(LASE) See Gradient Echo Sequence and Spin Echo Sequence.

(MSE) A spin echo technique with a flip angle over 90°.

See Spin Echo Sequence and Fast Spin Echo.

Pulse sequences, designed to be insensitive to flow, e.g. at every even echo, a spin echo sequence is not flow sensitive. Velocity compensation is achieved by using gradients, which are either symmetrical around a 180° pulse and switched on twice as is the case for motion compensated spin echo pulse sequences, or two antisymmetrical gradient lobes without 180° pulse, which is the way to produce a velocity compensated gradient echo pulse sequence.
The signal of the second echo (and all other even echoes) is independent of the velocity of the object. Thus, velocity-based motion effects stemming from the entire voxel or from spins within a voxel (intravoxel incoherent motion) are suppressed with such pulse sequences.
If higher order motion is relevant, as it may be in turbulent jets across valves, acceleration and jerk effects can also be compensated for by the use of appropriate combinations of gradient- and radio frequency pulses.
With the increasingly stronger gradients, echo times in MR systems can be shortened to the point at which effects other than velocity effects hardly ever become relevant.

Multi echo imaging sequences use a series of echoes acquired as a train following after a single excitation pulse. Multiple symmetrical or asymmetrical echoes can be acquired, typically T2 weighted. In spin echo imaging, each echo is formed by a 180° pulse, but also a FSE (TSE, RARE) or EPI sequence can be used. As a difference to a normal fast spin echo sequence, in multi echo imaging, separate images are produced from each echo of the train with different T2 weightings. The signal height reduces with transverse relaxation. This drop in signal can be used to calculate a pure T2 image.

See also Fast Spin Echo.

(PROPELLER) The PROPELLER MRI technique reduces the sensitivity to various sources of image artifacts (e.g., motion artifact, field inhomogeneity artifact, eddy current artifact). PROPELLER can be used with gradient echo and turbo spin echo sequences in a wide range of applications to improve the image quality, for example cardiac MRI, brain MRI, and pediatric examinations.