Dear everyone,
I use SPM'99 to segment 3-d gradient-echo datasets.(TR
= 19ms, TE = 4,4 ms, flip = 8, FOV = 23 cm, thickness
3mm, gap = 0, slices = 60). I get good results, when I
use the PD-weigthed template. Usually the segmentation
is almost perfect. Sometimes (on some heads) the
segmented areas are much too small, especialy in upper
regions. I tried quite a lot to find the reason for
that but I can't find a systematic. I have a couple of
ideas: Does the ratio between FOV and head size have
any influence on the segmentation ? How does the
position of the head (i.e. rigth-left) influence the
quality of the segmentation ? The results are better
if the first 5 slices(head first) of the dataset are
above the skull, but this is difficult to implement
into clinical routine.
Does anybody have an idea ?
regards
Gregor Jost
Heidelberg medical school
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