Correlation of diffusion tensor imaging metrics with neurocognitive function in Chiari I malformation.

BACKGROUND: The aim of this study was to examine changes in normal-appearing deep gray and white matter regions of the brain in patients with Chiari I malformation compared with controls using diffusion tensor imaging (DTI) and to correlate these changes with neuropsychological (NP) test scores.

METHODS: Conventional magnetic resonance imaging, DTI, and neuropsychological tests were performed on 10 patients (median age 27 years, range 18 to 36 years) with Chiari I malformation and 10 age/sex-matched healthy controls. Diffusion tensor imaging metrics (fractional anisotropy, mean diffusivity [MD], radial diffusivity [RD], and axial diffusivity [AD]) were quantified in different regions of the brain in patients as well as in controls using the region of interest (ROI) method. An independent Student t test was performed to evaluate differences in diffusion tensor imaging metrics from patients and controls. Pearson's correlation coefficient was also used to determine association between NP test scores and DTI metrics in patients.

RESULTS: Significantly reduced fractional anisotropy with increased MD was found in genu, splenium, fornix, and putamen in patients compared with controls; however, RD significantly increased in fornix and cingulum, whereas AD significantly increased in putamen, thalamus, and fornix as compared with controls. NP tests were found to be abnormal in patients with Chiari I malformation compared with controls, and some of these tests showed significant correlation with DTI metrics.

CONCLUSIONS: We conclude that abnormal changes in the DTI metrics in patients with Chiari I malformation indicate microstructural abnormalities in different brain regions that may be associated with neurocognitive abnormalities.