Review Article
MRI Texture Analysis in Multiple Sclerosis
Table 1
Overview of common texture analysis approaches in MS.
| | Assessment | Utility | Statistical approach | | |
| First-order | Global assessment of pixel distribution | Self-explanatory yet lack of detail | Second-order | | | Gray-level cooccurrence matrix (GLCM) | Joint probability of two pixels having cooccurring gray level values at a given distance and direction | Multiple properties of a texture (coarseness, correlation, contrast), less sensitive to larger scales | Run length matrix (RLM) | The number of times two or more pixels having the same value in a preset direction | Several properties of a texture (coarseness), less sensitive to larger scales |
| Spectral approach | | | Fourier transform | Entire frequency profile, using sinusoid basis functions | Useful for signals without temporal changes | Wavelet transform | Scale-based frequency content, using a deformable localizing “mother” wavelet as basis function | Multiscale analysis; less intuitive and can be computation-expensive | Stockwell transform | Scale-based frequency content, using fast Fourier transform and a flexible Gaussian localizing window | Fourier-based multiscale frequency content; computation time varies by image size and algorithm |
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