Segmentation Question ; automatic segmentation difficulties.

Provides a system for patient-specific cardiovascular modeling and simulation.
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Jack Tattersall
Posts: 12
Joined: Thu Nov 21, 2019 6:23 am

Segmentation Question ; automatic segmentation difficulties.

Post by Jack Tattersall » Wed Jan 08, 2020 4:27 am

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
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SimV_segmentation.PNG
bottom left hand corner the faulty contours are visible
SimV_segmentation.PNG (132.01 KiB) Viewed 259 times

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David Parker
Posts: 1747
Joined: Tue Aug 23, 2005 2:43 pm

Re: Segmentation Question ; automatic segmentation difficulties.

Post by David Parker » Thu Jan 09, 2020 12:39 pm

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
Attachments
Screen Shot 2020-01-09 at 11.36.09 AM.png
Screen Shot 2020-01-09 at 11.36.09 AM.png (106.18 KiB) Viewed 239 times

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