Hello,
I have data from a modality that can't readily be overlaid onto an anatomical image. The data is from magnetic resonance spectroscopy (MRS), and is basically a 10mm thick axial/oblique slice. I have the header file for the MRS data and it contains RAS coordinates for the following points within the slice:

...(R,A,S) center coordinate of image: (1.66468, 7.78435, 18.8169)
...(R,A,S) normal coordinate: (-0.0263348, -0.0221738, 0.999407)
...(R,A,S) coordinate of top left hand corner: (151.527, 157.748, 26.091)
...(R,A,S) coordinate of top right hand corner: (-148.372, 157.748, 18.1897)
...(R,A,S) coordinate of bottom right hand corner: (-148.198, -142.179, 11.5428)

Given these points, I'd like to create a simple 3-D rectangular/box mask that is shaped exactly like the MRS slice, so I can overlay it on the anatomical image (in native space). If the slice were exactly on the axial plane, it would be relatively easy to create the mask using 3dcalc or 3dUndump, but I don't really know where to start since its slightly oblique. All MRS slices were prescribed parallel to the line between the genu and splenium of the corpus callosum, which was slightly tilted in most cases.

Thanks for any pointers and advice,
Mike