open-discussion > Shim box issue
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Jul 31, 2023  09:07 PM | sognoe
Shim box issue

Hello, I'm doing multi-modal shooting with 3T Simens.

As far as I know, the contents of the picture below are known as shim boxes.

Could it be a problem for functional MRI analysis that the difference from rotation degree, R>>L, A>>P, F>>H in "adjust volume" of each participant?

T1

DTI

Below is an example, and the values are slightly different for each participant.

1. T1 Protocol
- Same point: The TR, TE, FOV, and FA of the participants are all the same.
- Differences: R>>L, A>>P, F>>H
example)
'a1 participant' was taken as R>>L = 350, A>>P = 298, F>>H = 303, and 'a2, a3 participant' was taken as R>>L = 350, A>>P = 298, F>>H = 350 .

2. DTI Protocol
- Same point: The TR, TE, FOV, and FA of the participants are all the same.
- Differences: R>>L, A>>P, F>>H, rotation
'b1 participant' was taken as R>>L = 192, A>>P = 192, F>>H = 144, rotation=180 deg, and 'b2 participant' was R>>L = 220, A>>P = 220, F>>H = 149, rotation= 0 deg, participant 'b3, b4' is taken as R>>L = 350, A>>P = 298, F>>H = 350 , rotation=0 deg .