[Mristudio-users] Fwd: questions about ROI's

[Xin Li]

Hello Darren,

1)It may be caused by integer rounding. I am looking into this. 

2) ROIEditor displays the contour of a ROI object stored in memory. In your figure, it includes those brown voxels. I am looking into this and try to find a way to let ROIEditor come up with a more symmetric ROI.

3) After you add a ROI to an object, you may use "undo" if it is the last step.

5) "undo" only works for the last step if it is the "add", "subtract", "and" or "replace" operation.


Regards,

Xin








----- Original Message -----
From: Darren Gitelman <d-gitelman at northwestern.edu>
Date: Monday, July 5, 2010 1:26 pm
Subject: [Mristudio-users] Fwd: questions about ROI's
To: mristudio-users <mristudio-users at mristudio.org>


> I have several questions about ROIs
>  
>  1) In both DTIstudio and ROIeditor ROIs of fixed size are placed with
>  reference to the lower right quadrant of the crosshairs. Is there a
>  reason for this or could the ROI be placed centered on the crosshairs?
>  
>  2) I would like to know how dtistudio and roieditor calculate the
>  values of ROIs. Please see attached picture. On the left, is a 4 voxel
>  diameter circular ROI overlaid on a grid. This is what the ROI looks
>  like when I first draw it in either DTIstudio or ROIeditor. On top of
>  this is a set of brown voxels, which is what the ROI looks like in
>  ROIeditor when I add it to an object. On the right is the 4 voxel
>  circular ROI on top of a 4 voxel square. How do DTIstudio and
>  ROIeditor get the value of an ROI?
>     - Does it perform a weighted average of voxels in the circle
>  (orange part of circle)?
>     - Does it include only the voxels that show up in the brown object.?
>     - Does it include any voxels that touch the circle (i.e., blue square)?
>  
>  Do DTIstudio and ROIeditor do the same thing when determining the
>  value of ROI's?
>  
>  3) Is there any way to un-associate an ROI from an object so that it
>  can be moved around again or once it's added to an object that's it?
>  
>  4) Is there any way to save ROIs in DTIstudio?
>  
>  5) I've noticed in ROIeditor that undo doesn't always undo the last operation.
>  
>  Thanks,
>  Darren 
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