1
Q
Echo Time (TE) =
Repetition Time (TR) =
A
Echo Time (TE) = Time between excitation and signal reception
Repetition Time (TR) = Time between subsequent excitations
2
Q
Cartesian Sampling Problem
A
Immediately after excitation, we are exactly in the center of k-space.
Prior to each signal acquisition
we have to reach the appropriate starting point of each line
We move in two steps: horizontally and vertically
We need to reverse the readout gradient.
3
Q
Basic Properties of GRE
A
Acquisition with short TR possible.
GRE sequences approach a non-zero steady state.
Signal decays with T2*.
Applications:
Rapid and 3D high-resolution imaging
Quantitative imaging
