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Magnetic Resonance Imaging of Human Brain Function: Methods, Issues, and Opportunities

Discover methods, challenges, and opportunities in functional MRI brain imaging. Explore contrast types, activation techniques, and applications of fMRI technology.

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Magnetic Resonance Imaging of Human Brain Function: Methods, Issues, and Opportunities

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  1. Magnetic Resonance Imaging of Human Brain Function: Methods, Issues, and Opportunities Peter A. Bandettini Unit on Functional Imaging Methods & Functional MRI Facility Laboratory of Brain and Cognition National Institute of Mental Health

  2. Functional Neuroimaging Techniques Non-invasive Log Size (mm) Invasive Log Time (sec)

  3. Types of Functional MRI Contrast • Blood Volume • BOLD • Perfusion • CMRO2

  4. Bulk Susceptibility Contrast

  5. Types of Functional MRI Contrast • Blood Volume • BOLD • Perfusion • CMRO2

  6. H2O Addition of paramagnetic compound to blood

  7. GE contrast GE TE = 30 ms SE 2.5 to 3 µm 3 to 15 µm 15 to ∞ µm SE TE = 110 ms compartment size

  8. Activation-Induced Blood Volume Change

  9. Blood Volume

  10. Types of Functional MRI Contrast • Blood Volume • BOLD • Perfusion • CMRO2

  11. L. Pauling, C. D. Coryell, (1936) “The magnetic properties and structure of hemoglobin, oxyhemoglobin, and carbonmonoxyhemoglobin.” Proc.Natl. Acad. Sci. USA22, 210-216. Thulborn, K. R., J. C. Waterton, et al. (1982).“Oxygenation dependence of the transverse relaxation time of water protons in whole blood at high field.” Biochim. Biophys. Acta. 714: 265-270. S. Ogawa, T. M. Lee, A. R. Kay, D. W. Tank, (1990) “Brain magnetic resonance imaging with contrast dependent on blood oxygenation.” Proc. Natl. Acad. Sci. USA 87, 9868-9872. R. Turner, D. LeBihan, C. T. W. Moonen, D. Despres, J. Frank, (1991). Echo-planar time course MRI of cat brain oxygenation changes. Magn. Reson. Med. 27, 159-166.

  12. BOLD Contrast in the Detection of Neuronal Activity Cerebral Tissue Activation Local Vasodilation Oxygen Delivery Exceeds Metabolic Need Increase in Cerebral Blood Flow and Volume Increase in Capillary and Venous Blood Oxygenation Deoxy-hemoglobin: paramagnetic Oxy-hemoglobin: diamagnetic Decrease in Deoxy-hemoglobin Decrease in susceptibility-related intravoxel dephasing Increase in T2 and T2* Local Signal Increase in T2 and T2* - weighted sequences

  13. Alternating Left and Right Finger Tapping ~1992 K. K. Kwong, et al, (1992) “Dynamic magnetic resonance imaging of human brain activity during primary sensory stimulation.” Proc. Natl. Acad. Sci. USA. 89, 5675-5679. S. Ogawa, et al., (1992) “Intrinsic signal changes accompanying sensory stimulation: functional brain mapping with magnetic resonance imaging. Proc. Natl. Acad. Sci. USA.” 89, 5951-5955. P. A. Bandettini, et al., (1992) “Time course EPI of human brain function during task activation.” Magn. Reson. Med 25, 390-397. Blamire, A. M., et al. (1992). “Dynamic mapping of the human visual cortex by high-speed magnetic resonance imaging.” Proc. Natl. Acad. Sci. USA 89: 11069-11073.

  14. Correlation analysis, Fourier analysis, t-test, f-test…

  15. GE contrast SE 2.5 to 3 µm 3 to 15 µm 15 to ∞ µm compartment size

  16. Finger Movement Left Right

  17. Toe Movement Left Right

  18. Finger Movement Tactile Stimulation

  19. Imagined Complex Right Simple Right Complex Right Imagined Complex Left Simple Left Complex Left

  20. Reading

  21. Listening to Spoken Words

  22. BOLD dynamics activation activation

  23. time Anatomic Functional

  24. Single Shot Echo Planar Imaging (EPI) T2* decay EPI Readout Window ≈ 20 to 40 ms

  25. Imaging System Components Magnet RF Receiver Viewing Console X Y Z RF Transmitter Scan Controller Gradient Power Systems

  26. 1991-1992 1992-1999

  27. Imaging System Components Magnet RF Receiver Viewing Console X Y Z RF Transmitter Scan Controller Gradient Power Systems

  28. General Electric 3 Tesla Scanner

  29. Types of Functional MRI Contrast • Blood Volume • BOLD • Perfusion • CMRO2

  30. Blood Perfusion EPISTAR FAIR . . . - - - - Perfusion Time Series . . .

  31. TI (ms) 200 400 600 800 1000 1200 FAIR EPISTAR

  32. Williams, D. S., Detre, J. A., Leigh, J. S. & Koretsky, A. S. (1992) “Magnetic resonance imaging of perfusion using spin-inversion of arterial water.” Proc. Natl. Acad. Sci. USA 89, 212-216. Edelman, R., Siewert, B. & Darby, D. (1994) “Qualitative mapping of cerebral blood flow and functional localization with echo planar MR imaging ans signal targeting with alternating radiofrequency (EPISTAR).” Radiology 192, 1-8. Kim, S.-G. (1995) “Quantification of relative cerebral blood flow change by flow-sensitive alternating inversion recovery (FAIR) technique: application to functional mapping.” Magn. Reson. Med. 34, 293-301. Kwong, K. K. et al. (1995) “MR perfusion studies with T1-weighted echo planar imaging.”Magn. Reson. Med. 34, 878-887.

  33. Comparison with Positron Emission Tomography PET: H215O MRI: ASL

  34. Perfusion Rest Activation BOLD P. A. Bandettini, E. C. Wong, Magnetic resonance imaging of human brain function: principles, practicalities, and possibilities, in "Neurosurgery Clinics of North America: Functional Imaging" (M. Haglund, Ed.), p.345-371, W. B. Saunders Co., 1997.

  35. Anatomy BOLD Perfusion P. A. Bandettini, E. C. Wong, Magnetic resonance imaging of human brain function: principles, practicalities, and possibilities, in "Neurosurgery Clinics of North America: Functional Imaging" (M. Haglund, Ed.), p.345-371, W. B. Saunders Co., 1997.

  36. Types of Functional MRI Contrast • Blood Volume • BOLD • Perfusion • CMRO2

  37. 5% CO2 12% O2 Hemodynamic Stress Calibration P. A. Bandettini, E. C. Wong, A hypercapnia - based normalization method for improved spatial localization of human brain activation with fMRI. NMR in Biomedicine 10, 197-203 (1997).

  38. 20 3 15 2 10 BOLD (% increase) CBF (% increase) 5 1 0 0 -5 -10 0 200 400 600 800 1000 1200 1400 0 200 400 600 800 1000 1200 1400 Time (seconds) Time (seconds) CBF BOLD Simultaneous Perfusion and BOLD imaging during graded visual activation and hypercapnia N=12

  39. Computed CMRO2 Changes 40 30 20 10 0 % % -10 -20 -30 -40 Subject 2 Subject 1 R. Hoge et al.

  40. Direct Neuronal Current Imaging?

  41. Preliminary models suggest that magnetic field changes on the order of 0.1 to 1 nT are induced (at the voxel scale) in the brain. • These changes induce about a 0.01 Hz frequency shift or 0.09 deg (@ TE = 30 ms) phase shift. • Question: Is this detectable?

  42. Z X BR<2nT BR<0.2nT

  43. 25 mV 10 s In Vitro Results Newborn rat brains have been found to exhibit spontaneous and synchronous firing at specific frequencies Cortex Striatum Subthalamic nucleus Globus Pallidus Plenz, D. and S.T. Kital. Nature, 1999. 400: p. 677-682.

  44. 1 2 Results Culture CSF CSF Culture # # * * * * FSE image Hz Hz Active state: 10 min, Inactive state: 10 min after TTX admin. *: activity #: scanner pump frequency Petridou et al.

  45. Latest Developments… • Temporal Resolution • Spatial Resolution • Sensitivity and Noise • Information Content • Implementation

  46. Latest Developments… • Temporal Resolution • Spatial Resolution • Sensitivity and Noise • Information Content • Implementation

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