MRI Technology: Circuits and Challenges for Receiver Coil Hardware

Zanche, Nicola De

doi:10.1002/9780470451816.ch9

Cited by 4 publications

(4 citation statements)

References 25 publications

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“…For example, OBI such as optical fluorescent microscopy can achieve high resolution and high sensitivity, − however, it is limited by poor tissue penetration and three-dimension imaging capability. MRI, however, offers high soft-tissue contrast and excellent tissue-penetration characteristics while lacking high sensitivity. , Consequently, it is advantageous to use a combination of various medical imaging techniques for accurate clinical diagnosis. In such cases, multimodal contrast agents offer reduced costs and enhanced safety by limiting the number of contrast agents administrations and improving overall patient care. , …”

mentioning

confidence: 99%

Porous Upconversion Nanostructures as Bimodal Biomedical Imaging Contrast Agents

Gupta

Clarke

et al. 2020

J. Phys. Chem. C

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Lanthanide ion doped upconversion nanoparticles (UCNPs) hold great promise as multimodal contrast agents for a range of medical imaging techniques, including optical bioimaging (OBI), magnetic resonance imaging (MRI), and computed tomography (CT). However, it is challenging to obtain UCNPs with both maximal contrast enhancement effects for both OBI and MRI simultaneously owing to the dilemma in the size of UCNPs. UCNPs in large dimensions contain more photonic Ln ions and less surface defects, which is favored for high luminescent emissions, while small UCNPs with high specific surface areas allow a higher proportion of paramagnetic Ln ions to be more accessible to water molecules, which offers enhanced contrast in MRI. In this work, we report the novel design of core−porous shell UCNPs with both high luminescent emissions and magnetic relaxivities as potential dual-modal contrast agents. The core–porous shell UCNPs were fabricated via the selective etching of the inert shell of NaYF4: 30%Gd at the active core of NaYF4: 20%Yb, 1%Er. Their morphology and composition were carefully characterized using transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy, X-ray diffraction, and high resolution TEM. Their photoluminescent and magnetic resonance properties were experimentally determined and compared for the core, core–dense shell, and core–porous shell UCNPs. Core–porous shell UCNPs were found to display bright luminescence and superior MRI contrast enhancement, thus showing great potential as bimodal OBI and MRI contrast agents.

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confidence: 99%

Porous Upconversion Nanostructures as Bimodal Biomedical Imaging Contrast Agents

Gupta

Clarke

et al. 2020

J. Phys. Chem. C

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“…An evident remedy against high data rate and storage requirements is data compression, which can be realized in the analog domain by means of down-conversion before digitization as described above and/or in the digital domain, which requires dedicated signal processing units on-coil (e.g., a field-programmable gate array (FPGA) and digital frequency synthesizer [40]). Digital strategies for DR compression and coilwise demodulation can be combined to efficiently reduce the data size to one-third of the original amount [41].…”

Section: Data Ratementioning

confidence: 99%

Perspectives in Wireless Radio Frequency Coil Development for Magnetic Resonance Imaging

et al. 2020

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This paper addresses the scientific and technological challenges related to the development of wireless radio frequency (RF) coils for magnetic resonance imaging (MRI) based on published literature together with the authors' interpretation and further considerations. Key requirements and possible strategies for the wireless implementation of three important subsystems, namely the MR receive signal chain, control signaling, and on-coil power supply, are presented and discussed. For RF signals of modern MRI setups (e.g., 3 T, 64 RF receive channels), with on-coil digitization and advanced methods for dynamic range (DR ≥ 16-bit) and data rate compression, still data rates > 500 Mbps will be required. For wireless high-speed MR data transmission, 60 GHz WiGig and optical wireless communication appear to be suitable strategies; however, on-coil functionality during MRI scans remains to be verified. Besides RF signals, control signals for on-coil components, e.g., active detuning, synchronization to the MR system, and B 0 shimming, have to be managed. Wireless power supply becomes an important issue, especially with a large amount of additional on-coil components. Wireless power transfer systems (>10 W) seem to be an attractive solution compared to bulky MR-compatible batteries and energy harvesting with low power output. In our opinion, completely wireless RF coils will ultimately become feasible in the future by combining efficient available strategies from recent scientific advances and novel research. Besides ongoing improvement of all three subsystems, innovations are specifically required regarding wireless technologies, MR compatibility, and wireless power supply.

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“…Several groups have explored wireless patient coils as a way to avoid the cabling issues, with many focusing on the challenge of how to transmit data from the MRI receive coil. 6,[9][10][11][12][13] Preliminary methods of wireless phase synchronization and gating have been demonstrated. [14][15][16][17] An additional challenge with wireless coils is powering them inside the MRI.…”

Section: Introductionmentioning

confidence: 99%

“…For wireless MRI arrays to be realized, a system must be developed for wireless data, wireless gating, wireless phase synchronization and wireless power transfer. Several groups have explored wireless patient coils as a way to avoid the cabling issues, with many focusing on the challenge of how to transmit data from the MRI receive coil [6], [9]–[13]. Preliminary methods of wireless phase synchronization and gating have been demonstrated [14]–[17].…”

Section: Introductionmentioning

confidence: 99%

An RF‐gated wireless power transfer system for wireless MRI receive arrays

Byron

Robb²,

Stang³

et al. 2017

Concepts Magn Reson

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In MRI systems, cable-free receive arrays would simplify setup while reducing the bulk and weight of coil arrays and improve patient comfort and throughput. Since battery power would limit scan time, wireless power transfer (WPT) is a viable option to continuously supply several watts of power to on-coil electronics. To minimize added noise and decouple the wireless power system from MRI coils, restrictions are placed on the coil geometry of the wireless power system, which are shown to limit its efficiency. Continuous power harvesting can also cause a large increase in the background noise of the image due to diode rectifier up-conversion of noise around the frequency of the transmitted power. However, by RF gating the transmitted power off during the MRI receive time while continuing to supply power from a storage capacitor, WPT is demonstrated to have minimal impact on image quality at received power levels up to 11 W. The integration of WPT with a 1.5T scanner is demonstrated.

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MRI Technology: Circuits and Challenges for Receiver Coil Hardware

Cited by 4 publications

References 25 publications

Porous Upconversion Nanostructures as Bimodal Biomedical Imaging Contrast Agents

Porous Upconversion Nanostructures as Bimodal Biomedical Imaging Contrast Agents

Perspectives in Wireless Radio Frequency Coil Development for Magnetic Resonance Imaging

An RF‐gated wireless power transfer system for wireless MRI receive arrays

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