Diffusion tensor imaging alterations in patients with postconcussion syndrome undergoing exercise treatment: A pilot longitudinal study

To investigate diffusion tensor imaging characteristics in patients with postconcussion syndrome (PCS) who received exercise (n = 4) and placebo stretching (n = 4) treatments compared with a group of healthy controls (n = 15). Methods: Subjects diagnosed with PCS obtained a diffusion tensor imaging magnetic resonance image at pretreatment (baseline) and approximately 8 weeks later (follow-up). Analyses included a groupwise comparison using tract-based spatial statistics and a z-score map that investigated localized regional anomalies compared with the healthy control group projected onto the tract-based spatial statistics skeleton. Results: The tract-based spatial statistics analysis detected groupwise differences in the genu of the corpus callosum at both time points with decreased fractional anisotropy and increased radial diffusivity and mean diffusivity values. In contrast, the z-score analysis was more sensitive to heterogeneous changes in fractional anisotropy, with both low- and high-localized areas across various white matter regions, the most prevalent being the corpus callosum, anterior and superior corona radiata, and internal and external capsules. The mean number of voxels different in patients with PCS versus healthy controls was greater in all cases (baseline lower: P < .03 and higher: P < .0001; follow-up lower: P < .0001 and higher: P < .0001). The volume and location of these abnormal regions changed between the 2 diffusion tensor imaging scans, but these did not correlate with the mitigation of symptoms in the patients with PCS. Conclusions: Diffusion tensor imaging revealed spatially varying and heterogeneous localized irregularities in patients with PCS that persisted even as patient symptoms decreased and prognosis improved.