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Result : Searchterm 'Gradient' found in 59 terms [] and 252 definitions []
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GradientForum -
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The word gradient (from grade) means the inclination of a surface along a given direction. In MRI, gradient stands for gradient field and/or gradient coil. Inside the main magnet are three gradient coils located, which produce the desired gradient (magnetic) fields. These fields are used to alter (collectively and sequentially) the influence of the static magnetic field B0 on the imaged object by inc- or decreasing the field strength and changing the direction. Through this influence selective spatial excitation and spatial encoding (each voxel resonate at a different frequency) is possible. Gradients are also utilized in another way for fast imaging sequences.
See also Slew Rate and Duty Cycle.
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Further Reading:
  Basics:
Motion Compensation in MR Imaging
   by ccn.ucla.edu    
Active Noise Control of Magnetic Resonance Imaging Scanner Using Inverse Modeling Technique
Monday, 19 April 2010   by www.acoustics.org    
Artifacts in MRI
Saturday, 1 October 2011   by www.huc.min-saude.pt    
  News & More:
On the Horizon - Next Generation MRI
Wednesday, 23 October 2013   by thefutureofthings.com    
Searchterm 'Gradient' was also found in the following services: 
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Gradient CoilForum -
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Current carrying coils designed to produce a desired magnetic field gradient (so that the magnetic field will be stronger in some locations than others).
Proper design of the size and configuration of the coils is necessary to produce a controlled and uniform gradient. Three paired orthogonal current-carrying coils located within the magnet that are designed to produce desired gradient magnetic fields, which collectively and sequentially are superimposed on the main magnetic field (B0) so that selective spatial excitation of the imaging volume can occur.
Gradients are also used to apply reversal pulses in some fast imaging techniques. Gradient coils in general vary the main magnetic field, so that each signal can be related to an exact location. The gradient coil configuration for the z-axis consists of e.g., Helmholtz pair coils, and of paired saddle coils for the x- and y-axis.

See also the related poll result: 'Most outages of your scanning system are caused by failure of'
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• View the DATABASE results for 'Gradient Coil' (19).Open this link in a new window

 
Further Reading:
  Basics:
Magnetic Field Simulation of Golay Coil(.pdf)
2008   by eprints.utm.my    
Electrical eddy currents in the human body: MRI scans and medical implants
   by www.phy.olemiss.edu    
HEAD AND NECK MRI GRADIENT COIL DESIGN
Thursday, 26 August 1999   by www.imaging.robarts.ca    
MRI Resources 
Universities - Guidance - Quality Advice - Implant and Prosthesis pool - Education - Claustrophobia
 
Gradient EchoForum -
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(GE) An echo signal generated from a free induction decay by means of a bipolar switched magnetic gradient. The echo is produced by reversing the direction of a magnetic field gradient or by applying balanced pulses of magnetic field gradient before and after a refocusing RF pulse so as to cancel out the position dependent phase shifts that have accumulated due to the gradient.
In the latter case, the gradient echo is generally adjusted to be coincident with the RF spin echo. When the RF and gradient echoes are not coincident, the time of the gradient echo is denoted echo time (TE) and the difference in time between the echoes is denoted time difference (TD).
Gradient echo does not refocus the effects of main field inhomogeneity and therefore is generally used with a short echo time. Disadvantages of gradient echo imaging are compromised anatomic details and artifacts in regions with varying susceptibility e.g. between the air-containing sinuses and brain and especially between haemorrhages and normal tissue.
See also Susceptibility Artifact.
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• View the DATABASE results for 'Gradient Echo' (121).Open this link in a new window

 
Further Reading:
  Basics:
Mapping of low flip angles in magnetic resonance(.pdf)
Saturday, 1 January 2011   by www.hal.inserm.fr    
A LANTHANIDE LANTHOLOGY(.pdf)
   by www.phy.davidson.edu    
Enhanced Fast GRadient Echo 3-Dimensional (efgre3D) or THRIVE
   by www.mri.tju.edu    
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Gradient Swap
 
Flow and motion artifacts are rotated about 90°, caused by the exchange of phase and frequency encoding direction. That prevents artifacts from hiding structures of interest.
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Field Gradient
 
See Magnetic Field Gradient.
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• View the DATABASE results for 'Field Gradient' (32).Open this link in a new window

 
Further Reading:
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Active Noise Control of Magnetic Resonance Imaging Scanner Using Inverse Modeling Technique
Monday, 19 April 2010   by www.acoustics.org    
MRI Resources 
Breast MRI - Spectroscopy pool - MR Myelography - Coils - Stent - MRI Accidents
 
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