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Dubljevic N, Moore S, Lauzon ML, Souza R, Frayne R. Effect of MR head coil geometry on deep-learning-based MR image reconstruction. Magn Reson Med 2024; 92:1404-1420. [PMID: 38647191 DOI: 10.1002/mrm.30130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 04/02/2024] [Accepted: 04/07/2024] [Indexed: 04/25/2024]
Abstract
PURPOSE To investigate whether parallel imaging-imposed geometric coil constraints can be relaxed when using a deep learning (DL)-based image reconstruction method as opposed to a traditional non-DL method. THEORY AND METHODS Traditional and DL-based MR image reconstruction approaches operate in fundamentally different ways: Traditional methods solve a system of equations derived from the image data whereas DL methods use data/target pairs to learn a generalizable reconstruction model. Two sets of head coil profiles were evaluated: (1) 8-channel and (2) 32-channel geometries. A DL model was compared to conjugate gradient SENSE (CG-SENSE) and L1-wavelet compressed sensing (CS) through quantitative metrics and visual assessment as coil overlap was increased. RESULTS Results were generally consistent between experiments. As coil overlap increased, there was a significant (p < 0.001) decrease in performance in most cases for all methods. The decrease was most pronounced for CG-SENSE, and the DL models significantly outperformed (p < 0.001) their non-DL counterparts in all scenarios. CS showed improved robustness to coil overlap and signal-to-noise ratio (SNR) versus CG-SENSE, but had quantitatively and visually poorer reconstructions characterized by blurriness as compared to DL. DL showed virtually no change in performance across SNR and very small changes across coil overlap. CONCLUSION The DL image reconstruction method produced images that were robust to coil overlap and of higher quality than CG-SENSE and CS. This suggests that geometric coil design constraints can be relaxed when using DL reconstruction methods.
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Affiliation(s)
- Natalia Dubljevic
- Department of Biomedical Engineering, University of Calgary, Calgary, Alberta, Canada
- Seaman Family MR Research Centre, Foothills Medical Centre, Calgary, Alberta, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Stephen Moore
- Seaman Family MR Research Centre, Foothills Medical Centre, Calgary, Alberta, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
- O'Brien Centre for the Health Sciences, Cumming School of Medicine, Calgary, Alberta, Canada
| | - Michel Louis Lauzon
- Seaman Family MR Research Centre, Foothills Medical Centre, Calgary, Alberta, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
- Radiology and Clinical Neuroscience, University of Calgary, Calgary, Alberta, Canada
| | - Roberto Souza
- Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
- Department of Electrical and Software Engineering, University of Calgary, Calgary, Alberta, Canada
| | - Richard Frayne
- Department of Biomedical Engineering, University of Calgary, Calgary, Alberta, Canada
- Seaman Family MR Research Centre, Foothills Medical Centre, Calgary, Alberta, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
- Radiology and Clinical Neuroscience, University of Calgary, Calgary, Alberta, Canada
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2
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Lu M, Yang Y, Chai S, Yan X. Reproducible and highly miniaturized bazooka RF Balun using a printed capacitor. Magn Reson Med 2024. [PMID: 39188192 DOI: 10.1002/mrm.30268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 08/05/2024] [Accepted: 08/06/2024] [Indexed: 08/28/2024]
Abstract
PURPOSE There is currently a strong trend in developing RF coils that are high-density, lightweight, and highly flexible. In addition to the resonator structure of the RF coil itself, the balun or cable trap circuit serves as another essential element in the functionality and sensitivity of RF coils. This study explores the development and application of reproducible highly miniaturized baluns in RF coil design. METHODS We introduce a novel approach to producing Bazooka baluns with printed coaxial capacitors, enabling the achievement of significant capacitance per unit length. Rigorous electromagnetic simulations and thorough hardware fabrication validate the efficacy of the proposed design across various magnetic field strengths, including 1.5 T, 3 T, and 7 T MRI systems. RESULTS Bench testing reveals that the proposed balun can achieve an acceptable common-mode rejection ratio even when it is highly miniaturized. The use of printed capacitors allows for a notable reduction in balun length and ensures high reproducibility. Findings demonstrate that the proposed balun exhibits no RF field distortion even when placed close to the sample, making it suitable for flexible coils, wearable coils, and high-density coils, particularly in high-field MRI. CONCLUSION The reproducibility inherent in the manufacturing process of printed coaxial capacitors allows for simple fabrication and ensures consistency in production. These advancements pave the way for the development of flexible coils, wearable coils, and high-density coils.
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Affiliation(s)
- Ming Lu
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Yijin Yang
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Electrical and Computer Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Shuyang Chai
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Electrical and Computer Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Xinqiang Yan
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Electrical and Computer Engineering, Vanderbilt University, Nashville, Tennessee, USA
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3
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Zhu X, Wu K, Xie X, Anderson SW, Zhang X. A robust near-field body area network based on coaxially-shielded textile metamaterial. Nat Commun 2024; 15:6589. [PMID: 39097604 PMCID: PMC11297955 DOI: 10.1038/s41467-024-51061-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Accepted: 07/25/2024] [Indexed: 08/05/2024] Open
Abstract
A body area network involving wearable sensors distributed around the human body can continuously monitor physiological signals, finding applications in personal healthcare and athletic evaluation. Existing solutions for near-field body area networks, while facilitating reliable and secure interconnection among battery-free sensors, face challenges including limited spectral stability against external interference. Here we demonstrate a textile metamaterial featuring a coaxially-shielded internal structure designed to mitigate interference from extraneous loadings. The metamaterial can be patterned onto clothing to form a scalable, customizable network, enabling communication between near-field reading devices and battery-free sensing nodes placed within the network. Proof of concept demonstration shows the metamaterial's robustness against mechanical deformation and exposure to lossy, conductive saline solutions, underscoring its potential applications in wet environments, particularly in athletic activities involving water or significant perspiration, offering insights for the future development of radio frequency components for a robust body area network at a system level.
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Affiliation(s)
- Xia Zhu
- Department of Mechanical Engineering, Boston University, Boston, MA, USA
- Photonics Center, Boston University, Boston, MA, USA
| | - Ke Wu
- Department of Mechanical Engineering, Boston University, Boston, MA, USA
- Photonics Center, Boston University, Boston, MA, USA
| | - Xiaohang Xie
- Department of Mechanical Engineering, Boston University, Boston, MA, USA
- Photonics Center, Boston University, Boston, MA, USA
| | - Stephan W Anderson
- Photonics Center, Boston University, Boston, MA, USA
- Chobanian & Avedisian School of Medicine, Boston University Medical Campus, Boston, MA, USA
| | - Xin Zhang
- Department of Mechanical Engineering, Boston University, Boston, MA, USA.
- Photonics Center, Boston University, Boston, MA, USA.
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4
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Zhu X, Wu K, Anderson SW, Zhang X. Wearable Coaxially-Shielded Metamaterial for Magnetic Resonance Imaging. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2313692. [PMID: 38569592 DOI: 10.1002/adma.202313692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 03/04/2024] [Indexed: 04/05/2024]
Abstract
Recent advancements in metamaterials have yielded the possibility of a wireless solution to improve signal-to-noise ratio (SNR) in magnetic resonance imaging (MRI). Unlike traditional closely packed local coil arrays with rigid designs and numerous components, these lightweight, cost-effective metamaterials eliminate the need for radio frequency cabling, baluns, adapters, and interfaces. However, their clinical adoption is limited by their low sensitivity, bulky physical footprint, and limited, specific use cases. Herein, a wearable metamaterial developed using commercially available coaxial cable, designed for a 3.0 T MRI system is introduced. This metamaterial inherits the coaxially-shielded structure of its constituent cable, confining the electric field within and mitigating coupling to its surroundings. This ensures safer clinical adoption, lower signal loss, and resistance to frequency shifts. Weighing only 50 g, the metamaterial maximizes its sensitivity by conforming to the anatomical region of interest. MRI images acquired using this metamaterial with various pulse sequences achieve an SNR comparable or even surpass that of a state-of-the-art 16-channel knee coil. This work introduces a novel paradigm for constructing metamaterials in the MRI environment, paving the way for the development of next-generation wireless MRI technology.
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Affiliation(s)
- Xia Zhu
- Department of Mechanical Engineering, Boston University, Boston, MA, 02215, USA
- Photonics Center, Boston University, Boston, MA, 02215, USA
| | - Ke Wu
- Department of Mechanical Engineering, Boston University, Boston, MA, 02215, USA
- Photonics Center, Boston University, Boston, MA, 02215, USA
| | - Stephan W Anderson
- Photonics Center, Boston University, Boston, MA, 02215, USA
- Department of Radiology, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, 02118, USA
| | - Xin Zhang
- Department of Mechanical Engineering, Boston University, Boston, MA, 02215, USA
- Photonics Center, Boston University, Boston, MA, 02215, USA
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Motovilova E, Ching T, Vincent J, Tan ET, Taracila V, Robb F, Hashimoto M, Sneag DB, Winkler SA. Design and Dynamic In Vivo Validation of a Multi-Channel Stretchable Liquid Metal Coil Array. MATERIALS (BASEL, SWITZERLAND) 2024; 17:3325. [PMID: 38998405 PMCID: PMC11243347 DOI: 10.3390/ma17133325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2024] [Revised: 07/03/2024] [Accepted: 07/03/2024] [Indexed: 07/14/2024]
Abstract
Recent developments in the field of radiofrequency (RF) coils for magnetic resonance imaging (MRI) offer flexible and patient-friendly solutions. Previously, we demonstrated a proof-of-concept single-element stretchable coil design based on liquid metal and a self-tuning smart geometry. In this work, we numerically analyze and experimentally study a multi-channel stretchable coil array and demonstrate its application in dynamic knee imaging. We also compare our flexible coil array to a commonly used commercial rigid coil array. Our numerical analysis shows that the proposed coil array maintains its resonance frequency (<1% variation) and sensitivity (<6%) at various stretching configurations from 0% to 30%. We experimentally demonstrate that the signal-to-noise ratio (SNR) of the acquired MRI images is improved by up to four times with the stretchable coil array due to its conformal and therefore tight-fitting nature. This stretchable array allows for dynamic knee imaging at different flexion angles, infeasible with traditional, rigid coil arrays. These findings are significant as they address the limitations of current rigid coil technology, offering a solution that enhances patient comfort and image quality, particularly in applications requiring dynamic imaging.
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Affiliation(s)
- Elizaveta Motovilova
- Department of Radiology, Weill Cornell Medicine, New York, NY 10065, USA
- Department of Radiology and Imaging, Hospital for Special Surgery, New York, NY 10021, USA
| | - Terry Ching
- Pillar of Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore
- Digital Manufacturing and Design (DManD) Centre, Singapore University of Technology and Design, Singapore 487372, Singapore
- Department of Biomedical Engineering, National University of Singapore, Singapore 117583, Singapore
| | | | - Ek Tsoon Tan
- Department of Radiology and Imaging, Hospital for Special Surgery, New York, NY 10021, USA
| | | | | | - Michinao Hashimoto
- Pillar of Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore
- Digital Manufacturing and Design (DManD) Centre, Singapore University of Technology and Design, Singapore 487372, Singapore
| | - Darryl B Sneag
- Department of Radiology and Imaging, Hospital for Special Surgery, New York, NY 10021, USA
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Budé LMI, Steensma BR, Zivkovic I, Raaijmakers AJE. The coax monopole antenna: A flexible end-fed antenna for ultrahigh field transmit/receive arrays. Magn Reson Med 2024; 92:361-373. [PMID: 38376359 DOI: 10.1002/mrm.30036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 01/15/2024] [Accepted: 01/15/2024] [Indexed: 02/21/2024]
Abstract
PURPOSE The coax monopole antenna is presented for body imaging at 7 T. The antenna is fed at one end, eliminating the possibility of cable-coil coupling and simplifying cable routing. Additionally, its flexibility improves loading to the subject. METHODS Like the coax dipole antenna, an interruption in the shield of the coaxial cable allows the current to extend to the outside of the shield, generating a B1 + field. Matching is achieved using a single inductor at the distal side, and a cable trap enforces the desired antenna length. Finite difference time domain simulations are employed to optimize the design parameters. Phantom measurements are conducted to determine the antenna's B1 + efficiency and to find the S-parameters in straight and bent positions. Eight-channel simulations and measurements are performed for prostate imaging. RESULTS The optimal configuration is a length of 360 mm with a gap position of 40 mm. Simulation data show higher B1 + levels for the coax monopole (20% in the prostate), albeit with a 5% lower specific absorbance rate efficiency, compared to the fractionated dipole antenna. The S11 of the coax monopole exhibits remarkable robustness to loading changes. In vivo prostate imaging demonstrates B1 + levels of 10-14 μT with an input power of 8 × 800 W, which is comparable to the fractionated dipole antenna. High-quality images and acceptable coupling levels were achieved. CONCLUSION The coax monopole is a novel, flexible antenna for body imaging at 7 T. Its simple design incorporates a single inductor at the distal side to achieve matching, and one-sided feeding greatly simplifies cable routing.
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Affiliation(s)
- Lyanne M I Budé
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
- Department of Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Bart R Steensma
- Division of Imaging and Oncology, UMC Utrecht, Utrecht, The Netherlands
| | - Irena Zivkovic
- Department of Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Alexander J E Raaijmakers
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
- Division of Imaging and Oncology, UMC Utrecht, Utrecht, The Netherlands
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7
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Vazquez R, Motovilova E, Winkler SA. Stretchable Sensor Materials Applicable to Radiofrequency Coil Design in Magnetic Resonance Imaging: A Review. SENSORS (BASEL, SWITZERLAND) 2024; 24:3390. [PMID: 38894182 PMCID: PMC11174967 DOI: 10.3390/s24113390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 05/19/2024] [Accepted: 05/21/2024] [Indexed: 06/21/2024]
Abstract
Wearable sensors are rapidly gaining influence in the diagnostics, monitoring, and treatment of disease, thereby improving patient outcomes. In this review, we aim to explore how these advances can be applied to magnetic resonance imaging (MRI). We begin by (i) introducing limitations in current flexible/stretchable RF coils and then move to the broader field of flexible sensor technology to identify translatable technologies. To this goal, we discuss (ii) emerging materials currently used for sensor substrates, (iii) stretchable conductive materials, (iv) pairing and matching of conductors with substrates, and (v) implementation of lumped elements such as capacitors. Applicable (vi) fabrication methods are presented, and the review concludes with a brief commentary on (vii) the implementation of the discussed sensor technologies in MRI coil applications. The main takeaway of our research is that a large body of work has led to exciting new sensor innovations allowing for stretchable wearables, but further exploration of materials and manufacturing techniques remains necessary, especially when applied to MRI diagnostics.
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Affiliation(s)
- Rigoberto Vazquez
- Department of Biomedical Engineering, Cornell University, Ithaca, NY 10065, USA
- Department of Radiology, Weill Cornell Medicine, New York, NY 10065, USA
| | | | - Simone Angela Winkler
- Department of Biomedical Engineering, Cornell University, Ithaca, NY 10065, USA
- Department of Radiology, Weill Cornell Medicine, New York, NY 10065, USA
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8
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Payne K, Zhao Y, Bhosale AA, Zhang X. Dual-Tuned Coaxial-Transmission-Line RF Coils for Hyperpolarized 13C and Deuterium 2H Metabolic MRS Imaging at Ultrahigh Fields. IEEE Trans Biomed Eng 2024; 71:1521-1530. [PMID: 38090865 PMCID: PMC11095995 DOI: 10.1109/tbme.2023.3341760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2023]
Abstract
OBJECTIVE Information on the metabolism of tissues in healthy and diseased states plays a significant role in the detection and understanding of tumors, neurodegenerative diseases, diabetes, and other metabolic disorders. Hyperpolarized carbon-13 magnetic resonance imaging (13C-HPMRI) and deuterium metabolic imaging (2H-DMI) are two emerging X-nuclei used as practical imaging tools to investigate tissue metabolism. However due to their low gyromagnetic ratios (ɣ13C = 10.7 MHz/T; ɣ2H = 6.5 MHz/T) and natural abundance, such method required a sophisticated dual-tuned radiofrequency (RF) coil. METHODS Here, we report a dual-tuned coaxial transmission line (CTL) RF coil agile for metabolite information operating at 7T with independent tuning capability. The design analysis has demonstrated how both resonant frequencies can be individually controlled by simply varying the constituent of the design parameters. RESULTS Numerical results have demonstrated a broadband tuning range capability, covering most of the X-nucleus signal, especially the 13C and 2H spectra at 7T. Furthermore, in order to validate the feasibility of the proposed design, both dual-tuned 1H/13C and 1H/2H CTLs RF coils are fabricated using a semi-flexible RG-405 .086" coaxial cable and bench test results (scattering parameters and magnetic field efficiency/distribution) are successfully obtained. CONCLUSION The proposed dual-tuned RF coils reveal highly effective magnetic field obtained from both proton and heteronuclear signal which is crucial for accurate and detailed imaging. SIGNIFICANCE The successful development of this new dual-tuned RF coil technique would provide a tangible and efficient tool for ultrahigh field metabolic MR imaging.
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Payne K, Zhao Y, Bhosale AA, Zhang X. Eight-channel dual-tuned coaxial-transmission-line coils array for human head imaging at 10.5 Tesla. PROCEEDINGS OF THE INTERNATIONAL SOCIETY FOR MAGNETIC RESONANCE IN MEDICINE ... SCIENTIFIC MEETING AND EXHIBITION. INTERNATIONAL SOCIETY FOR MAGNETIC RESONANCE IN MEDICINE. SCIENTIFIC MEETING AND EXHIBITION 2024; 32:0465. [PMID: 38798757 PMCID: PMC11127717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Affiliation(s)
- Komlan Payne
- Department of Biomedical Engineering, State University of New York at Buffalo, Buffalo, NY, United States
| | - Yunkun Zhao
- Department of Biomedical Engineering, State University of New York at Buffalo, Buffalo, NY, United States
| | - Aditya Ashok Bhosale
- Department of Biomedical Engineering, State University of New York at Buffalo, Buffalo, NY, United States
| | - Xiaoliang Zhang
- Department of Biomedical Engineering, State University of New York at Buffalo, Buffalo, NY, United States
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Vliem J, Xiao Y, Wenz D, Xin L, Teeuwise W, Ruytenberg T, Webb A, Zivkovic I. Twisted pair transmission line coil - a flexible, self-decoupled and robust element for 7 T MRI. Magn Reson Imaging 2024; 108:146-160. [PMID: 38364973 DOI: 10.1016/j.mri.2024.02.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 02/08/2024] [Accepted: 02/08/2024] [Indexed: 02/18/2024]
Abstract
OBJECTIVE This study evaluates the performance of a twisted pair transmission line coil as a transceive element for 7 T MRI in terms of physical flexibility, robustness to shape deformations, and interelement decoupling. METHODS Each coil element was created by shaping a twisted pair of wires into a circle. One wire was interrupted at the top, while the other was interrupted at the bottom, and connected to the matching circuit. Electromagnetic simulations were conducted to determine the optimal number of twists per length (in terms of B₁+ field efficiency, SAR efficiency, sensitivity to elongation, and interelement decoupling properties) and for investigating the fundamental operational principle of the coil through fields streamline visualisation. A comparison between the twisted pair coil and a conventional loop coil in terms of B₁+ fields, maxSAR₁₀g, and stability of S₁₁ when the coil was deformed was performed. Experimentally measured interelement coupling between individual elements of multichannel arrays was also investigated. RESULTS Increasing the number of twists per length resulted in a more physically robust coil. Poynting vector streamline visualisation showed that the twisted pair coil concentrated most of the energy in the near field. The twisted pair coil exhibited comparable B₁+ fields and improved maxSAR₁₀g to the conventional coil but demonstrated exceptional stability with respect to coil deformation and a strong self-decoupling nature when placed in an array configuration. DISCUSSION The findings highlight the robustness of the twisted pair coil, showcasing its stability under shape variations. This coil holds great potential as a flexible RF coil for various imaging applications using multiple-element arrays, benefiting from its inherent decoupling.
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Affiliation(s)
- Jules Vliem
- Department of Electrical Engineering, Eindhoven University of Technology, the Netherlands
| | - Ying Xiao
- CIBM Center for Biomedical Imaging, Lausanne, Switzerland; École Polytechnique Fédérale de Lausanne (EPFL), Animal Imaging and Technology, Lausanne, Switzerland
| | - Daniel Wenz
- CIBM Center for Biomedical Imaging, Lausanne, Switzerland; École Polytechnique Fédérale de Lausanne (EPFL), Animal Imaging and Technology, Lausanne, Switzerland
| | - Lijing Xin
- CIBM Center for Biomedical Imaging, Lausanne, Switzerland; École Polytechnique Fédérale de Lausanne (EPFL), Animal Imaging and Technology, Lausanne, Switzerland
| | - Wouter Teeuwise
- C.J. Gorter MRI Centre, Department of Radiology, Leiden University Medical Center Leiden, the Netherlands
| | - Thomas Ruytenberg
- C.J. Gorter MRI Centre, Department of Radiology, Leiden University Medical Center Leiden, the Netherlands
| | - Andrew Webb
- C.J. Gorter MRI Centre, Department of Radiology, Leiden University Medical Center Leiden, the Netherlands
| | - Irena Zivkovic
- Department of Electrical Engineering, Eindhoven University of Technology, the Netherlands.
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Lakshmanan K, Wang B, Walczyk J, Collins CM, Brown R. Three-row MRI receive array with remote circuitry to preserve radiation transparency. Phys Med Biol 2024; 69:10.1088/1361-6560/ad388c. [PMID: 38537307 PMCID: PMC11071057 DOI: 10.1088/1361-6560/ad388c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 03/27/2024] [Indexed: 04/18/2024]
Abstract
Objective.Up to this point, 1.5 T linac-compatible coil array layouts have been restricted to one or two rows of coils because of the desire to place radiation-opaque circuitry adjacent to the coils and outside the window through which the linac beam travels. Such layouts can limit parallel imaging performance. The purpose of this work was to design and build a three-row array in which remotely located circuits permitted a central row of coils while preserving the radiolucent window.Approach.The remote circuits consisted of a phase shifter to cancel the phase introduced by the coaxial link between the circuit and coil, followed by standard components for tuning, matching, detuning, and preamplifier decoupling. Tests were performed to compare prototype single-channel coils with remote or local circuits, which were followed by tests comparing two and three-row arrays .Main results.The single-channel coil with the remote circuit maintained 85% SNR at depths of 30 mm or more as compared to a coil with local circuit. The three-row array provided similar SNR as the two-row array, along with geometry factor advantages for parallel imaging acceleration in the head-foot direction.Significance.The remote circuit strategy could potentially support future MR-linac arrays by allowing greater flexibility in array layout compared to those confined by local circuits, which can be leveraged for parallel imaging acceleration.
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Affiliation(s)
- Karthik Lakshmanan
- Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University Grossman School of Medicine, New York, NY, United States
- Center for Biomedical Imaging, Department of Radiology, New York University Grossman School of Medicine, New York, NY, United States
| | - Bili Wang
- Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University Grossman School of Medicine, New York, NY, United States
- Center for Biomedical Imaging, Department of Radiology, New York University Grossman School of Medicine, New York, NY, United States
| | - Jerzy Walczyk
- Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University Grossman School of Medicine, New York, NY, United States
- Center for Biomedical Imaging, Department of Radiology, New York University Grossman School of Medicine, New York, NY, United States
| | - Christopher M. Collins
- Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University Grossman School of Medicine, New York, NY, United States
- Center for Biomedical Imaging, Department of Radiology, New York University Grossman School of Medicine, New York, NY, United States
| | - Ryan Brown
- Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University Grossman School of Medicine, New York, NY, United States
- Center for Biomedical Imaging, Department of Radiology, New York University Grossman School of Medicine, New York, NY, United States
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12
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Nohava L, Czerny R, Tik M, Wurzer D, Laistler E, Frass-Kriegl R. Citizen science approach to assessing patient perception of MRI with flexible radiofrequency coils. Sci Rep 2024; 14:2811. [PMID: 38307928 PMCID: PMC10837436 DOI: 10.1038/s41598-024-53364-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 01/30/2024] [Indexed: 02/04/2024] Open
Abstract
Magnetic Resonance Imaging (MRI) is a major medical imaging modality, which is non-invasive and provides unique soft tissue contrast without ionizing radiation. The successful completion of MRI exams critically depends on patient compliance, and, thus patient comfort. The design, appearance and usability of local MRI radiofrequency (RF) coils potentially influences the patients' perception of the exam. However, systematic investigations and empirical evidence for these aspects are missing. A questionnaire specifically evaluating the impact of RF coils on patient comfort in MRI would be a valuable addition to clinical studies comparing the performance of novel flexible RF coils with standard rigid coils. This paper describes the development of such a questionnaire in the scope of a citizen science (CS) initiative conducted with a group of students at the upper secondary school level. In this work, the CS initiative is presented in the format of a case report and its impact on scientific projects and the students' education is outlined. The resulting questionnaire is made available in German and English so as to be directly applicable by researchers working on the clinical evaluation of novel RF coils or the comfort evaluation of specific hardware setups in general.
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Affiliation(s)
- Lena Nohava
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Raphaela Czerny
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Martin Tik
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Dagmar Wurzer
- Bundes(real)gymnasium BG/BRG Keimgasse, Mödling, Austria
| | - Elmar Laistler
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Roberta Frass-Kriegl
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.
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Overson DK, Darnell D, Robb F, Song AW, Truong TK. Flexible multi-purpose integrated RF/shim coil array for MRI and localized B 0 shimming. Magn Reson Med 2024; 91:842-849. [PMID: 37849021 PMCID: PMC10842526 DOI: 10.1002/mrm.29891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 09/22/2023] [Accepted: 09/27/2023] [Indexed: 10/19/2023]
Abstract
PURPOSE To develop a flexible, lightweight, and multi-purpose integrated parallel reception, excitation, and shimming (iPRES) coil array that can conform to the subject's anatomy and perform MR imaging and localized B0 shimming in different anatomical regions with a high SNR, shimming performance, ease of positioning, and subject comfort. METHODS A four-channel flexible iPRES coil array was constructed by enabling RF and direct currents to flow on the same flexible coil elements for imaging and shimming, respectively. Shimming experiments were performed with the coil array wrapped around the knee or neck of healthy subjects to demonstrate its high shimming performance and versatility. Additionally, its SNR and shimming performance in the knee were compared to those obtained with the coil array wrapped around a larger rigid tube designed to fit most knee sizes. RESULTS Shimming with the coil array wrapped around the knee or neck resulted in an average reduction in B0 RMSE of 50.1% and 40.5% relative to first-order and second-order spherical harmonic shimming, respectively, and substantially reduced distortions in DWI images. In contrast, shimming the knee with the coil array wrapped around the rigid tube only provided a 29.6% reduction in B0 RMSE, whereas the SNR was reduced by 58.7%. CONCLUSION The flexible iPRES coil array can conform to different anatomical regions and perform imaging and localized B0 shimming with a higher SNR, shimming performance, ease of positioning, and comfort compared to a rigid iPRES coil array, which should be valuable for many applications throughout the human body.
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Affiliation(s)
- Devon Karl Overson
- Brain Imaging and Analysis Center, Duke University, Durham, North Carolina, USA
- Medical Physics Graduate Program, Duke University, Durham, North Carolina, USA
| | - Dean Darnell
- Brain Imaging and Analysis Center, Duke University, Durham, North Carolina, USA
- Medical Physics Graduate Program, Duke University, Durham, North Carolina, USA
| | | | - Allen W Song
- Brain Imaging and Analysis Center, Duke University, Durham, North Carolina, USA
- Medical Physics Graduate Program, Duke University, Durham, North Carolina, USA
| | - Trong-Kha Truong
- Brain Imaging and Analysis Center, Duke University, Durham, North Carolina, USA
- Medical Physics Graduate Program, Duke University, Durham, North Carolina, USA
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14
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Yoon MA, Gold GE, Chaudhari AS. Accelerated Musculoskeletal Magnetic Resonance Imaging. J Magn Reson Imaging 2023. [PMID: 38156716 DOI: 10.1002/jmri.29205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 12/13/2023] [Accepted: 12/14/2023] [Indexed: 01/03/2024] Open
Abstract
With a substantial growth in the use of musculoskeletal MRI, there has been a growing need to improve MRI workflow, and faster imaging has been suggested as one of the solutions for a more efficient examination process. Consequently, there have been considerable advances in accelerated MRI scanning methods. This article aims to review the basic principles and applications of accelerated musculoskeletal MRI techniques including widely used conventional acceleration methods, more advanced deep learning-based techniques, and new approaches to reduce scan time. Specifically, conventional accelerated MRI techniques, including parallel imaging, compressed sensing, and simultaneous multislice imaging, and deep learning-based accelerated MRI techniques, including undersampled MR image reconstruction, super-resolution imaging, artifact correction, and generation of unacquired contrast images, are discussed. Finally, new approaches to reduce scan time, including synthetic MRI, novel sequences, and new coil setups and designs, are also reviewed. We believe that a deep understanding of these fast MRI techniques and proper use of combined acceleration methods will synergistically improve scan time and MRI workflow in daily practice. EVIDENCE LEVEL: 3 TECHNICAL EFFICACY: Stage 1.
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Affiliation(s)
- Min A Yoon
- Department of Radiology, Stanford University, Stanford, California, USA
- Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, South Korea
| | - Garry E Gold
- Department of Radiology, Stanford University, Stanford, California, USA
- Department of Orthopaedic Surgery, Stanford University, Stanford, California, USA
- Department of Bioengineering, Stanford University, Stanford, California, USA
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15
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Obermann M, Nohava L, Frass-Kriegl R, Soanca O, Ginefri JC, Felblinger J, Clauser P, Baltzer PA, Laistler E. Panoramic Magnetic Resonance Imaging of the Breast With a Wearable Coil Vest. Invest Radiol 2023; 58:799-810. [PMID: 37227137 PMCID: PMC10581436 DOI: 10.1097/rli.0000000000000991] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 04/21/2023] [Indexed: 05/26/2023]
Abstract
BACKGROUND Breast cancer, the most common malignant cancer in women worldwide, is typically diagnosed by x-ray mammography, which is an unpleasant procedure, has low sensitivity in women with dense breasts, and involves ionizing radiation. Breast magnetic resonance imaging (MRI) is the most sensitive imaging modality and works without ionizing radiation, but is currently constrained to the prone imaging position due to suboptimal hardware, therefore hampering the clinical workflow. OBJECTIVES The aim of this work is to improve image quality in breast MRI, to simplify the clinical workflow, shorten measurement time, and achieve consistency in breast shape with other procedures such as ultrasound, surgery, and radiation therapy. MATERIALS AND METHODS To this end, we propose "panoramic breast MRI"-an approach combining a wearable radiofrequency coil for 3 T breast MRI (the "BraCoil"), acquisition in the supine position, and a panoramic visualization of the images. We demonstrate the potential of panoramic breast MRI in a pilot study on 12 healthy volunteers and 1 patient, and compare it to the state of the art. RESULTS With the BraCoil, we demonstrate up to 3-fold signal-to-noise ratio compared with clinical standard coils and acceleration factors up to 6 × 4. Panoramic visualization of supine breast images reduces the number of slices to be viewed by a factor of 2-4. CONCLUSIONS Panoramic breast MRI allows for high-quality diagnostic imaging and facilitated correlation to other diagnostic and interventional procedures. The developed wearable radiofrequency coil in combination with dedicated image processing has the potential to improve patient comfort while enabling more time-efficient breast MRI compared with clinical coils.
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Chai S, Yan X. Miniature and flexible Bazooka balun for high-field MRI. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 356:107577. [PMID: 37897924 PMCID: PMC10842505 DOI: 10.1016/j.jmr.2023.107577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 10/10/2023] [Accepted: 10/23/2023] [Indexed: 10/30/2023]
Abstract
Flexible coils offer improved patient comfort and better imaging quality. However, rigid and bulky baluns in RF coils limit flexibility and manufacturing. A miniaturized and flexible balun design was proposed to address this issue. It replaced rigid components with an ultra-flexible rubber tube and a flexible coaxial capacitor. Simulations validated the concept, and bench tests confirmed its performance, including a measured common-mode rejection ratio of -15.8 dB. The flexible balun was integrated into a 4-channel coil array, evaluating impedance changes caused by the "hand effect." Compared to coils without the balun, the flexible coil with the proposed balun showed improved robustness in impedance matching and inter-element couplings. Transmit efficiency of the flexible coil with the balun was compared to coils without a balun and with a rigid, shielded cable trap. Results demonstrated that the proposed balun circuit maintained high transmit efficiency. Overall, the flexible balun design offers a promising solution for improving the flexibility and performance of RF coil arrays in MRI applications.
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Affiliation(s)
- Shuyang Chai
- Department of Electrical and Computer Engineering, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Xinqiang Yan
- Department of Electrical and Computer Engineering, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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Payne K, Zhao Y, Bhosale AA, Zhang X. Dual-tuned Coaxial-transmission-line RF coils for Hyperpolarized 13C and Deuterium 2H Metabolic MRS Imaging at Ultrahigh Fields. ARXIV 2023:arXiv:2307.11221v3. [PMID: 37502626 PMCID: PMC10370217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Objective Information on the metabolism of tissues in healthy and diseased states plays a significant role in the detection and understanding of tumors, neurodegenerative diseases, diabetes, and other metabolic disorders. Hyperpolarized carbon-13 magnetic resonance imaging (13C-HPMRI) and deuterium metabolic imaging (2H-DMI) are two emerging X-nuclei used as practical imaging tools to investigate tissue metabolism. However due to their low gyromagnetic ratios (ɣ13C = 10.7 MHz/T; ɣ 2H = 6.5 MHz/T) and natural abundance, such method required a sophisticated dual-tuned radiofrequency (RF) coil. Methods Here, we report a dual-tuned coaxial transmission line (CTL) RF coil agile for metabolite information operating at 7T with independent tuning capability. The design analysis has demonstrated how both resonant frequencies can be individually controlled by simply varying the constituent of the design parameters. Results Numerical results have demonstrated a broadband tuning range capability, covering most of the X-nucleus signal, especially the 13C and 2H spectra at 7T. Furthermore, in order to validate the feasibility of the proposed design, both dual-tuned 1H/13C and 1H/2H CTLs RF coils are fabricated using a semi-flexible RG-405 .086" coaxial cable and bench test results (scattering parameters and magnetic field efficiency/distribution) are successfully obtained. Conclusion The proposed dual-tuned RF coils reveal highly effective magnetic field obtained from both proton and heteronuclear signal which is crucial for accurate and detailed imaging. Significance The successful development of this new dual-tuned RF coil technique would provide a tangible and efficient tool for ultrahigh field metabolic MR imaging.
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Affiliation(s)
- Komlan Payne
- Department of Biomedical Engineering, State University of New York at Buffalo, Buffalo, NY 14260 USA
| | - Yunkun Zhao
- Department of Biomedical Engineering, State University of New York at Buffalo, Buffalo, NY 14260 USA
| | - Aditya Ashok Bhosale
- Department of Biomedical Engineering, State University of New York at Buffalo, Buffalo, NY 14260 USA
| | - Xiaoliang Zhang
- Departments of Biomedical Engineering and Electrical Engineering, State University of New York at Buffalo, Buffalo, NY 14260 USA
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Abel F, Tan ET, Lunenburg M, van Leeuwen C, van Hooren T, van Uden M, Arteaga C, Vincent J, Robb F, Sneag DB. Flexible array coil for cervical and extraspinal (FACE) MRI at 3.0 Tesla. Phys Med Biol 2023; 68:215011. [PMID: 37816375 DOI: 10.1088/1361-6560/ad0217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Accepted: 10/10/2023] [Indexed: 10/12/2023]
Abstract
Objective.High-resolution MRI of the cervical spine (c-spine) and extraspinal neck region requires close-fitting receiver coils to maximize the signal-to-noise ratio (SNR). Conventional, rigid C-spine receiver coils do not adequately contour to the neck to accommodate varying body shapes, resulting in suboptimal SNR. Recent innovations in flexible surface coil array designs may provide three-dimensional (3D) bendability and conformability to optimize SNR, while improving capabilities for higher acceleration factors.Approach.This work describes the design, implementation, and preliminaryin vivotesting of a novel, conformal 23-channel receive-only flexible array for cervical and extraspinal (FACE) MRI at 3-Tesla (T), with use of high-impedance elements to enhance the coil's flexibility. Coil performance was tested by assessing SNR and geometry factors (g-factors) in a phantom compared to a conventional 21-channel head-neck-unit (HNU).In vivoimaging was performed in healthy human volunteers and patients using high-resolution c-spine and neck MRI protocols at 3T, including MR neurography (MRN).Main results.Mean SNR with the FACE was 141%-161% higher at left, right, and posterior off-isocenter positions and 4% higher at the isocenter of the phantom compared to the HNU. Parallel imaging performance was comparable for an acceleration factor (R) = 2 × 2 between the two coils, but improved forR= 3 × 3 with meang-factors ranging from 1.46-2.15 with the FACE compared to 2.36-3.62 obtained with the HNU. Preliminary human volunteer and patient testing confirmed that equivalent or superior image quality could be obtained for evaluation of osseous and soft tissue structures of the cervical region with the FACE.Significance.A conformal and highly flexible cervical array with high-impedance coil elements can potentially enable higher-resolution imaging for cervical imaging.
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Affiliation(s)
- Frederik Abel
- Hospital for Special Surgery, 535 East 70th Street, NY 10021, United States of America
| | - Ek T Tan
- Hospital for Special Surgery, 535 East 70th Street, NY 10021, United States of America
| | - Martijn Lunenburg
- Tesla Dynamic Coils, Schimminck 12, 5301 Zaltbommel, The Netherlands
| | - Carel van Leeuwen
- Tesla Dynamic Coils, Schimminck 12, 5301 Zaltbommel, The Netherlands
| | - Thijs van Hooren
- Tesla Dynamic Coils, Schimminck 12, 5301 Zaltbommel, The Netherlands
| | - Mark van Uden
- Tesla Dynamic Coils, Schimminck 12, 5301 Zaltbommel, The Netherlands
| | - Catalina Arteaga
- Tesla Dynamic Coils, Schimminck 12, 5301 Zaltbommel, The Netherlands
| | - Jana Vincent
- GE HealthCare, 1515 Danner Dr, 44202 Aurora, OH, United States of America
| | - Fraser Robb
- GE HealthCare, 1515 Danner Dr, 44202 Aurora, OH, United States of America
| | - Darryl B Sneag
- Hospital for Special Surgery, 535 East 70th Street, NY 10021, United States of America
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Motovilova E, Ching T, Vincent J, Shin J, Tan ET, Taracila V, Robb F, Hashimoto M, Sneag DB, Winkler SA. Dual-Channel Stretchable, Self-Tuning, Liquid Metal Coils and Their Fabrication Techniques. SENSORS (BASEL, SWITZERLAND) 2023; 23:7588. [PMID: 37688046 PMCID: PMC10490642 DOI: 10.3390/s23177588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 08/28/2023] [Accepted: 08/29/2023] [Indexed: 09/10/2023]
Abstract
Flexible and stretchable radiofrequency coils for magnetic resonance imaging represent an emerging and rapidly growing field. The main advantage of such coil designs is their conformal nature, enabling a closer anatomical fit, patient comfort, and freedom of movement. Previously, we demonstrated a proof-of-concept single element stretchable coil design with a self-tuning smart geometry. In this work, we evaluate the feasibility of scaling this coil concept to a multi-element coil array and the associated engineering and manufacturing challenges. To this goal, we study a dual-channel coil array using full-wave simulations, bench testing, in vitro, and in vivo imaging in a 3 T scanner. We use three fabrication techniques to manufacture dual-channel receive coil arrays: (1) single-layer casting, (2) double-layer casting, and (3) direct-ink-writing. All fabricated arrays perform equally well on the bench and produce similar sensitivity maps. The direct-ink-writing method is found to be the most advantageous fabrication technique for fabrication speed, accuracy, repeatability, and total coil array thickness (0.6 mm). Bench tests show excellent frequency stability of 128 ± 0.6 MHz (0% to 30% stretch). Compared to a commercial knee coil array, the stretchable coil array is more conformal to anatomy and provides 50% improved signal-to-noise ratio in the region of interest.
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Affiliation(s)
- Elizaveta Motovilova
- Department of Radiology, Weill Cornell Medicine, New York, NY 10065, USA
- Department of Radiology and Imaging, Hospital for Special Surgery, New York, NY 10021, USA
| | - Terry Ching
- Pillar of Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore
- Digital Manufacturing and Design (DManD) Centre, Singapore University of Technology and Design, Singapore 487372, Singapore
- Department of Biomedical Engineering, National University of Singapore, Singapore 117583, Singapore
| | | | - James Shin
- Department of Radiology, Weill Cornell Medicine, New York, NY 10065, USA
| | - Ek Tsoon Tan
- Department of Radiology and Imaging, Hospital for Special Surgery, New York, NY 10021, USA
| | | | | | - Michinao Hashimoto
- Pillar of Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore
- Digital Manufacturing and Design (DManD) Centre, Singapore University of Technology and Design, Singapore 487372, Singapore
| | - Darryl B. Sneag
- Department of Radiology and Imaging, Hospital for Special Surgery, New York, NY 10021, USA
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20
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Woo MK, DelaBarre L, Waks M, Lagore R, Kim J, Jungst S, Eryaman Y, Ugurbil K, Adriany G. A 32-Channel Sleeve Antenna Receiver Array for Human Head MRI Applications at 10.5 T. IEEE TRANSACTIONS ON MEDICAL IMAGING 2023; 42:2643-2652. [PMID: 37030782 DOI: 10.1109/tmi.2023.3261922] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
For human brain magnetic resonance imaging (MRI), high channel count ( ≥ 32 ) radiofrequency receiver coil arrays are utilized to achieve maximum signal-to-noise ratio (SNR) and to accelerate parallel imaging techniques. With ultra-high field (UHF) MRI at 7 tesla (T) and higher, dipole antenna arrays have been shown to generate high SNR in the deep regions of the brain, however the array elements exhibit increased electromagnetic coupling with one another, making array construction more difficult with the increasing number of elements. Compared to a classical dipole antenna array, a sleeve antenna array incorporates the coaxial ground into the feed-point, resulting in a modified asymmetric antenna structure with improved intra-element decoupling. Here, we extended our previous 16-channel sleeve transceiver work and developed a 32-channel azimuthally arranged sleeve antenna receive-only array for 10.5 T human brain imaging. We experimentally compared the achievable SNR of the sleeve antenna array at 10.5 T to a more traditional 32-channel loop array bult onto a human head-shaped former. The results obtained with a head shaped phantom clearly demonstrated that peripheral intrinsic SNR can be significantly improved compared to a loop array with the same number of elements- except for the superior part of the phantom where sleeve antenna elements are not located.
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21
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Wang B, Walczyk J, Ahmed M, Elkowitz S, Daniels S, Brown R, Burke CJ. Extended and weightbearing wrist 3-T MRI using a novel harness and flexible 24-channel glove coil to evaluate carpal kinematics: a pilot study in 10 volunteers. Acta Radiol 2023; 64:2570-2577. [PMID: 37470466 DOI: 10.1177/02841851231188222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/21/2023]
Abstract
BACKGROUND Wrist pain in the extended or extended weightbearing positions may be incompletely evaluated using standard magnetic resonance imaging (MRI) with standard rigid clamshell coils in the neutral position. PURPOSE To evaluate a flexible 24-channel glove coil and harness when imaging the wrist in neutral, dorsally extended, and weightbearing positions. MATERIAL AND METHODS Ten wrists in 10 asymptomatic volunteers (mean age = 29 years) were scanned. Participants underwent 3-T MRI using the harness and flexible glove coil, acquiring sagittal turbo spin echo (TSE) and half-Fourier acquisition single-shot turbo spin echo (HASTE) pulse sequences. Static TSE images were obtained in neutral, extended, and weightbearing positions using proton density parameters and independently evaluated by two radiologists for: dorsal radiocarpal ligament thickness; radiocapitate, radiolunate, and capitatolunate angles; palmar translation of the lunate on the radius; angulation of the extensor tendons; and distance from the distal extensor retinaculum to Lister's tubercle. Cine HASTE images were dynamically acquired between neutral-maximum extension to measure the radiocapitate angle. RESULTS Good reader agreement was observed (r > 0.73) for all measurements except palmar translation in the neutral position (r = 0.27). Significant increases in dorsal radiocarpal ligament thickness; radiocapitate, radiolunate and capitolunate angulation; and extensor tendon angulation were observed between the neutral and extended positions (P < 0.001). A further significant increase in these metrics between extended and weightbearing positions was also seen (P < 0.01). CONCLUSION Significant increases in dorsal radiocarpal ligament thickness, articular and tendon angulations occur during wrist extension, that further increase with dorsal weightbearing.
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Affiliation(s)
- Bili Wang
- Department of Radiology, New York University Langone Medical Center, New York, NY, USA
- Center for Advanced Imaging Innovation and Research, New York University Grossman School of Medicine, New York, NY, USA
| | - Jerzy Walczyk
- Department of Radiology, New York University Langone Medical Center, New York, NY, USA
- Center for Advanced Imaging Innovation and Research, New York University Grossman School of Medicine, New York, NY, USA
| | - Mohammad Ahmed
- Department of Radiology, New York University Langone Medical Center, New York, NY, USA
| | - Stuart Elkowitz
- Department of Orthopedic Surgery, New York University Grossman School of Medicine, New York, NY, USA
| | - Steven Daniels
- Department of Radiology, New York University Langone Medical Center, New York, NY, USA
| | - Ryan Brown
- Department of Radiology, New York University Langone Medical Center, New York, NY, USA
- Center for Advanced Imaging Innovation and Research, New York University Grossman School of Medicine, New York, NY, USA
| | - Christopher J Burke
- Department of Radiology, New York University Langone Medical Center, New York, NY, USA
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Sneag DB, Abel F, Potter HG, Fritz J, Koff MF, Chung CB, Pedoia V, Tan ET. MRI Advancements in Musculoskeletal Clinical and Research Practice. Radiology 2023; 308:e230531. [PMID: 37581501 PMCID: PMC10477516 DOI: 10.1148/radiol.230531] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 06/01/2023] [Accepted: 06/07/2023] [Indexed: 08/16/2023]
Abstract
Over the past decades, MRI has become increasingly important for diagnosing and longitudinally monitoring musculoskeletal disorders, with ongoing hardware and software improvements aiming to optimize image quality and speed. However, surging demand for musculoskeletal MRI and increased interest to provide more personalized care will necessitate a stronger emphasis on efficiency and specificity. Ongoing hardware developments include more powerful gradients, improvements in wide-bore magnet designs to maintain field homogeneity, and high-channel phased-array coils. There is also interest in low-field-strength magnets with inherently lower magnetic footprints and operational costs to accommodate global demand in middle- and low-income countries. Previous approaches to decrease acquisition times by means of conventional acceleration techniques (eg, parallel imaging or compressed sensing) are now largely overshadowed by deep learning reconstruction algorithms. It is expected that greater emphasis will be placed on improving synthetic MRI and MR fingerprinting approaches to shorten overall acquisition times while also addressing the demand of personalized care by simultaneously capturing microstructural information to provide greater detail of disease severity. Authors also anticipate increased research emphasis on metal artifact reduction techniques, bone imaging, and MR neurography to meet clinical needs.
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Affiliation(s)
- Darryl B. Sneag
- From the Department of Radiology and Imaging, Hospital for Special
Surgery, 535 E 70th St, New York, NY 10021 (D.B.S., F.A., H.G.P., M.F.K.,
E.T.T.); Department of Radiology, New York University Grossman School of
Medicine, New York, NY (J.F.); Department of Radiology, University of California
San Diego, La Jolla, Calif (C.B.C.); Radiology Service, Veterans Affairs San
Diego Healthcare System, La Jolla, Calif (C.B.C.); and Department of Radiology
and Biomedical Imaging, University of California San Francisco, San Francisco,
Calif (V.P.)
| | - Frederik Abel
- From the Department of Radiology and Imaging, Hospital for Special
Surgery, 535 E 70th St, New York, NY 10021 (D.B.S., F.A., H.G.P., M.F.K.,
E.T.T.); Department of Radiology, New York University Grossman School of
Medicine, New York, NY (J.F.); Department of Radiology, University of California
San Diego, La Jolla, Calif (C.B.C.); Radiology Service, Veterans Affairs San
Diego Healthcare System, La Jolla, Calif (C.B.C.); and Department of Radiology
and Biomedical Imaging, University of California San Francisco, San Francisco,
Calif (V.P.)
| | - Hollis G. Potter
- From the Department of Radiology and Imaging, Hospital for Special
Surgery, 535 E 70th St, New York, NY 10021 (D.B.S., F.A., H.G.P., M.F.K.,
E.T.T.); Department of Radiology, New York University Grossman School of
Medicine, New York, NY (J.F.); Department of Radiology, University of California
San Diego, La Jolla, Calif (C.B.C.); Radiology Service, Veterans Affairs San
Diego Healthcare System, La Jolla, Calif (C.B.C.); and Department of Radiology
and Biomedical Imaging, University of California San Francisco, San Francisco,
Calif (V.P.)
| | - Jan Fritz
- From the Department of Radiology and Imaging, Hospital for Special
Surgery, 535 E 70th St, New York, NY 10021 (D.B.S., F.A., H.G.P., M.F.K.,
E.T.T.); Department of Radiology, New York University Grossman School of
Medicine, New York, NY (J.F.); Department of Radiology, University of California
San Diego, La Jolla, Calif (C.B.C.); Radiology Service, Veterans Affairs San
Diego Healthcare System, La Jolla, Calif (C.B.C.); and Department of Radiology
and Biomedical Imaging, University of California San Francisco, San Francisco,
Calif (V.P.)
| | - Matthew F. Koff
- From the Department of Radiology and Imaging, Hospital for Special
Surgery, 535 E 70th St, New York, NY 10021 (D.B.S., F.A., H.G.P., M.F.K.,
E.T.T.); Department of Radiology, New York University Grossman School of
Medicine, New York, NY (J.F.); Department of Radiology, University of California
San Diego, La Jolla, Calif (C.B.C.); Radiology Service, Veterans Affairs San
Diego Healthcare System, La Jolla, Calif (C.B.C.); and Department of Radiology
and Biomedical Imaging, University of California San Francisco, San Francisco,
Calif (V.P.)
| | - Christine B. Chung
- From the Department of Radiology and Imaging, Hospital for Special
Surgery, 535 E 70th St, New York, NY 10021 (D.B.S., F.A., H.G.P., M.F.K.,
E.T.T.); Department of Radiology, New York University Grossman School of
Medicine, New York, NY (J.F.); Department of Radiology, University of California
San Diego, La Jolla, Calif (C.B.C.); Radiology Service, Veterans Affairs San
Diego Healthcare System, La Jolla, Calif (C.B.C.); and Department of Radiology
and Biomedical Imaging, University of California San Francisco, San Francisco,
Calif (V.P.)
| | - Valentina Pedoia
- From the Department of Radiology and Imaging, Hospital for Special
Surgery, 535 E 70th St, New York, NY 10021 (D.B.S., F.A., H.G.P., M.F.K.,
E.T.T.); Department of Radiology, New York University Grossman School of
Medicine, New York, NY (J.F.); Department of Radiology, University of California
San Diego, La Jolla, Calif (C.B.C.); Radiology Service, Veterans Affairs San
Diego Healthcare System, La Jolla, Calif (C.B.C.); and Department of Radiology
and Biomedical Imaging, University of California San Francisco, San Francisco,
Calif (V.P.)
| | - Ek T. Tan
- From the Department of Radiology and Imaging, Hospital for Special
Surgery, 535 E 70th St, New York, NY 10021 (D.B.S., F.A., H.G.P., M.F.K.,
E.T.T.); Department of Radiology, New York University Grossman School of
Medicine, New York, NY (J.F.); Department of Radiology, University of California
San Diego, La Jolla, Calif (C.B.C.); Radiology Service, Veterans Affairs San
Diego Healthcare System, La Jolla, Calif (C.B.C.); and Department of Radiology
and Biomedical Imaging, University of California San Francisco, San Francisco,
Calif (V.P.)
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Lou F, Tang X, Quan Z, Qian M, Wang J, Qu S, Gao Y, Wang Y, Pan G, Lai HY, Roe AW, Zhang X. A 16-channel loop array for in vivo macaque whole-brain imaging at 7 T. Magn Reson Imaging 2023:S0730-725X(23)00110-8. [PMID: 37356599 DOI: 10.1016/j.mri.2023.06.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 06/20/2023] [Accepted: 06/22/2023] [Indexed: 06/27/2023]
Abstract
Combining multimodal approaches with functional magnetic resonance imaging (fMRI) has catapulted the research on brain circuitries of non-human primates (NHPs) into a new era. However, many studies are constrained by a lack of appropriate RF coils. In this study,a single loop transmit and 16-channel receive array coil was constructed for brain imaging of macaques at 7 Tesla (7 T). The 16 receive channels were mounted on a 3D-printed helmet-shaped form closely fiting the macaque head, with fourteen openings arranged for multimodal devices around the cortical regions. Coil performance was evaluated by quantifying and comparing signal-to-noise ratio (SNR) maps, noise correlations, g-factor maps and flip-angle maps with a 28-channel commercial knee coil. The in vivo results suggested that the macaque coil has higher SNR in cortical regions and better acceleration ability in parallel imaging, which may benefit revealing mesoscale organizations in the brain.
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Affiliation(s)
- Feiyang Lou
- The Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China; MOE Frontier Science Center for Brain Science and Brain-machine Integration, Zhejiang University, Hangzhou, China
| | - Xiaocui Tang
- The Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China; MOE Frontier Science Center for Brain Science and Brain-machine Integration, Zhejiang University, Hangzhou, China
| | - Zhiyan Quan
- The Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China; MOE Frontier Science Center for Brain Science and Brain-machine Integration, Zhejiang University, Hangzhou, China; Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China
| | - Meizhen Qian
- The Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China; MOE Frontier Science Center for Brain Science and Brain-machine Integration, Zhejiang University, Hangzhou, China; Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Jianbao Wang
- The Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China; MOE Frontier Science Center for Brain Science and Brain-machine Integration, Zhejiang University, Hangzhou, China
| | - Shuxian Qu
- The Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China; MOE Frontier Science Center for Brain Science and Brain-machine Integration, Zhejiang University, Hangzhou, China; Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China
| | - Yang Gao
- The Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China; MOE Frontier Science Center for Brain Science and Brain-machine Integration, Zhejiang University, Hangzhou, China; Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China
| | - Yueming Wang
- Qiushi Academy for Advanced Studies, Zhejiang University, Hangzhou, China; State Key Lab of CAD&CG, Zhejiang University, Hangzhou, China
| | - Gang Pan
- The State Key Lab of Brain-Machine Intelligence, Zhejiang University, Hangzhou, China; College of Computer Science and Technology, Zhejiang University, Hangzhou, China
| | - Hsin-Yi Lai
- The Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China; MOE Frontier Science Center for Brain Science and Brain-machine Integration, Zhejiang University, Hangzhou, China; Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China; Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Anna Wang Roe
- The Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China; MOE Frontier Science Center for Brain Science and Brain-machine Integration, Zhejiang University, Hangzhou, China; Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China; Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaotong Zhang
- The Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China; MOE Frontier Science Center for Brain Science and Brain-machine Integration, Zhejiang University, Hangzhou, China; Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China; Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China; College of Electrical Engineering, Zhejiang University, Hangzhou, China.
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Payne K, Bhosale AA, Zhao Y, Zhang X. Design of dual-band Coaxial-transmission-line coils with independent tuning capabilities. PROCEEDINGS OF THE INTERNATIONAL SOCIETY FOR MAGNETIC RESONANCE IN MEDICINE ... SCIENTIFIC MEETING AND EXHIBITION. INTERNATIONAL SOCIETY FOR MAGNETIC RESONANCE IN MEDICINE. SCIENTIFIC MEETING AND EXHIBITION 2023; 31:4080. [PMID: 37600528 PMCID: PMC10440074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 08/22/2023]
Affiliation(s)
- Komlan Payne
- Department of Biomedical Engineering, University at Buffalo, Buffalo, NY, United States
| | - Aditya A Bhosale
- Department of Biomedical Engineering, University at Buffalo, Buffalo, NY, United States
| | - Yunkun Zhao
- Department of Biomedical Engineering, University at Buffalo, Buffalo, NY, United States
| | - Xiaoliang Zhang
- Department of Biomedical Engineering, University at Buffalo, Buffalo, NY, United States
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Du F, Li N, Yang X, Zhang B, Zhang X, Li Y. Design and construction of an 8-channel transceiver coil array for rat imaging at 9.4 T. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 351:107302. [PMID: 37116433 DOI: 10.1016/j.jmr.2022.107302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 08/27/2022] [Accepted: 09/11/2022] [Indexed: 05/29/2023]
Abstract
Ultra-high field (UHF) small animal magnetic resonance imaging (MRI) is a crucial tool permitting investigation of metabolic diseases and identification of imaging biomarkers suitable for clinical diagnosis and translation. Radiofrequency (RF) coils are critical components in enabling acquisition of high-quality rat abdomen MRI data. However, efficient RF coils with high-channel count, capable of sensitive and accelerated rat abdomen imaging at 9.4 T, are not available commercially. The SNR of the commonly-used 9.4 T birdcage coil is relatively weak, particularly in the peripheral area of the subject. In addition, the birdcage is not readily to perform parallel imaging due to unavailability of the required multiple channels. Consequently, the extended scanning duration may cause unnecessary hazards to the rat. In this work, an 8-channel transceiver coil array was designed and constructed to provide good image quality and large coverage for rat abdomen imaging at 9.4 T. The structure and the performance of the developed array was optimized and evaluated by numerical electromagnetic simulations and bench tests, respectively. The MR imaging experiments in phantoms and rat models were also performed on a Bruker 9.4 T preclinical MRI system to validate the feasibility of the proposed design. The coil array supports a one-dimensional acceleration factor up to R = 4, providing good parallel imaging capabilities. These results demonstrated that the proposed 8-channel transceiver coil array for rat imaging has the ability to obtain high spatial resolution of rat abdomen anatomical structure images at 9.4 T.
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Affiliation(s)
- Feng Du
- Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China; Key Laboratory for Magnetic Resonance and Multimodality Imaging of Guangdong Province, Shenzhen 518055, Guang Dong, China
| | - Nan Li
- Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China; Key Laboratory for Magnetic Resonance and Multimodality Imaging of Guangdong Province, Shenzhen 518055, Guang Dong, China
| | - Xing Yang
- Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China; Key Laboratory for Magnetic Resonance and Multimodality Imaging of Guangdong Province, Shenzhen 518055, Guang Dong, China
| | - Baogui Zhang
- State Key Laboratory of Brain and Cognitive Sciences, Beijing MRI Center for Brain Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China; Brainnetome Center, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China
| | - Xiaoliang Zhang
- Department of Biomedical Engineering, State University of New York at Buffalo, NY, United States., Buffalo, NY, United States
| | - Ye Li
- Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China; Key Laboratory for Magnetic Resonance and Multimodality Imaging of Guangdong Province, Shenzhen 518055, Guang Dong, China.
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26
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Nohava L, Obermann M, Frass-Kriegl R, Soanca O, Laistler E. A modular system of flexible receive-only coil arrays for 3 T Magnetic Resonance Imaging. Z Med Phys 2023:S0939-3889(23)00070-3. [PMID: 37258388 DOI: 10.1016/j.zemedi.2023.05.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 04/18/2023] [Accepted: 05/08/2023] [Indexed: 06/02/2023]
Abstract
Flexible form-fitting radiofrequency coils provide high signal-to-noise ratio (SNR) for magnetic resonance imaging (MRI), and in array configuration large anatomical areas of interest can be covered. We propose a modular system - "ModFlex"- of flexible lightweight 4-channel coaxial coil arrays for 3 T MRI. We investigated the performance difference between commercial reference coils and 8- and 16-channel ModFlex receive-only array systems. In vivo, six anatomical targets in four regions of interest - the neck, the ankle, the spine and the hip - were imaged with the novel coil array system. The versatility of ModFlex and the robustness of the coil characteristics for different use cases is demonstrated. We measured an SNR gain for 4 out of 6 and similar SNR for 2 out of 6 anatomical target regions as compared to commercial reference coils. Parallel imaging capabilities are comparable to standard coils in hip and neck imaging, but ModFlex outperforms standard coils in ankle and spine imaging. High SNR combined with high acceleration possibilities enables faster imaging workflows and/or high-resolution MR acquisitions. The coil's versatility is beneficial for use cases with varying subject sizes and could improve patient comfort.
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Affiliation(s)
- Lena Nohava
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.
| | - Michael Obermann
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.
| | - Roberta Frass-Kriegl
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.
| | - Onisim Soanca
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.
| | - Elmar Laistler
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.
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27
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Gopalan K, Maravilla J, Mendelsohn J, Arias AC, Lustig M. Vacuum formed coils for MRI. Magn Reson Med 2023; 89:1684-1696. [PMID: 36479713 DOI: 10.1002/mrm.29546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 10/23/2022] [Accepted: 11/16/2022] [Indexed: 12/12/2022]
Abstract
PURPOSE To describe a digital fabrication method used for custom MRI receive coils with vacuum forming and electroless copper plating. METHODS Our process produces intricate copper traces on curved surfaces. A three-dimensional scan of a desired anatomy is obtained and used to design coil elements. The layout is predistorted with a self built simulation of the vacuum forming process and the geometric overlaps are tested with electromagnetic simulation software. The desired coil geometry is patterned onto a polycarbonate sheet by sandblasting through a tape mask. The sandblasted areas are then catalyzed with a palladium-tin solution and vacuum formed. The catalyzed, three-dimensional part is placed into a custom built plating tank and copper plated. Electronic components are attached to the copper traces to form resonant receive coils. The methods described here are demonstrated and tested with an 8 channel visual cortex coil array. RESULTS The prototype coils exhibit quality factor ratios higher than three, indicating body noise dominance. The coil array shows high signal-to-noise ratio (SNR) near the periphery of a head shaped phantom. In vivo images with up to 0 . 37 × 0 . 37 × 0 . 67 mm 3 $$ 0.37\times 0.37\times 0.67\;{\mathrm{mm}}^3 $$ spatial resolution were acquired on a human volunteer. CONCLUSION This work presents the first example of vacuum formed coils with direct electroless copper plating. Our fabrication method results in coil arrays that are in close proximity to the body. This methods described here may enable the rapid development of a set of coils of different sizes for applications including longitudinal fMRI studies and MR-guided therapies.
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Affiliation(s)
- Karthik Gopalan
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California, USA
| | - Julian Maravilla
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California, USA
| | - Jaren Mendelsohn
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California, USA
| | - Ana C Arias
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California, USA
| | - Michael Lustig
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California, USA
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28
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Harrevelt SD, Roos THM, Klomp DWJ, Steensma BR, Raaijmakers AJE. Simulation-based evaluation of SAR and flip angle homogeneity for five transmit head arrays at 14 T. MAGMA (NEW YORK, N.Y.) 2023; 36:245-255. [PMID: 37000320 PMCID: PMC10140109 DOI: 10.1007/s10334-023-01067-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 01/13/2023] [Accepted: 01/31/2023] [Indexed: 04/01/2023]
Abstract
INTRODUCTION Various research sites are pursuing 14 T MRI systems. However, both local SAR and RF transmit field inhomogeneity will increase. The aim of this simulation study is to investigate the trade-offs between peak local SAR and flip angle uniformity for five transmit coil array designs at 14 T in comparison to 7 T. METHODS Investigated coil array designs are: 8 dipole antennas (8D), 16 dipole antennas (16D), 8 loop coils (8D), 16 loop coils (16L), 8 dipoles/8 loop coils (8D8L) and for reference 8 dipoles at 7 T. Both RF shimming and kT-points were investigated by plotting L-curves of peak SAR levels vs flip angle homogeneity. RESULTS For RF shimming, the 16L array performs best. For kT-points, superior flip angle homogeneity is achieved at the expense of more power deposition, and the dipole arrays outperform the loop coil arrays. DISCUSSION AND CONCLUSION For most arrays and regular imaging, the constraint on head SAR is reached before constraints on peak local SAR are violated. Furthermore, the different drive vectors in kT-points alleviate strong peaks in local SAR. Flip angle inhomogeneity can be alleviated by kT-points at the expense of larger power deposition. For kT-points, the dipole arrays seem to outperform loop coil arrays.
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Affiliation(s)
- Seb D Harrevelt
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.
| | - Thomas H M Roos
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Dennis W J Klomp
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Bart R Steensma
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Alexander J E Raaijmakers
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
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29
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Lebenatus A, Tesch K, Rudolph W, Naujokat H, Koktzoglou I, Edelman RR, Graessner J, Jansen O, Salehi Ravesh M. Evaluation of Lower Leg Arteries and Fibular Perforators before Microsurgical Fibular Transfer Using Noncontrast-Enhanced Quiescent-Interval Slice-Selective (QISS) Magnetic Resonance Angiography. J Clin Med 2023; 12:1634. [PMID: 36836170 PMCID: PMC9964888 DOI: 10.3390/jcm12041634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 02/11/2023] [Accepted: 02/16/2023] [Indexed: 02/22/2023] Open
Abstract
(1) Background: Preoperative imaging of the lower leg arteries is essential for planning fibular grafting. The aim of this study was to evaluate the feasibility and clinical value of non-contrast-enhanced (CE) Quiescent-Interval Slice-Selective (QISS)-magnetic resonance angiography (MRA) for reliably visualizing the anatomy and patency of the lower leg arteries and for preoperatively determining the presence, number, and location of fibular perforators. (2) Methods: The anatomy and stenoses of the lower leg arteries and the presence, number, and location of fibular perforators were determined in fifty patients with oral and maxillofacial tumors. Postoperative outcomes of patients after fibula grafting were correlated with preoperative imaging, demographic, and clinical parameters. (3) Results: A regular three-vessel supply was present in 87% of the 100 legs. QISS-MRA was able to accurately assign the branching pattern in patients with aberrant anatomy. Fibular perforators were found in 87% of legs. More than 94% of the lower leg arteries had no relevant stenoses. Fibular grafting was performed in 50% of patients with a 92% success rate. (4) Conclusions: QISS-MRA has the potential to be used as a preoperative non-CE MRA technique for the diagnosis and detection of anatomic variants of lower leg arteries and their pathologies, as well as for the assessment of fibular perforators.
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Affiliation(s)
- Annett Lebenatus
- Department of Radiology and Neuroradiology, University Hospital Schleswig-Holstein, Campus Kiel, 24105 Kiel, Germany
| | - Karolin Tesch
- Department of Radiology and Neuroradiology, University Hospital Schleswig-Holstein, Campus Kiel, 24105 Kiel, Germany
| | - Wiebke Rudolph
- Department of Radiology and Neuroradiology, University Hospital Schleswig-Holstein, Campus Kiel, 24105 Kiel, Germany
| | - Hendrik Naujokat
- Department of Oral and Maxillofacial Surgery, University Hospital Schleswig-Holstein, Campus Kiel, 24105 Kiel, Germany
| | - Ioannis Koktzoglou
- Department of Radiology, NorthShore University HealthSystem, Evanston, IL 60201, USA
- Pritzker School of Medicine, University of Chicago, Chicago, IL 60637, USA
| | - Robert R. Edelman
- Department of Radiology, NorthShore University HealthSystem, Evanston, IL 60201, USA
- Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | | | - Olav Jansen
- Department of Radiology and Neuroradiology, University Hospital Schleswig-Holstein, Campus Kiel, 24105 Kiel, Germany
| | - Mona Salehi Ravesh
- Department of Radiology and Neuroradiology, University Hospital Schleswig-Holstein, Campus Kiel, 24105 Kiel, Germany
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Abstract
ABSTRACT Magnetic resonance neurography of the brachial plexus (BP) is challenging owing to its complex anatomy and technical obstacles around this anatomic region. Magnetic resonance techniques to improve image quality center around increasing nerve-to-background contrast ratio and mitigating imaging artifacts. General considerations include unilateral imaging of the BP at 3.0 T, appropriate selection and placement of surface coils, and optimization of pulse sequences. Technical considerations to improve nerve conspicuity include fat, vascular, and respiratory artifact suppression techniques; metal artifact reduction techniques; and 3-dimensional sequences. Specific optimization of these techniques for BP magnetic resonance neurography greatly improves image quality and diagnostic confidence to help guide nonoperative and operative management.
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Payne K, Ying LL, Zhang X. Hairpin RF resonators for MR imaging transceiver arrays with high inter-channel isolation and B 1 efficiency at ultrahigh field 7 T. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2022; 345:107321. [PMID: 36335877 DOI: 10.1016/j.jmr.2022.107321] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 10/17/2022] [Accepted: 10/22/2022] [Indexed: 06/03/2023]
Abstract
Electromagnetic decoupling among a close-fitting or high-density transceiver RF array elements is required to maintain the integrity of the magnetic flux density from individual channel for enhanced performance in detection sensitivity and parallel imaging. High-impedance RF coils have demonstrated to be a prominent design method to circumvent these coupling issues. Yet, inherent characteristics of these coils have ramification on the B1 field efficiency and SNR. In this work, we propose a hairpin high impedance RF resonator design for highly decoupled multichannel transceiver arrays at ultrahigh magnetic fields. Due to the high impedance property of the hairpin resonators, the proposed transceiver array can provide high decoupling performance without using any dedicated decoupling circuit among the resonant elements. Because of elimination of lumped inductors in the resonator circuit, higher B1 field efficiency in imaging subjects can be expected. In order to validate the feasibility of the proposed hairpin RF coils, systematical studies on decoupling performance, field distribution, and SNR are performed, and the results are compared with those obtained from existing high-impedance RF coil, e.g., "self-decoupled RF coil". To further investigate its performance, an 8-channel head coil array using the proposed hairpin resonators loaded with a cylindrical phantom is designed, demonstrating a 19 % increase of the B1+ field intensity compared to the self-decoupled coils at 7 T. Furthermore, the characteristics of the hairpin RF coils are evaluated using a more realistic human head voxel model numerically. The proposed hairpin RF coil provides excellent decoupling performance and superior RF magnetic field efficiency compared to the "self-decoupled" high impedance coils. Bench test of a pair of fabricated hairpin coils prove to be in good accordance with numerical results.
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Affiliation(s)
- Komlan Payne
- Department of Biomedical Engineering, State University of New York at Buffalo, Buffalo, NY 14260, USA.
| | - Leslie L Ying
- Department of Biomedical Engineering, State University of New York at Buffalo, Buffalo, NY 14260, USA; Department of Electrical Engineering, State University of New York at Buffalo, Buffalo, NY 14260, USA.
| | - Xiaoliang Zhang
- Department of Biomedical Engineering, State University of New York at Buffalo, Buffalo, NY 14260, USA; Department of Electrical Engineering, State University of New York at Buffalo, Buffalo, NY 14260, USA.
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Wang B, Siddiq SS, Walczyk J, Bruno M, Khodarahmi I, Brinkmann IM, Rehner R, Lakshmanan K, Fritz J, Brown R. A flexible MRI coil based on a cable conductor and applied to knee imaging. Sci Rep 2022; 12:15010. [PMID: 36056131 PMCID: PMC9440226 DOI: 10.1038/s41598-022-19282-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 08/26/2022] [Indexed: 11/08/2022] Open
Abstract
Flexible radiofrequency coils for magnetic resonance imaging (MRI) have garnered attention in research and industrial communities because they provide improved accessibility and performance and can accommodate a range of anatomic postures. Most recent flexible coil developments involve customized conductors or substrate materials and/or target applications at 3 T or above. In contrast, we set out to design a flexible coil based on an off-the-shelf conductor that is suitable for operation at 0.55 T (23.55 MHz). Signal-to-noise ratio (SNR) degradation can occur in such an environment because the resistance of the coil conductor can be significant with respect to the sample. We found that resonating a commercially available RG-223 coaxial cable shield with a lumped capacitor while the inner conductor remained electrically floating gave rise to a highly effective "cable coil." A 10-cm diameter cable coil was flexible enough to wrap around the knee, an application that can benefit from flexible coils, and had similar conductor loss and SNR as a standard-of-reference rigid copper coil. A two-channel cable coil array also provided good SNR robustness against geometric variability, outperforming a two-channel coaxial coil array by 26 and 16% when the elements were overlapped by 20-40% or gapped by 30-50%, respectively. A 6-channel cable coil array was constructed for 0.55 T knee imaging. Incidental cartilage and bone pathologies were clearly delineated in T1- and T2-weighted turbo spin echo images acquired in 3-4 min with the proposed coil, suggesting that clinical quality knee imaging is feasible in an acceptable examination timeframe. Correcting for T1, the SNR measured with the cable coil was approximately threefold lower than that measured with a 1.5 T state-of-the-art 18-channel coil, which is expected given the threefold difference in main magnetic field strength. This result suggests that the 0.55 T cable coil conductor loss does not deleteriously impact SNR, which might be anticipated at low field.
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Affiliation(s)
- Bili Wang
- Department of Radiology, Center for Advanced Imaging Innovation and Research (CAI2R), New York University Grossman School of Medicine, 660 First Ave, New York, NY, USA
| | - Syed S Siddiq
- Department of Radiology, Center for Advanced Imaging Innovation and Research (CAI2R), New York University Grossman School of Medicine, 660 First Ave, New York, NY, USA
- Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Jerzy Walczyk
- Department of Radiology, Center for Advanced Imaging Innovation and Research (CAI2R), New York University Grossman School of Medicine, 660 First Ave, New York, NY, USA
| | - Mary Bruno
- Department of Radiology, Center for Advanced Imaging Innovation and Research (CAI2R), New York University Grossman School of Medicine, 660 First Ave, New York, NY, USA
| | - Iman Khodarahmi
- Department of Radiology, Center for Advanced Imaging Innovation and Research (CAI2R), New York University Grossman School of Medicine, 660 First Ave, New York, NY, USA
- Division of Musculoskeletal Radiology, Department of Radiology, New York University Grossman School of Medicine, New York, NY, USA
| | | | | | - Karthik Lakshmanan
- Department of Radiology, Center for Advanced Imaging Innovation and Research (CAI2R), New York University Grossman School of Medicine, 660 First Ave, New York, NY, USA
| | - Jan Fritz
- Department of Radiology, Center for Advanced Imaging Innovation and Research (CAI2R), New York University Grossman School of Medicine, 660 First Ave, New York, NY, USA
- Division of Musculoskeletal Radiology, Department of Radiology, New York University Grossman School of Medicine, New York, NY, USA
| | - Ryan Brown
- Department of Radiology, Center for Advanced Imaging Innovation and Research (CAI2R), New York University Grossman School of Medicine, 660 First Ave, New York, NY, USA.
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Sanchez‐Heredia JD, Olin RB, Grist JT, Wang W, Bøgh N, Zhurbenko V, Hansen ES, Schulte RF, Tyler D, Laustsen C, Ardenkjær‐Larsen JH. RF coil design for accurate parallel imaging on 13 C MRSI using 23 Na sensitivity profiles. Magn Reson Med 2022; 88:1391-1405. [PMID: 35635156 PMCID: PMC9328386 DOI: 10.1002/mrm.29259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 02/14/2022] [Accepted: 03/14/2022] [Indexed: 11/22/2022]
Abstract
PURPOSE To develop a coil-based method to obtain accurate sensitivity profiles in 13 C MRI at 3T from the endogenous 23 Na. An eight-channel array is designed for 13 C MR acquisitions. As application examples, the array is used for two-fold accelerated acquisitions of both hyperpolarized 13 C metabolic imaging of pig kidneys and the human brain. METHODS A flexible coil array was tuned optimally for 13 C at 3T (32.1 MHz), with the coil coupling coefficients matched to be nearly identical at the resonance frequency of 23 Na (33.8 MHz). This is done by enforcing a high decoupling (obtained through highly mismatched preamplifiers) and adjusting the coupling frequency response. The SNR performance is compared to reference coils. RESULTS The measured sensitivity profiles on a phantom showed high spatial similarity for 13 C and 23 Na resonances, with average noise correlation of 9 and 11%, respectively. For acceleration factors 2, 3, and 4, the obtained maximum g-factors were 1.0, 1.1, and 2.6, respectively. The 23 Na profiles obtained in vivo could be used successfully to perform two-fold acceleration of hyperpolarized 13 C 3D acquisitions of both pig kidneys and a healthy human brain. CONCLUSION A receive array has been developed in such a way that the 13 C sensitivity profiles could be accurately obtained from measurements at the 23 Na frequency. This technique facilitates accelerated acquisitions for hyperpolarized 13 C imaging. The SNR performance obtained at the 13 C frequency, compares well to other state-of-the-art coils for the same purpose, showing slightly better superficial and central SNR.
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Affiliation(s)
| | - Rie B. Olin
- Department of Health TechnologyTechnical University of DenmarkKgs. LyngbyDenmark
| | - James T. Grist
- Department of Physiology, Anatomy and GeneticsUniversity of OxfordOxfordUK
- Oxford Centre for Clinical Magnetic Resonance ResearchUniversity of OxfordOxfordUK
- Department of RadiologyOxford University Hospitals TrustOxfordUK
- Institute of Cancer and Genomic SciencesUniversity of BirminghamBirminghamUK
| | - Wenjun Wang
- National Space InstituteTechnical University of DenmarkKgs. LyngbyDenmark
| | - Nikolaj Bøgh
- MR Research Centre, Department of Clinical MedicineAarhus UniversityAarhusDenmark
| | - Vitaliy Zhurbenko
- National Space InstituteTechnical University of DenmarkKgs. LyngbyDenmark
| | - Esben S. Hansen
- MR Research Centre, Department of Clinical MedicineAarhus UniversityAarhusDenmark
| | | | - Damian Tyler
- Department of Physiology, Anatomy and GeneticsUniversity of OxfordOxfordUK
- Oxford Centre for Clinical Magnetic Resonance ResearchUniversity of OxfordOxfordUK
| | - Christoffer Laustsen
- MR Research Centre, Department of Clinical MedicineAarhus UniversityAarhusDenmark
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Zijlema SE, Breimer W, Gosselink MWJM, Bruijnen T, Arteaga de Castro CS, Tijssen RHN, Lagendijk JJW, Philippens MEP, van den Berg CAT. A mask-compatible, radiolucent, 8-channel head and neck receive array for MRI-guided radiotherapy treatments and pre-treatment simulation. Phys Med Biol 2022; 67. [DOI: 10.1088/1361-6560/ac6ebd] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 05/11/2022] [Indexed: 11/11/2022]
Abstract
Abstract
Immobilization masks are used to prevent patient movement during head and neck (H&N) radiotherapy. Motion restriction is beneficial both during treatment, as well as in the pre-treatment simulation phase, where magnetic resonance imaging (MRI) is often used for target definition. However, the shape and size of the immobilization masks hinder the use of regular, close-fitting MRI receive arrays. In this work, we developed a mask-compatible 8-channel H&N array that consists of a single-channel baseplate, on which the mask can be secured, and a flexible 7-channel anterior element that follows the shape of the mask. The latter uses high impedance coils to achieve its flexibility and radiolucency. A fully-functional prototype was manufactured, its radiolucency was characterized, and the gain in imaging performance with respect to current clinical setups was quantified. Dosimetry measurements showed an overall dose change of −0.3%. Small, local deviations were up to −2.7% but had no clinically significant impact on a full treatment plan, as gamma pass rates (3%/3 mm) only slightly reduced from 97.9% to 97.6% (clinical acceptance criterion: ≥95%). The proposed H&N array improved the imaging performance with respect to three clinical setups. The H&N array more than doubled (+123%) and tripled (+246%) the signal-to-noise ratio with respect to the clinical MRI-simulation and MR-linac setups, respectively. G-factors were also lower with the proposed H&N array. The improved imaging performance resulted in a clearly visible signal-to-noise ratio improvement of clinically used TSE and DWI acquisitions. In conclusion, the 8-channel H&N array improves the imaging performance of MRI-simulation and MR-linac acquisitions, while dosimetry suggests that no clinically significant dose changes are induced.
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Zhu Y, Sappo CR, Grissom WA, Gore JC, Yan X. Dual-Tuned Lattice Balun for Multi-Nuclear MRI and MRS. IEEE TRANSACTIONS ON MEDICAL IMAGING 2022; 41:1420-1430. [PMID: 34990352 PMCID: PMC9812758 DOI: 10.1109/tmi.2022.3140717] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Balun or trap circuits are critical components for suppressing common-mode currents flowing on the outer conductors of coaxial cables in RF coil systems for Magnetic Resonance Imaging (MRI) and Magnetic Resonance Spectroscopy (MRS). Common-mode currents affect coils' tuning and matching, induce losses, pick up extra noise from the surrounding environment, lead to undesired cross-talk, and cause safety concerns in animal and human imaging. First proposed for microwave antenna applications, the Lattice balun has been widely used in MRI coils. It has a small footprint and can be easily integrated with coil tuning/matching circuits. However, the Lattice balun is typically a single-tuned circuit and cannot be used for multi-nuclear MRI and MRS with two RF frequencies. This work describes a dual-tuned Lattice balun design that is suitable for multi-nuclear MRI/MRS. It was first analyzed theoretically to derive component values. RF circuit simulations were then performed to validate the theoretical analysis and provide guidance for practical construction. Based on the simulation results, a dual-tuned balun circuit was built for 7T 1H/23Na MRI and bench tested. The fabricated dual-tuned balun exhibits superior performance at the Larmor frequencies of both 1H and 23Na, with less than 0.15 dB insertion loss and better than 17 dB common-mode rejection ratio at both frequencies.
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Ohliger MA. Invited Commentary: MRI Radiofrequency Coils-Current Uses and Future Innovation. Radiographics 2022; 42:E100-E101. [PMID: 35394889 DOI: 10.1148/rg.210214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Michael A Ohliger
- From the Department of Radiology and Biomedical Imaging, University of California, San Francisco, Box 0628, 1001 Potrero Ave, SFGH 5, Room 1x60, San Francisco, CA 94143
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Zhang B, Wang B, Ho J, Hodono S, Burke C, Lattanzi R, Vester M, Rehner R, Sodickson D, Brown R, Cloos M. Twenty-four-channel high-impedance glove array for hand and wrist MRI at 3T. Magn Reson Med 2022; 87:2566-2575. [PMID: 34971464 PMCID: PMC8847333 DOI: 10.1002/mrm.29147] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 12/12/2021] [Accepted: 12/15/2021] [Indexed: 12/29/2022]
Abstract
PURPOSE To present a novel 3T 24-channel glove array that enables hand and wrist imaging in varying postures. METHODS The glove array consists of an inner glove holding the electronics and an outer glove protecting the components. The inner glove consists of four main structures: palm, fingers, wrist, and a flap that rolls over on top. Each structure was constructed out of three layers: a layer of electrostatic discharge flame-resistant fabric, a layer of scuba neoprene, and a layer of mesh fabric. Lightweight and flexible high impedance coil (HIC) elements were inserted into dedicated tubes sewn into the fabric. Coil elements were deliberately shortened to minimize the matching interface. Siemens Tim 4G technology was used to connect all 24 HIC elements to the scanner with only one plug. RESULTS The 24-channel glove array allows large motion of both wrist and hand while maintaining the SNR needed for high-resolution imaging. CONCLUSION In this work, a purpose-built 3T glove array that embeds 24 HIC elements is demonstrated for both hand and wrist imaging. The 24-channel glove array allows a great range of motion of both the wrist and hand while maintaining a high SNR and providing good theoretical acceleration performance, thus enabling hand and wrist imaging at different postures to extract kinematic information.
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Affiliation(s)
- Bei Zhang
- Center for Advanced Imaging Innovation and Research (CAIR) and Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University Grossman School of Medicine, New York, NY, USA
- Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX, USA
| | - Bili Wang
- Center for Advanced Imaging Innovation and Research (CAIR) and Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University Grossman School of Medicine, New York, NY, USA
| | - Justin Ho
- Center for Advanced Imaging Innovation and Research (CAIR) and Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University Grossman School of Medicine, New York, NY, USA
| | - Shota Hodono
- Centre for Advanced Imaging, Queensland University, Brisbane, Australia
| | | | - Riccardo Lattanzi
- Center for Advanced Imaging Innovation and Research (CAIR) and Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University Grossman School of Medicine, New York, NY, USA
- Vilcek Institute of Graduate Biomedical Sciences, New York University Grossman School of Medicine, New York, NY, USA
| | | | | | - Daniel Sodickson
- Center for Advanced Imaging Innovation and Research (CAIR) and Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University Grossman School of Medicine, New York, NY, USA
| | - Ryan Brown
- Center for Advanced Imaging Innovation and Research (CAIR) and Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University Grossman School of Medicine, New York, NY, USA
| | - Martijn Cloos
- Center for Advanced Imaging Innovation and Research (CAIR) and Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University Grossman School of Medicine, New York, NY, USA
- Centre for Advanced Imaging, Queensland University, Brisbane, Australia
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Darnell D, Truong TK, Song AW. Recent Advances in Radio-Frequency Coil Technologies: Flexible, Wireless, and Integrated Coil Arrays. J Magn Reson Imaging 2022; 55:1026-1042. [PMID: 34324753 PMCID: PMC10494287 DOI: 10.1002/jmri.27865] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 07/19/2021] [Accepted: 07/19/2021] [Indexed: 12/25/2022] Open
Abstract
Radio-frequency (RF) coils are to magnetic resonance imaging (MRI) scanners what eyes are to the human body. Because of their critical importance, there have been constant innovations driving the rapid development of RF coil technologies. Over the past four decades, the breadth and depth of the RF coil technology evolution have far exceeded the space allowed for this review article. However, these past developments have laid the very foundation on which some of the recent technical breakthroughs are built upon. Here, we narrow our focus on some of the most recent RF coil advances, specifically, on flexible, wireless, and integrated coil arrays. To provide a detailed review, we discuss the theoretical underpinnings, experimental implementations, promising results, as well as future outlooks covering these exciting topics. These recent innovations have greatly improved patient comfort and ease of scan, while also increasing the signal-to-noise ratio, image resolution, temporal throughput, and diagnostic and treatment accuracy. Together with advances in other MRI subfields, they will undoubtedly continue to drive the field forward and lead us to an ever more exciting future. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY: Stage 1.
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Affiliation(s)
- Dean Darnell
- Brain Imaging and Analysis Center, Duke University, Durham, North Carolina, USA
| | - Trong-Kha Truong
- Brain Imaging and Analysis Center, Duke University, Durham, North Carolina, USA
| | - Allen W. Song
- Brain Imaging and Analysis Center, Duke University, Durham, North Carolina, USA
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Fukui H, Onishi H, Nakamoto A, Wakayama T, Ota T, Tsuboyama T, Yano K, Tarewaki H, Koyama Y, Tatsumi M, Tomiyama N. Impact of Adaptive Image Receive Coil Technology for Liver MR Imaging at 3.0 Tesla: Intraindividual Comparison with use of Conventional Coil. Eur J Radiol 2022; 150:110271. [DOI: 10.1016/j.ejrad.2022.110271] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 02/22/2022] [Accepted: 03/17/2022] [Indexed: 11/03/2022]
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Okada T, Handa S, Ding B, Urayama SI, Fujimoto K, Shima A, Yoshii D, Ayaki T, Sawamoto N, Takahashi R, Onoe H, Isa T, Petropoulos L. Insertable inductively coupled volumetric coils for MR microscopy in a human 7T MR system. Magn Reson Med 2021; 87:1613-1620. [PMID: 34719801 PMCID: PMC9297907 DOI: 10.1002/mrm.29062] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 10/07/2021] [Accepted: 10/13/2021] [Indexed: 11/08/2022]
Abstract
PURPOSE To demonstrate the capability of insertable inductively coupled volumetric coils for MR microscopy in a human 7T MR system. METHODS Insertable inductively coupled volume coils with diameters of 26 and 64 mm (D26 and D64 coils) targeted for monkey and mouse brain specimen sizes were designed and fabricated. These coils were placed inside the imaging volume of a transmit/receive knee coil without wired connections to the main system. Signal-to-noise ratio (SNR) evaluations were conducted with and without the insertable coils, and the g-factor maps of parallel imaging (PI) were also calculated for the D64 coil. Brain specimens were imaged using 3D T 2 ∗ -weighted images with spatial resolution of isotropic 50 and 160 μm using D26 and D64 coils, respectively. RESULTS Relative average (SD) SNRs compared with knee coil alone were 12.54 (0.30) and 2.37 (0.05) at the center for the D26 and D64 coils, respectively. The mean g-factors of PI with the D64 coil for the factor of 2 were less than 1.1 in the left-right and anterior-posterior directions, and around 1.5 in the superior-inferior direction or when the PI factor of 3 was used. Acceleration in two directions showed lower g-factors but suffered from intrinsic low SNR. Representative T 2 ∗ -weighted images of the specimen showed structural details. CONCLUSION Inductively coupled small diameter coils insertable to the knee coil demonstrated high SNR and modest PI capability. The concept was successfully used to visualize fine structures of the brain specimen. The insertable coils are easy to handle and enable MR microscopy in a human whole-body 7T MRI system.
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Affiliation(s)
- Tomohisa Okada
- Human Brain Research Center, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Shinya Handa
- Quality Electrodynamics, Mayfield Village, Ohio, USA
| | - Bill Ding
- Quality Electrodynamics, Mayfield Village, Ohio, USA
| | - Shin-Ichi Urayama
- Human Brain Research Center, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Koji Fujimoto
- Human Brain Research Center, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Atsushi Shima
- Human Brain Research Center, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Daisuke Yoshii
- Department of Neurology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Takashi Ayaki
- Department of Neurology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Nobukatsu Sawamoto
- Department of Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Ryosuke Takahashi
- Department of Neurology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Hirotaka Onoe
- Human Brain Research Center, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Tadashi Isa
- Human Brain Research Center, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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van Leeuwen CC, Steensma BR, Klomp DWJ, van den Berg CAT, Raaijmakers AJE. The Coax Dipole: A fully flexible coaxial cable dipole antenna with flattened current distribution for body imaging at 7 Tesla. Magn Reson Med 2021; 87:528-540. [PMID: 34411327 PMCID: PMC9292881 DOI: 10.1002/mrm.28983] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 07/14/2021] [Accepted: 08/04/2021] [Indexed: 01/26/2023]
Abstract
Purpose The coax dipole antenna, a flexible antenna for body imaging at 7T is presented. Similar to the high impedance coil, this coaxial cable antenna is fed on the central conductor and through gaps in the shield, the current passes to the outside of the antenna to generate B1 field. This could achieve more favorable current distributions and better adaptation to the body curvature. Methods Finite difference time domain (FDTD) simulations are performed to optimize the positions of the gaps in the shield for a flat current profile. Lumped inductors are added to each end to reduce losses. The performance of a single antenna is compared to a fractionated dipole using B1 maps and MR thermometry. Finally, an array of eight coax dipoles is evaluated in simulations and used for in‐vivo scanning. Results An optimal configuration is found with gaps located at 10 cm from the center and inductor values of 28 nH. In comparison to the fractionated dipole antenna, in single antenna phantom measurements the coax dipole achieves similar B1 amplitude with 18% lower peak temperature. In simulations, the eight‐channel array of coax dipoles improved B1 homogeneity by 18%, along with small improvements in transmit efficiency and specific absorption rate (SAR). MRI measurements on three volunteers show more consistent performance for the coax dipoles. Conclusion The coax dipole is a novel antenna design with a flattened current distribution resulting in beneficial properties. Also, the flexible design of the coax dipoles allows better adaptation to the body curvature and can potentially be used for a wide range of imaging targets.
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Affiliation(s)
- Carel C van Leeuwen
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Bart R Steensma
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Dennis W J Klomp
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - Alexander J E Raaijmakers
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands.,Biomedical Engineering Department, Eindhoven University of Technology, Eindhoven, The Netherlands
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42
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Motovilova E, Tan ET, Taracila V, Vincent JM, Grafendorfer T, Shin J, Potter HG, Robb FJL, Sneag DB, Winkler SA. Stretchable self-tuning MRI receive coils based on liquid metal technology (LiquiTune). Sci Rep 2021; 11:16228. [PMID: 34376703 PMCID: PMC8355233 DOI: 10.1038/s41598-021-95335-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 07/23/2021] [Indexed: 01/14/2023] Open
Abstract
Magnetic resonance imaging systems rely on signal detection via radiofrequency coil arrays which, ideally, need to provide both bendability and form-fitting stretchability to conform to the imaging volume. However, most commercial coils are rigid and of fixed size with a substantial mean offset distance of the coil from the anatomy, which compromises the spatial resolution and diagnostic image quality as well as patient comfort. Here, we propose a soft and stretchable receive coil concept based on liquid metal and ultra-stretchable polymer that conforms closely to a desired anatomy. Moreover, its smart geometry provides a self-tuning mechanism to maintain a stable resonance frequency over a wide range of elongation levels. Theoretical analysis and numerical simulations were experimentally confirmed and demonstrated that the proposed coil withstood the unwanted frequency detuning typically observed with other stretchable coils (0.4% for the proposed coil as compared to 4% for a comparable control coil). Moreover, the signal-to-noise ratio of the proposed coil increased by more than 60% as compared to a typical, rigid, commercial coil.
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Affiliation(s)
- Elizaveta Motovilova
- grid.5386.8000000041936877XDepartment of Radiology, Weill Cornell Medicine, New York, NY 10065 USA ,grid.239915.50000 0001 2285 8823Department of Radiology, Hospital for Special Surgery, New York, NY 10021 USA
| | - Ek Tsoon Tan
- grid.239915.50000 0001 2285 8823Department of Radiology, Hospital for Special Surgery, New York, NY 10021 USA
| | - Victor Taracila
- grid.418143.b0000 0001 0943 0267GE Healthcare, Aurora, OH USA
| | - Jana M. Vincent
- grid.418143.b0000 0001 0943 0267GE Healthcare, Aurora, OH USA
| | | | - James Shin
- grid.5386.8000000041936877XDepartment of Radiology, Weill Cornell Medicine, New York, NY 10065 USA
| | - Hollis G. Potter
- grid.239915.50000 0001 2285 8823Department of Radiology, Hospital for Special Surgery, New York, NY 10021 USA
| | | | - Darryl B. Sneag
- grid.239915.50000 0001 2285 8823Department of Radiology, Hospital for Special Surgery, New York, NY 10021 USA
| | - Simone A. Winkler
- grid.5386.8000000041936877XDepartment of Radiology, Weill Cornell Medicine, New York, NY 10065 USA
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Nohava L, Czerny R, Roat S, Obermann M, Kuehne A, Frass-Kriegl R, Felblinger J, Ginefri JC, Laistler E. Flexible Multi-Turn Multi-Gap Coaxial RF Coils: Design Concept and Implementation for Magnetic Resonance Imaging at 3 and 7 Tesla. IEEE TRANSACTIONS ON MEDICAL IMAGING 2021; 40:1267-1278. [PMID: 33439836 DOI: 10.1109/tmi.2021.3051390] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Magnetic resonance has become a backbone of medical imaging but suffers from inherently low sensitivity. This can be alleviated by improved radio frequency (RF) coils. Multi-turn multi-gap coaxial coils (MTMG-CCs) introduced in this work are flexible, form-fitting RF coils extending the concept of the single-turn single-gap CC by introducing multiple cable turns and/or gaps. It is demonstrated that this enables free choice of the coil diameter, and thus, optimizing it for the application to a certain anatomical site, while operating at the self-resonance frequency. An equivalent circuit for MTMG-CCs is modeled to predict their resonance frequency. Possible configurations regarding size, number of turns and gaps, and cable types for different B 0 field strengths are calculated. Standard copper wire loop coils (SCs) and flexible CCs made from commercial coaxial cable were fabricated as receive-only coils for 3 T and transmit/receive coils at 7 T with diameters between 4 and 15 cm. Electromagnetic simulations are used to investigate the currents on MTMG-CCs, and demonstrate comparable specific absorption rate of 7 T CCs and SCs. Signal-to-noise ratio (SNR), transmit efficiency, and active detuning performance of CCs were compared in bench tests and MR experiments. For the form-fitted receive-only CCs at 3 T no significant SNR degradation was found as compared to flat SCs on a balloon phantom. Form-fitted transmit/receive CCs at 7 T showed higher transmit efficiency and SNR. MTMG-CCs can be sized to optimize sensitivity, are flexible and lightweight, and could therefore enable the fabrication of wearable coils with improved patient comfort.
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Port A, Luechinger R, Brunner DO, Pruessmann KP. Elastomer coils for wearable MR detection. Magn Reson Med 2021; 85:2882-2891. [PMID: 33433044 DOI: 10.1002/mrm.28662] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 11/20/2020] [Accepted: 12/07/2020] [Indexed: 01/06/2023]
Abstract
PURPOSE To explore the use of conductive elastomer for MR signal detection and the utility of this approach for wearable detector arrays. METHODS An elastomer filled with silver microparticles was used to form stretchable radiofrequency coils for MR detection. Their electrical performance in terms of the Qunloaded and Q ratio was assessed in the relaxed state and under repeated strain up to 40%. In a phantom imaging study, the signal-to-noise ratio yield of conductive elastomer coils was compared with that of a reference copper coil. Four elastomer coils were integrated with a stretchable textile substrate to form a wearable array for knee imaging. The array was employed for multiple-angle and kinematic knee imaging in vivo. RESULTS The elastomer coils proved highly stretchable and mechanically robust. Upon repeated stretching by 20%, a medium-sized coil element settled at Qunloaded of 42 in the relaxed state and 32 at full strain, reflecting sample-noise dominance. The signal-to-noise ratio of elastomer coils was found to be 8% to 16% lower than that achieved with a conventional copper coil. Multiple-angle and kinematic knee imaging with the wearable array yielded high-quality results indicating robustness of detection performance against stretching and warping of the array. CONCLUSION Conductive elastomer is a viable material for MR detection. Coils made from this material reconcile high stretchability and adequate electrical performance with ease of manufacturing. Conductive elastomer also offers inherent restoring forces and is readily washable and sanitizable, making it an excellent basis of wearable detector front ends.
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Affiliation(s)
- Andreas Port
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Roger Luechinger
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - David O Brunner
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Klaas P Pruessmann
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
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Zijlema SE, Tijssen RHN, van Dijk L, Hackett SL, Wolthaus JWH, Breimer W, Lagendijk JJW, van den Berg CAT. Improving the imaging performance of the 1.5 T MR-linac using a flexible, 32-channel, on-body receive array. Phys Med Biol 2020; 65:215008. [PMID: 32698168 DOI: 10.1088/1361-6560/aba87a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
High impedance coils (HICs) are suitable as a building block of receive arrays for MRI-guided radiotherapy (MRIgRT) as HICs do not require radiation-attenuating capacitors and dense support materials. Recently, we proved the feasibility of using HICs to create a radiation transparent (i.e. radiolucent) window. In this work, we constructed a fully functional 32-channel array based on this design. The anterior element is flexible and follows the shape of the subject, while the posterior element is rigid to support the subject. Both elements feature a 2 × 8 channel layout. Here, we discuss the construction process and characterize the array's radiolucency and imaging performance. The dosimetric impact of the array was quantified by assessing the surface dose increase and attenuation of a single beam. The imaging performance of the prototype was compared to the clinical array in terms of visual appearance, signal-to-noise ratio (SNR), and acceleration performance, both in phantom and in-vivo measurements. Dosimetry measurements showed that on-body placement changed the anterior and posterior surface dose by +3% and -16% of the dose maximum. Attenuation under the anterior support materials and conductors was 0.3% and ≤1.5%, respectively. Phantom and in-vivo imaging with this array demonstrated an improvement of the SNR at the surface and the image quality in general. Simultaneous irradiation did not affect the SNR. G-factors were reduced considerably and clinically used sequences could be accelerated by up to 45%, which would greatly reduce pre-beam imaging times. Finally, the maximally achievable temporal resolution of abdominal 3D cine imaging was improved to 1.1 s, which was > 5 × faster than could be achieved with the clinical array. This constitutes a big step towards the ability to resolve respiratory motion in 3D. In conclusion, the proposed 32-channel array is compatible with MRIgRT and can significantly reduce scan times and/or improve the image quality of all on-line scans.
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Affiliation(s)
- Stefan E Zijlema
- Department of Radiotherapy, University Medical Center Utrecht, Utrecht, the Netherlands. Computational Imaging Group for MR Diagnostics & Therapy, Center for Image Sciences, University Medical Center Utrecht, Utrecht, the Netherlands
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Deller TW, Mathew NK, Hurley SA, Bobb CM, McMillan AB. PET Image Quality Improvement for Simultaneous PET/MRI with a Lightweight MRI Surface Coil. Radiology 2020; 298:166-172. [PMID: 33141004 DOI: 10.1148/radiol.2020200967] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Background During simultaneous PET/MRI, flexible MRI surface coils that lay on the patient are often omitted from PET attenuation correction processing, leading to quantification bias in PET images. Purpose To identify potential PET image quality improvement by using a recently developed lightweight MRI coil technology for the anterior array (AA) surface coil in both a phantom and in vivo study. Materials and Methods A phantom study and a prospective in vivo study were performed with a PET/CT scanner under three conditions: (a) no MRI surface coil (standard of reference), (b) traditional AA coil, and (c) lightweight AA coil. AA coils were not used in attenuation correction processing to emulate clinical PET/MRI. For the phantom study, PET images were reconstructed with and without time of flight (TOF) to assess quantification accuracy and uniformity. The in vivo study consisted of 10 participants (mean age, 66 years ± 10 [standard deviation]; six men) referred for a PET/CT oncologic examination who had undergone imaging between October 2019 and February 2020. Assessment of image quantification bias (defined as the standard error of the mean values) was conducted by comparing mean liver region of interest standardized uptake values with the no-coil standard of reference. A Wilcoxon signed-rank test was used to establish significance. Results For TOF and non-TOF, respectively, the phantom study revealed a mean PET quantification bias of -9.0% and -8.6% with the traditional AA coil and a mean PET quantification bias of -4.3% and -4.0% with the lightweight AA coil. The coefficients of variation reduced from 4.3% and 6.2% with the traditional AA coil to 2.1% and 2.7% with the lightweight AA coil, which demonstrated a homogeneity benefit from the lightweight coil that was greater with, versus without, TOF reconstruction. For the in vivo study, the mean liver standardized uptake value error was -5.9% with the traditional AA coil (P = .002 vs no coil) and -2.4% with the lightweight AA coil (P = .004 vs no coil). Conclusion The lightweight anterior array coil reduced PET image quantification bias by more than 50% compared with the traditional coil. Using the lightweight coil and performing time of flight-based reconstruction each reduced the variation of error. © RSNA, 2020 Online supplemental material is available for this article.
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Affiliation(s)
- Timothy W Deller
- From the Departments of PET/MR Engineering (T.W.D.) and Clinical Development (C.M.B.), GE Healthcare, 3200 N Grandview Blvd, Waukesha, WI 53188; and Department of Radiology, University of Wisconsin-Madison, Wisconsin Institutes for Medical Research, Madison, Wis (N.K.M., S.A.H., A.B.M.)
| | - Nicholas K Mathew
- From the Departments of PET/MR Engineering (T.W.D.) and Clinical Development (C.M.B.), GE Healthcare, 3200 N Grandview Blvd, Waukesha, WI 53188; and Department of Radiology, University of Wisconsin-Madison, Wisconsin Institutes for Medical Research, Madison, Wis (N.K.M., S.A.H., A.B.M.)
| | - Samuel A Hurley
- From the Departments of PET/MR Engineering (T.W.D.) and Clinical Development (C.M.B.), GE Healthcare, 3200 N Grandview Blvd, Waukesha, WI 53188; and Department of Radiology, University of Wisconsin-Madison, Wisconsin Institutes for Medical Research, Madison, Wis (N.K.M., S.A.H., A.B.M.)
| | - Chad M Bobb
- From the Departments of PET/MR Engineering (T.W.D.) and Clinical Development (C.M.B.), GE Healthcare, 3200 N Grandview Blvd, Waukesha, WI 53188; and Department of Radiology, University of Wisconsin-Madison, Wisconsin Institutes for Medical Research, Madison, Wis (N.K.M., S.A.H., A.B.M.)
| | - Alan B McMillan
- From the Departments of PET/MR Engineering (T.W.D.) and Clinical Development (C.M.B.), GE Healthcare, 3200 N Grandview Blvd, Waukesha, WI 53188; and Department of Radiology, University of Wisconsin-Madison, Wisconsin Institutes for Medical Research, Madison, Wis (N.K.M., S.A.H., A.B.M.)
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Chaudhari AS, Kogan F, Pedoia V, Majumdar S, Gold GE, Hargreaves BA. Rapid Knee MRI Acquisition and Analysis Techniques for Imaging Osteoarthritis. J Magn Reson Imaging 2020; 52:1321-1339. [PMID: 31755191 PMCID: PMC7925938 DOI: 10.1002/jmri.26991] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 10/22/2019] [Accepted: 10/22/2019] [Indexed: 12/16/2022] Open
Abstract
Osteoarthritis (OA) of the knee is a major source of disability that has no known treatment or cure. Morphological and compositional MRI is commonly used for assessing the bone and soft tissues in the knee to enhance the understanding of OA pathophysiology. However, it is challenging to extend these imaging methods and their subsequent analysis techniques to study large population cohorts due to slow and inefficient imaging acquisition and postprocessing tools. This can create a bottleneck in assessing early OA changes and evaluating the responses of novel therapeutics. The purpose of this review article is to highlight recent developments in tools for enhancing the efficiency of knee MRI methods useful to study OA. Advances in efficient MRI data acquisition and reconstruction tools for morphological and compositional imaging, efficient automated image analysis tools, and hardware improvements to further drive efficient imaging are discussed in this review. For each topic, we discuss the current challenges as well as potential future opportunities to alleviate these challenges. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY STAGE: 3.
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Affiliation(s)
| | - Feliks Kogan
- Department of Radiology, Stanford University, Stanford, California, USA
| | - Valentina Pedoia
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
- Center of Digital Health Innovation (CDHI), University of California San Francisco, San Francisco, California, USA
| | - Sharmila Majumdar
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
- Center of Digital Health Innovation (CDHI), University of California San Francisco, San Francisco, California, USA
| | - Garry E. Gold
- Department of Radiology, Stanford University, Stanford, California, USA
- Department of Orthopaedic Surgery, Stanford University, Stanford, California, USA
- Department of Bioengineering, Stanford University, Stanford, California, USA
| | - Brian A. Hargreaves
- Department of Radiology, Stanford University, Stanford, California, USA
- Department of Bioengineering, Stanford University, Stanford, California, USA
- Department of Electrical Engineering, Stanford University, Stanford, California, USA
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Choi CH, Hong SM, Felder J, Shah NJ. The state-of-the-art and emerging design approaches of double-tuned RF coils for X-nuclei, brain MR imaging and spectroscopy: A review. Magn Reson Imaging 2020; 72:103-116. [DOI: 10.1016/j.mri.2020.07.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 06/16/2020] [Accepted: 07/01/2020] [Indexed: 12/18/2022]
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Zhang X, Zhang J, Gao Y, Qian M, Qu S, Quan Z, Yu M, Chen X, Wang Y, Pan G, Adriany G, Roe AW. A 16-Channel Dense Array for In Vivo Animal Cortical MRI/fMRI on 7T Human Scanners. IEEE Trans Biomed Eng 2020; 68:1611-1618. [PMID: 32991277 DOI: 10.1109/tbme.2020.3027296] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVE The purpose of the present study was to fabricate a novel RF coil exclusively for visualizing submillimeter tissue structure and probing neuronal activity in cerebral cortex over anesthetized and awake animals on 7T human scanners. METHODS A novel RF coil design has been proposed for visualizing submillimeter tissue structure and probing neuronal activity in cerebral cortex over anesthetized and awake animals on 7T human scanners: a local transmit coil was utilized to save space for auxiliary device installation; 16 receive-only loops were densely arranged over a 5 cm-diameter circular area, with a diameter of 1.3 cm for each loop. RESULTS In anesthetized macaque experiments, 60 μm T2*-weighted images were successfully obtained with cortical gyri and sulci exquisitely visualized; over awake macaques, bilateral activations of visual areas including V1, V2, V4, and MST were distinctly detected at 1 mm; over the cat, robust activations were recorded in areas 17 and 18 (V1 and V2) as well as in their connected area of lateral geniculate nucleus (LGN) at 0.3 mm resolution. CONCLUSION The promising brain imaging results along with flexibility in various size use of the presented design can be an effective and maneuverable solution to take one step close towards mesoscale cortical-related imaging. SIGNIFICANCE High-spatial-resolution brain imaging over large animals by using ultra-high-field (UHF) MRI will be helpful to understand and reveal functional brain organizations and the underlying mechanism in diseases.
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Collick BD, Behzadnezhad B, Hurley SA, Mathew NK, Behdad N, Lindsay SA, Robb F, Stormont RS, McMillan AB. Rapid development of application-specific flexible MRI receive coils. Phys Med Biol 2020; 65:19NT01. [PMID: 32975219 PMCID: PMC8064628 DOI: 10.1088/1361-6560/abaffb] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Over the last 30 years, there have been dramatic changes in phased array coil technology leading to increasing channel density and parallel imaging functionality. Current receiver array coils are rigid and often mismatched to patient's size. Recently there has been a move towards flexible coil technology, which is more conformal to the human anatomy. Despite the advances of so-called flexible surface coil arrays, these coils are still relatively rigid and limited in terms of design conformability, compromising signal-to-noise ratio (SNR) for flexibility, and are not designed for optimum parallel imaging performance. The purpose of this study is to report on the development and characterization of a 15-channel flexible foot and ankle coil, rapidly designed and constructed using highly decoupled radio-frequency (RF) coil elements. Coil performance was evaluated by performing SNR and g-factor measurements. In vivo testing was performed in a healthy volunteer using both the 15-channel coil and a commercially available 8-channel foot coil. The highly decoupled elements used in this design allow for extremely rapid development and prototyping of application-specific coils for different patient sizes (adult vs child) with minimal additional design consideration in terms of coil overlap and geometry. Image quality was comparable to a commercially available RF coil.
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Affiliation(s)
- B D Collick
- Department of Radiology, University of Wisconsin, Madison, WI 53705, United States of America. Author B D Collick and author B Behzadnezhad contributed equally to this work
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