White matter abnormalities in tuberous sclerosis complex: a systematic review of diffusion tensor imaging studies.

BACKGROUND: Tuberous sclerosis complex (TSC) is a genetic disorder, characterized by benign tumors in various organs, arising from mutations in tumor suppressor genes (TSC1 or TSC2). Diffusion tensor imaging (DTI) is a magnetic resonance imaging-based method that measures the microstructural characteristics of different tissues by assessing the changes in multiple diffusion-related indices. METHODS: A systematic search on PubMed, Web of Science, and EMBASE was conducted for relevant records on November 24, 2023. we identified and reviewed the eligible articles that reported the changes in DTI measurements in the brains of patients with TSC compared to the control groups. RESULTS: 20 studies were reviewed. Most of the included studies had a prospective design (n = 17). Our findings consistently demonstrated reduced fractional anisotropy and increased diffusivity metrics in various white matter tracts of individuals with TSC relative to controls. These alterations were predominantly observed within the corpus callosum, internal and external capsules, and association fibers of the cerebral lobes. CONCLUSION: Our findings suggest microstructural white matter alterations in patients with TSC. However, the limited number of included studies, small sample sizes, and heterogeneity in analysis methods and the studied regions necessitate further investigation. Future research is crucial to elucidate the precise relationship between the altered white matter structure and both the clinical manifestations of patients with TSC and the underlying pathogenesis of the disease.