Hello, Everyone,
Sorry take your time! I have one problem due to negative signal intensity after SPM motion correction.
I am doing t2* map of brain. And my first step is pre-processing of raw data (signal intensity). After SPM motion correction (realignment and reslice), I found negative signal intensity generated. And these negative signal intensity will cause complex t2* values, but t2* values should be at least real. Thus my t2* map will contain a lot of artifacts.
So I wish to ask how to deal with these negative signal intensity? I do not know if I can introduce an offset to make negative values become positive, IF I can, how big the offset should I use?
Thank you!
Shangwenyan Gong
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