1
Pulse Sequences
The advanced-level MRI examination will contain 12 questions on pulse sequences. The topics covered are
- Spin echo
– Conventional spin echo
– Fast spin echo
- Inversion recovery
- Gradient recalled echo
– Conventional gradient echo
– Fast gradient echo
Q1 An inversion recovery spin echo sequence begins with a:
| (a) | 90° RF pulse |  |
| (b) | 180° RF pulse |  |
| (c) | 45° RF pulse |  |
| (d) | a or b |  |
Q2 To produce the echo, a gradient echo pulse sequence uses:
| (a) | A gradient magnetic field only |  |
| (b) | An RF pulse only |  |
| (c) | A combination of a and b |  |
| (d) | A switching device |  |
| (e) | A combination of any two RF pulses |  |
Q3 The 180° pulse that follows the initial 90° pulse in a spin echo sequence will cause the NMR signal to reappear while correcting for:
| (a) | Slight magnetic field inhomogeneities |  |
| (b) | Chemical shift |  |
| (c) | Slight magnetic susceptibility effects |  |
| (d) | All of the above |  |
Q4 If the TR of a gradient echo pulse sequence is considerably less than the T2 (and T2*), the condition that will exist is known as:
| (a) | Steady state |  |
| (b) | Spin dephasing |  |
| (c) | Spin rephasing |
