Accessing Segmentation Layer Visibility By View

Development
1

Hi All,

I’m curious if there is a way to show particular segmentation nodes on each of four different views in a two over two layout programmatically. An example of doing this for background volumes would be as follows:

volumes_of_interest = [pre_T1, pre_ADC, post_T1, post_ADC]

viewNodes = slicer.mrmlScene.getNodesByClass('vtkMRMLSliceCompositeNode')
for i,viewNode in enumerate(viewNodes):

        viewNode.SetBackgroundVolumeID(self.volumesLoad[i].GetID())

In our use case we make unique segmentations on two different MRI sequences before and after an intervention. Being able to view and touch-up all four segmentations would be helpful.

I understand that Segmentations play by different rules. I tried exploring SetDisplayVisibility, but it seems to only act globally on all views.

Any suggestions are much appreciated.

Best,

Brett

2

You can add multiple segmentation display nodes to have one for each view. Then set view node ID and visibility in each display node.

3

What do you mean by specifically by a segmentation display node?

In the API vtkMRMLDisplayableNode doesn’t seem have a view node ID attribute and vtkMRMLSegmentationNode doesn’t seem to have a visibility attribute.

4

http://apidocs.slicer.org/master/classvtkMRMLSegmentationDisplayNode.html

Create one using slicer.mrmlScene.AddNewNodeByClass and add it to the segmentation node using its AddAndObserveDisplayNodeID method.

These are display node methods.

Example:

# Get segmentation node, for the rest, we assume that there are 3 segments, with default names/ids
segmentationNode=getNode('Segmentation')

# Get display node that is used by default for all views
segmentationDisplayNode1=segmentationNode.GetDisplayNode()

# Add one more display node
segmentationDisplayNode2=slicer.mrmlScene.AddNewNodeByClass('vtkMRMLSegmentationDisplayNode')
segmentationNode.AddAndObserveDisplayNodeID(segmentationDisplayNode2.GetID())

# Display node 1: show only in Red slice view, show only segment 3
segmentationDisplayNode1.SetViewNodeIDs(['vtkMRMLSliceNodeRed'])
segmentationDisplayNode1.SetSegmentVisibility('Segment_1',False)
segmentationDisplayNode1.SetSegmentVisibility('Segment_2',False)

# Display node 2: show only in Yellow nad Green slice views, show only segment 1
segmentationDisplayNode2.SetViewNodeIDs(['vtkMRMLSliceNodeYellow', 'vtkMRMLSliceNodeGreen'])
segmentationDisplayNode2.SetSegmentVisibility('Segment_2',False)
segmentationDisplayNode2.SetSegmentVisibility('Segment_3',False)
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5

Hi Andras,

This is really helpful! Thanks so much for providing the examples.

I also found this DisplayNode method that similarly achieves only showing segmentations in select views.

segmentationDisplayNode = segmentNode.GetDisplayNode()    
sliceNode = 'vtkMRMLSliceNodeRed'
segmentationDisplayNode.SetDisplayableOnlyInView(sliceNode.GetID())
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