Dear all,
I have a bunch of DTI-datasets from patients who have undergone functional
hemispherectomy. Since I want to run voxelwise analyses, I need to
normalize these highly deformed brains. It seems that the normalization of
T1 is affected by a field bias (i.e. occipital hyperintensities and frontal
hypointensities). I, therefore, want to correct the field bias. There are
four quesions I have:
question1. When I generate a bias field by means of FAST, it turns out to
be affected by the low signal in the lesioned hemisphere. Now I wonder
whether I can run FAST with the lesion masked out?
question2. Is it possible to create some kind of average field-map out of
several unlesioned-brains (who have been scanned with the same sequence and
the same scanner) bias-fields (generated by means of FAST) and apply this
on the lesioned ones?
question3. Should I use segmentation with FAST to remove the CSF before
creating the bias field?
question4. Is there any advantage in using mfast (e.g. with a T2) while
creating this bias-field (if the bias field is only noticeable on the T1)?
Any help on this is highly appreciated.
Thanks in advance!
Best,
Theodor.
Theodor RĂ¼ber, MD
..............................................................
Department of Epileptology
University Hospital Bonn
..............................................................
Sigmund-Freud-Str. 25
53127 Bonn
Germany
..............................................................
[log in to unmask]
www.epileptologie-bonn.de
CASA HOGAR
..............................................................
Collegium Albertinum
Adenauerallee 19
53111 Bonn
Germany
..............................................................
Spendenkonto: casa hogar
IBAN: DE19 3706 0193 1000 1000 44
BIC: GENODED1PAX
..............................................................
[log in to unmask]
www.casa-hogar.de
|