Thank you for pointing that out! I took another look and was able to get the following;

 

TotalGray (from the aseg.stats) = 751765.612392

 

298534.487540 (lhCortex) + 287682.124852 (rhCortex) +  58860.000000 (SubCortGray) + 52358.1 (L_cerebellum-cortex) + 52661.8 (R_cerebellum-cortex) = 750096.512392

 

There is still a difference of 1669.1. What could account for the difference?

 

Best,

Da-Yea

 

 

 

        External Email - Use Caution        

Hello,

 

I had a question regarding the aseg.stats and was hoping to get some help.

 

1.       How is the TotalGray calculated? On the wiki page it mentioned that it is the sum of lhCortex + rhCortex + SubCortGray + CerebellumGM. I tried calculating this based on the formula but got different results.

a.       TotalGray (from the aseg.stats) = 751765.612392

b.      298534.487540 (lhCortex) + 287682.124852 (rhCortex) +  58860.000000 (SubCortGray) + 49.3682 (L_cerebellum-cortex) + 50.1232 (R_cerebellum-cortex) = 645176.103792

Check your value for cerebellum cortex. It should be more like 60,000 mm3. You probably are looking at the mean intensity.

 

2.       We have subjects that were processed in v4.0.4 and v6.0.0. Since the TotalGray measure did not exist in the v.4.0.4, what could we use to calculate the volume?

How about the above formula?

 

Thank you so much in advance for your help!

 

Best,

Da-Yea

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