Dear All,
I think I found the source of the discrepancy. Currently I am using FSL v3.3.
avwstats -v (no ++) returns a *slightly* different volume value than avwstats++
fslstats (v4.0.1) returns the same volume value as avwstats++
When I use avwstats (no ++), i get nearly identical numbers as to what is in the *.sienax file:
% avwstats 20071129_13_1_stdmaskbrain_pve_0 -m -v
0.050212 7864320 6308232.703233
% avwstats 20071129_13_1_stdmaskbrain_pve_1 -m -v
0.081955 7864320 6308232.703233
% avwstats 20071129_13_1_stdmaskbrain_pve_2 -m -v
0.060953 7864320 6308232.703233
>> csf = 0.050212 * 6308232.703233;
>> grey = 0.081955 * 6308232.703233;
>> white = 0.060953 * 6308232.703233;
>> bpf = ( grey + white ) / ( grey + white + csf );
>> fprintf( 'csf = %.1f grey = %.1f white = %.1f bpf=%.6f \n', csf, grey, white, bpf );
csf = 316749.0 grey = 516991.2 white = 384505.7 bpf=0.739996
From *.sienax file:
Class: CSF tissue 1 tissue 2 brain percentage
Volumes: 316748.7 516990.9 384503.5 0.739996
Results from avwstats++ are below, but bottom line:
csf = 316824.7 grey = 516909.2 white = 384486.8 bpf = 0.7399
I believe that the results generated from sienax/FSL v3.3 would be slightly different from
sienax/FSL v4.0.1 due to the use of avwstats v fslstats, respectively.
Is this something you see, too?
Thanks,
- BettyAnn
On Wed, 2 Jan 2008 20:11:23 +0000, Bettyann Chodkowski
<[log in to unmask]> wrote:
>Mark,
>
>Ah, thanks. This helps a great deal.
>
>The values I calculate for the tissue classifications are still not exactly the same as what I see
>reported in the *.sienax file. The final brain percentage value does match, however. Might you
>see something I am doing wrong? i used fsl v3.3 when running sienax but fsl v4.0.1 for fslstats
>(which gives the same values as avwstats++ v3.3).
>
>% fslstats 20071129_13_1_stdmaskbrain_pve_0 -m -v
>0.050224 7864320 6308232.500000
>% fslstats 20071129_13_1_stdmaskbrain_pve_1 -m -v
>0.081942 7864320 6308232.500000
>% fslstats 20071129_13_1_stdmaskbrain_pve_2 -m -v
>0.060950 7864320 6308232.500000
>
>in matlab:
>>> csf = 0.050224 * 6308232.500000;
>>> grey = 0.081942 * 6308232.500000;
>>> white = 0.060950 * 6308232.500000;
>>> bpf = ( grey + white ) / ( grey + white + csf )
>bpf = 0.7399
>>> fprintf( 'csf = %.1f grey = %.1f white = %.1f \n', csf, grey, white );
>csf = 316824.7 grey = 516909.2 white = 384486.8
>
>The tissue volumes in my *.sienax file are:
>
>Class: CSF tissue 1 tissue 2 brain percentage
>Volumes: 316748.7 516990.9 384503.5 0.739996
>
>Also, in the snippet of code from the sienax script where the volumes are computed, are you
>dividing the result by 1 in the dc calculator? if so, why?
>
>Thank you for your help,
>- BettyAnn
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