pulse sequence
A programmed timing pattern of RF pulses and gradient switching that acquires MRI images. T1, T2, FLAIR, DWI, EPI, gradient-echo, MR angiography, MR spectroscopy, and many specialty sequences are all defined by their pulse-sequence parameters (TR, TE, TI, flip angle, gradient timing).
Why it matters to buyers: Clinical application depends on available sequences. Licensed application packages gate what the scanner can do. A premium magnet without advanced sequence licensing performs at the value-tier capability.
Why it matters to engineers: Sequence database is versioned with host software (syngo MR, ISD on Philips, GE host software). Software upgrades enable new sequences; cross-vendor sequence development happens through proprietary tooling specific to each platform.