COMPONENTS OF MRI

SIR SYED UNIVERSITY OF ENGINEERING AND TECHNOLOGY

SYED HAMMAD AKHTER

2012-BM-071

PRESENTED TO

ENGR. FAHAD AKBER

ComponentsMAGNET

SSuper 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

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)

RADIO FREQUENCY SYSTEMSignals 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)

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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 SignalProvide data from which image is reconstructedResulting image is display of RF signal

RF TRANSMITTER

RF RECIEVER

MRI IMAGES