Hello everyone,

I would like some litterature and info on a problem I have.

We are using a BOLD-ASL sequence where we can extract BOLD signal and CBF.

I would like to clean ASL (CBF) data using T2* of the tagging.

As far as I understand, it should be in an equation like such :

where A is T2* at this voxel, for this specific TR (even though it has been surround subtracted).

Now my question : Is the T2* of my exp function describing ASL signal decay the same as in the simultaneous BOLD signal ?

What is the different in the BOLD equation between tagged and control images (ASL alternates one tagged TR with control/unlabelled) ?

Would it be a sum of a BOLD exponential with ASL tag equation with identical T2*?

If the blood has been tagged with a delay prior to the imaging (1.5s) is it the same T2* ?

Thanks for any help on this mathematical question.

I hope you can clarify some points.