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.

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.

scholarly journals The Zurich Checklist for Safety in the Intraoperative Magnetic Resonance Imaging Suite: Technical Note

2018 ◽  
Vol 16 (6) ◽  
pp. 756-765 ◽  
Author(s):  
Martin N Stienen ◽  
Jorn Fierstra ◽  
Athina Pangalu ◽  
Luca Regli ◽  
Oliver Bozinov
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Field ◽  
Magnetic Resonance ◽  
High Strength ◽  
Technical Note ◽  
Patient Transfer ◽  
Resonance Imaging ◽  
Intraoperative Magnetic Resonance Imaging ◽  
Surgical Checklist ◽  
The Magnetic Field

Abstract BACKGROUND Recently, the use of intraoperative magnetic resonance imaging (ioMRI) has evolved in neurosurgery. Challenges related to ioMRI-augmented procedures are significant, since the magnetic field creates a potentially hazardous environment. Strict safety guidelines in the operating room (OR) are necessary. Checklists can minimize errors while increasing efficiency and improving workflow. OBJECTIVE To describe the Zurich checklists for safety in the ioMRI environment. METHODS We summarize the checklist protocol and the experience gained from over 300 surgical procedures performed over a 4-yr period using this new system for transcranial or transsphenoidal surgery in a 2-room high-field 3 Tesla ioMRI suite. RESULTS Particularities of the 2-room setting used at our institution can be summarized as (1) patient transfer from a sterile to a nonsterile environment and (2) patient transfer from a zone without to a zone with a high-strength magnetic field. Steps on the checklist have been introduced for reasons of efficient workflow, safety pertaining to the strength of the magnetic field, or sterility concerns. Each step in the checklist corresponds to a specific phase and particular actions taken during the workflow in the ioMRI suite. Most steps are relevant to any 2-room ioMRI-OR suite. CONCLUSION The use of an ioMRI-checklist promotes a zero-tolerance attitude for errors, can lower complications, and can help create an environment that is both efficient and safe for the patient and the OR personnel. We highly recommend the use of a surgical checklist when applying ioMRI.

The Magnetic Field of Magnetic Resonance Imaging Systems Does Not Affect Cells Labeled with Micrometer-Sized Iron Oxide Particles

2017 ◽  
Vol 23 (7) ◽  
pp. 412-421 ◽  
Author(s):  
Martin Kluge ◽  
Annekatrin Leder ◽  
Karl H. Hillebrandt ◽  
Benjamin Struecker ◽  
Dominik Geisel ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Field ◽  
Iron Oxide ◽  
Magnetic Resonance ◽  
Imaging Systems ◽  
Resonance Imaging ◽  
Iron Oxide Particles ◽  
Oxide Particles ◽  
The Magnetic Field
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