Magnetic resonance imaging magnetisation transfer imaging anddiffusion weighted imaging correlates of optic nerve brain andcervical cord damage in Lebers hereditary optic neuropathy

摘要

OBJECTIVES—Leber's hereditary optic neuropathy (LHON) is a mitochondrial disease leading to bilateral loss of central vision and severe optic nerve atrophy. A subtype of LHON presents additional clinical and MRI aspects indistinguishable from those of multiple sclerosis (MS) (LHON-MS). In patients with LHON or LHON-MS, an assessment was made of (a) the severity of optic nerve damage, using MRI and magnetisation transfer imaging (MTI), and (b) the presence and extent of macroscopic and microscopic pathology in the brain and cervical cord, using MRI and MT ratio (MTR) and mean diffusivity () histogram analysis.
METHODS—Ten patients with LHON, four with LHON-MS, and 20 age and sex matched healthy controls were studied. For the optic nerve and the brain, dual-echo turbo spin echo (TSE), T1 weighted spin echo, and MT images were obtained. For the brain, fast fluid attenuated inversion recovery (fast FLAIR) and diffusion weighted images were also obtained. For the cervical cord, fast short tau inversion recovery (STIR) and MT imageswere obtained. The volume and the average MTR value of both the opticnerves were measured. MTR and histograms of the normal appearing brain tissue (NABT) and MTRhistograms of the whole cervical cord tissue were created.
RESULTS—The meanvalues of optic nerve volumes and MTR were significantly lower inpatients with LHON than in healthy controls. Mean NABT-MTR histogrampeak height was significantly lower in patients with LHON than incontrols, whereas no significant difference was found for any of thecervical cord MTR histogram derived measures. Averagediffusivity() was higher inpatients with LHON than in controls. Optic nerve volume and MTR valueand mean NABT-MTR were lower in patients with LHON-MS than in thosewith LHON.
CONCLUSIONS—Theseverity of optic nerve pathology in LHON is measurable in vivo usingMRI and MTI. MTR and histogramanalysis suggests that microscopic brain damage occurs in LHON and thatit is more severe in the MS-like form of the disease.