Neuroimaging in thyroid eye disease: A systematic review

Thyroid eye disease (TED) is an organ-specific autoimmune disease secondary largely to hyperthyroid Graves' disease, which profoundly affects patients' visual function, appearance, and physical and mental well-being. Emerging neuroimaging studies have reported alterations in the brains of patients with TED, suggesting that the impact of this autoimmune disease may extend beyond the orbit. This systematic review aims to consolidate the neuroimaging evidence that describes the brain alterations of TED. We analyzed information from thirty-one related studies involving 1349 TED patients and 710 healthy controls, employing multimodal neuroimaging techniques such as structural magnetic resonance imaging (MRI), functional MRI, diffusion MRI, and metabolic MRI. These studies define the brain alterations in regions associated with vision, cognition, and emotion regulation, such as gray matter volume changes, altered functional connectivity and activity, and microstructural modifications, revealing the neurological impact of TED beyond the orbit. Notably, there was convergence across these studies indicating predominant abnormalities within the occipital and parietal lobes. This review underscores the critical role of advanced neuroimaging techniques in unraveling the complex neuropathological mechanism of TED, laying a foundation for future research and potential therapeutic targets.