Does diffusion-tensor MR imaging provide accurate tracing of specific white matter tracts that correspond to actual anatomic and functional units in the central nervous system?

By using healthy common marmoset monkeys, Yamada et al traced the retinogeniculate pathways with ultra high-spatial-resolution manganese-enhanced magnetic resonance (MR) imaging and diffusion-tensor imaging at 7 T. Both methods were compared with morphologic findings described in published histopathologic studies. Both methods provided identical tracing of the optic nerve, optic chiasm, and optic tracts to the level of the lateral geniculate nucleus (LGN), faithfully reproducing the crossing of the nasal portion of the optic nerve at the level of the chiasm into the contralateral optic tract. This study strongly suggests that diffusion-tensor imaging, a noninvasive method that can be used in human research and clinical practice, has the potential to provide accurate tracing of specific white matter tracts that correspond to actual anatomic and functional units in the central nervous system.