Both the optic nerve enhancement pattern and the white matter lesion distribution, as seen in magnetic resonance imaging (MRI) of the brain and orbit, can be used in differentiating and diagnosing anterior ischemic optic neuropathy and optic neuritis in patients with a, according to published research otherwise ambiguous clinical diagnosis help in the British Journal of Ophthalmology.
Researchers conducted a retrospective case series review of patients undergoing MRI to determine the role of MRI in assessing optic nerve damage in anterior optic neuropathy or optic neuritis. The aim of the current study was to find out which MRI features, if any, would help differentiate these diagnoses.
Patients included in the study presented to an emergency room in Switzerland between 2010 and 2018 with new visual disorders of unknown etiology; These patients were then given emergency brain MRI or special orbital sequences, or both. Enrolled patients also had data from a concurrent ophthalmic examination.
The total cohort consisted of 50 patients (mean age 53.17 ± 15.87), of whom 29 were diagnosed with arteritic or non-arterial anterior ischemic optic neuropathy (mean age 62.47 ± 9.99 years) and 22 were diagnosed with optic neuritis (mean age, 41.34 ± 14.05). The age difference between the groups was statistically significant, and optic neuritis was more common in women.
The time between the onset of symptoms and the MRI evaluation was between 5 hours and 30 days. The MRI scoring consisted of 2 independent evaluators. Good agreement was found for all parameters (Cohen-Kappa, 0.998). Researchers used a step-by-step model to automatically select predictive variables, resulting in a model that was dependent on white matter lesions, central bright spot, optic nerve enhancement, diffusion weighted imaging (DWI) of the optic nerve and optic nerve sheath.
A dominance analysis was also performed to assess the contribution of each of these different parameters to the prediction. The researchers found that improving the optic nerve played the largest role in disease classification (McFadden Index, 0.35). The distribution made a similarly high contribution (McFadden index 0.32), while the central bright spot, the DWI optic nerve and the optic nerve sheath had index values of 0.14, 0.07 and 0.07, respectively.
Using the 3 most important parameters – distribution, gain and central bright spot – the modeling showed a classification accuracy of 0.92. Using only 2 parameters – distribution and improvement – the classification accuracy was 0.90.
The researchers also tested the diagnostic value of DWI sequences for differentiating between diseases, using only the DWI restriction for modeling; The predictive accuracy of this model was 0.68. Conversely, using all parameters without a DWI produced a model with the same classification accuracy as the full model that included all parameters (0.98).
Limitations of the study included the retrospective nature of the research and the lack of a unified MRI protocol for the eye sockets, as well as the recent availability of new DWI techniques to supplement the range of MR sequences that were not available at the time of the study.
“Our results suggest that in patients with vision loss who are in doubt about the clinical diagnosis and MRI is acquired, neuroradiologists should focus on imaging findings that help differentiate the diagnosis,” the researchers said. “A prospective study of atypical clinical ophthalmic cases should be considered to validate these observations,” they concluded.
Petroulia VD, Brugger D, Hoepner R, et al. MRI signs helpful in differentiating patients with anterior ischemic optic neuropathy and optic neuritis. Br J Ophthalmol. Published online July 19, 2021. doi: 10.1136 / bjophthalmol-2021-319537
This article originally appeared on Ophthalmology Advisor