EMSegmenter-Tasks:MRI-Human-Brain-Hemisphere

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Description

Single channel automatic segmentation of t1w-MRI brain scans into the major tissue classes (gray matter, white matter, csf). The task can only be applied to t1w brain scan showing parts of the skull and neck. The pipeline consist of the following steps:

  • Step 1: Perform image inhomogeneity correction of the MRI scan via N4ITKBiasFieldCorrection (Tustison et al 2010)
  • Step 2: Register the atlas to the MRI scan via BRAINSFit (Johnson et al 2007)
  • Step 3: Compute the intensity distributions for each structure

Compute intensity distribution (mean and variance) for each label by automatically sampling from the MR scan. The sampling for a specific label is constrained to the region that consists of voxels with high probability (top 95%) of being assigned to the label according to the aligned atlas.

  • Step 4: Automatically segment the MRI scan into the structures of interest using EM Algorithm (Pohl et al 2007)

Anatomical Tree

  • root
    • background (BG)
      • air (AIR)
      • skull (skull)
    • intracranial cavity (ICC)
      • white matter (WM)
      • grey matter (GM)
      • cerebrospinal fluid (CSF)

Atlas

Atlas was generated based on 82 scans and corresponding segmentations provided by Psychiatry Neuroimaging Laboratory, BWH. We registered the scans to a preselected template via Warfield et al. 2001.
Image Dimension = 256 x 256 x 124
Image Spacing = 0.9375 x 0.9375 x 1.5

EMSegmenter MRI-Human-Brain Template 420x420.png EMSegmenter MRI-Human-Brain CSF 420x420.png EMSegmenter MRI-Human-Brain GM 420x420.png EMSegmenter MRI-Human-Brain WM 420x420.png
Template (T1) CSF GM WM

This task is using two parcellation maps: atlas_whitematter_hem and atlas_greymatter_hem to divide the segmentation into left and right regions.

Result

Acknowledgment

The construction of the pipeline was supported by funding from NIH NCRR 2P41RR013218 Supplement.

Citations