Can I predefine the size of a rectangular ROI in MRView? And another question about spherical ROIs

Hello MRtrixers,

I have a couple of (hopefully) simple questions about ROIs.

Is it possible to predefine the size of a rectangular ROI created using the ROI editor in MRView, making it easier to reproduce the exact same size and dimensions multiple times with different subjects.

My second question is, when I use the seed_sphere option in tckgen, is it possible to visualise the seeding sphere that I produced in MRview (or any other viewer for that matter)?

I hope my questions make sense! :sweat_smile:


I’m not 100% sure what you’re asking here…? Can you elaborate on how you’d see working? Are you trying to create a rectangular ROI and place it in different or equivalent locations across subjects…?

Unfortunately not… This has been on the todo list for a very long time. If anyone want to get into a bit of OpenGL / C++ / Qt programming, please get in touch!

Yes, that’s exactly what I’m trying to do! Sorry for the awkward wording :sweat_smile: Is that somehow possible??

Ok. As stated in the other thread, this is obviously not a priority, I’m sure you have a lot more pressing matters on your plate. Thanks for the response anyway!


It’s still not 100% clear exactly what you’re trying to achieve, but I’ll throw in a couple of possibilities:

  • If you register each subject to a template, and define your rectangular ROI in template space, you could then transform that back to each individual subject. Whether or not this is appropriate depends on the particulars of your experiment that are still slightly unclear.

  • While the mredit command does not currently have the capability to draw rectangular cuboids, this would not be a very difficult capability to implement. It would however have the constraint that the shape would be axis-aligned, rather than being an XYZ rectangular cuboid relative to the scanner axes re-sampled onto a particular voxel grid.