Howtosignalprocessing
- Which gradient is applied during the production of an echo in a gradient echo sequence?
- Why scan time of gradient echo sequence is shorter spin echo sequences?
- What is the result of the gradients being turned on and off very rapidly over a period of time?
- What is gradient echo sequence in MRI?
Which gradient is applied during the production of an echo in a gradient echo sequence?
As there is no 180° RF pulse, a bipolar readout gradient (which is the same as the frequency-encoding gradient) is required to create an echo. The gradient echo formation results from applying a dephasing gradient before the frequency-encoding or readout gradient.
Why scan time of gradient echo sequence is shorter spin echo sequences?
First, because only one RF-pulse is applied, the echo can be recorded much more quickly in a GRE sequence. As a result, echo time (TE) is generally shorter for GRE sequences than for SE sequences.
What is the result of the gradients being turned on and off very rapidly over a period of time?
The gradients are turned on and off very quickly in this process causing them to vibrate causing the majority of the noise associated with the MRI environment.
What is gradient echo sequence in MRI?
Gradient echo sequences (GRE) are an alternative technique to spin-echo sequences, differing from it in two principal points: utilization of gradient fields to generate transverse magnetization. flip angles of less than 90°
