Elevated mean diffusivity in widespread brain regions in congenital central hypoventilation syndrome

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Abstract
Purpose To investigate whether mean diffusivity (MD) values are altered in brain areas underlying cardiovascular and respiratory control in congenital central hypoventilation syndrome (CCHS). Materials and Methods Conventional and diffusion tensor imaging were performed in 15 CCHS and 30 control subjects, using a 3.0‐Tesla MRI unit. Mean diffusivity maps were calculated from diffusion‐weighted images, spatially normalized, smoothed, and compared between groups using analysis of covariance at each voxel with age as covariate. Global mean MD values of gray and white matter were determined in individual subjects and compared between groups and with age. Results Increased MD values appeared in CCHS over control subjects within multiple areas influencing breathing and cardiovascular control, including the midbrain, pons, and dorsal and ventral medulla. Other altered sites included cerebellar cortex and deep nuclei, basal ganglia, basal forebrain, and temporal and frontal cortices. Global mean MD values for gray and white matter did not differ between groups; however, gray matter MD values significantly increased with age (P < 0.02) in CCHS patients only. Conclusion Increased MD values suggest regional alterations or injury; affected areas include brainstem sites classically associated with autonomic and respiratory control. Other altered regions mediate additional physiological characteristics impaired in CCHS. J. Magn. Reson. Imaging 2006.