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Zhao Y, Bhosale AA, Zhang X. Multimodal surface coils for low field MR imaging. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.04.14.24305802. [PMID: 38699318 PMCID: PMC11065021 DOI: 10.1101/2024.04.14.24305802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
Low field MRI is safer and more cost effective than the high field MRI. One of the inherent problems of low field MRI is its low signal-to-noise ratio or sensitivity. In this work, we introduce a multimodal surface coil technique for signal excitation and reception to improve the RF magnetic field (B 1 ) efficiency and potentially improve MR sensitivity. The proposed multimodal surface coil consists of multiple identical resonators that are electromagnetically coupled to form a multimodal resonator. The field distribution of its lowest frequency mode is suitable for MR imaging applications. The prototype multimodal surface coils are built, and the performance is investigated and validated through numerical simulation, standard RF measurements and tests, and comparison with the conventional surface coil at low fields. Our results show that the B 1 efficiency of the multimodal surface coil outperforms that of the conventional surface coil which is known to offer the highest B 1 efficiency among all coil categories, i.e., volume coil, half-volume coil and surface coil. In addition, in low-field MRI, the required low-frequency coils often use large value capacitance to achieve the low resonant frequency which makes frequency tuning difficult. The proposed multimodal surface coil can be conveniently tuned to the required low frequency for low-field MRI with significantly reduced capacitance value, demonstrating excellent low-frequency operation capability over the conventional surface coil.
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Kim B, Chang Y, Choi HJ, Park KS, Yang JU, Kim E, Park SH. Development of a Stereotactic Radiosurgery Frame Adapter for a Multichannel MRI Coil. Stereotact Funct Neurosurg 2020; 99:159-166. [PMID: 33242875 DOI: 10.1159/000510476] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 07/27/2020] [Indexed: 11/19/2022]
Abstract
BACKGROUND The usage of multichannel brain MRI coils, which have several advantages over single-channel brain coils used for stereotactic radiosurgery (SRS), requires a frame adapter device to fit the frames inside the multichannel brain coils. However, such a frame adapter has not been developed until now. OBJECTIVE to develop an SRS frame adapter for multichannel MRI coils and verify the geometrical accuracy and signal-to-noise ratio (SNR) of the MR images obtained using multichannel MRI coils. METHODS We fabricated an SRS frame adapter for a 48-channel MRI coil using a three-dimensional (3D) printer. Furthermore, we obtained phantom and human-brain MR images with a 3.0 Tesla MRI scanner using multi- and single-channel coils. Computed tomography (CT) phantom images were also obtained as reference. We compared the coordinate errors of the multi- and single-channel coils to evaluate the geometrical accuracy. Two neurosurgeons measured the coordinates. In addition, we compared the SNR differences between multi- and single-channel coils using the T1- and T2-weighted brain images. RESULTS For the CT coordinate measurements, the correlation coefficient r = 1 and p < 0.001 with respect to the 3 axes (Δx, Δy, and Δz) and 3D errors (Δr) showed no interpersonal differences between the 2 neurosurgeons. The results obtained using the T1-weighted images showed that a multichannel coil had smaller coordinate errors in Δx, Δy, Δz, and Δr than that observed in case of a single-channel coil (p < 0.001). In case of the SNR measurements, most of the brain areas showed higher SNRs when using a multichannel coil compared with that observed when using a single-channel coil in the T1- and T2-weighted images. CONCLUSION Compared with single-channel coils, the use of multichannel MRI coils with a newly developed frame adapter is expected to ensure successful SRS treatments with improved geometrical accuracy and SNR.
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Affiliation(s)
- Byungmok Kim
- Department of Medical & Biological Engineering, Kyungpook National University, Daegu, Republic of Korea.,Department of Neurosurgery, Kyungpook National University Hospital, Daegu, Republic of Korea
| | - Yongmin Chang
- Department of Molecular Medicine, Kyungpook National University School of Medicine, Daegu, Republic of Korea.,Department of Radiology, Kyungpook National University Hospital, Daegu, Republic of Korea
| | - Hea Jung Choi
- Department of Medical & Biological Engineering, Kyungpook National University, Daegu, Republic of Korea
| | - Ki-Su Park
- Department of Neurosurgery, Kyungpook National University Hospital, Daegu, Republic of Korea.,Department of Neurosurgery, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - Ji-Ung Yang
- Department of Medical & Biological Engineering, Kyungpook National University, Daegu, Republic of Korea
| | - Eunji Kim
- Department of Medical & Biological Engineering, Kyungpook National University, Daegu, Republic of Korea
| | - Seong-Hyun Park
- Department of Neurosurgery, Kyungpook National University Hospital, Daegu, Republic of Korea, .,Department of Neurosurgery, Kyungpook National University School of Medicine, Daegu, Republic of Korea,
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Li Y, Lee J, Zhang L, Chen Q, Tie C, Luo C, Zhang X, Liang D, Liu X, Zheng H. Design and testing of a 24-channel head coil for MR imaging at 3 T. Magn Reson Imaging 2019; 58:162-173. [DOI: 10.1016/j.mri.2019.01.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 12/07/2018] [Accepted: 01/22/2019] [Indexed: 11/29/2022]
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Lee J, Ramirez MS, Walker CM, Chen Y, Yi S, Sandulache VC, Lai SY, Bankson JA. High-throughput hyperpolarized (13)C metabolic investigations using a multi-channel acquisition system. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 260:20-27. [PMID: 26397217 PMCID: PMC4628838 DOI: 10.1016/j.jmr.2015.08.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 08/27/2015] [Accepted: 08/29/2015] [Indexed: 06/05/2023]
Abstract
Magnetic resonance imaging and spectroscopy of hyperpolarized (HP) compounds such as [1-(13)C]-pyruvate have shown tremendous potential for offering new insight into disease and response to therapy. New applications of this technology in clinical research and care will require extensive validation in cells and animal models, a process that may be limited by the high cost and modest throughput associated with dynamic nuclear polarization. Relatively wide spectral separation between [1-(13)C]-pyruvate and its chemical endpoints in vivo are conducive to simultaneous multi-sample measurements, even in the presence of a suboptimal global shim. Multi-channel acquisitions could conserve costs and accelerate experiments by allowing acquisition from multiple independent samples following a single dissolution. Unfortunately, many existing preclinical MRI systems are equipped with only a single channel for broadband acquisitions. In this work, we examine the feasibility of this concept using a broadband multi-channel digital receiver extension and detector arrays that allow concurrent measurement of dynamic spectroscopic data from ex vivo enzyme phantoms, in vitro anaplastic thyroid carcinoma cells, and in vivo in tumor-bearing mice. Throughput and the cost of consumables were improved by up to a factor of four. These preliminary results demonstrate the potential for efficient multi-sample studies employing hyperpolarized agents.
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Affiliation(s)
- Jaehyuk Lee
- Department of Imaging Physics, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA
| | - Marc S Ramirez
- Department of Imaging Physics, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA
| | - Christopher M Walker
- Department of Imaging Physics, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA
| | - Yunyun Chen
- Department of Head & Neck Surgery, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA
| | - Stacey Yi
- Department of Imaging Physics, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA
| | - Vlad C Sandulache
- Department of Otolaryngology, Baylor College of Medicine, Houston, TX, USA
| | - Stephen Y Lai
- Department of Head & Neck Surgery, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA
| | - James A Bankson
- Department of Imaging Physics, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA.
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Pang Y, Wong EWH, Yu B, Zhang X. Design and numerical evaluation of a volume coil array for parallel MR imaging at ultrahigh fields. Quant Imaging Med Surg 2014; 4:50-6. [PMID: 24649435 DOI: 10.3978/j.issn.2223-4292.2014.02.07] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 02/26/2014] [Indexed: 11/14/2022]
Abstract
In this work, we propose and investigate a volume coil array design method using different types of birdcage coils for MR imaging. Unlike the conventional radiofrequency (RF) coil arrays of which the array elements are surface coils, the proposed volume coil array consists of a set of independent volume coils including a conventional birdcage coil, a transverse birdcage coil, and a helix birdcage coil. The magnetic fluxes of these three birdcage coils are intrinsically cancelled, yielding a highly decoupled volume coil array. In contrast to conventional non-array type volume coils, the volume coil array would be beneficial in improving MR signal-to-noise ratio (SNR) and also gain the capability of implementing parallel imaging. The volume coil array is evaluated at the ultrahigh field of 7T using FDTD numerical simulations, and the g-factor map at different acceleration rates was also calculated to investigate its parallel imaging performance.
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Affiliation(s)
- Yong Pang
- 1 Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA ; 2 Agilent Technologies, Santa Clara, CA, USA ; 3 Magwale, Palo Alto, CA, USA ; 4 UC Berkeley/UCSF Joint Graduate Group in Bioengineering, San Francisco & Berkeley, CA, USA ; 5 California Institute for Quantitative Biosciences (QB3), San Francisco, CA, USA
| | - Ernest W H Wong
- 1 Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA ; 2 Agilent Technologies, Santa Clara, CA, USA ; 3 Magwale, Palo Alto, CA, USA ; 4 UC Berkeley/UCSF Joint Graduate Group in Bioengineering, San Francisco & Berkeley, CA, USA ; 5 California Institute for Quantitative Biosciences (QB3), San Francisco, CA, USA
| | - Baiying Yu
- 1 Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA ; 2 Agilent Technologies, Santa Clara, CA, USA ; 3 Magwale, Palo Alto, CA, USA ; 4 UC Berkeley/UCSF Joint Graduate Group in Bioengineering, San Francisco & Berkeley, CA, USA ; 5 California Institute for Quantitative Biosciences (QB3), San Francisco, CA, USA
| | - Xiaoliang Zhang
- 1 Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA ; 2 Agilent Technologies, Santa Clara, CA, USA ; 3 Magwale, Palo Alto, CA, USA ; 4 UC Berkeley/UCSF Joint Graduate Group in Bioengineering, San Francisco & Berkeley, CA, USA ; 5 California Institute for Quantitative Biosciences (QB3), San Francisco, CA, USA
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Abstract
Fetal Magnetic Resonance Imaging (MRI) on clinical scanners has increasingly been realized as a powerful imaging tool and applied for studying the brain abnormalities and the potential of neurodevelopmental disabilities in vivo. The primarily used multi-echo fast imaging sequences reduce the motion artifacts with a tradeoff of image Signal-to-Noise Ratio (SNR) and resolution. In Radio Frequency (RF) hardware for MR signal excitation and reception, there are lack of dedicated RF coils for fetal imaging providing optimized performance in acquisition and safety. There is an urgent demand for novel hardware and fast imaging technology developments to overcome motion artifacts and improve sensitivity and safety. Recent studies have demonstrated that dedicated fetal RF transceiver arrays can improve the SNR, image coverage, and safety. In addition, emerging fast imaging technologies such as parallel imaging and compressed sensing would be advantageous in improving imaging speed and thus reducing motion artifacts in fetal imaging.
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Affiliation(s)
- Ye Li
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA
| | - Xiaoliang Zhang
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA
- UC Berkeley/UCSF Joint Graduate Group in Bioengineering, Berkeley & San Francisco, CA, USA
- California Institute for Quantitative Biosciences (QB3), University of California, San Francisco, CA, USA
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