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Result : Searchterm 'Susceptibility Artifact' found in 1 term [] and 15 definitions [], (+ 5 Boolean[] results
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Searchterm 'Susceptibility Artifact' was also found in the following services: 
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Combination Oral Contrast AgentsInfoSheet: - Contrast Agents - 
Intro, Overview, 
Characteristics, 
Types of, 
etc.MRI Resource Directory:
 - Contrast Agents -
 
Biphasic oral contrast agents may produce either high or low signal intensities depending on the pulse sequence used, for example low signal intensity on T1 weighted MR images and high signal intensity on T2 weighted images. The combination of different oral contrast agents can generate a macroscopic cancellation of negative and positive magnetic susceptibility, thereby eliminating susceptibility artifacts.
Possible combinations are e.g., ferric ammonium citrate and corn oil, or ferrous sulfate emulsified with baby formula. Paramagnetic agents combined with oil emulsion may be used in MRI as positive abdominal contrast agents. The combination of diamagnetic barium sulfate and superparamagnetic iron oxide (SPIO) in one suspension may be a useful negative contrast agent.

See also Gastrointestinal Paramagnetic Contrast Agents, Gastrointestinal Superparamagnetic Contrast Agents, Gastrointestinal Diamagnetic Contrast Agents, Gastrointestinal Imaging.
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Further Reading:
  Basics:
Usefulness of MR Imaging for Diseases of the Small Intestine: Comparison with CT
2000   by www.ncbi.nlm.nih.gov    
MRI Resources 
Movies - Anatomy - Hospitals - Service and Support - Jobs - Directories
 
Fast Imaging with Steady State PrecessionInfoSheet: - Sequences - 
Intro, 
Overview, 
Types of, 
etc.
 
(FISP) A fast imaging sequence, which attempts to combine the signals observed separately in the FADE sequence, generally sensitive about magnetic susceptibility artifacts and imperfections in the gradient waveforms. Confusingly now often used to refer to a refocused FLASH type sequence.
This sequence is very similar to FLASH, except that the spoiler pulse is eliminated. As a result, any transverse magnetization still present at the time of the next RF pulse is incorporated into the steady state. FISP uses a RF pulse that alternates in sign. Because there is still some remaining transverse magnetization at the time of the RF pulse, a RF pulse of a degree flips the spins less than a degree from the longitudinal axis. With small flip angles, very little longitudinal magnetization is lost and the image contrast becomes almost independent of T1. Using a very short TE (with TR 20-50 ms, flip angle 30-45°) eliminates T2* effects, so that the images become proton density weighted. As the flip angle is increased, the contrast becomes increasingly dependent on T1 and T2*. It is in the domain of large flip angles and short TR that FISP exhibits vastly different contrast to FLASH type sequences. Used for T1 orthopedic imaging, 3D MPR, cardiography and angiography.
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Further Reading:
  Basics:
MRI techniques improve pulmonary embolism detection
Monday, 19 March 2012   by medicalxpress.com    
MRI Resources 
Services and Supplies - Safety pool - Implant and Prosthesis pool - Service and Support - Liver Imaging - MRCP
 
Fast Low Angle ShotInfoSheet: - Sequences - 
Intro, 
Overview, 
Types of, 
etc.MRI Resource Directory:
 - Sequences -
 
(FLASH) A fast sequence producing signals called gradient echo with low flip angles. FLASH sequences are modifications, which incorporate or remove the effects of transverse coherence respectively.
FLASH uses a semi-random spoiler gradient after each echo to spoil the steady state (to destroy any remaining transverse magnetization) by causing a spatially dependent phase shift. The transverse steady state is spoiled but the longitudinal steady state depends on the T1 values and the flip angle. Extremely short TR times are possible, as a result the sequence provides a mechanism for gaining extremely high T1 contrast by imaging with TR times as brief as 20 to 30 msec while retaining reasonable signal levels. It is important to keep the TE as short as possible to suppress susceptibility artifacts.
The T1 contrast depends on the TR as well as on flip angle, with short TE.
Small flip angles and short TR results in proton density, and long TR in T2* weighting.
With large flip angles and short TR result T1 weighted images.

TR and flip angle adjustment:

TR 3000 ms, Flip Angle 90°
TR 1500 ms, Flip Angle 45°
TR 700 ms, Flip Angle 25°
TR 125 ms, Flip Angle 10°

The apparent ability to trade TR against flip angle for purposes of contrast and the variation in SNR as the scan time (TR) is reduced.

See also Gradient Echo Sequence.
 
Images, Movies, Sliders:
 Fetus (Brain) and Dermoid in Mother  Open this link in a new window
      

Courtesy of  Robert R. Edelman

 
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Further Reading:
  News & More:
Motion Compensation in MR Imaging
   by ccn.ucla.edu    
Turbo-FLASH Based Arterial Spin Labeled Perfusion MRI at 7 T
Thursday, 20 June 2013   by www.plosone.org    
Usefulness of MR Imaging for Diseases of the Small Intestine: Comparison with CT
2000   by www.ncbi.nlm.nih.gov    
Searchterm 'Susceptibility Artifact' was also found in the following services: 
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Ferromagnetism
 
Ferromagnetism is a phenomenon by which a material can exhibit a spontaneous magnetization: a net magnetic moment in the absence of an external magnetic field. More recently: a material is ferromagnetic, only if all of its magnetic ions add a positive contribution to the net magnetization (for differentiation to ferrimagnetic and antiferromagnetic materials). If some of the magnetic ions subtract from the net magnetization (if they are partially anti-aligned), then the material is ferrimagnetic. If the ions anti-align completely so as to have zero net magnetization, despite the magnetic ordering, then it is an antiferromagnet. All of these alignment effects only occur at temperatures below a certain critical temperature, called the Curie temperature (for ferromagnets and ferrimagnets) or the Néel temperature (for antiferromagnets). Typical ferromagnetic materials are iron, cobalt, and nickel.
In MRI ferromagnetic objects, even very small ones, as implants or incorporations distort the homogeneity of the main magnetic field and cause susceptibility artifacts.
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• View the DATABASE results for 'Ferromagnetism' (7).Open this link in a new window

 
Further Reading:
  Basics:
Magnet basics
   by my.execpc.com    
Ferromagnetism
   by en.wikipedia.org    
Superconducting Magnets
   by hyperphysics.phy-astr.gsu.edu    
  News & More:
Physicists observe an exotic 'multiferroic' state in an atomically thin material
Wednesday, 23 February 2022   by www.sciencedaily.com    
MRI Resources 
Directories - Equipment - Cardiovascular Imaging - Movies - Examinations - MRI Technician and Technologist Schools
 
Field StrengthForum -
related threads
 
In every MR examination, a large static magnetic field is applied. Field strengths for clinical equipment can vary between 0.2 and 3 T; experimental imaging units have a field strength of up to 11 T, depending on the MRI equipment used. In MRS, field strengths up to 12 T are currently used. The field strength of the magnet will influence the quality of the MR image regarding chemical shift artifacts, the signal to noise ratio (SNR), motion sensitivity and susceptibility artifacts.

See also the related poll result: 'In 2010 your scanner will probably work with a field strength of'
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• View the NEWS results for 'Field Strength' (2).Open this link in a new window.
 
Further Reading:
  Basics:
What affects the strength of a magnet?
   by my.execpc.com    
Magnetic Field of the Strongest Magnet
2003   by hypertextbook.com    
  News & More:
Impact of Magnetic Field Inhomogeneity on the Quality of Magnetic Resonance Images and Compensation Techniques: A Review
Saturday, 1 October 2022   by www.dovepress.com    
Low Power MRI Helps Image Lungs, Brings Costs Down
Thursday, 10 October 2019   by www.medgadget.com    
Opportunities in Interventional and Diagnostic Imaging by Using High-performance Low-Field-Strength MRI
Tuesday, 1 October 2019   by pubs.rsna.org    
Low-field MRI: An MR physics perspective
Sunday, 13 January 2019   by onlinelibrary.wiley.com    
Ultra-high-field MRI allows for earlier diagnosis of multiple sclerosis
Friday, 4 May 2007   by www.eurekalert.org    
Low-intensity MRI takes first scan of a human brain
Wednesday, 14 November 2007   by technology.newscientist.com    
MRI Resources 
MRCP - Brain MRI - Anatomy - MRI Physics - Jobs - Blood Flow Imaging
 
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