Altered diffusivity of the subarachnoid cisterns in the rat brain following neurological disorders

Background: Although changes in diffusion characteristics of the brain parenchyma in neurological disorders are widely studied and used in clinical practice, the change in diffusivity in the cerebrospinal fluid (CSF) system is rarely reported. In this study, free water diffusion in the subarachnoid cisterns and ventricles of the rat brain was examined using diffusion magnetic resonance imaging (MRI), and the effects of neurological disor-ders on diffusivity in CSF system were investigated. Methods: Diffusion MRI and T2-weighted images were obtained in the intact rats, 24 h after ischemic stroke, and 50 days after mild traumatic brain injury (mTBI). We conducted the assessment of diffusivity in the rat brain in the subarachnoid cisterns around the midbrain, as well as the lateral ventricles. One-way ANOVA and Kruskal-Wallis test were used to evaluate the change in mean diffusivity (MD) and MD histogram, respectively, in CSF system following different neurological disease. Results: A significant decrease in the mean MD value of the subarachnoid cisterns was observed in the stroke rats compared with the intact and mTBI rats (p < 0.005). In addition, the skewness (p < 0.002), maximum MD (p < 0.002), and MD percentiles (p < 0.002) in the stroke rats differed significantly from those in the intact and mTBI rats. By contrast, no difference was observed in the mean MD value of the lateral ventricles among three groups

Automated summary

This study investigated the diffusion of free water in the cerebrospinal fluid (CSF) system of rat brains using diffusion magnetic resonance imaging (MRI). The results showed a significant decrease in mean diffusivity in the subarachnoid cisterns of stroke rats compared to intact rats and rats with mild traumatic brain injury (mTBI). The diffusivity characteristics in stroke rats also differed significantly from the other two groups in terms of skewness, maximum diffusivity, and diffusivity percentiles. However, there was no difference in mean diffusivity in the lateral ventricles among the three groups.