Introduction. Leber's hereditary optic neuropathy (LHON) is a mitochondrial disease characterized by acute or subacute bilateral loss of central vision. A clinical subtype of LHON presents T2-weighted magnetic resonance imaging (MRI) lesions indistinguishable from those of multiple sclerosis (MS) (LHON-MS). Ojectives. To assess the severity of optic nerve (ON) damage in patients with LHON, using conventional MRI and magnetization transfer imaging (MTI); to assess the presence and extent of macro- and microscopic pathology in the brain and cervical cord of these patients using MT ratio (MTR) and mean diffusivity (D) histogram analysis. Patients and methods. Fourteen LHON patients (10 with isolated ON involvement and 4 with LHON-MS) and 20 age- and sex-matched controls were studied. The following sequences were acquired: (a) brain: dual-echo, T1-weighted, MT and echo planar diffusion-weighted (DW); (b) ON: T1-weighted and MT; and (c) cervical cord: fast-short tau inversion recovery (STIR) and MT. We measured the volumes and average MTR of both ONs. MTR and D histograms of the normal-appearing brain tissue (NABT) and MTR histograms of the whole cervical cord tissue were obtained from all patients and controls. For each histogram, the peak height, the peak location, the average MTR and the average D were analyzed. Results. The mean values of ON volumes and were significantly lower in LHON patients than in healthy controls (P<0.001). ON volumes and MTR values were lower in LHON-MS than in LHON patients. All four patients with LHON-MS showed brain and cervical cord MRI lesions. Mean NABT- MTR (P=0.02) and peak height (P=0.007) were significantly lower in LHON patients than in controls, whereas there were no significant differences for cervical cord MTR histogram-derived measures. Average D was lower (P=0.04) in LHON patients than in controls. Patients with LHON-MS had lower values of all NABT and cord MTR histogram metrics than those with LHON. Conclusions. The severity of ON pathology in LHON is measurable in vivo using MRI and MTI. MTR and D histogram analysis suggest that microscopic brain damage occurs in LHON and that it is more severe in the MS-like from of this disease. In patients with LHON-MS, the cord pathology is confined to macroscopic lesion.
MRI, MTI and DWI study of the optic nerve, brain and cord in patients with leber hereditary optic neuropathy
Inglese M.;Mancardi G. L.;Ghezzi A.;
2000-01-01
Abstract
Introduction. Leber's hereditary optic neuropathy (LHON) is a mitochondrial disease characterized by acute or subacute bilateral loss of central vision. A clinical subtype of LHON presents T2-weighted magnetic resonance imaging (MRI) lesions indistinguishable from those of multiple sclerosis (MS) (LHON-MS). Ojectives. To assess the severity of optic nerve (ON) damage in patients with LHON, using conventional MRI and magnetization transfer imaging (MTI); to assess the presence and extent of macro- and microscopic pathology in the brain and cervical cord of these patients using MT ratio (MTR) and mean diffusivity (D) histogram analysis. Patients and methods. Fourteen LHON patients (10 with isolated ON involvement and 4 with LHON-MS) and 20 age- and sex-matched controls were studied. The following sequences were acquired: (a) brain: dual-echo, T1-weighted, MT and echo planar diffusion-weighted (DW); (b) ON: T1-weighted and MT; and (c) cervical cord: fast-short tau inversion recovery (STIR) and MT. We measured the volumes and average MTR of both ONs. MTR and D histograms of the normal-appearing brain tissue (NABT) and MTR histograms of the whole cervical cord tissue were obtained from all patients and controls. For each histogram, the peak height, the peak location, the average MTR and the average D were analyzed. Results. The mean values of ON volumes and were significantly lower in LHON patients than in healthy controls (P<0.001). ON volumes and MTR values were lower in LHON-MS than in LHON patients. All four patients with LHON-MS showed brain and cervical cord MRI lesions. Mean NABT- MTR (P=0.02) and peak height (P=0.007) were significantly lower in LHON patients than in controls, whereas there were no significant differences for cervical cord MTR histogram-derived measures. Average D was lower (P=0.04) in LHON patients than in controls. Patients with LHON-MS had lower values of all NABT and cord MTR histogram metrics than those with LHON. Conclusions. The severity of ON pathology in LHON is measurable in vivo using MRI and MTI. MTR and D histogram analysis suggest that microscopic brain damage occurs in LHON and that it is more severe in the MS-like from of this disease. In patients with LHON-MS, the cord pathology is confined to macroscopic lesion.
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