Dear Will and Zoltan,
Thank you guys for providing excellent explanations. I appreciate it
veru much. Could I ask you a second question? ;-)
As you can see, I am carrying out a clinical examination, in which I
compare each patient value with normal values derived from 27 controls
on MRI after normalization of all patients and control images. In the
previous mail, I wrote that I did not use "grand mean scaling",
"Threshold masking", "threshold", "Implicit mask", "explicitly mask",
"Global calculation", and "non-sphericity correction." However, I
realized that this was a first-level analysis. Therefore, I thought I
should have used some of them, and I tried to use them in GUI of SPM2
as followings;
1. grand mean scaling ---> scaling of overall grand mean
2. scale overall grand mean to ---> 50
3. Threshold masking ---> relative
4. threshold (relative to global) ---> 0.8
5. Implicit mask (ignore zero's)? ---> no
6. explicitly mask images? ---> no
7. Global calculation ---> mean voxel value (within per image
fullmean/8 mask)
8. non-sphericity correction? ---> no
Then, I obtained very similar results to those when I said no to all
options described above. I am wondering which is the correct way and
which values are correct if I should use grand mean scaling and
masking etc. I would appreciate any help very much in advance.
--
Kohkichi Hosoda M.D.
Department of Neurosurgery,
Hyogo Emergency Medical Center/Kobe Red Cross Hospital,
1-3-1 Wakinohama-Kaigan-Dori, Chuo-ku, Kobe, 651-0073, JAPAN
Telephone 078-241-3131
Fax 078-241-2772
e-mail address : [log in to unmask]
