Does modern radiological imaging detect lesions associated with internuclear ophthalmoplegia?
Reviewed by Lauren Hepworth

The authors present a retrospective case review including all patients with a diagnosis of internuclear ophthalmoplegia (INO) presenting to two tertiary neuro-ophthalmology centres over a five-year period. The aim of the study was to assess the sensitivity of modern radiological imaging to detect clinically detected INO. The following data was extracted: demographics, aetiology of INO, symptom duration, time between onset and magnetic resonance imaging (MRI), neuro-ophthalmic assessment, and MRI interpreted by a neuroradiologist. Patients were excluded from the analysis if MRI or reports were unavailable. The authors specified that a lesion was required in the expected location on the axial T2-weighted sequence to be deemed positive. The following data was collected from the MRI report; type of scanner, sequences used, presence and type of medial longitudinal fasciculus lesion, presence of enhancement and other brainstem / supratentorial lesions. A total of 45 patients were included in the analysis after 10 were excluded due to missing imaging data. Corresponding lesions were found in 73% of patients on MRI. The majority of cases were diagnosed with demyelinating disease (n=33), of which 75.8% had a corresponding lesion. The next most common aetiology was stroke (n=11), of which 63.6% had a corresponding lesion although diffusion-weighted imaging (DWI) was required to identify 42.9% of these lesions. Cases with identifiable lesions were more likely to have other cranial nerve involvement. Despite clinically evident INO a corresponding lesion on MRI is not seen in one quarter of demyelinating cases and one third of stroke cases. Limitations of the study included retrospective methodology, small sample size and heterogeneity of imaging protocols were noted. The authors recommend radiological investigation of INO should include T2-weighted MRI with voxel size ≤2.5mm and DWI within two weeks of onset.

Sensitivity of magnetic resonance imaging of the medial longitudinal fasciculus in internuclear ophthalmoplegia.
Tien C-W, Donaldson L, Parra-Farinas C, et al.
JOURNAL OF NEURO-OPHTHALMOLOGY
2024;44:107–11