Hi All
I am trying to co-register my Mean EPI image to structural scan prior to segmentation and normalistation and I have a query regarding the output. Probably best if I try and explain my query with one subject example. Any advice much appreciated.
So far I have reoriented the EPI scans to the AC. Then carried out unwarp and realign reslicing all images & mean image. Now I am trying to coregister the mean EPI to our stuctural scan. Initially I did not reorient the T1 image but I get a .ps out put which looks like below:
X1= 0.292*X +0.007*Y+ 0.004*Z -6.128
Y1= 0.007*X +0.292*Y+ 0.021*Z -0.750
Z1= 0.004*X +0.204*Y+ 0.331*Z -22.222
and the cross hair on the image is not at the AC. When I do check reg the 2 images are aligned. Does the -22.222 mean an error on the Z axis?
I then thought I would reorient the structural scan to see if this improved the situation but it has made virtually no difference to any of the values and once again the cross hair falls in a different location for all subjects.
My query is mainly is the -22.22 and -6.128 values above errors on those axis and if so will they affect strongly my results as I progress through the preprocessing and on to stat analysis. If so do you have any advice on how I could reduce them?
Many Thanks Susannah
