DTI-Based Fiber Tracking Reveals a Multifaceted Alteration of Pennation Angle and Fiber Tract Length Upon Muscle Lengthening

Anneriet M. Heemskerk¹, Bruce M. Damon¹

DTI-based muscle fiber tracking enables 3D reconstruction of an entire muscles architecture, which is not possible with any other technique. The purpose of this study was to analyze the 3D changes in pennation angle () and fiber tract length (Lft) upon muscle lengthening and determine if these changes are heterogeneous. Each of six subjects was imaged with his/her foot in three positions. Upon muscle lengthening, decreased and Lft increased, with showing a heterogeneous pattern along the aponeurosis. This study offers exciting possibilities for better understanding of structure-function relationships in muscle.