Q2ec-FM004916
6.4 Imaging of diffusion weighted images (DWI) (reservation):for Gating
Before you start DWI, you need to perform volume shimming to improve the uniformity of the static magnetic field.
If measurement is performed under any of the following circumstances from 1) 2) 3), after volume shimming, perform the volume shimming
again because the measurement will have invalidated the result of volume shimming:
1) Measurement performed after a change of patient Orientation by using Patient Registration window,
2) Measurement performed after a change of receiving coil,
3) Measurement performed with Prescan of main scan set to ON
1
Select Shim AX.
2
Set shim slice lines not to include the
paranasal sinus(air).
When performing volume shimming,
you cannot change the angle of the
slice lines or move the slice lines R-L
and A-P directions. The range of H-F
direction movement of the slice lines is
also limited.
The results of volume shimming can be
viewed at WW/WL＝500/10.
If the result is defective, change the
plane and then retry.
Examples of defective results:
- A portion has excessively high
brightness.
- There are large differences in
brightness in the image.
Click
3
Chapter 6 Imaging
NOTICE
Check the position of the slice lines.
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2
3
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