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Mr thermometry

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https://www.readbyqxmd.com/read/29215150/mri-monitoring-of-focused-ultrasound-sonications-near-metallic-hardware
#1
Hans Weber, Pejman Ghanouni, Aurea Pascal-Tenorio, Kim Butts Pauly, Brian A Hargreaves
PURPOSE: To explore the temperature-induced signal change in two-dimensional multi-spectral imaging (2DMSI) for fast thermometry near metallic hardware to enable MR-guided focused ultrasound surgery (MRgFUS) in patients with implanted metallic hardware. METHOD: 2DMSI was optimized for temperature sensitivity and applied to monitor focus ultrasound surgery (FUS) sonications near metallic hardware in phantoms and ex vivo porcine muscle tissue. Further, we evaluated its temperature sensitivity for in vivo muscle in patients without metallic hardware...
December 7, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/29193144/simulating-thermal-effects-of-mr-guided-focused-ultrasound-in-cortical-bone-and-its-surrounding-tissue
#2
Thomas J Hudson, Thomas Looi, Samuel Pichardo, Joao Amaral, Michael Temple, James M Drake, Adam C Waspe
PURPOSE: Magnetic resonance guided focused ultrasound (MRgFUS) is emerging as a treatment alternative for osteoid osteoma and painful bone metastases. This study describes a new simulation platform that predicts the distribution of heat generated by MRgFUS when applied to bone tissue. METHODS: Calculation of the temperature distribution was performed using two mathematical models. The first determined the propagation and absorption of acoustic energy through each medium, and this was performed using a multi-layered approximation of the Rayleigh integral...
November 28, 2017: Medical Physics
https://www.readbyqxmd.com/read/29115692/a-spiral-based-volumetric-acquisition-for-mr-temperature-imaging
#3
Samuel W Fielden, Xue Feng, Li Zhao, G Wilson Miller, Matthew Geeslin, Robert F Dallapiaza, W Jeffrey Elias, Max Wintermark, Kim Butts Pauly, Craig H Meyer
PURPOSE: To develop a rapid pulse sequence for volumetric MR thermometry. METHODS: Simulations were carried out to assess temperature deviation, focal spot distortion/blurring, and focal spot shift across a range of readout durations and maximum temperatures for Cartesian, spiral-out, and retraced spiral-in/out (RIO) trajectories. The RIO trajectory was applied for stack-of-spirals 3D imaging on a real-time imaging platform and preliminary evaluation was carried out compared to a standard 2D sequence in vivo using a swine brain model, comparing maximum and mean temperatures measured between the two methods, as well as the temporal standard deviation measured by the two methods...
November 8, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/29017073/noninvasive-detection-of-focal-brain-hyperthermia-related-to-continuous-epileptic-activities-using-proton-mr-spectroscopy
#4
Daichi Sone, Naoki Ikegaya, Akio Takahashi, Kaoru Sumida, Miho Ota, Takashi Saito, Yukio Kimura, Hiroshi Matsuda, Noriko Sato
Recent studies using rat models suggested that epileptic discharges (EDs) can induce focal brain hyperthermia, but such ED-related hyperthermia has not been confirmed in humans. We examined hyperthermia of the focus of epilepsy using noninvasive proton magnetic resonance spectroscopy ((1)H-MRS) thermometry. We recruited six pediatric patients with refractory daily seizures, continuous interictal epileptic discharges, and concordant focus lesions on MRI who had undergone comprehensive presurgical exams. (1)H-MRS thermometry calculated the temperatures of the presumed epileptogenic lesions, and we examined the contralateral counterparts in each patient as controls...
October 6, 2017: Epilepsy Research
https://www.readbyqxmd.com/read/28944490/hybrid-ultrasound-mr-guided-hifu-treatment-method-with-3d-motion-compensation
#5
Zarko Celicanin, Gibran Manasseh, Lorena Petrusca, Klaus Scheffler, Vincent Auboiroux, Lindsey A Crowe, Jean-Noel Hyacinthe, Yutaka Natsuaki, Francesco Santini, Christoph D Becker, Sylvain Terraz, Oliver Bieri, Rares Salomir
PURPOSE: Treatments using high-intensity focused ultrasound (HIFU) in the abdominal region remain challenging as a result of respiratory organ motion. A novel method is described here to achieve 3D motion-compensated ultrasound (US) MR-guided HIFU therapy using simultaneous ultrasound and MRI. METHODS: A truly hybrid US-MR-guided HIFU method was used to plan and control the treatment. Two-dimensional ultrasound was used in real time to enable tracking of the motion in the coronal plane, whereas an MR pencil-beam navigator was used to detect anterior-posterior motion...
September 24, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28935624/the-brain-thermal-response-as-a-potential-neuroimaging-biomarker-of-cerebrovascular-impairment
#6
C C Fleischer, J Wu, D Qiu, S-E Park, F Nahab, S Dehkharghani
BACKGROUND AND PURPOSE: Brain temperature is critical for homeostasis, relating intimately to cerebral perfusion and metabolism. Cerebral thermometry is historically challenged by the cost and invasiveness of clinical and laboratory methodologies. We propose the use of noninvasive MR thermometry in patients with cerebrovascular disease, hypothesizing the presence of a measurable brain thermal response reflecting the tissue hemodynamic state. MATERIALS AND METHODS: Contemporaneous imaging and MR thermometry were performed in 10 patients (32-68 years of age) undergoing acetazolamide challenge for chronic, anterior circulation steno-occlusive disease...
November 2017: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/28922117/magnetic-resonance-mediated-radiofrequency-ablation
#7
Yik-Kiong Hue, Alexander R Guimaraes, Ouri Cohen, Erez Nevo, Abraham Roth, Jerome L Ackerman, Jerome L Ackerman
OBJECTIVE: To introduce magnetic resonance mediated radiofrequency ablation (MR-RFA), in which the MRI scanner uniquely serves both diagnostic and therapeutic roles. In MR-RFA scanner-induced RF heating is channeled to the ablation site via a Larmor frequency RF pickup device and needle system, and controlled via the pulse sequence. METHODS: MR-RFA was evaluated with simulation of electric and magnetic fields to predict the increase in local specific-absorption-rate (SAR)...
September 18, 2017: IEEE Transactions on Medical Imaging
https://www.readbyqxmd.com/read/28812002/image-guided-thermal-ablation-with-mr-based-thermometry
#8
REVIEW
Mingming Zhu, Ziqi Sun, Chin K Ng
Thermal ablation techniques such as radiofrequency, microwave, high intensity focused ultrasound (HIFU) and laser have been used as minimally invasive strategies for the treatment of variety of cancers. MR thermometry methods are readily available for monitoring thermal distribution and deposition in real time, leading to decrease of incidents of normal tissue damage around targeted lesion. HIFU and laser-induced thermal therapy (LITT) are the two widely accepted tumor ablation techniques because of their compatibility with MR systems...
June 2017: Quantitative Imaging in Medicine and Surgery
https://www.readbyqxmd.com/read/28795419/simultaneous-mr-thermometry-and-acoustic-radiation-force-imaging-using-interleaved-acquisition
#9
Joshua T de Bever, Henrik Odéen, Lorne W Hofstetter, Dennis L Parker
PURPOSE: A novel and practical method for simultaneously performing MR acoustic radiation force imaging (ARFI) and proton resonance frequency (PRF)-shift thermometry has been developed and tested. This could be an important tool for evaluating the success of MR-guided focused ultrasound procedures for which MR-thermometry measures temperature and thermal dose and MR-ARFI detects changes in tissue mechanical properties. METHODS: MR imaging was performed using a gradient recalled echo segmented echo-planar imaging pulse sequence with bipolar motion encoding gradients (MEG)...
August 10, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28748092/a-focused-ultrasound-treatment-system-for-moving-targets-part-i-generic-system-design-and-in-silico-first-stage-evaluation
#10
Michael Schwenke, Jan Strehlow, Daniel Demedts, Sabrina Haase, Diego Barrios Romero, Sven Rothlübbers, Caroline von Dresky, Stephan Zidowitz, Joachim Georgii, Senay Mihcin, Mario Bezzi, Christine Tanner, Giora Sat, Yoav Levy, Jürgen Jenne, Matthias Günther, Andreas Melzer, Tobias Preusser
BACKGROUND: Focused ultrasound (FUS) is entering clinical routine as a treatment option. Currently, no clinically available FUS treatment system features automated respiratory motion compensation. The required quality standards make developing such a system challenging. METHODS: A novel FUS treatment system with motion compensation is described, developed with the goal of clinical use. The system comprises a clinically available MR device and FUS transducer system...
2017: Journal of Therapeutic Ultrasound
https://www.readbyqxmd.com/read/28728442/an-integrated-platform-for-small-animal-hyperthermia-investigations-under-ultra-high-field-mri-guidance
#11
Sergio Curto, Pegah Faridi, Tej B Shrestha, Marla Pyle, Leila Maurmann, Deryl Troyer, Stefan H Bossmann, Punit Prakash
PURPOSE: Integrating small-animal experimental hyperthermia instrumentation with magnetic resonance imaging (MRI) affords real-time monitoring of spatial temperature profiles. This study reports on the development and preliminary in vivo characterisation of a 2.45 GHz microwave hyperthermia system for pre-clinical small animal investigations, integrated within a 14 T ultra-high-field MRI scanner. MATERIALS AND METHODS: The presented system incorporates a 3.5 mm (OD) directional microwave hyperthermia antenna, positioned adjacent to the small-animal target, radiating microwave energy for localised heating of subcutaneous tumours...
July 21, 2017: International Journal of Hyperthermia
https://www.readbyqxmd.com/read/28714565/mri-compatible-breast-rib-phantom-for-evaluating-ultrasonic-thermal-exposures
#12
Georgios Menikou, Marinos Yiannakou, Christos Yiallouras, Cleanthis Ioannides, Christakis Damianou
INTRODUCTION: The target of this study was the development of a magnetic resonance imaging (MRI) compatible breast phantom for focused ultrasound which includes plastic (ABS) ribs. The objective of the current study was the evaluation of a focused ultrasound procedure using the proposed phantom that eliminates rib heating. MATERIAL AND METHODS: The proposed phantom was evaluated using two different focused ultrasound exposures. The surrounding breast tissue was mimicked using an agar-silica-evaporation milk gel (2% w/v - 2% w/v - 40% v/v)...
July 17, 2017: International Journal of Medical Robotics + Computer Assisted Surgery: MRCAS
https://www.readbyqxmd.com/read/28656726/correlation-distance-dependence-of-the-resonance-frequency-of-intermolecular-zero-quantum-coherences-and-its-implication-for-mr-thermometry
#13
Le Zhang, Andrew McCallister, Karl M Koshlap, Rosa Tamara Branca
PURPOSE: Because the resonance frequency of water-fat intermolecular zero-quantum coherences (iZQCs) reflects the water-fat frequency separation at the microscopic scale, these frequencies have been proposed and used as a mean to obtain more accurate temperature information. The purpose of this work was to investigate the dependence of the water-fat iZQC resonance frequency on sample microstructure and on the specific choice of the correlation distance. METHODS: The effect of water-fat susceptibility gradients on the water-methylene iZQC resonance frequency was first computed and then measured for different water-fat emulsions and for a mixture of porcine muscle and fat...
June 27, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28654336/focal-therapy-for-prostate-cancer-with-in-bore-mr-guided-focused-ultrasound-two-year-follow-up-of-a-phase-i-trial-complications-and-functional-outcomes
#14
Kae Jack Tay, Christopher W S Cheng, Weber K O Lau, James Khoo, Choon Hua Thng, Jin Wei Kwek
Purpose To report the safety profile and 2-year functional outcomes of in-bore magnetic resonance (MR)-guided focused ultrasound on single cancer foci in men with prostate cancer. Materials and Methods Ethics approval was obtained from the centralized institutional review board for this prospective single-arm study, and patients provided informed consent. Patients with untreated low-volume low-grade prostate cancer (clinical stage T2a or lower; Gleason score, 3+3; index tumor ≤10 mm(3)) underwent MR-guided focused ultrasound between July 2011 and February 2013...
November 2017: Radiology
https://www.readbyqxmd.com/read/28646608/fluid-filling-of-the-digestive-tract-for-improved-proton-resonance-frequency-shift-based-mr-thermometry-in-the-pancreas
#15
Cyril J Ferrer, Lambertus W Bartels, Marijn van Stralen, Baudouin Denis de Senneville, Chrit T W Moonen, Clemens Bos
PURPOSE: To demonstrate that fluid filling of the digestive tract improves the performance of respiratory motion-compensated proton resonance frequency shift (PRFS)-based magnetic resonance (MR) thermometry in the pancreas. MATERIALS AND METHODS: In seven volunteers (without heating), we evaluated PRFS thermometry in the pancreas with and without filling of the surrounding digestive tract. All data acquisition was performed at 1.5T, then all datasets were analyzed and compared with three different PRFS respiratory motion-compensated thermometry methods: gating, multibaseline, and referenceless...
June 24, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28643383/multiecho-pseudo-golden-angle-stack-of-stars-thermometry-with-high-spatial-and-temporal-resolution-using-k-space-weighted-image-contrast
#16
Bryant T Svedin, Allison Payne, Bradley D Bolster, Dennis L Parker
PURPOSE: Implement and evaluate a 3D MRI method to measure temperature changes with high spatial and temporal resolution and large field of view. METHODS: A multiecho pseudo-golden angle stack-of-stars (SOS) sequence with k-space weighted image contrast (KWIC) reconstruction was implemented to simultaneously measure multiple quantities, including temperature, initial signal magnitude M(0), transverse relaxation time ( T2*), and water/fat images. Respiration artifacts were corrected using self-navigation...
June 22, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28643045/validation-of-a-mathematical-model-for-laser-induced-thermotherapy-in-liver-tissue
#17
F Hübner, C Leithäuser, B Bazrafshan, N Siedow, T J Vogl
The purpose of the study was to develop a simulation approach for laser-induced thermotherapy (LITT) that is based on mathematical models for radiation transport, heat transport, and tissue damage. The LITT ablation was applied to ex vivo pig liver tissue. Experiments were repeated with different laser powers, i.e., 22-34 W, and flow rates of the cooling water in the applicator system, i.e., 47-92 ml/min. During the procedure, the temperature was measured in the liver sample at different distances to the applicator as well as in the cooling circuit using a fiber optic thermometer...
August 2017: Lasers in Medical Science
https://www.readbyqxmd.com/read/28598900/interleaved-mapping-of-temperature-and-longitudinal-relaxation-rate-to-monitor-drug-delivery-during-magnetic-resonance-guided-high-intensity-focused-ultrasound-induced-hyperthermia
#18
Esther Kneepkens, Edwin Heijman, Jochen Keupp, Steffen Weiss, Klaas Nicolay, Holger Grüll
OBJECTIVES: Magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) is a method to heat lesions noninvasively to a stable, elevated temperature and a well-suited method to induce local hyperthermia (41°C-43°C) in deep-seated tissues. Magnetic Resonance (MR) imaging provides therapy planning on anatomical images and offers temperature feedback based on near-real-time MR thermometry. Although constant acquisition of MR thermometry data is crucial to ensure prolonged hyperthermia, it limits the freedom to perform measurements of other MR parameters, which are of interest during hyperthermia treatments...
June 8, 2017: Investigative Radiology
https://www.readbyqxmd.com/read/28595499/thermal-diffusivity-and-perfusion-constants-from-in-vivo-mr-guided-focused-ultrasound-treatments-a-feasibility-study
#19
Christopher R Dillon, Viola Rieke, Pejman Ghanouni, Allison Payne
PURPOSE: This study investigates the feasibility of non-invasively determining thermal diffusivity (α) and the Pennes perfusion parameter (w) from preclinical and clinical magnetic resonance-guided focused ultrasound (MRgFUS) temperature data. MATERIALS AND METHODS: Pre-clinical MRgFUS experiments were performed in rabbit muscle (N = 3, 28 sonications) using three-dimensional MR thermometry. 8 sonications were made in a clinical QA phantom with two-dimensional thermometry...
June 8, 2017: International Journal of Hyperthermia
https://www.readbyqxmd.com/read/28590938/combined-passive-acoustic-mapping-and-magnetic-resonance-thermometry-for-monitoring-phase-shift-nanoemulsion-enhanced-focused-ultrasound-therapy
#20
Calum Crake, F Can Meral, Mark T Burgess, Iason T Papademetriou, Nathan J McDannold, Tyrone M Porter
Focused ultrasound (FUS) has the potential to enable precise, image-guided noninvasive surgery for the treatment of cancer in which tumors are identified and destroyed in a single integrated procedure. However, success of the method in highly vascular organs has been limited due to heat losses to perfusion, requiring development of techniques to locally enhance energy absorption and heating. In addition, FUS procedures are conventionally monitored using MRI, which provides excellent anatomical images and can map temperature, but is not capable of capturing the full gamut of available data such as the acoustic emissions generated during this inherently acoustically-driven procedure...
July 13, 2017: Physics in Medicine and Biology
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