Tie a sphere transform to the ROI of a FiberBundle managed by SlicerDMRI

SlicerDMRITransformROIFiberBundle.py

import numpy as np    

# Get the transform of the sphere
t = slicer.mrmlScene.GetNodesByName("center").GetItemAsObject(0)
mat = vtk.vtkMatrix4x4()
t.GetMatrixTransformToParent(mat)

# Get the region extracting the ROI from the fibers
fbn = slicer.mrmlScene.GetNodesByClass("vtkMRMLFiberBundleNode").GetItemAsObject(0)
efr = fbn.GetExtractFromROI()

# Create a sphere implicit function and enable masking
sphereFunc = vtk.vtkSphere()
sphereFunc.SetRadius(5.0)
sphereFunc.SetCenter([mat.GetElement(0, 3), mat.GetElement(1, 3), mat.GetElement(2, 3)])
efr.SetImplicitFunction(sphereFunc)
efr.Modified()
fbn.SetSelectWithMarkups(True)

# Setup the callback to move the roi when the transform changes
def onTransformModified(caller, event):
    caller.GetMatrixTransformToParent(mat)
    sphereFunc.SetCenter([mat.GetElement(0, 3), mat.GetElement(1, 3), mat.GetElement(2, 3)])
    efr.Modified()

observerTag = t.AddObserver(slicer.vtkMRMLTransformNode.TransformModifiedEvent, onTransformModified)

This script will clip a fiber bundle to maintain only the fibers going through a spherical region. The script updates the clipping every time a transform named "center" is modified.

To use this script:

• Make sure SlicerDMRI is installed
• Load a fiber bundle
• Create a sphere model with a radius of 5mm
• Create a Transform and name it "center" and assign it to the sphere model
• Run the script in the Python console

After running the script, fibers going through the sphere should be conserved and others clipped. Moving the transform should automatically update the clipping.