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1. - Dr Nisar Ahmed Arain
Assistant Professor
Anesthesia/Critical Care/ER
-M.R.I
MAGNETIC RESONING IMAGING

2. MRI is a radiological technique
Its Uses
a-Magnetism
b-Radio waves and a
c-Computer
d-to produce images of body structures
e--MRI is based on the principals of
NMR(Nuclear Medical Resonance)
The First Human examination of MRI
was performed in 1997 and
it took 5 hours to produce an image
- MRI

3. -MRI MACHIINE

4. -Magnetic Resonance Imaging Inventor
-FATHER OF MRI

5. 1-Most ailments of the Brain, including Tumors
and sport Injuries
2-Musculo skeletal problems
3-Most spinal conditions, injuries, Vascular
abnormalities
4-Female Pelvic problems
5-Prostate problems
6-Abnormal Gastro Intestinal tract conditions
7-Ear, Nose, and Throat conditions
8-Soft tissue and Bone Pathological conditions
-WHAT CAN BE DIAGNOSED
BY AN MRI SCAN

6. 1-A Cardiac Pacemaker
2-Certain Dips in your head from Brain
operations
3-A Cochlear implant
4-A metallic foreign body in your Eye
where you had surgery in last 8 weeks
5-If you are Pregnant
-WHO CAN HAVE AN
MRI SCAN

7. 1-MRI makes use of the magnetic
properties of certain atomic
nuclei
2-Hydrogen nucleus (single proton)
present in the water molecules and
therefore all body tissues
3-The hydrogen Nuclei partially
aligned by a strong magnetic field
in the scanner.
-PRINCIPLES OF MRI

8. -PRINCIPLES OF MRI cont.
4-The nuclei can be rotated using
radio waves, and they subsequently
oscillate in the magnetic field while
returning to equilibrium
5-Simultaneously they emit a radio
signal, and this is detected using
antenna (coils)
6-Very detailed images can be made of
soft tissues

9. Randomly arranged
Hydrogen Atoms
-PRINCIPLES OF MRI cont.
After the application of strong
magnetic field

10. -PRINCIPLES OF MRI cont.

11. 1-Scanner
2-Computer
3-Recording Hardware
-MAIN COMPONENTS OF MRI

12. 1- An MRI Scanner is a large tube
that contains powerful magnets
2-Main components of scanner are
a-Static Magnetic field coils
b-Gradient coils
c-RF (radio frequency) coils
-SCANNER

13. -MRI SCANNER CUTAWAY

14. 1-Three methods to generate magnetic field
a-Fixed Magnet
b-Resistive Magnet
c-Super conducting Magnet
2-Fixed Magnets and Resistive Magnets are generally
restricted to field strengths below 0.4t
3-High resolution imaging systems use super conducting
Magnets
4-They need coils to be soaked in liquid Helium to reduce
their temperature to a value close to absolute zero
-STATIC MAGNETIC FIELD COILS

15. 1-Gradient coils are used to produce deliberate
variations in the main Magnetic field
2-There are usually three sets of gradient coils,
one for each direction
3-The variation in the Magnetic field permits
localization of image slices as well as
phase encoding and frequency encoding
4-The set of gradient coils for the Z axis are
Helmholtz pairs, and for the X and Y
axis are paired saddle coils
-GRADIENT COILS

16. -MRI Scanner Gradient Magnets

17. 1-RF coils act as transmitter and receiver
2-RF coils are the “ANTENNA” of the MRI
system
3-That transmit the RF signal and receives
the return signal
4-They are simply a loop of wires either
circular or rectangular
5-Helmholtz pair coils consist of two circular
coils parallel to each other. They are used
as the Z gradient coils in MRI Scanners
6-Paired saddle coils are also used for the X
and Y gradient coils
-RADIO FREQUENCY COIL

18. 1-No ionizing Radiation
2-Variable thickness in any plane
3-Better contrast resolution
4-Many details are achieved without I/V
contrast
-ADVANTAGES OF MRI

19. 1-Very Expensive
2-Dangerous for patients with
metallic devices placed within
the body
3-Difficult to be performed on
daustrophobic patients
4-Movement during scanning may
cause blurry images
5-RF transmitters can cause severe
burns if mis handled
-DISADVANTAGES OF MRI

20. SHAPES OF MRI
MACHINE

21. -a-CLOSED MRI MACHINE

22. -b-OPEN MRI MACHINE

23. -UPRIGHT MRI

24. 1-Since the earlier 1990’s FMRI had come
2-FMRI is based on the same technology as
MRI
3-FMRI looks at blood flow
4-It is a technique for measuring Brain activity
5-It works by detecting the charges in the
blood oxygenation and flow that occur in
response to neural activity
-FUNCTIONAL MRI

25. 1-MRI
2-Views anatomical
structure
3-Focuses on protons in
Hydrogen Nuclei
4-High Spatial resolution
5-Utilized for
Experimental purposes
-DIFFERENCE BETWEEN
MRI and FMRI
1-FMRI
2-Views Metallic
function
3-Calculates Oxygen
levels
4-Long distance
Resolution
5-Utilized for
Diagnostic purpose

26. -MRI Scan
-DIFFERENCE BETWEEN MRI and FMRI
-FMRI Scan

27. -Comparison between
X Ray system=CT System=and MRI System