[MINC-users] dcm2mnc and (ir)regular spacing (again)

[Alex Zijdenbos]

Hello all,

I am staring at another dimension step/spacing issue (from a 4D PET
volume). In a MINC volume produced by dcm2mnc, I have:

$ mincheader test.mnc | grep time
        time = 4 ;
        double time(time) ;
                time:varid = "MINC standard variable" ;
                time:vartype = "dimension____" ;
                time:version = "MINC Version    1.0" ;
                time:spacing = "irregular" ;
                time:alignment = "start_" ;
                time:units = "s" ;
                time:step = 225. ;
                time:start = 197.88 ;
        double time-width(time) ;
                time-width:varid = "MINC standard variable" ;
                time-width:vartype = "dim-width____" ;
                time-width:version = "MINC Version    1.0" ;
                time-width:spacing = "irregular" ;
                time-width:filtertype = "square____" ;
        short image(time, zspace, yspace, xspace) ;
        double image-min(time, zspace) ;
        double image-max(time, zspace) ;
                study:start_time = "142857" ;
                acquisition:start_time = "20110114 142857" ;
 time = 197.88, 497.88, 797.88, 1097.88 ;
 time-width = 299.88, 299.88, 299.88, 299.88 ;

So time:spacing is listed as "irregular"; and looking at the time- and
time-width vars the frame times are 300s apart (give or take).
However, the time:step attribute is 225, not 300.

Is this basically broken MINC? I assume the time:step attribute
somehow is generated from some DICOM field, but is basically wrong?
Question perhaps is: when there is conflicting step information, which
should take precedence?

Thanks,

-- Alex