Optic nerve MRI findings in Leber's hereditary optic neuropathy.

Purpose: This study aimed to investigate the characteristics of magnetic resonance imaging (MRI) of lesions in Lebers hereditary optic neuropathy (LHON).

Study design: Retrospective study.

Methods: We examined the clinical characteristics and MRI scans of lesion locations in 34 LHON cases (68 eyes) with m.11778G>A mutation, examined within six months of onset who had detailed MRI imaging records available.

Results: The median age was 36.5 (range: 10-75) years, with 26 male cases. MRI lesions were observed in 15 cases, with the following distribution: isolated intraorbital lesions in 7 cases, intraorbital + optic canal lesions in 1 case, intraorbital + optic canal + intracranial lesions in 1 case, optic canal + intracranial lesions in 1 case, optic canal + intracranial + chiasmal lesions in 1 case, intracranial + chiasmal lesions in 3 cases, and chiasmal + optic tract lesions in 1 case. There were no significant differences in clinical characteristics between patients with and without MRI lesions. Cases with chiasmal lesions tended to be younger (chiasmal lesion group [n=5] vs. non-chiasmal lesion group [n=29]: median age 25 [range: 11-30] years vs. 44 [range: 10-75] years, p=0.02, Mann-Whitney U test), although there were no significant differences in sex or time to MRI imaging.

Conclusion: MRI lesions can extend from the intraorbital optic nerve to the chiasm and tract. Consistent with previous reports, chiasmal involvement was frequently observed and was more prevalent in younger patients. Recognition of these characteristic MRI and clinical findings is crucial in the differential diagnosis of subacute progressive optic neuropathy.