SQUID-based systems for co-registration of ultra-low field nuclear magnetic resonance images and magnetoencephalography

Matlashov, Andrei; Burmistrov, E. V.; Magnelind, Per E.; Schultz, L.; Urbaitis, Algis V.; Volegov, P. L.; Yoder, Jacob; Espy, Michelle A.

doi:10.1016/j.physc.2012.04.028

Cited by 24 publications

(14 citation statements)

References 20 publications

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“…Clarke et al presented highresolution images of phantoms and bell peppers in ULF of 132 μT [18,22]. Moreover, they also acquired images of the human brain based on the ULF MRI system operating in a magnetic field of 130 μT [23,24]. Espy et al constructed images from many kinds of samples including the human brain, human hand, liquid explosives, and water by SQUID in microtesla magnetic fields, and the resolution was sufficient to reveal anatomical features [25,26].…”

Section: Introductionmentioning

confidence: 99%

SQUID-Based Magnetic Resonance Imaging at Ultra-Low Field Using the Backprojection Method

Guo

Zhang

et al. 2020

Concepts in Magnetic Resonance Part B, Magnetic Resonance Engin

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Ultra-low field magnetic resonance imaging (ULF MRI) is an effective imaging technique that applies the ultrasensitive detector of superconducting quantum interference device (SQUID) sensor to detect the MR signal at a microtesla field range. In this work, we designed and developed a SQUID-based ULF MRI system with a frequency-adjustable measurement field, the performance of which was characterized via water phantoms. In order to enhance the MR signals, a 500 mT Halbach magnet was used to prepolarize the magnetization of the sample prior to excitation. The signal-to-noise-ratio (SNR) of the spin-echo- (SE-) based pulse sequence can reach up to 70 in a single scan. The images were then reconstructed successfully by using the maximum likelihood expectation maximization (MLEM) algorithm based on the backprojection imaging method. It was demonstrated that an in-plane resolution of 1.8 × 1.8 mm2 can be achieved which indicated the feasibility of SQUID-based MRI at the ULF.

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Section: Introductionmentioning

confidence: 99%

SQUID-Based Magnetic Resonance Imaging at Ultra-Low Field Using the Backprojection Method

Guo

Zhang

et al. 2020

Concepts in Magnetic Resonance Part B, Magnetic Resonance Engin

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“…3 Many applications of low-field NMR have been reported in oil well logging, [4][5][6] food characterization, 7,8 quality control 9 and medical imaging. [10][11][12][13][14] As commercially available arbitrary waveform generators (AWG's) and digitizers have become cheaper and more powerful, constructing a low-field NMR instrument has become feasible for laboratories without dedicated electrical engineering support.…”

Section: Introductionmentioning

confidence: 99%

“…In ultra‐low magnetic fields (<1 mT) magnetic susceptibility becomes a trivial issue as demonstrated by the collection of distortion free NMR/MRI through an aluminum can . Many applications of low‐field NMR have been reported in oil well logging, food characterization, quality control and medical imaging . As commercially available arbitrary waveform generators (AWG's) and digitizers have become cheaper and more powerful, constructing a low‐field NMR instrument has become feasible for laboratories without dedicated electrical engineering support.…”

Section: Introductionmentioning

confidence: 99%

Characterization of a PXIe based low‐field digital NMR spectrometer

Biller

Stupic

Kos

et al. 2017

Concepts Magn Reson

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A low‐field nuclear magnetic resonance (NMR) instrument is an important tool for investigating a wide variety of samples under different conditions. In this paper, we describe a system constructed primarily with commercially available hardware and control software, capable of single‐pulse NMR experiments. Details of the construction of the main B0 magnet are also included. The operating frequency for demonstration is 460 kHz (10 mT), however, the range of the hardware spans 700 Hz (16 μT) to 25 MHz (0.6 T). Tip angle optimizations are used to find the most narrow usable pulse width for this configuration, and the T1 of water is measured by single‐pulse‐saturation‐recovery (SPSR) to demonstrate the potential for this system as a relaxometer. Discussions of resonator construction and efficiency, power requirements and programming strategies that would increase the utility of this system are also included. Construction of any low‐field NMR system will depend on experimental interests, budget and engineering resources. A survey of other low‐field NMR systems from the literature is included to aid the novice or experienced magnetic resonance scientist in consideration of how a low‐field spectrometer could be constructed and used in the lab.

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“…They are less sensitive to the presence of metals [ 4 ], thus opening the technique to patients with metallic implants. Furthermore, VLF and ULF devices allow integration of MRI with other imaging modalities whose hardware is not compatible with high magnetic fields, such as Magnetoencephalography (MEG) [ 5 , 6 , 7 ]. Nevertheless, despite these advantages, they are not commercially available since they do not guarantee, at the moment, the imaging quality to be considered as a valid tool for clinical practice.…”

Section: Introductionmentioning

confidence: 99%

Fast Room Temperature Very Low Field-Magnetic Resonance Imaging System Compatible with MagnetoEncephaloGraphy Environment

et al. 2015

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In recent years, ultra-low field (ULF)-MRI is being given more and more attention, due to the possibility of integrating ULF-MRI and Magnetoencephalography (MEG) in the same device. Despite the signal-to-noise ratio (SNR) reduction, there are several advantages to operating at ULF, including increased tissue contrast, reduced cost and weight of the scanners, the potential to image patients that are not compatible with clinical scanners, and the opportunity to integrate different imaging modalities. The majority of ULF-MRI systems are based, until now, on magnetic field pulsed techniques for increasing SNR, using SQUID based detectors with Larmor frequencies in the kHz range. Although promising results were recently obtained with such systems, it is an open question whether similar SNR and reduced acquisition time can be achieved with simpler devices. In this work a room-temperature, MEG-compatible very-low field (VLF)-MRI device working in the range of several hundred kHz without sample pre-polarization is presented. This preserves many advantages of ULF-MRI, but for equivalent imaging conditions and SNR we achieve reduced imaging time based on preliminary results using phantoms and ex-vivo rabbits heads.

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SQUID-based systems for co-registration of ultra-low field nuclear magnetic resonance images and magnetoencephalography

Cited by 24 publications

References 20 publications

SQUID-Based Magnetic Resonance Imaging at Ultra-Low Field Using the Backprojection Method

SQUID-Based Magnetic Resonance Imaging at Ultra-Low Field Using the Backprojection Method

Characterization of a PXIe based low‐field digital NMR spectrometer

Fast Room Temperature Very Low Field-Magnetic Resonance Imaging System Compatible with MagnetoEncephaloGraphy Environment

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