Comparison of SGRE and SSFP Cardiac MRI scans

1. Comparison of SGRE and SSFP Cardiac MRI scans by Jonathan McFadden ELEC 7970 – Spring 2012 Advisor : Dr. Denning

2. Techniques • SGRE : Spoiled Gradient Echo • Does not reuse Transverse Magnetization from previous TR-Intervals • SSPP : Steady State Free Precession • Two Types • Non-alternating Flip-Angle • Alternating Flip-Angle • Reuses Transverse Magnetization from previous TR-Intervals

3. Goals • General Theoretical Coverage of SGRE and both SSFPs • Simulations of each technique alone • Simulations to compare each technique to the others

4. General Theoretical Coverage • Solve for the Equilibrium Magnetization vector for SGRE • Solve for the Equilibrium Magnetization vector for SSFP with a non-alternating flip-angle • Solve for the Equilibrium Magnetization vector for SSFP with a non-alternating flip-angle

5. Simulations • Initial • Single Vector • Region of Vectors • Final • Single Vector • Four Vector (dB) • Four Vector (Tab)

6. Theoretical Results • Solved Bloch Equation • Equilibrium Conditions • Connected solution of Bloch Equation to these techniques • Solved for Equilibrium Magnetization Vectors (using Mathematica) • Mathematically proved that the SSFPs differ by and rotation of pi about the z-axis

7. Rotation About Z-axis

8. Initial Simulations • Show

9. Final Simulations 1

10. Final Simulations 2

11. Final Simulations • Show

12. Simulation Results 1 • Spoiled GRE is unaffected by magnetic field inhomogeneities over more than the TR-Interval in question. • Both SSFP techniques carry the effects of magnetic field inhomogeneities over more than the TR-Interval in question.

13. Simulation Results 2 • The contrast between tissues when using SSFP with an alternating flip-angle is stronger than the signal from SSFP with a non-alternating flip-angle. • The contrast between tissues when using SSFP with a non-alternating flip-angle is stronger than the signal from Spoiled GRE.