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Comparison of SGRE and SSFP Cardiac MRI scans

Comparison of SGRE and SSFP Cardiac MRI scans. by Jonathan McFadden ELEC 7970 – Spring 2012 Advisor : Dr. Denning. Techniques. SGRE : Spoiled Gradient Echo Does not reuse Transverse Magnetization from previous TR-Intervals SSPP : Steady State Free Precession Two Types

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Comparison of SGRE and SSFP Cardiac MRI scans

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  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.

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