Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images...
-
Upload
erick-hutchinson -
Category
Documents
-
view
223 -
download
1
Transcript of Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images...
![Page 1: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/1.jpg)
Basic MRIBasic MRI
Chapter 1 LectureChapter 1 Lecture
![Page 2: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/2.jpg)
IntroductionIntroduction
MRI uses radio waves and a MRI uses radio waves and a magnetic field to make imagesmagnetic field to make images
Other methods make images in other Other methods make images in other waysways Radiography – x-ray attenuationRadiography – x-ray attenuation CT – x-ray with computerCT – x-ray with computer NM – gamma rays from radionuclidesNM – gamma rays from radionuclides US – sound wavesUS – sound waves
![Page 3: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/3.jpg)
MR ImagesMR Images
The image is a display of the radiofrequency The image is a display of the radiofrequency (RF) signal intensity(RF) signal intensity
The source of the RF signal from the patient is The source of the RF signal from the patient is the “condition of magnetization produced the “condition of magnetization produced when the patient is placed in the magnetic when the patient is placed in the magnetic field.”field.”
Magnetization occurs when magnetic nuclei Magnetization occurs when magnetic nuclei (like H nuclei or protons) are present(like H nuclei or protons) are present
Magnetization is changed during imaging, Magnetization is changed during imaging, and the rate of change depends on tissue and the rate of change depends on tissue characteristicscharacteristics
![Page 4: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/4.jpg)
Tissue CharacteristicsTissue Characteristics
PDPD T1T1 T2T2 FlowFlow DiffusionDiffusion Spectroscopy/chemical shiftSpectroscopy/chemical shift
![Page 5: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/5.jpg)
Major Tissue Major Tissue CharacteristicsCharacteristics
PD– proton densityPD– proton density T1– longitudinal relaxation time; T1– longitudinal relaxation time;
spin-lattice relaxation timespin-lattice relaxation time T2– transverse relaxation time; spin-T2– transverse relaxation time; spin-
spin relaxation timespin relaxation time
![Page 6: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/6.jpg)
Minor Tissue Minor Tissue CharacteristicsCharacteristics
FlowFlow DiffusionDiffusion Spectroscopy/chemical shiftSpectroscopy/chemical shift
![Page 7: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/7.jpg)
What do you see on an MR What do you see on an MR image?image?
RF signal intensity, influenced byRF signal intensity, influenced by Tissue magnetization, including Tissue magnetization, including
saturation pulsessaturation pulses Proton (hydrogen nuclei) densityProton (hydrogen nuclei) density Relaxation effects from T1 and T2Relaxation effects from T1 and T2
![Page 8: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/8.jpg)
Spatial CharacteristicsSpatial Characteristics
SlicesSlices VoxelsVoxels PixelsPixels
![Page 9: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/9.jpg)
Image QualityImage Quality
Detail/ResolutionDetail/Resolution Noise/Signal-to-Noise ratioNoise/Signal-to-Noise ratio ArtifactsArtifacts
![Page 10: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/10.jpg)
In-Plane ResolutionIn-Plane Resolution
This is a photo that This is a photo that has been taken at has been taken at 165x256 resolution165x256 resolution
![Page 11: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/11.jpg)
In-Plane ResolutionIn-Plane Resolution
This is a photo that This is a photo that has been taken has been taken with 329x512 with 329x512 resolutionresolution
![Page 12: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/12.jpg)
In-Plane ResolutionIn-Plane Resolution
Original Resolution Original Resolution 720x1150720x1150
![Page 13: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/13.jpg)
Signal-to-NoiseSignal-to-Noise
![Page 14: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/14.jpg)
Signal-to-NoiseSignal-to-Noise
![Page 15: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/15.jpg)
Signal-to-NoiseSignal-to-Noise
![Page 16: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/16.jpg)
Signal-to-NoiseSignal-to-Noise
![Page 17: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/17.jpg)
Aliasing: ExampleAliasing: Example
![Page 18: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/18.jpg)
Wraparound Artfacts in 3DWraparound Artfacts in 3D
![Page 19: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/19.jpg)
Chemical Shift EffectChemical Shift Effect
![Page 20: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/20.jpg)
Chemical Shift Chemical Shift
![Page 21: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/21.jpg)
Chemical Shift - ExampleChemical Shift - Example
![Page 22: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/22.jpg)
Chemical Shift ArtifactsChemical Shift Artifacts
![Page 23: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/23.jpg)
Signal TruncationSignal Truncation
![Page 24: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/24.jpg)
Truncation ArtifactsTruncation Artifacts
![Page 25: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/25.jpg)
Partial Volume EffectPartial Volume Effect
![Page 26: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/26.jpg)
Motion Artifacts - PeriodicMotion Artifacts - Periodic
![Page 27: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/27.jpg)
Motion Artifacts - PeriodicMotion Artifacts - Periodic
![Page 28: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/28.jpg)
Motion Artifacts - RandomMotion Artifacts - Random
![Page 29: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/29.jpg)
Flow Motion Artifacts - CSFFlow Motion Artifacts - CSF
![Page 30: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/30.jpg)
Magic Angle ArtifactsMagic Angle Artifacts
![Page 31: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/31.jpg)
FT of Realistic RF SignalFT of Realistic RF Signal
![Page 32: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/32.jpg)
RF Zipper ArtefactRF Zipper Artefact
![Page 33: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/33.jpg)
RF Feed through Zipper RF Feed through Zipper ArtifactArtifact
![Page 34: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/34.jpg)
RF NoiseRF Noise
![Page 35: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/35.jpg)
Magnetic Inhomogeneity Magnetic Inhomogeneity ArtifactsArtifacts
![Page 36: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/36.jpg)
Diamagnetic Susceptibility Diamagnetic Susceptibility ArtifactArtifact
![Page 37: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/37.jpg)
Paramagnetic Effect of Paramagnetic Effect of DeoxyhemoglobinDeoxyhemoglobin
![Page 38: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/38.jpg)
Ferromagnetic Ferromagnetic Susceptibility ArtifactsSusceptibility Artifacts
![Page 39: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/39.jpg)
Susceptibility ArtifactsSusceptibility Artifacts
![Page 40: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/40.jpg)
Gradient Non-linearityGradient Non-linearity
![Page 41: Basic MRI Chapter 1 Lecture. Introduction MRI uses radio waves and a magnetic field to make images MRI uses radio waves and a magnetic field to make images.](https://reader036.fdocuments.us/reader036/viewer/2022062423/5697c0141a28abf838ccd1d2/html5/thumbnails/41.jpg)
Geometric Distortion: Geometric Distortion: Gradient Non-LinearityGradient Non-Linearity