James D. Christensen, Ph.D. IU School of Medicine

1. BME 595 - Medical Imaging ApplicationsPart 2: INTRODUCTION TO MRILecture 3 Multi-Dimensional ImagingFeb. 28, 2005 James D. Christensen, Ph.D. IU School of Medicine Department of RadiologyResearch II building, E002C jadchris@iupui.edu317-274-3815

2. References Online resources for introductory review of MRI physics: • Robert Cox’s book chapters online • http://afni.nimh.nih.gov/afni/edu/ • See “Background Information on MRI” section • Mark Cohen’s intro Basic MR Physics slides • http://porkpie.loni.ucla.edu/BMD_HTML/SharedCode/MiscShared.html • Douglas Noll’s Primer on MRI and Functional MRI • http://www.bme.umich.edu/~dnoll/primer2.pdf • Joseph Hornak’s Web Tutorial, The Basics of MRI • http://www.cis.rit.edu/htbooks/mri/mri-main.htm Book covering Multi-Dimensional MRI: • E. Mark Haacke, et al. Magnetic Resonance Imaging: Physical Principles and Sequence Design, 1999.

3. Phase-Encoding

4. 2D Gradient-Echo Pulse Sequence (a)

5. 2D Gradient-Echo Pulse Sequence (b)

6. 2D Gradient-Echo K-Space

7. Multi-Slice 2D Pulse Sequence

8. Multi-Slice 2D Slice Excitation

9. 2D Echo-Planar Imaging (EPI) Pulse Sequence K-Space Trajectory

10. 3D Gradient-Echo Pulse Sequence Phase Spoiling: (RF or gradients) causes Incoherence in transverse magnetization

11. Fast-Imaging(Steady-State Incoherent pulse sequence) For a train of RF pulses repeated every TR seconds The steady-state equilibrium magnetization is where The transverse magnetization following the nth RF pulse is The Steady-State Incoherent signal intensity is proportional to M

12. Flip Angle (θ), TR & T1 in Fast Imaging where Steady-State Incoherent (SSI) signal intensity:

13. Flip Angle (θ), TR & T1 in Fast Imaging where

14. Steady-State Coherence Pulse Sequence

15. Steady-State Coherence Pulse Sequence

16. Chemical-Shift Imaging (CSI)

17. Chemical-Shift Imaging (CSI)

18. Chemical-Shift Imaging (CSI)

19. Chemical-Shift Imaging (CSI)

20. Homework Problem 1