Quantitative Assessment of Optic Nerve With Diffusion Tensor Imaging in Patients With Thyroid Orbitopathy

Area of Science:

• Ophthalmology
• Neurology
• Radiology

Background:

• Thyroid orbitopathy (TO) is an autoimmune condition affecting the eye socket.
• Optic nerve compromise is a severe complication of TO, potentially leading to vision loss.
• Diffusion tensor imaging (DTI) is a sensitive MRI technique for evaluating white matter integrity.

Purpose of the Study:

• To investigate optic nerve abnormalities in patients with Graves orbitopathy (GO) using DTI.
• To correlate DTI-derived parameters with clinical ophthalmic findings.

Main Methods:

• Prospective DTI scan of 28 GO patients and age/sex-matched controls.
• Comprehensive ophthalmic examinations including visual acuity, intraocular pressure, fundoscopy, and visual field analysis.
• Calculation of clinical activity scores and comparison of fractional anisotropy (FA) and mean diffusivity (MD) values.

Main Results:

• GO patients showed significantly decreased FA and increased MD values compared to controls (p < 0.001).
• Strong inverse correlation observed between FA and visual field sensitivity across optic nerve quadrants.
• Significant correlations found between proptosis degree, FA, and MD values.

Conclusions:

• DTI parameters (FA and MD) are significantly altered in patients with thyroid orbitopathy.
• These DTI changes correlate with objective ophthalmologic test results, indicating DTI's utility in assessing GO-related optic neuropathy.