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Zidong Wei^1,2,3, Qiaoyan Chen^1,2, Qiang He³, Xiaoliang Zhang⁴, Xin Liu^1,2, Hairong Zheng^1,2, and Ye Li^1,2
1Paul C. Lauterbur Imaging Research Center, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China, ²Key Laboratory for Magnetic Resonance and Multimodality Imaging of Guangdong Province, Shenzhen, China, ³Shanghai United Imaging Healthcare, Shanghai, China, ⁴Department of Biomedical Engineering, State University of New York at Buffalo, New York, NY, United States

Keywords: High-Field MRI, Brain

The clinical experience, especially for subjects with claustrophobia, is not friendly when using the conventional shielded birdcage head coils on the ultra-high field. The closed structure also does not better support motion detection and motion correction, and other MRI functional applications. In this work, an optimized Open-Face birdcage head coil were designed based on EM simulations. The transmit efficiency, B1 uniformity, and SAR efficiency of the facial open-window birdcage coil with different configurations and a conventional shielded birdcage coil are compared. Finally, an optimized Open-Face birdcage head coil was built and evaluated on a whole body 5T MRI scanner.

Yingchao Tan^1,2,3, Qiaoyan Chen^1,2, Guangzu Xu³, Lei Zhang^1,2, Na Zhang^1,2, Xiaoliang Zhang⁴, Xin Liu^1,2, Hairong Zheng^1,2, and Ye Li^1,2
1Paul C. Lauterbur Imaging Research Center, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China, ²Key Laboratory for Magnetic Resonance and Multimodality Imaging of Guangdong Province, Shenzhen, China, ³Shanghai United Imaging Healthcare, Shanghai, China, ⁴Department of Biomedical Engineering, State University of New York at Buffalo, New York, NY, United States

Keywords: High-Field MRI, Head & Neck/ENT

Ultra-high field magnetic resonance imaging (MRI) has been increasing in use for human brain imaging. However, due to the absence of a head and neck neurovascular coil, joint imaging of intracranial and extracranial arterial vessel wall has not been applied in current ultra-high field MRI. In this study, a 48-channel head and neck receiver neurovascular coil for joint imaging of intracranial and extracranial arterial vessel wall at 5T was developed. Simultaneous high-resolution imaging of intracranial and extracranial arterial walls with an isotropic spatial resolution of 0.5 mm has been achieved, which further expands the application of ultra-high field imaging. 

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Jinghang Li¹, Nadim Farhat¹, Jacob P. Berardinelli¹, Joseph M. Mettenburg², Howard J. Aizenstein^1,3, Julia K. Kofler⁴, and Tamer S. Ibrahim^1,3
1Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States, ²Neuroradiology, University of Pittsburgh Medical Center, Pittsburgh, PA, United States, ³Psychiatry, University of Pittsburgh, Pittsburgh, PA, United States, ⁴Pathology, University of Pittsburgh Medical Center, Pittsburgh, PA, United States

Keywords: High-Field MRI, Ex-Vivo Applications

In this work, we present an image alignment pipeline that facilitates ongoing Alzheimer’s disease (AD) white matter pathology studies. Following our recently developed ex-vivo 7T cutting-guide container [1], in this work, we demonstrate a standardized alignment (between histopathology and ex-vivo 7T MRI) procedure that significantly reduces human effort and eliminate the need for manual alignment.

Caohui Duan¹, Xiangbing Bian¹, Kun Cheng¹, Song Wang¹, Linchang Liu¹, Jinhao Lyu¹, Jianxun Qu², Franck Mauconduit³, and Xin Lou^1
1Department of Radiology, Chinese PLA General Hospital, Beijing, China, ²MR Collaboration, Siemens Healthineers Ltd., Beijing, China, ³CEA NeuroSpin, Paris, France

Keywords: High-Field MRI, Parallel Transmit & Multiband

Ultra-high field 7T MRI provides a significant increase in signal-to-noise ratio and contrast for noninvasively visualizing the brain, but is challenging to use for whole-brain imaging. In this study, we investigated the clinical potential of parallel transmission universal pulses (UP) for improving visualization of whole-brain structures and pathology. Our results show that UP enables remarkable signal contrast improvement throughout the brain, which is promising to improve lesion detection (e.g., brain metastases) and structures visualization over the whole brain.

Jian-mei Fu¹, Jing Chen¹, Gui-dong Dai¹, and Yun-zhu Wu^2
1The Affiliated Hospital of Southwest Medical University, LUZHOU, China, ²MR Scientific Marketing, Siemens Healthineers Ltd, Shanghai, China

Keywords: High-Field MRI, Diffusion/other diffusion imaging techniques, Intravoxel Incoherent MotionImaging

 The objective of this study was to estimate the true diffusion and motion of molecules in the capillary network using the VIM biexponential model without injection of contrast media, three parameters (d value, d * value and F value) were obtained to evaluate the expression of prognostic molecules (ER, PR, Her-2, Ki-67) in breast cancer, which can guide the treatment of breast cancer more precisely.

 

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Saba Shirvani¹, Belinda Ding², Iulius Dragonu², and Christopher T. Rodgers^1
1Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom, ²Research and Collaboration UK, Siemens Healthcare Ltd, Frimley, United Kingdom

Keywords: High-Field MRI, MR Fingerprinting, Quantitative Imaging, Tissue Characterization, Brain

MR fingerprinting enables for robust simultaneous quantitative parametric mapping and is usually performed with spiral acquisitions. These are particularly sensitive to B₁ inhomogeneities and hence more susceptible at ultra high-field. To mitigate B₁ inhomogeneity effects, we implemented a Cartesian MRF approach. Cartesian 2D data collection time is somewhat slow, and we overcome this by demonstrating the feasibility of GRAPPA acceleration for applications in phantoms and in vivo. We present a fully sampled Cartesian data set in a phantom and in vivo, and we present the performance of increasing GRAPPA acceleration factors to reduce scan time significantly, without compromising image quality.

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Yunkun Zhao¹ and Xiaoliang Zhang^1
1Biomedical Engineering, State University of New York at Buffalo, Buffalo, NY, United States

Keywords: High-Field MRI, Non-Array RF Coils, Antennas & Waveguides

This study investigates the effect of conductor width of the RF coils to the EM coupling of an array. The results show that the wide conductor of the RF coils offers less EM coupling among resonant elements.

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Mohan Jayatilake¹, Christopher T Sica¹, Dhevin Karunanayaka¹, Anupa Ekanayaka², Biyar Ahmed¹, Rommy Elyan¹, and Prasanna Karunanayaka^1
1Pennsylvania State University College of Medicine, Hershey, PA, United States, ²Grodno State medical University, Grodno, Belarus

Keywords: High-Field MRI, High-Field MRI

In this study, we investigated the effects of ultra-high dielectric constant (uHDC) material for reducing noise and enhancing the B1 efficiency at 300 MHz for 1H nuclear applications at 7T. Using electromagnetic field simulations [CST Studio (2020) software] and imaging experiments, we estimated B1+ efficiency maps for a phantom mouse brain with and without uHDC material. Our results show significant enhancement of B1+ efficiency and Signal-to-Noise ratio (SNR) in the presence of the uHDC material.

Aleksander Fedotov¹, Pavel Tikhonov¹, Georgiy Solomakha¹, Victor Puchnin¹, Alena Shchelokova¹, and Anna Hurshkainen^1
1Department of Physics, ITMO University, St. Petersburg, Russian Federation

Keywords: High-Field MRI, RF Arrays & Systems

Wireless dedicated radiofrequency coils have recently proven to be a good alternative to conventional cable-connected coils due to compatibility with the scanners of different vendors. Due to significant increase of B1+ with respect to body coil manual calibration procedure needed often for operation of wireless coils.The goal of this work is to develop the first Rx-only wireless coil for dedicated breast MRI to overcome the aforementioned drawback. For that the passive detuning structure inserted to wireless Helmholtz resonator was designed and studied.

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Yaohui Wang¹, Qiuliang Wang¹, Ming Yan¹, Weimin Wang², Zhifeng Chen³, and Feng Liu^4
1Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, China, ²School of Electronics & Institute of Biomedical Engineering, Peking University & Shenzhen Graduate School, Beijing, China, ³Monash Biomedical Imaging, Monash University, Melbourne, Australia, ⁴School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, Australia

Keywords: Magnets (B0), Screening, Passive shielding

Passive shielding is a feasible approach to constrain the strong magnetic fluxes in ultrahigh field MRI superconducting magnets. However, an in-depth investigation of the passive shielding design is not well discussed in the literature and notably lacks nonlinear optimization design/analysis methods for this practice. This work developed a computation algorithm for passive shielding design, which uses an integral operation with nonlinear iteration. An exemplification for shielding a 9.4T whole-body MRI superconducting magnet showed the significant advantages of the proposed method over commercial packages. The optimized passive shielding scheme will be used in our future magnet engineering projects.

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Jagjit Sidhu¹, Alexander Smerglia², Labros Petropoulos², Tsinghua Zheng², Xiaoyu Yang², Jami Tatulinski², Ken Sakaie¹, Paul Taylor ², and Mark Lowe^1
1Cleveland Clinic, Cleveland, OH, United States, ²Quality Electrodynamics, Mayfield Heights, OH, United States

Keywords: High-Field MRI, Spinal Cord

MR imaging at 7T provides a greater signal intensity, which yields some combination of a greater signal-to-noise ratio, smaller voxel size, and/or faster scan times compared with lower field strengths. However, there remains room for improvement at 7T in terms of image homogeneity and a limited selection of coils. In this work, we summarize ongoing efforts to develop a single-transmit (STX) cervical spine (C-spine) and a parallel transmit (PTX) head coil. Both coils have a more open design with detachable anterior halves and larger physical dimensions.

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Yunkun Zhao¹ and Xiaoliang Zhang^1
1Biomedical Engineering, State University of New York at Buffalo, Buffalo, NY, United States

Keywords: High-Field MRI, RF Arrays & Systems

This study investigates the effect of lumped inductors used in RF resonant circuits on the magnetic field strength generated by the radiofrequency (RF) coils. The results show that the lumped inductors can reduce B1 fields in samples.

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Alexander Smerglia¹, Labros Petropoulos¹, Jami Tatulinski¹, Tsinghua Zheng¹, Xiaoyu Yang¹, Jagjit Sidhu², Ken Sakaie², and Mark Lowe^2
1Quality Electrodynamics (QED), Mayfield, OH, United States, ²Imaging Institute, Cleveland Clinic, Cleveland, OH, United States

Keywords: High-Field MRI, Brain, Spine, Imaging, Cerebellum

Several challenges are present when imaging the cervical spine in high-field MRI, such as achieving B1 coverage over the desired anatomy while maximizing efficiency of the transmitter. A cervical spine array coil with a volume transmit birdcage was built and tested on a system for improved transmit coverage and efficiency over previous prototypes. The coil consists of a partially shielded 22-rung birdcage transmitter and a 24 element receive RF array. A new mechanical design with larger eye windows improves the clinical experience. Improved transmit efficiency and complete B1 field coverage in the cervical spine region were confirmed through volunteer imaging.

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Zhiguang Mo^1,2, Xiaoping Zhang³, Huageng Liang³, Changjun Tie^1,2, Wen Xiao³, Qi Cao³, Chenchen Liu³, Xiaoliang Zhang⁴, and Ye Li^1,2
1Paul C. Lauterbur Imaging Research Center, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China, Shenzhen, China, ²Key Laboratory for Magnetic Resonance and Multimodality Imaging of Guangdong Province, Shenzhen, China, Shenzhen, China, ³Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China, ⁴Department of Biomedical Engineering, State University of New York at Buffalo, NY, United States., Buffalo, NY, United Stats, Buffalo, NY, United States

Keywords: High-Field MRI, Prostate

We made a three-channel endorectal coil for prostate imaging on the 5T magnetic resonance system and compared the imaging performance of the coils with the same structure on the 5T system and the 3T system. Prostate images at resolution of 0.78 mm × 0.78 mm × 2.5 mm were performed. In vivo prostate study shows that the endorectal coil works on the 5T system shows better image quality compared with the endorectal coil and surface coil array on the 3T system.

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Bu S Park¹ and Sunder Rajan^2
1FDA, Silver Spring, MD, United States, ²Division of Biomedical Physics (DBP), FDA, Silver Spring, MD, United States

Keywords: High-Field MRI, Electromagnetic Tissue Properties

To optimize MR image quality of 7T Body, the image region is divided into multiple ROIs, which can be independently optimized using transmit array optimization techniques to improve image intensity. Compared to the results of quadrature driving method, mean and SD of |Mt| in the full image (inner diameter of 500 mm) were improved 47% (Mean) and 48% (SD), whereas 94% (Max) and 97% (Mean) improved in the unaveraged SAR using the proposed method. The proposed method using multiple independently optimized ROIs and numerical simulations significantly improved uniformity of |Mt| body images at 7T.

Keywords: 7T Body, Uniformity, SAR

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Eulalia Serés Roig^1
1Laboratory of Functional and Metabolic Imaging (LIFMET), Institute of Physics (IPHYS), School of Basic Sciences (SB), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland

Keywords: Phantoms, Non-Proton

Largely neglected due to its low concentration, yet brain glycogen plays an active role in brain energy metabolism and may be involved in a variety of brain diseases. The application of ¹³C MRS along with ¹³C-glucose intravenous infusion is to date the forefront method for investigating brain glycogen metabolism in vivo. Notably, the C₁-resonances of glycogen and glucose have been detected non-invasively in the conscious human brain by ¹³C MRS at 4T after ¹³C-glucose infusion labelled at the C₁-carbon. In this study, we explore the potential of ¹³C MRS at 7T with broadband ¹H-decoupling towards measuring glycogen and glucose C₁-resonances.

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Max Joris Hubmann^1,2, Bilguun Nurzed³, Thoralf Niendorf³, Oliver Speck^2,4, and Holger Maune^2
1Siemens Healthineers GmbH, Magdeburg, Germany, ²Otto-von-Guericke University, Magdeburg, Germany, ³Berlin Ultra-High Field Facility, Max-Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany, ⁴Research Campus STIMULATE, Magdeburg, Germany

Keywords: Non-Array RF Coils, Antennas & Waveguides, Non-Array RF Coils, Antennas & Waveguides

This abstract proposes a standardized setup and four standardized metrics to increase 7T Tx RF antenna concept comparability and reproducibility, with the goal of a better technology transfer of antenna concepts across the MR community. Eight antenna concepts are evaluated based on power and SAR efficiency as well as mutual coupling and reliance on load changes using a rectangular phantom mimicking the average electromagnetic body properties. Based on the presented results, much information can be collected and deductions about each antenna's preferable ambits drawn. In conclusion, this work initiates a first standardized protocol for analyzing Tx RF antenna concepts. 

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Haiwei Chen¹, Lei Guo¹, Yang Gao², Zhiyan Quan³, Xiaocui Tang³, Sihong Pan³, Feng Liu¹, and Xiaotong Zhang^3
1the University of Queensland, Brisbane, Australia, ²School of Electronic Engineering (National Key Laboratory of Antennas and Microwave Technology) and Hangzhou Institute of Technology, Xidian University, Hangzhou, China, ³Zhejiang University, Hangzhou, China

Keywords: RF Arrays & Systems, RF Arrays & Systems

Dipole RF coil suffers from high peak local SAR and limited imaging coverage. In this work, a novel dipole structure is proposed. Compared with the fractionated dipole, the proposed design achieves a substantially enlarged B₁ field coverage and more than 25% SAR reduction by generating a uniform surface current on the coil. Experimental validations were conducted and agreed well with the simulation results.

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Santosh Kumar Maurya¹ and Rita Schmidt^2
1Brain Sciences, Weizmann Institute of Science, Rehovot, Israel, ²Department of Brain Sciences, Weizmann Institute of Science, Rehovot, Israel

Keywords: New Devices, High-Field MRI

Metamaterial-based structures constructed of conducting strips and a dielectric have already been used to locally increase the RF transmit field. In this study we characterize the RF field of such structures at 7T MRI. Configurations included either long strips (representing electric dipoles), or a matrix of short strips (representing magnetic dipoles). The RF field dependence on strip density and distribution was analyzed, providing insights useful for efficiency and coverage optimization. The configuration based on a matrix of short strips provides higher RF transmit efficiency, while the use of a non-uniform concave distribution of strips is useful to lower SAR.