2017_Imaging for Physicits_Florence

Previous Page

Next Page

Page Background

B0 mapping

• Air/tissue interfaces problematic

• Dynamic & HO shimming

• May be measured/corrected:

• Image at two different TEs

• Reconstruct phase difference

• Bhagwandien measured -5 to

+6ppm i.e. nearly twice WFS

γΔTE

Δφ

ΔB

0

=

Maximum 34 Hz (0.3 ppm)

Maximum

203 Hz (1.6

ppm @ 3T)

Magnitude

Difference

Phase (TE1) Phase (TE2)