title: Changes of radial diffusivity and fractional anisotropy in the optic nerve and optic radiation of glaucoma patients.
abstract: Purpose of this study was to evaluate with diffusion-tensor imaging (DTI) changes of radial diffusivity (RD) and fractional anisotropy (FA) in the optic nerve (ON) and optic radiation (OR) in glaucoma and to determine whether changes in RD and FA correlate with disease severity. Therefore, glaucoma patients and controls were examined using 3T. Regions of interest were positioned on RD and FA maps, and mean values were calculated for ON and OR and correlated with optic nerve atrophy and reduced spatial-temporal contrast sensitivity (STCS) of the retina. We found, that RD in glaucoma patients was significantly higher in the ON (0.74 ± 0.21 versus 0.58 ± 0.17·10(-3) mm(2) s(-1); P < 0.05) and OR (0.79 ± 0.23 versus 0.62 ± 0.14·10(-3) mm(2) s(-1); P < 0.05) compared to controls. Aside, FA was significantly decreased (0.48 ± 0.15 versus 0.66 ± 0.12 and 0.50 ± 0.20 versus 0.66 ± 0.11; P < 0.05). Hereby, correlation between changes in RD/FA and optic nerve atrophy/STCS was observed (r > 0.77). In conclusion, DTI at 3 Tesla allows robust RD and FA measurements in the ON and OR. Hereby, the extent of RD increase and FA decrease in glaucoma correlate with established ophthalmological examinations.
authors.affiliation: Department of Neuroradiology, University of Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen, Germany. tobias.engelhorn@uk-erlangen.de
authors.forename: Tobias
authors.initials: T
authors.lastname: Engelhorn
authors.forename: Georg
authors.initials: G
authors.lastname: Michelson
authors.forename: Simone
authors.initials: S
authors.lastname: Waerntges
authors.forename: Marlen
authors.initials: M
authors.lastname: Otto
authors.forename: Ahmed
authors.initials: A
authors.lastname: El-Rafei
authors.forename: Tobias
authors.initials: T
authors.lastname: Struffert
authors.forename: Arnd
authors.initials: A
authors.lastname: Doerfler
mesh_terms: D000328:Adult; D000368:Aged; D016880:Anisotropy; D015350:Contrast Sensitivity; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005901:Glaucoma / Q000175:diagnosis* / Q000503:physiopathology; D006801:Humans; D008875:Middle Aged; D009900:Optic Nerve / Q000473:pathology* / Q000503:physiopathology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity