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 'Gradient Echo' 
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Result : Searchterm 'Gradient Echo' found in 20 terms [] and 114 definitions []
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Searchterm 'Gradient Echo' was also found in the following services: 
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Balanced SARGEInfoSheet: - Sequences - 
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(BASG) The spoiled steady state acquisition rewinded gradient echo sequence with balanced waveform.

See Steady State Free Precession, Gradient Echo Sequence and Balanced Sequence.
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Blood Oxygenation Level Dependent ContrastInfoSheet: - Sequences - 
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(BOLD) In MRI the changes in blood oxygenation level are visible. Oxyhaemoglobin (the principal haemoglobin in arterial blood) has no substantial magnetic properties, but deoxyhaemoglobin (present in the draining veins after the oxygen has been unloaded in the tissues) is strongly paramagnetic. It can thus serve as an intrinsic paramagnetic contrast agent in appropriately performed brain MRI. The concentration and relaxation properties of deoxyhaemoglobin make it a susceptibility , e.g. T2 relaxation effective contrast agent with little effect on T1 relaxation.
During activation of the brain, the oxygen consumption of the local tissue increase by approximately 5% with that the oxygen tension will decrease. As a consequence, after a short period of time vasodilatation occurs, resulting in a local increase of blood volume and flow by 20 - 40%. The incommensurate change in local blood flow and oxygen extraction increases the local oxygen level.
By using T2 weighted gradient echo EPI sequences, which are highly susceptibility sensitive and fast enough to capture the three-dimensional nature of activated brain areas will show an increase in signal intensity as oxyhaemoglobin is diamagnetic and deoxyhaemoglobin is paramagnetic. Other MR pulse sequences, such as spoiled gradient echo pulse sequences are also used.
As the effects are subtle and of the order of 2% in 1.5 T MR imaging, sophisticated methodology, paradigms and data analysis techniques have to be used to consistently demonstrate the effect.
As the BOLD effect is due to the deoxygenated blood in the draining veins, the spatial localization of the region where there is increased blood flow resulting in decreased oxygen extraction is not as precisely defined as the morphological features in MRI. Rather there is a physiological blurring, and is estimated that the linear dimensions of the physiological spatial resolution of the BOLD phenomenon are around 3 mm at best.
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• View the DATABASE results for 'Blood Oxygenation Level Dependent Contrast' (6).Open this link in a new window

 
Further Reading:
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IMAGE CONTRAST IN MRI(.pdf)
   by www.assaftal.com    
Vascular Filters of Functional MRI: Spatial Localization Using BOLD and CBV Contrast
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A mechanistic computational framework to investigate the hemodynamic fingerprint of the blood oxygenation level-dependent signal
Tuesday, 29 August 2023   by analyticalsciencejournals.onlinelibrary.wiley.com    
The utility of texture analysis of kidney MRI for evaluating renal dysfunction with multiclass classification model
Tuesday, 30 August 2022   by www.nature.com    
MRI Technique Used to Identify Future Risk of Binge Drinking
Monday, 6 January 2020   by www.diagnosticimaging.com    
Gold Acupuncture Needle MRI Pain Discovery
Friday, 3 January 2014   by www.healthcmi.com    
MRI method for measuring MS progression validated
Thursday, 19 December 2013   by www.eurekalert.org    
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Contrast Enhanced FASTInfoSheet: - Sequences - 
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(CE-FAST) In this technique, the MR signal is sampled immediately prior to each RF pulse. Because the signal is formed by a true spin echo, its contrast is predominantly T2-, rather than T2*-based and is less sensitive to artifacts and signal losses related to field non-uniformity and susceptibility variation. While the signal to noise ratio is limited, the CE-FAST method has the advantage of good contrast.

See Contrast Enhanced Gradient Echo Sequence and Gradient Echo Sequence.
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• View the DATABASE results for 'Contrast Enhanced FAST' (5).Open this link in a new window

Searchterm 'Gradient Echo' was also found in the following services: 
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Contrast Enhanced Fast Field Echo with T1 WeightingInfoSheet: - Sequences - 
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• View the DATABASE results for 'Contrast Enhanced Fast Field Echo with T1 Weighting' (2).Open this link in a new window

MRI Resources 
Mobile MRI - Equipment - Cochlear Implant - Spectroscopy pool - Coils - MRI Training Courses
 
Dual Fast Field EchoInfoSheet: - Sequences - 
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(Dual/FFE) A FFE technique with simultaneously acquired in and out of phase gradient echoes.

See Dual Echo Fast Gradient Echo.
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Further Reading:
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Adrenal Metastases
Friday, 15 March 2002   by www.emedicine.com    
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Claustrophobia - Quality Advice - Sequences - Pediatric and Fetal MRI - Manufacturers - Used and Refurbished MRI Equipment
 
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