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Basics of MRI
Vinai Roopchansingh
Functional MRI Facility, National Institute of Mental Health, National Institutes of Health,DHHS
June 10, 2016
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 1 / 22
Outline
1 MRI System Overview
2 MRI - Breaking down the acronymMagneticResonanceImaging
3 ContrastBasic tissue contrastBOLD contrastOther contrasts
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 2 / 22
Outline
1 MRI System Overview
2 MRI - Breaking down the acronymMagneticResonanceImaging
3 ContrastBasic tissue contrastBOLD contrastOther contrasts
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 3 / 22
MRI system block diagram
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 4 / 22
Outline
1 MRI System Overview
2 MRI - Breaking down the acronymMagneticResonanceImaging
3 ContrastBasic tissue contrastBOLD contrastOther contrasts
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 5 / 22
Magnetic
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 6 / 22
Magnetic
Certain nuclei (odd number of protons and/or neutrons) havemagnetic properties (i.e. magnetic moment - 1952 Nobel Prize inPhysics, to Bloch and Purcell).
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 6 / 22
Magnetic
Certain nuclei (odd number of protons and/or neutrons) havemagnetic properties (i.e. magnetic moment - 1952 Nobel Prize inPhysics, to Bloch and Purcell).
Includes 13C, 23Na, 31P, 129Xe, and ...
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 6 / 22
Magnetic
Certain nuclei (odd number of protons and/or neutrons) havemagnetic properties (i.e. magnetic moment - 1952 Nobel Prize inPhysics, to Bloch and Purcell).
Includes 13C, 23Na, 31P, 129Xe, and ...
1H !
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 6 / 22
Magnetic
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 7 / 22
Magnetic
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 7 / 22
Magnetic
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 7 / 22
Magnetic
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 7 / 22
Planck and Larmor Equations
E = hν = hf0
2πf0 = ω0 = γB0
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 8 / 22
https://www.youtube.com/playlist?list=PLAE12114468910462
(Tyler Moore - Videos for MR Tutorial)
Precession
Resonance and excitation
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 9 / 22
Imaging (location encoding with gradients)
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 10 / 22
Imaging (location encoding with gradients)
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 10 / 22
Imaging (location encoding with gradients)
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 10 / 22
Imaging (location encoding with gradients)
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 10 / 22
Slice Encoding/Selection
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 11 / 22
Slice Encoding/Selection
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 11 / 22
Frequency Encoding
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 12 / 22
Frequency Encoding
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 12 / 22
Creating image from signal
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 13 / 22
Creating image from signal
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 13 / 22
Creating image from signal
s(t) =∫~rMxy(~r , 0)e
−i2π~k(t)·~rd~r
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 14 / 22
Creating image from signal
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 15 / 22
Creating image from signal
Data acquisition in “Fourier domain” encoded with spatial gradients.
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 15 / 22
Creating image from signal
Data acquisition in “Fourier domain” encoded with spatial gradients.
Fourier transform acquired data to give image.
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 15 / 22
Creating image from signal
Data acquisition in “Fourier domain” encoded with spatial gradients.
Fourier transform acquired data to give image.
Nobel Prize in Physiology or Medicine in 2003 to Lauterbur andMansfield.
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 15 / 22
Creating image from signal
Paper on Fourier Transform in MR: DOI:10.2214/AJR.07.2874
American Journal of Roentgenology, 2008, Vol 5, 1396-1405
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 16 / 22
Outline
1 MRI System Overview
2 MRI - Breaking down the acronymMagneticResonanceImaging
3 ContrastBasic tissue contrastBOLD contrastOther contrasts
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 17 / 22
Relaxation times
https://www.youtube.com/playlist?list=PLAE12114468910462
(Tyler Moore - Videos for MR Tutorial)
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 18 / 22
Relaxation times
https://www.youtube.com/playlist?list=PLAE12114468910462
(Tyler Moore - Videos for MR Tutorial)
Transverse (a.k.a T2) relaxation
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 18 / 22
Relaxation times
https://www.youtube.com/playlist?list=PLAE12114468910462
(Tyler Moore - Videos for MR Tutorial)
Transverse (a.k.a T2) relaxation
Longitudinal (a.k.a T1) relaxation
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 18 / 22
Basic tissue contrast
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 19 / 22
Basic tissue contrast
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 19 / 22
Basic tissue contrast
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 19 / 22
Basic tissue contrast
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 19 / 22
BOLD contrast
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 20 / 22
BOLD contrast
PNAS, 1990 Vol 87(24):9868-9872 - Ogawa et.al .
PNAS, 1992 Vol 89(12):5675-5679 - Kwong et.al .
MRM, 1992 Vol 25:390-397 - Bandettini et.al .
PNAS, 1992 Vol 89(13):5951-5955 - Ogawa et.al .
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 20 / 22
BOLD contrast
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 21 / 22
BOLD contrast
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 21 / 22
BOLD contrast
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 21 / 22
BOLD contrast
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 21 / 22
Other types of contrast
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 22 / 22
Other types of contrast
Nature Reviews Neuroscience 4, 469-480 (June 2003) -DOI:10.1038/nrn1119 - Diffusion imaging (review paper)
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 22 / 22
Other types of contrast
Nature Reviews Neuroscience 4, 469-480 (June 2003) -DOI:10.1038/nrn1119 - Diffusion imaging (review paper)
PNAS, 2007 Vol 104(28):11796-11801 - Duyn et.al . - Phase imaging
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 22 / 22
Other types of contrast
Nature Reviews Neuroscience 4, 469-480 (June 2003) -DOI:10.1038/nrn1119 - Diffusion imaging (review paper)
PNAS, 2007 Vol 104(28):11796-11801 - Duyn et.al . - Phase imaging
MRM, 1992 Vol 23:37-45 - Detre et.al . - Perfusion imaging
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 22 / 22
Other types of contrast
Nature Reviews Neuroscience 4, 469-480 (June 2003) -DOI:10.1038/nrn1119 - Diffusion imaging (review paper)
PNAS, 2007 Vol 104(28):11796-11801 - Duyn et.al . - Phase imaging
MRM, 1992 Vol 23:37-45 - Detre et.al . - Perfusion imaging
MRM, 1989 Vol 10:135-144 - Wolff and Balaban - MagnetizationTransfer
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 22 / 22
Other types of contrast
Nature Reviews Neuroscience 4, 469-480 (June 2003) -DOI:10.1038/nrn1119 - Diffusion imaging (review paper)
PNAS, 2007 Vol 104(28):11796-11801 - Duyn et.al . - Phase imaging
MRM, 1992 Vol 23:37-45 - Detre et.al . - Perfusion imaging
MRM, 1989 Vol 10:135-144 - Wolff and Balaban - MagnetizationTransfer
...
Vinai R. (FMRIF/NIMH/NIH/DHHS) MRI Basics 2016.06.10 22 / 22
