4. SSFP-Based MRA
ď‚— Steady-state free precession(SSFP) is a type
of gradient echo MRI pulse sequence in which
a steady, residual transverse magnetization
(Mxy) is maintained between successive cycles
ď‚— The sequence is noted for its superiority in
dynamic/cine assessment of cardiac function
5. ď‚— The transverse magnetization dies out in the
middle between the RF pulses.
ď‚— If the pulses are applied sufficiently rapidly (i.e.
TR<<T2), however,
ď‚— the tails of the "FIDs" and "Echoes" will merge,
so that a continuous signal of varying
amplitude is produced.
ď‚— This is known as a steady-state free
precession (SSFP).
6. SSFP-Based MRA…
ď‚— Veins, other fluid and fat are also bright on this
seq
ď‚— Subtraction is required
ď‚— Arterial spin labeling (ASL) or inversion
recovery pulses are used
ď‚— e.g. Time SLIP, NATIVE TrueFISP, IFIR
ď‚— Used in renal and abdominal arteries
7. SSFP-Based MRA
ď‚— Balanced SSFP seq; are GRE steady
state seq;
ď‚— High SNR and motion insensitivity due
to balanced gradients in all three
directions
ď‚— They are also called TruFISP(s),
FIESTA(GE) and balanced-TFE
(Philips)
ď‚— Giving the blood very high signal
without dependence on inflow