Skeletal muscle deformation analysis using diffusion tensor magnetic resonance imaging

Abstract

Skeletal muscles are highly organized tissues formed of ber bundles packed together. Muscle bers have distinct orientations which makes them a favorable subject for di usion tensor imaging (DTI) based analyses. DTI provides in vivo measures revealing the structural characteristics of tissues based on di usion anisotropies of water molecules within structures. Local ber orientations can be extracted for deformation analysis of the spatial distribution of di usion and strain characteristics along ber directions. This work aims to present a framework for the assessment of local strain and di usion anisotropy changes as skeletal muscles of human subjects (n=3) become deformed by moving from a exed con guration (150 knee angle) to an extended con guration (180 knee angle). Changes between the di usion anisotropy indices and strain coe cients along ber tracts between the tibialis anterior muscle ends are computed, visualized and modeled to account for heterogeneous changes in the microstructure resulting from deformation. Results are indicators of e ects of myofascial force transmission on human muscles in vivo, including local di erences between sarcomere length changes (maximal lengthening and shortening equals 34.62% and -33.78%, respectively) and di usivity changes in the proximo-distal direction as well as in the transverse plane. The demonstrated methodology also provides an image processing toolbox for the thorough analysis of skeletal muscles. Final results presented here can have clinical implications by contributing to explaining and improving the treatment options of movement limitations.