scholarly journals A numerical study of pre-polarisation switching in ultra-low field magnetic resonance imaging using dynamic permanent magnet arrays

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Ruben Pellicer-Guridi ◽  
Michael W. Vogel ◽  
Viktor Vegh ◽  
Jiasheng Su ◽  
Matthew S. Rosen ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Permanent Magnet ◽  
Structural Integrity ◽  
Numerical Study ◽  
Human Head ◽  
Von Mises Stress ◽  
Resonance Imaging ◽  
Polarisation Field ◽  
Low Field

Abstract Dynamically adjustable permanent magnet arrays have been proposed to generate switchable magnetic fields for pre-polarisation in Ultra-Low Field magnetic resonance imaging. However, the optimal switching dynamics of the pre-polarisation magnetic field as well as the energy requirements, mechanical forces and stresses during switching of the pre-polarisation field have not been evaluated. We analysed these requirements numerically and estimated the magnetic resonance signal strength and image quality for two practical switching modes in an instrument suitable for scanning the human head. Von Mises stress analysis showed that although magnetic forces were significantly higher for two specific rungs, the structural integrity of magnet rungs would not be compromised. Our simulations suggest that a significantly higher signal yield is obtained by switching off the pre-polarisation field with the angular velocity in each rung dependent on its location.

APPEARANCE OF CANINE ABDOMINAL TUMORS WITH MAGNETIC RESONANCE IMAGING USING A LOW FIELD PERMANENT MAGNET

1997 ◽  
Vol 38 (6) ◽  
pp. 444-447 ◽  
Author(s):  
Janet S. Muleya ◽  
Yasuho Taura ◽  
Munekazu Nakaichi ◽  
Sanenori Nakama ◽  
Akira Takeuchi
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Permanent Magnet ◽  
Resonance Imaging ◽  
Abdominal Tumors ◽  
Low Field

scholarly journals Effectiveness of low-field magnetic resonance imaging in diagnosing brachial plexus tumours in dogs – short communication

2015 ◽  
Vol 59 (2) ◽  
pp. 317-319
Author(s):  
Zbigniew Adamiak ◽  
Yauheni Zhalniarovich ◽  
Paulina Przyborowska ◽  
Joanna Głodek ◽  
Adam Przeworski
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Brachial Plexus ◽  
Resonance Imaging ◽  
Gadolinium Contrast ◽  
Gadolinium Contrast Agent ◽  
Low Field ◽  
Mri Sequences ◽  
Magnetic Resonance Imaging Mri ◽  
Brachial Plexus Tumours

AbstractThe aim of the study was to identify magnetic resonance imaging (MRI) sequences that contribute to a quick and reliable diagnosis of brachial plexus tumours in dogs. The tumours were successfully diagnosed in 6 dogs by the MRI with the use of SE, FSE, STIR, Turbo 3 D, 3D HYCE, and GE sequences and the gadolinium contrast agent

scholarly journals Structural disconnectivity in schizophrenia: a diffusion tensor magnetic resonance imaging study

2003 ◽  
Vol 182 (5) ◽  
pp. 439-443 ◽  
Author(s):  
J. Burns ◽  
D. Job ◽  
M. E. Bastin ◽  
H. Whalley ◽  
T. Macgillivray ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
White Matter ◽  
Magnetic Resonance ◽  
Fractional Anisotropy ◽  
Structural Integrity ◽  
Diffusion Tensor ◽  
Uncinate Fasciculus ◽  
Arcuate Fasciculus ◽  
Resonance Imaging ◽  
White Matter Tracts

BackgroundThere is growing evidence that schizophrenia is a disorder of cortical connectivity Specifically, frontotemporal and frontoparietal connections are thought to be functionally impaired. Diffusion tensor magnetic resonance imaging (DT–MRI) is a technique that has the potential to demonstrate structural disconnectivity in schizophrenia.AimsTo investigate the structural integrity of frontotemporal and frontoparietal white matter tracts in schizophrenia.MethodThirty patients with DSM–IV schizophrenia and thirty matched control subjects underwent DT–MRI and structural MRI. Fractional anisotropy – an index of the integrity of white matter tracts – was determined in the uncinate fasciculus, the anterior cingulum and the arcuate fasciculus and analysed using voxel-based morphometry.ResultsThere was reduced fractional anisotropy in the left uncinate fasciculus and left arcuate fasciculus in patients with schizophrenia compared with controls.ConclusionsThe findings of reduced white matter tract integrity in the left uncinate fasciculus and left arcuate fasciculus suggest that there is frontotemporal and frontoparietal structural disconnectivity in schizophrenia.

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