[MINC-users] get_meansd_voi --- problems with PET volumes

[EJ Nikelski]

Hi,

   I'm trying to extract VOI mean and sd using get_meansd_voi. When I
try it using ...

>get_meansd_voi pet.mnc 0 0 0 1 0

... which should get me the value at Talairach (0,0,0), instead, I get

>n/a n/a 0

   Interestingly, if I try to use a larger roi radius, I get ...

[~] 83 >get_meansd_voi pet.mnc 0 0 0 1 3
ncvarget: ncid 3: Index exceeds dimension bound
miicv_get: MINC package entry point
ncvarget: ncid 3: Index exceeds dimension bound
miicv_get: MINC package entry point
0.000 0.000 3

   Now, if I try this with the average 305 MRI T1, I get no problems.
Perhaps the problem is related to the volume data type? The PET volume
I'm using is the usual ...

[~] 84 >mincinfo pet.mnc
file: pet.mnc
image: signed__ short -32000 to 32000
image dimensions: zspace yspace xspace
    dimension name         length         step        start
    --------------         ------         ----        -----
    zspace                     63       -2.425      -427.96
    yspace                    128        2.025     -128.588
    xspace                    128        2.025     -128.588


   Now, I'm certain this has worked before ... and on the same PET
volumes. What am I missing?


Thanks,

-Jim


-- 
E. James Nikelski, Ph.D.
Postdoctoral Research Fellow
Bloomfield Centre for Research in Aging
Lady Davis Institute for Medical Research
Sir Mortimer B. Davis - Jewish General Hospital
McGill University
Tel: (514) 340-8222 x 2298
Fax: (514) 340-8295