Magnetic Resonance - Technology Information Portal Welcome to MRI Technology••
Info
  Sheets


Out-
      side
 



 
 'Steady State Free Precession' 
SEARCH FOR    
 
  2 3 5 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Result : Searchterm 'Steady State Free Precession' found in 3 terms [] and 17 definitions []
1 - 5 (of 20)     next
Result Pages : [1]  [2 3 4]
Searchterm 'Steady State Free Precession' was also found in the following service: 
spacer
News  (3)  
 
Steady State Free PrecessionInfoSheet: - Sequences - 
Intro, 
Overview, 
Types of, 
etc.MRI Resource Directory:
 - Sequences -
 
(SFP or SSFP) Steady state free precession is any field or gradient echo sequence in which a non-zero steady state develops for both components of magnetization (transverse and longitudinal) and also a condition where the TR is shorter than the T1 and T2 times of the tissue. If the RF pulses are close enough together, the MR signal will never completely decay, implying that the spins in the transverse plane never completely dephase. 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, then the flip angle for steady state should be 45-60°.
Steady state free precession is also a method of MR excitation in which strings of RF pulses are applied rapidly and repeatedly with interpulse intervals short compared to both T1 and T2. Alternating the phases of the RF pulses by 180° can be useful. The signal reforms as an echo immediately before each RF pulse;; immediately after the RF pulse there is additional signal from the FID produced by the pulse.
The strength of the FID will depend on the time between pulses (TR), the tissue and the flip angle of the pulse; the strength of the echo will additionally depend on the T2 of the tissue. With the use of appropriate dephasing gradients, the signal can be observed as a frequency-encoded gradient echo either shortly before the RF pulse or after it; the signal immediately before the RF pulse will be more highly T2 weighted. The signal immediately after the RF pulse (in a rapid series of RF pulses) will depend on T2 as well as T1, unless measures are taken to destroy signal refocusing and prevent the development of steady state free precession.
To avoid setting up a state of SSFP when using rapidly repeated excitation RF pulses, it may be necessary to spoil the phase coherence between excitations, e.g. with varying phase shifts or timing of the exciting RF pulses or varying spoiler gradient pulses between the excitations.
Steady state free precession imaging methods are quite sensitive to the resonant frequency of the material. Fluctuating equilibrium MR (see also FIESTA and DRIVE)and linear combination SSFP actually use this sensitivity for fat suppression. Fat saturated SSFP (FS-SSFP) use a more complex fat suppression scheme than FEMR or LCSSFP, but has a 40% lower scan time.
A new family of steady state free precession sequences use a balanced gradient, a gradient waveform, which will act on any stationary spin on resonance between 2 consecutive RF pulses and return it to the same phase it had before the gradients were applied.
This sequences include, e.g. Balanced Fast Field Echo - bFFE, Balanced Turbo Field Echo - bTFE, Fast Imaging with Steady Precession - TrueFISP and Balanced SARGE - BASG. See also FIESTA.
spacer
 
• Share the entry 'Steady State Free Precession':  Facebook  Twitter  LinkedIn  
 
• Related Searches:
    • Gradient Echo Sequence
    • Longitudinal Magnetization
    • Transverse Magnetization
    • Spoiled Gradient Echo Sequence
    • Larmor Frequency
 
Further Reading:
  News & More:
Comparison of New Methods for Magnetic Resonance Imaging of Articular Cartilage(.pdf)
2002
MRI Resources 
Manufacturers - Shoulder MRI - Safety pool - MRI Centers - Hospitals - Mobile MRI
 
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.
spacer
 
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    
MRI Resources 
Bioinformatics - Education - Pacemaker - Diffusion Weighted Imaging - Safety Products - Libraries
 
Double Mode Steady State Free PrecessionInfoSheet: - Sequences - 
Intro, 
Overview, 
Types of, 
etc.MRI Resource Directory:
 - Sequences -
 
(DMSSFP) See Steady State Free Precession.
spacer
Searchterm 'Steady State Free Precession' was also found in the following service: 
spacer
News  (3)  
 
Fourier Acquired Steady StateInfoSheet: - Sequences - 
Intro, 
Overview, 
Types of, 
etc.
 
(FAST) A gradient echo sequence with steady state free precession.
See Gradient Echo Sequence and Steady State Free Precession.
spacer

• View the DATABASE results for 'Fourier Acquired Steady State' (5).Open this link in a new window

MRI Resources 
Corporations - Cardiovascular Imaging - Online Books - Jobs - Societies - Musculoskeletal and Joint MRI
 
Balanced Fast Field EchoInfoSheet: - Sequences - 
Intro, 
Overview, 
Types of, 
etc.MRI Resource Directory:
 - Sequences -
 
(bFFE) A FFE sequence using a balanced gradient waveform. A balanced sequence starts out with a RF pulse of 90° or less and the spins in the steady state. Before the next TR in the slice phase and frequency encoding, gradients are balanced so their net value is zero. Now the spins are prepared to accept the next RF pulse, and their corresponding signal can become part of the new transverse magnetization. Since the balanced gradients maintain the transverse and longitudinal magnetization, the result is, that both T1 and T2 contrast are represented in the image. This pulse sequence produces images with increased signal from fluid, along with retaining T1 weighted tissue contrast. Because this form of sequence is extremely dependent on field homogeneity, it is essential to run a shimming prior the acquisition. A fully balanced (refocused) sequence would yield higher signal, especially for tissues with long T2 relaxation times.
See Steady State Free Precession and Gradient Echo Sequence.

 
Images, Movies, Sliders:
 Cardiac Infarct Short Axis Cine bFFE 1  Open this link in a new window
    
 
spacer

• View the DATABASE results for 'Balanced Fast Field Echo' (3).Open this link in a new window

 
Further Reading:
  News & More:
T1rho-prepared balanced gradient echo for rapid 3D T1rho MRI
Monday, 1 September 2008   by www.ncbi.nlm.nih.gov    
Utility of the FIESTA Pulse Sequence in Body Oncologic Imaging: Review
June 2009   by www.ajronline.org    
MRI Resources 
Spectroscopy - Directories - Mass Spectrometry - Universities - Contrast Enhanced MRI - PACS
 
     1 - 5 (of 20)     next
Result Pages : [1]  [2 3 4]
 Random Page
 
Share This Page
FacebookTwitterLinkedIn

MR-TIP    
Community   
User
Pass
Forgot your UserID/Password ?  



The impact of TTIP/TPP on the MRI scanner market will bring :
more variety 
better scanners 
more risk 
less regulation 
cheaper scanners 
Lost in Translation 
no change at all 

Look
      Ups





MR-TIP.com uses cookies! By browsing MR-TIP.com, you agree to our use of cookies.

Magnetic Resonance - Technology Information Portal
Member of SoftWays' Medical Imaging Group - MR-TIP • Radiology-TIP • US-TIP • The-Medical-Market
Copyright © 2003 - 2018 SoftWays. All rights reserved. [ 18 July 2018]
Terms of Use | Privacy Policy | Advertising
 [last update: 2018-03-08 05:11:00]