2017 Imaging for Physicists Coursebook

Gradients

B 

0  

• Recall that the resonant frequency is proportional to field strength

0

dB

G x



0

dx

• Magnetic gradient changes B 0 strength over distance • In MRI a linear gradient changes the resonant frequency in a given direction field

dB

G y



0

dy

dB

G z



) x xG B  





(

0

dz

0