Measurement of Magnetic Resonance Signal from a Rat Head in Ultra-Low Magnetic Field

Oyama, Daisuke; Higuchi, Masanori; Kawai, Jun; Tsuyuguchi, Naohiro; Miyamoto, Masatoshi; Adachi, Yoshiaki; Uehara, Gen

doi:10.1109/isec.2015.7383470

Cited by 4 publications

(3 citation statements)

References 8 publications

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“…The MEG signals from the MEG‐MRI hybrid was also compared with a commercial MEG device from Elekta Oy (Helsinki, Finland) and were found to be highly correlated. Oyama et al have also demonstrated a similar SQUID MEG‐ULF‐MRI measurement of a rat head …”

Section: Current State Of the Artmentioning

confidence: 77%

“…Oyama et al have also demonstrated a similar SQUID MEG-ULF-MRI measurement of a rat head. 56 The effect of magnetic field fluctuation in unshielded urban environments on the operation of ULF-MRI has been investigated by Liu et al 57 The authors demonstrate the severe, moderate, and minute fluctuations that occur during day and night times. Importantly, they also propose and show the improvement of ULF-MRI performance through active compensation based on spatial correlation of low-frequency fluctuations.…”

Section: Ulf Mri (<10 Mt)mentioning

confidence: 99%

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Accessible magnetic resonance imaging: A review

Geethanath

Vaughan

2019

Magnetic Resonance Imaging

140

139

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The role of MRI in diagnostics, prognostics, and discoveries in basic sciences has been well established. However, access to this life‐saving technology is largely restricted to countries in upper‐middle to high‐income groups. In this article, we collate recent global MR scanner density data and group them into six geographical regions based on the WHO classification. We then analyze these data with respect to demographic factors such as population size, life expectancy, the percentage of internet users, and World Bank income grouping. We map these demographic factors to five dimensions or characteristics of accessible MRI, adapting definitions from the healthcare literature. With this background, the study then reviews recent demonstrations of accessible MRI categorized based on main magnetic field strength. We describe demonstrated examples for each of these categories, ranging from ultralow‐field to ultrahigh‐field MRI. Lastly, we review MR methods and associated developments impacting accessible MRI such as increasing/augmenting MR awareness and local expertise, incorporating hardware‐cognizant methods, rapid quantitative imaging, and leveraging innovations from adjacent fields. Level of Evidence: 5 Technical Efficacy Stage: 6 J. Magn. Reson. Imaging 2019.

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Section: Current State Of the Artmentioning

confidence: 77%

Section: Ulf Mri (<10 Mt)mentioning

confidence: 99%

Accessible magnetic resonance imaging: A review

Geethanath

Vaughan

2019

Magnetic Resonance Imaging

140

139

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“…Several research groups have developed SQUID-based ULF-MRI systems using magnetic fields ranging from tens of T to 200 T to capture human head MR image 8) -14) . We also developed a ULF-MRI system to combine small-animal MEG with a B0 of 33 T 15), 16) . In these ULF-MRI systems, a pre-polarization technique that applies a magnetic field pulse (Bp-pulse) to the samples or subjects was used to increase the amplitude of the MR signal.…”

Section: Introductionmentioning

confidence: 99%

Development of Ultra-Low Field Magnetic Resonance Imaging System at 1 mT

et al. 2023

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Ultra-low field (ULF) magnetic resonance imaging (MRI) is considered an innovative MRI technique that can be combined with magnetoencephalography (MEG). In this study, a 1-mT ULF-MRI system without a pre-polarization technique aiming at combining an MEG system is developed. The intensity of the static magnetic field B0 is decided considered to be 1 mT because of the limitation of the magnetic field exposed to our MEG sensor made of superconducting quantum interference devices (SQUIDs). A square-shaped (750 mm × 750 mm) B0-coil based on a Merritt-type configuration is fabricated. The inhomogeneity of B0 is less than 0.07 % in the ±125 mm area. Further, an induction coil is employed to detect the magnetic resonance signal instead of the SQUID sensors of the MEG to confirm the feasibility of realizing MRI measurement at 1 mT without the pre-polarization technique. Relaxation time measurements and MR imaging of a phantom made of a CuSO4 aqueous solution are performed. Reasonable longitudinal and transverse relaxation times are obtained, and clear shapes of the phantom are obtained using the gradient-and spin-echo pulse sequences with this ULF-MRI system. These results indicate the potential of the proposed 1-mT ULF-MRI to effectively integrate ULF-MRI and MEG systems without pre-polarization.

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