1. MRI, FBP and phase encoding

2. Spins

3. Precession

4. RF pulse

5. T1 and T2

6. Bloch Equations

7. Receiver

8. T1 and T2

9. Effect of tissue T1 and T2 CONSTANTS T2 Constants at 1.5 T Controlled by TE T1 Constants at 1.5 T Controlled by TR 85Fat 45860Muscle 90780White matter 100920Gray matter 14003000CSF

10. Slice selection

12. FBP

13. Filtered Back Projection

16. Filtered backprojection Filter the measured projection data at different projection angles with a special function. Backproject the filtered projection data to form the reconstructed image. Filtering can be implemented in 2 ways, in the spatial domain, the filter operation is equivalent to to convolving the measured projection data using a special convolving function h(t) More efficient multiplication will be in the spatial frequency domain. FFT the measured projection data into the frequency domain: p(,  )=FT {p(t,  ) Multiply the the fourier transform projections with the special function. Inverse Fourier transform the product p ’ (,  ).

17. Phase Encoding Gradient FrequencyPhaseSlice Slice Plane Y or XX or YZXY Z or XX or ZYXZ Z or YY or ZXYZ

18. Phase encoding

19. K space

20. K Space

21. Partial K space reconstruction