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Result : Searchterm 'T2' found in 8 terms [] and 150 definitions []
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Searchterm 'T2' was also found in the following services: 
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News  (28)  Resources  (5)  Forum  (66)  
 
Spin EchoForum -
related threads
 
(SE) The Reappearance of the MR signal after the FID has apparently died away, as a result of the effective reversal (rephasing) of the dephasing spins by techniques such as specific RF pulse sequences or pairs of field gradient pulses, applied in time shorter than or on the order of T2. Proper selection of the TE time of the pulse sequence can help to control the amount of T1 or T2 contrast present in the image. Pulse sequences of the spin echo type, usually employs a 90° pulse, followed by one or more 180° pulses to eliminate field inhomogeneity and chemical shift effects at the echo. Caused by this 180° refocusing pulse, spin echo or fast spin echo (FSE, TSE) sequences are more robust against e.g. susceptibility artifacts than sequences of the gradient echo type.
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• Related Searches:
    • Spin Echo Sequence
    • Relaxivity
    • Resonance Frequency
    • Echo Time
    • Radio Frequency
 
Further Reading:
  Basics:
Spin echoes, CPMG and T2 relaxation - Introductory NMR & MRI from Magritek
2013   by www.azom.com    
  News & More:
EVALUATION OF HUMAN STROKE BY MR IMAGING
2000
MRI Resources 
Education pool - Bioinformatics - Implant and Prosthesis pool - Image Quality - Sequences - Spectroscopy
 
Spin Echo Multi SliceInfoSheet: - Sequences - 
Intro, 
Overview, 
Types of, 
etc.MRI Resource Directory:
 - Sequences -
 
(SEMS) This pulse sequence is composed of a 90° RF pulse followed by a 180° refocusing pulse. Both RF pulses are applied in the presence of a slice select gradient.
By choosing of different TR and TE, depending on the T1 and T2 values of the tissues, proton density, T1 weighted and T2 weighted images can be acquired.
The inversion recovery option enlarge the RF pulses with a 180° inverting pulse, applied a TI time before the beginning of the pulse sequence in order to manipulate image contrast.
See also Spin Echo Sequence.
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Further Reading:
  Basics:
Fast Spin Echo(.pdf)
Tuesday, 24 January 2006   by www.81bones.net    
MRI Resources 
Cardiovascular Imaging - Case Studies - Contrast Agents - Safety pool - Nerve Stimulator - MRA
 
Steady State Free Precession SequenceInfoSheet: - Sequences - 
Intro, 
Overview, 
Types of, 
etc.MRI Resource Directory:
 - Sequences -
 
(SFP or SSFP) Steady state free precession is any field or gradient echo sequence where the TR is shorter than the T1 and T2 times of the tissue.
The flip angle and the TR maintain the steady state. The flip angle should be 60-90° if the TR is 100 ms, if the TR is less than 100 ms, than the choice of the flip angle for steady state is 45-60°. The T1 weighting is controlled by TR and flip, the T2 weighting increases with the TE. Common TR is between 20 - 50 msec.
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Further Reading:
  News & More:
Generic Eddy Current Compensation for Rapid Magnetic Resonance Imaging(.pdf)
   by www.switt.ch    
Cutting Edge Imaging of THE Spine
February 2007   by www.pubmedcentral.nih.gov    
Searchterm 'T2' was also found in the following services: 
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News  (28)  Resources  (5)  Forum  (66)  
 
Superparamagnetic Iron OxideInfoSheet: - Contrast Agents - 
Intro, Overview, 
Characteristics, 
Types of, 
etc.
 
(SPIO) Relatively new types of MRI contrast agents are superparamagnetic iron oxide-based colloids (median diameter greater than 50nm). These compounds consist of nonstoichiometric microcrystalline magnetite cores, which are coated with dextrans (in ferumoxide) or siloxanes (in ferumoxsil). After injection they accumulate in the reticuloendothelial system (RES) of the liver (Kupffer cells) and the spleen. At low doses circulating iron decreases the T1 time of blood, at higher doses predominates the T2* effect.
SPIO agents are much more effective in MR relaxation than paramagnetic agents. Since hepatic tumors either do not contain RES cells or their activity is reduced, the contrast between liver and lesion is improved. Superparamagnetic iron oxides cause noticeable shorter T2 relaxation times with signal loss in the targeted tissue (e.g., liver and spleen) with all standard pulse sequences. Magnetite, a mixture of FeO and Fe2O3, is one of the used iron oxides. FeO can be replaced by Fe3O4.
Use of these colloids as tissue specific contrast agents is now a well-established area of pharmaceutical development. Feridex®, Endorem™, GastroMARK®, Lumirem®, Sinerem®, Resovist® and more patents pending tell us that the last word in this area is not said.
Some remarkable points using SPIO:
A minimum delay of about 10 min. between injection (or infusion) and MR imaging, extends the examination time.
Cross-section flow void in narrow blood vessels may impede the differentiation from small liver lesions.
Aortic pulsation artifacts become more pronounced.


See also Superparamagnetism, Superparamagnetic Contrast Agents and Classifications, Characteristics, etc..
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• View the DATABASE results for 'Superparamagnetic Iron Oxide' (32).Open this link in a new window


• View the NEWS results for 'Superparamagnetic Iron Oxide' (3).Open this link in a new window.
 
Further Reading:
  Basics:
IMAGE CONTRAST IN MRI(.pdf)
   by www.assaftal.com    
  News & More:
How to stop using gadolinium chelates for magnetic resonance imaging: clinical-translational experiences with ferumoxytol
Saturday, 5 February 2022   by www.ncbi.nlm.nih.gov    
Polysaccharide-Core Contrast Agent as Gadolinium Alternative for Vascular MR
Monday, 8 March 2021   by www.diagnosticimaging.com    
Poly (dopamine) coated superparamagnetic iron oxide nanocluster for noninvasive labeling, tracking, and targeted delivery of adipose tissue-derived stem cells
Tuesday, 5 January 2016   by www.nature.com    
Longitudinal MRI contrast enhanced monitoring of early tumour development with manganese chloride (MnCl2) and superparamagnetic iron oxide nanoparticles (SPIOs) in a CT1258 based in vivo model of prostate cancer
Wednesday, 11 July 2012   by www.biomedcentral.com    
MRI Resources 
MRI Technician and Technologist Schools - Mobile MRI Rental - Veterinary MRI - Movies - Liver Imaging - Safety Training
 
Transverse Magnetization
 
The xy component of the net magnetization vector at right angles to the main magnetic field. The precession of the transverse magnetization at the Larmor frequency is responsible for the detectable MRI signal. In the absence of externally applied RF energy, the transverse magnetization will decay to zero with a characteristic time constant of T2, or more strictly T2*.
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• View the DATABASE results for 'Transverse Magnetization' (43).Open this link in a new window

 
Further Reading:
  Basics:
Measuring T1 and T2 Relaxation - Introductory NMR & MRI from Magritek
   by www.azom.com    
MRI Resources 
Image Quality - Used and Refurbished MRI Equipment - Mobile MRI - MRI Accidents - Bioinformatics - Service and Support
 
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