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| + | Magnetic Resonance Imaging (MRI) | ||
| − | + | Definition | |
| + | * Can be very high resolution | ||
| + | * No exposure to ionizing radiation | ||
| + | * Very flexible and programmable | ||
| + | * Tends to be expensive, noisy, and slow | ||
| + | [[Image:intro_fig4.jpeg|400px|thumb|left|Fig 1: The exterior of an MRI scanner]] | ||
| + | |||
| + | |||
| + | [[Image:intro_fig4.jpeg|400px|thumb|left|Fig 2: MRI scan of a patient]] | ||
| + | |||
| + | |||
| + | ==MRI Attributes== | ||
| + | |||
| + | * Based on magnetic resonance effect in atomic species | ||
| + | * Does not requires any ionizing radiation | ||
| + | * Numerous modalitites | ||
| + | ** Conventional anatomical scans | ||
| + | ** Functional MRI(fMRI) | ||
| + | ** MRI Tagging | ||
| + | *Image formation | ||
| + | ** RF excitation of magnetic resonance modes | ||
| + | ** Magnetic field gradients modulate resonance frequency | ||
| + | ** Reconstruction computed with inverse Fourier transform | ||
| + | ** Fully programmable | ||
| + | ** Requires an enormous (and very expensive) superconducting magnet | ||
| + | |||
| + | |||
| + | ---- | ||
| + | |||
| + | == Magnetic Resonance == | ||
| + | |||
| + | [[Image:intro_fig4.jpeg|400px|thumb|left|Fig 3: Precession of atom in the presence of a magnetic field]] | ||
| + | |||
| + | * Atom will precess at the Lamor frequency <br/> | ||
| + | <math>\omega_0 = LM \ </math><br/> | ||
| + | where <br/> | ||
| + | <math>M</math> is the magnitude of the ambient magnetic field <br/> | ||
| + | <math>\omega_0</math> is the frequency of precession in radians per second<br/> | ||
| + | <math>L</math> is the Lamor constant and its value depends on the choice of atom<br/> | ||
| + | |||
| + | |||
| + | ---- | ||
| + | |||
| + | == The MRI Magnet == | ||
| + | |||
| + | [[Image:intro_fig4.jpeg|400px|thumb|left|Fig 4: The MRI magnet]] | ||
| + | |||
| + | |||
| + | *Large superconducting magnet | ||
| + | ** Uniform field within bore | ||
| + | ** Very large static magnetic field | ||
Revision as of 06:40, 7 June 2013
- ↳ Topic 3: Magnetic Resonance Imaging
The Bouman Lectures on Image Processing
A sLecture by Maliha Hossain
Topic 3: Magnetic Resonance Imaging
© 2013
Contents
Excerpt from Prof. Bouman's Lecture
Accompanying Lecture Notes
Magnetic Resonance Imaging (MRI)
Definition
- Can be very high resolution
- No exposure to ionizing radiation
- Very flexible and programmable
- Tends to be expensive, noisy, and slow
MRI Attributes
- Based on magnetic resonance effect in atomic species
- Does not requires any ionizing radiation
- Numerous modalitites
- Conventional anatomical scans
- Functional MRI(fMRI)
- MRI Tagging
- Image formation
- RF excitation of magnetic resonance modes
- Magnetic field gradients modulate resonance frequency
- Reconstruction computed with inverse Fourier transform
- Fully programmable
- Requires an enormous (and very expensive) superconducting magnet
Magnetic Resonance
- Atom will precess at the Lamor frequency
$ \omega_0 = LM \ $
where
$ M $ is the magnitude of the ambient magnetic field
$ \omega_0 $ is the frequency of precession in radians per second
$ L $ is the Lamor constant and its value depends on the choice of atom
The MRI Magnet
- Large superconducting magnet
- Uniform field within bore
- Very large static magnetic field
References
- C. A. Bouman. ECE 637. Class Lecture. Digital Image Processing I. Faculty of Electrical Engineering, Purdue University. Spring 2013.
- G. Francis. Psy 200. "Introduction to Cognitive Psychology". Class Lecture Notes. Faculty of Psychological Sciences, Purdue University. Spring 2013.
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