Although conventionaltechniques ofmagneticresonanceimaging (MRI) play acrucialrolein examining the peripheral nervous system(PNS), they are notcapable of providing any information about functional properties ofthe peripheral nervetractsand the orientation and localization ofaxons. However, other MRmethods, such as diffusion-weighted imaging (DWI), diffusion tensor imaging (DTI), MRtractography (MRT)and MR neurography (MRN), [1–4] may enabletheevaluation ofthesefunctionaland structural properties. DWI is based on the diffusion ofwater molecules in tissues. DTI isaformofDWI, whichmodels diffusion by tensor, mathematically described asasymmetric 3 × 3 matrix thatcharacterizes diffusion in 3Dspace(measured in 6 or more different directions)and graphically represented by an ellipsoid oran orientation distribution function (ODF). Diffusion tensorcan be described by itseigenvectorsand eigenvalues (λ1 , λ2 ,and λ3 ) fromwhich thecurrently used diffusion indicesare derived.
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