2016_Imaging for Physicists

Steady State Sequences

• Rewinding (SS-FID) – Maintains coherent transverse magnetisation – FISP, GRASS rewind phase encoding only – ‘True’ FISP or bFFE rewind all 3 gradient directions Have to additionally phase cycle RF (ROAST) • Time Reversed sequences (SS-Echo) – PSIF – Use (Hahn) echo -essentially T 2 -weighted

FAST FISP GRASS bFFE/bSSFP FIESTA

CE-FAST PSIF SSFP

Signals depend on: flip angle, T 1 /T 2