Contribution of Diffusion Tensor MR Imaging in Detecting Cerebral Microstructural Changes in Adults with Neurofibromatosis Type 1

BACKGROUND AND PURPOSE: After an early progression of signal intensity changes in T2-weighted MR images, also known as “neurofibromatosis bright objects, ” in patients with neurofibromatosis type 1 (NF-1), there is a tendency toward regression or even disappearance in early adulthood. The purpose of this study was to investigate whether adult patients with NF-1 exhibit generalized micro-structural alterations even in normal-appearing brain regions. MATERIALS AND METHODS: Conventional and diffusion tensor MR imaging of the brain was obtained in 10 adult patients with NF-1 and 10 age-matched healthy volunteers. Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were measured in brain stem, basal ganglia, thalamus, corpus callosum, and frontal and parietooccipital white matter regions. RESULTS: Significantly increased ADC and decreased FA values were found in all regions of interest and in all patients with NF-1, irrespective of their scholastic achievement and subsequent professional performance, compared with control subjects (P .001). There were no significant correlations with the age (P .1) or with the lateralization between brain hemispheres (P .05). CONCLUSION: Diffusion tensor imaging reveals globally elevated FA and decreased ADC values in the mature brains of patients with NF-1, which is most likely a consequence of diffuse and basic alteration