=====Pulse sequence=====
[[Magnetic resonance imaging]] (MRI) is able to achieve its striking ability to image tissues in various ways by manipulating the various electromagnetic fields it is able to generate. The pattern in these fields are changed is known as a pulse sequence. There are many (hundreds - see MRI pulse sequence abbreviations) of various pulse sequences each changing the appearances of tissue. 

These can be grouped as follows:

[[Spin-echo sequence]]s

inversion recovery sequences

gradient echo sequences

diffusion weighted sequences

saturation recovery sequences

echo-planar pulse sequences

spiral pulse sequences