(PRESTO) PRESTO is a 3 dimensional ultrafast gradient echo sequence that combines the whole brain coverage with T2* weighted imaging. PRESTO is useful for BOLD and perfusion imaging studies. In combination with parallel imaging techniques, PRESTO provides higher temporal resolution and more coverage compared to traditional multi slice imaging. In addition, the sensitivity to susceptibility artifacts and flow phenomena is reduced, compared with EPI techniques, enabling MRI scans throughout the brain including the skull base.

See also T2 Star.

(RAM-FAST) A fast gradient echo pulse sequence using a magnetization preparation pulse.

See Ultrafast Gradient Echo Sequence.

(RE MRI) There are several approaches to speeding up the MRI data acquisition process by repeating the excitation by RF pulses in times short compared to T1, typically using small flip angles and gradient echo refocusing. When TR is also on the order of or shorter than T2, the repeated RF pulses will tend to refocus transverse magnetization remaining from prior excitations, setting up a condition of steady state free precession, and a dependence of signal strength (and image contrast) on both T1 and T2.
This can be modified in various ways, particularly:
1) to spoil the tendency to build up a steady state by reducing coherence between excitations, e.g. by variation of the phase or timing of consecutive RF pulses or of the strength of spoiler gradient pulses, thus increasing the relative dependence of signal strength on T1 or
2) acquire the signal when it is refocusing immediately prior to the next RF pulse, thus increasing the relative dependence of signal strength on T2.

See also Ultrafast Gradient Echo Sequence.

(RS) A very fast gradient echo sequence.

See Ultrafast Gradient Echo Sequence.

(SMASH) A very fast gradient echo sequence.

See Ultrafast Gradient Echo Sequence.