1 / 100

Functional MRI Mechanisms and Limits

Functional MRI Mechanisms and Limits. bandettini@nih.gov. Peter A. Bandettini, Ph.D Unit on Functional Imaging Methods & 3T Neuroimaging Core Facility Laboratory of Brain and Cognition National Institute of Mental Health. Engineering. Computer Science. Physics. Statistics. Cognitive

rosaliej
Download Presentation

Functional MRI Mechanisms and Limits

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Functional MRI Mechanisms and Limits bandettini@nih.gov Peter A. Bandettini, Ph.D Unit on Functional Imaging Methods & 3T Neuroimaging Core Facility Laboratory of Brain and Cognition National Institute of Mental Health

  2. Engineering Computer Science Physics Statistics Cognitive Science Physiology Medicine Technology Methodology Neuroscience Interpretation Applications

  3. Diff. tensor Technology Mg+ 7T >8 channels 1.5T,3T, 4T EPI on Clin. Syst. Venography Real time fMRI EPI SENSE Nav. pulses “vaso” Local Human Head Gradient Coils Quant. ASL Z-shim Baseline Susceptibility MRI Dynamic IV volume Spiral EPI ASL Current Imaging? BOLD Simultaneous ASL and BOLD Multi-shot fMRI Correlation Analysis CO2 Calibration Methodology Motion Correction Latency and Width Mod Parametric Design Multi-Modal Mapping Surface Mapping Baseline Volume Free-behavior Designs ICA Phase Mapping Mental Chronometry Multi-variate Mapping Linear Regression IVIM Deconvolution Fuzzy Clustering Event-related BOLD models PET correlation Interpretation IV vs EV ASL vs. BOLD Layer spec. latency Bo dep. Pre-undershoot PSF of BOLD TE dep Resolution Dep. Excite and Inhibit Extended Stim. Blood T2 Post-undershoot Metab. Correlation Linearity SE vs. GE CO2 effect Optical Im. Correlation Hemoglobin Fluctuations NIRS Correlation Balloon Model Electrophys. correlation Inflow Veins Complex motor Applications Memory Imagery Emotion Language Children Drug effects Motor learning Tumor vasc. Mirror neurons BOLD -V1, M1, A1 Presurgical Ocular Dominance Attention Volume - Stroke Clinical Populations V1, V2..mapping Priming/Learning D Volume-V1 Performance prediction Plasticity Face recognition 36 82 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03

  4. Blood Volume Imaging Susceptibility Contrast agent bolus injection and time series collection of T2* or T2 - weighted images

  5. Blood Oxygenation Imaging task task • 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.

  6. PET DCBF>>DCMRO2 - - The vascular response Factors influencing [Deoxy-Hb] concentration Oxygen consumption Blood Volume + + [Deoxy- Hb] Blood Flow Velocity Courtesy of Arno Villringer

  7. Time course of BOLD signal Yacoub E, Le TH, Ugurbil K, Hu X (1999) Magn Res Med 41(3):436-41 Courtesy of Arno Villringer

  8. Blood Perfusion Imaging EPISTAR FAIR . . . - - - - Perfusion Time Series . . .

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

  10. 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.

  11. Simultaneous BOLD and Perfusion BOLD Perfusion

  12. MAGNET RESON MED 50 (2): 263-274 AUG 2003

  13. 5% CO2 12% O2 Effect of Hemodynamic Stress on BOLD Contrast 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).

  14. 40 30 20 10 0 % -10 -20 -30 -40 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

  15. The Problem Measured Signal Neuronal Activation ? ? ? ? Hemodynamics Noise

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

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

  18. Single Shot EPI T2* decay EPI Readout Window ≈ 20 to 40 ms

  19. P. A. Bandettini, Functional MRI temporal resolution in "Functional MRI" (C. Moonen, and P. Bandettini., Eds.), p. 205-220, Springer - Verlag,. 1999.

  20. First Event-related fMRI Results 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.

  21. 1000 msec 100 msec 34 msec 5 10 15 20 Time (sec) R. L. Savoy, et al., Pushing the temporal resolution of fMRI: studies of very brief visual stimuli, onset variability and asynchrony, and stimulus-correlated changes in noise [oral], 3'rd Proc. Soc. Magn. Reson., Nice, p. 450. (1995).

  22. Bandettini, et al., The functional dynamics of blood oxygenation level contrast in the motor cortex, 12'th Proc. Soc. Magn. Reson. Med., New York, p. 1382. (1993).

  23. The major obstacle in BOLD contrast temporal resolution: + 2 sec Latency - 2 sec Magnitude Venogram P. A. Bandettini, The temporal resolution of Functional MRI in "Functional MRI" (C. Moonen, and P. Bandettini., Eds.), p. 205-220, Springer - Verlag,. 1999.

  24. A tangent into venograms (3 Tesla)

  25. MP-RAGE 3D T-O-F MRA 3D Venous PC MR Venogram

  26. Hemi-Field Experiment 9.0 seconds 15 seconds 500 msec 500 msec 20 30 10 Time (seconds) Right Hemisphere Left Hemisphere

  27. 0 10 20 30 500 ms 500 ms RightHemifield Left Hemifield + 2.5 s - = 0 s - 2.5 s

  28. Cognitive Neuroscience Application: PNAS

  29. A A A B B B Word vs. Non-word 0o, 60o, 120o Rotation Regions of Interest Inferior Frontal Gyrus Precentral Gyrus Middle Temporal Gyrus

  30. No calibration Formisano, E. and R. Goebel, Tracking cognitive processes with functional MRI mental chronometry. Current Opinion in Neurobiology, 2003. 13: p. 174-181.

  31. 11026–11031 PNAS September 26, 2000vol. 97 no. 20

  32. BOLD Flow P. A. Bandettini, K. K. Kwong, T. L. Davis, R. B. H. Tootell, E. C. Wong, P. T. Fox, J. W. Belliveau, R. M. Weisskoff, B. R. Rosen, (1997). “Characterization of cerebral blood oxygenation and flow changes during prolonged brain activation.” Human Brain Mapping 5, 93-109.

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

  34. Single Shot Imaging T2* decay EPI Readout Window ≈ 20 to 40 ms

  35. T2* decay EPI Window Partial k-space imaging

  36. Partial k-space imaging Jesmanowicz, P. A. Bandettini, J. S. Hyde, (1998) “Single shot half k-space high resolution EPI for fMRI at 3T.” Magn. Reson. Med. 40, 754-762.

  37. T2* decay EPI Window 1 Multishot Imaging T2* decay EPI Window 2

  38. Multi Shot EPI Excitations 1 2 4 8 Matrix Size 64 x 64 128 x 128 256 x 128 256 x 256

  39. SENSE Imaging ≈ 5 to 30 ms Pruessmann, et al.

  40. 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.

  41. 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.

  42. Arterial inflow (BOLD TR < 500 ms) Venous inflow (for ASL, w/ no VN) Pulse Sequence Sensitivity Spatial Heterogeneity

  43. Menon, et al ODC Maps using fMRI 1 cm calcarine • Identical in size, orientation, and appearance to those obtained by optical imaging1 and histology3,4. 1Malonek D, Grinvald A. Science 272, 551-4 (1996). 3Horton JC, Hocking DR. J Neurosci 16, 7228-39 (1996). 4Horton JC, et al. Arch Ophthalmol 108, 1025-31 (1990).

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

  45. NeuroImage,19: 132-144, (2003).

  46. 8 Channel Array Quadrature Head Coil SNR 128 x 96 64 x 48 TSNR 128 x 96

  47. 1000 800 600 400 200 0 200 400 600 800 1000 Temporal S/N vs. Image S/N PHANTOMS SUBJECTS 1400 1200 1000 800 600 400 200 Temporal S/N Temporal S/N 0 200 400 600 800 1000 1200 1400 Image S/N Image S/N N. Petridou

More Related