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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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Cristant C, Kolasangiani K, Sadanand S, Bougherara H, Sussman D. Effect of Injection Parameters on the MRI and Dielectric Properties of Condensation-Cured Silicone. Polymers (Basel) 2023; 15:4670. [PMID: 38139922 PMCID: PMC10747146 DOI: 10.3390/polym15244670] [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: 10/27/2023] [Revised: 12/04/2023] [Accepted: 12/05/2023] [Indexed: 12/24/2023] Open
Abstract
Phantoms with tissue-mimicking properties play a crucial role in the calibration of medical imaging modalities, including Magnetic Resonance Imaging (MRI). Among these phantoms, silicone-based ones are widely used due to their long-term stability in MR imaging. Most of these phantoms are manufactured using traditional pour-mold techniques which often result in the production of air bubbles that can damage the phantom. This research investigates the feasibility of utilizing extrusion techniques to fabricate silicone phantoms and explores the effects of extrusion parameters including plunger speed and nozzle diameter on void content, T1 and T2 relaxation times, and dielectric properties. A custom double-syringe silicone extrusion apparatus was developed to prepare the silicone samples. The void content, relaxometry, and dielectric properties of extruded samples were measured and compared with traditional poured samples. The results show that extrusion parameters can affect the void content of the silicone samples. The presence of voids in the samples resulted in lower T1 values, indicating an inverse relationship between void content and relaxometry. This study demonstrates the potential of extrusion techniques for manufacturing silicone phantoms with reduced air bubble formation and provides valuable insights into the relationship between extrusion parameters and phantom properties.
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Affiliation(s)
- Conor Cristant
- Department of Electrical, Computer and Biomedical Engineering, Toronto Metropolitan University, Toronto, ON M5B 2K3, Canada; (C.C.); (S.S.)
- Institute for Biomedical Engineering, Science and Technology (iBEST), St. Michael’s Hospital & Toronto Metropolitan University, Toronto, ON M5B 1T8, Canada; (K.K.); (H.B.)
| | - Kamal Kolasangiani
- Institute for Biomedical Engineering, Science and Technology (iBEST), St. Michael’s Hospital & Toronto Metropolitan University, Toronto, ON M5B 1T8, Canada; (K.K.); (H.B.)
- Department of Mechanical and Industrial Engineering, Toronto Metropolitan University, Toronto, ON M5B 2K3, Canada
| | - Siddharth Sadanand
- Department of Electrical, Computer and Biomedical Engineering, Toronto Metropolitan University, Toronto, ON M5B 2K3, Canada; (C.C.); (S.S.)
- Institute for Biomedical Engineering, Science and Technology (iBEST), St. Michael’s Hospital & Toronto Metropolitan University, Toronto, ON M5B 1T8, Canada; (K.K.); (H.B.)
| | - Habiba Bougherara
- Institute for Biomedical Engineering, Science and Technology (iBEST), St. Michael’s Hospital & Toronto Metropolitan University, Toronto, ON M5B 1T8, Canada; (K.K.); (H.B.)
- Department of Mechanical and Industrial Engineering, Toronto Metropolitan University, Toronto, ON M5B 2K3, Canada
| | - Dafna Sussman
- Department of Electrical, Computer and Biomedical Engineering, Toronto Metropolitan University, Toronto, ON M5B 2K3, Canada; (C.C.); (S.S.)
- Institute for Biomedical Engineering, Science and Technology (iBEST), St. Michael’s Hospital & Toronto Metropolitan University, Toronto, ON M5B 1T8, Canada; (K.K.); (H.B.)
- Department of Obstetrics and Gynaecology, University of Toronto, Toronto, ON M5G 1E2, Canada
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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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