Hyperintense Optic Nerve due to Diffusion Restriction: Diffusion-Weighted Imaging in Traumatic Optic Neuropathy.

Area of Science:

• Neuroimaging
• Ophthalmology
• Trauma Imaging

Background:

• Traumatic optic neuropathy (TON) can present with abnormal signal intensity in the optic nerve on diffusion-weighted imaging (DWI) due to diffusion restriction.
• Assessing optic nerve changes is crucial for diagnosing and managing TON.

Purpose of the Study:

• To evaluate optic nerve hyperintensity on DWI in patients with TON.
• To compare apparent diffusion coefficient (ADC) values between injured and uninjured optic nerves.
• To determine the relationship between ADC values and visual acuity in TON.

Main Methods:

• Retrospective analysis of 29 patients with TON who underwent MR imaging with DWI.
• Comparison of ADC values between injured optic nerves and contralateral uninjured nerves.
• Correlation analysis between ADC values, optic nerve hyperintensity, and initial visual acuity.

Main Results:

• Optic nerve hyperintensity on DWI was observed in 8 of 29 patients (27.6% sensitivity, 100% specificity).
• Mean ADC values were significantly lower in the injured optic nerve compared to the uninjured nerve (P = .003).
• A moderate-to-strong correlation (R = 0.7, P = .02) was found between lower ADC values and poorer visual acuity.

Conclusions:

• Optic nerve hyperintensity on DWI is a specific imaging marker for traumatic optic neuropathy.
• Reduced ADC values in the optic nerve, when combined with hyperintensity, can serve as a surrogate marker for visual acuity in TON.