Grégoire Malandain Home

Segmentation of medical images

  • Edge detection
  • Segmentation of the brain in 3D MR images
  • Segmentation of sulcal lines in 3D MR images
  • Segmentation of angiograms

  • Segmentation of the brain in 3D MR images

    I have got two MR scans of my head (respectively 101 and 96 sagittal slices of 256x256 pixels each). The first scan is the right part of my head (without the right ear) and the second one the left part (without the left ear). Data are courtesy of General Electric, Medical System (Buc, France).


    Some original slices of the IRM data.

    First, I have registered both data sets to obtain one single 3D data volume, which is my head (still without the ears). For that task, I apply an original method of potential minimization (used to match multimodal medical images).

    The segmentation of the head is quite easy. By a single thresholding, one can really easily remove the background in MR images. Some little connected components may remain (after thresholding) in the background, but they can be removed by considering only the greatest connected component in the thresholded image.

    To obtain the 3D representation of the head, I used a surface rendering program.


    3D representation of my head (after registration and segmentation).

    The segmentation of the brain is more difficult. First, I had to find two thresholds which define the brain. The problem is that the brain is still connected to some other parts. To cut these connections, we use mathematical morphology. We apply an erosion to the result of the thresholding. Then we extract the greatest connected component of the eroded image. We obtain a kind of eroded brain. To reconstruct the brain, we apply a dilation to the eroded brain.

    To obtain the 3D representation of the brain, I used a surface rendering program.


    3D representation of my brain (after registration and segmentation).

    Having both segmentation (head and brain), I can put them together to obtain nice images, such the one below.


    3D representation of both my head and my brain.
    Click on the image to see a 3D animation (111 Ko).

    The 3D head was matched by Jacques Feldmar with an other 3D shape of my head obtained by stereoscopic reconstruction (with 2 cameras).


    One of the images used for the stereoscopic reconstruction.

    This allows either to project the texture of my face on the 3D shape coming from the MR images, or to project my brain onto one 2D image (it's called enhanced reality. Parental advertising: this image may cause offense to young people.).



    Fusion of stereo images with volumetric medical images.


    Segmentation of sulcal lines in 3D MR images

    This work was done in collaboration with Sara Fernández-Vidal.


    Three orthogonal slices of a 3-D MR image of the brain (courtesy of Dr. Neil Roberts, Liverpool university, UK).

    From a 3-D MR image of the brain, we segment first the negative mould of the cortex, including part of the grey matter.


    Three orthogonal slices of the negative mould of the cortex.

    Second, we compute its skeleton.


    Three orthogonal slices of the 3-D skeleton of negative mould of the cortex.

    The sulcal are the junction lines between the convex hull of the brain and the sulci.


    3-D representation of the brain and the sulcal lines.
    Click HERE to see a 3D animation of the sulcal lines (1.018 Ko).


    Segmentation of angiograms

    Click HERE to see a 3D animation of a 3D angiogram (584 Ko).


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    Questions, remarks to Gregoire.Malandain@sophia.inria.fr.
    Fri Dec 1 13:12:26 MET 1995