Gradient echo sequences T1 T2 PD

  1. What is the specific flip angles used in gradient echo sequences
    they can be variable starting 0-180 degree
  2. what are the typical values in gradient echo with a long tr and short tr
    • long: 100ms+ 
    • short tr: less than 50 ms
  3. what are the values of a low flip angle range
    between 5-20degress
  4. what are the large flip angles used in gradient sequences
    70+ degree
  5. in order to obtain a t1 weighted image in gradient sequence yo need what te? tr? flip?
    • short tr 
    • short te 
    • and large flip angle
  6. How do you produce a t2 weighted image
    • Long tr and te 
    • small flip angle
  7. How do you produce a pd image
    • long tr short te 
    • small flip angle
  8. Using a long TE enhances T2 and T2* contrast.
    t or F
    True because Long TEs always give the spins more time to dephase before the echo is read, therefore increasing T2 contrast. This is true in spin echo and gradient echo sequences.
  9. Combining a low flip and long TR results in saturation.
    true or false
    False. This combination results in the vectors being flipped through a small angle while giving them a long time to recover using a long TR. Hence the vectors never exist beyond the transverse plane in saturation.
Card Set
Gradient echo sequences T1 T2 PD