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Pulse radiofrequency

F Minary, D Rabus, G Martin, J-M Friedt
Stroboscopy provides an energy and computationally efficient means of sampling radiofrequency and microwave signals assumed to be reproducible under external excitation. While well known for impulse mode RADAR receivers, we here investigate its use for interrogating surface acoustic wave (SAW) transducers acting as passive cooperative targets. Amongst the originality of the implementation is the need to keep phase coherence between successive pulse generations which last up to tens of the radiofrequency periods to optimally transfer energy to the transducer...
September 2016: Review of Scientific Instruments
Simone A Winkler, Paul A Picot, Michael M Thornton, Brian K Rutt
PURPOSE: To develop a new method capable of directly measuring specific absorption rate (SAR) deposited in tissue using the thermoacoustic signal induced by short radiofrequency (RF) pulse excitation. THEORY: A detailed model based on the thermoacoustic wave generation and propagation is presented. METHODS: We propose a new concept for direct measurement of SAR, to be used as a safety assessment/monitoring tool for MRI. The concept involves the use of short bursts of RF energy and the measurement of the resulting thermoacoustic excitation pattern by an array of ultrasound transducers, followed by image reconstruction to yield the 3D SAR distribution...
October 25, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Vincent Gras, Alexandre Vignaud, Alexis Amadon, Franck Mauconduit, Denis Le Bihan, Nicolas Boulant
PURPOSE: A multispoke specific absorption rate (SAR) -aware pulse design approach for homogeneous multiple-slice small and large flip angle (FA) excitations with parallel transmission is proposed. The approach aims at optimizing in a slice-specific manner the spokes locations and radiofrequency pulses. METHODS: The problem is posed as a set of slice-specific magnitude-least-squares problems, linked together by hardware and SAR constraints, and solved jointly using an active-set algorithm...
October 23, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Desmond H Y Tse, Christopher J Wiggins, Benedikt A Poser
PURPOSE: In order to fully benefit from the improved signal-to-noise and contrast-to-noise ratios at 9.4T, the challenges of B1+ inhomogeneity and the long acquisition time of high-resolution 2D gradient-recalled echo (GRE) imaging were addressed. THEORY AND METHODS: Flip angle homogenized excitations were achieved by parallel transmission (pTx) of 3-spoke pulses, designed by magnitude least-squares optimization in a slice-by-slice fashion; the acquisition time reduction was achieved by simultaneous multislice (SMS) pulses...
October 23, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
M Arcan Ertürk, Xiaoping Wu, Yiğitcan Eryaman, Pierre-François Van de Moortele, Edward J Auerbach, Russell L Lagore, Lance DelaBarre, J Thomas Vaughan, Kâmil Uğurbil, Gregor Adriany, Gregory J Metzger
PURPOSE: To explore the potential of performing body imaging at 10.5 Tesla (T) compared with 7.0T through evaluating the transmit/receive performance of similarly configured dipole antenna arrays. METHODS: Fractionated dipole antenna elements for 10.5T body imaging were designed and evaluated using numerical simulations. Transmit performance of antenna arrays inside the prostate, kidneys and heart were investigated and compared with those at 7.0T using both phase-only radiofrequency (RF) shimming and multi-spoke pulses...
October 21, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Hong Shang, Subramaniam Sukumar, Cornelius von Morze, Robert A Bok, Irene Marco-Rius, Adam Kerr, Galen D Reed, Eugene Milshteyn, Michael A Ohliger, John Kurhanewicz, Peder E Z Larson, John M Pauly, Daniel B Vigneron
PURPOSE: Balanced steady-state free precession (bSSFP) sequences can provide superior signal-to-noise ratio efficiency for hyperpolarized (HP) carbon-13 ((13) C) magnetic resonance imaging by efficiently utilizing the nonrecoverable magnetization, but managing their spectral response is challenging in the context of metabolic imaging. A new spectrally selective bSSFP sequence was developed for fast imaging of multiple HP (13) C metabolites with high spatiotemporal resolution. THEORY AND METHODS: This novel approach for bSSFP spectral selectivity incorporates optimized short-duration spectrally selective radiofrequency pulses within a bSSFP pulse train and a carefully chosen repetition time to avoid banding artifacts...
October 21, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Korgün Ökmen, Burcu Metin Ökmen
This study aims to investigate the efficacy of three different percutaneous intradiscal therapies in patients with chronic low back pain (CLBP) due to lumbar disc herniation (LDH). Medical files of a total of 120 patients who received percutaneous intradiscal therapy were retrospectively analyzed. All patients were divided into three groups: group L: diode laser (n = 40), group R: radiofrequency (RF) (n = 40), and group P: pulsed radiofrequency (PRF) (n = 40). The visual analogue scale (VAS) and Oswestry Disability Index (ODI) scores were calculated at 1, 3, 6, and 12 months for all patients...
October 21, 2016: Lasers in Medical Science
Bhagya Ranjan Jena, Anil Paswan, Yashpal Singh, Sandeep Loha, Anil Prasad Singh, Virendra Rastogi
BACKGROUND: Radiofrequency (RF) is a minimally invasive target-selective technique that has been used with success for many years in the treatment of different pathologies, such as low back pain, trigeminal neuralgia, and others. AIM: The aim of this study is to compare different mode of RF - continuous RF (CRF) versus pulsed RF (PRF) along with steroid in the management of low back pain of discogenic origin. SETTING AND DESIGN: Prospective, randomized, double-blind trial...
September 2016: Anesthesia, Essays and Researches
Fei Wang, Qian Zhou, Lizu Xiao, Juan Yang, Donglin Xong, Disen Li, LiPing Liu, Sigdha Ancha, Jianguo Cheng
BACKGROUND: We demonstrated a combination of pulsed radiofrequency (PRF) and cervical nerve root block (CNRB) via a posterior approach was superior to a transforaminal epidural steroid injection through the anterolateral approach for cervical radicular pain in a previous study. This randomized trial was conducted to determine the comparative efficacy between CNRB, PRF, and CNRB + PRF for cervical radicular pain. METHODS: A prospective and randomized design was used in this study...
October 14, 2016: Pain Practice: the Official Journal of World Institute of Pain
Won Soek Chae, Sang Hyun Kim, Sung Hwan Cho, Joon Ho Lee, Mi Sun Lee
The superficial peroneal nerve is vulnerable to damage from ankle sprain injuries and fractures as well as surgery to this region. And it is also one of the most commonly involved nerves in complex regional pain syndrome type II in the foot and ankle region. We report two cases of ultrasound-guided pulsed radiofrequency treatment of superficial peroneal nerve for reduction of allodynia in CRPS patients.
October 2016: Korean Journal of Pain
Andrew J Coristine, Jerome Yerly, Matthias Stuber
BACKGROUND: Two-dimensional (2D) spatially selective radiofrequency (RF) pulses may be used to excite restricted volumes. By incorporating a "pencil beam" 2D pulse into a T2-Prep, one may create a "2D-T2-Prep" that combines T2-weighting with an intrinsic outer volume suppression. This may particularly benefit parallel imaging techniques, where artefacts typically originate from residual foldover signal. By suppressing foldover signal with a 2D-T2-Prep, image quality may therefore improve...
2016: PloS One
Jeremy W Gordon, Eugene Milshteyn, Irene Marco-Rius, Michael Ohliger, Daniel B Vigneron, Peder E Z Larson
PURPOSE: The purpose of this work was to explore the impact of slice profile effects on apparent diffusion coefficient (ADC) mapping of hyperpolarized (HP) substrates. METHODS: Slice profile effects were simulated using a Gaussian radiofrequency (RF) pulse with a variety of flip angle schedules and b-value ordering schemes. A long T1 water phantom was used to validate the simulation results, and ADC mapping of HP [(13) C,(15) N2 ]urea was performed on the murine liver to assess these effects in vivo...
October 13, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Chenlong Liao, Massimiliano Visocchi, Min Yang, Pengfei Liu, Shiting Li, Wenchuan Zhang
BACKGROUND: Pain relief comparable to radiofrequency thermocoagulation (RFT) alone and fewer side effects have been achieved by combination treatment with pulsed radiofrequency (PRF) and short-duration RFT in trigeminal neuralgia (TN). CASE DESCRIPTION: We report the successful management of recurrent TN following RFT with single PRF in two patients. The RFT treatment was performed in 2-3 cycles for each division with the lesion setting at 75-80°C for 90 s. The PRF treatment was applied for 120 s with a generator output of 45 V, not exceeding a temperature of 42°C at the tip of the electrode...
October 8, 2016: World Neurosurgery
Giuseppe Stabile, Matteo Anselmino, Ezio Soldati, Ermengildo De Ruvo, Francesco Solimene, Assunta Iuliano, Luigi Sciarra, Maria Grazia Bongiorni, Leonardo Calò, Fiorenzo Gaita
PURPOSE: Left atrial volume (LA) and pulmonary vein (PV) anatomy may potentially relate to technical challenges in achieving stable and effective catheter position in case of atrial fibrillation (AF) ablation by means of "one-shot" catheters. The aim of this study was to investigate whether LA volume and PV anatomy, evaluated by computed tomography (CT) or magnetic resonance (MR) prior to ablation, predict acute and midterm outcome of AF ablation by nMARQ™. METHODS: We included 75 patients (mean age 58 ± 11 years, 67 % male) with symptomatic paroxysmal AF...
October 6, 2016: Journal of Interventional Cardiac Electrophysiology: An International Journal of Arrhythmias and Pacing
Jin Young Lee, Woo Seog Sim, Ryung A Kang, Eun Kyung Lee, Jae Young Yang, Dae Yoon Kim
Erythromelalgia is often refractory and resistant to many forms of treatment. Numerous therapeutic options have been tried, but effective treatment remains elusive. The sympathetic nervous system has been involved in various painful conditions of neuropathic, vascular, and visceral origin. Sympathetic block is helpful in making a diagnosis and managing pain. We report a case of excellent pain relief after lumbar sympathetic pulsed radiofrequency treatment in a patient with primary erythromelalgia of the lower extremities...
October 4, 2016: Pediatric Dermatology
Chia-Kai Liu, Wen-Tzu Liao, Yu-Chi Chu, Chien-Hui Yang, Kuan-Hung Chen, Chih-Hsien Wu, Chung-Ren Lin
BACKGROUND:  Pulsed radiofrequency (PRF) treatment offers pain relief for patients suffering from chronic pain who do not respond well to conventional treatments. We tested whether PRF treatment attenuated complete Freund's adjuvant (CFA)-induced inflammatory pain. Epigenetic modification of potassium-chloride cotransporter 2 (KCC2) gene expression was examined to elucidate the potential contributing mechanism. METHODS:  Male Sprague-Dawley rats were injected with CFA into the plantar surface of the left hind paw to induce inflammation...
September 28, 2016: Pain Medicine: the Official Journal of the American Academy of Pain Medicine
Konstantin Tamarov, Wujun Xu, Liubov Osminkina, Sergey Zinovyev, Pasi Soininen, Andrey Kudryavtsev, Maxim Gongalsky, Azha Gaydarova, Ale Närvänen, Victor Timoshenko, Vesa-Pekka Lehto
: One critical functionality of the carrier system utilized in targeted drug delivery is its ability to trigger the release of the therapeutic cargo once the carrier has reached its target. External triggering is an alluring approach as it can be applied in a precise spatiotemporal manner. In the present study, we achieved external triggering through the porous silicon (PSi) nanoparticles (NPs) by providing a pulse of infrared or radiofrequency radiation. The NPs were grafted with a temperature responsive polymer whose critical temperature was tailored to be slightly above 37°C...
November 10, 2016: Journal of Controlled Release: Official Journal of the Controlled Release Society
Vincent F Miccio, Rohit Navlani, Jaclyn H Bonder, Jaspal Ricky Singh
No abstract text is available yet for this article.
September 2016: Pain Physician
QiaoDong Huang, XiaoMing Liu, JinSheng Chen, CunJu Bao, DongYang Liu, ZeZang Fang, XiaoYu Liang, ZhenHe Lu, Li Wan
BACKGROUND: Trigeminal neuralgia (TN) is a pain appearing in the ophthalmic (V1), maxillary (V2), and mandibular (V3) trigeminal branches. Pharmacologic treatment is the first line for TN; however, many patients prefer to receive minimally invasive treatment rather than medicine because of intolerable side effects. Thermocoagulation radiofrequency (TRF) is a minimally invasive treatment that has been shown to effectively treat the maxillary (V2) and mandibular (V3) divisions, but the safety of TRF treatment of the ophthalmic (V1) division has been controversial...
September 2016: Pain Physician
David Arsanious, Emmanuel Gage, Jonathon Koning, Mazin Sarhan, Gassan Chaiban, Mohammed Almualim, Joseph Atallah
BACKGROUND: One of the potential side effects with radiofrequency ablation (RFA) includes painful cutaneous dysesthesias and increased pain due to neuritis or neurogenic inflammation. This pain may require the prescription of opioids or non-opioid analgesics to control post-procedural pain and discomfort. OBJECTIVES: The goal of this study is to compare post-procedural pain scores and post-procedural oral analgesic use in patients receiving continuous thermal radiofrequency ablation versus patients receiving pulsed dose radiofrequency immediately followed by continuous thermal radiofrequency ablation for zygopophaseal joint disease...
September 2016: Pain Physician
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