Optic nerve diffusion tensor imaging parameters and their correlation with optic disc topography and disease severity in adult glaucoma patients and controls.

Purpose: To evaluate optic nerve diffusion tensor imaging (DTI) parameters in glaucoma patients and controls, and to correlate DTI parameters with the rim area obtained with Heidelberg retina tomography (HRT) and with the severity of glaucomatous damage using the Glaucoma Staging System. Design: Pilot study. Methods: Twenty-seven patients with glaucoma and 12 control subjects underwent DTI and HRT imaging. Main outcome measures included: fractional anisotropy, mean diffusivity, axial diffusivity, radial diffusivity, HRT rim area, and Glaucoma Staging System stage. Results: In group comparison, mean diffusivity (1.33 vs. 0.91 mu m(2)/ms, P = 0.0002), axial diffusivity (1.70 vs. 1.43 mu m(2)/ms, P = 0.036), and radial diffusivity (1.24 vs. 0.71 mu m(2)/ms, P 0.05). Conclusions: DTI may be a useful technique for detection and evaluation of glaucomatous damage in the optic nerve, particularly for patients in whom conventional imaging and perimetry are not possible. Future studies are needed to evaluate how DTI parameters change longitudinally with glaucomatous damage within the visual pathways and address cerebrospinal fluid partial volume effects in diffusion tensor quantification, especially for patients with advanced glaucoma stage.