Thanks Sita for your anwser, but, i'm sure that i'm using the correct tool, the thing is that i can erase the wrong voxels, but, when i erase them, they get coloured with a diferent contrast, i have tried to change the volume tool configuration and still appears with different contrast (a grey colour)

thanks Silvia

2009/2/19 Sita Kakunoori sita@nmr.mgh.harvard.edu:

Make sure you are selecting the 'Edit segmentation tool' on the tkmedit tools window. You can also press the 'g' key to select the tool.

Sita.

On Thu, 19 Feb 2009, Silvia biopanda wrote:

...

Hi, we are making changes in the aseg.mgz and we need to know how to erase a wrong pixels. we read in the tutorial that the button three erases, but it doesn't work.how can we do? cheers, SK _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer

I will edit the wiki page - I believe it is wrong. You cannot erase a segmentation by using the 3rd mouse button. In order to erase, you actually have to re-draw what the underlying segmentation was originally.

If you are working on the aseg.mgz and plan to save your edits as aseg.mgz, to "erase" something you adding in error you right click on the Edit Segmentation button and the Segmentation Brush Info window will pop up. From the list of structures, choose the one that the area you edited was originally. For example, if you were adding thalamus on top of Left Cerebral White Matter and what to delete the thalamus label, choose Left Cerebral White Matter and use the 2nd mouse button to draw over the thalamus voxels you want to remove.

If you are creating a segmentation and not saving it as aseg.mgz, you probably want to choose "0 Unknown" from the Segmentation Brush Info list to "erase" segmentation you have added. Allison