Steady State Free Precession MRA

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-SSFP Magnetic Resonance Angiography

1. Steady State Free Precession Based MRA Rahman Ud Din Lecturer Medical Imaging NWIHS

2. Learning Outcomes Residual Magnetization What is a SSFP? How SSFP can be produced? SSFP Based MRA Limitations

3. Residual Magnetization

4. SSFP-Based MRA Steady - state free precession ( SSFP ) is a type of gradient echo MRI pulse sequence in which a steady , residual transverse magnetization ( M xy ) is maintained between successive cycles The sequence is noted for its superiority in dynamic/cine assessment of cardiac function

5. The transverse magnetization dies out in the middle between the RF pulses. If the pulses are applied sufficiently rapidly (i.e. TR<<T2), however, the tails of the "FIDs" and "Echoes" will merge, so that a continuous signal of varying amplitude is produced. This is known as a steady-state free precession (SSFP) . 

6. SSFP-Based MRA… Veins, other fluid and fat are also bright on this seq Subtraction is required Arterial spin labeling (ASL) or inversion recovery pulses are used e.g. Time SLIP, NATIVE TrueFISP , IFIR Used in renal and abdominal arteries

7. SSFP-Based MRA Balanced SSFP seq ; are GRE steady state seq ; High SNR and motion insensitivity due to balanced gradients in all three directions They are als o called TruFISP (s), FIESTA(GE) and balanced-TFE (Philips) Giving the blood very high signal without dependence on inflow

8. Limitations ; Relatively complex imaging and S usceptibility to field inhomogenities

9. SSFP-Based Cine Imaging

10. SSFP-Based MRA