

    1998-04-01

    Full Text Available Post-training intracerebroventricular administration of procaine (20 µg/µl and dimethocaine (10 or 20 µg/µl, local anesthetics of the ester class, prolonged the latency (s in the retention test of male and female 3-month-old Swiss albino mice (25-35 g body weight; N = 140 in the elevated plus-maze (mean ± SEM for 10 male mice: control = 41.2 ± 8.1; procaine = 78.5 ± 10.3; 10 µg/µl dimethocaine = 58.7 ± 12.3; 20 µg/µl dimethocaine = 109.6 ± 5.73; for 10 female mice: control = 34.8 ± 5.8; procaine = 55.3 ± 13.4; 10 µg/µl dimethocaine = 59.9 ± 12.3 and 20 µg/µl dimethocaine = 61.3 ± 11.1. However, lidocaine (10 or 20 µg/µl, an amide class type of local anesthetic, failed to influence this parameter. Local anesthetics at the dose range used did not affect the motor coordination of mice exposed to the rota-rod test. These results suggest that procaine and dimethocaine impair some memory process(es in the plus-maze test. These findings are interpreted in terms of non-anesthetic mechanisms of action of these drugs on memory impairment and also confirm the validity of the elevated plus-maze for the evaluation of drugs affecting learning and memory in mice

  17. What is the most sensitive measure of water maze probe test performance?

    Directory of Open Access Journals (Sweden)

    Hamid R Maei

    2009-03-01

    Full Text Available The water maze is commonly used to assay spatial cognition, or, more generally, learning and memory in experimental rodent models. In the water maze, mice or rats are trained to navigate to a platform located below the water’s surface. Spatial learning is then typically assessed in a probe test, where the platform is removed from the pool and the mouse or rat is allowed to search for it. Performance in the probe test may then be evaluated using either occupancy-based (percent time in virtual quadrant [Q] or zone [Z] centered on former platform location, error-based (mean proximity to former platform location [P] or counting-based (platform crossings [X] measures. While these measures differ in their popularity, whether they differ in their ability to detect group differences is not known. To address this question we compiled 5 separate databases, containing more than 1600 mouse probe tests. Random selection of individual trials from respective databases then allowed us to simulate experiments with varying sample and effect sizes. Using this Monte Carlo-based method, we found that the P measure consistently outperformed the Q, Z and X measures in its ability to detect group differences. This was the case regardless of sample or effect size, and using both parametric and non-parametric statistical analyses. The relative superiority of P over other commonly used measures suggests that it is the most appropriate measure to employ in both low- and high-throughput water maze screens.

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

    Science.gov (United States)

    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.

  19. New Procedure for Treatment of Atrial Fibrillation in Patients with Valvular Heart Disease

    OpenAIRE

    Naser Safaie; Nasrollah Maghamipour; Ahmad Reza Jodati; Ata Mahmoodpoor; Leila Dashtaki; Masoud Hakimzadeh

    2010-01-01

    Patients with valvular heart disease suffer from atrial fibrillation for more than 12 months after valve surgery and have a low probability of remaining in sinus rhythm. We performed an intra-operative procedure similar to surgical maze ІІІ procedure for conversion of this arrhythmia to sinus rhythm. We did this study to evaluate the efficacy of this procedure to restore the sinus rhythm in patients with valvular heart disease. 28 patients with valvular heart disease and chronic persistent at...

  20. Laser induced ablation studies from gold target

    International Nuclear Information System (INIS)

    Laser produced gold plasmas show an enhanced mass ablation rate and ablation pressure as compared to theoretical prediction. This is attributed to radiation effect. Experimental results indicate an increase in the C-J point density and an agreement with self-regulating ablation scaling. Using 1.06 μm laser radiation on 12.5 μm thick planar gold targets, at an absorbed laser intensity IA ≤ 2 x 1013 W/cm2, the experimental results are presented. (Author)

  1. Ablation response testing of aerospace power supplies

    Science.gov (United States)

    Lutz, S. A.; Chan, C. C.

    1993-01-01

    An experimental program was performed to assess the aerothermal ablation response of aerospace power supplies. Full-scale General Purpose Heat Source (GPHS) test articles, Graphite Impact Shell (GIS) test articles, and Lightweight Radioisotope Heater Unit (LWRHU) test articles were all tested without nuclear fuel in simulated reentry environments at the NASA Ames Research Center. Stagnation heating, stagnation pressure, stagnation surface temperature, stagnation surface recession profile, and weight loss measurements were obtained for diffusion-limited and sublimation ablation conditions. The recession profile and weight loss measurements showed an effect of surface features on the stagnation face. The surface features altered the local heating which in turn affected the local ablation.

  2. The Atrial Fibrillation Ablation Pilot Study

    DEFF Research Database (Denmark)

    Arbelo, Elena; Brugada, Josep; Hindricks, Gerhard;

    2014-01-01

    was achieved in 40.7% of patients (43.7% in paroxysmal AF; 30.2% in persistent AF; 36.7% in long-lasting persistent AF). A second ablation was required in 18% of the cases and 43.4% were under antiarrhythmic treatment. Thirty-three patients (2.5%) suffered an adverse event, 272 (21%) experienced a left atrial...... tachycardia, and 4 patients died (1 haemorrhagic stroke, 1 ventricular fibrillation in a patient with ischaemic heart disease, 1 cancer, and 1 of unknown cause). CONCLUSION: The AFib Ablation Pilot Study provided crucial information on the epidemiology, management, and outcomes of catheter ablation of AFib...

  3. Investigation of different liquid media and ablation times on pulsed laser ablation synthesis of aluminum nanoparticles

    International Nuclear Information System (INIS)

    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.

  4. 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.

  5. Robotic magnetic navigation for ablation of human arrhythmias

    Science.gov (United States)

    Da Costa, Antoine; Guichard, Jean Baptiste; Roméyer-Bouchard, Cécile; Gerbay, Antoine; Isaaz, Karl

    2016-01-01

    Radiofrequency treatment represents the first choice of treatment for arrhythmias, in particular complex arrhythmias and especially atrial fibrillation, due to the greater benefit/risk ratio compared to antiarrhythmic drugs. However, complex arrhythmias such as atrial fibrillation require long procedures with additional risks such as X-ray exposure or serious complications such as tamponade. Given this context, the treatment of arrhythmias using robotic magnetic navigation entails a technique well suited to complex arrhythmias on account of its efficacy, reliability, significant reduction in X-ray exposure for both patient and operator, as well as a very low risk of perforation. As ongoing developments will likely improve results and procedure times, this technology will become one of the most modern technologies for treating arrhythmias. Based on the literature, this review summarizes the advantages and limitations of robotic magnetic navigation for ablation of human arrhythmias. PMID:27698569

  6. MRI-guided percutaneous laser ablation of small renal cell carcinoma: Initial clinical experience

    Energy Technology Data Exchange (ETDEWEB)

    Kariniemi, Juho; Ojala, Risto; Hellstroem, Pekka; Sequeiros, Roberto Blanco (Dept. of Radiology, Dept. of Surgery, Oulu Univ. Hospital, Oulu (Finland)), e-mail: juho.kariniemi@oulu.fi

    2010-05-15

    Background: The number of detected small renal cell carcinomas (RCCs) has been rising, largely due to advances in imaging. Open surgical resection is the standard management of small RCCs; however, imaging-guided percutaneous ablative therapies have emerged as a minimally invasive treatment alternative, especially for patients who are poor candidates for surgery. Purpose: To evaluate the initial clinical experience of magnetic resonance imaging (MRI)-guided percutaneous laser ablation of small RCCs. Material and Methods: Eight patients with 10 tumors were treated with percutaneous MRI-guided laser ablation. All tumors (diameter range 1.5-3.8 cm, mean 2.7 cm) were biopsy-proven RCCs. By using a 0.23 T open MRI system and general anesthesia in patients, one to four (mean 2.6) laser fibers were placed and the tumors were ablated under near real-time MRI control by observing the signal void caused by the temperature change in the heated tissue. The treatment was considered successful if the tumor showed no contrast enhancement at follow-up imaging. Results: All except one tumor were successfully ablated in one session. The first patient treated showed enhancing residual tumor in post-procedural MRI; she has thus far declined retreatment. One complication, a myocardial infarction, occurred; all other patients tolerated the procedure well. No local recurrence was discovered during the follow-up (range 12-30 months, mean 20 months). Conclusion: In this small group of patients with relatively short follow-up period, MRI-guided percutaneous laser ablation proved to be a promising treatment option for small RCCs

  7. Local Ablative Strategies for Ductal Pancreatic Cancer (Radiofrequency Ablation, Irreversible Electroporation): A Review

    OpenAIRE

    Salvatore Paiella; Roberto Salvia; Marco Ramera; Roberto Girelli; Isabella Frigerio; Alessandro Giardino; Valentina Allegrini; Claudio Bassi

    2016-01-01

    Pancreatic ductal adenocarcinoma (PDAC) has still a dismal prognosis. Locally advanced pancreatic cancer (LAPC) accounts for the 40% of the new diagnoses. Current treatment options are based on chemo- and radiotherapy regimens. Local ablative techniques seem to be the future therapeutic option for stage-III patients with PDAC. Radiofrequency Ablation (RFA) and Irreversible Electroporation (IRE) are actually the most emerging local ablative techniques used on LAPC. Initial clinical studies on ...

  8. Typical flutter ablation as an adjunct to catheter ablation of atrial fibrillation

    Directory of Open Access Journals (Sweden)

    Dipen Shah

    2008-12-01

    Full Text Available Typical atrial flutter and atrial fibrillation are frequently observed to coexist(1 .  In the current context of interventional electrophysiology, curative or at least definitive ablation is available for both arrhythmias. Despite their coexistence, it is not clear whether typical flutter ablation is necessary in all patients undergoing catheter ablation of atrial fibrillation. The following review explores the pathophysiology of both arrhythmias, their interrelationships and the available data pertaining to this theme.

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

    International Nuclear Information System (INIS)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

    Kim, Il Jung; Lee, Shin Jae; Shin, Min Woo; Shin, Won Sun; Chung, Yong Eun; Kim, Gyoung Min; Kim, Man Deuk; Won, Jong Yun; Lee, Do Yun; Choi, Jin Sub; Han, Kwang-Hyub

    2016-01-01

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

  12. Design and Laboratory Validation of a Capacitive Sensor for Measuring the Recession of Thin-Layered Ablator

    Science.gov (United States)

    Noffz, Gregory K.; Bowman, Michael P.

    1996-01-01

    Flight vehicles are typically instrumented with subsurface thermocouples to estimate heat transfer at the surface using inverse analysis procedures. If the vehicle has an ablating heat shield, however, temperature time histories from subsurface thermocouples no longer provide enough information to estimate heat flux at the surface. In this situation, the geometry changes and thermal energy leaves the surface in the form of ablation products. The ablation rate is required to estimate heat transfer to the surface. A new concept for a capacitive sensor has been developed to measure ablator depth using the ablator's dielectric effect on a capacitor's fringe region. Relying on the capacitor's fringe region enables the gage to be flush mounted in the vehicle's permanent structure and not intrude into the ablative heat shield applied over the gage. This sensor's design allows nonintrusive measurement of the thickness of dielectric materials, in particular, the recession rates of low-temperature ablators applied in thin (0.020 to 0.060 in. (0.05 to 0.15 mm)) layers. Twenty capacitive gages with 13 different sensing element geometries were designed, fabricated, and tested. A two-dimensional finite-element analysis was performed on several candidate geometries. Calibration procedures using ablator-simulating shims are described. A one-to-one correspondence between system output and dielectric material thickness was observed out to a thickness of 0.055 in. (1.4 mm) for a material with a permittivity about three times that of air or vacuum. A novel method of monitoring the change in sensor capacitance was developed. This technical memorandum suggests further improvements in gage design and fabrication techniques.

  13. Thermal ablation of liver metastases. Current status and perspectives; Thermische Ablation von Lebermetastasen. Aktueller Stand und Perspektiven

    Energy Technology Data Exchange (ETDEWEB)

    Vogl, T.; Mack, M.; Straub, R.; Zangos, S.; Woitaschek, D.; Eichler, K.; Engelmann, K. [Inst. fuer Diagnostische und Interventionelle Radiologie, Univ. Frankfurt (Germany)

    2001-01-01

    Purpose. To present thermal ablation of liver metastases via laser induced thermotherapy. Material and methods. Different technical procedures of thermal ablation and online monitoring are used, as there are the MR-guided laser induced thermotherapy (LITT) and the radiofrequency ablation thermotherapy (RF). Results. In a prospective non randomized study 606 patients with liver metastases were treated via MR-guided laserinduced thermotherapy. Inclusion criteria were the exclusion of extrahepatic tumor spread and a number of metastases lower than 5 and a size lower than 50 mm in diameter. The local tumor control rate in the 3 month and 6 month control study was 98,3%, the complication rate 3,5% (clinically relevant: 1,2%). The mean survival rate was 40,9 months for all patients with liver metastases without statistically relevant differences for various primaries, like colorectal carcinoma, breast cancer and various other tumors. Results for radiofrequency are so far limited with incidence of a higher local tumor recurrence rate versus LITT. Conclusion. MR-guided LITT results in a high local tumor control rate with improved survival. (orig.) [German] Zielsetzung. Vorstellung der thermischen Ablation von Lebermetastasen mittels laserinduzierter Thermotherapie (LITT). Material und Methodik. Verschiedene technische Verfahren der Ablation sowie 'Online-monitoring-Verfahren' werden vorgestellt. Derzeit gaengige Verfahren der Thermoablation stellen die MR-gesteuerte laserinduzierte Thermotherapie (LITT) sowie die Radiofrequenzablation (RF) dar. Ergebnisse. Im Rahmen einer prospektiven, nichtrandomisierten Studie wurden bislang 606 Patienten mit Lebermetastasen unterschiedlicher Primaertumoren mittels LITT perkutan therapiert. Die erzielte lokale Tumorkontrolle in der 3- bzw. 6-Monatskontrolle betrug dabei 98,3%, die Rate klinisch nicht relevanter Komplikationen 3,5%, die Rate klinisch relevanter Komplikationen 1,2%. Die mittlere Ueberlebensrate fuer das

  14. Atrial Tachycardias Occurring After Atrial Fibrillation Ablation: Strategies for Mapping and Ablation

    Directory of Open Access Journals (Sweden)

    Stavros Mountantonakis, MD

    2010-10-01

    Full Text Available The occurrence of left atrial tachycardias (AT after catheter ablation for atrial fibrillation (AF is common, especially after more extensive ablation of persistent AF. These AT are invariably symptomatic and often do not respond to medical therapy. The initial strategy involves ventricular rate control, cardioversion, and observation as some tachycardias may resolve with time. For persistent ATs, effective management frequently requires catheter intervention. Careful characterization of the tachycardia mechanism is essential in designing an effective ablation strategy that would also avoid further creation of pro-arrhythmic substrate. With this review, we summarize the incidence, mechanism, diagnosis and treatment of ATs occurring after AF ablation.

  15. Ultrasound ablation of pulmonary veins for treatment of paroxysmal atrial fibrillation

    Institute of Scientific and Technical Information of China (English)

    王建安; 孙勇; 何红

    2003-01-01

    Objective: to evaluate the efficacy and safety of ultrasound ablation of pulmonary veins for treatment of paroxysmal atrial fibrillation. Methods: The study population consisted of 9 patients with 5 males and 4 females enrolled consecutively who had idiopathic paroxysmal atrial fibrillation(AF). The ultrasound balloon was positioned through a special sheath to the orifice of the target vein by a transseptal procedure. The balloon was inflated with contrast-mixed saline (contrast: saline = 1:4) whose volume was decided by the diameter of the target pulmonary vein. The ablation energy was usually set up at 35 to 40 watts with temperature controlled at 60℃. The duration of each ablation was about 120 seconds which was repeated not over 10 times. Results: The average duration of the total procedure was 132±68 min for our patients. The average fluoroscopy time was 33±17 min. With a mean follow-up of 16±8 months after the procedure, AF was completely eliminated in 4 patients without antiarrhythmic drugs. The episodes of atrial fibrillation were eliminated in 2 patients with low dosage of oral amiodarone (0.1, once daily) which was ineffective before the procedure. The frequency of episodes was similar to that before the procedure in 3 patients. There were no complications such as hemopericardium, air embolism and stenosis of the pulmonary veins by angiography, related to the procedure. Conclusion: Ultrasound ablation of the pulmonary veins is a new approach to treat paroxysmal atrial fibrillation. Before we determined its value, we need to do more researches with bigger sample, randomization and comparison design.

  16. Ultrasound ablation of pulmonary veins for treatment of paroxysmal atrial fibrillation

    Institute of Scientific and Technical Information of China (English)

    王建安; 孙勇; 何红

    2003-01-01

    Objective : to evaluate the efficacy and safety of ultrasound ablation of pulmonary veins for treatment of paroxysmal atrial fibrillation. Methods : The study population consisted of 9 patients with 5 males and 4 females enrolled consecutively who had idiopathic paroxysmal atrial fibrillation(AF) . The ultrasound balloon was positioned through a special sheath to the orifice of the target vein by a transseptal procedure. The balloon was inflated with contrast-mixed saline (contrast: saline = 1:4) whose volume was decided by the diameter of the target pulmonary vein. The ablation energy was usually set up at 35 to 40 watts with temperature controlled at 60℃ . The duration of each ablation was about 120 seconds which was repeated not over 10 times. Results: The average duration of the total procedure was 132± 68 min for our patients. The average fluoroscopy time was 33 ±17 min. With a mean follow-up of 16 ±8 months after the procedure, AF was completely eliminated in 4 patients without antiarrhythmic drugs. The episodes of atrial fibrillation were eliminated in 2 patients with low dosage of oral amiodarone (0.1, once daily) which was ineffective before the procedure. The frequency of episodes was similar to that before the procedure in 3 patients. There were no complications such as hemopericardium, air embolism and stenosis of the pulmonary veins by angiography, related to the procedure. Conclusion : Ultrasound ablation of the pulmonary veins is a new approach to treat paroxysmal atrial fibrillation. Before we determined its value, we need to do more researches with bigger sample, randomization and comparison design.

  17. Nanosecond laser ablation of silver nanoparticle film

    Science.gov (United States)

    Chung, Jaewon; Han, Sewoon; Lee, Daeho; Ahn, Sanghoon; Grigoropoulos, Costas P.; Moon, Jooho; Ko, Seung H.

    2013-02-01

    Nanosecond laser ablation of polyvinylpyrrolidone (PVP) protected silver nanoparticle (20 nm diameter) film is studied using a frequency doubled Nd:YAG nanosecond laser (532 nm wavelength, 6 ns full width half maximum pulse width). In the sintered silver nanoparticle film, absorbed light energy conducts well through the sintered porous structure, resulting in ablation craters of a porous dome shape or crown shape depending on the irradiation fluence due to the sudden vaporization of the PVP. In the unsintered silver nanoparticle film, the ablation crater with a clean edge profile is formed and many coalesced nanoparticles of 50 to 100 nm in size are observed inside the ablation crater. These results and an order of magnitude analysis indicate that the absorbed thermal energy is confined within the nanoparticles, causing melting of nanoparticles and their coalescence to larger agglomerates, which are removed following melting and subsequent partial vaporization.

  18. Nanoscale ablation through optically trapped microspheres

    Science.gov (United States)

    Fardel, Romain; McLeod, Euan; Tsai, Yu-Cheng; Arnold, Craig B.

    2010-10-01

    The ability to directly create patterns with size scales below 100 nm is important for many applications where the production or repair of high resolution and density features is needed. Laser-based direct-write methods have the benefit of being able to quickly and easily modify and create structures on existing devices, but ablation can negatively impact the overall technique. In this paper we show that self-positioning of near-field objectives through the optical trap assisted nanopatterning (OTAN) method allows for ablation without harming the objective elements. Small microbeads are positioned in close proximity to a substrate where ablation is initiated. Upon ablation, these beads are temporarily displaced from the trap but rapidly return to the initial position. We analyze the range of fluence values for which this process occurs and find that there exists a critical threshold beyond which the beads are permanently ejected.

  19. Ablative Ceramic Foam Based TPS Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A novel composite material ablative TPS for planetary vehicles that can survive a dual heating exposure is proposed. NextGen's TPS concept is a bi-layer functional...

  20. Principles of the radiative ablation modeling

    Science.gov (United States)

    Saillard, Yves; Arnault, Philippe; Silvert, Virginie

    2010-12-01

    Indirectly driven inertial confinement fusion (ICF) rests on the setting up of a radiation temperature within a laser cavity and on the optimization of the capsule implosion ablated by this radiation. In both circumstances, the ablation of an optically thick medium is at work. The nonlinear radiation conduction equations that describe this phenomenon admit different kinds of solutions called generically Marshak waves. In this paper, a completely analytic model is proposed to describe the ablation in the subsonic regime relevant to ICF experiments. This model approximates the flow by a deflagrationlike structure where Hugoniot relations are used in the stationary part from the ablation front up to the isothermal sonic Chapman-Jouguet point and where the unstationary expansion from the sonic point up to the external boundary is assumed quasi-isothermal. It uses power law matter properties. It can also accommodate arbitrary boundary conditions provided the ablation wave stays very subsonic and the surface temperature does not vary too quickly. These requirements are often met in realistic situations. Interestingly, the ablated mass rate, the ablation pressure, and the absorbed radiative energy depend on the time history of the surface temperature, not only on the instantaneous temperature values. The results compare very well with self-similar solutions and with numerical simulations obtained by hydrodynamic code. This analytic model gives insight into the physical processes involved in the ablation and is helpful for optimization and sensitivity studies in many situations of interest: radiation temperature within a laser cavity, acceleration of finite size medium, and ICF capsule implosion, for instance.

  1. Retained Foreign Body After Laser Ablation

    OpenAIRE

    Ren, Shiyan; Liu, Peng; Wang, Wei; Yang, Yuguan

    2012-01-01

    Laser ablation for varicose veins is a common practice, and postoperative complications may happen. A retained foreign body could be left accidently in the treated leg. It is rarely reported in literature. We herein describe two cases of retained foreign body during the laser ablation for varicose veins. One patient with varicose veins received laser therapy 5 years earlier, and had experienced discomfort and pain. After investigation, an overlooked sheath fragment was removed surgically from...

  2. Responding changes systematically within sessions during conditioning procedures.

    OpenAIRE

    McSweeney, F K; Roll, J M

    1993-01-01

    When the procedure is held constant within an experimental session, responding often changes systematically within that session. Many of these within-session changes in responding cannot be dismissed as learning curves or by-products of satiation. They have been observed in studies of positive reinforcement, avoidance, punishment, extinction, discrimination, delayed matching to sample, concept formation, maze and alley running, and laboratory analogues of foraging, as well as in the unconditi...

  3. Laser Ablation for Small Hepatocellular Carcinoma

    Science.gov (United States)

    Pacella, Claudio Maurizio; Francica, Giampiero; Di Costanzo, Giovanni Giuseppe

    2011-01-01

    Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide and is increasingly detected at small size (liver transplantation, or percutaneous ablation have been proposed. When surgical options are precluded, image-guided tumor ablation is recommended as the most appropriate therapeutic choice in terms of tumor local control, safety, and improvement in survival. Laser ablation (LA) represents one of currently available loco-ablative techniques: light is delivered via flexible quartz fibers of diameter from 300 to 600 μm inserted into tumor lesion through either fine needles (21g Chiba needles) or large-bore catheters. The thermal destruction of tissue is achieved through conversion of absorbed light (usually infrared) into heat. A range of different imaging modalities have been used to guide percutaneous laser ablation, but ultrasound and magnetic resonance imaging are most widely employed, according to local experience and resource availability. Available clinical data suggest that LA is highly effective in terms of tumoricidal capability with an excellent safety profile; the best results in terms of long-term survival are obtained in early HCC so that LA can be proposed not only in unresectable cases but, not differently from radiofrequency ablation, also as the first-line treatment. PMID:22191028

  4. Optical modeling of laser ablated microstructures

    Science.gov (United States)

    Gower, M. C.; Davies, E.; Holmes, A. S.

    2012-11-01

    From only an a priori knowledge of the optical parameters of a laser beam, the delivery system together with a substrate's material properties, a ray-tracing model capable of predicting the 3-D topology of micro/nanostructures machined by pulsed laser ablation has been developed. The model includes secondary illumination effects produced by the microstructure created by successive pulses (wall reflections, refraction, wave guiding, shadowing, etc.) as well as the complete optical properties of the beam delivery system. We have used material ablation by pulsed excimer lasers and associated beam delivery systems to demonstrate some of the capabilities of the model. Good agreement is obtained between computations and experimental results in terms of the predicted ablation depth per pulse and the wall taper angle of channels and holes. The model can predict ablated profiles of holes and indicate the most efficient drilling strategy in terms of material removal rates. The model also shows diffraction effects are not required to explain the tapering vertical walls observed when ablating microstructures. Finally, the model has been used to demonstrate aberrations in an optical imaging system limiting the creation of submicron features in an ablated microstructure. Provided photons are absorbed linearly in a substrate according to Beer's law with negligible thermal diffusion effects, the model is equally applicable to using other types of pulsed laser sources and systems with imaged or focused beams.

  5. Basic ablation phenomena during laser thrombolysis

    Science.gov (United States)

    Sathyam, Ujwal S.; Shearin, Alan; Prahl, Scott A.

    1997-05-01

    This paper presents studies of microsecond ablation phenomena that take place during laser thrombolysis. The main goals were to optimize laser parameters for efficient ablation, and to investigate the ablation mechanism. Gelatin containing an absorbing dye was used as the clot model. A parametric study was performed to identify the optimal wavelength, spot size, pulse energies, and repetition rate for maximum material removal. The minimum radiant exposures to achieve ablation at any wavelength were measured. The results suggest that most visible wavelengths were equally efficient at removing material at radiant exposures above threshold. Ablation was initiated at surface temperatures just above 100 degrees Celsius. A vapor bubble was formed during ablation. Less than 5% of the total pulse energy is coupled into the bubble energy. A large part of the delivered energy is unaccounted for and is likely released partly as acoustic transients from the vapor expansion and partly wasted as heat. The current laser and delivery systems may not be able to completely remove large clot burden that is sometimes encountered in heart attacks. However, laser thrombolysis may emerge as a favored treatment for strokes where the occlusion is generally smaller and rapid recanalization is of paramount importance. A final hypothesis is that laser thrombolysis should be done at radiant exposures close to threshold to minimize any damaging effects of the bubble dynamics on the vessel wall.

  6. In vitro assessment of fiber sweeping angle during Q-switched 532-nm laser tissue ablation

    Science.gov (United States)

    Rajabhandharaks, Danop; Kang, Hyun Wook; Ko, Woo Jin; Stinson, Douglas; Choi, Benjamin

    2011-03-01

    Photoselective vaporization of the prostate (PVP) has been widely used to treat benign prostatic hyperplasia (BPH). It is well regarded as a safe and minimally invasive procedure and an alternative to the gold standard transurethral resection of the prostate (TURP). Despite of its greatness, as well aware of, the operative procedure time during the PVP is still prolonged. Such attempts have been tried out in order to shorten the operative time and increase its efficacy. However, scientific study to investigate techniques used during the PVP is still lacking. The objective of this study is to investigate how sweeping angle might affect the PVP performance. Porcine kidneys acquired from a local grocery store were used (N=140). A Q-switched 532-nm GreenLight XPSTM (American Medical Systems, Inc., MN, USA), together with 750- μm core MoXyTM fiber, was set to have power levels of 120 W and 180 W. Treatment speed and sweeping speed were fixed at 2 mm/s and 0.5 sweep/s, respectively. Sweeping angles were varied from 0 (no sweeping motion) to 120 degree. Ablation rate, depth, and coagulation zone were measured and quantified. Tissue ablation rate was peaked at 15 and 30 degree for both 120- and 180-W power levels and dramatically decreased beyond 60 degree. At 180 W, ablation rate increased 20% at 30 degree compared to 0 degree. This study demonstrated that ablation rate could be maximized and was contingent upon sweeping angle.

  7. 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.

  8. RADIOFREQUENCY CATHETER ABLATION OF PERMANENT ATRIAL FIBRILLATION UNDER GUIDANCE OF CARTO-MERGE TECHNIQUE

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objective To investigate the feasibility and effectiveness of radiofrequency catheter ablation (RFCA) to treat permanent atrial fibrillation (AF) under the guidance of Carto-Merge technique.Methods Fifteen male patients with permanent AF underwent RFCA under the guidance of Carto-Merge technique. The mean age was 54. 00 ± 10. 44 years, and duration of AF was 23.66 ± 14. 93 months. Cardiac magnetic resonance angiography (MRA) was performed to obtain pre-procedural three-dimensional (3D) images on the anatomy of left atrium (LA) and pulmonary veins (PVs) before RFCA procedure. Then the electroanatomical map was integrated with 3D images of MRA to form Carto-Merge map that guided step-by-step ablation strategy of permanent AF. Circumferential PV ablation was performed first until complete PVs electric isolation confirmed by Lasso catheter. If AF was not terminated, lesion lines on roof of LA, mitral isthmus, and tricuspid isthmus were produced.Results The episodes of AF were terminated during RFCA in 2 patients, by direct current cardioversion in the remaining 13 patients. Transient AF occurred in 2 patients after ablation on 1st day and 1st week respectively, AF terminated spontaneously not long after taking metoprolol. One patient developed persistent atrial flutter (AFL) in 2 months after procedure and AFL was eliminated by the second ablation. Persistent AF recurred on 1st day, 1st and 5th week respectively in 3 patients, and did not terminate after 3 months even though amiodarone was given The remaining 12 patients were all free of AF during 2-11 months of follow-up. The recent success rate for RFCA of permanent AF was 80%.Conclusions Carto-Merge technique can effectively guide RFCA of permanent AF. When combined with single Lasso mapping, it can simplify the mapping, lower expenses, and enhance the success rate of RFCA of permanent AF.

  9. Radiofrequency ablation combined with transarterial chemoembolization for treating of hepatic metastases

    International Nuclear Information System (INIS)

    Objective: To investigate the efficacy and safety of radiofrequency ablation (RFA) combined with transarterial chemoembolization (TACE) for treating of hepatic metastasis. Methods: From Mar. 2005 to Oct. 2010, 22 males and 14 females with hepatic metastasis were enrolled in this study. Mean age of the patients was 63±12 (42-82) years. Tumor size was (4.5±2.4) cm (min. 1.5 cm, max. 12.0 cm). Totally 47 lesions were treated with single metastasis in 29 cases and multiple ones in 7 cases. All cases were failed to chemotherapy or could not stand for the side effect of chemotherapy. Contrast enhanced CT scan was given to all patients before RFA + TACE. For lesions with rich blood supply, TACE was given and then RFA. For those with poor blood supply, RFA was given first and then TACE. For multiple lesions, RFA + TACE was given one by one for each lesion. As for follow up, ultrasound and blood check was given monthly. Enhanced CT scan was given every 3 month. For residual lesions or recurrent lesions, RFA + TACE were given repeatedly. The whole patients was divided into two groups according to the image follow up including complete ablation group and partial ablation group. For complete ablation group, no further treatment was given. For partial ablation group, if it was not suitable for further RFA, repeated TACE was given there after. The end point of follow up was death event. Survival of the whole group and the two subgroups was analyzed statistically by Kaplan-Meier method. Results: All RFA procedures was given under intravenous anesthesia and local anesthesia, no severe complication was noted. Lesions in 16 patients were completely ablated after single or multiple sections of RFA + TACE. Twenty patients were in the partially ablated group. Follow up time was 25±10 (10-40) months, Twenty-thee patients died and 13 kept alive during the follow up time. The estimated median survival time was 27 month (95% C/: 24- 32 months). Survival ration at 1, 2, 3 years for the

  10. In vivo study of necrosis on the liver tissue of Wistar rats: a combination of photodynamic therapy and carbon dioxide laser ablation

    International Nuclear Information System (INIS)

    Photodynamic therapy (PDT) is known to be limited to applications in large volume tumors due to its limited penetration. Therefore, a combination of PDT and carbon dioxide (CO2) laser ablation may constitute a potential protocol to destroy bulk tumors because it involves an association of these two techniques allowing the removal of visible lesions with a high selectivity of destruction of remnant tumors. The main aim of this study is to investigate the most appropriate procedure to combine use of a CO2 laser and PDT on livers of healthy rats, and to analyze different techniques of this treatment using three types of photosensitizers (PSs). Forty eight animals were separated to form six groups: (1) only CO2 laser ablation, (2) drug and CO2 laser ablation, (3) only PDT, (4) drug and light (PDT) followed by CO2 laser ablation, (5) ablated with CO2 laser followed by PDT, and (6) drug followed by CO2 laser ablation and light. For each group, three types of photosensitization were used: topical 5-aminolevulinic acid (ALA), intravenous ALA and intravenous Photogem®. Thirty hours after the treatments, the animals were sacrificed and the livers removed. The depth of necrosis was analyzed and measured, considering microscopic and macroscopic aspects. The results show that the effects of the PDT were considerably enhanced when combined with CO2 laser ablation, especially when the PDT was performed before the CO2 laser ablation. (paper)

  11. Dust ablation in Pluto's atmosphere

    Science.gov (United States)

    Horanyi, Mihaly; Poppe, Andrew; Sternovsky, Zoltan

    2016-04-01

    Based on measurements by dust detectors onboard the Pioneer 10/11 and New Horizons spacecraft the total production rate of dust particles born in the Edgeworth Kuiper Belt (EKB) has been be estimated to be on the order of 5 ṡ 103 kg/s in the approximate size range of 1 - 10 μm. Dust particles are produced by collisions between EKB objects and their bombardment by both interplanetary and interstellar dust particles. Dust particles of EKB origin, in general, migrate towards the Sun due to Poynting-Robertson drag but their distributions are further sculpted by mean-motion resonances as they first approach the orbit of Neptune and later the other planets, as well as mutual collisions. Subsequently, Jupiter will eject the vast majority of them before they reach the inner solar system. The expected mass influx into Pluto atmosphere is on the order of 200 kg/day, and the arrival speed of the incoming particles is on the order of 3 - 4 km/s. We have followed the ablation history as function of speed and size of dust particles in Pluto's atmosphere, and found that volatile rich particles can fully sublimate due to drag heating and deposit their mass in narrow layers. This deposition might promote the formation of the haze layers observed by the New Horizons spacecraft. This talk will explore the constraints on the composition of the dust particles by comparing the altitude of the deposition layers to the observed haze layers.

  12. Fractional ablative erbium YAG laser

    DEFF Research Database (Denmark)

    Taudorf, Elisabeth H; Haak, Christina S; Erlendsson, Andrés M;

    2014-01-01

    BACKGROUND AND OBJECTIVES: Treatment of a variety of skin disorders with ablative fractional lasers (AFXL) is driving the development of portable AFXLs. This study measures micropore dimensions produced by a small 2,940 nm AFXL using a variety of stacked pulses, and determines a model correlating...... laser parameters with tissue effects. MATERIALS AND METHODS: Ex vivo pig skin was exposed to a miniaturized 2,940 nm AFXL, spot size 225 µm, density 5%, power levels 1.15-2.22 W, pulse durations 50-225 microseconds, pulse repetition rates 100-500 Hz, and 2, 20, or 50 stacked pulses, resulting in pulse...... 190 to 347 µm. CONCLUSIONS: Pulse stacking with a small, low power 2,940 nm AFXL created reproducible shallow to deep micropores, and influenced micropore configuration. Mathematical modeling established relations between laser settings and micropore dimensions, which assists in choosing laser...

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

    International Nuclear Information System (INIS)

    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.)

  14. 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.)

  15. Femtosecond ultraviolet laser ablation of silver and comparison with nanosecond ablation

    DEFF Research Database (Denmark)

    Christensen, Bo Toftmann; Doggett, B.; Budtz-Jørgensen, C.;

    2013-01-01

    The ablation plume dynamics arising from ablation of silver with a 500 fs, 248 nm laser at ~2 J cm-2 has been studied using angle-resolved Langmuir ion probe and thin film deposition techniques. For the same laser fluence, the time-of-flight ion signals from femtosecond and nanosecond laser...

  16. Ablation enhancement of silicon by ultrashort double-pulse laser ablation

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Xin; Shin, Yung C. [Center for Laser-Based Manufacturing, School of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)

    2014-09-15

    In this study, the ultrashort double-pulse ablation of silicon is investigated. An atomistic simulation model is developed to analyze the underlying physics. It is revealed that the double-pulse ablation could significantly increase the ablation rate of silicon, compared with the single pulse ablation with the same total pulse energy, which is totally different from the case of metals. In the long pulse delay range (over 1 ps), the enhancement is caused by the metallic transition of melted silicon with the corresponding absorption efficiency. At ultrashort pulse delay (below 1 ps), the enhancement is due to the electron excitation by the first pulse. The enhancement only occurs at low and moderate laser fluence. The ablation is suppressed at high fluence due to the strong plasma shielding effect.

  17. Behavioral profiles displayed by rats in an elevated asymmetric plus-maze: effects of diazepam

    Directory of Open Access Journals (Sweden)

    Ruarte M.B.

    1999-01-01

    Full Text Available When rats are exposed to unknown environments where novelty and fear-inducing characteristics are present (conflictive environments, some specific behaviors are induced and exploration is apparently modulated by fear. In our laboratory, a new type of plus-maze was designed as a model of conflictive exploration. The maze is composed of four arms with different geometrical characteristics, differing from each other by the presence or absence of walls. The degree of asymmetry was as follows: NW, no wall arm; SW, a single high wall present; HL, a low and a high wall present, and HH, two high walls present. The four arms were arranged at 90o angles and the apparatus was called the elevated asymmetric plus-maze (APM. The purpose of the present study was to assess the behavioral profile of rats exposed for a single time to the APM with or without treatment with benzodiazepine. Increasing doses of diazepam were injected intraperitoneally in several groups of male, 90-day-old Holtzman rats. Distilled water was injected in control animals. Thirty minutes after treatment all rats were exposed singly to a 5-min test in the APM. Diazepam induced a biphasic modification of exploration in the NW and SW arms. The increase in the exploration score was evident at low doses of diazepam (0.25-1.0 mg/kg body weight and the decrease in exploration was found with the higher doses of diazepam (2.0-3.0 mg/kg body weight. Non-exploratory behaviors (permanency were not affected by benzodiazepine treatment. In the HL arm, exploration was not modified but permanency was increased in a dose-dependent manner. In the HH arm, exploration and permanency were not affected. Results are compatible with the idea that exploration-processing mechanisms in conflictive environments are modulated by fear-processing mechanisms of the brain.

  18. Behavioral profiles displayed by rats in an elevated asymmetric plus-maze: effects of diazepam.

    Science.gov (United States)

    Ruarte, M B; Alvarez, E O

    1999-01-01

    When rats are exposed to unknown environments where novelty and fear-inducing characteristics are present (conflictive environments), some specific behaviors are induced and exploration is apparently modulated by fear. In our laboratory, a new type of plus-maze was designed as a model of conflictive exploration. The maze is composed of four arms with different geometrical characteristics, differing from each other by the presence or absence of walls. The degree of asymmetry was as follows: NW, no wall arm; SW, a single high wall present; HL, a low and a high wall present, and HH, two high walls present. The four arms were arranged at 90 degrees angles and the apparatus was called the elevated asymmetric plus-maze (APM). The purpose of the present study was to assess the behavioral profile of rats exposed for a single time to the APM with or without treatment with benzodiazepine. Increasing doses of diazepam were injected intraperitoneally in several groups of male, 90-day-old Holtzman rats. Distilled water was injected in control animals. Thirty minutes after treatment all rats were exposed singly to a 5-min test in the APM. Diazepam induced a biphasic modification of exploration in the NW and SW arms. The increase in the exploration score was evident at low doses of diazepam (0.25-1.0 mg/kg body weight) and the decrease in exploration was found with the higher doses of diazepam (2.0-3.0 mg/kg body weight). Non-exploratory behaviors (permanency) were not affected by benzodiazepine treatment. In the HL arm, exploration was not modified but permanency was increased in a dose-dependent manner. In the HH arm, exploration and permanency were not affected. Results are compatible with the idea that exploration-processing mechanisms in conflictive environments are modulated by fear-processing mechanisms of the brain. PMID:10347776

  19. A role for puberty in water maze performance in male and female rats.

    Science.gov (United States)

    Willing, Jari; Drzewiecki, Carly M; Cuenod, Bethany A; Cortes, Laura R; Juraska, Janice M

    2016-08-01

    Adolescence is characterized by neuroanatomical changes that coincide with increased cognitive performance. This developmental period is particularly important for the medial prefrontal cortex (mPFC), which mediates higher-order cognitive functioning. The authors' laboratory has shown that puberty is associated with sex-specific changes in neuron number and the dendritic tree in the rat mPFC, but the effects of pubertal onset on cognitive performance remain relatively unexplored. Here, we use a water maze task to assess spatial memory for the location of an escape platform, followed by a test of reversal learning, when the platform is moved to an alternate quadrant in the maze. For both males and females, 2 groups of prepubertal animals were tested (postnatal day [P]30 and P33 for females, P40 and P43 for males), along with 1 group of newly (2 days) postpubertal animals and 1 group of young adults (P60). There were no group differences in learning the initial location of the platform or when the platform location changed, although grouping pre- and postpubertal ages did result in significantly better performance in postpubertal animals. In addition after the platform location changed, individual prepubertal males and females spent a significantly greater percentage of time in the quadrant of the maze where the platform was formerly located than the postpubertal animals. This collectively implies that pubertal onset in both males and females coincides with improved performance on a reversal task, which may be linked with the neuroanatomical changes occurring in the mPFC during this time. (PsycINFO Database Record PMID:27054406

  20. Individual differences in the elevated plus-maze and the forced swim test.

    Science.gov (United States)

    Estanislau, Celio; Ramos, Anna Carolina; Ferraresi, Paula Daniele; Costa, Naiara Fernanda; de Carvalho, Heloisa Maria Cotta Pires; Batistela, Silmara

    2011-01-01

    The elevated plus-maze is an apparatus composed of enclosed and open (elevated) arms and time spent in the open arms by a rat can be increased/decreased by anxiolytic/anxiogenic agents. In the forced swim test, floating behavior is used as an index of behavioral despair and can be decreased by antidepressant agents. As the comorbidity between anxiety and depression is a remarkable issue in human behavioral disorders, a possible relationship between the behaviors seen in the cited tests is of great relevance. In the present study, fifty-four male rats (Rattus norvegicus) were submitted to a plus-maze session and to a 2-day forced swim protocol. According to their time in the open arms, they were divided into three groups: Low Open, Medium Open and High Open. Some plus-maze measures were found to be coherent with time in the open arms and are suggested to also be reliable anxiety indexes. In the forced swim test, the Low Open group showed decreases in floating duration from forced swim Session 1 to Session 2, an alteration opposite to that observed in the other groups (particularly, the Medium Open group). The Low Open group also showed increases in floating latency, again in sharp contrast with the alteration found in the other groups. Accordingly, positive and negative correlation were found between time in the open arms and floating duration and latency, respectively. Results are compared to previous studies and mediation of the effect by reactivity to aversive stimulation or alterations induced by open arm exposure is discussed.

  1. Mechanism of Spatiotemporal Distribution of Laser Ablated Materials

    Institute of Scientific and Technical Information of China (English)

    XU Rong-Qing; CUI Yi-Ping; LU Jian; NI Xiao-Wu

    2009-01-01

    Interaction between subsequent laser and ablated materials in laser processing changes the laser spatiotemporal distribution and has influences on the efficiency and quality of laser processing. The theoretical and experimental researches on transportation behayiour of ablated materials are provided. It is shown that the velocity distribution of ablated materials is determined by ablation mechanism. The transportation behaviour of ablated materials is controlled by diffusion mechanism and light field force during laser pulse duration while it is only determined by diffusion mechanism when the laser pulse terminates. In addition, the spatiotemporal distribution of ablated materials is presented.

  2. Laser ablation of hepatocellular carcinoma-A review

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A wide range of local thermal ablative therapies have been developed in the treatment of non resectable hepatocellular carcinoma (HCC) in the last decade. Laser ablation (LA) and radiofrequency ablation (RFA) are the two most widely used of these. This article provides an up to date overview of the role of laser ablation in the local treatment of HCC. General principles, technique, image guidance and patient selection are discussed. A review of published data on treatment efficacy, long term outcome and complication rates of laser ablation is included and comparison with RFA made. The role of laser ablation in combination with transcatheter arterial chemoembolisation is also discussed.

  3. Endoscopic ultrasound-guided ethanol ablation of a large metastatic carcinoid tumor: success with a note of caution.

    Science.gov (United States)

    Mathers, Bradley W; Harvey, Harold A; Dye, Charles E; Dougherty-Hamod, Brandy; Moyer, Matthew T

    2014-12-01

    Endoscopic ultrasonography with fine needle infusion (EUS-FNI) of alcohol is the most reported method for EUS-guided tumor ablation. Several studies have reported successful EUS-guided ablation of pancreatic neuroendocrine tumors. However, these tumors have been relatively small (tumor with a large porta hepatis mass was referred to our clinic for EUS-guided ethanol ablation. After two separate EUS-FNI ablations, there was a 36 % reduction in tumor size (9.0 × 11.4 cm to 6.7 × 9.8 cm) with associated tumor lysis syndrome. Chromogranin A levels decreased from 460 to 132 ng/mL. The patient reported complete resolution of abdominal pain within 2 weeks, but only mild improvement in flushing and diarrhea. In conclusion, large metastatic neuroendocrine tumors can be successfully treated with EUS-guided ethanol ablation. Evidence-based guidelines are needed with regard to the appropriate volume of ethanol injected in EUS-guided ablation to promote the efficacy and safety of this emerging procedure. PMID:26135103

  4. 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. PMID:27607281

  5. Estradiol to aged female or male mice improves learning in inhibitory avoidance and water maze tasks

    OpenAIRE

    Frye, Cheryl A.; Rhodes, Madeline E; Dudek, Bruce

    2005-01-01

    Although 17β-Estradiol (E2) improves cognitive performance of aged female mice, its mnemonic effects when administered post-training to aged male mice have not been examined. E2 (10 µg, SC) or oil vehicle was administered to intact, 24-month-old female or male congenic (primarily C57BL/6 background) mice immediately after training in the inhibitory avoidance or water maze tasks. Following behavioral testing, effects of 1 or 24 h of E2 exposure on hippocampal levels of E2 and brain-derived neu...

  6. 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

    for their lack of vision. Little is known, however, about the neural mechanisms underlying spatial navigation in blind individuals in settings where these cues are absent. We therefore measured behavioural performance and blood oxygenation-level dependant (BOLD) responses using functional magnetic resonance...... and parahippocampus, occipital cortex and fusiform gyrus. Blindfolded sighted controls did not show increased BOLD responses in these areas; instead they activated the caudate nucleus and thalamus. Both groups activated the precuneus during tactile maze navigation. We conclude that cross-modal plastic processes allow...

  7. Ultrasonography guided percutaneous radiofrequency ablation for hepatic cavernous hemangioma

    Institute of Scientific and Technical Information of China (English)

    Yan Cui; Hong-Wen Zhang; Li-Yan Zhou; Man-Ku Dong; Ping Wang; Min Ji; Xiao-Ou Li; Chang-Wei Chen; Zi-Pei Liu; Yong-Jie Xu

    2003-01-01

    AIM: Hepatic cavernous hemangioma (HCH) is the mostcommon benign tumor of the liver and its management isstill controversial. Recent successin situ radiofrequencyablation of hepatic malignancies has led us to consider usingthis technique in patients with HCH. This study was to assessthe efficacy, safety, and complications of percutaneousradiofrequency ablation (PRFA) under ultrasonographyguidance in patients with HCH.METHODS: Twelve patients (four men and eight women,age ranged 33-56 years, mean age was 41.7 years) with 15hepatic cavernous hemangiomas (2.5 cm to 9.5 cm) weretreated using the RF-2000 generator and 10-needle LeVeenelectrode percutaneously guided by B-ultrasound. Lesionslarger than 3 cm were treated by multiple overlappingablations that encompass the entire lesion as well as a rimof normal liver tissue (approximately 0.5 cm).RESULTS: All the patients who received PRFA therapy hadno severe pain, bleeding or bile leakage during and afterthe procedures. Nine to 34 months′ follow-up (mean, 21months) by ultrasound and/or spiral CT scan demonstratedthat the ablated lesions in this group were shrunk remarkably,and the shrunken range was 38-79 % (mean, 67 % per 21months). The contrast enhancement was disappeared withinthe tumor or at its periphery in all cases on spiral CT scansobtained 3 to 6 months after treatment.CONCLUSION: The results of this study suggest that PRFAtherapy is a mini-invasive, simple, safe, and effective methodfor the treatment of selected patients with HCH.

  8. Egocentric spatial orientation in a water maze by rats subjected to transection of the fimbria-fornix and/or ablation of the prefrontal cortex

    DEFF Research Database (Denmark)

    Mogensen, Jesper; Moustgaard, Anette; Khan, Usman;

    2005-01-01

    prefrontal cortex, hippocampus, fimbria-fornix, egocentrisk spatial orientering, vandlabyrint, adfærdsstrategier, kognitive strategier, funktionel genopretning, rehabilitering, problemløsning, rotter...

  9. 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.

  10. Fundamental studies of pulsed laser ablation

    CERN Document Server

    Claeyssens, F

    2001-01-01

    dopant) have resulted in a coherent view of the resulting plume, which exhibits a multi-component structure correlated with different regimes of ablation, which are attributed to ejection from ZnO and ablation from a Zn melt. OES measurements show that the emitting Zn component within the plume accelerates during expansion in vacuum - an observation attributable to the presence of hot, fast electrons in the plume. The same acceleration behaviour is observed in the case of Al atomic emissions resulting from ablation of an Al target in vacuum. Deposition conditions, substrate temperature and background gas pressure were all varied in a quest for optimally aligned, high quality ZnO thin films. Initial ab initio calculations were performed also, to aid in understanding the stability of these c-axis aligned films. The pulsed ultraviolet (lambda = 193, 248 nm) laser ablation of graphite, polycrystalline diamond and ZnO targets has been investigated. Characteristics of the resulting plumes of ablated material have b...

  11. Percutaneous tumor ablation in medical radiology

    Energy Technology Data Exchange (ETDEWEB)

    Vogl, T.J.; Mack, M.G. [University Hospital Frankfurt Univ. (Germany). Inst. for Diagnostic and Interventional Radiology; Helmberger, T.K. [Klinikum Bogenhausen, Academic Teaching Hospital of the Technical Univ. Munich (Germany). Dept. for Diagnostic and Interventional Radiology and Nuclear Medicine; Reiser, M.F. (eds.) [University Hospitals - Grosshadern and Innenstadt Munich Univ. (Germany). Dept. of Clinical Radiology

    2008-07-01

    Thermal ablation has become an integral part of oncology, especially in the field of interventional oncology. This very comprehensive book encompasses the different technologies employed in thermal ablation, its indications and the results achieved in various clinical conditions. The first part of the book clearly explains the basics of thermal ablative techniques such as laser-induced thermotherapy, radiofrequency ablation, microwave ablation, cryotherapy, and localized tumor therapy. The latest developments in the application of minimally invasive therapies in localized neoplastic disease are demonstrated. In the main part of the book, techniques of guiding the applicators to the target structures by use of different imaging tools such as ultrasound, computed tomography and magnetic resonance imaging are discussed. The results are presented for a variety of clinical indications, including liver and lung tumors and metastases and some rather rare conditions involving the kidney, the head and neck, the prostate, and soft tissue structures. A large number of acknowledged experts have contributed to the book, which benefits from a lucid structure and excellent images. (orig.)

  12. Completely thoracoscopic pulmonary vein isolation with ganglionic plexus ablation and left atrial appendage amputation for treatment of atrial fibrillation

    NARCIS (Netherlands)

    A. Yilmaz; G.S.C. Geuzebroek; B.P. van Putte; L.V.A. Boersma; U. Sonker; J.M.T. de Bakker; W.J. van Boven

    2010-01-01

    Objective: Percutaneous catheter pulmonary vein isolation (PVI) has been the preferred choice for invasive treatment of symptomatic, drug-refractory lone atrial fibrillation (AF). Incomplete ablation lines, procedure-related morbidity and long-term success remain, however, a problem. A minimally inv

  13. Case of Successful Mapping of Epicardial Surface of the Basal Part of the Left Ventricle during Ventricular Tachyarrhythmia Radiofrequency Ablation

    Directory of Open Access Journals (Sweden)

    Bockeria L. A.

    2012-09-01

    rhythm and complete elimination of symptomatic ventricular tachyarrhythmiae. Disadvantages of this procedure: possible complications (hemopericardium, precordialgiae, acute myocardial infarction, absence of 100% possibility to use radiofrequency ablation because of supposed arrhythmogenic area of coronary arteries and epicardial body fat; besides, there are the cases of intramyocardial position of ectopic activity.

  14. Evaluation of left ventricular scar identification from contrast enhanced magnetic resonance imaging for guidance of ventricular catheter ablation therapy

    Science.gov (United States)

    Rettmann, M. E.; Lehmann, H. I.; Johnson, S. B.; Packer, D. L.

    2016-03-01

    Patients with ventricular arrhythmias typically exhibit myocardial scarring, which is believed to be an important anatomic substrate for reentrant circuits, thereby making these regions a key target in catheter ablation therapy. In ablation therapy, a catheter is guided into the left ventricle and radiofrequency energy is delivered into the tissue to interrupt arrhythmic electrical pathways. Low bipolar voltage regions are typically localized during the procedure through point-by-point construction of an electroanatomic map by sampling the endocardial surface with the ablation catheter and are used as a surrogate for myocardial scar. This process is time consuming, requires significant skill, and has the potential to miss low voltage sites. This has led to efforts to quantify myocardial scar preoperatively using delayed, contrast-enhanced MRI. In this paper, we evaluate the utility of left ventricular scar identification from delayed contrast enhanced magnetic resonance imaging for guidance of catheter ablation of ventricular arrhythmias. Myocardial infarcts were created in three canines followed by a delayed, contrast enhanced MRI scan and electroanatomic mapping. The left ventricle and myocardial scar is segmented from preoperative MRI images and sampled points from the procedural electroanatomical map are registered to the segmented endocardial surface. Sampled points with low bipolar voltage points visually align with the segmented scar regions. This work demonstrates the potential utility of using preoperative delayed, enhanced MRI to identify myocardial scarring for guidance of ventricular catheter ablation therapy.

  15. 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.

  16. A computational model for exploratory activity of rats with different anxiety levels in elevated plus-maze.

    Science.gov (United States)

    Costa, Ariadne A; Morato, Silvio; Roque, Antonio C; Tinós, Renato

    2014-10-30

    The elevated plus-maze is an apparatus widely used to study the level of anxiety in rodents. The maze is plus-shaped, with two enclosed arms and two open arms, and elevated 50cm from the floor. During a test, which usually lasts for 5min, the animal is initially put at the center and is free to move and explore the entire maze. The level of anxiety is measured by variables such as the percentage of time spent and the number of entries in the enclosed arms. High percentage of time spent at and number of entries in the enclosed arms indicate anxiety. Here we propose a computational model of rat behavior in the elevated plus-maze based on an artificial neural network trained by a genetic algorithm. The fitness function of the genetic algorithm is composed of reward (positive) and punishment (negative) terms, which are incremented as the computational agent (virtual rat) moves in the maze. The punishment term is modulated by a parameter that simulates the effects of different drugs. Unlike other computational models, the virtual rat is built independently of prior known experimental data. The exploratory behaviors generated by the model for different simulated pharmacological conditions are in good agreement with data from real rats.

  17. Lingual tonsil hypertrophy causing severe dysphagia: treatment with plasma-mediated radiofrequency-based ablation (Coblation).

    Science.gov (United States)

    Mowry, Sarah E; Ament, Marvin; Shapiro, Nina L

    2010-03-01

    Lingual tonsil hypertrophy is an uncommon cause of upper aerodigestive tract pathology. We present the case of a 17-year-old boy who developed severe dysphagia and subsequent weight loss as a result of lingual tonsil hypertrophy. He was successfully treated with plasma-mediated radiofrequency-based ablation (Coblation). In the past, traditional surgical procedures for lingual tonsil hypertrophy were difficult to perform and recovery was difficult, but the introduction of Coblation has made lingual tonsillectomy much easier.

  18. The Use of Cryoballoon Ablation in Atrial Fibrillation: Simplifying Pulmonary Vein Isolation?

    Directory of Open Access Journals (Sweden)

    Gian Battista Chierchia, MD

    2010-12-01

    Full Text Available Atrial fibrillation (AF is certainly the most common arrhythmia encountered in clinical practice, reaching epidemic proportions in occidental society. Nowadays, transcatheter ablation using radiofrequency (RF has become a popular technique in the treatment of drug-resistant AF. Since ectopic beats originating from the pulmonary veins (PVs have been shown to be the main trigger initiating AF, electrical isolation of these venous structures has become the goal when performing this procedure.

  19. Radiofrequency ablation for chronic low back pain: A systematic review of randomized controlled trials

    OpenAIRE

    Laura E Leggett; Lesley JJ Soril; Diane L Lorenzetti; Tom Noseworthy; Rodney Steadman; Simrandeep Tiwana; Fiona Clement

    2014-01-01

    BACKGROUND: Radiofrequency ablation (RFA), a procedure using heat to interrupt pain signals in spinal nerves, is an emerging treatment option for chronic low back pain. Its clinical efficacy has not yet been established. OBJECTIVE: To determine the efficacy of RFA for chronic low back pain associated with lumbar facet joints, sacroiliac joints, discogenic low back pain and the coccyx. METHODS: A systematic review was conducted. Medline, EMBASE, PubMed, SPORTDiscus, CINAHL and the Cochrane Lib...

  20. First Experience Of Application Of High-Intensity Focused Ultrasonic Ablation (Hifu) In Prostate Cancer Treatment

    OpenAIRE

    A.V. Stativko; B.I. Blumberg; A.N. Ponukalin; R.N. Fomkin; P.V. Glybochko

    2009-01-01

    The scientific article points out that 40 sessions of HIFU prostate ablation have been performed for estimation of clinical efficiency. Average frequency of influences presents 628±164 impulses; average volume of tissues subjected to influence during one procedure is 33,8±16,3 smi (132 %) of prostate volume; average operation time constitutes 150 minutes (from 90 to 200 minutes). During the operation no complications have been occurred. In the first days after the session of HIFU there was a ...

  1. Radiofrequency Ablation Mapping with Circumferential Catheter for Paroxys-mal Atrial Fibrillation Originating From the Pulmonary Veins

    Institute of Scientific and Technical Information of China (English)

    刘震; 吴书林; 杨平珍; 方咸宏; 李海杰; 陈泗林; 詹贤章; 薛玉梅

    2002-01-01

    Objectives To assessed thefeasibility and effectiveness of electrophysiologicalmapping of pulmonary veins with a circumferential 10-electrode catheter and radiofrequency catheter abla-tion therapy for patients with paroxysmal atrial fibril-lation. Background Standard mapping and ablationof focal sources of atrial fibrillation are associated withvery long procedure times and low efficacy. Mappingand ablation pulmonary veins guide with a circularcatheter could overcome these limitations. Methods16 patients [male 11, female 5, mean age (51 +14.5) years] with paroxysmal atrial fibrillation refrac-tory to antiarrhythmic drugs were included in thisgroup. A circumferential 10-electrode catheter wasused to pulmonary vein mapping during sinus rhythm orCSd pacing to determine the origin of atrial prematurecontractions. When the ablative target pulmonary veinwas found, the pulmonary vein potentials' distributionand activation were assessment pulmonary veins' ostialablation was performed at the segments showing earliestactivation of pulnonary vein potentials. The end pointwas designed: 1 ) elimination of pulmonary vein po-tential; 2) pulmonary vein potential dissociation fromatrial waves; 3) atrial ectopic beats disappear. ResultsA total of 36 pulmonary veins were ablated, in-cluding 16 left superior, 12 right superior, 7 left in-ferior and 1 right inferior. 1 pulmonary vein in 2 pa-tients was ablated, 2 pulmonary veins in 8 patientswere ablated, 3 pulmonary veins were ablated in 5patients and 4 pulmonary veins were ablated in 1 pa-tient. Procedure duration and fluoroscopy time respec-tively were 186.7 _+ 63.8 min and 51.5 + 15.0 min.During the follow-up 1- 12 months, 11 patients(68.7 % ) were free of AF without any antiarrhythmicdrugs, 2 of them were reablation, effective in 3/16(18.7%) and unsuccessful in 2/16 (12.6%) . 2cases recurred with atrial premature, 1 was treated withamiodarone and the other was repeat electrophysiologi-cal mapping and ablation, 5 cases with

  2. 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.

  3. Heading which way? Y-maze chemical assays: not all crustaceans are alike

    Science.gov (United States)

    Kenning, Matthes; Lehmann, Philipp; Lindström, Magnus; Harzsch, Steffen

    2015-09-01

    In a world full of chemicals, many crustaceans rely on elaborate olfactory systems to guide behaviors related to finding food or to assess the presence of conspecifics and predators. We analyzed the responses of the isopod Saduria entomon to a range of stimuli by which the animal is likely to encounter in its natural habitat using a Y-maze bioassay. In order to document the efficiency of the experimental design, the same bioassay was used to test the behavior of the crayfish Procambarus fallax whose ability to track odors is well documented. The crayfish performed well in the Y-maze and were able to locate the source of a food-related odor with high fidelity. The isopod S. entomon reacted indifferently or with aversion to most of the stimuli applied. In 1800 trials, only four out of 15 different stimuli yielded statistically significant results, and only one odorant was found to be significantly attractive. The findings raise several questions whether the stimuli presented and/or the experimental setup used represents an ecologically relevant situation for S. entomon. In each instance, our experiments illustrate that established methods cannot be readily transferred from one species to another.

  4. A novel radial water tread maze tracks age-related cognitive decline in mice

    Directory of Open Access Journals (Sweden)

    Christina Pettan-Brewer

    2013-10-01

    Full Text Available There is currently no treatment and cure for age-related dementia and cognitive impairment in humans. Mice suffer from age-related cognitive decline just as people do, but assessment is challenging because of cumbersome and at times stressful performance tasks. We developed a novel radial water tread (RWT maze and tested male C57BL/6 (B6 and C57BL/6 x Balb/c F1 (CB6F1 mice at ages 4, 12, 20, and 28 months. B6 mice showed a consistent learning experience and memory retention that gradually decreased with age. CB6F1 mice showed a moderate learning experience in the 4 and 12 month groups, which was not evident in the 20 and 28 month groups. In conclusion, CB6F1 mice showed more severe age-related cognitive impairment compared to B6 mice and might be a suitable model for intervention studies. In addition, the RWT maze has a number of operational advantages compared to currently accepted tasks and can be used to assess age-related cognition impairment in B6 and CB6F1 mice as early as 12 months of age.

  5. Path Complexity in Virtual Water Maze Navigation: Differential Associations with Age, Sex, and Regional Brain Volume.

    Science.gov (United States)

    Daugherty, Ana M; Yuan, Peng; Dahle, Cheryl L; Bender, Andrew R; Yang, Yiqin; Raz, Naftali

    2015-09-01

    Studies of human navigation in virtual maze environments have consistently linked advanced age with greater distance traveled between the start and the goal and longer duration of the search. Observations of search path geometry suggest that routes taken by older adults may be unnecessarily complex and that excessive path complexity may be an indicator of cognitive difficulties experienced by older navigators. In a sample of healthy adults, we quantify search path complexity in a virtual Morris water maze with a novel method based on fractal dimensionality. In a two-level hierarchical linear model, we estimated improvement in navigation performance across trials by a decline in route length, shortening of search time, and reduction in fractal dimensionality of the path. While replicating commonly reported age and sex differences in time and distance indices, a reduction in fractal dimension of the path accounted for improvement across trials, independent of age or sex. The volumes of brain regions associated with the establishment of cognitive maps (parahippocampal gyrus and hippocampus) were related to path dimensionality, but not to the total distance and time. Thus, fractal dimensionality of a navigational path may present a useful complementary method of quantifying performance in navigation.

  6. Modafinil and memory: effects of modafinil on Morris water maze learning and Pavlovian fear conditioning.

    Science.gov (United States)

    Shuman, Tristan; Wood, Suzanne C; Anagnostaras, Stephan G

    2009-04-01

    Modafinil has been shown to promote wakefulness and some studies suggest the drug can improve cognitive function. Because of many similarities, the mechanism of action may be comparable to classical psychostimulants, although the exact mechanisms of modafinil's actions in wakefulness and cognitive enhancement are unknown. The current study aims to further examine the effects of modafinil as a cognitive enhancer on hippocampus-dependent memory in mice. A high dose of modafinil (75 mg/kg ip) given before training improved acquisition on a Morris water maze. When given only before testing, modafinil did not affect water maze performance. We also examined modafinil (0.075 to 75 mg/kg) on Pavlovian fear conditioning. A low dose of pretraining modafinil (0.75 mg/kg) enhanced memory of contextual fear conditioning (tested off-drug 1 week later) whereas a high dose (75 mg/kg) disrupted memory. Pretraining modafinil did not affect cued conditioning at any dose tested, and immediate posttraining modafinil had no effect on either cued or contextual fear. These results suggest that modafinil's effects of memory are more selective than amphetamine or cocaine and specific to hippocampus-dependent memory.

  7. Possible anxiolytic effects of taurine in the mouse elevated plus-maze.

    Science.gov (United States)

    Chen, Si Wei; Kong, Wei Xi; Zhang, Yi Jing; Li, Yu Lei; Mi, Xiao Juan; Mu, Xiao Shuo

    2004-08-01

    The effects of taurine, an inhibitory amino acid, on the behavior of male mice were examined in the elevated plus-maze test of anxiety. Acute taurine treatment (60 mg/kg, PO) significantly increased the percentage of time spent in the open arms. Moreover, when taurine was administered daily for seven days and the plus-maze test was conducted 40 minutes after the last administration, a significant increase of the percentage of time in the open arms was observed even at dose of 2.5 mg/kg, however the open arm entries and the total entries were unaffected at any dose tested. In order to get a comprehensive profile of drug action, detailed behavioral analyses were further exerted. Single administration of 60 mg/kg taurine can significantly reduce the total rears. The results suggest that taurine have some anxiolytic-like properties, although its effects seem more limited and are not consistent with those presented by classic anxiolytics, such as diazepam.

  8. Water Associated Zero Maze: A novel rat test for long term traumatic re-experiencing

    Directory of Open Access Journals (Sweden)

    Gilad eRitov

    2014-01-01

    Full Text Available Often, freezing and startle behaviors in the context of a previously experienced stress are taken as an indication of posttraumatic stress disorder (PTSD-like symptoms in rats. However, PTSD is characterized by large individual variations of symptoms. In order to take into consideration the complex and long term distinctive variations in effects of trauma exposure additional behavioral measures are required.The current study used a novel behavioral test, the Water Associated Zero Maze (WAZM. This test was planned to enable a formation of an association between the context of the maze and an underwater trauma or swim stress in order to examine the impact of exposure to the context which immediately precedes a stressful or a traumatic experience on rat's complex behavior. Rats were exposed to the WAZM and immediately after to an underwater trauma or short swim. One month later rats were re-exposed to the context of the WAZM while their behavior was video recorded. Furthermore, c-Fos expression in the amygdala was measured 90 min after this exposure.The results of the current study indicate that the WAZM can be used to discern behavioral changes measured a long time after the actual traumatic or stressful events. Furthermore, the behavioral changes detected were accompanied by changes of c-Fos expression in the amygdala of exposed rats. We suggest that the WAZM can be used to model traumatic memories re-experiencing in rodent models of human stress-related pathologies such as PTSD.

  9. Influence of magnetic field on zebrafish activity and orientation in a plus maze.

    Science.gov (United States)

    Osipova, Elena A; Pavlova, Vera V; Nepomnyashchikh, Valentin A; Krylov, Viacheslav V

    2016-01-01

    We describe an impact of the geomagnetic field (GMF) and its modification on zebrafish's orientation and locomotor activity in a plus maze with four arms oriented to the north, east, south and west. Zebrafish's directional preferences were bimodal in GMF: they visited two arms oriented in opposed directions (east-west) most frequently. This bimodal preference remained stable for same individuals across experiments divided by several days. When the horizontal GMF component was turned 90° clockwise, the preference accordingly shifted by 90° to arms oriented to the north and south. Other modifications of GMF (reversal of both vertical and horizontal GMF components; reversal of vertical component only; and reversal of horizontal component only) did not exert any discernible effect on the orientation of zebrafish. The 90° turn of horizontal component also resulted in a significant increase of fish's locomotor activity in comparison with the natural GMF. This increase became even more pronounced when the horizontal component was repeatedly turned by 90° and back with 1min interval between turns. Our results show that GMF and its variations should be taken into account when interpreting zebrafish's directional preferences and locomotor activity in mazes and other experimental devices. PMID:26589739

  10. Vertical T-maze choice assay for arthropod response to odorants.

    Science.gov (United States)

    Stelinski, Lukasz; Tiwari, Siddharth

    2013-01-01

    Given the economic importance of insects and arachnids as pests of agricultural crops, urban environments or as vectors of plant and human diseases, various technologies are being developed as control tools. A subset of these tools focuses on modifying the behavior of arthropods by attraction or repulsion. Therefore, arthropods are often the focus of behavioral investigations. Various tools have been developed to measure arthropod behavior, including wind tunnels, flight mills, servospheres, and various types of olfactometers. The purpose of these tools is to measure insect or arachnid response to visual or more often olfactory cues. The vertical T-maze olfactometer described here measures choices performed by insects in response to attractants or repellents. It is a high throughput assay device that takes advantage of the positive phototaxis (attraction to light) and negative geotaxis (tendency to walk or fly upward) exhibited by many arthropods. The olfactometer consists of a 30 cm glass tube that is divided in half with a Teflon strip forming a T-maze. Each half serves as an arm of the olfactometer enabling the test subjects to make a choice between two potential odor fields in assays involving attractants. In assays involving repellents, lack of normal response to known attractants can also be measured as a third variable. PMID:23439130

  11. Cognitive enrichment for bottlenose dolphins (Tursiops truncatus): evaluation of a novel underwater maze device.

    Science.gov (United States)

    Clark, Fay E; Davies, Samuel L; Madigan, Andrew W; Warner, Abby J; Kuczaj, Stan A

    2013-01-01

    Cognitive enrichment is gaining popularity as a tool to enhance captive animal well-being, but research on captive cetaceans is lacking. Dolphin cognition has been studied intensively since the 1950s, and several hundred bottlenose dolphins are housed in major zoos and aquaria worldwide, but most dolphin enrichment consists of simple floating objects. The aim of this study was to investigate whether a novel, underwater maze device (UMD) was cognitively enriching for one group of male and one group of female dolphins at Six Flags Discovery Kingdom, CA. The dolphin's task was to navigate a rubber ball through a maze of pipes, towards an exit pipe. We also tested a modification where an edible gelatine ball fell into the pool once the UMD was solved. The UMD was provided to each group between 8 and 11 times over a 4-week period. Male dolphins used the UMD without prior training, whereas females did not use the UMD at all. Two male dolphins solved the UMD 17 times, using a variety of problem-solving strategies. The UMD had no significant effect on circular (repetitive) swimming patterns, but males spent significantly more time underwater when the UMD was present. Males used the UMD significantly more when it contained the rubber ball, but the gelatine ball stimulated social play. The UMD is a safe and practical device for captive dolphins. It now requires further testing on other dolphins, particularly females, to in order to examine whether the sex differences we observed are a general phenomenon. PMID:24018985

  12. Ablation for atrial fibrillation during mitral valve surgery: 1-year results through continuous subcutaneous monitoring.

    Science.gov (United States)

    Bogachev-Prokophiev, Alexandr; Zheleznev, Sergey; Romanov, Alexander; Pokushalov, Evgeny; Pivkin, Alexey; Corbucci, Giorgio; Karaskov, Alexander

    2012-07-01

    Continuous monitoring of cardiac rhythm may play an important role in measuring the true symptomatic/asymptomatic atrial fibrillation (AF) burden and improve the management of anti-arrhythmic and anti-thrombotic therapies. Forty-seven patients with mitral valve disease and longstanding persistent AF (LSPAF) underwent a left atrial maze procedure with bipolar radiofrequency and valve surgery. The follow-up data recorded by an implanted loop recorder were analysed after 3, 6 and 12 months. On discharge, 40 (85.1%) patients were in stable sinus rhythm, as documented by in-office electrocardiography (ECG), 4 (8.5%) were in pacemaker rhythm and 3 (6.4%) were in AF. One (2.1%) patient died after 7 months. On 12-month follow-up examination, 30 (65.2%) patients had an AF burden 0.5%. Two (4.3%) patients with AF recurrences were completely asymptomatic. Among the symptomatic events stored by the patients, only 27.6% was confirmed as genuine AF recurrences according to the concomitant ECG recorded by the implanted loop recorder. A concomitant bipolar maze procedure during mitral valve surgery is effective in treating AF, as proved by detailed 1-year continuous monitoring. PMID:22514258

  13. Alcohol septal ablation in patients with hypertrophic obstructive cardiomyopathy

    DEFF Research Database (Denmark)

    Jensen, Morten K; Prinz, Christian; Horstkotte, Dieter;

    2013-01-01

    The infarction induced by alcohol septal ablation (ASA) may predispose to arrhythmia and sudden cardiac death (SCD).......The infarction induced by alcohol septal ablation (ASA) may predispose to arrhythmia and sudden cardiac death (SCD)....

  14. Deep Dive Topic: Choosing between ablators

    Energy Technology Data Exchange (ETDEWEB)

    Hurricane, O. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Thomas, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Olson, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-07-14

    Recent data on implosions using identical hohlraums and very similar laser drives underscores the conundrum of making a clear choice of one ablator over another. Table I shows a comparison of Be and CH in a nominal length, gold, 575 μm-diameter, 1.6 mg/cc He gas-fill hohlraum while Table II shows a comparison of undoped HDC and CH in a +700 length, gold, 575 μm diameter, 1.6 mg/cc He gas fill hohlraum. As can be seen in the tables, the net integrated fusion performance of these ablators is the same to within error bars. In the case of the undoped HDC and CH ablators, the hot spot shapes of the implosions were nearly indistinguishable for the experiments listed in Table II.

  15. Thermal Ablation Modeling for Silicate Materials

    Science.gov (United States)

    Chen, Yih-Kanq

    2016-01-01

    A thermal ablation model for silicates is proposed. The model includes the mass losses through the balance between evaporation and condensation, and through the moving molten layer driven by surface shear force and pressure gradient. This model can be applied in ablation simulations of the meteoroid or glassy Thermal Protection Systems for spacecraft. Time-dependent axi-symmetric computations are performed by coupling the fluid dynamics code, Data-Parallel Line Relaxation program, with the material response code, Two-dimensional Implicit Thermal Ablation simulation program, to predict the mass lost rates and shape change. For model validation, the surface recession of fused amorphous quartz rod is computed, and the recession predictions reasonably agree with available data. The present parametric studies for two groups of meteoroid earth entry conditions indicate that the mass loss through moving molten layer is negligibly small for heat-flux conditions at around 1 MW/cm(exp. 2).

  16. Ablation therapy for left atrial autonomic modification.

    Science.gov (United States)

    Malcolme-Lawes, Louisa; Sandler, Belinda C; Sikkel, Markus B; Lim, Phang Boon; Kanagaratnam, Prapa

    2016-08-01

    The autonomic nervous system is implicated in the multifactorial pathogenesis of atrial fibrillation (AF) but few studies have attempted neural targeting for therapeutic intervention. We have demonstrated that short bursts of stimulation, at specific sites of left atrial ganglionated plexi (GPs), trigger fibrillation-inducing atrial ectopy and importantly continuous stimulation of these sites may not induce AV block, the 'conventional' marker used to locate GPs. We have shown that these ectopy-triggering GP (ET-GP) sites are anatomically stable and can be rendered inactive by either ablation at the site or by ablation between the site and the adjacent pulmonary vein (PV). This may have important implications for planning patient specific strategies for ablation of paroxysmal AF in the future. PMID:27595199

  17. Interactive Volumetry Of Liver Ablation Zones

    CERN Document Server

    Egger, Jan; Brandmaier, Philipp; Seider, Daniel; Gawlitza, Matthias; Strocka, Steffen; Voglreiter, Philip; Dokter, Mark; Hofmann, Michael; Kainz, Bernhard; Hann, Alexander; Chen, Xiaojun; Alhonnoro, Tuomas; Pollari, Mika; Schmalstieg, Dieter; Moche, Michael

    2015-01-01

    Percutaneous radiofrequency ablation (RFA) is a minimally invasive technique that destroys cancer cells by heat. The heat results from focusing energy in the radiofrequency spectrum through a needle. Amongst others, this can enable the treatment of patients who are not eligible for an open surgery. However, the possibility of recurrent liver cancer due to incomplete ablation of the tumor makes post-interventional monitoring via regular follow-up scans mandatory. These scans have to be carefully inspected for any conspicuousness. Within this study, the RF ablation zones from twelve post-interventional CT acquisitions have been segmented semi-automatically to support the visual inspection. An interactive, graph-based contouring approach, which prefers spherically shaped regions, has been applied. For the quantitative and qualitative analysis of the algorithm's results, manual slice-by-slice segmentations produced by clinical experts have been used as the gold standard (which have also been compared among each o...

  18. Dragging technique versus blanching technique for endometrial ablation with the Nd:YAG laser in the treatment of chronic menorrhagia.

    Science.gov (United States)

    Lomano, J M

    1988-07-01

    Endometrial ablation performed with the Nd:YAG laser was developed to treat patients with chronic menorrhagia as an alternative to hysterectomy. The original dragging technique may result in an obscured operating field and fluid overload. This study compares results of endometrial ablation performed in 62 patients. The first 17 procedures were performed by use of the dragging technique; the last 45 procedures were performed with a blanching technique. Both procedures were performed at the same institution and by the same surgeon. Sixty-five percent of patients undergoing the blanching technique became amenorrheic after the procedure versus 12% of those undergoing the dragging technique. Moreover, the blanching technique required less time, fewer joules of energy, and resulted in less fluid absorption by the patient. The blanching technique is apparently more effective, easier to accomplish, and safer for the patient than the dragging technique.

  19. Radiofrequency ablation of a misdiagnosed Brodie’s abscess

    Science.gov (United States)

    Chan, RS; Abdullah, BJJ; Aik, S; Tok, CH

    2011-01-01

    Radiofrequency ablation (RFA) therapy is recognised as a safe and effective treatment option for osteoid osteoma. This case report describes a 27-year-old man who underwent computed tomography (CT)-guided percutaneous RFA for a femoral osteoid osteoma, which was diagnosed based on his clinical presentation and CT findings. The patient developed worsening symptoms complicated by osteomyelitis after the procedure. His clinical progression and subsequent MRI findings had led to a revised diagnosis of a Brodie’s abscess, which was further supported by the eventual resolution of his symptoms following a combination of antibiotics treatment and surgical irrigations. This case report illustrates the unusual MRI features of osteomyelitis mimicking soft tissue tumours following RFA of a misdiagnosed Brodie’s abscess and highlights the importance of a confirmatory histopathological diagnosis for an osteoid osteoma prior to treatment. PMID:22291860

  20. Radiofrequency catheter ablation of Type 1 atrial flutter using a large-tip electrode catheter and high-power radiofrequency energy generator.

    Science.gov (United States)

    Feld, Gregory K

    2004-11-01

    Recent studies have demonstrated a high degree of efficacy of 8 mm electrode-tipped or saline-irrigated-tip catheters for ablation of atrial flutter (AFL). These catheters have a theoretical advantage as they produce a large ablation lesion. However, large-tip ablation catheters have a larger surface area and require a higher power radiofrequency (RF) generator with up to 100 W capacity to produce adequate ablation temperatures (50-60 degrees C). The potential advantages of a large-tip ablation catheter and high-power RF generator include the need for fewer energy applications, shorter procedure and fluoroscopy times, and greater efficacy. Therefore, the safety and efficacy of AFL ablation using 8 or 10 mm electrode catheters and a 100-W RF generator was studied using the Boston Scientific, Inc., EPT-1000 XP cardiac ablation system. There were 169 patients, aged 61 +/- 12 years involved. Acute end points were bidirectional isthmus block and no inducible AFL. Following ablation, patients were seen at 1, 3 and 6 months, with event monitoring performed weekly and for any symptoms. Three quality of life surveys were completed during follow-up. Acute success was achieved in 158 patients (93%), with 12 +/- 11 RF energy applications. The efficacy of 8 and 10 mm electrodes did not differ significantly. The number of RF energy applications (10 +/- 8 vs. 14 +/- 8) and ablation time (0.5 +/- 0.4 vs. 0.8 +/- 0.6 h) were less with 10 mm compared with 8 mm electrodes (p free of symptoms at 12 and 24 months, respectively. Ablation of AFL improved quality of life scores (p generator was safe, effective and improved quality of life. The number and duration of RF applications was lower with 10 mm compared with 8 mm electrode catheters. PMID:16293039