Figure 5: Muscle fiber tracking of the tibialis anterior (TA) muscle in vivo. Examples of “fiber tracking” from processed diffusion tensor imaging (DTI). The image shows modeling of fiber tracks based on the DTI data in the TA muscles of a wild-type (wt) mouse and an mdx mouse in the noninjured and injured sides. Even with this mild injury protocol that shows only minimal change in the T2 signal, the injured TA is readily identified by an apparent interruption in the vertical orientation of the tracks (arrows). Tractography is only a visual depiction of the DTI parameters. It is useful in providing accurate representation of the true anatomy of muscles but less so after injury. The colored bands are just where the regions of interest were drawn to outline the TA. Note that the mdx T2 image shows regions of hyperintensity, as seen in Figure 4.