Table of Contents

Threshold Segmentation Options

Threshold is a contouring tool that allows you to segment objects based on a fixed range of intensity values.

The tool can be used on MR, CT, PET images and images generated with Brainlab Elements Contrast Clearance Analysis to extract contrast enhanced structures, such as:

  • Bone structures
  • Blood vessels
  • Burned-in objects (e.g., BOLD fMRI, TMS)
  • Activation hot-spot



ROI for Threshold to be applied. Can be set to:

  • Sphere: Uses all voxels inside a user-defined sphere.
  • Full Volume: Uses the complete image set.
  • Any segmented object that is available.

Threshold intensity slider: Adjust the intensity range to be used for segmentation.


  • Can be used to set the number of independent components or voxel islands that the segmentation results in.
  • Set to 1 to use only the biggest voxel island.
  • Set to All to use all voxel islands.

Select Apply to segment the object based on the values in the controls.

Example of threshold based segmentation of 3D DSA contrast enhanced image data: Separation of vascular structure with Sphere ROI.

Art-No. 60919-79EN

Date of issue: 2019-12-05