[MINC-users] mincresample and minctracc question

[EJ Nikelski]

Hi All,

    I'm trying to align a PET volume to it's anatomy, and am running
into some problems (and could use some help).  I just have a couple
of questions ...

(1) do I need to resample my anatomical volume to match that of the
functional volume prior to calling minctracc?

(2) when I try to resample the native MRI to the functional, I usually
get an empty volume out. I suspect that this is related to the
difference in z-start values, but am unsure how to proceed.  The 2
input volumes look like this ...

** MRI **
file: lestat_t1_native.mnc
image: signed__ short 0 to 4095
image dimensions: xspace zspace yspace
    dimension name         length         step        start
    --------------         ------         ----        -----
    xspace                    176            1     -85.4759
    zspace                    256           -1      113.831
    yspace                    224           -1      144.386


** PET **
file: pibXmean.mnc
image: unsigned byte 0 to 255
image dimensions: zspace yspace xspace
    dimension name         length         step        start
    --------------         ------         ----        -----
    zspace                     63       -2.425       -452.7
    yspace                    128      2.05941     -130.772
    xspace                    128      2.05941     -130.772


The mincresample command and the resulting volume looks this ...

>>mincresample -verbose -clobber -like pibXmean.mnc lestat_t1_native.mnc lestat_t1_native_rsl.mnc

** resampled empty T1 volume --
file: lestat_t1_native_rsl.mnc
image: signed__ short 0 to 4095
image dimensions: zspace yspace xspace
    dimension name         length         step        start
    --------------         ------         ----        -----
    zspace                     63       -2.425       -452.7
    yspace                    128      2.05941     -130.772
    xspace                    128      2.05941     -130.772



(3) does minctracc want both volumes to share the same data type (e.g.
byte) or does this not matter?

(4) should I blur the native T1 prior to fitting? ... or does minctrac
deal with this?


Thanks,


-Jim