Segmentation Question ; automatic segmentation difficulties.

[Jack Tattersall]

Hello,

Ik trying to segmentate an Arterial Venous Graft and the corresponding vein and artery it's connected to. Whilst testing some other images, the LevelSet option worked for me and I was able to automatically let Simvascular sementate my images through the planned path. Now, however it keeps selecting a faulty contour at the bottom left had corner, every slice the same. as can be seen in the attached image. During the aquisition of the images, it was chosen that all the vessels appear black (or else the venous part wouldn't be visible due to high flow differences in vein and the graft).
Maybe this is the cause that the level set does not work, or maybe because I have the wrong parameters selected.
Machine learning and Threshold also did not work, but I had my hopes on levelSet because that worked well for me on another image.
Can anyone possibly identify the problem of the levelset not working or what to alter in order to have SimVascular automatically contour and segmentate my image.


Thanks in advance,
Jack Tattersall

[David Parker]

Hi Jack,

The levelset segmentation method does not work on your images because it uses the image gradient to propagate the levelset curve, and there is no image gradient for these black vessels. You will need to use a manual method.

Or you could perform an image inversion using the SV Image processing tool selected from the SV toolbar (the paint brush icon).

Cheers,
Dave