We investigated whether diffusion tensor imaging (DTI) indices of white matter integrity would offer early markers of retrograde transsynaptic degeneration (RTD) in the visual system after stroke
Objective: We investigated whether diffusion tensor imaging (DTI) indices of white matter integrity
would offer early markers of retrograde transsynaptic degeneration (RTD) in the visual system
after stroke.
Methods: We performed a prospective longitudinal analysis of the sensitivity of DTI markers of
optic tract health in 12 patients with postsynaptic visual pathway stroke, 12 stroke controls,
and 28 healthy controls. We examined group differences in (1) optic tract fractional anisotropy
(FA-asymmetry), (2) perimetric measures of visual impairment, and (3) the relationship between
FA-asymmetry and perimetric assessment.
Results: FA-asymmetry was higher in patients with visual pathway lesions than in control groups.
These differences were evident 3 months from the time of injury and did not change significantly
at 12 months. Perimetric measures showed evidence of impairment in participants with visual
pathway stroke but not in control groups. A significant association was observed between
FA-asymmetry and perimetric measures at 3 months, which persisted at 12 months.
Conclusions: DTI markers of RTD are apparent 3 months from the time of injury. This represents
the earliest noninvasive evidence of RTD in any species. Furthermore, these measures associate
with measures of visual impairment. DTI measures offer a reproducible, noninvasive, and sensitive
method of investigating RTD and its role in visual impairment
