Matthew D. Budde1,2,
Lindsay Janes2, Eric Gold2, L. Christine Turtzo2,
Joseph A. Frank1,2
1Radiology
& Imaging Sciences, National Institutes of Health, Bethesda, MD, USA; 2Center
for Neuroscience & Regenerative Medicine at the Uniformed Services
University, Bethesda, MD, USA
Most studies applying diffusion tensor imaging (DTI) following traumatic brain injury (TBI) have demonstrated a decrease of white matter fractional anisotropy (FA), but increased FA has occasionally been observed. We performed DTI on rats following controlled cortical impact and developed a method to assess the microscopic anisotropy of immunostained histological sections using Fourier analysis. In the injured white matter, FA was decreased and associated with axonal and myelin degeneration. In contrast, FA increased in the peri-lesion gray matter and was associated with coherent astrogliosis. The results demonstrate that astrocytes are a potential source of anisotropy in injured brain tissue.