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10 results on '"Isabelle Saniour"'

1. Characterization of a Low-Profile, Flexible, and Acoustically Transparent Receive-Only MRI Coil Array for High Sensitivity MR-Guided Focused Ultrasound

Author

Isabelle Saniour, Fraser J. L. Robb, Victor Taracila, Vishwas Mishra, Jana Vincent, Henning U. Voss, Michael G. Kaplitt, J. Levi Chazen, and Simone Angela Winkler

Subjects
Magnetic resonance imaging, coils, ultrasonic transducer arrays, Electrical engineering. Electronics. Nuclear engineering, TK1-9971
Abstract

Magnetic resonance guided focused ultrasound (MRgFUS) is a non-invasive therapeutic modality for neurodegenerative diseases that employs real-time imaging and thermometry monitoring of targeted regions. MRI is used in guidance of ultrasound treatment; however, the MR image quality in current clinical applications is poor when using the vendor built-in body coil. We present an 8-channel, ultra-thin, flexible, and acoustically transparent receive-only head coil design (FUS-Flex) to improve the signal-to-noise ratio (SNR) and thus the quality of MR images during MRgFUS procedures. Acoustic simulations/experiments exhibit transparency of the FUS-Flex coil as high as 97% at 650 kHz. Electromagnetic simulations show a SNR increase of $13\times $ over the body coil. In vivo results show an increase of the SNR over the body coil by a factor of 7.3 with $2\times $ acceleration (equivalent to $11\times $ without acceleration) in the brain of a healthy volunteer, which agrees well with simulation. These preliminary results show that the use of a FUS-Flex coil in MRgFUS surgery can increase MR image quality, which could yield improved focal precision, real-time intraprocedural anatomical imaging, and real-time 3D thermometry mapping.

Published
2022
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2. Versatile cryogen-free cryostat for the electromagnetic characterization of superconducting radiofrequency coils

Author

Isabelle Saniour, Michel Geahel, Javier Briatico, Cornelis J. van der Beek, Georges Willoquet, Laurène Jourdain, Bertrand Baudouy, Gilles Authelet, Jean-Christophe Ginefri, Luc Darrasse, and Marie Poirier-Quinot

Subjects
Superconductivity, HTS coil, Cryostat, High sensitivity, Physics, QC1-999, Optics. Light, QC350-467, Descriptive and experimental mechanics, QC120-168.85
Abstract

Abstract The use of high temperature superconducting (HTS) radio frequency (RF) coils in Magnetic Resonance Imaging (MRI) greatly improves the signal-to-noise ratio (SNR) in many biomedical applications and particularly in micro-MRI. However, a detailed understanding of the electrical behavior of HTS coils is important in order to optimize their performance through MR experiments. This paper presents a simple and versatile cryogen-free cryostat designed to characterize the RF properties of HTS coils prior to their use in MRI. The cryostat can be used at temperatures from 50 K to 300 K, with a control precision of approximately 3 mK at 70 K, and can measure the RF electrical power transmitted to an HTS coil over a range from 1 μW to 10 W. The quality factor and resonance frequency of the tested HTS coil are determined as a function of the temperature and the power it dissipates. This cryostat also permits the dynamic adjustment of the coil resonance frequency via temperature control. Finally, this study demonstrates that the HTS coil takes less than 12 μs to transit from the superconducting to the dissipative state, which is compatible with MRI requirements.

Published
2020
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3. Serial and Parallel Active Decoupling Characterization Using RF MEMS Switches for Receiver Endoluminal Coils at 1.5 T

Author

Isabelle Saniour, Fraser Robb, Olivier Beuf, Simon A. Lambert, Kevin Tse Ve Koon, Hamza Raki, Henri Souchay, Beuf, Olivier, RMN et optique : De la mesure au biomarqueur, Centre de Recherche en Acquisition et Traitement de l'Image pour la Santé (CREATIS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Hospices Civils de Lyon (HCL)-Université Jean Monnet - Saint-Étienne (UJM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Hospices Civils de Lyon (HCL)-Université Jean Monnet - Saint-Étienne (UJM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), General Electric Medical Systems [Buc] (GE Healthcare), General Electric Medical Systems, GE Healthcare, MRI coils division, GE Healthcare (GEHC), Université Jean Monnet [Saint-Étienne] (UJM)-Hospices Civils de Lyon (HCL)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Jean Monnet [Saint-Étienne] (UJM)-Hospices Civils de Lyon (HCL)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), and Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)

Subjects
Scanner, [SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging, Active decoupling, MR switch, Topology, 01 natural sciences, Optical switch, endoluminal coils, law.invention, law, Electrical and Electronic Engineering, Instrumentation, ComputingMilieux_MISCELLANEOUS, Microelectromechanical systems, Physics, 010401 analytical chemistry, Colon wall, PIN diode, [SPI.TRON] Engineering Sciences [physics]/Electronics, [SPI.TRON]Engineering Sciences [physics]/Electronics, 0104 chemical sciences, Mechanical system, MEMS, [SDV.IB.IMA] Life Sciences [q-bio]/Bioengineering/Imaging, Radio frequency, Decoupling (electronics)
Abstract

MEMS (Micro Electro Mechanical System) switches were assessed and compared to PIN diode in fulfilling the task of active decoupling of Receiver Endoluminal Coils (RECs). Three prototype RECs with the PIN diode in parallel ( ${p}$ PIN), MEMS in parallel ( ${p}$ MEMS) and MEMS in series ( ${s}$ MEMS) with the REC loop were built. Quality factors (Q-values), decoupling efficiency and switching delays were characterized on bench and Signal-to-Noise Ratios (SNRs) established on images at 1.5 T. Q-values were equal to 62.5, 41.2 and 65.1 for ${p}$ PIN, ${s}$ MEMS and ${p}$ MEMS, respectively. In the decoupled state, reflection coefficients S11 and S21 at resonance frequency both indicated proper decoupling. Switching delays were less than $0.7~\mu \text{s}$ and $10~\mu \text{s}$ for ${p}$ PIN and MEMS RECs, respectively. Decoupling/coupling delays of MEMS remained compatible with most Magnetic Resonance (MR) clinical applications. For all prototypes, MR images displayed no signal saturation and similar elliptical image sensitivity patterns. No artifacts due to active decoupling failure were observed. Mean SNR values obtained with ${p}$ MEMS REC were higher than those obtained with ${s}$ MEMS REC but lower than with ${p}$ PIN REC because of the use of additional instrumentation to render the scanner compatible with the MEMS utilization. MEMS in parallel are an interesting alternative to PIN diode for decoupling and could lead to better SNR with a compatible MR system (dedicated control signal). The MEMS in series can be used for both decoupling and reconfiguration of the REC loop geometry for colon wall examination.

Published
2020

4. MRSaiFE: Tissue Heating Prediction for MRI: a Feasibility Study

Author

J. Thomas Vaughan, Fraser Robb, Akshay S. Chaudhari, Simone A. Winkler, and Isabelle Saniour

Subjects
medicine.diagnostic_test, Mean squared error, business.industry, Computer science, Specific absorption rate, Magnetic resonance imaging, Residual, Software, Ultra high frequency, Proof of concept, medicine, Radio frequency, business, Algorithm
Abstract

A to-date unsolved and highly limiting safety concern for Ultra High-Field (UHF) magnetic resonance imaging (MRI) is the deposition of radiofrequency (RF) power in the body, quantified by the specific absorption rate (SAR), leading to dangerous tissue heating/damage in the form of local SAR hotspots that cannot currently be measured/monitored, thereby severely limiting the applicability of the technology for clinical practice and in regulatory approval. The goal of this study has been to show proof of concept of an artificial intelligence (AI) based exam-integrated real-time MRI safety prediction software (MRSaiFE) facilitating the safe generation of 3T and 7T images by means of accurate local SAR-monitoring at sub-W/kg levels. We trained the software with a small database of image as a feasibility study and achieved successful proof of concept for both field strengths. SAR patterns were predicted with a residual root mean squared error (RSME) of along with a structural similarity (SSIM) level of > 84{\%}$ for both field strengths (3T and 7T).

Published
2020

5. Versatile cryogen-free cryostat for the electromagnetic characterization of superconducting radiofrequency coils

Author

Laurène Jourdain, Michel Geahel, J. Briatico, Gilles Authelet, Jean-Christophe Ginefri, Bertrand Baudouy, Cornelis J. van der Beek, Georges Willoquet, Isabelle Saniour, Luc Darrasse, Marie Poirier-Quinot, Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), Centre National de la Recherche Scientifique (CNRS)-THALES, and THALES-Centre National de la Recherche Scientifique (CNRS)

Subjects
Cryostat, Superconductivity, Materials science, Physics::Medical Physics, 01 natural sciences, 030218 nuclear medicine & medical imaging, 03 medical and health sciences, 0302 clinical medicine, Quality (physics), Condensed Matter::Superconductivity, 0103 physical sciences, lcsh:QC350-467, Instrumentation, lcsh:QC120-168.85, 010302 applied physics, High sensitivity, Temperature control, business.industry, lcsh:QC1-999, Power (physics), [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], Electromagnetic coil, HTS coil, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Optoelectronics, lcsh:Descriptive and experimental mechanics, Radio frequency, [PHYS.COND.CM-SCE]Physics [physics]/Condensed Matter [cond-mat]/Strongly Correlated Electrons [cond-mat.str-el], business, lcsh:Physics, lcsh:Optics. Light, Radiofrequency coil
Abstract

The use of high temperature superconducting (HTS) radio frequency (RF) coils in Magnetic Resonance Imaging (MRI) greatly improves the signal-to-noise ratio (SNR) in many biomedical applications and particularly in micro-MRI. However, a detailed understanding of the electrical behavior of HTS coils is important in order to optimize their performance through MR experiments. This paper presents a simple and versatile cryogen-free cryostat designed to characterize the RF properties of HTS coils prior to their use in MRI. The cryostat can be used at temperatures from 50 K to 300 K, with a control precision of approximately 3 mK at 70 K, and can measure the RF electrical power transmitted to an HTS coil over a range from 1 μW to 10 W. The quality factor and resonance frequency of the tested HTS coil are determined as a function of the temperature and the power it dissipates. This cryostat also permits the dynamic adjustment of the coil resonance frequency via temperature control. Finally, this study demonstrates that the HTS coil takes less than 12 μs to transit from the superconducting to the dissipative state, which is compatible with MRI requirements.

Published
2020

6. A temperature-controlled cryogen free cryostat integrated with transceiver-mode superconducting coil for high-resolution magnetic resonance imaging

Author

Rose-Marie Dubuisson, Georges Willoquet, Luc Darrasse, Jean-Christophe Ginefri, Isabelle Saniour, Marie Poirier-Quinot, Laurène Jourdain, Gilles Authelet, Bertrand Baudouy, Laboratoire d’imagerie biomédicale multimodale [Orsay] (BioMaps), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), LaBoratoire d'Imagerie biOmédicale MultimodAle Paris-Saclay (BIOMAPS), Service Hospitalier Frédéric Joliot (SHFJ), Université Paris-Saclay-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010302 applied physics, Cryostat, Temperature control, Materials science, business.industry, [SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging, Resonance, Liquid nitrogen, 01 natural sciences, Imaging phantom, 010305 fluids & plasmas, Electromagnetic coil, 0103 physical sciences, Optoelectronics, business, Pulse tube refrigerator, Instrumentation, Radiofrequency coil
Abstract

International audience; Small-sized High Temperature Superconducting (HTS) radiofrequency coils are used in a number of micro-magnetic resonance imaging applications and demonstrate a high detection sensitivity that improves the signal-to-noise ratio. However, the use of HTS coils could be limited by the rarity of cryostats that are suitable for the MR environment. This study presents a magnetic resonance (MR)-compatible and easily operated cryogen-free cryostat based on the pulse tube cryocooler technology for the cooling and monitoring of HTS coils below the temperature of liquid nitrogen. This cryostat features a real-time temperature control function that allows the precise frequency adjustment of the HTS coil. The influence of the temperature on the electrical properties, resonance frequency (f0), and quality factor (Q) of the HTS coil was investigated. Temperature control is obtained with an accuracy of over 0.55 K from 60 K to 86 K, and the sensitivity of the system, extracted from the frequency measurement from 60 K to 75 K, is of about 2 kHz/K, allowing a fine retuning (within few Hz, compared to 10 kHz bandwidth) in good agreement with experimental requirements. We demonstrated that the cryostat, which is mainly composed of non-magnetic materials, does not perturb the electromagnetic field in any way. MR images of a 10 × 10 × 15 mm3 liquid phantom were acquired using the HTS coil as a transceiver with a spatial resolution of 100 × 100 × 300 µm3 in less than 20 min under experimental conditions at 1.5 T.

Published
2020

7. Feasibility and characterization of a safe susceptibility‐matched endorectal coil for MR spectroscopy

Author

Cécile Rabrait-Lerman, Isabelle Saniour, Olivier Beuf, Jean-Marie Verret, Frank Pilleul, Beuf, Olivier, RMN et optique : De la mesure au biomarqueur, Centre de Recherche en Acquisition et Traitement de l'Image pour la Santé (CREATIS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Hospices Civils de Lyon (HCL)-Université Jean Monnet - Saint-Étienne (UJM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Hospices Civils de Lyon (HCL)-Université Jean Monnet - Saint-Étienne (UJM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), General Electric Medical Systems [Buc] (GE Healthcare), General Electric Medical Systems, Université Jean Monnet [Saint-Étienne] (UJM)-Hospices Civils de Lyon (HCL)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Jean Monnet [Saint-Étienne] (UJM)-Hospices Civils de Lyon (HCL)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), and Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)

Subjects
In vivo magnetic resonance spectroscopy, Scanner, Magnetic Resonance Spectroscopy, Materials science, Radio Waves, [SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging, Signal-To-Noise Ratio, Imaging phantom, 030218 nuclear medicine & medical imaging, 03 medical and health sciences, 0302 clinical medicine, Nuclear magnetic resonance, Dielectric heating, medicine, Humans, Radiology, Nuclear Medicine and imaging, Spectroscopy, ComputingMilieux_MISCELLANEOUS, [SPI.SIGNAL] Engineering Sciences [physics]/Signal and Image processing, medicine.diagnostic_test, Phantoms, Imaging, Rectum, Magnetic resonance imaging, [SPI.TRON] Engineering Sciences [physics]/Electronics, [SPI.TRON]Engineering Sciences [physics]/Electronics, Full width at half maximum, [SDV.IB.IMA] Life Sciences [q-bio]/Bioengineering/Imaging, Electromagnetic coil, Feasibility Studies, Molecular Medicine, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing, 030217 neurology & neurosurgery, Endorectal coil
Abstract

When using endorectal coils, local radiofrequency (RF) heating may occur in the surrounding tissue. Furthermore, most endorectal coils create a susceptibility artifact detrimental to both anatomical magnetic resonance imaging (MRI) and spectroscopy (MRS) acquisitions. We aimed at assessing the safety and MRS performance of a susceptibility-matched endorectal coil for further rectal wall analysis. Experiments were performed on a General Electric MR750 3 T scanner. A variable number of miniaturized passive RF traps were incorporated in the reception cable. The assessment of RF heating and coil sensitivity was conducted on a 1.5% agar-agar phantom doped with NaCl. Several susceptibility-matched materials such as Ultem, perfluorocarbon and barium sulfate were then compared with an external coil. Finally, Ultem was used as a solid support for an endorectal coil and compared with a reference coil. Phantom experiments exhibited a complete suppression of both the RF heating phenomenon and the coil sensitivity artifact. Ultem was the material that produced the smallest image distortion. The full width at half maximum of MR spectra acquired using the susceptibility-matched endorectal coil showed at least 30% narrowing compared with a reference endorectal coil. A susceptibility-matched endorectal coil with RF traps incorporated was validated on phantoms. This coil appears to be a promising device for future in vivo experiments.

Published
2020

8. Electro-optic probe for real-time assessments of RF electric field produced in an MRI scanner: Feasibility tests at 3 and 4.7 T

Author

Anne-Laure Perrier, Raphaël Sablong, Isabelle Saniour, Lionel Duvillaret, Gwenaël Gaborit, Olivier Beuf, Laurane Gillette, Guillaume Revillod, RMN et optique : De la mesure au biomarqueur, Centre de Recherche en Acquisition et Traitement de l'Image pour la Santé (CREATIS), Université Jean Monnet [Saint-Étienne] (UJM)-Hospices Civils de Lyon (HCL)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Jean Monnet [Saint-Étienne] (UJM)-Hospices Civils de Lyon (HCL)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM), Institut de Microélectronique, Electromagnétisme et Photonique - Laboratoire d'Hyperfréquences et Caractérisation (IMEP-LAHC ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Kapteos SAS, Centre de Recherche en Acquisition et Traitement de l'Image pour la Santé ( CREATIS ), Hospices Civils de Lyon ( HCL ) -Université Jean Monnet [Saint-Étienne] ( UJM ) -Institut National de la Santé et de la Recherche Médicale ( INSERM ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Claude Bernard Lyon 1 ( UCBL ), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon ( INSA Lyon ), Université de Lyon-Institut National des Sciences Appliquées ( INSA ) -Institut National des Sciences Appliquées ( INSA ), Institut de Microélectronique, Electromagnétisme et Photonique - Laboratoire d'Hyperfréquences et Caractérisation ( IMEP-LAHC ), Centre National de la Recherche Scientifique ( CNRS ) -Université Savoie Mont Blanc ( USMB [Université de Savoie] [Université de Chambéry] ) -Institut National Polytechnique de Grenoble ( INPG ) -Université Joseph Fourier - Grenoble 1 ( UJF ) -Institut polytechnique de Grenoble - Grenoble Institute of Technology ( Grenoble INP ) -Université Grenoble Alpes ( UGA ), 5 - RMN et optique : De la mesure aux biomarqueurs, and Université de Lyon-Institut National des Sciences Appliquées ( INSA ) -Institut National des Sciences Appliquées ( INSA ) -Hospices Civils de Lyon ( HCL ) -Université Jean Monnet [Saint-Étienne] ( UJM ) -Institut National de la Santé et de la Recherche Médicale ( INSERM ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Claude Bernard Lyon 1 ( UCBL )

Subjects
Scanner, Materials science, Optical Phenomena, Radio Waves, [SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging, Physics::Medical Physics, 02 engineering and technology, Dielectric, Signal-To-Noise Ratio, 030218 nuclear medicine & medical imaging, 03 medical and health sciences, 0302 clinical medicine, Nuclear magnetic resonance, Optics, Electricity, Electric field, 0202 electrical engineering, electronic engineering, information engineering, Humans, Radiology, Nuclear Medicine and imaging, Spectroscopy, [ SDV.IB.IMA ] Life Sciences [q-bio]/Bioengineering/Imaging, ComputingMilieux_MISCELLANEOUS, business.industry, Specific absorption rate, 020206 networking & telecommunications, Magnetostatics, Magnetic Resonance Imaging, Pockels effect, Magnetic field, Magnetic Fields, Electromagnetic coil, Molecular Medicine, Feasibility Studies, business, Crystallization
Abstract

International audience; During magnetic resonance imaging (MRI) examinations, the average specific absorption rate (SAR) of the whole body is calculated as an index of global energy deposition in biological tissue without taking into account the presence of metallic implants or conductive materials. However, this global SAR calculation is not sufficient to ensure patient safety and a local SAR measurement should be carried out. Several measurement techniques have already been used to evaluate the local SAR, in particular electric field (E-field) probes, but the accuracy of the measurements and the resolutions (spatial and temporal) depend strongly on the measurement method/probe. This work presents an MR-compatible, subcentimeter probe based on an electro-optic (EO) principle enabling a real-time measurement of the local E-field during MRI scans. The experiments using these probes were performed on two different MR systems (preclinical and clinical) having different static magnetic field strengths and with different volume coil geometries. The E-field was measured with unloaded (in air) and loaded volume coils in order to assess the sensing characteristics of the optical probe. The results show an excellent linearity between the measured E-field and the radiofrequency (RF) magnetic field in both experimental conditions. Moreover, the distribution of the E-field throughout the volume coil was experimentally determined and was in good agreement with numerical simulations. Finally, we demonstrate through our measurements that the E-field depends strongly on the dielectric properties of the medium.

Published
2018

9. Active Optical-Based Detuning Circuit For Receiver Endoluminal Coil

Author

Anne-Laure Perrier, Gwenaël Gaborit, Isabelle Saniour, R Aydé, Olivier Beuf, Raphaël Sablong, Lionel Duvillaret, 5 - RMN et optique : De la mesure aux biomarqueurs, Centre de Recherche en Acquisition et Traitement de l'Image pour la Santé ( CREATIS ), Université Claude Bernard Lyon 1 ( UCBL ), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon ( INSA Lyon ), Université de Lyon-Institut National des Sciences Appliquées ( INSA ) -Institut National des Sciences Appliquées ( INSA ) -Hospices Civils de Lyon ( HCL ) -Université Jean Monnet [Saint-Étienne] ( UJM ) -Institut National de la Santé et de la Recherche Médicale ( INSERM ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Claude Bernard Lyon 1 ( UCBL ), Université de Lyon-Institut National des Sciences Appliquées ( INSA ) -Institut National des Sciences Appliquées ( INSA ) -Hospices Civils de Lyon ( HCL ) -Université Jean Monnet [Saint-Étienne] ( UJM ) -Institut National de la Santé et de la Recherche Médicale ( INSERM ) -Centre National de la Recherche Scientifique ( CNRS ), Institut de Microélectronique, Electromagnétisme et Photonique - Laboratoire d'Hyperfréquences et Caractérisation ( IMEP-LAHC ), Université Joseph Fourier - Grenoble 1 ( UJF ) -Institut polytechnique de Grenoble - Grenoble Institute of Technology ( Grenoble INP ) -Institut National Polytechnique de Grenoble ( INPG ) -Université Savoie Mont Blanc ( USMB [Université de Savoie] [Université de Chambéry] ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes ( UGA ), Kapteos SAS, RMN et optique : De la mesure au biomarqueur, Centre de Recherche en Acquisition et Traitement de l'Image pour la Santé (CREATIS), Université Jean Monnet [Saint-Étienne] (UJM)-Hospices Civils de Lyon (HCL)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Jean Monnet [Saint-Étienne] (UJM)-Hospices Civils de Lyon (HCL)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM), Institut de Microélectronique, Electromagnétisme et Photonique - Laboratoire d'Hyperfréquences et Caractérisation (IMEP-LAHC ), and Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])

Subjects
Materials science, [SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging, Physics::Medical Physics, Phase (waves), 030218 nuclear medicine & medical imaging, law.invention, 03 medical and health sciences, 0302 clinical medicine, Optics, photodiodes, law, magnetic resonance imaging, Physics::Atomic Physics, General Nursing, [ SDV.IB.IMA ] Life Sciences [q-bio]/Bioengineering/Imaging, Electronic circuit, Quantitative Biology::Biomolecules, fibered sensor, business.industry, PIN diode, Photodiode, optical detuning, Coil noise, Electromagnetic coil, galvanic link, Physics::Accelerator Physics, Transceiver, Telecommunications, business, endoluminal coil, 030217 neurology & neurosurgery, Coil tap
Abstract

International audience; In this paper we demonstrate the effectiveness of an active optical detuning circuit for magnetic resonance imaging endoluminal receiver coil. Three endoluminal coils prototypes were built: a coil without any detuning circuit, a coil with a galvanic (classic) detuning circuit using a PIN diode, and a coil with an optical detuning circuit using two photodiodes in parallel with a PIN diode. These coils were built and characterized on a laboratory experimental bench. Then, an in vitro experiment was performed with a 3.0 T MR system to evaluate the impact of the endoluminal receiver coils in detuned phase on the image uniformity distribution measured using the body coil. Next, the endoluminal coil was used as a receiver coil to compare the signal-to-noise ratio (SNR) distribution based on iso-contour maps. On experimental bench, the results show an increase delay of the switching times (tuned-detuned or detuned-tuned) for optical-detuned coils of about 10 μs due to the electro-optical circuits, delay still compatible with requirements. When the body coil is used as a transceiver, the SNR uniformity is similar whether the galvanic or the optical detuning circuit is used. Finally, the SNR iso-contours of the different endoluminal coils prototypes are comparable.

Published
2017
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10. All polymer cryogen free cryostat for μ-MRI application at clinical field

Author

Bertrand Baudouy, A. Bonelli, Jean-Christophe Ginefri, Gilles Authelet, Isabelle Saniour, and Marie Poirier-Quinot

Subjects
010302 applied physics, Cryostat, Superconductivity, Scanner, Materials science, medicine.diagnostic_test, Physics::Instrumentation and Detectors, business.industry, Physics::Medical Physics, Magnetic resonance imaging, 01 natural sciences, Optics, Magnet, 0103 physical sciences, medicine, Physics::Accelerator Physics, Sensitivity (control systems), Radio frequency, 010306 general physics, business, Image resolution
Abstract

To improve the detection sensitivity of Micro Magnetic Resonance Imaging (μ-MRI) in humans, small animals or biological sample, it is necessary to reach higher spatial resolution. Radio Frequency (RF) YBaCuO film coils, in superconducting state, are used for that purpose, instead of copper coils. In working condition, these miniature RF coils are located in clinical MRI scanners (few Tesla) and very closed to the biological sample under investigation. A non magnetic cryostat has been designed and constructed to operate these RF coils in this particular medical environment. This cryostat is principally made of polymer materials to reduce the electromagnetic perturbations to the MRI magnet and the cryogenic scheme has been chosen to be cryogen free. In this paper, we describe the cryostat and present the experimental thermal characterizations and the first images obtained in a clinical MRI scanner.

Published
2019

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