Magnetization transfer and diffusion tensor MR imaging of the optic radiations and calcarine cortex from patients with Leber's hereditary optic neuropathy

Optic nerve abnormalities are easily detectable in patients with Leber's hereditary optic neuropathy (LHON), using magnetic resonance imaging (MRI). However, the presence of structural chances in the optic radiations and calcarine cortex of these patients is still an unresolved issue. In this study, we obtained magnetization transfer WT) and diffusion tensor (DT) MRI to investigate the integrity of these structures in patients with LHON. Dual echo, MT- and DT-MRI scans of the brain were obtained from 10 men with LHON and 10 healthy sex- and age-matched controls. After image co-registration, we obtained MT ratio (MTR), average diffusivity ((D) over bar) and fractional anisotropy (FA) maps. MTR, (D) over bar and FA values for the white matter of the optic radiations and MTR and (D) over bar values for the calcarine cortex were obtained using a region of interest (ROD analysis. No macroscopic abnormalities were detected in any of the scans from LHON patients and controls. No statistically significant differences of MTR, (D) over bar or FA values were found for any of the regions studied in LHON patients and healthy controls. Our results suggest that, in patients with LHON, the optic radiations and the calcarine cortex are spared from structural damage, both at a macroscopic and a microscopic level. (C) 2001 Elsevier Science B.V. All rights reserved.