Re: [vmtk-users] (no subject)

[Luca A. <luc...@or...>]

Hello Yong,
 thanks for the informative message (I particularly liked the metal wire!).

Indeed the centerlines filter doesn't catch loops, which is usually ok for 
arterial trees, but it can be limiting in other situations such as yours.
The reason is that the algorithm searches for some sort of shortest path
from the inlet to the outlet, thus is will only choose one of the two arms
of the loop.

There are a couple of things you can do:

1) This is a hack:
  a) generate one centerline and save it to a file
  b) use vmtksurfaceclipper to make a cut in the branch in which the centerline 
      was generated
  c) run vmtkcenterlines again; it will extract the other branch (since the former
      is not continuous due to the cut); save it to another file
  d) use vmtksurfaceappend to have the two centerlines in one dataset, if you
     need this

2) use vmtknetworkextractor; make sure the surface has at least one opening
  and run the script; this algorithm is less accurate in tracing the centerline,
  although it might be enough for your needs; however, it handles loops correclty

Hope this helps


Luca


On Feb 22, 2013, at 9:54 AM, Leong Yong Shin wrote:

> Hello everyone, I am an user of VMTK on 3D Slicer. I am working on a project that requires me to trace the centerline of a liver fibrosis structure. I have developed phantoms (that mimic the fibrosis structure) and imaged it using X-ray CT. My desired outcome is the centerline tracing of the loop, shown in the figure below:
> 
> <image.png>
> 
> However, I have only been able to trace a single branch of the loop, shown below:
> 
> <image.png>
> 
> I need advice on how to perform centerline tracing on both branches using one start point and one target point. Note: both centerlines should intersect each other at the opposite end of the loop.  
> 
> Any help is greatly appreciated. Thanks.
> 
> -- 
> Take Care!
> Leong Yong Shin
> School of Chemical & Biomedical Engineering
> m: +6596809912
> e: leo...@gm...
> 
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