[MINC-users] Time frame start values

[Alex Zijdenbos]

Hello all,

I've running into an issue I don't know what to do with (yet). How are (or
should) start values be interpreted in a MINC time-dimension?

For spatial dimensions, the voxel positions are in the center of the voxel;
but in converting dynamic PET data from various scanners, we are seeing
what looks like variations between scanners in terms of whether the start
is center-frame, or start-of-frame.

We also sometimes end up with negative time steps out of dcm2mnc, which
calls into question whether (a) that should ever happen; and (b) how for
example mincreshape behaves when re-ordering that dimension. My assumption
is that mincreshape will interpret the start to be center-frame, and that
therefore changing the sign of the time-step might end up with a wrong
start value.

If anybody has thoughts about or experience with these issues, please share
:-)

Thanks,

-- A