premise: Fast low angle shot magnetic resonance imaging (FLASH MRI) is a particular sequence of magnetic resonance imaging. It is a gradient echo sequence which combines a low-flip angle radio-frequency excitation of the nuclear magnetic resonance signal (recorded as a spatially encoded gradient echo) with a rapid repetition time. It is the generic form of steady-state free precession imaging.
hypothesis: FLASH comes from the light emitted with an MRI.
reason: I used a key word but in a different context.