basic and brief but informative knowledge about how MRI works and what are its components ... easy to understand as well as presenting during lectures and in classes . share it

1. COMPONENTS OF MRI
SIR SYED UNIVERSITY OF ENGINEERING AND
TECHNOLOGY
SYED HAMMAD
AKHTER
2012-BM-071
PRESENTED TO
ENGR. FAHAD
AKBER

2. Component
sMAGNET
S
Super conducting magnet
•Very high voltages are used
•Wire is winded on coil & electrically
applied to the ends
•More voltage greater the field
Permanent magnet
•Heavy weight
•Full of strength
•Low cost
•Internal core is made of it that generate
mag field all the time
Resistive magnet
•Internal x-axis is controlled by resistive
magnet
•Portion of imaging is controlled

3. GRADIENT COIL
 Have a magnetic field that changes
temporally and able to variate its field .
 Contained with in magnetic assembly
 Magnetic field produced must be
distorted or altered with gradient coil
 Imaging magnet contains three separate
set of gradient coils produced in 3
directions (x,y,z directions)
SHIELDING
 Magnetic field shielding
(shield by conducting material like iron)
(Improves homogeneity by protecting from interference)
 RF shielding
(enclosing in material like copper to block external RF
interference)
COMPUTER
 Data acquisition control
(acquisition of RF signal from patient body . Sequence
of RF pulse is transmitted to the body)
 Image reconstruction
(computer use collected data during acquisition
process to create or construct image by fourier
transform)
 Image storage
(image are stored in the computer for future viewing)

4. RADIO FREQUENCY
SYSTEMSignals are used to transmit the image from the patients
body in MRI process.
RF energy is used is a form of non ionizing radiation
RF COILS
 These are located with in Magnet
 Function as antennae for both transmitting and
receiving signals from tissues.
 Three basic types of RF coils used according
different anatomical regions.
√ Head = for head region
√ Body = for thorax and abdominal region
√ Surface = for small regions (limbs)
:
 Generates RF energy in the form of RF pulses
 Applied to coil and transmitted to patient’s body
 Absorbed by the tissues
 Short time after RF pulse transmission resonating
tissue will respond by returning Signal
Provide data from which image is reconstructed
Resulting image is display of RF signal
RF
TRANSMITTER
RF RECIEVER

5. MRI IMAGES