T2 weighting

body of water during golden hour
  • Manipulating TR and TE helps us to weight the contrast of the image to a certain parameter while diminishing the impact of other parameters
  • In T2 weighting, the T2 relaxation time of tissues is accentuated and the T1 effects decreased
  • How we achieve this is by using a long TE – which allows both fat and water to fully decay. At the same time, in order to diminish the T1 effects, we use a long TR
  • It’s classically described to demonstrate pathology, as water content tends to be more
Why does water appear bright in T2 weighted imaging?
  • Water since it has a long decay time, retains much of its transverse magnetization during the long TE and as a result has a bright signal
Why is fat dark in T2 weighted imaging?
  • Fat decays fast and loses much of its transverse magnetization during the long TE and as a result appears dark
What values do you enter to get a T2 weighted image?
  • TR: 2000 ms or more
  • TE: 70 ms or more
What are the common sequences used to produce T2 weighted imaging?
  • Spin echo
  • Turbo spin echo
  • STIR
  • FLAIR