More patients with multiple sclerosis (MS) have multiple lesions that affect the medial longitudinal fasciculus (MLF) compared with patients with stroke; those with stroke are more likely to have lesions located at the level of the mesencephalon, according to study findings published in the Journal of Neuroimaging.

MS and ischemic stroke are the most common pathophysiologies of internuclear ophthalmoplegia (INO), a common ocular movement disorder due to MLF lesions. Study investigators sought to examine the topographical MRI features of lesions that affect the MLF in patients with MS or stroke presenting with INO.

A small team of investigators from Germany retrospectively evaluated magnetic resonance imaging (MRI) examination data from 82 patients with ischemic stroke or confirmed MS presenting with clinically confirmed INO. In this cohort, a total of 40 patients had MS and 42 patients had acute ischemic stroke. Patients with stroke were significantly older than patients with MS (78.29±11.33 vs 44.6±13.79 years, respectively; P <.001). Study investigators segmented the brainstem into the ponto-medullary junction, mid pons, upper pons, and mesencephalon to identify the location of lesions in these regions.


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Lesions affecting the MLF were found in 72.5% (n=29) of patients with MS and 90.5% (n=38) of patients with stroke (P =.04). Patients with MS showed significantly more lesions in several locations compared with patients with stroke (P <.001). The study investigators suggested that the presence of multiple lesions affecting the MLF in MS makes inflammatory demyelination due to the disease more likely. In contrast, patients with stroke had significantly more lesions at the mesencephalon level compared with those with MS (P <.001).

There was no difference between the 2 groups regarding the number of lesions at the level of the ponto-medullary junction, mid, and upper pons.

Limitations of the study included its retrospective design as well as the inclusion of only a small number of patients. Additionally, study investigators obtained MRI data from different scanners that relied on different parameters, field strengths, and protocols.

“Since MS lesions typically develop in periventricular regions,” the investigators concluded, “the high frequency of lesions in these localizations is probably a result of the close-by periventricular location to the fourth ventricle and the aqueduct.”

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.

Reference

Kleinsorge MT, Ebert A, Förster A, et al. MRI topography of lesions related to internuclear ophthalmoplegia in patients with multiple sclerosis or ischemic stroke. J Neuroimaging. Published online April 1, 2021. doi:10.1111/jon.12847