Wireless, Battery-Free, and Fully Implantable Micro-Coil System for 7 T Brain MRI

Ullah, Sana; Zada, Muhammad; Basir, Abdul; Yoo, Hyoungsuk

doi:10.1109/tbcas.2022.3179839

Cited by 13 publications

(11 citation statements)

References 47 publications

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“…Having the electronics close to the patient helps to provide better SNRs (reduces the need for lengths of lossy cables to the pre-amplifiers, for example) but at the expense of equipment and cabling being required inside an already crowded magnet bore. To help mitigate some of this bore overcrowding, work has been done on wireless power transfer to power in-bore electronics [329], [330], [331], which also requires low-power in-bore electronics. With low-power in-bore electronics, dynamic ranges can be limited and so methods for resolving this low dynamic range are being studied [332].…”

Section: Microwave Enhanced Magnetic Resonance Imagingmentioning

confidence: 99%

“…For the SNR reasons, it is desirable to have the antennas placed as close as possible to the field of view of interest. Besides traditional external coils and antennas, implantable antennas and associated low-power electronics for imaging are being studied for use at 7 T [329]. Since these implantable electronics are metallic in nature, unwanted heating and hot spots must be studied to prevent injury to the patient.…”

Section: Microwave Enhanced Magnetic Resonance Imagingmentioning

confidence: 99%

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Applications of Microwaves in Medicine

Chiao

Lin

et al. 2023

IEEE J. Microw.

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Advances and updates in medical applications utilizing microwave techniques and technologies are reviewed in this paper. The article aims to provide an overview of enablers for microwave medical applications and their recent progress. The emphasis focuses on the applications of microwaves, in the following order, for 1) signal and data communication for implants and wearables through the human body, 2) electromagnetic energy transfer through tissues, 3) noninvasive, remote or in situ physical and biochemical sensing, and 4) therapeutic purposes by changing tissue properties with controlled thermal effects. For signal and data communication and wireless power transfer, implant and wearable applications are discussed in the categories of pacemakers, endoscopic capsules, brain interfaces, intraocular, cardiac and intracranial pressure sensors, neurostimulators, endoluminal implants, artificial retina, smart lenses, and cochlear implants. For noninvasive sensing, remote vital sign radar, biological cell probing, magnetic resonance and microwave imaging, biochemical, blood glucose, hydration and biomarker sensing applications are introduced. For therapeutic uses, the developments of microwave ablation, balloon angioplasty, and hyperthermia applications are reviewed. The scopes of this article mainly concentrate on the research and development efforts in the past 20 years. Recent review articles on specific topics are cited with accomplishment highlights and trends deliberated. At the end of this article, a brief history of the IEEE Microwave Theory and Techniques Society (MTT-S) Biological Effects and Medical Applications committee and the contributions by its members to the promotion and advancement of microwave technologies in medical fields are chronicled.

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Section: Microwave Enhanced Magnetic Resonance Imagingmentioning

confidence: 99%

Section: Microwave Enhanced Magnetic Resonance Imagingmentioning

confidence: 99%

Applications of Microwaves in Medicine

Chiao

Lin

et al. 2023

IEEE J. Microw.

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“…Imaging centers typically need five to seven separate coils on hand, targeting various anatomies, such as brain, spine, torso, shoulder, knee, foot/ankle, hand/ wrist, cardiac, and pelvis, which greatly adds to the overall hardware cost. The advancement in wearable technology has spurred the development of flexible and conformal devices or systems, aiming to address challenges in health care and personal monitoring (20)(21)(22)(23)(24)(25). Specifically, recent developments in MRI receive coils have gravitated toward more form-fitting, flexible designs.…”

Section: Introductionmentioning

confidence: 99%

Wireless, customizable coaxially shielded coils for magnetic resonance imaging

Wu,

Zhu,

Anderson

et al. 2024

Sci. Adv.

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Anatomy-specific radio frequency receive coil arrays routinely adopted in magnetic resonance imaging (MRI) for signal acquisition are commonly burdened by their bulky, fixed, and rigid configurations, which may impose patient discomfort, bothersome positioning, and suboptimal sensitivity in certain situations. Herein, leveraging coaxial cables’ inherent flexibility and electric field confining property, we present wireless, ultralightweight, coaxially shielded, passive detuning MRI coils achieving a signal-to-noise ratio comparable to or surpassing that of commercially available cutting-edge receive coil arrays with the potential for improved patient comfort, ease of implementation, and substantially reduced costs. The proposed coils demonstrate versatility by functioning both independently in form-fitting configurations, closely adapting to relatively small anatomical sites, and collectively by inductively coupling together as metamaterials, allowing for extension of the field of view of their coverage to encompass larger anatomical regions without compromising coil sensitivity. The wireless, coaxially shielded MRI coils reported herein pave the way toward next-generation MRI coils.

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“…To evaluate losses over the shortest wireless link, the in-body path loss (see Fig. 1) quantifies the attenuation in power density of EM waves propagating in the body, from the implanted antenna to the body-air interface [21], [38], [39], [40], [41]. In [32], approximate expressions of the in-body path loss are derived in order to determine the maximum power density reaching free space, including analytic approximations of the near-field losses of implanted antennas.…”

Section: Introductionmentioning

confidence: 99%

Analytic Approximation of In-Body Path Loss for Implanted Antennas

Gao

Šipuš

Skrivervik

2023

IEEE Open J. Antennas Propag.

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Implantable bioelectronic devices predominantly use wireless links for communication and/or power transfer. When considering transmitting implanted antennas, electromagnetic radiation through biological media is highly attenuated, and previous work has shown that the in-body path loss can be separated into three parts: the losses incurred by the propagating fields, the reflections at media interfaces, and the coupling of the antenna reactive near field and the lossy body. The first two are unavoidable, but a careful antenna design should minimize the near-field losses. Thus, quantifying the near-field losses of implanted antennas is useful in selecting the antenna topology for preliminary design. The aim of this paper is to present a simplified model of an implanted antenna that provides closed-form approximate expressions to estimate EM radiation from the implant. In particular, we extend the expressions for the reactive near-field losses to both deep and shallow implants, by taking into account the implantation depth. Additionally, the proposed approximate method is verified by comparing the results obtained with the full-wave simulations in the case of a miniature implanted antenna, and with both simulated and measured results from two practical examples found in the literature.INDEX TERMS Implanted antennas, in-body path loss, reactive near field, lossy medium.

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Wireless, Battery-Free, and Fully Implantable Micro-Coil System for 7 T Brain MRI

Cited by 13 publications

References 47 publications

Applications of Microwaves in Medicine

Applications of Microwaves in Medicine

Wireless, customizable coaxially shielded coils for magnetic resonance imaging

Analytic Approximation of In-Body Path Loss for Implanted Antennas

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