Umberto Zanovello¹, Frank Seifert², Oriano Bottauscio¹, Lukas Winter², Luca Zilberti¹, and Bernd Ittermann^2
1Istituto Nazionale di Ricerca Metrologica (I.N.Ri.M.), Torino, Italy, ²Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany

The Electromagnetic/Circuit cosimulation method represents an effective strategy to address those problems where a radiative structure has to interact with external supporting circuitries.This method proved to be particularly valuable for MRI RF coil design where the supporting circuitry optimisation is generally of particular concern. CoSimPy, an open-source library conceived for Electromagnetic/Circuit cosimulations, is presented. CoSimPy is written in Python following an Object-oriented programming. This improves its scalability and easily allows interested scientists to collaborate, integrating and improving the library with other methods. CoSimPy is available under https://github.com/umbertozanovello/CoSimPy together with a detailed documentation providing guidelines and examples.

Yosuke Otake¹, Koichi Arai², Takeshi Taniguchi², Masayoshi Dohata², Takahide Shimoda², Kazuyuki Kato², and Hisaaki Ochi^1
1Innovative Technology Laboratory, FUJIFILM Healthcare Corporation, Tokyo, Japan, ²Radiation Diagnostic Systems Division, FUJIFILM Healthcare Corporation, Chiba, Japan

To improving the SNR and the g-factor in a vertical-field MRI, a multi-channel head coil has been developed. The coil consists of loop/dipole parallel RF coils (LDP) that improve the signal detection efficiency in the deep region of the subject in the vertical-field MRI. The performance of the coil was evaluated in a phantom experiment at 1.2T vertical-field MRI. The SNR and the g-factor of the coil using LDP were 1.2 and 1.2-2.9 times better than those of a conventional head coil, respectively. This technique will contribute to improve the performance of the vertical-field MRI.

Daniel Durst¹, Jürgen Nistler¹, and Rainer Schneider^1
1Siemens Healthcare GmbH, Erlangen, Germany

Birdcage coils used in MR imaging cause magnetic field strengths able to disturb electronic devices in the proximity to a MR system. Based on the principle of destructive superposition a configuration consisting of a main birdcage with additionally attached auxiliary birdcages is used to generate a field to reduce the magnetic field strength in the proximity of a MR system while maintaining the imaging quality. By electromagnetic simulations a reduction of up to 60 dB could be shown without drawbacks for the imaging performance if a distance of at least 25 cm between neighboring birdcages is retained.

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 Research Center for Biomedical Imaging, 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, shanghai, China, ⁴Department of Biomedical Engineering, State University of New York at Buffalo, Buffalo, NY, United States

Ultra-high field magnetic resonance imaging (MRI) of human brain with high resolution has been increasing used for clinical and research applications. Due to RF transmit homogeneity and specific absorption issues, clinical use of ultra-high field MRI were limited. In this work, a local quadrature birdcage/48-channel receiver coil assembly was designed and evaluated on a novel whole body 5T MRI scanner. The coil at 5T showed improved SNR, higher parallel acceleration capability and improved detection in vessel wall imaging compared to a 32-channel coil at a 3T commercial scanner.

Shao Che^1,2,3, Fuyi Fang², Kaida Dong², Shihong Han², and Ye Li^1,3
1Lauterbur Research Center for Biomedical Imaging, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China, ²United Imaging Healthcare, Shanghai, China, ³Key Laboratory for Magnetic Resonance and Multimodality Imaging of Guangdong Province, Shenzhen, China

Large field-of-view imaging of spine in ultra-high field 5.0T magnetic resonance imaging system is achieved with RF hardware design of an 8-channel volume transmit coil and a dedicated posterior spine array of 48 receive channels. The axial coverage and transmit homogeneity allow the use of refocusing pulses under specific-absorption ratio limits by safety regulations. Consequent high-resolution fast spin echo clinical images are acquired and compared with results on a commercial 3.0T scanner.

Yingchao Tan^1,2,3, Qiaoyan Chen^1,2, Rui Zhao³, Hai Lu³, Xianwen Fan³, Junyu Chen³, Xin Liu^1,2, Hairong Zheng^1,2, and Ye Li^1,2
1Paul C. Lauterbur Research Center for Biomedical Imaging, 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

To improve signal-to-noise ratio (SNR) and patient comfort, flexible coils need to be made of very light and flexible materials. In this study, a novel 24-channal ultra-light flexible receiver coil array was designed and constructed for human abdominal imaging at a 5T ultra-high field MRI system. The 24-channel ultra-light flexible coil showed much higher SNR and a better parallel acceleration capability compared to a 24-channel conventional receiver coil.  High quality human abdominal images were acquired by using the 24-channel ultra-light flexible coil.

Xinlian Chen¹, Navid P. Gandji², Christopher T. Sica², Gary W. Yang³, Parisa Lotfi Poshtgol², Hannes M Wiesner⁴, Xiao-Hong Zhu⁴, Michael Lanagan⁵, Wei Chen⁴, Qing X Yang², and Xuegang Xin^1
1Department of Biomedical Engineering, South China University of Technology, GuangDong, China, ²Departments of Neurosurgery and Radiology, College of Medicine, Pennsylvania State University, Hershey, PA, United States, ³Departments of Computer Science and Engineering, Pennsylvania State University, Hershey, PA, United States, ⁴Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States, ⁵Department of Engineering Science and Mechanics, Pennsylvania State University, Hershey, PA, United States

This investigation characterize the intrinsic resonance modes (IRM) in a helmet made from utrahigh dielectric constant (uHDC) material and their interactions with RF field produced by conventional array coils using numerical simulation. The RF field of the three lower order modes, TE, TM1 and TM2, were investigated.  TM1 mode produces uniform H-field in the transverse plane inside the helmet similar to that of a birdcage coil. TM2 mode produces a strong RF field but with a large gradient. Understanding of the IRMs of large uHDC structures such as helmets provides theoretical foundation for wider applications of uHDC materials RF engineering. 

Jifeng Chen¹, Ye Li¹, Jun Luo¹, Xin Liu¹, Xu Chu², and Hairong Zheng^1
1Lauterbur Imaging Research Center, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China, ²United Imaging Healthcare, Shanghai, China

Ultra-high filed (UHF) whole-body MRI technique usually utilizes radio frequency power amplifier (RFPA) with high power rating [1,2]. It requires high isolation among transmission channels as well as between transmitting and receiving (T/R) circuits. It also requires high B1 homogeneity [3] and signal-to-noise ratio (SNR). On the premise of meeting the abovementioned requirements, this paper presents an 8-channel high power pTx architecture, which can support the whole-body MRI system with high isolation among transmission channels as well as between T/R circuits.

Mingyan Li¹, Jin Jin^1,2, Ewald Weber¹, Craig Engstrom ³, Aurelien Destruel^1,4, Stuart Crozier¹, and Feng Liu^1
1School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, Australia, ²Siemens Healthineers, Brisbane, Australia, ³School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, Australia, ⁴The Center for Magnetic Resonance in Biology and Medicine, Aix-Marseille University, Marseille, France

Prostate imaging is challenging at 7T due to its small size seated deeply inside the pelvic region. As such, both transmit receive performance of the RF coils are heavily challenged. We have recently developed a new paddle-shape Integrated Multi-modal Antenna with coupled Radiating structures (I-MARS) allowing an ensemble of eight elements to be placed tightly together among each other and closely to the imaging region. In the current work, we demonstrate optimized work-flow and in vivo imaging results using such an 8-element paddle I-MARS coil with an upgraded MAGNETOM 7T Plus system.

xing yang¹, Xin Liu¹, feng du¹, Nan Li¹, Hairong Zheng¹, and Ye Li^1
1Shenzhen Institutes of Advanced Technology,Chinese Academy of Sciences, Shenzhen, China

 An ideal MRI study for early osteoarthritis should provide both structure imaging and functional imaging, which can show early morphologic degenerative changes and physiology changes of the cartilage. Most of previous dual-nuclei coils pushed the limits of non-proton nuclei sensitivity at the expense of 1H performance. To get high performance imaging for both nuclei, a novel dual-nuclei 1H/23Na coil array was developed. The bench test results show that all coils were sufficiently matched and decoupled, and the interference between sodium coils and proton coils was nearly negligible, thus can be expected to get high-resolution 1H imaging and quantitative 23Na imaging.

Nan Li^1,2, Feng Du^1,2, Xiaoliang Zhang³, Xin Liu^1,2, Hairong Zheng^1,2, and Ye Li^1,2
1Lauterbur 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, ³Department of Biomedical Engineering, State University of New York, Buffalo, NY, United States

The lower natural abundance and gyromagnetic ratios of non-hydrogen nuclei require the use of a highly efficient RF coil to optimize the quality of the MR image and spectroscopy. In this study, a new quadruple-tuned RF coil system capable of 1H / 19F / 23Na /31P imaging was proposed, including the inner high-pass birdcage coil (31P) and a triple-tuned outer four-ring birdcage coil (1H / 19F / 23Na). The feasibility and performance of this proposed RF coil were evaluated and validated by the numerical electromagnetic simulation in the scattering parameters and B1+field distributions.

Nan Li^1,2, Feng Du^1,2, Xiaoliang Zhang³, Xin Liu^1,2, Hairong Zheng^1,2, and Ye Li^1,2
1Lauterbur 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, ³Department of Biomedical Engineering, State University of New York, Buffalo, NY, United States

The lower natural abundance and gyromagnetic ratios of non-hydrogen nuclei require the use of a highly efficient RF coil to optimize the quality of the image. In this study, a novel triple-nuclear RF coil system capable of 1H / 19F / 23Na imaging was designed. The coil consists of a triple-tuned four-ring birdcage transmit coil and the tight fit local X-nuclei single-loop receive coils. A range of bench tests were performed by using the developed triple-nuclear coil. The performance evaluations showed that the coil system was appropriately tuned, matched and decoupled at 1H/19F/23NA frequencies when working simultaneously.

Mingyan Li¹, Ewald Weber¹, David Waddington², Shanshan Shan², Paul Liu², Bin Dong³, Craig Freakley¹, Stuart Crozier¹, and Feng Liu^1
1School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, Australia, ²ACRF Image X Institute, The University of Sydney, Sydney, Australia, ³Ingham Institute, Sydney, Australia

The hybrid MRI-Linac system demands dedicated radiolucent imaging coils to visualise and track tumours without interfering the Linac beams. A radiolucent whole-body transceive RF coil for the Australian inline MRI-Linac system has been previously developed and produced images with good quality. Recently, an 8-element torso RF coil array was manufactured to provide better SNR with fast imaging capability, which will facilitate real-time tumour tracking during radiotherapy. Initial imaging results acquired from the 1.0 T Australian MRI-Linac system on a phantom and a volunteer demonstrate the potential benefits of such a torso coil array for MRI-guided radiotherapies.

Zhiguang Mo¹, Xiaoliang Zhang², Changjun Tie¹, Huageng Liang³, Xiaoping Zhang³, Wen Xiao³, Qi Cao³, and Ye Li^1
1Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, 518055, China, Shenzhen, China, ²Department of Biomedical Engineering, State University of New York at Buffalo, NY, United States., Buffalo, NY, United Stats, Buffalo, NY, United States, ³Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China

We designed and fabricated a novel three-channel endorectal prostate coil and validated its feasibility of high-resolution magnetic resonance imaging (MRI) at 3T. A commercial 3T surface coil was used for comparison. Both phantom imaging and in-vivo prostate imaging show that the 3-channel endorectal coil provides an improved SNR than the external surface coil. Prostate images at resolution of 0.47 mm × 0.47 mm × 4.0 mm are acquired using the 3-channel endorectal coil to demonstrate the performance. With the improved SNR and multichannel design, the proposed endorectal coil could enable parallel imaging based fast imaging in prostate imaging studies.  

Haiwei Chen¹, Zhuang Xiong¹, Lei Guo¹, Xiaotong Zhang², and Feng Liu^1
1the University of Queensland, Brisbane, Australia, ²Zhejiang University, Hangzhou, China

Periodic passive components (PPC) such as metamaterials can improve SAR efficiency and B₁ penetration. However, due to the shorter RF wavelength in MRI, the performance of PPC is confined by the limited number of unit cells. In this work, a novel PPC structure has been proposed to combine with a high permittivity pad (HPP), so a larger number of unit cells can be used. The designed structure is excited by a dipole coil and compared with the case when a single HPP is used. It is observed that more than 50% SAR reduction can be achieved.

Eugene Koreshin¹, Denis Burov¹, and Pavel Seregin^1
1School of Physics and Engineering, ITMO University, Saint-Petersburg, Russian Federation

Metamaterials and metasurfaces, in particular, are gaining increasing popularity in recent years. One of the novel applications of metasurfaces are receive coils for magnetic resonance imaging. The major drawback of using such structures is the lack of parallel MRI capabilities due to the single-channel acquisition regime. In this work, we will demonstrate that it is possible to design a multichannel metasurface.

Xin Shao¹, Xiaodong Ma², Simin Liu¹, Kamil Ugurbil², Hua Guo¹, and Xiaoping Wu^2
1Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China, ²Center for Magnetic Resonance Research, Radiology, Medical School, University of Minnesota - Twin Cities, Minneapolis, MN, United States

It has been reported that combining ultrahigh field (UHF) with 3D imaging is beneficial for high-resolution imaging. Nevertheless, image quality may suffer from increased magnetic field inhomogeneity. Thus, we combined radiofrequency (RF) parallel transmission (pTx) with 3D simultaneous multi-slab (SMSlab) acquisition at 7T to get improved transmit field and optimal SNR efficiency concurrently. By simulation, it was proved that by using a 3-spoke RF pulses we could get 25% more uniform excitation magnitude than 2-spoke pulses (with almost the same RF peak power and identical pulse duration).

Ming Lu¹, John C. Gore^2,3, and Xinqiang Yan^2,3
1College of nuclear equipment and nuclear engineering, Yantai University, Yantai, China, ²Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, United States, ³Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, United States

In this work, we propose a novel “bump” design to further improve the coil robustness versus loadings.  For the loop-mode self-decoupled coil, the rotating magnetic field (composed of B_x and B_y) and electric field are mainly determined by the feed and arm conductors; the frequency shift that decreases coil robustness is mainly caused by the conductor with small-valued mode capacitors (referred to as mode conductor for short). Therefore, a bumped coil with a spaced  mode conductor but unchanged arm and feed conductors potentially provides more robust tuning/matching performance without decreasing coil efficiency.

Georgiy Solomakha¹, Svetlana Egorova¹, Alena Shchelokova¹, Egor Kretov¹, and Stanislav Glybovski^1
1Department of Physics and Engineering, ITMO University, Saint Petersburg, Russian Federation

This work proposes a novel transmit radiofrequency coil integrated into the scanner bore for whole-body MRI for 7 Tesla MRI based on patch antennas. Numerical studies with a homogeneous phantom demonstrated 4.5-fold higher transmit efficiency in the phantom center compared to the state-of-the-art bore integrated stripline array.