1. Image reproduction +fMRI

3. Filtered Back Projection

5. 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 ’ (,  ).

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

7. Phase encoding

8. K space

9. K Space

10. Partial K space reconstruction

13. Zero padding

14. Conjugate symmetry

16. Homodyne reconstruction

20. Mechanism of BOLD Functional MRI Brain activity Oxygen consumptionCerebral blood flow Oxyhemoglobin Deoxyhemoglobin Magnetic susceptibility T2* MRI signal intesity

21. Magnetic Properties of Oxyhemoglobin and Deoxyhemoglobin Deoxyhemoglobin: paramagnetic (  > 0) paramagnetic with respect to the surrounding tissue Oxyhemoglobin: diamagnetic (  < 0) isomagnetic with respect to the surrounding tissue

22. T 2 * Effect in fMRI excitation reception MR signal (S) action rest TE t

23. Time Series and Activation Maps Off On Scan Number Signal Intensity

24. Temporal resolution  Impulse-response function 2s 5s 12s

25. PCA_IMAGE: PCA of time  space: 1: exclude first frames 2: drift 3: long-range correlation or anatomical effect: remove by converting to % of brain 4: signal?