Trying to add different stenosis degrees to model

[Jack Tattersall]

Hello all,

I have the following question: I have MRI images from AV graft patients, and with SimVascular I have created a model of the venous anastomosis + part of the vein and part of the graft. The model can be seen in the attachment. Now I am longitudinally following these patients up with ultrasound scans and they are indeed getting stenoses couple of cm behind the anastomosis. I want to be able to implement this is my model.
So, for example, I can see that the diameter at a location now has reduced from e.g. 4mm to 2mm. I want to locally change the existing model so that it is narrower at this point, if that makes sense. I was wondering if there is a handy way to do this in SimVascular, or that I have to export centerlines or something and try it via different software?

Thanks in advance!
Cheers,
Jack

[David Parker]

Hi Jack,

You can interactively change a contour radius from the SV 2D Segmentation tool. When you select a contour its center and radius is displayed as two green rectangles. You can modify them using the left mouse button. After you modify the radius click on the contour name again and the new contour area is displayed at the bottom of the SV window. You can modify the radius to match the area of the stenosis. I've attached an image describing how to do that.

You can also replace your contours with a Circle. You can then manually set the circle radius by right clicking on the Circle button.

Cheers,
Dave

[Erica Schwarz]

Hi Jack,

In addition to the solution Dave mentioned below, I have also made a python script that will programmatically alter contours in a segmentation file to create stenosis segmentation files. The scripts are attached below, check out stenosisDriver.py for usage- basically you input what segmentation you are trying to stenosis and which contour in that file specifically you want to change it it will output segmentation files with that particular contour scaled to reflect the different stenosis areas you specify. If you run that and make sure the resulting .ctgr files are in the project segmentation folder, the next time you open the project the should be in the segmentation tree and you can model and mesh them as desired.

stenosis.zip

(1.59 KiB) Downloaded 30 times

[Jack Tattersall]

Thanks both, Erica I will have a look at your script this afternoon.
I know of that method david however, only with a circle would this work due to the fact that I want to be precise with my diameter so interactively sliding and changing will not really work, since I won't know which diamtere it is. However I will also try replacing by circles.

Thanks again!
Cheers,
Jack

[Jack Tattersall]

Thanks Erica,
script was what I was looking for!