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Result : Searchterm 'Artifact' found in 62 terms [] and 104 definitions []
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Searchterm 'Artifact' was also found in the following services: 
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News  (6)  Resources  (10)  Forum  (22)  
 
Black Boundary 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
Black boundary, dark boundary, contour, chemical shift, relief
DESCRIPTION
Black contours at boundaries
Black boundary artifacts are black lines following voxels where both water and fat protons are present in the same voxel. This artifact arise along the boundary of organs or tissues perpendicular to the frequency encoding direction, and occurs preferentially in gradient echo sequences with out of phase echo times.
mri safety guidance
Image Guidance
Fat suppression techniques eliminate this artifact. For artifact reducing helps a smaller water fat shift (high bandwidth), a higher matrix or/and an in phase TE.

See also Chemical Shift Artifact.
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Further Reading:
  Basics:
What is chemical shift artefact? Why does it occur? How many Hz at 1.5 T?
   by www.revisemri.com    
Searchterm 'Artifact' was also found in the following services: 
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Radiology  (4) Open this link in a new windowUltrasound  (60) Open this link in a new window
Cardiac Motion ArtifactInfoSheet: - Artifacts - 
Case Studies, 
Reduction Index, 
etc.MRI Resource Directory:
 - Artifacts -
 
Quick Overview
Artifact Information
NAME
Cardiac motion
DESCRIPTION
Blurring, ghosting
REASON
Cardiac motion
HELP
cardiac and respiratory synchronization
Movement of the heart causes blurring and ghosting in the images. The artifacts appear in the phase encoding direction, independent of the direction of the motion.
mri safety guidance
Image Guidance
These artifacts can be reduced by using cardiac synchronization: triggering, gating or retrospective triggering. Maximum reduction can be achieved by using triggering in combination with flow compensation, respiratory triggering or breath hold and regional saturation techniques.

See also Motion Artifact.
 
Images, Movies, Sliders:
 Cardiac Infarct Short Axis Cine bFFE 1  Open this link in a new window
    
 Normal Dual Inversion Fast Spin-echo  Open this link in a new window
 
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• View the DATABASE results for 'Cardiac Motion Artifact' (2).Open this link in a new window

 
Further Reading:
  Basics:
Motion-compensation of Cardiac Perfusion MRI using a Statistical Texture Ensemble(.pdf)
June 2003   by www.imm.dtu.dk    
  News & More:
Controlling patient's breathing makes cardiac MRI more accurate
Friday, 13 May 2016   by www.upi.com    
MRI Resources 
Intraoperative MRI - Education - Manufacturers - Pregnancy - Guidance - Mobile MRI
 
Chemical Shift 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
Chemical shift, black boundary, spatial misregistration, relief
DESCRIPTION
Black or bright band
During frequency encoding, fat protons precess slower than water protons in the same slice because of their magnetic shielding. Through the difference in resonance frequency between water and fat, protons at the same location are misregistrated (dislocated) by the Fourier transformation, when converting MRI signals from frequency to spatial domain. This chemical shift misregistration cause accentuation of any fat-water interfaces along the frequency axis and may be mistaken for pathology. Where fat and water are in the same location, this artifact can be seen as a bright or dark band at the edge of the anatomy.
Protons in fat and water molecules are separated by a chemical shift of about 3.5 ppm. The actual shift in Hertz (Hz) depends on the magnetic field strength of the magnet being used. Higher field strength increases the misregistration, while in contrast a higher gradient strength has a positive effect. For a 0.3 T system operating at 12.8 MHz the shift will be 44.8 Hz compared with a 223.6 Hz shift for a 1.5 T system operating at 63.9 MHz.
mri safety guidance
Image Guidance
For artifact reduction helps a smaller water fat shift (higher bandwidth), a higher matrix, an in phase TE or a spin echo technique. Since the misregistration offset is present in the read out axis the patient may be rescanned with this axis parallel to the fat-water interface. Steeper gradient may be employed to reduce the chemical shift offset in mm. Another strategy is to employ specialized pulse sequences such as fat saturation or inversion recovery imaging. Fat suppression techniques eliminate chemical shift artifacts caused by the lack of fat signal.

See also Black Boundary Artifact and Magnetic Resonance Spectroscopy.
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• View the DATABASE results for 'Chemical Shift Artifact' (7).Open this link in a new window

 
Further Reading:
  Basics:
MRI Artifact Gallery
   by chickscope.beckman.uiuc.edu    
  News & More:
What is chemical shift artefact? Why does it occur? How many Hz at 1.5 T?
   by www.revisemri.com    
Abdominal MRI at 3.0 T: The Basics Revisited
Wednesday, 20 July 2005   by www.ajronline.org    
Searchterm 'Artifact' was also found in the following services: 
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News  (6)  Resources  (10)  Forum  (22)  
 
Partial Volume ArtifactInfoSheet: - Artifacts - 
Case Studies, 
Reduction Index, 
etc.MRI Resource Directory:
 - Artifacts -
 
Quick Overview
Artifact Information
NAME
Partial volume
DESCRIPTION
Loss of contrast between two adjacent tissues
REASON
Insufficient resolution
HELP
Thinner slices
The Partial Volume Artifact is caused by imaging voxel containing two different tissues and therefore possessing a signal average of both tissues.
mri safety guidance
Image Guidance
Take thinner slices (smaller voxel), but this may result in poorer signal to noise ratio in the image.

See Partial Volume Effect.
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• View the DATABASE results for 'Partial Volume Artifact' (4).Open this link in a new window

 
Further Reading:
  Basics:
MRI GLOSSARY
   by fonar.com    
Searchterm 'Artifact' was also found in the following services: 
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Radiology  (4) Open this link in a new windowUltrasound  (60) Open this link in a new window
Phase Wrapping ArtifactInfoSheet: - Artifacts - 
Case Studies, 
Reduction Index, 
etc.MRI Resource Directory:
 - Artifacts -
 
Parts of the body, which extend beyond the Field of view in the phase encoding direction may still be visible in the image as artifacts.
Please note that aliasing in the frequency direction is also possible but can be eliminated in the same manner or by applying frequency specific filters to the received signal.

See Aliasing Artifact.
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• View the DATABASE results for 'Phase Wrapping Artifact' (2).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 
General - Directories - Implant and Prosthesis - Bioinformatics - Pathology - Movies
 
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