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Result : Searchterm 'View' found in 5 terms [] and 99 definitions []
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Searchterm 'View' was also found in the following services: 
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News  (56)  Resources  (52)  Forum  (50)  
 
Radio Frequency Overflow ArtifactInfoSheet: - Artifacts - 
Case Studies, 
Reduction Index, 
etc.MRI Resource Directory:
 - Artifacts -
 
Quick Overview
Please note that there are different common names for this artifact.
Artifact Information
NAME
Radio frequency overflow, data clipping
DESCRIPTION
Image non-uniform
REASON
Signal too intense
HELP
Manually decrease of the receiver gain
The received radio frequency signal is too strong, parts of the signal get lost by converting from analog to digital, resulting in a washed out image.
mri safety guidance
Image Guidance
Auto-prescanning usually adjusts the amplification at the receiver in a way, that the received signal could be processed without any loss. Else the receiver gain must be corrected manually.

See also Data Clipping Artifact, Artifact Overview and Artifacts Reduction Index.
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Further Reading:
  Basics:
RF Overflow Artifacts
   by www.mritutor.org    
  News & More:
Magnetic Resonance Imaging (MRI)
2003   by www.hull.ac.uk    
Searchterm 'View' was also found in the following services: 
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Radiology  (40) Open this link in a new windowUltrasound  (50) Open this link in a new window
Radio Frequency Quadrature ArtifactInfoSheet: - Artifacts - 
Case Studies, 
Reduction Index, 
etc.MRI Resource Directory:
 - Artifacts -
 
Quick Overview
Artifact Information
NAME
Radio frequency quadrature
DESCRIPTION
Bright spot in the center of the image, ghosting
REASON
RF detection circuitry problem
HELP
Call the service
Radio frequency quadrature artifacts occur when the detector channels of the quadrature detector are disturbed.
A DC offset of one amplifier output can e.g., produce a bright point in the center of the field of view (see also central point artifact), or a higher gain of one detector channel can generate diagonally ghosting.
mri safety guidance
Image Guidance
Radio frequency quadrature artifacts are technical faults and must be eliminated by the service.
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Further Reading:
  News & More:
Magnetic Resonance Imaging (MRI)
2003   by www.hull.ac.uk    
MRI Resources 
Service and Support - Process Analysis - Anatomy - Mobile MRI Rental - Shielding - MRI Centers
 
Signal to Noise Ratio
 
(SNR or S/N) The signal to noise ratio is used in MRI to describe the relative contributions to a detected signal of the true signal and random superimposed signals ('background noise') - a criterion for image quality.
One common method to increase the SNR is to average several measurements of the signal, on the expectation that random contributions will tend to cancel out. The SNR can also be improved by sampling larger volumes (increasing the field of view and slice thickness with a corresponding loss of spatial resolution) or, within limits, by increasing the strength of the magnetic field used. Surface coils can also be used to improve local signal intensity. The SNR will depend, in part, on the electrical properties of the sample or patient being studied. The SNR increases in proportion to voxel volume (1/resolution), the square root of the number of acquisitions (NEX), and the square root of the number of scans (phase encodings). SNR decreases with the field of view squared (FOV2) and wider bandwidths. See also Signal Intensity and Spin Density.

Measuring SNR:
Record the mean value of a small ROI placed in the most homogeneous area of tissue with high signal intensity (e.g. white matter in thalamus). Calculate the standard deviation for the largest possible ROI placed outside the object in the image background (avoid ghosting/aliasing or eye movement artifact regions).
The SNR is then:
Mean Signal/Standard Deviation of Background Noise
 
Images, Movies, Sliders:
 Brain MRI Images T1  Open this link in a new window
      

 
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• View the DATABASE results for 'Signal to Noise Ratio' (48).Open this link in a new window


• View the NEWS results for 'Signal to Noise Ratio' (2).Open this link in a new window.
 
Further Reading:
  Basics:
Musculoskeletal MRI at 3.0 T: Relaxation Times and Image Contrast
Sunday, 1 August 2004   by www.ajronline.org    
  News & More:
Picture-Perfect Particles Enhance MRI Signal
Friday, 13 April 2012   by cen.acs.org    
Researchers design 'intelligent' metamaterial to make MRIs affordable and accessible
Tuesday, 5 November 2019   by phys.org    
Metamaterials boost sensitivity of MRI machines
Thursday, 14 January 2016   by www.eurekalert.org    
Optimizing Musculoskeletal MR
   by rad.usuhs.mil    
Searchterm 'View' was also found in the following services: 
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News  (56)  Resources  (52)  Forum  (50)  
 
Virgoâ„¢InfoSheet: - Devices -
Intro, 
Types of Magnets, 
Overview, 
etc.MRI Resource Directory:
 - Devices -
 
www.canamglobal.com/mri/virgomri.html From Millennium Technology Inc. This open C-shaped MRI system eases patient comfort and technologist maneuverability. This low cost scanner is build for a wide range of applications. The Virgo™ patient table is detachable and moves on easy rolling castors. Able to accommodate patient weights up to 160 kg, the tabletop has a range of motion of 30 cm in the lateral direction and 90cm in the longitudinal direction. Images generated with this scanner can only be viewed (without data loss) on Millennium's proprietary viewing software.
Device Information and Specification
CLINICAL APPLICATION
Whole body
CONFIGURATION
C shaped
SYNCHRONIZATION
Standard cardiac gating, ECG/peripheral, respiratory gating
PULSE SEQUENCES
2D Spin Echo (single and multi-echo), 2D Inversion Recovery, 2D Sequential and 3D Volume Gradient Echo, 2D and 3D Spoiled Gradient Echo
IMAGING MODES
Localizer, single slice, multislice, volume, fast, POMP, multi slab, cine, slice and frequency zip, extended dynamic range, tailored RF
TR
steps of 1 msec
TE
steps of 1 msec
SINGLE/MULTI SLICE
Simultaneous scan and reconstruction;; 100 images/second reconstruction
400 mm
2D : 2 mm; 3D : 0.5 mm
MEASURING MATRIX
512x512
PIXEL INTENSITY
256 gray levels
MAGNET TYPE
Permanent
BORE DIAMETER
or Vertical Gap
44 cm
STRENGTH
15 mT/m
5-GAUSS FRINGE FIELD
3 m/3 m
Passive
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Searchterm 'View' was also found in the following services: 
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Radiology  (40) Open this link in a new windowUltrasound  (50) Open this link in a new window
Wrap Around ArtifactInfoSheet: - Artifacts - 
Case Studies, 
Reduction Index, 
etc.MRI Resource Directory:
 - Artifacts -
 
A wrap around artifact (also called backfolding artifact or aliasing artifact) is produced by inadequate sampling or digitization. Wrap around artifacts result from digitizing fewer than two samples per period in a periodic function. Aliasing can occur in MR imaging whenever the scanned area extends beyond the field of view. These areas extending beyond the field of view boundaries are aliased back into the image to appear at artifactual locations.
 
Images, Movies, Sliders:
 Breast MRI Transverse T1 Pre Contrast 001  Open this link in a new window
    
 
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• View the DATABASE results for 'Wrap Around Artifact' (3).Open this link in a new window

 
Further Reading:
  Basics:
Aliasing or wrap around artifacts
Thursday, 31 March 2011   by de.slideshare.net    
MRI Resources 
Guidance - MRI Training Courses - Online Books - NMR - Portals - Chemistry
 
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