A complete digital magnetic resonance imaging (MRI) system at low magnetic field (0.1 Tesla)

2003 ◽  
Author(s):  
K. Raoof ◽  
A. Asfour ◽  
J.M. Fournier
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Field ◽  
Magnetic Resonance ◽  
Resonance Imaging ◽  
Magnetic Resonance Imaging Mri ◽  
Low Magnetic Field

scholarly journals B0-Shimming Methodology for Affordable and Compact Low-Field Magnetic Resonance Imaging Magnets

2021 ◽  
Vol 9 ◽  
Author(s):  
Konstantin Wenzel ◽  
Hazem Alhamwey ◽  
Tom O’Reilly ◽  
Layla Tabea Riemann ◽  
Berk Silemek ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Field ◽  
Magnetic Resonance ◽  
Point Of Care ◽  
Low Cost ◽  
Field Measurements ◽  
Target Volume ◽  
Resonance Imaging ◽  
Low Field ◽  
Magnetic Resonance Imaging Mri

Low-field (B0 < 0.2 T) magnetic resonance imaging (MRI) is emerging as a low cost, point-of-care alternative to provide access to diagnostic imaging technology even in resource scarce environments. MRI magnets can be constructed based on permanent neodymium-iron-boron (NdFeB) magnets in discretized arrangements, leading to substantially lower mass and costs. A challenge with these designs is, however, a good B0 field homogeneity, which is needed to produce high quality images free of distortions. In this work, we describe an iterative approach to build a low-field MR magnet based on a B0-shimming methodology using genetic algorithms. The methodology is tested by constructing a small bore (inner bore diameter = 130 mm) desktop MR magnet (<15 kg) at a field strength of B0 = 0.1 T and a target volume of 4 cm in diameter. The configuration consists of a base magnet and shim inserts, which can be placed iteratively without modifying the base magnet assembly and without changing the inner dimensions of the bore or the outer dimensions of the MR magnet. Applying the shims, B0 field inhomogeneity could be reduced by a factor 8 from 5,448 to 682 ppm in the target central slice of the magnet. Further improvements of these results can be achieved in a second or third iteration, using more sensitive magnetic field probes (e.g., nuclear magnetic resonance based magnetic field measurements). The presented methodology is scalable to bigger magnet designs. The MR magnet can be reproduced with off-the-shelf components and a 3D printer and no special tools are needed for construction. All design files and code to reproduce the results will be made available as open source hardware.

A trail of artificial vestibular stimulation: electricity, heat, and magnet

2012 ◽  
Vol 108 (1) ◽  
pp. 1-4 ◽  
Author(s):  
Aasef G. Shaikh
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Field ◽  
Magnetic Resonance ◽  
Semicircular Canals ◽  
Vestibular Stimulation ◽  
Clinical Neurology ◽  
Ion Currents ◽  
Resonance Imaging ◽  
Magnetic Resonance Imaging Mri ◽  
The Magnetic Field

The interaction between the magnetic field of a magnetic resonance imaging (MRI) machine and ion currents within the inner-ear endolymph results in a Lorentz force. This force produces a pressure that pushes on the cupula within the semicircular canals causing nystagmus and vertigo. Here I discuss several implications of this unique and noninvasive way to stimulate the vestibular system in experimental neurophysiology and clinical neurology.

Fabrication of multifunctional ferric oxide nanoparticles for tumor-targeted magnetic resonance imaging and precise photothermal therapy with magnetic field enhancement

2017 ◽  
Vol 5 (43) ◽  
pp. 8554-8562 ◽  
Author(s):  
Jiaxin Liu ◽  
Hongda Chen ◽  
Yu Fu ◽  
Xiaodong Li ◽  
Yixin Chen ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Field ◽  
Magnetic Resonance ◽  
Photothermal Therapy ◽  
Field Enhancement ◽  
Resonance Imaging ◽  
System P ◽  
Weighted Magnetic Resonance Imaging ◽  
Magnetic Resonance Imaging Mri ◽  
Magnetic Field Enhancement

Fe2O3@PDA-affibody integrates T2-weighted magnetic resonance imaging (MRI), tumor-targeting, and magnetic field (MF)-enhanced photothermal therapy (PTT) functionalities into an all-in-one system.

Magnetic Resonance Imaging of Hematomas in a 0.02 T Magnetic Field

1986 ◽  
Vol 27 (5) ◽  
pp. 589-593 ◽  
Author(s):  
A. Alanen
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Field ◽  
Relaxation Time ◽  
Magnetic Resonance ◽  
Pulse Sequence ◽  
Spin Echo ◽  
Imaging Modalities ◽  
Resonance Imaging ◽  
Inversion Time ◽  
Low Magnetic Field

One intramuscular calf hematoma, 2 ankle hematomas and 4 cephalhematomas were imaged at various ages in a low magnetic field (0.02 T). At least one spin echo (SE) multislice image and a series of inversion recovery images (IR) were made varying the inversion time for estimation of the relaxation time T1. T1 tended to shorten and T2 to stay unchanged. With an unsuitable pulse sequence the hematomas were not visible. They were best seen with short TIs. The images of one of the ankle hematomas and the calf hematoma were compared with sonographic findings. The appearances of the hematomas varied during aging with both imaging modalities. The hematomas were easier to detect with magnetic resonance imaging than with ultrasound, also when aging.

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