Voxel-based morphometry
The voxel-based morphometry (VBM) is concerned with brain structures from the tomographic describe imaging by size, intensity, shape and texture parameters quantitatively. These measures are used in statistics and analyzed together with other clinical and experimental parameters.
The term voxel is made up of the words volumetric and pixel (picture element). A voxel is the three-dimensional equivalent of a pixel . The morphometry is to characterize the shape of objects by quantifiable values.
In order to analyze differences in the human brain , voxel-based morphometry checks the entire brain volume at the voxel level for proportions of gray or white matter or of cerebral fluid / bone structures. All MRI images of the examined brains are brought to a uniform size in order to evaluate the data in a standardized room. This enables comparisons between several people. First, the alignment and the size of the images of the brains are corrected: the alignment in space is done by displacement and rotation, and the change in size by scaling and shearing. Afterwards, all brain volumes are in the same standardized space, the local structural differences are highlighted. The subsequent subdivision into sections results in parametric maps with corresponding parts for gray or white matter or the cerebral fluid / bone structures. The maps are statistically analyzed in each voxel. In this way, the local structural differences can be calculated which have a different concentration or a different volume.
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- ↑ Max Planck Institute for Neurological Research: Morphometry ( Memento from July 21, 2010 in the Internet Archive )
- ↑ Clinic for Neurology at the University of Regensburg: Voxel-based Morphometry (VBM) ( Memento of the original from May 30, 2007 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.
See also
Web links
- Department of Cognitive Neurology, Institute of Neurology, Queen Square, London: Voxel-Based Morphometry - The Methods (PDF file)
- Voxel-Based Morphometry Toolbox (plug-in for SPM, based on MATLAB )