Dear All,
During my data processing, I encountered some problems.
I used VBM to analyse MRI scans of 111 subjects, which were divided
into three groups: 26 healthy individuals, 54 individuals with left-TLE and
31 individuals with right-TLE.
£Æ£é£ò£ó£ô of all£¬ £É £òeoriented the images to make the segmentation
more accurate. After segmentation, I used the DARTEL tool for VBM. I
created the template with the 26 healthy individuals, and then I warped
every TLE individual to the existing template. In addition, I used DARTEL to
spatialy normalize all the images to £Í£Î£É space. At last, I smoothed the
processed images with a 8mm Gaussian smoothing kernels.
In the statistical analysis, I tried to find the differences
between the left-TLE individuals and healthy ones, or the right-TLE
individuals and healthy ones. Here, I only take the former for example. I
used the two-sample t-test, one group is the individuals with left-TLE, and
the other group is the healthy individuals. I set the contrast as [1 0], and
the p value as 0.05. Then, I got the result as seen in the enclosure.
I find the result a little weird. From the upper picture, I thought
there were lots of volumns superior to the threshold. In contrast, I saw
only a few volumns from a whole brain as shown in the table below. What's
more, when I set the contrst as [-1 0] , [1 -1] or other values, I cannot
find any volumns superior to the threshold. I cannot explain why and I
appreciate if you can help me!
With regards!
Wenjing.Li
