Introduction of Medical Imaging and MRI
-
Upload
cardiacinfo -
Category
Documents
-
view
533 -
download
3
description
Transcript of Introduction of Medical Imaging and MRI
![Page 1: Introduction of Medical Imaging and MRI](https://reader033.fdocuments.in/reader033/viewer/2022061215/549f46b3ac7959554c8b4800/html5/thumbnails/1.jpg)
Introduction of Medical Imaging
Chun Yuan
![Page 2: Introduction of Medical Imaging and MRI](https://reader033.fdocuments.in/reader033/viewer/2022061215/549f46b3ac7959554c8b4800/html5/thumbnails/2.jpg)
Organization of the Course
• 8 Lectures (1.5 hours per lecture)– Introduction of medical imaging and MRI– Basic concept of image formation– Basic pulse sequences and contrast manipulation– Image Reconstruction– RF pulse and gradient pulse– Fast imaging and advanced applications– MRI hardware– Functional MRI
![Page 3: Introduction of Medical Imaging and MRI](https://reader033.fdocuments.in/reader033/viewer/2022061215/549f46b3ac7959554c8b4800/html5/thumbnails/3.jpg)
Text Books
• Magnetic Resonance Imaging - Physical Principles and Sequence Design– ISBN: 0-471-35128-8– Authors: E. M. Haacke, R. W. Brown, M. R.
Thompson, and R. Venkatesan– Publisher: John Wiley and Sons, 1999
• Handbook of MRI Pulse Sequences– ISBN: 0-7803-4723-4– Authors: Bernstein, King, and Zhou– Publisher: Elsevier Publishing, 2004
![Page 4: Introduction of Medical Imaging and MRI](https://reader033.fdocuments.in/reader033/viewer/2022061215/549f46b3ac7959554c8b4800/html5/thumbnails/4.jpg)
Credits
• Home work– One for each day– 60%
• Term project– Topics will be provided– 40%
![Page 5: Introduction of Medical Imaging and MRI](https://reader033.fdocuments.in/reader033/viewer/2022061215/549f46b3ac7959554c8b4800/html5/thumbnails/5.jpg)
What is Medical Imaging• Introduce some form of radiation – electromagnetic– Acoustic
• Observe its interaction with tissue– attenuation– scattering / reflection– Concentration
• Convert the observations into a clinically meaningful image– film– computer
![Page 6: Introduction of Medical Imaging and MRI](https://reader033.fdocuments.in/reader033/viewer/2022061215/549f46b3ac7959554c8b4800/html5/thumbnails/6.jpg)
Electromagnetic Spectrum
![Page 7: Introduction of Medical Imaging and MRI](https://reader033.fdocuments.in/reader033/viewer/2022061215/549f46b3ac7959554c8b4800/html5/thumbnails/7.jpg)
Imaging Considerations
• Type of information– anatomical - from head to toe– functional - cardiac, brain, etc.– quantitative vs. qualitative
• Limitations– resolution– sensitive range (e.g. view angles)– speed– cost– invasiveness
![Page 8: Introduction of Medical Imaging and MRI](https://reader033.fdocuments.in/reader033/viewer/2022061215/549f46b3ac7959554c8b4800/html5/thumbnails/8.jpg)
“Classical” methods
• Projection Radiography (Conventional X-ray)• Ultrasound• Conventional Nuclear Medicine
Images that are direct manifestations of the interactionbetween radiation and tissue
![Page 9: Introduction of Medical Imaging and MRI](https://reader033.fdocuments.in/reader033/viewer/2022061215/549f46b3ac7959554c8b4800/html5/thumbnails/9.jpg)
Projection Radiography
• Physical Principle: Variation in X-ray attenuation of different tissues
• Methodology: A beam of X-rays is directed through a patient onto a film.
• Image: An X-ray “shadow” of the patient.• History:– Roentgen’s discovery - 1895– Application to medicine – 1896– contrast materials - early 1900’s– angiography - 1927
![Page 10: Introduction of Medical Imaging and MRI](https://reader033.fdocuments.in/reader033/viewer/2022061215/549f46b3ac7959554c8b4800/html5/thumbnails/10.jpg)
Projection Radiography System
![Page 11: Introduction of Medical Imaging and MRI](https://reader033.fdocuments.in/reader033/viewer/2022061215/549f46b3ac7959554c8b4800/html5/thumbnails/11.jpg)
Projection Radiography Examples
Chest X-Ray
Mammogram
Angiogram
![Page 12: Introduction of Medical Imaging and MRI](https://reader033.fdocuments.in/reader033/viewer/2022061215/549f46b3ac7959554c8b4800/html5/thumbnails/12.jpg)
Ultrasound
• Physical Principle: Ultrasound waves scatter and reflect within the body
• Methodology: A pulse of ultrasonic energy is propagated into the body and backscattered echoes record the depth of objects in the body.
• Image: A “depth map” of patient organs.• History:– Concept derived from W.W.II sonar– Major clinical development - 1970’s
![Page 13: Introduction of Medical Imaging and MRI](https://reader033.fdocuments.in/reader033/viewer/2022061215/549f46b3ac7959554c8b4800/html5/thumbnails/13.jpg)
Ultrasound System
![Page 14: Introduction of Medical Imaging and MRI](https://reader033.fdocuments.in/reader033/viewer/2022061215/549f46b3ac7959554c8b4800/html5/thumbnails/14.jpg)
Ultrasound Mode
• B-mode image– Longitudinal view of digital artery– Frequency: 40MHz– Resolution: up to 50mm
• Doppler– Flow velocity in digital artery
![Page 15: Introduction of Medical Imaging and MRI](https://reader033.fdocuments.in/reader033/viewer/2022061215/549f46b3ac7959554c8b4800/html5/thumbnails/15.jpg)
Nuclear Medicine
• Physical Principle: Variable uptake of radioactive materials by different organs
• Methodology: Inject patient with radiolabeled substance and record time-space pattern of radiation.
• Image: A map of the radioactivity of the patient.• History:– Therapeutic administration of radiolabeled substances -
1950– Scintillation camera - 1952
![Page 16: Introduction of Medical Imaging and MRI](https://reader033.fdocuments.in/reader033/viewer/2022061215/549f46b3ac7959554c8b4800/html5/thumbnails/16.jpg)
Nuclear Medicine System
![Page 17: Introduction of Medical Imaging and MRI](https://reader033.fdocuments.in/reader033/viewer/2022061215/549f46b3ac7959554c8b4800/html5/thumbnails/17.jpg)
Nuclear Medicine Example
![Page 18: Introduction of Medical Imaging and MRI](https://reader033.fdocuments.in/reader033/viewer/2022061215/549f46b3ac7959554c8b4800/html5/thumbnails/18.jpg)
“Computed” methods
• Computed Tomography (CT)– X-ray CT– PET– SPECT
• Magnetic Resonance Imaging• (3D Ultrasound)
Images that are formed using mathematical methods and computers from indirect measurements of the
interaction between radiation and tissue
![Page 19: Introduction of Medical Imaging and MRI](https://reader033.fdocuments.in/reader033/viewer/2022061215/549f46b3ac7959554c8b4800/html5/thumbnails/19.jpg)
Computed Tomography
• Physical Principle: Projection slice theorem dictates how to reconstruct a 2-D image from multiple 1-D projections (Radon Transform).
• Methodology: Obtain multiple projection images and reconstruct images using a computer.
• Image: A 2-D slice mapping the patient’s X-ray attenuation coefficient (X-ray CT) or radioactivity (PET and SPECT).
• History:– X-ray CT proposed - mid 1960’s– Early clinical use - 1972– PET and SPECT followed X-ray CT
![Page 21: Introduction of Medical Imaging and MRI](https://reader033.fdocuments.in/reader033/viewer/2022061215/549f46b3ac7959554c8b4800/html5/thumbnails/21.jpg)
X-ray CT Example
![Page 22: Introduction of Medical Imaging and MRI](https://reader033.fdocuments.in/reader033/viewer/2022061215/549f46b3ac7959554c8b4800/html5/thumbnails/22.jpg)
PET Example
![Page 23: Introduction of Medical Imaging and MRI](https://reader033.fdocuments.in/reader033/viewer/2022061215/549f46b3ac7959554c8b4800/html5/thumbnails/23.jpg)
Magnetic Resonance Imaging
• Physical Principle: Within a strong magnetic field, paramagnetic nuclei (usually hydrogen protons) will resonate in response to RF radiation
• Methodology: Place patient in a magnet, irradiate with RF field, and record spatially encoded RF echoes.
• Image: A map of proton concentration through a slice of the body.
• History:– NMR discovered - 1940’s– Imaging proposed in 1972– Current generation of machines developed in 1980’s
![Page 24: Introduction of Medical Imaging and MRI](https://reader033.fdocuments.in/reader033/viewer/2022061215/549f46b3ac7959554c8b4800/html5/thumbnails/24.jpg)
Nobel Prize for MRI
![Page 25: Introduction of Medical Imaging and MRI](https://reader033.fdocuments.in/reader033/viewer/2022061215/549f46b3ac7959554c8b4800/html5/thumbnails/25.jpg)
MRI System
![Page 26: Introduction of Medical Imaging and MRI](https://reader033.fdocuments.in/reader033/viewer/2022061215/549f46b3ac7959554c8b4800/html5/thumbnails/26.jpg)
MRI Example
![Page 27: Introduction of Medical Imaging and MRI](https://reader033.fdocuments.in/reader033/viewer/2022061215/549f46b3ac7959554c8b4800/html5/thumbnails/27.jpg)
Star Artifacts in CT
![Page 28: Introduction of Medical Imaging and MRI](https://reader033.fdocuments.in/reader033/viewer/2022061215/549f46b3ac7959554c8b4800/html5/thumbnails/28.jpg)
Shadow Artifacts in Ultrasound
![Page 29: Introduction of Medical Imaging and MRI](https://reader033.fdocuments.in/reader033/viewer/2022061215/549f46b3ac7959554c8b4800/html5/thumbnails/29.jpg)
Wrap-around Artifacts in MRI