gradient echo

noun

: a signal that is detected in a nuclear magnetic resonance spectrometer that is analogous to a spin echo but is produced by varying the external magnetic field following application of a single radio-frequency pulse rather than by application of a series of radio-frequency pulses and that can be used to extract more information from a test sample or subject than is possible in conventional nuclear magnetic resonance spectroscopy

—usually used attributively

gradient-echo magnetic resonance imaging of the brain