About this task
Select a Flip Angle for the desired image contrast weight and SNR for a Spin Echo pulse sequence.
Step-by-step instructions
- Scan selections: 2D Mode, Spin Echo family, Spin Echo pulse.
- At the bottom of the expanded Imaging Options/PSD screen, type t1memp In the PSD Name text box.
- From the TR menu, select a TR value.
- From the Flip Angle menu, select Auto.
- The system automatically sets the Flip Angle from the TR value to provide optimal T1 image contrast.
The following graph illustrates different flip angles correlated to different TR values.
Note: that the optimum contrast with a varied flip angle is the same curve. Curves 4 and 6 illustrate that the lower the TR the higher the flip angle.
Figure 1. Flip angle and TR
Table 1. Table legend| Number | Description |
|---|
| 1 | Flip angle in degrees. |
| 2 | TR (repetition time) in ms. |
| 3 | Ernst angle to achieve highest signal for white matter. |
| 4 | Flip angle for t1memp PSD. |
| 5 | Spin Echo flip angle. |
| 6 | The optimum flip angle to achieve the best signal difference between gray and white matter. |