a. True. If the repetition time (TR) is shorter than the T₂ of the tissue, residual transverse magnetization remains at the time of the next radio frequency (RF) excitation pulse. Spoiling eliminates this residual transverse magnetization and the image weighting becomes more T₁-like with increasing flip angle. 

b. True. RF spoiling is the most common method for destroying transverse magnetization. Spoiling using various gradient ‘killer’ pulse schemes has been tried, but is not as effective. Examples of RF-spoiled sequences are SPGR (spoiled gradient recalled), FLASH (fast low-angle shot) and T₁-FFE (fast field echo). 

c. True. These sequences preserve residual magnetization (steady state) by using a short TR and rewinding the phase-encoding gradient after the echo has been acquired so that there is no residual phase shift dependent on the phase-encoding step. The resulting signal is proportional to the ratio of T₂/T₁; therefore, water is hyperintense on these sequences, making them perfectly suited to these types of imaging. Other uses include 3D and breath-hold imaging. Examples of such sequences are GRE, FISP (fast imaging with steady-state precession) and FFE. 

d. False. Motion and flow destroy the steady state on which these sequences depend. 

e. True. Due to the very short TRs, in order not to saturate the transverse magnetization, only very small excitation flip angles are used, resulting in poor T₁ contrast. This can be overcome by applying preparation pulses, such as a 180° inversion prior to acquisition, which improves the T₁ contrast between tissues.