Tractography: Possible Applications in Musculoskeletal Radiology

Abstract

Tractography (or fiber tracking) consists of three-dimensional modeling of the preferential movement of water molecules in the form of fiber tracks from the tensor field information. This technique allows a new approach for the microarchitectural analysis of anisotropic structures such as nerves, white matter, and muscles. Many disorders have been studied including cervical myelopathy, carpal tunnel syndrome, nerve root compression, and nerve tumors. Muscles have been less evaluated. Tractography is still a research technique, and its validation and widespread routine clinical use will require a good deal of work toward a harmonization of the MRI protocols and data postprocessing methods.

Potential Role of MRI Imaging for Myofascial Pain: A Scoping Review for the Clinicians and Theoretical Considerations

“… 28 The application of DTI has most frequently been done in the central nervous system, so a great deal of the methodology for muscle fiber tracking has been borrowed and applied using tools already available. 29 The DTI approach is able to differentiate between functionally different muscles in the same body region as well as differentiate between injured and uninjured muscle, based on their water diffusive properties. 30–32 …”

“…28 The application of DTI has most frequently been done in the central nervous system, so a great deal of the methodology for muscle fiber tracking has been borrowed and applied using tools already available. 29 The DTI approach is able to differentiate between functionally different muscles in the same body region as well as differentiate between injured and uninjured muscle, based on their water diffusive properties. [30][31][32] Using fiber tracking, a method that aligns directionality from the primary eigenvectors for each voxel, DTI has also been shown to differentiate muscle fiber orientation and determine resultant force vectors of muscular components in the quadriceps.…”

Diffusion tensor imaging in the musculoskeletal and peripheral nerve systems: from experimental to clinical applications

“…Molecular mobility in human tissues is usually non-isotropic, which means that diffusion does not occur equally in all directions; protein fibres, cell membranes and myelin sheath tend to hinder water diffusion [ 13 ].…”

“…Acquisition time is largely variable, as standardised protocols are still lacking. As an example, six directions may be enough for the median nerve, about 15–25 vector directions are needed for the brachial plexus, while 10–12 different vector directions are needed for muscular structures [ 13 ]. Regarding the b-values, there is no unanimous agreement on what to use in musculoskeletal imaging [ 17 ].…”

New Imaging Methods for Non-invasive Assessment of Mechanical, Structural, and Biochemical Properties of Human Achilles Tendon: A Mini Review

“…The integrity of tissues is then assessed by the predominant direction, intensity and isotropic characteristics of water diffusion within the biological structure. For instance, DTI is used in skeletal muscle to determine potential exercise-induced structural alterations (Fouré et al, 2015a ) and potential changes in muscle architecture (i.e., fiber length and pennation angle) with muscle fiber tractography (Cotten et al, 2015 ). For now, only a few studies have assessed anisotropy/microarchitecture of the tendon (Momot et al, 2010 ) in animals (Wellen et al, 2005 ; Helmer et al, 2006 ; Gupta et al, 2010 ) and in humans (Sarman et al, 2015 ).…”