Extended supraclavicular fasciocutaneous island flap based on the transverse cervical artery for head and neck reconstruction after cancer ablation.

PubMed

Chen, Wei-Liang; Zhang, Da-ming; Yang, Zhao-hui; Huang, Zhi-quan; Wang, Jian-guang; Zhang, Bin; Li, Jing-song

2010-10-01

This clinical study assessed a pedicled supraclavicular fasciocutaneous island flap (SFIF) based on the transverse cervical artery that was extended to include shoulder skin for reconstructing the head and neck. Pedicled SFIFs extended to include the shoulder skin based on the cutaneous feeder vessels and perforator vessels in the deep fascia of the transverse cervical artery were designed for 24 patients with defects of the head and neck after cancer ablation. Preoperative 3-dimensional computed tomographic angiography was performed in all patients. The patients consisted of 15 men and 9 women ranging in age from 24 to 73 years. The primary lesions included squamous cell carcinoma of the tongue, buccal mucosa, floor of the mouth, oropharynx, palate, and lower gingiva. Three-dimensional computed tomographic angiography showed that the transverse cervical artery arose from the thyrocervical trunk in 13 cases and from the subclavian artery in 11 cases. The diameter of the artery ranged from 0.15 to 0.24 cm. The size of flaps ranged from 4 × 8 cm to 6 × 12 cm, and the mean length of the vascular pedicle was approximately 18.5 cm. Of the flaps, 23 survived completely, for a success rate of 95.8%. Three patients underwent radiotherapy, and the follow-up period ranged from 3 to 12 months. One patient died of local tumor recurrence, and cervical recurrences developed in 3 patients. An SFIF extended to include the shoulder skin based on the cutaneous feeder vessels and perforator vessels in the deep fascia of the transverse cervical artery is a useful, viable option for defects of the head and neck after cancer ablation. Copyright © 2010 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Effect of Hashimoto thyroiditis on low-dose radioactive-iodine remnant ablation.

PubMed

Kwon, Hyungju; Choi, June Young; Moon, Jae Hoon; Park, Hyo Jin; Lee, Won Woo; Lee, Kyu Eun

2016-04-01

Radioactive-iodine remnant ablation is an integral part of the papillary thyroid carcinoma (PTC) treatment. Although a minimum dose is usually recommended, there is controversy as to whether the low-dose (1100 MBq) radioactive-iodine remnant ablation is adequate for selected patients. A retrospective cohort study was conducted on 691 patients. Patients with no remnant thyroid on the follow-up whole body scan and low stimulated thyroglobulin (sTg) level (<2.0 ng/mL) were deemed as successful treatment cases. Initial low-dose radioactive-iodine remnant ablation was successful in 431 patients (62.3%). Multivariate analysis demonstrated a negative correlation between successful radioactive-iodine remnant ablation and coexisting Hashimoto thyroiditis based on histopathology diagnosis (odds ratio [OR] = 3.23; p < .001) as well as elevated preablation sTg (OR = 1.24; p < .001). Our data suggest that coexisting Hashimoto thyroiditis and elevated sTg are negative predictive factors for successful low-dose radioactive-iodine remnant ablation treatment. An appropriate risk-adjusted approach may improve the efficacy of radioactive-iodine remnant ablation treatment. © 2015 Wiley Periodicals, Inc. Head Neck 38: E730-E735, 2016. © 2015 Wiley Periodicals, Inc.

Laparoscopic vs computerized tomography-guided radiofrequency ablation for large hepatic hemangiomas abutting the diaphragm

PubMed Central

Gao, Jun; Kong, Jian; Ding, Xue-Mei; Ke, Shan; Niu, Hai-Gang; Xin, Zong-Hai; Ning, Chun-Min; Guo, Shi-Gang; Li, Xiao-Long; Zhang, Long; Dong, Yong-Hong; Sun, Wen-Bing

2015-01-01

AIM: To compare safety and therapeutic efficacy of laparoscopic radiofrequency (RF) ablation vs computed tomography (CT)-guided RF ablation for large hepatic hemangiomas abutting the diaphragm. METHODS: We retrospectively reviewed our sequential experience of treating 51 large hepatic hemangiomas abutting the diaphragm in 51 patients by CT-guided or laparoscopic RF ablation due to either the presence of symptoms and/or the enlargement of hemangioma. Altogether, 24 hemangiomas were ablated via a CT-guided percutaneous approach (CT-guided ablation group), and 27 hemangiomas were treated via a laparoscopic approach (laparoscopic ablation group). RESULTS: The mean diameter of the 51 hemangiomas was 9.6 ± 1.8 cm (range, 6.0-12.0 cm). There was no difference in the diameter of hemangiomas between the two groups (P > 0.05). RF ablation was performed successfully in all patients. There was no difference in ablation times between groups (P > 0.05). There were 23 thoracic complications in 17 patients: 15 (62.5%, 15/24) in the CT-guided ablation group and 2 (7.4%, 2/27) in the laparoscopic ablation group (P < 0.05). According to the Dindo-Clavien classification, two complications (pleural effusion and diaphragmatic rupture grade III) were major in two patients. All others were minor (grade I). Both major complications occurred in the CT-guided ablation group. The minor complications were treated successfully with conservative measures, and the two major complications underwent treatment by chest tube drainage and thoracoscopic surgery, respectively. Complete ablation was achieved in 91.7% (22/24) and 96.3% (26/27) in the CT-guided and the laparoscopic ablation groups, respectively (P > 0.05). CONCLUSION: Laparoscopic RF ablation therapy should be used as the first-line treatment option for large hepatic hemangiomas abutting the diaphragm. It avoids thermal injury to the diaphragm and reduces thoracic complications. PMID:26019459

Laser tumor treatment in oral and maxillofacial surgery

NASA Astrophysics Data System (ADS)

Neukam, F. W.; Stelzle, F.

Cancer treatment is an integral part of oral and maxillofacial surgery. Oral cancer in particular is a highly prevalent neoplasm. Standard treatment for most of the tumors is radical surgery combined with stage-based neo-/adjuvant therapy. Laser surgery has become a reliable treatment option for oral cancer as well as for precancerous lesions. Widely used lasers in oral and maxillofacial tumor surgery are the CO2 laser, the Er:YAG laser, the Nd:YAG laser and the KTM laser. The use of lasers in tumor surgery has several advantages: remote application, precise cutting, hemostasis, low cicatrization, reduced postoperative pain and swelling, can be combined with endoscopic, microscopic and robotic surgery. However, laser surgery has some major drawbacks: In contrast to conventional incisions with scalpels, the surgeon gets no feedback during laser ablation. There is no depth sensation and no tissue specificity with a laser incision, increasing the risk of iatrogenic damage to nerves and major blood vessels. Future prospects may solve these problems by means of an optical feedback mechanism that provides a tissue-specific laser ablation. First attempts have been made to perform remote optical tissue differentiation. Additionally, real time optical tumor detection during laser surgery would allow for a very precise and straight forward cancer resection, enhancing organ preservation and hence the quality of life for patients with cancer in the head and neck region.

Neuropsychologist's (re-)view: Resective versus ablative amygdalohippocampectomies.

PubMed

Witt, Juri-Alexander; Hoppe, Christian; Helmstaedter, Christoph

2018-05-01

Pharmacoresistant mesial temporal lobe epilepsy (mTLE) represents the major indication for epilepsy surgery. Since epilepsy surgery is an elective treatment option, preserving cognition is a high priority. Given the essential role of temporomesial structures in declarative long-term memory formation, surgical treatment for mTLE is primarily associated with a risk of material-specific memory decline, but other cognitive domains may be affected as well. The major determinants for the neuropsychological outcome are the functional integrity of surgically affected tissues, the functional reserve capacities of the remnant brain, the postoperative seizure outcome, as well as the quantitative and qualitative changes of antiepileptic drugs. Anterior temporal lobectomy has long been the standard procedure for treating mTLE. However, if an exclusive mesial pathology is present, then functional non-pathological tissues of the temporal pole and neocortex are sacrificed. As a result, more selective or tailored surgical approaches have been developed which strive towards minimizing iatrogenic effects. However, whether or not these approaches are equipotential with regard to seizure control is still a matter of debate. The quality of the presurgical diagnostics could also be decisive. Selective surgery should indeed be selective in terms of preventing evitable collateral cortical damage along the approach. Invasivity and risks of collateral damage associated with "open" selective resective surgery are further minimized by stereotactic ablative surgery via thermocoagulation, or eventually even eliminated by gamma knife surgery. From a neuropsychological point of view, this development is consequent and desirable, but no clear scientific evidence of a superior cognitive outcome after radiosurgery or thermocoagulation currently exists. The studies that are available contain significant methodological limitations. Thus, randomized head-to-head cognitive outcome studies of competing selective procedures are needed, which should meet the minimum requirements for study design and neuropsychological evaluations. Finally, none of the surgical treatment variants can systematically prevent memory decline when the hippocampus is targeted. Copyright © 2017 Elsevier B.V. All rights reserved.

Irreversible electroporation therapy in the management of locally advanced pancreatic adenocarcinoma.

PubMed

Martin, Robert C G; McFarland, Kelli; Ellis, Susan; Velanovich, Vic

2012-09-01

Locally advanced pancreatic cancer patients have limited options for disease control. Local ablation technologies based on thermal damage have been used but are associated with major complications in this region of the pancreas. Irreversible electroporation (IRE) is a nonthermal ablation technology that we have shown is safe near vital vascular and ductal structures. The aim of this study was to evaluate the safety and efficacy of IRE as a therapy in the treatment of locally advanced pancreatic cancer. We performed a prospective multi-institutional pilot evaluation of patients undergoing IRE for locally advanced pancreatic cancer from December 2009 to March 2011. These patients were evaluated for 90-day morbidity, mortality, and local disease control. Twenty-seven patients (13 women and 14 men) underwent IRE, with median age of 61 years (range 45 to 80 years). Eight patients underwent margin accentuation with IRE in combination with left-sided resection (n = 4) or pancreatic head resection (n = 4). Nineteen patients had in situ IRE. All patients underwent successful IRE, with intraoperative imaging confirming effective delivery of therapy. All 27 patients demonstrated nonclinically relevant elevation of their amylase and lipase, which peaked at 48 hours and returned to normal at 72 hour postprocedure. There has been one 90-day mortality. No patient has shown evidence of clinical pancreatitis or fistula formation. After all patients have completed 90-day follow-up, there has been 100% ablation success. IRE ablation of locally advanced pancreatic cancer tumors is a safe and feasible primary local treatment in unresectable, locally advanced disease. Confirming these early results must occur in a planned phase II investigational device exemption (IDE) study to be initiated in 2012. Copyright © 2012 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

Massive hematemesis after radiofrequency ablation of metastatic liver tumor with successful hemostasis achieved through transarterial embolization.

PubMed

Liu, Chien-An; Chiu, Nai-Chi; Chiou, Yi-You

2018-03-03

Hemorrhagic complications are the most common major complications that occur after radiofrequency ablation, but hematemesis as a complication after radiofrequency ablation for hepatic tumor has not been mentioned before. A hepatogastric fistula as a delayed complication is also rare. We present the case of a 77-year-old man with severe hematemesis that occurred 2 months after radiofrequency ablation of a liver metastasis of gastric cancer. A ruptured hepatic artery pseudoaneurysm and a hepatogastric fistula were confirmed through serial imaging examinations. The current case is reported in combination with 2 rare major complications after radiofrequency ablation of a liver tumor. Copyright © 2018. Published by Elsevier Inc.

Radiofrequency assisted pancreaticoduodenectomy for palliative surgical resection of locally advanced pancreatic adenocarcinoma.

PubMed

Kumar, Jayant; Reccia, Isabella; Sodergren, Mikael H; Kusano, Tomokazu; Zanellato, Artur; Pai, Madhava; Spalding, Duncan; Zacharoulis, Dimitris; Habib, Nagy

2018-03-20

Despite careful patient selection and preoperative investigations curative resection rate (R0) in pancreaticoduodenectomy ranges from 15% to 87%. Here we describe a new palliative approach for pancreaticoduodenectomy using a radiofrequency energy device to ablate tumor in situ in patients undergoing R1/R2 resections for locally advanced pancreatic ductal adenocarcinoma where vascular reconstruction was not feasible. There was neither postoperative mortality nor significant morbidity. Each time the ablation lasted less than 15 minutes. Following radiofrequency ablation it was observed that the tumor remnant attached to the vessel had shrunk significantly. In four patients this allowed easier separation and dissection of the ablated tumor from the adherent vessel leading to R1 resection. In the other two patients, the ablated tumor did not separate from vessel due to true tumor invasion and patients had an R2 resection. The ablated remnant part of the tumor was left in situ. Whenever pancreaticoduodenectomy with R0 resection cannot be achieved, this new palliative procedure could be considered in order to facilitate resection and enable maximum destruction in remnant tumors. Six patients with suspected tumor infiltration and where vascular reconstruction was not warranted underwent radiofrequency-assisted pancreaticoduodenectomy for locally advanced pancreatic ductal adenocarcinoma. Radiofrequency was applied across the tumor vertically 5-10 mm from the edge of the mesenteric and portal veins. Following ablation, the duodenum and the head of pancreas were removed after knife excision along the ablated line. The remaining ablated tissue was left in situ attached to the vessel.

Decreased morbidity and mortality of autologous hematopoietic transplants for children with malignant central nervous system tumors: the 'Head Start' trials, 1991-2009.

PubMed

Altshuler, C; Haley, K; Dhall, G; Vasquez, L; Gardner, S L; Stanek, J; Finlay, J L

2016-07-01

Since 1991, three sequential prospective clinical trials have been conducted by the 'Head Start' (HS) Consortium in which young children with newly-diagnosed malignant central nervous system (CNS) tumors were treated with induction chemotherapy followed by single-cycle marrow-ablative chemotherapy and autologous hematopoietic rescue as a means of improving disease cure rate and quality of survival through avoidance (<6 years old at diagnosis) or reduction (6-10 years old) of brain irradiation. Bone Marrow (HS I) or filgrastim-mobilized peripheral hematopoietic cells (HS II and III) were obtained following recovery from the first and/or second induction cycles. Radiotherapy was administered following all chemotherapy only for patients with residual tumor following completion of induction or with age greater than 6 years at diagnosis. Two hundred and twenty-six children were enrolled on three consecutive HS trials with primary malignant CNS tumors and underwent marrow-ablative chemotherapy. The 100-day treatment-related mortality (TRM) steadily declined as did grade IV transplant-related oropharyngeal mucositis. Factors most likely associated with the decrease in TRM and morbidity are increasing experience with the marrow-ablative chemotherapy regimen combined with improved leukapheresis and post-reinfusion supportive care techniques, contributing toward improved overall survival.

Prosthetic plate mandibular reconstruction.

PubMed

Davidson, M J; Gullane, P J

1991-12-01

The head and neck surgeon may choose one of several available methods to reconstruct the mandible following tumor ablation. This article discusses the use of metallic mandibular prostheses, the indications for alloplastic mandibular reconstruction, techniques of plate application (AO and THRP), and associated complications.

Head and Neck Cancer: An Evolving Treatment Paradigm

PubMed Central

Cognetti, David M.; Weber, Randal S.; Lai, Stephen Y.

2009-01-01

Since the inception of this journal in 1948, the understanding of etiologic factors that contribute to and the treatment of head and neck cancer has evolved dramatically. Advances in surgery, radiation therapy, and chemotherapy have improved locoregional control, survival, and quality of life. The outcomes of these treatment modalities have shifted the focus of curative efforts from radical ablation to preservation and restoration of function. This evolution has been documented in the pages of Cancer for the past 6 decades. This review focuses on the evolution of treatment approaches for head and neck cancer and future directions while recognizing the historic contributions recorded within this journal. PMID:18798532

Patterned femtosecond-laser ablation of Xenopus laevis melanocytes for studies of cell migration, wound repair, and developmental processes

PubMed Central

Mondia, Jessica P.; Adams, Dany S.; Orendorff, Ryan D.; Levin, Michael; Omenetto, Fiorenzo G.

2011-01-01

Ultrafast (femtosecond) lasers have become an important tool to investigate biological phenomena because of their ability to effect highly localized tissue removal in surgical applications. Here we describe programmable, microscale, femtosecond-laser ablation of melanocytes found on Xenopus laevis tadpoles, a technique that is applicable to biological studies in development, regeneration, and cancer research. We illustrate laser marking of individual melanocytes, and the drawing of patterns on melanocyte clusters to help track their migration and/or regeneration. We also demonstrate that this system can upgrade scratch tests, a technique used widely with cultured cells to study cell migration and wound healing, to the more realistic in vivo realm, by clearing a region of melanocytes and monitoring their return over time. In addition, we show how melanocyte ablation can be used for loss-of-function experiments by damaging neighboring tissue, using the example of abnormal tail regeneration following localized spinal cord damage. Since the size, shape, and depth of melanocytes vary as a function of tadpole age and melanocyte location (head or tail), an ablation threshold chart is given. Mechanisms of laser ablation are also discussed. PMID:21833375

Patterned femtosecond-laser ablation of Xenopus laevis melanocytes for studies of cell migration, wound repair, and developmental processes.

PubMed

Mondia, Jessica P; Adams, Dany S; Orendorff, Ryan D; Levin, Michael; Omenetto, Fiorenzo G

2011-08-01

Ultrafast (femtosecond) lasers have become an important tool to investigate biological phenomena because of their ability to effect highly localized tissue removal in surgical applications. Here we describe programmable, microscale, femtosecond-laser ablation of melanocytes found on Xenopus laevis tadpoles, a technique that is applicable to biological studies in development, regeneration, and cancer research. We illustrate laser marking of individual melanocytes, and the drawing of patterns on melanocyte clusters to help track their migration and/or regeneration. We also demonstrate that this system can upgrade scratch tests, a technique used widely with cultured cells to study cell migration and wound healing, to the more realistic in vivo realm, by clearing a region of melanocytes and monitoring their return over time. In addition, we show how melanocyte ablation can be used for loss-of-function experiments by damaging neighboring tissue, using the example of abnormal tail regeneration following localized spinal cord damage. Since the size, shape, and depth of melanocytes vary as a function of tadpole age and melanocyte location (head or tail), an ablation threshold chart is given. Mechanisms of laser ablation are also discussed.

Biophysics and pathology of catheter energy delivery systems.

PubMed

Nath, S; Haines, D E

1995-01-01

Catheter ablation has rapidly emerged as the treatment of choice for many symptomatic cardiac arrhythmias. The initial experience with catheter ablation used high-energy DC as the energy source. However, over the last several years radiofrequency (RF) catheter ablation has become the dominant mode of energy delivery. Currently, a major limitation of RF ablation is the small lesion size created by this technique that has reduced its success rate in ablation of larger arrhythmogenic substrates such as coronary artery disease-related ventricular tachycardia. Alternate energy sources such as microwave or ultrasound catheter ablation are being developed that have the potential for producing larger lesions than RF ablation. This review will discuss the biophysics and pathophysiology of the various energy modalities used in catheter ablation.

Formation of Dense Plasma around a Small Meteoroid: Kinetic Theory and its Implications

NASA Astrophysics Data System (ADS)

Dimant, Y. S.; Oppenheim, M. M.; Marshall, R.

2016-12-01

Every second, millions of small meteoroids hit the Earth from space, the vast majority too small to observe visually. Radars easily detect the plasma generated during meteoroid ablation and use this data to characterize the meteoroids and the atmosphere in which they disintegrate. Reflections of radar pulses from this plasma produce a signal called a head echo. We have developed a first-principle kinetic theory to describe the behavior of meteoric particles ablated from a fast-moving meteoroid and partially ionized through collisions with the atmosphere. This theory produces analytic expressions describing the ion and neutral density and velocity distributions. This analytical model will allow more accurate quantitative interpretations of head echo radar measurements. These, in turn, will improve our ability to infer meteoroid and atmospheric properties. Figure shows the theoretically predicted spatial distribution of the near-meteoroid plasma. This distribution is axially symmetric with respect to the path of the meteoroid. The plasma density within a collisional mean-free-path length drops in proportion to 1/R where R is the distance from the meteoroid center. Beyond this distance and behind the meteoroid, the density transitions to ∝ 1/R². This behavior makes the near-meteoroid plasma overdense to the propagating radar wave in all cases at locations sufficiently close to the meteoroid. Using the FDTD model of Marshall and Close [2015], we use this plasma density distribution to calculate the radar cross section (RCS) from head echoes. Consistent with the results of Marshall and Close [2015], we find that the RCS is given by the cross-section area of the meteor plasma inside which the plasma is overdense - the "overdense area" - as viewed from the radar. Since the distribution derived here is specified by two parameters, this result suggests that the meteor plasma distribution can be specified with two measurements of RCS at different frequencies, as was done by Close et al [2004]. The specification of the meteor plasma distribution then leads to an improved estimate of the parent meteoroid mass, a critical parameter for understanding the global meteoroid flux and deposition in the atmosphere. Work is supported by NSF Grant AGS-1244842.

Factors Influencing Postoperative Complications in Reconstructive Microsurgery for Head and Neck Cancer.

PubMed

Lo, Shih-Lun; Yen, Yu-Hsiu; Lee, Pi-Jung; Liu, Chih-Ho Charles; Pu, Chi-Ming

2017-04-01

The present study aimed to analyze multiple variables and to determine the factors influencing postoperative complications in reconstructive microsurgeries for head and neck cancer. This was a retrospective review of the medical records of patients with head and neck cancer who underwent free flap reconstruction after ablation surgery at the Cathay General Hospital (Taipei, Taiwan) from January 2010 to December 2014. Clinical and surgical procedure-related factors were retrieved from a database and analyzed. Major complications included flap failure and life-threatening events. Minor complications were defined as requiring only routine wound care or conservative treatments. To evaluate group differences, the χ 2 test was applied for categorical variables and the Mann-Whitney U test was used for continuous variables. In total, 158 patients (145 men [91.8%], 13 women [8.2%]) were included in this study. The mean age of the study population was 52.4 years (range, 34 to 84 yr). The mean body mass index (BMI) was 23.71 kg/m 2 . Most patients (93.7%) had a history of cigarette smoking. Some patients had diabetes (20.3%) and hypertension (31.6%). The percentage of patients who underwent radiotherapy before surgery was 19.6%. The percentage whose flap required a salvage operation was 8.9%. The success rate of the microvascular surgeries was 95.6%. The major complication rate was 6.3% and the minor complication rate was 27.8%. No surgical mortality was noted. In these patients, poor nutrition status, indicated by low BMI and low albumin level, was associated with a greater tendency to develop postoperative complications. Patients who had diabetes or who had received radiotherapy before surgery had a high risk for major complications. A large skin paddle seemed to be an influencing factor for minor complications, such as wound dehiscence and superficial loss of flaps. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Parallel processing of embossing dies with ultrafast lasers

NASA Astrophysics Data System (ADS)

Jarczynski, Manfred; Mitra, Thomas; Brüning, Stephan; Du, Keming; Jenke, Gerald

2018-02-01

Functionalization of surfaces equips products and components with new features like hydrophilic behavior, adjustable gloss level, light management properties, etc. Small feature sizes demand diffraction-limited spots and adapted fluence for different materials. Through the availability of high power fast repeating ultrashort pulsed lasers and efficient optical processing heads delivering diffraction-limited small spot size of around 10μm it is feasible to achieve fluences higher than an adequate patterning requires. Hence, parallel processing is becoming of interest to increase the throughput and allow mass production of micro machined surfaces. The first step on the roadmap of parallel processing for cylinder embossing dies was realized with an eight- spot processing head based on ns-fiber laser with passive optical beam splitting, individual spot switching by acousto optical modulation and an advanced imaging. Patterning of cylindrical embossing dies shows a high efficiency of nearby 80%, diffraction-limited and equally spaced spots with pitches down to 25μm achieved by a compression using cascaded prism arrays. Due to the nanoseconds laser pulses the ablation shows the typical surrounding material deposition of a hot process. In the next step the processing head was adapted to a picosecond-laser source and the 500W fiber laser was replaced by an ultrashort pulsed laser with 300W, 12ps and a repetition frequency of up to 6MHz. This paper presents details about the processing head design and the analysis of ablation rates and patterns on steel, copper and brass dies. Furthermore, it gives an outlook on scaling the parallel processing head from eight to 16 individually switched beamlets to increase processing throughput and optimized utilization of the available ultrashort pulsed laser energy.

Prediction of radiofrequency ablation lesion formation using a novel temperature sensing technology incorporated in a force sensing catheter.

PubMed

Rozen, Guy; Ptaszek, Leon; Zilberman, Israel; Cordaro, Kevin; Heist, E Kevin; Beeckler, Christopher; Altmann, Andres; Ying, Zhang; Liu, Zhenjiang; Ruskin, Jeremy N; Govari, Assaf; Mansour, Moussa

2017-02-01

Real-time radiofrequency (RF) ablation lesion assessment is a major unmet need in cardiac electrophysiology. The purpose of this study was to assess whether improved temperature measurement using a novel thermocoupling (TC) technology combined with information derived from impedance change, contact force (CF) sensing, and catheter orientation allows accurate real-time prediction of ablation lesion formation. RF ablation lesions were delivered in the ventricles of 15 swine using a novel externally irrigated-tip catheter containing 6 miniature TC sensors in addition to force sensing technology. Ablation duration, power, irrigation rate, impedance drop, CF, and temperature from each sensor were recorded. The catheter "orientation factor" was calculated using measurements from the different TC sensors. Information derived from all the sources was included in a mathematical model developed to predict lesion depth and validated against histologic measurements. A total of 143 ablation lesions were delivered to the left ventricle (n = 74) and right ventricle (n = 69). Mean CF applied during the ablations was 14.34 ± 3.55g, and mean impedance drop achieved during the ablations was 17.5 ± 6.41 Ω. Mean difference between predicted and measured ablation lesion depth was 0.72 ± 0.56 mm. In the majority of lesions (91.6%), the difference between estimated and measured depth was ≤1.5 mm. Accurate real-time prediction of RF lesion depth is feasible using a novel ablation catheter-based system in conjunction with a mathematical prediction model, combining elaborate temperature measurements with information derived from catheter orientation, CF sensing, impedance change, and additional ablation parameters. Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Functional benefits of implants placed during ablative surgery: A 5-year prospective study on the prosthodontic rehabilitation of 56 edentulous oral cancer patients.

PubMed

Wetzels, Jan Willem; Koole, Ron; Meijer, Gert J; de Haan, Anton F J; Merkx, Matthias A W; Speksnijder, Caroline M

2016-04-01

The timing of placement as well as the functional benefit of interforaminal implants in edentulous patients treated for oral cancer is unclear. Fifty-six patients were recruited at 2 institutions. In 1 institution, interforaminal implants were placed during ablative surgery, the other institution used conventional prosthodontics with optional placement of implants postsurgery (postponed-placement). Masticatory performance, bite force, and subjective masticatory function were assessed before and 6 months, 1 year, and 5 years after surgery. Implant-retained overdentures (IODs) demonstrated the highest bite force and the least problems with solid food and food choice. Masticatory performance was equal for IODs and conventional dentures. After 5 years, IODs from patients in the during-ablative-surgery cohort tend to have higher bite force and masticatory performance than those from patients in the postponed-placement cohort. IODs produce the highest overall masticatory function. Implant placement during ablative surgery seems to be functionally beneficial. © 2016 Wiley Periodicals, Inc. Head Neck 38: E2103-E2111, 2016. © 2016 Wiley Periodicals, Inc.

Length of Barrett's segment predicts failure of eradication in radiofrequency ablation for Barrett's esophagus: a retrospective cohort study.

PubMed

Luckett, Tyler; Allamneni, Chaitanya; Cowley, Kevin; Eick, John; Gullick, Allison; Peter, Shajan

2018-05-21

We aim to investigate factors that may contribute to failure of eradication of dysplastic Barrett's Esophagus among patients undergoing radiofrequency ablation treatment. A retrospective review of patients undergoing radiofrequency ablation for treatment of Barrett's Esophagus was performed. Data analyzed included patient demographics, medical history, length of Barrett's Esophagus, number of radiofrequency ablation sessions, and histopathology. Subsets of patients achieving complete eradication were compared with those not achieving complete eradication. A total of 107 patients underwent radiofrequency ablation for Barrett's Esophagus, the majority white, overweight, and male. Before treatment, 63 patients had low-grade dysplasia, and 44 patients had high-grade dysplasia or carcinoma. Complete eradication was achieved in a majority of patients (57% for metaplasia, and 76.6% for dysplasia). Failure of eradication occurred in 15.7% of patients. The median number of radiofrequency ablation treatments in patients achieving complete eradication was 3 sessions, compared to 4 sessions for failure of eradication (p = 0.06). Barrett's esophagus length of more than 5 cm was predictive of failure of eradication (p < 0.001). Radiofrequency ablation for dysplastic Barrett's Esophagus is a proven and effective treatment modality, associated with a high rate of complete eradication. Our rates of eradication from a center starting an ablation program are comparable to previously published studies. Length of Barrett's segment > 5 cm was found to be predictive of failure of eradication in patients undergoing radiofrequency ablation.

Increased Surgical Site Infection Rates following Clindamycin Use in Head and Neck Free Tissue Transfer.

PubMed

Pool, Christopher; Kass, Jason; Spivack, John; Nahumi, Nadav; Khan, Mohemmed; Babus, Lenard; Teng, Marita S; Genden, Eric M; Miles, Brett A

2016-02-01

The development of surgical site infections (SSIs) can put the viability of free tissue transfer reconstructions at risk, often resulting in considerable postoperative morbidity and prolonged hospitalization. Current antibiotic prophylactic guidelines suggest a first- or second-generation cephalosporin with metronidazole for clean-contaminated cases and recommend clindamycin as an alternative choice in penicillin-allergic patients. This study was designed to examine the rates of postoperative infection associated with prophylactic antibiotic regimens, including patients receiving clindamycin as an alternative due to penicillin allergy. Case series with chart review. Tertiary academic medical center. Patients undergoing major ablative head and neck resection involving the pharynx and oral cavity reconstructed via free tissue transfer. The sample included patients (n = 266) who underwent free tissue transfer involving the oral cavity and pharynx from 2009 to 2014. Data included demographic data, medical comorbidities, anatomic tumor subsite and surgical procedure, and prophylactic antibiotic regimen. SSI data were examined up to 30 days after the initial surgical procedure. Multivariate logistic regression analysis was performed to determine the overall risk for SSI. Culture data were also reviewed. The data indicated that clindamycin was associated with an approximate 4-fold increased risk for SSI (odds ratio, 3.784; 95% confidence interval: 1.367-10.470 [P = .010]) after controlling for possible confounding factors. For patients with a true penicillin allergy, we recommend broader gram-negative coverage with alternative antibiotics, such as cefuroxime, when undergoing free tissue transfer in the head and neck. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2015.

Outcomes of Cryoballoon Ablation in High- and Low-Volume Atrial Fibrillation Ablation Centres: A Russian Pilot Survey

PubMed Central

Mikhaylov, Evgeny N.; Lebedev, Dmitry S.; Pokushalov, Evgeny A.; Davtyan, Karapet V.; Ivanitskii, Eduard A.; Nechepurenko, Anatoly A.; Kosonogov, Alexey Ya.; Kolunin, Grigory V.; Morozov, Igor A.; Termosesov, Sergey A.; Maykov, Evgeny B.; Khomutinin, Dmitry N.; Eremin, Sergey A.; Mayorov, Igor M.; Romanov, Alexander B.; Shabanov, Vitaliy V.; Shatakhtsyan, Victoria; Tsivkovskii, Viktor; Revishvili, Amiran Sh.; Shlyakhto, Evgeny V.

2015-01-01

Purpose. The results of cryoballoon ablation (CBA) procedure have been mainly derived from studies conducted in experienced atrial fibrillation (AF) ablation centres. Here, we report on CBA efficacy and complications resulting from real practice of this procedure at both high- and low-volume centres. Methods. Among 62 Russian centres performing AF ablation, 15 (24%) used CBA technology for pulmonary vein isolation. The centres were asked to provide a detailed description of all CBA procedures performed and complications, if encountered. Results. Thirteen sites completed interviews on all CBAs in their centres (>95% of CBAs in Russia). Six sites were high-volume AF ablation (>100 AF cases/year) centres, and 7 were low-volume AF ablation. There was no statistical difference in arrhythmia-free rates between high- and low-volume centres (64.6 versus 60.8% at 6 months). Major complications developed in 1.5% of patients and were equally distributed between high- and low-volume centres. Minor procedure-related events were encountered in 8% of patients and were more prevalent in high-volume centres. Total event and vascular access site event rates were higher in women than in men. Conclusions. CBA has an acceptable efficacy profile in real practice. In less experienced AF ablation centres, the major complication rate is equal to that in high-volume centres. PMID:26640789

Comparison between whole-body and head and neck neurovascular coils for 3-T magnetic resonance proton resonance frequency shift thermography guidance in the head and neck region.

PubMed

Ginat, Daniel Thomas; Anthony, Gregory J; Christoforidis, Gregory; Oto, Aytekin; Dalag, Leonard; Sammet, Steffen

2018-02-01

The purpose of this study is to compare the image quality of magnetic resonance (MR) treatment planning images and proton resonance frequency (PRF) shift thermography images and inform coil selection for MR-guided laser ablation of tumors in the head and neck region. Laser ablation was performed on an agar phantom and monitored via MR PRF shift thermography on a 3-T scanner, following acquisition of T1-weighted (T1W) planning images. PRF shift thermography images and T2-weighted (T2W) planning images were also performed in the neck region of five normal human volunteers. Signal-to-noise ratios (SNR) and temperature uncertainty were calculated and compared between scans acquired with the quadrature mode body integrated coil and a head and neck neurovascular coil. T1W planning images of the agar phantom produced SNRs of 4.0 and 12.2 for the quadrature mode body integrated coil and head and neck neurovascular coil, respectively. The SNR of the phantom MR thermography magnitude images obtained using the quadrature mode body integrated coil was 14.4 versus 59.6 using the head and neck coil. The average temperature uncertainty for MR thermography performed on the phantom with the quadrature mode body integrated coil was 1.1 versus 0.3 °C with the head and neck coil. T2W planning images of the neck in five human volunteers produced SNRs of 28.3 and 91.0 for the quadrature mode body integrated coil and head and neck coil, respectively. MR thermography magnitude images of the neck in the volunteers obtained using the quadrature mode body integrated coil had a signal-to-noise ratio of 8.3, while the SNR using the head and neck coil was 16.1. The average temperature uncertainty for MR thermography performed on the volunteers with the body coil was 2.5 versus 1.6 °C with the head and neck neurovascular coil. The quadrature mode body integrated coil provides inferior image quality for both basic treatment planning sequences and MR PRF shift thermography compared with a neurovascular coil, but may nevertheless be adequate for clinical purposes.

[Voice acoustic study of plasma radiofrequency ablation for the treatment of laryngeal premalignant lesions].

PubMed

Zang, Y Z; Wan, B L; Jia, X D; Wang, G K

2016-11-01

Objective: To study the voice function effect of low temperature plasma radiofrequency ablation in the treatment of patients with laryngeal premalignant lesions. Method: Fifty cases of laryngeal premalignant lesions were treated with low temperature plasma radiofrequency ablation. All of the patients were examined by electronic laryngoscopy and acoustic analysis(F0，Jitter，Shimmer，NNE，HNR) in 2 weeks,1 month,3 months after surgery. Voice acoustic results were compared with a control group of 50 normal adults for the further analysis. Result: Fifty patients with laryngeal premalignant lesions were treated by low temperature plasma radiofrequency ablation.The result showed that 47 patients(94%)were successfully decannulated without serious complications, such as dyspnea, aphonia and anterior glottic stenosis. Acoustic analysis showed that F0,Jitter,Shimmer and NNE were significantly different from normal 2 weeks after surgery（ P <0.01）.Voice function recovered weakly 1 month after operation（ P <0.05）.There were no significant differences in the vocal parameters between plasma radiofrequency ablation group and control group 3 months after surgery( P >0.05). Conclusion: Radiofrequency coblation was a safe,minimally invasive and effective surgical method and can be widely used to treat laryngeal premalignant lesions．. Copyright© by the Editorial Department of Journal of Clinical Otorhinolaryngology Head and Neck Surgery.

Real-time iterative monitoring of radiofrequency ablation tumor therapy with 15O-water PET imaging.

PubMed

Bao, Ande; Goins, Beth; Dodd, Gerald D; Soundararajan, Anuradha; Santoyo, Cristina; Otto, Randal A; Davis, Michael D; Phillips, William T

2008-10-01

A method that provides real-time image-based monitoring of solid tumor therapy to ensure complete tumor eradication during image-guided interventional therapy would be a valuable tool. The short, 2-min half-life of (15)O makes it possible to perform repeated PET imaging at 20-min intervals at multiple time points before and after image-guided therapy. In this study, (15)O-water PET was evaluated as a tool to provide real-time feedback and iterative image guidance to rapidly monitor the intratumoral coverage of radiofrequency (RF) ablation therapy. Tumor RF ablation therapy was performed on head and neck squamous cell carcinoma (SCC) xenograft tumors (length, approximately 23 mm) in 6 nude rats. The tumor in each animal was ablated with RF (1-cm active size ablation catheter, 70 degrees C for 5 min) twice in 2 separate tumor regions with a 20-min separation. The (15)O-water PET images were acquired before RF ablation and after the first RF and second RF ablations using a small-animal PET scanner. In each PET session, approximately 100 MBq of (15)O-water in 1.0 mL of saline were injected intravenously into each animal. List-mode PET images were acquired for 7 min starting 20 s before injection. PET images were reconstructed by 2-dimensional ordered-subset expectation maximization into single-frame images and dynamic images at 10 s/frame. PET images were displayed and analyzed with software. Pre-RF ablation images demonstrate that (15)O-water accumulates in tumors with (15)O activity reaching peak levels immediately after administration. After RF ablation, the ablated region had almost zero activity, whereas the unablated tumor tissue continued to have a high (15)O-water accumulation. Using image feedback, the RF probe was repositioned to a tumor region with residual (15)O-water uptake and then ablated. The second RF ablation in this new region of the tumor resulted in additional ablation of the solid tumor, with a corresponding decrease in activity on the (15)O-water PET image. (15)O-water PET clearly demonstrated the ablated tumor region, whereas the unablated tumor continued to show high (15)O-water accumulation. (15)O-water imaging shows promise as a tool for on-site, real-time monitoring of image-guided interventional cancer therapy.

Oligodendrocyte ablation affects the coordinated interaction between granule and Purkinje neurons during cerebellum development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Collin, Ludovic; Doretto, Sandrine; Department of Psychiatry and Human Behavior, University of California Irvine, 3226 Gillespie Neuroscience Research Facility, Irvine CA 92697

2007-08-01

Oligodendrocytes (OLs) are the glial cells of the central nervous system (CNS) classically known to be devoted to the formation of myelin sheaths around most axons of the vertebrate brain. We have addressed the role of these cells during cerebellar development, by ablating OLs in vivo. Previous analyses had indicated that OL ablation during the first six postnatal days results into a striking cerebellar phenotype, whose major features are a strong reduction of granule neurons and aberrant Purkinje cells development. These two cell types are highly interconnected during cerebellar development through the production of molecules that help their proliferation, differentiationmore » and maintenance. In this article, we present data showing that OL ablation has major effects on the physiology of Purkinje (PC) and granule cells (GC). In particular, OL ablation results into a reduction of sonic hedgehog (Shh), Brain Derived Neurotrophic Factor (BDNF), and Reelin (Rln) expression. These results indicate that absence of OLs profoundly alters the normal cerebellar developmental program.« less

Low Rates of Major Complications for Radiofrequency Ablation of Atrial Fibrillation Maintained Over 14 Years: A Single Centre Experience of 2750 Consecutive Cases.

PubMed

Voskoboinik, Aleksandr; Sparks, Paul B; Morton, Joseph B; Lee, Geoffrey; Joseph, Stephen A; Hawson, Joshua J; Kistler, Peter M; Kalman, Jonathan M

2018-02-03

Despite technological advances, studies continue to report high complication rates for atrial fibrillation (AF) ablation. We sought to review complication rates for AF ablation at a high-volume centre over a 14-year period and identify predictors of complications. We reviewed prospectively collected data from 2750 consecutive AF ablation procedures at our institution using radiofrequency energy (RF) between January 2004 and May 2017. All cases were performed under general anaesthetic with transoesophageal echocardiography (TEE), 3D-mapping and an irrigated ablation catheter. Double transseptal puncture was performed under TEE guidance. All patients underwent wide antral circumferential isolation of the pulmonary veins (30W anteriorly, 25W posteriorly) with substrate modification at operator discretion. Of 2255 initial and 495 redo procedures, ablation strategies were: pulmonary vein isolation (PVI) only 2097 (76.3%), PVI+lines 368 (13.4%), PVI+posterior wall 191 (6.9%), PVI+cavotricuspid isthmus 277 (10.1%). There were 23 major (0.84%) and 20 minor (0.73%) complications. Cardiac tamponade (five cases - 0.18%) and phrenic nerve palsy (one case - 0.04%) rates were very low. Major vascular complications necessitating surgery or blood transfusion occurred in five patients (0.18%). There were no cases of death, permanent disability, atrio-oesophageal fistulae or symptomatic pulmonary vein (PV) stenosis, although there were five TEE probe-related complications (0.18%). Female gender (OR 2.14; 95% CI 1.07-4.26) but not age >70 (OR 1.01) was the only multivariate predictor of complications. Atrial fibrillation ablation performed at a high-volume centre using RF can be achieved with a low major complication rate in a representative AF population over a sustained period of time. Copyright © 2018 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

A Prospective Randomized Trial of Apixaban Dosing During Atrial Fibrillation Ablation: The AEIOU Trial.

PubMed

Reynolds, Matthew R; Allison, J Scott; Natale, Andrea; Weisberg, Ian L; Ellenbogen, Kenneth A; Richards, Mark; Hsieh, Wen-Hua; Sutherland, Julie; Cannon, Christopher P

2018-05-01

This study sought to determine whether uninterrupted apixaban would have similar rates of bleeding and thromboembolic events as does minimally interrupted apixaban at the time of atrial fibrillation (AF) ablation and to compare those results with rates in historical patients treated with uninterrupted warfarin. The safety, efficacy, and optimal dosing regimen for apixaban at the time of AF ablation are uncertain. This prospective, multicenter clinical trial enrolled 306 patients undergoing catheter ablation for nonvalvular AF and randomized 300 to uninterrupted versus minimally interrupted (holding 1 dose) periprocedural apixaban. A retrospective cohort of patients treated with uninterrupted warfarin at the same centers was matched to the apixaban-treated subjects for comparison. Endpoints included clinically significant bleeding, major bleeding, and nonhemorrhagic stroke or systemic embolism (SE) from the time of ablation through 30 days. There were no stroke or SE events. Clinically significant bleeding occurred in 11.3% of 150 evaluable patients on uninterrupted apixaban and 9.7% of 145 evaluable patients on interrupted apixaban (risk difference: 1.7% [95% confidence interval: -5.5% to 8.8%]; p = NS). Rates of major bleeding were 1.3% with uninterrupted apixaban, and 2.1% with interrupted (risk difference: -0.7%; p = NS). The rates of clinically significant and major bleeding were similar for all apixaban patients combined (10.5% and 1.7%), compared with the matched warfarin group (9.8% and 1.4%). Both uninterrupted and minimally interrupted apixaban at the time of AF ablation were associated with a very low rate of thromboembolic events, and rates of both major (<2%) and clinically significant bleeding were similar to uninterrupted warfarin. (Apixaban Evaluation of Interrupted Or Uninterrupted Anticoagulation for Ablation of Atrial Fibrillation [AEIOU]; NCT02608099). Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Atrial Tachycardias Following Atrial Fibrillation Ablation

PubMed Central

Sághy, László; Tutuianu, Cristina; Szilágyi, Judith

2015-01-01

One of the most important proarrhythmic complications after left atrial (LA) ablation is regular atrial tachycardia (AT) or flutter. Those tachycardias that occur after atrial fibrillation (AF) ablation can cause even more severe symptoms than those from the original arrhythmia prior to the index ablation procedure since they are often incessant and associated with rapid ventricular response. Depending on the method and extent of LA ablation and on the electrophysiological properties of underlying LA substrate, the reported incidence of late ATs is variable. To establish the exact mechanism of these tachycardias can be difficult and controversial but correlates with the ablation technique and in the vast majority of cases the mechanism is reentry related to gaps in prior ablation lines. When tachycardias occur, conservative therapy usually is not effective, radiofrequency ablation procedure is mostly successful, but can be challenging, and requires a complex approach. PMID:25308808

Temporal trends in safety and complication rates of catheter ablation for atrial fibrillation.

PubMed

Muthalaly, Rahul G; John, Roy M; Schaeffer, Benjamin; Tanigawa, Shinichi; Nakamura, Tomofumi; Kapur, Sunil; Zei, Paul C; Epstein, Laurence M; Tedrow, Usha B; Michaud, Gregory F; Stevenson, William G; Koplan, Bruce A

2018-06-01

Atrial fibrillation (AF) ablation is increasingly common, but is associated with potential major complications. Technology, experience, and protocols have evolved significantly in recent times, and may have impacted procedural safety. We sought to compare AF ablation safety profiles, including complication rates and fluoroscopy times in a "modern" versus "historical" cohort. We evaluated consecutive patients undergoing AF ablation from a modern cohort (MC) from 2014 to 2015 and a historic cohort (HC) from 2009 to 2011 for complications. Major complications were categorized according to Heart Rhythm Society guidelines. We included 1,425 patients, 726 in the HC and 699 in the MC. The MC was older, had more OSA and less valvular AF. Fifty-two (3.5%) procedures suffered major complications across the cohorts, with significantly fewer in the MC (5.0% vs. 2.3%, P  =  0.007). The largest reductions were seen in vascular, hemorrhagic, ischemic stroke, and perforation/tamponade related complications. Periprocedural antiplatelets drugs (aHR 2.1 [95 CI 1.1-3.9], P  =  0.02) and force-sensing catheters (aHR 0.4 [95 CI 0.2-0.9], P  =  0.03) were independently related to major complication rates. Direct oral anticoagulants and uninterrupted anticoagulation were not associated with complications. There was a decrease in both fluoroscopy (-17.4 minutes [95 CI 19.2-15.6], P < 0.0001) and radiofrequency ablation times (-561 seconds [95CI -750 to -371], P < 0.0001). The safety profile of AF ablation has improved significantly in less than a decade. © 2018 Wiley Periodicals, Inc.

Study of low-cost fabrication of ablative heat shields

NASA Technical Reports Server (NTRS)

Norwood, L. B.

1972-01-01

The major objectives were accomplished in three tasks: (1) modification of the ablative material composition for ease of fabrication as well as thermal and mechanical performance; (2) scaled-up, simplified, manufacturing techniques which resulted in cost reductions; and (3) the identification of a significant design problem caused by the differential pressure buildup imposed on mechanically attached ablative heat shield panels during launch.

Physics and medical applications of cold atmospheric plasma

NASA Astrophysics Data System (ADS)

Keidar, Michael

2013-09-01

Recent progress in atmospheric plasmas led to the creation of cold plasmas with ion temperature close to room temperature. Varieties of novel plasma diagnostic techniques were applied in a quest to understand physics of cold plasmas. In particular it was established that the streamer head charge is about 108 electrons, the electrical field in the head vicinity is about 107 V/m, and the electron density of the streamer column is about 1019 m3. We have demonstrated the efficacy of cold plasma in a pre-clinical model of various cancer types (lung, bladder, breast, head, neck, brain and skin). Both in-vitro andin-vivo studies revealed that cold plasmas selectively kill cancer cells. We showed that: (a) cold plasma application selectively eradicates cancer cells in vitro without damaging normal cells. (b) Significantly reduced tumor size in vivo. Cold plasma treatment led to tumor ablation with neighbouring tumors unaffected. These experiments were performed on more than 10 mice with the same outcome. We found that tumors of about 5mm in diameter were ablated after 2 min of single time plasma treatment. The two best known cold plasma effects, plasma-induced apoptosis and the decrease of cell migration velocity can have important implications in cancer treatment by localizing the affected area of the tissue and by decreasing metastasic development. In addition, cold plasma treatment has affected the cell cycle of cancer cells. In particular, cold plasmainduces a 2-fold increase in cells at the G2/M-checkpoint in both papilloma and carcinoma cells at ~24 hours after treatment, while normal epithelial cells (WTK) did not show significant differences. It was shown that reactive oxygen species metabolism and oxidative stress responsive genes are deregulated. We investigated the production of reactive oxygen species (ROS) with cold plasma treatment as a potential mechanism for the tumor ablation observed.

The History and Evolution of Surgery on the Vestibular Labyrinth.

PubMed

Naples, James G; Eisen, Marc D

2016-11-01

The history of surgery on the vestibular labyrinth is rich but sparsely documented in the literature. The story begins over a century ago with the labyrinthectomy in an era that consisted exclusively of ablative surgery for infection or vertigo. Improved understanding of vestibular physiology and pathology produced an era of selective ablation and hearing preservation that includes semicircular canal occlusion for benign paroxysmal positional vertigo. An era of restoration began with a discovery of superior semicircular canal dehiscence and its repair. The final era of vestibular replacement is upon us as the possibility of successful prosthetic vestibular implantation becomes reality. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2016.

Use of bipolar radiofrequency catheter ablation in treatment of cardiac arrhythmias.

PubMed

Soucek, Filip; Starek, Zdenek

2018-05-23

Background Arrhythmia management is a complex process involving both pharmacological and non-pharmacological approaches. Radiofrequency ablation is the pillar of non-pharmacological arrhythmia treatment. Unipolar ablation is considered to be the gold standard in the treatment of the majority of arrhythmias; however, its efficacy is limited to specific cases. In particular, the creation of deep or transmural lesions to eliminate intramurally originating arrhythmias remains inadequate. Bipolar ablation is proposed as an alternative to overcome unipolar ablation boundaries. Results Despite promising results gained from in vitro and animal studies showing that bipolar ablation is superior in creating transmural lesions, the use of bipolar ablation in daily clinical practice is limited. Several studies have been published showing that bipolar ablation is effective in the treatment of clinical arrhythmias after failed unipolar ablation, however there is inconsistency regarding safety of bipolar ablation within the available research papers. According to research evidence the most common indications for bipolar ablation use are ventricular originating rhythmic disorders in patients with structural heart disease resistant to standard radiofrequency ablation. Conclusions To allow wider clinical application the efficiency and safety of bipolar ablation need to be verified in future studies. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Viability of full-thickness skin grafts used for correction of cicatricial ectropion of lower eyelid in previously irradiated field in the periocular region

PubMed Central

Kim, Hee Joon; Hayek, Brent; Nasser, Qasiem; Esmaeli, Bita

2013-01-01

Purpose To evaluate the viability of skin grafts used for correction of cicatricial ectropion resulting from previous ablative surgery and radiotherapy for head and neck cancer and to report overall outcomes of cicatricial ectropion repair. Methods This is a retrospective, non-comparative case series of all consecutive head and neck cancer patients who had been exposed to high-dose radiation therapy in their periocular region and had surgical correction of their lower eyelid cicatricial ectropion through placement of a full-thickness skin graft and a lower eyelid tightening procedure by the same surgeon. The primary outcome measure was skin graft viability. Secondary outcome measures comprised of post-operative complications, the overall outcome of ectropion repair as judged by improvement in symptoms of exposure keratopathy and dependence on lubricating eye drops and ointments, as well as cosmetic improvement measured through a grading scale determined based on the degree of inferior scleral show and/or tarsal conjunctival eversion. Results 25 patients were eligible for the study. 19 men and 6 women had a median age of 63 years (range: 20–84 years). All 25 patients had high-dose radiation therapy for their head and neck cancer. All but 1 patient had major cancer ablative surgery performed prior to radiation therapy. Thirteen of 25 patients also received chemotherapy. There was 100% viability of the skin grafts used for the repair of lower eyelid cicatricial ectropion. There were a few post-operative complications including the need for revision surgery to correct residual ectropion in the lower eyelid in 2 patients and a third patient required a revision surgery due to upper lid retraction and lagophthalmos after harvest of skin graft from the upper eyelid. Improvement was noted in the subjective symptoms in 22 of 25 patients (88%) while 17 patients (68%) were noted to have improvement in their clinical findings on slit lamp examination. All 20 patients for whom good quality photos were available had improvement in the degree of cicatrical lower eyelid ectropion as measured by the amount of inferior scleral show and tarsal conjunctival eversion, although 11 patients had some residual ectropion. All 20 had either good or excellent result in the appearance of their skin grafts. Conclusions Our findings suggest that full thickness skin grafts are a nice option for correction of cicatricial lower eyelid ectropion in a previously radiated field; 100% of the grafts survived. The majority of patients had improvement of ocular surface damage and symptoms, with a decreased dependence on topical lubricants. All evaluable patients had improvement in the degree of cicatrical lower eyelid ectropion, although close to one-half of patients had some mild residual ectropion. The majority of patients had excellent appearance of the skin graft. PMID:22287483

Simultaneous Optical and Meteor Head Echo Measurements Using the Middle Atmosphere Alomar Radar System (MAARSY)

NASA Technical Reports Server (NTRS)

Cooke, W. J.; Brown, P. G.; Stober, G.; Schult, C.; Krzeminski, Z.; Chau, J. L.

2017-01-01

We describe a two year campaign of simultaneous automated meteor optical and head echo radar measurements conducted with the Middle Atmosphere Alomar Radar System (MAARSY). This campaign was established with the following goals: Compare trajectories as measured by MAARSY and the two optical stations for a range of meteoroid masses. Compare photometric and dynamic mass measured optically with radar-derived masses (inter-calibration of mass scales). Use the best observed simultaneous events to fuse all metric, photometric and ionization estimates together and apply different ablation models to self-consistently model these highest quality events.

Quadriplegia secondary to cervical spondylotic myelopathy-a rare complication of head and neck surgery.

PubMed

Chen, Wei-Fan; Kang, Chung-Jan; Lee, Sai-Cheung; Tsao, Chung-Kan

2013-02-01

Free tissue reconstruction after ablation of head and neck malignancy often requires extensive cervical manipulation, which may exacerbate preexisting cervical spondylosis and result in progression to cervical myelopathy. We present a rare case of postoperative quadriplegia caused by cervical spondylotic myelopathy after head and neck reconstruction. A 63-year-old man without a history of cervical spondylosis underwent resection of a gingivo-buccal squamous cell carcinoma with immediate reconstruction with free fibula osteocutaneous flap. On postoperative day 4, the patient was found to have quadriplegia. MRI demonstrated severe cervical myelopathy. Decompressive laminectomy was performed. The patient underwent an extensive rehabilitation program but only realized moderate improvement. Cervical spondylotic myelopathy is a rare but disastrous complication of head and neck surgery. We hypothesize that it is potentially avoidable with heightened awareness of this disease entity, preoperative identification of patients at risk, and prophylactic interventions Copyright © 2011 Wiley Periodicals, Inc.

Image-Guided Radiofrequency Ablation (RFA) of Unresectable Hepatic Tumors Using a Triple-Spiral-Shaped Electrode Needle: Initial Experience in 34 Patients

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thanos, Loukas; Poulou, Loukia S., E-mail: ploukia@hotmail.co; Ziakas, Panayiotis D.

We evaluated the safety and efficacy of image-guided radiofrequency ablation (RFA) using a triple-spiral-shaped electrode needle for unresectable primary or metastatic hepatic tumors. Thirty-four patients with 46 index tumors were treated. Ablation zone, morbidity, and complications were assessed. The lesions were completely ablated with an ablative margin of about 1 cm. Five patients (14.7%) with a lesion larger than 4.5 cm had local tumor progression after 1 month and were retreated. Hemothorax, as a major complication, occurred in 1 of 34 patients (3.0%) or 1 of 46 lesions ablated (2.2%). RFA using this new electrode needle can be effective inmore » the treatment of large unresectable hepatic tumors.« less

Comparison of remote magnetic navigation ablation and manual ablation of idiopathic ventricular arrhythmia after failed manual ablation.

PubMed

Kawamura, Mitsuharu; Scheinman, Melvin M; Tseng, Zian H; Lee, Byron K; Marcus, Gregory M; Badhwar, Nitish

2017-01-01

Catheter ablation for idiopathic ventricular arrhythmia (VA) is effective and safe, but efficacy is frequently limited due to an epicardial origin and difficult anatomy. The remote magnetic navigation (RMN) catheter has a flexible catheter design allowing access to difficult anatomy. We describe the efficacy of the RMN for ablation of idiopathic VA after failed manual ablation. Among 235 patients with idiopathic VA referred for catheter ablation, we identified 51 patients who were referred for repeat ablation after a failed manual ablation. We analyzed the clinical characteristics, including the successful ablation site and findings at electrophysiology study, in repeat procedures conducted using RMN as compared with manual ablation. Among these patients, 22 (43 %) underwent repeat ablation with the RMN and 29 (57 %) underwent repeat ablation with a manual ablation. Overall, successful ablation rate was significantly higher using RMN as compared with manual ablation (91 vs. 69 %, P = 0.02). Fluoroscopy time in the RMN was 17 ± 12 min as compared with 43 ± 18 min in the manual ablation (P = 0.009). Successful ablation rate in the posterior right ventricular outflow tract (RVOT) plus posterior-tricuspid annulus was higher with RMN as compared with manual ablation (92 vs. 50 %, P = 0.03). Neither groups exhibited any major complications. The RMN is more effective in selected patients with recurrent idiopathic VA after failed manual ablation and is associated with less fluoroscopy time. The RMN catheters have a flexible design enabling them to access otherwise difficult anatomy including the posterior tricuspid annulus and posterior RVOT.

The Safety and Efficacy of Irreversible Electroporation for Large Hepatocellular Carcinoma.

PubMed

Zeng, Jianying; Liu, Guifeng; Li, Zhong-Hai; Yang, Yi; Fang, Gang; Li, Rong-Rong; Xu, Ke-Cheng; Niu, Lizhi

2017-02-01

This study aimed to investigate the safety and effectiveness of irreversible electroporation ablation for unresectable large liver cancer. Fourteen patients were enrolled: 8 with large hepatocellular carcinoma (tumor diameter: 5.1-11.5 cm) and 6 with medium hepatocellular carcinoma (tumor diameter: 3.0-4.1 cm). All patients received percutaneous irreversible electroporation ablation. Ablation time and the incidence of complications were assessed by a t test. Post-irreversible electroporation and regular contrast-enhanced computerized tomography scans were performed to investigate the effect of tumor size (large vs medium) on irreversible electroporation treatment efficacy; 4-table data were assessed using a Fisher exact test. The 14 patients completed irreversible electroporation ablation successfully. In the large hepatocellular carcinoma group, no major complications occurred in the perioperative period. Minor complications comprised bloating, hypokalemia, edema, low white blood cells, and blood clotting abnormalities. All complications were mild and improved after symptomatic treatment. The frequency of minor complications was not significantly different ( P > .05) compared with the medium hepatocellular carcinoma group. The average follow-up time was 2.8 ± 2.1 months and complete ablation was achieved in 25% (2/8; residual = 75%). For the patients with medium hepatocellular carcinoma, the mean follow-up time was 4.3 ± 3.2 months; the rate of complete ablation was 66.6% (4/6; residual rate = 33.3%). The complete ablation rate was not statistically different between the 2 groups ( P > .05). Irreversible electroporation ablation for unresectable large hepatocellular carcinoma is safe, with no major complications. Short-term efficacy is relatively good; however, long-term efficacy remains to be explored.

RN12 and RN30 Epidote anlayses

DOE Data Explorer

Andrew Fowler

2015-01-01

Results for laser ablation measurement of reare earth elments and electron microprobe analysis of major elments in hydrothermal epidote. Laser ablation measurements were completed using an Agilent 7700 quadrupole ICP-MS coupled with 193nm Photon Instruments Excimer laser.

Magneto-absorption effects in magnetic-field assisted laser ablation of silicon by UV nanosecond pulses

NASA Astrophysics Data System (ADS)

Farrokhi, H.; Gruzdev, V.; Zheng, H. Y.; Rawat, R. S.; Zhou, W.

2016-06-01

A constant magnetic field can significantly improve the quality and speed of ablation by nanosecond laser pulses. These improvements are usually attributed to the confinement of laser-produced plasma by the magnetic field and specific propagation effects in the magnetized plasma. Here we report a strong influence of constant axial magnetic field on the ablation of silicon by 20-ns laser pulses at wavelength 355 nm, which results in an increase of ablation depth by a factor of 1.3 to 69 depending on laser parameters and magnitude of the magnetic field. The traditional plasma effects do not explain this result, and magneto-absorption of silicon is proposed as one of the major mechanisms of the significant enhancement of ablation.

The magnetic navigation system allows safety and high efficacy for ablation of arrhythmias.

PubMed

Bauernfeind, Tamas; Akca, Ferdi; Schwagten, Bruno; de Groot, Natasja; Van Belle, Yves; Valk, Suzanne; Ujvari, Barbara; Jordaens, Luc; Szili-Torok, Tamas

2011-07-01

We aimed to evaluate the safety and long-term efficacy of the magnetic navigation system (MNS) in a large number of patients. The MNS has the potential for improving safety and efficacy based on atraumatic catheter design and superior navigation capabilities. In this study, 610 consecutive patients underwent ablation. Patients were divided into two age- and sex-matched groups. Ablations were performed either using MNS (group MNS, 292) or conventional manual ablation [group manual navigation (MAN), 318]. The following parameters were analysed: acute success rate, fluoroscopy time, procedure time, complications [major: pericardial tamponade, permanent atrioventricular (AV) block, major bleeding, and death; minor: minor bleeding and temporary AV block]. Recurrence rate was assessed during follow-up (15±9.5 months). Subgroup analysis was performed for the following groups: atrial fibrillation, isthmus dependent and atypical atrial flutter, atrial tachycardia, AV nodal re-entrant tachycardia, circus movement tachycardia, and ventricular tachycardia (VT). Magnetic navigation system was associated with less major complications (0.34 vs. 3.2%, P=0.01). The total numbers of complications were lower in group MNS (4.5 vs. 10%, P=0.005). Magnetic navigation system was equally effective as MAN in acute success rate for overall groups (92 vs. 94%, P=ns). Magnetic navigation system was more successful for VTs (93 vs. 72%, P<0.05). Less fluoroscopy was used in group MNS (30±20 vs. 35±25 min, P<0.01). There were no differences in procedure times and recurrence rates for the overall groups (168±67 vs. 159±75 min, P=ns; 14 vs. 11%, P=ns; respectively). Our data suggest that the use of MNS improves safety without compromising efficiency of ablations. Magnetic navigation system is more effective than manual ablation for VTs.

Primary malignant tumours of the bony pelvis: US-guided high intensity focused ultrasound ablation.

PubMed

Wang, Yang; Wang, Wei; Tang, Jie

2013-11-01

The aim of this review is to evaluate the value of ultrasound (US)-guided high intensity focused ultrasound (HIFU) ablation in the treatment of primary malignant tumours of the bony pelvis. Eleven patients with primary malignant tumours of the bony pelvis received US-guided HIFU ablation. The maximum tumour size ranged from 5.6 to 25.0 cm (median 10.5 cm). Treatment was curative in four patients and palliative in seven patients. During follow-up, the effectiveness of HIFU ablation was assessed by contrast-enhanced magnetic resonance (MR). Significant coagulative necrosis was obtained in all patients after scheduled HIFU ablations; the volume ablation ratio was 86.7% ± 12.5% (range 65-100%). Complete tumour necrosis was achieved in all patients receiving curative HIFU ablation. No major complications were encountered. No patients died of local tumour progression during follow-up. US-guided HIFU ablation may be a safe and effective minimally invasive technique for the local treatment of primary malignant tumours of the bony pelvis.

Effect of ZrO2 Powders on the Pyrolysis of Polycarbosilanes Coating Under Laser Ablation

NASA Astrophysics Data System (ADS)

Cheng, Han; Chen, Zhaofeng; Tao, Jie; Yan, Bo; Li, Cong; Wang, Liangbing; Zhang, Ying; Fang, Dan; Wan, Shuicheng; Wu, Wangping

Aircrafts hold the outstanding mastery of the sky in modern wars, however the laser beam weapons can carry out laser attacking to aircrafts. The purpose of the present paper is to research on a new type laser protective material. Polycarbosilanes (PCS)/divinylbenzene mixtures containing ZrO2 powders were brushed to the surface of the aluminum alloy plates and then cured at 150°C for 6 h. The PCS-coated plates were ablated by laser for 3 s. The phase identification of as-ablated powders was examined by X-ray diffraction. The results indicated that the as-ablated powders of cured PCS were composed of major phase β-SiC and smaller amounts of free carbon. The PCS composite coating played a certain role of laser ablation resistance. The effect of added ZrO2 powders on the pyrolysis of PCS-coating under laser ablation is conspicuous.

Technical success, technique efficacy and complications of minimally-invasive imaging-guided percutaneous ablation procedures of breast cancer: A systematic review and meta-analysis.

PubMed

Mauri, Giovanni; Sconfienza, Luca Maria; Pescatori, Lorenzo Carlo; Fedeli, Maria Paola; Alì, Marco; Di Leo, Giovanni; Sardanelli, Francesco

2017-08-01

To systematically review studies concerning imaging-guided minimally-invasive breast cancer treatments. An online database search was performed for English-language articles evaluating percutaneous breast cancer ablation. Pooled data and 95% confidence intervals (CIs) were calculated. Technical success, technique efficacy, minor and major complications were analysed, including ablation technique subgroup analysis and effect of tumour size on outcome. Forty-five studies were analysed, including 1,156 patients and 1,168 lesions. Radiofrequency (n=577; 50%), microwaves (n=78; 7%), laser (n=227; 19%), cryoablation (n=156; 13%) and high-intensity focused ultrasound (HIFU, n=129; 11%) were used. Pooled technical success was 96% (95%CI 94-97%) [laser=98% (95-99%); HIFU=96% (90-98%); radiofrequency=96% (93-97%); cryoablation=95% (90-98%); microwave=93% (81-98%)]. Pooled technique efficacy was 75% (67-81%) [radiofrequency=82% (74-88); cryoablation=75% (51-90); laser=59% (35-79); HIFU=49% (26-74)]. Major complications pooled rate was 6% (4-8). Minor complications pooled rate was 8% (5-13%). Differences between techniques were not significant for technical success (p=0.449), major complications (p=0.181) or minor complications (p=0.762), but significant for technique efficacy (p=0.009). Tumour size did not impact on variables (p>0.142). Imaging-guided percutaneous ablation techniques of breast cancer have a high rate of technical success, while technique efficacy remains suboptimal. Complication rates are relatively low. • Imaging-guided ablation techniques for breast cancer are 96% technically successful. • Overall technique efficacy rate is 75% but largely inhomogeneous among studies. • Overall major and minor complication rates are low (6-8%).

Clinical and pathological outcomes after irreversible electroporation of the pancreas using two parallel plate electrodes: a porcine model.

PubMed

Rombouts, Steffi J E; van Dijck, Willemijn P M; Nijkamp, Maarten W; Derksen, Tyche C; Brosens, Lodewijk A A; Hoogwater, Frederik J H; van Leeuwen, Maarten S; Borel Rinkes, Inne H M; van Hillegersberg, Richard; Wittkampf, Fred H; Molenaar, Izaak Q

2017-12-01

Irreversible electroporation (IRE) by inserting needles around the tumor as treatment for locally advanced pancreatic cancer entails several disadvantages, such as incomplete ablation due to field inhomogeneity, technical difficulties in needle placement and a risk of pancreatic fistula development. This experimental study evaluates outcomes of IRE using paddles in a porcine model. Six healthy pigs underwent laparotomy and were treated with 2 separate ablations (in head and tail of the pancreas). Follow-up consisted of clinical and laboratory parameters and contrast-enhanced computed tomography (ceCT) imaging. After 2 weeks, pancreatoduodenectomy was performed for histology and the pigs were terminated. All animals survived 14 days. None of the animals developed signs of infection or significant abdominal distention. Serum amylase and lipase peaked at day 1 postoperatively in all pigs, but normalized without signs of pancreatitis. On ceCT-imaging the ablation zone was visible as an ill-defined, hypodense lesion. No abscesses, cysts or ascites were seen. Histology showed a homogenous fibrotic lesion in all pigs. IRE ablation of healthy porcine pancreatic tissue using two plate electrodes is feasible and safe and creates a homogeneous fibrotic lesion. IRE-paddles should be tested on pancreatic adenocarcinoma to determine the effect in cancer tissue. Copyright © 2017. Published by Elsevier Ltd.

Apixaban versus Warfarin for the Prevention of Periprocedural Cerebral Thromboembolism in Atrial Fibrillation Ablation: Multicenter Prospective Randomized Study.

PubMed

Kuwahara, Taishi; Abe, Mitsunori; Yamaki, Masaru; Fujieda, Hiroyuki; Abe, Yumiko; Hashimoto, Katsushi; Ishiba, Misako; Sakai, Hirotsuka; Hishikari, Keiichi; Takigawa, Masateru; Okubo, Kenji; Takagi, Katsumasa; Tanaka, Yasuaki; Nakajima, Jun; Takahashi, Atsushi

2016-05-01

Stroke can be a life-threatening complication of atrial fibrillation (AF) catheter ablation. Uninterrupted warfarin treatment contributes to minimizing the risk of stroke complications. This was a prospective, open-label, randomized, multicenter study assessing the safety and efficacy of apixaban for the prevention of cerebral thromboembolism complicating AF catheter ablation. Two hundred patients with drug-resistant AF were equally assigned to take either apixaban (5 mg or 2.5 mg twice daily) or warfarin (target international normalized ratio, 2-3) for at least 1 month before AF ablation. Neither drug regimen was interrupted throughout the operative period. Diffusion-weighted magnetic resonance imaging was performed for all patients to detect silent cerebral infarction (SCI) after the ablation. Primary outcomes were defined as the occurrence of stroke, transient ischemic attack, SCI, or major bleeding that required intervention. The secondary outcome was minor bleeding. The groups did not statistically differ in patients' backgrounds or procedural parameters. During AF ablation, the apixaban group required administration of more heparin to maintain an activated clotting time > 300 seconds than the warfarin group (apixaban, 14,000 ± 4,000 units; warfarin, 9,000 ± 3,000 units). Three primary outcome events occurred in each group (apixaban, 2 SCI and 1 major bleed; warfarin, 3 SCI, P = 1.00), and 3 and 4 secondary outcome events occurred in the apixaban and warfarin groups (P = 0.70), respectively. Apixaban has similar safety and effectiveness to warfarin for the prevention of cerebral thromboembolism during the periprocedural period of AF ablation. © 2016 Wiley Periodicals, Inc.

Is Cryoballoon Ablation Preferable to Radiofrequency Ablation for Treatment of Atrial Fibrillation by Pulmonary Vein Isolation? A Meta-Analysis

PubMed Central

Xu, Junxia; Huang, Yingqun; Cai, Hongbin; Qi, Yue; Jia, Nan; Shen, Weifeng; Lin, Jinxiu; Peng, Feng; Niu, Wenquan

2014-01-01

Objective Currently radiofrequency and cryoballoon ablations are the two standard ablation systems used for catheter ablation of atrial fibrillation; however, there is no universal consensus on which ablation is the optimal choice. We therefore sought to undertake a meta-analysis with special emphases on comparing the efficacy and safety between cryoballoon and radiofrequency ablations by synthesizing published clinical trials. Methods and Results Articles were identified by searching the MEDLINE and EMBASE databases before September 2013, by reviewing the bibliographies of eligible reports, and by consulting with experts in this field. Data were extracted independently and in duplicate. There were respectively 469 and 635 patients referred for cryoballoon and radiofrequency ablations from 14 qualified clinical trials. Overall analyses indicated that cryoballoon ablation significantly reduced fluoroscopic time and total procedure time by a weighted mean of 14.13 (95% confidence interval [95% CI]: 2.82 to 25.45; P = 0.014) minutes and 29.65 (95% CI: 8.54 to 50.77; P = 0.006) minutes compared with radiofrequency ablation, respectively, whereas ablation time in cryoballoon ablation was nonsignificantly elongated by a weighted mean of 11.66 (95% CI: −10.71 to 34.04; P = 0.307) minutes. Patients referred for cryoballoon ablation had a high yet nonsignificant success rate of catheter ablation compared with cryoballoon ablation (odds ratio; 95% CI; P: 1.34; 0.53 to 3.36; 0.538), and cryoballoon ablation was also found to be associated with the relatively low risk of having recurrent atrial fibrillation (0.75; 0.3 to 1.88; 0.538) and major complications (0.46; 0.11 to 1.83; 0.269). There was strong evidence of heterogeneity and low probability of publication bias. Conclusion Our findings demonstrate greater improvement in fluoroscopic time and total procedure duration for atrial fibrillation patients referred for cryoballoon ablation than those for radiofrequency ablation. PMID:24587324

CT-guided bipolar and multipolar radiofrequency ablation (RF ablation) of renal cell carcinoma: specific technical aspects and clinical results.

PubMed

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

2013-06-01

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. 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. Bipolar RF ablation was performed in 12 procedures and multipolar RF ablation in 16 procedures (2 applicators in 14 procedures and 3 applicators in 2 procedures). One ablation cycle was performed in 15 procedures and two ablation cycles in 13 procedures. Overall ablation time and deployed energy were 35.0 ± 13.6 min and 43.7 ± 17.9 kJ. Technical success rate was 100 %. Major and minor complication rates were 4 and 14 %. At an imaging follow-up of 15.2 ± 8.8 months, local recurrence-free survival was 14.4 ± 8.8 months and local tumor control rate was 93 %. GFR did not deteriorate after RF ablation (50.8 ± 16.6 ml/min/1.73 m(2) before RF ablation vs. 47.2 ± 11.9 ml/min/1.73 m(2) after RF ablation; not significant). 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.

Continuous and pulsed laser high power beam combiner for additive manufacturing applications

NASA Astrophysics Data System (ADS)

Bassignana, Marta; Califano, Alessio; Pescarmona, Francesco; Braglia, Andrea; Perrone, Guido

2018-02-01

Laser-based additive manufacturing (AM) from metal powders is emerging as the new industrial revolution, although current fabrication approaches still require long mechanical post-processing to improve the final surface quality and meet the design tolerances. To overcome this limitation, the next generation machines are expected to complement laser AM with laser ablation (LA) to implement surface finishing and micro texturing already during the device growth process. With this aim, a new beam combiner to allow the real-time interchange of additive and subtractive processes using the same scanner head has been designed. Extensive tests have been carried out using a 6 kW continuous-wave laser similar to that used for the metal powder fusion and a nanosecond 100W pulsed source similar to that used for laser ablation.

Head and Neck Cancer: An Overview

PubMed Central

Stepnick, David; Gilpin, David

2010-01-01

Ablative surgery for malignancies of the upper aerodigestive tract is the most common reason why the reconstructive surgeon is called upon to reconstruct adult head and neck defects. An understanding of the pathophysiology and treatment of head and neck malignancy is vital to the reconstructive surgeon so that restoration of both form and function can be achieved. It is important to understand the behavior of cancers of each head and neck subsite, as staging and ultimately the treatment of tumors from each subsite is different. Historically, the standard treatment of head and neck cancer was surgery and/or primary radiation therapy with surgical salvage for failure. Beginning in the 1980s, advances in chemotherapy and concurrent delivery with radiation offered new options to standard surgical therapy. Over the past two decades, the concept of organ preservation using chemotherapy together with radiation therapy has been definitively established. Yet, even with the strides made over these two decades with chemoradiation, surgical treatment of head and neck cancer and reconstruction thereof will be an important treatment option for the foreseeable future. Therefore, the relationship between the extirpative and reconstructive surgeon is vital, and a clear understanding of the biology and behavior of head and neck malignancy is crucial to successful patient outcomes. PMID:22550431

High precision laser sclerostomy

NASA Astrophysics Data System (ADS)

Góra, W. S.; Urich, A.; McIntosh, L.; Carter, R. M.; Wilson, C. G.; Dhillon, B.; Hand, D. P.; Shephard, J. D.

2015-03-01

Ultrafast lasers offer a possibility of removing soft ophthalmic tissue without introducing collateral damage at the ablation site or in the surrounding tissue. The potential for using ultrashort pico- and femtosecond pulse lasers for modification of ophthalmic tissue has been reported elsewhere and has resulted in the introduction of new, minimally invasive procedures into clinical practice. Our research aims to define the most efficient parameters to allow for the modification of scleral tissue without introducing collateral damage. Our experiments were carried out on hydrated porcine sclera in vitro. Porcine sclera, which has similar collagen organization, histology and water content (~70%) to human tissue was used. Supporting this work we present a 2D finite element blow-off model which employs a one-step heating process. It is assumed that the incident laser radiation that is not reflected is absorbed in the tissue according to the Beer-Lambert law and transformed into heat energy. The experimental setup uses an industrial picosecond laser (TRUMPF TruMicro 5x50) with 5.9 ps pulses at 1030 nm, with pulse energies up to 125 μJ and a focused spot diameter of 35 μm. Use of a beam steering scan head allows flexibility in designing complicated scanning patterns. In this study we have demonstrated that picosecond pulses are capable of removing scleral tissue without introducing any major thermal damage which offers a possible route for minimally invasive sclerostomy. In assessing this we have tested several different scanning patterns including single line ablation, square and circular cavity removal.

Radiofrequency Ablation for the Treatment of Hepatocellular Carcinoma in Patients with Transjugular Intrahepatic Portosystemic Shunts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Jonathan K., E-mail: jonathan.park09@gmail.com; Al-Tariq, Quazi Z., E-mail: qat200@gmail.com; Zaw, Taryar M., E-mail: taryar.zaw@gmail.com

PurposeTo assess radiofrequency (RF) ablation efficacy, as well as the patency of transjugular intrahepatic portosystemic shunts (TIPSs), in patients with hepatocellular carcinoma (HCC).Materials and MethodsRetrospective database review of patients with pre-existing TIPS undergoing RF ablation of HCC was conducted over a 159-month period ending in November 2013. TIPS patency pre- and post-RF ablation was assessed by ultrasound, angiography, and/or contrast-enhanced CT or MRI. Patient demographics and immediate post-RF ablation outcomes and complications were also reviewed.Results19 patients with 21 lesions undergoing 25 RF ablation sessions were included. Child-Pugh class A, B, and C scores were seen in 1, 13, and 5more » patients, respectively. Eleven patients (58 %) ultimately underwent liver transplantation. Immediate technical success was seen in all ablation sessions without residual tumor enhancement (100 %). No patients (0 %) suffered liver failure within 1 month of ablation. Pre-ablation TIPS patency was demonstrated in 22/25 sessions (88 %). Of 22 cases with patent TIPS prior to ablation, post-ablation patency was demonstrated in 22/22 (100 %) at immediate post-ablation imaging and in 21/22 (95 %) at last follow-up (1 patient was incidentally noted to have occlusion 31 months later). No immediate complications were observed.ConclusionAblation efficacy was similar to the cited literature values for patients without TIPS. Furthermore, TIPS patency was preserved in the majority of cases. Patients with both portal hypertension and HCC are not uncommonly encountered, and a pre-existing TIPS does not appear to be a definite contraindication for RF ablation.« less

Acute and long term outcomes of catheter ablation using remote magnetic navigation for the treatment of electrical storm in patients with severe ischemic heart failure.

PubMed

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

2015-03-15

Catheter ablation with remote magnetic navigation (RMN) can offer some advantages compared to manual techniques. However, the relevant clinical evidence for how RMN-guided ablation affects electrical storm (ES) due to ventricular tachycardia (VT) in patients with severe ischemic heart failure (SIHF) is still limited. Forty consecutive SIHF patients (left ventricular ejection fraction, 21 ± 6.9%) presenting with ES underwent ablation using RMN. All the patients received implantable cardioverter-defibrillators (ICDs) either before or after ablation. Acute ablation success was defined as noninducibility of any sustained monophasic VT at the end of the procedure. Long-term analysis addressed VT recurrence, ICD therapies and all-cause death. ES was acutely suppressed by ablation in all patients. Acute ablation success was obtained in 32 of 40 (80%) patients. The procedure time and fluoroscopy time were 105 ± 27 min and 7.5 ± 4.8 min respectively. No major complications occurred during procedures. During a mean follow-up of 17.4 months, 19 patients (47.5%) remained free of VT recurrence. The percentage of patients receiving ICD shocks after ablation was lower than before ablation (30% vs 69%, P<0.01). The mean number of ICD shocks per individual per year was reduced from 4.3 before ablation to 1.9 after ablation (P<0.05). Ten patients died during follow-up. Acute catheter ablation with RMN is safe and effective to suppress ES in SIHF patients. RMN-guided catheter ablation can prevent VT recurrence and significantly reduce ICD shocks, suggesting that this strategy can be used as an alternative therapy for VT storm in SIHF patients with ICDs. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Laser ablation molecular isotopic spectroscopy (LAMIS) towards the determination of multivariate LODs via PLS calibration model of 10B and 11B Boric acid mixtures

NASA Astrophysics Data System (ADS)

Harris, C. D.; Profeta, Luisa T. M.; Akpovo, Codjo A.; Johnson, Lewis; Stowe, Ashley C.

2017-05-01

A calibration model was created to illustrate the detection capabilities of laser ablation molecular isotopic spectroscopy (LAMIS) discrimination in isotopic analysis. The sample set contained boric acid pellets that varied in isotopic concentrations of 10B and 11B. Each sample set was interrogated with a Q-switched Nd:YAG ablation laser operating at 532 nm. A minimum of four band heads of the β system B2∑ -> Χ2∑transitions were identified and verified with previous literature on BO molecular emission lines. Isotopic shifts were observed in the spectra for each transition and used as the predictors in the calibration model. The spectra along with their respective 10/11B isotopic ratios were analyzed using Partial Least Squares Regression (PLSR). An IUPAC novel approach for determining a multivariate Limit of Detection (LOD) interval was used to predict the detection of the desired isotopic ratios. The predicted multivariate LOD is dependent on the variation of the instrumental signal and other composites in the calibration model space.

Optical aberrations induced by subclinical decentrations of the ablation pattern

NASA Astrophysics Data System (ADS)

Mrochen, Michael; Kaemmerer, Maik; Riedel, Peter; Mierdel, Peter; Krinke, Hans-Eberhard; Seiler, Theo

2000-06-01

Purpose: The aim of this work was to study the effect of currently used ablation profiles along with eccentric ablations on the increase of higher order aberrations observed after PRK. Material and Methods: The optical aberrations of 10 eyes were tested before and after PRK. Refractive surgery was performed using a ArF-excimer laser system. In all cases, the ablation zone was 6 mm or larger. The spherical equivalent of the correction was ranging from -2.5 D to -6.0 D. The measured wavefront error was compared to numerical simulations done with the reduced eye model and currently used ablation profiles as well as compared with experimental results obtained from ablation on PMMA balls. Results: The aberration measurements result in a considerable change of the spherical- and coma-like wavefront errors. This result was in good correlation with the numerical simulations and the experimental results. Furthermore, it has been derived that the major contribution on the induced higher order aberrations are a result of the small decentration (less than 1.0 mm) of the ablation zone. Conclusions: Higher order spherical- and coma-like aberrations after PRK are mainly determined by the decentration of the ablation zone during laser refractive surgery. However, future laser systems should use efficient eye-tracking systems and aspherical ablation profiles to overcome this problem.

Real-time tracking and virtual endoscopy in cone-beam CT-guided surgery of the sinuses and skull base in a cadaver model.

PubMed

Prisman, Eitan; Daly, Michael J; Chan, Harley; Siewerdsen, Jeffrey H; Vescan, Allan; Irish, Jonathan C

2011-01-01

Custom software was developed to integrate intraoperative cone-beam computed tomography (CBCT) images with endoscopic video for surgical navigation and guidance. A cadaveric head was used to assess the accuracy and potential clinical utility of the following functionality: (1) real-time tracking of the endoscope in intraoperative 3-dimensional (3D) CBCT; (2) projecting an orthogonal reconstructed CBCT image, at or beyond the endoscope, which is parallel to the tip of the endoscope corresponding to the surgical plane; (3) virtual reality fusion of endoscopic video and 3D CBCT surface rendering; and (4) overlay of preoperatively defined contours of anatomical structures of interest. Anatomical landmarks were contoured in CBCT of a cadaveric head. An experienced endoscopic surgeon was oriented to the software and asked to rate the utility of the navigation software in carrying out predefined surgical tasks. Utility was evaluated using a rating scale for: (1) safely completing the task; and (2) potential for surgical training. Surgical tasks included: (1) uncinectomy; (2) ethmoidectomy; (3) sphenoidectomy/pituitary resection; and (4) clival resection. CBCT images were updated following each ablative task. As a teaching tool, the software was evaluated as "very useful" for all surgical tasks. Regarding safety and task completion, the software was evaluated as "no advantage" for task (1), "minimal" for task (2), and "very useful" for tasks (3) and (4). Landmark identification for structures behind bone was "very useful" for both categories. The software increased surgical confidence in safely completing challenging ablative tasks by presenting real-time image guidance for highly complex ablative procedures. In addition, such technology offers a valuable teaching aid to surgeons in training. Copyright © 2011 American Rhinologic Society-American Academy of Otolaryngic Allergy, LLC.

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

PubMed

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

2013-01-01

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

Characteristics of Cavotricuspid Isthmus Ablation for Atrial Flutter Guided by Novel Parameters Using a Contact Force Catheter.

PubMed

Gould, Paul A; Booth, Cameron; Dauber, Kieran; Ng, Kevin; Claughton, Andrew; Kaye, Gerald C

2016-12-01

This study sought to investigate specific contact force (CF) parameters to guide cavotricuspid isthmus (CTI) ablation and compare the outcome with a historical control cohort. Patients (30) undergoing CTI ablation were enrolled prospectively in the Study cohort and compared with a retrospective Control cohort of 30 patients. Ablation in the Study cohort was performed using CF parameters >10 g and <40 g and a Force Time Integral (FTI) of 800 ± 10 g. The Control cohort underwent traditionally guided CTI ablation. Traditional parameters (electrogram and impedance change) were assessed in both cohorts. All ablations regardless of achieving targets were included in data analysis. Bidirectional CTI block was achieved in all of the Study and 27 of the Control cohort. Atrial flutter recurred in 3 (10%) patients (follow-up 564 ± 212 days) in the study cohort and in 3 (10%) patients (follow-up 804 ± 540 days) in the Control cohort. There were no major complications in either cohort. Traditional parameters correlated poorly with CF parameters. In the Study cohort, flutter recurrence was associated with significantly lower FTI and ablation duration, but was not associated with total average CF. CTI ablation can be safely performed using CF parameters guiding ablation, with similar long-term results to a historical ablation control group. Potentially CF parameters may provide adjunctive information to enable a more efficient CTI ablation. Further research is required to confirm this. © 2016 Wiley Periodicals, Inc.

Ultra-short pulse laser micro patterning with highest throughput by utilization of a novel multi-beam processing head

NASA Astrophysics Data System (ADS)

Homburg, Oliver; Jarczynski, Manfred; Mitra, Thomas; Brüning, Stephan

2017-02-01

In the last decade much improvement has been achieved for ultra-short pulse lasers with high repetition rates. This laser technology has vastly matured so that it entered a manifold of industrial applications recently compared to mainly scientific use in the past. Compared to ns-pulse ablation ultra-short pulses in the ps- or even fs regime lead to still colder ablation and further reduced heat-affected zones. This is crucial for micro patterning when structure sizes are getting smaller and requirements are getting stronger at the same time. An additional advantage of ultra-fast processing is its applicability to a large variety of materials, e.g. metals and several high bandgap materials like glass and ceramics. One challenge for ultra-fast micro machining is throughput. The operational capacity of these processes can be maximized by increasing the scan rate or the number of beams - parallel processing. This contribution focuses on process parallelism of ultra-short pulsed lasers with high repetition rate and individually addressable acousto-optical beam modulation. The core of the multi-beam generation is a smooth diffractive beam splitter component with high uniform spots and negligible loss, and a prismatic array compressor to match beam size and pitch. The optical design and the practical realization of an 8 beam processing head in combination with a high average power single mode ultra-short pulsed laser source are presented as well as the currently on-going and promising laboratory research and micro machining results. Finally, an outlook of scaling the processing head to several tens of beams is given.

Sphenopalatine ganglion: block, radiofrequency ablation and neurostimulation - a systematic review.

PubMed

Ho, Kwo Wei David; Przkora, Rene; Kumar, Sanjeev

2017-12-28

Sphenopalatine ganglion is the largest collection of neurons in the calvarium outside of the brain. Over the past century, it has been a target for interventional treatment of head and facial pain due to its ease of access. Block, radiofrequency ablation, and neurostimulation have all been applied to treat a myriad of painful syndromes. Despite the routine use of these interventions, the literature supporting their use has not been systematically summarized. This systematic review aims to collect and summarize the level of evidence supporting the use of sphenopalatine ganglion block, radiofrequency ablation and neurostimulation. Medline, Google Scholar, and the Cochrane Central Register of Controlled Trials (CENTRAL) databases were reviewed for studies on sphenopalatine ganglion block, radiofrequency ablation and neurostimulation. Studies included in this review were compiled and analyzed for their treated medical conditions, study design, outcomes and procedural details. Studies were graded using Oxford Center for Evidence-Based Medicine for level of evidence. Based on the level of evidence, grades of recommendations are provided for each intervention and its associated medical conditions. Eighty-three publications were included in this review, of which 60 were studies on sphenopalatine ganglion block, 15 were on radiofrequency ablation, and 8 were on neurostimulation. Of all the studies, 23 have evidence level above case series. Of the 23 studies, 19 were on sphenopalatine ganglion block, 1 study on radiofrequency ablation, and 3 studies on neurostimulation. The rest of the available literature was case reports and case series. The strongest evidence lies in using sphenopalatine ganglion block, radiofrequency ablation and neurostimulation for cluster headache. Sphenopalatine ganglion block also has evidence in treating trigeminal neuralgia, migraines, reducing the needs of analgesics after endoscopic sinus surgery and reducing pain associated with nasal packing removal after nasal operations. Overall, sphenopalatine ganglion is a promising target for treating cluster headache using blocks, radiofrequency ablation and neurostimulation. Sphenopalatine ganglion block also has some evidence supporting its use in a few other conditions. However, most of the controlled studies were small and without replications. Further controlled studies are warranted to replicate and expand on these previous findings.

Epicardial Radiofrequency Ablation Failure During Ablation Procedures for Ventricular Arrhythmias: Reasons and Implications for Outcomes.

PubMed

Baldinger, Samuel H; Kumar, Saurabh; Barbhaiya, Chirag R; Mahida, Saagar; Epstein, Laurence M; Michaud, Gregory F; John, Roy; Tedrow, Usha B; Stevenson, William G

2015-12-01

Radiofrequency ablation (RFA) from the epicardial space for ventricular arrhythmias is limited or impossible in some cases. Reasons for epicardial ablation failure and the effect on outcome have not been systematically analyzed. We assessed reasons for epicardial RFA failure relative to the anatomic target area and the type of heart disease and assessed the effect of failed epicardial RFA on outcome after ablation procedures for ventricular arrhythmias in a large single-center cohort. Epicardial access was attempted during 309 ablation procedures in 277 patients and was achieved in 291 procedures (94%). Unlimited ablation in an identified target region could be performed in 181 cases (59%), limited ablation was possible in 22 cases (7%), and epicardial ablation was deemed not feasible in 88 cases (28%). Reasons for failed or limited ablation were unsuccessful epicardial access (6%), failure to identify an epicardial target (15%), proximity to a coronary artery (13%), proximity to the phrenic nerve (6%), and complications (<1%). Epicardial RFA was impeded in the majority of cases targeting the left ventricular summit region. Acute complications occurred in 9%. The risk for acute ablation failure was 8.3× higher (4.5-15.0; P<0.001) after no or limited epicardial RFA compared with unlimited RFA, and patients with unlimited epicardial RFA had better recurrence-free survival rates (P<0.001). Epicardial RFA for ventricular arrhythmias is often limited even when pericardial access is successful. Variability of success is dependent on the target area, and the presence of factors limiting ablation is associated with worse outcomes. © 2015 American Heart Association, Inc.

Neofunctionalization of embryonic head patterning genes facilitates the positioning of novel traits on the dorsal head of adult beetles.

PubMed

Zattara, Eduardo E; Busey, Hannah A; Linz, David M; Tomoyasu, Yoshinori; Moczek, Armin P

2016-07-13

The origin and integration of novel traits are fundamental processes during the developmental evolution of complex organisms. Yet how novel traits integrate into pre-existing contexts remains poorly understood. Beetle horns represent a spectacular evolutionary novelty integrated within the context of the adult dorsal head, a highly conserved trait complex present since the origin of insects. We investigated whether otd1/2 and six3, members of a highly conserved gene network that instructs the formation of the anterior end of most bilaterians, also play roles in patterning more recently evolved traits. Using ablation-based fate-mapping, comparative larval RNA interference (RNAi) and transcript sequencing, we found that otd1/2, but not six3, play a fundamental role in the post-embryonic formation of the adult dorsal head and head horns of Onthophagus beetles. By contrast, neither gene appears to pattern the adult head of Tribolium flour beetles even though all are expressed in the dorsal head epidermis of both Onthophagus and Tribolium We propose that, at least in beetles, the roles of otd genes during post-embryonic development are decoupled from their embryonic functions, and that potentially non-functional post-embryonic expression in the dorsal head facilitated their co-option into a novel horn-patterning network during Onthophagus evolution. © 2016 The Author(s).

Neofunctionalization of embryonic head patterning genes facilitates the positioning of novel traits on the dorsal head of adult beetles

PubMed Central

Busey, Hannah A.; Linz, David M.; Tomoyasu, Yoshinori; Moczek, Armin P.

2016-01-01

The origin and integration of novel traits are fundamental processes during the developmental evolution of complex organisms. Yet how novel traits integrate into pre-existing contexts remains poorly understood. Beetle horns represent a spectacular evolutionary novelty integrated within the context of the adult dorsal head, a highly conserved trait complex present since the origin of insects. We investigated whether otd1/2 and six3, members of a highly conserved gene network that instructs the formation of the anterior end of most bilaterians, also play roles in patterning more recently evolved traits. Using ablation-based fate-mapping, comparative larval RNA interference (RNAi) and transcript sequencing, we found that otd1/2, but not six3, play a fundamental role in the post-embryonic formation of the adult dorsal head and head horns of Onthophagus beetles. By contrast, neither gene appears to pattern the adult head of Tribolium flour beetles even though all are expressed in the dorsal head epidermis of both Onthophagus and Tribolium. We propose that, at least in beetles, the roles of otd genes during post-embryonic development are decoupled from their embryonic functions, and that potentially non-functional post-embryonic expression in the dorsal head facilitated their co-option into a novel horn-patterning network during Onthophagus evolution. PMID:27412276

Brain Emboli After Left Ventricular Endocardial Ablation.

PubMed

Whitman, Isaac R; Gladstone, Rachel A; Badhwar, Nitish; Hsia, Henry H; Lee, Byron K; Josephson, S Andrew; Meisel, Karl M; Dillon, William P; Hess, Christopher P; Gerstenfeld, Edward P; Marcus, Gregory M

2017-02-28

Catheter ablation for ventricular tachycardia and premature ventricular complexes (PVCs) is common. Catheter ablation of atrial fibrillation is associated with a risk of cerebral emboli attributed to cardioversions and numerous ablation lesions in the low-flow left atrium, but cerebral embolic risk in ventricular ablation has not been evaluated. We enrolled 18 consecutive patients meeting study criteria scheduled for ventricular tachycardia or PVC ablation over a 9-month period. Patients undergoing left ventricular (LV) ablation were compared with a control group of those undergoing right ventricular ablation only. Patients were excluded if they had implantable cardioverter defibrillators or permanent pacemakers. Radiofrequency energy was used for ablation in all cases and heparin was administered with goal-activated clotting times of 300 to 400 seconds for all LV procedures. Pre- and postprocedural brain MRI was performed on each patient within a week of the ablation procedure. Embolic infarcts were defined as new foci of reduced diffusion and high signal intensity on fluid-attenuated inversion recovery brain MRI within a vascular distribution. The mean age was 58 years, half of the patients were men, half had a history of hypertension, and the majority had no known vascular disease or heart failure. LV ablation was performed in 12 patients (ventricular tachycardia, n=2; PVC, n=10) and right ventricular ablation was performed exclusively in 6 patients (ventricular tachycardia, n=1; PVC, n=5). Seven patients (58%) undergoing LV ablation experienced a total of 16 cerebral emboli, in comparison with zero patients undergoing right ventricular ablation ( P =0.04). Seven of 11 patients (63%) undergoing a retrograde approach to the LV developed at least 1 new brain lesion. More than half of patients undergoing routine LV ablation procedures (predominately PVC ablations) experienced new brain emboli after the procedure. Future research is critical to understanding the long-term consequences of these lesions and to determining optimal strategies to avoid them. © 2017 American Heart Association, Inc.

Apixaban for periprocedural anticoagulation during catheter ablation of atrial fibrillation: a systematic review and meta-analysis of 1691 patients.

PubMed

Blandino, Alessandro; Bianchi, Francesca; Biondi-Zoccai, Giuseppe; Grossi, Stefano; Conte, Maria Rosa; Rametta, Francesco; Gaita, Fiorenzo

2016-09-01

Apixaban, a direct factor Xa inhibitor recently approved for thromboembolic prophylaxis in patients with nonvalvular atrial fibrillation (AF), is increasingly used in patients undergoing catheter ablation of AF. However, large randomized studies supporting its use in the ablation context are still lacking. We undertook the present meta-analysis to assess the impact of apixaban in terms of thromboembolic and bleeding events in patients undergoing AF ablation as compared to warfarin. MEDLINE/PubMed, Cochrane Library, and references reporting AF ablation and apixaban were screened and studies included if matching inclusion and exclusion criteria. One randomized and five nonrandomized studies were included in the analysis. Patients enrolled were 1691 patients (668 on apixaban and 1023 on warfarin). There was no heterogeneity in all the outcome comparisons. No deaths were reported. We did not observe any difference between apixaban and warfarin with respect to thromboembolic events (OR = 1.10, 95 % CI 0.24-5.16), major bleedings (OR = 1.56, 95 % CI 0.59-4.13), cardiac tamponade (OR 1.69, 95 % CI 0.52-5.54), minor bleedings (OR 0.96, 95 % CI 0.58-1.59), and the composite endpoint of death, thromboembolic events, and bleedings (OR 1.03, 95 % CI 0.65-1.64). The rates of death, thromboembolic events, major bleedings including cardiac tamponade, and minor bleedings in patients on apixaban undergoing AF ablation are very low and similar to that seen in patients treated with uninterrupted warfarin. Although primary driven by nonrandomized studies, these results support apixaban as periprocedural anticoagulation during AF ablation procedures.

Effect of anticoagulation on endothermal ablation of the great saphenous vein.

PubMed

Sharifi, Mohsen; Mehdipour, Mahshid; Bay, Curt; Emrani, Farnaz; Sharifi, Jalaladdin

2011-01-01

A growing number of patients who are on systemic anticoagulation with warfarin require endovenous thermal ablation for reflux disease in the great saphenous vein (GSV). Little is known about the effects of anticoagulation on periprocedural bleeding and long-term closure rates of the treated veins. This study evaluated the effects of uninterrupted anticoagulation in patients undergoing endovenous thermal ablation. In this prospective observational study, 88 limbs of patients on warfarin (anticoagulation group [AG]) who underwent endovenous thermal ablation for GSV reflux disease were compared with 92 limbs in patients receiving no anticoagulation or antiplatelet agents (control group [CG]). Forty percent of AG patients were also receiving antiplatelet therapy. Periprocedural bleeding and closure rate at 1 year were evaluated. No major bleeding occurred in either group. Minor bleeding was noted in 8 of 88 procedures in the AG vs 4 of 92 in the CG (P = 0.24); all in patients receiving radiofrequency ablation. Four of the eight minor bleeds in the AG were noted in patients receiving "triple therapy" with warfarin, aspirin, and clopidogrel or ticlopidine. Triple therapy in the AG was associated with a higher risk of minor bleeding compared with the CG (relative risk, 13.0; 95% confidence interval, 4.10-41.19, P < .001). All treated venous segments remained closed at the 1-year follow-up in both groups. In this relatively small, nonrandomized study comparing endovenous thermal ablation in patients with and without warfarin, no differences were found in periprocedural risk of major bleeding or closure rate of the treated venous segments. Minor bleeding was increased in patients receiving triple therapy with warfarin, aspirin, and a thienopyridine who underwent radiofrequency ablation. Copyright © 2011 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

Irreversible electroporation as treatment of locally advanced and as margin accentuation in borderline resectable pancreatic adenocarcinoma.

PubMed

Marsanic, P; Mellano, A; Sottile, A; De Simone, M

2017-07-01

In recent years, many local ablation technologies based on thermal damage have been used in the treatment of locally advanced pancreatic carcinoma (LAPC) and borderline resectable pancreatic carcinoma (BLRPC). However, they are associated with major complications because of possible vascular and ductal damage. Irreversible electroporation (IRE) is a nonthermal ablation technology that seems safe near vital vascular and ductal structures. IRE could be used as exclusive treatment of LAPC (en situ to IRE) after induction chemotherapy In BLRPC, surgery is not really radical in 6% of patients (microscopic residual) and local recurrences occur in 11-42% of apparent radical resections. IRE could be used as margin accentuation to increase posterior margin during radical surgery in BLRPC. Our outcomes are safety, time to progression. Secondary outcomes are overall survival, pain control and quality of life. We are performing a prospective evaluation of patients undergoing IRE for LAPC or BLRPC since July 2014. We have included patients with non-metastatic LAPC with maximum size ≤4 cm (en situ to IRE) and patients with BLRPC (complementary IRE). We have performed induction chemotherapy in both groups. After treatment, patients were evaluated on days 1, 2, 4, 7, 14, 21, 30, 60 and 90 with amylase and lipase serum and abdominal drainage test. Based on Ethics Committee's request, follow-up imaging was performed at the 10th day for safety evaluation, at 30, 60 and 90 days for response evaluation and then every 3 months. Seven patients (two women and five men) underwent IRE. Two patients had LAPC and received en situ to IRE. In five patients affected by BLRPC we performed IRE and pancreatic head resection. In all patients, intraoperative imaging confirmed that the treatment of the whole tumor volume was complete. All seven patients demonstrated nonclinically relevant elevation of their amylase and lipase, which returned normal at 5 days postprocedure. No patient showed evidence of clinical pancreatitis or fistula. No major complications were recorded. Patients with LAPC died of distant metastases 6 month after treatment. At 3- and 6-month follow-up, all patients with BLPRC were alive and disease free. Only one patient has already reached 9-month follow-up and is alive and disease free. Our results are only preliminary. However, IRE ablation of LAPC and BLRPC seems a safe and feasible treatment.

Catheter ablation of atrial fibrillation in patients with concomitant sinus bradycardia-Insights from the German Ablation Registry.

PubMed

Zylla, Maura M; Brachmann, Johannes; Lewalter, Thorsten; Hoffmann, Ellen; Kuck, Karl-Heinz; Andresen, Dietrich; Willems, Stephan; Hochadel, Matthias; Senges, Jochen; Katus, Hugo A; Thomas, Dierk

2016-01-01

This investigation addresses procedural characteristics of catheter ablation in patients with atrial fibrillation (AF) and sinus bradycardia. From the prospective, multi-center German Ablation Registry 1073 patients with sinus rhythm at the time of AF ablation were divided into two groups according to heart rate at start of procedure (A, <60 beats per minute (bpm), n=197; B, 60-99bpm, n=876). Acute procedural success was high (≥98%) and similar between groups. Procedure duration and energy application time were increased in group A (180min vs. 155min and 2561s vs. 1879s, respectively). Major complications were more frequent in group A (2.2% vs. 0.5%), and a greater proportion of these patients was discharged under antiarrhythmic medication (64% vs. 52%). Catheter ablation of AF with concomitant sinus bradycardia is associated with high procedural efficacy, longer procedure- and energy application durations, and a slightly elevated complication rate. Copyright © 2016 Elsevier Inc. All rights reserved.

Therapy of Pancreatic Neuroendocrine Tumors: Fine Needle Intervention including Ethanol and Radiofrequency Ablation

PubMed Central

Lakhtakia, Sundeep

2017-01-01

Pancreatic neuroendocrine tumors (PNETs) are increasingly being detected, though usually as incidental findings. Majority of the PNETs are non-functional and surgical resection is the standard of care for most of them. However, in patients with small PNETs localized within the pancreas, who are unfit or unwilling for surgery, alternate methods of treatment are needed. Direct methods of ablation of PNETs, using either ethanol injection or radiofrequency ablation (RFA), are emerging as effective methods. The limited literature available as case reports or case series on endoscopic ultrasound (EUS)-guided local ablation using either ethanol or RFA has demonstrated safety and efficacy along with short- to medium-term sustained relief. Long-term benefits with these local ablative therapies are awaited. Comparative studies are needed to show which of these two competing technologies is superior. Finally, comparative trials of EUS-guided ablation with surgical resection in terms of efficacy and safety will ensure their place in the management algorithm. PMID:29207860

Ablation in teeth with the free-electron laser around the absorption peak of hydroxyapatite (9.5 μm) and between 6.0 and 7.5 μm

NASA Astrophysics Data System (ADS)

Ostertag, Manfred; Walker, Rudolf; Weber, Heiner; van der Meer, Lex; McKinley, Jim T.; Tolk, Norman H.; Jean, Benedikt J.

1996-04-01

Pulsed IR laser ablation on dental hard substances was studied in the wavelength range between 9.5 and 11.5 micrometers with the Free-Electron Laser (FEL) in Nieuwegein/NL and between 6.0 and 7.5 micrometers with the FEL at Vanderbilt University in Nashville/TN. Depth, diameter and volume of the ablation crater were determined with a special silicon replica method and subsequent confocal laser topometry. The irradiated surfaces and the ejected debris were examined with an SEM 9.5 - 11.5 micrometers : depth, diameter and volume of the ablation crater are greater and the ablation threshold is lower for ablation with a wavelength corresponding to the absorption max. of hydroxyapatite (9.5 micrometers ), compared to ablation at wavelengths with lower absorption (10.5 - 11.5 micrometers ). For all wavelengths, no thermal cracking can be observed after ablation in dentine, however a small amount of thermal cracking can be observed after ablation in enamel. After ablation at 9.5 micrometers , a few droplets of solidified melt were seen on the irradiated areas, whereas the debris consisted only of solidified melt. In contrast, the surface and the debris obtained from ablation using the other wavelengths showed the natural structure of dentine 6.0 - 7.5 micrometers : the depth of the ablation crater increases and the ablation threshold decreases for an increasing absorption coefficient of the target material. Different tissue components absorbed the laser radiation of different wavelengths (around 6.0 micrometers water and collagen, 6.5 micrometers collagen and water, 7.0 micrometers carbonated hydroxyapatite). Nevertheless the results have shown no major influence on the primary tissue absorber.

Targeted multifunctional gold-based nanoshells for magnetic resonance-guided laser ablation of head and neck cancer.

PubMed

Melancon, Marites P; Lu, Wei; Zhong, Meng; Zhou, Min; Liang, Gan; Elliott, Andrew M; Hazle, John D; Myers, Jeffrey N; Li, Chun; Stafford, R Jason

2011-10-01

Image-guided thermal ablation of tumors is becoming a more widely accepted minimally invasive alternative to surgery for patients who are not good surgical candidates, such as patients with advanced head and neck cancer. In this study, multifunctional superparamagnetic iron oxide coated with gold nanoshell (SPIO@Au NS) that have both optical and magnetic properties was conjugated with the targeting agent, C225 monoclonal antibody, against epidermal growth factor receptor (EGFR). C225-SPIO@Au NS have an average a diameter of 82 ± 4.4 nm, contain 142 ± 15 antibodies per nanoshell, have an absorption peak in the near infrared (~800 nm), and have transverse relaxivity (r(2)) of 193 and 353 mM(-1) s(-1) versus Feridex™ of 171 and 300 mM(-1) s(-1), using 1.5 T and 7 T MR scanners, respectively. Specific targeting of the synthesized C225-SPIO@Au NS was tested in vitro using A431 cells and oral cancer cells, FaDu, OSC19, and HN5, all of which overexpress EGFR. Selective binding was achieved using C225-SPIO@Au NS but not with the non-targeting PEG-SPIO@Au NS and blocking group (excess of C225 + C225-SPIO@Au NS). In vivo biodistribution on mice bearing A431 tumors also showed selective targeting of C225-SPIO@Au NS compared with the non-targeting and blocking groups. The selective photothermal ablation of the nanoshells shows that without laser treatment there were no cell death and among the groups that were treated with laser at a power of 36 W/cm(2) for 3 min, only the cells treated with C225-SPIO@Au NS had cell killing (p < 0.001). In summary, successful synthesis and characterization of targeted C225-SPIO@Au NS demonstrating both superparamagnetic and optical properties has been achieved. We have shown both in vitro and in vivo that these nanoshells are MR-active and can be selectively heated up for simultaneous imaging and photothermal ablation therapy. Published by Elsevier Ltd.

Reasons for recurrent ventricular tachycardia after catheter ablation of post-infarction ventricular tachycardia.

PubMed

Yokokawa, Miki; Desjardins, Benoit; Crawford, Thomas; Good, Eric; Morady, Fred; Bogun, Frank

2013-01-08

The purpose of this study was to assess the determinants of ventricular tachycardia (VT) recurrence in patients who underwent VT ablation for post-infarction VT. The factors that predict recurrence of VT after catheter ablation in patients with prior infarctions are not well described. Catheter ablation was performed in 98 consecutive patients (88 males [90%]; mean age 67 ± 10 years; ejection fraction 27 ± 13%) with post-infarction VT. Electrograms from the implantable cardioverter-defibrillator were analyzed, and VTs were classified as clinical, nonclinical, or new clinical. A total of 725 VTs were induced during the ablation procedure. All VTs were targeted. In 76 patients, 105 clinical VTs were inducible. Critical sites were identified with entrainment mapping and pace-mapping (≥10 of 12 matching leads) for 75 of 105 clinical VTs (71%) and for 278 of 620 nonclinical VTs (45%). Post-ablation, the clinical VT was not inducible in any patient, and all VTs were rendered noninducible in 63% of the patients. Over a mean follow-up period of 35 ± 23 months, 65 of 98 patients (66%) had no recurrent VTs and 33 (34%) had VT recurrence. A new VT occurred in 26 of 33 patients (79%), and a prior clinical VT recurred in 7 patients (21%). Patients with recurrent VT had a larger scar area as assessed by electroanatomic mapping compared with patients without recurrent VTs (93 ± 40 cm(2) vs. 69 ± 30 cm(2); p = 0.002). In patients with repeat procedures, the majority of inducible VTs for which a critical area could be identified were at a distance of 6 ± 3 mm to the prior ablation lesions. Patients with recurrent VTs have a larger scar as assessed by electroanatomic mapping. Most recurrent VTs were new, and the majority of these VTs were mapped to the vicinity of prior ablation lesions in patients with repeat procedures. Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Endourethral MRI Guidance for Prostatic RF Ablation

DTIC Science & Technology

2005-06-01

head (3 cm wide) attached to a 24-cm plastic handle,. Copper tape and then covered with a coat of protective plastic. In addition, bazooka baluns made...in the perineum , advanced posterior surface. This arrangement was used to mimic the into the prostatic urethra, and fixated in the prostate by...are inserted through the perineum placed in the left lateral decubitus position to maximize and into the prostate gland, commonly under ultrasound

Reconstructive Trends in Post-Ablation Patients with Esophagus and Hypopharynx Defect

PubMed Central

Choi, Jong Hwan; Sim, Seung Hyun

2015-01-01

The main challenge in pharyngoesophageal reconstruction is the restoration of swallow and speech functions. The aim of this paper is to review the reconstructive options and associated complications for patients with head and neck cancer. A literature review was performed for pharynoesophagus reconstruction after ablative surgery of head and neck cancer for studies published between January 1980 to July 2015 and listed in the PubMed database. Search queries were made using a combination of 'esophagus' and 'free flap', 'microsurgical', or 'free tissue transfer'. The search query resulted in 123 studies, of which 33 studies were full text publications that met inclusion criteria. Further review into the reference of these 33 studies resulted in 15 additional studies to be included. The pharyngoesophagus reconstruction should be individualized for each patient and clinical context. Fasciocutaneous free flap and pedicled flap are effective for partial phayngoesophageal defect. Fasciocutaneous free flap and jejunal free flap are effective for circumferential defect. Pedicled flaps remain a safe option in the context of high surgical risk patients, presence of fistula. Among free flaps, anterolateral thigh free flap and jejunal free flap were associated with superior outcomes, when compared with radial forearm free flap. Speech function is reported to be better for the fasciocutaneous free flap than for the jejunal free flap. PMID:28913234

Holmium: yttrium aluminum garnet laser-assisted endoscopic sinus surgery: laboratory experience.

PubMed

Shapshay, S M; Rebeiz, E E; Bohigian, R K; Hybels, R L; Aretz, H T; Pankratov, M M

1991-02-01

Endoscopic sinus surgery has gained wide acceptance since its introduction into the United States. Complex sinus anatomy and troublesome bleeding have been associated with complications, which vary in severity from synechia to blindness and leakage of cerebrospinal fluid. Endoscopic sinus surgery using a holmium: yttrium aluminum garnet pulsed solid-state laser oscillating at 2.1 microns with fiberoptic delivery was performed in the laboratory, and the results were compared with those of conventional endoscopic sinus surgery. Three beagle dogs, six human cadaver heads, and one calf head were used in the in vivo and in vitro studies to evaluate the bone ablation, tissue coagulation, and hemostatic properties of the holmium: yttrium aluminum garnet laser. Modified endoscopic telescopes for sinus surgery, a newly developed handpiece for fiberoptic delivery, and other surgical instruments were used. The results indicate that the holmium: yttrium aluminum garnet laser and new delivery instrumentation provide good hemostasis and controlled soft-tissue ablation and bone removal. The access to all sinuses in the human cadaver model was very good. The canine in vivo study showed delayed but complete healing on the laser-treated side. Clinical evaluation of the holmium: yttrium aluminum garnet laser is warranted to increase the precision and safety of endoscopic sinus surgery.

Percutaneous thrombin injection treatment of a gluteal pseudoaneurysm following radiofrequency ablation of a hip osteoid osteoma in a 6-year-old boy.

PubMed

Kumar, Abhishek; Ramchand, Tekchand; Contractor, Sohail

2014-12-01

Osteoid osteomas are benign bone lesions that present with bone pain in children and young adults. Over the last 2 decades, radiofrequency ablation has become the mainstay of treatment and is now preferred over surgical resection. Major complications of the procedure are very rare, consisting mostly of local skin burns. We present a case of a child presenting with a gluteal pseudoaneursym following CT-guided radiofrequency ablation of an acetabular osteoid osteoma, which was then treated successfully with percutaneous thrombin injection.

Mechanochemical endovenous ablation of saphenous veins using the ClariVein: A systematic review.

PubMed

Witte, Marianne E; Zeebregts, Clark J; de Borst, Gert Jan; Reijnen, Michel M P J; Boersma, Doeke

2017-12-01

Objective To systematically review all available English literature on mechanochemical endovenous ablation and to report on the anatomical, technical, and clinical success. Methods A systematic literature search was performed in PubMed, EMBASE, and the Cochrane Library on mechanochemical endovenous ablation for the treatment of insufficient great and/or small saphenous vein. Methodological quality of the included studies was evaluated using the MINORS score. The primary outcome measure was anatomical success, defined as closure of the treated vein on follow-up duplex ultrasound imaging. Secondary outcomes were technical and clinical success, and major complications defined as deep venous thrombosis, pulmonary embolisms or paresthesia. Results The literature search identified 759 records, of which 13 were included, describing 10 unique cohorts. A total of 1521 veins (1267 great saphenous vein and 254 small saphenous vein) were included, with cohort sizes ranging from 30 to 570 veins. The pooled anatomical success rate after short-term follow up was 92% (95% CI 90-94%) ( n = 1314 veins). After 6 and 12 months these numbers were 92% (95% CI 88-95%) ( n = 284) and 91% (95% CI 86-94%) ( n = 228), respectively. The long-term anatomical success rates at 2 and 3 years were 91% (95% CI 85-95%) ( n = 136) and 87% (95% CI 75-94%) ( n = 48), respectively. Major complications and especially nerve injury were very rare (≤ 0.2%). All studies were of moderate or good quality using the MINORS scoring scale. Conclusions Mechanochemical endovenous ablation using the ClariVein in combination with liquid sclerosant is associated with an anatomical success rate ranging from 87% to 92% and good clinical success. To date, no randomized controlled trials are available studying the anatomical success after mechanochemical ablation, compared to the endothermal ablation. The risk of major complications is very low after the procedure.

The magnetic navigation system allows safety and high efficacy for ablation of arrhythmias

PubMed Central

Bauernfeind, Tamas; Akca, Ferdi; Schwagten, Bruno; de Groot, Natasja; Van Belle, Yves; Valk, Suzanne; Ujvari, Barbara; Jordaens, Luc; Szili-Torok, Tamas

2011-01-01

Aims We aimed to evaluate the safety and long-term efficacy of the magnetic navigation system (MNS) in a large number of patients. The MNS has the potential for improving safety and efficacy based on atraumatic catheter design and superior navigation capabilities. Methods and results In this study, 610 consecutive patients underwent ablation. Patients were divided into two age- and sex-matched groups. Ablations were performed either using MNS (group MNS, 292) or conventional manual ablation [group manual navigation (MAN), 318]. The following parameters were analysed: acute success rate, fluoroscopy time, procedure time, complications [major: pericardial tamponade, permanent atrioventricular (AV) block, major bleeding, and death; minor: minor bleeding and temporary AV block]. Recurrence rate was assessed during follow-up (15 ± 9.5 months). Subgroup analysis was performed for the following groups: atrial fibrillation, isthmus dependent and atypical atrial flutter, atrial tachycardia, AV nodal re-entrant tachycardia, circus movement tachycardia, and ventricular tachycardia (VT). Magnetic navigation system was associated with less major complications (0.34 vs. 3.2%, P = 0.01). The total numbers of complications were lower in group MNS (4.5 vs. 10%, P = 0.005). Magnetic navigation system was equally effective as MAN in acute success rate for overall groups (92 vs. 94%, P = ns). Magnetic navigation system was more successful for VTs (93 vs. 72%, P < 0.05). Less fluoroscopy was used in group MNS (30 ± 20 vs. 35 ± 25 min, P < 0.01). There were no differences in procedure times and recurrence rates for the overall groups (168 ± 67 vs. 159 ± 75 min, P = ns; 14 vs. 11%, P = ns; respectively). Conclusions Our data suggest that the use of MNS improves safety without compromising efficiency of ablations. Magnetic navigation system is more effective than manual ablation for VTs. PMID:21508006

Left Atrial Anatomy Relevant to Catheter Ablation

PubMed Central

Sánchez-Quintana, Damián; Cabrera, José Angel; Saremi, Farhood

2014-01-01

The rapid development of interventional procedures for the treatment of arrhythmias in humans, especially the use of catheter ablation techniques, has renewed interest in cardiac anatomy. Although the substrates of atrial fibrillation (AF), its initiation and maintenance, remain to be fully elucidated, catheter ablation in the left atrium (LA) has become a common therapeutic option for patients with this arrhythmia. Using ablation catheters, various isolation lines and focal targets are created, the majority of which are based on gross anatomical, electroanatomical, and myoarchitectual patterns of the left atrial wall. Our aim was therefore to review the gross morphological and architectural features of the LA and their relations to extracardiac structures. The latter have also become relevant because extracardiac complications of AF ablation can occur, due to injuries to the phrenic and vagal plexus nerves, adjacent coronary arteries, or the esophageal wall causing devastating consequences. PMID:25057427

Liver Resection versus Radiofrequency Ablation plus Transcatheter Arterial Chemoembolization in Cirrhotic Patients with Solitary Large Hepatocellular Carcinoma.

PubMed

Saviano, Antonio; Iezzi, Roberto; Giuliante, Felice; Salvatore, Lucia; Mele, Caterina; Posa, Alessandro; Ardito, Francesco; De Gaetano, Anna Maria; Pompili, Maurizio

2017-11-01

To compare liver resection (LR) with single-step, balloon-occluded radiofrequency (RF) ablation plus drug-eluting embolics transarterial chemoembolization in cirrhotic patients with single hepatocellular carcinoma (HCC) ≥ 3 cm. From 2010 to 2014, 25 patients with compensated cirrhosis and single HCC ≥ 3 cm (median size 4.5 cm; range, 3.0-6.8 cm) not suitable for LR or liver transplantation were treated with RF ablation plus transarterial chemoembolization in a prospective observational single-center pilot study; all patients had complete tumor necrosis after treatment. A retrospective control group included 29 patients (median HCC size 4.0 cm; range, 3.0-7.4 cm) who underwent LR. RF ablation plus transarterial chemoembolization group included more patients with severe portal hypertension (65.5% vs 35.0%, P = .017). Primary endpoints were overall survival (OS) and tumor recurrence (TR) rates. One death and 1 major complication (4%) were observed in LR group. No major complications were reported in RF ablation plus transarterial chemoembolization group (P = .463). OS rates at 1 and 3 years were 91.8% and 79.3% in LR group and 89.4% and 48.2% in RF ablation plus transarterial chemoembolization group (P = 0.117). TR rates at 1 and 3 years were 29.5% and 45.0% in LR group and 42.4% and 76.0% in RF ablation plus transarterial chemoembolization group (P = .034). Local tumor progression (LTP) rates at 3 years were significantly lower in LR group (21.8% vs 58.1%, P = .005). Similar results were found in patients with HCC ≤ 5 cm (TR rates 35.4% vs 75.1%, P = .016; LTP 16.0% vs 55.7%, P = .013). LR achieved lower TR and LTP rates than RF ablation plus transarterial chemoembolization, but 3-years OS rates were not statistically different between the 2 groups. RF ablation plus transarterial chemoembolization is an effective treatment option in patients with compensated cirrhosis and solitary HCC ≥ 3 cm unsuitable for LR. Copyright © 2017 SIR. Published by Elsevier Inc. All rights reserved.

Current strategy for treatment of patients with Wolff-Parkinson-White syndrome and asymptomatic preexcitation in Europe: European Heart Rhythm Association survey.

PubMed

Svendsen, Jesper Hastrup; Dagres, Nikolaos; Dobreanu, Dan; Bongiorni, Maria Grazia; Marinskis, Germanas; Blomström-Lundqvist, Carina

2013-05-01

The aims of this survey was to provide insight into treatment activity, the strategy of treatment, and risk stratification of patients with asymptomatic and symptomatic ventricular pre-excitation across Europe. Fifty-eight centres, members of the European Heart Rhythm Association EP research network, covering 20 countries answered the survey questions. All centres were high-volume ablation centres. A younger person with asymptomatic Wolff-Parkinson-White (WPW) pattern has a higher likelihood of being risk-stratified or receiving ablation therapy compared with an older subject. Two-thirds of centres report that they have observed a decline in the number of patients ablated for an accessory pathway during the last 10 years. Pre-excited atrial fibrillation is rarely seen. Discontinuation of a scheduled WPW ablation due to close vicinity of the accessory pathway to the AV node happens very rarely. Patients with a first episode of pre-excited atrial fibrillation would immediately be referred for catheter ablation to be performed within weeks by 80.4% of the centres. A significant proportion of responders (50.9%) would use electrical cardioversion to restore sinus rhythm in a patient with pre-excited atrial fibrillation. With respect to the choice of antiarrhythmic medication for a patient with pre-excited AF, the majority (80.0%) would choose class 1C antiarrhytmic drugs while waiting for a catheter ablation. A patient seen in the emergency room with a second episode of orthodromic atrioventricular reentry tachycardia would be referred for immediate ablation by 79.2-90.6% of centres depending on the presence of pre-excitation. The volume of paediatric ablations performed on children younger than 12 years was low (46.4%: 0 patients per year; 46.4%: 1-9 patients per year). The majority of responding centres (61-69%) report that their country lack national guidelines dealing with clinical strategies related to WPW. There is a need for national guidelines dealing with clinical strategy in patients with WPW syndrome. Older individuals with asymptomatic WPW pattern have a higher risk of not receiving risk stratification or curative therapy with ablation compared with younger patients, despite the higher risk of developing atrial fibrillation.

Management of ventricular tachycardia in the ablation era: results of the European Heart Rhythm Association Survey.

PubMed

Tilz, Roland Richard; Lenarczyk, Radoslaw; Scherr, Daniel; Haugaa, Kristina Herman; Iliodromitis, Konstantinos; Pürerfellner, Helmut; Kiliszek, Marek; Dagres, Nikolaos

2018-01-01

Patients with sustained ventricular tachycardia (VT) are at risk of sudden death. Treatment options for VT include antiarrhythmic drug therapy, insertion of an implantable cardioverter-defibrillator, and catheter ablation. Evidence on indications for VT ablation, timing, ablation strategies, and periprocedural management is sparse. The aim of this European Heart Rhythm Association (EHRA) survey was to evaluate clinical practice regarding management of VT among the European countries. An electronic questionnaire was sent to members of the EHRA Electrophysiology Research Network. Responses were received from 88 centres in 12 countries. The results have shown that management of VTs is very heterogeneous across the participating centres. Indications, periprocedural management, and ablation strategies vary substantially. This EP Wire survey has revealed that catheter ablation is the first-line therapy for the treatment of recurrent monomorphic stable VT in patients without structural heart disease as well as in patients with ischaemic cardiomyopathy and impaired left ventricular ejection fraction in the majority of centres. Furthermore, in patients with ischaemic cardiomyopathy and the first episode of monomorphic VT, most centres (62.0%) performed catheter ablation. On the contrary, in patients with non-ischaemic cardiomyopathy, amiodarone (41.4%) and catheter ablation (37.1%) are used in a very similar proportion. Ablation strategies, endpoints, and post-ablation antithrombotic management vary substantially among European centres. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions, please email: journals.permissions@oup.com.

Idiopathic ventricular outflow tract arrhythmias from the great cardiac vein: challenges and risks of catheter ablation.

PubMed

Steven, D; Pott, C; Bittner, A; Sultan, A; Wasmer, K; Hoffmann, B A; Köbe, J; Drewitz, I; Milberg, P; Lueker, J; Mönnig, G; Servatius, H; Willems, S; Eckardt, L

2013-11-20

Catheter ablation for idiopathic ventricular arrhythmia is well established but epicardial origin, proximity to coronary arteries, and limited accessibility may complicate ablation from the venous system in particular from the great cardiac vein (GCV). Between April 2009 and October 2010 14 patients (56 ± 15 years; 9 male) out of a total group of 117 patients with idiopathic outflow tract tachycardias were included undergoing ablation for idiopathic VT or premature ventricular contractions (PVC) originating from GCV. All patients in whom the PVC arose from the GCV were subject to the study. In these patients angiography of the left coronary system was performed with the ablation catheter at the site of earliest activation. Successful ablation was performed in 6/14 (43%) and long-term success was achieved in 5/14 (36%) patients. In 4/14 patients (28.6%) ablation was not performed. In another 4 patients (26.7%), ablation did not abolish the PVC/VT. In the majority, the anatomical proximity to the left coronary system prohibited effective RF application. In 3 patients RF application resulted in a coronary spasm with complete regression as revealed in repeat coronary angiography. A relevant proportion idiopathic VT/PVC can safely be ablated from the GCV without significant permanent coronary artery stenosis after RF application. Our data furthermore demonstrate that damage to the coronary artery system is likely to be transient. © 2013.

Attitudes toward Catheter Ablation for Atrial Fibrillation: A Nationwide Survey among Danish Cardiologists.

PubMed

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

2015-10-01

Catheter ablation for atrial fibrillation (AF) is an important but expensive procedure that is the subject of some debate. Physicians' attitudes toward catheter ablation may influence promotion and patient acceptance. This is the first study to examine the attitudes of Danish cardiologists toward catheter ablation for AF, using a nationwide survey. We developed a purpose-designed questionnaire to evaluate attitudes toward catheter ablation for AF that was sent to all Danish cardiologists (n = 401; response n = 272 (67.8%)). There was no association between attitudes toward ablation and the experience or age of the cardiologist with respect to patients with recurrent AF episodes with a duration of <48 hours or >7 days and/or need for cardioversion. The majority (69%) expected a recurrence of AF after catheter ablation in more than 30% of the cases. For patients with persistent longstanding AF with a duration of >1 year, the attitude toward ablation for longstanding AF was more likely to be positive with increasing age (P < 0.01) and years of experience of the cardiologist (P = 0.002). Danish cardiologists generally have a positive attitude toward catheter ablation for AF, maintain up-to-date knowledge of the procedure, and are aware what information on ablation treatment should be given to patients with AF. The cardiologists had a positive attitude toward ablation for AF in patients with AF episodes <48 hours and patients with episodes >7 days, or those who needed medical/electrical conversion, but a more negative attitude toward treating longstanding AF patients. © 2015 Wiley Periodicals, Inc.

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

PubMed

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

2015-11-01

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. 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) ablation time, fluoroscopy time, radiation dose, and complications were assessed. Stepwise regression was used to predict which variable could best predict acute restoration from AF to SR by ablation. Compared to PsAF, procedure time and RF ablation time were significantly increased in patients with L-PsAF (P = 0.01 and P < 0.001, respectively). No major complications occurred during the procedures in either PsAF or L-PsAF patients. Fifty five of 313 patients converted directly to SR by ablation. Compared to L-PsAF, the rate of SR restoration was significantly higher in PsAF (21 vs 12%, P = 0.03). 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 < 0.001). Catheter ablation using RMN is a safe and effective method for PsAF and L-PsAF. LA volume could be a predictor of direct restoration of SR from sustaining AF by ablation using RMN.

On dynamic gas ablation from spherical galaxies

NASA Astrophysics Data System (ADS)

Nepveu, M.

1981-05-01

Two-dimensional, time dependent gas dynamic calculations are presented on the transonic motion of galaxies through a cluster medium. Lea and De Young's (1976) calculations are extended to include violent behavior in the center. On time scales of 10 to the 8th yr, galaxies in clusters can already lose a significant fraction of their gaseous content (up to 50% has been found in the calculations). This dynamic ablation occurs through rarefaction rather than shock heating. Explosions in spherical galaxies become effective as mechanisms for gas removal only if the galaxy moves with respect to its surroundings. Speculations are made on stripping of spiral galaxies (moving head-on in a cluster); the Gunn and Gott (1972) stripping formula is put to doubt. A method is suggested to obtain information on the state of motion of field galaxies.

A Multi-channel Semicircular Canal Neural Prosthesis Using Electrical Stimulation to Restore 3D Vestibular Sensation

PubMed Central

Della Santina, Charles C.; Migliaccio, Americo A.; Patel, Amit H.

2009-01-01

Bilateral loss of vestibular sensation can be disabling. Those afflicted suffer illusory visual field movement during head movements, chronic disequilibrium and postural instability due to failure of vestibulo-ocular and vestibulo-spinal reflexes. A neural prosthesis that emulates the normal transduction of head rotation by semicircular canals could significantly improve quality of life for these patients. Like the 3 semicircular canals in a normal ear, such a device should at least transduce 3 orthogonal (or linearly separable) components of head rotation into activity on corresponding ampullary branches of the vestibular nerve. We describe the design, circuit performance and in vivo application of a head-mounted, semi-implantable multi-channel vestibular prosthesis that encodes head movement in 3 dimensions as pulse-frequency-modulated electrical stimulation of 3 or more ampullary nerves. In chinchillas treated with intratympanic gentamicin to ablate vestibular sensation bilaterally, prosthetic stimuli elicited a partly compensatory angular vestibulo-ocular reflex in multiple planes. Minimizing misalignment between the axis of eye and head rotation, apparently caused by current spread beyond each electrode’s targeted nerve branch, emerged as a key challenge. Increasing stimulation selectivity via improvements in electrode design, surgical technique and stimulus protocol will likely be required to restore AVOR function over the full range of normal behavior. PMID:17554821

Multi-species impurity granule injection and mass deposition projections in NSTX-U discharges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lunsford, R.; Bortolon, A.; Roquemore, A. L.

Here, by employing a neutral gas shielding (NGS) model to characterize impurity granule injection, the ablation rates for three different species of granule: lithium, boron, and carbon, are determined. Utilizing the duration of ablation events recorded on experiments performed at DIII-D to calibrate the NGS model, we quantify the ablation rate with respect to the plasma density profile. The species-specific granule shielding constant is then used to model granule ablation within NSTX-U discharges. Simulations of 300, 500 and 700 micron diameter granules injected at 50 m s –1 are presented for NSTX-U L-mode type plasmas, as well as H-mode dischargesmore » with low natural ELM frequency. Additionally, ablation calculations of 500 micron granules of each species are presented at velocities ranging from 50–150 m s –1. In H-mode discharges these simulations show that the majority of the injected granule is ablated within or just past the edge steep gradient region. At this radial position, the perturbation to the background plasma generated by the ablating granule can lead to conditions advantageous for the rapid triggering of ELM crashes.« less

Multi-species impurity granule injection and mass deposition projections in NSTX-U discharges

DOE PAGES

Lunsford, R.; Bortolon, A.; Roquemore, A. L.; ...

2017-05-16

Here, by employing a neutral gas shielding (NGS) model to characterize impurity granule injection, the ablation rates for three different species of granule: lithium, boron, and carbon, are determined. Utilizing the duration of ablation events recorded on experiments performed at DIII-D to calibrate the NGS model, we quantify the ablation rate with respect to the plasma density profile. The species-specific granule shielding constant is then used to model granule ablation within NSTX-U discharges. Simulations of 300, 500 and 700 micron diameter granules injected at 50 m s –1 are presented for NSTX-U L-mode type plasmas, as well as H-mode dischargesmore » with low natural ELM frequency. Additionally, ablation calculations of 500 micron granules of each species are presented at velocities ranging from 50–150 m s –1. In H-mode discharges these simulations show that the majority of the injected granule is ablated within or just past the edge steep gradient region. At this radial position, the perturbation to the background plasma generated by the ablating granule can lead to conditions advantageous for the rapid triggering of ELM crashes.« less

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

PubMed

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

2018-04-26

Conducting gaps in lesion sets are a major reason for failure of ablation procedures. Voltage mapping and pace-capture have been proposed for intra-procedural identification of gaps. We aimed to compare gap size measured acutely and chronically post-ablation to macroscopic gap size in a porcine model. Intercaval linear ablation was performed in eight Göttingen minipigs with a deliberate gap of ∼5 mm left in the ablation line. Gap size was measured by interpolating ablation contact force values between ablation tags and thresholding at a low force cut-off of 5 g. Bipolar voltage mapping and pace-capture mapping along the length of the line were performed immediately, and at 2 months, post-ablation. Animals were euthanized and gap sizes were measured macroscopically. Voltage thresholds to define scar were determined by receiver operating characteristic analysis as <0.56 mV (acutely) and <0.62 mV (chronically). Taking the macroscopic gap size as gold standard, error in gap measurements were determined for voltage, pace-capture, and ablation contact force maps. All modalities overestimated chronic gap size, by 1.4 ± 2.0 mm (ablation contact force map), 5.1 ± 3.4 mm (pace-capture), and 9.5 ± 3.8 mm (voltage mapping). Error on ablation contact force map gap measurements were significantly less than for voltage mapping (P = 0.003, Tukey's multiple comparisons test). Chronically, voltage mapping and pace-capture mapping overestimated macroscopic gap size by 11.9 ± 3.7 and 9.8 ± 3.5 mm, respectively. Bipolar voltage and pace-capture mapping overestimate the size of chronic gap formation in linear ablation lesions. The most accurate estimation of chronic gap size was achieved by analysis of catheter-myocardium contact force during ablation.

Sensory and motor properties of the cerebellar uvula and modulus

NASA Technical Reports Server (NTRS)

Robinson, F. R.

1985-01-01

The uvula and nodulus (vermal lobules 9 and 10) of the vestibulocerebellum are implicated by behavioral evidence in the control of eye and head movements and in the production of motion sickness. The uvula and nodulus could play a role in these functions through known output pathways. Purkinje cells in both structures project via the fastigial and vestibular nuceli to the ventral horn of the cervical spin cord, to oculomotor neurons, and to the emetic region of the reticular formation (ablation of which abolishes susceptability to motion sickness). Uvula and nodulus Purkinje cells will be analyzed in cats trained to make controlled head movements. The activity of these neurons is expected to modulate well during head and/or eye movements because the uvula and nodulus receive heavy projections from sources of visual, vestibular and neck proprioceptive information. How neuron activity contributes to movement and how different sensory inputs converge to influence this contribution may be determined by characterizing movement related properties of these neurons. A population of neurons that modulates powerfully to the conflict between different head movement signals that can cause motion sickness may be identified.

Impact of pre-operative body mass index in head and neck cancer patients undergoing microvascular reconstruction.

PubMed

Hyun, D-J; Joo, Y-H; Kim, M-S

2017-11-01

To analyse the relationship of pre-operative body mass index with surgical complications and oncological outcomes in patients undergoing microvascular reconstruction for head and neck squamous cell cancer. A retrospective review was conducted of 259 patients who underwent microvascular free flap reconstruction after head and neck ablative surgery. Mean body mass index was 22.48 kg/m2. There were no correlations between body mass index and: flap failure (p = 0.739), flap ischaemia (p = 0.644), pharyngocutaneous fistula (p = 0.141) or wound infection (p = 0.224). The five-year disease-specific survival rate was 63 per cent. On univariate analysis, the five-year disease-specific survival rate was significantly correlated with pre-operative body mass index, based on Kaplan-Meier survival curves (p = 0.028). The five-year disease-specific survival rates in underweight, normal weight, overweight and obese groups were 47 per cent, 55 per cent, 65 per cent and 80 per cent, respectively. Pre-operative body mass index was a useful predictor for recurrence and survival in patients who underwent microvascular reconstruction for head and neck squamous cell cancer.

Development of Inspection and Repair Technology for Heat Exchanger Tubes in Fast Breeder Reactors

DTIC Science & Technology

2009-06-01

Technology for Heat Exchanger Tubes in Fast Breeder Reactors Akihiko NISHIMURA *1 , Takahisa SHOBU, Kiyoshi OKA, Toshihiko YAMAGUCHI, Yukihiro SHIMADA...fast breeder reactors (FBRs). It comprises a laser processing head combined with an eddy current testing unit. Ultrashort laser pulse ablation is used...be applied in the main- tenance of large structures such as nuclear reactors and chemical factories [1]. Internal access to a blanket cooling pipe

Atomic force microscopy analysis of human cornea surface after UV (λ=266 nm) laser irradiation

NASA Astrophysics Data System (ADS)

Spyratou, E.; Makropoulou, M.; Moutsouris, K.; Bacharis, C.; Serafetinides, A. A.

2009-07-01

Efficient cornea reshaping by laser irradiation for correcting refractive errors is still a major issue of interest and study. Although the excimer laser wavelength of 193 nm is generally recognized as successful in ablating corneal tissue for myopia correction, complications in excimer refractive surgery leads to alternative laser sources and methods for efficient cornea treatment. In this work, ablation experiments of human donor cornea flaps were conducted with the 4th harmonic of an Nd:YAG laser, with different laser pulses. AFM analysis was performed for examination of the ablated cornea flap morphology and surface roughness.

Synergistic growth inhibition of squamous cell carcinoma of the head and neck by erlotinib and epigallocatechin-3-gallate: the role of p53-dependent inhibition of nuclear factor-kappaB.

PubMed

Amin, A R M Ruhul; Khuri, Fadlo R; Chen, Zhuo Georgia; Shin, Dong M

2009-06-01

We have previously reported that the green tea polyphenol epigallocatechin-3-gallate (EGCG) and the epidermal growth factor receptor-tyrosine kinase inhibitor erlotinib had synergistic growth-inhibitory effects in cell culture and a nude mouse xenograft model of squamous cell carcinoma of the head and neck. However, the mechanism of their antitumor synergism is not fully understood. In the current study, we investigate the mechanism of their synergistic growth-inhibitory effects. The treatment of squamous cell carcinoma of the head and neck cell lines with erlotinib time-dependently increased the expression of cell cycle regulatory proteins p21 and p27 and apoptosis regulatory protein Bim. EGCG alone had very little or no effect on the expression of these proteins among the cell lines. However, simultaneous treatment with EGCG and erlotinib strongly inhibited erlotinib-induced expression of p21 and p27 without affecting the expression of Bim. Moreover, erlotinib increased the expression of p53 protein, the ablation of which by short hairpin RNA strongly inhibited EGCG- and erlotinib-mediated growth inhibition and the expression of p21, p27, and Bim. In addition, combined treatment with erlotinib and EGCG inhibited the protein level of p65 subunit of nuclear factor-kappaB and its transcriptional target Bcl-2, but failed to do so in cells with ablated p53. Taken together, our results, for the first time, suggest that erlotinib treatment activates p53, which plays a critical role in synergistic growth inhibition by erlotinib and EGCG via inhibiting nuclear factor-kappaB signaling pathway. Characterizing the underlying mechanisms of EGCG and erlotinib synergism will provide an important rationale for chemoprevention or treatment trials using this combination.

Laboratory Simulations of Micrometeoroid Ablation

NASA Astrophysics Data System (ADS)

Thomas, Evan Williamson

Each day, several tons of meteoric material enters Earth's atmosphere, the majority of which consist of small dust particles (micrometeoroids) that completely ablate at high altitudes. The dust input has been suggested to play a role in a variety of phenomena including: layers of metal atoms and ions, nucleation of noctilucent clouds, effects on stratospheric aerosols and ozone chemistry, and the fertilization of the ocean with bio-available iron. Furthermore, a correct understanding of the dust input to the Earth provides constraints on inner solar system dust models. Various methods are used to measure the dust input to the Earth including satellite detectors, radar, lidar, rocket-borne detectors, ice core and deep-sea sediment analysis. However, the best way to interpret each of these measurements is uncertain, which leads to large uncertainties in the total dust input. To better understand the ablation process, and thereby reduce uncertainties in micrometeoroid ablation measurements, a facility has been developed to simulate the ablation of micrometeoroids in laboratory conditions. An electrostatic dust accelerator is used to accelerate iron particles to relevant meteoric velocities (10-70 km/s). The particles are then introduced into a chamber pressurized with a target gas, and they partially or completely ablate over a short distance. An array of diagnostics then measure, with timing and spatial resolution, the charge and light that is generated in the ablation process. In this thesis, we present results from the newly developed ablation facility. The ionization coefficient, an important parameter for interpreting meteor radar measurements, is measured for various target gases. Furthermore, experimental ablation measurements are compared to predictions from commonly used ablation models. In light of these measurements, implications to the broader context of meteor ablation are discussed.

Percutaneous Microwave Ablation of Renal Angiomyolipomas.

PubMed

Cristescu, Mircea; Abel, E Jason; Wells, Shane; Ziemlewicz, Timothy J; Hedican, Sean P; Lubner, Megan G; Hinshaw, J Louis; Brace, Christopher L; Lee, Fred T

2016-03-01

To evaluate the safety and efficacy of US-guided percutaneous microwave (MW) ablation in the treatment of renal angiomyolipoma (AML). From 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. All 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(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(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. Our 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.

Efficacy and Safety of Radiofrequency Ablation for Focal Hepatic Lesions Adjacent to Gallbladder: Reconfiguration of the Ablation Zone through Probe Relocation and Ablation Time Reduction.

PubMed

Choi, In Young; Kim, Pyo Nyun; Lee, Sung Gu; Won, Hyung Jin; Shin, Yong Moon

2017-10-01

To evaluate the safety and efficacy of radiofrequency (RF) ablation for treatment of focal hepatic lesions adjacent to the gallbladder with electrode relocation and ablation time reduction. Thirty-nine patients who underwent RF ablation for focal hepatic lesions adjacent to the gallbladder (≤ 10 mm) were evaluated retrospectively from January 2011 to December 2014 (30 men and 9 women; age range, 51-85 y; mean age, 65 y). Of 36 patients with hepatocellular carcinoma, 3 had a second treatment for recurrence (mean tumor size, 15 mm ± 6). Patients were divided into 2 subgroups based on lesion distance from the gallbladder: nonabutting (> 5 mm; n = 19) and abutting (≤ 5 mm; n = 20). Electrodes were inserted parallel to the gallbladder through the center of a tumor in the nonabutting group and through the center of the expected ablation zone between a 5-mm safety zone on the liver side and the gallbladder in the abutting group. Ablation time was decreased in proportion to the transverse diameter of the expected ablation zone. Technical success and technical effectiveness rates were 89.7% and 97.4%, respectively, with no significant differences between groups (P = 1.00). Local tumor progression was observed in 3 patients (1 in the nonabutting group and 2 in the abutting group; P = 1.00). There were no major complications. The gallbladder was thickened in 10 patients, with no significant difference between groups (P = .72). Biloma occurred in 1 patient in the nonabutting group. RF ablation with electrode relocation and reduction of ablation time can be a safe and effective treatment for focal hepatic lesions adjacent to the gallbladder. Copyright © 2017 SIR. Published by Elsevier Inc. All rights reserved.

Radiofrequency catheter ablation versus balloon cryoablation of atrial fibrillation: markers of myocardial damage, inflammation, and thrombogenesis.

PubMed

Antolič, Bor; Pernat, Andrej; Cvijić, Marta; Žižek, David; Jan, Matevž; Šinkovec, Matjaž

2016-07-01

Evidence from animal and human studies suggests that cryoablation might be associated with a lesser inflammatory response and activation of coagulation compared with radiofrequency ablation. The study was aimed at comparing the effect of cryoballoon and radiofrequency catheter ablation of paroxysmal atrial fibrillation on markers of myocardial damage, inflammation, and activation of coagulation. Forty-one patients received either cryoballoon (n = 23) or radiofrequency (n = 18) ablation of atrial fibrillation. We measured troponin I, high-sensitivity CRP, and interleukin 6 at baseline from the cubital vein, and from the right and left atrium before and after ablation, and from the cubital vein the following day. Prothrombin fragments 1 + 2, soluble P‑selectin, and D‑dimer were measured before and after ablation from both atria. We observed higher troponin I release in the cryoballoon than in the radiofrequency group (7.01 mcg/l (interquartile range [IQR]: 5.30-9.09) vs 2.32 mcg/l (IQR: 1.45-2.98), p < 0.001). The levels of inflammatory markers (high-sensitivity CRP and interleukin 6) in the two groups were comparable, as were the levels of markers of coagulation activation. Procedure duration, fluoroscopy times, and mid-term success (23 months, IQR 7-32) of the two groups were also comparable. Cryoballoon ablation of atrial fibrillation causes more significant myocardial damage, that is, more extensive ablation lesions, compared with radiofrequency catheter ablation. However, no major differences between these two ablation techniques with regard to the inflammatory response and activation of the coagulation system were observed.

Numerical analysis of laser ablation and damage in glass with multiple picosecond laser pulses.

PubMed

Sun, Mingying; Eppelt, Urs; Russ, Simone; Hartmann, Claudia; Siebert, Christof; Zhu, Jianqiang; Schulz, Wolfgang

2013-04-08

This study presents a novel numerical model for laser ablation and laser damage in glass including beam propagation and nonlinear absorption of multiple incident ultrashort laser pulses. The laser ablation and damage in the glass cutting process with a picosecond pulsed laser was studied. The numerical results were in good agreement with our experimental observations, thereby revealing the damage mechanism induced by laser ablation. Beam propagation effects such as interference, diffraction and refraction, play a major role in the evolution of the crater structure and the damage region. There are three different damage regions, a thin layer and two different kinds of spikes. Moreover, the electronic damage mechanism was verified and distinguished from heat modification using the experimental results with different pulse spatial overlaps.

Assessing glacier melt contribution to streamflow at Universidad Glacier, central Andes of Chile

NASA Astrophysics Data System (ADS)

Bravo, Claudio; Loriaux, Thomas; Rivera, Andrés; Brock, Ben W.

2017-07-01

Glacier melt is an important source of water for high Andean rivers in central Chile, especially in dry years, when it can be an important contributor to flows during late summer and autumn. However, few studies have quantified glacier melt contribution to streamflow in this region. To address this shortcoming, we present an analysis of meteorological conditions and ablation for Universidad Glacier, one of the largest valley glaciers in the central Andes of Chile at the head of the Tinguiririca River, for the 2009-2010 ablation season. We used meteorological measurements from two automatic weather stations installed on the glacier to drive a distributed temperature-index and runoff routing model. The temperature-index model was calibrated at the lower weather station site and showed good agreement with melt estimates from an ablation stake and sonic ranger, and with a physically based energy balance model. Total modelled glacier melt is compared with river flow measurements at three sites located between 0.5 and 50 km downstream. Universidad Glacier shows extremely high melt rates over the ablation season which may exceed 10 m water equivalent in the lower ablation area, representing between 10 and 13 % of the mean monthly streamflow at the outlet of the Tinguiririca River Basin between December 2009 and March 2010. This contribution rises to a monthly maximum of almost 20 % in March 2010, demonstrating the importance of glacier runoff to streamflow, particularly in dry years such as 2009-2010. The temperature-index approach benefits from the availability of on-glacier meteorological data, enabling the calculation of the local hourly variable lapse rate, and is suited to high melt regimes, but would not be easily applicable to glaciers further north in Chile where sublimation is more significant.

Accessory atrioventricular pathways refractory to catheter ablation: role of percutaneous epicardial approach.

PubMed

Scanavacca, Maurício Ibrahim; Sternick, Eduardo Back; Pisani, Cristiano; Lara, Sissy; Hardy, Carina; d'Ávila, André; Correa, Frederico Soares; Darrieux, Francisco; Hachul, Denise; Marcial, Miguel Barbero; Sosa, Eduardo A

2015-02-01

Epicardial mapping and ablation of accessory pathways through a subxiphoid approach can be an alternative when endocardial or epicardial transvenous mapping has failed. We reviewed acute and long-term follow-up of 21 patients (14 males) referred for percutaneous epicardial accessory pathway ablation. There was a median of 2 previous failed procedures. All patients were highly symptomatic, 8 had atrial fibrillation (3 with cardiac arrest) and 13 had frequent symptomatic episodes of atrioventricular reentrant tachycardia. Six patients (28.5%) had a successful epicardial ablation. Five patients (23.8%) underwent a successful repeated endocardial mapping, and ablation after epicardial mapping yielded no early activation site. Epicardial mapping was helpful in guiding endocardial ablation in 2 patients (9.5%), showing that the earliest activation was simultaneous at the epicardium and endocardium. Four patients (19%) underwent successful open-chest surgery after failing epicardial/endocardial ablation. Two patients (9.5%) remained controlled under antiarrhythmic drugs after unsuccessful endocardial/epicardial ablation. Two patients had a coronary sinus diverticulum and one a right atrium to right ventricle diverticulum. Three patients acquired postablation coronary sinus stenosis. There was no major complication related to pericardial access. Percutaneous epicardial approach is an alternative when conventional endocardial or transvenous epicardial ablation fails in the elimination of the accessory pathway. A new attempt by endocardial approach was successful in a significant number of patients. Open-chest surgery may be required in symptomatic cases refractory to endocardial-epicardial approach. © 2014 American Heart Association, Inc.

Temporal trends of in-hospital complications associated with catheter ablation of atrial fibrillation in the United States: An update from Nationwide Inpatient Sample database (2011-2014).

PubMed

Tripathi, Byomesh; Arora, Shilpkumar; Kumar, Varun; Abdelrahman, Mohamed; Lahewala, Sopan; Dave, Mihir; Shah, Mahek; Tan, Bryan; Savani, Sejal; Badheka, Apurva; Gopalan, Radha; Shantha, Ghanshyam Palamaner Subash; Viles-Gonzalez, Juan; Deshmukh, Abhishek

2018-05-01

Catheter ablation is widely accepted intervention for atrial fibrillation (AF) refractory to antiarrhythmic drugs, but limited data are available regarding contemporary trends in major complications and in-hospital mortality due to the procedure. This study was aimed at exploring the temporal trends of in-hospital mortality, major complications, and impact of hospital volume on frequency of AF ablation-related outcomes. The Nationwide Inpatient Sample database was utilized to identify the AF patients treated with catheter ablation. In-hospital death and common complications including vascular access complications, cardiac perforation and/or tamponade, pneumothorax, stroke, and transient ischemic attack, were identified using International Classification of Disease (ICD-9-CM) codes. In-hospital mortality rate of 0.15% and overall complication rate of 5.46% were noted among AF ablation recipients (n = 50,969). Significant increase in complications during study period (relative increase 56.37%, P-trend < 0.001) was observed. Cardiac (2.65%), vascular (1.33%), and neurological (1.05%) complications were most common. On multivariate analysis (odds ratio [OR]; 95% confidence interval [95% CI]; P value), significant predictors of complications were female sex (OR = 1.40; CI = 1.17-1.68; P value < 0.001), high burden of comorbidity as indicated by Charlson Comorbidity Index ≥2 (OR = 2.84; CI = 2.29-3.52; P value < 0.001), and low hospital volume (< 50 procedures). Our study noted a decline in AF ablation-related hospitalizations and complications associated with the procedure. These findings largely reflect shifting trends of outpatient performance of the procedure and increasing safety profile due to improved institutional expertise and catheter techniques. © 2018 Wiley Periodicals, Inc.

Brachial Plexus Injury from CT-Guided RF Ablation Under General Anesthesia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shankar, Sridhar, E-mail: shankars@ummhc.org; Sonnenberg, Eric van; Silverman, Stuart G.

2005-06-15

Brachial plexus injury in a patient under general anesthesia (GA) is not uncommon, despite careful positioning and, particularly, awareness of the possibility. The mechanism of injury is stretching and compression of the brachial plexus over a prolonged period. Positioning the patient within the computed tomography (CT) gantry for abdominal or chest procedures can simulate a surgical procedure, particularly when GA is used. The potential for brachial plexus injury is increased if the case is prolonged and the patient's arms are raised above the head to avoid CT image degradation from streak artifacts. We report a case of profound brachial plexusmore » palsy following a CT-guided radiofrequency ablation procedure under GA. Fortunately, the patient recovered completely. We emphasize the mechanism of injury and detail measures to combat this problem, such that radiologists are aware of this potentially serious complication.« less

On the size and velocity distribution of cosmic dust particles entering the atmosphere

PubMed Central

Carrillo‐Sánchez, J. D.; Feng, W.; Nesvorný, D.; Janches, D.

2015-01-01

Abstract The size and velocity distribution of cosmic dust particles entering the Earth's atmosphere is uncertain. Here we show that the relative concentrations of metal atoms in the upper mesosphere, and the surface accretion rate of cosmic spherules, provide sensitive probes of this distribution. Three cosmic dust models are selected as case studies: two are astronomical models, the first constrained by infrared observations of the Zodiacal Dust Cloud and the second by radar observations of meteor head echoes; the third model is based on measurements made with a spaceborne dust detector. For each model, a Monte Carlo sampling method combined with a chemical ablation model is used to predict the ablation rates of Na, K, Fe, Mg, and Ca above 60 km and cosmic spherule production rate. It appears that a significant fraction of the cosmic dust consists of small (<5 µg) and slow (<15 km s−1) particles. PMID:27478282

Evolutionary Origin of Body Axis Segmentation in Annelids and Arthropods

NASA Technical Reports Server (NTRS)

Shankland, S. Martin

2003-01-01

During the period of this report, we have made a number of important discoveries. To date this work has led to 4 peer-reviewed publications in primary research journals plus 1 minireview and 1 chapter in the proceedings of a meeting. Publications resulting from this grant support are enumerated at the end of the report. Two additional, on-going studies also described. 1. Using laser cell ablation, we have obtained evidence that an annelid - the leech Helobdella robusta - patterns the anteroposterior (AP) polarity of its nascent segment primordia independent of cell interactions oriented along the AP axis. 2. We cloned a Helobdella homologue (hro-hh) of the Drosophila segment polarity gene hedgehog, and used in situ hybridization and northern blots to characterize its expression in the embryo. 3. We have used laser cell ablations to examine the possible role of cell interactions during the developmental patterning of the 4 rostralmost "head" segments of the leech Helobdella robusta.

Initial experience of EUS-guided radiofrequency ablation of unresectable pancreatic cancer.

PubMed

Song, Tae Jun; Seo, Dong Wan; Lakhtakia, Sundeep; Reddy, Nageshwar; Oh, Dong Wook; Park, Do Hyun; Lee, Sang Soo; Lee, Sung Koo; Kim, Myung-Hwan

2016-02-01

Radiofrequency ablation (RFA) has been used as a valuable treatment modality for various unresectable malignancies. EUS-guided radiofrequency ablation (EUS-RFA) of the porcine pancreas was reported to be feasible and safe in our previous study, suggesting that EUS-RFA may be applicable as an adjunct and effective alternative treatment method for unresectable pancreatic cancer. This study aimed to assess the technical feasibility and safety of EUS-RFA for unresectable pancreatic cancer. An 18-gauge endoscopic RFA electrode and a radiofrequency generator were used for the procedure. The length of the exposed tip of the RFA electrode was 10 mm. After insertion of the RFA electrode into the mass, the radiofrequency generator was activated to deliver 20 to 50 W ablation power for 10 seconds. Depending on tumor size, the procedure was repeated to sufficiently cover the tumor. EUS-RFA was performed successfully in all 6 patients (median age 62 years, range 43-73 years). Pancreatic cancer was located in the head (n = 4) or body (n = 2) of the pancreas. The median diameter of masses was 3.8 cm (range 3cm-9cm). Four patients had stage 3 disease, and 2 patients had stage 4 disease. After the procedure, 2 patients experienced mild abdominal pain, but there were no other adverse events such as pancreatitis or bleeding. EUS-RFA could be a technically feasible and safe option for patients with unresectable pancreatic cancer. Copyright © 2016 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

New advances in focal therapy for early stage prostate cancer.

PubMed

Tay, Kae Jack; Schulman, Ariel A; Sze, Christina; Tsivian, Efrat; Polascik, Thomas J

2017-08-01

Prostate focal therapy offers men the opportunity to achieve oncological control while preserving sexual and urinary function. The prerequisites for successful focal therapy are to accurately identify, localize and completely ablate the clinically significant cancer(s) within the prostate. We aim to evaluate the evidence for current and upcoming technologies that could shape the future of prostate cancer focal therapy in the next five years. Areas covered: Current literature on advances in patient selection using imaging, biopsy and biomarkers, ablation techniques and adjuvant treatments for focal therapy are summarized. A literature search of major databases was performed using the search terms 'focal therapy', 'focal ablation', 'partial ablation', 'targeted ablation', 'image guided therapy' and 'prostate cancer'. Expert commentary: Advanced radiological tools such as multiparametric magnetic resonance imaging (mpMRI), multiparametric ultrasound (mpUS), prostate-specific-membrane-antigen positron emission tomography (PSMA-PET) represent a revolution in the ability to understand cancer function and biology. Advances in ablative technologies now provide a menu of modalities that can be rationalized based on lesion location, size and perhaps in the near future, pre-determined resistance to therapy. However, these need to be carefully studied to establish their safety and efficacy parameters. Adjuvant strategies to enhance focal ablation are under development.

Heat sink effect on tumor ablation characteristics as observed in monopolar radiofrequency, bipolar radiofrequency, and microwave, using ex vivo calf liver model.

PubMed

Pillai, Krishna; Akhter, Javid; Chua, Terence C; Shehata, Mena; Alzahrani, Nayef; Al-Alem, Issan; Morris, David L

2015-03-01

Thermal ablation of liver tumors near large blood vessels is affected by the cooling effect of blood flow, leading to incomplete ablation. Hence, we conducted a comparative investigation of heat sink effect in monopolar (MP) and bipolar (BP) radiofrequency ablation (RFA), and microwave (MW) ablation devices.With a perfused calf liver, the ablative performances (volume, mass, density, dimensions), with and without heat sink, were measured. Heat sink was present when the ablative tip of the probes were 8.0 mm close to a major hepatic vein and absent when >30 mm away. Temperatures (T1 and T2) on either side of the hepatic vein near the tip of the probes, heating probe temperature (T3), outlet perfusate temperature (T4), and ablation time were monitored.With or without heat sink, BP radiofrequency ablated a larger volume and mass, compared with MP RFA or MW ablation, with latter device producing the highest density of tissue ablated. MW ablation produced an ellipsoidal shape while radiofrequency devices produced spheres.Percentage heat sink effect in Bipolar radiofrequency : Mono-polar radiofrequency : Microwave was (Volume) 33:41:22; (mass) 23:56:34; (density) 9.0:26:18; and (relative elipscity) 5.8:12.9:1.3, indicating that BP and MW devices were less affected.Percentage heat sink effect on time (minutes) to reach maximum temperature (W) = 13.28:9.2:29.8; time at maximum temperature (X) is 87:66:16.66; temperature difference (Y) between the thermal probes (T3) and the temperature (T1 + T2)/2 on either side of the hepatic vessel was 100:87:20; and temperature difference between the (T1 + T2)/2 and temperature of outlet circulating solution (T4), Z was 20.33:30.23:37.5.MW and BP radiofrequencies were less affected by heat sink while MP RFA was the most affected. With a single ablation, BP radiofrequency ablated a larger volume and mass regardless of heat sink.

Heat Sink Effect on Tumor Ablation Characteristics as Observed in Monopolar Radiofrequency, Bipolar Radiofrequency, and Microwave, Using Ex Vivo Calf Liver Model

PubMed Central

Pillai, Krishna; Akhter, Javid; Chua, Terence C.; Shehata, Mena; Alzahrani, Nayef; Al-Alem, Issan; Morris, David L.

2015-01-01

Abstract Thermal ablation of liver tumors near large blood vessels is affected by the cooling effect of blood flow, leading to incomplete ablation. Hence, we conducted a comparative investigation of heat sink effect in monopolar (MP) and bipolar (BP) radiofrequency ablation (RFA), and microwave (MW) ablation devices. With a perfused calf liver, the ablative performances (volume, mass, density, dimensions), with and without heat sink, were measured. Heat sink was present when the ablative tip of the probes were 8.0 mm close to a major hepatic vein and absent when >30 mm away. Temperatures (T1 and T2) on either side of the hepatic vein near the tip of the probes, heating probe temperature (T3), outlet perfusate temperature (T4), and ablation time were monitored. With or without heat sink, BP radiofrequency ablated a larger volume and mass, compared with MP RFA or MW ablation, with latter device producing the highest density of tissue ablated. MW ablation produced an ellipsoidal shape while radiofrequency devices produced spheres. Percentage heat sink effect in Bipolar radiofrequency : Mono-polar radiofrequency : Microwave was (Volume) 33:41:22; (mass) 23:56:34; (density) 9.0:26:18; and (relative elipscity) 5.8:12.9:1.3, indicating that BP and MW devices were less affected. Percentage heat sink effect on time (minutes) to reach maximum temperature (W) = 13.28:9.2:29.8; time at maximum temperature (X) is 87:66:16.66; temperature difference (Y) between the thermal probes (T3) and the temperature (T1 + T2)/2 on either side of the hepatic vessel was 100:87:20; and temperature difference between the (T1 + T2)/2 and temperature of outlet circulating solution (T4), Z was 20.33:30.23:37.5. MW and BP radiofrequencies were less affected by heat sink while MP RFA was the most affected. With a single ablation, BP radiofrequency ablated a larger volume and mass regardless of heat sink. PMID:25738477

Nonthermal ablation in the rat brain using focused ultrasound and an ultrasound contrast agent: long-term effects

PubMed Central

McDannold, Nathan; Zhang, Yongzhi; Vykhodtseva, Natalia

2016-01-01

OBJECTIVE Thermal ablation with transcranial MRI-guided focused ultrasound (FUS) is currently under investigation as a less invasive alternative to radiosurgery and resection. A major limitation of the method is that its use is currently restricted to centrally located brain targets. The combination of FUS and a microbubble-based ultrasound contrast agent greatly reduces the ultrasound exposure level needed to ablate brain tissue and could be an effective means to increase the “treatment envelope” for FUS in the brain. This method, however, ablates tissue through a different mechanism: destruction of the microvasculature. It is not known whether nonthermal FUS ablation in substantial volumes of tissue can safely be performed without unexpected effects. The authors investigated this question by ablating volumes in the brains of normal rats. METHODS Overlapping sonications were performed in rats (n = 15) to ablate a volume in 1 hemisphere per animal. The sonications (10-msec bursts at 1 Hz for 60 seconds; peak negative pressure 0.8 MPa) were combined with the ultrasound contrast agent Optison (100 μl/kg). The rats were followed with MRI for 4–9 weeks after FUS, and the brains were examined with histological methods. RESULTS Two weeks after sonication and later, the lesions appeared as cyst-like areas in T2-weighted MR images that were stable over time. Histological examination demonstrated well-defined lesions consisting of a cyst-like cavity that remained lined by astrocytic tissue. Some white matter structures within the sonicated area were partially intact. CONCLUSIONS The results of this study indicate that nonthermal FUS ablation can be used to safely ablate tissue volumes in the brain without unexpected delayed effects. The findings are encouraging for the use of this ablation method in the brain. PMID:26848919

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gillams, Alice, E-mail: alliesorting@gmail.com; Khan, Zahid; Osborn, Peter

2013-06-15

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thompson, Scott M., E-mail: Thompson.scott@mayo.edu; Callstrom, Matthew R., E-mail: callstrom.matthew@mayo.edu; McKusick, Michael A., E-mail: mckusick.michael@mayo.edu

PurposeThe purpose of this study was to determine the feasibility, safety, and early effectiveness of percutaneous image-guided ablation as second-line treatment for symptomatic soft-tissue vascular anomalies (VA).Materials and MethodsAn IRB-approved retrospective review was undertaken of all patients who underwent percutaneous image-guided ablation as second-line therapy for treatment of symptomatic soft-tissue VA during the period from 1/1/2008 to 5/20/2014. US/CT- or MRI-guided and monitored cryoablation or MRI-guided and monitored laser ablation was performed. Clinical follow-up began at one-month post-ablation.ResultsEight patients with nine torso or lower extremity VA were treated with US/CT (N = 4) or MRI-guided (N = 2) cryoablation or MRI-guided laser ablation (N = 5)more » for moderate to severe pain (N = 7) or diffuse bleeding secondary to hemangioma–thrombocytopenia syndrome (N = 1). The median maximal diameter was 9.0 cm (6.5–11.1 cm) and 2.5 cm (2.3–5.3 cm) for VA undergoing cryoablation and laser ablation, respectively. Seven VA were ablated in one session, one VA initially treated with MRI-guided cryoablation for severe pain was re-treated with MRI-guided laser ablation due to persistent moderate pain, and one VA was treated in a planned two-stage session due to large VA size. At an average follow-up of 19.8 months (range 2–62 months), 7 of 7 patients with painful VA reported symptomatic pain relief. There was no recurrence of bleeding at five-year post-ablation in the patient with hemangioma–thrombocytopenia syndrome. There were two minor complications and no major complications.ConclusionImage-guided percutaneous ablation is a feasible, safe, and effective second-line treatment option for symptomatic VA.« less

Percutaneous Radiofrequency Ablation of a Small Renal Mass Complicated by Appendiceal Perforation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boone, Judith, E-mail: j.boone@amc.uva.nl; Bex, Axel, E-mail: a.bex@nki.nl; Prevoo, Warner, E-mail: w.prevoo@nki.nl

2012-06-15

Percutaneous radiofrequency ablation (RFA) has gained wide acceptance as nephron-sparing therapy for small renal masses in select patients. Generally, it is a safe procedure with minor morbidity and acceptable short-term oncologic outcome. However, as a result of the close proximity of vital structures, such as the bowel, ureter, and large vessels, to the ablative field, complications regarding these structures may occur. This is the first article describing appendiceal perforation as a complication of computed tomography-guided RFA despite hydrodissection. When performing this innovative and promising procedure one should be aware of the possibility of particular minor and even major complications.

Head formation: OTX2 regulates Dkk1 and Lhx1 activity in the anterior mesendoderm.

PubMed

Ip, Chi Kin; Fossat, Nicolas; Jones, Vanessa; Lamonerie, Thomas; Tam, Patrick P L

2014-10-01

The Otx2 gene encodes a paired-type homeobox transcription factor that is essential for the induction and the patterning of the anterior structures in the mouse embryo. Otx2 knockout embryos fail to form a head. Whereas previous studies have shown that Otx2 is required in the anterior visceral endoderm and the anterior neuroectoderm for head formation, its role in the anterior mesendoderm (AME) has not been assessed specifically. Here, we show that tissue-specific ablation of Otx2 in the AME phenocopies the truncation of the embryonic head of the Otx2 null mutant. Expression of Dkk1 and Lhx1, two genes that are also essential for head formation, is disrupted in the AME of the conditional Otx2-deficient embryos. Consistent with the fact that Dkk1 is a direct target of OTX2, we showed that OTX2 can interact with the H1 regulatory region of Dkk1 to activate its expression. Cross-species comparative analysis, RT-qPCR, ChIP-qPCR and luciferase assays have revealed two conserved regions in the Lhx1 locus to which OTX2 can bind to activate Lhx1 expression. Abnormal development of the embryonic head in Otx2;Lhx1 and Otx2;Dkk1 compound mutant embryos highlights the functional intersection of Otx2, Dkk1 and Lhx1 in the AME for head formation. © 2014. Published by The Company of Biologists Ltd.

Limitations of dormant conduction as a predictor of atrial fibrillation recurrence and pulmonary vein reconnection after catheter ablation.

PubMed

Lin, Frank S; Ip, James E; Markowitz, Steven M; Liu, Christopher F; Thomas, George; Lerman, Bruce B; Cheung, Jim W

2015-05-01

Adenosine (ADO) can uncover dormant conduction following pulmonary vein (PV) isolation. We sought to identify the value of dormant conduction for predicting atrial fibrillation (AF) recurrence and chronic PV reconnection. One hundred fifty-two patients (80 male; age 60 ± 11 years) undergoing PV isolation for AF were studied. After PV isolation, sites of ADO-induced PV reconnection were recorded and targeted with additional ablation. In patients undergoing repeat ablation for recurrent AF, chronic PV reconnection was assessed. Forty-five (30%) patients had ADO-induced PV reconnection following PV isolation. Dormant conduction was successfully eliminated with additional ablation in 41 (91%) of these patients. After follow-up of 598 ± 270 days, 60 (39%) patients had recurrent AF. Dormant PV conduction was not a significant predictor of AF recurrence (hazard ratio 1.51; 95% confidence interval: 0.89-2.56; P = 0.12) although three of four (75%) patients with residual dormant conduction following initial ablation developed recurrent AF. Twenty-six patients with recurrent AF underwent repeat ablation with 52 of 99 (53%) PVs found to have chronic reconnection. Nine of 11 (82%) PVs with dormant conduction and 43 of 88 (49%) PVs without dormant conduction at initial procedure had chronic reconnection at repeat ablation. When additional ablation is performed to eliminate ADO-induced PV reconnection after PV isolation, dormant conduction is not a significant predictor of recurrent AF. Although PVs with dormant conduction at initial procedure may develop chronic reconnection, the majority of PVs that show conduction recovery at repeat ablation occur in nondormant PVs. © 2015 Wiley Periodicals, Inc.

Ablation Behavior of Plasma-Sprayed La1-xSrxTiO3+δ Coating Irradiated by High-Intensity Continuous Laser.

PubMed

Zhu, Jinpeng; Ma, Zhuang; Gao, Yinjun; Gao, Lihong; Pervak, Vladimir; Wang, Lijun; Wei, Chenghua; Wang, Fuchi

2017-10-11

Laser protection for optical components, particularly those in high-power laser systems, has been a major concern. La 1-x Sr x TiO 3+δ with its good optical and thermal properties can be potentially applied as a high-temperature optical protective coating or high-reflectivity material for optical components. However, the high-power laser ablation behavior of plasma-sprayed La 1-x Sr x TiO 3+δ (x = 0.1) coatings has rarely been investigated. Thus, in this study, laser irradiation experiments were performed to study the effect of high-intensity continuous laser on the ablation behavior of the La 1-x Sr x TiO 3+δ coating. The results show that the La 1-x Sr x TiO 3+δ coating undergoes three ablation stages during laser irradiation: coating oxidation, formation and growth of new structures (columnar and dendritic crystals), and mechanical failure. A finite-element simulation was also conducted to explore the mechanism of the ablation damage to the La 1-x Sr x TiO 3+δ coating and provided a good understanding of the ablation behavior. The apparent ablation characteristics are attributed to the different temperature gradients determined by the reflectivity and thermal diffusivity of the La 1-x Sr x TiO 3+δ coating material, which are critical factors for improving the antilaser ablation property. Now, the stainless steel substrate deposited by it can effectively work as a protective shield layer against ablation by laser irradiation.

The effect of flap thickness on corneal biomechanics after myopic laser in situ keratomileusis using the M-2 microkeratome

PubMed Central

Goussous, Iyad A; El-Agha, Mohamed-Sameh; Awadein, Ahmed; Hosny, Mohamed H; Ghaith, Alaa A; Khattab, Ahmed L

2017-01-01

Purpose The purpose of this study was to determine the effect of flap thickness on corneal biomechanics after myopic laser in situ keratomileusis (LASIK). Methods This is a prospective controlled non-randomized, institutional study. Patients underwent either epi-LASIK with mitomycin (advanced surface ablation [ASA]), thin-flap LASIK (90 µm head), or thick-flap LASIK (130 µm head). In ASA, the Moria Epi-K hydroseparator was used. LASIK flaps were created using the Moria M-2 mechanical microkeratome. The corneal hysteresis (CH) and corneal resistance factor (CRF) were measured preoperatively and 3 months after surgery, using the Ocular Response Analyzer®. Results Ten patients (19 eyes) underwent ASA, 11 patients (16 eyes) underwent thin-flap LASIK, and 11 patients (16 eyes) underwent thick-flap LASIK. The mean preoperative CH was 10.47±0.88, 10.52±1.4, and 11.28±1.4 mmHg (p=0.043), respectively, decreasing after surgery by 1.75±1.02, 1.66±1.00, and 2.62±1.03 mmHg (p=0.017). The mean reduction of CH per micron of central corneal ablation was 0.031, 0.023, and 0.049 mmHg/µm (p=0.005). Mean preoperative CRF was 10.11±1.28, 10.34±1.87, and 10.62±1.76 mmHg (p=0.66), decreasing after surgery by 2.33±1.35, 2.77±1.03, and 2.92±1.10 mmHg (p=0.308). The mean reduction of CRF per micron of central corneal ablation was 0.039, 0.040, and 0.051 mmHg/µm (p=0.112). Conclusion Thick-flap LASIK caused a greater reduction of CH and CRF than thin-flap LASIK and ASA, although this was statistically significant only for CH. ASA and thin-flap LASIK were found to be biomechanically similar. PMID:29200820

The effect of flap thickness on corneal biomechanics after myopic laser in situ keratomileusis using the M-2 microkeratome.

PubMed

Goussous, Iyad A; El-Agha, Mohamed-Sameh; Awadein, Ahmed; Hosny, Mohamed H; Ghaith, Alaa A; Khattab, Ahmed L

2017-01-01

The purpose of this study was to determine the effect of flap thickness on corneal biomechanics after myopic laser in situ keratomileusis (LASIK). This is a prospective controlled non-randomized, institutional study. Patients underwent either epi-LASIK with mitomycin (advanced surface ablation [ASA]), thin-flap LASIK (90 µm head), or thick-flap LASIK (130 µm head). In ASA, the Moria Epi-K hydroseparator was used. LASIK flaps were created using the Moria M-2 mechanical microkeratome. The corneal hysteresis (CH) and corneal resistance factor (CRF) were measured preoperatively and 3 months after surgery, using the Ocular Response Analyzer ® . Ten patients (19 eyes) underwent ASA, 11 patients (16 eyes) underwent thin-flap LASIK, and 11 patients (16 eyes) underwent thick-flap LASIK. The mean preoperative CH was 10.47±0.88, 10.52±1.4, and 11.28±1.4 mmHg ( p =0.043), respectively, decreasing after surgery by 1.75±1.02, 1.66±1.00, and 2.62±1.03 mmHg ( p =0.017). The mean reduction of CH per micron of central corneal ablation was 0.031, 0.023, and 0.049 mmHg/µm ( p =0.005). Mean preoperative CRF was 10.11±1.28, 10.34±1.87, and 10.62±1.76 mmHg ( p =0.66), decreasing after surgery by 2.33±1.35, 2.77±1.03, and 2.92±1.10 mmHg ( p =0.308). The mean reduction of CRF per micron of central corneal ablation was 0.039, 0.040, and 0.051 mmHg/µm ( p =0.112). Thick-flap LASIK caused a greater reduction of CH and CRF than thin-flap LASIK and ASA, although this was statistically significant only for CH. ASA and thin-flap LASIK were found to be biomechanically similar.

Green and Fast Laser Fusion Technique for Bulk Silicate Rock Analysis by Laser Ablation-Inductively Coupled Plasma Mass Spectrometry.

PubMed

Zhang, Chenxi; Hu, Zhaochu; Zhang, Wen; Liu, Yongsheng; Zong, Keqing; Li, Ming; Chen, Haihong; Hu, Shenghong

2016-10-18

Sample preparation of whole-rock powders is the major limitation for their accurate and precise elemental analysis by laser ablation inductively-coupled plasma mass spectrometry (ICPMS). In this study, a green, efficient, and simplified fusion technique using a high energy infrared laser was developed for major and trace elemental analysis. Fusion takes only tens of milliseconds for each sample. Compared to the pressed pellet sample preparation, the analytical precision of the developed laser fusion technique is higher by an order of magnitude for most elements in granodiorite GSP-2. Analytical results obtained for five USGS reference materials (ranging from mafic to intermediate to felsic) using the laser fusion technique generally agree with recommended values with discrepancies of less than 10% for most elements. However, high losses (20-70%) of highly volatile elements (Zn and Pb) and the transition metal Cu are observed. The achieved precision is within 5% for major elements and within 15% for most trace elements. Direct laser fusion of rock powders is a green and notably simple method to obtain homogeneous samples, which will significantly accelerate the application of laser ablation ICPMS for whole-rock sample analysis.

Microwave ablation for thyroid nodules: a new string to the bow for percutaneous treatments?

PubMed

Morelli, Francesco; Sacrini, Andrea; Pompili, Giovanni; Borelli, Anna; Panella, Silvia; Masu, Annamaria; De Pasquale, Loredana; Giacchero, Roberta; Carrafiello, Gianpaolo

2016-12-01

Thyroid nodules are a fairly common finding in general population and, even if most of them are benign, a treatment can be however necessary. In the last years, non surgical minimally invasive techniques have been developed to treat this pathology, starting from percutaneous ethanol injection (PEI), to laser ablation (LA), radiofrequency ablation (RFA) and, most recently, microwave ablation (MWA). We reviewed all medical literature searching in pubmed.gov the terms "microwave" & "thyroid". We found three original studies concerning MWA treatment, for a total of 263 patients (mean age 51.0 years; range, 15-80 years; male to female ratio 2.55) and 522 nodules. A total of 522 nodules (338 solid, 22 cystic, 162 mixed) in 263 patients were treated. Studies have shown a mean reduction in volume of thyroid nodules ranging from 45.9% to 65%. No study reported a significant and definitive change in laboratory parameters, except for one case (Heck et al. ). No studies have reported major complications after procedure. MWA is a new, promising technique among the minimally invasive treatments of thyroid nodules. Actually, the larger diameter of MW antenna seems to be the major limiting factor in the use of this technique. More studies are necessary to evaluate feasibility, safety and efficacy of the procedure.

Comparative Proteomic Analysis of Normal and Collagen IX Null Mouse Cartilage Reveals Altered Extracellular Matrix Composition and Novel Components of the Collagen IX Interactome*

PubMed Central

Brachvogel, Bent; Zaucke, Frank; Dave, Keyur; Norris, Emma L.; Stermann, Jacek; Dayakli, Münire; Koch, Manuel; Gorman, Jeffrey J.; Bateman, John F.; Wilson, Richard

2013-01-01

The cartilage extracellular matrix is essential for endochondral bone development and joint function. In addition to the major aggrecan/collagen II framework, the interacting complex of collagen IX, matrilin-3, and cartilage oligomeric matrix protein (COMP) is essential for cartilage matrix stability, as mutations in Col9a1, Col9a2, Col9a3, Comp, and Matn3 genes cause multiple epiphyseal dysplasia, in which patients develop early onset osteoarthritis. In mice, collagen IX ablation results in severely disturbed growth plate organization, hypocellular regions, and abnormal chondrocyte shape. This abnormal differentiation is likely to involve altered cell-matrix interactions but the mechanism is not known. To investigate the molecular basis of the collagen IX null phenotype we analyzed global differences in protein abundance between wild-type and knock-out femoral head cartilage by capillary HPLC tandem mass spectrometry. We identified 297 proteins in 3-day cartilage and 397 proteins in 21-day cartilage. Components that were differentially abundant between wild-type and collagen IX-deficient cartilage included 15 extracellular matrix proteins. Collagen IX ablation was associated with dramatically reduced COMP and matrilin-3, consistent with known interactions. Matrilin-1, matrilin-4, epiphycan, and thrombospondin-4 levels were reduced in collagen IX null cartilage, providing the first in vivo evidence for these proteins belonging to the collagen IX interactome. Thrombospondin-4 expression was reduced at the mRNA level, whereas matrilin-4 was verified as a novel collagen IX-binding protein. Furthermore, changes in TGFβ-induced protein βig-h3 and fibronectin abundance were found in the collagen IX knock-out but not associated with COMP ablation, indicating specific involvement in the abnormal collagen IX null cartilage. In addition, the more widespread expression of collagen XII in the collagen IX-deficient cartilage suggests an attempted compensatory response to the absence of collagen IX. Our differential proteomic analysis of cartilage is a novel approach to identify candidate matrix protein interactions in vivo, underpinning further analysis of mutant cartilage lacking other matrix components or harboring disease-causing mutations. PMID:23530037

Novel Approaches for the Treatment of the Patient with Resistant Hypertension: Renal Nerve Ablation

PubMed Central

Gulati, Vinay; White, William B.

2013-01-01

Sympathetic innervation of the kidneys plays a major role in the pathogenesis of hypertension through modulation of renin secretion, glomerular filtration rate and renal absorption of sodium. Targeted interventions for renal nerve ablation are being developed for treatment of drug resistant hypertension in the USA and rest of the world. Early studies with the use of radiofrequency based renal denervation systems have shown encouraging results with significant reduction of blood pressure in patients inadequately controlled despite nearly maximal drug therapy regimens. Thus far, the renal denervation procedure has been associated with minimal side effects. Long term efficacy and safety beyond 3 years needs to be determined for renal nerve ablation. This review focuses on the physiology of the renal sympathetic system, the rationale for renal nerve ablation and current evidence in support of the available therapeutic renal denervation systems. PMID:24244757

Assessment of InfraScanner 2000™ in Detecting Subdural and Epidural Hematomas

ClinicalTrials.gov

2018-05-18

Head Trauma; Craniocerebral Injuries; Crushing Skull Injury; Head Injuries; Head Injuries, Multiple; Head Injuries, Closed; Head Trauma,Closed; Head Trauma Injury; Head Trauma, Penetrating; Head Injury, Minor; Head Injury Major; Head Injury, Open; Injuries, Craniocerebral; Injuries, Head; Multiple Head Injury; Trauma, Head

Vertigo Perception and Quality of Life in Patients after Surgical Treatment of Vestibular Schwannoma with Pretreatment Prehabituation by Chemical Vestibular Ablation

PubMed Central

Balatková, Zuzana; Chovanec, Martin; Čakrt, Ondřej; Hrubá, Silvie; Jeřábek, Jaroslav; Zvěřina, Eduard; Profant, Oliver; Fík, Zdeněk; Komarc, Martin; Kluh, Jan; Černý, Rudolf

2016-01-01

Surgical removal of vestibular schwannoma causes acute vestibular symptoms, including postoperative vertigo and oscillopsia due to nystagmus. In general, the dominant symptom postoperatively is vertigo. Preoperative chemical vestibular ablation can reduce vestibular symptoms postoperatively. We used 1.0 mL of 40 mg/mL nonbuffered gentamicin in three intratympanic installations over 2 days, 2 months preoperatively in 10 patients. Reduction of vestibular function was measured by the head impulse test and the caloric test. Reduction of vestibular function was found in all gentamicin patient groups. After gentamicin vestibular ablation, patients underwent home vestibular exercising for two months. The control group consisted of 10 patients who underwent only home vestibular training two months preoperatively. Postoperative rates of recovery and vertigo in both groups were evaluated with the Glasgow Benefit Inventory (GBI), the Glasgow Health Status Inventory (GHSI), and the Dizziness Handicap Inventory questionnaires, as well as survey of visual symptoms by specific questionnaire developed by us. There were no statistically significant differences between both groups with regard to the results of questionnaires. Patients who received preoperative gentamicin were more resilient to optokinetic and optic flow stimulation (p < 0.05). This trial is registered with clinical study registration number NCT02963896. PMID:28053986

Vertigo Perception and Quality of Life in Patients after Surgical Treatment of Vestibular Schwannoma with Pretreatment Prehabituation by Chemical Vestibular Ablation.

PubMed

Čada, Zdeněk; Balatková, Zuzana; Chovanec, Martin; Čakrt, Ondřej; Hrubá, Silvie; Jeřábek, Jaroslav; Zvěřina, Eduard; Profant, Oliver; Fík, Zdeněk; Komarc, Martin; Betka, Jan; Kluh, Jan; Černý, Rudolf

2016-01-01

Surgical removal of vestibular schwannoma causes acute vestibular symptoms, including postoperative vertigo and oscillopsia due to nystagmus. In general, the dominant symptom postoperatively is vertigo. Preoperative chemical vestibular ablation can reduce vestibular symptoms postoperatively. We used 1.0 mL of 40 mg/mL nonbuffered gentamicin in three intratympanic installations over 2 days, 2 months preoperatively in 10 patients. Reduction of vestibular function was measured by the head impulse test and the caloric test. Reduction of vestibular function was found in all gentamicin patient groups. After gentamicin vestibular ablation, patients underwent home vestibular exercising for two months. The control group consisted of 10 patients who underwent only home vestibular training two months preoperatively. Postoperative rates of recovery and vertigo in both groups were evaluated with the Glasgow Benefit Inventory (GBI), the Glasgow Health Status Inventory (GHSI), and the Dizziness Handicap Inventory questionnaires, as well as survey of visual symptoms by specific questionnaire developed by us. There were no statistically significant differences between both groups with regard to the results of questionnaires. Patients who received preoperative gentamicin were more resilient to optokinetic and optic flow stimulation ( p < 0.05). This trial is registered with clinical study registration number NCT02963896.

Irreversible electroporation of the pancreas is feasible and safe in a porcine survival model.

PubMed

Fritz, Stefan; Sommer, Christof M; Vollherbst, Dominik; Wachter, Miguel F; Longerich, Thomas; Sachsenmeier, Milena; Knapp, Jürgen; Radeleff, Boris A; Werner, Jens

2015-07-01

Use of thermal tumor ablation in the pancreatic parenchyma is limited because of the risk of pancreatitis, pancreatic fistula, or hemorrhage. This study aimed to evaluate the feasibility and safety of irreversible electroporation (IRE) in a porcine model. Ten pigs were divided into 2 study groups. In the first group, animals received IRE of the pancreatic tail and were killed after 60 minutes. In the second group, animals received IRE at the head of the pancreas and were followed up for 7 days. Clinical parameters, computed tomography imaging, laboratory results, and histology were obtained. All animals survived IRE ablation, and no cardiac adverse effects were noted. Sixty minutes after IRE, a hypodense lesion on computed tomography imaging indicated the ablation zone. None of the animals developed clinical signs of acute pancreatitis. Only small amounts of ascites fluid, with a transient increase in amylase and lipase levels, were observed, indicating that no pancreatic fistula occurred. This porcine model shows that IRE is feasible and safe in the pancreatic parenchyma. Computed tomography imaging reveals significant changes at 60 minutes after IRE and therefore might serve as an early indicator of therapeutic success. Clinical studies are needed to evaluate the efficacy of IRE in pancreatic cancer.

Safety and Long-Term Outcomes of Catheter Ablation of Atrial Fibrillation Using Magnetic Navigation versus Manual Conventional Ablation: A Propensity-Score Analysis.

PubMed

Adragão, Pedro Pulido; Cavaco, Diogo; Ferreira, António Miguel; Costa, Francisco Moscoso; Parreira, Leonor; Carmo, Pedro; Morgado, Francisco Bello; Santos, Katya Reis; Santos, Pedro Galvão; Carvalho, Maria Salomé; Durazzo, Anai; Marques, Hugo; Gonçalves, Pedro Araújo; Raposo, Luís; Mendes, Miguel

2016-03-01

Whether or not the potential advantages of using a magnetic navigation system (MNS) translate into improved outcomes in patients undergoing atrial fibrillation (AF) ablation is a question that remains unanswered. In this observational registry study, we used propensity-score matching to compare the outcomes of patients with symptomatic drug-refractory AF who underwent catheter ablation using MNS with the outcomes of those who underwent catheter ablation using conventional manual navigation. Among 1,035 eligible patients, 287 patients in each group had similar propensity scores and were included in the analysis. The primary efficacy outcome was the rate of AF relapse after a 3-month blanking period. At a mean follow-up of 2.6 ± 1.5 years, AF ablation with MNS was associated with a similar risk of AF relapse as compared with manual navigation (18.4% per year and 22.3% per year, respectively; hazard ratio 0.81, 95% CI 0.63-1.05; P = 0.108). Major complications occurred in two patients (0.7%) using MNS, and in six patients (2.1%) undergoing manually navigated ablation (P = 0.286). Fluoroscopy times were 21 ± 10 minutes in the manual navigation group, and 12 ± 9 minutes in the MNS group (P < 0.001), whereas total procedure times were 152 ± 52 minutes and 213 ± 58 minutes, respectively (P < 0.001). In this propensity-score matched comparison, magnetic navigation and conventional manual AF ablations seem to have similar relapse rates and a similar risk of complications. AF ablations with magnetic navigation take longer to perform but expose patients to significantly shorter fluoroscopy times. © 2015 Wiley Periodicals, Inc.

Value of microwave ablation in treatment of large lesions of hepatocellular carcinoma.

PubMed

Medhat, Eman; Abdel Aziz, Ashraf; Nabeel, Mohammed; Elbaz, Tamer; Zakaria, Zeinab; Shousha, Hend; Amer, Ayman; Fouad Fathalah, Waleed; Maher, Rabab; Musa, Shereif

2015-08-01

Thermal ablative therapies continue to be favored as a safe and effective treatment for patients with non-resectable hepatocellular carcinoma (HCC). Percutaneous microwave ablative therapy, which is a relatively new technique, has the advantage in providing faster ablation of large tumors. This study aimed to evaluate microwave ablation in the treatment of large HCC (5-7 cm) and to assess its effect on local tumor progression, prognostic outcome and patients' survival. In all, 26 patients with large HCC lesions (5-7 cm) were managed in the multidisciplinary clinic of Kasr Al Ainy University hospital using microwave ablation. The treatment was performed with the patient under conscious sedation and analgesia and ultrasonography-guided using an HS AMICA microwave machine operating at frequency of 2450 MHz and a power up to 100 W. Multiple needle insertions were made in one or two sessions according to the size of the lesion. The complete ablation rate, local tumor progression and patients' overall survival were analyzed, and the efficacy and safety of MWA was evaluated. Complete ablation was achieved in 19/26 (73.1%). Local tumor progression was recorded in five treated lesions (19.2%). Distant tumor progression within the liver was recorded in six patients (23.1%), with a mean survival of 21.5 months. No procedure-related major complications or deaths were observed. Percutaneous microwave ablation is safe and effective in the treatment of large HCC tumors. Patients' survival and local tumor control were acceptable. © 2015 Chinese Medical Association Shanghai Branch, Chinese Society of Gastroenterology, Renji Hospital Affiliated to Shanghai Jiaotong University School of Medicine and Wiley Publishing Asia Pty Ltd.

Contact force monitoring during catheter ablation of intraatrial reentrant tachycardia in patients with congenital heart disease.

PubMed

Krause, Ulrich; Backhoff, David; Klehs, Sophia; Schneider, Heike E; Paul, Thomas

2016-08-01

Monitoring of catheter contact force during catheter ablation of atrial fibrillation has been shown to increase efficacy and safety. However, almost no data exists on the use of this technology in catheter ablation of intraatrial reentrant tachycardia in patients with congenital heart disease. The aim of the present study was to evaluate the impact of contact force monitoring during catheter ablation of intraatrial reentrant tachycardia in those patients. Catheter ablation of intraatrial reentrant tachycardia using monitoring of catheter contact force was performed in 28 patients with congenital heart disease (CHD). Thirty-two patients matched according to gender, age, and body weight with congenital heart disease undergoing catheter ablation without contact force monitoring served as control group. Parameters reflecting acute procedural success, long-term efficacy, and safety were compared. Acute procedural success was statistically not different in both groups (contact force 93 % vs. control 84 %, p = 0.3). Likewise the recurrence rate 1 year after ablation as shown by Kaplan-Meier analysis did not differ (contact force 28 % vs. control 37 %, p = 0.63). Major complications were restricted to groin vessel injuries and occurred in 3 out of 60 patients (contact force n = 1; control n = 2). Complications related to excessive catheter contact force were not observed. The present study did not show superiority of catheter contact force monitoring during ablation of intraatrial reentrant tachycardia in patients with CHD in terms of efficacy and safety. Higher contact force compared to pulmonary vein isolation might therefore be required to increase the efficacy of catheter ablation of intraatrial reentrant tachycardia in patients with congenital heart disease.

Optimal contact forces to minimize cardiac perforations before, during, and/or after radiofrequency or cryothermal ablations.

PubMed

Quallich, Stephen G; Van Heel, Michael; Iaizzo, Paul A

2015-02-01

Catheter perforations remain a major clinical concern during ablation procedures for treatment of atrial arrhythmias and may lead to life-threatening cardiac tamponade. Radiofrequency (RF) ablation alters the biomechanical properties of cardiac tissue, ultimately allowing for perforation to occur more readily. Studies on the effects of cryoablation on perforation force as well as studies defining the perforation force of human tissue are limited. The purpose of this study was to investigate the required force to elicit perforation of cardiac atrial tissue after or during ablation procedures. Effects of RF or cryothermal ablations on catheter perforation forces for both swine (n = 83 animals, 530 treatments) and human (n = 8 specimens, 136 treatments) cardiac tissue were investigated. Overall average forces resulting in perforation of healthy unablated tissue were 406g ± 170g for swine and 591g ± 240g for humans. Post-RF ablation applications considerably reduced these forces to 246g ± 118g for swine and 362 ± 185g for humans (P <.001). Treatments with cryoablation did not significantly alter forces required to induce perforations. Decreasing catheter sizes resulted in a reduction in forces required to perforate the atrial wall (P <.001). Catheter perforations occurred over an array of contact forces with a minimum of 38g being observed. The swine model likely underestimates the required perforation forces relative to those of human tissues. We provide novel insights related to the comparative effects of RF and cryothermal ablations on the potential for inducing undesired punctures, with RF ablation reducing perforation force significantly. These data are insightful for physicians performing ablation procedures as well as for medical device designers. Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Radiofrequency ablation of liver tumors (I): biological background.

PubMed

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

2010-01-01

Majority of patients suffering from liver tumors are not candidates for surgery. Currently, minimal invasive techniques have become available for local destruction of hepatic tumors. Radiofrequency ablation is based on biological response to tissue hyperthermia. The aim of this article is to review available biological data on tissue destruction mechanisms. Experimental evidence shows that tissue injury following thermal ablation occurs in two distinct phases. The initial phase is direct injury, which is determined by energy applied, tumor biology, and tumor microenvironment. The temperature varies along the ablation zone and this is reflected by different morphological changes in affected tissues. The local hyperthermia alters metabolism, exacerbates tissue hypoxia, and increases thermosensitivity. The second phase - indirect injury - is observed after the cessation of heat stimulus. This phase represents a balance of several promoting and inhibiting mechanisms, such as induction of apoptosis, heat shock proteins, Kupffer cell activation, stimulation of the immune response, release of cytokines, and ischemia-reperfusion injury. A deeper understanding of the underlying mechanisms may possibly lead to refinements in radiofrequency ablation technology, resulting in advanced local tumor control and prolonged overall survival.

Comparative proteomic analysis of normal and collagen IX null mouse cartilage reveals altered extracellular matrix composition and novel components of the collagen IX interactome.

PubMed

Brachvogel, Bent; Zaucke, Frank; Dave, Keyur; Norris, Emma L; Stermann, Jacek; Dayakli, Münire; Koch, Manuel; Gorman, Jeffrey J; Bateman, John F; Wilson, Richard

2013-05-10

Collagen IX is an integral cartilage extracellular matrix component important in skeletal development and joint function. Proteomic analysis and validation studies revealed novel alterations in collagen IX null cartilage. Matrilin-4, collagen XII, thrombospondin-4, fibronectin, βig-h3, and epiphycan are components of the in vivo collagen IX interactome. We applied a proteomics approach to advance our understanding of collagen IX ablation in cartilage. The cartilage extracellular matrix is essential for endochondral bone development and joint function. In addition to the major aggrecan/collagen II framework, the interacting complex of collagen IX, matrilin-3, and cartilage oligomeric matrix protein (COMP) is essential for cartilage matrix stability, as mutations in Col9a1, Col9a2, Col9a3, Comp, and Matn3 genes cause multiple epiphyseal dysplasia, in which patients develop early onset osteoarthritis. In mice, collagen IX ablation results in severely disturbed growth plate organization, hypocellular regions, and abnormal chondrocyte shape. This abnormal differentiation is likely to involve altered cell-matrix interactions but the mechanism is not known. To investigate the molecular basis of the collagen IX null phenotype we analyzed global differences in protein abundance between wild-type and knock-out femoral head cartilage by capillary HPLC tandem mass spectrometry. We identified 297 proteins in 3-day cartilage and 397 proteins in 21-day cartilage. Components that were differentially abundant between wild-type and collagen IX-deficient cartilage included 15 extracellular matrix proteins. Collagen IX ablation was associated with dramatically reduced COMP and matrilin-3, consistent with known interactions. Matrilin-1, matrilin-4, epiphycan, and thrombospondin-4 levels were reduced in collagen IX null cartilage, providing the first in vivo evidence for these proteins belonging to the collagen IX interactome. Thrombospondin-4 expression was reduced at the mRNA level, whereas matrilin-4 was verified as a novel collagen IX-binding protein. Furthermore, changes in TGFβ-induced protein βig-h3 and fibronectin abundance were found in the collagen IX knock-out but not associated with COMP ablation, indicating specific involvement in the abnormal collagen IX null cartilage. In addition, the more widespread expression of collagen XII in the collagen IX-deficient cartilage suggests an attempted compensatory response to the absence of collagen IX. Our differential proteomic analysis of cartilage is a novel approach to identify candidate matrix protein interactions in vivo, underpinning further analysis of mutant cartilage lacking other matrix components or harboring disease-causing mutations.

Laser ignition of an experimental combustion chamber with a multi-injector configuration at low pressure conditions

NASA Astrophysics Data System (ADS)

Börner, Michael; Manfletti, Chiara; Kroupa, Gerhard; Oschwald, Michael

2017-09-01

In search of reliable and light-weight ignition systems for re-ignitable upper stage engines, a laser ignition system was adapted and tested on an experimental combustion chamber for propellant injection into low combustion chamber pressures at 50-80 mbar. The injector head pattern consisted of five coaxial injector elements. Both, laser-ablation-driven ignition and laser-plasma-driven ignition were tested for the propellant combination liquid oxygen and gaseous hydrogen. The 122 test runs demonstrated the reliability of the ignition system for different ignition configurations and negligible degradation due to testing. For the laser-plasma-driven scheme, minimum laser pulse energies needed for 100% ignition probability were found to decrease when increasing the distance of the ignition location from the injector faceplate with a minimum of 2.6 mJ. For laser-ablation-driven ignition, the minimum pulse energy was found to be independent of the ablation material tested and was about 1.7 mJ. The ignition process was characterized using both high-speed Schlieren and OH* emission diagnostics. Based on these findings and on the increased fiber-based pulse transport capabilities recently published, new ignition system configurations for space propulsion systems relying on fiber-based pulse delivery are formulated. If the laser ignition system delivers enough pulse energy, the laser-plasma-driven configuration represents the more versatile configuration. If the laser ignition pulse power is limited, the application of laser-ablation-driven ignition is an option to realize ignition, but implies restrictions concerning the location of ignition.

ULNAR NERVE COMPONENT TO INNERVATION OF THUMB CARPOMETACARPAL JOINT

PubMed Central

Miki, Roberto Augusto; Kam, Check C; Gennis, Elisabeth R; Barkin, Jodie A; Riel, Ryan U; Robinson, Philip G; Owens, Patrick W

2011-01-01

Purpose Thumb carpometacarpal (CMC) joint arthritis is one of the most common problems addressed by hand surgeons. The gold standard of treatment for thumb CMC joint arthritis is trapeziectomy, ligament reconstruction and tendon interposition. Denervation of the thumb CMC joint is not currently used to treat arthritis in this joint due to the failure of the procedure to yield significant symptomatic relief. The failure of denervation is puzzling, given that past anatomic studies show the radial nerve is the major innervation of the thumb CMC joint with the lateral antebrachial nerve and the median nerve also innervating this joint. Although no anatomic study has ever shown that the ulnar nerve innervates the CMC joint, due to both the failure of denervation and the success of arthroscopic thermal ablation, we suspect that previous anatomic studies may have overlooked innervation of the thumb CMC joint via the ulnar nerve. Methods We dissected 19 formalin-preserved cadaveric hand-to-mid-forearm specimens. The radial, median and ulnar nerves were identified in the proximal forearm and then followed distally. Any branch heading toward the radial side of the hand were followed to see if they innervated the thumb CMC joint. Results Eleven specimens (58%) had superficial radial nerve innervation to the thumb CMC joint. Nine specimens (47%) had median nerve innervation from the motor branch. Nine specimens (47%) had ulnar nerve innervation from the motor branch. Conclusions We believe this is the first study to demonstrate that the ulnar nerve innervates the thumb CMC joint This finding may explain the poor results seen in earlier attempts at denervation of the thumb CMC, but the more favorable results with techniques such as arthroscopy with thermal ablation. PMID:22096446

Surgical ablation of atrial fibrillation during mitral-valve surgery.

PubMed

Gillinov, A Marc; Gelijns, Annetine C; Parides, Michael K; DeRose, Joseph J; Moskowitz, Alan J; Voisine, Pierre; Ailawadi, Gorav; Bouchard, Denis; Smith, Peter K; Mack, Michael J; Acker, Michael A; Mullen, John C; Rose, Eric A; Chang, Helena L; Puskas, John D; Couderc, Jean-Philippe; Gardner, Timothy J; Varghese, Robin; Horvath, Keith A; Bolling, Steven F; Michler, Robert E; Geller, Nancy L; Ascheim, Deborah D; Miller, Marissa A; Bagiella, Emilia; Moquete, Ellen G; Williams, Paula; Taddei-Peters, Wendy C; O'Gara, Patrick T; Blackstone, Eugene H; Argenziano, Michael

2015-04-09

Among patients undergoing mitral-valve surgery, 30 to 50% present with atrial fibrillation, which is associated with reduced survival and increased risk of stroke. Surgical ablation of atrial fibrillation has been widely adopted, but evidence regarding its safety and effectiveness is limited. We randomly assigned 260 patients with persistent or long-standing persistent atrial fibrillation who required mitral-valve surgery to undergo either surgical ablation (ablation group) or no ablation (control group) during the mitral-valve operation. Patients in the ablation group underwent further randomization to pulmonary-vein isolation or a biatrial maze procedure. All patients underwent closure of the left atrial appendage. The primary end point was freedom from atrial fibrillation at both 6 months and 12 months (as assessed by means of 3-day Holter monitoring). More patients in the ablation group than in the control group were free from atrial fibrillation at both 6 and 12 months (63.2% vs. 29.4%, P<0.001). There was no significant difference in the rate of freedom from atrial fibrillation between patients who underwent pulmonary-vein isolation and those who underwent the biatrial maze procedure (61.0% and 66.0%, respectively; P=0.60). One-year mortality was 6.8% in the ablation group and 8.7% in the control group (hazard ratio with ablation, 0.76; 95% confidence interval, 0.32 to 1.84; P=0.55). Ablation was associated with more implantations of a permanent pacemaker than was no ablation (21.5 vs. 8.1 per 100 patient-years, P=0.01). There were no significant between-group differences in major cardiac or cerebrovascular adverse events, overall serious adverse events, or hospital readmissions. The addition of atrial fibrillation ablation to mitral-valve surgery significantly increased the rate of freedom from atrial fibrillation at 1 year among patients with persistent or long-standing persistent atrial fibrillation, but the risk of implantation of a permanent pacemaker was also increased. (Funded by the National Institutes of Health and the Canadian Institutes of Health Research; ClinicalTrials.gov number, NCT00903370.).

Ablating Atrial Fibrillation: Customizing Lesion Sets Guided by Rotor Mapping

PubMed Central

Zaman, Junaid A. B.; Narayan, Sanjiv M.

2015-01-01

Ablation occupies an increasing role in the contemporary management of atrial fibrillation (AF), but results are suboptimal, particularly for persistent AF. While an anatomic approach to ablation is a highly efficacious and safe method to isolate pulmonary vein (PV) triggers, recurrence of AF is not always associated with PV reconnection, and there is compelling evidence that non-PV sites sustain AF after it is triggered. Recent developments in wide-area mapping and signal processing now identify rotors in the vast majority of AF patients that sustain AF and whose elimination improves long-term freedom from AF in multicenter studies. Investigators have now demonstrated rotor and focal sources for AF that show many analogous properties between approaches: they lie in spatially reproducible regions temporally over hours to days, and they are amenable to targeted ablation. This review outlines the rationale and technical developments supporting this mechanistic paradigm for human AF, and discusses how rotor mapping may be implemented for individual patient customization of lesion sets. Mechanistic studies are required to explain why rotor elimination (or other ablation approaches) producing long-term elimination of AF may not always terminate AF acutely, how AF correlates with structural changes on magnetic resonance imaging, and how these findings can be integrated clinically with current ablation strategies to improve patient outcomes. PMID:26306123

MR-guided high-intensity focused ultrasound ablation of breast cancer with a dedicated breast platform.

PubMed

Merckel, Laura G; Bartels, Lambertus W; Köhler, Max O; van den Bongard, H J G Desirée; Deckers, Roel; Mali, Willem P Th M; Binkert, Christoph A; Moonen, Chrit T; Gilhuijs, Kenneth G A; van den Bosch, Maurice A A J

2013-04-01

Optimizing the treatment of breast cancer remains a major topic of interest. In current clinical practice, breast-conserving therapy is the standard of care for patients with localized breast cancer. Technological developments have fueled interest in less invasive breast cancer treatment. Magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) is a completely noninvasive ablation technique. Focused beams of ultrasound are used for ablation of the target lesion without disrupting the skin and subcutaneous tissues in the beam path. MRI is an excellent imaging method for tumor targeting, treatment monitoring, and evaluation of treatment results. The combination of HIFU and MR imaging offers an opportunity for image-guided ablation of breast cancer. Previous studies of MR-HIFU in breast cancer patients reported a limited efficacy, which hampered the clinical translation of this technique. These prior studies were performed without an MR-HIFU system specifically developed for breast cancer treatment. In this article, a novel and dedicated MR-HIFU breast platform is presented. This system has been designed for safe and effective MR-HIFU ablation of breast cancer. Furthermore, both clinical and technical challenges are discussed, which have to be solved before MR-HIFU ablation of breast cancer can be implemented in routine clinical practice.

Ablating Atrial Fibrillation: Customizing Lesion Sets Guided by Rotor Mapping.

PubMed

Zaman, Junaid A B; Narayan, Sanjiv M

2015-01-01

Ablation occupies an increasing role in the contemporary management of atrial fibrillation (AF), but results are suboptimal, particularly for persistent AF. While an anatomic approach to ablation is a highly efficacious and safe method to isolate pulmonary vein (PV) triggers, recurrence of AF is not always associated with PV reconnection, and there is compelling evidence that non-PV sites sustain AF after it is triggered. Recent developments in wide-area mapping and signal processing now identify rotors in the vast majority of AF patients that sustain AF and whose elimination improves long-term freedom from AF in multicenter studies. Investigators have now demonstrated rotor and focal sources for AF that show many analogous properties between approaches: they lie in spatially reproducible regions temporally over hours to days, and they are amenable to targeted ablation. This review outlines the rationale and technical developments supporting this mechanistic paradigm for human AF, and discusses how rotor mapping may be implemented for individual patient customization of lesion sets. Mechanistic studies are required to explain why rotor elimination (or other ablation approaches) producing long-term elimination of AF may not always terminate AF acutely, how AF correlates with structural changes on magnetic resonance imaging, and how these findings can be integrated clinically with current ablation strategies to improve patient outcomes.

History of lasers in otorhinolaryngology-head and neck surgery I: An overview

NASA Astrophysics Data System (ADS)

Shah, Udayan K.; Galera-Ruiz, Hugo

2003-06-01

The history of lasers in otolarygngolgoy-head and neck surgery (ORL) demonstrates the advances seen in the application of laser energies. This paper is the beginning of our review of the five pillars which support the long and mutually-beneficial relationship between laser technologies and ORL: (1) "necessity is the mother of invention" -- organ systems which require innovative approaches for diagnosis and treatment; (2) clinicians who seek and incorporate new technologies; (3) "feedback" effect of technology leading to changes in clinical care which may obviate the need for that technology itself; (4) "right place, right time" -- the close collaboration between corporate, clinical and basic science realms, and (5) financial. These principles provide the context for following the progressive application of laser energy in ORL for ablation, tissue-altering and most recently, sensing.

The IR Evolution in Oncology: Tools, Treatments, and Guidelines.

PubMed

de Baere, Thierry

2017-01-01

Early focus of interventional oncologists was developing tools and imaging guidance, performing "procedures" acting as a skillful technician without knowledge of clinical patient outcomes, beyond post-treatment image findings. Interventional oncologists must deliver "treatments" and not "procedures", and focus on clinically relevant outcomes, provide clinical continuity of care, which means stand at multidisciplinary tumor boards, see patients in consultation before treatment and for follow-up. Interventional oncologists have fought for the same "market" with surgery in a head to head, bloody competition called red ocean strategy in marketing terms, resulting in many aborted trials. Wide adoption of interventional oncology is facing the challenge to build evidence with overall survival as endpoint in randomized trials while the benefits of a treatment on overall survival are diluted by the effects of possible/inevitable subsequent therapies. Because interventional oncology is a disruptive force in medicine achieving same results as others (surgery) using different, less invasive approaches, patients where surgery is irrelevant can be target with a blue ocean strategy (to propose treatment where there is no competition). Recently interventional oncology has been included in the ESMO guidelines for colorectal cancer with oligometastatic disease with both surgical resection, and thermal ablation classified in the same category called "local ablative treatments". Interventional oncologists have to shape the future by publications in oncologic journal, by being active members of oncology scientific societies, and use modern public megaphone (blog, video sharing, …) to disseminate information and let society know that interventional is not a me-too product but a disruptive treatment.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cristescu, Mircea, E-mail: mcristescu@uwhealth.org; Abel, E. Jason, E-mail: abel@urology.wisc.edu; Wells, Shane, E-mail: swells@uwhealth.org

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 complicationsmore » 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.« less

Safety and Efficacy of Uninterrupted Apixaban Therapy Versus Warfarin During Atrial Fibrillation Ablation.

PubMed

Shah, Ruchit R; Pillai, Ajay; Schafer, Pascha; Meggo, David; McElderry, Tom; Plumb, Vance; Yamada, Takumi; Kumar, Vineet; Doppalapudi, Harish; Gunter, Alicia; Pentecost, Emily; Maddox, William R

2017-08-01

Thromboembolic cerebrovascular accident remains a rare but potentially devastating complication of catheter-based atrial fibrillation (AF) ablation. Uninterrupted oral anticoagulant therapy with warfarin has become the standard of care when performing catheter-based AF ablation. Compared with warfarin, apixaban, a factor Xa inhibitor, has been shown to reduce the risk of stroke and major bleeding in nonvalvular AF. With an increase in apixaban use for stroke prophylaxis in patients with AF, there is an increased interest in the safety and efficacy of uninterrupted apixaban therapy during AF ablation. We compared the safety and efficacy of uninterrupted OA therapy with either warfarin or apixaban in all patients who underwent catheter-based AF ablation at the University of Alabama at Birmingham and at Augusta University Medical Center from January 7, 2013, to February 25, 2016. All patients underwent a transesophageal echocardiogram on the day of their ablation to assess for the presence of intracardiac thrombi. All complications were identified and classified as bleeding, thromboembolic events, or other. A total of 627 patients were analyzed as described earlier. There were 310 patients in the warfarin group and 317 patients in the apixaban group. There were 8 complications in the warfarin group and 5 complications in the apixaban group (p = 0.38). There were no thromboembolic complications in either group. In conclusion, the use of apixaban is as safe and effective as warfarin for uninterrupted OA therapy during catheter-based ablation of AF. Copyright © 2017 Elsevier Inc. All rights reserved.

Remote Magnetic versus Manual Navigation for Radiofrequency Ablation of Paroxysmal Atrial Fibrillation: Long-Term, Controlled Data in a Large Cohort.

PubMed

Kataria, Vikas; Berte, Benjamin; Vandekerckhove, Yves; Tavernier, Rene; Duytschaever, Mattias

2017-01-01

Purpose. We aimed to study long-term outcome after pulmonary vein isolation (PVI) guided by remote magnetic navigation (RMN) and provided comparative data to outcome after manual navigation (MAN). Methods. Three hundred thirty-six patients with symptomatic paroxysmal AF underwent PVI by irrigated point-by-point radiofrequency (RF) ablation (RMN, n = 114 versus MAN, n = 222). Patients were followed up with symptom guided rhythm monitoring for a period up to 43 months. The end point of the study was freedom from repeat ablation after a single procedure and without antiarrhythmic drug treatment (ADT). Results. At the end of follow-up (median 26.3 months), freedom from repeat ablation was comparable between RMN and MAN (70.9% versus 69.5%, p = 0.61). At repeat, mean number of reconnected veins was 2.4 ± 1.2 in RMN versus 2.6 ± 1.0 in MAN ( p = 0.08). The majority of repeat procedures occurred during the first year (82.1% in RMN versus 78.5% in MAN; p = 0.74). Conclusion. On the long term (up to 3 years) and in a large cohort of patients with paroxysmal AF, RMN-guided PVI is as effective as MAN guided PVI. In both strategies the majority of repeat procedures occurred during the first year after index procedure.

Remote Magnetic versus Manual Navigation for Radiofrequency Ablation of Paroxysmal Atrial Fibrillation: Long-Term, Controlled Data in a Large Cohort

PubMed Central

Berte, Benjamin; Vandekerckhove, Yves; Tavernier, Rene

2017-01-01

Purpose. We aimed to study long-term outcome after pulmonary vein isolation (PVI) guided by remote magnetic navigation (RMN) and provided comparative data to outcome after manual navigation (MAN). Methods. Three hundred thirty-six patients with symptomatic paroxysmal AF underwent PVI by irrigated point-by-point radiofrequency (RF) ablation (RMN, n = 114 versus MAN, n = 222). Patients were followed up with symptom guided rhythm monitoring for a period up to 43 months. The end point of the study was freedom from repeat ablation after a single procedure and without antiarrhythmic drug treatment (ADT). Results. At the end of follow-up (median 26.3 months), freedom from repeat ablation was comparable between RMN and MAN (70.9% versus 69.5%, p = 0.61). At repeat, mean number of reconnected veins was 2.4 ± 1.2 in RMN versus 2.6 ± 1.0 in MAN (p = 0.08). The majority of repeat procedures occurred during the first year (82.1% in RMN versus 78.5% in MAN; p = 0.74). Conclusion. On the long term (up to 3 years) and in a large cohort of patients with paroxysmal AF, RMN-guided PVI is as effective as MAN guided PVI. In both strategies the majority of repeat procedures occurred during the first year after index procedure. PMID:28386560

Microwave ablation for thyroid nodules: a new string to the bow for percutaneous treatments?

PubMed Central

Morelli, Francesco; Sacrini, Andrea; Pompili, Giovanni; Borelli, Anna; Panella, Silvia; Masu, Annamaria; De Pasquale, Loredana; Giacchero, Roberta

2016-01-01

Background Thyroid nodules are a fairly common finding in general population and, even if most of them are benign, a treatment can be however necessary. In the last years, non surgical minimally invasive techniques have been developed to treat this pathology, starting from percutaneous ethanol injection (PEI), to laser ablation (LA), radiofrequency ablation (RFA) and, most recently, microwave ablation (MWA). Methods We reviewed all medical literature searching in pubmed.gov the terms “microwave” & “thyroid”. We found three original studies concerning MWA treatment, for a total of 263 patients (mean age 51.0 years; range, 15–80 years; male to female ratio 2.55) and 522 nodules. Results A total of 522 nodules (338 solid, 22 cystic, 162 mixed) in 263 patients were treated. Studies have shown a mean reduction in volume of thyroid nodules ranging from 45.9% to 65%. No study reported a significant and definitive change in laboratory parameters, except for one case (Heck et al.). No studies have reported major complications after procedure. Conclusions MWA is a new, promising technique among the minimally invasive treatments of thyroid nodules. Actually, the larger diameter of MW antenna seems to be the major limiting factor in the use of this technique. More studies are necessary to evaluate feasibility, safety and efficacy of the procedure. PMID:28149799

Radiofrequency ablation of the pancreas: protective effect of local cooling techniques.

PubMed

Geranios, Angelos; Pikoulis, Emmanouil; Papalois, Apostolos; Kontos, Michael; Agrogiannis, George; Petrou, Athanasios; Pavlakis, Emmanuel; Felekouras, Evangelos

2015-05-01

Pancreatic carcinoma is one of the commonest malignant diseases today and the majority of patients are suitable for palliative treatment only. Radiofrequency ablation (RFA) has been used extensively for the treatment of solid organ tumors but little is known on the efficacy and safety of pancreatic ablation. To further investigate the safety of pancreatic RFA, 18 pigs had RFA of the pancreas, close to superior mesenteric vein and duodenum. Group A (nine animals) was protected with peripancreatic cool perfusion and Group B (nine animals) with portal vein (PV) intravenous injection of cool saline. Biochemical and histological evidence suggested lateral thermal injury of the duodenal wall and superior mesenteric vein and acute pancreatitis in most animals. However, clinically and at autopsy, Group B animals fared much better. PV thrombosis, hepatic abscess, duodenal perforation, ascites, and extensive pancreatic necrosis were observed in Group A but not in Group B. The present study suggests that PV cool saline perfusion can prevent major complications caused by pancreatic RFA and may be used in combination with other protective techniques in the clinical setting to reduce RFA-associated morbidity.

Safety and feasibility of leadless pacemaker in patients undergoing atrioventricular node ablation for atrial fibrillation.

PubMed

Yarlagadda, Bharath; Turagam, Mohit K; Dar, Tawseef; Jangam, Pragna; Veerapaneni, Vaishnavi; Atkins, Donita; Bommana, Sudharani; Friedman, Paul; Deshmukh, Abhishek J; Doshi, Rahul; Reddy, Vivek Y; Dukkipati, Srinivas R; Natale, Andrea; Lakkireddy, Dhanunjaya

2018-03-01

Atrioventricular node (AVN) ablation and permanent pacing is an established strategy for rate control in the management of symptomatic atrial fibrillation (AF). Leadless pacemakers (LPs) can overcome some of the short-term and long-term limitations of conventional transvenous pacemakers (CTPs). The purpose of this study was to compare the feasibility and safety of LP with those of single-chamber CTP in patients with AF undergoing AVN ablation. We conducted a multicenter observational study of patients undergoing AVN ablation and pacemaker implantation (LP vs single-chamber CTP) between February 2014 and November 2016. The primary efficacy end points were acceptable sensing (R wave ≥5.0 mV) and pacing thresholds (≤2.0 V at 0.4 ms) at follow-up. Safety end points included device-related major and minor (early ≤1 month, late >1 month) adverse events. A total of 127 patients with LP (n = 60) and CTP (n = 67) were studied. The median follow-up was 12 months (interquartile range 12-18 months). Ninety-five percent of the LP group and 97% of the CTP group met the primary efficacy end point at follow-up (57 of 60 vs 65 of 67; P = .66). There was 1 major adverse event (loss of pacing and sensing) in the LP group and 2 (lead dislodgement) in the CTP group (1 of 60 vs 2 of 67; P = 1.00). There were 6 minor adverse events (5 early and 1 late) in the LP group and 3 (early) in the CTP group (6 of 60 vs 3 of 67; P = .30). Our results demonstrate the feasibility and safety of LP compared with CTP in patients undergoing AVN ablation for AF. Copyright © 2018 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Magnetic versus manual catheter navigation for mapping and ablation of right ventricular outflow tract ventricular arrhythmias: a randomized controlled study.

PubMed

Zhang, Fengxiang; Yang, Bing; Chen, Hongwu; Ju, Weizhu; Kojodjojo, Pipin; Cao, Kejiang; Chen, Minglong

2013-08-01

No randomized controlled study has prospectively compared the performance and clinical outcomes of remote magnetic control (RMC) vs manual catheter control (MCC) during ablation of right ventricular outflow tract (RVOT) ventricular premature complexes (VPC) or ventricular tachycardia (VT). The purpose of this study was to prospectively evaluate the efficacy and safety of using either RMC vs MCC for mapping and ablation of RVOT VPC/VT. Thirty consecutive patients with idiopathic RVOT VPC/VT were referred for catheter ablation and randomized into either the RMC or MCC group. A noncontact mapping system was deployed in the RVOT to identify origins of VPC/VT. Conventional activation and pace-mapping was performed to guide ablation. If ablation performed using 1 mode of catheter control was acutely unsuccessful, the patient crossed over to the other group. The primary endpoints were patients' and physicians' fluoroscopic exposure and times. Mean procedural times were similar between RMC and MCC groups. The fluoroscopic exposure and times for both patients and physicians were much lower in the RMC group than in the MCC group. Ablation was acutely successful in 14 of 15 patients in the MCC group and 10 of 15 in the RMC group. Following crossover, acute success was achieved in all patients. No major complications occurred in either group. During 22 months of follow-up, RVOT VPC recurred in 2 RMC patients. RMC navigation significantly reduces patients' and physicians' fluoroscopic times by 50.5% and 68.6%, respectively, when used in conjunction with a noncontact mapping system to guide ablation of RVOT VPC/VT. Copyright © 2013 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

In vivo evaluation of virtual electrode mapping and ablation utilizing a direct endocardial visualization ablation catheter.

PubMed

Chik, William W B; Barry, M A; Malchano, Zach; Wylie, Bryan; Pouliopoulos, Jim; Huang, Kaimin; Lu, Juntang; Thavapalachandran, Sujitha; Robinson, David; Saadat, Vahid; Thomas, Stuart P; Ross, David L; Kovoor, Pramesh; Thiagalingam, Aravinda

2012-01-01

Radiofrequency (RF) ablation utilizing direct endocardial visualization (DEV) requires a "virtual electrode" to deliver RF energy while preserving visualization. This study aimed to: (1) examine the virtual electrode RF ablation efficacy; (2) determine the optimal power and duration settings; and (3) evaluate the utility of virtual electrode unipolar electrograms. The DEV catheter lesions were compared to lesions formed using a 3.5 mm open irrigated tip catheter within the right atria of 12 sheep. Generator power settings for DEV were titrated from 12W, 14W and 16W for 20, 30 and 40 seconds duration with 25 mL/min saline irrigation. Standard irrigated tip catheter settings of 30W, 50°C for 30 seconds and 30 mL/min were used. The DEV lesions were significantly greater in surface area and both major and minor axes compared to irrigated tip lesions (surface area 19.43 ± 9.09 vs 10.88 ± 4.72 mm, P<0.01) with no difference in transmurality (93/94 vs 46/47) or depth (1.86 ± 0.75 vs 1.85 ± 0.57 mm). Absolute electrogram amplitude reduction was greater for DEV lesions (1.89 ± 1.31 vs 1.49 ± 0.78 mV, P = 0.04), but no difference in percentage reduction. Pre-ablation pacing thresholds were not different between DEV (0.79 ± 0.36 mA) and irrigated tip (0.73 ± 0.25 mA) lesions. There were no complications noted during ablation with either catheter. Virtual electrode ablation consistently created wider lesions at lower power compared to irrigated tip ablation. Virtual electrode electrograms showed a comparable pacing and sensing efficacy in detecting local myocardial electrophysiological changes. © 2011 Wiley Periodicals, Inc.

Design Considerations For A Clinical XeC1 Excimer Laser Angioplasty System

NASA Astrophysics Data System (ADS)

Laudenslager, James B.; Goldenberg, Tsvi; Naghieh, Harry R.; Pham, Andrew A.; Narciso, Hugh L.; Tranis, Art; Pacala, Thomas J.

1989-09-01

Laser ablation and removal of intravascular plaque has long been a goal of physicians and physicists as an alternative treatment for coronary and peripheral artery disease. Early application of cw free light beam visible and infrared lasers such as argon ion or Nd:YAG lasers for this application were plagued by thermal side effects of the ablation process. Specifically, imprecise control of the boundary tissue injury produced by the deep penetration depth of the laser beam gave rise to early reclosure of the vessel due to the thermal nature of the ablation process. Pulsed ultraviolet laser free beam ablation of atherosclerotic plaque, however, does not produce thermal effects, cuts tissue precisely leaving a smooth wall and can ablate hard calcific lesions. We have chosen to develop a XeC1 excimer laser-fiberoptic delivery system for the clinical application of laser angioplasty based on achieving the desired therapeutic results for a laser revascularization procedure. Four major engineering design issues must be considered in order to produce a successful clinical laser angioplasty product. These engineering issues are: 1) Functional clinical engineering, 2) Regulatory design issues, 3) Hospital facility and user requirements, and 4) Economic issues for the manufacturer, the hospital and the patient.

Cluster headache syndrome. Ways to abort or ward off attacks.

PubMed

Marks, D R; Rapoport, A M

1992-02-15

Cluster headache is a syndrome of severe head and facial pain accompanied by autonomic abnormalities. Men are affected more frequently than women. Headaches occur daily during periods of susceptibility, which may be followed by periods of remission. The etiology of cluster headache is uncertain. Recent work suggests that hypothalamic dysfunction and/or oxyhemoglobin desaturation may be involved in its pathogenesis. Effective medical regimens are available for aborting acute attacks and for preventing attacks. Surgical ablation of the trigeminal ganglion has been effective in some patients when conventional medical therapy has failed.

Influence of electric field on the behavior of Si nanoparticles generated by laser ablation

NASA Astrophysics Data System (ADS)

Muramoto, Junichi; Sakamoto, Ippei; Nakata, Yoshiki; Okada, Tatsuo; Maeda, Mitsuo

1999-08-01

The influence of an electric field on particle behavior was investigated to control the transport of Si nanoparticles in a laser ablation plume by an ultraviolet Rayleigh scattering (UV-RS) technique. The majority of the nanoparticles, which could be observed by the UV-RS technique, were transported to the negatively biased electrode, indicating that they were positively charged. The deposition efficiency of nanoparticles onto a substrate was also improved by applying an electric field.

Control of spatial orientation of the angular vestibuloocular reflex by the nodulus and uvula.

PubMed

Wearne, S; Raphan, T; Cohen, B

1998-05-01

Spatial orientation of the angular vestibuloocular reflex (aVOR) was studied in rhesus monkeys after complete and partial ablation of the nodulus and ventral uvula. Horizontal, vertical, and torsional components of slow phases of nystagmus were analyzed to determine the axes of eye rotation, the time constants (Tcs) of velocity storage, and its orientation vectors. The gravito-inertial acceleration vector (GIA) was tilted relative to the head during optokinetic afternystagmus (OKAN), centrifugation, and reorientation of the head during postrotatory nystagmus. When the GIA was tilted relative to the head in normal animals, horizontal Tcs decreased, vertical and/or roll time constants (Tc(vert/roll)) lengthened according to the orientation of the GIA, and vertical and/or roll eye velocity components appeared (cross-coupling). This shifted the axis of eye rotation toward alignment with the tilted GIA. Horizontal and vertical/roll Tcs varied inversely, with T(chor) being longest and T(cvert/roll) shortest when monkeys were upright, and the reverse when stimuli were around the vertical or roll axes. Vertical or roll Tcs were longest when the axes of eye rotation were aligned with the spatial vertical, respectively. After complete nodulo-uvulectomy, T(chor) became longer, and periodic alternating nystagmus (PAN) developed in darkness. T(chor) could not be shortened in any of paradigms tested. In addition, yaw-to-vertical/roll cross-coupling was lost, and the axes of eye rotation remained fixed during nystagmus, regardless of the tilt of the GIA with respect to the head. After central portions of the nodulus and uvula were ablated, leaving lateral portions of the nodulus intact, yaw-to-vertical/roll cross-coupling and control of Tc(vert/roll) was lost or greatly reduced. However, control of Tchor was maintained, and T(chor) continued to vary as a function of the tilted GIA. Despite this, the eye velocity vector remained aligned with the head during yaw axis stimulation after partial nodulo-uvulectomy, regardless of GIA orientation to the head. The data were related to a three-dimensional model of the aVOR, which simulated the experimental results. The model provides a basis for understanding how the nodulus and uvula control processing within the vestibular nuclei responsible for spatial orientation of the aVOR. We conclude that the three-dimensional dynamics of the velocity storage system are determined in the nodulus and ventral uvula. We propose that the horizontal and vertical/roll Tcs are separately controlled in the nodulus and uvula with the dynamic characteristics of vertical/roll components modulated in central portions and the horizontal components laterally, presumably in a semicircular canal-based coordinate frame.

Formation of Plasma Around a Small Meteoroid: Simulation and Theory

NASA Astrophysics Data System (ADS)

Sugar, G.; Oppenheim, M. M.; Dimant, Y. S.; Close, S.

2018-05-01

High-power large-aperture radars detect meteors by reflecting radio waves off dense plasma that surrounds a hypersonic meteoroid as it ablates in the Earth's atmosphere. If the plasma density profile around the meteoroid is known, the plasma's radar cross section can be used to estimate meteoroid properties such as mass, density, and composition. This paper presents head echo plasma density distributions obtained via two numerical simulations of a small ablating meteoroid and compares the results to an analytical solution found in Dimant and Oppenheim (2017a, https://doi.org/10.1002/2017JA023960, 2017b, https://doi.org/10.1002/2017JA023963). The first simulation allows ablated meteoroid particles to experience only a single collision to match an assumption in the analytical solution, while the second is a more realistic simulation by allowing multiple collisions. The simulation and analytical results exhibit similar plasma density distributions. At distances much less than λT, the average distance an ablated particle travels from the meteoroid before a collision with an atmospheric particle, the plasma density falls off as 1/R, where R is the distance from the meteoroid center. At distances substantially greater than λT, the plasma density profile has an angular dependence, falling off as 1/R2 directly behind the meteoroid, 1/R3 in a plane perpendicular to the meteoroid's path that contains the meteoroid center, and exp[-1.5(R/λT2/3)]/R in front of the meteoroid. When used for calculating meteoroid masses, this new plasma density model can give masses that are orders of magnitude different than masses calculated from a spherically symmetric Gaussian distribution, which has been used to calculate masses in the past.

Six-month follow-up of isthmus-dependent right atrial flutter ablation using a remote magnetic catheter navigation system: a case-control study.

PubMed

Huo, Yan; Hindricks, Gerhard; Piorkowski, Christopher; Bollmann, Andreas; Wetzel, Ulrike; Sommer, Phillip; Gaspar, Thomas; Kottkamp, Hans; Arya, Arash

2010-06-01

The objective of this study was to compare results between the magnetic navigation system (MNS) and conventional catheter ablation of cavo-tricuspid isthmus (CTI)-dependent right atrial flutter (AFL) in a case control study. A remote MNS has been used for ablation of various arrhythmias including CTI-dependent AFL but comparative results between MNS and conventional ablation are not available. Between May and September 2007, a total of 51 consecutive patients (45 men, mean age 65.4 +/- 9.4 years) had undergone catheter ablation for CTI-dependent AFL. The catheter ablation (70 degrees C, 70 W, 90 s) was performed with either an 8-mm-tip magnetic catheter using MNS (case group, n = 26, 23 men, mean age 64.6 +/- 9.6 y) or a conventional 8-mm catheter (case group, n = 25, 22 men, mean age 65.4 +/- 9.1 y). Acute procedural success was defined as complete bidirectional isthmus block and success at six months was defined as absence of AFL during the six months follow-up. With respect to baseline characteristics there were no differences between the two groups. The procedure time in MNS and conventional group was [median (range)] 53 (30-130) min and 45 (30-100) min, respectively (P = 0.12). Acute success was achieved by MNS and conventional ablation in 25/26 (96.2%) and 25/25 (100%) of patients, respectively (P = 0.53). During the six months of follow-up 4 patients, 2 in each group, experienced recurrence (P = 0.90). No major complication occurred during the procedure. Charring on the catheter tip occurred in 5 patients (19.2%) in MNS and none of the patients in the control group (P <0.05). This case-control study demonstrated the acute and mid-term efficacy and safety of catheter ablation by MNS for CTI-dependent AFL, similar to rates achieved by conventional radiofrequency catheter ablation.

Liver cancer: increased microwave delivery to ablation zone with cooled-shaft antenna--experimental and clinical studies.

PubMed

Kuang, Ming; Lu, Ming D; Xie, Xiao Y; Xu, Hui X; Mo, Li Q; Liu, Guang J; Xu, Zuo F; Zheng, Yan L; Liang, Jin Y

2007-03-01

To prospectively investigate whether the ablation zone induced with microwaves could be increased by delivering greater energy with a cooled-shaft antenna. All studies were animal care and ethics committee approved. Written informed consent was obtained from all patients. Microwave ablation was performed by using a cooled-shaft antenna in 48 ex vivo and 12 in vivo experiments with porcine livers. The coagulation diameters achieved in different microwave ablation parameter groups (60-90 W for 5-25 minutes) were compared. Ninety patients (78 men, 12 women; mean age, 53 years; age range, 20-82 years) with 133 0.8-8.0-cm (mean, 2.7 cm +/- 1.5 [standard deviation]) primary or metastatic liver cancers were treated with the same microwave ablation technique. Complete ablation (CA) and local tumor progression (LTP) rates were determined. Generalized estimating equations were used to compare differences in tumor size, ablation zone diameter, and CA and LTP rates between different patient subgroups. In the ex vivo livers, in vivo livers, and liver cancers, one application of microwave energy with 80 W for 25 minutes produced mean coagulation diameters of 5.6 x 7.4 cm, 3.5 x 5.9 cm, and 3.6 x 5.0 cm, respectively. Skin burn was not observed. CA rates in small (

[Radiofrequency ablation as a palliative therapy option in ENT tumors: in vivo and in vitro testing].

PubMed

Bucher, S; Hornung, J; Bonkowsky, V; Iro, H; Zenk, J

2010-04-01

High frequency thermotherapy (HFTT) is an established palliative therapy for hepatic malignancies. An in vivo and in vitro trial examined the preconditions for the application of HFTT with liquid-cooled wet electrodes for minimally invasive palliation of head and neck tumors. HFTT was applied with needle electrodes, cooled with isotonic saline solution, and a high-frequency generator (Elektrotom HiTT 106, Berchtold, Tuttlingen) to porcine tongue and narcotized, juvenile domestic pigs to the tongue and neck, and monitored in realtime by B-mode ultrasound. The direction of spread of the hyperthermic zone is well observed using ultrasound. Determining the direction of spread is not possible with cooled-tip electrode needles. Severe complications were not observed during the application. RFA with liquid-cooled needle applicators is not safely applicable for the therapy of head and neck tumors.

[Magnetic navigation for ablation of cardiac arrhythmias].

PubMed

Chen, Jian; Hoff, Per Ivar; Solheim, Eivind; Schuster, Peter; Off, Morten Kristian; Ohm, Ole-Jørgen

2010-08-12

The first use of magnetic navigation for radiofrequency ablation of supraventricular tachycardias, was published in 2004. Subsequently, the method has been used for treatment of most types of tachyarrhythmias. This paper provides an overview of the method, with special emphasis on usefulness of a new remote-controlled magnetic navigation system. The paper is based on our own scientific experience and literature identified through a non-systematic search in PubMed. The magnetic navigation system consists of two external electromagnets (to be placed on opposite sides of the patient), which guide an ablation catheter (with a small magnet at the tip of the catheter) to the target area in the heart. The accuracy of this procedure is higher than that with manual navigation. Personnel can be quickly trained to use remote magnetic navigation, but the procedure itself is time-consuming, particularly for patients with atrial fibrillation. The major advantage is a considerably lower radiation burden to both patient and operator, in some studies more than 50 %, and a corresponding reduction in physical strain on the operator. The incidence of procedure-related complications seems to be lower than that observed with use of manually operated ablation catheters. Work is ongoing to improve magnetic ablation catheters and methods that can simplify mapping procedures and improve efficacy of arrhythmia ablation. The basic cost for installing a complete magnetic navigation laboratory may be three times that of a conventional electrophysiological laboratory. The new magnetic navigation system has proved to be applicable during ablation for a variety of tachyarrhythmias, but is still under development.

Microwave ablation of hepatocellular carcinoma

PubMed Central

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

2015-01-01

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

Microwave liver ablation: influence of hepatic vein size on heat-sink effect in a porcine model.

PubMed

Yu, Nam C; Raman, Steven S; Kim, Young Jun; Lassman, Charles; Chang, Xinlian; Lu, David S K

2008-07-01

To determine influence of hepatic vein size on perfusion-mediated attenuation in adjacent microwave thermal ablation. With approval of the institutional animal research committee, seven Yorkshire pigs underwent percutaneous (n = 2) or open (n = 5) microwave liver ablation under general anesthesia. In each, multiple ultrasound-guided, nonoverlapping thermal lesions were created within 1 cm of hepatic veins in a 5-10-minute ablation at 45 W. After euthanasia, the liver was harvested and sectioned at 0.5-cm intervals and the degree of perivascular coagulation attenuation was graded on histopathologic analysis. Correlation between venous size (small, < or =3 mm; medium, 3-6 mm; and large, >6 mm) and attenuation grade was performed with use of the Spearman rank test. In 63 of 103 sections (61%)--29 of 37 (78%) small, 27 of 48 (56%) medium, and seven of 18 (39%) large veins--the thermal injury extended to the vein wall around the entire circumference of the coagulation front without distortion of the ablation margin. In 40 of 103 sections (38.9%), varying degrees of concave distortion of perivenous ablation margins were noted, with significant correlation between vein size and heat-sink extent (P < .01). However, thermal injury extended to the vascular wall in all sections without complete circumferential sparing of liver tissue. Around two thrombosed veins, thermal lesions encased the vessels, producing paradoxically convex ablation margins. Although the heat-sink effect was significantly dependent on hepatic vein size, the majority of pathologic sections exhibited no or minimal effect. Further study is required to assess clinical implications.

Discrimination of benign and neoplastic mucosa with a high-resolution microendoscope (HRME) in head and neck cancer.

PubMed

Vila, Peter M; Park, Chan W; Pierce, Mark C; Goldstein, Gregg H; Levy, Lauren; Gurudutt, Vivek V; Polydorides, Alexandros D; Godbold, James H; Teng, Marita S; Genden, Eric M; Miles, Brett A; Anandasabapathy, Sharmila; Gillenwater, Ann M; Richards-Kortum, Rebecca; Sikora, Andrew G

2012-10-01

The efficacy of ablative surgery for head and neck squamous cell carcinoma (HNSCC) depends critically on obtaining negative margins. Although intraoperative "frozen section" analysis of margins is a valuable adjunct, it is expensive, time-consuming, and highly dependent on pathologist expertise. Optical imaging has potential to improve the accuracy of margins by identifying cancerous tissue in real time. Our goal was to determine the accuracy and inter-rater reliability of head and neck cancer specialists using high-resolution microendoscopic (HRME) images to discriminate between cancerous and benign mucosa. Thirty-eight patients diagnosed with head and neck squamous cell carcinoma (HNSCC) were enrolled in this single-center study. HRME was used to image each specimen after application of proflavine, with concurrent standard histopathologic analysis. Images were evaluated for quality control, and a training set containing representative images of benign and neoplastic tissue was assembled. After viewing training images, seven head and neck cancer specialists with no previous HRME experience reviewed 36 test images and were asked to classify each. The mean accuracy of all reviewers in correctly diagnosing neoplastic mucosa was 97% (95% confidence interval (CI), 94-99%). The mean sensitivity and specificity were 98% (97-100%) and 92% (87-98%), respectively. The Fleiss kappa statistic for inter-rater reliability was 0.84 (0.77-0.91). Medical professionals can be quickly trained to use HRME to discriminate between benign and neoplastic mucosa in the head and neck. With further development, the HRME shows promise as a method of real-time margin determination at the point of care.

45 CFR 1309.52 - Procurement procedures.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., DEPARTMENT OF HEALTH AND HUMAN SERVICES THE ADMINISTRATION FOR CHILDREN, YOUTH AND FAMILIES, HEAD START PROGRAM HEAD START FACILITIES PURCHASE, MAJOR RENOVATION AND CONSTRUCTION Construction and Major Renovation § 1309.52 Procurement procedures. (a) All facility construction and major renovation transactions...

45 CFR 1309.52 - Procurement procedures.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., DEPARTMENT OF HEALTH AND HUMAN SERVICES THE ADMINISTRATION FOR CHILDREN, YOUTH AND FAMILIES, HEAD START PROGRAM HEAD START FACILITIES PURCHASE, MAJOR RENOVATION AND CONSTRUCTION Construction and Major Renovation § 1309.52 Procurement procedures. (a) All facility construction and major renovation transactions...

Comparison of switching bipolar ablation with multiple cooled wet electrodes and switching monopolar ablation with separable clustered electrode in treatment of small hepatocellular carcinoma: A randomized controlled trial

PubMed Central

Chang, Won; Lee, Dong Ho; Yoon, Jeong Hee; Kim, Yoon Jun; Yoon, Jung Hwan; Han, Joon Koo

2018-01-01

Objective A randomized controlled trial was conducted to prospectively compare the therapeutic effectiveness of switching bipolar (SB) radiofrequency ablation (RFA) using cooled-wet electrodes and switching monopolar (SM) RFA using separable clustered (SC) electrodes in patients with hepatocellular carcinomas (HCCs). Materials and methods This prospective study was approved by our Institutional Review Board. Between April 2014 and January 2015, sixty-nine patients with 74 HCCs were randomly treated with RFA using either internally cooled-wet (ICW) electrodes in SB mode (SB-RFA, n = 36) or SC electrodes in SM mode (SM-RFA, n = 38). Technical parameters including the number of ablations, ablation time, volume, energy delivery, and complications were evaluated. Thereafter, 1-year and 2-year local tumor progression (LTP) free survival rates were compared between the two groups using the Kaplan-Meier method. Results In the SB-RFA group, less number of ablations were required (1.72±0.70 vs. 2.31±1.37, P = 0.039), the ablation time was shorter (10.9±3.9 vs.14.3±5.0 min, p = 0.004), and energy delivery was smaller (13.1±6.3 vs.23.4±12.8 kcal, p<0.001) compared to SM-RFA. Ablation volume was not significantly different between SB-RFA and SM-RFA groups (61.8±24.3 vs.54.9±23.7 cm3, p = 0.229). Technical failure occurred in one patient in the SM-RFA group, and major complications occurred in one patient in each group. The 1-year and 2-year LTP free survival rates were 93.9% and 84.3% in the SB-RFA group and 94.4% and 88.4% in the SM-RFA group (p = 0.687). Conclusion Both SB-RFA using ICW electrodes and SM-RFA using SC electrodes provided comparable LTP free survival rates although SB-RFA required less ablations and shorter ablation time. PMID:29420589

Catheter Ablation of Ventricular Tachycardia

MedlinePlus

... Bridging Disciplines Circulation at Major Meetings Special Themed Issues Global Impact of the 2017 ACC/AHA Hypertension Guidelines Circulation Supplements Cardiovascular Case Series ECG Challenge Hospitals of History Brigham and ...

Radar Detectability Studies of Slow and Small Zodiacal Dust Cloud Particles. III. The Role of Sodium and the Head Echo Size on the Probability of Detection

NASA Astrophysics Data System (ADS)

Janches, D.; Swarnalingam, N.; Carrillo-Sanchez, J. D.; Gomez-Martin, J. C.; Marshall, R.; Nesvorný, D.; Plane, J. M. C.; Feng, W.; Pokorný, P.

2017-07-01

We present a path forward on a long-standing issue concerning the flux of small and slow meteoroids, which are believed to be the dominant portion of the incoming meteoric mass flux into the Earth’s atmosphere. Such a flux, which is predicted by dynamical dust models of the Zodiacal Cloud, is not evident in ground-based radar observations. For decades this was attributed to the fact that the radars used for meteor observations lack the sensitivity to detect this population, due to the small amount of ionization produced by slow-velocity meteors. Such a hypothesis has been challenged by the introduction of meteor head echo (HE) observations with High Power and Large Aperture radars, in particular the Arecibo 430 MHz radar. Janches et al. developed a probabilistic approach to estimate the detectability of meteors by these radars and initially showed that, with the current knowledge of ablation and ionization, such particles should dominate the detected rates by one to two orders of magnitude compared to the actual observations. In this paper, we include results in our model from recently published laboratory measurements, which showed that (1) the ablation of Na is less intense covering a wider altitude range; and (2) the ionization probability, {β }{ip}, for Na atoms in the air is up to two orders of magnitude smaller for low speeds than originally believed. By applying these results and using a somewhat smaller size of the HE radar target we offer a solution that reconciles these observations with model predictions.

Radar detectability studies of slow and small Zodiacal Dust Cloud Particles: I. The case of Arecibo 430 MHz meteor head echo observations

PubMed Central

Janches, D.; Plane, J.M.C.; Nesvorný, D.; Feng, W.; Vokrouhlický, D.; Nicolls, M.J.

2016-01-01

Recent model development of the Zodiacal Dust Cloud (ZDC) model (Nesvorný et al. 2010, 2011b) argue that the incoming flux of meteoric material into the Earth’s upper atmosphere is mostly undetected by radars because they cannot detect small extraterrestrial particles entering the atmosphere at low velocities due to the relatively small production of electrons. In this paper we present a new methodology utilizing meteor head echo radar observations that aims to constrain the ZDC physical model by ground-based measurements. In particular, for this work, we focus on Arecibo 430 MHz observations since this is the most sensitive radar utilized for this type of observations to date. For this, we integrate and employ existing comprehensive models of meteoroid ablation, ionization and radar detection to enable accurate interpretation of radar observations and show that reasonable agreement in the hourly rates is found between model predictions and Arecibo observations when: 1) we invoke the lower limit of the model predicted flux (~16 t/d) and 2) we estimate the ionization probability of ablating metal atoms using laboratory measurements of the ionization cross sections of high speed metal atom beams, resulting in values up to two orders of magnitude lower than the extensively utilized figure reported by Jones (1997) for low speeds meteors. However, even at this lower limit the model over predicts the slow portion of the Arecibo radial velocity distributions by a factor of 3, suggesting the model requires some revision. PMID:27642186

Radar Detectability Studies of Slow and Small Zodiacal Dust Cloud Particles: I. The Case of Arecibo 430 MHz Meteor Head Echo Observations

NASA Technical Reports Server (NTRS)

Janches, D.; Plane, J. M. C.; Nesvorny, D.; Feng, W.; Vokrouhlicky, D.; Nicolls, M. J.

2014-01-01

Recent model development of the Zodiacal Dust Cloud (ZDC) model (Nesvorny et al. 2010, 2011b) argue that the incoming flux of meteoric material into the Earth's upper atmosphere is mostly undetected by radars because they cannot detect small extraterrestrial particles entering the atmosphere at low velocities due to the relatively small production of electrons. In this paper we present a new methodology utilizing meteor head echo radar observations that aims to constrain the ZDC physical model by ground-based measurements. In particular, for this work, we focus on Arecibo 430 MHz observations since this is the most sensitive radar utilized for this type of observations to date. For this, we integrate and employ existing comprehensive models of meteoroid ablation, ionization and radar detection to enable accurate interpretation of radar observations and show that reasonable agreement in the hourly rates is found between model predictions and Arecibo observations when: 1) we invoke the lower limit of the model predicted flux (approximately 16 t/d) and 2) we estimate the ionization probability of ablating metal atoms using laboratory measurements of the ionization cross sections of high speed metal atom beams, resulting in values up to two orders of magnitude lower than the extensively utilized figure reported by Jones (1997) for low speeds meteors. However, even at this lower limit the model over predicts the slow portion of the Arecibo radial velocity distributions by a factor of 3, suggesting the model requires some revision.

Radar Detectability Studies of Slow and Small Zodiacal Dust Cloud Particles. III. The Role of Sodium and the Head Echo Size on the Probability of Detection

NASA Technical Reports Server (NTRS)

Janches, D.; Swarnalingam, N.; Carrillo-Sanchez, J. D.; Gomez-Martin, J. C.; Marshall, R.; Nesvorny, D.; Plane, J. M. C.; Feng, W.; Pokorny, P.

2017-01-01

We present a path forward on a long-standing issue concerning the flux of small and slow meteoroids, which are believed to be the dominant portion of the incoming meteoric mass flux into the Earth's atmosphere. Such a flux, which is predicted by dynamical dust models of the Zodiacal Cloud, is not evident in ground-based radar observations. For decades this was attributed to the fact that the radars used for meteor observations lack the sensitivity to detect this population, due to the small amount of ionization produced by slow-velocity meteors. Such a hypothesis has been challenged by the introduction of meteor head echo (HE) observations with High Power and Large Aperture radars, in particular the Arecibo 430 MHz radar. Janches et al. developed a probabilistic approach to estimate the detectability of meteors by these radars and initially showed that, with the current knowledge of ablation and ionization, such particles should dominate the detected rates by one to two orders of magnitude compared to the actual observations. In this paper, we include results in our model from recently published laboratory measurements, which showed that (1) the ablation of Na is less intense covering a wider altitude range; and (2) the ionization probability, Beta ip, for Na atoms in the air is up to two orders of magnitude smaller for low speeds than originally believed. By applying these results and using a somewhat smaller size of the HE radar target we offer a solution that reconciles these observations with model predictions.

The IR Evolution in Oncology: Tools, Treatments, and Guidelines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baere, Thierry de, E-mail: thierry.debaere@gustaveroussy.fr

Early focus of interventional oncologists was developing tools and imaging guidance, performing “procedures” acting as a skillful technician without knowledge of clinical patient outcomes, beyond post-treatment image findings. Interventional oncologists must deliver “treatments” and not “procedures”, and focus on clinically relevant outcomes, provide clinical continuity of care, which means stand at multidisciplinary tumor boards, see patients in consultation before treatment and for follow-up. Interventional oncologists have fought for the same “market” with surgery in a head to head, bloody competition called red ocean strategy in marketing terms, resulting in many aborted trials. Wide adoption of interventional oncology is facing themore » challenge to build evidence with overall survival as endpoint in randomized trials while the benefits of a treatment on overall survival are diluted by the effects of possible/inevitable subsequent therapies. Because interventional oncology is a disruptive force in medicine achieving same results as others (surgery) using different, less invasive approaches, patients where surgery is irrelevant can be target with a blue ocean strategy (to propose treatment where there is no competition). Recently interventional oncology has been included in the ESMO guidelines for colorectal cancer with oligometastatic disease with both surgical resection, and thermal ablation classified in the same category called “local ablative treatments”. Interventional oncologists have to shape the future by publications in oncologic journal, by being active members of oncology scientific societies, and use modern public megaphone (blog, video sharing, …) to disseminate information and let society know that interventional is not a me-too product but a disruptive treatment.« less

Radar detectability studies of slow and small zodiacal dust cloud particles. I. The case of Arecibo 430 MHz meteor head echo observations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Janches, D.; Plane, J. M. C.; Feng, W.

2014-11-20

Recent model development of the Zodiacal Dust Cloud (ZDC) argues that the incoming flux of meteoric material into the Earth's upper atmosphere is mostly undetected by radars because they cannot detect small extraterrestrial particles entering the atmosphere at low velocities due to the relatively small production of electrons. In this paper, we present a new methodology utilizing meteor head echo radar observations that aims to constrain the ZDC physical model by ground-based measurements. In particular, for this work, we focus on Arecibo 430 MHz observations since this is the most sensitive radar utilized for this type of observations to date.more » For this, we integrate and employ existing comprehensive models of meteoroid ablation, ionization, and radar detection to enable accurate interpretation of radar observations and show that reasonable agreement in the hourly rates is found between model predictions and Arecibo observations when (1) we invoke the lower limit of the model predicted flux (∼16 t d{sup –1}) and (2) we estimate the ionization probability of ablating metal atoms using laboratory measurements of the ionization cross sections of high-speed metal atom beams, resulting in values up to two orders of magnitude lower than the extensively utilized figure reported by Jones for low-speed meteors. However, even at this lower limit, the model overpredicts the slow portion of the Arecibo radial velocity distributions by a factor of three, suggesting that the model requires some revision.« less

Numerical and experimental analysis of heat transfer in injector plate of hydrogen peroxide hybrid rocket motor

NASA Astrophysics Data System (ADS)

Cai, Guobiao; Li, Chengen; Tian, Hui

2016-11-01

This paper is aimed to analyze heat transfer in injector plate of hydrogen peroxide hybrid rocket motor by two-dimensional axisymmetric numerical simulations and full-scale firing tests. Long-time working, which is an advantage of hybrid rocket motor over conventional solid rocket motor, puts forward new challenges for thermal protection. Thermal environments of full-scale hybrid rocket motors designed for long-time firing tests are studied through steady-state coupled numerical simulations of flow field and heat transfer in chamber head. The motor adopts 98% hydrogen peroxide (98HP) oxidizer and hydroxyl-terminated poly-butadiene (HTPB) based fuel as the propellants. Simulation results reveal that flowing liquid 98HP in head oxidizer chamber could cool the injector plate of the motor. The cooling of 98HP is similar to the regenerative cooling in liquid rocket engines. However, the temperature of the 98HP in periphery portion of the head oxidizer chamber is higher than its boiling point. In order to prevent the liquid 98HP from unexpected decomposition, a thermal protection method for chamber head utilizing silica-phenolics annular insulating board is proposed. The simulation results show that the annular insulating board could effectively decrease the temperature of the 98HP in head oxidizer chamber. Besides, the thermal protection method for long-time working hydrogen peroxide hybrid rocket motor is verified through full-scale firing tests. The ablation of the insulating board in oxygen-rich environment is also analyzed.

Atmospheric pressure arc discharge with ablating graphite anode

NASA Astrophysics Data System (ADS)

Nemchinsky, V. A.; Raitses, Y.

2015-06-01

The anodic carbon arc discharge is used to produce carbon nanoparticles. Recent experiments with the carbon arc at atmospheric pressure helium demonstrated the enhanced ablation rate for narrow graphite anodes resulting in high deposition rates of carbonaceous products on the copper cathode (Fetterman et al 2008 Carbon 46 1322-6). The proposed model explains these results with interconnected steady-state models of the cathode and the anode processes. When considering cathode functioning, the model predicts circulation of the particles in the near-cathode region: evaporation of the cathode material, ionization of evaporated atoms and molecules in the near-cathode plasma, return of the resulting ions to the cathode, surface recombination of ions and electrons followed again by cathode evaporation etc. In the case of the low anode ablation rate, the ion acceleration in the cathode sheath provides the major cathode heating mechanism. In the case of an intensive anode ablation, an additional cathode heating is due to latent fusion heat of the atomic species evaporated from the anode and depositing at the cathode. Using the experimental arc voltage as the only input discharge parameter, the model allows us to calculate the anode ablation rate. A comparison of the results of calculations with the available experimental data shows reasonable agreement.

Safety and feasibility of single-catheter ablation using remote magnetic navigation for treatment of slow-fast atrioventricular nodal reentrant tachycardia compared to conventional ablation strategies.

PubMed

Akca, Ferdi; Schwagten, Bruno; Theuns, Dominic A J; Takens, Marieke; Musters, Paul; Szili-Torok, Tamas

2013-12-01

Ablation of atrioventricular nodal re-entrant tachycardia (AVNRT) is a highly effective procedure both with radiofrequency (RF) and cryoenergy (CE). Conventionally, it requires several diagnostic catheters and hospital admission. This study assessed the safety and efficacy of a highly simplified approach using the magnetic navigation system (MNS) compared to CE and manual RF ablation (MAN). In the MNS group a single magnetic-guided quadripolar catheter was inserted through the internal jugular vein to perform ablation. In the CE group cryomapping preceded ablation and for MAN procedures conventional ablation was performed. The following parameters were analysed: success- and recurrence rate, procedure-, fluoroscopy- and total application time. In total 69 eligible patients were treated with MNS (n = 26), CE (n = 25) and MAN (n = 16). The success rates were 100%, 100% and 94%, respectively (p = ns). The mean procedural time was 83 +/- 25 min for MNS, 117 +/- 47 min for CE and 117 +/- 55 min for MAN (P < 0.01). Total radiation time was significantly lower for MNS [0.0 min (IQR 0.0-0.0)] compared to CE [15.1 min (IQR 9.1-23.8), P < 0.001] and MAN [17.5 min (IQR 7.0-31.3), P < 0.001]. The total application time was comparable for both RF groups: 357 +/- 315 s (MNS) vs 204 +/- 177 s (MAN) (P = 0.14). No major adverse events occurred. After 3 months follow-up similar PR intervals were recorded for all patients. During a follow-up of 26 +/- 5 months recurrence rates were 3.8%, 4.0% and 6.3%, respectively, for each group. The MNS-guided single-catheter approach is a feasible and safe technique for the treatment of patients with typical AVNRT.

BIOPHYSICAL PARAMETERS DURING RADIOFREQUENCY CATHETER ABLATION OF SCAR-MEDIATED VENTRICULAR TACHYCARDIA: EPICARDIAL AND ENDOCARDIAL APPLICATIONS VIA MANUAL AND MAGNETIC NAVIGATION

PubMed Central

Bourke, Tara; Buch, Eric; Mathuria, Nilesh; Michowitz, Yoav; Yu, Ricky; Mandapati, Ravi; Shivkumar, Kalyanam; Tung, Roderick

2014-01-01

Background There is a paucity of data on biophysical parameters during radiofrequency ablation of scar-mediated ventricular tachycardia (VT). Methods and Results Data was collected from consecutive patients undergoing VT ablation with open-irrigation. Complete data was available for 372 lesions in 21 patients. The frequency of biophysical parameter changes were: >10Ω reduction (80%), bipolar EGM reduction (69%), while loss of capture was uncommon (32%). Unipolar injury current was seen in 72% of radiofrequency applications. Both EGM reduction and impedance drop were seen in 57% and a change in all 3 parameters was seen in only 20% of lesions. Late potentials were eliminated in 33%, reduced/modified in 56%, and remained after ablation in 11%. Epicardial lesions exhibited an impedance drop (90% vs 76%, p=0.002) and loss of capture (46% vs 27%, p<0.001) more frequently than endocardial lesions. Lesions delivered manually exhibited a >10Ω impedance drop (83% vs 71%, p=0.02) and an EGM reduction (71% vs 40%, p< 0.001) more frequently than lesions applied using magnetic navigation, although loss of capture, elimination of LPs, and a change in all 3 parameters were similarly observed. Conclusions VT ablation is inefficient as the majority of radiofrequency lesions do not achieve more than one targeted biophysical parameter. Only one-third of RF applications targeted at LPs result in complete elimination. Epicardial ablation within scar may be more effective than endocardial lesions and lesions applied manually may be more effective than lesions applied using magnetic navigation. New technologies directed at identifying and optimizing ablation effectiveness in scar are clinically warranted. PMID:24946895

Biophysical parameters during radiofrequency catheter ablation of scar-mediated ventricular tachycardia: epicardial and endocardial applications via manual and magnetic navigation.

PubMed

Bourke, Tara; Buch, Eric; Mathuria, Nilesh; Michowitz, Yoav; Yu, Ricky; Mandapati, Ravi; Shivkumar, Kalyanam; Tung, Roderick

2014-11-01

There is a paucity of data on biophysical parameters during radiofrequency ablation of scar-mediated ventricular tachycardia (VT). Data were collected from consecutive patients undergoing VT ablation with open-irrigation. Complete data were available for 372 lesions in 21 patients. The frequency of biophysical parameter changes were: >10Ω reduction (80%), bipolar EGM reduction (69%), while loss of capture was uncommon (32%). Unipolar injury current was seen in 72% of radiofrequency applications. Both EGM reduction and impedance drop were seen in 57% and a change in all 3 parameters was seen in only 20% of lesions. Late potentials were eliminated in 33%, reduced/modified in 56%, and remained after ablation in 11%. Epicardial lesions exhibited an impedance drop (90% vs. 76%, P = 0.002) and loss of capture (46% vs. 27%, P < 0.001) more frequently than endocardial lesions. Lesions delivered manually exhibited a >10Ω impedance drop (83% vs. 71%, P = 0.02) and an EGM reduction (71% vs. 40%, P < 0.001) more frequently than lesions applied using magnetic navigation, although loss of capture, elimination of LPs, and a change in all 3 parameters were similarly observed. VT ablation is inefficient as the majority of radiofrequency lesions do not achieve more than one targeted biophysical parameter. Only one-third of RF applications targeted at LPs result in complete elimination. Epicardial ablation within scar may be more effective than endocardial lesions, and lesions applied manually may be more effective than lesions applied using magnetic navigation. New technologies directed at identifying and optimizing ablation effectiveness in scar are clinically warranted. © 2014 Wiley Periodicals, Inc.

Percutaneous Radiofrequency Ablation with Multiple Electrodes for Medium-Sized Hepatocellular Carcinomas

PubMed Central

Lee, Jung; Yoon, Jung-Hwan; Lee, Jae Young; Kim, Se Hyung; Lee, Jeong Eun; Han, Joon Koo; Choi, Byung Ihn

2012-01-01

Objective To prospectively evaluate the safety and short-term therapeutic efficacy of switching monopolar radiofrequency ablation (RFA) with multiple electrodes to treat medium-sized (3.1-5.0 cm), hepatocellular carcinomas (HCC). Materials and Methods In this prospective study, 30 patients with single medium-sized HCCs (mean, 3.5 cm; range, 3.1-4.4 cm) were enrolled. The patients were treated under ultrasonographic guidance by percutaneous switching monopolar RFA with a multichannel RF generator and two or three internally cooled electrodes. Contrast-enhanced CT scans were obtained immediately after RFA, and the diameters and volume of the ablation zones were then measured. Follow-up CT scans were performed at the first month after ablation and every three months thereafter. Technical effectiveness, local progression and remote recurrence of HCCs were determined. Results There were no major immediate or periprocedural complications. However, there was one bile duct stricture during the follow-up period. Technical effectiveness was achieved in 29 of 30 patients (97%). The total ablation time of the procedures was 25.4 ± 8.9 minutes. The mean ablation volume was 73.8 ± 56.4 cm3 and the minimum diameter was 4.1 ± 7.3 cm. During the follow-up period (mean, 12.5 months), local tumor progression occurred in three of 29 patients (10%) with technical effectiveness, while new HCCs were detected in six of 29 patients (21%). Conclusion Switching monopolar RFA with multiple electrodes in order to achieve a sufficient ablation volume is safe and efficient. This method also showed relatively successful therapeutic effectiveness on short-term follow up for the treatment of medium-sized HCCs. PMID:22247634

Interstitial ultrasound ablation of tumors within or adjacent to bone: Contributions of preferential heating at the bone surface

NASA Astrophysics Data System (ADS)

Scott, Serena J.; Prakash, Punit; Salgaonkar, Vasant; Jones, Peter D.; Cam, Richard N.; Han, Misung; Rieke, Viola; Burdette, E. Clif; Diederich, Chris J.

2013-02-01

Preferential heating of bone due to high ultrasound attenuation may enhance thermal ablation performed with cathetercooled interstitial ultrasound applicators in or near bone. At the same time, thermally and acoustically insulating cortical bone may protect sensitive structures nearby. 3D acoustic and biothermal transient finite element models were developed to simulate temperature and thermal dose distributions during catheter-cooled interstitial ultrasound ablation near bone. Experiments in ex vivo tissues and tissue-mimicking phantoms were performed to validate the models and to quantify the temperature profiles and ablated volumes for various distances between the interstitial applicator and the bone surface. 3D patient-specific models selected to bracket the range of clinical usage were developed to investigate what types of tumors could be treated, applicator configurations, insertion paths, safety margins, and other parameters. Experiments show that preferential heating at the bone surface decreases treatment times compared to when bone is absent and that all tissue between an applicator and bone can be ablated when they are up to 2 cm apart. Simulations indicate that a 5-7 mm safety margin of normal bone is needed to protect (thermal dose < 6 CEM43°C and T < 45°C) sensitive structures behind ablated bone. In 3D patient-specific simulations, tumors 1.0-3.8 cm (L) and 1.3-3.0 cm (D) near or within bone were ablated (thermal dose > 240 CEM43°C) within 10 min without damaging the nearby spinal cord, lungs, esophagus, trachea, or major vasculature. Preferential absorption of ultrasound by bone may provide improved localization, faster treatment times, and larger treatment zones in tumors in and near bone compared to other heating modalities.

Radiofrequency Ablation in Combination with Embolization in Metachronous Recurrent Renal Cancer in Solitary Kidney after Contralateral Tumor Nephrectomy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gebauer, Bernhard, E-mail: bernhard.gebauer@charite.de; Werk, Michael; Lopez-Haenninen, Enrique

Purpose. To evaluate the feasibility and safety of minimally invasive, percutaneous techniques in metachronous recurrent renal cell cancers (RCCs) in solitary kidneys. Methods. In 4 patients, recurrent RCC was treated by radiofrequency ablation (RFA) (RITA, StarBurst) alone, and in 2 patients by RFA in combination with superselective transarterial particle-lipiodol embolization using 3 Fr microcatheters. RFA was guided by computed tomography in 5 patients, and by magnetic resonance imaging in 1 patient. Mean tumor diameter was 26.7 mm (range 10-45 mm). All interventions were technically successful; during follow-up 1 patient developed recurrent RCC, which was retreated by RFA after embolization. Results.more » No major peri- or postprocedural complications occurred. Changes in creatinine (pre- vs. post-intervention, 122 vs. 127 {mu}mol/l) and calculated creatinine clearance (pre- vs. post-intervention, 78 vs. 73 ml/min) after ablation were minimal. Conclusion. In single kidneys, percutaneous, minimally invasive techniques are safe and feasible. In large tumors, or where there are adjacent critical structures, we prefer a combination of embolization and thermal ablation (RFA)« less

From partial to full-face transplantation: total ablation and restoration, a change in the reconstructive paradigm.

PubMed

Barret, Juan P

2014-01-01

The innovation of composite vascularized allotransplantation has provided plastic and reconstructive surgeons with the ultimate tool for those patients that present with facial deformities that cannot be reconstructed with classical or more traditional techniques. Transplanting normal tissues allows for a true restorative surgery. Initial experiences included the substitution of missing anatomy, whereas after the first world's full-face transplant performed in Barcelona in March 2010, a true ablative surgery with a total restoration proved to be effective. We review the world's experience and the performance of our restorative protocol to depict this change in the reconstructive paradigm of facial transplantation. Facial transplants should be performed after a careful analysis of the defect, with a comprehensive ablation plan following esthetic units with sacrifice of all required tissues with a focus of global restoration of anatomy, aesthetics and function, respecting normal functioning muscles. Nowadays, facial transplants following strict esthetic units should restore disfigurement extending to small central areas, whereas major defects may require a total ablation and restoration with full-face transplants. Copyright © 2013 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

A probabilistic sizing tool and Monte Carlo analysis for entry vehicle ablative thermal protection systems

NASA Astrophysics Data System (ADS)

Mazzaracchio, Antonio; Marchetti, Mario

2010-03-01

Implicit ablation and thermal response software was developed to analyse and size charring ablative thermal protection systems for entry vehicles. A statistical monitor integrated into the tool, which uses the Monte Carlo technique, allows a simulation to run over stochastic series. This performs an uncertainty and sensitivity analysis, which estimates the probability of maintaining the temperature of the underlying material within specified requirements. This approach and the associated software are primarily helpful during the preliminary design phases of spacecraft thermal protection systems. They are proposed as an alternative to traditional approaches, such as the Root-Sum-Square method. The developed tool was verified by comparing the results with those from previous work on thermal protection system probabilistic sizing methodologies, which are based on an industry standard high-fidelity ablation and thermal response program. New case studies were analysed to establish thickness margins on sizing heat shields that are currently proposed for vehicles using rigid aeroshells for future aerocapture missions at Neptune, and identifying the major sources of uncertainty in the material response.

Genetic Ablation of Parietal Cells in Transgenic Mice: A New Model for Analyzing Cell Lineage Relationships in the Gastric Mucosa

NASA Astrophysics Data System (ADS)

Canfield, Victor; West, A. Brian; Goldenring, James R.; Levenson, Robert

1996-03-01

The gastric mucosa of mammalian stomach contains several differentiated cell types specialized for the secretion of acid, digestive enzymes, mucus, and hormones. Understanding whether each of these cell lineages is derived from a common stem cell has been a challenging problem. We have used a genetic approach to analyze the ontogeny of progenitor cells within mouse stomach. Herpes simplex virus 1 thymidine kinase was targeted to parietal cells within the gastric mucosa of transgenic mice, and parietal cells were ablated by treatment of animals with the antiherpetic drug ganciclovir. Ganciclovir treatment produced complete ablation of parietal cells, dissolution of gastric glands, and loss of chief and mucus-producing cells. Termination of drug treatment led to the reemergence of all major gastric epithelial cell types and restoration of glandular architecture. Our results imply the existence of a pluripotent stem cell for the gastric mucosa. Parietal cell ablation should provide a model for analyzing cell lineage relationships within the stomach as well as mechanisms underlying gastric injury and repair.

X-ray microtomography and laser ablation in the analysis of ink distribution in coated paper

DOE Office of Scientific and Technical Information (OSTI.GOV)

Myllys, M., E-mail: markko.myllys@jyu.fi; Häkkänen, H.; Korppi-Tommola, J.

A novel method was developed for studying the ink-paper interface and the structural variations of a deposited layer of ink. Combining high-resolution x-ray tomography with laser ablation, the depth profile of ink (toner), i.e., its varying thickness, could be determined in a paper substrate. X-ray tomography was used to produce the 3D structure of paper with about 1 μm spatial resolution. Laser ablation combined with optical imaging was used to produce the 3D structure of the printed layer of ink on top of that paper with about 70 nm depth resolution. Ablation depth was calibrated with an optical profilometer. It can bemore » concluded that a toner layer on a light-weight-coated paper substrate was strongly perturbed by protruding fibers of the base paper. Such fibers together with the surface topography of the base paper seem to be the major factors that control the leveling of toner and its penetration into a thinly coated paper substrate.« less

Local ablative treatments for hepatocellular carcinoma: An updated review

PubMed Central

Facciorusso, Antonio; Serviddio, Gaetano; Muscatiello, Nicola

2016-01-01

Ablative treatments currently represent the first-line option for the treatment of early stage unresectable hepatocellular carcinoma (HCC). Furthermore, they are effective as bridging/downstaging therapies before orthotopic liver transplantation. Contraindications based on size, number, and location of nodules are quite variable in literature and strictly dependent on local expertise. Among ablative therapies, radiofrequency ablation (RFA) has gained a pivotal role due to its efficacy, with a reported 5-year survival rate of 40%-70%, and safety. Although survival outcomes are similar to percutaneous ethanol injection, the lower local recurrence rate stands for a wider application of RFA in hepato-oncology. Moreover, RFA seems to be even more cost-effective than liver resection for very early HCC (single nodule ≤ 2 cm) and in the presence of two or three nodules ≤ 3 cm. There is increasing evidence that combining RFA to transarterial chemoembolization may increase the therapeutic benefit in larger HCCs without increasing the major complication rate, but more robust prospective data is still needed to validate these pivotal findings. Among other thermal treatments, microwave ablation (MWA) uses high frequency electromagnetic energy to induce tissue death via coagulation necrosis. In comparison to RFA, MWA has several theoretical advantages such as a broader zone of active heating, higher temperatures within the targeted area in a shorter treatment time and the lack of heat-sink effect. The safety concerns raised on the risks of this procedure, due to the broader and less predictable necrosis areas, have been recently overcome. However, whether MWA ability to generate a larger ablation zone will translate into a survival gain remains unknown. Other treatments, such as high-intensity focused ultrasound ablation, laser ablation, and cryoablation, are less investigated but showed promising results in early HCC patients and could be a valuable therapeutic option in the next future. PMID:27867681

Left Atrial Appendage Electrical Isolation and Concomitant Device Occlusion to Treat Persistent Atrial Fibrillation: A First-in-Human Safety, Feasibility, and Efficacy Study.

PubMed

Panikker, Sandeep; Jarman, Julian W E; Virmani, Renu; Kutys, Robert; Haldar, Shouvik; Lim, Eric; Butcher, Charles; Khan, Habib; Mantziari, Lilian; Nicol, Edward; Foran, John P; Markides, Vias; Wong, Tom

2016-07-01

Left atrial appendage (LAA) electric isolation is reported to improve persistent atrial fibrillation (AF) ablation outcomes. However, loss of LAA mechanical function may increase thromboembolic risk. Concomitant LAA electric isolation and occlusion as part of conventional AF ablation has never been tested in humans. We therefore evaluated the feasibility, safety, and efficacy of LAA electric isolation and occlusion in patients undergoing long-standing persistent AF ablation. Patients with long-standing persistent AF (age, 68±7 years; left atrium diameter, 46±3 mm; and AF duration, 25±15 months) underwent AF ablation, LAA electric isolation, and occlusion. Outcomes were compared with a balanced (1:2 ratio) control group who had AF ablation alone. Among 22 patients who underwent ablation, LAA electric isolation was possible in 20. Intraprocedural LAA reconnection occurred in 17 of 20 (85%) patients, predominantly at anterior and superior locations. All were reisolated. LAA occlusion was successful in all 20 patients. There were no major periprocedural complications. Imaging at 45 days and 9 months confirmed satisfactory device position and excluded pericardial effusion. One of twenty (5%) patients had a gap of ≥5 mm requiring anticoagulation. Nineteen of twenty (95%) patients stopped warfarin at 3 months. Without antiarrhythmic drugs, freedom from AF at 12 months after a single procedure was significantly higher in the study group (19/20, 95%) than in the control group (25/40, 63%), P=0.036. Freedom from atrial arrhythmias was demonstrated in 12 of 20 (60%) and 18 of 20 (90%) patients after 1 and ≤2 procedures (mean, 1.3), respectively. Persistent AF ablation, LAA electric isolation, and mechanical occlusion can be performed concomitantly. This technique may improve the success of persistent AF ablation while obviating the need for chronic anticoagulation. URL: https://clinicaltrials.gov. Unique identifier: NCT02028130. © 2016 American Heart Association, Inc.

Thermal ablation of intrahepatic cholangiocarcinoma: Safety, efficacy, and factors affecting local tumor progression.

PubMed

Takahashi, Edwin A; Kinsman, Kristin A; Schmit, Grant D; Atwell, Thomas D; Schmitz, John J; Welch, Brian T; Callstrom, Matthew R; Geske, Jennifer R; Kurup, A Nicholas

2018-06-04

To evaluate the safety and oncologic efficacy of percutaneous thermal ablation of intrahepatic cholangiocarcinoma (ICC) and identify risk factors for local tumor progression (LTP). Retrospective review of an institutional tumor ablation registry demonstrated that 20 patients (9 males, 11 females; mean age 62.5 ± 15.8 years) with 50 ICCs (mean size 1.8 ± 1.3 cm) were treated with percutaneous radiofrequency ablation (RFA) or microwave ablation (MWA) between 2006 and 2015. Thirty-eight of the treated ICCs (76%) were metastases that developed after surgical resection of the primary tumor. Patient demographics, procedure technical parameters, and clinical outcomes were reviewed. A Cox proportional hazards model was used to examine the risk of LTP by ablation modality. Survival analyses were performed using the Kaplan-Meier method. Mean imaging follow-up time was 41.5 ± 42.7 months. Forty-four (88%) ICCs were treated with RFA, and 6 (12%) with MWA. Eleven (22%) cases of LTP developed in 5 (25%) patients. The median time to LTP among these 11 tumors was 7.1 months (range, 2.3-22.9 months). Risk of LTP was not significantly different for ICCs treated with MWA compared to RFA (HR 2.72; 95% CI 0.58-12.84; p = 03.21). Median disease-free survival was 8.2 months (1.1-70.4 months), and median overall survival was 23.6 months (7.4-122.5 months). No major complication occurred. Percutaneous thermal ablation is a safe and effective treatment for patients with ICCs and may be particularly valuable in unresectable patients, or those who have already undergone hepatic surgery. Tumor size and ablation modality were not associated with LTP, whereas primary tumors and superficially located tumors were more likely to subsequently recur.

Preliminary characterisation of new glass reference materials (GSA-1G, GSC-1G, GSD-1G and GSE-1G) by laser ablation-inductively coupled plasma-mass spectrometry using 193 nm, 213 nm and 266 nm wavelengths

USGS Publications Warehouse

Guillong, M.; Hametner, K.; Reusser, E.; Wilson, S.A.; Gunther, D.

2005-01-01

New glass reference materials GSA-1G, GSC-1G, GSD-1G and GSE-1G have been characterised using a prototype solid state laser ablation system capable of producing wavelengths of 193 nm, 213 nm and 266 nm. This system allowed comparison of the effects of different laser wavelengths under nearly identical ablation and ICP operating conditions. The wavelengths 213 nm and 266 nm were also used at higher energy densities to evaluate the influence of energy density on quantitative analysis. In addition, the glass reference materials were analysed using commercially available 266 nm Nd:YAG and 193 nm ArF excimer lasers. Laser ablation analysis was carried out using both single spot and scanning mode ablation. Using laser ablation ICP-MS, concentrations of fifty-eight elements were determined with external calibration to the NIST SRM 610 glass reference material. Instead of applying the more common internal standardisation procedure, the total concentration of all element oxide concentrations was normalised to 100%. Major element concentrations were compared with those determined by electron microprobe. In addition to NIST SRM 610 for external calibration, USGS BCR-2G was used as a more closely matrix-matched reference material in order to compare the effect of matrix-matched and non matrix-matched calibration on quantitative analysis. The results show that the various laser wavelengths and energy densities applied produced similar results, with the exception of scanning mode ablation at 266 nm without matrix-matched calibration where deviations up to 60% from the average were found. However, results acquired using a scanning mode with a matrix-matched calibration agreed with results obtained by spot analysis. The increased abundance of large particles produced when using a scanning ablation mode with NIST SRM 610, is responsible for elemental fractionation effects caused by incomplete vaporisation of large particles in the ICP.

Flower-like Na2O nanotip synthesis via femtosecond laser ablation of glass

PubMed Central

2012-01-01

The current state-of-the-art in nanotip synthesis relies on techniques that utilize elaborate precursor chemicals, catalysts, or vacuum conditions, and any combination thereof. To realize their ultimate potential, synthesized nanotips require simpler fabrication techniques that allow for control over their final nano-morphology. We present a unique, dry, catalyst-free, and ambient condition method for creating densely clustered, flower-like, sodium oxide (Na2O) nanotips with controllable tip widths. Femtosecond laser ablation of a soda-lime glass substrate at a megahertz repetition rate, with nitrogen flow, was employed to generate nanotips with base and head widths as small as 100 and 20 nm respectively, and lengths as long as 10 μm. Control of the nanotip widths was demonstrated via laser dwell time with longer dwell times producing denser clusters of thinner nanotips. Energy dispersive X-ray analysis reveals that nanotip composition is Na2O. A new formation mechanism is proposed, involving an electrostatic effect between ionized nitrogen and polar Na2O. The synthesized nanotips may potentially be used in antibacterial and hydrogen storage applications. PMID:22809176

Predictors of free flap loss in the head and neck region: A four-year retrospective study with 451 microvascular transplants at a single centre.

PubMed

Mücke, Thomas; Ritschl, Lucas M; Roth, Maximilian; Güll, Florian D; Rau, Andrea; Grill, Sonja; Kesting, Marco R; Wolff, Klaus-Dietrich; Loeffelbein, Denys J

2016-09-01

Microvascular free flaps have become an essential part of reconstructive surgery following head and neck tumour ablation. The authors' aim was to investigate the influence of cardiovascular risk factors, preoperative irradiation, previous operations and metabolically active medication on free flap loss in order to predict patients at risk and to improve their therapy. All patients who underwent reconstructive surgery with microvascular free flaps in the head and neck region between 2009 and 2013 were retrospectively analysed. Uni- and multivariate logistic regressions were performed to determine the association between possible predictor variables for free flap loss. We included 451 patients in our analysis. The overall free flap failure rate was 4.0%. Multivariate regression analysis revealed significantly increased risks of free flap failure depending on prior attempts at microvascular transplants (p < 0.001, OR = 14.21) and length of hospitalisation (p = 0.007, OR = 1.05). With consistently low rates of flap failure, microvascular reconstruction of defects in the head and neck region has proven to be highly reliable, even in patients with comorbidities. The expertise of the operating team seems to remain the main factor affecting flap success. The only discerned independent predictor was previously failed attempts at microvascular reconstruction. Copyright © 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Radiofrequency ablation for postsurgical thyroid removal of differentiated thyroid carcinoma

PubMed Central

Xu, Dong; Wang, Lipin; Long, Bin; Ye, Xuemei; Ge, Minghua; Wang, Kejing; Guo, Liang; Li, Linfa

2016-01-01

Differentiated thyroid carcinoma (DTC) is the most common endocrine malignancy. Surgical removal with radioactive iodine therapy is recommended for recurrent thyroid carcinoma, and the postsurgical thyroid removal is critical. This study evaluated the clinical values of radiofrequency ablation (RFA) in the postsurgical thyroid removal for DTC. 35 DTC patients who had been treated by subtotal thyroidectomy received RFA for postsurgical thyroid removal. Before and two weeks after RFA, the thyroid was examined by ultrasonography and 99mTcO4 - thyroid imaging, and the serum levels of free triiodothyronine (FT3), free thyroxin (FT4), thyroid stimulating hormone (TSH) and thyroglobulin (Tg) were detected. The efficacy and complications of RFA were evaluated. Results showed that, the postsurgical thyroid removal by RFA was successfully performed in 35 patients, with no significant complication. After RFA, the average largest diameter and volume were significantly decreased in 35 patients (P > 0.05), and no obvious contrast media was observed in ablation area in the majority of patients. After RFA, the serum FT3, FT4 and Tg levels were markedly decreased (P < 0.05), and TSH level was significantly increased (P < 0.05). After RFA, radioiodine concentration in the ablation area was significantly reduced in the majority of patients. The reduction rate of thyroid update was 0.69±0.20%. DTC staging and interval between surgery and RFA had negative correlation (Pearson coefficient = -0.543; P = 0.001), with no obvious correlation among others influential factors. RFA is an effective and safe method for postsurgical thyroid removal of DTC. PMID:27186311

Treatment of lung tumours with high-energy microwave ablation: a single-centre experience.

PubMed

Ierardi, Anna Maria; Coppola, Andrea; Lucchina, Natalie; Carrafiello, Gianpaolo

2017-01-01

The purpose of our study is to report safety, technical success, effectiveness, local progression-free survival (LPFS) and overall survival of percutaneous microwave ablation (MWA) to treat lung tumours unsuitable for surgery. Nineteen patients with thirty-one tumours (mean diameter 2.4 cm) underwent percutaneous MWA in 28 sessions. Microwave ablation was carried out using a 2450-MHz generator (Emprint/Covidien, Boulder, CO, USA). Procedures were performed under cone-beam CT (CBCT) and under fluoro-CT (one session) guidance. Safety, technical success, effectiveness, LPFS and overall survival (OS) were evaluated. Safety was defined as the frequency of major and minor complications. The efficacy was evaluated on the basis of imaging characteristics, using RECIST criteria. CT follow-up was performed at 1, 3 and 6 months and yearly. LPFS was defined as the interval between MWA treatment and evidence of local recurrence, if there was any. OS was defined as the percentage of patients who were still alive. We registered one major complication (purulent hydro-pneumothorax). Minor complications were spontaneously resolved (pneumothorax and perilesional haemorrhagic effusion). Technical success was 100%. Residual disease was registered in two cases, one of whom was retreated. Complete ablation was obtained in the remaining cases (90.3%). During available follow-up (mean 9.6 months), 9/31 tumours demonstrated local recurrence. Five tumours were retreated, and none of them presented residual disease during follow-up (LPFS 22.6%). Overall survival was 93.8%. Percutaneous high-energy MWA is a safe, effective and confident technique to treat lung tumours not suitable for surgery.

Radiofrequency ablation-assisted liver resection: review of the literature and our experience

PubMed Central

Yao, Peng

2006-01-01

Background: Surgical resection is the best established treatment known to provide long-term survival and possibility of cure for liver malignancy. Intraoperative blood loss has been the major concern during major liver resections, and mortality and morbidity of surgery are clearly associated with the amount of blood loss. Different techniques have been developed to minimize intraoperative blood loss during liver resection. The radiofrequency ablation (RFA) technique has been used widely in the treatment of unresectable liver tumors. This review concentrates on the use of RFA to provide an avascular liver resection plane. Methods and results: The following review is based on two types of RFA device during liver resection: single needle probe RFA and the In-Line RFA device. Conclusion: Liver resection assisted by RFA is safe and is associated with very limited blood loss. PMID:18333135

Complications of Microwave Ablation for Liver Tumors: Results of a Multicenter Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Livraghi, Tito, E-mail: lalivra@tin.it; Meloni, Franca, E-mail: meloni@yahoo.it; Solbiati, Luigi, E-mail: lusolbia@tin.it

2012-08-15

Purpose: New technologies for microwave ablation (MWA) have been conceived, designed to achieve larger areas of necrosis compared with radiofrequency ablation (RFA). The purpose of this study was to report complications by using this technique in patients with focal liver cancer. Methods: Members of 14 Italian centers used a 2.45-GMHz generator delivering energy through a cooled miniature-choke MW antenna and a standardized protocol for follow-up. They completed a questionnaire regarding number and type of deaths, major and minor complications and side effects, and likelihood of their relationship to the procedure. Enrollment included 736 patients with 1.037 lesions: 522 had hepatocellularmore » carcinoma with cirrhosis, 187 had metastases predominantly from colorectal cancer, and 27 had cholangiocellular carcinoma. Tumor size ranged from 0.5 to 10 cm. In 13 centers, the approach used was percutaneous, in 4 videolaparoscopic, and in 3 laparotomic. Results: No deaths were reported. Major complications occurred in 22 cases (2.9%), and minor complications in 54 patients (7.3%). Complications of MWA do not differ from those RFA, both being based on the heat damage. Conclusion: Results of this multicenter study confirmed those of single-center experiences, indicating that MWA is a safe procedure, with no mortality and a low rate of major complications. The low rate of complications was probably due to precautions adopted, knowing in advance possible risk conditions, on the basis of prior RFA experience.« less

Oromandibular reconstruction with chimeric double-skin paddle flap based on peroneal vessel axis for synchronous opposite double oral cancer.

PubMed

Huang, Shih-Tsai; Liu, Wen-Chung; Chen, Lee-Wei; Yang, Kuo-Chung

2015-05-01

Synchronous double oral cancer represents the minority of cases of head and neck cancer. After tumor ablation, 2 separate oromandibular defects, even combined with a through-and-through oral defect, pose a serious reconstructive challenge. The ideal method for reconstruction remains controversial. Based on the peroneal vessel axis, a chimeric double-skin paddle peroneal fasciocutaneous or fibular osteomyocutaneous flap could be designed to accomplish the difficult reconstruction. Six male patients, each with 2 separate oromandibular defects after tumor ablation of synchronous double oral cancer, received double-skin paddle flap reconstruction with 3 peroneal fasciocutaneous and 3 fibular osteomyocutaneous flaps. All 6 flaps survived; however, complications included 1 skin paddle lost due to insufficient perfusion of a visible perforator, and 1 superficial necrosis occurring over the tip of a longer skin paddle. One postoperative intraoral infection and 1 donor site infection were also reported. During follow-up, 3 months later, 1 patient succumbed to local recurrence and bony metastasis. One patient developed a new cancer in the maxillary gingiva, and another had osteoradionecrosis 8 months later. Four patients gained acceptable cosmesis with good oral competence. A chimeric flap based on the peroneal artery could provide a segment of fibular bone, 1 or 2 skin paddles, and a cuff of the flexor hallucis longus muscle simultaneously. For 1-stage reconstruction of separate oromandibular defects after tumor ablation of synchronous double oral cancer, this design could provide all components at 1 transfer.

Japanese Board Certification System for head and neck surgeons.

PubMed

Yoshimoto, Seiichi; Nakashima, Torahiko; Fujii, Takashi; Matsuura, Kazuto; Otsuki, Naoki; Asakage, Takahiro; Fujimoto, Yasushi; Hanai, Nobuhiro; Homma, Akihiro; Monden, Nobuya; Okami, Kenji; Sugasawa, Masashi; Hasegawa, Yasuhisa; Nibu, Ken-ichi; Kamata, Shin-etsu; Kishimoto, Seiji; Kohno, Naoyuki; Fukuda, Satoshi; Hisa, Yasuo

2014-08-01

The Japan Society for Head and Neck Surgery (JSHNS) started a board certification system for head and neck surgeons in 2010. To become certified, the following qualification and experiences are required: (1) board certification as otorhinolaryngologist, (2) 2 years of clinical experience in a board-certified training facility, (3) clinical care of 100 patients with head and neck cancer under the supervision of board-certified faculty and (4) surgical experience in 50 major head and neck surgical procedures, including 20 neck dissections, under the supervision of board-certified faculty. The following scientific activities are also required during the preceding 5 years: (1) two clinical papers on head and neck cancers presented at major scientific meetings, (2) one clinical paper on head and neck cancer published in a major journal, (3) attendance at two annual meetings of JSHNS and (4) enrolment in three educational programs approved by JSHNS. The qualifying examination consists of multiple choice tests and oral examinations. A total of 151 head and neck surgeons were certified in 2010 followed by 43 in 2011 and 34 in 2012, while the membership of JSHNS dramatically increased from 1201 in 2007 to 1748 in 2013. Although the board certification system for head and neck surgeons was started only recently, it has encouraged many residents and fellows as well as established head and neck surgeons. We believe that this system will contribute to further advancement in the clinical practice for head and neck cancers in Japan. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Universal Head Ultrasound Screening in Full-term Neonates: A Retrospective Analysis of 6771 Infants.

PubMed

Ballardini, Elisa; Tarocco, Anna; Rosignoli, Chiara; Baldan, Alessandro; Borgna-Pignatti, Caterina; Garani, Giampaolo

2017-06-01

Full-term neonates may have asymptomatic cranial injuries at birth and head ultrasound screening could be useful for early diagnosis. The aim of this study was to assess the prevalence and type of intracranial abnormalities and the usefulness of head ultrasound screening in these infants. Head ultrasound screening was performed on all full-term neonates (gestational age between 37 and 42 weeks), born at Sant'Anna University Hospital of Ferrara, Italy, from June 1, 2008 through May 31, 2013. Ultrasound findings were categorized into three groups: normal, minor, and major anomalies. All full-term neonates (6771) born at our hospital underwent head ultrasound screening. One hundred fourteen of 6771 (1.7%) presented ultrasound abnormalities, whereas 6657 were normal or exhibited insignificant findings. In 101 of 114 (88.6%), abnormalities were minor, and only 13 infants had major abnormalities (0.19% of all full-term newborns). All neonates with major abnormalities presented with either microcephaly or abnormal neurological evaluations. Only one individual with major abnormalities was detected exclusively by ultrasound. The number of significant anomalies detected by head ultrasound screening in asymptomatic full-term neonates born during the study period was low. Therefore, there is no indication for routine general head ultrasound screening in these patients. However, even if low, in neonates who have neurological abnormalities, risk factors or suspected brain malformations, head ultrasound screening may play an important role in the early diagnosis of intracranial anomalies. Copyright © 2017 Elsevier Inc. All rights reserved.

High-powered microwave ablation of larger hepatocellular carcinoma: evaluation of recurrence rate and factors related to recurrence.

PubMed

Zhang, N N; Lu, W; Cheng, X J; Liu, J Y; Zhou, Y H; Li, F

2015-11-01

To evaluate the safety and efficacy of high-powered (80-100 W) percutaneous microwave ablation (MWA) at a frequency of 2450±10 MHz for treating larger hepatocellular carcinoma (HCC) and to predict the risk factors of local recurrence after high-powered MWA. The study was approved by the Institutional Review Board, and informed consent was waived because of the retrospective study design. Forty-five patients with a total of 60 lesions received high-power (80-100 W) MWA at a frequency of 2450±10 MHz through a percutaneous approach that was guided by ultrasound. Of the 60 lesions with a maximum tumour measuring 3-8 cm, 46 lesions were 3-5 cm and 14 were 5-8 cm. The complete ablation rates, local recurrence rates, complications, and short-term survival were analysed. Ten possible risk factors for local recurrence were analysed. The complete ablation rates were 82.61% for the first ablation and 100% for the second ablation for 3-5 cm lesions. The complete ablation rates were 64.29% (82.61% versus 64.29%, p=0.037) for the first ablation and 85.71% (100% versus 85.71%, p=0.055) for the second ablation for 5-8 cm lesions. Local recurrence was observed in 11 out of the 45 (24.44%) successfully treated patients. The 1-year and 2-year survival rates were 95.56% (43/45) and 86.67% (39/45), respectively. No procedure-related mortality was observed and no major bleeding, liver rupture, or liver abscesses occurred. Univariate analysis showed that a positive correlation existed between the number of lesions (p=0.022), proximity to the risk area (p=0.001), pre-ablation alpha-fetoprotein (AFP) levels (p=0.025), hepatitis B virus (HBV)-DNA replication (p=0.027) and local recurrence. Multivariate analysis identified HBV-DNA (p=0.031) and proximity to the risk area (p=0.039) as the independent prognosis factors causing postoperative HCC local recurrence. High-powered MWA of larger hepatocellular carcinomas appears to be a safe and effective treatment. HBV-DNA and proximity to the risk area appear to be independent predictors of local tumour recurrence. Copyright © 2015 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Minor Type IV Collagen α5 Chain Promotes Cancer Progression through Discoidin Domain Receptor-1

PubMed Central

Xiao, Qian; Jiang, Yan; Liu, Qingbo; Yue, Jiao; Liu, Chunying; Zhao, Xiaotong; Qiao, Yuemei; Ji, Hongbin; Chen, Jianfeng; Ge, Gaoxiang

2015-01-01

Type IV collagens (Col IV), components of basement membrane, are essential in the maintenance of tissue integrity and proper function. Alteration of Col IV is related to developmental defects and diseases, including cancer. Col IV α chains form α1α1α2, α3α4α5 and α5α5α6 protomers that further form collagen networks. Despite knowledge on the functions of major Col IV (α1α1α2), little is known whether minor Col IV (α3α4α5 and α5α5α6) plays a role in cancer. It also remains to be elucidated whether major and minor Col IV are functionally redundant. We show that minor Col IV α5 chain is indispensable in cancer development by using α5(IV)-deficient mouse model. Ablation of α5(IV) significantly impeded the development of KrasG12D-driven lung cancer without affecting major Col IV expression. Epithelial α5(IV) supports cancer cell proliferation, while endothelial α5(IV) is essential for efficient tumor angiogenesis. α5(IV), but not α1(IV), ablation impaired expression of non-integrin collagen receptor discoidin domain receptor-1 (DDR1) and downstream ERK activation in lung cancer cells and endothelial cells. Knockdown of DDR1 in lung cancer cells and endothelial cells phenocopied the cells deficient of α5(IV). Constitutively active DDR1 or MEK1 rescued the defects of α5(IV)-ablated cells. Thus, minor Col IV α5(IV) chain supports lung cancer progression via DDR1-mediated cancer cell autonomous and non-autonomous mechanisms. Minor Col IV can not be functionally compensated by abundant major Col IV. PMID:25992553

Microwave tumor ablation: cooperative academic-industry development of a high-power gas-cooled system with early clinical results

NASA Astrophysics Data System (ADS)

Brace, Christopher L.; Ziemlewicz, Timothy J.; Schefelker, Rick; Hinshaw, J. L.; Lubner, Meghan G.; Lee, Fred T.

2013-02-01

Microwave tumor ablation continues to evolve into a viable treatment option for many cancers. Current systems are poised to supplant radiofrequency ablation as the dominant percutaneous thermal therapy. Here is provided an overview of technical details and early clinical results with a high-powered, gas-cooled microwave ablation system. The system was developed with academic-industry collaboration using federal and private funding. The generator comprises three synchronous channels that each produce up to 140W at 2.45GHz. A mountable power distribution module facilitates CT imaging guidance and monitoring and reduces clutter in the sterile field. Cryogenic carbon-dioxide cools the coaxial applicator, permitting a thin applicator profile (~1.5 mm diameter) and high power delivery. A total of 106 liver tumors were treated (96 malignant, 10 benign) from December 2010 to June 2012 at a single academic institution. Mean tumor size +/- standard deviation was 2.5+/-1.3cm (range 0.5-13.9cm). Treatment time was 5.4+/-3.3min (range 1-20min). Median follow-up was 6 months (range 1-16 months). Technical success was reported in 100% of cases. Local tumor progression was noted in 4/96 (4.3%) of malignancies. The only major complication was a pleural effusion that was treated with thoracentesis. Microwave ablation with this system is an effective treatment for liver cancer. Compared to previous data from the same institution, these results suggest an increased efficacy and equivalent safety to RF ablation. Additional data from the lung and kidney support this conclusion.

A rotational ablation tool for calcified atherosclerotic plaque removal.

PubMed

Kim, Min-Hyeng; Kim, Hyung-Jung; Kim, Nicholas N; Yoon, Hae-Sung; Ahn, Sung-Hoon

2011-12-01

Atherosclerosis is a major cardiovascular disease involving accumulations of lipids, white blood cells, and other materials on the inside of artery walls. Since the calcification found in the advanced stage of atherosclerosis dramatically enhances the mechanical properties of the plaque, restoring the original lumen of the artery remains a challenge. High-speed rotational atherectomy, when performed with an ablating grinder to remove the plaque, produces much better results in the treatment of calcified plaque compared to other methods. However, the high-speed rotation of the Rotablator commercial rotational atherectomy device produces microcavitation, which should be avoided because of the serious complications it can cause. This research involves the development of a high-speed rotational ablation tool that does not generate microcavitation. It relies on surface modification to achieve the required surface roughness. The surface roughness of the tool for differential cutting was designed based on lubrication theory, and the surface of the tool was modified using Nd:YAG laser beam engraving. Electron microscope images and profiles indicated that the engraved surface of the tool had approximately 1 μm of root mean square surface roughness. The ablation experiment was performed on hydroxyapatite/polylactide composite with an elastic modulus similar to that of calcified plaque. In addition, differential cutting was verified on silicone rubber with an elastic modulus similar to that of a normal artery. The tool performance and reliability were evaluated by measuring the ablation force exerted, the size of the debris generated during ablation, and through visual inspection of the silicone rubber surface.

Comparison of Quadrapolar™ radiofrequency lesions produced by standard versus modified technique: an experimental model.

PubMed

Safakish, Ramin

2017-01-01

Lower back pain (LBP) is a global public health issue and is associated with substantial financial costs and loss of quality of life. Over the years, different literature has provided different statistics regarding the causes of the back pain. The following statistic is the closest estimation regarding our patient population. The sacroiliac (SI) joint pain is responsible for LBP in 18%-30% of individuals with LBP. Quadrapolar™ radiofrequency ablation, which involves ablation of the nerves of the SI joint using heat, is a commonly used treatment for SI joint pain. However, the standard Quadrapolar radiofrequency procedure is not always effective at ablating all the sensory nerves that cause the pain in the SI joint. One of the major limitations of the standard Quadrapolar radiofrequency procedure is that it produces small lesions of ~4 mm in diameter. Smaller lesions increase the likelihood of failure to ablate all nociceptive input. In this study, we compare the standard Quadrapolar radiofrequency ablation technique to a modified Quadrapolar ablation technique that has produced improved patient outcomes in our clinic. The methodology of the two techniques are compared. In addition, we compare results from an experimental model comparing the lesion sizes produced by the two techniques. Taken together, the findings from this study suggest that the modified Quadrapolar technique provides longer lasting relief for the back pain that is caused by SI joint dysfunction. A randomized controlled clinical trial is the next step required to quantify the difference in symptom relief and quality of life produced by the two techniques.

Discrimination of Benign and Neoplastic Mucosa with a High-Resolution Microendoscope (HRME) in Head and Neck Cancer

PubMed Central

Vila, Peter M.; Park, Chan W.; Pierce, Mark C.; Goldstein, Gregg H.; Levy, Lauren; Gurudutt, Vivek V.; Polydorides, Alexandras D.; Godbold, James H.; Teng, Marita S.; Genden, Eric M.; Miles, Brett A.; Anandasabapathy, Sharmila; Gillenwater, Ann M.; Richards-Kortum, Rebecca; Sikora, Andrew G.

2012-01-01

Background The efficacy of ablative surgery for head and neck squamous cell carcinoma (HNSCC) depends critically on obtaining negative margins. While intraoperative "frozen section" analysis of margins is a valuable adjunct, it is expensive, time-consuming, and highly dependent on pathologist expertise. Optical imaging has potential to improve the accuracy of margins by identifying cancerous tissue in real time. Our aim was to determine the accuracy and inter-rater reliability of head and neck cancer specialists using high-resolution microendoscopic (HRME) images to discriminate between cancerous and benign mucosa. Methods Thirty-eight patients diagnosed with HNSCC were enrolled in this single-center study. HRME was used to image each specimen after application of proflavine, with concurrent standard histopathologic analysis. Images were evaluated for quality control, and a training set containing representative images of benign and neoplastic tissue was assembled. After viewing training images, seven head and neck cancer specialists with no prior HRME experience reviewed 37 test images and were asked to classify each. Results The mean accuracy of all reviewers in correctly diagnosing neoplastic mucosa was 97 percent (95% Cl = 94–99%). The mean sensitivity and specificity were 98 percent (97–100%) and 92 percent (87–98%), respectively. The Fleiss kappa statistic for inter-rater reliability was 0.84 (0.77–0.91). Conclusions Medical professionals can be quickly trained to use HRME to discriminate between benign and neoplastic mucosa in the head and neck. With further development, the HRME shows promise as a method of real-time margin determination at the point of care. PMID:22492225

Use of shear waves for diagnosis and ablation monitoring of prostate cancer: a feasibility study

NASA Astrophysics Data System (ADS)

Gomez, A.; Rus, G.; Saffari, N.

2016-01-01

Prostate cancer remains as a major healthcare issue. Limitations in current diagnosis and treatment monitoring techniques imply that there is still a need for improvements. The efficacy of prostate cancer diagnosis is still low, generating under and over diagnoses. High intensity focused ultrasound ablation is an emerging treatment modality, which enables the noninvasive ablation of pathogenic tissue. Clinical trials are being carried out to evaluate its longterm efficacy as a focal treatment for prostate cancer. Successful treatment of prostate cancer using non-invasive modalities is critically dependent on accurate diagnostic means and is greatly benefited by a real-time monitoring system. While magnetic resonance imaging remains the gold standard for prostate imaging, its wider implementation for prostate cancer diagnosis remains prohibitively expensive. Conventional ultrasound is currently limited to guiding biopsy. Elastography techniques are emerging as a promising real-time imaging method, as cancer nodules are usually stiffer than adjacent healthy prostatic tissue. In this paper, a new transurethral approach is proposed, using shear waves for diagnosis and ablation monitoring of prostate cancer. A finite-difference time domain model is developed for studying the feasibility of the method, and an inverse problem technique based on genetic algorithms is proposed for reconstructing the location, size and stiffness parameters of the tumour. Preliminary results indicate that the use of shear waves for diagnosis and monitoring ablation of prostate cancer is feasible.

A preoperative mathematic model for computed tomographic guided microwave ablation treatment of hepatic dome tumors.

PubMed

Gao, Fei; Wang, Guo-Bao; Xiang, Zhan-Wang; Yang, Bin; Xue, Jing-Bing; Mo, Zhi-Qiang; Zhong, Zhi-Hui; Zhang, Tao; Zhang, Fu-Jun; Fan, Wei-Jun

2016-05-03

This study sought to prospectively evaluate the feasibility and safety of a preoperative mathematic model for computed tomographic(CT) guided microwave(MW) ablation treatment of hepatic dome tumors. This mathematic model was a regular cylinder quantifying appropriate puncture routes from the bottom up. A total of 103 patients with hepatic dome tumors were enrolled and randomly divided into 2 groups based on whether this model was used or not: Group A (using the model; n = 43) versus Group B (not using the model; n = 60). All tumors were treated by CT-guided MW ablation and follow-up contrast CT were reviewed. The average number of times for successful puncture, average ablation time, and incidence of right shoulder pain were less in Group A than Group B (1.4 vs. 2.5, P = 0.001; 8.8 vs. 11.1 minutes, P = 0.003; and 4.7% vs. 20%, P = 0.039). The technical success rate was higher in Group A than Group B (97.7% vs. 85.0%, P = 0.032). There were no significant differences between the two groups in primary and secondary technique efficacy rates (97.7% vs. 88.3%, P = 0.081; 90.0% vs. 72.7%, P = 0.314). No major complications occurred in both groups. The mathematic model of regular cylinder is feasible and safe for CT-guided MW ablation in treating hepatic dome tumors.

Enhancing hair growth in male androgenetic alopecia by a combination of fractional CO2 laser therapy and hair growth factors.

PubMed

Huang, Yue; Zhuo, Fenglin; Li, Linfeng

2017-11-01

Laser therapy and growth factors have been used as alternative treatments for male androgenetic alopecia (MAA). The aim of this study is to determine the efficacy and safety of hair growth factors alone or combined with ablative carbon dioxide (CO 2 ) fractional laser therapy in MAA. Twenty-eight men were enrolled in this randomized half-split study based on a left-head to right-head pattern. Fractional CO 2 laser treatment was unilaterally performed; hair growth factors were bilaterally applied. Six sessions with 2-week intervals were performed. Global photographs and dermoscopy assessments were performed at the baseline and 4 months after first treatment. Global photographs underwent blinded review by three independent dermatologists. Scanning electron microscopy was used to compare changes in hair-follicle phase and hair-shaft diameter. Twenty-seven participants completed the 4-month treatment schedule. One patient was lost. Mean hair density increased from 114 ± 27 to 143 ± 25/cm 2 (P < 0.001) in the combined group and from 113 ± 24 to 134 ± 19/cm 2 in the growth factor group (P < 0.001). The mean change from baseline between two groups was also compared (P = 0.003). Global photographs showed improvement in 93% (25/27) patients in the combined group and 67% (18/27) patients in the growth factor group. Under scanning electron microscopy, hair follicles appeared to transition from telogen to anagen, and hair-shaft diameter increased in five randomly selected patients. Ablative fractional CO 2 laser combined with hair growth factors may serve as an alternative treatment for MAA in individuals unwilling/unable to undergo medical or surgical treatment.

Among Patients Undergoing Ablative Treatment for Oral Cancer, Does the Provision of Oral Rehabilitation Improve the Quality of Life? A Review of the Current Literature.

PubMed

Petrosyan, Vahe; Ball, Dimity; Harrison, Rebecca; Ameerally, Phillip

2016-05-01

The impact of oral cancer and its treatment is well documented; therefore, oral rehabilitation (OH; eg, with prosthetics, osseointegrated implants, etc) can be indicated to restore some level of form, function, and well-being. The purpose of this study was to review the current literature and evaluate the impact of OH on quality of life (QoL) after ablative surgery. A systematic literature search was conducted using EMBASE, MEDLINE, and PsychINFO. The study population was composed of all articles published from 2000 to 2015. To be included, studies had to use validated, specific head and neck QoL measurements (European Organization for Research and Treatment of Cancer QoL Head and Neck Module or University of Washington QoL Questionnaire). Only 8 articles met these inclusion criteria. In this review, OH was the primary predictor variable and QoL was the primary outcome variable. The 8 articles reviewed used a range of designs, including 1 randomized controlled trial, 3 prospective cohort studies, 3 case series, and 1 single-measurement cross-sectional descriptive study. Sample sizes were small (n = 26 to 102), and there was limited randomization and control of intervention and comparator groups. The overall level of evidence was weak. All studies showed a link between OH and QoL, but the results varied in significance (P < .01 to P = .95). Overall, there appears to be improvement in QoL to varying degrees after OH. However, a more systematic use of QoL measurements is needed before any definitive conclusions can be drawn. Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

Processes to Open the Container and the Sample Catcher of the Hayabusa Returned Capsule in the Planetary Material Sample Curation Facility of JAXA

NASA Technical Reports Server (NTRS)

Fujimura, A.; Abe, M.; Yada, T.; Nakamura, T.; Noguchi, T.; Okazaki, R.; Ishibashi, Y.; Shirai, K.; Okada, T.; Yano, H.;

Gizmo is a mean word!

PubMed

Koltai, Peter J

2015-04-01

The editorial titled "Gizmos" in the April issue of Otolaryngology-Head and Neck Surgery was unfortunate. Intracapsular tonsillectomy is a rational surgical option for managing tonsillar hypertrophy causing obstructive sleep apnea in selected children. It is performed routinely by surgeons across the globe and has become the standard of care across northern Europe due to the high safety profile of the operation. The semirigid, dartlike design of the sinuplasty devices suggested the idea for an airway-specific set of high-pressure balloons. We began working on these in 2007 and had FDA approval in 2009. They are in wide use by many airway surgeons. Lingual tonsils are a frequent cause of obstructive sleep apnea, and there is no tool that manages this as effectively as endoscopic plasma ablation. We are all engaged in an honorable effort to improve care; surgical and creative skills are as important as analytical skills. Both are necessary for the continuous improvement of our work. Both are worthy of respect. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2014.

Otolith and Vertical Canal Contributions to Dynamic Postural Control

NASA Technical Reports Server (NTRS)

Black, F. Owen

1999-01-01

The objective of this project is to determine: 1) how do normal subjects adjust postural movements in response to changing or altered otolith input, for example, due to aging? and 2) how do patients adapt postural control after altered unilateral or bilateral vestibular sensory inputs such as ablative inner ear surgery or ototoxicity, respectively? The following hypotheses are under investigation: 1) selective alteration of otolith input or abnormalities of otolith receptor function will result in distinctive spatial, frequency, and temporal patterns of head movements and body postural sway dynamics. 2) subjects with reduced, altered, or absent vertical semicircular canal receptor sensitivity but normal otolith receptor function or vice versa, should show predictable alterations of body and head movement strategies essential for the control of postural sway and movement. The effect of altered postural movement control upon compensation and/or adaptation will be determined. These experiments provide data for the development of computational models of postural control in normals, vestibular deficient subjects and normal humans exposed to unusual force environments, including orbital space flight.

Energy and Mass Balance At Gran Campo Nevado, Patagonia, Chile

NASA Astrophysics Data System (ADS)

Schneider, C.; Kilian, R.; Casassa, G.

The Gran Campo Nevado (GCN) Ice Cap on Peninsula Muñoz Gamero, Chile, is lo- cated in the southernmost part of the Patagonian Andes at 53S. It comprises an ice cap and numerous outlet glaciers which mostly end in proglacial lakes at sea level. The total ice covered area sums up to approximately 250 km2. GCN forms the only major ice body between the Southern Patagonian Icefield and the Street of Magallan. Its almost unique location in the zone of the all-year westerlies makes it a region of key interest in terms of glacier and climate change studies of the westwind zone of the Southern Hemisphere. Mean annual temperature of approximately +5C at sea level and high precipitation of about 8.000 mm per year lead to an extreme turn-over of ice mass from the accumulation area of the GCN Ice Cap to the ablation areas of the outlet glaciers. Since October 1999 an automated weather station (AWS) is run continuously in the area at Bahia Bahamondes for monitoring climate parameters. From February to April 2000 an additional AWS was operated on Glaciar Lengua a small outlet glacier of GCN to the north-west. Ablation has been measured at stakes during the same pe- riod. The aim of this study, was to obtain point energy and mass balance on Glaciar Lengua. The work was conducted as part of the international and interdisciplinary working group SGran Campo NevadoT and supported by the German Research Foun- & cedil;dation (DFG). Energy balance was calculated using the bulk approach formulas and calibrated to the measured ablation. It turns out, that sensible heat transfer is the major contribution to the energy balance. Since high cloud cover rates prevail, air tempera- ture is the key factor for the energy balance of the glacier. Despite high rain fall rates, energy input from rain fall is of only minor importance to the overall energy balance. From the energy balance computed, it was possible to derive summer-time degree-day factors for Glaciar Lengua. With data from the nearby AWS at Bahia Bahamondes we computed summer ablation for the summer seasons of 1999/2000 and 2000/2001. Ablation at 45o m a.s.l. sums up to about 7 m in 1999/2000 and to 5.5 m in 2000/2001. This is in excellent accordance (+/-2%) with measurements at ablation stakes that have been drilled into the glacier on its ablation area. Surface velocity measured from the displacement of the ablation stakes is estimated to 62 m per year. A RADAR survey with ice penetrating RADAR conducted on the ablation area of Glaciar Lengua during the austral summer 2000/2001 reveals glacier depths between 120 m and 200 m ap- 1 proximately. The data sampled will allow to set up a model for mass flow and ablation at a cross-section of Glaciar Lengua at 450 m a.s.l. Glaciar Lengua has no accumu- lation area itself but obtains all of its ice mass through icefall from the heights of the GCN Ice Cap. Therefore, this model will be of fundamental importance to understand the glacial regime of the entire ice cap. 2

77 FR 13610 - Proposed Information Collection Activity; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-07

... Information Collection Activity; Comment Request Proposed Project Title: Head Start Facilities Construction, Purchase and Major Renovations. OMB No.: 0970-0193. Description: The Head Start Bureau is proposing to.... The part contains the administrative requirements applicable to Head Start and Early Head Start...

Theoretical design and evaluation of endoluminal ultrasound applicators for thermal therapy of pancreatic cancer under image guidance

NASA Astrophysics Data System (ADS)

Adams, Matthew; Scott, Serena; Salgaonkar, Vasant; Sommer, Graham; Diederich, Chris

2017-03-01

An image-guided endoluminal ultrasound applicator has been proposed for palliative and potential curative thermal therapy of pancreatic tumors. By considering a directional transducer array of planar, tubular, or curvilinear transducers, this design offers the potential for fast volumetric therapy and 3D spatial control over the energy deposition profile. Treatment of pancreatic tumor tissue would be performed in a minimally invasive fashion with the applicator positioned in the gastrointestinal (GI) lumen, and sparing of the luminal wall would be achieved with a water-cooled balloon surrounding the transducers. A theoretical evaluation of this design was performed by developing a 3D acoustic and bioheat transfer model, with temperature and thermal dose solutions obtained using a FEM solver (COMSOL Multiphysics). Parametric studies were performed on a generalized anatomical model of the pancreas, tumor, and adjacent luminal wall to determine preferred transducer configurations and frequencies for maximizing lesion volume and penetration while sparing the luminal wall. Patient-specific models of pancreatic tumors were generated from CT studies and used to assess the feasibility of performing thermal ablation or hyperthermia on small (˜2 cm diameter) pancreatic head tumors with an endoluminal applicator positioned within the duodenum. Simulation results indicate lower transducer operating frequencies (1-3 MHz) are necessary to mitigate damage to the luminal wall, and a tradeoff between penetration depth and lesion volume emerges as the degree of focusing increases. For patient-specific ablation modeling of tumors within 30 mm of the luminal wall, approximately 95% of the volume could be ablated within 15 min using a planar or lightly focused transducer configuration without duodenal damage. Over 90% of the volume could be elevated above 40°C at steady state for hyperthermia applications (e.g., radiation sensitization, drug delivery) using a tubular transducer. For tumors extending deeper into the pancreas (˜35 mm), strongly focused curvilinear transducers could ablate over 80% of the tumor volume within 15 min while minimizing damage to nearby sensitive structures.

THE MECHANISM OF LESION FORMATION BY FOCUSED ULTRASOUND ABLATION CATHETER FOR TREATMENT OF ATRIAL FIBRILLATION

PubMed Central

Sinelnikov, Y.D.; Fjield, T.; Sapozhnikov, O.A.

2009-01-01

The application of therapeutic ultrasound for the treatment of atrial fibrillation (AF) is investigated. The results of theoretical and experimental investigation of ultrasound ablation catheter are presented. The major components of the catheter are the high power cylindrical piezoelectric element and parabolic balloon reflector. Thermal elevation in the ostia of pulmonary veins is achieved by focusing the ultrasound beam in shape of a torus that transverses the myocardial tissue. High intensity ultrasound heating in the focal zone results in a lesion surrounding the pulmonary veins that creates an electrical conduction blocks and relief from AF symptoms. The success of the ablation procedure largely depends on the correct choice of reflector geometry and ultrasonic power. We present a theoretical model of the catheter’s acoustic field and bioheat transfer modeling of cardiac lesions. The application of an empirically derived relation between lesion formation and acoustic power is shown to correlate with the experimental data. Developed control methods combine the knowledge of theoretical acoustics and the thermal lesion formation simulations with experiment and thereby establish rigorous dosimetry that contributes to a safe and effective ultrasound ablation procedure. PMID:20161431

Response to palatability after area postrema lesions: a result of learned aversions.

PubMed

Tomoyasu, N; Kenney, N J

1989-11-01

The role of palatability, novelty, and food aversion in determining changes of food choice after ablation of the area postrema and caudal-medial aspect of the nucleus of the solitary tract (AP/cmNTS) is examined through a series of studies utilizing 24-h, two-food choice tests. On test days, the food that the animal has ingested since the time of lesioning or sham surgery is presented along with a novel food that varies in palatability. The results indicate that postlesion diet history is the major determinant of food choice by lesioned rats. Lesioned rats consistently take less of their familiar postlesion food than diet-matched controls, suggesting that the lesioned rats have developed an aversion to that food. Over-ingestion of the novel food may occur, but this outcome is not reliable. No indication that the animals' response to food palatability is affected by AP/cmNTS ablation was found. Learned aversion to a food ingested after AP/cmNTS ablation may account not only for changes of food preference after the lesion but also may be involved in the hypophagia and weight loss resulting from the ablation.

A matrix effect and accuracy evaluation for the determination of elements in milk powder LIBS and laser ablation/ICP-OES spectrometry.

PubMed

Gilon, N; El-Haddad, J; Stankova, A; Lei, W; Ma, Q; Motto-Ros, V; Yu, J

2011-11-01

Laser ablation coupled to inductively coupled plasma optical emission spectrometry (LA-ICP-OES) and laser-induced breakdown spectroscopy (LIBS) were investigated for the determination of Ca, Mg, Zn and Na in milk samples. The accuracy of both methods was evaluated by comparison of the concentration found using LA-ICP-OES and LIBS with classical wet digestion associated with ICP-OES determination. The results were not fully acceptable, with biases from less than 1% to more than 60%. Matrix effects were also investigated. The sample matrix can influence the temperature, electron number density (n (e)) and other excitation characteristics in the ICP. These ICP characteristics were studied and evaluated during ablation of eight milk samples. Differences in n (e) (from 8.9 to 13.8 × 10(14) cm(-3)) and rotational temperature (ranging from 3,400 to 4,400 K) occurred with no correlation with trueness. LIBS results obtained after classical external calibration procedure gave degraded accuracy, indicating a strong matrix effect. The LIBS measurements clearly showed that the major problem in LA-ICP was related to the ablation process and that LIBS spectroscopy is an excellent diagnostic tool for LA-ICP techniques.

Oesophageal Injury During AF Ablation: Techniques for Prevention

PubMed Central

Romero, Jorge; Avendano, Ricardo; Grushko, Michael; Diaz, Juan Carlos; Du, Xianfeng; Gianni, Carola; Natale, Andrea

2018-01-01

Atrial fibrillation remains the most common arrhythmia worldwide, with pulmonary vein isolation (PVI) being an essential component in the treatment of this arrhythmia. In view of the close proximity of the oesophagus with the posterior wall of the left atrium, oesophageal injury prevention has become a major concern during PVI procedures. Oesophageal changes varying from erythema to fistulas have been reported, with atrio-oesophageal fistulas being the most feared as they are associated with major morbidity and mortality. This review article provides a detailed description of the risk factors associated with oesophageal injury during ablation, along with an overview of the currently available techniques to prevent oesophageal injury. We expect that this state of the art review will deliver the tools to help electrophysiologists prevent potential oesophageal injuries, as well as increase the focus on research areas in which evidence is lacking. PMID:29636969

Transendoscopic Nd:YAG ablation of cystic lesions in 27 large animals: 1986-1995

NASA Astrophysics Data System (ADS)

Tate, Lloyd P.

1997-05-01

Hospital medical surgery records and laser logs were examined to determine the population of large animals presented to the College of Veterinary Medicine treated by laser and conventional means for cystic lesions. Cystic lesions were most frequently found in 2 anatomical locations: endometrial cysts and upper respiratory cysts. The majority of endometrial cysts were considered to be acquired, whereas the most frequently encountered upper respiratory cysts were believed to be congenital due to the fact they were most frequently seen in young animals. Nine mares, totaling 42 endometrial cysts, were presented to the Veterinary Teaching Hospital (VTH), all of which had been treated by transendoscopic Nd:YAG laser ablation. Eighteen of the respiratory cysts in the same time period were presented to the VTH, of which 10 received conventional surgery and 8 were laser photoablated. Respiratory cysts treated by conventional surgery were generally found in locations inaccessible to visualization by transendoscopic technique, and thus required a surgical approach under general anesthesia. All mares with endometrial cysts were presented with a history of conception failure. After laser ablation, a majority of the mares were able to carry a foal to term and none represented with recurrence of endometrial cysts. Horses that presented with upper respiratory cysts also did not experience recurrence of cysts; although several horses, 1 treated by laser ablation and 4 treated by conventional surgery for frontal and/or maxillary sinus cysts, had transitory sinusitis. Transendoscopic Nd:YAG photoablation of cysts appears to be a very satisfactory means of treating this particular form of lesion in large animals with minimal complications and it can be performed with the animal in a standing position as an outpatient.

MWA Versus RFA for Perivascular and Peribiliary CRLM: A Retrospective Patient- and Lesion-Based Analysis of Two Historical Cohorts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tilborg, Aukje A. J. M. van, E-mail: a.vantilborg@vumc.nl; Scheffer, Hester J.; Jong, Marcus C. de

2016-10-15

PurposeTo retrospectively analyse the safety and efficacy of radiofrequency ablation (RFA) versus microwave ablation (MWA) in the treatment of unresectable colorectal liver metastases (CRLM) in proximity to large vessels and/or major bile ducts.Method and MaterialsA database search was performed to include patients with unresectable histologically proven and/or {sup 18}F–FDG–PET avid CRLM who were treated with RFA or MWA between January 2001 and September 2014 in a single centre. All lesions that were considered to have a peribiliary and/or perivascular location were included. Univariate logistic regression analysis was performed to assess the distribution of patient, tumour and procedure characteristics. Multivariate logisticmore » regression was used to correct for potential confounders.ResultsTwo hundred and forty-three patients with 774 unresectable CRLM were ablated. One hundred and twenty-two patients (78 males; 44 females) had at least one perivascular or peribiliary lesion (n = 199). Primary efficacy rate of RFA was superior to MWA after 3 and 12 months of follow-up (P = 0.010 and P = 0.022); however, after multivariate analysis this difference was non-significant at 12 months (P = 0.078) and vanished after repeat ablations (P = 0.39). More CTCAE grade III complications occurred after MWA versus RFA (18.8 vs. 7.9 %; P = 0.094); biliary complications were especially common after peribiliary MWA (P = 0.002).ConclusionFor perivascular CRLM, RFA and MWA are both safe treatment options that appear equally effective. For peribiliary CRLM, MWA has a higher complication rate than RFA, with similar efficacy. Based on these results, it is advised to use RFA for lesions in the proximity of major bile ducts.« less

Careful treatment planning enables safe ablation of liver tumors adjacent to major blood vessels by percutaneous irreversible electroporation (IRE).

PubMed

Kos, Bor; Voigt, Peter; Miklavcic, Damijan; Moche, Michael

2015-09-01

Irreversible electroporation (IRE) is a tissue ablation method, which relies on the phenomenon of electroporation. When cells are exposed to a sufficiently electric field, the plasma membrane is disrupted and cells undergo an apoptotic or necrotic cell death. Although heating effects are known IRE is considered as non-thermal ablation technique and is currently applied to treat tumors in locations where thermal ablation techniques are contraindicated. The manufacturer of the only commercially available pulse generator for IRE recommends a voltage-to-distance ratio of 1500 to 1700 V/cm for treating tumors in the liver. However, major blood vessels can influence the electric field distribution. We present a method for treatment planning of IRE which takes the influence of blood vessels on the electric field into account; this is illustrated on a treatment of 48-year-old patient with a metastasis near the remaining hepatic vein after a right side hemi-hepatectomy. Output of the numerical treatment planning method shows that a 19.9 cm3 irreversible electroporation lesion was generated and the whole tumor was covered with at least 900 V/cm. This compares well with the volume of the hypodense lesion seen in contrast enhanced CT images taken after the IRE treatment. A significant temperature raise occurs near the electrodes. However, the hepatic vein remains open after the treatment without evidence of tumor recurrence after 6 months. Treatment planning using accurate computer models was recognized as important for electrochemotherapy and irreversible electroporation. An important finding of this study was, that the surface of the electrodes heat up significantly. Therefore the clinical user should generally avoid placing the electrodes less than 4 mm away from risk structures when following recommendations of the manufacturer.

Careful treatment planning enables safe ablation of liver tumors adjacent to major blood vessels by percutaneous irreversible electroporation (IRE)

PubMed Central

Kos, Bor; Voigt, Peter; Miklavcic, Damijan; Moche, Michael

2015-01-01

Background Irreversible electroporation (IRE) is a tissue ablation method, which relies on the phenomenon of electroporation. When cells are exposed to a sufficiently electric field, the plasma membrane is disrupted and cells undergo an apoptotic or necrotic cell death. Although heating effects are known IRE is considered as non-thermal ablation technique and is currently applied to treat tumors in locations where thermal ablation techniques are contraindicated. Materials and methods. The manufacturer of the only commercially available pulse generator for IRE recommends a voltage-to-distance ratio of 1500 to 1700 V/cm for treating tumors in the liver. However, major blood vessels can influence the electric field distribution. We present a method for treatment planning of IRE which takes the influence of blood vessels on the electric field into account; this is illustrated on a treatment of 48-year-old patient with a metastasis near the remaining hepatic vein after a right side hemi-hepatectomy. Results Output of the numerical treatment planning method shows that a 19.9 cm3 irreversible electroporation lesion was generated and the whole tumor was covered with at least 900 V/cm. This compares well with the volume of the hypodense lesion seen in contrast enhanced CT images taken after the IRE treatment. A significant temperature raise occurs near the electrodes. However, the hepatic vein remains open after the treatment without evidence of tumor recurrence after 6 months. Conclusions Treatment planning using accurate computer models was recognized as important for electrochemotherapy and irreversible electroporation. An important finding of this study was, that the surface of the electrodes heat up significantly. Therefore the clinical user should generally avoid placing the electrodes less than 4 mm away from risk structures when following recommendations of the manufacturer. PMID:26401128

Ultrasound-Guided Radiofrequency Ablation Using a New Electrode with an Electromagnetic Position Sensor for Hepatic Tumors Difficult to Place an Electrode: A Preliminary Clinical Study.

PubMed

Kang, Tae Wook; Lee, Min Woo; Song, Kyoung Doo; Rhim, Hyunchul; Lim, Hyo Keun; Kang, Wonseok; Kim, Kyunga

2017-12-01

To evaluate whether a new electrode embedded with an electromagnetic position sensor (EMPS) improves the technical feasibility of percutaneous radiofrequency ablation (RFA) in patients with hepatic tumors difficult to place an electrode under ultrasonography (US) guidance and to assess short-term therapeutic efficacy and safety. This prospective study was approved by the institutional review board, and written informed consent was obtained from all patients. Between January 2015 and December 2016, 10 patients (7 men and 3 women; age range 52-75 years) with a single hepatic tumor (median 1.4 cm; range 1.1-1.8 cm) difficult to place an electrode under US guidance were enrolled. The technical feasibility of targeting and overlapping ablation during the RFA procedure was graded using a four-point scale and analyzed using the Wilcoxon signed rank test according to the use of EMPS. In addition, the rates of technical success, local tumor progression (LTP), and major complications were assessed. The use of the new RF electrode with EMPS significantly improved the technical feasibility of targeting and overlapping ablation (p = 0.002 and p = 0.003, respectively). After treatment, the technical success rate was 100%. LTP was not found in any patient during the follow-up period (median 8 months; range 4-22 months). No major procedure-related complications occurred. The technical feasibility of percutaneous RFA improves with the use of this RF electrode embedded with an EMPS. Short-term therapeutic efficacy and safety after RFA using the electrode were promising in patients with hepatic tumors difficult to place an electrode under US guidance.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crocetti, Laura, E-mail: l.crocetti@med.unipi.it; Lencioni, Riccardo; Bozzi, Elena

The purpose of this study was to investigate the feasibility and safety of lung radiofrequency (RF) ablation by using low-perfusion-rate, expandable, multitined electrodes in an in vivo animal model. Ten New Zealand White rabbits underwent RF ablation using low-perfusion-rate, expandable, multitined electrodes (Starburst Talon; RITA Medical Systems, Mountain View, CA) and a 200-W RF generator. The electrode was positioned under fluoroscopy guidance and a single percutaneous RF ablation was performed. Saline perfusate was doped with nonionic iodinated contrast agent to render it visible on computed tomography (CT). The pump infused the saline doped with contrast agent into the lateral tinesmore » at a rate of 0.1ml/min. The planned ablation was of 3 min, with the hooks deployed to 2 cm at a target temperature of 105{sup o}C. An immediate posttreatment CT scan documented the distribution of the doped saline and the presence of immediate complications. The animals were monitored for delayed complications and sacrificed within 72 h (n = 4), 2 weeks (n = 3), or 4 weeks (n = 3). Assessment of ablation zone and adjacent structures was done at autopsy. Major complications consisted of pneumothorax requiring drainage (n = 2) and skin burn (n = 1). Immediately after the procedure the area of ablation was depicted at CT as a round, well-demarcated area, homogeneously opacified by iodinated contrast medium (mean size, 2.3 {+-} 0.8 cm). The presence of a sharply demarcated area of coagulation necrosis (mean size, 2.1 {+-} 0.4 cm) without severe damage to adjacent structures was confirmed at autopsy. In one case, euthanized at 4 weeks, in whom pneumothorax and pleural effusion were depicted, pleural fibrinous adhesions were demonstrated at autopsy. In conclusion, lung RF ablation performed in an in vivo animal model using low-perfusion-rate, expandable, multitined electrodes is feasible and safe. No severe damage to adjacent structures was demonstrated.« less

Systematic review of high-intensity focused ultrasound ablation in the treatment of breast cancer.

PubMed

Peek, M C L; Ahmed, M; Napoli, A; ten Haken, B; McWilliams, S; Usiskin, S I; Pinder, S E; van Hemelrijck, M; Douek, M

2015-07-01

A systematic review was undertaken to assess the clinical efficacy of non-invasive high-intensity focused ultrasound (HIFU) ablation in the treatment of breast cancer. MEDLINE/PubMed library databases were used to identify all studies published up to December 2013 that evaluated the role of HIFU ablation in the treatment of breast cancer. Studies were eligible if they were performed on patients with breast cancer and objectively recorded at least one clinical outcome measure of response (imaging, histopathological or cosmetic) to HIFU treatment. Nine studies fulfilled the inclusion criteria. The absence of tumour or residual tumour after treatment was reported for 95·8 per cent of patients (160 of 167). No residual tumour was found in 46·2 per cent (55 of 119; range 17-100 per cent), less than 10 per cent residual tumour in 29·4 per cent (35 of 119; range 0-53 per cent), and between 10 and 90 per cent residual tumour in 22·7 per cent (27 of 119; range 0-60 per cent). The most common complication associated with HIFU ablation was pain (40·1 per cent) and less frequently oedema (16·8 per cent), skin burn (4·2 per cent) and pectoralis major injury (3·6 per cent). MRI showed an absence of contrast enhancement after treatment in 82 per cent of patients (31 of 38; range 50-100 per cent), indicative of coagulative necrosis. Correlation of contrast enhancement on pretreatment and post-treatment MRI successfully predicted the presence of residual disease. HIFU treatment can induce coagulative necrosis in breast cancers. Complete ablation has not been reported consistently on histopathology and no imaging modality has been able confidently to predict the percentage of complete ablation. Consistent tumour and margin necrosis with reliable follow-up imaging are required before HIFU ablation can be evaluated within large, prospective clinical trials. © 2015 BJS Society Ltd Published by John Wiley & Sons Ltd.

Catheter ablation of ventricular tachycardias using remote magnetic navigation: a consecutive case-control study.

PubMed

Szili-Torok, Tamas; Schwagten, Bruno; Akca, Ferdi; Bauernfeind, Tamas; Abkenari, Lara Dabiri; Haitsma, David; Van Belle, Yves; Groot, Natasja D E; Jordaens, Luc

2012-09-01

Remote Magnetic Navigation for VT Ablation. This study aimed to compare acute and late outcomes of VT ablation using the magnetic navigation system (MNS) to manual techniques (MAN) in patients with (SHD) and without (NSHD) structural heart disease. Ablation data of 113 consecutive patients (43 SHD, 70 NSHD) with ventricular tachycardia treated with catheter ablation at our center were analyzed. Success rate, complications, procedure, fluoroscopy, and ablation times, and recurrence rates were systematically recorded for all patients. A total of 72 patients were included in the MNS group and 41 patients were included in the MAN group. Patient age, gender, and right ventricular and left ventricular VT were equally distributed. Acute success was achieved in 59 patients in the MNS group (82%) versus 27 (66%) patients in the MAN group (P = 0.046). Overall procedural time (177 ± 79 vs 232 ± 99 minutes, P < 0.01) and mean patient fluoroscopy time (27 ± 19 vs 56 ± 32 minutes, P < 0.001) were all significantly lower using MNS. In NSHD pts, higher acute success was achieved with MNS (83,7% vs 61.9%, P = 0.049), with shorter procedure times (151 ± 57 vs 210 ± 96, P = 0.011), whereas in SHD-VT these were not significantly different. No major complications occurred in the MNS group (0%) versus 1 cardiac tamponade and 1 significantly damaged ICD lead in the MAN group (4.9%, NS). After follow-up (20 ± 11 vs 20 ± 10 months, NS), VT recurred in 14 pts (23.7%) in the MNS group versus 12 pts (44.4%) in the MAN group (P = 0.047). The use of MNS offers advantages for ablation of NSHD-VT, while it offers similar efficacy for SHD-VT. (J Cardiovasc Electrophysiol, Vol. 23, pp. 948-954, September 2012). © 2012 Wiley Periodicals, Inc.

Role of dual-laser ablation in controlling the Pb depletion in epitaxial growth of Pb(Zr0.52Ti0.48)O3 thin films with enhanced surface quality and ferroelectric properties

NASA Astrophysics Data System (ADS)

Mukherjee, Devajyoti; Hyde, Robert; Mukherjee, Pritish; Srikanth, Hariharan; Witanachchi, Sarath

2012-03-01

Pb depletion in Pb(Zr0.52Ti0.48)O3 (PZT) thin films has remained as a major setback in the growth of defect-free PZT thin films by pulsed laser ablation techniques. At low excimer (KrF) laser fluences, the high volatility of Pb in PZT leads to non-congruent target ablation and, consequently, non-stoichiometric films, whereas, at high laser fluences, the inherent ejection of molten droplets from the target leads to particulate laden films, which is undesirable in heterostructure growth. To overcome these issues, a dual-laser ablation (PLDDL) process that combines an excimer (KrF) laser and CO2 laser pulses was used to grow epitaxial PZT films on SrTiO3 (100) and MgO (100) substrates. Intensified-charge-coupled-detector (ICCD) images and optical emission spectroscopy of the laser-ablated plumes in PLDDL revealed a broader angular expansion and enhanced excitation of the ablated species as compared to those for single-laser ablation (PLDSL). This led to the growth of particulate-free PZT films with higher Pb content, better crystallinity, and lower surface roughness as compared to those deposited using PLDSL. For FE measurements, PZT capacitors were fabricated in situ using the latticed-matched metallic oxide, La0.7Sr0.3MnO3, as the top and bottom electrodes. PZT films deposited using PLDDL exhibited enhanced polarization for all driving voltages as compared to those deposited using PLDSL. A highest remanent polarization (Pr) of ˜91 μC/cm2 and low coercive field of ˜40 kV/cm was recorded at 9 V driving voltage. Fatigue characterization revealed that PZT films deposited using PLDDL showed unchanging polarization, even after 109 switching cycles.

Meta-analysis of randomized trials of percutaneous transluminal coronary angioplasty versus atherectomy, cutting balloon atherotomy, or laser angioplasty.

PubMed

Bittl, John A; Chew, Derek P; Topol, Eric J; Kong, David F; Califf, Robert M

2004-03-17

We conducted a systematic overview (meta-analysis) of randomized trials of balloon angioplasty versus coronary atherectomy, laser angioplasty, or cutting balloon atherotomy to evaluate the effects of plaque modification during percutaneous coronary intervention. Several mechanical approaches have been developed that ablate or section atheromatous plaque during percutaneous coronary interventions to optimize acute results, minimize intimal injury, and reduce complications and restenosis. Sixteen trials (9,222 patients) constitute the randomized controlled experience with atherectomy, laser, or atherotomy versus balloon angioplasty with or without coronary stenting. Each trial tested the hypothesis that ablative therapy would result in better clinical or angiographic results than balloon dilation alone. Short-term death rates (<31 days) were not improved by the use of ablative procedures (0.3% vs. 0.4%, odds ratio [OR] 0.94 [95% confidence interval 0.46 to 1.92]), but periprocedural myocardial infarctions (4.4% vs. 2.5%, OR 1.83 [95% CI 1.43 to 2.34]) and major adverse cardiac events (5.1% vs. 3.3%, OR 1.54 [95% CI 1.25 to 1.89]) were increased. Angiographic restenosis rates (6,958 patients) were not improved with the ablative devices (38.9% vs. 37.4%, OR 1.06 [95% CI 0.97 to 1.17]). No reduction in revascularization rates (25.2% vs. 24.5%, OR 1.04 [95% CI 0.94 to 1.14]) or cumulative adverse cardiac events rates up to one year after treatment were seen with ablative devices (27.8% vs. 26.1%, OR 1.09 [95% CI 0.99 to 1.20]). The combined experience from randomized trials suggests that ablative devices failed to achieve predefined clinical and angiographic outcomes. This meta-analysis does not support the hypothesis that routine ablation or sectioning of atheromatous tissue is beneficial during percutaneous coronary interventions.

Mitomycin-C in corneal surface excimer laser ablation techniques: a report by the American Academy of Ophthalmology.

PubMed

Majmudar, Parag A; Schallhorn, Steven C; Cason, John B; Donaldson, Kendall E; Kymionis, George D; Shtein, Roni M; Verity, Steven M; Farjo, Ayad A

2015-06-01

To review the published literature assessing the efficacy and safety of mitomycin-C (MMC) as an adjunctive treatment in corneal surface excimer laser ablation procedures. Literature searches of the PubMed and Cochrane Library databases were last conducted on August 19, 2014, without language or date limitations. The searches retrieved a total of 239 references. Of these, members of the Ophthalmic Technology Assessment Committee Refractive Management/Intervention Panel selected 26 articles that were considered to be of high or medium clinical relevance, and the panel methodologist rated each article according to the strength of evidence. Ten studies were rated as level I evidence, 5 studies were rated as level II evidence, and the remaining 11 studies were rated as level III evidence. The majority of the articles surveyed in this report support the role of MMC as an adjunctive treatment in surface ablation procedures. When MMC is applied in the appropriate concentration and confined to the central cornea, the incidence of post-surface ablation haze is decreased. Although a minority of studies that evaluated endothelial cell density (ECD) reported an MMC-related decrease in ECD, no clinical adverse outcomes were reported. Over the past 15 years, the use of MMC during surgery in surface ablation has become widespread. There is good evidence of the effectiveness of MMC when used intraoperatively as prophylaxis against haze in higher myopic ablations. Although there are reports of decreased endothelial counts after the administration of MMC during surgery, the clinical significance of this finding remains uncertain, because no adverse outcomes were reported with as much as 5 years of follow-up. Optimal dosage, effectiveness as prophylaxis in lower myopic and hyperopic ablations, and long-term safety, particularly in eyes with reduced corneal endothelial cell counts from prior intraocular surgery, have yet to be established. Copyright © 2015 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Tissue ablation accelerated by peripheral scanning mode with high-intensity focused ultrasound: a study on isolated porcine liver perfusion.

PubMed

Bu, Rui; Yin, Li; Yang, Han; Wang, Qi; Wu, Feng; Zou, Jian Zhong

2013-08-01

The aims of this study were to investigate the feasibility of accelerated tissue ablation using a peripheral scanning mode with high-intensity focused ultrasound (HIFU) and to explore the effect of flow rate on total energy consumption of the target tissues. Using a model of isolated porcine liver perfusion via the portal vein and hepatic artery, we conducted a scanning protocol along the periphery of the target tissues using linear-scanned HIFU to carefully adjust the varying focal depth, generator power, scanning velocity and line-by-line interval over the entire ablation range. Porcine livers were divided into four ablation groups: group 1, n = 12, with dual-vessel perfusion; group 2, n = 11, with portal vein perfusion alone; group 3, n = 10, with hepatic artery perfusion alone; and group 4, n = 11, control group with no-flow perfusion. The samples were cut open consecutively at a thickness of 3 mm, and the actual ablation ranges were calculated along the periphery of the target tissues after triphenyl tetrazolium chloride staining. Total energy consumption was calculated as the sum of the energy requirements at various focal depths in each group. On the basis of the pre-supposed scanning protocol, the peripheral region of the target tissue formed a complete coagulation necrosis barrier in each group with varying dose combinations, and the volume of the peripheral necrotic area did not differ significantly among the four groups (p > 0.05). Furthermore, total energy consumption in each group significantly decreased with the corresponding decrease in flow rate (p < 0.01). This study revealed that the complete peripheral necrosis barrier within the target tissues can defined using linear-scanned HIFU in an isolated porcine liver perfusion model. Additionally, the flow rate in the major hepatic vessels may play an important role in the use of the peripheral ablation mode, and this novel mode of ablation may enhance the therapeutic efficacy and tolerability of the treatment of large tumors using HIFU ablation. Copyright © 2013 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

77 FR 31857 - Submission for OMB Review; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-30

... OMB Review; Comment Request Title: 1309 Head Start Facilities Construction, Purchase and Major Renovations. OMB No.: 0970-0193. Description: The Head Start Bureau is proposing to renew, without changes... administrative requirements applicable to Head Start and Early Head Start grantees, when applying for funding to...

Urodynamic changes in patients with anterior urethral valves: before and after endoscopic valve ablation.

PubMed

Kajbafzadeh, Abdol-Mohammad; Payabvash, Seyedmehdi; Karimian, Golnar

2007-08-01

To retrospectively review a series of children with anterior urethral valves (AUV), with emphasis on patterns of urodynamic change and long-term outcome of endoscopic treatment. We reviewed the medical records of eight patients who had undergone thorough radiological and urodynamic exams before and after treatment. The diagnosis of AUV was based on radiological imaging and confirmed by urethrocystoscopy. The valves were ablated through either transurethral fulguration or resection. The upper urinary tracts were studied by renal scan and ultrasonography before and after the procedure. Bladder function was assessed urodynamically 3 months after surgery. Uroflowmetry was performed as soon as the children were toilet trained. Endoscopic ablation of AUV was successful in all cases and no surgical complications occurred. The initial symptoms resolved in all boys. VUR disappeared in two out of three patients, and five children had bladder trabeculation that was resolved after surgery. The final outcome was successful in seven patients (88%). The major urodynamic dysfunction was bladder hypercontractility that resolved following valve ablation. The mean maximum voiding detrusor pressure (P(detmax)) decreased from 213.2+/-17.9 cmH(2)O to 80.7+/-9.9 cmH(2)O, 6 months after treatment (P<0.001). None of the patients had low-compliant bladder, detrusor instability or myogenic failure. The voiding pattern in all toilet-trained patients was staccato and of an interrupted shape prior to surgery, but changed to a normal bell-shaped voiding pattern following valve ablation. AUV should be considered in the differential diagnosis of patients presenting with infravesical obstruction. We recommend endoscopic valve ablation as the treatment of choice.

Pulmonary Vein Isolation Alone Versus Additional Linear Ablation in Patients With Persistent Atrial Fibrillation Converted to Paroxysmal Type With Antiarrhythmic Drug Therapy: A Multicenter, Prospective, Randomized Study.

PubMed

Yu, Hee Tae; Shim, Jaemin; Park, Junbeom; Kim, In-Soo; Kim, Tae-Hoon; Uhm, Jae-Sun; Joung, Boyoung; Lee, Moon-Hyoung; Kim, Young-Hoon; Pak, Hui-Nam

2017-06-01

Atrial fibrillation (AF) type can vary depending on condition and timing, and some patients who initially present with persistent AF may be changed to paroxysmal AF after antiarrhythmic drug medication and cardioversion. We investigated whether circumferential pulmonary vein isolation (CPVI) alone is an effective rhythm control strategy in patients with persistent AF to paroxysmal AF. We enrolled 113 patients with persistent AF to paroxysmal AF (male 75%, 60.4±10.1 years old) who underwent catheter ablation for nonvalvular AF at 3 tertiary hospitals. The participants were randomly assigned to 2 groups: CPVI alone (n=59) or CPVI plus linear ablation (CPVI+Line; posterior box+anterior line, n=54). Compared with the CPVI+Line, CPVI alone required shorter procedure (187.2±58.0 versus 211.2±63.9 min; P =0.043) and ablation times (4922.1±1110.5 versus 6205.7±1425.2 s; P <0.001) without difference in procedure-related major complication (3% versus 2%; P =0.611). Antiarrhythmic drug utility rates after ablation were not different between the 2 groups (22% versus 30%; P =0.356). Overall, AF-free survival (log-rank; P =0.206) and AF and antiarrhythmic drug-free survival (log-rank; P =0.321) were not different between groups. CPVI alone is an effective rhythm control strategy with a shorter procedure time in persistent AF patients converted to paroxysmal AF compared with CPVI with linear ablation. URL: https://www.clinicaltrials.gov. Unique identifier: NCT02176616. © 2017 American Heart Association, Inc.

Percutaneous microwave ablation of hepatocellular carcinoma with a gas-cooled system: initial clinical results with 107 tumors.

PubMed

Ziemlewicz, Timothy J; Hinshaw, J Louis; Lubner, Meghan G; Brace, Christopher L; Alexander, Marci L; Agarwal, Parul; Lee, Fred T

2015-01-01

To retrospectively review the results of hepatocellular carcinoma (HCC) treatment with a high-power, gas-cooled, multiantenna-capable microwave device. A total of 107 HCCs in 75 patients (65 men) with a mean age of 61 years (range, 44-82 y) were treated via percutaneous approach. Combination microwave ablation and transarterial chemoembolization was performed for 22 tumors in 19 patients with tumors larger than 4 cm (n = 10), tumors larger than 3 cm with ill-defined margins (n = 7), or lesions not identified with ultrasonography (n = 5). Mean tumor size was 2.1 cm (range, 0.5-4.2 cm), with median follow-up of 14 months, for ablation alone; compared with 3.7 cm (range, 1.0-7.0 cm) and 12 months, respectively, for combination therapy. All procedures were performed with a single microwave system (Certus 140) with one to three 17-gauge antennas. Mean ablation time was 5.3 minutes (range, 1-11.5 min). All treatments were considered technically successful in a single session. Primary technique effectiveness rates were 91.6% (98 of 107) overall, 93.7% (89 of 95) for tumors 4 cm or smaller, and 75.0% (nine of 12) for tumors larger than 4 cm; and 91.8% (78 of 85) for ablation alone and 90.9% (20 of 22) for combination therapy. There was no major complication or procedure-related mortality. The overall survival rate was 76.0% at a median 14-month clinical follow-up, with most deaths related to end-stage liver disease (n = 11) or multifocal HCC (n = 5). Treating HCC with a gas-cooled, multiantenna-capable microwave ablation device is safe, with promising treatment effectiveness. Copyright © 2015 SIR. Published by Elsevier Inc. All rights reserved.

Efficacy and Safety of Radiofrequency Ablation for Benign Thyroid Nodules: A Prospective Multicenter Study

PubMed Central

Jung, So Lyung; Lee, Jeong Hyun; Shong, Young Kee; Sung, Jin Yong; Kim, Kyu Sun; Lee, Ducky; Kim, Ji-hoon; Baek, Seon Mi; Sim, Jung Suk; Na, Dong Gyu

2018-01-01

Objective To assess the efficacy and safety of thyroid radiofrequency (RF) ablation for benign thyroid nodules by trained radiologists according to a unified protocol in a multi-center study. Materials and Methods From 2010 to 2011, 345 nodules from 345 patients (M:F = 43:302; mean age ± SD = 46.0 ± 12.7 years, range = 15–79) who met eligibility criteria were enrolled from five institutions. At pre-ablation, the mean volume was 14.2 ± 13.2 mL (1.1–80.8 mL). For 12 months or longer after treatment, 276 lesions, consisting of 248 solid and 28 predominantly cystic nodules, were followed. All operators performed RF ablation with a cool-tip RF system and two standard techniques (a transisthmic approach and the moving-shot technique). Volume reduction at 12 months after RF ablation (the primary outcome), therapeutic success, improvement of symptoms as well as of cosmetic problems, and complications were evaluated. Multiple linear regression analysis was applied to identify factors that were independently predictive of volume reduction. Results The mean volume reduction at 12 months was 80.3% (n = 276) and at the 24-, 36-, 48-, and 60-month follow-ups 84.3% (n = 198), 89.2% (n = 128), 91.9% (n = 57), and 95.3% (n = 6), respectively. Our therapeutic success was 97.8%. Both mean symptom and cosmetic scores showed significant improvements (p < 0.001). The rate of major complications was 1.0% (3/276). Solidity and applied energy were independent factors that predicted volume reduction. Conclusion Radiofrequency ablation performed by trained radiologists from multiple institutions using a unified protocol and similar devices was effective and safe for treating benign thyroid nodules. PMID:29354014

Common Atrial Fibrillation Risk Alleles at 4q25 Predict Recurrence after Catheter-based Atrial Fibrillation Ablation

PubMed Central

Shoemaker, M. Benjamin; Muhammad, Raafia; Parvez, Babar; White, Brenda W.; Streur, Megan; Song, Yanna; Stubblefield, Tanya; Kucera, Gayle; Blair, Marcia; Rytlewski, Jason; Parvathaneni, Sunthosh; Nagarakanti, Rangadham; Saavedra, Pablo; Ellis, Christopher; Whalen, S. Patrick; Roden, Dan M; Darbar, Dawood

2012-01-01

Background Common single nucleotide polymorphisms (SNPs) at chromosome 4q25 (rs2200733, rs10033464) are associated with both lone and typical AF. Risk alleles at 4q25 have recently been shown to predict recurrence of AF after ablation in a population of predominately lone AF, but lone AF represents only 5–30% of AF cases. Objective To test the hypothesis that 4q25 AF risk alleles can predict response to AF ablation in the majority of AF cases. Methods Patients enrolled in the Vanderbilt AF Registry underwent 378 catheter-based AF ablations (median age 60 years, 71% male, 89% typical AF) between 2004 and 2011. The primary endpoint was time to recurrence of any non-sinus atrial tachyarrhythmia (atrial tachycardia, atrial flutter, or AF; [AT/AF]). Results Two-hundred AT/AF recurrences (53%) were observed. In multivariable analysis, the rs2200733 risk allele predicted a 24% shorter recurrence-free time (survival time ratio 0.76 95% confidence interval [CI] 0.6–0.95, P=0.016) compared with wild-type. The heterozygous haplotype demonstrated a 21% shorter recurrence-free time (survival time ratio = 0.79, 95% CI 0.62–0.99) and the homozygous risk allele carriers a 39% shorter recurrence-free time (survival time ratio = 0.61, 95% CI 0.37–1.0) (P=0.037). Conclusion Risk alleles at the 4q25 loci predict impaired clinical response to AF ablation in a population of predominately typical AF patients. Our findings suggest the rs2200733 polymorphism may hold promise as an as an objectively measured patient characteristic that can used as a clinical tool for selection of patients for AF ablation. PMID:23178686

Remote magnetic versus manual catheter navigation for circumferential pulmonary vein ablation in patients with atrial fibrillation.

PubMed

Lüthje, Lars; Vollmann, Dirk; Seegers, Joachim; Dorenkamp, Marc; Sohns, Christian; Hasenfuss, Gerd; Zabel, Markus

2011-11-01

Only limited data exist on the clinical utility of remote magnetic navigation (RMN) for pulmonary vein (PV) ablation. Aim of this prospective study was to evaluate the safety and efficacy of RMN for PV isolation as compared to the manual (CON) approach. A total of 161 consecutive patients undergoing circumferential PV isolation were included. Open-irrigated 3.5 mm ablation catheters under the guidance of a mapping system were used. The catheter was navigated with the Stereotaxis Niobe II system in the RMN group (n = 107) and guided manually in the CON group (n = 54). Electrical isolation of all PVs was achieved in 90% of the patients in the RMN group and in 87% in the CON group (p = 0.6). All subjects were followed every 3 months by 7d Holter-ECG. At 12 months of follow-up, 53.5% (RMN) and 55.5% (CON) of the patients were free of any left atrial tachycardia/atrial fibrillation (AF) episode (p = 0.57). Free of symptomatic AF recurrence were 66.3% (RMN) and 62.1% (CON) of the subjects (p = 0.80). Use of RMN was associated with longer procedure duration (p < 0.0001), ablation times (p < 0.0001), and RF current application duration (p < 0.05). In contrast, fluoroscopy time was lower in the RMN group (p < 0.0001). Major complications occurred in 6 of 161 procedures (3.7%), with no significant difference between groups (p = 0.75). RMN-guided PV ablation provides comparable acute and long-term success rates as compared to manual navigation. Procedural complication rates are similar. The use of RMN is associated with markedly reduced fluoroscopy time, but prolonged ablation and procedure duration.

MAGNETIC VT study: a prospective, multicenter, post-market randomized controlled trial comparing VT ablation outcomes using remote magnetic navigation-guided substrate mapping and ablation versus manual approach in a low LVEF population.

PubMed

Di Biase, Luigi; Tung, Roderick; Szili-Torok, Tamás; Burkhardt, J David; Weiss, Peter; Tavernier, Rene; Berman, Adam E; Wissner, Erik; Spear, William; Chen, Xu; Neužil, Petr; Skoda, Jan; Lakkireddy, Dhanunjaya; Schwagten, Bruno; Lock, Ken; Natale, Andrea

2017-04-01

Patients with ischemic cardiomyopathy (ICM) are prone to scar-related ventricular tachycardia (VT). The success of VT ablation depends on accurate arrhythmogenic substrate localization, followed by optimal delivery of energy provided by constant electrode-tissue contact. Current manual and remote magnetic navigation (RMN)-guided ablation strategies aim to identify a reentry circuit and to target a critical isthmus through activation and entrainment mapping during ongoing tachycardia. The MAGNETIC VT trial will assess if VT ablation using the Niobe™ ES magnetic navigation system results in superior outcomes compared to a manual approach in subjects with ischemic scar VT and low ejection fraction. This is a randomized, single-blind, prospective, multicenter post-market study. A total of 386 subjects (193 per group) will be enrolled and randomized 1:1 between treatment with the Niobe ES system and treatment via a manual procedure at up to 20 sites. The study population will consist of patients with ischemic cardiomyopathy with left ventricular ejection fraction (LVEF) of ≤35% and implantable cardioverter defibrillator (ICD) who have sustained monomorphic VT. The primary study endpoint is freedom from any recurrence of VT through 12 months. The secondary endpoints are acute success; freedom from any VT at 1 year in a large-scar subpopulation; procedure-related major adverse events; and mortality rate through 12-month follow-up. Follow-up will consist of visits at 3, 6, 9, and 12 months, all of which will include ICD interrogation. The MAGNETIC VT trial will help determine whether substrate-based ablation of VT with RMN has clinical advantages over manual catheter manipulation. Clinicaltrials.gov identifier: NCT02637947.

Radiofrequency ablation of neuroendocrine liver metastases: the Middlesex experience.

PubMed

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

2005-01-01

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

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

PubMed

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

2017-02-01

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

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

PubMed

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

2017-09-01

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

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

PubMed

Kołodziejczak, Anna Maria; Rotsztejn, Helena

2017-03-01

The assessment of the signs of aging within eyes area in cutometric (skin elasticity) and mexametric (discoloration and severity of erythema) examination after the treatment with: non-ablative fractional laser, non-ablative radiofrequency (RF) and intense light source (IPL). This study included 71 patients, aged 33-63 years (the average age was 45.81) with Fitzpatrick skin type II and III. 24 patients received 5 successive treatment sessions with a 1,410-nm non-ablative fractional laser in two-week intervals, 23 patients received 5 successive treatment sessions with a non-ablative RF in one-week intervals and 24 patients received 5 successive treatment sessions with an IPL in two-week intervals. The treatment was performed for the skin in the eye area. The Cutometer and Mexameter (Courage + Khazaka electronic) reference test was used as an objective method for the assessment of skin properties: elasticity, skin pigmentation and erythema. Measurements of skin elasticity were made in three or four sites within eye area. The results of cutometric measurements for R7 showed the improvement in skin elasticity in case of all treatment methods. The largest statistically significant improvement (p < .0001) was observed in case of laser and RF, during treatment sessions, at sites at upper and lower eyelid. The smallest change in skin elasticity for the laser, RF and IPL - p = .017, p = .003 and p = .001, respectively-was observed in a site within the outer corner of the eye. In all sites of measurements and for all methods, the greatest improvement in skin elasticity was demonstrated between the first and second measurement (after 3rd procedures). The majority of the results of mexametric measurements-MEX (melanin level) and ERYT (the severity of erythema) are statistically insignificant. Fractional, non-ablative laser, non-ablation RF and intense light source can be considered as methods significantly affecting elasticity and to a lesser extent erythema and skin pigmentation around the eyes. Fractional non-ablative laser is a method which, in comparison to other methods, has the greatest impact on skin viscoelasticity. These procedures are well tolerated and are associated with a low risk of side effects. © 2017 Wiley Periodicals, Inc.

SHOCKED AND SCORCHED: THE TAIL OF A TADPOLE IN AN INTERSTELLAR POND

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sahai, R.; Morris, M. R.; Claussen, M. J., E-mail: raghvendra.sahai@jpl.nasa.gov

2012-05-20

We report multi-wavelength observations of the far-infrared source IRAS 20324+4057, including high-resolution optical imaging with the Hubble Space Telescope, and ground-based near-infrared, millimeter-wave and radio observations. These data show an extended, limb-brightened, tadpole-shaped nebula with a bright, compact, cometary nebula located inside the tadpole head. Our molecular line observations indicate that the Tadpole is predominantly molecular with a total gas mass exceeding 3.7 M{sub Sun }. Our radio continuum imaging and archival Spitzer IRAC images show the presence of additional tadpole-shaped objects in the vicinity of IRAS 20324+4057 that share a common east-west head-tail orientation: we propose that these structuresmore » are small, dense molecular cores that originated in the Cygnus cloud and are now being (1) photoevaporated by the ultraviolet radiation field of the Cyg OB2 No. 8 cluster located to the northwest; and (2) shaped by ram pressure of a distant wind source or sources located to the west, blowing ablated and photoevaporated material from their heads eastward. The ripples in the tail of the Tadpole are interpreted in terms of instabilities at the interface between the ambient wind and the dense medium of the former.« less

Genetic Dissection of Photoperiod Response Based on GWAS of Pre-Anthesis Phase Duration in Spring Barley

PubMed Central

Alqudah, Ahmad M.; Sharma, Rajiv; Pasam, Raj K.; Graner, Andreas; Kilian, Benjamin; Schnurbusch, Thorsten

2014-01-01

Heading time is a complex trait, and natural variation in photoperiod responses is a major factor controlling time to heading, adaptation and grain yield. In barley, previous heading time studies have been mainly conducted under field conditions to measure total days to heading. We followed a novel approach and studied the natural variation of time to heading in a world-wide spring barley collection (218 accessions), comprising of 95 photoperiod-sensitive (Ppd-H1) and 123 accessions with reduced photoperiod sensitivity (ppd-H1) to long-day (LD) through dissecting pre-anthesis development into four major stages and sub-phases. The study was conducted under greenhouse (GH) conditions (LD; 16/8 h; ∼20/∼16°C day/night). Genotyping was performed using a genome-wide high density 9K single nucleotide polymorphisms (SNPs) chip which assayed 7842 SNPs. We used the barley physical map to identify candidate genes underlying genome-wide association scans (GWAS). GWAS for pre-anthesis stages/sub-phases in each photoperiod group provided great power for partitioning genetic effects on floral initiation and heading time. In addition to major genes known to regulate heading time under field conditions, several novel QTL with medium to high effects, including new QTL having major effects on developmental stages/sub-phases were found to be associated in this study. For example, highly associated SNPs tagged the physical regions around HvCO1 (barley CONSTANS1) and BFL (BARLEY FLORICAULA/LEAFY) genes. Based upon our GWAS analysis, we propose a new genetic network model for each photoperiod group, which includes several newly identified genes, such as several HvCO-like genes, belonging to different heading time pathways in barley. PMID:25420105

Analysis of roll-stamped light guide plate fabricated with laser-ablated stamper

NASA Astrophysics Data System (ADS)

Na, Hyunjun; Hong, Seokkwan; Kim, Jongsun; Hwang, Jeongho; Joo, Byungyun; Yoon, Kyunghwan; Kang, Jeongjin

2017-12-01

LGP (light guide plate) is one of the major components of LCD (liquid crystal display), and it makes surface illumination for LCD backlit. LGP is a transparent plastic plate usually produced by injection molding process. On the back of LGP there are micron size patterns for extraction of light. Recently a roll-stamping process has achieved the high mass productivity of thinner LGPs. In order to fabricate optical patterns on LGPs, a fabricating tool called as a stamper is used. Micro patterns on metallic stampers are made by several micro machining processes such as chemical etching, LIGA-reflow, and laser ablation. In this study, a roll-stamping process by using a laser ablated metallic stamper was dealt with in consideration of the compatibility with the roll-stamping process. LGP fabricating tests were performed using a roll-stamping process with four different roll pressures. Pattern shapes on the stamper fabricated by laser ablation and transcription ratios of the roll-stamping process were analyzed, and LGP luminance was evaluated. Based on the evaluation, optical simulation model for LGP was made and simulation accuracy was evaluated. Simulation results showed good agreements with optical performance of LGPs in the brightness and uniformity. It was also shown that the roll-stamped LGP has the possibility of better optical performance than the conventional injection molded LGP. It was also shown that the roll-stamped LGP with the laser ablated stamper is potential to have better optical performance than the conventional injection molded LGP.

Engineering a light-activated caspase-3 for precise ablation of neurons in vivo.

PubMed

Smart, Ashley D; Pache, Roland A; Thomsen, Nathan D; Kortemme, Tanja; Davis, Graeme W; Wells, James A

2017-09-26

The circuitry of the brain is characterized by cell heterogeneity, sprawling cellular anatomy, and astonishingly complex patterns of connectivity. Determining how complex neural circuits control behavior is a major challenge that is often approached using surgical, chemical, or transgenic approaches to ablate neurons. However, all these approaches suffer from a lack of precise spatial and temporal control. This drawback would be overcome if cellular ablation could be controlled with light. Cells are naturally and cleanly ablated through apoptosis due to the terminal activation of caspases. Here, we describe the engineering of a light-activated human caspase-3 (Caspase-LOV) by exploiting its natural spring-loaded activation mechanism through rational insertion of the light-sensitive LOV2 domain that expands upon illumination. We apply the light-activated caspase (Caspase-LOV) to study neurodegeneration in larval and adult Drosophila Using the tissue-specific expression system (UAS)-GAL4, we express Caspase-LOV specifically in three neuronal cell types: retinal, sensory, and motor neurons. Illumination of whole flies or specific tissues containing Caspase-LOV-induced cell death and allowed us to follow the time course and sequence of neurodegenerative events. For example, we find that global synchronous activation of caspase-3 drives degeneration with a different time-course and extent in sensory versus motor neurons. We believe the Caspase-LOV tool we engineered will have many other uses for neurobiologists and others for specific temporal and spatial ablation of cells in complex organisms.

Engineering a light-activated caspase-3 for precise ablation of neurons in vivo

PubMed Central

Smart, Ashley D.; Pache, Roland A.; Thomsen, Nathan D.; Kortemme, Tanja; Davis, Graeme W.; Wells, James A.

2017-01-01

The circuitry of the brain is characterized by cell heterogeneity, sprawling cellular anatomy, and astonishingly complex patterns of connectivity. Determining how complex neural circuits control behavior is a major challenge that is often approached using surgical, chemical, or transgenic approaches to ablate neurons. However, all these approaches suffer from a lack of precise spatial and temporal control. This drawback would be overcome if cellular ablation could be controlled with light. Cells are naturally and cleanly ablated through apoptosis due to the terminal activation of caspases. Here, we describe the engineering of a light-activated human caspase-3 (Caspase-LOV) by exploiting its natural spring-loaded activation mechanism through rational insertion of the light-sensitive LOV2 domain that expands upon illumination. We apply the light-activated caspase (Caspase-LOV) to study neurodegeneration in larval and adult Drosophila. Using the tissue-specific expression system (UAS)-GAL4, we express Caspase-LOV specifically in three neuronal cell types: retinal, sensory, and motor neurons. Illumination of whole flies or specific tissues containing Caspase-LOV–induced cell death and allowed us to follow the time course and sequence of neurodegenerative events. For example, we find that global synchronous activation of caspase-3 drives degeneration with a different time-course and extent in sensory versus motor neurons. We believe the Caspase-LOV tool we engineered will have many other uses for neurobiologists and others for specific temporal and spatial ablation of cells in complex organisms. PMID:28893998

A preoperative mathematic model for computed tomographic guided microwave ablation treatment of hepatic dome tumors

PubMed Central

Yang, Bin; Xue, Jing-Bing; Mo, Zhi-Qiang; Zhong, Zhi-Hui; Zhang, Tao; Zhang, Fu-Jun; Fan, Wei-Jun

2016-01-01

Purpose This study sought to prospectively evaluate the feasibility and safety of a preoperative mathematic model for computed tomographic(CT) guided microwave(MW) ablation treatment of hepatic dome tumors. Methods This mathematic model was a regular cylinder quantifying appropriate puncture routes from the bottom up. A total of 103 patients with hepatic dome tumors were enrolled and randomly divided into 2 groups based on whether this model was used or not: Group A (using the model; n = 43) versus Group B (not using the model; n = 60). All tumors were treated by CT-guided MW ablation and follow-up contrast CT were reviewed. Results The average number of times for successful puncture, average ablation time, and incidence of right shoulder pain were less in Group A than Group B (1.4 vs. 2.5, P = 0.001; 8.8 vs. 11.1 minutes, P = 0.003; and 4.7% vs. 20%, P = 0.039). The technical success rate was higher in Group A than Group B (97.7% vs. 85.0%, P = 0.032). There were no significant differences between the two groups in primary and secondary technique efficacy rates (97.7% vs. 88.3%, P = 0.081; 90.0% vs. 72.7%, P = 0.314). No major complications occurred in both groups. Conclusion The mathematic model of regular cylinder is feasible and safe for CT-guided MW ablation in treating hepatic dome tumors. PMID:27028994

Response of cervicogenic headaches and occipital neuralgia to radiofrequency ablation of the C2 dorsal root ganglion and/or third occipital nerve.

PubMed

Hamer, John F; Purath, Traci A

2014-03-01

This article investigates the degree and duration of pain relief from cervicogenic headaches or occipital neuralgia following treatment with radiofrequency ablation of the C2 dorsal root ganglion and/or third occipital nerves. It also addresses the procedure's complication rate and patient's willingness to repeat the procedure if severe symptoms recur. This is a single-center retrospective observational study of 40 patients with refractory cervicogenic headaches and or occipital neuralgia. Patients were all referred by a headache specialty clinic for evaluation for radiofrequency ablation of the C2 dorsal root ganglion and/or third occipital nerves. After treatment, patients were followed for a minimum of 6 months to a year. Patient demographics and the results of radiofrequency ablation were recorded on the same day, after 3-4 days, and at 6 months to 1 year following treatment. Thirty-five percent of patients reported 100% pain relief and 70% reported 80% or greater pain relief. The mean duration of improvement is 22.35 weeks. Complication rate was 12-13%. 92.5% of patients reported they would undergo the procedure again if severe symptoms returned. Radiofrequency ablation of the C2 dorsal root ganglion and/or third occipital nerve can provide many months of greater than 50% pain relief in the vast majority of recipients with an expected length of symptom improvement of 5-6 months. © 2014 American Headache Society.

Meta-analysis of efficacy and safety of apixaban and uninterrupted apixaban therapy compared to vitamin K antagonists in patients undergoing catheter ablation for atrial fibrillation.

PubMed

Ukaigwe, Anene; Shrestha, Pragya; Karmacharya, Paras; Hussain, Sarah K; Samii, Soraya; Gonzalez, Mario D; Wolbrette, Deborah; Naccarrelli, Gerald V

2017-03-01

Apixaban is a Factor Xa inhibitor increasingly being used for stroke prevention in atrial fibrillation (AF). Although several studies have been done, the efficacy and safety of apixaban during the peri-procedural period of AF ablation remains unclear. We sought to systematically review pooled data from these various studies to evaluate thromboembolic and bleeding risks in patients undergoing catheter ablation for AF who are treated with apixaban (interrupted and uninterrupted). Studies comparing anticoagulation with apixaban or vitamin K antagonists (VKA) in patients undergoing ablation for AF were identified via an electronic search of MEDLINE, EMBASE, clinical trials.gov, and Cochrane Library from inception to January 2016. Study-specific risk ratios were calculated and combined with a fixed-effects model meta-analysis. In the analysis of 2100 pooled patients, thromboembolic complications (TE) occurred in 14/778 (1.80 %) patients in the apixaban group (AG) compared to 20/1322 patients in the VKA group (RR 1.03, 95 % CI 0.55-1.90, p = 0.93, I 2  = 0 %). Major bleeding occurred in 9/778 (1.2 %) of the AG compared to 20/1322 (1.51 %) in the VKA group (RR 1.03, 95 % CI 0.55-1.90, p = 0.93, I 2  = 0 %). In uninterrupted apixaban group (uAG), TE occurred in 4/585 (0.68 %) patients in the uAG compared to 6/910 (0.66 %) in VKA group (RR 0.86, 95 % CI 0.25-2.95, p = 0.81, I 2  = 0 %). Major bleeding occurred in 5/585 (0.85 %) in uAG compared to 7/910 (0.77 %) in the VKA group (RR 1.20, 95 % CI 0.37-3.88, p = 0.76, I 2  = 0 %). Our study demonstrates patients treated with apixaban and VKA during the peri-procedural period for AF ablation have similar rates of TE and bleeding complications. Interrupted and uninterrupted apixaban strategies were associated with similar outcomes.

Comparative Effectiveness Review of Cooled Versus Pulsed Radiofrequency Ablation for the Treatment of Knee Osteoarthritis: A Systematic Review.

PubMed

Gupta, Anita; Huettner, Daniel P; Dukewich, Matthew

2017-03-01

Patients suffering from osteoarthritis of the knee and patients post total knee arthroplasty often develop refractory, disabling chronic knee pain. Radiofrequency ablation, including conventional, pulsed, and cooled, has recently become more accepted as an interventional technique to manage chronic knee pain in patients who have failed conservative treatment or who are not suitable candidates for surgical treatment. This systematic review aimed to analyze published studies on radiofrequency ablation to provide an overview of the current knowledge regarding variations in procedures, nerve targets, adverse events, and temporal extent of clinical benefit. A systematic review of published studies investigating conventional, pulsed, or cooled radiofrequency ablation in the setting of chronic knee pain. Medline, Google Scholar, and the Cochrane Central Register of Controlled Trials (CENTRAL) databases were reviewed for studies on radiofrequency ablation for patients with chronic knee pain through July 29, 2016. From the studies, the procedural details, outcomes after treatment, follow-up points, and complications were compiled and analyzed in this literature review. Included studies were analyzed for clinical relevance and strength of evidence was graded using either the NHLBI Quality assessment of controlled intervention studies or the NHLBI quality assessment for before-after (pre-post) studies with no control group. Seventeen total publications were identified in the search, including articles investigating conventional, pulsed, or cooled radiofrequency ablation. These studies primarily targeted either the genicular nerves or used an intraarticular approach. Of the studies, 5 were small-sized randomized controlled trials, although one involved diathermy radiofrequency ablation. There were 8 retrospective or prospective case series and 4 case reports. Utilizing the strength of evidence grading, there is a low level of certainty to suggest a superior benefit between targeting the genicular nerve, an intraarticular approach, or targeting the larger nerves such as femoral and tibial nerves. Utilizing the strength of evidence grading, there is a low level of certainty in supporting the superiority of any specific RFA procedure modality. The majority of the studies report positive patient outcomes, but the inconsistent procedural methodology, inconsistent patient assessment measures, and small study sizes limit the applicability of any specific study to clinical practice. While the wide search strategy included a variety of articles, broad conclusions and pooled data could not be obtained based on the studies analyzed. Overall, the studies showed promising results for the treatment of severe chronic knee pain by radiofrequency ablation at up to one year with minimal complications. Numerous studies, however, yielded concerns about procedural protocols, study quality, and patient follow-up. Radiofrequency ablation can offer substantial clinical and functional benefit to patients with chronic knee pain due to osteoarthritis or post total knee arthroplasty.Key words: Radiofrequency ablation, knee osteoarthritis, knee pain, genicular nerve, total knee arthroplasty (TKA), cooled radiofrequency ablation, pulsed radiofrequency ablation.

A study on the measurement of the core body temperature change after radiofrequency ablation (RFA) through MR temperature mapping

NASA Astrophysics Data System (ADS)

Kim, Chang-Bok; Dong, Kyung-Rae; Yu, Young; Chung, Woon-Kwan; Cho, Jae-Hwan; Joo, Kyu-Ji

2013-09-01

This study examined the change in the heat generated during radiofrequency ablation (RFA) using a self-manufactured phantom and used magnetic resonance imaging (MRI) to analyze the change in the temperature of the core body and the tissues surrounding the phantom. In this experiment, the image and the phase image were obtained simultaneously from a gradient echo-based sequence using 1.5-Tesla MRI equipment and a 12-channel head coil. The temperature mapping technique was used to calculate the change in temperature. The regions of interest (ROIs) (ROI 1 - ROI 6) were set with a focus on the area where the RFA was performed, according to the temperature distribution, before monitoring the temperature change for one hour in time intervals of five minutes. The results showed that the temperature change in the ROI with time was largest in the ROI 1 and smallest in the ROI 5. In addition, after the RFA procedure, the temperature decreased from the initial value to 0 °C in one hour. The temperature changes in the core body and the surrounding tissues were confirmed by MRI temperature mapping, which is a noninvasive method.

Experimental analysis of SiC-based refractory concrete in hybrid rocket nozzles

NASA Astrophysics Data System (ADS)

D'Elia, Raffaele; Bernhart, Gérard; Hijlkema, Jouke; Cutard, Thierry

2016-09-01

Hybrid propulsion represents a good alternative to the more widely used liquid and solid systems. This technology combines some important specifications of the latters, as the possibility of re-ignition, thrust modulation, a higher specific impulse than solid systems, a greater simplicity and a lower cost than liquid systems. Nevertheless the highly oxidizing environment represents a major problem as regards the thermo-oxidation and ablative behavior of nozzle materials. The main goal of this research is to characterize a silicon carbide based micro-concrete with a maximum aggregates size of 800 μm, in a hybrid propulsion environment. The nozzle throat has to resist to a highly oxidizing polyethylene/nitrous oxide hybrid environment, under temperatures up to 2900 K. Three tests were performed on concrete-based nozzles in HERA Hybrid Rocket Motor (HRM) test bench at ONERA. Pressure chamber evolution and observations before and after tests are used to investigate the ablated surface at nozzle throat. Ablation behavior and crack generation are discussed and some improvements are proposed.

MRI-Guided Focused Ultrasound Surgery

PubMed Central

Jolesz, Ferenc A.

2014-01-01

MRI-guided focused ultrasound (MRgFUS) surgery is a noninvasive thermal ablation method that uses magnetic resonance imaging (MRI) for target definition, treatment planning, and closed-loop control of energy deposition. Integrating FUS and MRI as a therapy delivery system allows us to localize, target, and monitor in real time, and thus to ablate targeted tissue without damaging normal structures. This precision makes MRgFUS an attractive alternative to surgical resection or radiation therapy of benign and malignant tumors. Already approved for the treatment of uterine fibroids, MRgFUS is in ongoing clinical trials for the treatment of breast, liver, prostate, and brain cancer and for the palliation of pain in bone metastasis. In addition to thermal ablation, FUS, with or without the use of microbubbles, can temporarily change vascular or cell membrane permeability and release or activate various compounds for targeted drug delivery or gene therapy. A disruptive technology, MRgFUS provides new therapeutic approaches and may cause major changes in patient management and several medical disciplines. PMID:19630579

Oxidation of laser-induced plasma species in different background conditions

NASA Astrophysics Data System (ADS)

Bator, Matthias; Schneider, Christof W.; Lippert, Thomas; Wokaun, Alexander

2013-08-01

The evolution of Lu and LuO species in a laser ablation plasma from different targets has been investigated by simultaneously performing mass spectrometry and plasma imaging. Ablation was achieved with a 248 nm KrF laser from a Lu, a Lu2O5 and a LuMnO3 target under different background gas conditions. Mass spectrometry measurements show very similar intensities and ratios for the respective species for all three targets under the same ablation conditions. This indicates only a small influence of the target on the final Lu and LuO contents in the plasma, with the major influence coming from collisions with the background gas. Furthermore, spatially, timely and spectrally resolved plasma imaging was utilized to clearly identify the shockwave at the plasma front as the main region for Lu oxidation. A strong decrease of Lu intensities together with a directly correlated increase of LuO was observed toward the outer regions of the plasma.

NIMH's TADS: More than Just a Tad of Progress?

ERIC Educational Resources Information Center

Jensen, Peter S.

2005-01-01

The Treatment for Adolescents With Depression Study (TADS) derives substantial public health significance from its head-to-head comparisons of carefully administered medication versus a carefully crafted cognitive-behavioral therapy in youth with major depression, the first major clinical trial of its kind. Although the study has a number of…

Recommended minimal cockpit head motion box dimensions

DOT National Transportation Integrated Search

2001-09-26

This memo provides recommendations for the dimensions of the minimal CHMB based on a study of pilot head motion in actual flight. These recommended dimensions should accommodate the vast majority of the targeted head motion exhibited by the vast majo...

The quest for durable lesions in catheter ablation of atrial fibrillation - technological advances in radiofrequency catheters and balloon devices.

PubMed

Maurer, Tilman; Kuck, Karl-Heinz

2017-08-01

Atrial fibrillation is the most common cardiac arrhythmia and represents a growing clinical, social and economic challenge. Catheter ablation for symptomatic atrial fibrillation has evolved from an experimental procedure into a widespread therapy and offers a safe and effective treatment option. A prerequisite for durable PVI are transmural and contiguous circumferential lesions around the pulmonary veins. However, electrical reconnection of initially isolated pulmonary veins remains a primary concern and is a dominant factor for arrhythmia recurrence during long-term follow up. Areas covered: This article discusses the physiology of lesion formation using radiofrequency-, cryo- or laser- energy for pulmonary vein isolation and provides a detailed review of recent technological advancements in the field of radiofrequency catheters and balloon devices. Finally, future directions and upcoming developments for the interventional treatment of atrial fibrillation are discussed. Expert commentary: Durable conduction block across deployed myocardial lesions is mandatory not only for PVI but for any other cardiac ablation strategy as well. A major improvement urgently expected is the intraprocedural real-time distinction of durable lesions from interposed gaps with only transiently impaired electrical conduction. Furthermore, a simplification of ablation tools used for PVI is required to reduce the high technical complexity of the procedure.

Tandem Laser Induced Breakdown Spectroscopy (LIBS), Laser Ablation Inductively Coupled Plasma Mass Spectroscopy (LA-ICP-MS) and/or Laser Ablation Inductively Coupled Plasma Optical Emission Spectroscopy (LA-ICP-OES) for the analysis of samples of geological interest

NASA Astrophysics Data System (ADS)

Oropeza, D.

2016-12-01

A highly innovative laser ablation sampling instrument (J200 Tandem LA - LIBS) that combines the capabilities and analytical benefits of LIBS, LA-ICP-MS and LA-ICP-OES was used for micrometer-scale, spatially-resolved, elemental analysis of a wide variety of samples of geological interest. Data collected using ablation systems consisted of nanosecond (Nd:YAG operated 266nm) and femtosecond lasers (1030 and 343nm). An ICCD LIBS detector and Quadrupole based mass spectrometer were selected for LIBS and ICP-MS detection, respectively. This tandem instrument allows simultaneous determination of major and minor elements (for example, Si, Ca, Na, and Al, and trace elements such as Li, Ce, Cr, Sr, Y, Zn, Zr among others). The research also focused on elemental mapping and calibration strategies, specifically the use of emission and mass spectra for multivariate data analysis. Partial Least Square Regression (PLSR) is shown to minimize and compensate for matrix effects in the emission and mass spectra improving quantitative analysis by LIBS and LA-ICP-MS, respectively. The study provides a benchmark to evaluate analytical results for more complex geological sample matrices.

Pathology of non-thermal irreversible electroporation (N-TIRE)-induced ablation of the canine brain.

PubMed

Rossmeisl, John H; Garcia, Paulo A; Roberston, John L; Ellis, Thomas L; Davalos, Rafael V

2013-01-01

This study describes the neuropathologic features of normal canine brain ablated with non-thermal irreversible electroporation (N-TIRE). The parietal cerebral cortices of four dogs were treated with N-TIRE using a dose-escalation protocol with an additional dog receiving sham treatment. Animals were allowed to recover following N-TIRE ablation and the effects of treatment were monitored with clinical and magnetic resonance imaging examinations. Brains were subjected to histopathologic and ultrastructural assessment along with Bcl-2, caspase-3, and caspase-9 immunohistochemical staining following sacrifice 72 h post-treatment. Adverse clinical effects of N-TIRE were only observed in the dog treated at the upper energy tier. MRI and neuropathologic examinations indicated that N-TIRE ablation resulted in focal regions of severe cytoarchitectural and blood-brain-barrier disruption. Lesion size correlated to the intensity of the applied electrical field. N-TIRE-induced lesions were characterized by parenchymal necrosis and hemorrhage; however, large blood vessels were preserved. A transition zone containing parenchymal edema, perivascular inflammatory cuffs, and reactive gliosis was interspersed between the necrotic focus and normal neuropil. Apoptotic labeling indices were not different between the N-TIRE-treated and control brains. This study identified N-TIRE pulse parameters that can be used to safely create circumscribed foci of brain necrosis while selectively preserving major vascular structures.

Computed Tomographic Angiographic Perforator Localization for Virtual Surgical Planning of Osteocutaneous Fibular Free Flaps in Head and Neck Reconstruction.

PubMed

Ettinger, Kyle S; Alexander, Amy E; Arce, Kevin

2018-04-10

Virtual surgical planning (VSP), computer-aided design and computer-aided modeling, and 3-dimensional printing are 3 distinct technologies that have become increasingly used in head and neck oncology and microvascular reconstruction. Although each of these technologies has long been used for treatment planning in other surgical disciplines, such as craniofacial surgery, trauma surgery, temporomandibular joint surgery, and orthognathic surgery, its widespread use in head and neck reconstructive surgery remains a much more recent event. In response to the growing trend of VSP being used for the planning of fibular free flaps in head and neck reconstruction, some surgeons have questioned the technology's implementation based on its inadequacy in addressing other reconstructive considerations beyond hard tissue anatomy. Detractors of VSP for head and neck reconstruction highlight its lack of capability in accounting for multiple reconstructive factors, such as recipient vessel selection, vascular pedicle reach, need for dead space obliteration, and skin paddle perforator location. It is with this premise in mind that the authors report on a straightforward technique for anatomically localizing peroneal artery perforators during VSP for osteocutaneous fibular free flaps in which bone and a soft tissue skin paddle are required for ablative reconstruction. The technique allows for anatomic perforator localization during the VSP session based solely on data existent at preoperative computed tomographic angiography (CTA); it does not require any modifications to preoperative clinical workflows. It is the authors' presumption that many surgeons in the field are unaware of this planning capability within the context of modern VSP for head and neck reconstruction. The primary purpose of this report is to introduce and further familiarize surgeons with the technique of CTA perforator localization as a method of improving intraoperative fidelity for VSP of osteocutaneous fibular free flaps. Copyright © 2018. Published by Elsevier Inc.

Major uncertainties influencing entry probe heat shield design

NASA Technical Reports Server (NTRS)

Congdon, W.

1974-01-01

Factors influencing the design of an outer planet probe heat shield are discussed. Major factors included are: uncertainties in composition and scale height of the planet atmospheres; the augmentation/attenuation of entry heating by ablation products requires more computer study and testing; carbon heat shields, especially carbon phenolic, possessing improved resistance to spallation need developing; and white silica reflecting heat shields with improved resistance to bulk vitrification need further developing.

Mortality prediction of head Abbreviated Injury Score and Glasgow Coma Scale: analysis of 7,764 head injuries.

PubMed

Demetriades, Demetrios; Kuncir, Eric; Murray, James; Velmahos, George C; Rhee, Peter; Chan, Linda

2004-08-01

We assessed the prognostic value and limitations of Glasgow Coma Scale (GCS) and head Abbreviated Injury Score (AIS) and correlated head AIS with GCS. We studied 7,764 patients with head injuries. Bivariate analysis was performed to examine the relationship of GCS, head AIS, age, gender, and mechanism of injury with mortality. Stepwise logistic regression analysis was used to identify the independent risk factors associated with mortality. The overall mortality in the group of head injury patients with no other major extracranial injuries and no hypotension on admission was 9.3%. Logistic regression analysis identified head AIS, GCS, age, and mechanism of injury as significant independent risk factors of death. The prognostic value of GCS and head AIS was significantly affected by the mechanism of injury and the age of the patient. Patients with similar GCS or head AIS but different mechanisms of injury or ages had significantly different outcomes. The adjusted odds ratio of death in penetrating trauma was 5.2 (3.9, 7.0), p < 0.0001, and in the age group > or = 55 years the adjusted odds ratio was 3.4 (2.6, 4.6), p < 0.0001. There was no correlation between head AIS and GCS (correlation coefficient -0.31). Mechanism of injury and age have a major effect in the predictive value of GCS and head AIS. There is no good correlation between GCS and head AIS.

The Effects of Head Start Health Services: Executive Summary of the Head Start Health Evaluation.

ERIC Educational Resources Information Center

Fosburg, Linda B.; And Others

This report summarizes findings of an evaluation of Head Start health services. Chapter one presents an overview of the background of the evaluation project. Chapter two highlights findings for the major evaluation questions. These questions focus specifically on children's health status prior to entry into Head Start, health services subsequently…

Safety and efficacy of switching anticoagulation to aspirin three months after successful radiofrequency catheter ablation of atrial fibrillation.

PubMed

Uhm, Jae-Sun; Won, Hoyoun; Joung, Boyoung; Nam, Gi-Byoung; Choi, Kee-Joon; Lee, Moon-Hyoung; Kim, You-Ho; Pak, Hui-Nam

2014-09-01

Although current guidelines recommend continuing the same antithrombotic strategy regardless of rhythm control after radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF), anticoagulation has a risk of major bleeding. We evaluated the safety of switching warfarin to aspirin in patients with successful AF ablation. Among 721 patients who underwent RFCA of AF, 608 patients (age, 57.3±10.9 years; 77.0% male, 75.5% paroxysmal AF) who had no evidence of AF recurrence at 3 months post-RFCA were included. We compared the thromboembolic and hemorrhagic events in patients for whom warfarin was switched to aspirin (ASA group; n=296) and patients who were kept on warfarin therapy (W group; n=312). There were no significant differences in CHA₂DS₂-VASc or HAS-BLED scores between the groups. In 30 patients in the ASA group and 37 patients in W group, AF recurred and warfarin was restarted or maintained during the 18.0±12.2 months of follow-up. There were no significant differences in thromboembolic (0.3% vs. 1.0%, p=0.342) and major bleeding incidences (0.7% vs. 0.6%, p=0.958) between ASA and W groups during the follow-up period. In the 259 patients with a CHA₂DS₂-VASc score≥2, there were no significant differences in thromboembolism (0.8% and 2.2%, p=0.380) or major bleeding incidences (0.8% and 1.4%, p=0.640) between ASA and W groups. Switching warfarin to aspirin 3 months after successful RFCA of AF could be as safe and efficacious as long-term anticoagulation even in patients with CHA₂DS₂-VASc score≥2. However, strict rhythm monitoring cannot be overemphasized.

Pulmonary Vein Isolation with the Cryoballoon Technique: Feasibility, Procedural Outcomes, and Adoption in the Real World: Data from One Shot Technologies TO Pulmonary Vein Isolation (1STOP) Project.

PubMed

Padeletti, Luigi; Curnis, Antonio; Tondo, Claudio; Lunati, Maurizio; Porcellini, Stefano; Verlato, Roberto; Sciarra, Luigi; Senatore, Gaetano; Catanzariti, Domenico; Leoni, Loira; Landolina, Maurizio; Delise, Pietro; Iacopino, Saverio; Pieragnoli, Paolo; Arena, Giuseppe

2017-01-01

Catheter ablation (CA) is recommended for patients with drug refractory symptomatic atrial fibrillation (AF). "One Shot" catheters have been introduced to simplify CA and cryoballoon ablation (CBA) is spreading rapidly. Few real-world data are available on standard clinical practice, mainly from single-center experience. We aimed to evaluate clinical settings, demographics, and acute procedural outcomes in a large cohort of patients treated with CBA. A total of 903 patients (73% male, mean age 59 ± 11) underwent pulmonary vein CBA. Correlations between the patient's inclusion time and clinical characteristics, procedure duration, acute success rate, and intraprocedural complications were evaluated. Seventy-seven percent of patients were affected by paroxysmal AF and 23% by persistent AF. Overall, acute success rate was 97.9% and periprocedural complications were observed in 35 (3.9%) patients, 13 (1.4%) of which were classified as major complications. With respect to the patient's inclusion time analysis, an increase in treatment of persistent AF was observed, a significant decrease in CBA times (procedure, ablation, and fluoroscopy: 136.0 ± 46.5 minutes, 28.8 ± 19.6 minutes, and 34.3 ± 15.4 minutes, respectively) was observed, with comparable acute success rate and intraprocedural complications over time. The rate of major complications was extremely low (1.4%); no death, atrioesophageal fistula, stroke, or other major periinterventional or late complications occurred. This series represents the largest experience of CBA in the treatment of AF that also describes the adoption curve of this relatively recent technology. CBA showed an excellent safety profile when performed in a large real-world clinical setting, with satisfactory acute success rate and, on average, short procedural times. clinicaltrials.gov (NCT01007474). © 2016 Wiley Periodicals, Inc.

Ablation for Atrial Fibrillation

PubMed Central

2006-01-01

Executive Summary Objective To review the effectiveness, safety, and costing of ablation methods to manage atrial fibrillation (AF). The ablation methods reviewed were catheter ablation and surgical ablation. Clinical Need Atrial fibrillation is characterized by an irregular, usually rapid, heart rate that limits the ability of the atria to pump blood effectively to the ventricles. Atrial fibrillation can be a primary diagnosis or it may be associated with other diseases, such as high blood pressure, abnormal heart muscle function, chronic lung diseases, and coronary heart disease. The most common symptom of AF is palpitations. Symptoms caused by decreased blood flow include dizziness, fatigue, and shortness of breath. Some patients with AF do not experience any symptoms. According to United States data, the incidence of AF increases with age, with a prevalence of 1 per 200 people aged between 50 and 60 years, and 1 per 10 people aged over 80 years. In 2004, the Institute for Clinical Evaluative Sciences (ICES) estimated that the rate of hospitalization for AF in Canada was 582.7 per 100,000 population. They also reported that of the patients discharged alive, 2.7% were readmitted within 1 year for stroke. One United States prevalence study of AF indicated that the overall prevalence of AF was 0.95%. When the results of this study were extrapolated to the population of Ontario, the prevalence of AF in Ontario is 98,758 for residents aged over 20 years. Currently, the first-line therapy for AF is medical therapy with antiarrhythmic drugs (AADs). There are several AADs available, because there is no one AAD that is effective for all patients. The AADs have critical adverse effects that can aggravate existing arrhythmias. The drug selection process frequently involves trial and error until the patient’s symptoms subside. The Technology Ablation has been frequently described as a “cure” for AF, compared with drug therapy, which controls AF but does not cure it. Ablation involves directing an energy source at cardiac tissue. For instance, radiofrequency energy uses heat to burn tissue near the source of the arrhythmia. The purpose is to create a series of scar tissue, so that the aberrant electrical pathways can no longer exist. Because the pulmonary veins are the predominant source of AF initiation, the primary goal of ablation is to isolate the pulmonary veins from the left atria through the creation of a conduction block. There are 2 methods of ablation: catheter ablation and surgical (operative) ablation. Radiofrequency energy is most commonly used for ablation. Catheter ablation involves inserting a catheter through the femoral vein to access the heart and burn abnormal foci of electrical activity by direct contact or by isolating them from the rest of the atrium. The surgical ablation is performed minimally invasively via direct visualization or with the assistance of a special scope for patients with lone AF. Review Strategy In March 2006, the following databases were searched: Cochrane Library International Agency for Health Technology Assessment (first quarter 2006), Cochrane Database of Systematic Reviews (first quarter 2006), Cochrane Central Register of Controlled Trials (first quarter 2006), MEDLINE (1966 to February 2006), MEDLINE In-Process and Other Non-indexed Citations (1966 to March 1, 2006), and EMBASE (1980 to 2006 week 9). The Medical Advisory Secretariat also searched Medscape on the Internet for recent reports on trials that were unpublished but that were presented at international conferences. In addition, the Web site Current Controlled Trials (www.controlled-trials.com) was searched for ongoing trials investigating ablation for atrial fibrillation. Search terms included: radiofrequency ablation, catheter ablation and atrial fibrillation. Summary of Findings Sixteen RCTs were identified that compared ablation methods in patients with AF. Two studies were identified that investigated first-line therapy for AF or atrial flutter. Seven other studies examined patients with drug-refractory, lone AF; and the remaining 7 RCTs compared ablation plus heart surgery to heart surgery alone in patients with drug-refractory AF and concomitant heart conditions. First-line Catheter Ablation for Atrial Fibrillation or Atrial Flutter Both studies concluded that catheter ablation was associated with significantly improved long-term freedom from arrhythmias and quality of life compared with medical therapy. These studies included different patient populations (those with AF in one pilot study, and those with atrial flutter in the other). Catheter ablation as first-line treatment is considered experimental at this time. Catheter Ablation Versus Medical Therapy in Patients With Drug-Refractory, Lone Atrial Fibrillation In this review, catheter ablation had success rates (freedom from arrhythmia) that ranged from 42% to 90% (median, 74%) in patients with drug-refractory, lone AF. All 3 of the RCTs comparing catheter ablation to medical therapy in patients with drug-refractory, lone AF found a significant improvement in terms of freedom from arrhythmia over a minimum of 12 months follow-up (P<.05). Ablation Plus Heart Surgery Versus Heart Surgery Alone in Patients With Atrial Fibrillation It is clear that patients with drug-refractory AF who are undergoing concomitant heart surgery (usually mitral valve repair or replacement) benefit significantly from surgical ablation, in terms of long-term freedom from AF, without substantial additional risk compared to open heart surgery alone. This group of patients represents about 1% of the patients with atrial fibrillation, thus the majority of the burden of AF lies within the patients with lone AF (i.e. those not requiring additional heart surgery). Conclusion Catheter ablation appears to be an effective treatment for patients with drug-refractory AF whose treatment alternatives are limited. Ablation technology is continually evolving with increasing success rates associated with the ablation procedure. PMID:23074498

Lessons Learned from Unfavorable Microsurgical Head and Neck Reconstruction: Japan National Cancer Center Hospital and Okayama University Hospital.

PubMed

Kimata, Yoshihiro; Matsumoto, Hiroshi; Sugiyama, Narusi; Onoda, Satoshi; Sakuraba, Minoru

2016-10-01

The risk of surgical site infection (SSI) remains high after major reconstructive surgery of the head and neck. Clinical data regarding SSI in microsurgical tongue reconstruction are described at National Cancer Hospital in Japan, including discussions of unfavorable representative cases, the relationship between SSI and preoperative irradiation at Okayama University Hospital in Japan, and strategies for SSI control in head and neck reconstruction. Local complications are inevitable in patients undergoing reconstruction in the head and neck areas. The frequency of major complications can be decreased, and late postoperative complications can be prevented with the help of appropriate methods. Copyright © 2016 Elsevier Inc. All rights reserved.

Renal denervation using catheter-based radiofrequency ablation with temperature control: renovascular safety profile and underlying mechanisms in a hypertensive canine model.

PubMed

Li, Huijie; Yu, Hang; Zeng, Chunyu; Fang, Yuqiang; He, Duofen; Zhang, Xiaoqun; Wen, Chunlan; Yang, Chengming

2015-01-01

Renal denervation is a novel method for hypertension treatment. In this study, we aimed to investigate the safety and efficacy of radiofrequency ablation (RFA) at ablation temperatures of 45 °C or 50 °C and its possible mechanisms. A hypertensive canine model was established by abdominal aortic constriction in 20 healthy hybrid dogs. These dogs were then randomly assigned to the treatment and the control groups, with dogs in the treatment group further randomly assigned to receive RFA at ablation temperatures of 45 °C or 50 °C. In the treatment group, RFA was performed at 1 month after modeling; renal angiography was performed at 2 months after ablation. The arterial vessels of the dogs were examined histologically with hematoxylin and eosin staining. Changes in blood pressure in the foreleg and whole-body norepinephrine spillover rate were also assessed. No arterial stenosis, dissection, thrombosis or other abnormalities were detected in the treated vessels by renal angiography, yet histology results showed minimal to mild renal arterial injury. Renal denervation resulted in a marked decrease in the whole-body norepinephrine spillover rate (p < 0.05) in addition to significantly reducing blood pressure (p < 0.05), with no significant differences detected between the 45 °C and 50 °C subgroups for both (p > 0.05). Renal denervation can be performed without acute major adverse events, using catheter-based RFA with temperature control. The procedure was feasible in reducing blood pressure by at least partially inhibiting sympathetic drive and systemic sympathetic outflow.

Mapping of the left-sided phrenic nerve course in patients undergoing left atrial catheter ablations.

PubMed

Huemer, Martin; Wutzler, Alexander; Parwani, Abdul S; Attanasio, Philipp; Haverkamp, Wilhelm; Boldt, Leif-Hendrik

2014-09-01

Catheter ablation of atrial fibrillation has been associated with left-sided phrenic nerve palsy. Knowledge of the individual left phrenic nerve course therefore is essential to prevent nerve injury. The aim of this study was to test the feasibility of an intraprocedural pace mapping and reconstruction of the left phrenic nerve course and to characterize which anatomical areas are affected. In patients undergoing left atrial catheter ablation, a three-dimensional map of the left atrial anatomical structures was created. The left-sided phrenic nerve course was determined by high-output pace mapping and reconstructed in the map. In this study, 40 patients with atrial fibrillation or atrial tachycardias were included. Left phrenic nerve capture was observed in 23 (57.5%) patients. Phrenic nerve was captured in 22 (55%) patients inside the left atrial appendage, in 22 (55%) in distal parts, in 21 (53%) in medial parts, and in two (5%) in ostial parts of the appendage. In three (7.5%) patients, capture was found in the distal coronary sinus and in one (2.5%) patient in the left atrium near the left atrial appendage ostium. Ablation target was changed due to direct spatial relationship to the phrenic nerve in three (7.5%) patients. No phrenic nerve palsy was observed. Left-sided phrenic nerve capture was found inside and around the left atrial appendage in the majority of patients and additionally in the distal coronary sinus. Phrenic nerve mapping and reconstruction can easily be performed and should be considered prior catheter ablations in potential affected areas. ©2014 Wiley Periodicals, Inc.

Renal Tumors: Technical Success and Early Clinical Experience with Radiofrequency Ablation of 18 Tumors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sabharwal, Rohan, E-mail: rohan50000@yahoo.com; Vladica, Philip

2006-04-15

Purpose. To evaluate the feasibility, safety, and technical efficacy of image-guided radiofrequency ablation (RFA) for the treatment of small peripheral renal tumors and to report our early results with this treatment modality. Methods. Twenty-two RFA sessions for 18 tumors were performed in 11 patients with renal tumors. Indications included coexistent morbidity, high surgical or anesthetic risk, solitary kidney, and hereditary predisposition to renal cell carcinoma. Ten patients had CT-guided percutaneous RFA performed on an outpatient basis. One patient had open intraoperative ultrasound-guided RFA. Technical success was defined as elimination of areas that enhanced at imaging within the entire tumor. Withmore » the exception of one patient with renal insufficiency who required gadolinium-enhanced MRI, the remaining patients underwent contrast-enhanced CT for post-treatment follow-up assessment. Follow-up was performed after 2-4 weeks and then at 3, 6, 12 months, and every 12 months thereafter. Results. Fourteen (78%) of 18 tumors were successfully ablated with one session. Three of the remaining four tumors required two sessions for successful ablation. One tumor will require a third session for areas of persistent enhancement. Mean patient age was 72.82 {+-} 10.43 years. Mean tumor size was 1.95 {+-} 0.79 cm. Mean follow-up time was 10.91 months. All procedures were performed without any major complications. Conclusions. Our early experience with percutaneous image-guided radiofrequency ablation demonstrates it to be a feasible, safe, noninvasive, and effective treatment of small peripheral renal tumors.« less

Impact of obesity on atrial fibrillation ablation: Patient characteristics, long-term outcomes, and complications.

PubMed

Winkle, Roger A; Mead, R Hardwin; Engel, Gregory; Kong, Melissa H; Fleming, William; Salcedo, Jonathan; Patrawala, Rob A

2017-06-01

There is an association between obesity and atrial fibrillation (AF). The impact of obesity on AF ablation procedures is unclear. The purpose of this study was to evaluate the influence of body mass index (BMI) on patient characteristics, long-term ablation outcomes, and procedural complications. We evaluated 2715 patients undergoing 3742 AF ablation procedures. BMI was ≥30 kg/m 2 in 1058 (39%) and ≥40 kg/m 2 in 129 (4.8%). Patients were grouped by BMI ranges (<25, 25-<30, 30-<35, 35-<40, and ≥40 kg/m 2 ). As BMI increased from <25 to ≥40 kg/m 2 , age decreased from 65.3 ± 11.2 to 61.2 ± 9.2 years (P < .001), left atrial size increased from 3.91 ± 0.68 to 4.72 ± 0.62 cm (P < .005), and CHADS 2 scores increased from 1.24 ± 1.10 to 1.62 ± 1.09 (P < .001). As BMI increased, paroxysmal AF decreased from 48.0% to 16.3% (P < .0001) and there was an increase in dilated cardiomyopathy (from 7.6% to 12.4%; P < .0001), hypertension (from 41.0% to 72.9%; P < .0001), diabetes (from 4.3% to 23.3%; P < .0001), and sleep apnea (from 7.0% to 46.9%; P < .0001). For the entire cohort, for BMI ≥35 kg/m 2 the 5-year ablation freedom from AF decreased from 67%-72% to 57% (P = .036). For paroxysmal AF, when BMI was ≥40 kg/m 2 ablation success decreased from 79%-82% to 60% (P = .064), and for persistent AF, when BMI was ≥35 kg/m 2 ablation success decreased from 64%-70% to 52%-57% (P = .021). For long-standing AF, there was no impact of BMI on outcomes (P = .624). In multivariate analysis, BMI ≥35 kg/m 2 predicted worse outcomes (P = .036). Higher BMI did not impact major complication rates (P = .336). However, when BMI was ≥40 kg/m 2 , minor (from 2.1% to 4.4%; P = .035) and total (from 3.5% to 6.7%; P = .023) complications increased. In patients undergoing AF ablation, increasing BMI is associated with more patient comorbidities and more persistent and long-standing AF. BMI ≥35 kg/m 2 adversely impacts ablation outcomes, and BMI ≥40 kg/m 2 increases minor complications. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Investigations of the Cavitation and Damage Thresholds of Histotripsy and Applications in Targeted Tissue Ablation

NASA Astrophysics Data System (ADS)

Vlaisavljevich, Eli

Histotripsy is a noninvasive ultrasound therapy that controls acoustic cavitation to mechanically fractionate soft tissue. This dissertation investigates the physical thresholds to initiate cavitation and produce tissue damage in histotripsy and factors affecting these thresholds in order to develop novel strategies for targeted tissue ablation. In the first part of this dissertation, the effects of tissue properties on histotripsy cavitation thresholds and damage thresholds were investigated. Results demonstrated that the histotripsy shock scattering threshold using multi-cycle pulses increases in stiffer tissues, while the histotripsy intrinsic threshold using single-cycle pulses is independent of tissue stiffness. Further, the intrinsic threshold slightly decreases with lower frequencies and significantly decreases with increasing temperature. The effects of tissue properties on the susceptibility to histotripsy-induced tissue damage were also investigated, demonstrating that stiffer tissues are more resistant to histotripsy. Two strategies were investigated for increasing the effectiveness of histotripsy for the treatment of stiffer tissues, with results showing that thermal preconditioning may be used to alter tissue susceptibility to histotripsy and that lower frequency treatments may increase the efficiency of histotripsy tissue ablation due to enhanced bubble expansion. In the second part of this dissertation, the feasibility of using histotripsy for targeted liver ablation was investigated in an intact in vivo porcine model, with results demonstrating that histotripsy was capable of non-invasively creating precise lesions throughout the entire liver. Additionally, a tissue selective ablation approach was developed, where histotripsy completely fractionated the liver tissue surrounding the major hepatic vessels and gallbladder while being self-limited at the boundaries of these critical structures. Finally, the long-term effects of histotripsy liver ablation were investigated in an intact in vivo rodent model, showing that the liver homogenate resulting from histotripsy-induced tissue fractionation was completely resorbed over the course of 28 days. In the final part of this dissertation, a novel ablation method combining histotripsy with acoustically sensitive nanodroplets was developed for targeted cancer cell ablation, demonstrating the potential of using nanodroplet-mediated histotripsy (NMH) for targeted, multi-focal ablation. Studies demonstrated that lower frequency and higher boiling point perfluorocarbon droplets can improve NMH therapy. The role of positive and negative pressure on cavitation nucleation in NMH was also investigated, showing that NMH cavitation nucleation is caused directly from the peak negative pressure of the incident wave, similar to histotripsy bubbles generated above the intrinsic threshold. Overall, the results of this dissertation provide significant insight into the physical mechanisms underlying histotripsy tissue ablation and will help to guide the future development of histotripsy for clinical applications such as the treatment of liver cancer.

Laser-induced thermal ablation of cancerous cell organelles.

PubMed

Letfullin, Renat R; Szatkowski, Scott A

2017-07-01

By exploiting the physical changes experienced by cancerous organelles, we investigate the feasibility of destroying cancerous cells by single and multipulse modes of laser heating. Our procedure consists of two primary steps: determining the normal and cancerous organelles optical properties and simulating the heating of all of the major organelles in the cell to find the treatment modes for the laser ablation of cancerous organelles without harming healthy cells. Our simulations show that the cancerous nucleus can be selectively heated to damaging temperatures, making this nucleus a feasible therapeutic particle and removing the need for nanoparticle injection. Because of the removal of this extra step, the procedure we propose is simpler and safer for the patient.

An Autopsy Case of a Pregnant Woman With Severe Placental and Fetal Damage From Domestic Violence.

PubMed

Kanawaku, Yoshimasa; Takahashi, Shirushi; Kanetake, Jun; Funayama, Masato

2015-09-01

We present an autopsy case of a pregnant woman who was a victim of domestic violence. The deceased showed injuries mainly to her head and abdomen. Postmortem examination revealed 1400 mL of abdominal hemorrhage, ablation of the perimetrium, placental avulsion, and intracranial hematoma. The cause of death was diagnosed as hemorrhagic shock. The uterus contained a fetus of 7 months' gestational age. Fetal autopsy revealed laceration of the lungs, laceration and avulsion of the liver, and 15 mL of hemoperitoneum. Both placental and fetal injuries suggested repeated severe attacks to the abdomen, such as those expected to result from kicking or hitting.

Maxillofacial prosthodontic rehabilitation of a patient with oral complications during and after multimodality therapy for the management of oral squamous cell carcinoma.

PubMed

Acharya, Varun; Chambers, Mark S

2015-06-01

Multimodality cancer therapy involving surgical resection, chemotherapy, and radiation therapy is frequently employed in the management of head and neck cancer. Patients who have undergone such therapy face substantial challenges during and after treatment. Prosthodontic rehabilitation is essential during and after tumor ablation to restore function, esthetics, and minimize interruption in daily routine. This clinical report describes the challenges faced by a patient undergoing multimodality therapy for a squamous cell carcinoma of the maxillary sinus and the stages involved in prosthodontic rehabilitation. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

A Bibliography: 1964-1967. Supplement

DTIC Science & Technology

1969-01-01

General Hubert R. Harmon, 1954-1956 Major General James E. Briggs, 1956-1959 Major General William S. Stone, 1959-1962 Major General Robert H...Professor and Head, Dept pf Mathematics) 62498 17Jul 63 1 Aug 62 Col Marcos E. Kinevan (Professor and Head, Dept of Law) 17625 20Nov 64 lOJul 67 1...175, 186 housing, 175 Howard, Michael, 283 Hruska, Roman L. , 50, 107 humanities, 129 Hubbell, John G. , 215 Humphrey, Hubert H

Deletion of OTX2 in neural ectoderm delays anterior pituitary development

PubMed Central

Mortensen, Amanda H.; Schade, Vanessa; Lamonerie, Thomas; Camper, Sally A.

2015-01-01

OTX2 is a homeodomain transcription factor that is necessary for normal head development in mouse and man. Heterozygosity for loss-of-function alleles causes an incompletely penetrant, haploinsufficiency disorder. Affected individuals exhibit a spectrum of features that range from developmental defects in eye and/or pituitary development to acephaly. To investigate the mechanism underlying the pituitary defects, we used different cre lines to inactivate Otx2 in early head development and in the prospective anterior and posterior lobes. Mice homozygous for Otx2 deficiency in early head development and pituitary oral ectoderm exhibit craniofacial defects and pituitary gland dysmorphology, but normal pituitary cell specification. The morphological defects mimic those observed in humans and mice with OTX2 heterozygous mutations. Mice homozygous for Otx2 deficiency in the pituitary neural ectoderm exhibited altered patterning of gene expression and ablation of FGF signaling. The posterior pituitary lobe and stalk, which normally arise from neural ectoderm, were extremely hypoplastic. Otx2 expression was intact in Rathke's pouch, the precursor to the anterior lobe, but the anterior lobe was hypoplastic. The lack of FGF signaling from the neural ectoderm was sufficient to impair anterior lobe growth, but not the differentiation of hormone-producing cells. This study demonstrates that Otx2 expression in the neural ectoderm is important intrinsically for the development of the posterior lobe and pituitary stalk, and it has significant extrinsic effects on anterior pituitary growth. Otx2 expression early in head development is important for establishing normal craniofacial features including development of the brain, eyes and pituitary gland. PMID:25315894

Basic Gravitational Reflexes in the Larval Frog

NASA Technical Reports Server (NTRS)

Cochran, Stephen L.

1996-01-01

This investigation was designed to determine how a primitive vertebrate, the bullfrog tadpole, is able to sense and process gravitational stimuli. Because of the phylogenetic similarities of the vestibular systems in all vertebrates, the understanding of the gravitational reflexes in this relatively simple vertebrate should elucidate a skeletal framework on a elementary level, upon which the more elaborate reflexes of higher vertebrates may be constructed. The purpose of this study was to understand how the nervous system of the larval amphibian processes gravitational information. This study involved predominantly electrophysiological investigations of the isolated, alert (forebrain removed) bullfrog tadpole head. The focus of these experiments is threefold: (1) to understand from whole extraocular nerve recordings the signals sent to the eye following static gravitational tilt of the head; (2) to localize neuronal centers responsible for generating these signals through reversible pharmacological ablation of these centers; and (3) to record intracellularly from neurons within these centers in order to determine the single neuron's role in the overall processing of the center. This study has provided information on the mechanisms by which a primitive vertebrate processes gravitational reflexes.

High intensity focused ultrasound (HIFU) ablation of benign thyroid nodules - a systematic review.

PubMed

Lang, Brian Hung-Hin; Wu, Arnold L H

2017-01-01

With an increasing number of imaging studies being done nowadays, the number of incidentally discovered thyroid nodules is expected to rise. Although many of these nodules are small and benign in nature, some do grow and may cause pressure and/or thyrotoxic symptoms. Surgical resection has traditionally been recommended for symptomatic nodules but is associated with risk of hypothyroidism, bleeding, infection, and nerve damage. High intensity focused ultrasound (HIFU) is one of the non-surgical thermal ablation techniques that may serve as an alternative in the treatment of benign thyroid nodules. The present review is to systematically evaluate the efficacy and safety of HIFU ablation. We comprehensively searched all studies that evaluated the use of HIFU ablation as a treatment of benign thyroid nodules from Medline (PubMed) and Cochrane Library electronic databases using specific keywords. All titles identified by the search strategy were independently screened by two authors. Case reports, animal studies, editorials, expert opinions, reviews without original data and studies on pediatric population were excluded. Multiple reports of the same dataset were assessed and the most representative and updated report of a study was included. Five original studies were found. All treated thyroid nodules were confirmed to be benign cytologically and either appeared solid or predominantly (>70%) solid on ultrasonography. Only one type of commercially available US-guided device with an extracorporeal probe (3 MHz) was used in all the reported treatments. No major complications including recurrent laryngeal nerve injury, skin burn or haematoma were reported in all of the studies. The overall nodule volume reduction after single session of HIFU ablation ranged between 45 and 68%, depending on nodule size and length of follow-up. Despite the few number of studies, our review appeared to suggest that HIFU is a safe and efficacious method of treating symptomatic benign thyroid nodules. However, larger-scale, prospective trials with longer follow-up period are indeed required to confirm this. In terms of the ablation itself, relative to other ablation techniques, there are still much room for improvements in shortening treatment duration and expanding the range of treatable nodules.

Ablation from calving and surface melt at lake-terminating Bridge Glacier, British Columbia, 1984-2013

NASA Astrophysics Data System (ADS)

Chernos, M.; Koppes, M.; Moore, R. D.

2016-01-01

Bridge Glacier is a lake-calving glacier in the Coast Mountains of British Columbia and has retreated over 3.55 km since 1972. The majority of this retreat has occurred since 1991. This retreat is substantially greater than what has been inferred from regional climate indices, suggesting that it has been driven primarily by calving as the glacier retreated across an overdeepened basin. In order to better understand the primary drivers of ablation, surface melt (below the equilibrium line altitude, ELA) and calving were quantified during the 2013 melt season using a distributed energy balance model (DEBM) and time-lapse imagery. Calving, estimated using areal change, velocity measurements, and assuming flotation were responsible for 23 % of the glacier's ablation below the ELA during the 2013 melt season and were limited by modest flow speeds and a small terminus cross-section. Calving and surface melt estimates from 1984 to 2013 suggest that calving was consistently a smaller contributor of ablation. Although calving was estimated to be responsible for up to 49 % of the glacier's ablation for individual seasons, averaged over multiple summers it accounted between 10 and 25 %. Calving was enhanced primarily by buoyancy and water depths, and fluxes were greatest between 2005 and 2010 as the glacier retreated over the deepest part of Bridge Lake. The recent rapid rate of calving is part of a transient stage in the glacier's retreat and is expected to diminish within 10 years as the terminus recedes into shallower water at the proximal end of the lake. These findings are in line with observations from other lake-calving glacier studies across the globe and suggest a common large-scale pattern in calving-induced retreat in lake-terminating alpine glaciers. Despite enhancing glacial retreat, calving remains a relatively small component of ablation and is expected to decrease in importance in the future. Hence, surface melt remains the primary driver of ablation at Bridge Glacier and thus projections of future retreat should be more closely tied to climate.

Architectural constraints are a major factor reducing path integration accuracy in the rat head direction cell system.

PubMed

Page, Hector J I; Walters, Daniel; Stringer, Simon M

2015-01-01

Head direction cells fire to signal the direction in which an animal's head is pointing. They are able to track head direction using only internally-derived information (path integration)In this simulation study we investigate the factors that affect path integration accuracy. Specifically, two major limiting factors are identified: rise time, the time after stimulation it takes for a neuron to start firing, and the presence of symmetric non-offset within-layer recurrent collateral connectivity. On the basis of the latter, the important prediction is made that head direction cell regions directly involved in path integration will not contain this type of connectivity; giving a theoretical explanation for architectural observations. Increased neuronal rise time is found to slow path integration, and the slowing effect for a given rise time is found to be more severe in the context of short conduction delays. Further work is suggested on the basis of our findings, which represent a valuable contribution to understanding of the head direction cell system.

Development of an endoluminal high-intensity ultrasound applicator for image-guided thermal therapy of pancreatic tumors

NASA Astrophysics Data System (ADS)

Adams, Matthew S.; Scott, Serena J.; Salgaonkar, Vasant A.; Jones, Peter D.; Plata-Camargo, Juan C.; Sommer, Graham; Diederich, Chris J.

2015-03-01

An ultrasound applicator for endoluminal thermal therapy of pancreatic tumors has been introduced and evaluated through acoustic/biothermal simulations and ex vivo experimental investigations. Endoluminal therapeutic ultrasound constitutes a minimally invasive conformal therapy and is compatible with ultrasound or MR-based image guidance. The applicator would be placed in the stomach or duodenal lumen, and sonication would be performed through the luminal wall into the tumor, with concurrent water cooling of the wall tissue to prevent its thermal injury. A finite-element (FEM) 3D acoustic and biothermal model was implemented for theoretical analysis of the approach. Parametric studies over transducer geometries and frequencies revealed that operating frequencies within 1-3 MHz maximize penetration depth and lesion volume while sparing damage to the luminal wall. Patient-specific FEM models of pancreatic head tumors were generated and used to assess the feasibility of performing endoluminal ultrasound thermal ablation and hyperthermia of pancreatic tumors. Results indicated over 80% of the volume of small tumors (~2 cm diameter) within 35 mm of the duodenum could be safely ablated in under 30 minutes or elevated to hyperthermic temperatures at steady-state. Approximately 60% of a large tumor (~5 cm diameter) model could be safely ablated by considering multiple positions of the applicator along the length of the duodenum to increase coverage. Prototype applicators containing two 3.2 MHz planar transducers were fabricated and evaluated in ex vivo porcine carcass heating experiments under MR temperature imaging (MRTI) guidance. The applicator was positioned in the stomach adjacent to the pancreas, and sonications were performed for 10 min at 5 W/cm2 applied intensity. MRTI indicated over 400C temperature rise in pancreatic tissue with heating penetration extending 3 cm from the luminal wall.

Ablation article and method

NASA Technical Reports Server (NTRS)

Erickson, W. D.; Sullivan, E. M. (Inventor)

1973-01-01

An ablation article, such as a conical heat shield, having an ablating surface is provided with at least one discrete area of at least one seed material, such as aluminum. When subjected to ablation conditions, the seed material is ablated. Radiation emanating from the ablated seed material is detected to analyze ablation effects without disturbing the ablation surface. By providing different seed materials having different radiation characteristics, the ablating effects on various areas of the ablating surface can be analyzed under any prevailing ablation conditions. The ablating article can be provided with means for detecting the radiation characteristics of the ablated seed material to provide a self-contained analysis unit.

UV solid state laser ablation of intraocular lenses

NASA Astrophysics Data System (ADS)

Apostolopoulos, A.; Lagiou, D. P.; Evangelatos, Ch.; Spyratou, E.; Bacharis, C.; Makropoulou, M.; Serafetinides, A. A.

2013-06-01

Commercially available intraocular lenses (IOLs) are manufactured from silicone and acrylic, both rigid (e.g. PMMA) and foldable (hydrophobic or hydrophilic acrylic biomaterials), behaving different mechanical and optical properties. Recently, the use of apodizing technology to design new diffractive-refractive multifocals improved the refractive outcome of these intraocular lenses, providing good distant and near vision. There is also a major ongoing effort to refine laser refractive surgery to correct other defects besides conventional refractive errors. Using phakic IOLs to treat high myopia potentially provides better predictability and optical quality than corneal-based refractive surgery. The aim of this work was to investigate the effect of laser ablation on IOL surface shaping, by drilling circular arrays of holes, with a homemade motorized rotation stage, and scattered holes on the polymer surface. In material science, the most popular lasers used for polymer machining are the UV lasers, and, therefore, we tried in this work the 3rd and the 5th harmonic of a Q-switched Nd:YAG laser (λ=355 nm and λ=213 nm respectively). The morphology of the ablated IOL surface was examined with a scanning electron microscope (SEM, Fei - Innova Nanoscope) at various laser parameters. Quantitative measurements were performed with a contact profilometer (Dektak-150), in which a mechanical stylus scanned across the surface of gold-coated IOLs (after SEM imaging) to measure variations in surface height and, finally, the ablation rates were also mathematically simulated for depicting the possible laser ablation mechanism(s). The experimental results and the theoretical modelling of UV laser interaction with polymeric IOLs are discussed in relation with the physical (optical, mechanical and thermal) properties of the material, in addition to laser radiation parameters (laser energy fluence, number of pulses). The qualitative aspects of laser ablation at λ=213 nm reveal a smooth optical surface on the intraocular lens with no irregularities, observed with other wavelengths.

Non-Invasive Targeted Peripheral Nerve Ablation Using 3D MR Neurography and MRI-Guided High-Intensity Focused Ultrasound (MR-HIFU): Pilot Study in a Swine Model.

PubMed

Huisman, Merel; Staruch, Robert M; Ladouceur-Wodzak, Michelle; van den Bosch, Maurice A; Burns, Dennis K; Chhabra, Avneesh; Chopra, Rajiv

2015-01-01

Ultrasound (US)-guided high intensity focused ultrasound (HIFU) has been proposed for noninvasive treatment of neuropathic pain and has been investigated in in-vivo studies. However, ultrasound has important limitations regarding treatment guidance and temperature monitoring. Magnetic resonance (MR)-imaging guidance may overcome these limitations and MR-guided HIFU (MR-HIFU) has been used successfully for other clinical indications. The primary purpose of this study was to evaluate the feasibility of utilizing 3D MR neurography to identify and guide ablation of peripheral nerves using a clinical MR-HIFU system. Volumetric MR-HIFU was used to induce lesions in the peripheral nerves of the lower limbs in three pigs. Diffusion-prep MR neurography and T1-weighted images were utilized to identify the target, plan treatment and immediate post-treatment evaluation. For each treatment, one 8 or 12 mm diameter treatment cell was used (sonication duration 20 s and 36 s, power 160-300 W). Peripheral nerves were extracted < 3 hours after treatment. Ablation dimensions were calculated from thermal maps, post-contrast MRI and macroscopy. Histological analysis included standard H&E staining, Masson's trichrome and toluidine blue staining. All targeted peripheral nerves were identifiable on MR neurography and T1-weighted images and could be accurately ablated with a single exposure of focused ultrasound, with peak temperatures of 60.3 to 85.7°C. The lesion dimensions as measured on MR neurography were similar to the lesion dimensions as measured on CE-T1, thermal dose maps, and macroscopy. Histology indicated major hyperacute peripheral nerve damage, mostly confined to the location targeted for ablation. Our preliminary results indicate that targeted peripheral nerve ablation is feasible with MR-HIFU. Diffusion-prep 3D MR neurography has potential for guiding therapy procedures where either nerve targeting or avoidance is desired, and may also have potential for post-treatment verification of thermal lesions without contrast injection.

Laser ablation for mesial temporal lobe epilepsy: Surgical and cognitive outcomes with and without mesial temporal sclerosis.

PubMed

Donos, Cristian; Breier, Joshua; Friedman, Elliott; Rollo, Patrick; Johnson, Jessica; Moss, Lauren; Thompson, Stephen; Thomas, Melissa; Hope, Omotola; Slater, Jeremy; Tandon, Nitin

2018-06-12

Laser interstitial thermal therapy (LITT) is a minimally invasive surgical technique for focal epilepsy. A major appeal of LITT is that it may result in fewer cognitive deficits, especially when targeting dominant hemisphere mesial temporal lobe (MTL) epilepsy. To evaluate this, as well as to determine seizure outcomes following LITT, we evaluated the relationships between ablation volumes and surgical or cognitive outcomes in 43 consecutive patients undergoing LITT for MTL epilepsy. All patients underwent unilateral LITT targeting mesial temporal structures. FreeSurfer software was used to derive cortical and subcortical segmentation of the brain (especially subregions of the MTL) using preoperative magnetic resonance imaging (MRI). Ablation volumes were outlined using a postablation T1-contrasted MRI. The percentages of the amygdala, hippocampus, and entorhinal cortex ablated were quantified objectively. The volumetric measures were regressed against changes in neuropsychological performance before and after surgery, RESULTS: A median of 73.7% of amygdala, 70.9% of hippocampus, and 28.3% of entorhinal cortex was ablated. Engel class I surgical outcome was obtained in 79.5% and 67.4% of the 43 patients at 6 and 20.3 months of follow-up, respectively. No significant differences in surgical outcomes were found across patient subgroups (hemispheric dominance, hippocampal sclerosis, or need for intracranial evaluation). Furthermore, no significant differences in volumes ablated were found between patients with Engel class IA vs Engel class II-IV outcomes. In patients undergoing LITT in the dominant hemisphere, a decline in verbal and narrative memory, but not in naming function was noted. Seizure-free outcomes following LITT may be comparable in carefully selected patients with and without MTS, and these outcomes are comparable with outcomes following microsurgical resection. Failures may result from non-mesial components of the epileptogenic network that are not affected by LITT. Cognitive declines following MTL-LITT are modest, and principally affect memory processes. Wiley Periodicals, Inc. © 2018 International League Against Epilepsy.

Terminology and reporting criteria for radiofrequency ablation of tumors in the scientific literature: systematic review of compliance with reporting standards.

PubMed

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

2014-01-01

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. 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 terms, imaging findings, therapeutic efficacy, follow-up, and complications. Accuracy of the terminology and the use of alternative terms instead of standard terminology were analyzed. In addition, disparities in accuracy of terminology in articles according to the medical specialty and the type of radiology journal were evaluated. Among the articles (n = 308) included in this study, the accuracy of the terms 'procedure or session', 'treatment', 'index tumor', 'ablation zone', 'technical success', 'primary technique effectiveness rate', 'secondary technique effectiveness rate', 'local tumor progression', 'major complication', and 'minor complication' was 97% (298/307), 97% (291/300), 8% (25/307), 65% (103/159), 55% (52/94), 33% (42/129), 94% (17/18), 45% (88/195), 99% (79/80), and 100% (77/77), respectively. The overall accuracy of each term showed a tendency to improve over the years. The most commonly used alternative terms for 'technical success' and 'local tumor progression' were 'complete ablation' and 'local (tumor) recurrence', respectively. The accuracy of terminology in articles published in radiology journals was significantly greater than that of terminology in articles published in non-radiology journals, especially in Radiology and The Journal of Vascular and Interventional Radiology. The proposal for standardization of terminology and reporting criteria for RF tumor ablation has been gaining support according to the recently published scientific reports, especially in the field of radiology. However, more work is still needed for the complete standardization of terminology.

Thromboembolic Risks of the Procedural Process in Second-Generation Cryoballoon Ablation Procedures: Analysis From Real-Time Transcranial Doppler Monitoring.

PubMed

Miyazaki, Shinsuke; Watanabe, Tomonori; Kajiyama, Takatsugu; Iwasawa, Jin; Ichijo, Sadamitsu; Nakamura, Hiroaki; Taniguchi, Hiroshi; Hirao, Kenzo; Iesaka, Yoshito

2017-12-01

Atrial fibrillation ablation is associated with substantial risks of silent cerebral events (SCEs) or silent cerebral lesions. We investigated which procedural processes during cryoballoon procedures carried a risk. Forty paroxysmal atrial fibrillation patients underwent pulmonary vein isolation using second-generation cryoballoons with single 28-mm balloon 3-minute freeze techniques. Microembolic signals (MESs) were monitored by transcranial Doppler throughout all procedures. Brain magnetic resonance imaging was obtained pre- and post-procedure in 34 patients (85.0%). Of 158 pulmonary veins, 152 (96.2%) were isolated using cryoablation, and 6 required touch-up radiofrequency ablation. A mean of 5.0±1.2 cryoballoon applications was applied, and the left atrial dwell time was 76.7±22.4 minutes. The total MES counts/procedures were 522 (426-626). Left atrial access and Flexcath sheath insertion generated 25 (11-44) and 34 (24-53) MESs. Using radiofrequency ablation for transseptal access increased the MES count during transseptal punctures. During cryoapplications, MES counts were greatest during first applications (117 [81-157]), especially after balloon stretch/deflations (43 [21-81]). Pre- and post-pulmonary vein potential mapping with Lasso catheters generated 57 (21-88) and 61 (36-88) MESs. Reinsertion of once withdrawn cryoballoons and subsequent applications produced 205 (156-310) MESs. Touch-up ablation generated 32 (19-62) MESs, whereas electric cardioversion generated no MESs. SCEs and silent cerebral lesions were detected in 11 (32.3%) and 4 (11.7%) patients, respectively. The patients with SCEs were older than those without; however, there were no significant factors associated with SCEs. A significant number of MESs and SCE/silent cerebral lesion occurrences were observed during second-generation cryoballoon ablation procedures. MESs were recorded during a variety of steps throughout the procedure; however, the majority occurred during phases with a high probability of gaseous emboli. © 2017 American Heart Association, Inc.

Recurrence and Survival Outcomes After Percutaneous Thermal Ablation of Oligometastatic Melanoma.

PubMed

White, Mariah L; Atwell, Thomas D; Kurup, A Nicholas; Schmit, Grant D; Carter, Rickey E; Geske, Jennifer R; Kottschade, Lisa A; Pulido, Jose S; Block, Matthew S; Jakub, James W; Callstrom, Matthew R; Markovic, Svetomir N

2016-03-01

To evaluate focal treatment of melanoma metastases and to explore whether any potential extended survival benefit exists in a select patient population. All patients who underwent image-guided local thermal ablation of metastatic melanoma over an 11-year period (January 1, 2002, to December 31, 2013) were retrospectively identified using an internally maintained clinical registry. Only patients with oligometastatic stage IV disease amenable to complete ablation of all clinical disease at the time of ablation were included in the analysis. Overall survival and median progression-free survival periods were calculated. Thirty-three patients with primary ocular or nonocular melanoma had 66 metastases treated in the lungs, liver, bones, or soft tissues. Eleven (33%) patients were on systemic medical therapy at the time of the procedure. The median survival time was 3.8 years (range, 0.5-10.5 years), with a 4-year estimated survival of 44.1% (95% CI, 28%-68%). Local recurrence at the ablation site developed in 15.1% (5 of 33) of the patients and 13.6% of the tumors (9 of 66). The median progression-free survival time was 4.4 months (95% CI, 1.4 months to 10.5 years), with an estimated 1-year progression-free survival of 30.3% (95% CI, 18%-51%). A subgroup analysis identified 11 patients with primary ocular melanoma and 22 with nonocular melanoma, with a median survival time of 3.9 years (range, 0.9-4.7 years) and 3.8 years (range, 0.5-10.5 years), respectively (P=.58). There were no major complications and no deaths within 30 days of the procedure. Selective use of image-guided thermal ablation of oligometastatic melanoma may provide results similar to surgical resection in terms of technical effectiveness and oncologic outcomes with minimal risk. Copyright © 2016 Mayo Foundation for Medical Education and Research. Published by Elsevier Inc. All rights reserved.

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

PubMed Central

Kang, Tae Wook; 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 terms, imaging findings, therapeutic efficacy, follow-up, and complications. Accuracy of the terminology and the use of alternative terms instead of standard terminology were analyzed. In addition, disparities in accuracy of terminology in articles according to the medical specialty and the type of radiology journal were evaluated. Results Among the articles (n = 308) included in this study, the accuracy of the terms 'procedure or session', 'treatment', 'index tumor', 'ablation zone', 'technical success', 'primary technique effectiveness rate', 'secondary technique effectiveness rate', 'local tumor progression', 'major complication', and 'minor complication' was 97% (298/307), 97% (291/300), 8% (25/307), 65% (103/159), 55% (52/94), 33% (42/129), 94% (17/18), 45% (88/195), 99% (79/80), and 100% (77/77), respectively. The overall accuracy of each term showed a tendency to improve over the years. The most commonly used alternative terms for 'technical success' and 'local tumor progression' were 'complete ablation' and 'local (tumor) recurrence', respectively. The accuracy of terminology in articles published in radiology journals was significantly greater than that of terminology in articles published in non-radiology journals, especially in Radiology and The Journal of Vascular and Interventional Radiology. Conclusion The proposal for standardization of terminology and reporting criteria for RF tumor ablation has been gaining support according to the recently published scientific reports, especially in the field of radiology. However, more work is still needed for the complete standardization of terminology. PMID:24497798

A randomised controlled trial of ablation of Barrett's oesophagus with multipolar electrocoagulation versus argon plasma coagulation in combination with acid suppression: long term results

PubMed Central

Sharma, P; Wani, S; Weston, A P; Bansal, A; Hall, M; Mathur, S; Prasad, A; Sampliner, R E

2006-01-01

Background Many modalities have been used to ablate Barrett's oesophagus (BO). However, long term results and comparative effectiveness are unknown. Aims Our aim was to compare the long term efficacy of achieving complete reversal (endoscopic and histological) between multipolar electrocoagulation (MPEC) and argon plasma coagulation (APC) in BO patients and assess factors influencing successful ablation. Methods Patients with BO, 2–6 cm long, underwent 24 hour pH testing on proton pump inhibitor (PPI) therapy. Patients were then randomised by BO length to undergo ablation with MPEC or APC every 4–8 weeks until endoscopic reversal or maximal of six treatment sessions. Results Thirty five BO patients have been followed for at least two years following endoscopic ablation, 16 treated with MPEC and 19 with APC. There was complete reversal of BO in 24 patients (69%); 75% with MPEC and 63% with APC (p = 0.49). There was no difference in the number of sessions required in the two groups. There was no difference in age, pH results, BO length, PPI dose, or hiatal hernia size between patients with and without complete reversal. One patient developed an oesophageal stricture but there were no major complications such as bleeding or perforation. Conclusions In BO patients treated with MPEC or APC in combination with acid suppression, at long term follow up, complete reversal of BO can be maintained in approximately 70% of patients, irrespective of the technique. There are no predictors associated with achieving complete reversal of BO. Continued surveillance is still indicated in the post ablative setting. As yet, these techniques are not ready for clinical application (other than for high grade dysplasia or early oesophageal adenocarcinoma) and cannot be offered outside the research arena. PMID:16905695

Reciprocal interactions between neurons and glia are required for Drosophila peripheral nervous system development.

PubMed

Sepp, Katharine J; Auld, Vanessa J

2003-09-10

A major developmental role of peripheral glia is to mediate sensory axon guidance; however, it is not known whether sensory neurons influence peripheral glial development. To determine whether glia and neurons reciprocally interact during embryonic development, we ablated each cell type by overexpressing the apoptosis gene, grim, and observed the effects on peripheral nervous system (PNS) development. When neurons are ablated, glial defects occur as a secondary effect, and vice versa. Therefore glia and neurons are codependent during embryogenesis. To further explore glial-neuronal interactions, we genetically disrupted glial migration or differentiation and observed the secondary effects on sensory neuron development. Glial migration and ensheathment of PNS axons was blocked by overexpression of activated Rho GTPase, a regulator of actin dynamics. Here, sensory axons extended to the CNS without exhibiting gross pathfinding errors. In contrast, disrupting differentiation by expression of dominant-negative Ras GTPase in glia resulted in major sensory axon pathfinding errors, similar to those seen in glial ablations. Glial overexpression of transgenic components of the epidermal growth factor receptor (EGFR) signaling pathway yielded similar sensory neuron defects and also downregulated the expression of the glial marker Neuroglian. Mutant analysis also suggested that the EGFR ligands Spitz and Vein play roles in peripheral glial development. The observations support a model in which glia express genes necessary for sensory neuron development, and these genes are potentially under the control of the EGFR/Ras signaling pathway.

Risk factors of recipient site infection in head and neck cancer patients undergoing pectoralis major myocutaneous flap reconstruction.

PubMed

Wang, Chao-Hsien; Wong, Yong-Kie; Wang, Ching-Ping; Wang, Chen-Chi; Jiang, Rong-San; Lai, Chih-Sheng; Liu, Shih-An

2015-11-01

The aim of this study was to investigate the factors associated with infection at the recipient site of pectoralis major myocutaneous flap (PMMF) of head and neck cancer patients. We retrospectively reviewed head and neck cancer patients who underwent PMMF reconstruction and identified those with recipient site infection. Variables of patients with and without infection were compared and associated factors were investigated by logistic regression model. A total of 478 patients were included in the final analysis and 183 patients (38.3%) developed recipient site infection. Lower margin of skin island, concurrent tracheotomy, diabetes mellitus, mandibular plate reconstruction, prior radiation, and peri-operative blood transfusion were independent factors associated with recipient site infection of PMMF. Skin island of PMMF beyond the eighth intercostal space markedly increased the risk of recipient site infection after major head and neck cancer surgery. Recognition of relevant factors associated with infection may help surgeons to identify those at risk.

Percutaneous intraductal radiofrequency ablation for clearance of occluded metal stent in malignant biliary obstruction: feasibility and early results.

PubMed

Pai, Madhava; Valek, Vlastimil; Tomas, Andrasina; Doros, Attila; Quaretti, Pietro; Golfieri, Rita; Mosconi, Cristina; Habib, Nagy

2014-02-01

The major complication occurring with biliary stents is stent occlusion, frequently seen because of tumour in-growth, epithelial hyperplasia, and sludge deposits, resulting in recurrent jaundice and cholangitis. We report a prospective study with the results of first in man percutaneous intraductal radiofrequency (RF) ablation to clear the blocked metal stents in patients with malignant biliary obstruction using a novel bipolar RF catheter. Nine patients with malignant biliary obstruction and blocked metal stents were included. These patients underwent intraductal biliary RF ablation through the blocked metal stent following external biliary decompression with an internal-external biliary drainage. All nine patients had their stent patency restored successfully without the use of secondary stents. Following this intervention, there was no 30-day mortality, haemorrhage, bile duct perforation, bile leak, or pancreatitis. Of the nine patients, six are alive and three patients are dead with a median follow-up of 122 (range 50-488) days and a median stent patency of 102.5 (range 50-321) days. Six patients had their stent patent at the time of last follow-up or death. Three patients with stent blockage at 321, 290, and 65 days postprocedure underwent percutaneous transhepatic drain insertion and repeat ablation. In this selective group of patients, it appears that this new approach is safe and feasible. Efficacy remains to be proven in future, randomized, prospective studies.

[Percutaneous radiofrequency ablation of hepatic metastases. Preliminary experience].

PubMed

De Baere, T; Elias, D; Ducreux, M; Dromain, C; Kuach, V; Gamal El Din, M; Sobotka, A; Lasser, P; Roche, A

1999-11-01

To evaluate the efficiency of percutaneous radiofrequency ablation in the treatment of liver metastases. Eighteen patients with 31 liver metastases, mainly from colorectal cancer, 10 - 35 mm in diameter (m = 23), underwent 26 courses of percutaneous radiofrequency ablation. Fifteen patients had previously undergone hepatectomy, and 3 patients had contra-indications to surgery. Imaging guidance was ultrasound in 21 patients, CT in 4 (tumors not seen with ultrasound), and both in 1. A generator working at 450 KHz with a maximum output power of 150 W was used to treat each lesion for 18 - 20 min. Treatment was monitored with real time ultrasound. Among the 12 patients followed more than 3 months, only one of the 24 treated lesions recurred after a mean follow up of 259 ¿ 109 days. Liver disease was controlled in 8 of the 12 patients after 90 - 509 days (m = 306). Among these 8 patients, 3 were tumor free after 559, 378 and 90 days, respectively; 2 died tumor free of non-tumoral disease (pulmonary embolism, digestive bleeding); 3 developed lung metastases treated with chemotherapy (n = 2) or surgery (n = 1). Three of the 12 patients had widespread hepatic tumor occurrence, and one patient died of these metastases. Six patients experienced mild skin burns, but no major complication was observed. Radiofrequency ablation of hepatic metastases appears safe and promising in this preliminary experience. Further investigation is needed.

To Be or Not To Be T4: Evidence of a Complex Evolutionary Pathway of Head Structure and Assembly in Giant Salmonella Virus SPN3US

PubMed Central

Ali, Bazla; Desmond, Maxim I.; Mallory, Sara A.; Benítez, Andrea D.; Buckley, Larry J.; Weintraub, Susan T.; Osier, Michael V.; Black, Lindsay W.; Thomas, Julie A.

2017-01-01

Giant Salmonella phage SPN3US has a 240-kb dsDNA genome and a large complex virion composed of many proteins for which the functions of most are undefined. We recently determined that SPN3US shares a core set of genes with related giant phages and sequenced and characterized 18 amber mutants to facilitate its use as a genetic model system. Notably, SPN3US and related giant phages contain a bolus of ejection proteins within their heads, including a multi-subunit virion RNA polymerase (vRNAP), that enter the host cell with the DNA during infection. In this study, we characterized the SPN3US virion using mass spectrometry to gain insight into its head composition and the features that its head shares with those of related giant phages and with T4 phage. SPN3US has only homologs to the T4 proteins critical for prohead shell formation, the portal and major capsid proteins, as well as to the major enzymes essential for head maturation, the prohead protease and large terminase subunit. Eight of ~50 SPN3US head proteins were found to undergo proteolytic processing at a cleavage motif by the prohead protease gp245. Gp245 undergoes auto-cleavage of its C-terminus, suggesting this is a conserved activation and/or maturation feature of related phage proteases. Analyses of essential head gene mutants showed that the five subunits of the vRNAP must be assembled for any subunit to be incorporated into the prohead, although the assembled vRNAP must then undergo subsequent major conformational rearrangements in the DNA packed capsid to allow ejection through the ~30 Å diameter tail tube for transcription from the injected DNA. In addition, ejection protein candidate gp243 was found to play a critical role in head assembly. Our analyses of the vRNAP and gp243 mutants highlighted an unexpected dichotomy in giant phage head maturation: while all analyzed giant phages have a homologous protease that processes major capsid and portal proteins, processing of ejection proteins is not always a stable/defining feature. Our identification in SPN3US, and related phages, of a diverged paralog to the prohead protease further hints toward a complicated evolutionary pathway for giant phage head structure and assembly. PMID:29187846

Safety profile of multielectrode-phased radiofrequency pulmonary vein ablation catheter and irrigated radiofrequency catheter.

PubMed

Wasmer, K; Foraita, P; Leitz, P; Güner, F; Pott, C; Lange, P S; Eckardt, L; Mönnig, G

2016-01-01

Silent cerebral lesions with the multielectrode-phased radiofrequency (RF) pulmonary vein ablation catheter (PVAC(®)) have recently been investigated. However, comparative data on safety in relation to irrigated RF ablation are missing. One hundred and fifty consecutive patients (58 ± 12 years, 56 female) underwent first pulmonary vein isolation (PVI) for atrial fibrillation (61% paroxysmal) using PVAC(®) (PVAC). Procedure data as well as in-hospital complications were compared with 300 matched patients who underwent PVI using irrigated RF (iRF). Procedure duration (148 ± 63 vs. 208 ± 70 min; P < 0.001), RF duration (24 ± 10 vs. 49 ± 25 min; P < 0.001), and fluoroscopy time (21 ± 10 vs. 35 ± 13 min; P < 0.001) were significantly shorter using PVAC. Major complication rates [major bleeding, transitoric ischaemic attack (TIA), and pericardial tamponade] were not significantly different between groups (PVAC, n = 3; 2% vs. iRF n = 17; 6%). Overall complication rate, including minor events, was similar in both groups [n = 21 (14%) vs. n = 48 (16%)]. Most of these were bleeding complications due to vascular access [n = 8 (5.3%) vs. n = 22 (7.3%)], which required surgical intervention in five patients [n = 1 (0.7%) vs. n = 4 (1.3%)]. Pericardial effusion [n = 4 (2.7%) vs. n = 19 (6.3%); pericardial tamponade requiring drainage n = 0 vs. n = 6] occurred more frequently using iRF. Two patients in each group developed a TIA (1.3% vs. 0.6%). Of note, four of five thromboembolic events in the PVAC group (two TIAs and three transient ST elevations during ablation) occurred when all 10 electrodes were used for ablation. Pulmonary vein isolation using PVAC as a 'one-shot-system' has a comparable complication rate but a different risk profile. Pericardial effusion and tamponade occurred more frequently using iRF, whereas thromboembolic events were more prevalent using PVAC. Occurrence of clinically relevant thromboembolic events might be reduced by avoidance of electrode 1 and 10 interaction and uninterrupted anticoagulation, whereas contact force sensing for iRF might minimize pericardial effusion. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

Multivariate classification of edible salts: Simultaneous Laser-Induced Breakdown Spectroscopy and Laser-Ablation Inductively Coupled Plasma Mass Spectrometry Analysis

NASA Astrophysics Data System (ADS)

Lee, Yonghoon; Nam, Sang-Ho; Ham, Kyung-Sik; Gonzalez, Jhanis; Oropeza, Dayana; Quarles, Derrick; Yoo, Jonghyun; Russo, Richard E.

2016-04-01

Laser-Induced Breakdown Spectroscopy (LIBS) and Laser-Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS), both based on laser ablation sampling, can be employed simultaneously to obtain different chemical fingerprints from a sample. We demonstrated that this analysis approach can provide complementary information for improved classification of edible salts. LIBS could detect several of the minor metallic elements along with Na and Cl, while LA-ICP-MS spectra were used to measure non-metallic and trace heavy metal elements. Principal component analysis using LIBS and LA-ICP-MS spectra showed that their major spectral variations classified the sample salts in different ways. Three classification models were developed by using partial least squares-discriminant analysis based on the LIBS, LA-ICP-MS, and their fused data. From the cross-validation performances and confusion matrices of these models, the minor metallic elements (Mg, Ca, and K) detected by LIBS and the non-metallic (I) and trace heavy metal (Ba, W, and Pb) elements detected by LA-ICP-MS provided complementary chemical information to distinguish particular salt samples.

Cord blood in regenerative medicine: do we need immune suppression?

PubMed Central

Riordan, Neil H; Chan, Kyle; Marleau, Annette M; Ichim, Thomas E

2007-01-01

Cord blood is currently used as an alternative to bone marrow as a source of stem cells for hematopoietic reconstitution after ablation. It is also under intense preclinical investigation for a variety of indications ranging from stroke, to limb ischemia, to myocardial regeneration. A major drawback in the current use of cord blood is that substantial morbidity and mortality are associated with pre-transplant ablation of the recipient hematopoietic system. Here we raise the possibility that due to unique immunological properties of both the stem cell and non-stem cell components of cord blood, it may be possible to utilize allogeneic cells for regenerative applications without needing to fully compromise the recipient immune system. Issues raised will include: graft versus host potential, the immunogeneicity of the cord blood graft, and the parallels between cord blood transplantation and fetal to maternal trafficking. The previous use of unmatched cord blood in absence of any immune ablation, as well as potential steps for widespread clinical implementation of allogeneic cord blood grafts will also be discussed. PMID:17261200

Association of Xerostomia and Ultrasonographic Features of the Major Salivary Glands After Radioactive Iodine Ablation for Papillary Thyroid Carcinoma.

PubMed

Soo Roh, Sang; Wook Kim, Dong; Jin Baek, Hye

2016-11-01

The objective of this study is to evaluate the association between xerostomia and sonographic features of the major salivary glands after patients undergo radioactive iodine ablation (RIA) for papillary thyroid carcinoma (PTC). The study included 256 consecutive patients who underwent total thyroidectomy, RIA, and neck ultrasound examinations. Changes in the ultrasound features of the parotid and submandibular glands after RIA were evaluated retrospectively by a single radiologist, on the basis of direct comparison of sonograms obtained before and after RIA. Clinical data, including the presence of xerostomia, were investigated retrospectively by the same radiologist via a review of the electronic medical records. For 111 of the 256 patients (43.4%), ultrasound examination revealed changes in the major salivary glands after RIA. The presence of xerostomia was undetermined in 85 of the 256 patients. Among the remaining 171 patients, the frequency of xerostomia was 36.8% (63/171). When patients with xerostomia were compared with those without xerostomia, no statistically significant differences in patient sex and age, the dose of RIA received, or the number of RIA sessions were noted (p > 0.05). Considering the changes in the ultrasound features of the major salivary glands after RIA, no statistically significant association was found between xerostomia and the number of involved major salivary glands or the presence of an involved submandibular gland (p > 0.05). In this study, ultrasound was unhelpful for evaluating xerostomia after RIA in patients with PTC.

Endoscopic Radiofrequency Ablation-Assisted Resection of Juvenile Nasopharyngeal Angiofibroma: Comparison with Traditional Endoscopic Technique.

PubMed

McLaughlin, Eamon J; Cunningham, Michael J; Kazahaya, Ken; Hsing, Julianna; Kawai, Kosuke; Adil, Eelam A

2016-06-01

To evaluate the feasibility of radiofrequency surgical instrumentation for endoscopic resection of juvenile nasopharyngeal angiofibroma (JNA) and to test the hypothesis that endoscopic radiofrequency ablation-assisted (RFA) resection will have superior intraoperative and/or postoperative outcomes as compared with traditional endoscopic (TE) resection techniques. Case series with chart review. Two tertiary care pediatric hospitals. Twenty-nine pediatric patients who underwent endoscopic transnasal resection of JNA from January 2000 to December 2014. Twenty-nine patients underwent RFA (n = 13) or TE (n = 16) JNA resection over the 15-year study period. Mean patient age was not statistically different between the 2 groups (P = .41); neither was their University of Pittsburgh Medical Center classification stage (P = .79). All patients underwent preoperative embolization. Mean operative times were not statistically different (P = .29). Mean intraoperative blood loss and the need for a transfusion were also not statistically different (P = .27 and .47, respectively). Length of hospital stay was not statistically different (P = .46). Recurrence rates did not differ between groups (P = .99) over a mean follow-up period of 2.3 years. There were no significant differences between RFA and TE resection in intraoperative or postoperative outcome parameters. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2016.

The effect of pneumonia on short-term outcomes and cost of care after head and neck cancer surgery.

PubMed

Semenov, Yevgeniy R; Starmer, Heather M; Gourin, Christine G

2012-09-01

The Centers for Medicare and Medicaid Services has threatened to discontinue reimbursements for ventilator-associated pneumonia (VAP) as a preventable "never event." We sought to determine the relationship between pneumonia and in-hospital mortality, complications, length of hospitalization and costs in head and neck cancer (HNCA) surgery. Retrospective cross-sectional study. Discharge data from the Nationwide Inpatient Sample for 93,663 patients who underwent an ablative procedure for a malignant oral cavity, laryngeal, hypopharyngeal, or oropharyngeal neoplasm from 2003 to 2008 were analyzed using cross-tabulations and multivariate regression modeling. VAP was rarely coded. Infectious pneumonia was significantly associated with chronic pulmonary disease (odds ratio [OR], 1.5; P < .001), while aspiration pneumonia was associated with dysphagia (OR, 2.0; P < .001). Pneumonia from any cause was associated with weight loss (OR, 3.3; P < .001), age >80 years (OR, 2.0; P = .007), comorbidity (OR, 2.3; P < .001), and major procedures (OR, 1.6; P < .001), with increased in-hospital mortality for infectious (OR, 2.9; P < .001) and aspiration pneumonia (OR, 5.3; P < .001). Both infectious and aspiration pneumonia were associated with postoperative medical and surgical complications, increased length of hospitalization, and hospital-related costs. Postoperative pneumonia is associated with increased mortality, complications, length of hospitalization, and hospital-related costs in HNCA surgical patients. Variables associated with an increased risk of pneumonia are inherent comorbidities in HNCA and known risk factors for VAP, making this a high-risk group for this never event. Caution must be used in the institution of reforms that threaten to inadequately reimburse the provision of care to this vulnerable population. Aggressive preoperative identification and treatment of underlying pulmonary disease, weight loss, and dysphagia may reduce morbidity and mortality. Copyright © 2012 The American Laryngological, Rhinological, and Otological Society, Inc.

Cervical lymph node metastasis in adenoid cystic carcinoma of the sinonasal tract, nasopharynx, lacrimal glands and external auditory canal: a collective international review.

PubMed

2016-12-01

To review reports of adenoid cystic carcinomas arising in the head and neck area outside of the major salivary glands, in order to enhance the care of patients with these unusual neoplasms. An international team of head and neck surgeons, pathologists, oncologists and radiation oncologists was assembled to explore the published experience and their own working experience of the diagnosis and treatment of adenoid cystic carcinomas arising in the vicinity of the sinonasal tract, nasopharynx, lacrimal glands and external auditory canal. The behaviour of adenoid cystic carcinoma arising in head and neck sites exclusive of the major salivary glands parallels that of tumours with a similar histology arising in the major salivary glands - these are relentless, progressive tumours, associated with high rates of mortality. Of 774 patients reviewed, at least 41 (5.3 per cent) developed documented regional node metastases. The relatively low overall incidence of nodal metastases in adenoid cystic carcinomas arising in the head and neck region outside of the major salivary glands suggests that routine elective regional lymph node dissection might not be indicated in most patients with these tumours.

Cervical lymph node metastasis in adenoid cystic carcinoma of the sinonasal tract, nasopharynx, lacrimal glands and external auditory canal: a collective international review

PubMed Central

2017-01-01

Objective To review reports of adenoid cystic carcinomas arising in the head and neck area outside of the major salivary glands, in order to enhance the care of patients with these unusual neoplasms. Methods An international team of head and neck surgeons, pathologists, oncologists and radiation oncologists was assembled to explore the published experience and their own working experience of the diagnosis and treatment of adenoid cystic carcinomas arising in the vicinity of the sinonasal tract, nasopharynx, lacrimal glands and external auditory canal. Results The behaviour of adenoid cystic carcinoma arising in head and neck sites exclusive of the major salivary glands parallels that of tumours with a similar histology arising in the major salivary glands – these are relentless, progressive tumours, associated with high rates of mortality. Of 774 patients reviewed, at least 41 (5.3 per cent) developed documented regional node metastases. Conclusion The relatively low overall incidence of nodal metastases in adenoid cystic carcinomas arising in the head and neck region outside of the major salivary glands suggests that routine elective regional lymph node dissection might not be indicated in most patients with these tumours. PMID:27839526

Efficacy and Safety of Ethanol Ablation for Branchial Cleft Cysts.

PubMed

Ha, E J; Baek, S M; Baek, J H; Shin, S Y; Han, M; Kim, C-H

2017-12-01

Branchial cleft cyst is a common congenital lesion of the neck. This study evaluated the efficacy and safety of ethanol ablation as an alternative treatment to surgery for branchial cleft cyst. Between September 2006 and October 2016, ethanol ablation was performed in 22 patients who refused an operation for a second branchial cleft cyst. After the exclusion of 2 patients who were lost to follow-up, the data of 20 patients were retrospectively evaluated. All index masses were confirmed as benign before treatment. Sonography-guided aspiration of the cystic fluid was followed by injection of absolute ethanol (99%) into the lesion. The injected volume of ethanol was 50%-80% of the volume of fluid aspirated. Therapeutic outcome, including the volume reduction ratio, therapeutic success rate (volume reduction ratio of >50% and/or no palpable mass), and complications, was evaluated. The mean index volume of the cysts was 26.4 ± 15.7 mL (range, 3.8-49.9 mL). After ablation, the mean volume of the cysts decreased to 1.2 ± 1.1 mL (range, 0.0-3.5 mL). The mean volume reduction ratio at last follow-up was 93.9% ± 7.9% (range, 75.5%-100.0%; P < .001). Therapeutic success was achieved in all nodules (20/20, 100%), and the symptomatic ( P < .001) and cosmetic ( P < .001) scores had improved significantly by the last follow-up. In 1 patient, intracystic hemorrhage developed during the aspiration; however, no major complications occurred in any patient. Ethanol ablation is an effective and safe treatment for patients with branchial cleft cysts who refuse, or are ineligible for, an operation. © 2017 by American Journal of Neuroradiology.

Is radiofrequency ablation of varicose veins a valuable option? A systematic review of the literature with a cost analysis

PubMed Central

Fisette, Jean-François; Bédard, Suzanne K.; Despatis, Marc-Antoine

2018-01-01

Background Since the 1990s, new techniques for the treatment of varicose veins have emerged, including radiofrequency ablation (RFA) and laser treatment. We performed a study to compare the safety, efficacy and outcomes of RFA compared to those of open surgery and laser ablation for the treatment of varicose veins. We also carried out a cost analysis of RFA compared to open surgery to assess whether RFA could help free up operating room time by being performed in an outpatient context. Methods We conducted a systematic literature review (publication date May 2010–September 2013 for articles in English, January 1991–September 2013 for those in French). We used several checklists to measure the quality of the studies. We also collected data on costing. Results The literature search identified 924 publications, of which 38 were retained for analysis: 15 literature reviews, 1 good-practice guideline and 22 new primary studies. The overall level of evidence was low to moderate owing to the limited sample sizes, lack of information on patient characteristics and lack of standardization of the outcome measures. However, the results obtained are consistent from study to study. In the short and medium term, RFA is considered as effective as open surgery or laser treatment (moderate level of evidence) and presents fewer major and minor complications than open surgery (low level of evidence). Radiofrequency ablation can be performed on an outpatient basis. We calculated that RFA would be about $110–$220 more expensive per patient than open surgery. Conclusion Radiofrequency ablation is a valuable alternative to open surgery and would free up operating room time in a context of low accessibility. PMID:29582749

Sites of Successful Ventricular Fibrillation Ablation in Bileaflet Mitral Valve Prolapse Syndrome.

PubMed

Syed, Faisal F; Ackerman, Michael J; McLeod, Christopher J; Kapa, Suraj; Mulpuru, Siva K; Sriram, Chenni S; Cannon, Bryan C; Asirvatham, Samuel J; Noseworthy, Peter A

2016-05-01

Although the vast majority of mitral valve prolapse (MVP) is benign, a small subset of patients, predominantly women, with bileaflet prolapse, complex ventricular ectopy (VE), and abnormal T waves comprise the recently described bileaflet MVP syndrome. We compared findings on electrophysiological study in bileaflet MVP syndrome patients with and without cardiac arrest to identify factors that may predispose to malignant ventricular arrhythmia. Fourteen consecutive bileaflet MVP syndrome patients (n=13 women; median [limits], age at index ablation, 33.8 [21.0-58.7] years; ejection fraction, 60% [45%-67%]; all ≤ moderate mitral regurgitation; n=6 with previous cardiac arrest and implantable cardioverter defibrillator shocks for ventricular fibrillation; and n=8 without implantable cardioverter defibrillator although with symptomatic complex VE) were included. The 2 groups had similar baseline echocardiographic and electrocardiographic characteristics. All patients had at least 1 left ventricular papillary or fascicular VE focus. Purkinje origin VE was identified as the ventricular fibrillation trigger in 6 of 6 cardiac arrest patients (4 from papillary muscle) and Purkinje origin of dominant VE was seen in 5 of 8 (3 from papillary muscle) nonarrest patients. Acute success was seen in 17 of 19 procedures, and a ventricular fibrillation storm occurred within 24 hours of ablation in a single patient. Repeat ablation for recurrent symptomatic arrhythmia was performed in 6 patients. At 478 (39-2099) days of follow-up, 2 cardiac arrest patients received appropriate shocks. Symptoms from VE were reduced in 12 of 14. Bileaflet MVP syndrome is characterized by fascicular and papillary muscle VE that triggers ventricular fibrillation. Ablation of clinically dominant VE foci improves symptoms and reduces appropriate implantable cardioverter defibrillator shocks. © 2016 American Heart Association, Inc.

First experience with zero-fluoroscopic ablation for supraventricular tachycardias using a novel impedance and magnetic-field-based mapping system.

PubMed

Walsh, Katie A; Galvin, Joseph; Keaney, John; Keelan, Edward; Szeplaki, Gabor

2018-02-23

Zero- and near-zero-fluoroscopic ablation techniques reduce the harmful effects of ionizing radiation during invasive electrophysiology procedures. We aimed to test the feasibility and safety of a zero-fluoroscopic strategy using a novel integrated magnetic and impedance-based electroanatomical mapping system for radiofrequency ablation (RFA) of supraventricular tachycardias (SVTs). We retrospectively studied 92 consecutive patients undergoing electrophysiology studies with/without RFA for supraventricular tachycardia (SVT) performed by a single operator at a single center. The first 42 (Group 1) underwent a conventional fluoroscopic-guided approach and the second 50 (Group 2) underwent a zero-fluoroscopic approach using the Ensite Precision ™ 3-D magnetic and impedance-based mapping system (Abbott Inc). Group 1 comprised 14 AV-nodal re-entrant tachycardia (AVNRT), 12 typical atrial flutter, 4 accessory pathway (AP), 2 atrial tachycardia (AT), and 9 diagnostic EP studies (EPS). Group 2 comprised 16 AVNRT, 17 atrial flutter, 6 AP, 3 AT, 2 AV-nodal ablations, and 7 EPS. A complete zero-fluoroscopic approach was achieved in 94% of Group 2 patients. All procedures were acutely successful, and no complications occurred. There was a significant reduction in fluoroscopy dose, dose area product, and time (p < 0.0001, for all), with no difference in procedure times. Ablation time for typical atrial flutter was shorter in Group 2 (p = 0.006). A zero-fluoroscopic strategy for diagnosis and treatment of SVTs using this novel 3D-electroanatomical mapping system is feasible in majority of patients, is safe, reduces ionizing radiation exposure, and does not compromise procedural times, success rates, or complication rates.

Is radiofrequency ablation of varicose veins a valuable option? A systematic review of the literature with a cost analysis.

PubMed

Poder, Thomas G; Fisette, Jean-François; Bédard, Suzanne K; Despatis, Marc-Antoine

2018-04-01

Since the 1990s, new techniques for the treatment of varicose veins have emerged, including radiofrequency ablation (RFA) and laser treatment. We performed a study to compare the safety, efficacy and outcomes of RFA compared to those of open surgery and laser ablation for the treatment of varicose veins. We also carried out a cost analysis of RFA compared to open surgery to assess whether RFA could help free up operating room time by being performed in an outpatient context. We conducted a systematic literature review (publication date May 2010-September 2013 for articles in English, January 1991-September 2013 for those in French). We used several checklists to measure the quality of the studies. We also collected data on costing. The literature search identified 924 publications, of which 38 were retained for analysis: 15 literature reviews, 1 good-practice guideline and 22 new primary studies. The overall level of evidence was low to moderate owing to the limited sample sizes, lack of information on patient characteristics and lack of standardization of the outcome measures. However, the results obtained are consistent from study to study. In the short and medium term, RFA is considered as effective as open surgery or laser treatment (moderate level of evidence) and presents fewer major and minor complications than open surgery (low level of evidence). Radiofrequency ablation can be performed on an outpatient basis. We calculated that RFA would be about $110-$220 more expensive per patient than open surgery. Radiofrequency ablation is a valuable alternative to open surgery and would free up operating room time in a context of low accessibility.

Transformation of a vascularised iliac crest or scapula bone to a pedicled osteomuscular transplant for reconstruction of distant defects in the head and neck region: a new method of transforming two island flaps to one longer island flap.

PubMed

Kärcher, Hans; Feichtinger, Matthias

2014-12-01

Bone defects in the maxillofacial region after ablative surgery require reconstructive surgery, usually using microvascular free flaps. This paper presents a new method of reconstructing extensive defects in patients not suitable for microvascular surgery using prefabrication of a vascularised osteomuscular flap from the scapula or iliac crest bone. Three patients who were treated with this new technique are presented. Two patients (one mandibular defect and one defect in the maxillary region) received prefabricated osteomuscular flaps from the iliac crest bone using the latissimus dorsi muscle as a pedicle. One patient also presenting a mandibular defect after tumour surgery received a scapula transplant for reconstruction of the defect using the pectoralis major muscle as pedicle. In all three cases vital bone could be transplanted. The pedicle was strainless in all three cases. Minor bone loss could be seen initially only in one case. The results are stable now and one patient received dental implants for later prosthetic treatment. The presented two-step surgery provides an excellent method for reconstruction of bony defects in the maxillofacial region in patients where microvascular surgery is not possible due to reduced state of health or lack of recipient vessels. Copyright © 2010. Published by Elsevier Ltd.

Multilevel groundwater monitoring of hydraulic head and temperature in the eastern Snake River Plain aquifer, Idaho National Laboratory, Idaho, 2007-08

USGS Publications Warehouse

Fisher, Jason C.; Twining, Brian V.

2011-01-01

During 2007 and 2008, the U.S. Geological Survey, in cooperation with the U.S. Department of Energy, collected quarterly depth-discrete measurements of fluid pressure and temperature in six boreholes located in the eastern Snake River Plain aquifer of Idaho. Each borehole was instrumented with a multilevel monitoring system consisting of a series of valved measurement ports, packer bladders, casing segments, and couplers. Hydraulic heads (head) and water temperatures in boreholes were monitored at 86 hydraulically-isolated depth intervals located 448.0 to 1,377.6 feet below land surface. The calculation of head is most sensitive to fluid pressure and the altitude of the pressure transducer at each port coupling; it is least sensitive to barometric pressure and water temperature. An analysis of errors associated with the head calculation determined the accuracy of an individual head measurement at +/- 2.3 feet. Many of the sources of measurement error are diminished when considering the differences between two closely-spaced readings of head; therefore, a +/- 0.1 foot measurement accuracy was assumed for vertical head differences (and gradients) calculated between adjacent monitoring zones. Vertical head and temperature profiles were unique to each borehole, and were characteristic of the heterogeneity and anisotropy of the eastern Snake River Plain aquifer. The vertical hydraulic gradients in each borehole remained relatively constant over time with minimum Pearson correlation coefficients between head profiles ranging from 0.72 at borehole USGS 103 to 1.00 at boreholes USGS 133 and MIDDLE 2051. Major inflections in the head profiles almost always coincided with low permeability sediment layers. The presence of a sediment layer, however, was insufficient for identifying the location of a major head change in a borehole. The vertical hydraulic gradients were defined for the major inflections in the head profiles and were as much as 2.2 feet per foot. Head gradients generally were downward in boreholes USGS 133, 134, and MIDDLE 2050A, zero in boreholes USGS 103 and 132, and exhibited a reversal in direction in borehole MIDDLE 2051. Water temperatures in all boreholes ranged from 10.2 to 16.3 degrees Celsius. Boreholes USGS 103 and 132 are in an area of concentrated volcanic vents and fissures, and measurements show water temperature decreasing with depth. All other measurements in boreholes show water temperature increasing with depth. A comparison among boreholes of the normalized mean head over time indicates a moderately positive correlation.

Over 0.5 MW green laser from sub-nanosecond giant pulsed microchip laser

NASA Astrophysics Data System (ADS)

Zheng, Lihe; Taira, Takunori

2016-03-01

A sub-nanosecond green laser with laser head sized 35 × 35 × 35 mm3 was developed from a giant pulsed microchip laser for laser processing on organic superconducting transistor with a flexible substrate. A composite monolithic Y3Al5O12 (YAG) /Nd:YAG/Cr4+:YAG/YAG crystal was designed for generating giant pulsed 1064 nm laser. A fibercoupled 30 W laser diode centered at 808 nm was used with pump pulse duration of 245 μs. The 532 nm green laser was obtained from a LiB3O5 (LBO) crystal with output energy of 150 μJ and pulse duration of 268 ps. The sub-nanosecond green laser is interesting for 2-D ablation patterns.

A New Radiofrequency Ablation Procedure to Treat Sacroiliac Joint Pain.

PubMed

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

2016-01-01

Low back pain may arise from disorders of the sacroiliac joint in up to 30% of patients. Radiofrequency ablation (RFA) of the nerves innervating the sacroiliac joint has been shown to be a safe and efficacious strategy. We aimed to develop a new RFA technique to relieve low back pain secondary to sacroiliac joint disorders. Methodology development with validation through prospective observational non-randomized trial (PONRT). Academic multidisciplinary health care system, Ohio, USA. We devised a guide-block to facilitate accurate placement of multiple electrodes to simultaneously ablate the L5 dorsal ramus and lateral branches of the S1, S2, and S3 dorsal rami. This was achieved by bipolar radiofrequency ablation (b-RFA) to create a strip lesion from the lateral border of the base of the sacral superior articular process (L5-S1 facet joint) to the lateral border of the S3 sacral foramen. We applied this technique in 31 consecutive patients and compared the operating time, x-ray exposure time and dose, and clinical outcomes with patients (n = 62) who have been treated with the cooled radiofrequency technique. Patients' level of pain relief was reported as < 50%, 50 - 80%, and > 80% pain relief at one, 3, 6, and 12 months after the procedure. The relationship between RFA technique and duration of pain relief was evaluated using interval-censored multivariable Cox regression. The new technique allowed reduction of operating time by more than 50%, x-ray exposure time and dose by more than 80%, and cost by more than $1,000 per case. The percent of patients who achieved > 50% pain reduction was significantly higher in the b-RFA group at 3, 6, and 12 months follow-up, compared to the cooled radiofrequency group. No complications were observed in either group. Although the major confounding factors were taken into account in the analysis, use of historical controls does not balance observed and unobserved potential confounding variables between groups so that the reported results are potentially confounded. Compared to the cooled radiofrequency ablation (c-RFA) technique, the new b-RFA technique reduced operating time by more than 50%, decreased x-ray exposure by more than 80%, and cut the cost by more than $1000 per case. The new method was associated with significantly improved clinical outcomes despite the limitations of the study design. Thus this new technique appeared to be safe, efficacious, and cost-effective. Key words: Sacroiliac joint pain, sacroiliac joint, low back pain, radiofrequency ablation (RFA), bipolar radiofrequency ablation (b-RFA), cooled radiofrequency ablation (c-RFA), cost-effectiveness.

Dental hard tissue ablation using mid-infrared tunable nanosecond pulsed Cr:CdSe laser.

PubMed

Lin, Taichen; Aoki, Akira; Saito, Norihito; Yumoto, Masaki; Nakajima, Sadahiro; Nagasaka, Keigo; Ichinose, Shizuko; Mizutani, Koji; Wada, Satoshi; Izumi, Yuichi

2016-12-01

Mid-infrared erbium: yttrium-aluminum-garnet (Er:YAG) and erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) lasers (2.94- and 2.78-μm, respectively) are utilized for effective dental hard tissue treatment because of their high absorption in water, hydroxide ion, or both. Recently, a mid-infrared tunable, nanosecond pulsed, all-solid-state chromium-doped: cadmium-selenide (Cr:CdSe) laser system was developed, which enables laser oscillation in the broad spectral range around 2.9 μm. The purpose of this study was to evaluate the ablation of dental hard tissue by the nanosecond pulsed Cr:CdSe laser at a wavelength range of 2.76-3.00 μm. Enamel, dentin, and cementum tissue were irradiated at a spot or line at a fluence of 0-11.20 J/cm 2 /pulse (energy output: 0-2.00 mJ/pulse) with a repetition rate of 10 Hz and beam diameter of ∼150 μm on the target (pulse width ∼250 ns). After irradiation, morphological changes, ablation threshold, depth, and efficiency, and thickness of the structurally and thermally affected layer of irradiated surfaces were analyzed using stereomicroscopy, scanning electron microscopy (SEM), and light microscopy of non-decalcified histological sections. The nanosecond pulsed irradiation without water spray effectively ablated dental hard tissue with no visible thermal damage such as carbonization. The SEM analysis revealed characteristic micro-irregularities without major melting and cracks in the lased tissue. The ablation threshold of dentin was the lowest at 2.76 μm and the highest at 3.00 μm. The histological analysis revealed minimal thermal and structural changes ∼20 μm wide on the irradiated dentin surfaces with no significant differences between wavelengths. The efficiency of dentin ablation gradually increased from 3.00 to 2.76 μm, at which point the highest ablation efficiency was observed. The nanosecond pulsed Cr:CdSe laser demonstrated an effective ablation ability of hard dental tissues, which was remarkably wavelength-dependent on dentin at the spectral range of 2.76-3.00 μm. These results demonstrate the potential feasibility of the use of pulsed Cr:CdSe laser as a novel laser system for dental treatment. Lasers Surg. Med. 48:965-977, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

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

PubMed

Wu, Po-Hung; Brace, Chris L

2016-08-21

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 highest when contrast is delivered intra-procedurally. Therefore, CECT may be feasible for real-time thermal ablation monitoring.

Hormonal Resistance And Metastasis ER-Coregulartor-Src Signaling Targeted Therapy

DTIC Science & Technology

2011-09-01

with STAT3 and cross-talk between ER~ and STAT3 play an important role in leptin -in- duced STAT3 activation’’ The II.Kl axis is the major signaling...cancer. These patients could be treated with an aromatase inhibitor (Letrozole) that ablates peripheral estrogen synthesis and ER degraders /signaling

Emerging molecular therapies targeting myocardial infarction-related arrhythmias.

PubMed

Driessen, Helen E; van Veen, Toon A B; Boink, Gerard J J

2017-04-01

Cardiac disease is the leading cause of death in the developed world. Ventricular arrhythmias associated with myocardial ischaemia and/or infarction are a major contributor to cardiovascular mortality, and require improved prevention and treatment. Drugs, devices, and radiofrequency catheter ablation have made important inroads, but have significant limitations ranging from incomplete success to undesired toxicities and major side effects. These limitations derive from the nature of the intervention. Drugs are frequently ineffective, target the entire heart, and often do not deal with the specific arrhythmia trigger or substrate. Devices can terminate rapid rhythms but at best indirectly affect the underlying disease, while ablation, even when appropriately targeted, induces additional tissue damage. In contrast, exploration of gene and cell therapies are expected to provide a targeted, non-destructive, and potentially regenerative approach to ischaemia- and infarction-related arrhythmias. Although these approaches are in the early stages of development, they carry substantial potential to advance arrhythmia prevention and treatment. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.

Intrahepatic radiofrequency ablation versus electrochemical treatment in vivo.

PubMed

Czymek, Ralf; Nassrallah, Jan; Gebhard, Maximilian; Schmidt, Andreas; Limmer, Stefan; Kleemann, Markus; Bruch, Hans-Peter; Hildebrand, Philipp

2012-06-01

Radiofrequency ablation (RFA) and electrochemical treatment (ECT) are two methods of local liver tumour ablation. The objective of this study was to compare these methods when applied in proximity to vessels in vivo. In a total of ten laparotomised pigs, we used ECT (Group A, four animals) and RFA (Group B, four animals) to create four areas of ablation per animal under ultrasound guidance within 10 mm of a vessel. Group C consisted of two control animals. Chemical laboratory tests were performed immediately before and after each procedure and on days 1, 3 and 7 after surgery. Following the last tests, the livers were harvested for morphological evaluation. The mean duration of surgery was 5 h 40 min in Group A (ECT), 2 h 47 min in Group B (RFA), and 2 h 30 min in Group C (control animals). After ECT, the harvested livers showed a mean volume of necrosis of 1.84 cm(3) ± 0.88 at the anode and 2.59 cm(3) ± 1.06 at the cathode. The presence of vessels did not influence the formation of necrotic zones. Ablation time was 67 min when a charge of 200 coulombs was delivered. We measured pH values of 1.2 (range: 0.9-1.7) at the anode and 11.7 (range: 11.0-12.1) at the cathode. In one of the 16 RFA ablations (6%), the target temperature was not reached and the procedure was discontinued. After 14 of 16 RFA procedures (88%), morphological analysis showed incomplete ablation in perivascular sites. Both ECT and RFA were associated with a reversible increase in monocyte, C-reactive protein (CRP) and aspartate aminotransferase (AST) levels. There was no significant increase in interleukin-1β (IL-1β), tumour necrosis factor-α (TNF-α) and IL-6. In the majority of cases, intrahepatic RFA in vivo leads to incomplete necrosis in proximity to vessels and the presence of histologically intact perivascular cells. Without a reduction in liver perfusion, the central application of RFA should be considered problematic. ECT is a safe alternative. It is not associated with a heat sink effect but has the disadvantage of long treatment times. Copyright © 2010 Elsevier Ltd. All rights reserved.

Benign thyroid nodules treatment using percutaneous laser ablation (PLA) and radiofrequency ablation (RFA).

PubMed

Mauri, Giovanni; Cova, Luca; Monaco, Cristian Giuseppe; Sconfienza, Luca Maria; Corbetta, Sabrina; Benedini, Stefano; Ambrogi, Federico; Milani, Valentina; Baroli, Alberto; Ierace, Tiziana; Solbiati, Luigi

2016-11-15

To evaluate the reduction over time of benign thyroid nodules treated using percutaneous laser ablation (PLA) and radiofrequency ablation (RFA) by the same equipe. Ninety patients (age 55.6 ± 14.1 years) underwent ablation for benign thyroid nodule causing compression/aesthetic dissatisfaction from 2011. Fifty-nine (age 55.8 ± 14.1 years) underwent RFA and 31 (age 55.2 ± 14.2 years) PLA, ultrasound guided. Technical success, complications, duration of ablation and treatment, energy deployed, volumetric percentage reduction at 1, 6 and 12 months were derived. A regression model for longitudinal measurements was used with random intercept and random slope. Values are expressed as mean ± standard deviation or N (%). Technical success was always obtained. No major complications occurred. Mean ablation time was 30.1 ± 13.8 vs. 13.9 ± 5.9 min (p < .0001) and mean energy deployment was 5422.3 ± 2484.5 J vs. 34 662.7 ± 15 812.3 J in PLA vs. RFA group. Mean volume reduced from 20.3 ± 16.4 ml to 13.17 ± 10.74 ml (42% ± 17% reduction) at 1st month, 8.7 ± 7.4 ml (60% ± 15% reduction) at 6th month and 7.1 ± 7.7 ml (70%% ± 16% reduction) at 12th month, in PLA group, and from 32.7 ± 19.5 ml to 17.2 ± 12.9 ml (51%±15% reduction) at 1st month, 12.8 ± 9.6 ml (64 ± 14% reduction) at 6th month and 9.9 ± 9.2 ml (74% ± 14% reduction) at 12th month in RFA group. No difference in time course of the relative volume reduction between the two techniques was found. RFA and PLA are similarly feasible, safe and effective in treating benign thyroid nodules when performed by the same equipe. RFA is faster than PLA but require significantly higher energy.

Ames Research Center Mars/Pathfinder Heat Shield Design Verification ARC-JET Test

NASA Technical Reports Server (NTRS)

Tran, Huy K.; Hui, Frank; Wercinski, Paul; Cartledge, Alan; Tauber, Mike; Tran, Duoc T.; Chen, Y. K.; Arnold, James O. (Technical Monitor)

1995-01-01

Design verification tests were performed on samples representing the aerobrake of the Mars/Pathfinder vehicle. The test specimens consisted of the SLA-561V ablator bonded to the honeycomb structure. The primary objective was to evaluate the ablation materials performance and to measure temperatures within the ablator, at the structural bondline and at the back sheet of the honeycomb structure. Other objectives were to evaluate the effect of ablative repair plug material treatment and voids in the heat shield. A total of 29 models were provided for testing in the Ames 60MW arc-jet facility. Of these, 23 models were flat-faced and six remaining models were curved edge ones, intended to simulate the conditions on the curved rim of the forebody where the maximum shear occurred. Eight sets of test conditions were used. The stagnation point heating rates varied from 47 to 240 W/cm2 and the stagnation pressures from 0.15 to 0.27 atm. (The maximum flight values are 132 W/cm2 and 0.25 atm) The majority of these runs were made at a nominal stagnation pressure of 0.25 atm. Two higher pressure runs were made to check the current (denser) ablation material for spallation, or other forms of thermal stress failure. Over 60% of the flatfaced models yielded good thermocouple data and all produced useful surface recession information. Of the five curved-edge models that were tested, only one gave good data; the remaining ones experienced model-holder failure. The test results can be summarized by noting that no failure of the ablative material was observed on any model. Also, the bondline temperature design limit of 250 C was never reached within an equivalent flight time despite a stagnation point heat load that exceeded the maximum flight value by up to 130%. At heating rates of over 200W/cm2 and stagnation pressures of 0.25 atm, or greater, the average surface recessions exceeded 0.5 cm on some models. The surface roughness increased dramatically at pressures above 0.25 atm and was four times greater at 0.27 atm than at 0.25 atm. Procured repair plug material performed much better than room-temperature cured plugs, as observed in the previous tests. Voids in the ablator did not increase local temperatures and gaps did not grow during testing.

A Guide for Local Nutrition Consultants on the Nutrition Component of Head Start Programs.

ERIC Educational Resources Information Center

Administration for Children, Youth, and Families (DHHS), Washington, DC. Head Start Bureau.

This handbook has been prepared as a guide for the nutritionist providing services to Head Start and other preschool day care programs. Introductory sections describe Project Head Start; the program's major components and aspects of the program; center-based, home-based, child and family development, and Child Development Associate (CDA) programs;…

Efficacy and Safety of Uninterrupted Low-Intensity Warfarin for Radiofrequency Catheter Ablation of Atrial Fibrillation in the Elderly.

PubMed

Xing, Yangbo; Xu, Buyun; Xu, Chao; Peng, Fang; Yang, Biao; Qiu, Yufang; Sun, Yong; Wang, Shengkai; Guo, Hangyuan

2017-09-01

No previous studies exist investigating the optimal intensity of uninterrupted anticoagulation with warfarin during radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF) in the elderly. Evaluate the efficacy and safety of continuous low-intensity warfarin therapy throughout the periprocedural period of RFCA for AF in the elderly. This is a prospective randomized study. We enrolled AF patients (age ≥ 70 years) who underwent first-time RFCA for AF. Enrolled patients were randomized to group A and group B. The international normalized ratios before ablation were maintained at 1.5 to 2.0 and 2.0 to 2.5 in group A and B, respectively. Primary end points were periprocedural thromboembolic complications and major bleeding. Secondary end points included periprocedural asymptomatic cerebral emboli (ACE) and minor bleeding. A total of 101 patients were enrolled in our study (group A: 52; group B: 49). Baseline characteristics were well balanced between the 2 groups. Only 1 patient suffered from stroke in group B. No major bleeding events occurred in either group. The incidence of new ACE lesions was comparable between the 2 groups (11.5% vs 8.2%, P = 0.82). Minor bleeding occurred in 1 of 52 (1.9%) patients in group A and in 5 of 49 (10.2%) patients in group B ( P = 0.10). Uninterrupted low-intensity warfarin for RFCA of AF might be as effective as standard-intensity warfarin in preventing periprocedural thromboembolic complications and might be associated with fewer bleeding events in the elderly.

Stereotactic Radiofrequency Ablation of Unresectable Intrahepatic Cholangiocarcinomas: A Retrospective Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haidu, Marion, E-mail: marion.haidu@i-med.ac.at; Dobrozemsky, Georg, E-mail: georg.dobroszemsky@i-med.ac.at; Schullian, Peter, E-mail: peter.schullian@i-med.ac.at

Purpose: To evaluate treatment effects, complications, and outcome of percutaneous stereotactic radiofrequency ablation (SRFA) of intrahepatic cholangiocarcinoma (ICC). Patients and Methods: Eleven consecutive patients (nine men and two women) with a total of 36 inoperable ICCs (18 initial lesions, 16 lesions newly detected during follow-up, and two local recurrences) underwent SRFA between December 2004 and June 2010. Two different radiofrequency ablation (RFA) devices with internally cooled electrodes were used. Tumor diameters ranged from 0.5 to 10 cm (median 3.0 cm). A total of 23 SRFA sessions were performed. The efficacy of SRFA was evaluated by contrast-enhanced computed tomography or magneticmore » resonance imaging 1 month after treatment and then every 3 months. Results: Primary technical effectiveness rate was 92%. Further follow-up every 3 months revealed three local recurrences (8%), two of which were successfully retreated, resulting in a secondary technical effectiveness rate of 98%. After a total of 23 RFA sessions, three major complications occurred (13%) that could be managed interventionally. Mean follow-up time was 35 months (range 12-81 months). One- and 3-year overall survival rates were 91 and 71%, respectively. The median overall survival was 60 months (according to the life table method). Eight (73%) of 11 patients were still alive at the end of follow-up. Conclusion: SRFA is effective in the treatment of unresectable ICC even if the tumor is large and located close to major vessels. SRFA shows a survival benefit compared to other palliative treatment options and may also be considered as the first-line local treatment of ICCs in selected patients.« less

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

PubMed

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

2017-04-01

For conventional needless injection, there still remain many unresolved issues such as the potential for cross-contamination, poor reliability of targeted delivery dose, and significantly painstaking procedures. As an alternative, the use of microjets generated with Er:YAG laser for delivering small doses with controlled penetration depths has been reported. In this study, a new system with two stages is evaluated for effective transdermal drug delivery. First, the skin is pre-ablated to eliminate the hard outer layer and second, laser-driven microjet penetrates the relatively weaker and freshly exposed epidermis. Each stage of operation shares a single Er:YAG laser that is suitable for skin ablation as well as for the generation of a microjet. In this study, pig skin is selected for quantification of the injection depth based on the two-stage procedure, namely pre-ablation and microjet injection. The three types of pre-ablation devised here consists of bulk ablation, fractional ablation, and fractional-rotational ablation. The number of laser pulses are 12, 18, and 24 for each ablation type. For fractional-rotational ablation, the fractional beams are rotated by 11.25° at each pulse. The drug permeation in the skin is evaluated using tissue marking dyes. The depth of penetration is quantified by a cross sectional view of the single spot injections. Multi-spot injections are also carried out to control the dose and spread of the drug. The benefits of a pre-ablation procedure prior to the actual microjet injection to the penetration is verified. The four possible combinations of injection are (a) microjet only; (b) bulk ablation and microjet injection; (c) fractional ablation and microjet injection; and (d) fractional-rotational ablation and microjet injection. Accordingly, the total depth increases with injection time for all cases. In particular, the total depth of penetration attained via fractional pre-ablation increased by 8 ∼ 11% and that of fractional-rotational pre-ablation increased by 13 ∼ 33%, when compared with the no pre-ablation or microjet only cases. A noticeable point is that the fraction-rotational pre-ablation and microjet result is comparable to the bulk ablation and microjet result of 11 ∼ 42%. The penetration depth underneath ablated stratum corneum (SC) is also measured in order to verify the pre-ablation effect. The penetration depths for each case are (a) 443 ± 104 µm; (b) 625 ± 98 µm; (c) 523 ± 95 µm; and (d) 595 ± 141 µm for microjet only, bulk ablation and microjet, fractional ablation and microjet, and fractional-rotational ablation and microjet, respectively. This is quite beneficial since any healing time associated with ablation is significantly reduced by avoiding hard-core bulk ablation. Thus the bulk pre-ablation and microjet may well be superseded by the less invasive fractiona-rotational ablation followed by the microjet injection. The density of micro-holes is 1.27 number/mm 2 for fractional ablation and 4.84 number/mm 2 for fractional-rotational ablation. The penetration depths measured underneath the ablated SC are 581 µm (fractional ablation and microjet) and 691 µm (fractional-rotational ablation and microjet). Fractional-rotational ablation increases number of micro-holes in a unit area, enabling fast reepithelialization and high drug delivery efficiency. Optimization of system parameters such as ablation time, number of ablations, and injection time will eventually ensure a macromolecule delivery technique with the potential to include vaccines, insulins, and growth hormones, all of which require deeper penetration into the skin. Lasers Surg. Med. 49:387-394, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

In Vitro and In Vivo Investigation of High-Intensity Focused Ultrasound (HIFU) Hat-Type Ablation Mode

PubMed Central

Dai, Hongya; Chen, Fei; Yan, Sijing; Ding, Xiaoya; Ma, Dazhao; Wen, Jing; Xu, Die; Zou, Jianzhong

2017-01-01

Background The aim of this study was to investigate the feasibility of the application of high-intensity focused ultrasound (HIFU) hat-type ablation mode in in vitro and in vivo models, and to compare the ablation effects of different parameter combinations. Material/Methods HIFU hat-type ablation was performed in isolated bovine liver tissue and in the liver tissue in living rabbits, and the coagulative necrosis for different parameter combinations (plane angles and irradiation order) was investigated. We also analyzed and compared the ablation effects of traditional ablation and hat-type ablation modes. Coagulative necrosis morphology was detected with TTC staining, and the coagulative necrosis volume and energy efficiency factor (EEF) were calculated and compared. Results Coagulative necrosis was observed in all the ablated groups, and the coagulative necrosis volume was much larger than the irradiation area. The coagulative necrosis induced by the hat-type ablation was more regular and controllable than the traditional ablation. The angles between the ablation planes determined the coagulative necrosis morphology, but did not affect the coagulative necrosis volume. Moreover, the irradiation order significantly influenced the coagulative necrosis. Importantly, under certain conditions, hat-type ablation achieved higher efficiency compared with the traditional ablation mode. Conclusions Compared with the traditional ablation mode, HIFU hat-type ablation effectively shortened the irradiation time, reduced the over-accumulation of energy, and increased the HIFU ablation efficiency. PMID:28699626

In Vitro and In Vivo Investigation of High-Intensity Focused Ultrasound (HIFU) Hat-Type Ablation Mode.

PubMed

Dai, Hongya; Chen, Fei; Yan, Sijing; Ding, Xiaoya; Ma, Dazhao; Wen, Jing; Xu, Die; Zou, Jianzhong

2017-07-12

BACKGROUND The aim of this study was to investigate the feasibility of the application of high-intensity focused ultrasound (HIFU) hat-type ablation mode in in vitro and in vivo models, and to compare the ablation effects of different parameter combinations. MATERIAL AND METHODS HIFU hat-type ablation was performed in isolated bovine liver tissue and in the liver tissue in living rabbits, and the coagulative necrosis for different parameter combinations (plane angles and irradiation order) was investigated. We also analyzed and compared the ablation effects of traditional ablation and hat-type ablation modes. Coagulative necrosis morphology was detected with TTC staining, and the coagulative necrosis volume and energy efficiency factor (EEF) were calculated and compared. RESULTS Coagulative necrosis was observed in all the ablated groups, and the coagulative necrosis volume was much larger than the irradiation area. The coagulative necrosis induced by the hat-type ablation was more regular and controllable than the traditional ablation. The angles between the ablation planes determined the coagulative necrosis morphology, but did not affect the coagulative necrosis volume. Moreover, the irradiation order significantly influenced the coagulative necrosis. Importantly, under certain conditions, hat-type ablation achieved higher efficiency compared with the traditional ablation mode. CONCLUSIONS Compared with the traditional ablation mode, HIFU hat-type ablation effectively shortened the irradiation time, reduced the over-accumulation of energy, and increased the HIFU ablation efficiency.

Preliminary report of associated factors in wound infection after major head and neck neoplasm operations--does the duration of prophylactic antibiotic matter?

PubMed

Liu, S-A; Tung, K-C; Shiao, J-Y; Chiu, Y-T

2008-04-01

The aim of this study was to investigate whether an extended course of prophylactic antibiotic could reduce the wound infection rate in a subtropical country. Fifty-three consecutive cases scheduled to receive major head and neck operations were randomised into one-day or three-day prophylactic antibiotic groups. Thirteen cases (24.5 per cent) developed wound infections after operations. The duration of prophylactic antibiotic was not related to the surgical wound infection. However, pre-operative haemoglobulin less than 10.5 g/dl (odds ratio: 7.24, 95 per cent confidence interval: 1.28-41.0) and reconstruction with a free flap or pectoris major myocutaneous flap during the operation (odds ratio: 11.04, 95 per cent confidence interval: 1.17-104.7) were associated factors significantly influencing post-operative wound infection. Therefore, one day of prophylactic antibiotic was effective in major head and neck procedures but should not be substituted for proper aseptic and meticulous surgical techniques.

Hard tissue ablation with a spray-assisted mid-IR laser

NASA Astrophysics Data System (ADS)

Kang, H. W.; Rizoiu, I.; Welch, A. J.

2007-12-01

The objective of this study was to understand the dominant mechanism(s) for dental enamel ablation with the application of water spray. A free-running Er,Cr:YSGG (yttrium, scandium, gallium, garnet) laser was used to ablate human enamel tissue at various radiant exposures. During dental ablation, distilled water was sprayed on the sample surface, and these results were compared to ablation without a spray (dry ablation). In order to identify dominant ablation mechanisms, transient acoustic waves were compared to ablation thresholds and the volume of material removed. The ablation profile and depth were measured using optical coherence tomography (OCT). Irregular surface modification, charring and peripheral cracks were associated with dry ablation, whereas craters for spray samples were relatively clean without thermal damage. In spite of a 60% higher ablation threshold for spray associated irradiations owing to water absorption, acoustic peak pressures were six times higher and ablation volume was up to a factor of 2 larger compared to dry ablation. The enhanced pressure and ablation performance of the spray-assisted process was the result of rapid water vaporization, material ejection with recoil stress, interstitial water explosion and possibly liquid-jet formation. With water cooling and abrasive/disruptive mechanical effects, the spray ablation can be a safe and efficient modality for dental treatment.

Safety and Efficacy of Switching Anticoagulation to Aspirin Three Months after Successful Radiofrequency Catheter Ablation of Atrial Fibrillation

PubMed Central

Uhm, Jae-Sun; Won, Hoyoun; Joung, Boyoung; Nam, Gi-Byoung; Choi, Kee-Joon; Lee, Moon-Hyoung; Kim, You-Ho

2014-01-01

Purpose Although current guidelines recommend continuing the same antithrombotic strategy regardless of rhythm control after radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF), anticoagulation has a risk of major bleeding. We evaluated the safety of switching warfarin to aspirin in patients with successful AF ablation. Materials and Methods Among 721 patients who underwent RFCA of AF, 608 patients (age, 57.3±10.9 years; 77.0% male, 75.5% paroxysmal AF) who had no evidence of AF recurrence at 3 months post-RFCA were included. We compared the thromboembolic and hemorrhagic events in patients for whom warfarin was switched to aspirin (ASA group; n=296) and patients who were kept on warfarin therapy (W group; n=312). Results There were no significant differences in CHA2DS2-VASc or HAS-BLED scores between the groups. In 30 patients in the ASA group and 37 patients in W group, AF recurred and warfarin was restarted or maintained during the 18.0±12.2 months of follow-up. There were no significant differences in thromboembolic (0.3% vs. 1.0%, p=0.342) and major bleeding incidences (0.7% vs. 0.6%, p=0.958) between ASA and W groups during the follow-up period. In the 259 patients with a CHA2DS2-VASc score ≥2, there were no significant differences in thromboembolism (0.8% and 2.2%, p=0.380) or major bleeding incidences (0.8% and 1.4%, p=0.640) between ASA and W groups. Conclusion Switching warfarin to aspirin 3 months after successful RFCA of AF could be as safe and efficacious as long-term anticoagulation even in patients with CHA2DS2-VASc score ≥2. However, strict rhythm monitoring cannot be overemphasized. PMID:25048480

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tanaka, Toshihiro, E-mail: toshihir@bf6.so-net.ne.jp; Westphal, Saskia, E-mail: swestphal@ukaachen.de; Isfort, Peter, E-mail: isfort@hia.rwth-aachen.de

2012-08-15

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

Single-site access robot-assisted epicardial mapping with a snake robot: preparation and first clinical experience.

PubMed

Neuzil, Petr; Cerny, Stepan; Kralovec, Stepan; Svanidze, Oleg; Bohuslavek, Jan; Plasil, Petr; Jehlicka, Pavel; Holy, Frantisek; Petru, Jan; Kuenzler, Richard; Sediva, Lucie

2013-06-01

CardioARM, a highly flexible "snakelike" medical robotic system (Medrobotics, Raynham, MA), has been developed to allow physicians to view, access, and perform complex procedures intrapericardially on the beating heart through a single-access port. Transthoracic epicardial catheter mapping and ablation has emerged as a strategy to treat arrhythmias, particularly ventricular arrhythmias, originating from the epicardial surface. The aim of our investigation was to determine whether the CardioARM could be used to diagnose and treat ventricular tachycardia (VT) of epicardial origin. Animal and clinical studies of the CardioARM flexible robot were performed in hybrid surgical-electrophysiology settings. In a porcine model study, single-port pericardial access, navigation, mapping, and ablation were performed in nine animals. The device was then used in a small, single-center feasibility clinical study. Three patients, all with drug-refractory VT and multiple failed endocardial ablation attempts, underwent epicardial mapping with the flexible robot. In all nine animals, navigation, mapping, and ablation were successful without hemodynamic compromise. In the human study, all three patients demonstrated a favorable safety profile, with no major adverse events through a 30-day follow-up. Two cases achieved technical success, in which an electroanatomic map of the epicardial ventricle surface was created; in the third case, blood obscured visualization. These results, although based on a limited number of experimental animals and patients, show promise and suggest that further clinical investigation on the use of the flexible robot in patients requiring epicardial mapping of VT is warranted.

Synthesis of fullerene-like tantalum disulfide nanoparticles by a gas-phase reaction and laser ablation.

PubMed

Schuffenhauer, Christoph; Parkinson, Bruce A; Jin-Phillipp, Neng Yun; Joly-Pottuz, Lucile; Martin, Jean-Michel; Popovitz-Biro, Ronit; Tenne, Reshef

2005-11-01

Motivated by the discovery of the C(60) molecule (buckminsterfullerene), the search for inorganic counterparts of this closed-cage nanostructure started in 1992 with the discovery of nested fullerene-like nanoparticles of WS(2). Inorganic fullerene-like (IF) materials have since been found in numerous two-dimensional compounds and are available in a variety of shapes that offer major applications such as in lubricants and nanocomposites. Various synthetic methodologies have been employed to achieve the right conditions for the constricted or templated growth needed for the occurrence of this new phase. In this study, IF-TaS(2) is produced from a volatile chloride precursor in the gas phase and in small yield by room temperature laser ablation both in argon and in liquid CS(2). For the gas-phase reaction, a high yield of IF nanoparticles was obtained between 400 and 600 degrees C with a low concentration of the precursor gas. The average size and the yield of the IF-TaS(2) nanoparticles decrease with temperature. Above 600 degrees C, IF nanoparticles were found in low yields and at sizes below 20 nm. The stability of the IF nanoparticles produced by the gas-phase reaction is discussed in the light of two existing theoretical models. Laser ablation in argon leads to IF nanoparticles filled with clusters of TaS(2). Agglomeration of the nanoparticles can be avoided by laser ablation in liquid CS(2).

3D Myocardial Elastography In Vivo.

PubMed

Papadacci, Clement; Bunting, Ethan A; Wan, Elaine Y; Nauleau, Pierre; Konofagou, Elisa E

2017-02-01

Strain evaluation is of major interest in clinical cardiology as it can quantify the cardiac function. Myocardial elastography, a radio-frequency (RF)-based cross-correlation method, has been developed to evaluate the local strain distribution in the heart in vivo. However, inhomogeneities such as RF ablation lesions or infarction require a three-dimensional approach to be measured accurately. In addition, acquisitions at high volume rate are essential to evaluate the cardiac strain in three dimensions. Conventional focused transmit schemes using 2D matrix arrays, trade off sufficient volume rate for beam density or sector size to image rapid moving structure such as the heart, which lowers accuracy and precision in the strain estimation. In this study, we developed 3D myocardial elastography at high volume rates using diverging wave transmits to evaluate the local axial strain distribution in three dimensions in three open-chest canines before and after radio-frequency ablation. Acquisitions were performed with a 2.5 MHz 2D matrix array fully programmable used to emit 2000 diverging waves at 2000 volumes/s. Incremental displacements and strains enabled the visualization of rapid events during the QRS complex along with the different phases of the cardiac cycle in entire volumes. Cumulative displacement and strain volumes depict high contrast between non-ablated and ablated myocardium at the lesion location, mapping the tissue coagulation. 3D myocardial strain elastography could thus become an important technique to measure the regional strain distribution in three dimensions in humans.

Spacecraft formation flying for Earth-crossing object deflections using a power limited laser ablating

NASA Astrophysics Data System (ADS)

Yoo, Sung-Moon; Song, Young-Joo; Park, Sang-Young; Choi, Kyu-Hong

2009-06-01

A formation flying strategy with an Earth-crossing object (ECO) is proposed to avoid the Earth collision. Assuming that a future conceptual spacecraft equipped with a powerful laser ablation tool already rendezvoused with a fictitious Earth collision object, the optimal required laser operating duration and direction histories are accurately derived to miss the Earth. Based on these results, the concept of formation flying between the object and the spacecraft is applied and analyzed as to establish the spacecraft's orbital motion design strategy. A fictitious "Apophis"-like object is established to impact with the Earth and two major deflection scenarios are designed and analyzed. These scenarios include the cases for the both short and long laser operating duration to avoid the Earth impact. Also, requirement of onboard laser tool's for both cases are discussed. As a result, the optimal initial conditions for the spacecraft to maintain its relative trajectory to the object are discovered. Additionally, the discovered optimal initial conditions also satisfied the optimal required laser operating conditions with no additional spacecraft's own fuel expenditure to achieve the spacecraft formation flying with the ECO. The initial conditions founded in the current research can be used as a spacecraft's initial rendezvous points with the ECO when designing the future deflection missions with laser ablation tools. The results with proposed strategy are expected to make more advances in the fields of the conceptual studies, especially for the future deflection missions using powerful laser ablation tools.

Analysis of Ablative Performance of C/C Composite Throat Containing Defects Based on X-ray 3D Reconstruction in a Solid Rocket Motor

NASA Astrophysics Data System (ADS)

Hui, Wei-Hua; Bao, Fu-Ting; Wei, Xiang-Geng; Liu, Yang

2015-12-01

In this paper, a new measuring method of ablation rate was proposed based on X-ray three-dimensional (3D) reconstruction. The ablation of 4-direction carbon/carbon composite nozzles was investigated in the combustion environment of a solid rocket motor, and the macroscopic ablation and linear recession rate were studied through the X-ray 3D reconstruction method. The results showed that the maximum relative error of the X-ray 3D reconstruction was 0.0576%, which met the minimum accuracy of the ablation analysis; along the nozzle axial direction, from convergence segment, throat to expansion segment, the ablation gradually weakened; in terms of defect ablation, the middle ablation was weak, while the ablation in both sides was more serious. In a word, the proposed reconstruction method based on X-ray about C/C nozzle ablation can construct a clear model of ablative nozzle which characterizes the details about micro-cracks, deposition, pores and surface to analyze ablation, so that this method can create the ablation curve in any surface clearly.

Microwave ablation versus radiofrequency ablation in the kidney: high-power triaxial antennas create larger ablation zones than similarly sized internally cooled electrodes.

PubMed

Laeseke, Paul F; Lee, Fred T; Sampson, Lisa A; van der Weide, Daniel W; Brace, Christopher L

2009-09-01

To determine whether microwave ablation with high-power triaxial antennas creates significantly larger ablation zones than radiofrequency (RF) ablation with similarly sized internally cooled electrodes. Twenty-eight 12-minute ablations were performed in an in vivo porcine kidney model. RF ablations were performed with a 200-W pulsed generator and either a single 17-gauge cooled electrode (n = 9) or three switched electrodes spaced 1.5 cm apart (n = 7). Microwave ablations were performed with one (n = 7), two (n = 3), or three (n = 2) 17-gauge triaxial antennas to deliver 90 W continuous power per antenna. Multiple antennas were powered simultaneously. Temperatures 1 cm from the applicator were measured during two RF and microwave ablations each. Animals were euthanized after ablation and ablation zone diameter, cross-sectional area, and circularity were measured. Comparisons between groups were performed with use of a mixed-effects model with P values less than .05 indicating statistical significance. No adverse events occurred during the procedures. Three-electrode RF (mean area, 14.7 cm(2)) and single-antenna microwave (mean area, 10.9 cm(2)) ablation zones were significantly larger than single-electrode RF zones (mean area, 5.6 cm(2); P = .001 and P = .0355, respectively). No significant differences were detected between single-antenna microwave and multiple-electrode RF. Ablation zone circularity was similar across groups (P > .05). Tissue temperatures were higher during microwave ablation (maximum temperature of 123 degrees C vs 100 degrees C for RF). Microwave ablation with high-power triaxial antennas created larger ablation zones in normal porcine kidneys than RF ablation with similarly sized applicators.

In situ measurement of gold nanoparticle production

NASA Astrophysics Data System (ADS)

Affandi, Mohd Syafiq; Bidin, Noriah; Abdullah, Mundzir; Aziz, Muhammad Safuan Abd.; Al-Azawi, Mohammed; Nugroho, Waskito

2015-01-01

The closeness of the experimental and theoretical values enables the development of an in situ characterization technique to monitor and analyze the production of gold nanoparticles (NPs), overcoming the use of high-end and expensive instrumentation. Gold NPs below the radius size of 10 nm were successfully synthesized in accordance with a few working parameters of pulse laser ablation in a liquid technique. In this report, the size, shape, concentration, and aggregation properties of gold NPs were estimated by the Mie-Gans model based on a reliable and interactive real-time absorption spectroscopy. The major features can be an important means toward determination of efficient process measures, productivity of gold NPs generated, and efficiency of the mass ablation rate. The accuracy in the measurement is confirmed via transmission electron microscopy analysis.

Natural history and management of Fanconi anemia patients with head and neck cancer: A 10-year follow-up.

PubMed

Kutler, David I; Patel, Krupa R; Auerbach, Arleen D; Kennedy, Jennifer; Lach, Francis P; Sanborn, Erica; Cohen, Marc A; Kuhel, William I; Smogorzewska, Agata

2016-04-01

To describe the management and outcomes of Fanconi anemia (FA) patients with head and neck squamous cell carcinoma. Cohort study. Demographic information, prognostic factors, therapeutic management, and survival outcomes for FA patients enrolled in the International Fanconi Anemia Registry who developed head and neck squamous cell carcinoma (HNSCC) were analyzed. Thirty-five FA patients were diagnosed with HNSCC at a mean age of 32 years. The most common site of primary cancer was the oral cavity (26 of 35, 74%). Thirty patients underwent surgical resection of the cancer. Sixteen patients received radiation therapy with an average radiation dose of 5,050 cGy. The most common toxicities were high-grade mucositis (9 of 16, 56%), hematologic abnormalities (8 of 16, 50%), and dysphagia (8 of 16, 50%). Three patients received conventional chemotherapy and had significant complications, whereas three patients who received targeted chemotherapy with cetuximab had fewer toxicities. The 5-year overall survival rate was 39%, with a cause-specific survival rate of 47%. Fanconi anemia patients have a high risk of developing aggressive HNSCC at an early age. Fanconi anemia patients can tolerate complex ablative and reconstructive surgeries, but careful postoperative care is required to reduce morbidity. The treatment of FA-associated HNSCC is difficult secondary to the poor tolerance of radiation and chemotherapy. However, radiation should be used for high-risk cancers due to the poor survival in these patients. 4. © 2015 The American Laryngological, Rhinological and Otological Society, Inc.

Natural History and Management of Fanconi Anemia Patients with Head and Neck Cancer: A 10-year Follow-up

PubMed Central

Kutler, David I.; Patel, Krupa R.; Auerbach, Arleen D.; Kennedy, Jennifer; Lach, Francis P.; Sanborn, Erica; Cohen, Marc A.; Kuhel, William I.; Smogorzewska, Agata

2015-01-01

Objective To describe the management and outcomes of Fanconi anemia (FA) patients with head and neck squamous cell carcinoma. Study Design Cohort study. Methods Demographic information, prognostic factors, therapeutic management, and survival outcomes for FA patients enrolled in the International Fanconi Anemia Registry (IFAR) who developed head and neck squamous cell carcinoma (HNSCC) were analyzed. Results 35 FA patients were diagnosed with HNSCC at a mean age of 32 years. The most common site of primary cancer was the oral cavity (26/35, 74%). Thirty patients underwent surgical resection of the cancer. Sixteen patients received radiation therapy with an average radiation dose of 5050 cGy. The most common toxicities were high-grade mucositis (9/16, 56%), hematologic abnormalities (8/16, 50%), and dysphagia (8/16, 50%). Three patients received conventional chemotherapy and had significant complications while three patients who received targeted chemotherapy with cetuximab had fewer toxicities. The 5-year overall survival rate was 39% with a cause-specific survival rate of 47%. Conclusions Fanconi anemia patients have a high risk of developing aggressive HNSCC at an early age. FA patients can tolerate complex ablative and reconstructive surgeries, but careful post-operative care is required to reduce morbidity. The treatment of FA-associated HNSCC is difficult secondary to the poor tolerance of radiation and chemotherapy. However, radiation should be used for high-risk cancers because of the poor survival in these patients. PMID:26484938

Radiofrequency catheter ablation of idiopathic ventricular arrhythmias originating from intramural foci in the left ventricular outflow tract: efficacy of sequential versus simultaneous unipolar catheter ablation.

PubMed

Yamada, Takumi; Maddox, William R; McElderry, H Thomas; Doppalapudi, Harish; Plumb, Vance J; Kay, G Neal

2015-04-01

Idiopathic ventricular arrhythmias (VAs) originating from the left ventricular outflow tract (LVOT) sometimes require catheter ablation from the endocardial and epicardial sides for their elimination, suggesting the presence of intramural VA foci. This study investigated the efficacy of sequential and simultaneous unipolar radiofrequency catheter ablation from the endocardial and epicardial sides in treating intramural LVOT VAs. Fourteen consecutive LVOT VAs, which required sequential or simultaneous irrigated unipolar radiofrequency ablation from the endocardial and epicardial sides for their elimination, were studied. The first ablation was performed at the site with the earliest local ventricular activation and best pace map on the endocardial or epicardial side. When the first ablation was unsuccessful, the second ablation was delivered on the other surface. If this sequential unipolar ablation failed, simultaneous unipolar ablation from both sides was performed. The first ablation was performed on the epicardial side in 9 VAs and endocardial side in 5 VAs. The intramural LVOT VAs were successfully eliminated by the sequential (n=9) or simultaneous (n=5) unipolar catheter ablation. Simultaneous ablation was most likely to be required for the elimination of the VAs when the distance between the endocardial and epicardial ablation sites was >8 mm and the earliest local ventricular activation time relative to the QRS onset during the VAs of <-30 ms was recorded at those ablation sites. LVOT VAs originating from intramural foci could usually be eliminated by sequential unipolar radiofrequency ablation and sometimes required simultaneous ablation from both the endocardial and epicardial sides. © 2015 American Heart Association, Inc.

Impact of 3D virtual planning on reconstruction of mandibular and maxillary surgical defects in head and neck oncology.

PubMed

Witjes, Max J H; Schepers, Rutger H; Kraeima, Joep

2018-04-01

This review describes the advances in 3D virtual planning for mandibular and maxillary reconstruction surgical defects with full prosthetic rehabilitation. The primary purpose is to provide an overview of various techniques that apply 3D technology safely in primary and secondary reconstructive cases of patients suffering from head and neck cancer. Methods have been developed to overcome the problem of control over the margin during surgery while the crucial decision with regard to resection margin and planning of osteotomies were predetermined by virtual planning. The unlimited possibilities of designing patient-specific implants can result in creative uniquely applied solutions for single cases but should be applied wisely with knowledge of biomechanical engineering principles. The high surgical accuracy of an executed 3D virtual plan provides tumor margin control during ablative surgery and the possibility of planned combined use of osseus free flaps and dental implants in the reconstruction in one surgical procedure. A thorough understanding of the effects of radiotherapy on the reconstruction, soft tissue management, and prosthetic rehabilitation is imperative in individual cases when deciding to use dental implants in patients who received radiotherapy.

Sphere-enhanced microwave ablation (sMWA) versus bland microwave ablation (bMWA): technical parameters, specific CT 3D rendering and histopathology.

PubMed

Gockner, T L; Zelzer, S; Mokry, T; Gnutzmann, D; Bellemann, N; Mogler, C; Beierfuß, A; Köllensperger, E; Germann, G; Radeleff, B A; Stampfl, U; Kauczor, H U; Pereira, P L; Sommer, C M

2015-04-01

This study was designed to compare technical parameters during ablation as well as CT 3D rendering and histopathology of the ablation zone between sphere-enhanced microwave ablation (sMWA) and bland microwave ablation (bMWA). In six sheep-livers, 18 microwave ablations were performed with identical system presets (power output: 80 W, ablation time: 120 s). In three sheep, transarterial embolisation (TAE) was performed immediately before microwave ablation using spheres (diameter: 40 ± 10 μm) (sMWA). In the other three sheep, microwave ablation was performed without spheres embolisation (bMWA). Contrast-enhanced CT, sacrifice, and liver harvest followed immediately after microwave ablation. Study goals included technical parameters during ablation (resulting power output, ablation time), geometry of the ablation zone applying specific CT 3D rendering with a software prototype (short axis of the ablation zone, volume of the largest aligned ablation sphere within the ablation zone), and histopathology (hematoxylin-eosin, Masson Goldner and TUNEL). Resulting power output/ablation times were 78.7 ± 1.0 W/120 ± 0.0 s for bMWA and 78.4 ± 1.0 W/120 ± 0.0 s for sMWA (n.s., respectively). Short axis/volume were 23.7 ± 3.7 mm/7.0 ± 2.4 cm(3) for bMWA and 29.1 ± 3.4 mm/11.5 ± 3.9 cm(3) for sMWA (P < 0.01, respectively). Histopathology confirmed the signs of coagulation necrosis as well as early and irreversible cell death for bMWA and sMWA. For sMWA, spheres were detected within, at the rim, and outside of the ablation zone without conspicuous features. Specific CT 3D rendering identifies a larger ablation zone for sMWA compared with bMWA. The histopathological signs and the detectable amount of cell death are comparable for both groups. When comparing sMWA with bMWA, TAE has no effect on the technical parameters during ablation.

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

PubMed

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

2016-01-01

To compare microwave ablation zones created by using sequential or simultaneous power delivery in ex vivo and in vivo liver tissue. All procedures were approved by the institutional animal care and use committee. Microwave ablations were performed in both ex vivo and in vivo liver models with a 2.45-GHz system capable of powering up to three antennas simultaneously. Two- and three-antenna arrays were evaluated in each model. Sequential and simultaneous ablations were created by delivering power (50 W ex vivo, 65 W in vivo) for 5 minutes per antenna (10 and 15 minutes total ablation time for sequential ablations, 5 minutes for simultaneous ablations). Thirty-two ablations were performed in ex vivo bovine livers (eight per group) and 28 in the livers of eight swine in vivo (seven per group). Ablation zone size and circularity metrics were determined from ablations excised postmortem. Mixed effects modeling was used to evaluate the influence of power delivery, number of antennas, and tissue type. On average, ablations created by using the simultaneous power delivery technique were larger than those with the sequential technique (P < .05). Simultaneous ablations were also more circular than sequential ablations (P = .0001). Larger and more circular ablations were achieved with three antennas compared with two antennas (P < .05). Ablations were generally smaller in vivo compared with ex vivo. The use of multiple antennas and simultaneous power delivery creates larger, more confluent ablations with greater temperatures than those created with sequential power delivery. © RSNA, 2015.

High-intensity focused ultrasound ablation of thyroid nodules: first human feasibility study.

PubMed

Esnault, Olivier; Franc, Brigitte; Ménégaux, Fabrice; Rouxel, Agnès; De Kerviler, Eric; Bourrier, Pierre; Lacoste, François; Chapelon, Jean-Yves; Leenhardt, Laurence

2011-09-01

Thyroid surgery is common, but complications may occur. High-intensity focused ultrasound (HIFU) is a minimally invasive alternative to surgery. We hypothesized that an optimized HIFU device could be safe and effective for ablating benign thyroid nodules without affecting neighboring structures. In this open, single-center feasibility study, 25 patients were treated with HIFU with real-time ultrasound imaging 2 weeks before a scheduled thyroidectomy for multinodular goiter. Thyroid ultrasonography imaging, thyroid function, were evaluated before and after treatment. Adverse events were carefully recorded. Each patient received HIFU for one thyroid nodule, solid or mixed, with mean diameter ≥8 mm, and no suspicion of malignancy. The HIFU device was progressively adjusted with stepwise testing. The energy level for ablation ranged from 35 to 94 J/pulse for different groups of patients. One pathologist examined all removed thyroids. Three patients discontinued treatment due to pain or skin microblister. Among the remaining 22 patients, 16 showed significant changes by ultrasound. Macroscopic and histological examinations showed that all lesions were confined to the targeted nodule without affecting neighboring structures. At pathological analysis, the extent of nodule destruction ranged from 2% to 80%. Five out of 22 patients had over 20% pathological lesions unmistakably attributed to HIFU. Seventeen cases had putative lesions including nonspecific necrosis, hemorrhage, nodule detachment, cavitations, and cysts. Among these 17 cases, 12 had both ultrasound changes and cavitation at histology that may be expected for an HIFU effect. In the last three patients ablated at the highest energy level, significant ultrasound changes and complete coagulative necrosis were observed in 80%, 78%, and 58% of the targeted area, respectively. There were no major complications of ablation. This study showed the potential efficacy of HIFU for human thyroid nodule ablation. Lesions were clearly visible by histology and ultrasound after high energy treatments, and safety and tolerability were good. We identified a power threshold for optimal necrosis of the target thyroid tissue. Further studies are ongoing to assess nodule changes at longer follow-up times.

Non-Invasive Targeted Peripheral Nerve Ablation Using 3D MR Neurography and MRI-Guided High-Intensity Focused Ultrasound (MR-HIFU): Pilot Study in a Swine Model

PubMed Central

Huisman, Merel; Staruch, Robert M.; Ladouceur-Wodzak, Michelle; van den Bosch, Maurice A.; Burns, Dennis K.; Chhabra, Avneesh; Chopra, Rajiv

2015-01-01

Purpose Ultrasound (US)-guided high intensity focused ultrasound (HIFU) has been proposed for noninvasive treatment of neuropathic pain and has been investigated in in-vivo studies. However, ultrasound has important limitations regarding treatment guidance and temperature monitoring. Magnetic resonance (MR)-imaging guidance may overcome these limitations and MR-guided HIFU (MR-HIFU) has been used successfully for other clinical indications. The primary purpose of this study was to evaluate the feasibility of utilizing 3D MR neurography to identify and guide ablation of peripheral nerves using a clinical MR-HIFU system. Methods Volumetric MR-HIFU was used to induce lesions in the peripheral nerves of the lower limbs in three pigs. Diffusion-prep MR neurography and T1-weighted images were utilized to identify the target, plan treatment and immediate post-treatment evaluation. For each treatment, one 8 or 12 mm diameter treatment cell was used (sonication duration 20 s and 36 s, power 160–300 W). Peripheral nerves were extracted < 3 hours after treatment. Ablation dimensions were calculated from thermal maps, post-contrast MRI and macroscopy. Histological analysis included standard H&E staining, Masson’s trichrome and toluidine blue staining. Results All targeted peripheral nerves were identifiable on MR neurography and T1-weighted images and could be accurately ablated with a single exposure of focused ultrasound, with peak temperatures of 60.3 to 85.7°C. The lesion dimensions as measured on MR neurography were similar to the lesion dimensions as measured on CE-T1, thermal dose maps, and macroscopy. Histology indicated major hyperacute peripheral nerve damage, mostly confined to the location targeted for ablation. Conclusion Our preliminary results indicate that targeted peripheral nerve ablation is feasible with MR-HIFU. Diffusion-prep 3D MR neurography has potential for guiding therapy procedures where either nerve targeting or avoidance is desired, and may also have potential for post-treatment verification of thermal lesions without contrast injection. PMID:26659073

The Role Of Contact Force In Atrial Fibrillation Ablation.

PubMed

Nakagawa, Hiroshi; Jackman, Warren M

2014-01-01

During radiofrequency (RF) ablation, low electrode-tissue contact force (CF) is associated with ineffective RF lesion formation, whereas excessive CF may increase the risk of steam pop and perforation. Recently, ablation catheters using two technologies have been developed to measure real-time catheter-tissue CF. One catheter uses three optical fibers to measure microdeformation of a deformable body in the catheter tip. The other catheter uses a small spring connecting the ablation tip electrode to the catheter shaft with a magnetic transmitter and sensors to measure microdeflection of the spring. Pre-clinical experimental studies have shown that 1) at constant RF power and application time, RF lesion size significantly increases with increasing CF; 2) the incidence of steam pop and thrombus also increase with increasing CF; 3) modulating RF power based on CF (i.e, high RF power at low CF and lower RF power at high CF) results in a similar and predictable RF lesion size. In clinical studies in patients undergoing pulmonary vein (PV) isolation, CF during mapping in the left atrium and PVs showed a wide range of CF and transient high CF. The most common high CF site was located at the anterior/rightward left atrial roof, directly beneath the ascending aorta. There was a poor relationship between CF and previously used surrogate parameters for CF (unipolar or bipolar atrial potential amplitude and impedance). Patients who underwent PV isolation with an average CF of <10 g experienced higher AF recurrence, whereas patients with ablation using an average CF of > 20g had lower AF recurrence. AF recurred within 12 months in 6 of 8 patients (75%) who had a mean Force-Time Integral (FTI, area under the curve for contact force vs. time) < 500 gs. In contrast, AF recurred in only 4 of 13 patients (21%) with ablation using a mean FTI >1000 gs. In another study, controlling RF power based on CF prevented steam pop and impedance rise without loss of lesion effectiveness. These studies confirm that CF is a major determinant of RF lesion size and future systems combining CF, RF power and application time may provide real-time assessment of lesion formation.

Temperature monitoring by infrared radiation measurements during ArF excimer laser ablation with cornea

NASA Astrophysics Data System (ADS)

Ishihara, Miya; Arai, Tsunenori; Sato, Shunichi; Nakano, Hironori; Obara, Minoru; Kikuchi, Makoto

1999-06-01

We measured infrared thermal radiation from porcine cornea during various fluences ArF excimer laser ablations with 1 microsecond(s) rise time. To obtain absolute temperature by means of Stefan-Boltzman law of radiation, we carried out a collection efficiency and detective sensitivity by a pre-experiment using panel heater. We measured the time course of the thermal radiation intensity with various laser fluences. We studied the relation between the peak cornea temperature during the ablation and irradiation fluences. We found the ablation situations, i.e., sub-ablation threshold, normal thermal ablation, and over-heated ablation, may be judged by both of the measured temperature transient waveforms and peak temperature. The boundary fluences corresponding to normal thermal ablation were 90 and 160 mJ/cm2. Our fast remote temperature monitoring during cornea ablation might be useful to control ablation quality/quantity of the cornea ArF laser ablation, that is PRK.

Microwave Ablation of Porcine Kidneys in vivo: Effect of two Different Ablation Modes ('Temperature Control' and 'Power Control') on Procedural Outcome

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sommer, C. M., E-mail: christof.sommer@med.uni-heidelberg.de; Arnegger, F.; Koch, V.

2012-06-15

Purpose: This study was designed to analyze the effect of two different ablation modes ('temperature control' and 'power control') of a microwave system on procedural outcome in porcine kidneys in vivo. Methods: A commercially available microwave system (Avecure Microwave Generator; MedWaves, San Diego, CA) was used. The system offers the possibility to ablate with two different ablation modes: temperature control and power control. Thirty-two microwave ablations were performed in 16 kidneys of 8 pigs. In each animal, one kidney was ablated twice by applying temperature control (ablation duration set point at 60 s, ablation temperature set point at 96 Degree-Signmore » C, automatic power set point; group I). The other kidney was ablated twice by applying power control (ablation duration set point at 60 s, ablation temperature set point at 96 Degree-Sign C, ablation power set point at 24 W; group II). Procedural outcome was analyzed: (1) technical success (e.g., system failures, duration of the ablation cycle), and (2) ablation geometry (e.g., long axis diameter, short axis diameter, and circularity). Results: System failures occurred in 0% in group I and 13% in group II. Duration of the ablation cycle was 60 {+-} 0 s in group I and 102 {+-} 21 s in group II. Long axis diameter was 20.3 {+-} 4.6 mm in group I and 19.8 {+-} 3.5 mm in group II (not significant (NS)). Short axis diameter was 10.3 {+-} 2 mm in group I and 10.5 {+-} 2.4 mm in group II (NS). Circularity was 0.5 {+-} 0.1 in group I and 0.5 {+-} 0.1 in group II (NS). Conclusions: Microwave ablations performed with temperature control showed fewer system failures and were finished faster. Both ablation modes demonstrated no significant differences with respect to ablation geometry.« less

Localization of gaps during redo ablations of paroxysmal atrial fibrillation: Preferential patterns depending on the choice of cryoballoon ablation or radiofrequency ablation for the initial procedure.

PubMed

Galand, Vincent; Pavin, Dominique; Behar, Nathalie; Auffret, Vincent; Fénéon, Damien; Behaghel, Albin; Daubert, Jean-Claude; Mabo, Philippe; Martins, Raphaël P

2016-11-01

Pulmonary vein (PV) isolation, using cryoballoon or radiofrequency ablation, is the cornerstone therapy for symptomatic paroxysmal atrial fibrillation (AF) refractory to antiarrhythmic drugs. One-third of the patients have recurrences, mainly due to PV reconnections. To describe the different locations of reconnection sites in patients who had previously undergone radiofrequency or cryoballoon ablation, and to compare the characteristics of the redo procedures in both instances. Demographic data and characteristics of the initial ablation (cryoballoon or radiofrequency) were collected. Number and localization of reconduction gaps, and redo characteristics were reviewed. Seventy-four patients scheduled for a redo ablation of paroxysmal AF were included; 38 had been treated by radiofrequency ablation and 36 by cryoballoon ablation during the first procedure. For the initial ablation, procedural and fluoroscopy times were significantly shorter for cryoballoon ablation (147.8±52.6min vs. 226.6±64.3min [P<0.001] and 37.0±17.7min vs. 50.8±22.7min [P=0.005], respectively). Overall, an identical number of gaps was found during redo procedures of cryoballoon and radiofrequency ablations. However, a significantly higher number of gaps were located in the right superior PV for patients first ablated with radiofrequency (0.9±1.0 vs. 0.5±0.9; P=0.009). Gap localization displayed different patterns. Although not significant, redo procedures of cryoballoon ablation were slightly shorter and needed shorter durations of radiofrequency to achieve PV isolation. During redo procedures, gap localization pattern is different for patients first ablated with cryoballoon or radiofrequency ablation, and right superior PV reconnections occur more frequently after radiofrequency ablation. Redo ablation of a previous cryoballoon ablation appears to be easier. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Nutritional and chemical composition of by-product fractions produced from wet reduction of individual red salmon (Oncorhynchus nerka) heads and viscera

USDA-ARS?s Scientific Manuscript database

There is growing interest for fish meals and oils made from utilizing different fish by-products (heads, viscera, frames, etc.) that come directly from the commercial processing line. The major components of fish processing waste from salmon filleting operations are heads and viscera. In order to ma...

Comparative Aspects of Management Observed by Heads of Public and Private Schools

ERIC Educational Resources Information Center

Imran, Muhammad

2010-01-01

The major purpose of the research was to compare the management aspects in public and private schools. All the heads of secondary schools of public and private sector of the Punjab province, Pakistan constituted population of the study. A sample of 216 head teachers (fifty percent from public sector schools and fifty percent private schools) was…

Nonpoor Children in Head Start: Explanations and Implications

ERIC Educational Resources Information Center

Besharov, Douglas J.; Morrow, Jeffrey S.

2007-01-01

According to the Head Start Act (1998), children are income-eligible for the program if their "families' incomes are below the poverty line." There are a number of statutory exceptions to this general rule and, according to the Head Start Bureau, the result is that about 6 percent of the children in the program are not poor. But the major national…

49 CFR 179.300-8 - Tank heads.

Code of Federal Regulations, 2013 CFR

2013-10-01

... have fusion-welded heads formed concave to pressure. Heads for fusion welding shall be an ellipsoid of revolution 2:1 ratio of major to minor axis. They shall be one piece, hot formed in one heat so as to provide..., hot formed in one heat so as to provide a straight flange at least 4 inches long. They must have snug...

49 CFR 179.300-8 - Tank heads.

Code of Federal Regulations, 2014 CFR

2014-10-01

... have fusion-welded heads formed concave to pressure. Heads for fusion welding shall be an ellipsoid of revolution 2:1 ratio of major to minor axis. They shall be one piece, hot formed in one heat so as to provide..., hot formed in one heat so as to provide a straight flange at least 4 inches long. They must have snug...

Simultaneous optical and meteor head echo measurements using the Middle Atmosphere Alomar Radar System (MAARSY): Data collection and preliminary analysis

NASA Astrophysics Data System (ADS)

Brown, P.; Stober, G.; Schult, C.; Krzeminski, Z.; Cooke, W.; Chau, J. L.

2017-07-01

The initial results of a two year simultaneous optical-radar meteor campaign are described. Analysis of 105 double-station optical meteors having plane of sky intersection angles greater than 5° and trail lengths in excess of 2 km also detected by the Middle Atmosphere Alomar Radar System (MAARSY) as head echoes was performed. These events show a median deviation in radiants between radar and optical determinations of 1.5°, with 1/3 of events having radiant agreement to less than one degree. MAARSY tends to record average speeds roughly 0.5 km/s and 1.3 km higher than optical records, in part due to the higher sensitivity of MAARSY as compared to the optical instruments. More than 98% of all head echoes are not detected with the optical system. Using this non-detection ratio and the known limiting sensitivity of the cameras, we estimate that the limiting meteoroid detection mass of MAARSY is in the 10-9-10-10 kg (astronomical limiting meteor magnitudes of +11 to +12) appropriate to speeds from 30 to 60 km/s. There is a clear trend of higher peak RCS for brighter meteors between 35 and -30 dBsm. For meteors with similar magnitudes, the MAARSY head echo radar cross-section is larger at higher speeds. Brighter meteors at fixed heights and similar speeds have consistently, on average, larger RCS values, in accordance with established scattering theory. However, our data show RCS ∝ v/2, much weaker than the normally assumed RCS ∝ v3, a consequence of our requiring head echoes to also be detectable optically. Most events show a smooth variation of RCS with height broadly following the light production behavior. A significant minority of meteors show large variations in RCS relative to the optical light curve over common height intervals, reflecting fragmentation or possibly differential ablation. No optically detected meteor occurring in the main radar beam and at times when the radar was collecting head echo data went unrecorded by MAARSY. Thus there does not appear to be any large scale bias in MAARSY head echo detections for the (comparatively) larger optical events in our dataset, even at very low speeds.

High-power and short-duration ablation for pulmonary vein isolation: Safety, efficacy, and long-term durability.

PubMed

Barkagan, Michael; Contreras-Valdes, Fernando M; Leshem, Eran; Buxton, Alfred E; Nakagawa, Hiroshi; Anter, Elad

2018-05-30

PV reconnection is often the result of catheter instability and tissue edema. High-power short-duration (HP-SD) ablation strategies have been shown to improve atrial linear continuity in acute pre-clinical models. This study compares the safety, efficacy and long-term durability of HP-SD ablation with conventional ablation. In 6 swine, 2 ablation lines were performed anterior and posterior to the crista terminalis, in the smooth and trabeculated right atrium, respectively; and the right superior PV was isolated. In 3 swine, ablation was performed using conventional parameters (THERMOCOOL-SMARTTOUCH ® SF; 30W/30 sec) and in 3 other swine using HP-SD parameters (QDOT-MICRO™, 90W/4 sec). After 30 days, linear integrity was examined by voltage mapping and pacing, and the heart and surrounding tissues were examined by histopathology. Acute line integrity was achieved with both ablation strategies; however, HP-SD ablation required 80% less RF time compared with conventional ablation (P≤0.01 for all lines). Chronic line integrity was higher with HP-SD ablation: all 3 posterior lines were continuous and transmural compared to only 1 line created by conventional ablation. In the trabeculated tissue, HP-SD ablation lesions were wider and of similar depth with 1 of 3 lines being continuous compared to 0 of 3 using conventional ablation. Chronic PVI without stenosis was evident in both groups. There were no steam-pops. Pleural markings were present in both strategies, but parenchymal lung injury was only evident with conventional ablation. HP-SD ablation strategy results in improved linear continuity, shorter ablation time, and a safety profile comparable to conventional ablation. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Echo Decorrelation Imaging of Rabbit Liver and VX2 Tumor during In Vivo Ultrasound Ablation.

PubMed

Fosnight, Tyler R; Hooi, Fong Ming; Keil, Ryan D; Ross, Alexander P; Subramanian, Swetha; Akinyi, Teckla G; Killin, Jakob K; Barthe, Peter G; Rudich, Steven M; Ahmad, Syed A; Rao, Marepalli B; Mast, T Douglas

2017-01-01

In open surgical procedures, image-ablate ultrasound arrays performed thermal ablation and imaging on rabbit liver lobes with implanted VX2 tumor. Treatments included unfocused (bulk ultrasound ablation, N = 10) and focused (high-intensity focused ultrasound ablation, N = 13) exposure conditions. Echo decorrelation and integrated backscatter images were formed from pulse-echo data recorded during rest periods after each therapy pulse. Echo decorrelation images were corrected for artifacts using decorrelation measured prior to ablation. Ablation prediction performance was assessed using receiver operating characteristic curves. Results revealed significantly increased echo decorrelation and integrated backscatter in both ablated liver and ablated tumor relative to unablated tissue, with larger differences observed in liver than in tumor. For receiver operating characteristic curves computed from all ablation exposures, both echo decorrelation and integrated backscatter predicted liver and tumor ablation with statistically significant success, and echo decorrelation was significantly better as a predictor of liver ablation. These results indicate echo decorrelation imaging is a successful predictor of local thermal ablation in both normal liver and tumor tissue, with potential for real-time therapy monitoring. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

MR imaging guidance for minimally invasive procedures

NASA Astrophysics Data System (ADS)

Wong, Terence Z.; Kettenbach, Joachim; Silverman, Stuart G.; Schwartz, Richard B.; Morrison, Paul R.; Kacher, Daniel F.; Jolesz, Ferenc A.

1998-04-01

Image guidance is one of the major challenges common to all minimally invasive procedures including biopsy, thermal ablation, endoscopy, and laparoscopy. This is essential for (1) identifying the target lesion, (2) planning the minimally invasive approach, and (3) monitoring the therapy as it progresses. MRI is an ideal imaging modality for this purpose, providing high soft tissue contrast and multiplanar imaging, capability with no ionizing radiation. An interventional/surgical MRI suite has been developed at Brigham and Women's Hospital which provides multiplanar imaging guidance during surgery, biopsy, and thermal ablation procedures. The 0.5T MRI system (General Electric Signa SP) features open vertical access, allowing intraoperative imaging to be performed. An integrated navigational system permits near real-time control of imaging planes, and provides interactive guidance for positioning various diagnostic and therapeutic probes. MR imaging can also be used to monitor cryotherapy as well as high temperature thermal ablation procedures sing RF, laser, microwave, or focused ultrasound. Design features of the interventional MRI system will be discussed, and techniques will be described for interactive image acquisition and tracking of interventional instruments. Applications for interactive and near-real-time imaging will be presented as well as examples of specific procedures performed using MRI guidance.

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

NASA Astrophysics Data System (ADS)

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.

Novel implications in the treatment of hepatocellular carcinoma

PubMed Central

Best, Jan; Schotten, Clemens; Theysohn, Jens M.; Wetter, Axel; Müller, Stefan; Radünz, Sonia; Schulze, Maren; Canbay, Ali; Dechêne, Alexander; Gerken, Guido

2017-01-01

Worldwide hepatocellular carcinoma remains one of the leading causes of cancer-related death, associated with a poor prognosis due to late diagnosis in the majority of cases. Physicians at care are frequently confronted with patients who are ineligible for curative treatment such as liver resection, transplantation or radiofrequency ablation. Besides established palliative locoregional therapies, such as ablation or chemoembolization, new treatment options, such as microwave ablation, drug-eluting bead transarterial chemoembolization or selective internal radiation therapy, are emerging; however, data from randomized controlled trials are still lacking. In order to achieve optimal tumor control, patients should receive tailored treatment concepts, considering their tumor burden, liver function and performance status, instead of strictly assigning patients to treatment modalities following algorithms that may be partly very restrictive. Palliative locoregional pretreatment might facilitate downstaging to ensure later curative resection or transplantation. In addition, the combined utilization of different locoregional treatment options or systemic co-treatment has been the subject of several trials. In cases where local tumor control cannot be achieved, or in the scenario of extrahepatic spread, sorafenib remains the only approved systemic therapy option. Alternative targeted therapies, such as immune checkpoint inhibitors have shown encouraging preliminary results, while data from phase III studies are pending. PMID:28042235

Molecular Aspects of Head and Neck Cancer Therapy

PubMed Central

Puram, Sidharth V.; Rocco, James W.

2015-01-01

Synopsis In spite of a rapidly expanding understanding of head and neck tumor biology as well as optimization of radiation, chemotherapy, and surgical treatment modalities, head and neck squamous cell carcinoma (HNSCC) remains a major cause of cancer related morbidity and mortality. Although our biologic understanding of these tumors had largely been limited to pathways driving proliferation, survival, and differentiation, the identification of HPV as a major driver of HNSCC, specifically oropharyngeal SCC, as well as recent genomic sequencing analyses of HNSCC has dramatically influenced our understanding of the underlying biology behind carcinogenesis, and in part, our approach to therapy. In particular, we are at a major molecular and clinical crossroads with an explosion of promising diagnostic and therapeutic agents that hold great promise. Here, we summarize our current understanding of HNSCC biology, including a review of recent sequencing analyses, and identify promising areas for potential diagnostic and therapeutic agents. PMID:26568543

Comprehensive head and neck trauma screening: the USS Cole experience.

PubMed

Helling, Eric R; Pfannenstiel, Travis J

2005-11-01

A prospective study was designed to determine the incidence of occult head and neck injuries after initial triage of patients following the USS Cole terrorist bombing. All 39 patients evacuated to Landstuhl Regional Medical Center underwent comprehensive head and neck examinations, regardless of known diagnoses at the time of arrival. Appropriate interventions were performed, and detailed summaries were added to the patients' records. Initial triage listed nine of 39 patients as having sustained head and neck injuries. After screening by an otolaryngology team, 23 of 39 patients were identified as having head and neck injuries requiring further care. The majority of head and neck injuries were not initially reported to the head and neck trauma service. Our conclusion is that occult head and neck injuries are common after blast injuries. Early identification and intervention by a subspecialty head and neck trauma team can aid in achieving optimal outcomes after blast injury.

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

PubMed Central

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

2016-01-01

Purpose To compare microwave ablation zones created by using sequential or simultaneous power delivery in ex vivo and in vivo liver tissue. Materials and Methods All procedures were approved by the institutional animal care and use committee. Microwave ablations were performed in both ex vivo and in vivo liver models with a 2.45-GHz system capable of powering up to three antennas simultaneously. Two- and three-antenna arrays were evaluated in each model. Sequential and simultaneous ablations were created by delivering power (50 W ex vivo, 65 W in vivo) for 5 minutes per antenna (10 and 15 minutes total ablation time for sequential ablations, 5 minutes for simultaneous ablations). Thirty-two ablations were performed in ex vivo bovine livers (eight per group) and 28 in the livers of eight swine in vivo (seven per group). Ablation zone size and circularity metrics were determined from ablations excised postmortem. Mixed effects modeling was used to evaluate the influence of power delivery, number of antennas, and tissue type. Results On average, ablations created by using the simultaneous power delivery technique were larger than those with the sequential technique (P < .05). Simultaneous ablations were also more circular than sequential ablations (P = .0001). Larger and more circular ablations were achieved with three antennas compared with two antennas (P < .05). Ablations were generally smaller in vivo compared with ex vivo. Conclusion The use of multiple antennas and simultaneous power delivery creates larger, more confluent ablations with greater temperatures than those created with sequential power delivery. © RSNA, 2015 PMID:26133361

Sphere-Enhanced Microwave Ablation (sMWA) Versus Bland Microwave Ablation (bMWA): Technical Parameters, Specific CT 3D Rendering and Histopathology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gockner, T. L., E-mail: theresa.gockner@med.uni-heidelberg.de; Zelzer, S., E-mail: s.zelzer@dkfz-heidelberg.de; Mokry, T., E-mail: theresa.mokry@med.uni-heidelberg.de

PurposeThis study was designed to compare technical parameters during ablation as well as CT 3D rendering and histopathology of the ablation zone between sphere-enhanced microwave ablation (sMWA) and bland microwave ablation (bMWA).MethodsIn six sheep-livers, 18 microwave ablations were performed with identical system presets (power output: 80 W, ablation time: 120 s). In three sheep, transarterial embolisation (TAE) was performed immediately before microwave ablation using spheres (diameter: 40 ± 10 μm) (sMWA). In the other three sheep, microwave ablation was performed without spheres embolisation (bMWA). Contrast-enhanced CT, sacrifice, and liver harvest followed immediately after microwave ablation. Study goals included technical parameters during ablation (resulting power output,more » ablation time), geometry of the ablation zone applying specific CT 3D rendering with a software prototype (short axis of the ablation zone, volume of the largest aligned ablation sphere within the ablation zone), and histopathology (hematoxylin-eosin, Masson Goldner and TUNEL).ResultsResulting power output/ablation times were 78.7 ± 1.0 W/120 ± 0.0 s for bMWA and 78.4 ± 1.0 W/120 ± 0.0 s for sMWA (n.s., respectively). Short axis/volume were 23.7 ± 3.7 mm/7.0 ± 2.4 cm{sup 3} for bMWA and 29.1 ± 3.4 mm/11.5 ± 3.9 cm{sup 3} for sMWA (P < 0.01, respectively). Histopathology confirmed the signs of coagulation necrosis as well as early and irreversible cell death for bMWA and sMWA. For sMWA, spheres were detected within, at the rim, and outside of the ablation zone without conspicuous features.ConclusionsSpecific CT 3D rendering identifies a larger ablation zone for sMWA compared with bMWA. The histopathological signs and the detectable amount of cell death are comparable for both groups. When comparing sMWA with bMWA, TAE has no effect on the technical parameters during ablation.« less

Ablative heat shield design for space shuttle

NASA Technical Reports Server (NTRS)

Seiferth, R. W.

1973-01-01

Ablator heat shield configuration optimization studies were conducted for the orbiter. Ablator and reusable surface insulation (RSI) trajectories for design studies were shaped to take advantage of the low conductance of ceramic RSI and high temperature capability of ablators. Comparative weights were established for the RSI system and for direct bond and mechanically attached ablator systems. Ablator system costs were determined for fabrication, installation and refurbishment. Cost penalties were assigned for payload weight penalties, if any. The direct bond ablator is lowest in weight and cost. A mechanically attached ablator using a magnesium subpanel is highly competitive for both weight and cost.

Reconstructive techniques in transoral robotic surgery for head and neck cancer: a North American survey.

PubMed

Konofaos, Petros; Hammond, Sarah; Ver Halen, Jon P; Samant, Sandeep

2013-02-01

Although the use of transoral robotic surgery for tumor extirpation is expanding, little is known about national trends in the reconstruction of resultant defects. An 18-question electronic survey was created by an expert panel of surgeons from the Department of Otolaryngology-Head and Neck Surgery and the Department of Plastic and Reconstructive Surgery at the University of Tennessee. Eligible participants were identified by the American Head and Neck Society Web site and from the Intuitive Surgical, Inc., Web site after review of surgeons trained in transoral robotic surgery techniques. Twenty-three of 27 preselected head and neck surgeons (85.18 percent) completed the survey. All respondents use transoral robotic surgery for head and neck tumor extirpation. The majority of the respondents [n = 17 (77.3 percent)] did not use any means of reconstruction. With respect to methods of reconstruction following transoral robotic surgery defects, the majority [n = 4 (80.0 percent)] used a free flap, a pedicled local flap [n = 3 (60.0 percent)], or a distant flap [n = 3 (60.0 percent)]. The radial forearm flap was the most commonly used free flap by all respondents. In general, the majority of survey respondents allow defects to heal secondarily or close primarily. Based on this survey, consensus indications for pedicled or free tissue transfer following transoral robotic surgery defects were primary head and neck tumors (stage T3 and T4a), pharyngeal defects with exposure of vital structures, and prior irradiation or chemoradiation to the operative site and neck.

On the origin of extraterrestrial stratospheric particles: Interplanetary dust or meteor ablation debris?. M.S. Thesis

NASA Technical Reports Server (NTRS)

Kyte, F. T.

1977-01-01

Meteor ablation debris was distinguished from unablated interplanetary dust in a collection of extraterrestrial particles collected in the stratosphere using NASA U-2 aircraft. A 62 g sample of the Murchison (C2) meteorite was artificially ablated to characterize ablation debris for comparison with the stratospheric particles. By using proper experimental conditions, artificial ablation debris can be produced that is similar to natural ablation debris. Analyses of natural fusion crusts, artificial fusion crust, and artificial ablation debris of the Murchison meteorite produced criteria for recognizing debris ablated by a primitive meteoroid. Ninety-five percent of the stratospheric particles can be described as either ablation debris from a primitive meteoroid, or as very primitive interplanetary dust.

Image-Guided Ablation of Adrenal Lesions

PubMed Central

Yamakado, Koichiro

2014-01-01

Although laparoscopic adrenalectomy has remained the standard of care for the treatment for adrenal tumors, percutaneous image-guided ablation therapy, such as chemical ablation, radiofrequency ablation, cryoablation, and microwave ablation, has been shown to be clinically useful in many nonsurgical candidates. Ablation therapy has been used to treat both functioning adenomas and malignant tumors, including primary adrenal carcinoma and metastasis. For patients with functioning adenomas, biochemical and symptomatic improvement is achieved in 96 to 100% after ablation; for patients with malignant adrenal neoplasms, however, the survival benefit from ablation therapy remains unclear, though good initial results have been reported. This article outlines the current role of ablation therapy for adrenal lesions, as well as identifying some of the technical considerations for this procedure. PMID:25049444

Head lice predictors and infestation dynamics among primary school children in Norway

PubMed Central

Birkemoe, Tone; Lindstedt, Heidi Heggen; Ottesen, Preben; Soleng, Arnulf; Næss, Øyvind; Rukke, Bjørn Arne

2016-01-01

Background. Health providers need to know which measures to take and children to prioritize in order to decrease costs associated with head lice infestations. Objective. Our aim was to determine the most important predictors for head lice and identify the major drivers of an infestation outbreak in a low-prevalence area. Methods. The study was based on three datasets of head lice prevalence (retrospective, point prevalence and prospective approach) from primary school children (ages 6–12) at 12 schools in Oslo, Norway. The tested predictors were siblings with lice, individual and household characteristics as well as class and school affiliation. Self-reported monthly incidences (prospective approach) of head lice were used to evaluate infestation dynamics. Results. Infested siblings strongly increased the odds of head lice infestation of school children (odds ratio 36, 26 and 7 in the three datasets) whereas having short hair halved the odds. Household characteristics were of minor importance, and class affiliation proved more important than school affiliation. Having head lice in one school term increased the odds of an infestation in the next, but this effect diminished over time. About 97% of all self-reported infestations were noted in two consecutive months or less. Conclusions. With the exception of hair length, we have found that individual and household characteristics are of minor importance to predict head lice infestations in a low-prevalence country and that unnoticed transmissions in school classes and families are likely to be the major driver upon outbreaks. PMID:26511728

Head lice predictors and infestation dynamics among primary school children in Norway.

PubMed

Birkemoe, Tone; Lindstedt, Heidi Heggen; Ottesen, Preben; Soleng, Arnulf; Næss, Øyvind; Rukke, Bjørn Arne

2016-02-01

Health providers need to know which measures to take and children to prioritize in order to decrease costs associated with head lice infestations. Our aim was to determine the most important predictors for head lice and identify the major drivers of an infestation outbreak in a low-prevalence area. The study was based on three datasets of head lice prevalence (retrospective, point prevalence and prospective approach) from primary school children (ages 6-12) at 12 schools in Oslo, Norway. The tested predictors were siblings with lice, individual and household characteristics as well as class and school affiliation. Self-reported monthly incidences (prospective approach) of head lice were used to evaluate infestation dynamics. Infested siblings strongly increased the odds of head lice infestation of school children (odds ratio 36, 26 and 7 in the three datasets) whereas having short hair halved the odds. Household characteristics were of minor importance, and class affiliation proved more important than school affiliation. Having head lice in one school term increased the odds of an infestation in the next, but this effect diminished over time. About 97% of all self-reported infestations were noted in two consecutive months or less. With the exception of hair length, we have found that individual and household characteristics are of minor importance to predict head lice infestations in a low-prevalence country and that unnoticed transmissions in school classes and families are likely to be the major driver upon outbreaks. © The Author 2015. Published by Oxford University Press.

Self-perception versus professional assessment of functional outcome after ablative surgery in patients with oral cancer.

PubMed

Beck-Broichsitter, Benedicta E; Huck, Jörn; Küchler, Thomas; Hauke, Daniela; Hedderich, Jürgen; Wiltfang, Jörg; Becker, Stephan T

2017-02-01

The extent of functional impairment after ablative surgery in the orofacial region may be directly reflected in a reduction in Quality of Life. This study intended to compare the patients' perception with an objective functional evaluation of the orofacial system in order to bilaterally distinguish direct influence factors. A total of 45 patients were included in this study and were asked to complete the European Organisation for Research and Treatment of Cancer Core Questionnaire (EORTC QLQ-30) and the Head and Neck 35 Module (H&N 35). Afterward one independent speech therapist evaluated the patients applying the Frenchay Dysarthria Assessment regarding four main categories: mouth opening, tongue motility, swallowing and intelligibility. Comparisons between groups were performed using Whitney-Mann U-Wilcoxon test and calculating Spearman's rho. Overall the professional assessments by the speech therapists revealed significantly higher scores regarding intelligibility, swallowing and mouth opening when compared to the patients' self-perception. Smaller tumor sizes, no bone resection and local reconstruction techniques led to significantly better functional outcomes, when assessed by speech therapists. Swallowing was perceived significantly better by patients in cases of local reconstruction. From the professionals' point of view differences were perceived in more items compared to the patients' self-assessments, who widely experienced a more severe functional impairment. Physicians should take this into account when discussing adverse therapy effects with the patients.

Photodynamic therapy using 5-aminolevulinic acid-induced photosensitization: current clinical status

NASA Astrophysics Data System (ADS)

Marcus, Stuart L.; Golub, Allyn L.; Shulman, D. Geoffrey

1995-03-01

Photodynamic therapy using 5-aminolevulinic acid-induced photosensitization (ALA PDT) via endogenous protoporphyrin IX (PpIX) synthesis has been reported as efficacious, using topical formulations, in the treatment of a variety of dermatologic diseases including superficial basal cell carcinoma, Bowen's disease, and actinic (solar) keratoses. Application of ALA PDT to the detection and treatment of both malignant and non-malignant diseases of internal organs has recently been reported. Local internal application of ALA has been used for the detection, via PpIX fluorescence, of pathological conditions of the human urinary bladder and for selective endometrial ablation in animal model systems. Systemic, oral administration of ALA has been used for ALA PDT of superficial head and neck cancer and of colorectal cancer. This paper reviews the current clinical status of ALA PDT.

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

PubMed

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

2015-09-15

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

Comparison between different thickness umbrella-shaped expandable radiofrequency electrodes (SuperSlim and CoAccess): Experimental and clinical study

PubMed Central

KODA, MASAHIKO; TOKUNAGA, SHIHO; MATONO, TOMOMITSU; SUGIHARA, TAKAAKI; NAGAHARA, TAKAKAZU; MURAWAKI, YOSHIKAZU

2011-01-01

The purpose of the present study was to compare the size and configuration of the ablation zones created by SuperSlim and CoAccess electrodes, using various ablation algorithms in ex vivo bovine liver and in clinical cases. In the experimental study, we ablated explanted bovine liver using 2 types of electrodes and 4 ablation algorithms (combinations of incremental power supply, stepwise expansion and additional low-power ablation) and evaluated the ablation area and time. In the clinical study, we compared the ablation volume and the shape of the ablation zone between both electrodes in 23 hepatocellular carcinoma (HCC) cases with the best algorithm (incremental power supply, stepwise expansion and additional low-power ablation) as derived from the experimental study. In the experimental study, the ablation area and time by the CoAccess electrode were significantly greater compared to those by the SuperSlim electrode for the single-step (algorithm 1, p=0.0209 and 0.0325, respectively) and stepwise expansion algorithms (algorithm 2, p=0.0002 and <0.0001, respectively; algorithm 3, p= 0.006 and 0.0407, respectively). However, differences were not significant for the additional low-power ablation algorithm. In the clinical study, the ablation volume and time in the CoAccess group were significantly larger and longer, respectively, compared to those in the SuperSlim group (p=0.0242 and 0.009, respectively). Round ablation zones were acquired in 91.7% of the CoAccess group, while irregular ablation zones were obtained in 45.5% of the SuperSlim group (p=0.0428). In conclusion, the CoAccess electrode achieves larger and more uniform ablation zones compared with the SuperSlim electrode, though it requires longer ablation times in experimental and clinical studies. PMID:22977647

Radiofrequency thermo-ablation of PVNS in the knee: initial results.

PubMed

Lalam, Radhesh K; Cribb, Gillian L; Cassar-Pullicino, Victor N; Cool, Wim P; Singh, Jaspreet; Tyrrell, Prudencia N M; Tins, Bernhard J; Winn, Naomi

2015-12-01

Pigmented villonodular synovitis (PVNS) is normally treated by arthroscopic or open surgical excision. We present our initial experience with radiofrequency thermo-ablation (RF ablation) of PVNS located in an inaccessible location in the knee. Review of all patients with histologically proven PVNS treated with RF ablation and with at least 2-year follow-up. Three patients met inclusion criteria and were treated with RF ablation. Two of the patients were treated successfully by one ablation procedure. One of the three patients had a recurrence which was also treated successfully by repeat RF ablation. There were no complications and all patients returned to their previous occupations following RF ablation. In this study we demonstrated the feasibility of performing RF ablation to treat PVNS in relatively inaccessible locations with curative intent. We have also discussed various post-ablation imaging appearances which can confound the assessment for residual/recurrent disease.

Change in reimbursement and costs in German oncological head and neck surgery over the last decade: ablative tongue cancer surgery and reconstruction with split-thickness skin graft vs. microvascular radial forearm flap.

PubMed

Hoefert, Sebastian; Lotter, Oliver

2018-05-01

Defects after ablative tongue cancer surgery can be reconstructed by split-thickness skin grafts or free microvascular flaps. The different surgical options may influence costs, reimbursement, and therefore possible profits. Our goal was to analyze the development of these parameters for different procedures in head and neck reconstruction in Germany over the last decade. After tumor resection and neck dissection of tongue cancer, three different scenarios were chosen to calculate costs, reimbursement, length of stay (LoS), and profits. Two options considered were reconstruction by split-thickness skin graft with (option Ia) and without (option Ib) tracheotomy. In addition, we analyzed microvascular reconstruction with radial forearm flap (option II). Furthermore, unsatisfactory results after options Ia and Ib may make secondary tongue plastic with split-thickness skin grafting necessary (option I+). The calculations were performed considering the German Diagnosis Related Group (DRG) system and compared to the specific DRG cost data of 250 German reference hospitals. The overall average length of stay (aLoS) declined from 16.7 to 12.8 days with a reduction in every option. Until 2011, all options showed similar accumulated DRG reimbursement. From 2012 onwards, earnings almost doubled for option II due to changes in the DRG allocation. As was expected, the highest costs were observed in option II. Profits (reimbursement minus costs) were also highest for option II (mean 2052 €, maximum 3630 Euros in 2015) followed by options Ia (765 €) and Ib/I+ (681 €). Average profits over time would be 17 to 19% higher if adjusted for inflation. We showed the development of the DRG allocation of two commonly used methods of reconstruction after ablative tongue cancer surgery and the associated LoS, reimbursement, costs, and profits. As expected, the highest values were found for microvascular reconstruction. Microvascular reconstruction may also be the primary choice of treatment from a medical point of view. However, prolonged operation times, intensive care, and hospital stay in connection with complex microvascular operations can easily turn profits into losses as opposed to the results of simple, reliable, and fast split-thickness skin grafting. The inflation rate influences profits in reimbursement systems where costs are based on a previous period of time. Surgeons find themselves daily in an area of conflict between economic interests and medical decision-making. Due to its multidimensional aspects, the choice of the reconstructive technique should be primarily based on the best medical care for the patient. But there should also be awareness of the economic risk of all three surgical procedures.

Risk factors for head injury events in professional rugby union: a video analysis of 464 head injury events to inform proposed injury prevention strategies.

PubMed

Tucker, Ross; Raftery, Martin; Kemp, Simon; Brown, James; Fuller, Gordon; Hester, Ben; Cross, Matthew; Quarrie, Ken

2017-08-01

The tackle is responsible for the majority of head injuries during rugby union. In order to address head injury risk, risk factors during the tackle must first be identified. This study analysed tackle characteristics in the professional game in order to inform potential interventions. 464 tackles resulting in a head injury assessment (HIA) were analysed in detail, with tackle type, direction, speed, acceleration, nature of head contact and player body position the characteristics of interest. Propensity to cause an HIA was significantly greater for active shoulder tackles, front-on tackles, high speeder tackles and an accelerating tackler. Head contact between a tackler's head and ball carrier's head or shoulder was significantly more likely to cause an HIA than contact below the level of the shoulder (incident rate ratio (IRR) 4.25, 95%-CI 3.38 to 5.35). The tackler experiences the majority (78%) of HIAs when head-to-head contact occurs. An upright tackler was 1.5 times more likely to experience an HIA than a bent at the waist tackler (IRR 1.44, 95% CI 1.18 to 1.76). This study confirms that energy transfer in the tackle is a risk factor for head injury, since direction, type and speed all influence HIA propensity. The study provides evidence that body position and the height of tackles should be a focus for interventions, since lowering height and adopting a bent at the waist body position is associated with reduced risk for both tacklers and ball carriers. To this end, World Rugby has implemented law change based on the present data. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Automated microwave ablation therapy planning with single and multiple entry points

NASA Astrophysics Data System (ADS)

Liu, Sheena X.; Dalal, Sandeep; Kruecker, Jochen

2012-02-01

Microwave ablation (MWA) has become a recommended treatment modality for interventional cancer treatment. Compared with radiofrequency ablation (RFA), MWA provides more rapid and larger-volume tissue heating. It allows simultaneous ablation from different entry points and allows users to change the ablation size by controlling the power/time parameters. Ablation planning systems have been proposed in the past, mainly addressing the needs for RFA procedures. Thus a planning system addressing MWA-specific parameters and workflows is highly desirable to help physicians achieve better microwave ablation results. In this paper, we design and implement an automated MWA planning system that provides precise probe locations for complete coverage of tumor and margin. We model the thermal ablation lesion as an ellipsoidal object with three known radii varying with the duration of the ablation and the power supplied to the probe. The search for the best ablation coverage can be seen as an iterative optimization problem. The ablation centers are steered toward the location which minimizes both un-ablated tumor tissue and the collateral damage caused to the healthy tissue. We assess the performance of our algorithm using simulated lesions with known "ground truth" optimal coverage. The Mean Localization Error (MLE) between the computed ablation center in 3D and the ground truth ablation center achieves 1.75mm (Standard deviation of the mean (STD): 0.69mm). The Mean Radial Error (MRE) which is estimated by comparing the computed ablation radii with the ground truth radii reaches 0.64mm (STD: 0.43mm). These preliminary results demonstrate the accuracy and robustness of the described planning algorithm.

A cost-utility analysis of ablative therapy for Barrett’s esophagus

PubMed Central

Inadomi, John M.; Somsouk, Ma; Madanick, Ryan D.; Thomas, Jennifer P.; Shaheen, Nicholas J.

2009-01-01

Background & Aims Recommendations for patients with Barrett’s esophagus (BE) include endoscopic surveillance with esophagectomy for early-stage cancer, although new technologies to ablate dysplasia and metaplasia are available. This study compares the cost-utility of ablation with that of endoscopic surveillance strategies. Methods A decision analysis model was created to examine a population of patients with BE (mean age 50), with separate analyses for patients with no dysplasia, low-grade dysplasia (LGD), or high-grade dysplasia (HGD). Strategies compared were: no endoscopic surveillance; endoscopic surveillance with ablation for incident dysplasia; immediate ablation followed by endoscopic surveillance in all patients or limited to patients in whom metaplasia persisted, and esophagectomy. Ablation modalities modeled included radiofrequency, argon plasma coagulation, multipolar electrocoagulation and photodynamic therapy. Results Endoscopic ablation for patients with HGD could increase life expectancy by 3 quality-adjusted years at an incremental cost of < $6,000, compared with no intervention. Patients with LGD or no dysplasia can also be optimally managed with ablation, but continued surveillance after eradication of metaplasia is expensive. If ablation permanently eradicates at least 28% of LGD or 40% of non-dysplastic metaplasias, ablation would be preferred to surveillance. Conclusions Endoscopic ablation could be the preferred strategy for managing patients with BE with HGD. Ablation might also be preferred in subjects with LGD or no dysplasia, but the cost-effectiveness depends on the long-term effectiveness of ablation and whether surveillance endoscopy can be discontinued following successful ablation. As further post-ablation data become available, the optimal management strategy will be clarified. PMID:19272389

Femtosecond laser for cavity preparation in enamel and dentin: ablation efficiency related factors.

PubMed

Chen, H; Li, H; Sun, Yc; Wang, Y; Lü, Pj

2016-02-11

To study the effects of laser fluence (laser energy density), scanning line spacing and ablation depth on the efficiency of a femtosecond laser for three-dimensional ablation of enamel and dentin. A diode-pumped, thin-disk femtosecond laser (wavelength 1025 nm, pulse width 400 fs) was used for the ablation of enamel and dentin. The laser spot was guided in a series of overlapping parallel lines on enamel and dentin surfaces to form a three-dimensional cavity. The depth and volume of the ablated cavity was then measured under a 3D measurement microscope to determine the ablation efficiency. Different values of fluence, scanning line spacing and ablation depth were used to assess the effects of each variable on ablation efficiency. Ablation efficiencies for enamel and dentin were maximized at different laser fluences and number of scanning lines and decreased with increases in laser fluence or with increases in scanning line spacing beyond spot diameter or with increases in ablation depth. Laser fluence, scanning line spacing and ablation depth all significantly affected femtosecond laser ablation efficiency. Use of a reasonable control for each of these parameters will improve future clinical application.

Changes in quality of life over 1 year in patients with head and neck cancer.

PubMed

Ronis, David L; Duffy, Sonia A; Fowler, Karen E; Khan, Mumtaz J; Terrell, Jeffrey E

2008-03-01

To characterize and compare quality of life (QOL) in patients with head and neck cancer shortly before initial treatment and 1 year later and to study the predictors of changes in QOL over 1 year. Prospective cohort study. Three otolaryngology clinics. Three hundred sixteen patients having newly diagnosed squamous cell head and neck cancer. Health-related QOL was assessed using the 36-item Short-Form Health Survey and a head and neck cancer-specific QOL scale. Over 1 year, QOL decreased for physical functioning measures and eating but improved for mental health QOL. Depression and smoking were major predictors of poor QOL at baseline. Major predictors of change in QOL from baseline to 1 year were treatment factors, especially feeding tube placement (9 scales), chemotherapy (3 scales), and radiation therapy (3 scales). Baseline smoking and depressive symptoms also remained significant predictors of several QOL scales at 1 year. Health-related physical QOL tended to decline over 1 year and mental health QOL improved. The major predictors of change in QOL were treatment factors, smoking, and depressive symptoms. Physicians should alert patients to the relative effects on QOL one may experience with different treatments.

Neural correlates for angular head velocity in the rat dorsal tegmental nucleus

NASA Technical Reports Server (NTRS)

Bassett, J. P.; Taube, J. S.; Oman, C. M. (Principal Investigator)

2001-01-01

Many neurons in the rat lateral mammillary nuclei (LMN) fire selectively in relation to the animal's head direction (HD) in the horizontal plane independent of the rat's location or behavior. One hypothesis of how this representation is generated and updated is via subcortical projections from the dorsal tegmental nucleus (DTN). Here we report the type of activity in DTN neurons. The majority of cells (75%) fired as a function of the rat's angular head velocity (AHV). Cells exhibited one of two types of firing patterns: (1) symmetric, in which the firing rate was positively correlated with AHV during head turns in both directions, and (2) asymmetric, in which the firing rate was positively correlated with head turns in one direction and correlated either negatively or not at all in the opposite direction. In addition to modulation by AHV, some of the AHV cells (40.1%) were weakly modulated by the rat's linear velocity, and a smaller number were modulated by HD (11%) or head pitch (15.9%). Autocorrelation analyses indicated that with the head stationary, AHV cells displayed irregular discharge patterns. Because afferents from the DTN are the major source of information projecting to the LMN, these results suggest that AHV information from the DTN plays a significant role in generating the HD signal in LMN. A model is proposed showing how DTN AHV cells can generate and update the LMN HD cell signal.

US-guided percutaneous radiofrequency thermal ablation for the treatment of solid benign hyperfunctioning or compressive thyroid nodules.

PubMed

Deandrea, Maurilio; Limone, Paolo; Basso, Edoardo; Mormile, Alberto; Ragazzoni, Federico; Gamarra, Elena; Spiezia, Stefano; Faggiano, Antongiulio; Colao, Annamaria; Molinari, Filippo; Garberoglio, Roberto

2008-05-01

The aim of the study was to define the effectiveness and safety of ultrasound-guided percutaneous radiofrequency (RF) thermal ablation in the treatment of compressive solid benign thyroid nodules. Thirty-one patients not eligible for surgery or radioiodine (131I) treatment underwent RF ablation for benign nodules; a total of 33 nodules were treated (2 patients had 2 nodules treated in the same session): 10 cold nodules and 23 hyperfunctioning. Fourteen patients complained of compressive symptoms. Nodule volume, thyroid function and compressive symptoms were evaluated before treatment and at 1, 3 and 6 mo. Ultrasound-guided RF ablation was performed using a Starbust RITA needle, with nine expandable prongs; total exposure time was 6 to 10 min at 95 degrees C in one area or more of the nodule. Baseline volume (measured at the time of RF ablation) was 27.7 +/- 21.5 mL (mean +/- SD), but significantly decreased during follow-up: 19.2 +/- 16.2 at 1 mo (-32.7%; p < 0.001), 15.9 +/- 14.1 mL at 3 mo (-46.4 %; p < 0.001) and 14.6 +/- 12.6 mL at 6 mo (-50.7%; p < 0.001). After treatment, all patients with cold nodules remained euthyroid: five patients with hot nodules normalized thyroid function, and the remaining sixteen showed a partial remission of hyperthyroidism. Besides a sensation of heat and mild swelling of the neck, no major complications were observed. Improvement in compressive symptoms was reported by 13 patients, with a reduction on severity scale from 6.1 +/- 1.4 to 2.2 +/- 1.9 (p < 0.0001). Radiofrequency was effective and safe in reducing volume by about 50% and compressive symptoms in large benign nodules. Hyperfunction was fully controlled in 24% of patients and partially reduced in the others.

Ex vivo human bile duct radiofrequency ablation with a bipolar catheter.

PubMed

Atar, Mustafa; Kadayifci, Abdurrahman; Daglilar, Ebubekir; Hagen, Catherine; Fernandez-Del Castillo, Carlos; Brugge, William R

2018-06-01

Management of the primary and secondary tumors of the bile ducts still remains as a major clinical challenge. Radiofrequency (RF) ablation (RFA) of these tumors is feasible but the effect of RF energy on the human common bile duct (CBD) and surrounding tissues has not been investigated. This pilot study aimed to determine the relationship between RF energy and the depth of ablation in the normal human CBD. The study was performed on fresh ex vivo human biliary-pancreatic tissue which had been resected for a pancreatic cyst or mass. The study was conducted within 15 min after resection. A bipolar Habib RFA catheter was placed into the middle of the intact CBD, and three different (5, 7, 10 W) power settings were applied over a 90-s period by an RF generator. Gross and histological examinations were performed. The depth of coagulation necrosis in CBD and the effect of RFA on CBD wall and surrounding pancreas tissue were determined by microscopic examination. The study included eight tissue samples. 5 W power was applied to three sites and RFA caused only focal epithelial necrosis limited to the CBD mucosa. 7 and 10 W were applied to five sites and coagulation necrosis occurred in all cases. Microscopically, necrosis was transmural, involved accessory bile duct glands, and extended to the surrounding pancreatic tissue in four of these cases. Macroscopically, RFA resulted in circumferential white-yellowish color change extending approximately 2 cm of the CBD. Bipolar RF energy application with 5 W resulted in limited ablation on CBD wall. However, 7 and 10 W generated tissue necrosis which extended through the CBD wall and into surrounding pancreas tissue. Endoscopic biliary RFA is an effective technique for local biliary tissue ablation but the use of high energy may injure surrounding tissue.

Colloid cyst mimicking intracranial hemorrhage after head trauma.

PubMed

Buyukkaya, Ayla; Buyukkaya, Ramazan; Özel, Mehmet Ali; Sarıtas, Ayhan

2015-02-01

Trauma patients consist vast majority of the patients who admit to emergency department, and most of them have a head trauma. A 58-year-old patient was taken to emergency department with head trauma, and a hyperdense lesion neighboring to third ventricle was detected. A diagnosis of colloid cyst was made in the patient who was being followed up for hemorrhage. In patients with head trauma, colloid cyst may easly be confused with intracranial hemorrhage due to hyperdensity. The aim of this report is to emphasize the importance of clinical thinking in the differential diagnosis of hyperdense lesion on computed tomography imaging of a patient with head injury.

The use of microwaves ablation in the treatment of epiphyseal osteoid osteomas.

PubMed

Basile, Antonio; Failla, Giovanni; Reforgiato, Angelo; Scavone, Giovanni; Mundo, Elena; Messina, Martina; Caltabiano, Giuseppe; Arena, Francesco; Ricceri, Viola; Scavone, Antonio; Masala, Salvatore

2014-06-01

This study was designed to demonstrate the feasibility and the reliability of microwave ablation (MWA) of epiphyseal osteoid osteomas (OO). From February to November 2012, 7 patients (4 males and 3 females; age range 16-30 years) with epiphyseal OOs were treated with MWA. The treatment was performed with 16 G antennas with a power of 20 W for 2 min. The OOs were approached by using coaxial needles inserted with hammer or with automatic drill. All patients underwent spinal anaesthesia, with posttreatment 6-8 h observation before discharging. We treated epiphyseal OOs placed away from nervous and vascular nontarget structures, located in: femoral head (n = 2), femoral lesser trochanter (n = 2), femoral neck (n = 2), and proximal tibial epiphysis (n = 1). CT was used to visualize the nidus and to insert the needle for thermal ablation and for postprocedure control. Technical success was considered the positioning of the antenna in the nidus, while the efficacy of treatment was clinically evaluated as the complete remission of pain after the procedure by using the visual analogue score (VAS). Follow-up was performed by using VAS score 1 day, 1 week, and 1, 3, and 6 months after the procedure, whereas MRI examination was performed immediately after the procedure, at 1 month, and in any case of recurrence. Complications were also recorded. All patients experienced resolution of the symptomatology (VAS = 0) in ~1 week until the last follow-up, with residual VAS < 2 points occurring only from 1 to 7 days after the procedure. No intraprocedural complication was noted, whereas one patient had back pain for 2 months after the procedure, likely due to spinal analgesic injection. In our experience, MWA can be safely performed with excellent results without complications in selected cases of epiphyseal OOs; however, the clinical significance of this report is limited because there were only few patients included in this study. Thus, these data must be confirmed by further and larger studies.

Current Laser Resurfacing Technologies: A Review that Delves Beneath the Surface

PubMed Central

Preissig, Jason; Hamilton, Kristy; Markus, Ramsey

2012-01-01

Numerous laser platforms exist that rejuvenate the skin by resurfacing its upper layers. In varying degrees, these lasers improve the appearance of lentigines and rhytides, eliminate photoaging, soften scarring due to acne and other causes, and treat dyspigmentation. Five major classes of dermatologic lasers are currently in common use: ablative and nonablative lasers in both fractionated and unfractionated forms as well as radiofrequency technologies. The gentler nonablative lasers allow for quicker healing, whereas harsher ablative lasers tend to be more effective. Fractionating either laser distributes the effect, increasing the number of treatments but minimizing downtime and complications. In this review article, the authors seek to inform surgeons about the current laser platforms available, clarify the differences between them, and thereby facilitate the identification of the most appropriate laser for their practice. PMID:23904818

[Clinical study on patients with renal-cell carcinoma accompanied with Von Hippel-Lindau disease treated with radiofrequency ablation].

PubMed

Nao, Tomoya; Shimamoto, Tsutomu; Karashima, Takashi; Kamei, Maiko; Fukuhara, Hideo; Fukata, Satoshi; Satake, Hirofumi; Ashida, Shingo; Yamasaki, Ichiro; Kamata, Masayuki; Inoue, Keiji; Yamanishi, Tomoaki; Ogawa, Yasuhiro; Ito, Satoshi; Shuin, Taro

2014-09-01

We report 12 renal cell carcinomas in 6 patients with Von Hippel-Lindau (VHL) disease treated with radiofrequency ablation (RFA). The mean age of the patients was 46 (range 38-53) years (male : 4, female : 2). Computed tomography (CT)-guided transcutaneous RFA was performed under conscious sedation with local anesthetics. The mean size of the tumors was 2.4 (range 0.7-8.1) cm. Nine of the 12 tumors (75%) were locally well controlled. However, 3 tumors in 2 patients developed visceral metastases after RFA. While minimal flank pain, nausea, perinephritic hematoma and lumbago were observed, there was no major complication during or after the procedure. The therapy with CT-guided transcutaneous RFA is efficient and minimal invasive for renal cell carcinoma in patients with VHL, leading to preservation of renal function.

Ablation properties of carbon/carbon composites with tungsten carbide

NASA Astrophysics Data System (ADS)

Yin, Jian; Zhang, Hongbo; Xiong, Xiang; Huang, Baiyun; Zuo, Jinlv

2009-02-01

The ablation properties and morphologies of carbon/carbon (C/C) composites with tungsten carbide (WC) filaments were investigated by ablation test on an arc heater and scanning electron microscopy. And the results were compared with those without tungsten carbide (WC) filaments tested under the same conditions. It shows that there is a big difference between C/C composites with and without WC filaments on both macroscopic and microscopic ablation morphologies and the ablation rates of the former are higher than the latter. It is found that the ablation process of C/C composites with WC filaments includes oxidation of carbon fibers, carbon matrices and WC, melting of WC and WO 3, and denudation of WC, WO 3 and C/C composites. Oxidation and melting of WC leads to the formation of holes in z directional carbon fiber bundles, which increases the coarseness of the ablation surfaces of the composites, speeds up ablation and leads to the higher ablation rate. Moreover, it is further found that the molten WC and WO 3 cannot form a continuous film on the ablation surface to prevent further ablation of C/C composites.

MANAGEMENT OF ENDOCRINE DISEASE: Arguments for the prolonged use of antithyroid drugs in children with Graves' disease.

PubMed

Léger, Juliane; Carel, Jean-Claude

2017-08-01

Graves' disease is an autoimmune disorder. It is the leading cause of hyperthyroidism, but is rare in children. Patients are initially managed with antithyroid drugs (ATDs), such as methimazole/carbimazole. A major disadvantage of treatment with ATD is the high risk of relapse, exceeding 70% of children treated for duration of 2 years, and the potential major side effects of the drug reported in exceptional cases. The major advantage of ATD treatment is that normal homeostasis of the hypothalamus-pituitary-thyroid axis may be restored, with periods of drug treatment followed by freedom from medical intervention achieved in approximately 40-50% of cases after prolonged treatment with ATD, for several years, in recent studies. Alternative ablative treatments such as radioactive iodine and, less frequently and mostly in cases of very high volume goiters or in children under the age of 5 years, thyroidectomy, performed by pediatric surgeons with extensive experience should be proposed in cases of non-compliance, intolerance to medical treatment or relapse after prolonged medical treatment. Ablative treatments are effective against hyperthyroidism, but they require the subsequent administration of levothyroxine throughout the patient's life. This review considers data relating to the prognosis for Graves' disease remission in children and explores the limitations of study designs and results; and the emerging proposal for management through the prolonged use of ATD drugs. © 2017 European Society of Endocrinology.

Sorting Potatoes for Miss Bonner.

ERIC Educational Resources Information Center

Herreid, Clyde Freeman

1998-01-01

Discusses the basis of a classification scheme for types of case studies. Four major classification headings are identified: (1) individual assignment; (2) lecture; (3) discussion; and (4) small group activities. Describes each heading from the point of view of several teaching methods. (DDR)

Experimental- Analitical Procedure Of Definition Of Thermal Fluxes On The Head Fairing Of Launch Vehicles

NASA Astrophysics Data System (ADS)

Yurchenko, I.; Karakotin, I.; Kudinov, A.

2011-05-01

Minimization of head fairing heat protection shield weight during spacecraft injecting in atmosphere dense layers is a complicated task. The identification of heat transfer coefficient on heat protection shield surface during injection can be considered as a primary task to be solved with certain accuracy in order to minimize heat shield weight as well as meet reliability requirements. The height of the roughness around sound point on the head fairing spherical nose tip has a great influence on the heat transfer coefficient calculation. As it has found out during flight tests the height of the roughness makes possible to create boundary layer transition criterion on the head fairing in flight. Therefore the second task is an assessment how height of the roughness influences on the total incoming heat flux to the head fairing. And finally the third task is associated with correct implementation of the first task results, as there are changing boundary conditions during a flight such as bubbles within heat shield surface paint and thermal protection ablation for instance. In the article we have considered results of flight tests carried out using launch vehicles which allowed us to measure heat fluxes in flight and to estimate dispersions of heat transfer coefficient. The experimental-analytical procedure of defining heat fluxes on the LV head fairings has been presented. The procedure includes: - calculation of general-purpose dimensionless heat transfer coefficient - Nusselt number Nueff - based on the proposed effective temperature Teff method. The method allows calculate the Nusselt number values for cylindrical surfaces as well as dispersions of heat transfer coefficient; - universal criterion of turbulent-laminar transition for blunted head fairings - Reynolds number Reek = [ρеUеk/μе]TR = const , which gives the best correlation of all dates of flight experiment carried out per Reda procedure to define turbulent-laminar transition in boundary layer. The criterion allows defining time margins when turbulent flux on space head surfaces exists. It was defined that in conditions when high background disturbances of free stream flux while main LV engines operating join with integrated roughness influence the critical value of Reynolds number is an order-diminished value compared to values obtained in wind tunnels and in free flight. Influence of minimization of height of surface roughness near sound point on head fairing nose has been estimated. It has been found that the criterion of turbulent-laminar transition for smooth head fairings elements - Reynolds number - reaches the limit value which is equal to 200. This value is obtained from momentum thickness Reynolds number when roughness height is close to zero. So the turbulent- laminar flux transition occurs earlier with decreased duration of effect of high turbulent heat fluxes to the heat shield. This will allow decreasing head shield thickness up to 30%

Study on ablation behavior of silicone rubber based insulation material under the condition of boron oxide particles erosion

NASA Astrophysics Data System (ADS)

Zha, B. L.; Shi, Y. A.; Wang, J. J.; Su, Q. D.

2018-01-01

Self-designed oxygen-kerosene ablation system was employed to study the ablation characteristics of silicone rubber based thermal insulation materials under the condition of boron oxide particles erosion. The ablation test was designed with a mass fraction of 1.69% boron oxide particles and particles-free, the microstructure and elemental analysis of the specimens before and after ablation were carried out by Scanning Electron Microscopy (SEM) and Energy Dispersion Spectrum (EDS). Experiment results show that the average mass ablation rate of the materials was 0.0099 g•s-1 and the average ablation rate was -0.025 mm•s-1 under the condition of pure gas phase ablation; and the average mass ablation rate of the multiphase ablation test group was 0.1775 g•s-1, whose average ablation rate was 0.437 mm•s-1 during the ablation process, the boron oxide particles would adhere a molten layer on the flame contact surface of the specimen, which covering the pores on the material surface, blocking the infiltration channel for the oxidizing component and slowing down the oxidation loss rate of the material below the surface, but because the particles erosion was the main reason for material depletion, the combined effect of the above both led to the upward material ablation rates of Silicone Rubber.

High spatial resolution analysis of ferromanganese concretions by LA-ICP-MS†

PubMed Central

Axelsson, Mikael D; Rodushkin, Ilia; Baxter, Douglas C; Ingri, Johan; Öhlander, Björn

2002-01-01

A procedure was developed for the determination of element distributions in cross-sections of ferromanganese concretions using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The effects of carrier flow rates, rf forward power, ablation energy, ablation spot size, repetition rate and number of shots per point on analyte intensity were studied. It is shown that different carrier gas flow rates are required in order to obtain maximum sensitivities for different groups of elements, thus complicating the optimisation of ICP parameters. On the contrary, LA parameters have very similar effects on almost all elements studied, thus providing a common optimum parameter set for the entire mass range. However, for selected LA parameters, the use of compromise conditions was necessary in order to compensate for relatively slow data acquisition by ICP-MS and maintain high spatial resolution without sacrificing the multielemental capabilities of the technique. Possible variations in ablation efficiency were corrected for mathematically using the sum of Fe and Mn intensities. Quantification by external calibration against matrix-matched standards was successfully used for more than 50 elements. These standards, in the form of pressed pellets (no binder), were prepared in-house using ferromanganese concentrates from a deep-sea nodule reference material as well as from shallow-marine concretions varying in size and having different proportions of three major phases: aluminosilicates, Fe- and Mn-oxyhydroxides. Element concentrations in each standard were determined by means of conventional solution nebulisation ICP-MS following acid digestion. Examples of selected inter-element correlations in distribution patterns along the cross-section of a concretion are given.

Value of percutaneous radiofrequency ablation with or without percutaneous vertebroplasty for pain relief and functional recovery in painful bone metastases.

PubMed

Clarençon, Frédéric; Jean, Betty; Pham, Hang-Phuong; Cormier, Evelyne; Bensimon, Gilbert; Rose, Michèle; Maksud, Philippe; Chiras, Jacques

2013-01-01

To evaluate the effectiveness of percutaneous radiofrequency (RF) ablation with or without percutaneous vertebroplasty (PV) on pain relief, functional recovery and local recurrence at 6 months' follow-up (FU), in patients with painful osseous metastases. Thirty RF ablations were performed in 24 patients (mean age: 61 years) with bone metastases. Half of the patients had an additional PV. The primary end point was pain relief evaluated by a visual analogue scale (VAS) before treatment, and at 1 and 6 months' FU. Functional outcome was assessed according to the evolution of their ability to walk at 6 months' FU. Imaging FU was available in 20 out of 24 patients with a mean delay of 4.7 months. Reduction of pain was obtained at 6 months FU in 81% of cases (15 out of 18). Mean pretreatment VAS was 6.4 (±2.7). Mean VAS was 1.9 (±2.4) at 1 month FU, and 2.3 (±2.9) at 6 months' FU. Pain was significantly reduced at 6 months FU (mean VAS reduction = 4.1; P < 0.00001). Functional improvement was obtained in 74% of the cases. Major complications rate was 12.5 % (3 out of 24) with 2 skin burns, and 1 case of myelopathy. Local tumour recurrence or progression was recorded in 5 cases. Radiofrequency ablation is an effective technique in terms of pain relief and functional recovery for the treatment of bone metastases, which provides a relatively low rate of local recurrence.

Bimodal electric tissue ablation (BETA) - in-vivo evaluation of the effect of applying direct current before and during radiofrequency ablation of porcine liver.

PubMed

Cockburn, J F; Maddern, G J; Wemyss-Holden, S A

2007-03-01

To examine the effect of applying increasing amounts of direct current (DC) before and during alternating current radiofrequency ablation of porcine liver. Using a Radiotherapeutics RF3000 generator, a 9 V AC/DC transformer and a 16 G plain aluminium tube as an electrode, a control group of 24 porcine hepatic radiofrequency ablation zones was compared with 24 zones created using a bimodal electric tissue ablation (BETA) technique in three pigs. All ablations were terminated when tissue impedance rose to greater than 999 Omega or radiofrequency energy input fell below 5 W on three successive measurements taken at 1 min intervals. BETA ablations were performed in two phases: an initial phase of variable duration DC followed by a second phase during which standard radiofrequency ablation was applied simultaneously with DC. During this second phase, radiofrequency power input was regulated by the feedback circuitry of the RF3000 generator according to changes in tissue impedance. The diameters (mm) of each ablation zone were measured by two observers in two planes perpendicular to the plane of needle insertion. The mean short axis diameter of each ablation zone was subjected to statistical analysis. With increased duration of prior application of DC, there was a progressive increase in the diameter of the ablation zone (p<0.001). This effect increased sharply up to 300 s of pre-treatment after which a further increase in diameter occurred, but at a much lesser rate. A maximum ablation zone diameter of 32 mm was produced (control diameters 10-13 mm). Applying a 9 V DC to porcine liver in vivo, and continuing this DC application during subsequent radiofrequency ablation, results in larger ablation zone diameters compared with radiofrequency ablation alone.

Sequential high intensity focused ultrasound (HIFU) ablation in the treatment of benign multinodular goitre: an observational retrospective study.

PubMed

Lang, Brian H H; Woo, Yu-Cho; Chiu, Keith Wan-Hang

2018-03-19

Assessing the efficacy and safety of sequential high-intensity focused ultrasound (HIFU) ablation in a multinodular goitre (MNG) by comparing them with single HIFU ablation. One hundred and four (84.6%) patients underwent single ablation of a single nodule (group I), while 19 (15.4%) underwent sequential ablation of two relatively-dominant nodules in a MNG (group II). Extent of shrinkage per nodule [by volume reduction ratio (VRR)], pain scores (by 0-10 visual analogue scale) during and after ablation, and rate of vocal cord palsy (VCP), skin burn and nausea/vomiting were compared between the two groups. All 19 (100%) sequential ablations completed successfully. The 3- and 6-month VRR of each nodule were comparable between the two groups (p > 0.05) and in group II, the 3- and 6-month VRR between the first and second nodules were comparable (p = 0.710 and p = 0.548, respectively). Pain score was significantly higher in group II in the morning after ablation (2.29 vs 1.15, p = 0.047) and nausea/vomiting occurred significantly more frequently in group II (15.8% vs 0.0%, p = 0.012). However, VCP and skin burn were comparable (p > 0.05). Sequential ablation had comparable efficacy and safety as single ablation. However, patients undergoing sequential ablation are at higher likelihood of pain in the following morning and nausea/vomiting after ablation. • Sequential HIFU ablation is well-tolerated in patients with two dominant thyroid nodules • More pain is experienced in the morning following sequential HIFU ablation • More nausea/vomiting is experienced following sequential HIFU ablation.

Histopathology of breast cancer after magnetic resonance-guided high-intensity focused ultrasound and radiofrequency ablation.

PubMed

Knuttel, Floortje M; Waaijer, Laurien; Merckel, Laura G; van den Bosch, Maurice A A J; Witkamp, Arjen J; Deckers, Roel; van Diest, Paul J

2016-08-01

Magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) ablation and radiofrequency ablation (RFA) are being researched as possible substitutes for surgery in breast cancer patients. The histopathological appearance of ablated tissue has not been studied in great detail. This study aimed to compare histopathological features of breast cancer after MR-HIFU ablation and RFA. MR-HIFU ablation and RFA were performed in- and ex-vivo. Tumours in six mastectomy specimens were partially ablated with RFA or MR-HIFU. In-vivo MR-HIFU ablation was performed 3-6 days before excision; RFA was performed in the operation room. Tissue was fixed in formalin and processed to haematoxylin and eosin (H&E) and cytokeratin-8 (CK-8)-stained slides. Morphology and cell viability were assessed. Ex-vivo ablation resulted in clear morphological changes after RFA versus subtle differences after MR-HIFU. CK-8 staining was decreased or absent. H&E tended to underestimate the size of thermal damage. In-vivo MR-HIFU resulted in necrotic-like changes. Surprisingly, some ablated lesions were CK-8-positive. Histopathology after in-vivo RFA resembled ex-vivo RFA, with hyper-eosinophilic stroma and elongated nuclei. Lesion borders were sharp after MR-HIFU and indistinct after RFA. Histopathological differences between MR-HIFU-ablated tissue and RF-ablated tissue were demonstrated. CK-8 was more reliable for cell viability assessment than H&E when used directly after ablation, while H&E was more reliable in ablated tissue left in situ for a few days. Our results contribute to improved understanding of histopathological features in breast cancer lesions treated with minimally invasive ablative techniques. © 2016 John Wiley & Sons Ltd.

Performance of Er:YAG laser ablation of hard bone under different irrigation water cooling conditions

NASA Astrophysics Data System (ADS)

Beltrán Bernal, Lina M.; Shayeganrad, Gholamreza; Kosa, Gabor; Zelechowski, Marek; Rauter, Georg; Friederich, Niklaus; Cattin, Philippe C.; Zam, Azhar

2018-02-01

The biological applicability of the Erbium-doped Yttrium Aluminum Garnet (Er:YAG) laser in surgical processes is so far limited to hard dental tissues. Using the Er:YAG laser for bone ablation is being studied since it has shown good performance for ablating dental hard tissues at the wavelength 2.94 μm, which coincides with the absorption peak of water, one of the main components of hard tissue, like teeth and bone. To obtain a decent performance of the laser in the cutting process, we aim at examining the influence of sequenced water jet irrigation on both, the ablation rate and the prevention of carbonization while performing laser ablation of bone with fixed laser parameters. An Er:YAG laser at 2.94 μm wavelength, 940 mJ energy per pulse, 400 μs pulse width, and 10 Hz repetition rate is used for the ablation of a porcine femur bone under different pulsed water jet irrigation conditions. We used micro-computed tomography (micro-CT) scans to determine the geometry of the ablated areas. In addition, scanning electron microscopy (SEM) is used for qualitative observations for the presence of carbonization and micro-fractures on the ablated surfaces. We evaluate the performance of the laser ablation process for the different water jet conditions in terms of the ablation rate, quantified by the ablated volume per second and the ablation efficiency, calculated as the ablated volume per pulse energy. We provide an optimized system for laser ablation which delivers the appropriate amount of water to the bone and consequently, the bone is ablated in the most efficient way possible without carbonization.

Robotically assisted ablation produces more rapid and greater signal attenuation than manual ablation.

PubMed

Koa-Wing, Michael; Kojodjojo, Pipin; Malcolme-Lawes, Louisa C; Salukhe, Tushar V; Linton, Nick W F; Grogan, Aaron P; Bergman, Dale; Lim, Phang Boon; Whinnett, Zachary I; McCarthy, Karen; Ho, Siew Yen; O'Neill, Mark D; Peters, Nicholas S; Davies, D Wyn; Kanagaratnam, Prapa

2009-12-01

Robotic remote catheter ablation potentially provides improved catheter-tip stability, which should improve the efficiency of radiofrequency energy delivery. Percentage reduction in electrogram peak-to-peak voltage has been used as a measure of effectiveness of ablation. We tested the hypothesis that improved catheter-tip stability of robotic ablation can diminish signals to a greater degree than manual ablation. In vivo NavX maps of 7 pig atria were constructed. Separate lines of ablation were performed robotically and manually, recording pre- and postablation peak-to-peak voltages at 10, 20, 30, and 60 seconds and calculating signal amplitude reduction. Catheter ablation settings were constant (25W, 50 degrees , 17 mL/min, 20-30 g catheter tip pressure). The pigs were sacrificed and ablation lesions correlated with NavX maps. Robotic ablation reduced signal amplitude to a greater degree than manual ablation (49 +/- 2.6% vs 29 +/- 4.5% signal reduction after 1 minute [P = 0.0002]). The mean energy delivered (223 +/- 184 J vs 231 +/- 190 J, P = 0.42), power (19 +/- 3.5 W vs 19 +/- 4 W, P = 0.84), and duration of ablation (15 +/- 9 seconds vs 15 +/- 9 seconds, P = 0.89) was the same for manual and robotic. The mean peak catheter-tip temperature was higher for robotic (45 +/- 5 degrees C vs 42 +/- 3 degrees C [P < 0.0001]). The incidence of >50% signal reduction was greater for robotic (37%) than manual (21%) ablation (P = 0.0001). Robotically assisted ablation appears to be more effective than manual ablation at signal amplitude reduction, therefore may be expected to produce improved clinical outcomes.

Carbon Dioxide Laser Ablation of Basal Cell Carcinoma with Visual Guidance by Reflectance Confocal Microscopy: A Proof of Principle Pilot Study

PubMed Central

Hibler, B.P.; Sierra, H.; Cordova, M.; Phillips, W.; Rajadhyaksha, M.; Nehal, K.S.; Rossi, A.M.

2016-01-01

Background Laser ablation is an alternative, non-surgical treatment modality for low-risk basal cell carcinoma (BCC); however, lack of confirmative tumour destruction or residual tumour presence has been a limiting factor to adoption. Reflectance confocal microscopy (RCM) provides non-invasive, cellular-level resolution imaging of the skin and is capable of identifying tumour. Objective To evaluate the use of RCM to guide carbon dioxide (CO2) laser ablation of BCC, confirm destruction, and correlate findings with histology. Methods RCM was used pre-ablation to evaluate for features of BCC. Ablation was performed with a CO2 laser, and the response rapidly assessed using handheld RCM to evaluate for residual tumour. Confirmative pathology was used to verify confocal imaging. Results RCM imaging identified tumour pre-ablation with features not identified on normal, surrounding skin. Post-ablation, RCM documented complete removal of tumour in six cases and residual tumour in two. Histologic examination identified the ablated area and confirmed clearance of tumour in the six aforementioned cases and corroborated confocal findings for residual tumour in the other two cases. Conclusions We report successful treatment of superficial and nodular BCC using CO2 laser ablation augmented by RCM imaging for pre-ablation guidance and verification of tumour removal post-ablation. Akin to complete circumferential and deep margin control techniques, using RCM helps to map peripheral and deep BCC margins to hone in on areas exhibiting persistent tumour after ablation. CO2 laser ablation visually guided by RCM can help circumvent previously cited limiting factors of laser ablation for tumour destruction by providing cellular-level resolution imaging of tumour and margin assessment in between each laser pass and post-ablation. PMID:26800657

Diagnostic Discrepancies in Mandatory Slide Review of Extradepartmental Head and Neck Cases: Experience at a Large Academic Center.

PubMed

Mehrad, Mitra; Chernock, Rebecca D; El-Mofty, Samir K; Lewis, James S

2015-12-01

Medical error is a significant problem in the United States, and pathologic diagnoses are a significant source of errors. Prior studies have shown that second-opinion pathology review results in clinically major diagnosis changes in approximately 0.6% to 5.8% of patients. The few studies specifically on head and neck pathology have suggested rates of changed diagnoses that are even higher. Objectives .- To evaluate the diagnostic discrepancy rates in patients referred to our institution, where all such cases are reviewed by a head and neck subspecialty service, and to identify specific areas with more susceptibility to errors. Five hundred consecutive, scanned head and neck pathology reports from patients referred to our institution were compared for discrepancies between the outside and in-house diagnoses. Major discrepancies were defined as those resulting in a significant change in patient clinical management and/or prognosis. Major discrepancies occurred in 20 cases (4% overall). Informative follow-up material was available on 11 of the 20 patients (55.0%), among whom, the second opinion was supported in 11 of 11 cases (100%). Dysplasia versus invasive squamous cell carcinoma was the most common (7 of 20; 35%) area of discrepancy, and by anatomic subsite, the sinonasal tract (4 of 21; 19.0%) had the highest rate of discrepant diagnoses. Of the major discrepant diagnoses, 12 (12 of 20; 60%) involved a change from benign to malignant, one a change from malignant to benign (1 of 20; 5%), and 6 involved tumor classification (6 of 20; 30%). Head and neck pathology is a relatively high-risk area, prone to erroneous diagnoses in a small fraction of patients. This study supports the importance of second-opinion review by subspecialized pathologists for the best care of patients.

Dynamical analysis of surface-insulated planar wire array Z-pinches

NASA Astrophysics Data System (ADS)

Li, Yang; Sheng, Liang; Hei, Dongwei; Li, Xingwen; Zhang, Jinhai; Li, Mo; Qiu, Aici

2018-05-01

The ablation and implosion dynamics of planar wire array Z-pinches with and without surface insulation are compared and discussed in this paper. This paper first presents a phenomenological model named the ablation and cascade snowplow implosion (ACSI) model, which accounts for the ablation and implosion phases of a planar wire array Z-pinch in a single simulation. The comparison between experimental data and simulation results shows that the ACSI model could give a fairly good description about the dynamical characteristics of planar wire array Z-pinches. Surface insulation introduces notable differences in the ablation phase of planar wire array Z-pinches. The ablation phase is divided into two stages: insulation layer ablation and tungsten wire ablation. The two-stage ablation process of insulated wires is simulated in the ACSI model by updating the formulas describing the ablation process.

Epidemiology and Molecular Biology of Head and Neck Cancer.

PubMed

Jou, Adriana; Hess, Jochen

2017-01-01

Head and neck cancer is a common and aggressive malignancy with a high morbidity and mortality profile. Although the large majority of cases resemble head and neck squamous cell carcinoma (HNSCC), the current classification based on anatomic site and tumor stage fails to capture the high level of biologic heterogeneity, and appropriate clinical management remains a major challenge. Hence, a better understanding of the molecular biology of HNSCC is urgently needed to support biomarker development and personalized care for patients. This review focuses on recent findings based on integrative genomics analysis and multi-scale modeling approaches and how they are beginning to provide more sophisticated clues as to the biological and clinical diversity of HNSCC. © 2017 S. Karger GmbH, Freiburg.

Ventricular fibrillation occurring after atrioventricular node ablation despite minimal difference between pre- and post-ablation heart rates.

PubMed

Squara, F; Theodore, G; Scarlatti, D; Ferrari, E

2017-02-01

We report the case of an 82-year-old man presenting with ventricular fibrillation (VF) occurring acutely after atrioventricular node (AVN) ablation. This patient had severe valvular cardiomyopathy, chronic atrial fibrillation (AF), and underwent prior to the AVN ablation a biventricular implantable cardiac defibrillator positioning. The VF was successfully cardioverted with one external electrical shock. What makes this presentation original is that the pre-ablation spontaneous heart rate in AF was slow (84 bpm), and that VF occurred after ablation despite a minimal heart rate drop of only 14 bpm. VF is the most feared complication of AVN ablation, but it had previously only been described in case of acute heart rate drop after ablation of at least 30 bpm (and more frequently>50 bpm). This case report highlights the fact that VF may occur after AVN ablation regardless of the heart rate drop, rendering temporary fast ventricular pacing mandatory whatever the pre-ablation heart rate. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Ablation of aluminum nitride films by nanosecond and femtosecond laser pulses

NASA Astrophysics Data System (ADS)

Gruzdev, Vitaly; Tzou, Robert; Salakhutdinov, Ildar; Danylyuk, Yuriy; McCullen, Erik; Auner, Gregory

2009-02-01

We present results of comparative study of laser-induced ablation of AlN films with variable content of oxygen as a surface-doping element. The films deposited on sapphire substrate were ablated by a single nanosecond pulse at wavelength 248 nm, and by a single femtosecond pulse at wavelength 775 nm in air at normal pressure. Ablation craters were inspected by AFM and Nomarski high-resolution microscope. Irradiation by nanosecond pulses leads to a significant removal of material accompanied by extensive thermal effects, chemical modification of the films around the ablation craters and formation of specific defect structures next to the craters. Remarkable feature of the nanosecond experiments was total absence of thermo-mechanical fracturing near the edges of ablation craters. The femtosecond pulses produced very gentle ablation removing sub-micrometer layers of the films. No remarkable signs of thermal, thermo-mechanical or chemical effects were found on the films after the femtosecond ablation. We discuss mechanisms responsible for the specific ablation effects and morphology of the ablation craters.

Highlights from the Second International Symposium on HPV infection in head and neck cancer.

PubMed

Wiegand, Susanne; Wichmann, G; Golusinski, W; Leemans, C R; Klussmann, J P; Dietz, A

2018-06-01

The Second International Symposium on HPV Infection in Head and Neck Cancer was held on 3rd-4th November 2016 in Leipzig, Germany. The meeting brought together researchers and clinicians to share the latest knowledge on HPV infection in head and neck cancer and to join active and constructive scientific discussions. This report summarizes the major themes discussed during the symposium.

On the design and test of a liquid injection electric thruster

NASA Technical Reports Server (NTRS)

Youmans, E. H.; Kenney, J. T.; Dahlgren, J. B.

1973-01-01

The design of the thruster described incorporates a coaxial four-segment trigger assembly to discharge a high-energy capacitor. The discharge ablates a waxy perfluorocarbon from the surface of porous annular metal ring, and the resulting plasma is electromagnetically accelerated to ambient producing thrust. Tests revealed a thruster performance well in excess of the major design goals.

TPS Ablator Technologies for Interplanetary Spacecraft

NASA Technical Reports Server (NTRS)

Curry, Donald M.

2004-01-01

This slide presentation reviews the status of Thermal Protection System (TPS) Ablator technologies and the preparation for use in interplanetary spacecraft. NASA does not have adequate TPS ablatives and sufficient selection for planned missions. It includes a comparison of shuttle and interplanetary TPS requirements, the status of mainline TPS charring ablator materials, a summary of JSC SBIR accomplishments in developing advanced charring ablators and the benefits of SBIR Ablator/fabrication technology.

Noninvasive Assessment of Tissue Heating During Cardiac Radiofrequency Ablation Using MRI Thermography

PubMed Central

Kolandaivelu, Aravindan; Zviman, Menekhem M.; Castro, Valeria; Lardo, Albert C.; Berger, Ronald D.; Halperin, Henry R.

2010-01-01

Background Failure to achieve properly localized, permanent tissue destruction is a common cause of arrhythmia recurrence after cardiac ablation. Current methods of assessing lesion size and location during cardiac radiofrequency ablation are unreliable or not suited for repeated assessment during the procedure. MRI thermography could be used to delineate permanent ablation lesions because tissue heating above 50°C is the cause of permanent tissue destruction during radiofrequency ablation. However, image artifacts caused by cardiac motion, the ablation electrode, and radiofrequency ablation currently pose a challenge to MRI thermography in the heart. In the current study, we sought to demonstrate the feasibility of MRI thermography during cardiac ablation. Methods and Results An MRI-compatible electrophysiology catheter and filtered radiofrequency ablation system was used to perform ablation in the left ventricle of 6 mongrel dogs in a 1.5-T MRI system. Fast gradient-echo imaging was performed before and during radiofrequency ablation, and thermography images were derived from the preheating and postheating images. Lesion extent by thermography was within 20% of the gross pathology lesion. Conclusions MR thermography appears to be a promising technique for monitoring lesion formation and may allow for more accurate placement and titration of ablation, possibly reducing arrhythmia recurrences. PMID:20657028

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

PubMed

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

2018-05-11

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

The Neural Crest in Cardiac Congenital Anomalies

PubMed Central

Keyte, Anna; Hutson, Mary Redmond

2012-01-01

This review discusses the function of neural crest as they relate to cardiovascular defects. The cardiac neural crest cells are a subpopulation of cranial neural crest discovered nearly 30 years ago by ablation of premigratory neural crest. The cardiac neural crest cells are necessary for normal cardiovascular development. We begin with a description of the crest cells in normal development, including their function in remodeling the pharyngeal arch arteries, outflow tract septation, valvulogenesis, and development of the cardiac conduction system. The cells are also responsible for modulating signaling in the caudal pharynx, including the second heart field. Many of the molecular pathways that are known to influence specification, migration, patterning and final targeting of the cardiac neural crest cells are reviewed. The cardiac neural crest cells play a critical role in the pathogenesis of various human cardiocraniofacial syndromes such as DiGeorge, Velocardiofacial, CHARGE, Fetal Alcohol, Alagille, LEOPARD, and Noonan syndromes, as well as Retinoic Acid Embryopathy. The loss of neural crest cells or their dysfunction may not always directly cause abnormal cardiovascular development, but are involved secondarily because crest cells represent a major component in the complex tissue interactions in the head, pharynx and outflow tract. Thus many of the human syndromes linking defects in the heart, face and brain can be better understood when considered within the context of a single cardiocraniofacial developmental module with the neural crest being a key cell type that interconnects the regions. PMID:22595346

Automated planning of ablation targets in atrial fibrillation treatment

NASA Astrophysics Data System (ADS)

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.

Thermal distribution of microwave antenna for atrial fibrillation catheter ablation.

PubMed

Zhang, Huijuan; Nan, Qun; Liu, Youjun

2013-09-01

The aim of this study is to investigate the effects of ablation parameters on thermal distribution during microwave atrial fibrillation catheter ablation, such as ablation time, ablation power, blood condition and antenna placement, and give proper ablative parameters to realise transmural ablation. In this paper, simplified 3D antenna-myocardium-blood finite element method models were built to simulate the endocardial ablation operation. Thermal distribution was obtained based on the coupled electromagnetic-thermal analysis. Under different antenna placement conditions and different microwave power inputs within 60 s, the lesion dimensions (maximum depth, maximum width) of the ablation zones were analysed. The ablation width and depth increased with the ablation time. The increase rate significantly slowed down after 10 s. The maximum temperature was located in 1 mm under the antenna tip when perpendicular to the endocardium, while 1.5 mm away from the antenna axis and 26 mm along the antenna (with antenna length about 30 mm) in the myocardium when parallel to the endocardium. The maximum temperature in the ablated area decreased and the effective ablation area (with the temperature raised to 50°C) shifted deeper into the myocardium due to the blood cooling. The research validated that the microwave antenna can provide continuous long and linear lesions for the treatment of atrial fibrillation. The dimensions of the created lesion widths were all larger than those of the depths. It is easy for the microwave antenna to produce transmural lesions for an atrial wall thickness of 2-6 mm by adjusting the applied power and ablation time.

Increase in pulmonary arterial pressure after atrial fibrillation ablation: incidence and associated findings.

PubMed

Witt, Chance M; Fenstad, Eric R; Cha, Yong-Mei; Kane, Garvan C; Kushwaha, Sudhir S; Hodge, David O; Asirvatham, Samuel J; Oh, Jae K; Packer, Douglas L; Powell, Brian D

2014-06-01

The stiff left atrial (LA) syndrome is defined as pulmonary hypertension (PH) secondary to reduced LA compliance and has recently been shown to be one cause of PH after atrial fibrillation (AF) ablation. We aimed to determine the incidence of an increase in pulmonary arterial (PA) pressure post-ablation and examine the clinical and echocardiographic associations. Patients who underwent AF ablation between 1999 and 2011 were included if they had both an echocardiogram pre-ablation and 3 months post-ablation. Patients were then separated into two groups with the increased PA pressure group defined as patients with >10 mmHg increase in right ventricular systolic pressure (RVSP) post-ablation and a post-ablation RVSP >35 mmHg. Of the 499 patients meeting the study criteria, 41 (8.2%) had an increase in RVSP >10 mmHg and RVSP >35 mmHg post-ablation. On echocardiogram, the two groups had similar E/A and E/e' ratios pre-ablation. However, post-ablation, the increased PA pressure group had higher E/A (2.12 vs. 1.49, p < 0.01) and E/e' (14.7 vs. 11.2, p < 0.01) ratios. LA expansion index values were lower in the increased PA pressure group pre-ablation (51 vs. 92%, p < 0.01), but not significantly different post-ablation (82 vs. 88%, p = 0.44). Around 8% of patients develop an increase in estimated PA pressure after AF ablation. Echocardiographic parameters suggest that patients who develop increased PA pressure are developing (or unmasking) left ventricular diastolic dysfunction.

Ablation of "Background Tachycardia" in Long Standing Atrial Fibrillation: Improving the Outcomes by Unmasking a Residual Atrial Fibrillation Perpetuator.

PubMed

Pachón-M, José Carlos; Pachón-M, Enrique I; Santillana P, Tomas G; Lobo, Tasso Julio; Pachón, Carlos Thiene C; Pachón-M, Juán Carlos; Albornoz V, Remy Nelson; Zerpa A, Juán Carlos; Ortencio, Felipe; Arruda, Mauricio

2017-01-01

Catheter ablation of long-standing persistent AF (LSAF) remains challenging. Since AF-Nest (AFN) description, we have observed that a stable, protected, fast source firing, namely "Background Tachycardia"(BT), could be hidden beneath the chaotic AF. Following pulmonary vein isolation (PVI)+AFN ablation one or more BT may arise or be induced in 30-40% of patients, which could be the culprit forAF maintenance and ablation recurrences. We studied 114 patients, from 322 sequential LSAF regular ablations, having spontaneous or induced residual BT after EGM-guided PVI+AFN ablation of LSAF; 55.6±11y/o, 97males (85.1%), EF=65.5±8%, LA=42.8±6.7mm. Macroreentrant tachycardias were excluded. Pre-ablationAF 12-leads ECG Digital processing(DP) and spectral analysis(SA) was performed searching for BT before AF ablation and its correlation with BT during ablation.After PVI, 38.1±9 AFN sites/patient and 135 sustained BTs (1-3, 1.2±0.5/patient) were ablated. BT cycle length(CL) was 246.3±37.3ms. In 79 patients presenting suitable DP for SA, the BT-CL was 241.6±34.3ms with intra procedure BT-CL correlation r=0.83/p<0.01. Following BT ablation, AF could not be induced. During FU of 13→60 months(22.8±12m), AF freedom for BT RF(+) vs. BT RF(-) groups were 77.9% vs. 56.4% (p=0.009), respectively. There was no significant complication. BT ablation following PVI and AFN ablation improved long-term outcomes ofLSAF ablation. BT is likely due to sustained microreentry, protected during AF by entry block. BT can be suspected by spectral analysis of the pre-ablation ECG and is likely one important AF perpetuator by causing electrical resonance of the AFN. This ablation strategy warrants randomized, multicenter investigation.

Dual beam optical system for pulsed laser ablation film deposition

DOEpatents

Mashburn, D.N.

1996-09-24

A laser ablation apparatus having a laser source outputting a laser ablation beam includes an ablation chamber having a sidewall, a beam divider for dividing the laser ablation beam into two substantially equal halves, and a pair of mirrors for converging the two halves on a surface of the target from complementary angles relative to the target surface normal, thereby generating a plume of ablated material emanating from the target. 3 figs.

Dual beam optical system for pulsed laser ablation film deposition

DOEpatents

Mashburn, Douglas N.

1996-01-01

A laser ablation apparatus having a laser source outputting a laser ablation beam includes an ablation chamber having a sidewall, a beam divider for dividing the laser ablation beam into two substantially equal halves, and a pair of mirrors for converging the two halves on a surface of the target from complementary angles relative to the target surface normal, thereby generating a plume of ablated material emanating from the target.

Ion acceleration enhanced by target ablation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, S.; State Key Laboratory of Nuclear Physics and Technology, and Key Lab of HEDPS, CAPT, Peking University, Beijing 100871; Institute of Radiation, Helmholtz-Zentrum Dresden-Rossendorf, 01314 Dresden

2015-07-15

Laser proton acceleration can be enhanced by using target ablation, due to the energetic electrons generated in the ablation preplasma. When the ablation pulse matches main pulse, the enhancement gets optimized because the electrons' energy density is highest. A scaling law between the ablation pulse and main pulse is confirmed by the simulation, showing that for given CPA pulse and target, proton energy improvement can be achieved several times by adjusting the target ablation.

Biophysics and clinical utility of irrigated-tip radiofrequency catheter ablation.

PubMed

Houmsse, Mahmoud; Daoud, Emile G

2012-01-01

Catheter ablation by radiofrequency (RF) energy has successfully eliminated cardiac tachyarrhythmias. RF ablation lesions are created by thermal energy. Electrode catheters with 4-mm-tips have been adequate to ablate arrhythmias located near the endocardium; however, the 4-mm-tip electrode does not readily ablate deeper tachyarrhythmia substrate. With 8- and 10-mm-tip RF electrodes, ablation lesions were larger; yet, these catheters are associated with increased risk for coagulum, char and thrombus formation, as well as myocardial steam rupture. Cooled-tip catheter technology was designed to cool the electrode tip, prevent excessive temperatures at the electrode tip-tissue interface, and thus allow continued delivery of RF current into the surrounding tissue. This ablation system creates larger and deeper ablation lesions and minimizes steam pops and thrombus formation. The purpose of this article is to review cooled-tip RF ablation biophysics and outcomes of clinical studies as well as to discuss future technological improvements.

Effect analysis of material properties of picosecond laser ablation for ABS/PVC

NASA Astrophysics Data System (ADS)

Tsai, Y. H.; Ho, C. Y.; Chiou, Y. J.

2017-06-01

This paper analytically investigates the picosecond laser ablation of ABS/PVC. Laser-pulsed ablation is a wellestablished tool for polymer. However the ablation mechanism of laser processing for polymer has not been thoroughly understood yet. This study utilized a thermal transport model to analyze the relationship between the ablation rate and laser fluences. This model considered the energy balance at the decomposition interface and Arrhenius law as the ablation mechanisms. The calculated variation of the ablation rate with the logarithm of the laser fluence agrees with the measured data. It is also validated in this work that the variation of the ablation rate with the logarithm of the laser fluence obeys Beer's law for low laser fluences. The effects of material properties and processing parameters on the ablation depth per pulse are also discussed for picosecond laser processing of ABS/PVC.

Femtosecond laser ablation of dentin and enamel: relationship between laser fluence and ablation efficiency.

PubMed

Chen, Hu; Liu, Jing; Li, Hong; Ge, Wenqi; Sun, Yuchun; Wang, Yong; Lü, Peijun

2015-02-01

The objective was to study the relationship between laser fluence and ablation efficiency of a femtosecond laser with a Gaussian-shaped pulse used to ablate dentin and enamel for prosthodontic tooth preparation. A diode-pumped thin-disk femtosecond laser with wavelength of 1025 nm and pulse width of 400 fs was used for the ablation of dentin and enamel. The laser spot was guided in a line on the dentin and enamel surfaces to form a groove-shaped ablation zone under a series of laser pulse energies. The width and volume of the ablated line were measured under a three-dimensional confocal microscope to calculate the ablation efficiency. Ablation efficiency for dentin reached a maximum value of 0.020 mm3∕J when the laser fluence was set at 6.51 J∕cm2. For enamel, the maximum ablation efficiency was 0.009 mm3∕J at a fluence of 7.59 J∕cm2.Ablation efficiency of the femtosecond laser on dentin and enamel is closely related to the laser fluence and may reach a maximum when the laser fluence is set to an appropriate value. © 2015 Society of Photo-Optical Instrumentation Engineers (SPIE)

Enhanced Radiofrequency Ablation With Magnetically Directed Metallic Nanoparticles.

PubMed

Nguyen, Duy T; Tzou, Wendy S; Zheng, Lijun; Barham, Waseem; Schuller, Joseph L; Shillinglaw, Benjamin; Quaife, Robert A; Sauer, William H

2016-05-01

Remote heating of metal located near a radiofrequency ablation source has been previously demonstrated. Therefore, ablation of cardiac tissue treated with metallic nanoparticles may improve local radiofrequency heating and lead to larger ablation lesions. We sought to evaluate the effect of magnetic nanoparticles on tissue sensitivity to radiofrequency energy. Ablation was performed using an ablation catheter positioned with 10 g of force over prepared ex vivo specimens. Tissue temperatures were measured and lesion volumes were acquired. An in vivo porcine thigh model was used to study systemically delivered magnetically guided iron oxide (FeO) nanoparticles during radiofrequency application. Magnetic resonance imaging and histological staining of ablated tissue were subsequently performed as a part of ablation lesion analysis. Ablation of ex vivo myocardial tissue treated with metallic nanoparticles resulted in significantly larger lesions with greater impedance changes and evidence of increased thermal conductivity within the tissue. Magnet-guided localization of FeO nanoparticles within porcine thigh preps was demonstrated by magnetic resonance imaging and iron staining. Irrigated ablation in the regions with greater FeO, after FeO infusion and magnetic guidance, created larger lesions without a greater incidence of steam pops. Metal nanoparticle infiltration resulted in significantly larger ablation lesions with altered electric and thermal conductivity. In vivo magnetic guidance of FeO nanoparticles allowed for facilitated radiofrequency ablation without direct infiltration into the targeted tissue. Further research is needed to assess the clinical applicability of this ablation strategy using metallic nanoparticles for the treatment of cardiac arrhythmias. © 2016 American Heart Association, Inc.

Five seconds of 50-60 W radio frequency atrial ablations were transmural and safe: an in vitro mechanistic assessment and force-controlled in vivo validation.

PubMed

Bhaskaran, Abhishek; Chik, William; Pouliopoulos, Jim; Nalliah, Chrishan; Qian, Pierre; Barry, Tony; Nadri, Fazlur; Samanta, Rahul; Tran, Ying; Thomas, Stuart; Kovoor, Pramesh; Thiagalingam, Aravinda

2017-05-01

Longer procedural time is associated with complications in radiofrequency atrial fibrillation ablation. We sought to reduce ablation time and thereby potentially reduce complications. The aim was to compare the dimensions and complications of 40 W/30 s setting to that of high-power ablations (50-80 W) for 5 s in the in vitro and in vivo models. In vitro ablations-40 W/30 s were compared with 40-80 W powers for 5 s. In vivo ablations-40 W/30 s were compared with 50-80 W powers for 5 s. All in vivo ablations were performed with 10 g contact force and 30 mL/min irrigation rate. Steam pops and depth of lung lesions identified post-mortem were noted as complications. A total of 72 lesions on the non-trabeculated part of right atrium were performed in 10 Ovine. All in vitro ablations except for the 40 W/5 s setting achieved the critical lesion depth of 2 mm. For in vivo ablations, all lesions were transmural, and the lesion depths for the settings of 40 W/30 s, 50 W/5 s, 60 W/5 s, 70 W/5 s, and 80 W/5 s were 2.2 ± 0.5, 2.3 ± 0.5, 2.1 ± 0.4, 2.0 ± 0.3, and 2.3 ± 0.7 mm, respectively. The lesion depths of short-duration ablations were similar to that of the conventional ablation. Steam pops occurred in the ablation settings of 40 W/30 s and 80 W/5 s in 8 and 11% of ablations, respectively. Complications were absent in short-duration ablations of 50 and 60 W. High-power, short-duration atrial ablation was as safe and effective as the conventional ablation. Compared with the conventional 40 W/30 s setting, 50 and 60 W ablation for 5 s achieved transmurality and had fewer complications. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.

Optimizing multimodality treatment for head and neck cancer in rural India.

PubMed

Trivedi, N P; Trivedi, P; Trivedi, H; Trivedi, S; Trivedi, N

2012-01-01

Multimodality treatment of head and neck cancer in rural India is not always feasible due to lack of infrastructure and logistics. To demonstrate the feasibility of multimodality treatment for head and neck cancer in a community setting in rural India. Community cancer center, retrospective review. This article focuses on practice environment in a cancer clinic in rural India. We evaluated patient profile, treatment protocols, infrastructure availability, factors impacting treatment decisions, cost estimations, completion of treatment, and major treatment-related complications for the patient population treated in our clinic for a 2-year period. A total of 230 head and neck cancer patients were treated with curative intent. Infrastructure support included basic operating room facility (cautery machine, suction, drill system, microscope, and anesthesia machine without ventilator support), blood bank, histopathology laboratory, and computerized tomography machine. Radiation therapy (RT) facility was available in a nearby city, about 75 km away. One hundred and fifty-four (67%) patients presented at an advanced stage, with 138 (60%) receiving multimodality treatment. One hundred and eighty-four (80%) patients underwent primary surgery and 167 (73%) received radiotherapy. Two hundred and twelve (92%) patients completed the treatment, 60 (26%) were lost to follow-up at 18-month median follow-up (range 12-26 months), with 112 patients (66%) being alive, disease free. Totally 142 were major head neck surgeries with 25 free flap reconstructions and 41 regional flaps. There were 15 (6%) major post-op complications and two perioperative mortalities. Average cost of treatment for single modality treatment was approximately 40,000 INR and for multimodality treatment was 80,000 INR. This study demonstrates that it is feasible to provide basic multimodality treatment to head and neck cancer patients in the community.

Connecting the Bird's Head to the Bird's Body - Cenozoic arc magmatism extends along the length of New Guinea.

NASA Astrophysics Data System (ADS)

Webb, Max; White, Lloyd; Jost, Benjamin

2017-04-01

New Guinea has a long, complicated history of arc magmatism. The present day shape of the island (resembling that of a bird in flight) formed as a result of oblique convergence of the Pacific and Caroline/Philippine plates with the northward moving Australian plate. This convergence resulted in multiple collisions of island arcs with continental crust, representing a modern day analogue to ancient accretionary orogens. This complex geological history has formed four major tectonic belts; accreted Palaeogene island arcs, the New Guinea Mobile Belt, the New Guinea Fold Belt and a stable platform. These tectonic belts are drawn across most of New Guinea in major review papers. However, these tectonic belts are not generally considered to extend through to New Guinea's western most peninsula (the Bird's Head). We present new field evidence, together with new U-Pb zircon geochronology and geochemical analyses from rocks collected within the Bird's Head. These document Middle to Late Miocene intermediate to felsic volcanic rocks and associated granitoid intrusives that formed along an active continental margin. These are effectively the equivalent of the Maramuni arc and Freida River Complex in eastern New Guinea. Several, broadly Eocene island arcs composed of dominantly mafic volcanic rocks are also found in the Bird's Head. These island arcs accreted along the Bird's Head sometime after their initial formation, possibly coinciding with Middle to Late Miocene active continental margin magmatism and we consider them to be equivalents of the Cyclops Mountains arc in Central New Guinea. This work demonstrates that New Guinea's east-west terranes are more extensive than previously thought. This potentially has implications for locating future ore deposits and understanding the relative position of the Bird's Head with respect to the rest of New Guinea in major plate reconstructions.

Optimal Perioperative Care in Major Head and Neck Cancer Surgery With Free Flap Reconstruction: A Consensus Review and Recommendations From the Enhanced Recovery After Surgery Society.

PubMed

Dort, Joseph C; Farwell, D Gregory; Findlay, Merran; Huber, Gerhard F; Kerr, Paul; Shea-Budgell, Melissa A; Simon, Christian; Uppington, Jeffrey; Zygun, David; Ljungqvist, Olle; Harris, Jeffrey

2017-03-01

Head and neck cancers often require complex, labor-intensive surgeries, especially when free flap reconstruction is required. Enhanced recovery is important in this patient population but evidence-based protocols on perioperative care for this population are lacking. To provide a consensus-based protocol for optimal perioperative care of patients undergoing head and neck cancer surgery with free flap reconstruction. Following endorsement by the Enhanced Recovery After Surgery (ERAS) Society to develop this protocol, a systematic review was conducted for each topic. The PubMed and Cochrane databases were initially searched to identify relevant publications on head and neck cancer surgery from 1965 through April 2015. Consistent key words for each topic included "head and neck surgery," "pharyngectomy," "laryngectomy," "laryngopharyngectomy," "neck dissection," "parotid lymphadenectomy," "thyroidectomy," "oral cavity resection," "glossectomy," and "head and neck." The final selection of literature included meta-analyses and systematic reviews as well as randomized controlled trials where available. In the absence of high-level data, case series and nonrandomized studies in head and neck cancer surgery patients or randomized controlled trials and systematic reviews in non-head and neck cancer surgery patients, were considered. An international panel of experts in major head and neck cancer surgery and enhanced recovery after surgery reviewed and assessed the literature for quality and developed recommendations for each topic based on the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system. All recommendations were graded following a consensus discussion among the expert panel. The literature search, including a hand search of reference lists, identified 215 relevant publications that were considered to be the best evidence for the topic areas. A total of 17 topic areas were identified for inclusion in the protocol for the perioperative care of patients undergoing major head and neck cancer surgery with free flap reconstruction. Best practice includes several elements of perioperative care. Among these elements are the provision of preoperative carbohydrate treatment, pharmacologic thromboprophylaxis, perioperative antibiotics in clean-contaminated procedures, corticosteroid and antiemetic medications, short acting anxiolytics, goal-directed fluid management, opioid-sparing multimodal analgesia, frequent flap monitoring, early mobilization, and the avoidance of preoperative fasting. The evidence base for specific perioperative care elements in head and neck cancer surgery is variable and in many cases information from different surgerical procedures form the basis for these recommendations. Clinical evaluation of these recommendations is a logical next step and further research in this patient population is warranted.

Ablation of Mrds1/Ofcc1 Induces Hyper-γ-Glutamyl Transpeptidasemia without Abnormal Head Development and Schizophrenia-Relevant Behaviors in Mice

PubMed Central

Ohnishi, Tetsuo; Yamada, Kazuo; Watanabe, Akiko; Ohba, Hisako; Sakaguchi, Toru; Honma, Yota; Iwayama, Yoshimi; Toyota, Tomoko; Maekawa, Motoko; Watanabe, Kazutada; Detera-Wadleigh, Sevilla D.; Wakana, Shigeharu; Yoshikawa, Takeo

2011-01-01

Mutations in the Opo gene result in eye malformation in medaka fish. The human ortholog of this gene, MRDS1/OFCC1, is a potentially causal gene for orofacial cleft, as well as a susceptibility gene for schizophrenia, a devastating mental illness. Based on this evidence, we hypothesized that this gene could perform crucial functions in the development of head and brain structures in vertebrates. To test this hypothesis, we created Mrds1/Ofcc1-null mice. Mice were examined thoroughly using an abnormality screening system referred to as “the Japan Mouse Clinic”. No malformations of the head structure, eye or other parts of the body were apparent in these knockout mice. However, the mutant mice showed a marked increase in serum γ-glutamyl transpeptidase (GGT), a marker for liver damage, but no abnormalities in other liver-related measurements. We also performed a family-based association study on the gene in schizophrenia samples of Japanese origin. We found five single nucleotide polymorphisms (SNPs) located across the gene that showed significant transmission distortion, supporting a prior report of association in a Caucasian cohort. However, the knockout mice showed no behavioral phenotypes relevant to schizophrenia. In conclusion, disruption of the Mrds1/Ofcc1 gene elicits asymptomatic hyper-γ-glutamyl-transpeptidasemia in mice. However, there were no phenotypes to support a role for the gene in the development of eye and craniofacial structures in vertebrates. These results prompt further examination of the gene, including its putative contribution to hyper-γ-glutamyl transpeptidasemia and schizophrenia. PMID:22242126

Physical properties of meteoroids based on middle and upper atmosphere radar measurements

NASA Astrophysics Data System (ADS)

Gritsevich, M.; Kero, J.; Virtanen, J.; Szasz, C.; Nakamura, T.; Peltoniemi, J.; Koschny, D.

2014-07-01

We present a novel approach to reliably interpret the meteor head-echo scattering measurements detected by the 46.5 MHz MU radar system near Shigaraki, Japan. A meteor head echo is caused by radio waves scattered from the dense region of plasma surrounding and co-moving with a meteoroid during atmospheric flight. The signal Doppler shift and/or range rate of the target can therefore be used to determine meteoroid velocity. The data reduction steps include determining the exact trajectory of the meteoroids entering the observation volume of the antenna beam and calculating meteoroid mass and velocity as a function of time. The model is built using physically-based parametrization. The considered observation volume is narrow, elongated in the vertical direction, and its area of greatest sensitivity covers a circular area of about 10 km diameter at an altitude of 100 km above the radar. Over 100,000 meteor head echoes have been detected over past years of observations. Most of the events are faint with no alternative to be detected visually or with intensified video (ICCD) cameras. In this study we are focusing on objects which have entered the atmosphere with almost vertical trajectories, to ensure the observed segment of the trajectory to be as complete as possible, without loss of its beginning or end part due to beam-pattern-related loss of signal power. The analysis output parameters are range, altitude, radial velocity, meteoroid velocity, instantaneous target position, Radar Cross Section (RCS), meteor radiant, meteoroid ballistic and ablation coefficients, mass loss parameter and meteoroid mass, with possibility to derive other parameters.

High-performance intraoperative cone-beam CT on a mobile C-arm: an integrated system for guidance of head and neck surgery

NASA Astrophysics Data System (ADS)

Siewerdsen, J. H.; Daly, M. J.; Chan, H.; Nithiananthan, S.; Hamming, N.; Brock, K. K.; Irish, J. C.

2009-02-01

A system for intraoperative cone-beam CT (CBCT) surgical guidance is under development and translation to trials in head and neck surgery. The system provides 3D image updates on demand with sub-millimeter spatial resolution and soft-tissue visibility at low radiation dose, thus overcoming conventional limitations associated with preoperative imaging alone. A prototype mobile C-arm provides the imaging platform, which has been integrated with several novel subsystems for streamlined implementation in the OR, including: real-time tracking of surgical instruments and endoscopy (with automatic registration of image and world reference frames); fast 3D deformable image registration (a newly developed multi-scale Demons algorithm); 3D planning and definition of target and normal structures; and registration / visualization of intraoperative CBCT with the surgical plan, preoperative images, and endoscopic video. Quantitative evaluation of surgical performance demonstrates a significant advantage in achieving complete tumor excision in challenging sinus and skull base ablation tasks. The ability to visualize the surgical plan in the context of intraoperative image data delineating residual tumor and neighboring critical structures presents a significant advantage to surgical performance and evaluation of the surgical product. The system has been translated to a prospective trial involving 12 patients undergoing head and neck surgery - the first implementation of the research prototype in the clinical setting. The trial demonstrates the value of high-performance intraoperative 3D imaging and provides a valuable basis for human factors analysis and workflow studies that will greatly augment streamlined implementation of such systems in complex OR environments.

Physical Properties of Meteoroids based on Middle and Upper Atmosphere Radar Measurements

NASA Astrophysics Data System (ADS)

Gritsevich, Maria; Nakamura, Takuji; Kero, Johan; Szasz, Csilla; Virtanen, Jenni; Peltoniemi, Jouni; Koschny, Detlef

We present a novel approach to reliably interpret the meteor head echo scattering measurements detected by the 46.5 MHz MU radar system near Shigaraki, Japan. A meteor head echo is caused by radio waves scattered from the dense region of plasma surrounding and co-moving with a meteoroid during atmospheric flight. The signal Doppler shift and/or range rate of the target can therefore be used to determine meteoroid velocity. The data reduction steps include determining the exact trajectory of the meteoroids entering the observation volume of the antenna beam and calculating meteoroid mass and velocity as a function of time. The model is built using physically based parameterization. The considered observation volume is narrow, elongated in the vertical direction, and its area of greatest sensitivity covers a circular area of about 10 km diameter at an altitude of 100 km above the radar. Over 100000 meteor head echoes have been detected over past years of observations. Most of the events are faint with no alternative to be detected visually or with intensified video (ICCD) cameras. In this study we are focusing on objects which have entered the atmosphere with almost vertical trajectories, to ensure the observed segment of the trajectory to be as complete as possible, without loss of its beginning or end part due to beam-pattern related loss of signal power. The analysis output parameters are range, altitude, radial velocity, meteoroid velocity, instantaneous target position, Radar Cross Section (RCS), meteor radiant, meteoroid ballistic and ablation coefficients, mass loss parameter and meteoroid mass, with possibility to derive other parameters.

Analysis of the change in peak corneal temperature during excimer laser ablation in porcine eyes

NASA Astrophysics Data System (ADS)

Mosquera, Samuel Arba; Verma, Shwetabh

2015-07-01

The objective is to characterize the impact of different ablation parameters on the thermal load during corneal refractive surgery by means of excimer laser ablation on porcine eyes. One hundred eleven ablations were performed in 105 porcine eyes. Each ablation was recorded using infrared thermography and analyzed mainly based on the two tested local frequencies (40 Hz, clinical local frequency; 1000 Hz, no local frequency). The change in peak corneal temperature was analyzed with respect to varying ablation parameters [local frequency, system repetition rate, pulse energy, optical zone (OZ) size, and refractive correction]. Transepithelial ablations were also compared to intrastromal ablations. The average of the baseline temperature across all eyes was 20.5°C±1.1 (17.7°C to 22.2°C). Average of the change in peak corneal temperature for all clinical local frequency ablations was 5.8°C±0.8 (p=3.3E-53 to baseline), whereas the average was 9.0°C±1.5 for all no local frequency ablations (p=1.8E-35 to baseline, 1.6E-16 to clinical local frequency ablations). A logarithmic relationship was observed between the changes in peak corneal temperature with increasing local frequency. For clinical local frequency, change in peak corneal temperature was comparatively flat (r2=0.68 with a range of 1.5°C) with increasing system repetition rate and increased linearly with increasing OZ size (r2=0.95 with a range of 2.4°C). Local frequency controls help maintain safe corneal temperature increase during excimer laser ablations. Transepithelial ablations induce higher thermal load compared to intrastromal ablations, indicating a need for stronger thermal controls in transepithelial refractive procedures.

The Femtosecond Laser Ablation on Ultrafine-Grained Copper

NASA Astrophysics Data System (ADS)

Lu, Jianxun; Wu, Xiaoyu; Ruan, Shuangchen; Guo, Dengji; Du, Chenlin; Liang, Xiong; Wu, Zhaozhi

2018-07-01

To investigate the effects of femtosecond laser ablation on the surface morphology and microstructure of ultrafine-grained copper, point, single-line scanning, and area scanning ablation of ultrafine-grained and coarse-grained copper were performed at room temperature. The ablation threshold gradually increased and materials processing became more difficult with decreasing grain size. In addition, the ablation depth and width of the channels formed by single-line scanning ablation gradually increased with increasing grain size for the same laser pulse energy. The microhardness of the ablated specimens was also evaluated as a function of laser pulse energy using area scanning ablation. The microhardness difference before and after ablation increased with decreasing grain size for the same laser pulse energy. In addition, the microhardness after ablation gradually decreased with increasing laser pulse energy for the ultrafine-grained specimens. However, for the coarse-grained copper specimens, no clear changes of the microhardness were observed after ablation with varying laser pulse energies. The grain sizes of the ultrafine-grained specimens were also surveyed as a function of laser pulse energy using electron backscattered diffraction (EBSD). The heat generated by laser ablation caused recrystallization and grain growth of the ultrafine-grained copper; moreover, the grain size gradually increased with increasing pulse energy. In contrast, no obvious changes in grain size were observed for the coarse-grained copper specimens with increasing pulse energy.

The Femtosecond Laser Ablation on Ultrafine-Grained Copper

NASA Astrophysics Data System (ADS)

Lu, Jianxun; Wu, Xiaoyu; Ruan, Shuangchen; Guo, Dengji; Du, Chenlin; Liang, Xiong; Wu, Zhaozhi

2018-05-01

To investigate the effects of femtosecond laser ablation on the surface morphology and microstructure of ultrafine-grained copper, point, single-line scanning, and area scanning ablation of ultrafine-grained and coarse-grained copper were performed at room temperature. The ablation threshold gradually increased and materials processing became more difficult with decreasing grain size. In addition, the ablation depth and width of the channels formed by single-line scanning ablation gradually increased with increasing grain size for the same laser pulse energy. The microhardness of the ablated specimens was also evaluated as a function of laser pulse energy using area scanning ablation. The microhardness difference before and after ablation increased with decreasing grain size for the same laser pulse energy. In addition, the microhardness after ablation gradually decreased with increasing laser pulse energy for the ultrafine-grained specimens. However, for the coarse-grained copper specimens, no clear changes of the microhardness were observed after ablation with varying laser pulse energies. The grain sizes of the ultrafine-grained specimens were also surveyed as a function of laser pulse energy using electron backscattered diffraction (EBSD). The heat generated by laser ablation caused recrystallization and grain growth of the ultrafine-grained copper; moreover, the grain size gradually increased with increasing pulse energy. In contrast, no obvious changes in grain size were observed for the coarse-grained copper specimens with increasing pulse energy.

Heat sink phenomenon of bipolar and monopolar radiofrequency ablation observed using polypropylene tubes for vessel simulation.

PubMed

Al-Alem, Ihssan; Pillai, Krishna; Akhter, Javed; Chua, Terence C; Morris, David L

2014-06-01

Radiofrequency ablation (RFA) is widely used for treating liver tumors; recurrence is common owing to proximity to blood vessels possibly due to the heat sink effect. We seek to investigate this phenomenon using unipolar and bipolar RFA on an egg white tumor tissue model and an animal liver model. Temperature profiles during ablation (with and without vessel simulation) were studied, using both bipolar and unipolar RFA probes by 4 strategically placed temperature leads to monitor temperature profile during ablation. The volume of ablated tissue was also measured. The volume ablated during vessel simulation confirmed the impact of the heat sink phenomenon. The heat sink effect of unipolar RFA was greater compared with bipolar RFA (ratio of volume affected 2:1) in both tissue and liver models. The volume ablated using unipolar RFA was less than the bipolar RFA (ratio of volume ablated = 1:4). Unipolar RFA achieved higher ablation temperatures (122°C vs 98°C). Unipolar RFA resulted in tissue damage beyond the vessel, which was not observed using bipolar RFA. Bipolar RFA ablates a larger tumor volume compared with unipolar RFA, with a single ablation. The impact of heat sink phenomenon in tumor ablation is less so with bipolar than unipolar RFA with sparing of adjacent vessel damage. © The Author(s) 2013.

Selective rear side ablation of thin nickel-chromium-alloy films using ultrashort laser pulses

NASA Astrophysics Data System (ADS)

Pabst, Linda; Ullmann, Frank; Ebert, Robby; Exner, Horst

2018-03-01

In recent years, the selective laser structuring from the transparent substrate side plays an increased role in thin film processing. The rear side ablation is a highly effective ablation method for thin film structuring and revels a high structuring quality. Therefore, the rear side ablation of nickel-chromium-alloy thin films on glass substrate was investigated using femtosecond laser irradiation. Single and multiple pulses ablation thresholds as well as the incubation coefficient were determined. By irradiation from the transparent substrate side at low fluences a cracking or a partly delamination of the film could be observed. By increasing the fluence the most part of the film was ablated, however, a very thin film remained at the interface of the glass substrate. This thin remaining layer could be completely ablated by two pulses. A further increase of the pulse number had no influence on the ablation morphology. The ablated film was still intact and an entire disc or fragments could be collected near the ablation area. The fragments showed no morphology change and were still in solid state.

Engine having a variable valve actuation system

DOEpatents

Hefler, Gregory W [Chillicothe, IL

2004-10-12

An engine has a cylinder head having a first surface and a second surface spaced from the first surface. A valve is moveably connected to the cylinder head. A rocker arm is connected to the valve, and a rocker shaft having a first location spaced a maximum distance from the cylinder head is connected to the rocker arm. A support member has and an actuator fluid passage network. The actuator fluid passage network defines a volume. The support member is connected to the cylinder head and is positioned such that a majority of the volume of the actuator fluid passage network is between the first location of the rocker shaft and the second surface of the cylinder head.

Engine having a variable valve actuation system

DOEpatents

Hefler, Gregory W.

2005-10-12

An engine has a cylinder head having a first surface and a second surface spaced from the first surface. A valve is moveably connected to the cylinder head. A rocker arm is connected to the valve, and a rocker shaft having a first location spaced a maximum distance from the cylinder head is connected to the rocker arm. A support member has and an actuator fluid passage network. The actuator fluid passage network defines a volume. The support member is connected to the cylinder head and is positioned such that a majority of the volume of the actuator fluid passage network is between the first location of the rocker shaft and the second surface of the cylinder head.

Identification and quantification of caffeoylquinic acids and flavonoids from artichoke (Cynara scolymus L.) heads, juice, and pomace by HPLC-DAD-ESI/MS(n).

PubMed

Schütz, Katrin; Kammerer, Dietmar; Carle, Reinhold; Schieber, Andreas

2004-06-30

A method for the identification and quantification of phenolic compounds from artichoke (Cynara scolymus L.) heads, juice, and pomace by HPLC with diode array and mass spectrometric detection was developed. Among the 22 major compounds, 11 caffeoylquinic acids and 8 flavonoids were detected. Quantification of individual compounds was carried out by external calibration. Apigenin 7-O-glucuronide was found to be the major flavonoid in all samples investigated. 1,5-Di-O-caffeoylquinic acid represented the major hydroxycinnamic acid, with 3890 mg/kg in artichoke heads and 3269 mg/kg in the pomace, whereas in the juice 1,3-di-O-caffeoylquinic acid (cynarin) was predominant, due to the isomerization during processing. Total phenolic contents of approximately 12 g/kg on a dry matter basis revealed that artichoke pomace is a promising source of phenolic compounds that might be recovered and used as natural antioxidants or functional food ingredients.

Comparing Immunohistologic and Demographic Variables of Head and Neck Squamous Cell Carcinoma

DTIC Science & Technology

2015-06-01

HPV 16 and 18 which have a well-established association with cervical cancers . However, HPV 16 accounts for the majority ofHPV...These cancers are now subdivided into HPV associated ( HPV - SCC) and non- HPV associated squamous cell (SCC) carcinomas. HPV -SCG is a distinct entity... cell carcinomas. Laryngoscope 2009; 119(8): 1542-1549. 13. Venuti A, Paolini F. HPV detection methods in head and neck cancer . Head Neck

Multilevel groundwater monitoring of hydraulic head and temperature in the eastern Snake River Plain aquifer, Idaho National Laboratory, Idaho, 2009–10

USGS Publications Warehouse

Twining, Brian V.; Fisher, Jason C.

2012-01-01

During 2009 and 2010, the U.S. Geological Survey’s Idaho National Laboratory Project Office, in cooperation with the U.S. Department of Energy, collected quarterly, depth-discrete measurements of fluid pressure and temperature in nine boreholes located in the eastern Snake River Plain aquifer. Each borehole was instrumented with a multilevel monitoring system consisting of a series of valved measurement ports, packer bladders, casing segments, and couplers. Multilevel monitoring at the Idaho National Laboratory has been ongoing since 2006. This report summarizes data collected from three multilevel monitoring wells installed during 2009 and 2010 and presents updates to six multilevel monitoring wells. Hydraulic heads (heads) and groundwater temperatures were monitored from 9 multilevel monitoring wells, including 120 hydraulically isolated depth intervals from 448.0 to 1,377.6 feet below land surface. Quarterly head and temperature profiles reveal unique patterns for vertical examination of the aquifer’s complex basalt and sediment stratigraphy, proximity to aquifer recharge and discharge, and groundwater flow. These features contribute to some of the localized variability even though the general profile shape remained consistent over the period of record. Major inflections in the head profiles almost always coincided with low-permeability sediment layers and occasionally thick sequences of dense basalt. However, the presence of a sediment layer or dense basalt layer was insufficient for identifying the location of a major head change within a borehole without knowing the true areal extent and relative transmissivity of the lithologic unit. Temperature profiles for boreholes completed within the Big Lost Trough indicate linear conductive trends; whereas, temperature profiles for boreholes completed within the axial volcanic high indicate mostly convective heat transfer resulting from the vertical movement of groundwater. Additionally, temperature profiles provide evidence for stratification and mixing of water types along the southern boundary of the Idaho National Laboratory. Vertical head and temperature change were quantified for each of the nine multilevel monitoring systems. The vertical head gradients were defined for the major inflections in the head profiles and were as high as 2.1 feet per foot. Low vertical head gradients indicated potential vertical connectivity and flow, and large gradient inflections indicated zones of relatively low vertical connectivity. Generally, zones that primarily are composed of fractured basalt displayed relatively small vertical head differences. Large head differences were attributed to poor vertical connectivity between fracture units because of sediment layering and/or dense basalt. Groundwater temperatures in all boreholes ranged from 10.2 to 16.3˚C. Normalized mean hydraulic head values were analyzed for all nine multilevel monitoring wells for the period of record (2007-10). The mean head values suggest a moderately positive correlation among all boreholes, which reflects regional fluctuations in water levels in response to seasonality. However, the temporal trend is slightly different when the location is considered; wells located along the southern boundary, within the axial volcanic high, show a strongly positive correlation.

Magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) ablation of liver tumours.

PubMed

Wijlemans, J W; Bartels, L W; Deckers, R; Ries, M; Mali, W P Th M; Moonen, C T W; van den Bosch, M A A J

2012-09-28

Recent decades have seen a paradigm shift in the treatment of liver tumours from invasive surgical procedures to minimally invasive image-guided ablation techniques. Magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) is a novel, completely non-invasive ablation technique that has the potential to change the field of liver tumour ablation. The image guidance, using MR imaging and MR temperature mapping, provides excellent planning images and real-time temperature information during the ablation procedure. However, before clinical implementation of MR-HIFU for liver tumour ablation is feasible, several organ-specific challenges have to be addressed. In this review we discuss the MR-HIFU ablation technique, the liver-specific challenges for MR-HIFU tumour ablation, and the proposed solutions for clinical translation.

Magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) ablation of liver tumours

PubMed Central

Bartels, L.W.; Deckers, R.; Ries, M.; Mali, W.P.Th.M.; Moonen, C.T.W.; van den Bosch, M.A.A.J.

2012-01-01

Abstract Recent decades have seen a paradigm shift in the treatment of liver tumours from invasive surgical procedures to minimally invasive image-guided ablation techniques. Magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) is a novel, completely non-invasive ablation technique that has the potential to change the field of liver tumour ablation. The image guidance, using MR imaging and MR temperature mapping, provides excellent planning images and real-time temperature information during the ablation procedure. However, before clinical implementation of MR-HIFU for liver tumour ablation is feasible, several organ-specific challenges have to be addressed. In this review we discuss the MR-HIFU ablation technique, the liver-specific challenges for MR-HIFU tumour ablation, and the proposed solutions for clinical translation. PMID:23022541

A study of angular dependence in the ablation rate of polymers by nanosecond pulses

NASA Astrophysics Data System (ADS)

Pedder, James E. A.; Holmes, Andrew S.

2006-02-01

Measurements of ablation rate have traditionally been carried out only at normal incidence. However, in real-world applications ablation is often carried out at oblique angles, and it is useful to have prior knowledge of the ablation rate in this case. Detailed information about the angular dependence is also important for the development of ablation simulation tools, and can provide additional insight into the ablation mechanism. Previously we have reported on the angular dependence of direct-write ablation at 266 nm wavelength in solgel and polymer materials. In this paper we present a systematic study of angular dependence for excimer laser ablation of two polymer materials of interest for microfabrication: polycarbonate and SU8 photoresist. The results are used to improve simulation models to aid in mask design.

Efficacy and survival analysis of percutaneous radiofrequency versus microwave ablation for hepatocellular carcinoma: an Egyptian multidisciplinary clinic experience.

PubMed

Abdelaziz, Ashraf; Elbaz, Tamer; Shousha, Hend Ibrahim; Mahmoud, Sherif; Ibrahim, Mostafa; Abdelmaksoud, Ahmed; Nabeel, Mohamed

2014-12-01

Hepatocellular carcinoma (HCC) is a primary tumor of the liver with poor prognosis. For early stage HCC, treatment options include surgical resection, liver transplantation, and percutaneous ablation. Percutaneous ablative techniques (radiofrequency and microwave techniques) emerged as best therapeutic options for nonsurgical patients. We aimed to determine the safety and efficacy of radiofrequency and microwave procedures for ablation of early stage HCC lesions and prospectively follow up our patients for survival analysis. One Hundred and 11 patients with early HCC are managed in our multidisciplinary clinic using either radiofrequency or microwave ablation. Patients are assessed for efficacy and safety. Complete ablation rate, local recurrence, and overall survival analysis are compared between both procedures. Radiofrequency ablation group (n = 45) and microwave ablation group (n = 66) were nearly comparable as regards the tumor and patients characteristics. Complete ablation was achieved in 94.2 and 96.1% of patients managed by radiofrequency and microwave ablation techniques, respectively (p value 0.6) with a low rate of minor complications (11.1 and 3.2, respectively) including subcapsular hematoma, thigh burn, abdominal wall skin burn, and pleural effusion. Ablation rates did not differ between ablated lesions ≤ 3 and 3-5 cm. A lower incidence of local recurrence was observed in microwave group (3.9 vs. 13.5% in radiofrequency group, p value 0.04). No difference between both groups as regards de novo lesions, portal vein thrombosis, and abdominal lymphadenopathy. The overall actuarial probability of survival was 91.6% at 1 year and 86.1% at 2 years with a higher survival rates noticed in microwave group but still without significant difference (p value 0.49). Radiofrequency and microwave ablations led to safe and equivalent ablation and survival rates (with superiority for microwave ablation as regards the incidence of local recurrence).

Pleural Puncture that Excludes the Ablation Zone Decreases the Risk of Pneumothorax after Percutaneous Microwave Ablation in Porcine Lung

PubMed Central

Lee, Kyungmouk Steve; Takaki, Haruyuki; Yarmohammadi, Hooman; Srimathveeravalli, Govindarajan; Luchins, Kerith; Monette, Sébastien; Nair, Sreejit; Kishore, Sirish; Erinjeri, Joseph P.

2017-01-01

Purpose To test the hypothesis that the geometry of probe placement with respect to the pleural puncture site affects the risk of pneumothorax after microwave (MW) ablation in the lung. Materials and Methods Computed tomography–guided MW ablation of the lung was performed in 8 swine under general anesthesia and mechanical ventilation. The orientation of the 17-gauge probe was either perpendicular (90°) or parallel (< 30°) with respect to the pleural puncture site, and the ablation power was 30 W or 65 W for 5 minutes. After MW ablation, swine were euthanized, and histopathologic changes were assessed. Frequency and factors affecting pneumothorax were evaluated by multivariate analysis. Results Among 62 lung MW ablations, 13 (21%) pneumothoraces occurred. No statistically significant difference was noted in the rate of pneumothorax between the perpendicular and the parallel orientations of the probe (31% vs 14%; odds ratio [OR], 2.8; P = .11). The pneumothorax rate was equal for 65-W and 30-W ablation powers (21% and 21%; OR, 1.0; P = .94). Under multivariate analysis, 2 factors were independent positive predictors of pneumothorax: ablation zone inclusive of pleural insertion point (OR, 7.7; P = .02) and time since intubation (hours) (OR, 2.7; P = .02). Conclusions Geometries where the pleural puncture site excluded the ablation zone decreased pneumothorax in swine undergoing MW ablation in the lung. Treatment planning to ensure that the pleural puncture site excludes the subsequent ablation zone may reduce the rate of pneumothorax in patients undergoing MW ablation in the lung. PMID:25753501

Visualizing ex vivo radiofrequency and microwave ablation zones using electrode vibration elastography

PubMed Central

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

2012-01-01

Purpose: Electrode vibration elastography is a new shear wave imaging technique that can be used to visualize thermal ablation zones. Prior work has shown the ability of electrode vibration elastography to delineate radiofrequency ablations; however, there has been no previous study of delineation of microwave ablations or radiological–pathological correlations using multiple observers. Methods: Radiofrequency and microwave ablations were formed in ex vivo bovine liver tissue. Their visualization was compared on shear wave velocity and maximum displacement images. Ablation dimensions were compared to gross pathology. Elastographic imaging and gross pathology overlap and interobserver variability were quantified using similarity measures. Results: Elastographic imaging correlated with gross pathology. Correlation of area estimates was better in radiofrequency than in microwave ablations, with Pearson coefficients of 0.79 and 0.54 on shear wave velocity images and 0.90 and 0.70 on maximum displacement images for radiofrequency and microwave ablations, respectively. The absolute relative difference in area between elastographic imaging and gross pathology was 18.9% and 22.9% on shear wave velocity images and 16.0% and 23.1% on maximum displacement images for radiofrequency and microwave ablations, respectively. Conclusions: Statistically significant radiological–pathological correlation was observed in this study, but correlation coefficients were lower than other modulus imaging techniques, most notably in microwave ablations. Observers provided similar delineations for most thermal ablations. These results suggest that electrode vibration elastography is capable of imaging thermal ablations, but refinement of the technique may be necessary before it can be used to monitor thermal ablation procedures clinically. PMID:23127063

Beside the point: Mothers' head nodding and shaking gestures during parent-child play.

PubMed

Fusaro, Maria; Vallotton, Claire D; Harris, Paul L

2014-05-01

Understanding the context for children's social learning and language acquisition requires consideration of caregivers' multi-modal (speech, gesture) messages. Though young children can interpret both manual and head gestures, little research has examined the communicative input that children receive via parents' head gestures. We longitudinally examined the frequency and communicative functions of mothers' head nodding and head shaking gestures during laboratory play sessions for 32 mother-child dyads, when the children were 14, 20, and 30 months of age. The majority of mothers produced head nods more frequently than head shakes. Both gestures contributed to mothers' verbal attempts at behavior regulation and dialog. Mothers' head nods primarily conveyed agreement with, and attentiveness to, children's utterances, and accompanied affirmative statements and yes/no questions. Mothers' head shakes primarily conveyed prohibitions and statements with negations. Changes over time appeared to reflect corresponding developmental changes in social and communicative dimensions of caregiver-child interaction. Directions for future research are discussed regarding the role of head gesture input in socialization and in supporting language development. Copyright © 2014 Elsevier Inc. All rights reserved.

Genetic disruption of SOD1 gene causes glucose intolerance and impairs β-cell function.

PubMed

Muscogiuri, Giovanna; Salmon, Adam B; Aguayo-Mazzucato, Cristina; Li, Mengyao; Balas, Bogdan; Guardado-Mendoza, Rodolfo; Giaccari, Andrea; Reddick, Robert L; Reyna, Sara M; Weir, Gordon; Defronzo, Ralph A; Van Remmen, Holly; Musi, Nicolas

2013-12-01

Oxidative stress has been associated with insulin resistance and type 2 diabetes. However, it is not clear whether oxidative damage is a cause or a consequence of the metabolic abnormalities present in diabetic subjects. The goal of this study was to determine whether inducing oxidative damage through genetic ablation of superoxide dismutase 1 (SOD1) leads to abnormalities in glucose homeostasis. We studied SOD1-null mice and wild-type (WT) littermates. Glucose tolerance was evaluated with intraperitoneal glucose tolerance tests. Peripheral and hepatic insulin sensitivity was quantitated with the euglycemic-hyperinsulinemic clamp. β-Cell function was determined with the hyperglycemic clamp and morphometric analysis of pancreatic islets. Genetic ablation of SOD1 caused glucose intolerance, which was associated with reduced in vivo β-cell insulin secretion and decreased β-cell volume. Peripheral and hepatic insulin sensitivity were not significantly altered in SOD1-null mice. High-fat diet caused glucose intolerance in WT mice but did not further worsen the glucose intolerance observed in standard chow-fed SOD1-null mice. Our findings suggest that oxidative stress per se does not play a major role in the pathogenesis of insulin resistance and demonstrate that oxidative stress caused by SOD1 ablation leads to glucose intolerance secondary to β-cell dysfunction.

Genetic Disruption of SOD1 Gene Causes Glucose Intolerance and Impairs β-Cell Function

PubMed Central

Muscogiuri, Giovanna; Salmon, Adam B.; Aguayo-Mazzucato, Cristina; Li, Mengyao; Balas, Bogdan; Guardado-Mendoza, Rodolfo; Giaccari, Andrea; Reddick, Robert L.; Reyna, Sara M.; Weir, Gordon; DeFronzo, Ralph A.; Van Remmen, Holly; Musi, Nicolas

2013-01-01

Oxidative stress has been associated with insulin resistance and type 2 diabetes. However, it is not clear whether oxidative damage is a cause or a consequence of the metabolic abnormalities present in diabetic subjects. The goal of this study was to determine whether inducing oxidative damage through genetic ablation of superoxide dismutase 1 (SOD1) leads to abnormalities in glucose homeostasis. We studied SOD1-null mice and wild-type (WT) littermates. Glucose tolerance was evaluated with intraperitoneal glucose tolerance tests. Peripheral and hepatic insulin sensitivity was quantitated with the euglycemic-hyperinsulinemic clamp. β-Cell function was determined with the hyperglycemic clamp and morphometric analysis of pancreatic islets. Genetic ablation of SOD1 caused glucose intolerance, which was associated with reduced in vivo β-cell insulin secretion and decreased β-cell volume. Peripheral and hepatic insulin sensitivity were not significantly altered in SOD1-null mice. High-fat diet caused glucose intolerance in WT mice but did not further worsen the glucose intolerance observed in standard chow–fed SOD1-null mice. Our findings suggest that oxidative stress per se does not play a major role in the pathogenesis of insulin resistance and demonstrate that oxidative stress caused by SOD1 ablation leads to glucose intolerance secondary to β-cell dysfunction. PMID:24009256

Outcome of 1000 liver cancer patients evaluated at the UPMC Liver Cancer Center.

PubMed

Geller, David A; Tsung, Allan; Marsh, J Wallis; Dvorchik, Igor; Gamblin, T Clark; Carr, Brian I

2006-01-01

We evaluated 1000 consecutive patients with liver tumors at the University of Pittsburgh Medical Center (UPMC) Liver Cancer Center over the 4-year period from August 2000 to August 2004. Of the 1000 patients seen, 573 had primary liver cancer and 427 had metastatic cancer to the liver. The mean age of the patients evaluated was 62.2 years, and 61% were male. Treatment consisted of a liver surgical procedure (resection or radiofrequency ablation) in 369 cases (36.9%), hepatic intra-arterial regional therapy (transarterial chemoembolization or (90)yttrium microspheres) in 524 cases (52.4%), systemic chemotherapy in 35 cases (3.5%), and palliative care in 72 patients (7.2%). For treated patients, median survival was 884 days for those undergoing resection/radiofrequency ablation, compared to 295 days with regional therapy. These data indicate that over 90% of patients with liver cancer evaluated at a tertiary referral center can be offered some form of therapy. Survival rates are superior with a liver resection or ablation procedure, which is likely consistent with selection bias. Hepatocellular carcinoma was the most common tumor seen due to referral pattern and screening of hepatitis patients at a major liver transplant center. The most common reason for offering palliative care was hepatic insufficiency usually associated with cirrhosis.

Laser, radiofrequency, and ethanol ablation for the management of thyroid nodules.

PubMed

Papini, Enrico; Gugliemi, Rinaldo; Pacella, Claudio Maurizio

2016-10-01

The majority of benign thyroid nodules are nearly asymptomatic, remain stable in size, and do not require treatment. However, a minority of patients with growing nodules may complain of local symptoms or have cosmetic concerns, and thus seek surgical consultation. The timely use of ultrasound-guided minimally invasive procedures can change the natural history of benign enlarging thyroid nodules. The procedures produce persistent shrinkage of thyroid nodules and are associated with improvement of local symptoms. Among the various procedures, percutaneous ethanol injection represents the first-line treatment for relapsing thyroid cysts. In solid nonfunctioning nodules, laser and radiofrequency ablation produces a more than 50% reduction in nodular volume that remains persistent over several years. For hyperfunctioning nodules, thermal ablation techniques are not appropriate unless radioactive iodine is contraindicated or not accessible. MITs are best suited for the management of medium or large-sized nodules that are sonographically well visualized. Conversely, large nodules or nodular goiters that extend into the chest are difficult to treat. MITs are performed in outpatient clinics, are less expensive, and have a lower risk of complications, compared to surgery, and usually do not induce thyroid dysfunction. However, malignancy should be ruled out with a dedicated ultrasound neck assessment and repeat fine needle aspiration of the lesion before treatment.

The use of electrocautery as the primary ablation modality for malignant and benign airway obstruction.

PubMed

Wahidi, Momen M; Unroe, Mark A; Adlakha, Natasha; Beyea, Mathew; Shofer, Scott L

2011-09-01

Laser has been the main ablative modality in the airways, but a growing experience with endobronchial electrocautery suggests a comparable efficacy and safety profile. To evaluate the efficacy and safety of electrocautery as the primary heat therapy for malignant and benign airway obstruction. A retrospective review of all patients undergoing endobronchial electrocautery, alone or in combination with other airway tools, at Duke University Medical Center between April 2004 and November 2009. Data on efficacy (luminal patency, symptomatic, radiographic, or physiologic improvement) and safety (complication rate) were collected. Ninety-four patients underwent 117 procedures with endobronchial electrocautery for endobronchial malignant and nonmalignant disease. Endoscopic improvement was seen in 94% of cases. Seventy-one percent of patients reported symptomatic improvement. Radiographic studies demonstrated luminal improvement in 78% of patients on chest computed tomography, improved aeration on chest computed tomography and chest x-ray in 63% and 43% of patients, respectively. The rate of major complications was 0.8%, whereas minor complications occurred in 6.8% of cases. There was no perioperative mortality. Endobronchial electrocautery is effective and safe when used as an ablative modality in malignant and benign airway obstruction and has a comparable profile to laser with the advantage of lower cost.

B cell depletion therapy ameliorates autoimmune disease through ablation of IL-6–producing B cells

PubMed Central

Shen, Ping; Brown, Sheila; Lampropoulou, Vicky; Roch, Toralf; Lawrie, Sarah; Fan, Boli; O’Connor, Richard A.; Anderton, Stephen M.; Bar-Or, Amit; Fillatreau, Simon; Gray, David

2012-01-01

B cells have paradoxical roles in autoimmunity, exerting both pathogenic and protective effects. Pathogenesis may be antibody independent, as B cell depletion therapy (BCDT) leads to amelioration of disease irrespective of autoantibody ablation. However, the mechanisms of pathogenesis are poorly understood. We demonstrate that BCDT alleviates central nervous system autoimmunity through ablation of IL-6–secreting pathogenic B cells. B cells from mice with experimental autoimmune encephalomyelitis (EAE) secreted elevated levels of IL-6 compared with B cells from naive controls, and mice with a B cell–specific IL-6 deficiency showed less severe disease than mice with wild-type B cells. Moreover, BCDT ameliorated EAE only in mice with IL-6–sufficient B cells. This mechanism of pathogenesis may also operate in multiple sclerosis (MS) because B cells from MS patients produced more IL-6 than B cells from healthy controls, and this abnormality was normalized with B cell reconstitution after Rituximab treatment. This suggests that BCDT improved disease progression, at least partly, by eliminating IL-6–producing B cells in MS patients. Taking these data together, we conclude that IL-6 secretion is a major mechanism of B cell–driven pathogenesis in T cell–mediated autoimmune disease such as EAE and MS. PMID:22547654

The olfactory pathway mediates sheltering behavior of Caribbean spiny lobsters, Panulirus argus, to conspecific urine signals.

PubMed

Horner, Amy J; Weissburg, Marc J; Derby, Charles D

2008-03-01

The "noses" of diverse taxa are organized into different subsystems whose functions are often not well understood. The "nose" of decapod crustaceans is organized into two parallel pathways that originate in different populations of antennular sensilla and project to specific neuropils in the brain-the aesthetasc/olfactory lobe pathway and the non-aesthetasc/lateral antennular neuropil pathway. In this study, we investigated the role of these pathways in mediating shelter selection of Caribbean spiny lobsters, Panulirus argus, in response to conspecific urine signals. We compared the behavior of ablated animals and intact controls. Our results show that control and non-aesthetasc ablated lobsters have a significant overall preference for shelters emanating urine over control shelters. Thus the non-aesthetasc pathway does not play a critical role in shelter selection. In contrast, spiny lobsters with aesthetascs ablated did not show a preference for either shelter, suggesting that the aesthetasc/olfactory pathway is important for processing social odors. Our results show a difference in the function of these dual chemosensory pathways in responding to social cues, with the aesthetasc/olfactory lobe pathway playing a major role. We discuss our results in the context of why the noses of many animals contain multiple parallel chemosensory systems.

Dependence of calculus retropulsion dynamics on fiber size and radiant exposure during Ho:YAG lithotripsy.

PubMed

Lee, Ho; Ryan, Robert T; Kim, Jeehyun; Choi, Bernard; Arakeri, Navanit V; Teichman, Joel M H; Welch, A J

2004-08-01

During pulsed laser lithotripsy, the calculus is subject to a strong recoil momentum which moves the calculus away from laser delivery and prolongs the operation. This study was designed to quantify the recoil momentum during Ho:YAG laser lithotripsy. The correlation among crater shape, debris trajectory, laser-induced bubble and recoil momentum was investigated. Calculus phantoms made from plaster of Paris were ablated with free running Ho:YAG lasers. The dynamics of recoil action of a calculus phantom was monitored by a high-speed video camera and the laser ablation craters were examined with Optical Coherent Tomography (OCT). Higher radiant exposure resulted in larger ablation volume (mass) which increased the recoil momentum. Smaller fibers produced narrow craters with a steep contoured geometry and decreased recoil momentum compared to larger fibers. In the presence of water, recoil motion of the phantom deviated from that of phantom in air. Under certain conditions, we observed the phantom rocking towards the fiber after the laser pulse. The shape of the crater is one of the major contributing factors to the diminished recoil momentum of smaller fibers. The re-entrance flow of water induced by the bubble collapse is considered to be the cause of the rocking of the phantom.

Conditional Müllercell ablation causes independent neuronal and vascular pathologies in a novel transgenic model.

PubMed

Shen, Weiyong; Fruttiger, Marcus; Zhu, Ling; Chung, Sook H; Barnett, Nigel L; Kirk, Joshua K; Lee, SoRa; Coorey, Nathan J; Killingsworth, Murray; Sherman, Larry S; Gillies, Mark C

2012-11-07

Müller cells are the major glia of the retina that serve numerous functions essential to retinal homeostasis, yet the contribution of Müller glial dysfunction to retinal diseases remains largely unknown. We have developed a transgenic model using a portion of the regulatory region of the retinaldehyde binding protein 1 gene for conditional Müller cell ablation and the consequences of primary Müller cell dysfunction have been studied in adult mice. We found that selective ablation of Müller cells led to photoreceptor apoptosis, vascular telangiectasis, blood-retinal barrier breakdown and, later, intraretinal neovascularization. These changes were accompanied by impaired retinal function and an imbalance between vascular endothelial growth factor-A (VEGF-A) and pigment epithelium-derived factor. Intravitreal injection of ciliary neurotrophic factor inhibited photoreceptor injury but had no effect on the vasculopathy. Conversely, inhibition of VEGF-A activity attenuated vascular leak but did not protect photoreceptors. Our findings show that Müller glial deficiency may be an important upstream cause of retinal neuronal and vascular pathologies in retinal diseases. Combined neuroprotective and anti-angiogenic therapies may be required to treat Müller cell deficiency in retinal diseases and in other parts of the CNS associated with glial dysfunction.

Conditional Müller cell ablation causes independent neuronal and vascular pathologies in a novel transgenic model

PubMed Central

Shen, Weiyong; Fruttiger, Marcus; Zhu, Ling; Chung, Sook H.; Barnett, Nigel L.; Kirk, Joshua K.; Lee, SoRa; Coorey, Nathan J.; Killingsworth, Murray; Sherman, Larry S.; Gillies, Mark C.

2014-01-01

Müller cells are the major glia of the retina that serve numerous functions essential to retinal homeostasis, yet the contribution of Müller glial dysfunction to retinal diseases remains largely unknown. We have developed a transgenic model using a portion of the regulatory region of the retinaldehyde binding protein 1 gene for conditional Müller cell ablation and the consequences of primary Müller cell dysfunction have been studied in adult mice. We found that selective ablation of Müller cells led to photoreceptor apoptosis, vascular telangiectasis, blood-retinal barrier breakdown and, later, intraretinal neovascularization. These changes were accompanied by impaired retinal function and an imbalance between vascular endothelial growth factor-A (VEGF-A) and pigment epithelium derived factor. Intravitreal injection of cilliary neurotrophic factor inhibited photoreceptor injury but had no effect on the vasculopathy. Conversely, inhibition of VEGF-A activity attenuated vascular leak but did not protect photoreceptors. Our findings show that Müller glial deficiency may be an important upstream cause of retinal neuronal and vascular pathologies in retinal diseases. Combined neuroprotective and anti-angiogenic therapies may be required to treat Müller cell deficiency in retinal diseases and in other parts of the central nervous system associated with glial dysfunction. PMID:23136411

Effects of cochlear ablation on choline acetyltransferase activity in the rat cochlear nucleus and superior olive.

PubMed

Jin, Yong-Ming; Godfrey, Donald A; Sun, Yizhe

2005-07-01

Using microdissection and quantitative microassay, choline acetyltransferase (ChAT) activity was mapped in the cochlear nucleus (CN) and in the source nuclei of the olivocochlear bundle, the lateral superior olive and ventral nucleus of the trapezoid body. In control rats, gradients of ChAT activity were found within the major subdivisions of the CN and in the lateral superior olive. These gradients correlated with the known tonotopic organizations, with higher activities corresponding to locations representing higher sound frequencies. No gradient was found in the ventral nucleus of the trapezoid body. In rats surviving 7 days or 1 or 2 months after cochlear ablation, ChAT activity was increased 1 month after ablation in the anteroventral CN by 30-50% in most parts of the lesion-side and by 40% in the contralateral ventromedial part. ChAT activity in the lesion-side posteroventral CN was increased by approximately 40-50% at all survival times. Little change was found in the dorsal CN. Decreases of ChAT activity were also found ipsilaterally in the lateral superior olive and bilaterally in the ventral nucleus of the trapezoid body. Our results suggest that cholinergic neurons are involved in plasticity within the CN and superior olive following cochlear lesions. Copyright 2005 Wiley-Liss, Inc.

Using Meteoric Ablation to Constrain Vertical Transport in the Upper Mesosphere

NASA Astrophysics Data System (ADS)

Plane, J. M. C.; Carrillo-Sánchez, J. D.; Nesvorny, D.; Pokorný, P.; Janches, D.

2016-12-01

Meteoric ablation injects a variety of metals into the upper mesosphere and lower thermosphere, giving rise to layers of metal atoms centered around 90 km. The Na, Fe, K and Ca atom densities are measured accurately using resonance lidars. Since the reaction kinetics of many of the chemical reactions which produce these layers have now been studied in the laboratory, chemistry modules for each of the metals have been developed with a reasonable degree of confidence. When these modules are put into a global high-top model such as NCAR's Whole Atmosphere Community Climate Model (WACCM), a major problem emerges: the injection flux of each of the metals, termed the Meteoric Input Function (MIF), has to be reduced substantially in order to model the observed metal atom densities. For instance, the Na and Fe MIFs need to be reduced by factors of 8 and 14, respectively, compared with the MIFs determined from the lidar-measured vertical fluxes of Na and Fe atoms. The accumulation of meteoric smoke particles in polar ice cores also indicates that the meteoric ablation flux is significantly larger that can be handled in models where vertical transport is solely due to eddy diffusional mixing. Here we derive new Na and Fe MIFs by determining the relative contributions of the known dust sources in the near-Earth environment: Jupiter Family Comets (JFCs), the main asteroid belt, Halley Type comets, and Oort Cloud comets. The mass/velocity/radiant distributions of these cosmic dust populations are Monte Carlo sampled and the elemental ablation rates calculated with the Leeds Chemical Ablation Model. The contribution of each dust source in the Earth's atmosphere is then determined by fitting the measured cosmic spherule accretion rate at the South Pole, and the measured vertical Na and Fe fluxes above 86 km. We conclude that JFCs contribute either 85% or 93% to the total incoming mass, depending on whether infra-red observations of the Zodiacal Dust Cloud by the IRAS or Planck satellites, respectively, are used. The global ablated meteoric mass is then 6 tonnes per day, of which 0.2 tonnes is Na and 2.1 tonnes is Fe. We show that these large fluxes can be accommodated by including wave-driven chemical transport along with eddy diffusion in a 1-D model.

The best of two worlds? Pulmonary vein isolation using a novel radiofrequency ablation catheter incorporating contact force sensing technology and 56-hole porous tip irrigation.

PubMed

Maurer, Tilman; Rottner, Laura; Makimoto, Hisaki; Reissmann, Bruno; Heeger, Christian-H; Lemes, Christine; Fink, Thomas; Riedl, Johannes; Santoro, Francesco; Wohlmuth, Peter; Volkmer, Marius; Mathew, Shibu; Metzner, Andreas; Ouyang, Feifan; Kuck, Karl-Heinz; Sohns, Christian

2018-05-08

This study aimed to evaluate feasibility and safety as well as 1-year clinical outcome of pulmonary vein isolation (PVI) using a unique radiofrequency ablation catheter ("Thermocool SmartTouch SurroundFlow"; STSF) incorporating both, contact force (CF) sensing technology and enhanced tip irrigation with 56 holes, in one device. A total of 110 patients suffering from drug-refractory atrial fibrillation underwent wide area circumferential PVI using either the STSF ablation catheter (75 consecutive patients, study group) or a CF catheter with conventional tip irrigation ("Thermocool SmartTouch", 35 consecutive patients, control group). For each ablation lesion, a target CF of ≥ 10-39 g and a force time integral (FTI) of > 400 g s was targeted. Acute PVI was achieved in all patients with target CF obtained in > 85% of ablation points when using either device. Mean procedure time (131.3 ± 33.7 min in the study group vs. 133.0 ± 42.0 min in the control group; p = 0.99), mean fluoroscopy time (14.0 ± 6 vs. 13.5 ± 6.6 min; p = 0.56) and total ablation time were not significantly different (1751.0 ± 394.0 vs. 1604.6 ± 287.8 s; p = 0.2). However, there was a marked reduction in total irrigation fluid delivery by 51.7% (265.52 ± 64.4 vs. 539.6 ± 118.2 ml; p < 0.01). The Kaplan-Meier estimate 12-month arrhythmia-free survival after the index procedure following a 3-month blanking period was 79.9% (95% CI 70.4%, 90.4%) for the study group and 66.7% for the control group (95% CI 50.2%, 88.5%). This finding did not reach statistical significance (p = 0.18). Major complications occurred in 2/75 patients (2.7%; one pericardial tamponade and one transient ischemic attack) in the study group and no patient in the control group (p = 18). PVI using the STSF catheter is safe and effective and results in beneficial 1-year clinical outcome. The improved tip irrigation leads to a significant reduction in procedural fluid burden.

Post ablation recanalization of varicose veins of the limbs: Comparison ablation method of mechanochemical and laser procedure

NASA Astrophysics Data System (ADS)

Suhartono, R.; Irfan, W.; Wangge, G.; Moenadjat, Y.; Destanto, W. I.

2017-08-01

Endovenous ablation has been performed for varicose veins of the limbs in Indonesia since 2010. Endovenous laser ablation (EVLA) therapy has been performed in Cipto Mangunkusumo Hospital (RSCM) in Jakarta, and mechanochemical ablation (MOCA) has been conducted in Fatmawati Hospital. This was a descriptive analytical study, with a cross-sectional design to analyze post-ablation recanalization after MOCA and EVLA procedures. Patients who had undergone MOCA or EVLA treatment were interviewed 3-18 months after the procedures. All the patients underwent vascular ultrasonography (USG) of the operated limb to assess recanalization. Secondary presurgery data were obtained from the patients’ from patients’ medical records. The clinical characteristics of the subjects were recorded to compare the potential correlation between these characteristics and recanalization post-MOCA and EVLA procedures. All the data were analyzed using SPSS ver. 20.0. The study consisted of 43 limbs: 24 treated by MOCA and 19 treated by EVLA. Most subjects in the MOCA group were <60 years (20/24), and 16 of the subjects were women. In the EVLA group, nine patients were <60 years, and 19 were ≥60 years, 15 of whom were women. The body mass index (BMI) of the majority (18/24) of the subjects in the MOCA group was normal, whereas most of the patients in the EVLA (10/19) group were overweight. In the MOCA group, the largest diameter of the vena saphena magna (VSM) in 20/24 extremities prior to treatment was VSM 4-7 mm, whereas the largest diameter in the EVLA group prior to treatment was >7 mm in 13/19 extremities. In the MOCA group, total recanalization occurred in 2/24 extremities, and partial recanalization occurred in 8/24 extremities. In the EVLA group, total recanalization occurred in 1/19 extremities, and partial recanalization occurred in 3/19 extremities. The association between the clinical characteristics of the patients and recanalization was not statistically significant (p > 0.05). The recanalization tendency was higher in the MOCA group than in the EVLA group. Although there was no statistically significant association between the clinical characteristics of the patients and recanalization, the largest diameter of the VSM presurgery (>7 mm) was higher in 3/4 extremities in the MOCA group, as compared to 3/13 extremities in the EVLA group.

Combination of somatostatin analog, dexamethasone, and standard androgen ablation therapy in stage D3 prostate cancer patients with bone metastases.

PubMed

Koutsilieris, Michael; Mitsiades, Constantine S; Bogdanos, John; Dimopoulos, Theodoros; Karamanolakis, Dimitrios; Milathianakis, Constantine; Tsintavis, Athanassios

2004-07-01

Androgen ablation-refractory prostate cancer patients (stage D3) develop painful bone metastases and limited responsiveness to conventional therapies, hence the lack of universally accepted "gold standard" treatment for this poor prognosis clinical setting. We tested the safety and efficacy in stage D3 patients of the combination hormonal therapy, which combines administration of somatostatin analog and dexamethasone with standard androgen ablation monotherapy (luteinizing-hormone releasing-hormone analog or orchiectomy). Thirty eight patients with stage D3 prostate cancer (mean age 71.8 +/- 5.9 years) continued receiving androgen ablation therapy in combination with oral dexamethasone (4 mg daily for the 1st month of treatment, tapered down to 1 mg daily by the 4th month, with 1 mg daily maintenance dose thereafter) and somatostatin analog (20 mg octreotide i.m. injections every 28 days). Twenty-three of 38 patients (60.5%) receiving this combination regimen had partial responses [PR, >/=50% prostate-specific antigen (PSA) decline], 9 (21.1%) had stable disease, and 7 (18.4%) had progressive disease. In 47.7% (18 of 38) of patients, their serum PSA levels decreased with treatment but did not return to their respective baselines until the end of follow-up (or death from non-prostate cancer-related causes). The median time-to-return to baseline PSA was 12 months (95% CI, 7-17 months), median progression-free survival was 7 months (95% CI, 4.5-9.5 months), median overall survival was 14 months (95% CI, 10.7-17.4 months), and median prostate cancer-specific overall survival (defined as time from onset of combination therapy until prostate cancer-related death) was 16.0 months (95% CI, 11.9-20.1 months). All patients reported significant and durable improvement of bone pain and performance status (for a median duration of 14 months; 95% CI, 9-19 months), without major treatment-related side effects. We observed a statistically significant (P < 0.01) reduction in serum insulin-like growth factor-1 levels at response to the combination therapy. T levels remained suppressed within castration levels at baseline and throughout therapy, including relapse. The combination therapy of dexamethasone plus somatostatin analog and standard androgen ablation manipulation produces objective clinical responses and symptomatic improvement in androgen ablation-refractory refractory prostate cancer patients.

Thermal and mechanical high-intensity focused ultrasound: perspectives on tumor ablation, immune effects and combination strategies.

PubMed

van den Bijgaart, Renske J E; Eikelenboom, Dylan C; Hoogenboom, Martijn; Fütterer, Jurgen J; den Brok, Martijn H; Adema, Gosse J

2017-02-01

Tumor ablation technologies, such as radiofrequency-, cryo- or high-intensity focused ultrasound (HIFU) ablation will destroy tumor tissue in a minimally invasive manner. Ablation generates large volumes of tumor debris in situ, releasing multiple bio-molecules like tumor antigens and damage-associated molecular patterns. To initiate an adaptive antitumor immune response, antigen-presenting cells need to take up tumor antigens and, following activation, present them to immune effector cells. The impact of the type of tumor ablation on the precise nature, availability and suitability of the tumor debris for immune response induction, however, is poorly understood. In this review, we focus on immune effects after HIFU-mediated ablation and compare these to findings using other ablation technologies. HIFU can be used both for thermal and mechanical destruction of tissue, inducing coagulative necrosis or subcellular fragmentation, respectively. Preclinical and clinical results of HIFU tumor ablation show increased infiltration and activation of CD4 + and CD8 + T cells. As previously observed for other types of tumor ablation technologies, however, this ablation-induced enhanced infiltration alone appears insufficient to generate consistent protective antitumor immunity. Therapies combining ablation with immune stimulation are therefore expected to be key to boost HIFU-induced immune effects and to achieve systemic, long-lasting, antitumor immunity.

Atrial fibrillation ablation using cryoballoon technology: Recent advances and practical techniques.

PubMed

Chen, Shaojie; Schmidt, Boris; Bordignon, Stefano; Bologna, Fabrizio; Perrotta, Laura; Nagase, Takahiko; Chun, K R Julian

2018-04-16

Atrial fibrillation (AF) affects 1-2% of the population, and its prevalence is estimated to double in the next 50 years as the population ages. AF results in impaired patients' life quality, deteriorated cardiac function, and even increased mortality. Antiarrhythmic drugs frequently fail to restore sinus rhythm. Catheter ablation is a valuable treatment approach for AF, even as a first-line therapy strategy in selected patients. Effective electrical pulmonary vein isolation (PVI) is the cornerstone of all AF ablation strategies. Use of radiofrequency (RF) catheter in combination of a three-dimensional electroanatomical mapping system is the most established ablation approach. However, catheter ablation of AF is challenging even sometimes for experienced operators. To facilitate catheter ablation of AF without compromising the durability of the pulmonary vein isolation, "single shot" ablation devices have been developed; of them, cryoballoon ablation, is by far the most widely investigated. In this report, we review the current knowledge of AF and discuss the recent evidence in catheter ablation of AF, particularly cryoballoon ablation. Moreover, we review relevant data from the literature as well as our own experience and summarize the key procedural practical techniques in PVI using cryoballoon technology, aiming to shorten the learning curve of the ablation technique and to contribute further to reduction of the disease burden. © 2018 Wiley Periodicals, Inc.

Eye-Pursuit and Reafferent Head Movement Signals Carried by Pursuit Neurons in the Caudal Part of the Frontal Eye Fields during Head-Free Pursuit

PubMed Central

Kasahara, Satoshi; Akao, Teppei; Kurkin, Sergei; Peterson, Barry W.

2009-01-01

Eye and head movements are coordinated during head-free pursuit. To examine whether pursuit neurons in frontal eye fields (FEF) carry gaze-pursuit commands that drive both eye-pursuit and head-pursuit, monkeys whose heads were free to rotate about a vertical axis were trained to pursue a juice feeder with their head and a target with their eyes. Initially the feeder and target moved synchronously with the same visual angle. FEF neurons responding to this gaze-pursuit were tested for eye-pursuit of target motion while the feeder was stationary and for head-pursuit while the target was stationary. The majority of pursuit neurons exhibited modulation during head-pursuit, but their preferred directions during eye-pursuit and head-pursuit were different. Although peak modulation occurred during head movements, the onset of discharge usually was not aligned with the head movement onset. The minority of neurons whose discharge onset was so aligned discharged after the head movement onset. These results do not support the idea that the head-pursuit–related modulation reflects head-pursuit commands. Furthermore, modulation similar to that during head-pursuit was obtained by passive head rotation on stationary trunk. Our results suggest that FEF pursuit neurons issue gaze or eye movement commands during gaze-pursuit and that the head-pursuit–related modulation primarily reflects reafferent signals resulting from head movements. PMID:18483002

The Potential for Tumor Suppressor Gene Therapy in Head and Neck Cancer

PubMed Central

Birkeland, Andrew C.; Ludwig, Megan L.; Spector, Matthew E.; Brenner, J. Chad

2016-01-01

Head and neck squamous cell carcinoma remains a highly morbid and fatal disease. Importantly, genomic sequencing of head and neck cancers has identified frequent mutations in tumor suppressor genes. While targeted therapeutics increasingly are being investigated in head and neck cancer, the majority of these agents are against overactive/overexpressed oncogenes. Therapy to restore lost tumor suppressor gene function remains a key and under-addressed niche in trials for head and neck cancer. Recent advances in gene editing have captured the interest of both the scientific community and the public. As our technology for gene editing and gene expression modulation improves, addressing lost tumor suppressor gene function in head and neck cancers is becoming a reality. This review will summarize new techniques, challenges to implementation, future directions, and ethical ramifications of gene therapy in head and neck cancer. PMID:26896601

Head Pose Estimation on Eyeglasses Using Line Detection and Classification Approach

NASA Astrophysics Data System (ADS)

Setthawong, Pisal; Vannija, Vajirasak

This paper proposes a unique approach for head pose estimation of subjects with eyeglasses by using a combination of line detection and classification approaches. Head pose estimation is considered as an important non-verbal form of communication and could also be used in the area of Human-Computer Interface. A major improvement of the proposed approach is that it allows estimation of head poses at a high yaw/pitch angle when compared with existing geometric approaches, does not require expensive data preparation and training, and is generally fast when compared with other approaches.

Do head-restraints protect the neck from whiplash injuries?

PubMed Central

Morris, F

1989-01-01

Over an 11-month period a study was made of all patients presenting to an accident and emergency department who had sustained whiplash as a result of rear-bumper impacts. The patients were analysed with respect to the presence of head-restraints in their vehicles. A significant increase in the incidence of whiplash was found in patients whose vehicles did not have head-restraints fitted. Legislation requiring all passenger cars to have head-restraints fitted as standard would have a major impact in reducing the number of whiplash injuries sustained in rear bumper impacts. PMID:2712983

Vergence-mediated modulation of the human horizontal vestibulo-ocular reflex is eliminated by a partial peripheral gentamicin lesion.

PubMed

Migliaccio, Americo A; Minor, Lloyd B; Carey, John P

2004-11-01

The angular vestibulo-ocular reflex normally has an increased response during vergence on a near target. Surgical unilateral vestibular deafferentation reduces the horizontal vestibulo-ocular reflex (VOR) in response to far target viewing and eliminates this vergence effect. Intratympanic gentamicin treatment reduces VOR gain during far viewing, but the reduction is less severe than that after unilateral vestibular deafferentation. We sought to determine how gentamicin would affect vergence-mediated modulation of the VOR. The VOR in response to passive head impulses in the horizontal plane while viewing a far (124 cm) or near (15 cm) target was evaluated in 11 subjects following intratympanic gentamicin treatment. Three of these subjects had also been tested immediately prior to receiving gentamicin. The impulses were low amplitude (approximately 20 degrees ), high velocity (approximately 150 degrees /s), high acceleration (approximately 3,000 degrees /s2) horizontal head rotations administered manually by the investigator. Binocular eye and head velocity were recorded using the scleral search coil technique. The VOR gain was defined as eye velocity divided by inverted head velocity. Prior to intratympanic gentamicin, the VOR gain during rotations to either side was symmetric and showed the same vergence-mediated increase. Following gentamicin, head impulses towards the untreated side yielded VOR gains of 0.91+/-0.12 while viewing a far target and 1.27+/-0.22 while viewing a near target, an increase of 33%. Head impulses towards the treated side produced a hypometric VOR with no increase between far and near viewing. The average latency of the VOR was 7.6+/-2.5 ms towards the untreated side for either near or far viewing and 20.7+/-13.1 ms towards the treated side for either near or far viewing. Our findings show that a peripheral lesion caused by gentamicin does not ablate the VOR but does eliminate a component of the vestibular signal that is necessary for vergence-mediated modulation of the VOR. Gentamicin has preferential toxicity for the hair cells in the central zone of the crista, where irregular afferents predominate. Our findings are consistent with the hypothesis that irregular afferents provide the necessary signal for vergence-mediated modulation of the VOR.

[The clinical impact of artery-first approach combined with vascular resection and reconstruction in the treatment of pancreatic head carcinoma].

PubMed

Huang, J L; Li, W G; Chen, F Z; Su, Z J; Li, F M; Liu, B

2017-03-23

Objective: To evaluate the application of artery first, combined vascular resection and reconstruction in the treatment of pancreatic head carcinoma. Methods: The clinical data of 13 patients with pancreatic head cancer were retrospectively analyzed from February 2014 to March 2016 in the Affiliated Hospital of Xiamen University. Preoperative computed tomography of high resolution layer or magnetic resonance imaging examination demonstrated pancreatic head carcinoma, as well as close adhesion, stenosis, compression or displacement of superior mesenteric vein or portal vein wall. In the operation, the artery first approach was used and the whole arterial blood supply in the head of the pancreas was fully exposed and interdicted. Finally, en block resection and vascular resection and reconstruction was adopted. Results: 12 of 13 patients had pancreatoduodenectomy synchronously with vascular resection and reconstruction; the other patient had these two surgery sequentially. Four patients received blood vessel wedge resection, five had segmental resection combined with end to end suture, and four had segmental resection combined with artificial vascular graft reconstruction. Operation time was (327.2±65.5) minutes, and the amount of blood loss was (472.6±226.4) millilitres. One patient suffered from delayed gastric emptying, and two patients had pancreatic fistula. All patients recovered from postoperative complications by conservative treatment. No patients developed biliary fistula, gastrointestinal fistula, abdominal infection, pulmonary infection, diarrhea, hypoglycemia or other complications, and none died in perioperative period. Postoperative pathological findings confirmed the diagnosis of pancreatic ductal adenocarcinoma. Mean tumor diameter was (4.2±1.5)cm, and (3.8±1.5) metastasis were found in (13.6±2.5) resected lymph nodes. In 11 cases, the tumor cells were found in the outer membrane of blood vessels, 2 cases were found to have tumor invasion in the inner membrane, and all the resection margins were negative. All patients were followed up, and 2 patients died of liver metastasis 11 months and 18 months after operation, respectively. One patient survived with local recurrence of tumor 13 months after surgery. Other patients had no tumor recurrence and metastasis. Conclusions: The artery first approch combined vascular resection and reconstruction is safe effective and feasible in the treatment of pancreatic head carcinoma. It can improve the ablation rate of pancreatoduodenectomy.

Time-resolved investigations of the non-thermal ablation process of graphite induced by femtosecond laser pulses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kalupka, C., E-mail: christian.kalupka@llt.rwth-aachen.de; Finger, J.; Reininghaus, M.

2016-04-21

We report on the in-situ analysis of the ablation dynamics of the, so-called, laser induced non-thermal ablation process of graphite. A highly oriented pyrolytic graphite is excited by femtosecond laser pulses with fluences below the classic thermal ablation threshold. The ablation dynamics are investigated by axial pump-probe reflection measurements, transversal pump-probe shadowgraphy, and time-resolved transversal emission photography. The combination of the applied analysis methods allows for a continuous and detailed time-resolved observation of the non-thermal ablation dynamics from several picoseconds up to 180 ns. Formation of large, μm-sized particles takes place within the first 3.5 ns after irradiation. The following propagation ofmore » ablation products and the shock wave front are tracked by transversal shadowgraphy up to 16 ns. The comparison of ablation dynamics of different fluences by emission photography reveals thermal ablation products even for non-thermal fluences.« less

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

PubMed

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.

Through-the-thickness selective laser ablation of ceramic coatings on soda-lime glass

NASA Astrophysics Data System (ADS)

Romoli, L.; Khan, M. M. A.; Valentini, M.

2017-05-01

This paper investigates through-thickness laser ablation characteristics of ceramic coating deposited on the bottom surface of the soda-lime glass substrate. Experimental studies were focused on determining the effects of energy density, hatch distance and coating color on the ablation completion index. Effect of glass thickness was also tested to verify the robustness of the designed process. Up to a certain threshold limit, the ablation completion index is energy-limited and has an inverse U-shape relationship with the energy density input. Since greater hatch distance means faster ablation and lesser ablation completion index, there must be a tradeoff between ablation completion index and hatch distance. During through-thickness laser ablation of ceramic coating, energy density input should be in the range of 0.049 J/mm2 - 0.251 J/mm2 for black ceramic coating and 0.112 J/mm2 - 0.251 J/mm2 for other coatings. Finally, the designed process is capable of ablating the ceramic coating effectively through varied thickness.

Pulsed laser ablation of IC packages for device failure analyses

NASA Astrophysics Data System (ADS)

Hong, Ming Hui; Mai, ZhiHong; Chen, G. X.; Thiam, Thomas; Song, Wen D.; Lu, Yongfeng; Soh, Chye E.; Chong, Tow Chong

2002-06-01

Pulsed laser ablation of mold compounds for IC packaging in air and with steam assistance is investigated. It is applied to decap IC packages and expose computer CPU dies for the device failure analyses. Compared with chemical decapping, the laser ablation has advantages of being fast speed, non- contact and dry processing. Laser ablation with the steam assistance results in higher ablation rate and wider ablated crater with much smoother surface morphology. It implies that the steam assisted laser ablation can achieve a faster and better quality laser processing. Audible acoustic wave and plasma optical signal diagnostics are also carried out to have a better understanding of the mechanisms behind. Light wavelength and laser fluence applied in the decapping are two important parameters. The 532 nm Nd:YAG laser decapping at a low laser fluence can achieve a large decapping area with a fine ablation profile. IC packages decapped by the laser ablation show good quality for the device failure analyses.

Effect of bromine-dopant on radiation-driven Rayleigh-Taylor instability in plastic foil

NASA Astrophysics Data System (ADS)

Xu, Binbin; Ma, Yanyun; Yang, Xiaohu; Tang, Wenhui; Ge, Zheyi; Zhao, Yuan; Ke, Yanzhao; Kawata, Shiego

2017-10-01

Effects of bromine (Br) dopant on the growth of radiation-driven ablative Rayleigh-Taylor instability (RTI) in plastic foils are studied by radiation hydrodynamics simulations and theoretical analysis. It is found that the Br-dopant in plastic foil reduces the seed of ablative RTI. The main reasons of the reduction are attributed to the smaller oscillation amplitude of ablative Richtmyer-Meshkov instability (RMI) induced by the smaller post-shock sound speed, and the smaller oscillation frequency of ablative RMI induced by the smaller ablation velocity and blow-off plasma velocity. The Br-dopant also decreases the linear growth rate of ablative RTI due to the smaller acceleration. Treating the perturbation growth as a function of foil’s displacement, the perturbation growth would increase in Br-doped foil at the phase of ablative RTI, which is attributed to the decrease of the ablation velocity and the density gradient scale length. The results are helpful for further understanding the influence of high-Z dopant on the radiation-driven ablative RTI.

Effects of material composition on the ablation performance of low density elastomeric ablators

NASA Technical Reports Server (NTRS)

Tompkins, S. S.; Kabana, W. P.

1973-01-01

The ablation performance of materials composed of various concentrations of nylon, hollow silica spheres, hollow phenolic spheres, and four elastomeric resins was determined. Both blunt-body and flat-panel specimens were used, the cold-wall heating-rate ranges being 0.11 to 0.8 MW/sq m, respectively. The corresponding surface pressure ranges for these tests were 0.017 to 0.037 atmosphere and 0.004 to 0.005 atmosphere. Some of the results show that (1) the addition of nylon significantly improved the ablation performance, but the nylon was not compatible with one resin system; (2) panel and blunt-body specimen data do not show the same effect of phenolic sphere content on ablation effectiveness; and (3) there appears to be an optimum concentration of hollow silica spheres for good ablation performance. The composition of an efficient, nonproprietary ablator for lifting body application is identified and the ablation performance of this ablator is compared with the performance of three commercially available materials.

Determination of excimer laser ablation rate of the human cornea using in vivo Scheimpflug videography.

PubMed

Huebscher, H J; Genth, U; Seiler, T

1996-01-01

To determine in vivo the amount of human corneal tissue removed by each excimer laser pulse, the so-called ablation rate, during photorefractive keratectomy (PRK). There is confusion in the literature because the experimentally determined ablation rate of 0.4 to 0.5 microns per pulse differs from the nominal ablation rate of 0.23 to 0.3 microns per pulse, which is the value used in clinical procedures. Eleven eyes of 11 patients were treated with PRK for correction of myopia. The corneal curvature was determined by Scheimpflug videography before and immediately after surgery. Starting from this curvature change, the authors calculated the real ablation rate. The real ablation rate is coincident with the nominal ablation rate and differs significantly from the ablation rate derived from deep keratectomy experiments. The outer layers of the cornea show significantly different ablation behavior than the deeper stroma. This information has clinical relevance for the predictability of intrastromal excimer laser procedures.