| Computer # |
| 1593.
 | 33 | A Wireless Receive Surface Coil at 1.5T Busra Kahraman-Agir1, Rawish Roshan Bansropansingh1, Mark Gosselink1, and Dennis Klomp1
1Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands Keywords: Non-Array RF Coils, Antennas & Waveguides, Non-Array RF Coils, Antennas & Waveguides, wireless coils, inductive coupling Motivation: MRI is a highly preferable but also an expensive modality mainly due to 1)high operational cost, 2)staff cost, 3)long scan and preparation times. Goal(s): Reducing costs and simplifying MRI scans. Approach: A wired coil and a wireless coil which was inductively coupled to a receiver loop were compared in terms of their efficiency and SNR results. Results: On the bench, a 0.8 dB+/-0.5dB of decrease was observed in the efficiency of the wireless coil over a range of 3 cm. The SNR of the wireless coil was practically identical to the wired coil both in phantom and in vivo MR images. Impact: The efficiency
obtained by a wired coil decreased by 0.8 dB when an inductively coupled
wireless coil was used. Phantom and in vivo measurements
show a practically identical sensitivity profile and SNR for both coils. |
| 1594.
 | 34 | A low-cost setup for orientation-dependent post-mortem MRI under temperature control Niklas Wallstein1, Roland Müller1, André Pampel1, and Harald E. Möller1,2
1NMR Methods & Development Group, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, 2Felix Bloch Institute for Solid State Physics, Leipzig University, Leipzig, Germany Keywords: New Devices, New Devices, Orientation-dependent MRI, Post-mortem MRI, Temperature control, Temperature-dependent MRI, Tiltable Coil Motivation: Systematic variation of external parameters can provide insight into whether theoretical models appropriately describe MRI contrast. Goal(s): Our goal was to develop a cost-effective setup for comprehensive temperature- and orientation-dependent relaxation and magnetization-transfer experiments in post-mortem tissue on a clinical scanner. Approach: A remotely tiltable Helmholtz coil was integrated into a thermally insulated box, where the temperature can be adjusted by a heated airflow. Results: Robust coil performance, accurate adjustment of the sample orientation relative to B0 (±1°), and stable temperature conditions (±0.5 °C) were achieved. Theoretically expected temperature dependencies of T1 and diffusivity in agarose were experimentally reproduced. Impact: Well-defined variations of the temperature (between ambient temperature and 45 °C) and sample orientation (between 0 and 90° relative to B0) in MRI experiments with small post-mortem tissue specimens were achieved on a clinical scanner with a cost-effective setup. |
| 1595.
 | 35 | Magnetically Coupled Resonant Wireless RF Coil for MRI Zhiguang Mo1,2, Jiafu Wei1,2, Qiaoyan Chen1,2, Chao Luo1,2, Sen Jia1,2, Bing Wu3, Xiaoliang Zhang4, and Ye Li1,2
1Chinese Academy of Sciences, Shenzhen Institute of Advanced Technology, Shenzhen, China, 2Key Laboratory for Magnetic Resonance and Multimodality Imaging of Guangdong Province, Shenzhen, China, 3Shanghai United Imaging Healthcare Co., Ltd, Shanghai, China, 4Department of Biomedical Engineering, State University of New York, Buffalo, Armenia Keywords: New Devices, Brain, wireless coil Motivation: The bulky cables of the MRI RF coil not only complicate the coil replacement procedure but also lead to a waste of examination time. Goal(s): In order to achieve a lightweight and user-friendly wireless RF coil with high-resolution imaging capability. Approach: In this study, we made a wireless coil and compared its SNR and high-resolution imaging performance with the rat coil RAC and the knee coil alone, using the knee coil as the pickup coil. Results: The wireless coil achieved high-resolution imaging of up to 0.13 mm × 0.13 mm × 1mm on the 3T system. Impact: The experiment demonstrated the potential of wireless RF coils for high-resolution imaging. |
| 1596.
 | 36 | Multimodal surface coils for small animal MR imaging at ultrahigh fields Yunkun Zhao1, Aditya Ashok Bhosale1, and Xiaoliang Zhang1,2
1Department of Biomedical Engineering, State University of New York at Buffalo, Buffalo, NY, United States, 2Department of Electrical Engineering, State University of New York at Buffalo, Buffalo, NY, United States Keywords: Non-Array RF Coils, Antennas & Waveguides, Non-Array RF Coils, Antennas & Waveguides Motivation: High performance RF coils are needed for better SNR so that higher resolution and spectral dispersion can be obtained in small animal MR imaging.
Goal(s): To develop a surface coil with improved SNR over the conventional surface coil for small animal imaging at 7T.
Approach: A small animal surface coil is designed based on multimodal surface coil technique. The coil is investigated and compared with conventional surface coil using full-wave electromagnetic simulations.
Results: The multimodal surface coil shows superior B1 field efficiency and lower E field over standard coils, indicating a potential to gain SNR and resolution. Impact: The proposed multimodal
surface coil can operate at high frequency and provides improved SNR over
conventional surface coils at 7T, opening avenues for highly efficient coil
design in small animal imaging, ultimately enabling the detection of previously indiscernible physiological details.
|
| 1597.
 | 37 | Reed Relay-Switched Tuning Circuit for Stretchable RF Coils in Low Field, Portable MRI Alexandra Nwigwe1, Monika Sliwiak2, Don Straney3, Aaron Purchase2, Lawrence L Wald2,4,5, Jason P Stockmann2,4, and Clarissa Zimmerman Cooley2,4
1Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States, 2Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, United States, 3Independent Consultant, Charlestown, MA, United States, 4Harvard Medical School, Boston, MA, United States, 5Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA, United States Keywords: Non-Array RF Coils, Antennas & Waveguides, Non-Array RF Coils, Antennas & Waveguides, flexible coil Motivation: Portable low-field MRI opens doors for low-cost and point-of-care imaging, but comes at the expense of decreased SNR, resulting in inferior image quality.
Goal(s): We aim to increase SNR with stretchable, subject-adaptable, helmet coils for low-field, portable MRI brain imaging. Specifically, a single-channel Tx/Rx volume coil for brain imaging at 72 mT.
Approach: We use a flexible 3D printed former and elastic bands for stretchable coil former. To account for the coil’s variable inductance, we develop an MATLAB-controlled autotuning circuit, composed of 8 capacitor values that can be switched in/out via Reed relays.
Results: We present a preliminary coil and autotuning system design.
Impact: To unlock portable MRI's full potential, we must boost SNR without sacrificing portability or safety. Our solution involves stretchable RF coil caps that mold to the subject's head in conjunction with an auto-tuning system for optimal performance. |
| 1598.
 | 38 | Design of a Cryogenic RF Coil Prototype for a Full Body 1.5T MRI Receive Array Vitaliy Zhurbenko1, Mark Gosselink2, Ingmar Voogt3, Cezar Alborahal2, Hans Hoogduin2, Rasmus Alexander Jepsen1, Juan Diego Sanchez Heredia1, and Dennis Klomp2
1Technical University of Denmark, Kgs. Lyngby, Denmark, 2University Medical Center Utrecht, Utrecht, Netherlands, 3WaveTronica B.V., Utrecht, Netherlands Keywords: New Devices, New Devices, Cryogenic coils; cryogenic preamplifiers; remote coils Motivation: The MRI scanning procedure often relies on close-fitting RF coils to maximize signal-to-noise (SNR) ratio and assure image quality. Such an approach impairs patient comfort and requires qualified personnel, which increases the overall costs. Goal(s): This study aims to avoid using close-fitting RF coils by integrating them in the bore of the scanner. Approach: The coil is evaluated by developing a single element cryogenic coil prototype for a wide-bore 1.5T MRI system and with simulation to evaluate SNR and decoupling. Results: Simulations indicate that the coil can achieve 15dB of preamplifier decoupling and that cooling results in a 3dB SNR improvement. Impact: Avoiding close proximity
and making RF coils invisible to a patient by integrating them into a bore of an
MRI scanner will positively impact operating costs. While the signal strength is
reduced, SNR can be partially regained by cryogenic cooling. |
| 1599.
 | 39 | A Novel Transceive 2-channel Orthogonally Arranged Dual Loop Solenoid RF Coil Design for Improving Low Field MRI SNR Yan Gu1, Hong Hua Pei2, Xin Qi2, Ren Jie Zong2, Jian Bao2, Shao Ying Huang3, and Bing Keong Li2
1The First People’s Hospital of Lianyungang, Jiangsu Province, Lianyungang, China, 2Jiangsu LiCi Medical Device Co. Ltd, Lianyungang, China, 3Singapore University of Technology and Design, Singapore, Singapore Keywords: Low-Field MRI, Low-Field MRI Motivation: There are growing interest in low field specialised MRI R&D but they are currently burdened by their low SNR images. Goal(s): A novel 2-channel orthogonally arranged dual loop solenoid RF coil design has been proposed to improve low field MR image SNR. Approach: Two transceive 2-Channel RF coil prototypes using the novel design and using conventional design were constructed and tested in a 0.35T MRI system. Results: In comparing the acquired MR images, it is shown that the proposed novel design can improve low field MR image SNR by ≥20% as compared to the conventional design. Impact: A novel 2-channel orthogonally arranged dual loop
solenoid transceive RF coil has been constructed and tested in a 0.35T MRI system. Using this
new RF coil design it is shown that the acquired image SNR can be increased by ≥20%. |
| 1600.
 | 40 | FPGA Microwave Link Testbed for Wireless MRI Ege Turan1, Fraser Robb2, Shreyas Vasanawala3, John Pauly1, and Greig Cameron Scott1
1Electrical Engineering, Stanford University, Stanford, CA, United States, 2GE Healthcare, Aurora, OH, United States, 3Radiology, Stanford University, Stanford, CA, United States Keywords: Hybrid & Novel Systems Technology, Hybrid & Novel Systems Technology, Wireless Motivation: MRI coil arrays are now burdened by cable and connector limitations that inhibit conformability. Goal(s): We seek a low cost approach to wireless MRI coil data links that is easy to scale with multiple array subsections. We demonstrate feasibility of a FPGA-based short-range microwave wireless serial link. Approach: A complete end to end link was constructed for link distances of 20cm. A low power FPGA sent scrambled serial data with embedded start/stop bits to a receiver with FPGA recovery of the data. Results: This complete demo could achieve over 200Mbps with a simple FPGA, mixer and oscillator. Impact: Cutting the cord of MRI arrays has been a long-term goal of MRI engineering. It would eliminate the mechanical and RF pitfalls of the cable, and enable more conformable and wearable receive arrays. |
| 1601.
 | 41 | Simulating the Magnetic Field of a Nonlinear and Time-Varying Arbitrary-Nucleus Coil Charlie Parker Reeder1, Victor Han1, and Chunlei Liu1
1University of California, Berkeley, Berkeley, CA, United States Keywords: In Silico, Simulations, X-Nuclei, RF, Coil, FDTD Motivation: An untuned, non-resonant coil called the ADAPT Coil has recently been developed to excite any nucleus in high field, human-scale MRI. However, the coil’s nonlinear and time-varying characteristics render conventional simulation methods insufficient. Goal(s): To develop an accurate simulation method for nonlinear and time-varying coils. Approach: A finite-difference time-domain solver and a harmonic balance simulator were combined to simulate the linear components and the nonlinear and time-varying components, respectively. Results: Nonlinear and time-varying coil operation was simulated and the resulting magnetic fields for five harmonics were visualized. The fundamental frequency magnetic field resembles that of an ideal current loop. Impact: If validated for use with humans, the ADAPT Coil would significantly reduce barriers to clinical translation of X-nuclei research. The simulation method presented here represents a major step towards validation of the ADAPT Coil or any other nonlinear coil. |
| 1602.
 | 42 | A Simulation Framework for Comparison of Volumetric B1+ Mapping Methods James L. Kent1, Ladislav Valkovič2,3, Iulius Dragonu4, and Aaron T. Hess1
1Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom, 2Oxford Centre for Clinical Magnetic Resonance Research, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom, 3Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia, 4Research & Collaborations GB&I, Siemens Healthcare Ltd, Frimley, United Kingdom Keywords: High-Field MRI, High-Field MRI, B1+ Mapping, SatTFL, AFI, DREAM, Sandwich, SA2RAGE Motivation: To benefit from all the advantages that ultra-high field MRI offers, knowledge of the RF transmit field (B1+) is required. Many B1+ mapping methods have been developed, but no single method has become the ‘gold-standard’, with many sites opting for their own implementations. Goal(s): To evaluate five promising sequences and understand their sensitivity to B0, T1, flow and SNR on the accuracy and dynamic range of the measured B1+. Approach: SatTFL, Sandwich, SA2RAGE, AFI, and 3DREAM were investigated in MATLAB using open-source EPG and Bloch simulations. Results: A simulation framework to compare B1+ mapping sequences was developed. Impact: This simulation
framework is beneficial for understanding the impact of various factors on the accuracy
of B1+ mapping sequences and can help to inform better
pulse sequence design and parameter optimisation. |
| 1603.
 | 43 | A wireless resonator layer for high-resolution TMJ MRI at 1.5 T Haoqin Zhu1, Qiang Zhang2, Rangsong Li 3, Yuanyuan Chen3, Gong Zhang4, Ming Lu5, Yujie Ren6, and Xinqiang Yan5,7,8
1Research center, Sino Canada Health Institute Inc., Winnipeg, Manitoba, Canada, Winnipeg, MB, Canada, 2Physical Examination Center, The Affiliated Hospital of Inner Mongolia Medical University, Hohhot, China, 3Sino Canada Health Engineering Research Institute (Hefei) Ltd, Hefei, China, 4Hubei Key Laboratory of Intelligent Conveying Technology and Device, Hubei Polytechnic University, Huangshi, China, 5Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, United States, 6Department of Physics, The University of Winnipeg, Winnipeg, MB, Canada, 7Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, United States, 8Department of Electrical and Computer Engineering, Vanderbilt University, Nashville, TN, United States Keywords: RF Arrays & Systems, RF Arrays & Systems, TMJ, MRI, wireless coil, SNR, detune, RF coil Motivation: Most imaging facilities lack specialized coils, resulting in suboptimal TMJ MRI scans using head receive array. Goal(s): Developing flexible, cost-effective and efficient accessories to enhance TMJ MRI image using existing facilities. Approach: Improve TMJ MRI scans by incorporating an inductive wireless resonator insert into a head array. evaluating its performance against the head array alone using phantom and in vivo imaging. Results: The SNR increases by 5.3-fold times at the TMJ's articular fossa area and remains 2.4-fold at a 4cm depth, using a wireless resonator insert and head array combination, compared to a phased array. Impact: Combining
wireless RF resonators and phased arrays transformed MRI coils technology. It enhancing
SNR in specific regions like the thyroid and carotid artery, allowing parallel
imaging . This advancement ensures affordability, well-workflow,
and the adaptability to various magnetic field strengths. |
| 1604.
 | 44 | A Wireless Tx/Rx Litzcage coil for 1.5 T Knee MRI Haoqin Zhu1, Chenhao Zhou 2, Rangsong Li 2, Yuanyuan Chen2, Gong Zhang3, Yujie Ren4, and Xinqiang Yan5,6,7
1Research center, Sino Canada Health Institute Inc., Winnipeg, Manitoba, Canada, Winnipeg, MB, Canada, 2Sino Canada Health Engineering Research Institute (Hefei) Ltd, Hefei, China, 3Hubei Key Laboratory of Intelligent Conveying Technology and Device, Hubei Polytechnic University, Huangshi, China, 4Department of Physics, The University of Winnipeg, Winnipeg, MB, Canada, 5Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, United States, 6Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, United States, 7Department of Electrical and Computer Engineering, Vanderbilt University, Nashville, TN, United States Keywords: RF Arrays & Systems, RF Arrays & Systems, Knee, MRI, wireless coil, SNR, Tx/Rx, RF coil. Motivation: The conventional Tx/Rx knee coil optimizes transmission and reception using a complex dual-layer structure with multiple components, requiring local transmit power and a limited diameter. Goal(s): Developing a knee coil for that offers superior performance, patient-comfort, and affordable, without the need for a local transmit connection. Approach: Design a wireless Tx/Rx knee coil incorporating system body coil in transmit phase and a flex phased array during receive phase, evaluating its performance against the flex phased array alone using phantom and in vivo imaging. Results: Enhanced SNR is achieved when compared to a 13-channel flexible phased array, effectively eliminating wrap-around artifacts in knee image. Impact: The
advancement of inductive RF resonator technology with a wireless birdcage
resonator incorporating a Figure-of-Eight (Fo8) conductor design is aiming to
achieve cost-effective and improved performance for knee MRI which improves the
way of designing MRI coils and their applications |
| 1605.
 | 45 | A Birdcage Volume Transmit coil and 8 Channel Receive Array for Marmoset Brain Imaging at 7T Pedram Yazdanbakhsh1,2, Marcus Couch1,3, Maeva Gacoin2, Tyler Cook2,4, David A. Rudko2,5,6, and Justine Clery2,5,7
1McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, QC, Canada, 2Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada, 3Siemens Healthcare Limited, Montreal, QC, Canada, 4Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada, 5McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, Montreal, QC, Canada, 6Department of Biomedical Engineering, McGill University, Montreal, QC, Canada, 7Azrieli Centre for Autism Research, The Neuro, Montreal, QC, Canada Keywords: RF Arrays & Systems, Animals, Marmoset, High Field MRI, 7T Motivation: 7T promises a high SNR for high-resolution imaging of the small marmoset brain, which requires a custom RF coil. Goal(s): To develop a robust marmoset coil for 7T with an efficient volume transmit and receive array with a very high density and high filling factor. Approach: The coil was constructed, consisting of a volume transmit coil and receive array of 8 receive-only loops. The coil was tested with a phantom and a single anesthetized marmoset. Results: The transmit coil along with the optimized receive array for imaging the whole marmoset brain has been shown to produce images of high resolution and high SNR. Impact: A
shielded, band-pass birdcage transmit coil was designed and fabricated for
marmoset brain imaging at 7T. An 8-channel receive array consisting of eight
overlapped loops covering the whole brain of the marmoset was also built and
applied for signal reception. |
| 1606.
 | 46 | Optimizing the element numbers to improve dipole antenna array for 14 Tesla MRI Youheng Sun1, Miutian Wang2, Gang Yang3, and Winmin Wang2
1College of Future Technology, Peking University, Beijing, China, 2School of electronics, Peking University, Beijing, China, 3Institute of Biomedical Engineering, Peking University Shenzhen Graduate School, Shenzhen, China Keywords: RF Arrays & Systems, Simulations, Antenna array Motivation: The multi-channel RF coil scheme for 14T head imaging has not been defined yet. Goal(s): Our goal was to optimize the number of elements in the dipole antenna array in order to achieve optimal performance at 14T. Approach: We obtained the $$$\text{B}_{1}^{+}$$$ field distributions and SAR distributions of dipole antenna arrays with 8, 12, 16, and 20 channels through electromagnetic simulation, and compared their performances. Results: The results showed that the 12-channel dipole antenna array exhibits superior performance. Impact: The number of channels
in an RF coil at ultrahigh fields requires a trade-off between RF field
uniformity and inter-cell coupling; 12-channel dipole antenna array serves as a
suitable reference coil for 14T head imaging. |
| 1607.
 | 47 | Simulation of an 8-Channel Transmit Meander Stripline Array for Combined Head and Neck Imaging at 7 Tesla MRI Denis A. Mai1,2,3,4, Thomas M. Fiedler2, Neil Knöbel1,3,5, Luca Wessing1,6, Oliver Kraff1, Titus Lanz7, Harald H. Quick1,3, and Markus W. May1,3
1Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany, 2Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 3High-Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany, 4Institute of Electrical Engineering and Information Technology, South Westphalia University of Applied Sciences, Iserlohn, Germany, 5Institute of Electrical Engineering and Information Technology, FH Aachen – University of Applied Sciences, Aachen, Germany, 6Institute of Measuring and Sensor Technology, Ruhr West University of Applied Sciences, Mülheim a. d. Ruhr, Germany, 7RAPID Biomedical GmbH, Rimpar, Germany Keywords: High-Field MRI, High-Field MRI, Head & Neck/ENT, coil arrays Motivation: Covering the head-neck region in UHF MRI is challenging due to the limited number of only 8 parallel transmission (pTx) channels available in most UHF MR systems. Goal(s): Our goal was to design and simulate an 8-channel pTx coil for combined head/neck imaging at 7T. Approach: A geometrical setup for MR imaging with modified stripline elements was investigated by simulating the B1+ efficiency in a heterogenous tissue model.
Results: B1+ efficiency maxima of 0.31 μT/√W for head region and 0.13 μT/√W for neck region with SAR10g maximum of 1.21 W/kg for 1W stimulated input power per channel could be achieved. Impact: Meander stripline
elements can be overlapped while showing only low coupling, allowing a good
coverage of the head-neck area while only using 8 pTx elements in total. |
| 1608.
 | 48 | A Novel 8-channel Carotid Array with Two Wireless Resonators Insert for Magnetic Resonance Imaging at 5T Enhua Xiao1,2, Jiaxu Li1,2, Yingchao Tan1,2,3, Jiasheng Wang1,2, Jiafu Wei1,2, Ganghan Yang1,2, XiaoLiang Zhang1,4, Hairong Zheng1,2, Ye Li1,2, and Qiaoyan Chen1,2
1Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, shenzhen, China, 2Key Laboratory for Magnetic Resonance and Multimodality lmaging of Guangdong Province, shenzhen, China, 33. Shanghai United Imaging Healthcare, Shanghai, shenzhen, China, 44. Department of Biomedical Engineering, State University of New York at Buffalo, New York, NY, United States Keywords: RF Arrays & Systems, High-Field MRI, carotid array Motivation: Ultra-high field MRI is popular in brain imaging research. However, high-res imaging of carotid vessels and walls is not possible due to the lack of a carotid array. Goal(s): High-resolution imaging of the neck position at ultra-high fields Approach: In this study, carotid array with two wireless resonators insert was developed at 5T. Results: SNR was significantly improved using the novel coil in comparison with the only carotid array at 5T. Impact: An 8-channel carotid array with wireless resonators was designed for 5T magnetic resonance imaging. Water model imaging provides sufficient signal-to-noise ratio and resolution for high-field imaging, meeting the requirements for detailed neck artery disease feature descriptions. |