{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T01:32:41Z","timestamp":1760232761544,"version":"build-2065373602"},"reference-count":94,"publisher":"MDPI AG","issue":"22","license":[{"start":{"date-parts":[[2022,11,19]],"date-time":"2022-11-19T00:00:00Z","timestamp":1668816000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003725","name":"National Research Foundation of Korea (NRF)","doi-asserted-by":"publisher","award":["NRF-2022R1A2C2010363","HR14C0002"],"award-info":[{"award-number":["NRF-2022R1A2C2010363","HR14C0002"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100003710","name":"Korea Health Industry Development Institute (KHIDI)","doi-asserted-by":"publisher","award":["NRF-2022R1A2C2010363","HR14C0002"],"award-info":[{"award-number":["NRF-2022R1A2C2010363","HR14C0002"]}],"id":[{"id":"10.13039\/501100003710","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In ultrahigh-field (UHF) magnetic resonance imaging (MRI) system, the RF power required to excite the nuclei of the target object increases. As the strength of the main magnetic field (B0 field) increases, the improvement of the RF transmit field (B1+ field) efficiency and receive field (B1\u2212 field) sensitivity of radio-frequency (RF) coils is essential to reduce their specific absorption rate and power deposition in UHF MRI. To address these problems, we previously proposed a method to simultaneously improve the B1+ field efficiency and B1\u2212 field sensitivity of 16-leg bandpass birdcage RF coils (BP-BC RF coils) by combining a multichannel wireless RF element (MCWE) and segmented cylindrical high-permittivity material (scHPM) comprising 16 elements in 7.0 T MRI. In this work, we further improved the performance of transmit\/receive RF coils. A new combination of RF coil with wireless element and HPM was proposed by comparing the BP-BC RF coil with the MCWE and the scHPM proposed in the previous study and the multichannel RF coils with a birdcage RF coil-type wireless element (BCWE) and the scHPM proposed in this study. The proposed 16-ch RF coils with the BCWE and scHPM provided excellent B1+ field efficiency and B1\u2212 field sensitivity improvement.<\/jats:p>","DOI":"10.3390\/s22228968","type":"journal-article","created":{"date-parts":[[2022,11,21]],"date-time":"2022-11-21T04:39:59Z","timestamp":1669005599000},"page":"8968","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["A New Combination of Radio-Frequency Coil Configurations Using High-Permittivity Materials and Inductively Coupled Structures for Ultrahigh-Field Magnetic Resonance Imaging"],"prefix":"10.3390","volume":"22","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8454-5002","authenticated-orcid":false,"given":"Jeung-Hoon","family":"Seo","sequence":"first","affiliation":[{"name":"Neuroscience Research Institute, Gachon University, Incheon 21988, Republic of Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4806-8488","authenticated-orcid":false,"given":"Young-Seung","family":"Jo","sequence":"additional","affiliation":[{"name":"Neuroscience Research Institute, Gachon University, Incheon 21988, Republic of Korea"},{"name":"Department of Electronics and Information Engineering, Korea University, Sejong 30019, Republic of Korea"}]},{"given":"Chang-Hyun","family":"Oh","sequence":"additional","affiliation":[{"name":"Department of Electronics and Information Engineering, Korea University, Sejong 30019, Republic of Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7408-8215","authenticated-orcid":false,"given":"Jun-Young","family":"Chung","sequence":"additional","affiliation":[{"name":"Department of Neuroscience, College of Medicine, Gachon University, Incheon 21565, Republic of Korea"}]}],"member":"1968","published-online":{"date-parts":[[2022,11,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"37","DOI":"10.1097\/00002142-199902000-00004","article-title":"Clinical rationale for very-high field (3.0 Tesla) functional magnetic resonance imaging","volume":"10","author":"Thulborn","year":"1999","journal-title":"Top. Magn. Reson. Imaging"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"588","DOI":"10.1002\/mrm.1080","article-title":"Imaging brain function in humans at 7 tesla","volume":"45","author":"Yacoub","year":"2001","journal-title":"Magn. Reson. Med."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"385","DOI":"10.1097\/01.rli.0000073442.88269.c9","article-title":"Magnetic resonance imaging at 3.0 Tesla: Challenges and advantages in clinical neurological imaging","volume":"38","author":"Frayne","year":"2003","journal-title":"Investig. Radiol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"13","DOI":"10.1002\/jmri.20356","article-title":"Routine clinical brain MRI sequences for use at 3.0 Tesla","volume":"22","author":"Lu","year":"2005","journal-title":"J. Magn. Reson. Imaging"},{"key":"ref_5","unstructured":"FDA (2019, June 27). Clears First 7T Magnetic Resonance Imaging Device, Available online: https:\/\/www.fda.gov\/NewsEvents\/Newsroom\/PressAnnouncements\/ucm580154.htm."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"91","DOI":"10.3233\/JAD-2011-0023","article-title":"Ultra-high field 7T MRI: A new tool for studying Alzheimer\u2019s disease","volume":"26","author":"Kerchner","year":"2011","journal-title":"J. Alzheimer\u2019s Dis."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"564","DOI":"10.1136\/jnnp-2016-315022","article-title":"7T MRI for neurodegenerative dementias in vivo: A systematic review of the literature","volume":"88","author":"McKiernan","year":"2017","journal-title":"J. Neurol. Neurosurg. Psychiatry"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"36","DOI":"10.1186\/s41747-021-00221-5","article-title":"Studying Alzheimer disease, Parkinson disease, and amyotrophic lateral sclerosis with 7-T magnetic resonance","volume":"5","author":"Costagli","year":"2021","journal-title":"Eur. Radiol. Exp."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1843","DOI":"10.1002\/alz.12501","article-title":"What can 7T sodium MRI tell us about cellular energy depletion and neurotransmission in Alzheimer\u2019s disease?","volume":"17","author":"Haeger","year":"2021","journal-title":"Alzheimer\u2019s Dement."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"3406","DOI":"10.21037\/qims-21-969","article-title":"Neuroimaging at 7 Tesla: A pictorial narrative review","volume":"12","author":"Okada","year":"2022","journal-title":"Quant. Imaging Med. Surg."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"24","DOI":"10.1002\/mrm.1156","article-title":"7T vs. 4T: RF power, homogeneity, and signal-to-noise comparison in head images","volume":"46","author":"Vaughan","year":"2001","journal-title":"Magn. Reson. Med."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"519","DOI":"10.1002\/jmri.10390","article-title":"High field human imaging","volume":"18","author":"Norris","year":"2003","journal-title":"J. Magn. Reson. Imaging"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1425","DOI":"10.1016\/j.neuroimage.2009.05.015","article-title":"fMRI at 1.5, 3 and 7 T: Characterising BOLD signal changes","volume":"47","author":"Francis","year":"2009","journal-title":"NeuroImage"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1015","DOI":"10.1016\/j.neuroimage.2011.05.010","article-title":"Clinical fMRI: Evidence for a 7 T benefit over 3 T","volume":"57","author":"Beisteiner","year":"2011","journal-title":"NeuroImage"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"528","DOI":"10.1007\/s00330-012-2619-7","article-title":"Clinical application of multi-contrast 7-T MR imaging in multiple sclerosis: Increased lesion detection compared to 3 T confined to grey matter","volume":"23","author":"Kilsdonk","year":"2013","journal-title":"Eur. Radiol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1472","DOI":"10.1093\/brain\/aww037","article-title":"Increased cortical grey matter lesion detection in multiple sclerosis with 7 T MRI: A post-mortem verification study","volume":"139","author":"Kilsdonk","year":"2016","journal-title":"Brain"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"20180492","DOI":"10.1259\/bjr.20180492","article-title":"Clinical 7 T MRI: Are we there yet? A review about magnetic resonance imaging at ultra-high field","volume":"92","author":"Barisano","year":"2019","journal-title":"Br. J. Radiol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"218","DOI":"10.1002\/mrm.22174","article-title":"Experimental and numerical assessment of MRI-induced temperature change and SAR distributions in phantoms and in vivo","volume":"63","author":"Oh","year":"2010","journal-title":"Magn. Reson. Med."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"509","DOI":"10.1148\/radiol.2019182742","article-title":"Safety considerations of 7-T MRI in clinical practice","volume":"292","author":"Hoff","year":"2019","journal-title":"Radiology"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"653","DOI":"10.1002\/mrm.27350","article-title":"Changes in the specific absorption rate (SAR) of radiofrequency energy in patients with retained cardiac leads during MRI at 1.5 T and 3 T","volume":"81","author":"Golestanirad","year":"2019","journal-title":"Magn. Reson. Med."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1573","DOI":"10.1002\/jmri.25723","article-title":"7T: Physics, safety, and potential clinical applications","volume":"46","author":"Kraff","year":"2017","journal-title":"J. Magn. Reson. Imaging"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"35","DOI":"10.2463\/mrms.2014-0004","article-title":"Assessment of sensations experienced by subjects during MR imaging examination at 7T","volume":"14","author":"Uwano","year":"2015","journal-title":"Magn. Reson. Med. Sci."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1265","DOI":"10.1002\/jmri.27139","article-title":"Subjectively reported effects experienced in an actively shielded 7T MRI: A large-scale study","volume":"52","author":"Hansson","year":"2020","journal-title":"J. Magn. Reson. Imaging"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"333","DOI":"10.1002\/jmri.27319","article-title":"7T MR safety","volume":"53","author":"Fagan","year":"2021","journal-title":"J. Magn. Reson. Imaging"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"e4656","DOI":"10.1002\/nbm.4656","article-title":"Performance and safety assessment of an integrated transmit array for body imaging at 7 T under consideration of specific absorption rate, tissue temperature, and thermal dose","volume":"35","author":"Fiedler","year":"2022","journal-title":"NMR Biomed."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"922","DOI":"10.1118\/1.595995","article-title":"Radiofrequency penetration and absorption in the human body: Limitations to high field whole-body nuclear magnetic resonance imaging","volume":"14","year":"1987","journal-title":"Med. Phys."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"467","DOI":"10.1002\/mrm.1910220254","article-title":"Electromagnetic fields of surface coil in vivo NMR at high frequencies","volume":"22","author":"Keltner","year":"1991","journal-title":"Magn. Reson. Med."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"144","DOI":"10.1111\/j.1749-6632.1992.tb49604.x","article-title":"Homogeneous tissue model estimates of RF power deposition in human NMR studies. Local elevations predicted in surface coil decoupling","volume":"649","author":"Bottomley","year":"1992","journal-title":"Ann. N. Y. Acad. Sci."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"315","DOI":"10.1002\/mrm.21782","article-title":"Electrodynamic constraints on homogeneity and radiofrequency power deposition in multiple coil excitations","volume":"61","author":"Lattanzi","year":"2009","journal-title":"Magn. Reson. Med."},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Puddu, C., Fanti, A., Curreli, N., and Mazzarella, G. (2014, January 10\u201311). Challenging the lumped birdcage coil model for high field MRI. Proceedings of the IEEE 2014 Loughborough Antennas & Propagation Conference (LAPC), Loughborough, Leicestershire, UK.","DOI":"10.1109\/LAPC.2014.6996383"},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Woo, M.K., DelaBarre, L., Waks, M., Radder, J., Choi, U.-S., Lagore, R., Ugurbil, K., and Adriany, G. (2021). A 16-channel dipole antenna array for human head magnetic resonance imaging at 10.5 tesla. Sensors, 21.","DOI":"10.3390\/s21217250"},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Hong, S.-E., Oh, S., and Choi, H.-D. (2021). RF exposure assessment for various poses of patient assistant in open MRI environment. Appl. Sci., 11.","DOI":"10.3390\/app11114967"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"630","DOI":"10.1088\/0031-9155\/23\/4\/006","article-title":"RF magnetic field penetration, phase shift and power dissipation in biological tissue: Implications for NMR imaging","volume":"23","author":"Bottomley","year":"1978","journal-title":"Phys. Med. Biol."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"105","DOI":"10.1002\/mrm.1910090112","article-title":"Increased RF power absorption in MR imaging due to RF coupling between body coil and surface coil","volume":"9","author":"Buchli","year":"1989","journal-title":"Magn. Reson. Med."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"117","DOI":"10.1002\/bem.2250110203","article-title":"Magnetic resonance imaging: Calculation of rates of energy absorption by a human-torso model","volume":"11","author":"Grandolfo","year":"1990","journal-title":"Bioelectromagnetics"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"88","DOI":"10.1109\/10.477704","article-title":"Spatial distribution of high-frequency electromagnetic energy in human head during MRI: Numerical results and measurements","volume":"43","author":"Simunic","year":"1996","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"953","DOI":"10.1002\/mrm.1910380615","article-title":"On the SAR and field inhomogeneity of birdcage coils loaded with the human head","volume":"38","author":"Jin","year":"1997","journal-title":"Magn. Reson. Med."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"122303","DOI":"10.1118\/1.4829527","article-title":"An RF dosimeter for independent SAR measurement in MRI scanners","volume":"40","author":"Qian","year":"2013","journal-title":"Med. Phys."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"2810","DOI":"10.1002\/mrm.28895","article-title":"Safety and imaging performance of two-channel RF shimming for fetal MRI at 3T","volume":"86","author":"Yetisir","year":"2021","journal-title":"Magn. Reson. Med."},{"key":"ref_40","doi-asserted-by":"crossref","unstructured":"Noetscher, G.M., Serano, P., Wartman, W.A., Fujimoto, K., and Makarov, S.N. (2021). Visible Human Project\u00ae female surface based computational phantom (Nelly) for radio-frequency safety evaluation in MRI coils. PLoS ONE, 16.","DOI":"10.1371\/journal.pone.0260922"},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Seo, J.-H., Ryu, Y., and Chung, J.-Y. (2022). Simulation study of radio frequency safety and the optimal size of a single-channel surface radio frequency coil for mice at 9.4 T magnetic resonance imaging. Sensors, 22.","DOI":"10.3390\/s22114274"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"168","DOI":"10.1016\/j.mri.2021.10.011","article-title":"Average SAR prediction, validation, and evaluation for a compact MR scanner head-sized RF coil","volume":"85","author":"Tarasek","year":"2022","journal-title":"Magn. Reson. Imaging"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"1333","DOI":"10.3390\/ma4081333","article-title":"Resonant mode reduction in radiofrequency volume coils for ultrahigh field magnetic resonance imaging","volume":"4","author":"Pang","year":"2011","journal-title":"Materials"},{"key":"ref_44","doi-asserted-by":"crossref","unstructured":"Santarelli, M.F., Giovannetti, G., Hartwig, V., Celi, S., Positano, V., and Landini, L. (2021). The core of medical imaging: State of the art and perspectives on the detectors. Electronics, 10.","DOI":"10.3390\/electronics10141642"},{"key":"ref_45","doi-asserted-by":"crossref","unstructured":"Yoon, J.-S., Kim, J.-M., Chung, H.-J., Jeong, Y.-J., Jeong, G.-W., Park, I., Kim, G.-W., and Oh, C.-H. (2021). Development of a proton-frequency-transparent birdcage radiofrequency coil for in vivo 13C MRS\/MRSI study in a 3.0 T MRI system. Appl. Sci., 11.","DOI":"10.3390\/app112311445"},{"key":"ref_46","doi-asserted-by":"crossref","unstructured":"Seo, J.-H., and Chung, J.-Y. (2022). A preliminary study for reference RF coil at 11.7 T MRI: Based on electromagnetic field simulation of hybrid-BC RF coil according to diameter and length at 3.0, 7.0 and 11.7 T. Sensors, 22.","DOI":"10.3390\/s22041512"},{"key":"ref_47","doi-asserted-by":"crossref","unstructured":"Seo, J.-H., Han, Y., and Chung, J.-Y. (2022). A comparative study of birdcage RF coil configurations for ultra-high field magnetic resonance imaging. Sensors, 22.","DOI":"10.3390\/s22051741"},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"336","DOI":"10.1002\/mrm.1910020404","article-title":"Estimating radiofrequency power deposition in body NMR imaging","volume":"2","author":"Bottomley","year":"1985","journal-title":"Magn. Reson. Med."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"722","DOI":"10.1002\/mrm.1910030508","article-title":"The field dependence of NMR imaging. I. Laboratory assessment of signal-to-noise ratio and power deposition","volume":"3","author":"Chen","year":"1986","journal-title":"Magn. Reson. Med."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"318","DOI":"10.1002\/(SICI)1099-1492(199908)12:5<318::AID-NBM598>3.0.CO;2-G","article-title":"On RF power and dielectric resonances in UHF MRI","volume":"12","author":"Robitaille","year":"1999","journal-title":"NMR Biomed."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"46","DOI":"10.1002\/1522-2586(200007)12:1<46::AID-JMRI6>3.0.CO;2-D","article-title":"Sensitivity and power deposition in a high field imaging experiment","volume":"12","author":"Hoult","year":"2000","journal-title":"J. Magn. Reson. Imaging"},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"284","DOI":"10.1002\/(SICI)1522-2594(200002)43:2<284::AID-MRM16>3.0.CO;2-C","article-title":"A transmit-only\/receive-only (TORO) RF system for high field MRI\/MRS applications","volume":"43","author":"Barberi","year":"2000","journal-title":"Magn. Reson. Med."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"684","DOI":"10.1002\/mrm.1091","article-title":"Signal-to-noise ratio and absorbed power as functions of main magnetic field strength, and definition of \u201c90 degrees\u201d RF pulse for the head in the birdcage coil","volume":"45","author":"Collins","year":"2001","journal-title":"Magn. Reson. Med."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"982","DOI":"10.1002\/mrm.10137","article-title":"Analysis of wave behavior in lossy dielectric samples at high field","volume":"47","author":"Yang","year":"2002","journal-title":"Magn. Reson. Med."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"143","DOI":"10.2528\/PIERL20072706","article-title":"Development of compact and flexible quadrature hybrid coupler using coaxial cable with capacitive loading for 1.5T indigenous MRI system","volume":"93","author":"Apurva","year":"2020","journal-title":"Prog. Electromagn. Res. Lett."},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"1364","DOI":"10.1109\/TBME.2014.2313619","article-title":"Magnetic resonance imaging at ultrahigh fields","volume":"61","year":"2014","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"1299","DOI":"10.1002\/mrm.28784","article-title":"Specific absorption rate and temperature in neonate models resulting from exposure to a 7T head coil","volume":"86","author":"Malik","year":"2021","journal-title":"Magn. Reson. Med."},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"1434","DOI":"10.1002\/mrm.29283","article-title":"Evaluation of specific absorption rate and heating in children exposed to a 7T MRI head coil","volume":"88","author":"Malik","year":"2022","journal-title":"Magn. Reson. Med."},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"604","DOI":"10.1002\/mrm.1910030413","article-title":"The intrinsic signal-to-noise ratio in NMR imaging","volume":"3","author":"Edelstein","year":"1986","journal-title":"Magn. Reson. Med."},{"key":"ref_60","doi-asserted-by":"crossref","first-page":"22","DOI":"10.1002\/mrm.10678","article-title":"Signal-to-noise ratio and parallel imaging performance of a 16-channel receive-only brain coil array at 3.0 Tesla","volume":"51","author":"Ledden","year":"2004","journal-title":"Magn. Reson. Med."},{"key":"ref_61","doi-asserted-by":"crossref","first-page":"361","DOI":"10.1002\/sca.21217","article-title":"Development of double-layer coupled coil for improving S\/N in 7 T small-animal MRI","volume":"37","author":"Kim","year":"2015","journal-title":"Scanning"},{"key":"ref_62","doi-asserted-by":"crossref","first-page":"515","DOI":"10.1002\/sca.21290","article-title":"Magnetic field sensitivity at 7-T using dual-helmholtz transmit-only coil and 12-channel receive-only bended coil","volume":"38","author":"Kim","year":"2016","journal-title":"Scanning"},{"key":"ref_63","doi-asserted-by":"crossref","unstructured":"Kim, K.-N., Hernandez, D., Seo, J.-H., Noh, Y., Han, Y., Ryu, Y.C., and Chung, J.-Y. (2019). Quantitative assessment of phased array coils with different numbers of receiving channels in terms of signal-to-noise ratio and spatial noise variation in magnetic resonance imaging. PLoS ONE, 14.","DOI":"10.1371\/journal.pone.0219407"},{"key":"ref_64","doi-asserted-by":"crossref","unstructured":"Giovannetti, G., Flori, A., Martini, N., Francischello, R., Aquaro, G.D., Pingitore, A., and Frijia, F. (2021). Sodium radiofrequency coils for magnetic resonance: From design to applications. Electronics, 10.","DOI":"10.3390\/electronics10151788"},{"key":"ref_65","doi-asserted-by":"crossref","first-page":"352","DOI":"10.1111\/j.1151-2916.1973.tb12684.x","article-title":"High-permittivity temperature-stable ceramic dielectrics with low microwave loss","volume":"56","author":"Kell","year":"1973","journal-title":"Am. Ceram. Soc."},{"key":"ref_66","doi-asserted-by":"crossref","first-page":"6334","DOI":"10.1002\/adma.201301752","article-title":"Flexible nanodielectric materials with high permittivity for power energy storage","volume":"25","author":"Dang","year":"2013","journal-title":"Adv. Mater."},{"key":"ref_67","doi-asserted-by":"crossref","first-page":"158","DOI":"10.1016\/j.mri.2017.07.019","article-title":"Large improvement of RF transmission efficiency and reception sensitivity for human in vivo 31P MRS imaging using ultrahigh dielectric constant materials at 7 T","volume":"42","author":"Lee","year":"2017","journal-title":"Magn. Reson. Imaging"},{"key":"ref_68","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1016\/j.jmr.2018.12.013","article-title":"High permittivity ceramics improve the transmit field and receive efficiency of a commercial extremity coil at 1.5 Tesla","volume":"299","author":"Zivkovic","year":"2019","journal-title":"J. Magn. Reson."},{"key":"ref_69","doi-asserted-by":"crossref","first-page":"106835","DOI":"10.1016\/j.jmr.2020.106835","article-title":"An artificial dielectric slab for ultrahigh field MRI: Proof of concept","volume":"320","author":"Vorobyev","year":"2020","journal-title":"J. Magn. Reson."},{"key":"ref_70","doi-asserted-by":"crossref","first-page":"262","DOI":"10.1002\/cmr.10047","article-title":"Use of mutually inductive coupling in probe design","volume":"15","author":"Hoult","year":"2002","journal-title":"Concepts Magn. Reson."},{"key":"ref_71","doi-asserted-by":"crossref","first-page":"236","DOI":"10.1002\/cmr.b.20122","article-title":"Inductively coupled RF coil design for simultaneous microimaging of multiple samples","volume":"33B","author":"Wang","year":"2008","journal-title":"Concepts Magn. Reson. B"},{"key":"ref_72","doi-asserted-by":"crossref","first-page":"351","DOI":"10.1016\/j.mri.2014.12.004","article-title":"Inductively coupled wireless RF coil arrays","volume":"33","author":"Bulumulla","year":"2015","journal-title":"Magn. Reson. Imaging"},{"key":"ref_73","doi-asserted-by":"crossref","first-page":"124704","DOI":"10.1063\/1.4972391","article-title":"MRI surface-coil pair with strong inductive coupling","volume":"87","author":"Mett","year":"2016","journal-title":"Rev. Sci. Instrum."},{"key":"ref_74","doi-asserted-by":"crossref","first-page":"378","DOI":"10.4283\/JMAG.2017.22.3.378","article-title":"Birdcage coil with inductively coupled RF coil array for improving |B1| field sensitivity in 7-T MRI","volume":"22","author":"Byun","year":"2017","journal-title":"J. Magn."},{"key":"ref_75","doi-asserted-by":"crossref","first-page":"192","DOI":"10.4283\/JMAG.2018.23.2.192","article-title":"Surface coil with an inductively coupled wireless surface and volume coil for improving the magnetic field sensitivity at 400-MHz MRI","volume":"23","author":"Seo","year":"2018","journal-title":"J. Magn."},{"key":"ref_76","doi-asserted-by":"crossref","unstructured":"Mahmood, M.F., Gharghan, S.K., Mohammed, S.L., Al-Naji, A., and Chahl, J. (2021). Design of powering wireless medical sensor based on spiral-spider coils. Designs, 5.","DOI":"10.3390\/designs5040059"},{"key":"ref_77","doi-asserted-by":"crossref","first-page":"912","DOI":"10.1002\/mrm.24176","article-title":"Simulations of high permittivity materials for 7 T neuroimaging and evaluation of a new barium titanate-based dielectric","volume":"67","author":"Teeuwisse","year":"2012","journal-title":"Magn. Reson. Med."},{"key":"ref_78","doi-asserted-by":"crossref","first-page":"801","DOI":"10.1049\/el.2016.0533","article-title":"Influence of biological subject, shielding cage, and resonance frequency on radio wave propagation in a birdcage coil","volume":"52","author":"Seo","year":"2016","journal-title":"Electron. Lett."},{"key":"ref_79","doi-asserted-by":"crossref","unstructured":"Ahmad, S.F., Kim, Y.C., Choi, I.C., and Kim, H.D. (2020). Recent progress in birdcage RF coil technology for MRI system. Diagnostics, 10.","DOI":"10.3390\/diagnostics10121017"},{"key":"ref_80","doi-asserted-by":"crossref","unstructured":"Kim, Y.C., Kim, H.D., Yun, B.-J., and Ahmad, S.F. (2020). A simple analytical solution for the designing of the birdcage RF coil used in NMR imaging applications. Appl. Sci., 10.","DOI":"10.3390\/app10072242"},{"key":"ref_81","first-page":"302","article-title":"Numerical solution of initial boundary value problems involving Maxwell\u2019s equations in isotropic media","volume":"14","author":"Yee","year":"1996","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_82","doi-asserted-by":"crossref","first-page":"391","DOI":"10.1002\/mrm.27022","article-title":"Approaching ultimate intrinsic specific absorption rate in radiofrequency shimming using high-permittivity materials at 7 Tesla","volume":"80","author":"Haemer","year":"2018","journal-title":"Magn. Reson. Med."},{"key":"ref_83","doi-asserted-by":"crossref","first-page":"290","DOI":"10.1002\/mrm.24244","article-title":"On consideration of radiated power in RF field simulations for MRI","volume":"69","author":"Liu","year":"2013","journal-title":"Magn. Reson. Med."},{"key":"ref_84","doi-asserted-by":"crossref","first-page":"435","DOI":"10.1002\/jmri.23988","article-title":"Radiofrequency field enhancement with high dielectric constant (HDC) pads in a receive array coil at 3.0 T","volume":"38","author":"Yang","year":"2013","journal-title":"J. Magn. Reson. Imaging"},{"key":"ref_85","doi-asserted-by":"crossref","first-page":"1432","DOI":"10.1002\/jmri.24689","article-title":"Numerical evaluation of image homogeneity, signal-to-noise ratio, and specific absorption rate for human brain imaging at 1.5, 3, 7, 10.5, and 14 T in an 8-channel transmit\/receive array","volume":"41","author":"Cao","year":"2015","journal-title":"J. Magn. Reson. Imaging"},{"key":"ref_86","doi-asserted-by":"crossref","first-page":"8","DOI":"10.1002\/cmr.b.21317","article-title":"Effects of anatomical differences on electromagnetic fields, SAR, and temperature change","volume":"46","author":"Alon","year":"2016","journal-title":"Concepts Magn. Reson. Part B Magn. Reson. Eng."},{"key":"ref_87","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1002\/cmr.b.21319","article-title":"Dependence of B1+ and B1\u2212 field patterns of surface coils on the electrical properties of the sample and the MR operating frequency","volume":"46","author":"Vaidya","year":"2016","journal-title":"Concepts Magn. Reson. Part B Magn. Reson. Eng."},{"key":"ref_88","doi-asserted-by":"crossref","first-page":"1233","DOI":"10.1002\/mrm.27095","article-title":"Transverse slot antennas for high field MRI","volume":"80","author":"Alon","year":"2018","journal-title":"Magn. Reson. Med."},{"key":"ref_89","doi-asserted-by":"crossref","first-page":"355","DOI":"10.1007\/s10334-017-0657-5","article-title":"Manipulating transmit and receive sensitivities of radiofrequency surface coils using shielded and unshielded high-permittivity materials","volume":"31","author":"Vaidya","year":"2018","journal-title":"Magn. Reson. Mater. Phys. Biol. Med."},{"key":"ref_90","doi-asserted-by":"crossref","first-page":"431","DOI":"10.1002\/jmri.25936","article-title":"Improved detection of fMRI activation in the cerebellum at 7 T with dielectric pads extending the imaging region of a commercial head coil","volume":"48","author":"Vaidya","year":"2018","journal-title":"J. Magn. Reson. Imaging"},{"key":"ref_91","doi-asserted-by":"crossref","first-page":"173","DOI":"10.1002\/1099-0534(2000)12:4<173::AID-CMR1>3.0.CO;2-Q","article-title":"The principle of reciprocity in signal strength calculations\u2014A mathematical guide","volume":"12","author":"Hoult","year":"2000","journal-title":"Concepts Magn. Reson."},{"key":"ref_92","doi-asserted-by":"crossref","first-page":"616","DOI":"10.3938\/jkps.65.616","article-title":"Effective arrangement of separated transmit-only\/receive-only RF coil for improvement of B1 homogeneity at 7 Tesla","volume":"65","author":"Im","year":"2014","journal-title":"J. Korean Phys. Soc."},{"key":"ref_93","doi-asserted-by":"crossref","first-page":"11","DOI":"10.1002\/cmr.b.20185","article-title":"Studies of RF shimming techniques with minimization of RF power deposition and their associated temperature changes","volume":"39B","author":"Tang","year":"2011","journal-title":"Concepts Magn. Reson. Part B Magn. Reson. Eng."},{"key":"ref_94","doi-asserted-by":"crossref","unstructured":"Herrmann, T., Liebig, T., Mallow, J., Bruns, C., Stadler, J., Mylius, J., Brosch, M., Svedja, J.T., Chen, Z., and Rennings, A. (2018). Metamaterial-based transmit and receive system for whole-body magnetic resonance imaging at ultra-high magnetic fields. PLoS ONE, 13.","DOI":"10.1371\/journal.pone.0191719"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/22\/8968\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T01:21:59Z","timestamp":1760145719000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/22\/8968"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,11,19]]},"references-count":94,"journal-issue":{"issue":"22","published-online":{"date-parts":[[2022,11]]}},"alternative-id":["s22228968"],"URL":"https:\/\/doi.org\/10.3390\/s22228968","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2022,11,19]]}}}